7 DAYS Effect of Irrigation Pumping on Desert Pupfish Habitats in i EARTH we Ash Meadows, Nye County, Nevada GEOLOGICALSURVEYPROFESSIONALINAPER927 JUN 14 1976 DOCUMENTS DEPARTMENT JUL 9 7976 UBRARY UNIVERSITY OF CALIFORNIA Effect of Irrigation Pumping on Desert Pupfish Habitats in Ash Meadows, Nye County, Nevada By W.W. DUDLEY, JR., and JD. LARSON GEOLOGICAL SURVEY PROFESSIONAL PAPER 927 UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON i 1976 14886 UNITED STATES DEPARTMENT OF THE INTERIOR THOMAS S. KLEPPE, Secretary GEOLOGICAL SURVEY V. E. McKelvey, Director Dudley, W. W. Effect of irrigation pumping on desert pupfish habitats in Ash Meadows, Nye County, Nevada. (Geological Survey Professional Paper 927) Bibliography: p. Supt. of Docs. No.: 119.6:927 1. Deirls Hole pupfish. 2. Irrigation—Environmental aspects—Nevada—Nye Co. 3. Water table—Nevada—Nye Co. 4. Fishes, Fresh-water—Nevada—Nye Co. I. Larson, J. D., joint author. 11. Title. 111. Series: United States Geological Survey Professional Paper 927. QL638.C96D82 597'.53 75—619366 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, DC. 20402 Stock Number 024-001-02825—5 CONTENTS Page Abstract ............................................... 1 Introduction ............................................ 1 Purpose, scope, and organization ...................... 4 Location system .................................... 4 Acknowledgments .................................. 4 Regional setting ........................................ 4 Physiography ....................................... 4 Climate ............................................ 5 Hydrogeology ...................................... 5 Regional aquifer system .......................... 5 Local aquifer system ............................. 9 Hydrologic features of Ash Meadows ...................... 10 Devils Hole ......................................... 10 Physical features ................................ 10 Water-level fluctuations ......................... 10 Spring discharge .................................... 12 Wells and drill holes ................................. 12 Results of aquifer tests ........................... 15 Pumping records ................................ 21 Water-table configuration ............................ 22 Water quality ....................................... 24 Temperature ................................... 24 Chemistry ...................................... 24 General character ............................. 24 Lithium ...................................... 27 Boron ........................................ 27 Silica ........................................ 27 Nitrate ...................................... 27 Chemical stability of Devils Hole and King Pool . . . 27 Quality for irrigation .......................... 28 Quality for domestic use ........................ 29 Observed effects of pumping .............................. 29 Effect on Devils Hole water level ...................... 29 Impact of individual wells ........................ 32 Page Observed effects of pumping— Continued Effect on spring discharge ........................... 32 Big Spring .................................... 33 Jack Rabbit Spring ............................. 33 Point of Rocks Springs .......................... 34 Collins Spring ................................. 34 Crystal Pool ................................... 34 Five Springs area .............................. 34 Purgatory Spring .............................. 34 Longstreet Spring ............................. 35 Rogers Spring ................................ 35 Soda Spring ................................... 35 Fairbanks Spring .............................. 35 Other springs .................................. 35 Other sources of water capture ....................... 36 Effect of water-table depth ...................... 36 Definition of pumping units ...................... 36 Capture of evapotranspiration ................... 38 Recharge by infiltration ......................... 39 Overdraft of local subsystem in 1971 ................. _. 39 Source of overdraft ............................. 40 Safe yield ..................................... 40 Examination of alternative causes .................... 42 Movement of ground water in Ash Meadows area ........... 42 Nature of the regional flow system ................... 42 Flow in the local subsystem .......................... 43 Evidence from water chemistry and temperature . . . 43 Evidence from hydraulic testing .................. 45 Geologic evidence .............................. 47 Role of travertine beds ...................... 47 Structural control .......................... 47 Paths of spring discharge ........................ 48 Synthesis of flow near Devils Hole .................... 43 Development with minimum impact .................. 50 Conclusions ........................................... 51 References ............................................ 52 III IV CONTENTS ILLUSTRATIONS Page FIGURE 1. Index map showing location'of Ash Meadows area ............................................................. 2 2. Graph showing monthly lowest water levels in Devils Hole. percentage of natural rock ledge submerged, and estimated pumpage from wells in Ash Meadows, 1965 to mid-1972 ................... 3 3. Map showing topography of Ash Meadows and vicinity ......................................................... 6 4. Map showing generalized hydrogeology and boundary of the Ash Meadows ground-water system .................................................................................. 8 5. Generalized geological section along flow path approaching Ash Meadows ........................................ 10 6. Devils Hole hydrograph for July 6-14, 1971, showing fluctuations caused by earth tides and seismic events .......................................................................... 11 7. Map showing location of wells and springs in the Ash Meadows area .............................................. 13 8. Graph showing water levels and pumping histories of wells in southern Ash Meadows during March 1971 ........................................................................ 19 9. Type-curve analyses of drawdown and recovery measurements during . tests of well 1, March 1971 .............................................................................. 19 10. Map showing generalized contours of water-table altitude in the Ash Meadows area ................................ 23 11. Map showing locations of sampling points and distribution of dominant and selected minor constituents of water samples from the Ash Meadows region .................................. 25 12. Diagram showing classification of irrigation water from Ash Meadows 1 sources by conductivity and sodium-adsorption ratio ....................................................... 29 13. Graphs showing mean daily water levels in Devils Hole and observation well 17S/50-36dd and estimated pumping from wells in Ash Meadows during 1971 ............................. 30 14. Segments of the 1972 hydrograph of observation well l7S/51-31dd, showing effects of wells 1, 2, 3, and 17 ............ 31 15. Graph showing mean daily water levels in Devils Hole and approximate monthly pumpage from wells in southern Ash Meadows, late 1970 through early 1973 .................................. 32 16. Graphs showing discharge of selected springs in Ash Meadows, J anuary-October 1971 ............................. 33 17. Map showing location of the spring line and pumping units in Ash Meadows ....................................... 37 18. Sketches showing comparison of the effects on spring discharge and the water level in the regional aquifer when pumping is (A) close to and (B) remote from the spring ................................... 41 19. Schematic illustration showing concentration of flow in a carbonate aquifer from many paths of low permeability into a few highly permeable conduits .............................................. 43 20. Diagram showing percentage reacting values of dominant ions in water samples from wells and springs in Ash Meadows and vicinity ....................................................... 44 21. Graph showing transmissivities plotted against storage coefficients calculated from aquifer tests in southern Ash Meadows .............................................................. 46 22. Map showing generalized degrees of hydraulic connection among Devils Hole, production wells, and observation wells in southern Ash Meadows . . . . . . . . . . . . ._ ........................................ 47 23. Map showing lineations and possible faults in Ash Meadows and vicinity .......................................... 49 24. Sketch maps showing conceptual models of dominant and diffused flow in the vicinity of Devils Hole ................................................................................. 50 TABLE S Page TABLE 1. Major stratigraphic units in the vicinity of Ash Meadows ...................................................... 7 2. Records of springs in Ash Meadows .......................................................................... 14 3. Records of selected wells and drill holes in Ash Meadows ....................................................... 16 4. Aquifer-test data for selected wells in Ash Meadows ......................................................... 20 5. Estimated withdrawals in acre-feet from electrically pumped wells operated by Spring Meadows, Inc., in Ash Meadows, January 1969-January 1972 ........................................................ 22 6. Chemical analyses of water samples from Ash Meadows and vicinity ............................................. 26 7. Comparative analyses of samples taken at different times from Devils Hole and King Pool .......................... 28 8 . Estimated capture of water pumped from wells and overdraft from pumping units in 1971 ........................... 39 CONVERSION TABLE ENGLISH-METRIC EQUIVALENTS width of aquifer (ft 2/d) English unit Metric equivalent Length inch (in) = 25.40 millimetres (mm) inch (in) = 2.54 centimetres (cm) foot (ft) = 30.48 centimetres (cm) foot (ft) = 0.3048 metre (m) mile (mi) = 1.609 kilometres (km) Area , acre = 4.047 X 103 square metres (m2) acre = 4.047 x 10'3 square kilometre (kmz) square mile (mi2) = 2.590 square kilometres (ka) Volume gallon (gal) = 3.785 X 10‘3 cubic metre (m3) cubic foot (ft3) = 2.832 x 10-2 cubic metre (m3) acre-foot (acre-ft) = 1.234 x 103 cubic metres (m3) acre-foot (acre-ft) = 1.234 x 10'6 cubic kilometres (km3) Discharge gallon per minute (gal/ min) = 5.451 cubic metres per day (m3/d) acre-foot per day (acre-ft/d) = 1.234 X 103 cubic metres per day (ma/d) acre-foot per year (acre-ft/ yr) = 1.234 x 103 cubic metres per year (m3/yr) Tmsmissivity cubic foot per day per foot = 9.291 X 10‘2 cubic metre per day per metre width of aquifer (m 2/d) Specific Capacity gallon per minute per foot drawdown = 17.88 in well (gal min-1ft'1) cubic metres per day per metre drawdown in well (m3d'llm'1) Temperature degrees Fahrenheit = 1.8 X degrees Celsius (°C)+32° EFFECT OF IRRIGATION PUMPING ON DESERT PUPFISH HABITATS IN ASH MEADOWS, NYE COUNTY, NEVADA By W. W. DUDLEY, JR. and J. D. LARSON ABSTRACT The Ash Meadows area, at the southern tip of the Amargosa Desert in southern Nevada. discharges ground water collected over several thousand square miles of a regional flow system developed in Paleozoic carbonate rocks. Water moves westward across fault contacts from the bedrock into poorly interconnected gravel, sand, and terrestrial-limestone aquifers in the upper few hundred feet of the basin sediments at Ash Meadows. A small pool in Devils Hole, which is a collapse depression in Cambrian limestone, and numerous springs in the adjacent desert valley contain rare fish species of the genus Cypn'nodon, faunal remnants of Pleistocene lakes. The Devils Hole pupfish, C. diabolis, is the most endangered of the several surviving species that have evolved since the post-pluvial isolation of their ancestors. This population feeds and reproduces on a slightly submerged rock ledge. Recent irrigation pumping has nearly exposed this ledge. Correlation of pumping histories with the stage in Devils Hole allows identification of several wells that affect the pool level most severely. Some springs that are habitats for other species of Cypn'nodon have reduced discharge because of pumping. Hydraulic testing, long-term water-level monitoring, water quality, and geologic evidence aid in defining the principal flow paths and hydraulic interconnections in the Ash Meadows area. INTRODUCTION Devils Hole, a starkly scenic collapse depression in limestone hills in the southeastern part of the Amargosa Desert, Nye County, Nevada (fig. 1), was incorporated by Presidential Proclamation into the Death Valley National Monument in 1952. In a warm pool 50 ft (15 m) below the land surface surrounding this exposed cavern lives a unique species of desert pupfish, Cypn'nodon diabolis. The Devils Hole pupfish, less than 1 in. (about 2 cm) long, evolved from late Pleistocene ancestors left isolated in this former limestone spring when the level of the pluvial lakes of the Death Valley area receded. To the west of these hills and their alluvial apron lies Ash Meadows, a linear area of many oases and salt meadows watered by dozens of springs, several of which discharge an even flow of more than 500 gal/min (2,700 m3/d). Additional species of the genus Cyprinodon inhabit these springs and the outlet channels below them. Residents of the valley before the mid-1960’s used the natural springflow for irrigation downslope. The springs of Ash Meadows are the principal discharge points for the Ash Meadows ground-water system, shown on figure 1 to integrate the subsurface drainage from a large area of southern Nevada. The westward overflow from the Ash Meadows discharge contributes to water in the adjacent regional system, the Pahute Mesa ground- water system. In 1967 a ranching corporation, Spring Meadows, Inc.,1 began acquiring large acreages in Ash Meadows, much of it distant or upslope from the springs. The antici ated development of about 12,000 acres (about 50 km ) in crops for cattle feed, together with the need for water distant from large springs, spurred intensive development of a well field between 1967 and 1970. Coincident with the expansion of the agricultural enterprise and increasing withdrawal of water from the valley, the water level in Devils Hole began to decline in 1968 (fig. 2). As the pool receded, a slightly submerged rock ledge upon which 0. diabolis feeds and propagates began slowly to be exposed to the air. A water level of 2.2 ft (0.67 m) below an arbitrary reference point (copper washer) was defined in 1970 by the National Park Service as covering 100 percent of this shelf. The relationship of shelf coverage to water level shown in figure 2 is no longer valid, for removal of debris in 1972 has increased the area covered at a given water level. Government and private conservationists and biologists, forecasting the extinction of this endangered species, called for action by the Federal Government. In 1969, a Desert Pupfish Task Force was formed within the US. Department of the Interior; it was composed of representatives from the National Park Service, the Bureau of Land 1A subsidiary of the Farm Land Company; Spring Meadows, Inc., became Cappaert Enterprises in 1972. 2 EFFECT OF PUMPING 0N PUPFISH HABITATS IN ASH MEADOWS, NYE COUNTY, NEVADA Management, the Bureau of Reclamation, the Bureau of Sport Fisheries and Wildlife, and the Geological Survey. After reviewing initial reports by the Geological Survey (Worts, 1963; G.F. Worts, written commun., 1969) and the University of Nevada’s Desert Research Institute (G.W. Fiero and GB. |l6°30' I|6°OO' I ll5°30' “5°00“ 37°30' 37°00‘ 335$}333EEEEEEEM?:':¢UIY§§333 D'ndlon Lmhmp:Wzglzl§ffff.......z "Springs: 36 °3o' ........ (do 70 D °®X ’4 O r; MEADOWS A \ I Death Valley 0 4,6‘ PohrumpI Junction 4., L K < P r‘ Fn .< Las Vegas l I \l l 0 IO 20 30 MILES l; l I O IO 2'0 3'0 KILOMETRES FIGURE 1.—Location of Ash Meadows area. INTRODUCTION . 3 Maxey, Written commun., 1970), the Task Force directed the Geological Survey to begin a study focused on the cause or causes of the decline of the Devils Hole water level and the discharge of the springs in Ash Meadows. The investigation, resulting in this report, was financed jointly by the five member agencies of the Departmental Task Force. In August 1971 the United States filed a civil suit in the United States District Court, Las Vegas, Nev., seeking to enjoin Spring Meadows, Inc., from pumping certain wells that had known or suspected effects on Devils Hole. An agreement between the parties resulted in terminating pumping from three wells. The suit was reactivated in June 1972, and hearings in July 1972 and in April, May, and June 1973 resulted in a series of orders from the Court. These orders restricted pumping to the degree necessary to maintain the water level in Devils Hole at a stage judged sufficient for the continued survival of C. diabolis. On June 5, 1973, the Court appointed a I.2 ——o.4 '4 ,\ l" .A \ A I.6 \ 05 LB \ ., jg 2_o_ PERCENTAGE OF 70-6 4w g: SHELF COVERED g3, {12;} 0 so Ioo /\ 3; 2.2 J a: fin: . V 07 LLIEJ I—‘-'-' -—-——— 1969192 percent——— ————— ‘ ‘ I-CL 4% <0. 3(3. 2.4— 38 I—U I— 3; DEVILS HOLE)\ 3%, BS 2'5“ —08 Ed 3% ‘ 4°“ > *3 _|l- _J In: 2.8- In: I—UJ I—l‘ 5“ \ I \ g; z -O.9 2— 3.0— V kl 2% f ———————— —— I97oi46percen1 —— —————— —--—-——- \ A 3 2- \ I - 3.4— ——-— ——————— ——-— I97|=2l percent ——— ———————————— - —---— — 3‘6” /L--——— ——————— —-JUNE I972=|5percent — —————————————————— ——\ I,l 3'8 I965 I966 I967 I968 I969 I970 197I I972 YEAR PI 0 -o E1 35 NO DATA 0*; “.12 500 :02 III: Ul—D: um _|.0 uLu <0. E0. I000 I965 I966 I967 I968 I969 I970 I97I I972 ESTIMATED PUMPAGE FIGURE 2.—Monthly lowest water levels in Devils Hole, percentage of natural rock ledge submerged, and estimated pumpage from wells in Ash Meadows, 1965 to mid-1972. 4 EFFECT OF PUMPING 0N PUPFISH HABITATS IN ASH MEADOWS, NYE COUNTY, NEVADA Special Master to regulate pumping in Ash Meadows. Defendants’ appeal of the District Court decision was rejected in 1974 by the United States Court of Appeals for the Ninth Circuit (San Francisco, California). In June 1975 the United States Supreme Court agreed to review during its 1975-76 term the earlier decisions of the District and Ninth Circuit Courts in this case, entitled United States of America '0. Francis Leo Cappaert et al. Because of the decision’s conflict with state-assigned water rights, briefs supporting the ranch’s appeal to the Supreme Court were filed by Nevada and jointly by Hawaii, Idaho, Kansas, Montana, New Mexico, and Wyoming. PURPOSE, SCOPE, AND ORGANIZATION The primary objective of this investigation is to establish the degree to which controllable causes, such as local pumping, have lowered the pool level in Devils Hole and decreased the flow of springs in the Ash Meadows area. Inherent in this objective is the evaluation of possible alternative causes, such as distant pumping in the past, natural and man-made earthquakes, or climatic changes. Secondary purposes, required as intermediate steps in reaching the primary objective, are to increase the knowledge of the local hydrogeology and to understand the hydraulics of the relationship among pumping, water levels, and spring discharge. However, the hydrogeologic investigation conducted during the course of this study was limited to the collection of data required to fulfill the primary objective. It is not intended to serve as a complete hydrogeologic description of the Ash Meadows area. The basic data assembled during this study to meet these objectives are presented in the section “Hydrologic Features of Ash Meadows.” Under the heading “Observed Effects of Pumping,” these data are correlated and interpreted in terms of the primary objective. Finally, in the section “Movement of Ground Water in Ash Meadows Area,” the secondary purposes are fulfilled by an interpretation of local geologic controls on ground-water movement and by consideration of alternative development of water supplies. A companion study, requested by the Departmental Pupfish Task Force and conducted by the University of Nevada’s Center for Water Resources Research, also examines the Ash Meadows area from the standpoint of ground-water management to allow development with a minimum of environmental impact. Bateman, Mindling, Naff, and Joung (1972) have reported results of the initial year of this study. From September 1970 through October 1971, data on water levels, spring discharges and pumpage were intensively gathered by the Geological Survey. It was necessary to continue a less intensive data-collection program after October 1971 to complete records for the 1971 pumping season. The Geological Survey has continued to monitor selected observation points in order to provide basic data and interpretations for use in the continuing litigation (Larson, 1973 and 1974). LOCATION SYSTEM Township, range, and section are used throughout this report for locating features and for indexing wells and springs. Townships south and ranges east, both in increments of approximately 6 mi (9.65 km), are referenced to the Mount Diablo baseline and meridian, respectively. The term township is also used to describe an area approximately 6 mi (9.65 km) on each side, which is subdivided into 36 sections, ideally of 1 mi2 (2.59 kmz) each. Within a section, points are located according to the quarter-section (160-acre or 0.648 kmz) in which they fall. Where greater precision is needed to distinguish between closely grouped points, locations are given to the nearest 40 or 10 acres (0.162 or 0.040 km2) by further subdividing quarter-sections. As an example of the notation in standard use, the southeast quarter of the southwest quarter of the northwest quarter of section 10, township 17 south and range 50 east is abbreviated as SE 1/4. SW1/4NW1/4 Sec. 10, T. 17 S., R. 50 E. Index numbers lead with the grosser location and progress toward the more precise. The letters a, b, c, and d are applied in counterclockwise manner to the quarters, beginning in the northeast quarter. A feature located in the 10-acre (0.040-km?) square of the example above, therefore, is indexed as 17 S/50E-10bcd. Since only east ranges are referenced to the Mount Diablo meridian, the notation 17 S/50-10bcd is an acceptable abbreviation. ACKNOWLEDGMENTS Mr. B.L. Barnett, manager of the Spring Meadows Ranch, cooperated graciously in allowing access to ranch properties and by providing flumes and recorders to monitor certain springs. Unpublished lithologic, hydraulic, and chemical data were provided by Ed L. Reed and Associates, Midland, Texas. REGIONAL SETTING PHYSIOGRAPHY Ash Meadows lies within the Great Basin, a subdivision of the Basin and Range physiographic province, and is typical of this large region of the southwestern United States. Although geologically REGIONAL SETTING 5 complex in detail, the Great Basin is characterized by widespread uniformity of its geologically young structural features. Normal faults of large displacement isolate northerly-trending mountain ranges among broad, alluvium-filled valleys. Although low divides commonly occur between valleys, forming closed drainages, Ash Meadows is drained by Carson Slough, a through-flowing tributary of the Amargosa River, which terminates in Death Valley. The boundaries of Ash Meadows are poorly defined, but the name is generally applied to the gently sloping terrane, watered by numerous springs, within the southeastern part of the Amargosa Desert. The area, depicted in figure 3, lies roughly between altitudes 2,100 ft (640 m) and 2,400 ft (730 m). On the east a segmented group of low hills provides local relief ranging from about 500 ft (150 m) in the north to about 900 ft (270 m) in the central region near Devils Hole. In the southern part and to the east of Jack Rabbit Spring and Big Spring, a prominent range borders the area with relief of about 2,000 ft (600 m). The western boundary of Ash Meadows corres- ponds to the western limit of the low salt meadows in the Carson Slough bottomland. Fairbanks Spring defines the northern limit, and Bole Spring is approximately the southern limit. As thus defined, Ash Meadows lies wholly in Nevada and Within the townships T. 17 and 18 S., R. 50 E. and T. 18 S., R. 51 E. The higher slopes bordering the eastern hills are composed of dissected alluvial fans and pediments cut on older Quaternary lakebeds. Dense non-marine limestone beds, including the fossil effluent of now extinct springs, form a resistant westward-sloping planar divide in much of the interchannel area. At some locations, particularly north of Fairbanks Spring, these beds form prominent buttes. Between altitudes 2,325 ft (709 m) and 2,175 ft (663 m), dozens of springs and small seeps discharge a total of about 11,000 gal/min (60,000 m3/d), about 3,000 gal/min (16,000 m3/d) of which is from Crystal Pool (188/50-3adb) alone. Dense to moderate growths of mesquite occur at the springs and near the outlet channels below. Mixed with the mesquite, and extending farther from the channels, is a cover of saltbush, ranging from healthy to sparse. Saltgrass forms a luxurious growth where the spring channels empty into poorly drained flatlands, particularly along the flood plain of Carson Slough. CLIMATE Because the National Weather Service does not maintain weather stations in Ash Meadows, climatic parameters were extrapolated from the published records for Beatty, Lathrop Wells, and Boulder City, . Nevada, and from those for Death Valley, California. The mean annual temperature at Ash Meadows is approximately 18.5°C (65°F), as estimated from the 155°C (60°F) mean at Beatty and about 18°C (64°F) at Lathrop Wells. Annual precipitation probably averages between 3 and 4 in. (about 75 to 100 mm) and pan evaporation is probably about 100 in. (2,500 mm) per year. HYDROGEOLOGY Table 1 shows the wide variety and great thickness of rocks that occur regionally in southeastern Nevada. Upper Precambrian and Paleozoic (Cambrian through Permian) rocks are primarily marine in origin, having been deposited in widespread but shallow seas. The pressure and heat resulting from deep burial and later tectonic forces transformed the sediments into dense limestone, dolomite, argillite, and sandstone. During several tectonic episodes the Paleozoic and older rocks were folded, fractured, and thrust over each other to form now-extinct mountain ranges. Mesozoic rocks, if ever deposited in this area, were removed by erosion along with thousands of feet of Paleozoic rocks. The present topography of the Great Basin began its development in the Tertiary Period. Volcanism became widespread, and the region was broken by northerly-trending normal faults that transect older structural patterns. The landscape changed to one of narrow, abruptly rising, isolated mountain ranges and hills that shed their debris into broad basins. Depositional environments became individualized, and the resulting stratigraphy is unique in individual areas. Exposures of Tertiary rocks in the Ash Meadows area, described by Denny and Drewes (1965), are probably Oligocene and younger and are predominantly clastic sediments with lesser amounts of limestone and tuff. At and near the Nevada Test Site, north of Ash Meadows, great thicknesses of volcanic tuff and lava were deposited in Tertiary time. Consequently, the Tertiary and Quaternary Systems are described in table 1 only for the limited area of Ash Meadows. REGIONAL AQUIFER SYSTEM Figure 4 shows the distribution of rocks over an area of several thousand square miles. The Paleozoic and older rocks are subdivided into four hydrostratigraphic units, (table 1) as defined by Winograd and Thordarson (1975). The aquifers are composed predominantly of limestone and dolomite which transport water freely through fractures that have been enlarged by dissolution of the carbonate EFFECT OF PUMPING ON PUPFISH HABITATS IN ASH MEADOWS, NYE COUNTY, NEVADA I|6°20' “6° 15’ i Crystal Pool Point of I{ocks Sprlggs a, 8;"; — ”7% I I /: 66,0 3 Pr- E N . I I E; r + + + \\/ ———————————— E———° —————— ‘ (:5 x . A Big Slpr. | i o IMILE : o l 2KILOMETRES m , ' Contour interval 200fee1(61metres) ' 36° 30' 36° 25' 4 R.50E R.5lE. 3 an? 2 3+ E I 5 I (Supplemeniary contours.40 fee! orl2 petres) Bose from U. S. Geological Survey, Ash Meadows , 8:62,.‘500 FIGURE 3,—Topography of Ash Meadows and vicinity. REGIONAL SETTING TABLE 1.—Major stratigraphic units in the vicinity of Ash Meadows, Nye County, Nev. [Lithology, thickness. hydraulic characteristics, and distribution of Tertiary and Quaternary described for the limited Ash Meadows area only; adapted in art from Denny and Drewes (1965). Older units described for entire Ash Meadows ground-water basin; adapted from Winograd and Thordarson (1975). T, transmissivity. in eet squared per day] System Stratigraphic Lithology Thickness Hydraulic Distribution unit (feet) characteristics Quaternary Valley fill, Gravel, sand and mud. 1,000 : Discontinuous. linear Eastern one-third of Ash undifferentiated flows; channel and allu- local aquifers. Meadows, ad 'acent t0 vial fan deposits. Local Tranges from less than carbonate h“ 5- spring deposits 100 to 20,000 or more. (travertine.) Alluvial and ('2) lacustrine 2,000 i Aquitard; T less than 100 Throu hout western two- silt, clay and limestone; where tested. thir s of Ash Meadows. local peat and spring Interbedded beneath deposits. eastern one-third. Tertiary Undifferentiated Moderately to well indur- 2,000 i Aquitard: untested. but T Crops out in southwestern ated siltstone; lesser probably less than 100. Ash Meadows. Beneath tuff, sandstone. con- Quaternary elsewhere in glomerate and lime- Ash Meadows. stone. Siliceous where altered by thermal springs. Permmm?) and Tippipah Limestone Limestone. 3,600 Upper carbonate Limited areas to northeast .19. Pennsylvanian aquifer in Ash Meadows ground- E Tas much as 10,000. water basin. - I: I) Mississippian Eleana Formation Argillite With lesser. 8,000 i ' _ E mm... .m............... ”assist” WM... 2. and conglomerate; minor water basin. Beneath '0 limestone. younger units :3 Tless than 70. elsewhere. m . . . . . 3 Devonian DeVils Gate Limestone Limestone and dolomite; 8,000 i‘ Lower carbonate Regionally distributed .8 . minor quartZite and aquifer over Ash Meadows 5 Nevada Formation shale. undtwater basin o El S . Fractured aquifer with losest outcrops in E y ”H.185 Tas much as 100,000. S ecter Ran and i DOIOWW Solution enlargement ercury Val ey. <1 0 d , . E k , of fractures near Ash Possibly beneath .E r ov1cian are a Quartzne Meadows discharge area Tertiary in northern e , and robably where or western Ash 5 P080111!) Group areally restricted Meadows. v: 2p adient in the : Nopah Formation Limestone and dolomite. 2,000 1' wfiwidfifigfi,“ ground' ____________ '— Dunderberg Shale ' Member forms lower 200 feet. Crops out in hills bordering Bonanza King Limestone, dolomite. and 4,500 gggelfffiggngrn 2353's}. Formation minor siltstone. Meadows and ybeneath ' younger units through- Cambrian _ . out Ash Meadows Carrara Formation Limestone With minor 1,000 ground-water basin. "seems—re. ————————— v s he an ar ' 'te 1,000 Lower clastic Cro 5 out in anticl' With minor limestone. aquitard inphills east of siililiatlhceghe ' - . Ash Meadows. Forms “brisk”. QUalrtzne. sandstqne. 9.000+ T generally less than southern edge of Ash JT‘lfll‘tme lsil tstone. and minor 100. Restricts eadows ground-water W?” any on mestone. ground-water basin in Spring Moun- Stiriihlganon movement. tains. Locally crops out . ' or present beneath Precambrian Quartmte younger units elsewhere. Johnnie Formation 1As defined by Winograd and Thordarson (1975). minerals. The aquitards2 contain only minor thicknesses of soluble rocks and are composed chiefly of elastic rocks that impede the flow of ground water. Because of their geometric distribution (fig. 4), the aquitards function most importantly to restrict lateral ground-water flow, thus determining the boundaries 2An aquitard is a body of rock that has low but measurable hydraulic conductivity and. therefore, impedes the flow of ground water. Where an aquitard is in stratigraphic juxtaposition to an aquifer and retards ground-water movement from the aquifer, it functions as a confining bed. as defined by Lehman and others (1972). The more specific term. confining bed. is preferred by the Geological Survey where both the hydraulic and of the Ash Meadows ground-water system. stratigraphic conditions warrant its use. The lower elastic aquitard includes upper Precambrian and lowermost Cambrian clastic rocks that have generally low permeabilities. Above this unit is the lower carbonate aquifer, composed of about 15,000 ft (4,600 m) of limestone and dolomite, interbedded with minor thicknesses of siltstone, argillite, and shale of Cambrian, Ordovician, and Devonian age. Drill holes penetrating the lower carbonate aquifer show its transmissivity (hydraulic conductivity times thickness) to be highly variable. EFFECT OF PUMPING 0N PUPFISH HABITATS IN ASH MEADOWS, NYE COUNTY, NEVADA |I6°3o' I ||6°00' I ll5“30' l5°lOf" I NEVADA ASH MEADOWS 37°30' — 37"00I ll Ill" JACKASS “his 36°30' — @V“ ' LATHROP W ?\' é >E‘MERCURY 3 WELLS fl é : g: p 1?— ““9““ e?— “ 9““ > I I > Z > _ m 1 7 A ’37 LAMO 4 10-: I g“ t e w ( ’ _ i ' " . a I figs 9:; o I FLATS QQg/QV% g 'llllll lllTllllU/ HIIJJ—H' 1/ \ll llllllll v l I l l l I 1 l llllifl‘ITT‘rI—IIII lllllllll iI-nx IITQLI—LIJJJJJ | l QUATERNARY Alluvium, lake beds,and minor volcanic rocks TERTIARY - Lake beds and bedded tuff in Ash Meadows Tuff, rhyolite,and associated volcanic rocks MESOZOIC (Minor —- not shown ) PALEOZOIC Undifferentiated rocks above lower elastic aquitard §\\\\§ Upper clastic aquitard 5'0 MILES | 75 KILOMETRES E XPLANATION Lower carbonate aquifer PALEOZOIC (CAMBRIAN)-PRECAMBRIAN Lower clastic aquitard Contact Thrust fault Approximate boundary of Ash Meadows ground-water system Approximate direction of ground-water flow Trace of section shown in figure 5 FIGURE 4.—Generalized hydrogeology and boundary of the Ash Meadows ground-water system. Adapted from Carlson and Willden, 1968; Denny and Drewes, 1965; and Winograd and Thordarson, 1975. 7” REGIONAL SETTING 9 Where they are not fractured, these carbonate rocks have low transmissivities, but throughout the region the unit is broken by fractures and faults that often are enlarged by solution. Transmissivities of almost 100,000 ft2/d (almost 10,000 m2,/d) have been measured in U.S. Geological Survey wells penetrating only about 300 ft (approximately 100 m) of the Bonanza King and Carrara Formations at a site about 8 mi (13 km) northeast of Ash Meadows (Johnston, 1968). The rocks exposed in most of the hills on the east side of Ash Meadows, and those in which Devils Hole is formed, are of the Bonanza King Formation (Denny and Drewes, 1965). Above the lower carbonate aquifer there is an 8,000-ft (2,400-m) thickness of Mississippian and Devonian argillite interbedded with coarser elastic rocks and occasional thin limestone of the Eleana Formation. This unit, designated by Winograd and Thordarson (1975) as the upper clastic aquitard, displays transmissivities generally less than 70 ft2/d (6 m2/d), even where penetrated for several hundred feet. The Tippipah Limestone (Permian (?) and Pennsylvanian) occurs at scattered localities but has been removed by erosion over most of the area. Where present beneath the water table, however, it is highly transmissive and was defined by Winograd and Thordarson (1975) as the upper carbonate aquifer. Although no Paleozoic rocks above the lower part of the Nopah Formation (table 1) are known in Ash Meadows and the hills on its east border, Denny and Drewes (1965) identified carbonate rocks with minor interbeds of chert and clastics in the southern Funeral Mountains (between Ash Meadows and Death Valley) as probably Silurian and younger. Consequently, the rocks above the Nopah Formation in the lower carbonate aquifer, and younger units, may occur beneath the Tertiary System in Ash Meadows. The highly transmissive lower carbonate aquifer is widely distributed beneath the ranges and basins lying to the northeast of Ash Meadows. Recharge to the aquifer moves through fractures and fault zones, which form a conduit system so permeable that it acts as a gigantic drain for about 4,500 mi2 (about 12,000 km?) (Winograd and Thordarson, 1975). The flow System encompassed by this area (fig. 4) discharges at the numerous springs in Ash Meadows and is therefore known as the Ash Meadows ground-water system. Walker and Eakin (1963) estimated the natural spring discharge of the system to be about 17,000 acre-ft per year (about 21 million m3 per year). LOCAL AQUIFER SYSTEM Scattered exposures of Tertiary sediments occur near the Nevada-California State boundary in western Ash Meadows (fig. 4) (Denny and Drewes, 1965). Except for local occurrences of coarse fanglomerates, the Tertiary rocks are chiefly lacustrine in origin and composed of claystone, siltstone, and fine-grained sandstone (Denny and Drewes, 1965). Similar lithologies are expected to underlie the Quaternary valley-fill sediments beneath most of the Ash Meadows area, but they have not been recognized in drill holes, possibly because of their similarity to lower Quaternary sediments. No productive aquifers are known within the lower Cenozoic section. During pluvial periods in the Pleistocene Epoch the Death Valley region was occupied by widespread, interconnected lakes. While ancestral forms of present pupfish species spread throughout the region, sediments similar to those of the Tertiary System were deposited in the Ash Meadows basin. The lake levels fluctuated in response to long-term climatic changes, causing now-buried shoreline facies to migrate back and forth laterally. Alluvial deposits above the shoreline consisted of channel gravels and sand, mudflow debris, peat, and travertine from numerous springs. Caliche formed at several times and is commonly encountered in drill holes in the eastern part of Ash Meadows. The origin of massive beds of continental limestone in the upper Cenozoic section is not well known, but they probably resulted from redeposition of carbonate minerals dissolved from the Paleozoic rocks by ground water. While the travertine and caliche attest to the carbonate load in the ancient spring discharge, a more uniform and widespread environment is required to explain the massive limestones. Possibly the lake occupying the Ash Meadows basin became sufficiently concentrated to precipitate carbonate minerals. More likely, however, large ponds became periodically isolated above the shoreline during periods of lake recession. ' The shifting shoreline facies and varied materials deposited above the shoreline resulted in a highly complex local system of aquifers. The most productive aquifers are the channel gravels and travertine beds, but these occur in narrow linear and discontinuous patterns. Moderate production is possible from sand, but the ancient shoreline environment apparently provided only local accumulations of beach and dune sand. Where it is well fractured, the continental limestone yields water freely, but dense, unproduc— tive sections are commonly penetrated. Figure 5 shows the hydrogeologic framework of the Ash Meadows discharge area. Faults near the eastern edge of Ash Meadows have interrupted the continuity of the lower carbonate aquifer sufficiently to terminate the regional flow system. Ground water 10 EFFECT OF PUMPING 0N PUPFISH HABITATS IN ASH MEADOWS, NYE COUNTY, NEVADA ’3 < ASH §l§ MEADOWS , FEET A3“; A 4000 —°' 59""95 METRES l A . L IOOO 2000 - ll ............... f 500 SEALEVEL—Eff; I::::."" '_'_-;;;; ______ — SEALEVEL 2000 —7 -_\'/’ 5/; T """ _ 500 -\"-‘—7i " 71/41; 5 “-44-“7V /- ‘ 1000 4000 Tf/T '2‘. 7.. \ , , \ ,V; “17“,); /"'~\ ',/~_/ >35: —~_//‘-\'T .\. — 6000 —'\/-i‘?- +\ -\"—f-‘/.':'-.\ ./.—’-l-\ "/~4~.\ 739/“ V‘ ‘3“ '/'/i+/ ' ~—'—: ’71.,- '500 0 2 4 6 e lo MILES H l I I [I I I l I I o 2 4 e 8 IO l2 KlLOMETRES VERTICAL EXAGGERATION EXPLANATIO E Quaternary lake beds and alluvium Tertiary lake beds and bedded tuff Paleozoic undifferentiated moves up and westward into the complex local aquifers to discharge at the springs. Later in this report it is convenient to refer to the regional aquifer or regional flow subsystem and the local aquifers or local flow subsystem. The term “subsystem” is used to emphasize that the regional lower carbonate aquifer is the source of virtually all water discharged from the local subsystem in Ash Meadows. HYDROLOGIC FEATURES OF ASH MEADOWS [DEVILS HOLE PHYSICAL FEATURES The present configuration of Devils Hole has resulted from solution enlargement of a fault zone in the Bonanza King Formation and from subsequent collapse of the roof and walls into the cavern. The pool is oriented along the direction of strike of the fault, about N. 40° E. Beneath the water level the cavern system follows the 70° SE dip of the fault and is open to a depth of at least 300 ft (90 m), the present limit of exploration. The width of the tabular cavern opening is as much as 20 ft (6 m). Several “rooms” have been discovered both to the northeast and to the southwest along the strike (Warts, 1963). Collapse of the roof and walls has left rock rubble that partly obscures the solution opening above the pool surface. A block of limestone about 10 ft (3 m) APPROX. X 2.5 N E Paleozoic lower carbonate aquifer ‘W', Paleozoic (Cambrian) and Precambrian lower clastic aquitard Fault, arrow indicates direction of relative movement FIGURE 5.—Generalized geologic section along flow path approaching Ash Meadows. Modified from Winograd and Thordarson, 1975. opening at the southwest end of the pool, forming the floor of the shelf upon which the Devils Hole pupfish feed and reproduce. Above the pool the hanging (overhead or southeast) wall of the fault has a discontinuous crust of secondary carbonate minerals where the continued sloughing of rock fragments has not exposed fresh rock. This coating is particularly well preserved at the entrance to Devils Hole, about 30 ft (9 m) above the pool surface. The walls of the cavern opening beneath the water are almost continuously encrusted. Several formerly sustained pool levels above the present stage are marked by horizontal depositional rings of calcite or dolomite. On the walls of a small room isolated by a “keystone” block at the northeast end of the pool a travertine ledge about a foot wide marks the pre-1969 sustained level of about 1.2 ft (0.37 m) below the copper washer used as the water-level reference. WATER-LEVEL FLUCTUATIONS The Geological Surveyhas recorded the water level in Devils Hole intermittently since 1956, but the record prior to 1962 is discontinuous. A copper washer was placed on the cavern wall in 1962 as a reference for water-level measurements. With respect to this reference, records prior to 1962 may be in error by about 0.3 ft (9 cm). Between 1962 and 1968, however, wide and at least 20 ft (6 m) long is wedged into the the water level (fig. 2) was very stable. The seasonal HYDROLOGIC FEATURES OF ASH MEADOWS 11 changes of mean daily levels (about 0.2 ft or 6 cm) were small compared with the monthly changes of water level, which ranged from 0.3 to 0.5 ft (9 to 15 cm). Daily fluctuations were frequently as great as the monthly differences. The stage of the pool in Devils Hole fluctuates in response to several stimuli. Constant variation of the tidal forces exerted on the Earth’s crust by the Moon, and to a lesser degree by the Sun, cause elastic deformation of the carbonate aquifer, resulting in continuous changes in its storage volume. Figure 6 shows the cyclic changes in water level that result from the tidal forces. The strongest of the several components of the tidal forces has a periodicity of approximately 1 day and causes the large diurnal change of water level. Superimposed on this is a semi-diurnal change that gradually modifies the shape of the daily hydrograph. The pattern of reinforcement and interference of various tidal components results in a peak daily amplitude about every 2 weeks, followed by gradually diminishing amplitudes for about 1 week and then increasing during the second week to a new maximum amplitude. The biweekly maxima of daily amplitudes are generally between 0.3 ft (9 cm) and 0.4 ft (12 cm). Daily mean levels tend to be about 0.2 ft (6 cm) to 0.25 ft (7.6 cm) above the daily low. Changes in barometric pressure affect the' water level in Devils Hole to a lesser degree. A barometric high may suppress the stage by as much as 0.1 ft (3 cm), while a low may increase it by a similar amount. Superposition of this irregular stimulus on the cyclic tidal changes causes day-to-day changes in the mean daily level of as much as 0.2 ft (6 cm). This natural variabiltiy has hindered short-term definition of the pool level which, in turn, has prevented precise regulation of the level by modifying pumping schedules. Nuclear explosion ”Miniata” 46 mi (74 km) NNE M = 5.3 Earthquake central Chile 5,500 mi (8,850 km) SSE M = 7.5 Short-term fluctuations of the water level result commonly from high winds, which cause local changes of air pressure at the pool surface. The hydrograph trace is frequently “noisy” because of winds. Seismic events, including natural earthquakes and nuclear explosions at the Nevada Test Site north of Ash Meadows, cause cyclic, short-term fluctuations of the water level in Devils Hole. Figure 6 shows three responses that are typical of most in the record. The Miniata nuclear explosion generated a response having a total amplitude of about 0.1 ft (3 cm). Both of the earthquakes recorded on the hydrograph produced responses that were greater in amplitude and in duration. The water level continued to oscillate for about an hour after the initial reaction to the Chilean earthquake. About 2 hours of oscillation followed the New Ireland earthquake. Cooper, Bredehoeft, Papadopulos, and Bennett (1965) have explained the relationship between seismically induced changes in the fluid pressure in aquifers and the water-level response in a well. The geometry of Devils Hole is such that its reaction is similar to that of a well. As in response to variations in earth tides, the magnitude of the imposed stresses and the mechanical properties of the aquifer are the first of several parameters affecting the water-level reaction. Because the seismic stresses change rapidly and time is required to move water in and out of the “well”, however, the hydraulic properties of the aquifer and the geometry of the “well" also influence hydroseismic response. The interaction of the hydraulic and geometric factors with the frequency of the seismic waves results in- varying ratios of change in water level to change in aquifer fluid pressure, according to Cooper, Bredehoeft, Papadopulos, and Bennett (1965). For seismic waves having short periods (high frequency) this amplification factor is less than unity. For very long-period stimuli, such as earth tides, the Earthquake New lreland region 6,900 mi (11,000 km) WSW M = 7.8 27 I 2. n \l - 0.85 ,m /\ /\\ / ‘ /\ r/‘0'90 \/ \/ \n VVVV DEPTH TO WATER, lN FEET BELOW COPPER WASHER v V U -0.95 DEPTH TO WATER, IN METRES BELOW COPPER WASHER 3.2 6 7 8 9 JULY 11 12 13 14 FIGURE 6.—Devils Hole hydrograph for July 6—14. 1971, showing fluctuations caused by earth tides and seismic event. (M is the Richter magnitude of seismic event, as reported by the US. Department of Commerce. National Earthquake Information Center.) 12 EFFECT OF PUMPING ON PUPFISH HABITATS IN ASH MEADOWS, NYE COUNTY, NEVADA water-level change is the same as the pressure change, or the amplification factor is 1. Certain wave periods, however, combine with the hydraulic and geometric parameters to produce resonance, resulting in an amplification factor greater than 1. The test wells 8 mi (13 km) northeast of Devils Hole respond most efficiently to wave periods of about 30 seconds. The sustained and relatively large reactions of Devils Hole to the distant earthquakes shown on figure 6 suggest that the many factors combined to produce resonance in the system. On several occasions the response of Devils Hole has been sufficiently great to dislodge the float on the U.S. Geological Survey recorder monitoring the water level. The Alaskan earthquake on July 30, 1972, and the Mexican earth- quake on January 30, 1973, both dislodged the float, causing gaps in the hydrograph. Figure 6 illustrates that no permanent change in the Devils Hole water level resulted from the ‘ hydroseismic responses. Examination of hundreds of responses on the long-term hydrograph shows the lack of permanent effects. SPRING DISCHARGE The large springs of Ash Meadows, in addition to their value as pupfish habitats and an economic resource, have long been of interest to hydrologists. The origin of the discharge and controls upon the locations of the springs have been discussed by Hunt and Robinson (1960), Loeltz (1960), Winograd (1962, 1963, 1971), Walker and Eakin (1963), Hughes (1966), and Winograd and Thordarson (1975). It is the concensus of these authors that the regional lower carbonate aquifer transports most of the spring discharge to Ash Meadows from beyond the boundaries of the topographic drainage basin. The topographic setting of the major springs in Ash Meadows is shown in figure 3. Their relationship to outcrops of the Paleozoic carbonate rocks is presented in figure 7. With the exception of the Davis Springs and nearby springs in sections 11 and 12 of T. 18 S., R. 50 E., the springs fall into a northern group around the upper Carson Slough drainage, a central group in the vicinity of Devils Hole, and a southern group at and south of the Point of Rocks area (fig. 7). Table 2, based on data from Walker and Eakin (1963) and supplemented during the present study, lists the springs yielding most of the water discharged in Ash Meadows. The reported measurements show considerable variability; the contrast between early reported flows and those measured by the Geological Survey after 1950 is particularly apparent. Some of the apparent variability of spring flows may result from slight differences in measurement technique or instruments and in choice of metering locations. The smaller springs, in addition, are quite sensitive to changes in the condition of the orifice by cave-ins, trampling by stock, or cleaning of the orifice. Examination of table 2 was done, with particular reliance on Geological Survey measurements made during 1953 and 1962, to determine the typical discharge of each spring. Addition of these flows reveals a probable total spring flow of about 10,700 gal/min (58,300 m3/d) for Ash Meadows before development of ground water by wells. Of this total discharge about 35 percent occurs in the northern group of springs. The central group, dominated by the 2,900 gal/min (15,800 m3/d) flow of Crystal Pool, accounts for about 28 percent, and about 30 percent is discharged at Point of Rocks and from the springs to the south. The remaining 7 percent represents flow from Davis Springs and the numerous small seeps between Crystal Pool and Point of Rocks area. Some of this scattered minor discharge may represent secondary emergence of the flow from other springs that infiltrated to shallow aquifers in the local subsystem. The discharges of the major springs are uniform throughout the year under natural conditions. Consequently the average natural spring flow of approximately 10,700 gal/min (58,000 m3/d) yields about 17,000 acre-ft (21 million m3) annually, which agrees with the conclusion of Walker and Eakin (1963). WELLS AND DRILL HOLES Since 1961 about 40 holes reportedly have been drilled in the Ash Meadows area. Figure 7 shows the locations of the Spring Meadows production wells and certain other wells and drill holes that are of special interest. Drillers’ logs filed with the Office of the State Engineer, Carson City, Nev., and an unpublished report by Ed L. Reed and Associates (written commun., 1967) were used to compile table 3. Although most of the wells are between 200 ft (60m) and 700 ft (215 m) deep, two holes (18S/50-11dd and 18S/50-12db) were drilled to about 1,000 ft (305 m) without encountering productive zones. The “Re- marks” column in table 3 reveals that most of the productive wells penetrate travertine or continental limestones of the local aquifer system. Only five drill holes (17S/50-14cac; 17S/50-23bbl; 17S/50-23bb2, also called well 7; 18S/51-7bdb, also called well 13; and 188/51-7dbl) penetrated Paleozoic rocks. Well 7 is the only one of these that produces significant discharge. Although well 13 is only about 1,000 ft (305 m) west of an outcrop of Paleozoic rocks, these rocks were penetrated at a depth of 815 ft (248 m). —_— 13 HYDROLOGIC FEATURES OF ASH MEADOWS V Fairbanks ) Spring.“ Sodo __ . , Em“? /’ EXPLANATION 1 5'0“” 40 Production well ‘ |‘30 Olher well Rogers Spring "40°66 Flowing well U‘" Spring 6l4coc V Longslreel ll/A Paleozoic Oulcrop Springw 3 7 '. Cold M ‘ iSpring r’. L“ ("Sh I U 3 2 (n C O .‘1’ 8 :1 5 School ftp / T.l7S Spring ; T. l8 S - 36 DEVILS HOLE i 1 Crystal . P°°‘ Collins 3 Spring‘ /" °9 Davis ” Springs 4 7de Jock Robbil Spring 0 l ZMILES l l 4 l7 l I , o l 2 KlLOMETRES “j m- o _ LO In of tr.“ ”Big Spring FIGURE 7.-—Location of wells and springs in the Ash Meadows area. 14 TABLE 2.—Recards of springs in Ash Meadows, Nye County, Nev. [Data before 1963 from Walker and Eakin (1963). Data below dashed lines collected by the authors. Method and, where indicated, date unknown for data from Ed L. Reed and Associates (written commun.. 1967). QTs, quarternary and (or) Tertiary alluvial EFFECT OF PUMPING 0N PUPFISH HABITATS IN ASH MEADOWS, NYE COUNTY, NEVADA TABLE 2.—Reco7'ds of springs in Ash Meadows, Nye County, Nev. —Continued and lake sediments; aquifers are gravel, sand. travertine. or “fresh-water limestone.” QTst, travertine or “fresh-water Iimesto stone or dolomite; CM, Price current me current-meter measurements in channel Standard Pal-shall Flume with throat size 18-inch Cipolletti weir; Vol, volumetric me RW. rectangular weir. m, measured by th Cs. specific conductance in micromhos pe ne" outcrops at spring. ch, Paleozoic lime- ter in outlet channel; CM/CM, difference of below and above spring flow entry; PF(6). in inches; VW90, 90° V-notch weir; CW18. asurement with stopwatch: Obs. observed; e US. Geological Survey; others reported. r centimetre at 25° Celsius] Location Water- Method of index bearing measure- Flow Temp 1 and name unit ment (gal/min) (°C) (°F) Date Remarks « 17S/50-9ad QTst . . . . . . 1910 Fairbanks . . . . . . 7/ 14/23 . . . . . . 8/16/46 28 82 2/1/53 . . . . . h 6/7/61 27 81 7/23/62 Cs=650 (2) High flow. 82 10/ 70.12/ 71 (2) Low flow. 178/ 50~10bcd QTs ........... m85 22 72 2/ 1/ 53 Soda ........... 87 . . . 6/7/61 ........... m79 23 73 7/31/62 Cs=725 m65 5/21/71 High flow. PF2 22 72 10/70-8/71 m0 23 73 (3) Low flow. 175/ Reed 50-14cac ch Obs 50 9/1/66 (1967). Flowing well m28 (2) High flow. (“Purga- gory VW90 34.5 94 2/71-12/71 ring,” 2 SBSFW) m9 ( ) Low flow. 17S/50~15ab QTst ........... 675 . . . 12/24/23 Rogers ........... m715 29 84 12/1/53 ........... 665 . . . 6/7/61 ........... m735 28 82 7/ 29/62 Cs= m590 28.5 83 2/21/71 m570 28.5 83 2/24/ 71 Well 8 PF6 pumped 2 ays. m590 3/15/71 17s ”@2186 QTs Obs 80 9/1/66 Reed (1967). Cold —————— — —- — — —————————— PFS m73 19.5 67 (2) Stable flow 10/70- 4/71. 175/ 50-22aba QTst ........... 1,260 , . , 3/27/21 Longstreet ........... "11,240 23 5 80 2/3/53 ----------- .270 . . . 6/?/61 ----------- m1,040 28 82 7/29/62 Cs=640 Repomd 1.250 28 82 1 Reed (1967). P179 m1.040 . . . 10/22/70 CM m1,030 27 81 11/6/70 "11,110 . . . 11/23/70 m940 . . . 4/2/71 m1,040 . . . 4/15/71 m1,130 27 81 5/20/71 PF9 m1.070 . . . 7/15/71 m940 m 82 9/9/71 m1,060 . . . 10/8/71 "11,130 10/16/71 m995 11/1/71 111980 11/20/71 17S/5Q-22ac QTs Reported 155 . 1965 Reed (1967). Mchhvary . Obs m0 9/ M/70 Water level ft below outlet. No flow in 1971. Location Water- Method of index bearing measure Flow Temg and name unit ment (gal/min) (C°) ( °) Date Remarks1 l7S/50-23b1 QTS ------------ m115 34.5 94 2/3/53 ----------- m195 34.5 94 7/23/62 Cs=650 Same as 23be and (or) 23bb2 below? 178/ 50-23be QTs m75 (3) High of record. Unnamed PF3 34.5 94 10/70-9/71 (at Five m0 (3) Low of Springs record. area) Well7on. 178/ 50-23be QTs Vol m60 32 90 2/17/71 Unnamed m0 2/17/71 Well7on. (atFive Springs area) 17S/50-23b QTs Vol 17135 2/ 16/71 Combined Unnamed flow (8 seeps at Five Springs) 17S/50-35a1 QTs ........... m90 33 91 2/3/53 Twosprin s Scruggs? combin 'I ........... m140 33.5 92 7/24/62 Cs=640 17S/ 50-35acc QTs PF3 m60 33 91 (2) Northern of Scruggs two ori- fices. Steady flow recorded 11/70-2/ 71 178/ 50-35b1 QTs ........... m17 28.5 83 7/23/62 Cs=620 Unnamed 17S/ 50-35d1 QTs ........... m25 32 90 1/31/53 School ........... m6 34.5 94 7/24/62 Cs=620 185/ 50-3ldb QTst 4/1/59 C stal 89 1/31/53 001 6/7/61 91 7/29/62 Cs=650 3/3/67 Reed (1967) 2mm High of record. 10/70-11/71 9/1/71 Low of record. 188/50-1ca QTs mlO (2) Highof Collins record, VW90 (2) 25.5 78 2/71-12/71 m5 (2) Lowof record. (Sept. 1971). 18S/5o-11d1 QTs ........... m720 23.5 74 2/2/53 avis ........... m395 25 77 7/25/62 Cs=750 185/50-11d2 QTs ........... m175 23.5 74 2/2/53 Davis ........... m5 . . 7/25/62 18S/50~11d3 0T5 ........... m38 21 70 2/2/53 Davis ........... 11130 22 72 7/25/62 185/50-12c1 QTs ........... m52 23 73 2/2/53 ........... mll 26.5 80 7/25/62 Cs=725 HYDROLOGIC FEATURES OF ASH MEADOWS TABLE 2,—Records of spring in Ash Meadows, Nye County, Nev. —Continued Location Water- Method of index bearing measure- Flow Temg‘ and name unit ment (gal/min) (0°) ( °) Date Remarks1 l8S/50-12dc QTs Obs 25 9/ 1/66 Reed (1967). Sink ————————————————————— Obs m0 3/2/71 Water level 8 it below outlet. No flow in 1911. 188/ 51-7dbb QTst 7/17/43 King Pool 1/ 31/ 58 6/7/61 7/25/62 Cs=675 (7) Reed (1967). 10/275 11.}? :t— ' m1,250 11/6/70 orifice. m1.230 11/23/70 CM/CM m1,360 12/8/70 m1,160 12/29/70 ml.280 1/ 12/ 71 lBS/51—7d2 QTst ........... 135 . . . . . . 3/31/50 Indian Rock ........... m69 32 90 1/31/53 ........... 120 ... ... 6/7/61 ........... m22 33.5 92 7/25/62 Cs=640 188/51»7d3 QTs ........... m345 32 90 1/31/53 ........... 300 . . . . . . 6/7/61 ........... m380 33 91 7/26/62 Cs=645 18S/51-7d4 QTs ........... m19 84 93 7 /26 /62 Cs=650 188/51-7d5 QTs ........... m2 34 93 7/26/62 cs=650 188/51-7dba QTs, ........... m420 32 90 7/27/62 Total of 7d2. Point of ch, 34 93 7d3, 7 d4, Rocks. and and 7115, Indian QTst ————————————————————— “091% m385 5/17/71 High of Indian record. 59995 PF6 (3) 32 90 10/70-9/71 + 34 93 PF6 m290 ‘ 8/10/71 Low of record. Total of 2 flumes. 188/51-18bc QTst ........... msoo ' 28 82 2/1/53 Jack Rabbit 340 6/7/61 m585 7/27/62 Cs=675 600 (7) Reed (1967). m425 5/11/71 High of 3 record. PF6 ( ) 26 79 10/70-12/71 m0 (3) bow of record. 188/51-19ac QTst u ........... 1.120 - - 1916 fig; , m1,060 28.5 83 2/2/53 (Deep; 080 ~ - ~ 6/7/61 Ash 7/19/62 Meadows) - - » 7/26/62 83 8/27/62 Cs=700 (2) High of record. 83 1/71-10/71 (2) Low of ‘ record. 185/51-29b1 QTs ........... m1 n 72 7/%/62 Cs=790 Unnamed 188/51-30ab QTs ........... m12 a 72 7/27/62 Bole 188/51-30d1 QTs ........... m1 Z) 68 7/28/62 Cs=575 Last Chance 1Highs and lows of record determined from continuous records over period indicated. Discharge steady or changes gradually; high or low flow occurs for sustained pe 'ods. Ems/charge variable and responsive to pumping or other causes; high or low occurs commonly uring period of record. 15 RESULTS OF AQUIFER TESTS Aquifer tests of the production wells, some adequately controlled and some made during normal ranch operations, were conducted during February, March, and April 1971. Several of the wells were examined during more than one cycle of drawdown and recovery, particularly in southern Ash Meadows, where interference from other wells nearby (fig. 8) required constant surveillance from the field party in order to reconstruct usable data. Additional tests conducted during 1967 by E.L. Reed, a consultant to the ranch, were analyzed by Reed (written commun., 1967) and by RH. Johnston of the Geological Survey (written commun., 1967). Drawdown measurements (the difference between depths to water before and during pumping) in the 1971 tests were hampered in many of the pumped wells by water cascading down the casing from shallow aquifers intersected above the pumping levels. The use of float switches and shields on electrical probes aided in measuring pumping levels but the aeration and mixture with oil from pump columns resulted in a foamy mixture of water, air, and oil in several wells. Calculations of specific capacities (well yield, in gallons per minute, per foot of drawdown) were affected, for drawdowns in these shallow aquifers should not be computed from the pumping levels in the wells, but rather from the depths at which the cascading water enters the wells. Because the relative contributions of these zones are not known, all hydraulic parameters computed from drawdowns in wells that had cascading inflow are inaccurate to some degree. Type curves compiled by Lohman (1972) from several sources were used to relate the time- drawdown data to transmissivities and storage coefficients. The data were matched most successfully to curves prepared by Lohman from Boulton’s (1963) equation which describes ground-water flow when the yield from storage in the aquifer is delayed. Figure 9 shows time-drawdown data from three wells observed during testing of well 1 and the matches of these data to delayed-yield type curves. Although the matches are satisfactory, the wide range of calculated transmissivities suggests that analyses based on radial-flow equations are not widely applicable to wells in Ash Meadows. Rather, they reflect the inhomogeneity and complexity of the local aquifers. Table 4 summarizes the observations during the pumping tests and hydraulic parameters calculated from the drawdown data. Note that wells 1, 2, 3, 6, 7, and 8 were observed to lessen the discharge of one or more springs. The rapid effect of well 2 on Jack Rabbit 16 [Includes wells or holes drilled before June 1971. and selected, significant data after in addition to this study, . Nevada, by (written commun., 1967). e. estimat generally accurate to +5 feet. Leaders ( measured by the Geological Survey; minute, if known); p, well not pumping at time of In June 1971. Sources. Engineer, Carson Cit not applicable. m, EFFECT OF PUMPING ON PUPFISH HABITATS IN ASH MEADOWS, NYE COUNTY, NEVADA TABLE 3.—Records of selected wells and drill holes in Ash Meadows, Nye County, Nev. September 1970. and Ed ed are drillers’ l flled with the State h d Reefraxlig Associates rom top ap ic map an (or 1e ins ection. ....... 0%? indicate no information was able or f, flows (discharge in gallons per easurement, but is or might be 1972; 8, stock watering; guotes are from driller’ ssociates (written commun., 1967) affected by earlier pumping or driller‘s log and may not be stat eological SurfJ ey maintained water-level rec s log; othe , use abandoned or suspended rs are from sample l pumping of other wells: w, 1c level. C. commercial. excluding agricultural irrigation; order on well in 1971 and (or) n 1971 or before. Lithologies in i “first water.” as reported on studies by Ed L. Reed and Casing Water level4 Production5 Well Land- Perfor- Below . Remarks. lithology number Owner and Date surface Depth ated land Yleld Draw- Tempera- Status .and Wm?” and owner's1 completed altitu e Deptl‘}i Diameter range zone surface Date (gal/ down ture Date or Identification 2 location number (MoYr) (feet) (feet) (inches) (feet) (feet) (feet) (Mo-Yr) minl (feet) (°C/°F) (Mo-Yr) use (depth ranges m feet 1 1.78/49 G. Swink 1966 e2190 703 14-1/2 0460 38-436 3 07-66 U “Limestone" [travertine'I], 3dd 0-14. Mainly “clay with limestone" and “clayey sand and gravel." 178/50 G.C. Hanks 1263 92260 400 12-3/4 0-400 200-390 WES 1263 Ir.D “Sand” and “gravel." 85— 6cd 95, water-bearing dur- ing drilling. Production from “limestone," 287- 290. 327-340. 374-392. 17S/50 Nye 01.67 e2265 278 14 0.144 12-278 W3 01-67 lr.U Aquifers are “crevice" in 9dd County 12 134-278 limestone (92 feet) and gnawed gave] and sand." 225- 11) 17S/50 Spring 06-68 e2270 157 6-5/8 0-157 7-157 f(15) 06-68 22/72 06-68 lr,0bs “Sand and gravel." 0-20. 10cda Meadows, m6 02-71 . , . . . . . . Production from “hard. nc. mf(10) 10’“ porous lime." 112-157. Well deepened to un- known depth in 1971. 178/50 Spring 1968 e2260 . . . . . . . . . . _ . , . . . . . , . _ , . 4 Aquifers not identified. IOcdd ideadgws. m3 02-71 m900 > 140 21/70 02.71 Ir nc.. m1 04-71 .... .... .... (_,. Water cascades from 56 feet when pumping. Chemical sample. table 6. Pumping test. table 4. l7S/50 Spring 06-68 82360 92 6-5/8 0-92 0-92 f(70 06-68 . . . . . . . . Ir.U Aquifer is “fractured dolo- 14cac Meadows, f(m20 1970- 34/93 1970- mite" (Paleozoic), 25-92. 100- ‘0 m8)p 1972 1972 Drilled on travertine spring mound. Deve- loped as pupfish refuge and named “Purgatory Spring" in 1972. 178/50 Nye 03-62 62310 497 16 0-186 0-480 f(25) 03-6? 150 03-62 Ir.U Aquifers are “limestone." 15m gougt 175-480 N <5) 1971 . . , 19.5/67 1971 040; 100 feet “sand and an . l," 125-405. (Reed 2) 2250 700 14 46 640 12 03 67 U grave 9 0-641 - - . . .. 175/50 G. Swink 04-66 15 08-66 150 (1:638 08-66 A“;;§:§£.;°Eg‘ffv“;‘ffg 16” (Reed 4’ ”5) sand." 50-65; “hard lime," 172-184; “sand and lime." 309-847. 173/ 50 G. Swink 06-66 (32255 602 14 0-502 60-497 12 06-66 , . , . . . . . . . . . . . . . Ir.U Aquifers not identified. 16dd (Reed 5) 10 492-602 15 03-67 137 >164 18/64 03-67 178/50 Nye 02-67 e2210 558 14 0280 28-558 w7 01-67 . . . . . . . . . . . . . . . . U No productive aquifers. l7dd Count 12 270-558 11 03-67 110 209 19.5/67 03-67 Chemical sample. table Land . (1 hr) 6. Pumping test, table 4. (Reed 12) 17156:: D.aG. Tren- 03-64 e2185 100 14 0-100 15-100 15 03-64 “cool" 03-64 Ir,D Aquifer is “fine sand to ry coarse gravel," 84-95. 17S/50 Spring 04-70 e2240 500 16 0-500 99-500 22 04-70 500 143 "cold" 04-70 U 21aal Meadows, Inc. 175/50 Spring 05-71 e2240 500 16 0-300 0-300 m17 0571 < 300 >200 19.5/67 0571 U Water cascaded from 180 2111112 Meadows. feet during test. Water Inc. carried sand. 1178/50 Spring 05-68 e2240? 202 6-5/8 0-202 0-202 8 06-68 ? Probably 17S/50-210a, 2 lac? Meadows, Inc. See footnotes at end of table. providing small domestic supply 0 poor quality. f HYDR OLOGIC FEATURES OF ASH MEADOWS 17 TABLE 3.—Records of selected wells and drill holes in Ash Meadows, Nye County, Nevada Casing Water level4 Production5 Well Land- Perfor- Below . Remarks. lithology number Owner 8.1“! Date surface Depth ated land Y181d Draw- Tempera- Status find aquifer and owner i completed altitu Dept?i Diameter range zone surface Date (381/ down. ture Date or Identification 2 location number (Mo-Yr) (feet) (feet) (inches) (feet) (feet) (feet) (Mo-Yr) min} (feet) (°C/°F) (Mo-Yr) use (depth ranges m feet I . _ 202 6-5 , 7_ 6-68 24.5/76 06-68 U Log shows “hard porous 172(3), Spfiggdows' 06 68 e2210 /8 0 202 202 5 0 lime," 055' 85-202. Inc. 178/50 Spring 06-68 e2345 90 6-5/8 0-90 0-90 1 06-68 Ir-D. Aquifer is “fractured dolo- 23be Meadows. 1 02—71 U nute (Paleozoxc), 50-90. f‘Hard. porous lime." 0-12. is probably traver- tine. 17S/50 Spring 07-70 (92345 140 14 0-100 0-100 {(30) 07-70 500 90 . . , . 07-70 Ir 10 feet west of 23be. 23be Meadows. [(20) 02-71 m530 "140 34.5/94 02-71 Penetrates Paleozoic Inc.. 7 “black limestone." 48- 140. Chemical sample. table 6. Pumping test. table 4. 178/50 Spring 06-68 (22180 200 none U Test hole only "hard lime." 28ca Meadows, 24-28; rest is “peat." 20— Inc. 24. and clay. 173/50 Nye 01—62 2171 530 16 0-514 150-500 9 01-62 2,000 91 .. 01-62 Ir “First water in fractured 293d County m471 w22 11-61 . . . . . . . . _ , . . . . . , lime at 22 feet,“ Aqui- (Reed 1) mf(5) 06—62 - - - - - - - 19.5/67 06452 fers are “sand" or “sand Spring 12 03-67 1.375 136 19.5/6‘7 03-67 and gravel." 245.250‘ MeadWS- ‘10 “'5’ 280-320. 338-342. 415- Inc., 10 490; “fractured lime." 140-200. Chemical sam- ple. table 6. Pumping test, table 4. 175/50 Nye 10-66 2405 248 16 0-248 48-248 48 03-67 900 39 335/92 03.57 ’ Ir.U 900 feet east of Devils 36dd County mp51 ‘09-71 _ , _ , ‘ , . , _ _ . , _ _ , Hole. Aquifer is gravel. Land Co. m50 02-72 100-248: possibly also “lime." 6-100. [traver- tine?]. Chemical sample. table 6. Pumping test. table 4. 178/51 Spring 2418 12 0‘ - --'- ---- I . No lo on record 9/70. Obs 31dd Meadows. "163 02‘72 "'47 25.5/78 03-71 (31: in 81972. Affected by Inc. mp65 06372 ‘ - ' ~ . . . . pumfiin 1V: milesw the sout . hemical sample. table 6. . 188/50 U.S. 09-70 e2320 > 252 51 09-70 40 103 09-70 See No log on record 9/7o_ 2aa Bureau . . . 4 . . . , (2hr) re- Pumped to supplement °f Land 60 >198 09'70 marks flow of u fish sanctu- Manage- (1'1/2 ry at 8: col Spring ment hr) (l7S/50-35dl). 182/50 Nyéa 03-66 e2205 516 14 “0-516 0-516 “37) 03-66 1,000 130 31.5/89 03-66 Ir.U “White lime" and “sticky aa nggtéo lime" for entire depth. (Reed 3)' "1900 (3hr) Tools dropped several times during drilling. 220 . . Spring ["1370 > 120 31'5/89 04 71 Owner . said mud ap- Meadows. hr) peared in Crystal Pool. Inc. 08-71 Water cascades from ' ' " about 50 feet. Chemical sample. table 6. Pump- ing test. table 4. 188/50 Nye 08-66 2140 670 14 0.570 60-530 f(5) 08-66 ,... .._. .... .... U Welded cnP~ Chemical 58a Count f(5) 03-67 200 225 23.5/74 03-67 sample. table 6. Pump— Land 0. ing test. table 4. (Reed 7) ' 135/50 Spring e2240 . . . , . , . . S No log on record. 9/70. 11“ Meadows. mp21 02-71 Pumps intermittently to Inc.. 9 pressure tank. 188/50 Nye 10-66 e2240 960 14 0-852 210-840 , . , . . , . , . . . . , . , . . . . . . . . . U Clay and marl in upper300 11dd Counté0 f( 15) 02-67 190 > 433 30.5/87 02-57 feet; clayey and cement- Land . (1 1/2 hr) ed sand and gravel. 800- (Reed 8) 700. Chemical sample. table 6. Pumping test. table 4. 188/50 Spring 1971 92270 1.000 t 16 0- f 02-71 U Abandoned in 1971. 12db Meadows. m12 03-71 Inc. 188/50 Ash 06-65 2200 267 12 0-50 80-267 6 06-65 24 >85 06-65 8-5/8 casing cemented to 2511b Meadows 8-5/8 0-120 50 feet. Lodge 6-5/8 0-267 18 EFFECT OF PUMPING ON PUPFISH HABITATS IN ASH MEADOWS, NYE COUNTY, NEVADA TABLE 3.—Records of selected wells and dnll holes at Ash Meadows, Nye County, Nevada—Continued Casing Water level“ Production5 Well 0 d Land- Perfor- Below Remarks. lithology number wner an Date surface Depth ated land Yield Draw- Tempera- Status and 3911”" and owner-$1 completed altitu e Deptg Diameter range zone surface Date (gal/ down ture Date or identification location number (MoYr) (feet) (feet) (inches) (feet) (feet) (feet) (Mo-Yr) min) (feet) (°C/°F) (Mo-Yr) use (depth ranges in feetZ) 188/51 Spring 1970 e2435 12 0- 0- . . . . r . . . . . . . , . _ . .. .. Ir.U No log on record 9/70- 6aal Meadows 76 05-70 m60 25,5/78 01-71 Pump removed in 1971. Inc., 12 ' mp81 03-71 .,., .... .... m76 05-71 188/51 Spring 1970 e2450 12 0- 0- 95 05-70 m57 25.5/78 01-71 Ir.U D0. 6a Meadows. mp9? 0371 r. V . .. . . . , .. Inc. 11 m95 05-71 188/51 Spring 02-70 2320 500 16 0-500 139-500 24 20-70 1,500 75 . . . , 02—70 Ir.U Water cascades. Aquifer 7bbb Meadows. m25 03-71 > 1,600 110 i 30.5/87 03—71 not identified. but log Inc., 5 shows “limestone." 155- 210. 235-290; “gravel." 405-460; rest is clay. Chemical sample. table 6. Pumping test. table 4. 188/51 Nye 1966 62340 818 14 0-468 132-467 f(20) 1966 . . . . ..... . . . . . , , . Ir Collapsed below casing. 7bdb Count 43 05-70 285 253 31.5/89 08-67 Paleozoic limestone at Land 0. (3 hr) 815 feet. Water in (Reed 9) 98 07-70 “white lime" at 35 feet 112 09-70 . . . , . , . . . . . . durin drilling. Chemical S ring m2? 03-71 6200 31-5/39 03"“ samp e, table 6. Pump- Nileadows. . . . . - - . . - - ~ ~ ing test. table 4. Inc., 13 188/51 Spring 08-69 82295 500 16 0-500 100-500 6 08-69 1.200 . , , . . . . . 08-69 Ir.U No aquifer identified. Wa- 7ca Meadows. mll 03-71 m900 180 30.5/87 03-71 ter cascades from 100 Inc., 4 feet. Log shows “lime- stone" 92-230. 268-290. 320-370; “ avel." 370- 385; “san stone." 385- 470. Chemical sample. table 6. Pumping test. table 4. 188/51 Spring ,07-69 (22320 395 16 0-395 155-395 15 07-69 . . . . . . . . . . . . . . . , Ir Probable aquifers are 7daa Meadows, mp10 03-71 m1.600 m50 28/82 03-71 “brown limestone." 170- Inc.. 1 178; “broken brown lime." 225-350. Chemical sample. table 6. Pump- ing test. table 4. 188/51 Spring 05-69 92315 300 16 0-300 60-300 16 05-69 . . . . . . . . . . . . . . . . Ir Probably aquifers are “cal- 7dac Meadows. m8 03-71 m1.200 70 I 26.5/80 04-71 iche." 54-63 (cascading Inc..2 water): “loose caliche, ' 203-209. 216-224 (tools fell free). Chemical sample. table 6. Pump- ing test table 4. 188/51 Spnng 12-69 e2315 780 16 0-490 10-780 {(75) 12-69 1.200 141 . . . . 12-69 Ir Aquifers probably are 7dad Meadows. 12 475-780 pf('-) 04-71 1.200 150i 29.5/85 03-71 white lime,” 242-255; Inc.. 3 I 02-72 .... .... ..,. “brown limestone." 635- 690; or “red sandstone." 690-715. Minor cascad- ing water from 12 feet. Chemical sample. table 6. Pumping test, table 4. 188/51 Nye County 12-66 e2320 72 Limestone gravel. 55-60; 7de Land Co. dark dense. siliceous (Reed 9A) [Paleozoid] limestone. 65-72. No production test. 188/51 Spring 04-69 92315 282 14-3/4 0242 40-282 10 04-69 300 180 04-69 Obs Driller noted water from 7db2 Meadows, 10-1/4 240-282 “limestone." 15-30; lnc. “brown clay." 65-70; “limestone.' 145-160; 1113;] “loose caliche." 160- 188/51 Spring 02-72 e2320 495 16 . . . . . . . . 12 02-72 Ir 8cb1 Meadows, Low yield well. (Also Inc., 16 called Well No. 1A). 188/51 Spring 03-72 e2320 ?-500 16 0-? . , . . 13 03-72 11' High-yield well. possibly 8cb2 Meado'ys. (?) about 3,000 gal/min. Inc.. 1 1 Spring Meadows. Inc., (1968-71; Cappaert Enterprises in 1972) purchased holdings of Guerdon Industries, Nye County Land Co.. and George Swink, Spring Meadows, Inc., well numbers are those labeled on pumps during summer 1971. Where “Reed" numbers are given. his data (written commun., 1967) are used to supplement drillers’ logs and production records. Altitude referenced to mean sea level. to nearest foot. 3 Reported by driller except where noted. Static level except where noted. Production data before 1971 fr Drawdown is in feet below static lev pumping before measurement. om driller’s log or Reed (written commun., 1967). el and. where known, is followed by the duration of HYDROLOGIC FEATURES OF ASH MEADOWS OBS. WELL ISS/5I-7dh2 76b? [0 WELL 4 3 WELL 2 2 2 I 20 WELL 3 6 ‘— 11.! IE WELL 5 Z 30 I I I 9 E} / . 3 *— ‘3‘ 40 I II I2 0 I / l— I E 50 l5 0. / m I 0 WELL I ‘ I so I Is I 4 4 a I I 70 I ‘ 20 WELL I Pump on\ Pump 0H\A 9 ll MARCH 1971 FIGURE 8.-—Water levels and pumping historie‘ of wells in southern Ash Meadows during March 1971. 100 80 I - ——o—= ' . 60 Match pomt where. __ 20 4 1rTs/0 = 1 at indicated drawdown, and 40 4 Tt/r2 s1 = 1 at indicated time _ r/B Value identifies specific curve _ 10 in family of type curves presented _ 8 20 by Boulton (1963) Well 3 drawdown March 8—9 _ 6 T w 8,700 ,oo/ I— _, 4 E u. 10 E 8 - Delayed-yield type curve - >5 6 _ _- 2 0: 13 mm. L; l 8 4 - — — 3.9 ft - 3:4 r/B = 1 9 ATheis curve _ 1 ,1 185 min. ' 0~8 0 2 — '— 0 6 z / / / —-| — 1.7 ft ' a ,/ l 8 /B - 2 2 ’ 0‘4 ; 4min. r _ ' < 1 mm _ l IX)” _ O —' _ 0-9 ft Observation well 18 S/51—7db 05 _ drawdown March 15 I Well 2 recovery March 6—7 -" 0-2 rz 27,000 ,/ Tz 13,000 0.4 — T = transmissivity, ft2 /d,- _ s = drawdown in observation well; _ 0‘1 0 = pumping rate; _ t = time; 0'08 0-2 — r = distance from observation well to "- 0,06 pumped well; 0 S = storage coefficient. 004 0.1 10 100 1000 10,000 TIME SINCE WELL 1 STARTE D OR STOPPED PUMPING, IN MINUTES FIGURE 9.——Type-curve analyses of drawdown and recovery measurements during tests of well 1. March 1971. 19 DEPTH T0 WATERJN METRES DRAWDOWN OR RECOVERY, IN METRES i 20 EFFECT OF PUMPING 0N PUPFISH HABITATS IN ASH MEADOWS, NYE COUNTY, NEVADA TABLE 4.—Aquifer—test data for selected wells in Ash Meadows, Nye County, Nev. If, flows; discharge in gallons per minute in parentheses were reported or measured. 11, pumping level still declining at end of test. e, estimated from insufficient data or from specific capacity; includes effect of well-entry losses, which reduces apparent value. r, recovery-phase solution; others calculated from drawdown data] Elapsed Depth to water] Specific Well time Discharge Static pumping capacitrv 2 Well Trans 'ssivity3 Storage Date of test tested (hours) (gal/nun) (feet) (feet) (gal min' (14) observed (ft /d) coefficient and remarks 17S/50- 0.3 . . . , 3 2140 < 6 same e350 Feb. 23-25, 1971. Large 10cdd 4 1,280 part of discharge casA (well 8) 3; ~ $8 150 caded from 60 feet. ‘ l7S/50- 4,800 6x10‘3 1,200 feet from pumped 10cda well. Other effects. ~RogersSpring (17S/50-15ab) flow decreased from 590 to 555 gal/min. Soda Spring (17S/50-10bcd) flow decreased from 40 to 4 gal/min. Pumping has no measure- able effect on Fairbanks Spring (17S/50-9ac) or well 17S/50-14ca. 178/50 1 110 8 d220 0.4 same r30 March 1. 1967. Data from 17dd E.L. Reed4. Negative bounde at 8 ’ utes during recovery‘t’iiml 173/50- 4 1.400 f(6) d148 10 same 610 Mm}, 6, 1967. Data from 293d E.L. Reed4. 17S/50- 22.5 537 {(20) 38 14 same e3,700 Feb. 17-18, 1971. Paleozoic 23bb2 carbonate aquifer. (well 7) S 3 17 /50- 4. 00 3— ‘ ‘ be al. 231be 3,500 30 minute in rv Other effects. —Flow of numerous s 90400 minute interval. prings within 500 feet of umped well stopped or decreased during test. Well 17S/50-14ca decreased in flow from 24 to 21 gal/min. Total loss of natural discharge during test was about 170 gal/min. mping had no measurable effect on Longstreet Spring (17S/50-22aba). 17S/50- 2.7 900 48 87 23 same 127,000 March 10. 1967. Data from 36dd E.L. Reed“. Positive boundary after 60 min- utes of recovery. 188/50 1 1,300 f . . . . < 4 ' same April 8-16. 1971. Large Baa 120 900 > 220 part of discharge cas- (well 6) 170 860 > 220 caded from about 50 feet. Other effects—Crystal Pool (188/50-3adb) flow decreased from 2.930 to 2.480 gal/min after 170 hours of pumping. 188/50» 1.5 200 f(5) d >225 < 0.8 same March 18, 1327. Data from 5aa » E.L. Ree . l8S/50- 1.5 190 {(15) d433 <,0.4 same r24 Feb. 28, 1967 Data from 'lldd E.L. Reed". Negative boundary at 10 minutes during recovery; posi- tive boundary at 60 minutes. 188/51- 9 1.800 25 78 20 same 6.000 March 22, 1971. Part of 7bbb 1'6-000 discharge cascaded from ( well 5) about 42 feet. Measured in annulus outside slot- ted casing. Negative boundary at 20 minutes. 183/51- 18.000 21(10'3 Solutions show delayed 7bdb yield, partial penetra- (well 13) tion, or other evidence of 188/51- 19.000 3x10‘2 3‘3)? hydraul‘c “m“ec' 7ca + ' (well 4) Other effecta. —Pumping had no measurable effect on wells lBS/51-7daa (well 1), lSS/51-7dac (well 2). 18S/5l-7dad (well 3), 188/51-7db2. or 18S/51-12db; no measurable effects on spring flows. « f 20 254 1.1 same r82 March 3, 1967. Da from 18%311) 3 285 ( ) E.L. Reed, 196 . Re- (well 13) covery data showed neg- ative boundary at 10 minutes. - 1 120 <7 same r800 March 4-5 and 68, 1971. lei/am 1 1:23 1 > Obstruction prevented (well4) 31 1,000 measurement below 120 45 890 feet. Negative boundary at 60 minutes during re- covery. Other effects—Wells 188/51-7bbb (well 5). 188/51-7daa (Weill), 18S/51-7dac (well 2), 18S/51-7dad (well 3), and lSS/51-7db2 were observed. Solutions for all showed delayed yield, partial penetration or other evidences of poor hydraulic connection. 7—7 HYDROLOGIC FEATURES OF ASH MEADOWS 21 TABLE 4.—Aquer-test data for selected wells in Ash Meadows, Nye County, Nev. —Continued Elapsed Depth to water1 Specific Well time Discharge Static Pumping capacit 2 Well Trans ‘ssivity3 Storage Date of test tested (hours) (831/ min) (feet) (feet) (831 min‘ ft'l) observed (ft /d) coefficient and remarks 188/51- 500 1.650 3 56 same e8,300 February. 1971_ 7daa (well 1) 24 1.650 10 56 same . March 8-9, 1971' after 2_ (see remarks) day shutdown. Negative boundary after 20 min- utes. Apparent trans- missivity for rest of 34- hour test was 8.800 ft /d 188/51- 13.900 4x10‘2 March 8-9. 15m. All sol- 7dac utions show delayed (well 2) yield. partial penetra- 3 tion or other evidence of 188/51' 8,700 “‘10- poor hydraulic connec- 7dad tion. (well 3) 188/51- 27.000 6x10-4 7db2 Other effects.—Pumping had no measurable effect on wells 18$/51~7daa (well 1), 188/51‘7dac (well 2), 185/51-7dad (well 3). 188/51-7db2. or 18S/51-12db: no measurable effects on spring flows. 188/ 51- 20 1.200 8 70 7dac 220 1 .000 (well 2) <71 same April 5-6. 1971. Large part of discharge cascaded from about 60 feet. 185/51- 4.500 3x10'3 Solutions show delayed 7daa yield or partial penetra- (well 1) tion. 188/51- 12.700 3x10-2 7db2 Other effects. —Discharge of Jack Rabbit Spring (18S/51-18bc) began to decline within minutes after pumping started; declined from 410 gal/ min to 310 gal/ min after 1 day and to 180 gal/ min after 9 days of pumping. Well 3 (188/51-7dad) also affected, but cascading water and oil prevented accurate measurement. No effect on well 5 (18S/51-7bbb). 183/51- 2 1.200 20 E 170 7dad 54 1,150 (see remarks) (well 3) 190 1,000 2 6 same March 9-18. 1971. Minor part of discharge cas- cades from 12 feet. Static level affected by nearby pumping during test. Well has natural flow. e1,600 r5,900 18S/51- 3x10-4 7daa (well 1) 18.300 Drawdown-phase solution. March 9, 1971. Well 1 also pumping. but near steady state. 185/51- 21-000 5X10“, Recovery‘phase solution, 7de March 18. 1971. Other effects. ——Well 2 (18S/51-7dac) drawdown about 1 foot in 480 minutes. Discharge of Point of Rocks springs (188/51-7dba) declined slightly. No effect on Jack Rabbit Spring (18S/51-18bc) or well 5 (188/7bbb). 1 Static depth to water at start of pumping. 2 Gallons per minute discharge per foot of drawdown (pumping level minus stat level) in the well; effects of well-entry loses are included. 3 Cubic feet per day per foot width of aquifer under unit hydraulic gradient. Spring is particularly interesting because of the distance between them, about 1 mi (1.6 km). Complete discussion of the transmissivities and storage coefficients reported in table 4 will be deferred to a later section of the report. It should be re-emphasized here, however, that the inhomogeneity of the aquifer system and the errors inherent in measuring drawdown in wells with cascading water together make these data meaningless for quantita— tive applications. PUMPING RECORDS With the exception of minor use in watering shrubbery at Ash Meadows Lodge, all irrigation withdrawals of underground water in Ash Meadows 4 Unpublished consultant's report to Spring Meadows, Inc., dated June 1967 by Ed L. Reed and Associates. Midland. Texas. 5 Negative boundary indicates area of lower transmissivity within area of influence of pumped well. Positive boundary may indicate area of higher transmissivity within area of influence. are made by the Spring Meadows Ranch. Water from eight major wells, supplemented by three small- capacity wells and, where feasible, the flow of several springs, is used to irrigate more than 3,000 acres (12 km2) of crops. This pumping rate reached a peak of about 1,000 acre-ft (1.2 million m3) per month in both 1970 and 1971. Detailed records of the pumpage were not maintained after 1971. Those wells with field numbers 1 through 8, and 13, were active during 1971 until September, when wells 4, 5, and 6 were turned off by agreement with the Federal Government. Late in 1971 well 10 and unnumbered well 17S/50-10cda were pumped intermittently. Wells 16 and 17 were drilled and began production in 1972. Wells 9, 11, 12, and 17S/51-31dd j 22 EFFECT OF PUMPING ON PUPFISH HABITATS IN ASH MEADOWS, NYE COUNTY, NEVADA have produced only minor quantities. The other wells shown in figure 7 were not pumped during this study, but injection of water from King Pool into well 17S/50-36dd began on June 30, 1973, in an effort to support the water level in Devils Hole while litigation is continuing. For 1969 and 1970 there are no accurate discharge records. Records were to have been obtained by the use of accumulating discharge meters during the 1971 irrigation season. However, coarse detritus carried in the discharge stream eventually fouled these meters. During the spring of 1971, through frequent repair and exchange of meters, the field party was able to use the meters to obtain typical pumping rates for the main wells in the field. These were supplemented by current-meter measurements in irrigation ditches and by trajectory measurements of the discharge from open pipes. Electrical-power-consumption meters were read at least monthly from September 1970 through December 1971. The frequency of readings was weekly during the summer of 1971; during February to June 1971, most meters were read several times each week. Rates of power consumption were correlated with measured pumping rates and used to reconstruct the pumping history of each well in the field. During 1971, when discharges were well documented, the average error in the reported withdrawals probably is no greater than 10 percent. Because of varying lift, pump condition, and well efficiency, the withdrawals estimated for previous years may be in error by as much as 20 percent. Table 5 gives the estimated monthly withdrawals from individual wells that produced more than 200 gal/min (1,100 m3/d) during 1969, 1970, and 1971. These data show that the preponderance of pumping has been in the vicinity of Point of Rocks, or sec. 7, T. 18 8., R. 51 E. WATER-TABLE CONFIGURATION Water flowing southwestward to Ash Meadows in the regional lower carbonate aquifer is confined by the less permeable Cenozoic sediments that overlie the carbonate rocks. The potentiometric head in the lower carbonate aquifer and in the confined aquifers of the local subsystem increases with depth. Consequently, the water level in deep wells rises above that in shallow wells, and commonly the deeper wells flow without pumping. This is the condition expected in discharge areas, where flow has an upward component or at least the potential for upward flow exists. The water table is thus somewhat lower than water levels in the wells would indicate, but it is generally TABLE 5.—Estimated withdrawals in acre-feet from electrically pumped wells operated by Spring Meadows Inc, in Ask Meadows, Nye County, Neu, January 1969-January 1972 [Based on correlation of 1971 discharge rates with electrical power consumption. Estimated accuracy 1 20 percent in 1969, 1970; :10 percent in 1971] Well no. ield 188/51 188/51 188/51 188/51 lfig/m 188/50 178/50175/50 llé/E dac 7dad 7ca 7bb Location 7daa 7 3n 23bb IOodd 10bdb 1909 January - ‘ ~ 0 0 0 0 0 0 0 0.7 o 0.7 Febnhiary . . , 0 0 0 0 0 0 0 110 0 110 Mm ----- 0 0 o 0 0 0 o 0 o 0 A ril ....... o 0 0 0 0 0 o 0 o 0 ”EV -------- 0 0 0 0 0 0 0 0 0 0 June ------- 160 0 0 0 0 0 0 0 40 200 My -------- 150 0 0 o 0 0 0 0 41 190 August ..... 91 0 0 0 0 40 o .1 55 190 September, 33 91 o 6 0 0 0 82 53 260 October ..... 140 66 0 140 0 20 0 0 55 420 November . . , 130 90 0 110 0 14 0 97 53 490 December, ~,, 17 32 0 9 0 15 0 .7 34 110 Total 720 280 0 260 0 90 0 290 330 2.000 1970 January. . .. o 4 0 0 0 0 0 0 0 .4 Febniary... 0 .8 0 37 0 0 0 0 0 68 March ...... o .1 0 13 o 0 0 0 0 14 9121-11 ....... s 56 54 76 0 0 0 0 0 190 y ........ 200 74 120 62 340 0 0 0 0 800 June rrrrrrr 190 .80 110 120 330 25 0 0 0 750 July 44444444 180 83 76 120 240 27 0 120 0 350 August ..... 210 120 160 120 300 26 0 69 0 1.000 September ~ 190 110 160 110 270 26 25 15 0 910 October ..... 200 130 110 80 290 4 2 140 0 960 November . 1 190 100 45 120 270 0 14 140 0 870 December. , 1 81 120 12 70 120 0 0 60 0 460 Total 1.500 880 850 930 2.100 110 40 540 0 6.900 1971 January ..... o 0 32 15 73 0 0 o 0 120 February . . 190 0 0 34 130 0 7 9 0 370 h ...... 150 0 49 39 44 o 56 0 test 340 April ....... 120 65 74 43 49 30 39 0 0 420 May ........ 150 29 o 39 120 60 32 20 0 440 June ........ 240 87 81 120 95 9 44 39 10 770 July ....... 210 110 160 100 120 140 74 89 18 1,000 August ..... 210 130 160 77 120 130 64 85 20 1,000 September. . 200 130 150 120 135 141 13 20 20 630 October ..... 200 130 160 o o o 43 31 1 570 November . . . 180 120 160 0 0 0 59 48 0 560 December... 200 65 140 0 0 0 54 90 0 560 Total 2.000 870 1,200 490 790 450 480 480 71 6.900 1972 January... 100 0 0 0 0 0 0 290 0 2190 Pumping stopped on September 9. 1971. Well 8 assumed pumping, January 25-31, 1972. higher than the altitudes of discharging springs. Using the altitudes of the springs as lower limits and of the static water level in wells as upper limits for the water-table altitude, together with topography and a few precise data points such as Devils Hole, it is possible to construct an approximate contour map of the configuration of the water table. Figure 10 shows this configuration for the Ash Meadows region. HYDROLOGIC FEATURES OF ASH MEADOWS (16020” l|6°15' 36° 30' EXPLANATION —2|80—WATER-TABLE CONTOUR— Shows aliitude of water table. Contour interval 20 feet (Gmetres). Datum is mean ,4 sea level, 0 IMILE I? 05—55:: ZKILOMETRES 1”“ Contour Interval ZOOfeeHGlmehes) i ff 1 // a E $ (supplementary contours.40fee1 or|2 memesytrlib.a . "56° 25‘ Bose from U S. Geological Survey, Ash Meadows, |=62,500 FIGURE 10.—Generalized contours of water-table altitude in the Ash Meadows area. 23 —<_ 24 EFFECT OF PUMPING ON PUPFISH HABITATS IN ASH MEADOWS, NYE COUNTY, NEVADA Except in the northeast quarter of the area these contours show a continuation of the southwestward horizontal component of flow existing in the regional aquifer. Within the group of limestone hills bordering Ash Meadows on the east, however, there is mounding of the water table and consequent flow to the north and northeast also. Faults and joints that rupture the lower carbonate aquifer have apparently provided paths for upward flow. Except beneath these hills and the steep alluvial slopes that border them, the water table conforms to the land surface quite well. In most of the area along Carson Slough south of Fairbanks Spring, encompassing the western one-third of the area in figure 10, the water table is at the land surface. WATER QUALITY TEMPERATURE Tables 2 and 3 give the temperatures of water from the springs and wells in the Ash Meadows area. The water in Devils Hole remains quite constant at about 33.5°C (92°F to 93°F). Well 7, drill hole 17S/50-14cac, and one spring at Point of Rocks discharge water from the lower carbonate aquifer at a temperature of 34.5°C (94°F). This is 15.5°C (28°F) higher than the mean annual air temperature, which ground water tends to approach, and indicates that the water emerging from the regional aquifer has circulated deeply before being forced up along fault zones. Springs close to the regional source (fig. 7) are commonly a few degrees cooler but still much warmer than the mean annual temperature. Springs located 0.5 mi (0.8 km) or more from the outcrops of Paleozoic rocks generally have temperatures below 28.5°C (83°F), but Crystal Pool discharges water at 32°C (90°F), indicating a rapid rate of flow from the regional aquifer to the spring. The small discharge of Cold Spring (19.5°C or 67°F) apparently spends enough time in transit to approximate the mean annual temperature. Water from the wells is generally somewhat cooler and less predictable than that from the natural discharge points, that is, the springs. Well 8, although it is comparable in discharge to the major springs around it, discharges water at 21°C (70°F), about 6°C (10°F) cooler than the spring flow. In the Point of Rocks area wells 1, 2, 3, and the flowing observation well 188/51-7db2, respectively, have temperatures of 28°, 26.5°, 29.5°, and 305°C (82°, 80°, 85°, and 87°F), which again underscores the complexity of the local flow subsystem. The variability in temperatures of water pumped from different wells indicates that the wells, even where close to one another, produce from different aquifers that vary in their degree of adjustment to the mean annual temperature. CHEMISTRY The locations and general chemical character of water samples collected during this and previous studies are shown in figure 11. An arbitrary number has been assigned each location and date of sampling to minimize space requirements. Table 6 gives the identification and complete analyses of the samples, as recorded in the files of the Geological Survey and, where noted, by Ed L. Reed and Associates (written commun., 1967). Winograd and Thordarson (1975) have discussed the chemistry of water in southern Nevada in detail. To reiterate their work here would not further the stated objectives, but selected samples show the general chemical framework of the Ash Meadows area. On the left map of figure 11, sample 6, from Army well 1 along US. Highway 95 near the Nevada Test Site, shows a clear dominance of calcium plus magnesium over sodium. This chemical character and the position of Army well 1 within the Ash Meadows flow system suggest that its water is typical of relatively recent recharge from the Spring Mountains. ' Comparison of the analysis of this sample with that of Devils Hole water (sample 42 in table 6) shows that additions of all major constitutents, and particularly of sodium, are made to the water before its arrival at the discharge area. Water pumped from two wells penetrating carbonate rocks northeast of Devils Hole (sample 3 from the Geological Survey tracer site and sample 54 from a private well) are more similar chemically to Devils Hole water. GENERAL CHARACTER With the exception of Big Spring all major springs in Ash Meadows, those discharging about 500 gal/min (2,700 m3/d) or more, and Devils Hole show great uniformity in chemical character. Sodium is typically 41 plus or minus 3 percent of the total cations, and calcium dominates magnesium only slightly. Potas- sium, strontium, and lithium are minor constituents of all samples. - Among these natural discharge points the bicarbonate ion is about 70 percent of total anions, followed by sulfate (about 20 percent), chloride (about 8 percent), and fluoride (less than 2 percent). Samples from well J -12 (sample 0) and Ash Tree Spring (sample 9) are shown in figure 11 and in table 6 to illustrate the character of water from the volcanic terrane of the Pahute Mesa ground-water system, which is contiguous to the western boundary of the Ash Meadows system (Rush, 1970; and Winograd and Thordarson, 1975). As shown on the left side of figure 11, the samples differ from those in the Ash Meadows system by lower dissolved solids, dominance of sodium r—i HYDROLOGIC FEATURES OF ASH MEADOWS 25 over other cations, and greater concentrations of silica and nitrate. The ratio of calcium to magnesium is about 2:1 in the Pahute Mesa system, whereas it is between 3:2 and 1:1 in the Ash Meadows system. This uniform chemical picture of the Ash Meadows flow system changes when the wells and smaller springs are considered. The longer period of residence in local aquifers results in enrichment of sodium to dominance among the cations, as shown on the right side of figure 11. Sulfate, and chloride to a lesser degree, become relatively more important among the anions. Water from wells 1 and 3 (samples 78 and 84 respectively) have anion compositions of about 30 “6' I5 IIS’OU R49: 350: R5! RSZE no I I l 1. __ i— _____ _____r _______ I. ___________ I00 I l I — 1 i II + I ll — 36'45' I | ' l n45 l l I I l I l I I I I I ______ _____ T_.___.____.I.__._____JI.___.______l I I I l I : I I o Lalhrop Wells I l | I I II T|5S I | I l l I I s O T s 5 I6 0 43' _ w, o _ 30. .l" Mike" I‘. ‘7. roI O 54 a? ? \ _____ p— TIBS TIES TISS oDnih Valley 0 4/ 9 Ju all n W " ° @905 Ties i664, IL. PM T205 ’ ”l - 0/;{>C‘oo 5' 5' ( J_J’Alk€|ll flat + \‘5’ "3 ' I 0 2 4 6 MILES O 2 4 SKILOMETRES ale-25' — I + percent bicarbonate, 50 percent sulfate, and 20 percent chloride. The enrichment of both sulfate and chloride is greatest among all the samples in the water from well 2 (sample 81) and in the 1970 sample (96a) from Jack Rabbit Spring. In these samples bicarbonate is only about 10 percent while sulfate and chloride are increased to about 60 percent and almost 30 percent respectively. Jack Rabbit Spring is particularly interesting because sample 96, taken in 1966 before development of the well field, was virtually identical in character to water from the other major natural discharge points. A decrease of 2°C (35°F) in temperature accompanied the change in “6‘20‘ R 50 E fag]? ,ar «5” RSIE Tl75 TIES / \41‘ % al / _ 04>? ' ~o ‘ \ I IOZ 0 l 2 SMILES 0 I 2 3 KILOMETRES EXPLANATION Sampling points MIllquu‘Ivolenis per litre 5 O 5 lO . . fi—w—r‘I—fl 0 Well In Pokemon: carbonate rocks Co+Mq HC03+ C03 0 Well in valley fill N0+K+ Sr SgL-i-CH'F 0‘ Spring $I02 N03 I00 50 5 IO 96 Water sample number imablee O Milligrams per lilre FIGURE 11.—Locations of sampling points and distribution of dominant and selected minor constituents of water samples from the Ash Meadows region. ' i 26 EFFECT OF PUMPING ON PUPFISH HABITATS IN ASH MEADOWS, NYE COUNTY, NEVADA TABLE 6.—Chemical analyses of water samples from Ash Meadows and vicinity, Nye County, Nev. [Analyses by the U.S. Geological Survey except as noted in first column; R. reported by Ed L. Reed and Associates (written commun.. 1967); e. estimated from partial data; .... not reported] M'lli ams er litre Millieguivalents per litre #5 Percent of total cations or anions Location- Total . Water S/E-Sec. . hard- Cations Anions 3 sample and Date Temg 135- ness as . SAR no. index Source Mo.-Yr. (°C/° ) sol. 1 C3003 S102 Li B N03 Ca Mg Na K Total HC034 S04 Cl F Total 0 14S/50- Well 04-69 26.5/80 205 46 56 0.04 0.13 9.7 0.70 0.21 1.74 0.14 2.80 1.92 0.46 0.18 0.11 2.83 2.6 06(J12) J-12 25 7.5 62 5.0 99.6 68 16 6.4 3.9 94.3 3 l6S/5l- Tracer l 02-68 30.5/87 400 188 22 .08 .27 < .1 2.25 1.48 2.70 .20 6.66 4.65 1.33 .59 .11 6.68 2.0 27ba32 well 2 34 22 41 3.0 99.5 70 20 8.8 1.6 100 6 16S/53v Army 0469 30.5/87 308 202 20 .04 .20 1.1 2.20 1.81 1.57 .15 5.76 4.23 1.06 .37 .06 5.74 1.1 05b1 well 1 38 31 27 2.6 99.5 74 18 6.4 1.0 99.7 9 17S/49- Ash Tree 07-70 22/72 282 56 76 .07 .28 6.7 .75 .35 2.39 .23 3.74 2.56 .73 .19 .14 3.73 3.2 35dd Spring 20 9.4 64 6.1 99.5 69 20 5.1 3.8 97.1 12 17S/50- Fairbanks 11-66 27/81 424 199 22 .09 .51 < .1 2.40 1.56 3.00 .20 7.19 4.92 1.56 .48 .09 7.05 2.1 09adc Spring 33 22 42 2.8 99.6 70 22 6.8 1.3 100.0 15 178/50 Soda 1166 23/73 488 161 35 .10 .99 < .1 1.80 1.40 4.61 .26 8.10 5.41 1.94 .76 .11 8.22 3.6 10bcd Spring 22 17 57 3.2 99.6 66 24 9.2 1.3 100.0 18 17S/50- WellS 10-70 21/70 430 100 31 .14 . . . .5 1.10 .90 4.78 .38 7.21 4.85 1.54 .62 .11 7.13 4.7 lOcdd 15 12 66 5.3 99.3 68 22 8.7 1.5 99.9 21 17S/50- Rogers 11-66 28/82 412 205 23 .09 .31 < .1 2.35 1.73 3.00 .20 7.31 4.95 1.62 .59 .08 7.24 2.1 15ab Spring 32 24 41 2.7 99.6 68 22 8.1 1.1 100.0 24 178/50. Well 08.62 195/67 447 209 23 .10 .28 .9 2.50 1.65 2.91 .24 7.30 5.00 1.64 .65 .06 7.36 2.0 153d 34 23 40 3.3 100.3 68 22 8.8 .82 99.6 R27 17S/50- Well 14 03-67 19.5/67 838 248 ... ... . .. ... . .. ... 9.31 ... e14.35 9.51 3.16 1.58 e.1 €14.35 5.9 17dd e65 e66 e22 ell e1 30 17S/50- Long» 11-66 28/82 419 199 22 .09 .26 .4 2.40 1.56 3.00 .20 7.19 4. 1.56 .48 .09 7.06 2.1 223ba street 33 22 42 2.8 99.6 70 22 6.8 1.3 999 Spring 33 l7S/50- Spring 10-70 33.5/92 376 190 22 .08 . . . .3 2.25 1.56 3.13 .21 7.18 4.41 1.71 .56 .09 6.77 2.3 23bbc 32 22 44 2.9 99.6 65 25 8.3 1.3 100.0 36 17S/50- Well 7 10-70 34.5/94 393 190 22 .08 . . . .1 2.25 1.56 3.13 .21 7.18 4.61 1.67 .56 .09 6.93 2.3 23bb2 31 22 44 2.9 99.6 67 24 8.1 1.3 100.0 39 17S/50- Well 10 08-62 19.5/67 733 28 67 .14 1.4 < .1 .14 .24 10.87 .38 11.81 8.10 2.19 .73 .17 11.19 27.6 29add 1.2 2.0 92 3.2 98.4 72 20 6.5 1.5 100.0 42 17S/50- Devils 12-66 335/92 423 225 22 .09 .32 .2 2.50 1.97 2.83 .19 7.52 5.08 1.58 .56 .08 7.30 1.9 36dc Hole 33 26 38 2.5 99.6 70 22 7.7 1.1 100.0 45 17S/50- Well 03-67 33.5/92 432 199 24 .08 .29 < .1 2.30 1.65 3.00 .22 7.20 4.93 1.60 .56 .09 7.18 2.1 36dd 32 23 42 3.1 99.6 69 22 7.8 1.3 100.0 48 17S/51- Well 01-61 23/73 372 180 18 . . . . . . < .1 1.95 1.65 3.00 .26 6.86 5.74 1.10 .17 .03 7.04 2.4 01a1 28 24 44 3.8 99.8 82 16 2.4 .2 100.6 51 17S/51- Well 0371 25.5/78 435 130 22 .12 . . . < .1 1.50 .99 5.22 .16 7.91 5.13 1.87 .54 .08 7.62 4.7 31ddd 19 13 66 2.0 100.0 68 25 7.1 1.0 101.1 54 17S/52 Well 04-58 28/82 342 176 18 . . . . . . < .1 1.70 1.81 2.65 .18 6.34 4.49 1.31 .59 .06 6.45 2.1 08c1 27 29 42 2.8 100.8 70 20 9.1 .93 100.0 R57 18S/50- Well 6 03-67 31/88 416 190 _ .. ... ... ... ... ... 3.05 ... e6.93 4.65 1.60 .59 e0.1 e6.93 2.2 033a ... ... e44 ... ... e67 e23 98.5 e1.4 ... 60 188/50- Crystal 11-66 33/91 432 184 25 .09 .31 < .1 2.00 1.65 .313 .22 7.03 4.56 1.69 .62 .09 6.96 2.3 OSadb Pool 28 23 45 3.1 99.6 66 24 8.9 1.3 100.0 R63 188/50- Well 04-67 235/74 792 22 22 . . , . .. . .. . .. . , . 10.35 . . . e10.89 1.74 3.54 1,18 e0.1 4e10.89 22.0 05aa ... ... e95 ... ... e16 e33 e11 e1.0 ... R66 18S/50- Well 02-67 30.5/87 412 126 . .. . ., ... ... . .. ... 4.39 ... 97.00 4.98 1.33 .59 8.1 e7.00 3.9 11d e63 e71 e19 e8.4 e1.4 69 18S/51- Well 5 10-70 31.5/89 335 190 23 .08 , . . .3 2.20 1.56 3.04 .21 7.04 3.51 1.64 .56 .08 7.14 1.9 07bbb 31 22 43 3.0 99.6 61 28 9.7 1.4 .. _ 69 23 7.8 1.1 adj.5 R72 lSS/51~ Well 13 03-67 305/87 410 192 . .. . .. ... ... ... ... 3.09 ... (27.02 4.98 1.35 .59 e.10 e7.02 2.22 07bdb ... ... e44 ... ... e71 e19 e8.4 e1.4 ... 75 188/51. Well 4 10-70 30.5/87 428 210 23 .09 . . . 2.6 2.54 1.73 3.39 .21 7.90 4.80 1.73 .71 .09 7.37 2.3 07caa 32 22 43 2.7 99.6 65 23 9.6 1.2 - - - 68 22 9 o 1.1 adj.5 78 133/51- WeU 1 10-70 28/82 883 300 23 .12 . . . 7.1 2.99 2.96 7.40 .28 13.68 4.31 6.87 2.68 .08 14.05 4.3 07daa 22 22 54 2.0 99.6 31 49 19 .57 99.2 81 188/51- Well 2 10-70 26.5/80 2160 690 23 .19 . . . 27 6.99 6.75 17.40 .49 31.75 3.97 195 8.46 .07 32.09 6.6 07dac 22 21 55 1.5 99.6 12 61 26 22 99.7 84 188/51- W8" 3 10-70 295/85 617 270 24 .12 . . . 5.6 2.94 2.47 5.66 .23 11.35 3.00 4.79 2.14 .09 10.11 3.4 07dad 26 22 50 2.0 99.6 30 47 21 .89 99.1 f. HYDROLOGIC FEATURES OF ASH MEADOWS 27 T ABLE 6.—Chemical analysis of water samples from Ash Meadows and vicinity, Nye County, Nev. —Continued Milligrams per litre Millie uivalents er litre Location Total . Percent of total cations or anions Water S/E-Sec. . hard- Cations Anions 3 sample and Date Temp D15. mass as _ “A“ no. index Source Mo.-Yr.(°C/° ) sol1 CaCO3 $102 Li B N03 Ca Mg Na K Total H0034 804 Cl 1“ Total 87 185/51 Ind.Rk. 11-70 33.5/92 412 203 22 .09 .35 .2 2.30 1.73 2.96 .19 7. 4.98 1.62 .59 .08 7.27 2.1 om,“ spring 32 24 41 2.6 99.4 69 22 8.1 1.1 100.0 90 18S/51- Many 10-70 31/88 340 200 22 .08 .2 2.25 1.65 3.04 .21 7.18 3.65 1.54 .59 .08 5.86 2.2 07dba springs 31 23 42 2.9 99.6 62 26 10 1.4 . '.'5 69 21 8.2 1.1 add. 93 188/51» King 11-66 32/90 408 208 22 .09 .30 .2 2.40 1.73 2.91 .18 7.25 4.98 1.58 .59 .11 7.26 2.0 07dbb Pool 33 24 40 2.5 99.6 69 fl 8.1 1.5 100.0 93a do do 10-70 32/90 371 190 22 .08 .3 2.25 1.56 3.04 .20 7.08 4.56 1.64 .56 .08 6.84 2.2 32 22 43 2.8 99.6 67 24 8.2 1.2 . . . 68 23 7.9 1.1 adj.5 96 185/51- Jack Rab. 11-66 28/82 412 200 22 .08 .38 1 2.23 1.75 2.96 .20 7.17 4.92 1.62 .56 .08 7.18 2.1 18dbd Spring 32 24 41 2.8 99.6 69, 23 7.8 1.1 100.0 96a do do 10-70 25.5/78 2140 800 24 .21 29 7.98 7.81 18.27 .54 34.73 2.75 $.40 8.75 .09 32.46 6.5 23 22 53 1.6 99.6 8.5 63 27 .27 98.6 99 18S/51- Big ‘ 11-66 28.5/83 430 190 28 .12 .44 .2 2.20 1.56 4.22 .22 8.25 5.21 2.19 .71 .07 8.18 3.1 19acb Spring 27 19 51 2.7 99.4 64 27 8.7 .9 100.0 102 188/51- Bole . 07-62 22/72 500 173 1.0 1.90 1.56 4.61 .24 8.32 5.01 2.35 .76 .05 8.17 3.5 303 Spring 23 19 55 2.9 99.9 61 29 9.3 ' .61 99.9 1 Dissolved-solids residue on evaporation at 180°C. 2 Missing percentage of cations is mainly Sr; minor Li. Missing percentage of anions is mainly N03; minor P04. 3 Sodium-adsorption ratio. chemistry. The 1970 samples from Jack Rabbit Spring and well 2 have almost five times the dissolved-solids concentration of the water from the lower carbonate aquifer. These results confirm the close hydraulic relationship shown between well 2 and Jack Rabbit Spring during the pumping tests of 1971. LITHIUM The lithium concentration in water from the lower carbonate quifer ranges between 0.08 and 0.10 mg/l, but well 2 and Jack Rabbit Spring have about 0.2 mg/l. Wells 1 (sample 78), 3 (sample 84), 8 (sample 18), 10 (sample 39), and well 17S/51-32dd (sample 51) have lithium concentrations ranging from 0.12 to 0.14 mg/l. Big Spring (sample 99) also has 0.12 mg/l and Bole Spring (sample 102) has 0.17 mg/l lithium. All samples have lithium concentrations greater than 0.10 mg/l also contained more than 50 percent sodium in their total cation concentration. Well J ~12 (sample 0) and Ash Tree Spring (sample 9) have only about 0.04 mg/l and 0.07 mg/l, respectively. BORON Boron analyses were made for only a few of the samples. Water in the regional aquifer, as indicated by Devils Hole and most of the major springs, has boron concentrations ranging between 0.26 and 0.38 mg/l. Big Spring (sample 99) is slightly enriched in boron, having 0.44 mg/l. The highest boron concentration observed (1.4 mg/l) is in sample 39 from well 10. Boron is the only constituent detected for which Fairbanks Spring (sample 12, 0.51 mg/l) differs from the water in the regional aquifer. Nearby Soda Spring (sample 15) has about 1 mg/l boron. SILICA Silica is generally present with concentrations less 4 4.33 meq/ 1 C03 (40 percent) in sample 63: no C03 in other samples. 5 Anions adjusted to same meq/l as cations, assuming precipitation of CaC03 from anion sample before analysis. than 25 mg/l. Samples from the Pahute Mesa ground- water system (samples 0 and 9) show 2 to 3 times this concentration, as does well 10 (sample 39). NITRATE Nitrate is a minor constituent of most samples, being generally less than 0.5 mg/l. The highest concentrations are in water from the 1970 sample (96a) of Jack Rabbit Spring (29 mg/l) and from well 2 (27 mg/l, sample 81). Wells 1, 3, and 4 (samples 78, 84, and 75) have moderate concentrations (2.6 to 7.1 mg/l), as do the samples (0 and 9) from the Pahute Mesa flow system. CHEMICAL STABILITY OF DEVILS HOLE AND KING POOL The change noted above in the quality of water from Jack Rabbit Spring raises the question of whether the chemistry of Devils Hole has also changed. In addition, water from King Pool was compared to that of Devils Hole before injection into well 17S/50-36dd was begun. Samples taken in June 1973 were analyzed by Southwestern Laboratories, Midland, Texas, and reported to the authors by Ed L. Reed and Associates (written commun., July 1973). In table 7 these analyses are compared to each other as well as to earlier analyses of each source by the Geological Survey. Table 7 shows that the samples are all very similar chemically. The exceptions are a tenfold increase in nitrate in water from both sources and a possible slight increase in chloride. It is highly probable that differences in analytical technique, which are particularly critical in anion analysis, account for these apparent increases. The nitrate content could also result from reactions on organic materials in the unfiltered samples taken in 1973. h 28 TABLE 7.—Comparative analyses of samples taken at different times from Devils Hole and King Pool [Southwestern Laboratory (SWL) data from Ed L. Reed and Associates. written commun.. July 1973] Devils Hole [ King Pool Date sampled - - 1-22-53 12-9-66 6-15-63 11-21~66 10~4~70 6-14-73 Laboratory. USGS USGS SWL USGS USGS SWL Diss. so 'ds (mg/ll . . . 425 423 398 408 371 389 Major cations [mg/l] Ca ........ 51 50 48 48 45 47 Mg ........ 21 24 24 21 19 25 Na ........ 66 65 69 67 70 65 Major anions [mg/l] H003 ..... 311 310 304 304 2278 300 $04 ....... 79 76 80 76 79 77 Cl ......... 22 20 25 21 20 25 F ......... 1.6 1.6 1.4 2 1.5 1.4 N03 ....... .5 .2 2.9 .2 .3 2.7 Minor ions [mg/l] B ......... .38 32 08 .30 .08 Fe (total) . . .04 < .05 .00 .09 < .05 Se ........ .- .005 ~- -- < .005 As ........ -- .01 -- -- < .01 Mn ........ < .01 < .05 .03 < .01 < .05 lDissolved solids by Geological Survey determined as residue upon evaporation at 180°C; Southwestern Laboratory values are calculated. 2Imbalance in total cations and anions indicates precipitation of H003 ion before analysis of anion sample. QUALITY FOR IRRIGATION The suitability of water for irrigation decreases as either the conductivity or the sodium-adsorption ratio (SAR) increases. The U.S. Department of Agriculture classification of irrigation waters is shown in figure 12; descriptions of the use of these classes given below are from Bateman, Mindling, Naff, and Joung (1972, p. 42-43): The classification of irrigation waters with respect to SAR is based primarily on the effect of exchangeable sodium on the physical condtion of the soil. Sodium-sensitive plants may, however, suffer injury as a result of sodium accumulation in plant tissues when exchangeable sodium values are lower than those effective in causing deterioration of the physical condition of the soil. Low-Sodium Water [Sl] can be used for irrigation on almost all soils with little danger of the development of harmful levels of exchangeable sodium. However, sodium-sensitive crops such as stone-fruit trees and avocados may accumulate injurious concentrations of sodium. Medium-Sodium Water [S2] will present an appreciable sodium hazard in fine-textured soils having high cation-exchange- capacity, expecially under low-leaching conditions, unless gypsum is present in the soil. This water may be used on coarse-textured or organic soils with good permeability. High-Sodium Water [S8] may produce harmful levels of exchangeable sodium in most soils and will require special soil management—good drainage, high leaching, and organic matter additions. Gypsiferous soils may not develop harmful levels of exchangeable sodium from such waters. Chemical amendments may be required for replacement of exchangeable sodium, except that amendments may not be feasible with waters of very high salinity. Very High-Sodium Water [St] is generally unsatisfactory for irrigation purposes except at low and perhaps medium salinity, EFFECT OF PUMPING ON PUPFISH HABITATS IN ASH MEADOWS, NYE COUNTY, NEVADA where the solution of calcium from the soil or use of gypsum or other amendments may make the use of these waters feasible. Sometimes the irrigation water may dissolve sufficient calcium from calcareous soils to decrease the sodium hazard appreciably, and this should be taken into account in the use of 01—83 and C1-S4 waters. For calcareous soils with high pH values or for non-calcareous soils, the sodium status of waters in classes 01-83, 01-84, and C2-S4 may be improved by the addition of gypsum to the water. Similarly, it may be beneficial to add gypsum to the soil periodically when 02-S3 and 03-82 waters are used. Low-Salinity Water [CI] can be used for irrigation with most crops on most soils with little likelihood that soil salinity will develop. Some leaching is required, but this occurs under normal irrigation practices except in soils of extremely low permeability. Medium-Salinity Water [02] can be used if a moderate amount of leaching occurs. Plants with moderate salt tolerance can be grown in most cases without special practices for salinity control. High-Salinity Water [03] cannot be used on soils with restricted drainage. Even with adequate drainage, special management for salinity control may be required and plants with good salt tolerance should be selected. Very High Salinity Water [C4] is not suitable for irrigation under ordinary conditions. but may be used occasionally under very special circumstances. The soils must be permeable, drainage must be adequate, irrigation water must be applied in excess to provide considerable leaching. and very salt-tolerant crops should be selected. Boron, although required in small amounts for proper plant nutrition, is toxic to some plants in larger quantities (Walker and Eakin, 1963). The boron hazard presented by Ash Meadows waters cannot be evaluated completely because of the limited number of analyses made. Well 10, however, with 1.4 mg/l boron, presents a high hazard to sensitive crops and a low hazard only to very tolerant crops (Scofield, 1936). Water from Big Spring and Fairbanks Spring may be moderately harmful to sensitive crops. The conductivities and sodium-adsorption ratios for sources of irrigation water in Ash Meadows are plotted in figure 12. Well 10 (sample 39), rated 03-84, has little value for crop production, and contemplated use should also consider the boron hazard noted above. With some precautions the water from well 2 (sample 81) or Jack Rabbit Spring (sample 96a), rated 04-82, can be used to a limited degree. The Spring Meadows Ranch mixes well 2 water with that from wells 1 and 17 and applies it mainly to fields that are heavily treated with gypsum. Class C3-Sl water from wells 1 and 3 and from Big Spring and Bole Spring is used successfully to irrigate bermuda grass, which is relatively tolerant of salt (Bateman, Mindling, Naff, and J oung, 1972). Alfalfa is irrigated by wells 1, 3, and 17, but, wherever possible, it is mixed with King Pool water (class 02-81) to reduce the salinity hazard. No analysis of water from well 17 is available, but hydraulic considerations suggest that it is similar to water from wells 1 and 3. The remaining irrigation sources fall within class OBSERVED EFFECTS OF PUMPING C2-Sl. Except for application on the poorly drained land along Carson Slough, this water is of moderately good quality. QUALITY FOR DOMESTIC USE With few exceptions the water sources in Ash Meadows do not exceed concentrations recommended by the U.S. Public Health Service (1962) for any chemical constituent other than .fluoride. All samples reported from Ash Meadows exceed the recommended limit for fluoride (0.8 mg/l under the existing temp- erature) by a factor of 2 or more. Dental fluorosis and discoloration may occur in the teeth of children raised here. Recommended maximum concentrations of sulfate and chloride are exceeded in wells 1 and 2 and in the 1970 sampling of Jack Rabbit Spring. OBSERVED EFFECTS OF PUMPING The effects of pumping were monitored during 1971 and 1972 by water-level recorders in Devils Hole, in several observation wells, and in flumes and weirs f 29 installed in most of the major springs. (See table 2.) Moderately detailed records of pumpage from the production wells in 1971 were reconstructed from electrical-meter readings, discharge measurements, and frequent observations of whether or not they were pumping. Because gaps in the hydrograph of Devils Hole had occurred before, well 17S/50-36dd was instrumented in January 1971 as a precaution against lost record. An excellent correlation was established between the depths to water in this well and in Devils Hole, which is about 900 ft (275 m) west of the well. EFFECT ON DEVILS HOLE WATER LEVEL During the aquifer tests of the individual production wells, no effects on the water level in Devils Hole were discernable. Daily fluctuations of the pool (as much as 0.5 ft or 15 cm) would easily have masked any changes due to pumping. The correlation between gross pumpage from the well field and the water level in Devils Hole, however, [00 500 IOOO 5000 _ I I I I I I II I I I I 30 SAMPLE IDENTIFICATION 3 _ .d _ Class c2-31 Class 03-51 26 - a Soda Spring g Well 1 A b Well 8 :1 Well 3 E " " c Well 7 In Big Spring q; ,0 _ _ e Observation well n Bole Spring -' In 17S/51-31dd 9 _ _ 20 f Well 5 Class 03—84 '2 j Point of Rocks 0 a: I8 - spring group (1 Well 10 a: z * Fairbanks Spring :1 9 ' ‘ * Rogers Spring Class C4—SZ < E N _ _ * Longstreet Spring I g m * Devils Hole h Well 2 z m _ - * Observation well k Jack Rabbit 2 2 17S/50-36dd Spring (1970) 8 | l0 '- IO * Well 6 m 2 * Crystal Pool 2 " n k ' * Well 13 8 _ co _ * Well 4 u) _ * King Pool a, _ _ * Jack Rabbit Spring (1966) O I I I I I I I I I I I I CI C2 C3 C4 100 ' 250 750 2 250 5000 CONDUCTIVITY (micromhos /cm at 25°C) SALINITY HAZARD—7- FIGURE 12.-Classification of irrigation water from Ash Meadows sources by conductivity and sodium-adsorption ratio. Classification diagram from U.S. Salinity Laboratory Staff (1954). —<— 30 EFFECT OF PUMPING 0N PUPFISH HABITATS IN ASH MEADOWS, NYE COUNTY, NEVADA is evident in figure 2. The pumpage records in table 5 indicate that the decline of water level in June and July 1969 must have resulted from well 1 or well 13 unless other wells were pumped without electrical power, in which case no record of this pumping is available. The significantly greater decline from August through November 1969 correlates with additional pumping from wells 2 and 4 and lesser' withdrawals from wells 6 and 8. The 1970 pumping season provides even less insight into the effects of individual wells. Pumping began near the end of April, with wells 1, 2, 3, 4, and 5 operating at or near their capacities, and the water level in Devils Hole began a relatively uniform decline until pumping was curtailed in December 1970. Moderate reductions in the use of wells 3 and 5 may be responsible for the decreased rate of drop in July. Reduced production from wells 4 and 6 may account for the leveling of the hydrograph in October. In 1971, however, the pumping history was more varied, and individual wells could be evaluated more » etres feet ‘GI SHER 03 2.2 0 q 2.4 2.6 O a 2.8 O '0 3.0 3.2 b 3.‘ _ 3.6 3.8 'n 4. O MEAN DAILY DEPTH OF WATER IN DEVILS HOLEl IN FEET AND METRES BELOW COPPER WA APPROXIMATE PERIODS AND RATE OF PUMPING DEVILS HOLE “ easily. Figure 13 shows the mean daily water levels computed from the hydrographs of Devils Hole and well 17S/50-36dd and the pumping history recon- structed from the detailed field observations. The observation well shows greater response than does Devils Hole to the pumping of some wells and thus allows subtle deviations of the Devils Hole hydrograph to be detected. Although the early February 1971 decline in the well and Devils Hole might be attributed to either well 1 or well 4, their recovery, beginning about February 10, correlates only with the shutdown of well 4. The effects of well 5 can be detected from the period mid-March to mid-April, from the 0.1 ft (3 cm) recovery of the observation well in late May, and from the smaller recovery in late June. Limited use of well 6 continued to prevent identification of its effects. The pumping histories of wells 7, 8, and 13 varied sufficiently that their effects, if significant, should have been detectable; the hydrographs show no apparent reaction to these wells. Considering their feet metres 49-2 — I5.0 49.4 49.6 — '5" 49.8 5 N 50.0 50.2 - 57' u ‘ 50.4 I .5 a 50 .6 5 0.8 ITS/50-36dd. IN FEET AND METRES MEAN DAILY DEPTH T0 WATER IN WELL EXPLANATION gal/min "Is/d 2000. I0,000 [00015000 0 0 Pumping run In gallons per minute and cubic metres per day. (Dashed where variable rate is averaged over period) |97I FIGURE 13.—Mean daily water levels in Devils Hole and observation well 17S/50-36dd and estimated pumping from wells in Ash Meadows during 1971. Dashed segments in upper hydrograph denote extrapolation through periods of no data. OBSERVED EFFECTS OF PUMPING 31 distances from Devils Hole (except for well 13), their small to moderate discharges, and the chemistry of the water from well 8, this observation was to be expected. On August 4, 1971, the senior author submitted to the U.S. District Court, Las Vegas, Nev., an affidavit stating his opinion that, among all wells of the field, wells 4, 5, and 6 had the most direct effects on the water level in Devils Hole. This conclusion was based on their yields and closeness to Devils Hole, the similarity in chemistry and temperature of their waters to that of Devils Hole, and the correlations of pumping history with the hydrograph discussed above. In late August, the Federal Government and the ranch reached an agreement to shut down wells 4, 5, and 6, and the immediate recovery beginning on September 9, 1971, is apparent on figure 13. The observation well recovered 0.5 ft (15 cm) within 1 week and 0.7 ft (21 cm) by the end of September. The change in Devils Hole was equally encouraging, recovering almost 0.2 ft (about 5 cm) by the end of the month. This rate compared favorably with the rapid drawdown of 0.3 ft (9 cm) in a 20-day period during heavy pumping of the field in June and July 1971. The variability in the mean daily hydrograph levels, which had diminished during the summer drawdown, returned in late September. In October 1971 the hydrographs of Devils Hole and well 17S/50-36dd resumed slow and parallel declines. It became evident that the cessation of pumping for wells 4, 5, and 6 had produced only about 0.2 ft (6 cm) of recovery in Devils Hole and that continued pumping of wells 1,2, or 3 was lowering the water level. The recorder in Devils Hole malfunctioned in mid- December 1971, but the recorder in well 17S/50-36dd continued to operate. On December 20, wells 2 and 3 were shut down, and a slow recovery of the water level began in the observation well. In January 1972, well 1 stopped pumping, and the recovery in well 17S/50-36dd increased in rate. Analysis of the data collected through January 1972 showed that wells 7, 8, and 13 had no detectable effect on the water level in Devils Hole; wells 1, 4, and 5 had significant effects; and either well 2 or well 3, or both, had a measurable effect. No direct hydraulic data pertinent to the effect of well 6 had been obtained before it was abandoned. However, reduction of the discharge records of Crystal Pool during the late summer of 1971 show that about 90 percent of the well 6 discharge was compensated by reduction of the flow of Crystal Pool. Because observation well 17 S/50-36dd did not respond as clearly to pumping in the Point of Rocks area as it did to use of wells 4 and 5, an alternative 62.9 [ Wells land 2 on \ 63-0 MAM/”AR \ a“ 2'\\6 Well 3 on \\ d A ll VWV\I\ l9.20 l9_25 632 V. . ll' l> sash 634x— 635 3. L l4 DEPTH T0 WATER,|N FEET BELOW LAND SURFACE DEPTH T0 WATER,lN METRES BELOW LAND SURFACE 6 6 FEBRUARY :lew x /\ 1‘ E 19.60 Well Wax 64.4 r \ 54.5 l8 30l 7 APRIL 64‘3fi DEPTH TO WATERJN FEET BELOW LAND SURFACE DEPTH T0 WATER,IN METRES BELOW LAND SURFACE 49.65 MAY FIGURE 14.—-Segments of the 1972 hydrograph of observation well 17S/51-31dd, showing effects of wells 1, 2, 3, and 17. Dashed segments in upper hydrograph denote extrapolation through periods of no data. path of influence was sought. Well 17S/51-31dd (fig. 7) was equipped with a water-level recorder in January 1972, and subsequently provided an expressive hydrograph. Figure 14 shows the drawdown produced by wells 1, 2, and 3 in February and March 1972. Two new wells (16 and 17 on fig. 7) were completed about 2 mi (3.5 km) southeast of Devils Hole in the spring of 1972. Well 16 proved to be of low yield, but well 17 produced about 2,500 gal/min (about 14,000 m3/d). Well 17 began production in early May 1972. Its effect on the new observation well 17S/51-31dd was immediate and significant (fig. 14). By the end of June 1972, the water level in well 17 S/51-31dd had dropped about 1 ft (30 cm) to 65.5 ft (20 m) below the 32 EFFECT OF PUMPING ON PUPFISH HABITATS IN ASH MEADOWS, NYE COUNTY, NEVADA 2.0 I I l I I r I I if ' l l Acre-feet per month pumped from m 5 wells I,2,3,4,5c|nd I3 07 g Lu . = 3 " - LL I20 355 285 340 (I acre ft I,234m ) E Z 2 5 A I Ll 355 in: 630 I 2 _~ I _ v I v '1 r 1 I l I E E 5% 400 —o.e 33;, '2 < I97I I973 E q 3 3 M. 40 3 3 I 720 ,- o: Sm 30I970 . l . . . . .5oo. . {m o . -0-9 811‘ 1% ‘ I ' W ' ' '7I5'555' ' '4I5 W I I8 I- o 250 380 ‘ 460 o I_ o e U 3. g 03 I972 540 -|.O no >- 3 550 >- d :1 “J 'J m < “3 3 5 I I I I I A I I I f . ‘70 I I <7 0 ' 530 w l I I 0 z - N“ _ ' 2 <3: 58 U1 Acre-feet per month pumped from/ WTWWSZO E 2 05 2 wells I,2,3,l6 and I7 570 4 0 I I I I I I I I I I 1 I I I _ 1-2 ‘ Dec Jan Feb Mar Apr May June »July Aug Sept Oct Nov Dec Jan Feb Mar Apr FIGURE 15.—Mean daily water levels in Devils Hole and approximate monthly pumpage from wells in southern Ash Meadows, late 1970 through early 1973. Dashed segments denote extrapolation through periods of no data. land surface. As with pumping from wells other than 4 and 5 in the Point of Rocks area, the effect of well 17 at Devils Hole is sluggish and not readily apparent. Figure 15 shows the mean daily levels in Devils Hole and the approximate monthly pumpage from the Point of Rocks area from late 1970 through mid-May 1973. The effect of well 17 in early May 1972 is visible. Although the 1972 pumping history was less varied than that in 1971, the total amounts pumped were almost the same: 5,500 acre-ft (6.8 million m3) in 1971 and 5,600 acre-ft (6.9 million m3) in 1972. Figure 15 illustrates that, on the average, the declines for the 2 years are nearly parallel, the hydrograph for 1972 being about 0.5 ft (15 cm) below that for 1971. In late March 1973, wells 1, 2, 3, and 17 were turned on, and the resulting decline in April (fig. 15) is the steepest of record. IMPACT OF INDIVIDUAL WELLS Evaluation of the effects of individual wells is a subjective process. Although wells 4 and 5 produce sharp responses in well 17S/50-36dd and discernible responses in Devils Hole, the longer-term records suggest that they have less effect than wells 1 and 17. The authors assign the following probable effects to individual wells. Wells 1 and 17. —These wells produce the greatest drawdown in Devils Hole during sustained pumping. Their high yields contribute substantially to their effects. Wells 3, 1;, and 5 .-These wells produce significant drawdowns in Devils Hole. The effects of wells 4 and 5 arrive more sharply at Devils Hole than do those of other wells, but the September 1971 recovery suggests that the magnitude may be somewhat less than that produced by the higher yields of wells 1 and 17. Wells 2, 6, 13, and 16'. —These wells have only small effects on the water level of Devils Hole. The discharges of wells 2 and 6 are largely compensated by reduced spring flow; wells 13 and 16, although near wells having greater impact, produce only minor yields. Wells 7 and 8. —These wells have no presently detectable effects on Devils Hole. Well .9.—Because of its location, just more than 1 mi (2 km) southwest of Devils Hole, well 9 is a potential threat to the Devils Hole water level. Through mid-1973, however, it has been used only intermittently to water stock. Table 3 (location 18S/50-11aa) shows that no production test was reported, so the potential impact of well 9 cannot be evaluated. Wells 10, 11, 12, and 14.—There are not sufficient hydraulic observations to evaluate these wells, but their remoteness, small yield, and chemical character suggest little or no effect on Devils Hole. EFFECT ON SPRING DISCHARGE Documenting the reduction of spring discharge, and the consequent threat to pupfish habitats other than Devils Hole, was an important objective of this investigation. Moreover, that part of the total pumpage that is diverted from natural discharge by ——’f OBSERVED EFFECTS OF PUMPING 33 springs to artificial discharge by nearby wells generally affects only details of the local flow subsystem but has little effect on the regional system, including Devils Hole. Reductions of spring discharges were noted during aquifer tests of some of the wells (table 4). Additional data were gained by detailed observation during the 1971 pumping season. Figure 16 shows the 1971 springflow data for four springs in the southern half of Ash Meadows. BIG SPRING The hydrograph of Big Spring during 1971 (fig. 16) shows that the discharge declined slowly from 1,040 gal/min (5,700 m3/d) in January to 920 gal/ min (4,900 m3/d) by mid-October. Although past measurements (table 2) are not significantly different from the January 1971 flow, the decline began in June, which was the beginning of heavy and sustained pumping. In December 1972, the discharge of Big Spring again reached a low of 900 gal/ min (4,800 m3/d), indicating that during 1972 there possibly was a slight accumulated effect of pumping on the discharge of Big Spring. 1 500 JACK RABBIT SPRING The documented effect of well 2 on the flow of Jack Rabbit Spring, and the consistency of the water-quality data with the hydraulic observations, has been discussed earlier in this report. When compared with the 1971 pumping history of well 2 in figure 13, the hydrograph in figure 16 demonstrates this relationship clearly. At several times, such as in mid-April, the hydrograph provided a more detailed record of the pumping periods than did electric-meter readings and field observations. The greatest discharge of Jack Rabbit Spring in 1971 occurred on May 11 and was 425 gal/min (2,320 m3/d), but the hydrograph suggests that continued recovery would have increased this to at least 450 gal/min (2,450 m3/d). This discharge is about 100 gal/min (545 m3/ d) less than previous (1953 and 1962) Geological Survey measurements (table 2) and indicates an effect accumulated during several years of pumping. The expressiveness of the hydrograph in March 1971 shows that well 1 also affects Jack Rabbit Spring, 6000 1000 500 400 300 200 4000 2000 2000 Point of Rocks Springs —————— / """" 1 500 .-——— Jack Rabbit Spring 1000 500 100 DISCHARGE, IN GALLONS PER MINUTE DISCHARGE, IN CUBIC METRES PER DAY 60 Collins Spring JAN FEB MAR APR MAY 40 20 JUNE JULY AUG SEPT FIGURE 16.—— Discharge of selected springs in Ash Meadows. J anuary-October 1971. — 34 EFFECT OF PUMPING ON PUPFISH HABITATS IN ASH MEADOWS, NYE COUNTY, NEVADA although to a much smaller degree than does well 2. In early July a 2-day period of recovery is not as rapid as those typically caused by well 2 and apparently correlates with the temporary shutdown of well 3, shown in figure 13. Using the degree to which the chemistry of the discharges of wells 1 and 3 approach the unique chemistry of water from well 2 and Jack Rabbit Spring as an indication of relative effect, the capture of springflow by well 1 is probably about 50 gal/min (270 m3/d), and that by well 3 may be about 25 gal/min (135 m3/d). Well 2 intercepts the remaining 350 gal/min (1,900 m3‘d) under the pumping conditions of 1971, but it probably is capable of capturing the entire discharge if pumped for sustained periods without interference from other wells. POINT OF ROCKS SPRINGS The group of small springs at Point of Rocks, designated collectively as 18S/51-7dba on table 2, was gaged by 6-inch Parshall flumes on each of two alternate diversion paths carrying their total discharge. In figure 16 the recorded flow is surperimposed on the hydrograph of the responsive Jack Rabbit Spring. The record in figure 16 shows a pattern similar to that of Jack Rabbit Spring, although the variations are less distinct. The fluctuations during March on both hydrographs correlate with a period of intermittent pumping of well 1. In late April irrigation was severely curtailed and did not resume until mid-May. The recovery of the Point of Rocks group is evident, and the flow also reached the 1971 high during this shutdown. This maximum discharge was 385 gal/min (2,100 m3/d), about 35 gal/min (190 m3/d) lower than the reported 1962 flow (table 2). Because of the difficulty of measuring the combined discharge of this group of springs, however, the 8-percent difference may not be significant. After September 9, 1971, when pumping from wells 4, 5, and 6 ended in accordance with the agreement between the ranch and the Federal Government, there was no distinguishable recovery of these springs. Water leaking from a rubber irrigation line distributing water from well 1 made the Point of Rocks record unreliable after mid-October and may be responsible for the apparent increase of flow beginning on September 15; a change in the diversion path also occurred on this date. Difficult channel conditions and the presence of a pump in King Pool, also commonly called Point of Rocks Spring in the literature, prevented continuous measurement of its discharge. Current-meter measurements were made upstream and downstream from its entry into a nearby irrigation ditch. Because the flow of the Point of Rocks spring group usually was channelled into King Pool, further correction was required. The probability for significant measurement errors was high, but the flows shown in table 2 indicate that this spring was not affected by pumping in 1970 nor by the following recovery. COLLINS SPRING The small flow of Collins Spring, located 0.75 mi (1.2 km) south of Devils Hole in SE1/4, sec. 1, T. 18 S., R. 50 E., declined about 5 gal/min (27 m3/d) in 1971 (fig. 16). Although the quantity of loss was small, it did represent a 50-percent reduction of flow. The decline began in July and was recovered after wells 4, 5, and 6 stopped pumping in September, 1971. The pumping history of well 6 (fig. 13), 1.6 mi (2.6 km) west of Collins Spring, provides an apparent correlation with this reduction. CRYSTAL POOL In April 1971, Crystal Pool declined 450 gal/min (2,450 m3/d) in flow after well 6 had pumped at a rate of 900 gal/min (4,900 m3/d) for 1 week. The well apparently developed itself by caving in May, and the discharge rate was increased to 1,370 gal/min (7,470 m3/d). After 2 months of sustained pumping of well 6, the flow of Crystal Pool declined to 1,670 gal/min (9,100 m3/d), a loss of 1,270 gal/min (6,920 m3/d). The total volume of lost springflow could not be compared with the total pumpage because the discharge of Crystal Pool was diverted around the flume before recovery was completed. The interception of Crystal Pool flow is estimated at 90 percent of the pumpage of well 6 for seasons of combined intermittent and sustained pumping. FIVE SPRINGS AREA East of Longstreet Spring, in NW1/4, sec. 23, T. 17 S., R. 50 E., a total of 170 gal/min (925 m3/d) is discharged from a number of small springs and seeps (table 2). The springs are within 500 ft (150 m) of exposures of Paleozoic limestone, and well 7 (table 3), which is in the middle of the spring group, penetrated the limestone at a depth of 48 ft (14.6 m). The 34.5°C (94°F) temperature of well 7 water is the same as that of 3the largest spring, which discharges 75 gal/min (408 m /d). Pumping of well 7 at 530 gal/min (2,900 m3/d) stops most of the spring flow within 1 hour, and sustained pumping captures the entire 170 gal/min (925 m3/d). PURGATORY SPRING During sustained pumping of well 7, a loss of 12 gal/min (65 m3/d) was measured in the discharge of flowing well 17S/50-14cac. Drilled into a travertine spring mound about 0.75 mi (1.2 km) north of well 7, this flowing well normally discharges 20 gal/min (110 OBSERVED EFFECTS OF PUMPING 35 m3/d) from the Paleozoic limestone penetrated from 25 ft (7.6 m) to 92 ft (28 m). In 1972 it was developed as a refuge for Cyp'rinodon diabolz's and named “Purga- tory Spring." LONGSTREET SPRING The location of well 7, about 0.5 mi (0.8 km) east of Longstreet Spring (fig. 7), suggests that it might reduce spring flow significantly. However, only about 360 gal/ min (1,960 m3/d) of the well 7 discharge is not compensated by reduced flow of other springs. Measured discharges of Longstreet Spring (178/ 50-22 aba in table 2) show a variability of about t 10 percent, but comparison with the pumping history of well 7, shown on figure 13, reveals no correlation. The spring discharge is 7°C (13°F) cooler than that of well 7, indicating that the effect of the well, if any, would be manifested subtly over a long period of time, rather than arriving sharply in a short period. There is, of course, a possibility that the November 1971 measurements of Longstreet Spring show some impact of well 7, but subsequent curtailment of the observation program prevented further docu- mentation. ROGERS SPRING The 1971 measurements of Rogers Spring (17S/50-15ab in table 2) show about a 20-percent reduction from earlier Geological Survey measure- ments. Whether the orifice has been changed physically during reworking of the outlet channel system or by traffic on the road immediately adjacent to the spring, or whether this decrease is due to pumping, cannot be stated with certainty. During the aquifer test of well 8 in February 1971, however, Rogers Spring decreased in flow from 590 gal/min (3, 215 m3/d) to 555 gal/min (3, 025 m3/d). The loss was fully recovered within a few days after the aquifer test was completed. SODA SPRING Soda Spring (17S/50-10bcd in table 2) has also apparently lost about 20 percent of its earlier reported discharge, on the basis of highest flow measured in 1971. This 65-gal/min (355-m3/d) flow was completely captured during periods of sustained pumping of well 8 in 1971. ‘ FAIRBANKS SPRING The measurements reported in table 2 for Fairbanks Spring (17S/50-9ad) suggest a lesser reduction of flow (an average of about 10 percent) than is apparent for Rogers Spring and Soda Spring. Although the discharge of Fairbanks Spring decreased from a maximum of 1,580 gal/min (8,600 m3/d) to a minimum of 1,430 gal/min (7,800 m3/d) during 1971, the decline was gradual and could not be correlated with pumping histories. Moreover, during the pumping test of well 8, no reduction of flow was evident on the continuous record of discharge through the Parshall flume. OTHER SPRINGS Several other springs reported in table 2 and located on figure 3 were observed but not examined in detail. Ed L. Reed and Associates (written commun., 1967) reported that McGillivary Spring (17S/50—22ac) flowe'd 155 gal/ min (845 m3/ d), but it was not flowing when visited in September 1970. The condition of the outlet channel, however, indicated that it had flowed in the past, and the reported discharge was compatible with the size of the channel. Cold Spring (17S/50-21ac) had a stable flow during the observed period of October 1970 through April 1971, when pumped diversion for a domestic supply ended the record. The flow was about the same as reported earlier by Ed L. Reed and Associates (written commun., 1967). Three small springs west of Devils Hole in sec. 35, T. 17 S., R. 50 E. continued to flow during 1970 and 1971. The lack of earlier data prevents identification of pumping effects, if any. One of these, School Spring (17S/50—35d1), is developed as a pupfish sanctuary, and its flow has been supplemented by well 18S/50-2aa. The minor flow of School Spring, however, was within the range reported earlier (table 2) and is so small that it is highly sensitive to changes in the orifice. Several springs in the vicinity of the former Davis Ranch (18S/50-11d and 12c) could not be measured because of irrigation-ditch patterns, but their combined flow appears smaller than those reported for 1962 in table 2. The 1962 flows were also smaller than those reported for 1953. Two conical former spring orifices occur in sec. 12, T. 18 S., R. 50 E. east of the Davis Ranch (fig. 3). Sink Spring has a channel indicating former discharge and was reported by Ed L. Reed and Associates (written commun., 1967) to have flowed 25 gal/min (135 m3/ d). Hatchery Spring has no earlier record and the outlet has been destroyed by agricultural leveling. During 1971 the orifice was a pond with a level about 4 ft (1.2 m) below the surrounding land. The pond declined slightly (about 0.1 ft or 3 cm) during aquifer tests of well 5, about 0.6 mi (1 km) to the north, and it has sufficient permeability to accept minor irrigation tailwater. It is difficult to state with certainty whether pumping has reduced the flow of these springs in sees. 11 and 12, T. 18 S., R. 50 E. The records for 1953 and 1962 suggest that natural phenomena, such as gradu- ally evolving diversion of flow to other springs or deterioration of orifice condition, might be responsible for the declines. However, it is evident that the water 36 EFFECT OF PUMPING ON PUPFISH HABITATS IN ASH MEADOWS, NYE COUNTY, NEVADA table has declined at Sink Spring and Hatchery Spring. An alternative explanation is that the discharge of King Pool formerly infiltrated sufficiently to raise the water table and to allow secondary springs to erupt. Diversion of King Pool water for irrigation would have caused the decline of this recharge mound and subsequent decay of the secondary spring flow. It is estimated that the total loss of spring discharge in 1971 not identified as caused by a specific well was between 250 gal/min (1,360 m3/d) and 400 gal/min (2,180 m3/d). The average of 325 gal/min (1,770 m3/d) is considered by the authors to be the best estimate. OTHER SOURCES OF WATER CAPTURE The effects of agricultural pumping on the local hydrologic subsystem and adjacent regional system may be reduced by three factors in addition to the diversion of spring discharge. These factors are: 1. infiltration of pumped water to the ground-water reservoir; 2. reduction of evapotranspiration by lowering the water table locally around the wells; and 3. reduction of evapotranspiration by clearing fields. For these factors to be effective in making the net well-field discharge less than the gross pumpage, however, they must act at positions in the system that retard a general and sustained lowering of the water table in the well field. EFFECT OF WATER-TABLE DEPTH Ash Meadows can be divided (fig. 17) into eastern and western sections having significantly different hydrologic characteristics. From the highlands of the Paleozoic outcrops, where the water table is generally from a few tens to many tens of feet beneath the land surface, the land slopes westward more steeply on the average than does the water table. The springs that occur close to the hills in eastern Ash Meadows are generally warm, 32°C (90°F) or higher, and relatively small. The exceptions are King Pool, which discharges about 1,200 gal/min (6,500 m3/d), and Longstreet Spring, with a similar discharge but the significantly lower temperature of 27°C (81°F). Around the spring orifices and along the outlet channels phreatophytes and evaporation consume the total discharge of all the springs except Longstreet Spring and King Pool. The westward slopes of the land surface and the water table in eastern Ash Meadows intersect generally along a line connecting the other major springs (fig. 17). West of this spring line the water table is at or within a few feet of the land surface, and recharge water applied to the land by irrigation or by spring flow from eastern Ash Meadows is generally rejected by the shallow ground-water reservoir. Instead, it evaporates, is consumed by the dense phreatophyte growths, or runs off to Carson Slough. The spring line, if defined only on the basis of rejected recharge, should be carried eastward to King Pool between Crystal Pool and Jack Rabbit Spring, as shown in figure 17. The former discharge of the Davis Springs, however, favors the westward position of the line for stratigraphic reasons. Exploratory drilling indicates that the valley-fill sediments are much less permeable in western Ash Meadows than are those east of the spring line. With the exception of well 10, which produces a moderate discharge of very poor quality, productive wells are confined to eastern Ash Meadows. Evidence presented later suggests that faults define the spring line, but this conclusion is not necessary to support the observation that none of the factors compensating well discharge can be effective in western Ash Meadows. Because of the proximity of the water table to the land surface, no reduction of consumptive water use nor application of additional water can raise the water table significantly west of the spring line. The spring line, therefore, is effectively a hinge about which the water table in eastern Ash Meadows may rotate, but along the line and to the west the water table may not build up. In addition to reduced spring flow, the infiltration of pumped water and salvage of evapotranspiration in eastern Ash Meadows may be deducted from gross pumpage to determine the net withdrawal of ground water in excess of natural discharge. DEFINITION OF PUMPING UNITS Figure 17 shows further divisions of eastern Ash Meadows into five pumping units. Unit A, which extends northward into the wide valley east of Devils Hole, contains production wells (1, 2, 3, 16, and 17) that are variable in chemical quality and, where not compensated by reduced spring flow, produce a slow but persistent drawdown in Devils Hole. Unit B has two major wells (4 and 5) producing water of quality very similar to that of Devils Hole. Drawdown from pumping these wells arrives distinctly at Devils Hole. The separation of unit C from unit B may arise only from the lack of data from unit C. The discharge of well 6 is compensated by reduced flow from Crystal Pool, and no other wells exist in the unit. Water temperature and quality in this unit, however, suggest a close hydraulic relationship with the lower carbonate aquifer. Consequently, future wells would probably lower the water level in Devils Hole. Unit D has only one well (well 7) and minor spring discharge (about 170 gal/min or 925 m3/d). This —7— , 37 OBSERVED EFFECTS OF PUMPING EXPLANATION Production well 30ch E 4. ' ' '00 Other wen I fifiogers Spring Mecca Flowing well "" S r'n 5l4ccc , p ' g M Paleozoic ouicrop Longstreet Spring Vb -: 0' 3 2 a: g é ‘1} \ ~ a / T. I? 3. ¢ ; T. l8 S. . P°°' Collins '- Q \ ~ Spring ’ g \ Ur‘m ‘ t. o ‘09 B / 0 \ é \ ?~ m c ~‘F \ ' O O. N. Davl's ® y. Springs \ j‘\ . Spring line ‘ Spring 0 I 2 MILES \ F I 1 I 4| . o I ZKILOMETRES um \ U0” 0 _' A m We of 0: ”Big Spring l ‘ FIGURE 17.—Location of the spring line and pumping units in Ash Meadows. 38 EFFECT OF PUMPING 0N PUPFISH HABITATS IN ASH MEADOWS, NYE COUNTY, NEVADA discharge is similar in temperature and chemistry to Devils Hole water. The temperature of discharge from both wells and springs in pumping unit E suggests that the probability of significant effects on Devils Hole is remote. However, the close chemical similarity of the spring discharge to Devils Hole water points clearly to the lower carbonate aquifer as the regional source, and it would be imprudent to rule out completely an eventual effect of increased pumpage from this unit. CAPTURE OF EVAPOTRANSPIRATION Reduction in the use of water by phreatophytes within the cone of depression around the wells is difficult to establish because of the complexity of the hydraulics in this area. Field examination indicates that it is small compared to the other sources of water capture, for phreatophytes are only sparsely dis- tributed near most of the wells. Eradication of phreatophytes to clear fields east of the spring line, however, is potentially a significant factor affecting the net withdrawal from the Ash Meadows discharge area at the 1971 stage of ground-water development. Wells 1, 2, and 3, as a group or singly, dry up 20-30 acres (80,000-120,000 m?) of seepage that evaporates and supports dense mesquite and saltgrass growth below the spring group at Point of Rocks. Not more than 150 acre-ft (190,000 m3) was captured in pumping unit A in 1971. The actual amount is probably less, as the drawdown over this area at the peak of the pumping season was not more than a few feet, and water was still within reach of the mesquite. In unit B, wells 5 and 13 are situated on relatively high ground that is only sparsely covered with vegetation and are assigned no capture of evapo- transpiration. The effect of well 4 is less certain, although none can be demonstrated. The clearing of phreatophytes from nearby fields probably has made this a moot point. About 10 acres (40,000 m2) of dense mesquite and grasses between well 6 and Crystal Pool, and thus not watered by the emergent flow of Crystal Pool, may be affected by pumping. Together with seepage at the ground surface on about 2 acres (8,000 m2), a potential gain of about 60 acre-ft (74,000 m3) per year exists here. Under the pumping conditions of 1971, the net withdrawal from unit C was probably compensated entirely by salvage from spring discharge and evapotranspiration. The dense growth of mesquite, saltgrass, saltbush, and other phreatophytes in pumping unit D below the springs in the vicinity of well 7 probably are watered entirely by recycling of the spring water. Consequently the salvage is taken into account under spring-flow reduction. Well 8 has minor acreages of saltgrass and meadow grass within its possible zone of influence in unit E. Most of this, however, merely intercepts surface water in channels on its way to the low meadows west of the spring line. The clearing of fields causes a substantial reduction of evapotranspirative withdrawal east of the spring boundary. The coverage of phreatophytes on this land was estimated by comparison with nearby undeveloped land. Water-use rates were estimated with the assumption that only transpiration was stopped; evaporation from the soil should have remained the same or increased beyond the cones of depression of the wells. The fields east and southeast of wells 1 and 3 that have been cleared and are partly planted with Bermuda grass were, in the natural state, covered with sparse saltgrass, mesquite, and healthy sagebrush. Based on rates of use estimated by RE. Rush (written commun., 1970) for southern Clark County, Nev., the average rate of use for dense coverage of such vegetation would be on the order of 5 ft (1.5 m) per year (an abbreviated form of acre-feet per acre per year). A generous estimate of the natural cover density is 20 percent, and the height of growth was probably less than optimum. Consequently the salvaged evapotranspiration does not exceed 1 ft (0.3 m) per year over the approximately 600 acres (2.4 million m2) of cleared land. The maximum annual salvage of 600 acre-ft (740,000 m3) is assigned to pumping in unit A, which in 1971 provided all well water applied to these fields. An additional 48 acres (194,000 m2) at wells 1, 2, and 3 was probably more densely covered with mesquite, sagebrush, and saltgrass. An estimated use rate of 3 ft (0.9 m) of water over this area suggests a saving of about 150 acredft (185,000 In 3) each year. Combined with the fields to the east, about 750 acre-ft (925,000 m3) per year can be deducted from pumpage in Unit A that is applied there. Between Point of Rocks and the Davis Springs in pumping unit B, about 220 acres (890,000 m2) formerly supported luxurious growths of mesquite and willows along the discharge channel of King Pool and moderately dense mesquite, sagebrush, saltbush, and saltgrass away from the channel. This area probably has been dried by diversion of King Pool water, but, to avoid underestimating salvage, a ground-water consumption rate of 2 ft (0.6 m) is applied to the 200 acres (810,000 m2) having moderate coverage, and a saving of 400 acre-ft (494,000 m3) might have been achieved by clearing of these fields. Although the discharge of wells 4, 5, and 13, combined with the flow of King Pool is more than adequate to irrigate this OBSERVED EFFECTS OF PUMPING 39 acreage, pumpage from Unit A was used to supplement King Pool after wells 4 and 5 were shut down in September, 1971. The addition of wells 16 and 17 in 1972 created a surplus of water in unit A (at the 5 acre-ft per acre or 1.52 m3/m2 per year alloted by the State Engineer for southern Nevada), and diversion to unit B continued. All fields that have been cleared of phreatophyte growth and watered from pumping unit C (well 6) are in western Ash Meadows. Therefore, no salvage is allotted from clearing fields in unit C. About 60 acres (240,000 m2) between Longstreet Spring and well 7 in unit D were formerly covered with a moderate growth of mesquite, sagebrush, and saltgrass. This is believed to have been watered by spring flow emerging near well 7 and completely captured by pumping of that well. Even if this is in error, not more than 300 acre-ft (370,000 m3) is saved annually. Fields cleared east of the spring line in unit E are restricted to about 100 acres (405,000 m2) of sandy uplands west and northwest of Longstreet Spring. The pre-agriculture coverage of these fields is not known, but phreatophytic use of water away from the outlet channels of Longstreet Spring and the former McGillivary Spring is believed to have been minor. RECHARGE BY INFILTRATION Early in 1971 about 200 acre-ft (250,000 m3) pumped from well 1 into a leaky reservoir northeast of Point of Rocks infiltrated with little evaporative loss. An estimated 30 percent of the 130 acre-ft (160,000 m3) pumped from well 8 into a reservoir on Carson Slough east of Rogers Spring also re-entered the ground-water reservoir. This recycled water is not considered in the following estimate of infiltration through irrigated fields. Recharge from precipitation at elevations below 4,000 ft (1,220 m) in the arid basins of southern Nevada is negligible, according to Maxey (1968). Walker and Eakin (1963) estimated the annual recharge to the Amargosa Desert from precipitation falling within the topographic drainage basin to be about 1,500 acre-ft (1.85 million m3), all of this occurring in zones having 8 in (200 mm) or more of precipitation per year. Soil saturation by the more intense application of irrigation water, however, may destroy capillary forces in the formerly unsaturated zone, thus allowing infiltration to occur in zones having less than 8 in (200 mm) of applied moisture. No direct observations are available for use in ' selecting the percentage of water applied that might infiltrate in fields east of the spring line. Visual estimates of tailwater runoff and the probable use by crops and evaporation from the soil suggest that not more than 30 percent of the pumped water re—enters the local ground-water system. This is thought by the writers to be an upper limit and probably unrealistically high. The total pumpage from unit A that was applied to fields east of the spring line in 1971 was 3,870 acre-ft (4.8 million m3). If a rate of one-fourth of the pumpage is used, almost 1,000 acre-ft (1.2 million m3) would have infiltrated. About 40 percent of the pumpage from unit B was transported west of the spring line, resulting in a net useful infiltration of 18 percent of gross pumpage, or about 240 acre-ft (300,000 m3). All withdrawals from units C (well 6) and E (well 8) are applied west of the spring line. About 150 acre-ft (180,000 m3) of the discharge of well 7 is recovered in unit D. OVERDRAFT OF LOCAL SUBSYSTEM IN 1971 The possible sources of salvage of pumped water are summarized by well and by pumping unit in table 8. Subtracting these savings, including the long-term declines in Big Spring and the springs in unit B, from gross pumpage gives the 1971 overdraft (excess of total discharge over natural discharge) for each pumping unit. The estimated overdrafts for units A and B are minimum values, for all salvages were estimated at their upper limits. The net pumpage shown for unit E may be high, for the long-term reduction of the flows of the springs has (not been subtracted. If the apparent long-term decreases in Fairbanks, Soda, Rogers, Longstreet, and McGillivary Springs, as shown in table 2, are TABLE 8.—Estimated capture of water pumped from wells and overdraft from pumping units in 1971 Pum in Well Gross Percent captured from use: un‘i’t g no. (hug-f5)? Springs Drawdown2 Infiltration3 {sens-£53 A ..... , 1 1,800 6.7 3.9 30 1.070 A ...... 2 870 45 3.4 30 190 A ...... 3 1,200 4.6 4.2 30 740 Transpiration captured by clearing fields ............. -750 Long-term spring flow decline ....................... _-1m_ OverdraftfromunitA........................'..1,150 B ....... 4 490 . . . . . . 18 400 B ....... 5 790 . . . . . . 18 650 B ....... 13 70 . . . . . . 18 60 Transpiration captured by clearing fields ............. -400 Long-term spring flow decline ....................... -280 Overdraft from unit B .......................... 430- C ....... 6 450 90 10 . . . 0 D ...... 7 480 33 . . . 30 180 E ...... 8 440 20 . . . . . . 350 Capture of transpiration and long-term spring flow ..... _.Q__ Overdraft from units C, D, and E ................ 530 1Rounded to nearest 10 acre-ft. Infiltration beneath reservoirs deducted from pumpage of wells 1 and 8. 2Evapotranspiration captured by drawdown zone around well. 330 percent of water applied east of spring line assumed to infiltrate. 40 EFFECT OF PUMPING 0N PUPFISH HABITATS IN ASH MEADOWS, NYE COUNTY, NEVADA accurate, they total about 570 gal/min (3,100 m3/d) or 920 acre-ft/yr (1.1 million m3/yr). This is more than twice the average annual pumpage from well 8 and significantly greater than combined pumpage from wells 7 and 8 that is not otherwise compensated by observed reductions of spring discharge. Obviously pumping from wells operated by the Spring Meadows Ranch has not salvaged the entire long-term reduction, and it is unlikely that it has salvaged a significant part. The overdraft during 1971 from units A and B was at least 1,580 acre-ft (1.9 million m3) or a 9-percent additional load on the total discharge from the Ash Meadows ground-water system. Because of the liberal estimates of salvage, the overdraft might have been twice that amount. SOURCE OF OVERDRAFT Lohman (1972, p. 63), in summarizing C.V. Theis’ (1940) discussion of the source of water derived from wells, stated: Prior to development by wells, aquifers are in a state of dynamic equilibrium, in that over long periods of time recharge and discharge virtually balance. Discharge from wells upsets this balance by producing a loss from storage, and a new state of dynamic equilibrium cannot be reached until there is no further loss from storage. This can only be accomplished by: 1. Increase in recharge (natural or artificial). 2. Decrease in natural discharge. 3. A combination of 1 and 2. As of 1972, based on annual low water levels in Devils Hole, the upset of this balance produced by pumping in Ash Meadows was still producing a loss in storage, and equilibrium had not been re-established. The easily salvaged flow of Jack Rabbit Spring and the reduction of phreatophytic use of water, the two most significant sources of salvaging pumping from units A and B, have been realized fully or almost fully. The decline of the water table, and of potentiometric head in the confined aquifers at depth, must continue until additional natural discharge is captured, or until the 4,500-mi2 (about 12,000-km2) Ash Meadows ground- water system expands its boundaries to capture 10 to 20-percent more recharge. In either case water levels throughout the local subsystem and in the adjacent lower carbonate aquifer, including Devils Hole, must continue to fall. Figure 18 illustrates that not all reduction of spring discharge is effective in reducing the threat to the Devils Hole pupfish. Wells that affect springs easily (fig. 18A) may indeed salvage the spring flow. In the complex geologic setting of Ash Meadows, however, more remote pumping may find that its easiest path of communication with the spring (fig. 183) is along a longer but more permeable path through the regional lower carbonate aquifer. In this case the reduction of spring flow may help prevent an overdraft in the overall regional system but, nevertheless, it produces drawdown in Devils Hole. Although figure 18 is schematic and generalized, it is closely similar to conditions presently believed to exist in Ash Meadows. The spring shown is similar to Crystal Pool, and the well in figure 18A represents well 6, which probably did not affect the water level in Devils Hole. In figure 183 the remote diversion of water is similar to the effects of the wells in unit A ( 1, 2, 3, 16, and 17). The late 1971 and later effects of pumping these wells strongly suggest that their recent apparent influence (E.L. Reed, oral commun., 1973) on the flow of Crystal Pool has been transmitted northward into the regional aquifer east of Devils Hole and then west to Crystal Pool. To reduce the flow of Crystal Pool, which lies on the spring line, or the “hinge” for the eastern Ash Meadows water table, it must first lower the water table in the lower carbonate aquifer, thereby causing drawdown in Devils Hole. SAFE YIELD As pointed out by Lohman (1972), the term “safe yield", or its close equivalent “perennial yield”, has as many definitions as definers. He credits Meinzer with probably having first defined safe yield as “the rate at which the ground water can be withdrawn year after year, for generations to come, without depleting the supply * * * ” (Meinzer, 1920, p 330). Since 1920 the term has been redefined innumerable times and with such a wide variety of meanings that it no longer has meaning. All of these ultimately reduce to the “grass roots” definition of Lohman (1972, p. 62), who has stated that safe yield is “the amount of ground water one can withdraw without getting into trouble." According to this definition, even a planned period of mining ground water from storage to develop the economic base for importing water later, as proposed by Maxey (1968), would be compatible with the safe-yield concept provided that all parties affected by the overdraft had previously agreed. However, as small ground-water systems attempt to establish a new equilibrium under heavy pumping stresses, they may expand their boundaries so as to injure water rights existing in adjacent systems. When only. the availability of water for domestic, industrial or agricultural use is considered, still the decision for a planned overdraft may not be a local one. In an era of environmental concern, where the supply for immediate human use is increasingly subordinated to sustained use for generations to come, Meinzer’s (1920) original definition of safe yield seems OBSERVED EFFECTS OF PUMPING 41 to be becoming increasingly appropriate again. Walker and Eakin (1963, p. 28) defined perennial yield as “the maximum amount of water that can be withdrawn from the ground-water system for an indefinite period of time without causing a permanent depletion of the stored water or causing a deterioration in the quality of the water.” They further estimate that the perennial yield of the Amargosa Desert, of which Ash Meadows is a part, as tentatively about 24,000 acre-ft (30 million m3) per year. Of this “about 17,000 acre-ft [21 million m3] can be obtained by full development of the springs at Ash Meadows. The remaining amount would be available for development by wells largely in the area northwest and northeast of the springs.” (Walker and Eakin, 1963, p. 29.) Note that the total discharge of the Ash Meadows area, as defined in this report, is limited essentially to the spring discharge. 4. Local water levels decline 3.Diversion from local aquifer 6. Spring level falls below outlet .1 ._..— _..—- _.— ...—— J: 5. Spring discharge reduced or stopped; flow in aquifer may reverse 2. Spring position controlled by fault or stratigraphic change i A. 6. Elevation of spring discharge nearly constant reduced 4. Wdter elevation and gradient 7. Water level in regional aquifer not affected unless diversion exceeds reduction of natural discharge. or ....l I: 3....“ -" \:—--\_ I 5. Spring discharge I decreases 2. Spring position controlled by fault or stratigraphic change 8. 1. Local aquifer 3_ Remote diversion from regional ”fl / FIGURE 18.—C0mparison of the effects on spring discharge and the water level in the regional aquifer when pumping is (A) close to and (B) remote from the spring. \ 42 EXAMINATION OF ALTERNATIVE CAUSES The possibility that other causes have produced the drawdown in Devils Hole is very remote, but it should be examined briefly. Pumping from the Ash Meadows ground-water system at the Nevada Test Site totalled about 20,000 acre-ft (25 million m3) from 1951 through 1971 (Claassen, 1973), an average of about 1,000 acre-ft (1.25 million m3) annually. Most of this has been produced from wells in the lower carbonate aquifer or in overlying Cenozoic units that are sources of recharge to the regional flow system. Production records and periodic water-level measurements presented by Claassen (1973), however, show that the peak production was in the early to mid-1960’s and that there is not yet a measurable effect on water levels in the regional aquifer beneath the Nevada Test Site. The water levels in Geological Survey experimental wells located between the Nevada Test Site and Ash Meadows (sampling point 3 on fig. 11) remained stable from 1966, when measurements began, through 1969. By September 1973, however, the levels had declined about 1 ft (30 cm), suggesting that the drawdown at Ash Meadows had spread at least 8 mi (13 km) to the northeast. These wells are developed in the Bonanza King Formation, the limestone in which Devils Hole is formed. The stability of water levels in the lower carbonate aquifer cited above also discounts long-term reductions of recharge as a possible cause. In addition, according to the US. Fish and.Wildlife Service Desert Game Range (Refuge Manager, oral commun., 1971), the Spring Mountains, during the winter of 1968—69, received their heaviest precipitation in 40 years. Figure 2 shows no effect of this on the Devils Hole hydrograph. Elastic changes of the aquifer storage volume by earthquakes and nuclear explosions have been recorded by the hundreds as short-term, oscillating water-level changes in Devils Hole, but permanent offsets of the stage record have not been observed. Most effective in precluding these other factors as causes for the decline in Devils Hole and the reduction of spring discharge, except for those springs in pumping unit E, is the positive correlation of the Devils Hole hydrograph and recorded spring flows with the detailed pumping record obtained in 1971 and generalized pumping schedules since 1967. The reduced flow of the large springs in northern Ash Meadows (pumping unit E) indicates the possibility that pumping in the Amargosa Farms area northwest of Ash Meadows has diverted some water from the Ash meadows ground-water system into the Pahute Mesa system (fig. 4). If this is in fact true, it EFFECT OF PUMPING 0N PUPFISH HABITATS IN ASH MEADOWS, NYE COUNTY, NEVADA illustrates that the dynamic equilibrium in ground- water flow is not confined to a single flow system. In its effort to re-establish equilibrium by capturing enough additional recharge to satisfy overdrafts, a ground-water system will expand its boundaries, thereby passing the overdraft on to its neighbors. Measurements of the springs in northern Ash Meadows have not been frequent enough to define the variations in discharge. Estimates of pumping in the Amargosa Farms area, abstracted by the Office of the Nevada State Engineer (written commun., 1970), show that pumping reached its maximum in the mid-1960’s and has declined to a minor amount since then. The effect on the Ash Meadows ground-water system may indeed be recovering now, but only additional years of measurements can verify this. MOVEMENT OF GROUND WATER IN ASH MEADOWS AREA NATURE OF THE REGIONAL FLOW SYSTEM Local details of the flow system and actual rates of movement are difficult to establish in carbonate aquifers. Although the hydrogeology approaches a level of homogeneity when considered on a gross scale, it appears quite capricious as the area of observation is decreased. The irregular development of secondary perme- ability by chemical solution is responsible for this unpredictability. Three factors are dominant in controlling the geometry of solution-channel growth. The first is the areal pattern of recharge. Second is the position and orientation of structural discontinuities (faults and joints), which initially provide a secondary permeability that is commonly several orders of magnitude greater than that in the primary interstices. The third is the position of the discharge area, for the drain system which develops must eventually deliver the water where it can be expelled from the system. The existing paths of fracture permeability receive seepage from the far reaches of the basin and focus it upon the discharge area. This geometric requirement provides a corollary that the flow must become larger and more concentrated along the paths from the recharge areas to the discharge points. Consequently, the paths tend to combine into fewer but more open conduits as they approach the discharge area. Because the ability of fractures to transmit water increases approximately as the square of their width, the more open fractures grow into conduits much more rapidly than the smaller ones. The result is that flow is concentrated into a few master conduits at the discharge areas (fig. 19) and in places within the basin MOVEMENT 0F GROUND WATER IN ASH MEADOWS AREA 43 Areas with less than average recharge Areas with greater than average recharge Range of permeability Ground-water divides within basin - Path of greatest hydraulic connection between A and 3 FIGURE 19.—Concentration of flow in a carbonate aquifer from many paths of low permeability into a few highly permeable conduits. where flow is constricted to narrow zones by geologic conditions. In this sense, even artesian flow systems in carbonate rocks resemble surface river systems par- ticularly those in which rock-fracture systems affect the geometry, although ground-water systems are three-dimensional. One distinct and very important difference, however, is that surface drainages are discrete entities, in which tributary branches contribute to the flow of only one trunk. In a ground-water flow system the master conduits may share secondary trunks, which in turn share lesser tributaries. Because the smaller tributaries are not discrete to a single subsystem, hydraulic interference between subsystems is to be expected. Interference effects are usually difficult, if not impossible, to predict in detail; however, they may require transmission upgradient in the first subsystem to the point where there is good hydraulic connection with an adjacent subsystem. Figure 19 shows schematically, in two dimensions only, how the easiest path of communication between conduits leading to different discharge points may be much longer on the map than the mere distance between the points. Because numerous paths of varying hydraulic conductivity are available, the effect of pumping at point A will be dispersed and will arrive at point B in a complex manner. Although schematic in intent, this illustration is similar in important ways to the hydraulic geometry in the vicinity of the Ash Meadows springs and the flow path approach from the east. The upward movement of warm water at Ash Meadows from deep within the regional system, however, adds the three-dimensional aspect that further complicates the natural system. FLOW IN THE LOCAL SUBSYSTEM The development of the Spring Meadows well field, and the observed effects of pumping, provided an opportunity that was not available for earlier workers to examine some of the details of flow in the local subsystem. The complexity of the local aquifers has been mentioned several times previously in this report. In this section the water-quality data, the hydraulic-test data, and the observed effects of pumping will be combined with geologic observations to explain the pattern of flow from the regional aquifer to the points of discharge by springs. EVIDENCE FROM WATER CHEMISTRY AND TEMPERATURE Percentages of the major chemical constituents of the Water samples are shown in table 6 and on the quadrilateral plot in figure 20. Starting with the sample (6) from Army well 1 near the Nevada Test Site, most of the analyses show a progressive enrichment in sodium over the sum of calcium and magnesium and a lesser enrichment of other anions (mainly sulfate) over bicarbonate plus carbonate. Sample 6 'is thought to represent the chemical quality of water shortly after entering the flow system from the Spring Mountains. By the time it is released to the local subsystem, however, the composition has evolved to that of Devils Hole (sample 42) and the 17 samples represented by the bold circle in figure 20. Where the water is forced to travel considerable distances to points of discharge after release from the regional aquifer, its composition follows essentially the same progression through sample 60 (Crystal Pool) and sample 99 (Big Spring) to sample 102 (Bole Spring). It is significant, however, that the 1966 sample (96) from Jack Rabbit Spring and the samples from all springs except Soda Spring (sample 15) in pumping unit E of northern Ash Meadows fall in the bold circle although they are distant from outcrops of the lower carbonate aquifer. 44 EFFECT OF PUMPING ON PUPFISH HABITATS IN ASH MEADOWS, NYE COUNTY, NEVADA It is instructive to examine the samples represented by the bold circle. They fall into five groups, identified by general location and temperature. Two of the samples are from wells developed in the lower carbonate aquifer at depths of about 600 ft (180 m) several miles northeast and east of Ash Meadows: Sample 3, Geological Survey tracer well 2, 305°C (87°F); Sample 54, well 17S/50-08c1, 28°C (82°F). Four of the samples are from three large springs and one slightly flowing well in northern Ash Meadows: Sample 12, Fairbanks Spring, 27°C (81°F); Sample 21, Rogers Spring, 28°C (82°F); Sample 24, well 17 S/50-15ad, 19.5°C (67°F); Sample 30, Longstreet Spring, 28°C (82°F). Nine samples are from springs and wells in or very close to the outcrops of Paleozoic carbonate rocks: Sample 33, spring 17 S/50-23bbc, 33.5°C (92°F); Sample 36, well 7, 34.5°C (94°F); Sample 45, well 17S/50-36dd, 33.5°C (92°F); Sample 69, well 5, 315°C (89°F); Sample 72, well 13, 30.5°C (87°F); Sample 75, well 4, 30.5°C (87°F); A, 7% EXPLANATION i (DISSOLVED souosnw MILLIGRAMS PER LITRE) o O 00 O o O O 09 9 m L_-_......|__|_L_i Diameter of circle O >¢ 78 Sample number on table 6 *Cenfer of bold ccrcle plotted at oveva ge composition. Actual range: Ca+Mg = 561'? percent; HCO‘,’+OO3 = 6912 percent FIGURE 20.—Percentage reacting values of dominant ions in water samples from wells and springs in Ash Meadows and vicinity. Sample 87, Indian Rock Spring, 33.5°C (92°F); Sample 90, Point of Rocks spring group, 31°C (88°F ); Sample 93, King Pool, 32°C (90°F). The last two samples in the grouping are: Sample 57, well 6, 31°C (88°F); Sample 96, Jack Rabbit Spring (1966), 28°C (82°F). The first group appears to represent water which has adjusted to a state of equilibrium with the carbonate aquifer and which follows shallow flow paths toward northern Ash Meadows. By the time it arrives at Ash Meadows the water is at a temperature of 28°C (82°F). Where it can escape at high rates through a short and permeable path, such as at Longstreet and Rogers Springs, it emerges at the surface essentially unchanged in temperature or chemistry. The larger discharge of Fairbanks Spring probably has a much longer path through Cenozoic deposits, for it cools slightly and adds a slight amount of boron not present in the other samples. The largest group of water samples, taken from and near the Paleozoic rocks, display an equally stable composition, but their greater temperatures indicate approach to Ash Meadows through the deeper part of the regional flow system. Where it is discharged at high velocities through a path of even more than a mile (about 2 km) in length, such as at Crystal Pool and well 6, it changes little in character. If the discharge velocity is somewhat less or if the local aquifer is shallower, the water cools but still retains its basic chemical composition, as did the discharge of Jack Rabbit Spring before development of the well field. Figure 20 also illustrates that the three samples (27, 39, and 63) taken from west of the spring line (fig. 17) are enriched in sodium, but not in sulfate, with respect to the composition of water in the carbonate rocks. This tends strongly to support the reliance placed by the authors on the function of this line in the earlier discussions of water salvage and pumping overdraft from Ash Meadows. Sample 15 from Soda Spring, sample 18 from well 8, and sample 27 from the unused well 14 group closely with the samples from the Pahute Mesa ground- water system, although the latter are lower in total dissolved solids. The silica contents of Soda Spring, well 8, and well 10 (sample 39) further indicate that, west of the spring line and along the spring line in pumping unit E, water typical of the Pahute Mesa system may be mixed during discharge with that typical of the Ash Meadows system. Waters of the different compositions may in fact come from discrete aquifers at different depths. If this is the case, the subsurface flow paths may indeed resemble a multi-level freeway interchange. 2 MOVEMENT OF GROUND WATER IN ASH MEADOWS AREA There remain five samples that require discussion. With their temperatures these are: Sample 51, well 17S/51-31dd, 25.5°C (78°F); Sample 78, well 1, 28°C (82°F); Sample 81, well 2, 26.5°C (80°F); Sample 84, well 3, 295°C (85°F); and Sample 96a, Jack Rabbit Spring (1970), 25.5°C (78°F). Water from the low-yield well 17S/51-31dd is very similar in composition to the samples from the Pahute Mesa system (fig. 20). Its chemistry is apparently determined primarily by the silicate minerals in the lower elastic aquitard, which crops out in the unnamed range east of the well. The close similarity between the samples from well 2 and Jack Rabbit Spring in recent years has been discussed earlier. Examining the nature of the change in Jack Rabbit Spring, however, may provide some insight into the reason for the change. Dividing the total ion concentration (in milliequivalents per litre) of the 1970 sample with that of the 1966 sample reveals that the total ion concentration increased by a factor of 4.8. The enrichment factor for individual ions can similarly be determined and then divided by 4.8 to give the relative enrichment factors following: Ga 0.73 Na 1.3 H003 0.21 F 0.24 Mg .93 K .56 804 2.6 N03 60 1 Sr .94 Li .48 CI 3.2 It is evident that among the cations sodium has been enriched by the greatest factor and that this has been essentially at the expense of calcium. The contents of potassium and . lithium are too small to have contributed significantly. Among the anions, nitrate, chloride, and then sulfate have become relatively more abundant, with a large loss of bicarbonate. The samples of typical water in Ash Meadows are nearly saturated with respect to the bicarbonate ion, as indicated in table 6 by the common loss of bicarbonate from unacidized anion samples. Analyses for calcium in these anion samples showed an attendant loss of calcium. Bicarbonate could not have been enriched as the character of Jack Rabbit Spring water changed, and the 1970 analysis shows that it is still saturated. There are at least two possible sources of this contamination that are consistent with the agricultural activities. The first is connection, by the drilling of well 2, of an aquifer containing brackish water with the aquifer connecting well 2 with Jack Rabbit Spring. The brackish-water aquifer would have to be of higher potentiometric head to cause flow up the well bore and displace the normal water in the Jack Rabbit aquifer. Secondly, the addition of gypsum and fertilizers by infiltrating irrigation water could 45 explain the increase of sulfate and nitrate and the small decrease of calcium relative to that of bicarbonate. This would not, however, explain the enrichment of sodium and chloride. It is entirely possible that both mechanisms have acted simultane- ously. The compositions (fig. 20) and temperatures of water from wells 1 and 3 suggest mixing of normal carbonate waters with that from the now-contamin- ated Jack Rabbit aquifer. EVIDENCE FROM HYDRAULIC TESTING Although the transmissivities and storage coeffi- cients determined from type-curve solutions of drawdown and recovery data were given in table 4, there was little discussion other than to caution against using them quantitatively. For evaluating the aquifers quantitatively, they appear to have little use in this area. Although the deeper aquifers in the local subsystem are artesian and probably well confined by thick, relatively impermeable lakebeds, the shallow zones were obviously being partly dewatered whenever cascading occurred in the wells. For wells of these depths (300-800 ft, or 100-250 m) and lithology, storage coefficients greater than 10'4 would be uncommon if the aquifers were indeed confined and not dewatered. 0n the other hand, if 10 percent of the discharge came from unconfined or dewatered aquifers having a porosity of 20 percent, an effective storage coefficient, Seff= (0.9) (104) + (0.1) (0.20-Sr), might be determined, where Sr is the specific retention, or the porosity resisting gravity drainage within the period of observation. Because Sr rarely exceeds a few hundredths except in clays, it is evident that storage coefficients will generally be dominated by the unconfined portion. An alternate explanation is required if we assume that the transmissivity is concentrated primarily in confined aquifers with intercalated clay and silt beds. The quality of the data matches with the delayed-yield type curves (or with those for partial penetration which give almost identical results) suggests that this assumption may be justified. Although well 1 drew down as much as 70 ft (21 m) during the March 1971 tests, the casing is not perforated above a depth of 155 ft (47 m). It is highly unlikely, therefore, that dewatering occurred except in the immediate vicinity of well 3, which had minor cascading from a zone 12 ft (3.7 m) beneath the surface during testing of well 1. The large storage coefficient of 4X10'2 determined from observations in well 2 apparently reflects a lack of good hydraulic connection between the two wells. The effect of pumping arrived later than it would have in a homogeneous, extensive aquifer. Because the 46 cone of depression grows preferentially along paths of the greatest hydraulic conductivity, the drawdown at poorly connected observation wells is correspondingly low, resulting in transmissivities that are too high. This, in turn, adds to the error in the storage coefficient. Transmissivities calculated from pumping-well data, or estimated from specific capacities, do not exceed 8,800 ft2/d (820 m2/d). This suggests that falsely high transmissivity values, resulting from the lack of hydraulic isotropy, were calculated from observation-well data. Transmissivities determined from measurements in pumped wells are affected by well losses and are usually considered inferior to those calculated from measurements in observation wells. However, this generalization is true only where aquifers are continuous and uniform between the pumped well and observation wells. Because of the complexity of the local aquifer system in Ash Meadows, pumped-well data probably provide the more realistic estimates of transmissivity. Because of the varied pumping histories of wells in southern Ash Meadows in 1971, it was possible at certain times to use nonpumping production wells as observation wells during pumping tests of other mZ/d 2 n /d lo4~ 105 LOG SCALE EFFECT OF PUMPING 0N PUPFISH HABITATS IN ASH MEADOWS, NYE COUNTY, NEVADA production wells. Also, observation well 17S/50-7db2 (fig. 7) provided data during tests of production wells 1, 2, 3, and 4. Figure 21 presents a graphical method for testing the consistency of the aquifer-test data in table 4 and for recognizing degrees of hydraulic connection or isolation. Transmissivities determined from pumped wells are plotted on the right side of the graph; no estimates of storage coefficients were made from pumped-well data. The remaining data points represent transmissivities and storage coefficients resulting from observations in nonpumping wells (lower numbers) during pumping of wells 1 through 5 (upper numbers). Where pairs of wells were observed, first with one pumping and then with the other pumping, the data points are connected. No implication of a relationship between transmissivity and storage coefficient is intended in this illustration. As an example of the use of figure 21, consider the data gained from wells 1, 2, and 3. The transmissivity calculated from well 3 data during pumping of well 1 was about the same as that determined from measurements in the pumped well. Apparently this means that the major transmissivity in well 1 is in the same aquifer as that in well 3. When well 3 was pumped, however, a significant part of discharge came fig/d mZ/d [05 ‘IO4 I/7db2 . ISA-{dim .5/l3 I04 4/5 4/2. .4/3 .4/I ' .4/7de 5/4 l/2 emu/.0 \ \gl/3 2/../ EXPLANATION 3/l denotes date from observations in well | during pumping of well 3 IO3 —- Lines connect data from pairs of wells allernolely pumped and observed TRANSMISSIVITY, IN FEET SQUARED PER DAY AND METRES SQUARED PER DAY (STORAGE COEFFICIENTS NOT DETERMINED) @4 10‘4 10‘3 500 TRANSMISSIVITIES DETERMINED FROM PUMPED WELLS Io'2 Io" STORAGE COEFFICIENT FIGURE 21.—Transmissivities plotted against storage coefficients calculated from aquifer tests in southern Ash Meadows. MOVEMENT 0F GROUND WATER IN ASH MEADOWS AREA 47 frOm a zone not penetrated by well 1, and the draw- down in well 1 was less than it would have been if the entire discharge came from the aquifer that wells 1 and 3 mutually draw upon. This resulted in a falsely high calculated transmissivity. The value determined from well 3 alone when it was pumped may be closer to the true value. The range of transmissivities in this interplay is from 5,900 ftZ/d (550 mzyd) to 18,000 ft2/d (1,700 m2/d), or within a factor of about 3. The storage coefficients are reasonable if some dewatering is considered. Consequently, the degree of hydraulic connection, considered in the context of this complex aquifer system, is classed “good.” Similar analyses of other data in figure 21, combined with the observed long-term effects of pumping in 1971 and 1972 as described earlier in this paper, lead to a general and largely intuitive classification of the degree of hydraulic communication among various wells and Devils Hole (fig. 22). The degree of isolation of well 2 within a triangular array of wells having good connections is consistent with its unique tie to Jack Rabbit Spring. The implications as to the usefulness of mathematical models of this complex system are obvious. Through a long process of trail and error and the introduction of many poorly justified assumptions, it would be possible to reproduce effects that have been observed. Predicting the effects of changing the magnitude or, more importantly, the points of applications of pumping stresses must usually meet with failure. GEOLOGICAL EVIDENCE ROLE OF TRAVERTINE BEDS It has been stated or implied at several places earlier in this report that travertine beds, and some of the more massive continental limestones for the purposes of this discussion, are the dominant local aquifers. There are three lines of evidence supporting this belief. First, among the productive wells and test holes, only three (well 5, well 10, and observation well 17S/50-36dd) have production from gravel, according to the drillers’ logs (table 3). The aquifers in well 5 were not identified, but the log shows more “limestone” than gravel. Moreover, frequent dismantling of the discharge meter on well 5 during 1971 showed the mechanism to be immobilized by flakes of a calcareous, light brown, crystalline mineral about the size of coarse sand and believed to be travertine. All other productive wells and test holes in Ash Meadows have a dominant lithology variously described as “limestone,” “lime," “caliche,” and “travertine.” R.50E, R.5lE. Sec. 36 3| DEVILS HOLE T I78 0 $§7§u “0 I2 NT.I8$. HYDRAULIC CONNECTION Good ———-— Fair —-—-— Moderate Poor 0 v2 MILE t————,—4 o .5 KILOMETRE FIGURE 22.—Generalized degrees of hydraulic connection among Devils Hole, production wells, and observation wells in southern Ash Meadows. Secondly, drilling records show that dropping of the drilling tools in these beds is not uncommon, attesting to the conduit permeability of the travertines. Among the wells in which the tools dropped were well 2 and well 6, both of which when pumped produce immediate effects on springs. Most convincing, however, is examination of the lithology occurring at the major springs, loci of almost all of the natural discharge. Without exception among the springs discharging 400 gal/min (2,200m3/d) or greater, these carbonate beds crop out in or on the sides of the spring pools. At many of the springs (King Pool, Crystal Pool, and Fairbanks Spring are the clearest examples) the water can be seen to issue from the travertine. STRUCTURAL CONTROL An additional feature of the travertine beds is that they rarely occur west of the springs except in southernmost Ash Meadows. At several of the major springs they are terminated abruptly at the eastern walls of the conical spring pools. Big Spring, Crystal Pool, and Rogers Spring demonstrate this particularly well. Fairbanks Spring is an exception in that the travertine is terminated at the north side of the spring 48 EFFECT OF PUMPING ON PUPFISH HABITATS IN ASH MEADOWS, NYE COUNTY, NEVADA pool. These observations leave little room for doubt that the springs are fault controlled. Gravity data presented by Healey and Miller ( 1971) show that the valley-fill deposits are thickest in two localities. The first is centered about 1 mi (1.6 km) southeast of Big Spring. Big Spring lies within the gravity low, while the northern limit is approximately at Jack Rabbit Spring. Crystal Pool is at the southeastern limit of the second gravity low, which extends in an elliptical pattern to the northwest, its northeastern side corresponding with the spring line. With the observed truncation of the travertine at Crystal Pool and the linearity of the 2,200-ft (670-m) contour to the northwest, the gravity data indicate that a persistent, high-angle fault controls the spring line. It may be tectonic, bounding down-faulted blocks beneath Ash Meadows. Greater compaction of the thick lake beds in the gravity lows could also provide the strain necessary for non-tectonic compaction faults. The topography of Ash Meadows and the hills to the east display numerous lineations that suggest an extensive network of faults, some of them displacing the youngest deposits. Figure 23 shows this pattern, perhaps carried to the extreme but useful in explaining certain peculiarities of the hydrologic system. The fault defining the Devils Hole cavern, which strikes N. 40° E., can be extended with little stretch of the imagination to explain the offset of the segmented hills east of Devils Hole. The southwestward extension is less certain, for the offset of the 2,200-ft (670-m) contour between Davis Springs and Crystal Pool is of the opposite sense of movement (right-lateral rather than left-lateral). A fault that is subparallel to this might explain the southward twist of the topography on the east side of Point of Rocks and the apparent isolation of King Pool from the wells in unit A. A fault having the same general orientation southeast of Longstreet Spring provides explanation for the apparent (on the basis of temperature) hydraulic isolation of pumping unit E from areas to the . south. The sharp contrast between water in the “Five Springs” area, including well 7, and water from Longstreet Spring supports the hypothesis of a major fault. The gravity data presented by Healey and Miller (1971) show that the topographic high represented by the hills extends northwestward in the shallow subsurface. The northwest-trending fault shown west of Cold Spring, in the northwest corner of the map, is inferred on the basis of a narrow, linear dune that is held by phreatophytes (largely salt cedar), presumably watered by the greater permeability of the fault. PATHS OF SPRING DISCHARGE Two widely separated points along the discharge path of Jack Rabbit Spring are known. These are the spring itself and travertine beds penetrated by well 2, probably those at a depth of about 60 ft (18 m). Jack Rabbit Spring, then, discharges through a shallow, linear conduit system in travertine that is terminated at the spring by a fault. The setting of Crystal Pool is almost as clear, although well 6 is much closer to the spring. It is possible that the travertine beds at Crystal Pool were draped over the land surface by an ancestral spring issuing from Devils Hole, thus providing a permeable path for discharge when the water level declined. On the basis of their temperatures and chemistry, Big Spring, Bole Spring, and Fairbanks Spring are thought to discharge through long paths in local aquifers, probably at relatively shallow depth. Rogers and Longstreet Springs, because of their proximity to the gravity high, may discharge along faults vertically from the carbonate rocks, as proposed most recently by Winograd (1971). The chemical and temperature data neither confirm nor dispute this interpretation. SYNTHESIS OF FLOW NEAR DEVILS HOLE The water-table map (fig. 10) presented earlier implies that the deep southwestward flow in the lower carbonate aquifer is forced upward along faults that segment the hills east of Ash Meadows. This produces a mound of unconfined water which discharges laterally into the shallower local aquifers. Water confined in the deep local aquifers is given a high potentiometric head by communication with the faults defining the southwestern boundary of the hills. The most active flow paths of the local subsystem are those in the shallow aquifers feeding the springs of southern Ash Meadows. Figure 24A shows conceptually the horizontal component of this rising, confined flow in the regional aquifer and its subsequent discharge to warm springs close to the hills or alternate discharge to local aquifers supplying the outlying springs. Under the stresses of pumping (fig. 243) the system changes little in pattern. Pumping of wells 4 and 5 produces a significant change along the range front between Devils Hole and Point of Rocks. The reality of. this flow path, which may in fact be along the boundary faults close to the hills, is borne out by the distinct response of observation well 17S/50-36dd (900 ft or 275 m east of Devils Hole) to pumping of wells 4 MOVEMENT OF GROUND WATER IN ASH MEADOWS AREA He°20' “6° :5“ EXPLANATlON ——LINEATION 0R POSSIBLE ”grins L: Collxns ”\ [T/ ..\..,\;c.._. W P M ol:g\\ \\ :Hc\lcher Springs \\ Spr] ‘* " ~ 3 \9 lack Rcbbltfi FAULT— Dashed where approximalely located 0 IMILE == 0 I ZKILOMETRES 5g Contour Interval ZOOfeeHSl metres) (supplementary contours‘.40fee1 orlZ [nelresl 36° 30' Base from U 8 Geological Survey, Ash Meadows, l'62.500 FIGURE 23.—Lineations and possible faults in Ash Meadows and vicinity. 36° 25‘ 49 50 EFFECT OF PUMPING ON PUPFISH HABITATS IN ASH MEADOWS, NYE COUNTY, NEVADA N lMILE O | KILOMETRE XW ’// / I . 7//// i/ . Pyool III/ I l \2‘ \ \\\\\\ i / I/ 4 / WW" ' / Poorig/ / i Davis"0 ‘1’, If P / i Springs 40 Po 4— “ i Sink Spring i fdock Rabbit \ Spring N 0 l MILE I——.——I O | KlLOMETRE \\\\\“ Vg \‘ \ k \\\\\\ s 1% Vi I //// / / 7%? /://// ’////// li/ // ’89 /// I //¢ 06/ DEVILS HOLE ’/ \ ’ i Crystal Pool Davis ~° Springs "p pdock Rabbit /’ Spring A. Natural flow system 5. Flow system modified by pumping wells l-6 and l7. FIGURE 24.——Conceptual models of dominant and diffused flow in the vicinity of Devils Hole. and 5. The small arrows on figure 24 represent diffused flow through fractures and joints that are not enlarged significantly by solution. The greatly increased diversion to pumping unit A, however, captures water that otherwise would rise near Devils Hole and thus allows a relaxation or lowering of the pool in Devils Hole. Whether this flow path remains in the lower carbonate aquifer beneath the valley north of the well field, or rises in the northern part of the valley to flow south through local aquifers, is unimportant. The response of observation well 17S/51-31dd to pumping in unit A and the diffused but significant effect on Devils Hole adequately confirm this general flow path. Diffused flow through minor faults and joints supplies some of the smaller springs, but it is evident that two or three master conduits expel most of the water to discharge points in southern Ash Meadows. DEVELOPMENT WITH MINIMUM IMPACT The discussion above makes it clear that pumping from units A and B has a very high probability of affecting Devils Hole significantly. New wells in unit C, unless compensated by further reducing the flow of Crystal Pool, also carry a high risk. It is difficult to evaluate the impact on Devils Hole of developing additional supplies from unit D. Moreover, no productive aquifers other than the lower carbonate aquifer have been found in unit D, and the lack of major springs suggests that none occur at relatively shallow depth. Development west of the spring line would have less effect on Devils Hole, but the low productivity of the sediments and poor quality of the water preclude western Ash Meadows as a significant and useable source of irrigation water. This process of elimination leaves only pumping unit E, the northern part of the ranch property and of the Ash Meadows discharge area. The temperature of the significant discharge from Longstreet, Rogers, and Fairbanks Springs suggests a long and shallow approach path from the northeast and east. Whether one, two or three master conduits in the lower CONCLUSIONS 51 carbonate aquifer feed these. springs is not important. There is no evidence presently (August 1974) available which would indicate that such conduits are in close communication with those in the deeper aquifer supplying areas to the south. Exploratory drilling in unit E has been quite extensive and almost completely without success. Moreover, if the master conduit(s) is eventually discovered and found to be very shallow, sufficient drawdown may not be available to increase significantly the gradient toward the discharge area. Compensation of well discharge by decreased spring flow would be the result. If a few tens of feet of drawdown could be induced without dewatering the conduit or conduits, the total discharge of unit E might be increased greatly. Because the better farmland is in the south, export of most of this water would be necessary. Note, however, that overdraft pumping is inherent in this, and the ground-water basin, again thrown into nonequilibrium, would attempt to readjust. Whether the new balance would be achieved by northwestward growth of the Ash Meadows ground—water system to capture a part of the Pahute Mesa system, or whether it would be achieved by reducing flow to and water levels in the southern part of the Ash Meadows discharge area, cannot be predicted. If the former occurs, water rights within the Pahute Mesa system may be injured, thus initiating another water—rights dispute. In a classic paper describing types of carbonate aquifers, the frustrations of investigating them were stated by W. B. White (1969, p 15): “Carbonate aquifers have long posed a headache for hydrologists because of the localized characters of the ground-water flow and the lack of response to standard techniques for aquifer evaluation." The evidence presented in this study indicates that the aquifers in the local subsystem at Ash Meadows are no less capricious than the paths of flow in the carbonate aquifer that supplies them. CONCLUSIONS The Ash Meadows discharge area is geologically and hydraulically very complex in detail. It can, however, be divided into two gross units by a line defining the western limit of significant spring, discharge which, over much of its path, coincides with a persistent high- angle fault cutting the youngest strata beneath the valley floor. There is no evidence at the present time that withdrawals of ground water to the west of the spring line would produce drawdown in the Paleozoic carbonate rocks nor diminish the flow of major springs. However, production from this area does not appear feasible because of the low productivity of the aquifers and poor quality of the water. The quality and quantity of water produced east of the spring line are generally suitable for irrigation. Used together with pumping-test and temperature data within the framework of observed and inferred geologic features, chemical data confirm that the regional lower carbonate aquifer is the source of the discharge at Ash Meadows and allows delineation of flow paths in the local discharge area. Most if not all of the larger springs remote from outcrops of the regional aquifer are supplied by shallow and linear travertine aquifers. Pumping from the shallow aquifers in eastern Ash Meadows south of Crystal Pool (units A and B on fig. 17) caused the 2.5-ft (0.75-m) decline observed between 1968 and 1972 in the pool level in Devils Hole. All wells in secs. 7 and 8, T. 18 S., R. 51 E., draw water from the lower carbonate aquifer by lowering the water table and potentiometric surface in the local aquifers, thus inducing more flow from the east. Of all the wells in units A and B, only well 2, which totally captured the flow of Jack Rabbit Spring, was significantly compensated by reduced spring flow. Liberal estimates of additional salvage of water from springs, by infiltration of irrigation water, and by clearing of phreatophytes, still resulted in an estimated overdraft in 1971 from units A and B of more than 1,500 acreft (1.85 million m3), or an increase of almost 10 percent in the total discharge from the Ash Meadows ground-water basin. Well 6 in pumping unit C captured most of its discharge from nearby Crystal Pool and had little effect on water levels elsewhere. In unit D well 7, the only well producing directly from the lower carbonate aquifer, also was largely compensated by reduced spring flow. Additional wells in units C and D would have a greater probability of affecting Devils Hole. Fairbanks, Rogers, and Longstreet Springs responded little or not at all to pumping of well 8 in unit E, although the well captured the total flow of Soda Spring. Spring discharge in unit E has declined on a sustained basis in comparison to pre-1963 records. Pumping from the Amargosa Farms area to the northwest may have been responsible for these declines. The only area for developing additional water in Ash Meadows with possibly only a slight impact on Devils Hole is in pumping unit E. Adjustment of the regional flow system to new pumping stresses in this area may occur as expansion of the boundary of the Ash Meadows ground-watersystem into the adjacent Pahute Mesa system. 52 EFFECT OF PUMPING 0N PUPFISH HABITATS IN ASH MEADOWS, NYE COUNTY, NEVADA REFERENCES Bateman, R. L., Mindling, A. L., Naff, R. L., and Joung, H. 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R., 1965, The response of well-aquifer systems to seismic waves: Jour. Geophys. Research, v. 70, no. 16, p. 3915-3926. Denny, C. S., and Drewes, Harald, 1965. Geology of the Ash Meadows Quadrangle, Nevada-California: U.S. Geol. Survey Bull. 1181-L, p. L1-L56. Healey, D. L., and Miller, C. H., 1971, Gravity survey of the Amargosa Desert area of Nevada and California: U.S. Geol. Survey rept. USGS-474-136, 29 p.; available only from U.S. Dept. Commerce, Natl. Tech. Inf. Service, Springfield, Va. 22151. Hughes, J. L., 1966, Some aspects of the hydrogeology of the Spring Mountains and Pahrump Valley, Nevada, and environs, as determined by spring evaluation: Masters thesis, Univ. of Nevada, Reno. Hunt, C. B., and Robinson, T. W., 1960, Possible interbasin circu- lation of ground water in the southern part of the Great Basin: U.S. Geol. Survey Prof. Paper 400-B, p. 8273-3274. Johnston, R. H., 1968, U.S. Geological Survey tracer study Amargosa Desert, Nye County, Nevada. Part I: Exploratory drilling, tracer well construction and testing, and preliminary findings: U.S. Geol. Survey open—file rept., 64 p. Larson, J. D., 1973, Water-resources data collected in the Devils Hole area, Nevada, 1972 — 73: U.S. Geol. Survey Water-Resources Inv. 61 - 73, 30 p. [1974[. 1974, Water-resources data collected in the Devils Hole area, Nevada, 1973—74: U.S. Geol. Survey Open-File Rept. 74 — 330, 19 p. Loeltz, 0. J ., 1960, Source of water issuing from springs in Ash Meadows valley, Nye County, Nevada [abs.]: Geol. Soc. America Bull., v. 71, no. 12, Part 2, p. 1917-1918. Lohman, S. W., 1972, Ground-water hydraulics: U.S. Geol. Survey Prof. Paper 708, 70 p. Lohman, S. W., and others, 1972, Definitions of selected ground-water terms—revisions and conceptual refinements: U.S. Geol. Survey Water-Supply Paper 1988, 21 p. Maxey, G. B., 1968, Hydrogeology of desert basins: Ground Water, v. 6, no. 5, p. 10-22. Meinzer, O. E., 1920, Quantitative methods of estimating ground- water supplies: Geol. Soc. America Bull., v. 31, p. 329-338. Rush, F. E., 1970, Regional ground-water systems in the Nevada Test Site area, Nye, Lincoln, and Clark Counties, Nevada: Nevada Dept. Conserv. and Nat. Resources, Water Resources Reconn. Ser. Rept. 54, 25 p. Scofield, C. S., 1936, The salinity of irrigation water: Smithsonian Inst. Ann. Rept., 1935, p. 275-287. Theis, C. V., 1940, The source of water derived from wells: Civil Eng., v. 10, no. 5, p. 277-280. Walker, G. E., and Eakin, T. E., 1963, Geology and ground water at Amargosa Desert, Nevada-California: Nevada Dept. Conserv. and Nat. Resources, Water Resources Reconn. Ser. Rept. 14, 45 p. White, W. B., 1969, Conceptual models for carbonate aquifers: Ground Water, v. 7, no. 3, p. 15-21. I Winograd, I. J ., 1962, Interbasin movement of ground water at the Nevada Test Site: U.S. Geol. Survey Prof. Paper 450-C, p. C108-Clll. 1963, A summary of the ground water hydrology of the area between the Las Vegas Valley and the Amargosa Desert, Nevada, with special reference to the effects of possible new withdrawals of ground water: U.S. Geol. Survey openfile rept. TEI—840, 79 p. 1971, Origin of major springs in the Amargosa Desert of Nevada and Death Valley, California: Ph.D. dissertation, Univ. of Arizona, Tucson. Winograd, I. J ., and Thordarson, William, 1975, Hydrogeologic and hydrochemical framework, south-central Great Basin, Nevada-California, with special reference to the Nevada Test Site: U.S. Geol. Survey Prof. Paper 712-0, 126 p. [U.S.] Public Health Service, 1962, Drinking water standards: U.S. Dept. Health, Education and Welfare, Public Health Service Pub. 956, 61 p. [U.S.] Salinity Laboratory Staff, 1954, Diagnosis and improvement of saline and alkali soils: U.S. Dept. Agriculture handbook 60, 160 p. Worts, G. F., 1963, Effect of ground-water development on the pool level in Devils Hole, Death Valley National Monument, Nye County, Nevada: U.S. Geol. Survey open-file rept., 27 p. fiUS. GOVERNMENT PRINTING OFFICE: l976—677—3‘0/80 We Po, \ 7 12/62 72$ DAY Distribution, Regional Variation, and Geochemical Coherence of Selected Elements in the Sediments of the Central Gulf of Mexico GEOLOGICAL SURVEY PROFESSIONAL PAPER 928 Distribution, Regional Variation, and Geochemical Coherence of Selected Elements in the Sediments of the Central Gulf of Mexico By CHARLES W. HOLMES GEOLOGICAL SURVEY PROFESSIONAL PAPER 928 An evaluation of semiquantitative data used in the determination of trace-element distribution and abundances in marine sediments UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1976 UNITED STATES DEPARTMENT OF THE INTERIOR THOMAS S. KLEPPE, Secretary GEOLOGICAL SURVEY V. E. McKelvey, Director Library of Congress Cataloging in Publication Data Holmes, Charles Ward, 1937- Distribution, regional variation, and geochemical coherence of selected elements in the sediments of the central Gulf of Mexico. (Geological Survey professional paper ; 928) Bibliography: p. 1. Marine sediments—Mexico, Gulf of—Analysis. 2. Geochemistry, Mexico, Gulf of. I. Title. II. Series: United States. Geological Survey. Professional paper; 928. GC383.5.H65 55225 75—26564 For sale by the Superintendent of Documents, US. Government Printing Office Washington, D.C. 20402 Stock Number 024—001-02766-6 PLATE' 1. FIGURE 1. 0°.“ 9—10. 11. 12. 13—16. CONTENTS Page Metric-English equivalents _________________________________________________ IV Abstract _________________________________________________________________ 1 Introduction _____________________________________________________________ 1 Acknowledgments _____________________________________________________ 1 Geologic setting ___________________________________________________________ 2 Sampling procedure ______________________________________________________ 3 Analytical procedure ______________________________________________________ 3 Data reduction ___________________________________________________________ 5 Results and discussion ____________________________________________________ 6 Geochemical abundance and distribution of elements ______________________ 6 Regional variations and geochemical coherence ___________________________ 9 Iron-vanadium group _____________________________________________ 12 Manganese subclass ___________________________________________ 13 Calcium-strontium group ___________________________________________ 17 Conclusion _______________________________________________________________ 21 References cited __________________________________________________________ 22 ILLUSTRATIONS Page Circular histograms of elemental concentrations versus frequency percent ........................ In pocket Map showing physiographic provinces of the Gulf of Mexico basin (Garrison and Martin, 1973) _______ 2 Map showing generalized surficial sediment distribution of the Gulf of Mexico basin ................. 3 Map showing location of sampling stations ________________________________________________________ 4 Histogram showing the number of cores of various lengths _______________________________________ 6 Histograms showing frequency distribution of 21 elements for all samples taken in the central gulf basin 9 Histograms showing frequency distribution of 20 elements for samples of Pleistocene age in the central gulf basin _________________________________________________________________________________ 9 Schematic of element associations based on the calculated correlation coefficients and factor analysis ___- 11 Circular histogram of frequency versus clay percentage in cores from the central gulf basin ___________ 13 Variation diagrams showing the distribution of iron, manganese, and manganese to iron ratio with depth in cores from a: 9. Southeast-northwest transect in the eastern gulf basin _____________________________________ 14 10. North-south transect in the western gulf basin _____________________________________________ 16 Variation diagram showing vertical distribution of spectrographically determined manganese from the top 3 m of 46 cores ____________________________________________________________________________ 18 Graph showing comparison of manganese determined by atomic absorption analysis of leached material and by spectrographic analysis of whole samples ________________________________________________ 19 Variation diagram showing: 13. Manganese, emv, and pH in the upper section of core 28 _________________________________ 19 14. Detailed analyses for manganese, iron, and calcium from the upper metre of four cores from the major provinces of the Gulf of Mexico ______________________________________________ 20 15. Distribution of manganese, iron, and calcium between 500- and 630-m depth in core 28 _______ 21 16. Calcium, strontium, and calcium to strontium ratio in cores from north-south transect in the western gulf basin _________________________________________________________________ 22 III IV CONTENTS TABLES Page TABLE 1. Core locations ______________________________________________ 5 2. Analytical ranges of detection _______________________________ 6 3. Elements detected in less than 50 percent of the samples or not detected at all ___________________________________________ 6 4. Geometric mean compositions and geometric deviations of samples of sediment cores in the central Gulf of Mexico ____________ 7 5. Average element content in central Gulf of Mexico sediments ____ 8 6'. Correlation coefficients among 20 elements based on all sediment samples taken during the cruise of the U.S.N.S. Kane in 1969 10 7. Correlation coefficients for the Pleistocene samples ______________ 10 8 Average manganese content of the total sediment and of the sedi— ment on a carbonate-free basis (CFB) for those cores for which the Holocene-Pleistocene boundary has been defined____ 19 9. Carbonate uranium-thorium disequilibrium ____________________ 21 METRIC-ENGLISH EQUIVALENTS Metric unit English equivalent Metric unit English equivalent Length Specific combinations—Continued millimetre (mm) = 0.03937 inch (in) litre per second (1/5) = .0353 cubic foot per second metre (m) = 3.28 feet (ft) cubic metre per second kilometre (km) = .62 mile (mi) per square kilometre [(ms/s)/km1] = 91.4? cubic feet per second per Area square mile [(ftS/s)/mi9] metre per day (m/d) = 3.28 feet per day (hydraulic square metre (m5) = 10.76 square feet (ft?) conductivity) (ft/d) square kilometre (kmfl) = .386 square mile (mi?) metre per kilometre _ hectare (ha) = 2,47 acres m m = 0.28 feet per mile (ft/mi) kilofinetie) per hour 9113 f t d (ft/ ) m = . 00 per secon s Volume metre per secdond (fin/s) = 3.28 feet per second .1 _. a me re s uare per ay ffi'r’éc (“lint‘metre (cm ) ; 633831 333}: £33395“ ) (mi/d1) = 10.764 feet squared per day (its/d) cugic metre (m3) = 35.83081 cubicf fe€t((£t3)f ) cubic metre per second (transmlsliflty) cu c me re = . acre- 00 acre- t cubic hectometre (hmfi) 2810.7 acre-feet (ma/B) = 22.826 million gallons per day litre = 2.113 pints (pt) (MSR /d> litre = 1‘03 quarts (qt) cubic metre per minute litre = 23 gallon (gal) (ma/min) =264.2 gallons per minute (gal/min) cubic metre = .00026 million gallons (Mgal or litre per second (Us) 2 15.85 gallons per minute 10a gal litre per second per cubic metre = 6.290 barrels (bbl) (1 bbl=42 gal) metre [(i/s)/ml = 4.83, gallons per minute per foot kil t h [(gal/minvft] ' ome re per our Weight (tkm/h) d ( / ) = 212337 mile per h%ur (mi/h) gram (g) = 0.035 ounce. avolrdupois (oz uvdp) me re per “co“ m s = ' ‘ m es per our _ .- . gram per cubic 55:3; (t) Z 130022 i’glilslldshli‘lgllguggosllglb map) centmfletre (g/cm“) 2 62-43 pounds per cubic foot (lb/ft“) t = .98 ' gram per square onne 8 ton, long (224011)) centimetre (g/r-lni’) : 2.04.? pounds per square foot (lb/ft?) - - - gram per square Spec1fic combinations centimetre .0142 pound per square inch (lb/in“) kilogram per square centimetre (kg/cm?) = 0.96 atmosphere (atm) Temperature kilogram per square . centimetre 2 degree Celsius (°C) 2 1.3 degrees Fahrenheit (”F) cubic metre per second (ma/S) Ii .98 bar (0.9869 atm) 35.3 cubic feet per second (ftn/s) degrees Celsius (telliperature) : [ (1.8 X °C) +32] degrees Fahrenheit DISTRIBUTION, REGIONAL VARIATION, AND GEOCHEMICAL COHERENCE OF SELECTED ELEMENTS IN THE SEDIMENTS OF THE CENTRAL GULF OF MEXICO By CHARLES W. HOLMES ABSTRACT A semiquantitative six-step spectrographic method was used to analyze 2,482 sediment samples from 50 piston cores, averaging 6 m in length, from the Gulf of Mexico. 0f the 30 elements scanned for, 20 (B, Ba, Be, Ca, Co, Cr, Cu, Fe, La, Mg, Mn, Nb, Ni, Pb, Sc, Sr, Ti, V, Y, Zr) occurred in a suflicient number of samples for valid statistical analysis. Paleontological studies of some cores provided a basis for determining differences between the distributions of elements in Holocene and Pleistocene sediments. The abundances of these elements as estimated for all 2,482 samples and for each age group, show significant differences for only 6 of the 20 elements. Boron, titanium, vanadium, and zirconium are more abundant in sediments of Pleistocene age, whereas cal— cium and strontium are more common in the Holocene sedi- ments. These distributional differences reflect the mechanical erosion and rapid deposition of the glacial epochs of the Pleistocene and the dominant pelagic deposition of the Holo- cene. A statistical measure of the geochemical coherence of the elements suggests that they fall into three geochemical groups or associations. One group, containing iron and vanadium, was associated with clay-size particles; 3. second group, con- taining calcium and strontium, was associated with the car- bonate component of the sediments. The third group, con- taining beryllium, niobium, and lead, was seemingly unre— lated to anything, possibly because its distribution is severe- ly censored by the analytical method The analytical method used in this investigation permitted rapid analysis of large numbers of samples Although the analytical resolution fails to provide definition of the chemi« cal species, the data nevertheless provide sufficient informa- tion to aid in solving major geochemical problems. IN TRODUCTION In 1968 the US. Geological Survey began a recon- naissance study of the trace—element composition of the surface and nearsurface sediments in the Gulf of Mexico. The purpose of the study is to begin to build the background. of geochemical data that will provide a better knowledge of (1) the sedimentary processes by which trace elements are both dis- persed and concentrated in the marine environment; / (2) the mechanics and rapidity of diagenesis after deposition and burial; (3) the general crustal abun- dance of the elements in the recent sediments of the World’s oceans, more specifically for the Gulf 01f Mexico; and (4) the influence of salt tectonics on geochemical cycles Within the sediments. Such knowledge is essential‘for determining the magni- tude and extent of impact of the increasingly large volumes of waste being introduced into coastal wa- ters and for determining baselines against which in- creasing levels of anthropogenic pollution in sedi— ments can be measured. The elemental composition of the surface sedi- ments of the continental shelf has been described in an earlier report (Holmes, 1973) ; the present re- port is based on the semiquantitative spectrographic analysis of 2,482 samples selected from 50 cores from the Gulf of Mexico. The cores were obtained during a study sponsored jointly by the US. Geo- logical Survey and the US. Naval Oceanographic Office. The analytical data were evaluated to deter- mine the extent that its semiquantitative nature lim- its its usefulness in solving geochemical problems. This was accomplished by treating the data as quan- titative, and then by comparing the results of the analyses with published chemical studies. ACKNOWLEDGMENTS I wish to acknowledge the aid of the officers and crew of the USNS Kane and the chief scientist, Wil- liam T. McComas, and the staff of the US. Naval Oceanographic Office. The assistance and advice of Paul Carlson, Arnold Bouma, E. William Behrens, and Patrick Parker during the field phase of the program are gratefully acknowledged. The coopera- tion and assistance of the staff of the field services section of the U. S. Geological Survey, part1cularly Jerry Motooka, Carl Forn, Arthur Toeves, David 1 2 SEDIMENTS OF CENTRAL GULF OF MEXICO Siems and Gordon Day, who made the spectro- graphic analyses, are recognized. A special thanks is extended to A. P. Marranzino and D. J. Grimes who arranged to place a spectrograph aboard the ship, and also to Lamont Wilch and Glenn Allcott for aid in the computer analyses. The laboratory analyses were done by J. J. Dillon, C. Duerr, and Mike Dorsey. GEOLOGIC SETTING The Gulf of Mexico basin is almost completely sur- rounded by a land mass of diverse geologic history. It covers approximately 1.6 million km2 and has a maximum water depth of more than 3,600 m. (See fig. 1.) The continental interior of the United States via the Mississippi river is the major source of elastic material found in the gulf basin. This sediment cov- ers the entire eastern portion of the basin and ‘ V? / .1 Cmvon . raw/g . Mininippi ‘ ‘ Tronghf ‘wssr W spreads westward onto the abyssal plain. Sediment from other river systems that border the northern gulf is deposited on the broad shelves of this region. The rivers entering the gulf along the southwestern margin of the basin contribute little sediment to the gulf basin due to their relatively small drainage basins. Significant elastic deposits are absent on exposed lands adjoining the Florida shelf and Cam- peche shelf; the extreme width of these shelves inhibit any contribution of noncarbonate elastic material from the Florida or Yucatan peninsulas. Davies (1968), however, has shown that the Cam- peche shelf may have been an important source of elastic carbonate sediment on the abyssal plain; there is no evidence, though, of any Florida shelf sediment in the basin. Textural analyses show that the predominant sedi- ment in the central basin of the gulf is silty clay having an average clay content of 71 percent. In the eastern gulf, a veneer of light-brown to reddish- 84' Dosmo .UyT" ‘ t 2“ _“7o N/ fl .7 S'GSBEE "figsof xx‘x Sign,“ Knolls ,4. A ‘1» xvr‘*yf o, . 4/ . , «w . PRov; E \ g 33%. \h f a "Golfo de/ 4.. "i . Campeche,;r—L \ o ., 1\ r CAMPECHE‘” ‘4 300 KILOMETRES \_ O .— O O 200 MILES Contour Interval <200m water depth —100m >200m water depth—400m «y 1 1» Depression contour FIGURE 1.—Physiographic provinces of the Gulf of Mexico basin (from Garrison and Martin, 1973) . GEOLOGlC SETTING 3 brown sandy clay ranging from 50 to 150 cm in thickness overlies gray silty clays. The sand-sized material is composed principally of foraminiferal tests. Cores in the western gulf exhibit layers of sand-sized carbonate detritus from Campeche Bank, volcanic ash from Mexico, and pelagic foraminiferal tests. Figure 2 is a. map of the sediment distribution in the central gulf. SAMPLING PROCEDURE Core sites were selected to give a representative sampling of the major physiographic provinces of the gulf. These 50 cores, taken by a modified Ewing piston corer (fig. 3 and table 1), ranged in length from 16 to 1,122 cm, averaging 703 cm. Thirty-nine 98' 96' 94' 92' 90- l l l l l _ UNITED STATES 3O 28' l— 26’ 24° ~ 22'— 18' — 500 KILOMETRES J l 300 MILES 16. l l l l | ________,__ YUCATAN PENINSULA y cores scattered throughout the basin were at least 6 m in length (fig. 4), giving a representative section of at least6 m in each physiographic province. After each core was taken, it was immediately split, described, photographed, and sampled. For the geochemical analyses, 1-g (wet) samples were taken every 20 cm from the center of the split core at the surface and from above and below major changes in lithologic character. This sampling procedure yielded a total of 2,482 samples. ANALYTICAL PROCEDURE Samples taken from the center of the split core were analyzed for 30 elements by the 6-step semi- quantitative method of Grimes and Marranzino 30’ 28' 26' —,—-———— 24' EXPLANATION Shell, algal coral, and oolite Q sand Globigerina—ooze, silt, and clay Silt. clayey silt, silty clay, and clay Sand. silty sand, sandy silt, and sand-silt-clay Algal coral capping, reef, ridges. domes, and pinnacles \V Carbonate turbidities (Davies, 1968) Area of slumping (Walker and Massingill, 1970) a 22‘ '/ 18' § 0 Core location Sediment distribution modified from Uchupi and Emery,(l968) I l l ,6. 98' 96' 94' 92' 90‘ 88' 86' 84‘ 82' 30° FIGURE 2.—Generalized surficial sediment distribution and location of core holes in the Gulf of Mexico basin. 4 SEDIMENTS OF CENTRAL GULF OF MEXICO 98‘ 96' 94' 92' l l 1 x 30. _ UNITED STATES 28‘ —- 26. 3-- 24- — .28 1g4 .120 .118 .145 200 22‘ — .143 — 22‘ .127 .1413 429 139 YUCATAN 138. . PENINSULA 20‘ r .131 .136 — 20' {5; 00 18' — CONTOUR INTERVAL 200 METRES — 18° 0 100 400 500 KILOMETRES 2? LL 1 l l l l l I I I | I I I r 0 1(1) 200 300 MILES 15- 1 1 z I 1 1 1 l I ,6. 98' 96' 94' 92' 90' 88‘ 86' 84' 82' 80' FIGURE 3.—Location of sampling stations. (See table 1.) (1968). The results are given as the geometric mid- point (such as 0.1, 0.15, 0.2, 0.3, 0.5, 0.7, and 1.0 percent or parts per million) of the geometric brackets having the boundaries of 0.083, 0.12, 0.18, 0.26, 0.38, 0.56, 0.83, 1.2, and so forth. This precision of a reported value ‘is approximately plus or minus two brackets at the 95 percent confidence level. ~ Of the 30 elements looked for (table 2), 19 were found to be Within the limits of detection (table 4) in over 50 percent of the samples. Data on the 11 elements detected in less than 50 percent of the sam- ples or not detected at all are listed in table 3. Atomic absorption methods were used to analyze 150 additional samples for “authigenic” iron, man- ganese, and calcium. These samples were air dried, ground in an agate mortar and pestle, and shaken for approximately 12 hours in a 50-ml solution of 1 ‘ M hydroxylamine—hydrochloric and 25 percent (v/v) acetic acid. This procedure dissolves the nonsilicate ferromanganese minerals and the carbonate miner- als, and it extracts adsorbed trace elements but does not affect detrital-silicate or authigenic-sulfide min- erals (Chester and Hughes, 1967). Replicate analy—‘ wes of selected samples established the analytical precision of this method to be below 10 percent. Uranium and thorium content and isotopic com- position of selected carbonate samples were deter- mined by' alpha spectroscopy after chemical separa- tion (Holmes, 1965). The pH was estimated with a flat-bulb combination electrode, standardized with ANALYTICAL PROCEDURE 5. ~ TABLE 1.—Corc locations C132? Latitude Longitude d em???) ) Geographic area lengglgrfcm) 26°17.1’ 87°00.1’ 3,035 Toe Mississippi Fan 780 24°32.8’ 85°40.5’ 3,346 -___do __________________ 988 24°08.0’ 85°16.1’ 3,340 _--_ o __________________ 925 23°40.0’ 84°40.0’ 3,320 Sill-Florida Straits 940 25°29.0' 84°55.5’ 3,320 Florida Scarp 960 25°05.0’ 86°02.1’ 3,162 Mississippi Fan 859 24°17.1’ 88°28.5’ 3,541 Canyon in Campeche Scarp 342 24°50.1’ 88°37.1’ 3,505 Sigsbee Plain 870 26°35.0’ 86°25.0’ 3,233 Mississippi Fan 978 27°13.0’ 85°26.8' 3,114 Florida Rise 841 26°52.2’ 87°24.8' 2,805 Mississippi Fan 380 25°57.0’ 89°03.9’ 3,105 ____do __________________ 200 26°34.8’ 89°18.0' 2,863 ____do __________________ 176 27°55.8’ 87°20.7' 2,763 ____do __________________ 840 28°30.6’ 87°39.2’ 2,365 De Soto Canyon 752 28°15.0’ 88°22.0' 3,389 Mississippi Fan 920 24°29.7’ 89°30.9’ 3,572 Sigsbee Plain 920 25°11.0' 89°38.0’ 3,573 ___-do __________________ 260 23°32.7’ 91°29.8’ 3,685 ____do __________________ 817 23°27.0’ 93°11.0’ 3,760 ____do __________________ 965 24°14.1’ 94°20.5' 3,750 ____do __________________ 876 24°04.'8’ 93°12.0’ 3,762 ____do __________________ 927 24°14.7' 92°15.0’ 3,749 ___-do __________________ 1,122 24°04.8' 93°12.0’ 3,706 ____do __________________ 933 25°37.0’ 93°12.0’ 3,408 ____do __________________ 835 25°53.0’ 92°23.0’ 2,388 Sigsbee Rise 880 27°34.0' 93°12.0’ 379 Texas Continental Slope 600 27°13.6’ 96°14.0’ 275 ____do __________________ 16 26°59.7’ 94°18.7' 1,796 Texas-Louisiana Continental Slopes 780 26°19.0’ 93°18.3’ 2,450 Texas Continental Slope 610 25°29.9' 95°23.5’ 1,626 Louisiana Continental Slope 465 ,24°59.9’ 95°00.9’ 3,576 Sigsbee Rise ‘ 447 23°17.8’ 95°15.2’ 3,450 ____do __________________ 775 23°17.8’ 96°10.8' 2,537 Mexico Ridges 920 23°25.0’ 97°36.1’ 46 Mexico Shelf 27 23°15.9’ 96°45.0’ 1,827 Mexico Continental Slope 754 21°50.0’ 96°59.0’ 1,245 Mexico Ridges 710 21°18.0’ 94°23.0’ 3,360 Vera Cruz Tongue 757 20°56.7’, 95°05.7’ 3,108 ____do __________________ 666 20°11.2' 95°59.3’ 2,001 Mexico Ridge 788 19°33.5’ 93°17.9’ 580 Campeche Knolls 822 19°58.9’ 93°15.0’ 1,215 ____do __________________ 767 20°31.5’ 93°13.4’ 1,711 ____do __________________ 820 20°30.0’ 92°37.0’ 2.462 Campeche Canyon 880 21°23.7’ 93°27.9’ 3,169 Campeche Knolls 917 21°54.0' 93°20.8’ 3,393 -___do __________________ 884 22°40.3’ 93°13.0’ 3.720 Sigsbee Plain 714 23°22.9’ 94°25.8’ 3.755 ____ 0 __________________ 910 25°42.5’ 95°56.0’ 1.086 Texas Continental Slope 373 26°28.0’ 91°28.0’ 2,127 Sigsbee Scarp 199 commercially available buffers. In like manner, the redox potential was estimated using a combination platinum electrode calibrated with Zobell solution (Garrells, 1960). DATA REDUCTION The large volume of data that was generated re- quired the use of a computer for efficient data reduc- tion. For this report the “Geosum” program, a US. Geological Survey program designed specifical- ly for semiquantitative spectrochemical analysis was used. The printout from this program gives, for each element for all samples, the maximum and minimum abundance values, a histogram plot, a tabulated frequency distribution, and a statistical summary (the geometric mean and geometric devia- tion). These statistics were determined on four data sets: (1) all 2,482 samples, (2) those samples taken below the Holocene veneer, (3) those samples con- taining more than 1,000 ppm manganese, and (4) all samples in each core, core by core (table 4). The geometric mean and geometric deviation are antilogs of the arithmetic mean and standard devia- tion, respectively, of the logarithms of the analytical values. In samples with elemental concentrations less than the lower limit of detection (table 2), the geo- metric mean and deviation were estimated by a cen- sored-distribution method presented by Cohen lslllll FREQU ENCY LENGTH, IN METRES FIGURE 4.—Histogram showing the number of cores of vari- ous lengths. (1959). The geometric mean is a more consistent measure of the central tendency of a frequency dis- tribution than the arithmetic mean and thus is a bet- ter estimate of the typical or most common concen- tration of the element. The arithmetic mean, on the other hand, is a more accurate expression of ele- mental abundance than the geometric mean (Miesch, 1967). The arithmetic' means were computed from the estimated geometric means and deviations by the method described by Miesch (1967), which is based on the technique of Cohen (1959) and Sichel (1952). The frequency distribution of the elements in indi- vidual cores is depicted by a circular histogram (a histogram whose base has been shaped into a circle). This graphical method makes it easier to see shifts in dominant modes from one core to another. Rota— tion of a modal arm to the right in a succession of cores indicates an increase of the mode in the direc- tion one is observing (pl. 1). Only 17 elements of the 19 measured in more than 50 percent of the samples were mapped in this manner; the remain- SEDIMENTS OF CENTRAL GULF OF MEXICO TABLE 2.—Analytical ranges of detection, in parts per million Element Lower limit Upper limit Ag _______________________ 0.5 5,000 As _______________________ 200 10,000 Au _______________________ 10 500 B ________________________ 10 2,000 Ba _______________________ 20 5,000 Be ________________________ 1 1,000 Bi _______________________ 10 1,000 Ca _______________________ 500 200,000 Cd _______________________ 20 500 C0 ________________________ 5 2,000 Cr _______________________ 5 5,000 Cu ________________________ 5 20,000 Fe ________________________ 500 200,000 La _______________________ 20 1,000 Mg _______________________ 200 100,000 Mn _______________________ 10 5,000 Mo _______________________ 5 2,000 Nb _______________________ 10 2,000 Ni _______________________ 5 5,000 Pb ________________________ 10 20,000 Sb _______________________ 100 10,000 Sc ________________________ 5 100 _ Sn _______________________ 10 1,000 Sr ________________________ 100 5,000 Ti ________________________ 20 10,000 V ________________________ 10 10,000 W ________________________ 50 10,000 Y ________________________ 10 200 Zn ________________________ 200 10,000 Zr ________________________ 10 1,000 TABLE 3.—E’lements detected in less than 50 percent of the samples or not detected at all P eeeee tag Illiir‘ivietx sa££les . . Rang Elem nt detgcfti 1392:1213? (ppm) (ppm) was fou d Ag ________________ 0.5 2 05—15 As ________________ 200 .1 ZOO—2,000 Au ________________ 10 0 ________ Bi ________________ 10 0 ________ Cd ________________ 20 0 ________ Mo ________________ 5 6.1 5—150 Nb ________________ 10 27.4 10—70 Sb ________________ 100 0 ________ Sn ________________ 10 1.7 10—30 W _________________ 50 0 ________ Zn ________________ 200 .7 ZOO—5,000 ing 2 showed so little variation that this type of presentation was unwarranted. RESULTS AND DISCUSSION GEOCHEMICAL ABUNDANCE AND DISTRIBUTION OF ELEMENTS Estimating the abundance of constituents in major rock units of the earth is necessary in solving a range of geologic problems from mining to geo- chemical balances. The most reliable statistic in this regard is the arithmetic mean, that value which is RESULTS AND DISCUSSION 04.40.00 00.40.04 404 444 44.4004 00.4 0.44 00.4 4.44 00.4 4.00 00.4044 00.4 4.04 40.4444 004 0.44 04.4 04.4 404 444 04.4 0.40 04.4 004 044 04.0 44.4 00.0 004 00.4 004 04.4 4004 4040.4. 00.4 0.00 00.44.44 04.4 004 04.4 004 00.4 0.04 00.4 0.04 004 4.00 00.40.00 004 0.04 00.4 0.00 40.4 0.04 044 04.4 004 000 00.40.40 00.40044 40.4 04.0 04.4 04.0 00.4 00.4 004 40.4 000 0004:: 40.44.40 44.44.04 00.4 004 44.4 404 40.4 4.04 44.4 4.04 00.4 4.04 44.4 0.44 04.4 0.44 004 0.40 04.44.04 04.4 004 00.4 004 04.4 4.00 00.44004 40.4 04.0 00.4 00.0 04.4 00.4 00440.4 04 004 404 0.40 00.40.04 04.4 4.40 00.4 004 44.4 04.0 04.4 4.44 04.40.40 44.40.04 00.4 4.04 00.4 4.00 044 0.04 44.4 40.4 44.4004 40.40.40 00.40004 44.4 04.0 00.4 00.0 04.4 004 40.4 00.4 04 404 00.4 0.00 444 4.04 404 044 00.4044 04.4 0.44 44.4 0.04 04.40.40 04.40.00 00.44.44 000.4 0.04 00.44.04 04.4 00.4 04.4404 40.40.40 40.4400 00.4 04.0 004 00.4 04.4 004 04.4 40.4 00 004 00.40.00 044 0.04 04.4 0.40 00.4 000 00.4 40.0 40.4 4.44 00.40.00 04.44.44 04.40.44 044 0.04 40.4 0.04 04.4 404 00.4044 44.40.04 004 000 44.4 00.0 00.4 40.0 404 04.4 40.4 40.4 00 004 004 0.00 04.4 0.04 .004 4.00 40.44004 40.4 00.0 00.4 444 004 0.00 44.4 0.04 40.4 0.04 00.4 4.00 40.40.44 04 04 00.4004 40.4 4.04 00.4 000 00.0 04.0 04.4 04.0 44.4 04.4 00.4 004 04 004 004 0.00 04.4 4.04 40.40.00 44.4 0004 00.4 00.4 40.4 0.44 04.40.40 04.4 0.04 404 0.04 04.40.40 40.4 0.04 44.4 40.4 00.4 004 004 0.44 004 000 00.4 40.0 004 00.0 04.4 044 40.4 04.4 04 404 00.4 0.40 04.40.04 00.44.40 44.4 4044 00.4 40.0 04.4 4.44 00.40.00 44.44.04 404 4.44 00.4 044 00.40.04 04.4 004 00.4444 00.4 0.04 00.4000 00.4 00.0 00.4 00.0 04.4004 00.4 00.4 04 004 00.44.44 04.44.44 004 404 00.4000 44.4 0.44 044 4.04 00.4 0.00 44.4 0.04 40.4 4.04 00.4 444 00.4 4.04 44.4 44.4 04.4044 04.4 4.40 00.4044 00.4 44.0 04.4 00.0 44.4 40.4 40.4 00.4 40 004 04.44.04 04.4 4.04 004 444 404 400 44.4 4.04 04.4 0.04 044 0.40 44.40.04 04.40.04 004 444 404 044 44.4 40.4 04.4004 00.40.00 00.4404 44.4 04.0 44.4 40.0 44.4 404 44.4404 00 004 40.40.00 44.40.04 00.4 044 04.4040 04.4 0.04 00.4 4.04 044 0.00 44.4 0.04 044 0.44 004 004 40.4 0.04 44.4 004 44.4004 04.4 0.00 04.4 000 40.4 04.0 00.4 40.0 04.4 40.4 40.4 04.4 40 004 00.44.00 04.4 0.44 00.40.04 00.4 004 404 4.04 04.4 0.04 404 0.00 04.44.44 44.40.04 40.4 0.40 00.40.04 04.4 044 004 000 04 4: 00.4400 40.4 44.0 00.4 40.0 04.4 40.4 00.4 44.4 00 404 40.44.04 04.4 0.44 00.4 0.40 00.4044 40.4 0.04 04.4 4.04 004 0.00 40.4 0.04 00.4 0.04 04.4 0.00 40.40.44 04.4 00.4 00.4 004 004 0.00 004 000 004 44.0 04.4 00.0 004 40.4 404 00.4 00 044 00.44.00 44.44.44 40.40.40 404 400 004 0.44 44.4 4.04 404 0.00 044 0.04 00.40.04 00.44.04 44.40.04 44.4 00.4 00.4044 404 4.00 004 400 004 04.0 00.4 00.0 40.4 04.4 004 00.4 44 444 004 0.00 00.4 4.04 40.4 0.00 04.4 004 004 0.44 44.4 0.04 00.40.00 04.44.44 00.44.44 40.4 0.00 00.40.44 44.4 40.4 04.4044 00.4 0.00 404 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404 44.4 4.04 44.4 0.04 00.4 0.00 004 4.04 40.4 0.04 00.4 4.40 00.4 0.44 04.4 00.4 04.4 004 00.44.40 004 000 00.4 04.0 004 00.0 04 04 04.4 40.4 00 444 044 0.00 00.40.04 404 004 40.4404 44.4 0.04 44.4 0.04 40.40.00 00.4 0.00 40.4 0.04 00.44.40 00.4 0.04 004 004 04.4400 00.4 4.00 00.4400 44.4 04.0 00.4 00.0 04.4 40.4 00.4 00.4 00 004 004 404 04.4 4.04 40.4 404 0.0.4 404 00.4 044 04.4 4.04 044 4.40 44.40.44 04.4 0.04 00.4 4.00 00.4 0.04 44.4 00.4 444 404 40.40.00 40.4 000 00.4 04.0 004 40.0 044 04.4 00.4 00.4 04 404 004 0.00 00.40.04 404 004 00.4 004 00.4 0.44 04.4 0.04 40.40.40 40.40.40 004 0.44 004 0.40 04.44.04 04.4 40.4 00.4040 00.4 0.00 40.4000 00.4 04.0 04.4 40.0 40.4 00.4 404 00.4 00 00 004 0.00 00.4 0.44 40.4 004 00.4 004 04.4 0.44 004 0.44 00.44.00 04.4 0.00 00.44.04 40.4 440 004 4.04 04.4 44.4 00.4040 044 0.04 404 0004 00.4 44.0 00.4 04.0 004 44.4 00.4 40.4 00 40 40.4 404 044 0.44 004 044 00.4004 S4 4.04 04.4 0.44 40.4 0.00 04.4 0.00 00.40.04 004 4.40 00.40.04 04.4 40.4 00.4 000 044 0.04 40.44044 004 04.0 00.4 00.0 40.4 04.4 00.4 04.0 404 00 00.4 044 044 0.04 404 404 00.4404 04.4 0.04 40.4 0.44 04.4 4.00 00.4 0.00 00.44.04 00.4 4.00 00.4 0.04 444 00.4 404 000 04.4 040 00.40444 00.4 04.0 40400.0 444 00.4 00.4 00.0 00 00 004 404 044 0.44 04.4 004 44.4004 04.4 4.04 00.4 0.44 00.4 0.00 44.40.00 004 4.44 00.4 0.40 404 0.04 44.4 004 40.4 040 40.40.44 00.40044 00.4 44.0 00.4 00.0 04.4 00.4 00.4 00.4 00 00 044 0.40 044 4.04 00.4 404 004 044 04.4 0.04 44.4 0.04 404 0.00 004 4.40 04.4 0.04 004 404 00.4 044 04.4 004 00.4000 00.4 0.00 004 004 44.4 04.0 40.4 40.4 44.4 40.4 40.4 00.4 40 40 40.4 044 04.40.04 004 004 00.4 404 44.4 0.04 04.4 0.04 044 0.00 004 0.40 044 4.04 04.4 404 04.44.04 04.4 00.4 40.4 000 04.4 4.00 004 0004 00.4 04.0 40.4 40.0 04.4 40.4 40.4 00.0 00 40 04.4 404 44.40.44 044 444 44.4044 00.4 4.04 04.4 0.44 00.4 4.00 04.4 0.04 40.4 0.04 00.4 044 00.40.44 044 00.0 444 040 04.4 0.00 004 000 40.4 04.0 40.4 00.4 044 00.4 40.4 00.0 00 40 004 4.00 044 0.04 00.4 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04.4404 04.4 0.04 004 040 04.4 04.0 00.4 00.0 004 004 044 04.4 04 00 404 0.00 04.40.04 40.4 044 04 04 00.4 0.04 04.4 4.04 404 0.44 044 0.04 04.40.04 00.40.00 00.4 4.44 44.4 40.4 00.4000 00.4 440 44.4 044 44.4 04.0 04.4 00.4 044 04.4 00.4 44.4 04 40 044 4.40 00.44.04 04.4 404 04 04 44.4 0.04 00.4 04.0 44.44.04 04.40.44 40.4 0.04 40.40.40 00.40.44 044 00.4 04.4 044 044 0.04 .404404 04.4 04.0 004 40.4 04.4 00.4 44.4 00.4 44 00 0 40.4 044 04.4 0.04 40.4 044 00.4 044 044.400 40.4 00.0 04.4 0.04 44.4 0.04 40.4 0.44 404 4.40 00.40.04 00.4 40.4 40.4 004 044 0.04 44.4004 044 04.0 004 00.4 04.4 00.4 00.4 00.4 00 40 00.4 0.00 44.40.04 044 044 04 04 00.4 44.0 044 00.0 04.4 0.04 044 0.04 004 0.44 00.40.00 00.4 0.44 44.4 00.4 44.4 004 04.4 0.04 04.4400 044 04.0 00.4 404 04.4 404 00.4 40.4 00 40 004 044 04.4 0.04 00.4 044 00.4004 04.4 04.0 004 4.04 04.40.04 044 0.44 00.4 0.44 00.4 4.00 004 0.44 04.4 04.4 404 444 04.44.40 04.4 004 04.4 04.0 00.4 00.4 44.4 00.4 04.4 00.4 00 00 00.44.00 04.40.04 04.04.00 40.0 400 404 00.4 00.4 00.0 404 4.04 00.4 0.04 04.40.04 44.40.40 00.40.04 04.4 00.4 00.4004 444 0.00 00.4404 00.4 00.0 40.0 04.0 04.4 00.4 40.4 00.4 44 00 00.4 044 44.44.04 004 0.00 004 004 00.4 00.0 04.4 00.0 40.4 0.04 00.4 4.04 404 0.04 00.40.00 004 4.44 004 04.4 40.4 004 00.4 0.00 00.4 000 00.4 04.0 00.4 04.4 44.4404 40.4 04.4 40 00 404 0.40 44.40.04 00.40.40 04 04 00.4 40.0 004 0.44 004 0.04 00.4 0.04 40.4 0.04 00.44.00 40.44.44 04.4 44.4 04.4 004 04.40.00 004 000 004 04.0 404 44.4 00.4 04.4 404 04.4 00 00 00.4 0.00 04.4 0.04 40.40.40 04 04 04.4 40.0 00.4 00.0 00.44.04 40.4 4.04 00.44.04 40.4 0:00 004 0.04 04.4 00.4 00.4004 44.40.00 00.4000 04.4 04.0 04.4 004 04.4 44.4 44.4 00.4 00 04 04.4 004 44.4 4.04 004 404 00.4 004 04.4 0.04 40.4 0.04 44.4 0.00 04.44.00 00.4 0.04 00.4 044 00.4 0.04 04.4 004 40.4000 40.4 0.04 004 4044 40.4 04.0 404 04.0 00404.4 00.4 40.0 00 04 00.4 00 04.40.04 00.4 00 04 04 40.4 00.0 00.4 04.0 00.4 0.44 04 04 40.4 0.04 004 4.40 00.4 4.04 04.4 044 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AD»: 0.400.403.5040 8.4024800 4044.3 04004000004500 $55 000024. otuuguwld 44.40418 8 SEDIMENTS OF CENTRAL GULF OF MEXICO “the correct expression of abundance—or an un- biased estimate of abundance—under all conditions” (M’iesch, 1967). Table 5 lists the estimated geo- chemical abundances for the combined strata of Holocene and Pleistocene age and may be compared directly to arithmetic means (geochemical cover- ages) reported in the literature (Schacklette and others, 1971) . As the arithmetic mean or geochemical abundance is important in determining geochemical cycles, geo- chemical variation is important in understanding the chemistry of the elements and in evaluating the sta- tistics used to classify them. The method used in calculating the arithmetic mean is based on the as- sumption that the population of values from which the sample values were drawn is lognormal. Figures 5 and 6 show the distribution of. each element; the base is the log scale used in reporting the results. From analyses for normality of the logs of each class for each element, using the procedure outlined by Krumbein and Graybill (1965, p. 177), it may be concluded that for all of the samples analyzed, iron,»~ boron, cobalt, and nickel are lognormally distrib— uted; for the Pleistocene samples, iron, calcium, titanium, cobalt, chromium, nickel, scandium, vana- dium, and zirconium are lognormally distributed. The remaining elements either lack sufficient data for such analyses or are close approximations of normal distributions, as determined graphically (Krumbein and Graybill,‘_1965, p. 177) . These analy- ses demonstrate that the distribution of the elements in the surficial sediment column of the Gulf of Mexi- co all appear to approximate lognormality, and thus the procedure used for calculating the arithmetic mean apparently is valid. The Pleistocene sediments show statistic-ally sig- nificant higher abundances for only four elements: boron, titanium, vanadium, and zirconium; the Holo- cene sediments show significantly higher abundances for only calcium and strontium. The pattern of ele- mental concentration in some way reflects the sedi- men-tological regime acting at the time of deposition. For example, the calcium and strontium enrichment in Holocene sediments indicates the known increase in pelagic sedimentation at this time, whereas the higher boron, vanadium, titanium, and zirconium values reflect the higher influx of hemipelagic sedi- ment during Pleistocene glacial periods. Comparison of the calculated average elemental abundances in this report and geochemical abun- dances reported in the literature shows significant differences. The sediments in the gulf basin may be classed as dominantly hemipelagic, but only the magnesium and the chromium concentrations ap- proach the values listed for hemipelagic sediments by Horn and Adams ( 1966). Some of the remaining elemental’concentrations compare on an individual- element basis with mobile belt sediments, shale, or pelagic sediments listed by Horn and Adams (1966) . However, the concentration-s of calcium, titanium, vanadium, or zirconium in these samples do not ap- proximate the concentration values of any of the sediment types characterized by Horn and Adams. TABLE 5.—Average element content in central Gulf of Mexico sediments [Data in parts per million; each average represents arithmetic means] Central basin sediments (This report) Worldwide averages of major sedimentary units (Horn and Adams, 1966) Element Total Holo— Upper Mobile _ “"33" “.2333 03333“- 5.... 33.3. 333.3. 33.33. 3...... samples samp es samples ments B ____________________ 59 47 62 12 79 25 56 11 71 Ba ___________________ 319 291 327 35 263 199 233 881 634 Be ___________________ 1 1 1 0.2 2 0.3 1 6 3 Ca ___________________ 45,090 69,100 43,130 272,000 22,000 22,200 26,900 27,700 83,300 Go ___________________ 20 21 20 0.2 8 0.5 5 38 26 Cr ___________________ 84 74 87 7 427 121 295 92 60 Cu ___________________ 23 20 23 4 47 15 34 150 106 Fe ___________________ 24,650 22,050 25,230 ‘8,660 39,600 21,000 31,100 50,100 32,400. La ___________________ 27 23 6 25 11 18 83 55 Mg __________________ 16,570 15,310 16,890 45,500 16,600 8,760 13,900 16,400 10,900 Mn __________________ 899 892 959 385 300 10 188 3,650 2,310 Ni ___________________ 40 36 40 13 33 3 21 152 110 Pb ___________________ 11 7 12 6 20 7 15 41 27 Sc ___________________ 12 9 12 1 11 1 7 23 14 Sr ___________________ 363 1,054 388 544 242 24 168 881 792 Ti ___________________ 1,840 1,570 1,900 389 4,520 - 2,100 3,430 5,660 3,670 V ____________________ 133 95 142 13 102 21 68 207 161 Y ____________________ 19 18 20 6 12 2 8 83 56 Zr ___________________ 97 87 100 18 144 206 160 145 1.21 RESULTS AND DISCUSSION 9 Mg L Ca Sr Ba La Y Zr L L L ‘ NL N L 1-2 0.1-10.0 0.07->20.00 10—7000 15-5000 20-70 10-50 20-500 PPM PERCENT PERCENT PPM PPM PPM PPM PPM 4. O m o fifl (D (D FREQUENCY PERCENT N 0 ON 0‘ 0 SC Ti V Cr Mn Fe 8 FREQUENCY PERCENT N O L NL NL NL L L 5-20 0.0015-l.5000 10—500 5—1000 5->5000 0.05->20.00 PPM PERCENT PPM PPM PPM PERCENT O 0“ 0 Cu B Pb Hg Co .3: O FREQUENCY PERCENT N o 5-700 5—500 5-1500 10-70 3-300 10—200 0.07-0.22 PPM PPM PPM PPM PPM PPM PPM FIGURE 5.—Frequency distribution of 21 elements for all samples taken on the central gulf basin. The horizontal scale is a log scale in which the values are reported by the analyst. L=less than the lower limit of detection by the analytical procedure, but present. N=none detected. Mg Ca [ Sr Ba La B Pb 6 .— Z Z Lu Lu 2) O on: w r E L L L L 1.0—15.o 0.2-50 0.3-2o.o 100—7000 20—5000 20-70 10—50 20—500 10-70 30-150 10—100 PPM PERCENT PERCENT PPM PPM PPM PPM PPM PPM PPM PPM Sc Ti v Cr Mn Fe [ Co Ni Cu >- 40 o I- i Z Z w Lu 3 U ‘ 8E 20 a: o. u. 0 ML L ' 5—20 0015—20000 10—500 10—1000 5-5000 0.2—7.0 5—100‘ #' 73—100 7-300 PPM PERCENT PPM PPM PPM PERCENT PPM PPM PPM FIGURE 6.—Frequency distribution of 20 elements for samples of Pleistocene age in the central gulf basin. The horizontal scale is a log scale in which the values are reported by the analyst. L=less than the lower limit of detection by the analytical procedure, but present. N=none detected. REGIONAL VARIATIONS AND GEOCHEMICAL 131113 The factors presefitly consideped to be re. COHERENCE sponsible for the chemical imprint of sediments are: The chemical character of marine sediments is the nature of the source rock, the environment at the determined by no-nequilibrium processes which com- source, the nature 0f the transporting medium, the pl'icate the solving of sedimentary geochemical prob— environment at the depositional site, the nature and 10 activity of the biomass at the site of deposition, tec- tonic activity, and ,diagenetic redistribution. Of these, probably the most important are the source rock and environment at the source. Hirst (1962), J enne (1968), Krauskopf (1956, 1957), and Carroll (1958) have shown that, once in transit, most metals tend to remain physically associated with clay-size material. Thus, regional concentration patterns of metals associated with the clay-size materials may provide information about the source. The data presented in this report show some re- gional variations of elemental abundances in the basin sediments of the Gulf of Mexico. For some of the mapped elements, h0wever, the variation is only a matter of one “bracket of determination,” in which case the value of these elements as a source indicator is considered poo-r. On the other hand, those elements whose distribution is spread, more or less evenly, through several brackets of determination have con- siderable potential as source indicators. Of the 17 elements mapped, only 4—calcium, strontium, chromium, and vanadium—appear to meet this re- quirement. However, before these elements can be SEDIMENTS OF CENTRAL GULF OF MEXICO definitely defined as source indicators, some under- standing of the geochemistry of these elements is necessary. The determination of the geochemical coherence of the elements aids in this by relating these elements to major elements whose marine chemistry is better understood. Geochemically coherent elements as described by Rankama and Sahama (1950) are those elements “which are always found together in nature.” This relationship does not necessarily imply similarity of chemical behavior or chemical coherence in the en- vironment in which the elements are or have been; all that is implied is that the elements do tend to be associated in the sediment. The degree of geochemi- cal coherence is most conveniently obtained by the calculation of correlation coefficients—those statisti- cal par-ameter-s Which “measure” the reliability of one variable in predicting another. These parameters were calculated on the logarithms of the reported analytical values, and data pairs in which one or both of the values are beyond the limits of detection were ignored. In the cases where data have been skipped over, the data are derived from censored TABLE 6.—Com'elatlon coefficients among 20 elements based on all sediment samples taken during the cruise of the USNS Kane in 1969 [The numbers above the diagonal are the correlation coefficients (1‘); which 1' was calculated. The discrepancy between the total listed here eluding 51 grab samples] the numbers below the diagonal represent the number of element pairs on and the total given in text is because this table is based on all samples in- Fe 0.50 —0.08 0.59 0.43 0.52 0.52 0.03 0.51 0.52 0.44 0.46 -0.01 0.47 0.17 0.67 -0.28 0.76 0.62 0.55 Mg 2533 Mg 0.26 0.45 0.43 0.46 0.37 -0.14 0.32 0.47 0.40 0.37 0.03 0.37 0.10 0.49 —0.08 0.58 0.53 0.38 Ca 2496 2497 Ca —0.18 0.08 -0.28 -0.17 -0.26 0.15 0.23 0.02 0.05 0.08 0.28 0.07 0.02 0.72 —O.16 0.10 -0.31 Ti 2533 2535 2497 Ti 0.34 0.51 0.54 0.04 0.30 0.37 0.41 0.43 0.06 0.33 0.05 0.56 —0.36 0.59. 0.58 0.68 Mn 2515 2517 2479 2517 Mn 0.42 0.40 —0.02 0.34 0.23 0.40 0.28 0.01 0.23 0.16 0.36 -0.13 0.46 0.36 0.24 B 2531 2533 2495 2531 2513 B 0.39 0.10 0.10 0.15 0.42 0.27 0.06 0.10 0.02 0.36 -0.45 0.61 0.30 0.47 Ba 2500 2501 2467 2501 2483 2499 Ba 0.01 0.32 0.29 0.40 0.40 0.01 0.14 0.20 0.48 —0.43 0.59 0.53 0.63 Be 2431 2431 2420 2431 2415 2429 2413 Be 0.04 —0.10 0.07 —0.08 -0.03 0.03 0.07 -0.07 -0.27 0.05 -0.04 0.16 Co 2509 2510 2478 2510 2492 2508 2483 2415 Co 0.47 0.41 0.30 —0.03 0.65 0.28 0.52 -0.02 0.43 0.46 0.27 Cr 2521 2523 2486 2523 2505 2521 2491 2419 2502 Cr 0.32 0.37 0.01 0.72 0.14 0.62 0.11 0.58 0.53 0.29 Cu 2528 2530 2494 2529 2511 2528 2499 2428 2507 2518 Cu 0.25 0.03 0.38 0.34 0.47 -0.16 0.54 0.36 0.32 La 2308 2308 2282 2308 2293 2307 2279 2244 2292 2297 2305 La 0.02 0.27 0.24 0.43 -0.08 0.47 0.56 0.38 N1 2528 2529 2492 2529 2511 2527 2497 2428 2509 2519 2525 2305 692 Ni 0.20 0.57 0.19 0.46 0.42 0.19 Pb 2193 2193 2176 2193 2177 2192 2190 2151 2182 2182 2191 2078 670 2191 Pb 0.23 0.00 0.18 0.24 0.10 Sc 2494 2494 2464 2494 2477 2493 2486 2413 2479 2484 2492 2283 694 2492 2188 Sc -0.16 0.73 0.63 0.49 Sr 2261 2263 2232 2262 2244 2260 2249 2180 2242 2252 2256 2106 679 2258 2060 2245 Sr —0.39 -0.14 10.51 V 2529 2531 2493 2531 2513 2527 2500 2429 2508 2521 2526 2306 693 2527 2190 2493 2261 V 0.63 0.65 Y 2523 2523 2486 2523 2505 2521 2496 2426 2506 2511 2519 2303 694 2520 2191 2492 2257 2521 Y 0.56 Zr 2526 2526 2490 2526 2508 2524 2498 2429 2504 2514 2521 2304 694 2522 2192 2494 2259 2523 2521 Zr TABLE 7.—-—Correlation eoeflicients for the Pleistocene samples [The numbers above the diagonal are the correlation coefficients (1); the numbers below the diagonal represent the number of element pairs on which 1' was calculated] Fe 0.55 0.00 0.61 0.38 0.48 0.56 -0.03 0.51 0.54 0.37 0.59 —0.01 0.44 0.15 0.66 -0.21 0.76 0.62 0.54 M3 2072 Mg 0.24 0.48 0.42 0.40 0.51 —0.19 0.33 0.43 0.34 0.52 0.04 0.29 0.11 0.47 —0.07 0.55 0.59 0.44 Ca 2060 2060 Ca —0.14 0.14 -0.35 -0.03 —0.23 0.25 0.29 0.05 0.14 0.11 0.34 0.13 0.10 0.72 -0.14 0.21 -0.22 Ti 2072 2072 2060 Ti 0.25 0.48 0.53 —0.02 0.28 0.35 0.32 0.53 0.06 0.28 0.09 0.53 —0.30 0.67 0.56 0.65 Mn 2062 2062 2050 2062 Mn 0.35 0.40, —0.07 0.32 0.15 0.32 0.34 0.01 0.16 0.14 0.31 —0.09 0.38 0.34 0.19 B 2072 2072 2060 2072 2062 B 0.40 0.06 0.06 0.06 0.30 0.29 0.08 -0.05 0.01 0.27 -0.48 0.54 0.25 0.49 Ba 2069 2069 2057 2069 2059 2069 Ba —0.05 0.36 0.34 0.39 0.52 0.01 0.22 0.21 0.49 -0.33 0.61 0.56 0.61 Be 2046 2046 2040 2046 2036 2046 2043 Be 0.01 -0.14 0.04 -0.14 —0.03 -0.07 0.05 0.02 -0.24 —0.02 —O.11 0.11 Co 2070 2070 2058 2070 2060 2070 2067 2045 Co 0.52 0.39 0.40 -0.40 0.65 0.28 0.53 0.07 0.44 0.48 0.25 Cr 2070 2070 2058 2070 2060 2070 2067 2044 2068 Cr 0.26 0.49 0.01 0.72 0.19 0.63 0.19 0.53 0.55 0.28 Cu 2072 2072 2060 2072 2062 2072 2069 .2046 2070 2070 Cu 0.31 0.06 0.33 0.35 0.39 -0.08 0.43 0.31 0.26 La 1917 1917 1906 1917 1907 1917 1914 1894 1916 1915 1917 La 0.02 0.38 0.25 0.57 —0.04 0.62 0.71 0.44 Ni 2072 2072 2060 2072 2062 2072 2069 2046 2070 2070 2072 1917 597 Ni 0.26 0.55 0.28 0.40 0.43 0.15 Pb 1862 1862 1852 1862 1852 1862 1862 1840 1861 1860 1862 1764 580 1862 Pb 0.22 0.05 0.18 0.23 0.10 Sc 2067 2067 2055 2067 2057 2067 2066 2041 2065 2065 2067 1912 597 2067 1860 Sc -0.06 0.69 0.65 0.47 St 1853 1853 1843 1853 1843 1853 1853 1831 1851 1851 1853 1762 586 1853 1749 1853 Sr -0.35 -0.02 —0.44 V 2072 2072 2060 2072 2062 2072 2069 2046 2070 2070 2072 1917 597 2072 1862 2067 1853 V 0.64 0.64 Y 2071 2071 2059 2071 2061 2071 2068 2046 2070 2069 2071 1917 597 2071 1862 2066 1852 2071 Y 0.52 Zr 2072 2072 2060 2072 2062 2072 2069 2046 2070 2070 2072 1917 597 2072 1862 2067 1853 2072 2071 Zr RESULTS AND DISCUSSION distributions and the correlation coefficients should be considered as “indices of association” rather than true correlation coefi‘icients (A. T. Miesch, written commun., 1970). The correlation coefl‘icients for all samples and for those only of Pleistocene age are listed in tables 6 and 7, respectively. Further evaluation for geochemical coherence may be made from R-mode (between variables) factor analysis (Imbrie, 1963). In this analysis, the data are assumed to be derived from a system which. consists of a number of unknown causal influences, a notion of cause and effect Which is treated strictly mathematically. However, geologic evaluation of the output of this analysis aIIOWS for the determination of the number of causal influences needed to account for the observed variations and for the identity of these influences. For a detailed discussion of factor 11 analysis the reader is directed to the report of Imbrie (1963). Based on the correlation coefficients and R-mode factor analysis, the element concentrations were classed into three geochemically coherent groups: the iron-vanadium group (I) , the calcium-strontium group (II), and the beryllium-niobium-lead group (III). The strongest correlations in the total data set were found between iron and vanadium and calcium and strontium. Thirteen elements (B, Ba, Cr, Co, Cu, La, Mg, Mn, Ni, Sc, Ti, Y, and Zr) were found to have significant correlation with the iron-vanadi- um couple. Factor analysis indicated that a division of this group into four sub-classes could be made (fig. 7). All the elements in group I, except those in the manganese subclass, have high correlation with the iron-vanadium couple. The‘manganese subclass, Ba Ti 63) Cr Mg La Zr / Ni / Y C f \S‘T ° Mg Subclass Ti Subclass Cr Subclass @ Mn Subclass GROUP M Q @ GROUP m FIGURE 7.—Schematic of element associations based on the calculated correlation coefficients and factor analysis. Double line ties two elements having an ('r) correlation coefficient elements with an (1') between 0.70—0.50. for all samples greater than 0.70; a single line ties those 12 SEDIMENTS OF CENTRAL GULF OF MEXICO the bastard of group I, shows only moderate correla- tion with iron or vanadium and is placed. in this group because of the reported association of iron and manganese (Krauskopf, 1956). The elements in group III, beryllium, niobium, and lead, have either no significant-or very weak correlations between themselves and all other elements determined. The lack of correlation and geochemical coherence of the elements in the third group with any other element is probably because of their truncated distribution. IRON-VANADIUM GROUP The group I elements are predominantly associ- ated with the detrital phases of marine sediments (Hirst, 1962). Catego-rizing the group I elements into the subclasses allows for geological judgment about the form in which these elements exist. For example, those elements in the magnesium subclass are most likely associated within clay' minerals (Hirst, 1962) ; the titanium and the chromium sub- classes, on the other hand, suggest an association with such detrital phases as heavy minerals. The areal distribution of the group I elements is best represented by vanadium. On the Mississippi Fan, vanadium has an almost 150 ppm unimodal dis- tribution (pl. 1). Next to the fan, in the lower reaches of the De Soto Canyon (core 67), the sedi- ment has a significantly lower average vanadium content. Toward the Florida Straits the patterns become confused, the vanadium distribution in the core 40 at the base of the lower fan exhibiting a scattered distribution and a character simi- lar to the sediment in the De Soto Canyon area. The sediments of these areas contain an abundance of re- worked Cretaceous foraminifera (Huang, 1969) which does suggest a De Soto Canyon source, the material having been slump-ed into its present posi- tion. In the three remaining cores on the southeast- erly line (8, 26 and 28), the sediments in the first‘ and third have a chemical character similar to those of the Mississippi Fan. However, the sediment in core 26 has a chemical nature nearly identical to that of core 68, taken nearest the mouth of the Mississip- pi River. This suggests that, at least chemically, the sediments are similar at both sites and are possibly from a similar source. It is noted that these two cores also show a unique similarity in their clay mineralogy (Ferrell and others, 1971). The vanadium map also shows that the sediments on the perimeter of the basin have the lowest va- nadium content, Whereas those in the abyssal section of the basin have the highest values, with the excep- tion of sediment in the vicinity of the lower Cam- peche Canyon. These sediments, represented by cores 139, 141B, 143 and 144, have extraordinarily low vanadium values owing to dilution of carbonate-rich vanadium-poor detritus from the Campeche Bank. This influx of Campeche Bank sediment is also ap- parent in the sediments on the abyssal plain (43) at the northeastern edge of the Campeche Bank. Examination of the maps of the rest of the group I elements shows that they have distributional pat- terns nearly identical to vanadium; that is, the sedi- ments on the perimeter of the gulf basin have the lower concentrations of most elements, and the sedi- ments in the abyssal region have the higher. The sediments near the western edge of the Campeche Bank reflect dilution by carbonate sediment. Cores 68 and 26 from the Mississippi River and Yucatan Straits, respectively, exhibit a chemical similarity which suggests similar origin. Also, on many maps 40 can be chemically differentiated. Chemical composition of the sediment in the northern and eastern gulf does show significant regional variation, but is nevertheless a questionable basis for determination of the ultimate source of this area’s sediment. As mentioned previously, the Miss- issippi River is the major source of sediment, and apparently has been for at least the past 2 million years, the maximum possible age of the sediment examined. If the variations in most of the cores do not reflect the source, the question arises as to What could produce the definite regional pattern of low elemental concentration on the perimeter to high in the central basin. As mentioned above, the elements of group I may be associated with different phases of detrital sediment. To a degree this is the case, but as pointed out by many investigations (Hirst, 1962; Chester, 1965) , the clay-size material seems to be the detrital material with the highest concentration of these elements. If so, then the region with the high- est content o~f clay-size material would have the highest concentration of metals in the Gulf of Mexi- co. Figure 8 shows the distribution of clay-size ma- terial based on data published by Bouma, Bryant, and Davies (1971). In general, the diagram shows that the cores from deeper, more central areas of the basin have a higher clay content, as well as high metal concentrations. This seems to uphold the find- ings of Hirst (1962) and Chester (1965). Even though it is somewhat questionable to deter- mine the ultimate source of the sediment in the east- ern and northern gulf by the sediment’s chemical character, in the southwestern gulf there is sub- RESULTS AND DISCUSSION 13 98° 96' I l 30- _ UNITED STATES 26' 24’ 22' YUCATAN PENINSULA 28' 24' 22' PERCENT CLAY 20- - 20' 40 50 60 30 70 20 80 18‘ _ . 10 90 18 o loo 200 3oo 400 500 KILOMETRES fl 0 I l I l l l V I ‘ ' l I l o 100 200 300 MILES 16. I I I I I I I I I 16. 98’ 96‘ 94- 92- 90' 88‘ 86‘ 84° 82‘ so- FIGURE 8.—Circu1ar histogram of frequency versus clay percentage in cores from the central gulf basin. The number in the center of each graph is the number of analyses made for that core. The scale is present at the lower right. Data from Bouma and others, 1971. stantial evidence that the elemental trends are in- dicative of source areas. In the Bay of Campeche the sediments nearest land have high chromium, nickel, and cobalt concentrations which decrease seaward. This gradient reflects a landward source in the vol- canic fields on the isthmus of Tehuanatepec. Similar- ly, carbonate detritus low in trace metal from the ‘ Campeche Bank produces a dilution effect decreasing the concentration of all elements in sediments (Cores 139, 141, 143, 144) off the northwestern corner of the Campeche Bank. These trends, then, suggest that under some circumstances the semiquantitative data are of value as indicators of source regions, particu- larly where the regions are significantly different in chemical character. MANGANESE SUBCLASS Distribution—The weak correlation between manganese and the other elements of group I is not apparent when comparisons are made of their pat— terns oif areal distribution (for example, comparing manganese with vanadium in pl. 1). The differences become apparent, how-ever, when the vertical dis- tribution of manganese is compared to that of other elements, for example, iron (figs. 9 and 10). A few 14 SEDIMENTS OF CENTRAL GULF OF MEXICO 0 100 DEPTH, IN CENTI M ETRES I'! ,.. ,....~ \. '_-’\./'\. f\._,- \- l‘. 1 1 000 4.0 6.0 PERCENT 000 2.0 4.0 6.0 PERCENT. 1°00 20 4.0 6.0 PERCENY 4000 6000 PPM 2000 4000 6000 PPM 2000 4000 6000 PPM m 0.10 Mn/Fe 0.01 0.10 Mn/Fe 0.01 0.10 0 100 . 200 (I) u E 300 E .: 400 E o 500 5 - 600 E s 700 CORE ° . 40 800 'V 900 1000 1 ‘ ‘ " Fe 0 2.0 4.0 6.0 PERCENT 4.0 , 6.0 PERCENT Fe 0 2.0 4.0 6.0 PERCENT Mn 0 2000 4000 6000PPM 4000 6000PPM Mn0 2000 4000 soooPPu Mn/Fe 0.01 0.10 Mn/Fe 0.01 0.10 Mn/Fe 0.01 0.10 FIGURE 9.—The distribution of iron, manganese, and Mn/ Fe ratio with depth in cores raised from a southeast-northwest transect in the eastern gulf basin. cores (68, 97, 96, and 93) in addition to the more typical section which ShOWS the highest manganese concentration in the upper metre have manganese- rich zones at depth. Those few cores which do not show the flag type of vertical manganese distribu- tion (fig. 11) appear to be sedimentologically unique. For example, core 40 on the lower Mississippi Fan has been described as unique by Bouma, Bryant, and Davis (1971) and Huang (1969) because of its lack of Holocene surface sediment, its internal structure, and its texture. This cere probably contains sedi— ment implaced by mass transport rather than by the regular se-dimentological processes of this section of the gulf. As a consequence, the chemical nature of the sediment is unique for the area and no high man- ganese concentrations are present. Similar descrip- tions may be applied to cores 139, 143, and 144 in the southwestern gulf and cores 102, 114, and 150 on the northern rim of the gulf basin, all of which lack 5 the characteristic flag distribution of manganese. Distribution over Holocene-Pleistocene boundary. —Based on paleontologic (Kennett and Huddleston, 1972; Ludwig, 1971), geochemical (Newman and others, 1973), and sedimentologic (Bouma and oth- RESULTS AND l 000 Fe 0 2.0 4.0 60 PERCENT Mn 0 2000 4000 6000 PPM Mn/Fe 0,01 0.10 4.0 60 PERCENT 4000 6000 PPM Mn/Fe 0.01 0.10 Mn/Fe 0.01 DISCUSSION 15 EXPLANATION Foraminifera Silty clay Thick bedding Thin bedding Graded bedding 2,0 60 PERCENT 2000 6000 PPM lUEil 0.10 i Inclin‘ed bedding Convoluted bedding %Pk Burrowing 2.0 4.0 6.0 PERCENT 2000 6000 PPM 0.10 FIGURE 9. -—Continued. ers, 1971) evidence, the Holocene-Pleistocene boun- dary was estimated with confidence in 27 cores. Fortunately, these cores are spread throughout the basin, and chemical comparisons can be made with both age and different physiographic regions. In' all but one of these cores (96), the spectrographically determined manganese was found to be highest in the Holocene sediments (table 8). Regionally, the Holocene sediments highest in manganese concentration are adjacent to the Miss- issippi delta, in the southernmost sections of the Bay of Campeche, and in the western portion of the abyssal plain; the highest and most extensive con- centrations occur in the area mentioned last. By con- trast, the highest manganese concentration in the Pleistocene sediments occurs adjacent to the Miss- issippi delta and in the west-northwest region of the basin. Selective leaching of manganese by the analytical procedure mentioned previously accounted for near- ly all the manganese from the sediment. Comparison of spectrographically determined manganese and the authigenic manganese showed that most man- ganese is in a hydrogenous form (fig. 12). Marine geochemistry.——The marine chemistry of manganese has been the subject of many recent re- reports (Krauskopf, 1957; Lynn and Bonatti, 1965; Bostro'm, 1967; Chester and Hughes, 1967; Bender and others, 1970; Bender, 1971; Bonatti and others, 1971; Bischoff and Sayles, 1972). These and many previous studies provide a basic understanding of a general model of the marine chemistry of man- ganese. The element, either in the ionic form or as an hydroxide film adhering to fine detrital material, enters the sea via rivers. Once in the basic marine environment, manganese which is in the ionic state 16 SEDIMENTS OF CENTRAL GULF OF MEXICO 1000 60 PERCENT 6.0 PERCENT 6000 PPM 2000 4000 6000 PPM 0.10 Mn/Fe 0.01 0.10 (I) LLI n: .— Lu 2 ,2 2 M1 0 E :15 1— D. u D 1000 . 4.0 6.0 PERCENT 1000 l—+——+—1——1——1——1 6000 PPM Mn/Fe 0.01 0.10 Mn/Fe 0.01 o o :‘kaf. '.':u--.. 100 100 (9 “~- . _ F~ \ 200 200 ' (I) t“:J 300 ‘ ,_ 300 L11 E 400 400 '2 CORE 144 3 500 500 Z '. 600 600 E a 700 700 W. Lu 0 800 ' 800 Em 900 900 1000 Fe 0 2‘0 410 60 PERCENT Fe 0 20 Mn 0 2000 4000 6000 PPM Mn 0 2000 Mn/Fe 0.01 0.10 Mn/Fe 0.01 CORE 141 B 4.0 6.0 PERCENT . 4.0 6.0 PERCENT 4ooo soooPPM Mn 0 2000 4000 6000 PPM rm-l—v—mfl 0.10 Mn/Fe 0.01 010 FIGURE 10.—The distribution of iron, manganese, and the Mn/ Fe ratio with depth in cores raised from a north-south transect in the western gulf basin. hydrolizes and precipitates to the sea floor and car- ries with it many metals it has scavenged. The high manganese concentration near the delta of the Miss- issippi is probably the result of this activity. The distribution of the adsorbed form of manganese will be wholly influenced by the sedimentolo-gic environ- ment; the regions of the highest clay/concentration will have the highest manganese concentration. Besides continental erosion, another source of manganese in the sea is volcanic activity. This source, however, may be neglected in the Gulf of Mexico because there is no evidence of any signifi- cant basin and submarine volcanic activity in the later part of the Pleistocene. The decay of organic detritus in the deposited sediment produces a reducing chemical environment. Under such conditions, manganese is reduced to the soluble Mn+2 species and migrates by ionic diffusion toward the surface. The other ions associated with manganese tend to form sulfides and remain nearly in place in the sediment column (unless the redox potential is extremely low). So manganese tends to be concentrated near the surface, the lower boundary of the enriched zone being marked by a decrease in RESULTS AND DISCUSSION 17 EXPLANATION .‘o Foraminifera Foraminifera hash ‘0 5 Q l Sig Silty clay 1:: Thick bedding 2.0 4.0 6.0 PERCENT 4.0 6.0 PERCENT E Thin bedding 2000 4000 5000 PPM 4000 6000 PPM 32 '"dgggéfiiéhi" ”we °'°‘ °“° Graded bedding .1. Inclined bedding .0. Convoluted bedding / Burrowing é? Mottled . Fe _ ..... Mn Mn/Fe 2.0 4.0 6.0 PERCENT Fe 0 2000 4000 m0 PPM Mn 0 I—rv-v-rv-wfi—‘r—fi'fi" Mn/Fe 0.01 0.10 2.0 4.0 6.0 PERCENY 2000 4000 6000 PPM [Tn-r—v—r—r—Tm Mn/Fe 0.01 0.10 FIGURE 10.-—-Continued. the oxidation potential. Estimates of the redox po- tential and manganese distribution in the sediments of the gulf show a general agreement with the model (fig. 13) . Detailed manganese analyses in the upper metre of four representative cores from the major provinces of the gulf also demonstrate good agree- ment with the model (figs. 14 and 15). Figure 14 also shows the almost independent relationship of iron and manganese. Other elements in the sedi- ments containing greater than 1,000 ppm manganese (table 4) undergo no significant enrichment in con- centration in the high manganese sediments. In only one core in the western gulf is there the slightest evi- dence of comigration of iron and other elements with manganese. In some cores, particularly in the western gulf, manganese-rich zones are found at depth (28 of fig. 9 and 93 and 96 of fig. 10). These are interpreted as “fossil” oxidized zones which were buried by rapid deposition during the glacial maxima of the Pleistocene. CALCIUM-STRONTIUM GROUP The distribution of these group II elements is in- trinsically related to the distribution of carbonates, the predominant association of these elements. ,In the gulf basin the calcium content in the sediment 18 SEDIMENTS OF CENTRAL GULF OF MEXICO 98' 96' 94' 92' 90- m I I I 30- _ UNITED STATES 28' 26' 24' 22' YUCATAN PENINSULA 80' — 30' — 28' 26‘ 24’ 22' MAN GAN ESE vs DEPTH PERCENT 20' MANGANESE — 20' O 0.5 1.0 0 z ‘3 1 IE EN 2 13' W 35 — 18° 3 o 100 200 300 400 500 KILOMETRES 3 LI I l I . I I I I I I I I I I o 100 200 300 MILES 16. I I I I I I I I I 16. 98' ’ 96' 94' 92' 90' 88' 86' 84' 82" 80' FIGURE 11.—Vertical distribution of spectrographically determined manganese from the top 3 m of 46 cores. ranges from 0.25 to greater than 20 percent com- position. The carbonates in the gulf basin were either deposited as carbonate detritus washed from the Florida or Yucatan shelves or derived from planktonic carbonate-secreting organisms. In the south-central abyssal region of the gulf, Davies (1968) found carbonate-rich zones in cores contain- ing shallow-water organisms and suggested that much of the carbonate sediments in this region were derived from the Campeche Bank. The pelagic con- tribution of calcium to the sediment is primarily foraminiferal tests (Kennett and Huddleston, 1972) ; the tests of other carbonate secreting organisms (pterepods and coccoliths) are present in insignifi- cant concentrations. The only ydetrit‘al carbonate layers occur in the western gulf. Like calcium, strontium in marine sediments is predominantly associated with carbonates. Chemi- cally similar to calcium, strontium substitutes for calcium in carbonates; however, being somewhat larger than calcium (Ca+2 has an octahedral radius of 0.99 A, and strontium has a radius of 1.12 A), strontium is preferentially incorporated into the more open aragonite carbonate structure. Turekian (1964) reported that pelagic Foraminifera range from 700 to 1,500 ppm strontium, whereas coral and many other shallow-water carbonates average 8,000 ppm strontium. Mineralogically this is predictable because all pelagic Foraminifera are calcitic, and RESULTS AND DISCUSSION 19 2000 I I I Z 0 I :I . :‘ 2 E t 1 “- 1500 — . _ m 0 E . a E I ' . 'o 2 __ , 3 <3 ' ' s g! 1000 — i - . — _.I I g o < 3/' ° 3 S F ‘ 8 0. K o 500 — I _ (I) m < o I 5 8 o b- < 0 l | l o ' 500 1000 1500 2000 SPECTROGRAPHIC ANALYSIS. IN PARTS PER MILLION FIGURE 12.—Comparison of manganese determined by atomic absorption analysis of leached material and by spectro— graphic analysis of whole samples. TABLE 8.—Average manganese content of the, total sediment and of the sediment on a carbonate-free basis (CFB) for those cores for which the Holocene-Pleistocene boundary has been defined [The investigator on whose data the Holocene boundary was primarily established: L=Ludwig (1971). KzKennett and Huddleston (1972). N=Newman and others (1973).] Holo— Holocene Pleistocene Core cene Bound- Total CFB Total CFB ary Its/g ug/g Its/g ,ug/g 8 ______ 67 L 1,188 1,284 722 767 28 ______ 60 L 815 913 586 593 44 ______ 105 L 1,236 1,482 736 750 47 ______ 80 L 972 1,020 586 597 57 ______ 24 L 847 1,006 815 840 60 ______ 40 L 857 958 934 989 62 ______ 60 L 1,465 1,562 652 680 68 ______ 70 L 2,173 2,739 1,423 1,489 83 ______ 140 L 1,385 1,875 1,295 1,336 84 ______ 38 L 1,934 2.295 826 857 87 ______ 80 N 802 1,687 767 791 91 ______ 210 N 1,607 1,909 968 1,496 92 ______ 100 L 2,090 2,215 847 878 93 ______ 100 L 1,416 1,777 743 763 94 ______ 240 N 1,260 1,500 697 718 96 ______ 250 N 1,152 1,239 1,715 1,861 97 ______ 300 K 1,708 1,913 1,437 1,500 111 ______ 90 L 2,187 2,427 645 701 115 ______ 105 K 2,229 2,381 704 732 120 ______ 80 K 2,302 2,972 1,225 1,295 125 ______ 105 K 1,243 1,322 902 968 131 ______ 60 K 1,618 1,767 687 753 138 ______ 125 K 1,486 1,625 767 836 141 ______ 120 K 1,385 1,472 409 461 146 ______ 100 N 1,392 1,482 618 628 147 ______ 110 K 1,829 1,940 690 715 150 ______ 150 N 982 1,048 O EXPLANATION m 39.9.: Foraminiferal O: 2 ooze m .—.— . E ___.- Sllty clay E 3 CE] Thick bedding I E a Thin bedding in D 4 pH 6.5 7.0 7.5 8.0 FIGURE 13.—Manganese, emv, and pH in the upper section of core 28. most corals and shallow water carbonates are com- posed of aragonite. The shallow—water or pelagic origins of the carbonate layers in the gulf may be differentiated by the calcium/ strontium ratio. High strontium content with a Ca/Sr ratio of approxi- mately 50 is indicative of a shallow-water source; low strontium content with a Ca/ Sr ranging between 250 and 600 is characteristic of a pelagic source. The distribution of calcium and strontium in cores from the western gulf is shown in figure 16. These cores were taken along long 93° W. and represent a section across many environments: the northern Continental Rise (111); the abyssal plain (97, 96, 93, 91); the lower C-ampeche Canyon (144, 143, 141B) ; and the Mexican Continental Slope (138, 136). The average calcium content as represented in these cores is higher than those taken in the east- ern gulf because of the reduced sedimentologic in- fluence of the Mississippi River which allows pelagic processes to play a larger role. Seven of the 11 cores (10 of which are shown in fig. 16) have well-defined carbonate layers. In the cores taken near the Cam- peche platform, the strontium concentration exceeds the upper limit of detection. These strontium-rich layers are interpreted to contain carbonate turbidites similar to those reported by Davies (1968). In cores toward the north, some low—Ca/Sr—ratio zones are indicative of shallow-water material but are less numerous. Samples from the southern cores having the high- est strontium content were X-rayed to determine their aragonite/calcite ratios and their ages (table 9). These layers contained approximately twice as 20 SEDIMENTS OF CENTRAL GULF OF MEXICO L‘. I1 ‘. I I-..__'II 1' “L, Il ' ijxw-U” “I I a) I Lu ‘. E I “J I g a '5 I w 60 I 0 \ ‘ I 3 70 ‘\ E x" a 80 .V I? O . F 9 1" / ,1 _ I, “H... 100 1’ “‘-~.I ‘-. I ____ I I .51 110 M I . .- | ,. I ,1" I I | i I I I ' . : 1 _,...I EXPLANATION !.-~ - - 1 foe Foramlnlfera CORE 125 I CORE 93 _ ‘-.,| 2Q Mottllng 1 I I I 1 1 ' l l E‘ Thin bedding 1 —_-_— . I/ I r: Sllty clay I l 4.. SH 1,} : E+ Marl xx! 1? i Burrowing ' t if II (—) lndistinct contact . / . ' F _ _ _ I _,r i , l . . {3 '~.._: 40?o_-a_ 4» I‘ 1‘ _ Manganese 0: {I -o o— \ I I I— I :79: I 13-. I Iron g r I. 50-'_' : 1 ' 1' I: 1 i ' _ I ”I I ---- CaC03 E .1. I I I" I . \ "~. 0 II I'-._ I 2 1‘ "21 ,i E /1 “1;; 7o 3 —II If 1’ a I II , a 3" \ "-I "1 i o f f: x I" 1 I31 9 ’ I I" I - I I I II I. .1 '. l -. I I I “0 ‘1 I1 CORE 84 L CORE 62 I I I I | I I I I I I l I 0 500 1000 5000 10,000 0 50 100 0 500 1000 500010000 0 50 100 150 MANGANESE, IN PPM CaCO3, IN PERCENT MANGANESE, IN PPM CaCOa, IN PERCENT 1000 3000 5000 1000 3000 5000 IRON, IN PPM IRON, IN PPM FIGURE 14.—Detailed analyses for manganese, iron, and calcium from the upper metre of four cores from the major provinces of the Gulf of Mexico. The line H/P is the estimated position of the Holocene-Pleistocene boundary as determined by Ludwig (1971) (L) or Kennett and Huddleston (1972) (K). CONCLUSION ‘l I I I .1 m l Lu I E 1 Lu 2 . l +— s .' 0 ........ t} E ..... Ii 15 / z r N a I: t—Cacoa CORE 28 0 50 100 eaco,, IN PERCENT 0 500 1000 500010000 MANGANESE, IN PPM |_.1__1__J 1000 2000 3000 4000 IRON, IN PPM EXPLANATION 305% Foraminifera iii—Z Silty clay 2 Thin bedding (—3 Indistinct contact .1— .1— -‘-_a Marl FIGURE 15.——Distribution of manganese, iron, and calcium between 500- and 630-m depth in core 28. much aragonite as calcite further evidence of a shal- low-water origin of the carbonate. Um/Th230 dating on these samples indicated an age of approximately 30,000 years. Those ages older than this can be brought into concordance by correcting for detrital thorium on the basis of the carbonate content. Thus, the carbonate layers in these cores were deposited at least 30,000 B.P. In core 141B, the synchronous de- position of nearly 6 m of carbonate must be the 21 result of mass transport processes. Paleontological work on this core (Kennett and Huddleston, 1972) shows that this zone is completely “reworked,” thus supporting the mass—transport interpretation. CONCLUSION The semiquantitative analyses of sediments from the Gulf of Mexico have provided good and detailed data on the marine distribution of some trace and minor elements. The average elemental content of the sediment, as determined by this method, was found to be significantly different from that of simi- lar sediment types reported in the literature (Horn and Adams, 1966). Whether or not this difference is due to the method of analysis cannot be evaluated at this time. However, these data do provide useful in- formation for making comparisons of trace-element content between recent sediments and those of Pleis- tocene and Holocene age. Analyses of the distribu- tion of individual elements of all samples demon- strate that most elements are approximately lognor- mally distributed; this is an important consideration in determining the geochemical cycle of elements and in deriving mathematical models to describe the elemental distribution. Statistical analyses of the data allowed the group- ing of elements according to geochemical coherence. The distribution of these groupings demonstrated that many elements (for example, iron, vanadium, chromium, magnesium, cobalt, titanium, and so forth) are intimately associated with detrital clay material. Manganese, an element showing a statis- tically weak association with the above elements, was found to be sensitive to postdeposition chemical pressures and was redistributed according to the chemical environment within the sediment. The dis- tribution of; calcium/strontium ratios provided use- ful criteria for determining the source of carbonate- rich sediments. TABLE 9.—Carbonate uranium-thorium disequilibrium [The ratio between uranium isotopes is in activity units, not mass] Arago— D th CO ’1; U234 Thm A (3;) (perceznt) 0:110:26 U ( ppm) Th (ppm) U238 U234. (appagreent) ratio 1413 250 ___________ 91.80 1.8 3.89: .81 0.50: .06 1.10:.06 0.56:.004 31,000:11,500 480 ___________ 94.94 2.8 4.71: .04 .34: .03 .99:.10 . 5:.10 30,500:11,000 845 ___________ 79.80 2.0 3.33: .03 1.12: .10 1.12:.04 .41:.004 57,000:11,500 143 500 ___________ 87.3 2.4 3.89:0.03 1.61:0.10 1.09:.01 0.39:.03 53,000: 5,000 685 ___________ 91.4 2.0 4.48:0.03 .39: .09 1.04:.19 .26:.01 31,000: 2,000 22 SEDIMENTS OF CENTRAL GULF OF MEXICO 0 _ O .. o ., 100 “ 100 100 m 200 200 200 “J . E 300 300 300 E: .2 400 400 400 Z w CORE CORE CORE : 500 1 1 1 500 97 500 96 ;. 600 _ 600 600 p. a 700 700 700 O 800 800 800 900 900 900 1000 1000 1000 20 40 60 PERCENT Ca 0 20 4O 60 PERCENT Ca 0 20 40 60 PERCENT l—#—+——l—i—I——{ Sr 0 2000 4000 6000 PPM Sr 0 2000 4000 6000 PPM Sr 0 2000 4000 6000 PPM Ca/Sr 50 100 500 Ca/Sr 50 100 500 Ca/Sr 50 100 500 o 100 200 ' U) ‘5? 300 ’— E ,: 400 Z 8 500 Z .- 600 E a. 700 LLI a 800 ~ 900 , 1000 so menu 40 so PERCENT 100° Ca o 20 40 so PERCENT Sr o 2000 woo sooo PPM woo sooorm Sr o 2000 woo sooo PPM Ca/Sr so, 100 500 Ca/Sr 50 100 500 Ca/Sr so 100 500 FIGURE 16.—Calcium, strontium, and calcium/strontium ratio in cores from north-south transect in the western gulf basin. Thus, the semiquantitative data used in this report have provided much information on the gross dis- tribution of trace and minor elements in marine sediments of the gulf. The lack of precise definition which is inherent in rapid analyses, however, pre- vents specific analyses of the species in which the elements occur. More detailed and sophisticated ana- lytical methods are necessary for these results. How- ever, the data presented herein provide a basis on which such studies may be founded. REFERENCES CITED Bender, M. L., 1971, Does upward diffusion supply the excess manganese in pelagic sediments?: Jour. Geophys. Re- search, v. 76, no. 18, p. 4212—4215. Bender, M. L., Ku, T. L., and Broecker, W. S., 1970, Accumu- lation rates of manganese in pelagic sediments and nodules: Earth and Planetary Sci. Letters v. 8, 143—148. Bischofl", J. L., and Sayles, F. L., 1972, Pore fluid and min- eralogical studies of recent marine sediments: Bauer depression region of East Pacific Rise: Jour. Sed. Pe- trology, v. 42, no. 3, p. 711—724. REFERENCES CITED 23 CORE 93 EXPLANATION a’. Foraminifera fl. Foraminifera hash - Silty clay Thin bedding 40 sorencem so PERCEN, Indggggtienéhin 5r 0 2000 won 6000??" 5' ° 20°“ ‘°°° “mp?" 1:: Thick bedding C3/5'50 10° 50° Ca/Sr 5° 10° 5°° / Burrowing 5? Mottled _.. Graded bedding 0 7 IL Convoluted bedding 100 h M Erosionai surface 200 __. Ca . 300 _ ..... Sr 032E 40° Cg? ...._... Ca/Sr 500 . 600 700 ‘ 300 V 960 40 so PERCENT A0 so PERCENT woo soooma 4000 soon ma Ca/Sr 50 100 500 Ca/Sr 50 100 500 FIGURE 16.—Continued. Bonatti, Enrico, Fisher, D. E., Joensuu, Oiva, and Rydell H. S., 1971, Post-depositional mobility of some transition ele- ments, phosphorous, uranium and thorium in deep sea sedi- ments: Gezochim. et Cosmochim. Acta, v. 35, p. 189—201. Bostrom, Kurt, 1967, The problem of excess manganese in pelagic sediments, in P. H. Abelson (6d,), Researches in geochemistry, v. 2: New York, John Wiley and Sons, Inc., p. 421—452. Bouma, A. H., Bryant, W. R., andDavies, D. K., 1971, TAMU results from the U.S.N.S. Kane 19.69-Expedition, Gulf of Mexico: Texas A&M, Dept. of Oceanography Rept. 71— 18—T, 139 p. ‘ Carroll, Dorothy, 1958, Role of clay minerals in the trans- portation of iron: Geochim. et Cosmochim. Acta, v. 14, nos. 1—2, p. 1—27. Chester, R., 1965, Elemental geochemistry of marine sedi- ments in Riley, J. P., and Skirrow, G. (eds), Chemical Oceanography, v. 2: New York, Academic Press. Chester, R., and Hughes, M. J., 1967, A chemical technique for the separation of ferro-manganese minerals, car- bonate minerals, and adsorbed trace elements from pelagic sediments: Chem. Geology, v. 2, p. 249—262. ' Cohen, A. 0., Jr., 1959, Simplified estimators for normal distribution when samples are singly censored or trun- cated: Technometrics, v. 1, no. 3, p. 217—237. Davies, D. K., 1968, Carbonate turbidites, Gulf of Mexico; Jour. of Sed. Petrology, V. 32$, p. 1100—1109. Ferrell, R. E., Flanagan, P. A., and Devine, S. B., 1971, Com- parative mineralogy of recent and Pleistocene sediments from the deep Gulf of Mexico; part D in Morgan, J. P., and Ferrell, R. E., Quaternary geology of the Louisiana continental shelf, U.S.G.S. Tech. Rept. No. 3: Baton Rouge, La., Louisiana State Univ. Garrels, R. M., 1960, Mineral equilibria at low temperature and pressure: New York, Harper and Brothers, 254 p. 24 Garrison, L. E., and Martin, R. G., Jr., 1973, Geologic struc- tures in the Gulf of Mexico basin, U.S. Geol. Survey Prof. Paper 773, 85 p. Grimes, D. J., and Marranzino, A. P., 1968, Direct-current arc and alternating-current spark emission spectrographic field methods for semiquantitative analysis of geologic materials: U.S. Geol. Survey Circ. 591, 6 p. Hirst, D. M., 1962, The geochemistry of modern sediments from the Gulf of Paria—Part II, the location and distri- bution of trace elements: Geochim. et Co‘smochim. Acta, v. 26, p. 1147—1187. Holmes, C. W., 1965, Rates of sedimentation in the Drake Passage: Ph.D. Thesis, Florida State University, 100 p. 1973, Distribution of selected elements in surficial marine sediments of the northern Gulf of Mexico, con- tinental shelf and slope: U.S. Geol. Survey Prof. Paper 814, 7 p. Horn, M. K., and Adams, J. A. S., 1966, Computer-derived geochemical balances and element abundances: Geochim. et Cosmochim. Acta, v. 30, p. 279—297. Huang, T. C., 1969, The sediment and sedimentary processes of the eastern Mississippi Cone, Gulf of Mexico: Ph.D. thesis, Florida State University, 124 p. Imbrie, John, 1963, Factor and vector analysis programs for analyzing geologic data—U.S. Oflice of Naval Research, Geography Br., Contract Nonr. 1228(26), Tech. Tect. Rept. 6: Evanston, Ill., Northwestern Univ., 83 p. Jenne, E. A., 1968, Controls on Mn, Fe, Co, Ni, Cu, and Zn concentrations in soils and waters—The significant role of hydrous Mn and Fe oxides in Trace inorganics in water—Am. Chem. Soc, 153d ann. mtg., Miami Beach, Fla., 1967, Div. Water, Air, and Waste Chemistry Sym- posium: Washington, D. C., Am. Chem. Soc. (Adv. Chem- istry Ser. 73), p. 337—387. Kennett, J. P., and Huddleston, Paul, 1972, Late Pleistocene paleoclimatology foraminiferal biostratigraphy and te- phrochronology, western Gulf of Mexico: Quaternary Res, v. 2, p. 38—69. Krauskopf, K. B., 1956, Factors controlling the concentrations of thirteen rare metals in sea water: Geochim. et Cos- mochim. Acta, v. 9, nos. 1—2, p. 1—32. l l SEDIMENTS OF CENTRAL GULF OF MEXICO 1957, Separation of manganese from iron in sedi- mentary processes: Geochem. et Cosmochim. Acta, v. 12, p. 61—84. 1967, Introduction to geochemistry; New York, Mc- Graw-Hill Book Co., 721 p. Krumbein, W. C., and Graybill, F. A., 1965, An introduction to statistical models in geology: New York, McGraw-Hill Book Co., 475 p. Ludwig, C. P., 1971, The micropaleontological boundary be- tween the Holocene and Pleistocene sediments: M. S. thesis, Texas A&M University, 143 p. Lynn, D. C., and Bonatti, Enrico, 1965, Mobility of manga- nese in diagenesis of deep sea sediments: Marine Geology, v. 3, p. 457—474. Miesch, A. T., 1967, Method of computation for estimating geochemical abundance: U.S. Geol. Survey Prof. Paper 574—B, 15 p. Newman, J. W., Parker, P. L., and Behrens, E. W., 1973. Organic carbon isotope ratios in Quaternary cores from the Gulf of Mexico: Geochim. et Cosmochim. Acta (in press). Rankama, Kalervo, and Sahama, Chicago Univ. Press, 912 p. Shacklette, H. T., Hamilton, J. C., Boerngen, J. G., and Bowles, J. M., 1971, Elemental composition of surficial materials in the conterminous United States: U.S. Geol. Survey Prof. Paper 574—D, 71 p. Sichel, H. S., 1952, New methods in the statistical evaluation of mine sampling data: Inst. Mining and Metallurgy Trans, v. 61, p. 261—288. Turekian, K. K., 1964, The marine geochemistry of strontium: Geochim. et Cosmochim. Acta, v. 28, p. 1479—4496. Uchupi, Elazar, and Emery, K. 0., 1968, Structure of con- tinental margin oflp ‘Gulf Coast of United States: Am. Assoc. Petroleum Geologists Bull., v. 52, no. 7, p. 1162— 1193. Walker, J. R., and Massingill, J. V., 1970, Slump features on the Mississippi fan, northeast Gulf of Mexico, Geological Soc. Amer. Bull., v. 81, no. 10, p. 3101—3108. Th. G., 1950, Geochemistry: UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY 30° 20° 18° 16° 30° 28° 26° 24° 22° 20° 18° 16° 30° 16° 30° 28° 26° 24° 22° 20° 18° 16° 96° 94° 92° 90° I _ UNITED STATES UNITED STATES 124 .120 .118 .146 .129 I I .60 .57 .84 83 .4 .8 O 4 43 .127 .1413 138, 13'9 PENINSULA a .136 y CONTOURINTERVALzmIMETRES —18 0 100 200 300 400 500 KI LO M ETR ES 3 I I I J II II I I I 0 100 200 300 MILES I I | I I I I 19 88 86 I 94° 92° 90° 84° 82° 80° SAMPLE LOCATIONS 82' 80° T 899°9994R8918 A 22° YUCATAN w PENINSULA 4 20° >_ 5 g E 10 fl 3 ‘5 15 a 18° on: o 100 200 300 400 500 KILOMETRES II E If 20 I I I I I I I I | “- 25I I II II I I 3M 0 100 200 300 MILES I I I I I I I I lg 96° 94° 92° 90° 88° 86° 84° 82° 80° 96° 94 92 9o 88 86 84 82 80 UNITED STATES 8‘8‘ 9‘ 98 648} E150 35000 PARTS PER MILLION ”@9998: Q! m 100 200 300 400 500 KILOMETRES I I I I I 200 300 MILES % YUCATAN 52 PENINSULA a x ® 41 >. 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I I we _ UNITED STATES _ 30. 28° — A 28° 26° 5“ 26. 24° 1 200 M500 8.1. PARTS PER MILLION I50Q i 2000 \Q a} 4; . YUCATAN PENINSULA 22° — 20° —‘ *6 0 5F 0 z 2 18° ~ W 15 L5 3 20 05 o 100 200 300 400 500 KILOMETRES g E 0. LI II I I | I I 25 In I I I I I I I 30 o 100 200 300 MILES m° I I I I I I I I 98° 96° 94° 92° 90° 88° 86° 84° _ 240 I 22° a 20° I 18. 16° STRONTIUM CIRCULAR HISTOGRAMS OF structed 80° 26° 30° 28° 26° 24° 22° 20° 18° 16° 30° 28° 26° 24° 22° 20° 18° 16° 30° 28° 26° 24° 22° 20° 18° 16° ELEMENTAL CONCENTRATIONS VERSUS FREQUENCY PERCENT IN THE SEDIMENTS OF THE CENTRAL GULF OF MEXICO NOTE: The rose in the right corner of each map is the total distribution of all samples. number in the center of each rose represents the number of samples on Which rose was con— PROFESSIONAL PAPER 928 PLATE 1 80° UNITED STATES @ 8‘ 9599981 8 9 PENINSULA fii§°°°a 500 KILOMETRES FREQUENCY PERCENT N N ._. H 01 O m 0 (J1 26° CHROMIUM 16° 80° 80° UNITED STATES PENINSULA 500 KILOMETRES FREQUENCY PERCENT ‘4 30‘ L 28» 26° L 18" MAGNESIUM 16° 80° 80° _ UNITED STATES {5’ 89.9. 9 IRS‘ 8%? 0° 88 <5 (:1 \N PENINSULA (3:59 @ U1 FREQUENCY PERCENT 500 KILOM ETRES WEE—HP—H ‘ 30° .2 28° 26° — 24° — 22° fl 20° a 18° 16° 80° Interior—Geological Survey, Reston, Virgini371975~G75130 TITANIUM “‘(I A a: ERTS-l A NEW WIN DOW ON OUR PLANET GEOLOGICAL SURVEY PROFESSIONAL; PAPER 929 e ERTS-I ' A NEW WINDOW ONOUR: PLANET * RICHARD S. WILLIAMS, IR, and WILLIAM D. CARTER, EDITORS GEOLOGICAL SURVEY PROFESSIONAL PAPER 929 I . Cooperating Organizations: I I US Department of the Interidr: Geological Survey I Bureau of Land Management Bureau of Reclamation Bureau of Mines I Fish and Wildlife Service I National Park Service University of Tennessee I Environmental Research lnstituIIe of Michigan US Army Corps of Engineers 3 The American University I let Propulsion Laboratory (California Institute of Technology) University of Minnesota I I National Oceanic and Atmospheric Administration University of Alabama California State University ”My “BRA Wyoming Geological Survey my" 0F gum/9M A Cover photography of the Earth taken from Apollo (72—HC—928) courtesy of National Aeronautics and Space Administration UNITED STATES GOVERIIIMENT PRINTING OFFICE, WASHINGTON ': |976 — UNITED STATES DEPARTMENT OF THE INTERIOR THOMAS S. KLEPPE, SECRETARY GEOLOGICAL SURVEY V. E. MCKELVEY, DIRECTOR For sale by the Superintendent of Documents, US. Government Printing Office Washington, DC. 20402—3513 (paper cover) Stock Number 024—001—02757—7 Catalog Number I 19.162929 Library of Congress catalog-card No. 75—37451 FOREWORD he launch, on July 23, 1972, of the first Earth Resources Technology T Satellite .(ERTS—1) by the National Aeronautics and Space Administration environment. The ERTS spacecraft represent the first step in merging space and remote-sensing technologies into a system for inventorying and managing the Earth’s resources. This development is a good example of applying the periments ever undertaken. Examples presented in this book demonstrate ERTS’ vast potential for inventorying resources, monitoring environmental conditions, and measur- More than being merely another scientific experiment, this undertaking is a multinational, multidisciplinary experiment on a global scale. Approxi- mately 100 nations are participating, and it is believed that the program will contribute materially to achievement of an objective basis for setting inter- related resource, environmental, and social priorities for much of the world. Data from US. Earth resources survey satellites are of help to all nations existence. The Government of the United States hopes and believes that by work- ing together with other nations we will be able to develop cooperative pro- grams in remote sensing. The development of these programs will allow the diffusion of knowledge gained from remote sensor technology, such as ERTS, by making data available and providing for the education and training of technicians in this field, and also through the user assistance necessary to convert imagery, photographs, and other data into useful information for resource inventory and survey purposes. Typical repetitive information al- ready available relates to such disciplines as geology, hydrology, geography, cartography, agriculture and rangeland management, forestry, and land use mapping and planning. Original electronic signals of data acquired with ERTS are being con- verted by NASA to photographic—type images, that in turn are being pro- cessed at the EROS Data Center, Sioux Falls, South Dakota. The Center, thus, is a key installation serving as an international repository for processing, interpreting, and disseminating thousands of images per year of a wide variety of land and water features of the world. These images are being pro- vided to all users, domestic and foreign, at nominal cost. The data are par- ticularly useful for those who are involved in urban and suburban planning, zoning, construction, and similar activities, as they provide unique tools in helping to arrive at wise land- and water-use decisions. A number of formal scientific experiments have been completed or are in progress within the Department of the Interior that have demonstrated contributions from space technology to resource assessments. Ten bureaus of the Department have roles in the ERTS project: the Bureaus of Indian Affairs, Land Management, Mines, Outdoor Recreation, and Reclamation and the Fish and Wildlife Service, the Bonneville Power Administration, the National Park Service, Office of Trust Territories, and the Geological Survey. Nearly all of these participating bureaus are represented in the many papers included in this book. I encourage you, whether you be a scientist, resource manager, educator, or layman from the United States or from an- other country, to review these examples of this exciting and totally new technology which has been developed for the benefit of all the world’s peoples. I think that you will agree with me that we have made a fine start in the effective and beneficial use of ”space” for all mankind. V. E. McKelvey, Director, US. Geological Survey iscovery, or the possibility of it, is that which D whets, stimulates, and hopefully satisfies the cravings of scientists, inventors, and explorers. The hope of discovery pushed Ericson and Columbus west across the Atlantic against the odds that their frail crafts would perish by storm or “fall off the edge of the Earth.” The desire for discovery encouraged Lewis and Clark, Powell, Hayden, and others to ex- plore our western plains, mountains, river canyons, and mineral and water resources against the many odds of traversing unknown areas. Lt. Maury, working against tradition and inertia in the US Navy, labori- ously compiled the many bits of wind, current, and sea-state information contained in the logs of sailing ship captains to chart the ocean currents and winds. Such audacious, and to some, revolutionary, discov- eries also inspired man to learn to fly and eventually project himself into space. At this time, man has already landed on and begun exploration of the Moon. During the progress of the Mercury, Gemini, and Apollo programs, our astro- nauts began to carry cameras and took many photo- graphs of the Earth from space. These photographs immediately interested earth-bound scientists in- volved in important projects of mapping the geology, hydrology, agriculture, and other environmental phe- nomena of the Earth. The NASA Earth Resources Survey Program was born in 1964 as a handful of scientists representing a few scientific disciplines from major US. Government agencies. The program gradually grew to include sci- entists from all earth-resource disciplines in industry, university, and state organizations. Through coopera- tive information exchange and training, scientists from all over the world became interested and involved. These scientists studied various types of remotely sensed data from aircraft and spacecraft to develop PREFACE specifications for an Earth Resources Technology Satellite (ERTS—1). Six hundred proposals were sub- mitted to NASA to analyze ERTS—1 data. More than 320 experiments, representing multidisciplinary and multinational interests, were selected to give the first satellite as broad a test as possible. Of the 81 experi- ments submitted to NASA by scientists of the various bureaus within the US. Department of the Interior, 45 were ultimately selected and made. in our capacity as research scientists within the EROS Program, it was our responsibility to not only carry out our own ERTS investigations in lceland and South America, respectively, but to coordinate, re- view, and document, for the US Geological Survey and NASA, the US. Department of the Interior results of the ERTS experiment. As experimental findings flowed through our hands from lnterior scientists to NASA, it became increasingly clear that these results would be of interest to earth scientists throughout the world, especially those in developing nations, who are just beginning to explore potential applications of satellite data. While the results presented herein are but a small sampling of the work currently in progress around the world, we believe that they are representative of the capabilities that are fast becoming available to earth scientists and resource managers, not only in the US. Department of the Interior but in other domestic and oreign organizations as well. We hope that this pub- as well. Slide set E—1—30—35 may be purchased from the EROS Data Center, Sioux Falls, South Dakota V 57198. We also hope that the book will help national decisionmakers, as well as taxpayers, realize the value of expenditures, past and future, that are made for programs such as ERTS. In nearly every respect ERTS—1 is an exceptional and unique satellite and may very well represent the most important accomplishment yet of our space pro- gram in terms of benefits to our Nation, to other na- tions, and hence to all people of the world. ERTS, like its equally inexpensive sister satellites, the civilian weather satellites (NCAA and Nimbus), was designed so that its data would serve a large number of users within the United States and throughout the world. For the first time in the history of the U.S. space pro— gram, with the exception of some civilian meteoro- logical-satellite data, data acquired from an unman- ned orbiting spacecraft are being made available to all, inexpensively, and on an unrestricted basis. The source of information for this national and interna- tional distribution is the EROS Data Center in Sioux Falls, South Dakota. As you review the examples of the applications of ERTS imagery in this book and the excellent collection of ERTS images in the NASA Special Publication com- piled by Short, Lowman, Freden, and Finch, Mission to Earth: Landsat Views the World,* it is hard to be- lieve that only 100 years ago man’s view of his world was generally limited to what he could see from a sailing vessel, from horseback, or afoot. Because of ERTS, anyone can now sit down at a microfilm projec- tion console and view nearly all the land areas of the world; one can even order specific images from the EROS Data Center for more comprehensive analysis. For the first time in history the entire world is at . everyone’s fingertips; for many parts of the world, in particular North America (because of complete cover- age afforded by several ERTS receiving stations in the United States and Canada), the changing face of our planet, whether the changes are caused by natural forces or by man’s often disruptive forces, is avail- able for analysis on an 18-day cycle. The availability of ERTS data could not have come at a more propitious time for both the advanced and the developing countries of the world because of the pressure to manage natural resources and be- cause of man’s capacity to modify the face of the planet. To monitor dynamic phenomena (natural vegetation, crops, glaciers, snow cover), to monitor some of man’s environmental impact (strip mining, * Short, N. M., Lowman, P. D., Freden, S. C., and Finch, W. A., 1376, MIssron to Earth: Landsat Views the World: NASA SP— 360 (in press). Vl ———" reservoirs, irrigation, pollution), and to help other countries wisely develop their natural resources, the continuous acquisition of ERTS imagery has become a necessity. Four countries, Brazil, Canada, Italy, and the United States, have ERTS receiving stations in op— eration. Four additional ERTS receiving stations, in Canada, Chile, Iran, and Zaire, have been designed, but construction is not yet complete. Australia, India, Japan, Norway, and Upper Volta are all seriously con- sidering building receiving stations. The United States has pioneered in the creation of a technology which offers us and other nations a method by which all may more wisely use their natural resources. Our small planet has limited sup- plies of resources which we must learn to manage and conserve for future generations. Through careful ob- servation and planning this can be done—if tools such as ERTS and those designed for future satellites are developed and used to the maximum benefit of all mankind. ERTS—1 then truly is a new window on our planet. Our challenge now is to use this new knowledge in an effective way and to integrate such information into more traditional information sys- tems. We should also like to mention the foresight of Dr. William T. Pecora, Director, U. S. Geological Sur- vey, 1965—71, and Undersecretary of the Interior, 1971—72. As first Director of the Earth Resources Observation Systems Program of the Department of the Interior (1966—72) he firmly believed that “by going to space we can learn more about the Earth.” His scientific integrity and jovial enthusiasm inspired us all to work toward the success of the Earth Re- sources Technology Satellite (ERTS—1). Unfortunately, he died on July 19, 1972, 4 days prior to the launch of ERTS-1, and consequently never saw the realiza- tion of this long-sought goal. We think that he would have been pleased that the results contained in this book confirmed his forecast manyfold. We wish to take this opportunity to acknowledge the response and efforts of the contributing authors. We also wish to acknowledge the efforts of Mary Ann Milosavich who coordinated the assembly of the book and typed its text; Susan Moorlag who coordinated the graphic materials; the many people of the U.S. Geological Survey who edited the text and prepared the final illustrations; and Priscilla Woll, who re- viewed and proofread the manuscript as well as pro- vided guidance in formation of the book. Richard S. Williams, Jr. William D. Carter ERTS-1, A NEW WINDOW ON OUR PLANET 1 Foreword, by V. E. McKelvey ___________________________________ Ill Preface, by Richard S. Williams, Jr., and William D. Carter, editors __ V Conversion table and list of symbols and abbreviations ____________ XIX Introduction, by John M. DeNoyer, US. Geological Survey __________ 1 ERTS—1 MSS false—color composites, by Charles F. Withington, US Geological Survey ___________________________________ 3 FIGURE 1. Color composite ERTS—1 image of the upper Chesapeake Bay area __ 4 2. ERTS—1 image of the upper Chesapeake Bay area, band 4 ________ 5 3. ERTS—1 image of the upper Chesapeake Bay area, band 5 ________ 5 4. ERTS—1 image of the upper Chesapeake Bay area, band 6 ________ 5 5. ERTS—1 image of the upper Chesapeake Bay area, band 7 ________ 5 6. The electromagnetic spectrum and ERTS—1 sensor relationships ___ 6 Chapter 1. Applications to Cartography Introduction, by Alden P. Colvocoresses, US. Geological Survey ___- 12 FIGURE 7. Color composite ERTS—1 image of the Denver, Colorado, area in winter ___________________________________________________ 14 8. Color composite ERTS—1 image of the Denver, Colorado, area in summer _________________________________________________ 15 9. Space Oblique Mercator projection ____________________________ 17 10. ERTS images of southeastern Pennsylvania, showing the thin-cloud penetration capability of band 7 as compared to band 5 _______ 18 11. Comparison of maps and ERTS—1 image of Lake Balkash, U.S.S.R. __ 19 12. Thematic extraction of open water, upper Chesapeake Bay area __ 20 13. Thematic extraction of infrared-reflective vegetation, upper Chesa- peake Bay area ___________________________________________ 20 14. Space imagery applied to aeronautical charting, Jebel Uweinat area, Libya, Sudan, and United Arab Republic 21 15. Comparison of nautical chart and ERTS image—oFC—dll—ier—B_a_y_,-Aust_ral_ia 22 ERTS nominal scenes, by James W. Schoonmaker, Jr., and Robert B. McEwen, US. Geological Survey __________________________ 23 FIGURE 16. Bisector format of ERTS images at 45° lat ______________________ 24 17. ERTS nominal scenes of Florida _______________________________ 24 18. Gridded color composite ERTS—1 image of the upper Chesapeake Bay ____________________________________________________ 25 Orthoimage mosaic of New Jersey, by Winston Sibert and Fitzhugh T. Clark, US. Geological Survey _____________________________ 26 FIGURE 19. Color composite ERTS—1 orthoimage mosaic of New Jersey _______ 27 1 Satellite image maps of the State of Arizona and of Phoenix, by Joseph 3 T. Pilonero, US. Geological Survey _______________________ 29 FIGURE 20. ERTS—1 image map of Arizona ________________________________ 30 21. ERTS—1 image map of Phoenix, Arizona ________________________ 31 VII Digital color mosaic of parts of Wyoming and Montana, by Grover Tor- bert, Bureau of Land Management, and C. J. Robinove, U.S. Geological Survey ______________________________________ FIGURE 22. Computer-processed color composite ERTS-1 mosaic of parts of Wyoming and Montana ___________________________________ Geodetic control in polar regions for accurate mapping with ERTS imagery, by William R. MacDonald, U.S. Geological Survey ____ FIGURE 23. Image and map of the McMurdo Sound region, Antarctica ______ Antarctic cartography, by William R. MacDonald, U.S. Geological Sur- vey ___________________________________________________ FIGURE 24. Topographic maps and ERTS-1 image mosaic of Drygalski Ice Tongue, Victoria Land coast area __________________________ 25. Topographic maps and ERTS—1 image mosaic of Cape Adare, Vic- toria Land coast area ____________________________________ 26. Sketch map and ERTS—1 image mosaic of Thwaites Iceberg Tongue, Antarctica _______________________________________________ 27. Map of McMurdo Sound region compared with ERTS—1 image mosaic __________________________________________________ 28. Australian map of the Lambert Glacier area of Antarctica compared with an ERTS—1 image mosaic _____________________________ Cadastral boundaries on ERTS-1 images, by Grover Torbert, Bureau of Land Management, and William R. Hemphill, U.S. Geological Survey ________________________________________________ FIGURE 29. Color composite ERTS——1 image of the Sheridan, Wyoming, area __ 30. Computer-processed combination of part of the Sheridan ERTS—1 image and cadastral survey delineation of township, range, and section boundaries _______________________________________ 31. Standard U.S. Geological Survey map of the Sheridan area of Wyo- ming ___________________________________________________ References ___________________________________________________ Chapter 2. Applications to Geology and Geophysics Introduction, by William A. Fischer, U.S. Geological Survey _________ Geologic analysis of the Santa Lucia Range, California, by Donald C. Ross, U.S. Geological Survey _____________________________ FIGURE 32. Color composite ERTS—1 image of the Salinas Valley and Santa Lucia Range, California __________________________________ 33. ERTS—1 image showing interpretation of photolineaments in the northern Santa Lucia Range, California _____________________ An interpretation of the Jordan Rift Valley, by G. F. Brown and A. C. Huffman, U.S. Geological Survey ____________________________ FIGURE 34. Map of the Red Sea area showing location of tectonic-plate ro- tation poles ___________________________________________ 35. Color composite ERTS—1 image mosaic of the Jordan Rift Valley- Geological structure in the western Brooks Range area, by Ernest H. Lathram, U.S. Geological Survey _____________________________ FIGURE 36. Color Icomposite ERTS—1 image of the western Brooks Range area, A as a __________________________________________________ 37. Annotated ERTS—1 image of the western Brooks Range area, Alaska, showing geologic features and place names ___________ VIII 32 33 34 34 37 38 39 40 41 42 44 45 46 46 47 48 50 51 52 53 54 55 56 57 58 t Geological evaluation of north-central Arizona, by Donald P. Elston, US. Geological Survey __________________________________ 59 FIGURE 38. Color composite ERTS—1 image of north-central Arizona ______ 60 39. Computer processed four-band color composite ERTS—1 image of north-central Arizona _____________________________________ 61_ 40. Geologic map of north-central Arizona ________________________ 62 41. Geologic map of north-central Arizona compiled on an ERTS—1 image base ______________________________________________ 65 42. Fault and lineament map of north-central Arizona compiled on an ERTS—1 image base _______________________________________ 66 Glacial geology and soils in the Midwestern United States, by Roger B. Morrison, US. Geological Survey _______________________ 67 FIGURE 43. Color composite ERTS—1 image of part of Iowa, west of Des Moines _________________________________________________ 68 44. ERTS—1 image, band 7, with interpretation of soil types _________ 70 45. Mosaic of ERTS—1 images, band 7, of west-central Illinois with interpretation of soil types ________________________________ 71 Enhancement of topographic features by snow cover, by Roger B. Mor- rison, US Geological Survey _____________________________ 72 FIGURE 46. Color composite ERTS—1 image of western Nebraska showing snow-enhanced topographic details _______________________ 73 47. Geologic terrane map compiled on ERTS—1 image, band 5 ______ 74 48. ERTS—1 image of western Nebraska in summer showing relative lack of topographic detail _________________________________ 75 Hydrogeology of closed basins and deserts of South America, by George E. Stoertz and William D. Carter, US. Geological Survey 76 FIGURE 49. Color composite ERTS—1 image of the Salar de Coipasa region of Bolivia and Chile ____________________________________ 78 50. Geologic and hydrologic interpretation and explanations of fea- tures identified in the Salar de Coipasa region _________________ 79 51. Index map of salar revisions _________________________________ 80 52. Example of outlines of several salars revised by ERTS data _______ 80 Sand seas of the world, by Edwin D. McKee and Carol S. Breed, U.S. Geological Survey _______________________________________ 81 FIGURE 53. Index map of the sand seas of Africa, Asia, Australia, and North America _________________________________________________ 82 54. Color composite ERTS—1 image mosaic of the southwest United States desert and the Gran Desierto de Sonora in Mexico _____ 83 55. Color composite ERTS—1 image showing parallel-straight or linear dunes in the Kalahari Desert, of South Africa _________________ 84 56. Color composite ERTS—1 image showing parallel-wavy or crescentic dunes (a megabarchan desert) in Saudi Arabia ________________ 85 57. Color composite ERTS—1 image showing star or radial megadunes in Algeria _______________________________________________ 86 58. Color composite ERTS—1 image showing parabolic dunes in the Rajasthan Desert of India _____________________________ 87 59. Color composite ERTS—1 image showing flat sheets and stringer dunes in South-West Africa _______________________________ 88 Detection of hydrothermal sulfide deposits, Saindak area, western Pakistan, by Robert G. Schmidt, US. Geological Survey _______ 89 FIGURE 60. Digitally enhanced false-color composite ERTS—1 image of the Saindak area of western Pakistan __________________________ 90 61. Annotated ERTS—1 'mage showing location of significant geologic features of the Saindak area of Pakistan _____________________ 91 Structural geology and mineral-resources inventory of the Andes Moun- tains, South America, by William D. Carter, US. Geological Survey ________________________________________________ 92 FIGURE 62. ERTS—1 image mosaic of the La Paz area, Bolivia, Peru, and Chile 94 63. Image linear map of the La Paz area __________________________ 96 64. Relative confidence map of the La Paz area ____________________ 97 65. Metallogenic map of the La Paz area __________________________ 98 66. Seismic-hazard map of the La Paz area _______________________ 98 IX Clues to geologic structure possibly indicating oil and gas sources, by Ernest H. Lathram, U.S. Geological Survey __________________ FIGURE 67. Color composite ERTS—1 image of foothills and coastal plains near Umiat, Alaska _____________________________________ 68. ERTS—1 image of the Umiat area, Alaska, showing structural fea- tures and lineation of lakes _______________________________ Discrimination of rock types and detection of hydrothermally altered areas in south-central Nevada, by Lawrence C. Rowan and Pamela H. Wetlaufer, U.S. Geological Survey, and A. F. H. Goetz, Jet Propulsion Laboratory __________________________ FIGURE 69. Stretched-ratio color composite ERTS—1 image of south-central Nevada made from computer compatible tapes ____________ 70. Color composite ERTS—1 image of the. south-central Nevada area made from computer compatible tapes ____________________ 71. Conventional color composite ERTS-1 image of the entire south— central Nevada area ______________________________________ New method for monitoring global volcanic activity, by Peter L. Ward and Jerry P. Eaton, U.S. Geological Survey __________________ FIGURE 72. Map showing instrument sites of the prototype volcano-surveillance system _________________________________________________ 73. Data collection platform, Mount Baker, Washington ____________ 74. Graph of seismic activity recorded by a data collection platform at Volcan Fuego, Guatemala _______________________________ Dynamic environmental phenomena in southwestern Iceland, by Rich- ard S. Williams, Jr., U.S. Geological Survey _________________ FIGURE 75. Color composite ERTS—1 image mosaic of west-central and southwestern Iceland ____________________________________ 76. Map of part of west-central and southwestern Iceland ___________ Active faults in the Los Angeles—Ventura area of southern California, by Russell H. Campbell, U.S. Geological Survey ________________ FIGURE 77. Color composite ERTS—1 image of the greater Los Angeles area 0 southern California especially made to enhance geologic features _________________________________________________ 78. Annotated ERTS—1 image of the greater Los Angeles area, of south— ern California showing location of maior and minor faults _____ Environmental geology of the central Gulf of Alaska coast, by Austin Post, U.S. Geological Survey ______________________________ FIGURE 79. Color composite ERTS—1 image of the central Gulf of Alaska coast __________________________________________________ Debris avalanches at Mount Baker Volcano, Washington, by David Frank, U.S. Geological Survey ____________________________ FIGURE 80. Color composite ERTS—1 image of the Mount Baker area, Wash- ington _____________________ 81. Enlargement of a part of the Mount Baker image, showing the area of debris avalanches . Structural features related to earthquakes in Managua, Nicaragua, and Cordoba, Mexico, by William D. Carter, U.S. Geological Survey, and Jack N. Rinker, U.S. Army Corps of Engineers ___________ FIGURE 82. Color composite ERTS—1 image of the Managua area, Nicaragua- 83. Map of earthquake area, Nicaragua, plotted on ERTS-1 image ___ References ___________________________________________________ X 99 100 101 102 103 104 105 106 107 108 108 109 110 112 113 114 115 117 118 120 121 122 123 124 125 126 i Chapter 3. Applications to Water Resources Introduction, by Morris Deutsch, US. Geological Survey ____________ 12-9 Water resources in the Delaware River basin, by Richard W. Paulson, US. Geological Survey __________________________________ 132 FIGURE 84. Data collection platform sites, Delaware River basin, plotted on ERTS—1 image mosaic ____________________________________ 133 Hydrology of the Wind River basin and adjacent areas of Wyoming, by Lynn M. Shown and J. Robert Owen, US Geological Survey __ 134 FIGURE 85. Color composite ERTS—1 image of the Wind River basin and adja- cent areas, Wyoming ___________________________________ 135 Improving estimates of streamflow characteristics, by Este F. Hollyday ”x and Edward J. Pluhowski, US. Geological Survey ____________ 136 FIGURE 86. Color composite ERTS—1 image of the Delmarva Peninsula area“ 137 87. Flow diagram of technique for improving estimates of stream- flow characteristics ______________________________________ 138 Monitoring water resources in Qom Playa, west-central Iran, by Daniel ’ B. Krinsley, US. Geological Survey ________________________ 139 FIGURE 88. Color composite ERTS—1 image of the Qom Playa area of west- central Iran on Sept. 22, 1972 _____________________________ 140 89. Color composite ERTS—1 image of the Qom Playa area of west- central Iran on May 14, 1973 ______________________________ 141 90. Comparison of the climatic data from Qom with the lake area and volume at Qom Playa, from Sept. 4, 1972, to May 14, 1973__ 142 Lake fluctuations in the Shiraz and Neriz Playas of Iran, by Daniel B. Krinsley, U.S. Geological Survey __________________________ 143 FIGURE 91. Color composite ERTS—1 image of the Shiraz and Neriz Playas, Iran, on Sept. 20, 1972 __________________________________ 144 92. Color composite ERTS—1 image of the Shiraz and Neriz Playas, Iran, on Mar. 1, 1973 ___________________________________ 146 93. Color composite ERTS—1 image of the Shiraz and Neriz Playas, Iran, on Aug. 28, 1973 ________________________________________ 147 94. Diagram showing lake fluctuations at Shiraz and Neriz Playas, 1972—73 ________________________________________________ 148 95. A comparison of the climatic data from Neriz with the lake areas and volumes at Shiraz and Neriz Playas, for the period Sept. 2, 1972, to Aug. 28, 1973 _________________________________ 149 Ecological model in Florida, by Aaron L. Higer, A. Eugene Coker, and Edwin H. Cordes, US. Geological Survey ___________________ 150 FIGURE 96. Color composite ERTS—1 image mosaic of the State of Florida ___ 151 97. Wildlife ecological model, Shark River Slough, Florida ___________ 152 98. Data collection platform, Everglades National Park, south Florida __ 152 99. Surface~water storage model, Shark River Slough, Florida ________ 152 100. Wood storks nesting _______________________________________ 152 Turbidity in Lake Superior, by Michael Sydor, University of Minnesota- 153 FIGURE 101. Correlation of intensity from band 5 of ERTS—1 image with tur- bidity __________________________________________________ 153 l 102. Density-sliced image using color to show turbidity ___________ 153 103. Harbor and lake image density levels identified by corresponding turbidity levels on ERTS—1 image ___________________________ 154 104. Computer printout of image-density levels from computer com- . patible tapes ____________________________________________ 154 105. Index of map of Lake Superior study area ______________________ 154 106. Part of ERTS—1 image showing the Lake Superior study area ______ 155 107. Graph showing variation in M55 band signals __________________ 155 XI —————" Dynamics of suspended-sediment plumes, by Edward ]. Pluhowski, U.S. Geological Survey ______________________________________ 157 FlGURE 108. Color composite ERTS—1 image of the Lake Ontario-Niagara River area, on Sept. 3, 1973 ______________________________ 156 109. Part of an ERTS—1 image showing sediment plumes in Lake Ontario on Apr. 12, 1973 _________________________________________ 157 110. Part of an ERTS—1 image showing sediment plumes in Lake Ontario on Apr. 29, 1973 _________________________________________ 157 111. Part of an ERTS—1 image made on Sept. 3, 1973, enlarged and color enhanced by Stanford University’s ESIAC console, showing the Niagara River plume ______________________________________ 158 Water-management model of the Florida Everglades, by Aaron L. Higer, Edwin H. Cordes, and A. Eugene Coker, U.S. Geological Survey- 159 FIGURE112. Color composite ERTS—1 image of the Everglades National Park area of Florida __________________________________________ 160 113. Annotated ERTS—1 image showing water-management conservation areas in the Everglades National Park area of Florida _________ 161 114. Determination of surface—water storage in Conservation Area No. 1 161 115. Electronically processed part of ERTS—1 image of Conservation Area No. 1 _____________________________________________ 161 Suspended sediment in Great Slave Lake, Northwest Territories, Canada, by Donald R. Wiesnet, National Oceanic and Atmos- pheric Administration ___________________________________ 167- FIGURE116. Color composite ERTS—1 image of the Great Slave Lake area, Northwest Territories, Canada _____________________________ 163 Discovery and significance of the Beech Grove lineament of Tennessee, by G. K. Moore and Este F. Hollyday, U.S. Geological Survey __ 164 FIGURE 117. Color composite ERTS—1 image of central Tennessee on Oct. 17, 1972, showing location of the Beech Grove lineament _________ 165 118. Index map showing the location of the Beech Grove lineament __ 166 119. Color composite ERTS—1 image of central Tennessee on Dec. 28, 1972 ____________________________________________________ 167 Western Lake Superior ice, by Michael Sydor, University of Minnesota- 169 FlGURE120. Color composite ERTS—1 image of western Lake Superior show— ing typical ice pack ______________________________________ 170 121. Density-sliced ERTS~1 image using color to identify areas of intense ice packing ______________________________________________ 171 122. Graph showing albedo, western Lake Superior __________________ 171 I123. Graph showing ice growth, Duluth—Superior harbor _____________ 172 124. Graph showing estimate of volume of ice cover that is highly packed, western Lake Superior ___________________________ 172 Measuring snow-covered area to predict reservoir inflow, by Robert M. Krimmel and Mark F. Meier, U.S. Geological Survey ______ 173 FIGURE 125 Color composite ERTS-1 image mosaic of the Puget Sound re- gion, Washington ________________________________________ 174 126. index map of Cascade Mountains drainage basins ______________ 174 127. Graph showing percentage of drainage basin area covered by snow 175 Mapping snow extent in the Sierra Nevada of California, by Donald R. Wiesnet and David F. McGinnis, National Oceanic and Atmos- pheric Administration ___________________________________ 176 FIGURE 128. Composite of parts of three different ERTS—1 images (band 4) showing retreat of snowpack at three stages during the spring of 1973 _________________________________________________ 177 Surging and nonsurging glaciers in the Pamir Mountains, U.S.S.R., by Robert M. Krimmel, Austin Post, and Mark F. Meier, U.S. Geo- logical Survey __________________________________________ 178 FIGURE 129. Color composite ERTS—1 image of the Pamir Mountains, U.S.S.R. 179 Xll Measuring the motion of the Lowell and Tweedsmuir surging glaciers of British Columbia, Canada, by Austin Post, Mark F. Meier, and Lawrence R. Mayo, US. Geological Survey ______________ FIGURE 130. Color composite ERTS—1 image of the Lowell Glacier and Tweeds- muir Glacier areas of British Columbia, Canada _____________ 131. Annotated ERTS—1 image of the Lowell and Tweedsmuir Glaciers, British Columbia, Canada ________________________________ 132. Graph showing velocity of movement of the Tweedsmuir Glacier in 1973 ___________________________________________________ 133. Maps showing displacement vectors and changes in medial moraines of the Lowell Glacier, 1954—73 ___________________ Monitoring the motion of surging glaciers in the Mount McKinley massif, Alaska, by Mark F. Meier, U.S. Geological Survey _____ FIGURE134. Color composite ERTS—1 image of the Mount McKinley area, Alaska __________________________________________________ 135. Annotated enlargement of ERTS—1 image of the Mount McKinley area, Alaska _____________________________________________ Vatnajokull icecap, Iceland, by Richard S. Williams, Jr.. US. Geological Survey ________________________________________________ FIGURE 136. Annotated enlargement of ERTS—1 image of the Vatnajokull area, Iceland, in the winter ___________________________________ 137. Annotated color composite ERTS—1 image of the Vatnajokull area Iceland, in the summer ___________________________________ 138. Annotated color composite ERTS—1 image of the Vatnajokull area, Iceland, in the fall ______________________________________ 139. Sketch map of the Vatnajokull area of Iceland _________________ Glaciology in Antarctica, by William R. MacDonald, US. Geological Survey ________________________________________________ FIGURE 140. Enlargement of ERTS—1 image of Erebus Ice Tongue, Antarctica__ 141. ERTS—1 image of Ronne Ice Shelf, Antarctica __________________ 142. Sketch map of the Liitzow-Holm Bay area of Antarctica compiled from ERTS imagery ________________________________________ Monitoring flood inundation, by Roger B. Morrison and P. Gary White, U.S. Geological Survey __________________________________ FIGURE 143. Annotated ERTS—1 image showing confluence of the Mississippi and Ohio Rivers in preflood condition on Nov. 24, 1972 _______ 144. Annotated ERTS—1 image showing confluence of the Mississippi and Ohio Rivers in flood on May 5, 1973 _______________________ 145. Annotated ERTS—1 image showing confluence of the Mississippi and Ohio Rivers as rivers retreat to normal stage on June 10, 1973___ 146. Annotated ERTS—1 image of the St. Louis area, Missouri, showing preflood conditions of the Missouri, Mississippi, and Illinois Rivers on Aug. 28, 1972 ___________________________________ 147. ERTS—1 image showing flood swollen rivers in the St. Louis area on Mar. 31, 1973 ________________________________________ 148. Preflood color composite ERTS—1 image of Gila River Valley, Ari- zona, on Aug. 22, 1972 ___________________________________ 149. Color composite ERTS—1 image shows dramatic increase in the San Carlos Lake and soil erosion areas upstream that resulted from the flood of Oct. 21, 1972 ___________________________ 150. Preflood ERTS—1 image (band 7) of the Gila River Valley, Arizona, on Aug. 22, 1972 _________________________________________ 151. Postflood ERTS—1 image (band 7) of the Gila River Valley, Arizona, on Nov. 2, 1972 _________________________________________ 152. Preflood ERTS—1 image (band 5) of the Gila River Valley, Arizona, on Aug. 22, 1972 ________________________________________ 153. Postflood ERTS—1 image (band 5) of the Gila River Valley, Arizona, on Nov. 2, 1972 _________________________________________ 1‘54. Preflood ERTS—1 image of southwestern Iowa on Aug. 14, 1972 ___ 155. Annotated ERTS—1 image mosaic showing the West and East Nish- nabotna Rivers in flood on Sept. 19, 1972 __________________ 180 181 182 183 184 185 186 187 188 189 191 192 193 194 194 194 195 196 197 199 200 201 202 203 204 205 205 206 206 207 208 Xlll ——7 Optical processing of ERTS data for determining extent of the 1973 Mis- sissippi River flood, by Morris Deutsch, U.S. Geological Survey_ 209 FIGURE 156. Preflood and flood ERTS—1 image mosaics of the central Mis- sissippi valley, 1972—73, compared with optically combined temporal color composite image mosaic to show areas of flood- ing ____________________________________________________ 211 157. Temporal color composite of preflood October ERTS—1 image and postflood March and May ERTS—1 images of the St. Louis area__ 212 Monitoring cloud-seeding conditions in the San Juan Mountains of Colorado, by Archie M. Kahan, Bureau of Reclamation ________ 214 FIGURE 158. Annotated color composite ERTS—1 image of the San Juan Moun— tain region, Colorado, showing location of data collection plat- forms __________________________________________________ 215 159. Wolf Creek Pass data collection platform _____________________ 216 TABLE 1. Samples of Project Skywater DCS platform data __________________ 216 Hydrology of arid and semiarid areas, by J. Robert Owen and Lynn M. Shown, US. Geological Survey _________________________ 217 160. Annotated color composite ERTS—1 image of the northern Colorado Plateau _________________________________________________ 218 References ___________________________________________________ 220 Chapter 4. Applications to Land-Use Mapping and Planning Introduction, by James R. Anderson, US. Geological Survey _________ 223 Land use in northeast Colorado, by Larry D. Cast, Bureau of Reclama— tion ___________________________________________________ 225 FIGURE 161. Color composite ERTS—1 image of the South Platte River val- ley, Colorado ___________________________________________ 226 162. Annotated ERTS—1 image of the South Platte River valley showing irrigated lands, grasslands, and dryland farming areas ________ 227 Thematic mapping of forested and cultivated land in Alabama, by Gary W. North, US. Geological Survey, and Neal G. Lineback, Uni- versity of Alabama ______________________________________ 228 FIGURE 163. Color composite ERTS-1 image mosaic of the State of Alabama__ 229 Monitoring change in land use over large regions, by John L. Place, US. Geological Survey ___________________________________ 230 FIGURE 164. Color composite ERTS—1 image of the Phoenix area, Arizona ___ 231 . 165. Land-use map of the Phoenix area, 1970, with changes detected by ERTS through April 1973 __________________________________ 232 166. Color composite ERTS—1 image of the Phoenix area, Arizona, on Oct. 16, 1972 ____________________________________________ 233 Computer-aided mapping of land use, by Richard Ellefsen, California State University, and Leonard Gaydos and James R. Wray, US. Geological Survey ______________________________________ 234 FIGURE 167. Color composite ERTS—1 image of the San Francisco Bay area, California _______________________________________________ 235 168. Enlarged aerial photograph-map pair of Hayward, California _____ 237 169. Part of a computer-classified land-use map of the San Francisco Bay re ion ______________________________________________ 238 170. Map, ort ophotograph, two enlargements of color composite ERTS—1 images, and computer-classified land—use map of a small area near Phoenix, Arizona _______________________________ 239 171. Color composite ERTS—1 image of Phoenix, Arizona, on Oct. 16, 1972 ___________________________________________________ 240 172. Color composite ERTS—1 image of Phoenix, Arizona, on May 2, 1973 ___________________________________________________ 241 References _____._____________________-_______-_____' ____________ 242 XIV Chapter 5. Applications to Agriculture, Forestry, and Rangeland Management Introduction, by Grover Torbert, Bureau of Land Management _______ Monitoring forest-fire burn areas in Alaska, by Grover Torbert, Bureau of Land Management ____________________________________ FIGURE 173. Annotated color composite ERTS—1 image of a forest fire in north- ern Alaska ______________________________________________ Detection of short-term changes in vegetation of southern Arizona, by Raymond M. Turner, US Geological Survey ________________ FIGURE 174. Color composite ERTS—1 image of the Tucson area, Arizona_-__ 175. Thematic extraction of relatively dense vegetation from ERTS—1 images by ratioing (late summer, winter, and spring) ________ Monitoring ephemeral livestock-forage production, by R. Gordon Bentley, Jr., Bureau of Land Management __________________ FIGURE176. Color composite ERTS—1 image of the Phoenix area, Arizona" 177. Annotated color composite ERTS—1 image of the Phoenix area, Arizona, showing perennial and ephemeral vegetation and pro- duction _________________________________________________ References __________________________________________________ Chapter 6. Applications to Environmental Monitoring Introduction, by C. F. Withington, US. Geological Survey ___________ Changes in landscape due to strip mining, by John B. Rehder, Uni- versity of Tennessee ____________________________________ FIGURE 178. Changes in the landscape created by strip mining on the Cumber- land Plateau, Tennessee, Apr. 18 through Oct. 15, 1972, from aerial photography and ERTS—1 imagery ____________________ 179. Strip mines on the Cumberland Plateau from enlargement of ERTS— 1 image acquired on Oct. 15, 1972 _________________________ 180. Strip mines on the Cumberland Plateau from NASA high—altitude aerial photography acquired on Apr. 18, 1972 _______________ Oil-well fire on ERTS—1 images, by C. F. Withington, US. Geological Survey, and Roy M. Breckenridge, Wyoming Geological Sur- vey ___________________________________________________ FIGURE181. Smoke plume from wildcat oil-well fire, Converse County, Wyom- ing, on ERTS—1 image, Dec. 20, 1973 _____________________ 182. Enlargements of three ERTS—1 images showing comparison of reflectance of smoke plume ______________________________ Air pollution from the Ohio River and Monongahela River valleys, by Fred R. Brown and Fred S. Karn, US. Bureau of Mines ___________ FIGURE 183. Color composite ERTS—1 image of smoke plumes from power- generating plants in the Ohio River and Monongahela River valleys __________________________________________________ 184. Index map of the Ohio River and Monongahela River valleys ____ 185. Enlargement of part of image of the Beverly, Ohio, area showing smoke plumes on different MSS bands on Jan. 12, 1973 ________ 186. Enlarged parts of four ERTS—1 images showing steam plumes from coke ovens near Pittsburgh, Pennsylvania, November 1972 through March 1973 ____________________________________ A Lake Michigan ”Whiting,” by Alan E. Strong, National Oceanic and Atmospheric Administration ______________________________ FIGURE 187. Color composite ERTS—1 image mosaic of Lake Michigan ______ 188. Nonconventional color composite ERTS—1 image mosaic of Lake Michigan to emphasize ”whiting" phenomenon ______________ 189. ERTS—1 image mosaic of band 4 images of Lake Michigan _____ 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 XV Algal blooms in Utah Lake, by Alan E. Strong, National Oceanic and Atmospheric Administration ______________________________ FIGURE 190. Color composite ERTS—1 image of algal blooms in Utah Lake ___ 191. Comparison of a part of ERTS—1 image, showing algal blooms in Utah Lake on bands 4, 5, 6, and 7 __________________________ Wetland classification and mapping along the south Atlantic coast, by Virginia Carter, US. Geological Survey, and Richard R. Ander- son and John W. McGinness, Jr., The American University -___ FIGURE 192. Enlargement of part of band 7 ERTS—1 image of the Charles— ton area, South Carolina ________________________________ 193. Wetland map of the Charleston, Lake Moultrie, and Cooper River area, South Carolina _____________________________________ 194. ERTS—1 image of the Charleston area, South Carolina, showing wet- land vegetation on Oct. 12, 1972 __________________________ 195. ERTS-1 image of the Charleston area, South Carolina, showing wet— land vegetation on Mar. 23, 1973 __________________________ Coastal wetland mapping in the central Atlantic region, by Virginia Carter, US. Geological Survey, and Richard R. Anderson, The American University ____________________________________ FIGURE196. Color composite ERTS—1 image of the lower Chesapeake Bay __ 197. Enlargement of band 7 ERTS—1 image of the Chincoteague Bay salt-marsh complex _______________________________________ 198. Wetland map of the Chincoteague Bay salt—marsh complex ______ Computer mapping of coastal wetlands, by Virginia Carter, U.S. Geolo- gical Survey ____________________________________________ FIGURE199. Color composite ERTS—1 image of the Chincoteague Bay area of the Virginia Eastern Shore On Aug. 30, 1973 _________________ 200. Computer—processed wetland map of the Chincoteague Bay salt- marsh complex __________________________________________ Tidal effects in coastal wetlands, by Virginia Carter, US. Geological Survey, and Richard R. Anderson, The American University ___- FIGURE 201. Color composite ERTS-1 image of the Georgia-South Carolina coast and band 7 ERTS—1 image of Port Royal Sound, South Carolina, on June 3, 1973, at high tide ______________________________ 202. Color composite ERTS—1 image of the Georgia-South Carolina coast and band 7 ERTS—1 image of Port Royal Sound, on Apr. 28, 1973, at low tide ________________________________________ Wetland mapping in a large tidal brackish-water marsh in Chesapeake Bay, by Virginia Carter, US. Geological Survey, John W. Mc- Ginness, Jr., and Richard R. Anderson, The American University FIGURE 203. Color composite ERTS—1 image of the Delmarva Peninsula and band 7 ERTS—1 image of Nanticoke Marsh on Oct. 10, 1972 ___ 204. Color composite ERTS—1 image of the Delmarva Peninsula and band 7 ERTS-1 image of Nanticoke Marsh on July 7, 1973 ___- 205. Wetland map of Nanticoke Marsh compiled from ERTS images __e Environmental assessment of remote areas of Colombia, South Ameri- ca, by William D. Carter, US. Geological Survey ___________ FIGURE 206. Color composite ERTS—1 image of southeastern Colombia, South America ________________________________________________ 207. A portion of U.S. Air Force Operational Navigation Chart (ONC L 26) of southeastern Colombia _____________________________ Man's impact upon wetlands, by Virginia Carter, US. Geological Sur- vey, and Linda Alsid and Richard R. Anderson, The American University _____________________________________________ FIGURE 208. Color composite ERTS—1 image of the New Jersey-Delaware coastal wetlands _________________________________________ 209. Color composite ERTS—1 image of the Georgia coastal wetlands near Savannah _______________________________________________ XVI 270 271 272 273 274 274 275 276 277 278 279 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 Selection of a road alinement through the Great Kavir in Iran, by Daniel B. Krinsley, US. Geological Survey __________________ FIGURE 210. Index map of Iran showing location of the Great Kavir ________ 211. Color composite ERTS—1 image of the Great Kavir in its driest period on Sept. 20, 1972 _________________________________ 212. Color composite ERTS—1 image of the Great Kavir in its wettest period on May 12, 1973 __________________________________ Tornado tracks, by Este F. Hollyday, US. Geological Survey, and James G. Cook, US. Army Corps of Engineers _____________________ FIGURE 213. Color composite ERTS—1 image of tornado tracks in the William B. Bankhead National Forest near Guin, Alabama ____________ References ___________________________________________________ Chapter 7. Applications to Conservation Introduction, by Richard D. Curnow, US Fish and Wildlife Service -_ Archaeological analysis of imagery of Chaco Canyon region, New Mexico, by Thomas R. Lyons and James I. Ebert, National Park Service, and Robert K. Hitchcock, University of New Mexico--- FIGURE 214. Index map showing location of the Chaco Canyon National Monu- ment, New Mexico -------------------------------------- 215. Color composite ERTS—1 image of the Chaco Canyon National Monument, New Mexico -------------------------------- Cape Cod and the Cape Cod National Seashore of Massachusetts, by Richard S. Williams, Jr., US Geological Survey ------------- FIGURE 216. Color composite ERTS—1 image of the Cape Cod area of Mas- sachusetts ----------------------------------------------- 217. Part of the Boston sheet of the International Map of the World showing the same area as figure 216 ----------------------- Land-use planning in Yellowstone National Park, Wyoming, Montana, and Idaho, by Harry W. Smedes, U.S. Geological Survey ------ FIGURE 218. Color composite ERTS—1 image of the Yellowstone National Park and vicinity on Nov. 23, 1972 ---------------------------- 219. Color composite ERTS—1 image of the Yellowstone National Park and vicinity on Aug. 7, 1972 ------------------------------- 220. High-filtitude color aerial photomosaic of the Yellowstone National Par ---------------------------------------------------- 221. Computer-processed terrain map of the Yellowstone National Park made from computer compatible tapes --------------------- The Great Dismal Swamp of Virginia and North Carolina, by Virginia Carter, US. Geological Survey FIGURE 222. Map of the Great Dismal Swamp study area, Virginia-North Carolina ------------------------------------------------ 223. Enlargement of part of color composite ERTS—1 image showing the Great Dismal Swamp ------------------------------------- 224. Color composite ERTS—1 image of northern Pamlico Sound and the Great Dismal Swamp with partial snow cover on Feb. 13, 1973 -- 225. Color digital display of the Great Dismal Swamp in simulated false- color infrared ------------------- 226. Thematic extraction of Atlantic white-cedar, Great Dismal Swamp-- 227. Thematic extraction of surface water below deciduous trees, Great Dismal Swam ------------------------------------- 228. Thematic extraction of drier deciduous areas, Great Dismal Swamp 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 313 314 315 316 317 317 319 320 320 320 320 XVll Monitoring breeding habitat of migratory waterfowl, by David S. Gil- mer and A. T. Klett, US. Fish and Wildlife Service, and Edgar A. Work, Environmental Research Institute of Michigan _______ TABLE 2. Part of a computer printout for the July 7, 1973, ERTS—1 image (fig. 230) showing size-frequency distribution of surface water and loca- tion and size of water bodies _________________________________ FIGURE 229. Index map showing coverage provided by three ERTS images in a primary waterfowl—breeding area in North Dakota _________ 230. Color composite ERTS—1 image showing waterfowl-habitat study area near Jamestown, North Dakota ________________________ References ___________________________________________________ Chapter 8. Applications to Oceanography Introduction, by William J. Campbell, US. Geological Survey ________ Mapping surface current flow in turbid nearshore waters of the north- east Pacific, by Paul R. Carlson, US. Geological Survey _______ FIGURE 231. Winter ERTS—1 image of turbid-water plumes along the northern California coast on Jan. 6, 1973 ___________________________ 232. Spring ERTS-1 image of turbid—water plumes along the northern California coast on Apr. 24, 1973 __________________________ Detection of turbidity dynamics in Tampa Bay, Florida, by A. Eugene Coker, Aaron L. Higer, and Carl R. Goodwin, U.S. Geological Survey ________________________________________________ FIGURE 233. Color dcomposite ERTS—1 RBV image of the Tampa Bay area of Flori a _________________________________________________ 234. Oblique aerial photograph of shell-dredging operations and tur- bidity plume ____________________________________________ 235. Sketch map showing turbidity in Tampa Bay ___________________ 236. Velocity-vector grid of turbidity in Tampa Bay __________________ 237. Black and white photograph of RBV bands enchanced by a color- additive viewer and sketch map of turbidity plume ___________ Movement of turbid-water masses along the Texas coast, by Ralph E. Hunter, U.S. Geological Survey ___________________________ FIGURE 238. Turbidity patterns in the Gulf of Mexico and Galveston Bay on an- notated ERTS—1 image ___________________________________ 239. Turbidity patterns along the Texas coast between Galveston and Pass Cavallo on annotated ERTS—1 image ____________________ Tracking ice floes by sequential ERTS imagery, by William J. Camp- bell, U.S. Geological Survey ______________________________ FIGURE 240. Ice floes in eastern Beaufort Sea in the Arctic on ERTSe1 image of Aug. 19, 1972 ________________________________________ 241. Map showing trajectories of two ice floes _____________________ Ice lead and polynya dynamics, by William J. Campbell, U.S. Geologi- cal Survey _____________________________________________ FIGURE 242. ERTS—1 image of the ice cover in the central Beaufort Sea on Apr. 5, 1973 ___________________________________________ 243. ERTS—1 image of the ice cover in the central Beaufort Sea on Apr. 6, 1973 _________________________________________________ Seasonal metamorphosis of sea ice, by William J. Campbell, U.S. Geo- logical Survey __________________________________________ FIGURE 244. ERTS—1 image mosaic of large ice floes in the eastern Beaufort Sea on June 16, 1973, before onset of the summer melt ________ 245. ERTS—1 image mosaic of large ice floes in the eastern Beaufort Sea 17 days later ____________________________________________ XVIII 321 322 323 324 325 326 328 329 329 330 331 332 332 332 333 334 335 336 337 338 339 340 341 342 343 344 345 Dynamics of arctic ice-shear zones, by William J. Campbell, U.S. Geo- logical Survey 346 FIGURE 246. ERTS—1 image of northwest coast of Banks Island Northwest Ter- ritories, Canada, on Apr. 10, 1973 __________________________ 347 247. ERTS—1 image of northwest coast of Banks Island, Northwest Ter- ritories, Canada, 24 hours later ____________________________ 348 248. ERTS—1 image of northwest coast of Banks Island, Northwest Ter- ritories, Canada, 17 days after figure 247 was imaged _________ 349 Morphology of Beaufort Sea ice, by William J. Campbell, U.S. Geologi- cal Survey _____________________________________________ 350 FIGURE 249. ERTS—1 image mosaic of eastern Beaufort Sea on Aug. 22, 1972 __ 351 250. ERTS—1 image mosaic of western Beaufort Sea on Aug. 22, 1972-- 353 251. ERTS—1 Image mosaic of eastern Beaufort Sea area on Sept. 8, 1972 354 252. Polar projection map of the North Pole from Nimbus—5 ESMR data- 355 Flooding of sea ice b y the rivers of northern Alaska, by Peter W. Barnes and Erk Reimnitz, U.S. Geological Survey ___________________ 356 FIGURE 253. ERTS—1 image showing an area of river flooding on sea ice near Prudhoe Bay, Alaska, on May 24, 1973 _____________________ 357 254. ERTS—1 image showing an area of river flooding on sea ice near Prudhoe Bay, Alaska, on May 26, 1973 _____________________ 358 255. ERTS—1 image showing an area of river flooding on sea ice near Prudhoe Bay, Alaska, on May 27, 1973 _____________________ 359 Influence of sea ice on sedimentary processes off northern Alaska, by Erk Reimnitz and Peter W. Barnes, US. Geological Survey--- 360 FIGURE 256. Annotated color composite ERTS—1 image of the Prudhoe Bay area, Alaska, on June 14, 1973 ________________________________ 361 References __________________________________________________ 362 CONVERSION TABLE IBM ______ International Business Machines. IMW _____ International Map of the World. 1 board foot measure:144 cubic inches. JTU —————— Jackson turbidity units. 1 centimeter:0.39 inch. K ———————— '93le- 1 hectare=2.47 acres. kg ——————— kilogram. 1 kilogram=2.2 pounds. km ——————— kilometer. 1 kilometer=0.62 mile. km/h _____ kilometers per hour. 1 liter per second=0.04 cubic foot per second. k" ——————— kPOtS- 1 meter=3.28 feet. kWh —————— kilowatt hour. 1 micrometer=0.00004 inch. lat ——————— 'ét'tUde- 1 microradian=0.057 degree. V5 ——————— llter€ per SGCOHd- 1 millimeter=0.04 inch. long ————— longitude. 1 nautical mile=1.15 statute miles. m ———————— meter. m/s ______ meters per second. ,um _______ micrometer. ABBREVIATIONS urad ______ microradian. mg/l _____ milligrams per liter. A ________ Angstrom (=nanometer). mm ______ millimeter. AIDJEX ___Arctic Ice Dynamics Joint Experiment. min ______ minute. C ________ Celsius. mo _______ month. cm _______ centimeter. MSS ______ multispectral scanner. CCI' ______ computer compatible tape. NASA ____National Aeronautics and Space Administration. ma _______ cubic meter. NOAA ____National Oceanic and Atmospheric Administration. m‘/s ______ cubic meters per second. nmi ______ nautical miles. DCP ______ data collection platform. pixel _____ picture element of ERTS—1 image (unit of area DCS ______ data collection system. measurement: 79m X56m) EROS _____ Earth Resources Observation Systems. PDP ______ Programmable Digital Processor. ERTS _____ Earth Resources Technology Satellite. RBV ______ return beam vidicon. ESIAC ____electronic satellite image analysis console. rms ______ root mean square. ESMR _____ electronically scanning microwave radiometer. s ________ second fbm ______ foot board measure. km” ______ square kilometer. g-cal _____ gram-calorie t _________ tonne (1 03 kg). G.m.t. ___..Greenwich mean time. UTM _____ Universal Transverse Mercator. ha _______ hectare. VHRR ____very high resolution radiometer. h ________ hour. yr _______ year. XIX ERTS-1, A NEW WINDOW ON OUR PLANET Richard S. Williams, Jr., and William D. Carter, Editors INTRODUCTION By John M. DeNoyer, US. Geological Survey land areas of the world; the ERTS—l spacecraft has accomplished approximately 80 percent of this task. The data base acquired by ERTS—l is also a documentation of environ— mental conditions for the entire North American continent. This documenta- tion will be of critical importance and will form a baseline for the recognition of environmental changes that may occur in the future. The capability to make continued comparable observations will be necessary to use effectively and wisely this baseline of information. An objective, factual data base will be essential to both developers and environmentalists as large-scale resource production is pursued. The ERTS spacecraft is providing a data base that is used by many scientific disciplines. The fact that a common data base is useful to so many ‘ is a significant accomplishment in itself, establishing interdisciplinary com- r munications and evolving multidisciplinary programs. The advantages of newly established channels of scientific communication may well be as impor- tant as many of the benefits to individual disciplines. The entire North American continent has been imaged at least once during the ERTS—l experiment; many parts of North America have been imaged several times. This repetitive coverage has provided a data base used in examining changes that occur from natural and manmade causes and has opened a new field for documenting and understanding changes that occur on the surface of the Earth. No longer is it assumed that a one-time picture accurately describes the surface phenomena. Optimum times for observing different phenomena vary seasonally. For example, the total extent of forests can be mapped during the summer. Separation of deciduous trees and ever- greens can be more easily accomplished using both summer and winter imagery. The relation of vegetation to soil moisture, soil type, and underlying geology is also more apparent by seasonal observations. Topographic features are made more apparent by thin snow cover or water-saturated soil. Observing these changing conditions at any one location will require a number of years, if not decades, for data acquisition. The optimum interpretation often requires observation under different conditions (for example, low Sun angle of illumi- ! n objective of the ERTS Program is to obtain one-time imaging of the 1 2 ERTS—1, A New Window on Our Planet nation) even though the phenomena being observed (such as topography) may be relatively static. The ERTS spacecraft is in a near—polar orbit; it travels around the Earth every 103 min and can image selected portions of the Earth on each orbit. The satellite has capability for international data acquisition, and international interest in the initial ERTS investigations was in fact high. An even larger number of proposals for follow—up international investigations has been submitted. International training courses and workshops in the use of ERTS data have been conducted during the past few years, and plans call for a continuation of these training programs. Some nations have made major investments to be able to utilize ERTS data effectively. Canada and Brazil have constructed data-reception and data—processing facilities that are being used directly with ERTS, and other nations are actively negotiating with NASA to create similar capabilities. Data from ERTS can be interpreted through analysis of photographic- type images or through highly sophisticated automatic information—extraction procedures. Every gradation between these two extremes of sophistication in analytical methods can be found in the data utilization program. This range of techniques opens the door for wide and extensive benefits to be obtained by a large segment of the world’s population. All data received and processed from ERTS are available to anyone ' throughout the world. Several data formats are available to match user’s needs, but the investigator can do additional processing to meet his specific needs. The contributions included in this professional paper illustrate a number of applications of ERTS data. Several additional studies are also being conducted. Technical reports on the NASA-sponsored ERTS investiga- tions can be obtained through the Department of Commerce, National T ech- nical Information Service (NTIS), Springfield, Virginia 22151. Summaries of results are published on a weekly basis. Topics of interest can be identified from these summaries, and brief interim or comprehensive final reports can be obtained from NTIS. A number of scientific symposia and other meetings have been convened since the launch of ERTS—l. The ERTS—l spacecraft and ground processing system have been an . outstanding technological success, a good example of the application of space technology to the solution of man’s problems on Earth. ERTS-l MSS FALSE-COLOR COMPOSITES By Charles F. Withington, U.S. Geological Survey imagery taken by NASA’S ERTS—l from an altitude of 915 km. Such a picture is the one of the upper Chesapeake Bay area (fig. 1). The scale of an 18.5- x 18.5—cm image (9- X 9-in. print) is 1 :1,000,000; each image en— compasses an area of 34,000 kmz. The four black and white ERTS MSS images (:figs. 2—5) are in four different bands of the electromagnetic spectrum (fig. 6): the green band (designated band 4 on ERTS imagery) approximately 0.5—0.6 mm; the red band (band 5) approximately 0.6—0.7 ,um; and 2 bands in the near-infrared range, band 6, 0.7—0.8 mm and band 7, 0.8—1.1 am. The two infra: red bands measure the reflectance of the Sun’s rays ofl' the surface of the Earth outside the range of light sensitivity of the human eye. One of the best reflect- ing materials is chlorophyll; generally speaking, the healthier the vegetation, the brighter the reflectance. False-color imagery is made by projecting the different bands through the proper filters and combining them. Red is as- signed to the near-infrared, thus vegetation appears red; the healthier the vegetation, the redder the image. Water absorbs the Sun’s rays, so clear water appears black on infrared. However, silt in water reflects the Sun’s rays and appears light blue on the image. Buildings and roads of cities also appear in bluish-gray hues. In the image of the upper Chesapeake Bay area (fig. 1), taken Oct. 11, 1972, the predominant feature is Chesapeake Bay extending from north to south near the eastern edge of the image. The Delmarva Peninsula is east of the bay. Baltimore, Md., is near the top center; Washington, DC, is just left of theeenter of the image. The vigorous vegetation of urban open spaces can be easily seen, such as the Mall and Hains Point in Washington. Urban areas stand out plainly; notice the growth patterns radiating out from the larger cities. Urban and suburban growth can be measured and monitored with subsequent ERTS images, providing valuable information for regional and transportation planners. Notice that part of the course of the Potomac River (center part of image) is light blue. This is the silt that resulted from a storm that traveled northward up the coast on October 5—7 and .dumped more than 25 mm of rain on the headwaters of this river. Tidal action has restricted the dispersion of sediment in the estuary of this river. The bare ground (white) seen east of Chesapeake Bay are fields from which crops have been harvested. The redder tone in the far upper right is a F alse—color or color-infrared composite pictures are made from multispectral 3 I 81.0 > (40le ODIWQOZI so-maozl IOU ' (131.085 4 ERTS—1, A New Window on Our Planet IHB77-30 u677-BOI ‘NB78-381 H878-88I |IOCT72 C N38-54/N076-48 N N38-52/HB78-43 H88 U SUN EL38 92149 iSI l||4-N-|-N-D-2L NRSR ERTS E-1888-15182-‘ 8| APPROXIMATE SCALE 10 0 10 20 30 MIL ES | J l 1 1 1 1 l I l""l I I i 10 0 10 20 30 KILOMETERS FIGURE 1.—Annotated color composite ERTS—1 image of the upper Chesapeake Bay area made by combining bands 4, 5, and 7 (1080—15192L OU'MMQEI as-wwozl ISUIWMOZ MSS False-Color Composites 5 FIGURE 2.——ERTS—~1 image of the upper Chesapeake Bay area, showing re- FIGURE 3.—ERTS—1 image of the upper Chesapeake Bay area, showing re— flectance in the 0.5- to 0.6-,Lm (green) range of the spectrum (1080—— flectance in the 0.6- to 0.7-,um (red) range of the spectrum (1080—15192, 15192, band 4). band 5). FIGURE 4.——ERTS—1 image of the upper Chesapeake Bay area, showing re- FIGURE S.—ERTS—1 image of the upper Chesa peake Bay area, showing re— flectance in the 0.7— to 0.8mm (near-infrared) range of the spectrum erctance in the 0.8- to 1'17““ (near-infrared) range of the spectrum [1080—15192, band 6). (1080—15192, band 7). APPROXIMATE SCALE 10 o 10 20 30 4o 50 MILES J | I I I I I I I I”I ' i I i I I 10 o 10 20 30 4o 50 KILOMETERS 6 ERTS—1, A New Window on Our Planet RBV 330d Band Band 1 2 3 M88 Band Band Band Band 4 5 6 7 l L ,4 \ .5 .6 ,7 .8 .9 1.0 / 1.11-tm \ / \ / \\ // \ / \\ / / \ \ Frequency (cycles/sec)/ \ / 14 / 12 10 \ 2 16 \ 10 / 10 s 10 10 Microwave Wave length 15,000 nm I: - O O O I\ Scanners with filtered photomultipliers: image orthicons and cameras with filtered infrared film >2900 nm Cameras with infrared sensitive film; solid-state detectors in » scanners and radiometers Radar; radio-frequency receivers in scanners and radiometer: FIGURE 6.—The electromagnetic spectrum and ERTS—1 sensor relationships. (Modified from Parker, D. C., and Wolff, M. F., 1965, Remote sensing: international Science and Technology, July.) poorly drained area where the fields are small, the land less fertile, and the forested area more extensive. Geologic structures show up particularly well. The elongate forested areas in the upper left of the picture, for instance, are the Blue Ridge Mountains. Lineaments can be seen throughout the area, especially the northeast-trending lineaments north of Baltimore and the north—trending lineament parallel to the upper right edge of the image. The following list is a guide to the image information at the bottom of all original ERTS images. Enlargements and specially processed ERTS images may not include such image data, however. Description of annotation at margins of an E RTS image 110CT72—Day, month, and year of image exposure. C N38—54/W076—48—Ge0metric extensions of spacecraft yaw attitude axis to Earth’s surface: C—Format center, latitude/ longitude, degrees-minutes. N N38—52/WO76—43——Intersection with Earth’s surface of a line from the satellite perpendicular to Earth ellipsoid: N—Nadir, latitude/ longitude, degrees-minutes. MSS 457D—Sensor used (MSS~MultispectI-al Scanner, RBV—Return Beam Vidicon): Band or bands, in this case a color composite of bands 4, 5, and 7. ' D—Direct. R—Recorded type of transmission. MSS False-Color Composites 7 SUN EL38 AZl49—Sun angles specified at time of M88 midpoint or RBV time of exposure to nearest degree: EL—Elevation. AZ—Azimuth. 191—Spacecraft heading, including yaw (toward image annotation). 1114—Orbit revolution number since time of launch. N—U.S. ground recording station: N—Greenbelt, Md. A—Alaska. G—Goldstone, Calif. l—Image size: 1—100 nmi X 100 nmi. 2—50 nmi X 50 nmi. 3—25 nmi X 25 nmi. N—Image processing procedure: N—Normal. A—Abnormal. D—Orbit ephemeris data: D—Definitive. P—Predicted. 2—Mode of M88 signal processing before transmission from satellite: l—Linear. 2—Compressed. L—Gain: L—Low gain. H—High gain. NASA/ERTS—Agency and project identifier. E—1080—15192—Frame identification number. E—Encoded project identifier. l—ERTS mission (1—-ERTS—A, 2—ERTS—B; after 999 days, numbers change to 5 and 6, respectively). 080—Day number relative to launch at time of observation. 15—Hour at time of observation (G.m.t.). 19—Minute at time of observation (G.m.t.). 2—Seconds at time of observation (G.m.t.) rounded off to the nearest 10 s. 4/5/7—Band number: RBV: 1(0.475—0.575 ,um), 2(0.580—0.680 ,um), 3(0.630—0.830 ,um) MSS: 4(0.5~0.6 pm), 5(0.6—0.7 ,um), 6(0.7—0.8 ,am), 7(0.8—1.1 ,um) Color composite: 4/5/7 Ol—Regeneration number Tic marks and numbers around. margins of the ERTS image refer to an approximate latitude and longitude (degrees and minutes) grid for the image. Note: The original M88 or RBV ERTS image is created on photographic film from an electron beam recorder at a scale of 1:3,360,000. Negative or positive transparencies or prints (black and white or false-color) are available at this scale or at standard enlargement scales of 1:1,000,000; 1:500.000; 1:250,000 from the EROS Data Center, Sioux Falls, S. Dak. 57198. Computer compatible tapes (CCT’s) of every ERTS image are also available from the EROS Data Center. As an example of how the satellite images the surface of the Earth on successive orbits, the dates and orbit numbers for ERTS—l from Aug. 3, 1974, to Jan. 11, 1975, over the conterminous United States and from Apr. 17, 1974, to Aug. 20, 1974, over Alaska and Hawaii are shown on the following pages. ERTS—l COVERAGE OF 124° 1 / 122” 120° 118“ 116° 114° 112° 110° 108° 106° 104° 102° 100° 98° 96° 94° /’111111411 ASHER; I I \‘Wfi‘K ‘/ / UREGO N 2 I DA H 0 I I N TON 1 \ 5 MONTANA NORTH DA KO'I‘A 1, vwfl ~ V /1 “I‘M. : ’ FITN‘J“ U’I‘AH / I NEVA ) 4 A \ [1" “Al ‘ \\ A ‘4 \ I I I I ('UU IRA DU ARIZONA 1' N E W M EX N10 Ii '7‘“ m. I I r I 1 DATE 8/8 8/7 8/6 8/5 8/4 8/3 8/20 8/19 8/18 3/17 8/16 8/15 8/14 8/13 8/12 8/11 8/10 8/9 8/8 8/7 8/6 8/5 ORBIT NO. 10403 10389 10375 10361 10347 10333 10570 10556 10542 10528 10514 10500 10486 10472 10458 10444 10430 10416 10402 10388 10374 10360 8/26 8/25 8/24 8/23 8/22 3/21 9/7 9/6 9/5 9/4 9/3 9/2 9/1 8/31 8/30 8/29 8/28 8/27 8/26 8/25 8/24 8/23 10654 10640 10626 10612 10598 10584 10821 10807 10793 10779 10765 10751 10737 10723 10709 10695 10681 10667 10653 10639 10625 10611 9/13 9/12 9/11 9/10 9/9 9/8 9/25 9/24 9/23 9/22 9/21 9/20 9/19 9/18 9/17 9/16 9/15 9/14 9/13 9/12 9/11 9/10 10905 10891 10877 10863 10849 10835 11072 11058 11044 11030 11016 11002 10988 10974 10960 10946 10932 10918 10904 10890 10876 10862 9/31 9/30 9/29 9/28 9/27 9/26 10/12 10/11 10/10 10/9 10/8 10/7 10/6 10/5 10/4 10/3 10/2 10/1 9/31 9/30 9/29 9/28 11156 11142 11128 11114 11100 11086 11323 11309 11295 11281 11267 11253 11239 11225 11211 11197 11183 11169 11155 11141 11127 11113 10/18 10/17 10/16 10/15 10/14 10/13 10/30 10/29 10/28 10/27 10/26 10/25 10/24 10/23 10/22 10/21 10/20 10/19 10/18 10/17 10/16 10/15 11407 11393 11379 11365 11351 11337 11574 11560 11546 11532 11518 11504 11490 11476 11462 11448 11434 11420 11406 11392 11378 11364 ”/6 11/5 11/4 11/3 11/2 11/1 11/18 11/17 11/16 11/15 11/14 11/13 11/12 11/11 11/10 11/9 11/8 11/7 11/6 11/5 11/4 11/3 11658 11644 11630 11616 11602 11588 11825 11811 11797 11783 11769 11755 11741 11727 11713 11699 11685 11671 11657 11643 11629 11615 11/24 11/23 11/22 11/21 11/20 11/19 12/6 12/5 12/4 12/3 12/2 12/1 11/30 11/29 11/28 11/27 11/26 11/25 11/24 11/23 11/22 11/21 11909 11395 11881 11867 11853 11839 12076 12062 12048 12034 12020 12006 11992 11978 11964 11950 11936 11922 11908 11894 11880 11866 12/12 12/11 12/10 12/9 12/8 12/7 12/24 12/23 12/22 12/21 12/20 12/19 12/18 12/17 12/16 12/15 12/14 12/13 12/12 12/1! 12/10 12/9 12160 12146 12132 12118 12104 12090 12327 12313 12299 12285 12271 12257 12243 12229 12215 12201 12187 12173 12159 12145 12131 12117 12/30 [2/29 12/28 12/27 12/26 12/25 1/11 1/10 1/9 1/8 1/7 1/6 1/5 1/4 1/3 1/2 1/1 12/31 12/30 12/29 12/28 12/27 12411 12397 12383 12369 12355 12341 12578 12564 12550 12536 12522 12508 12894 12480 12466 12452 12438 12424 12410 12396 12382 12368 NOTE: ORBIT TRACKS REPRESENT NOMINAL LOCATIONS BASED ON DATA USERS HANDBOOK TABLES. PE- RIODIC ORBIT DRIFT AND ADJUSTMENTS CAUSE SHIFTS OF UP TO 37 KILOMETERS‘ FOR MORE LOCATIONAL ACCURACY ON A GIVEN DATE, CONTA SPACE FLIGHT CENTER, GREENBELT, MARYLAND CT ERTS USER SERVICES AT THE NASA GODDARD HE UNITED STATES 92° 1 90° 88° 86° 84" 82° 80. I 1 A" JJQWIE 1 "V \VIS ‘ON SI N 96° MiNNEEQTA ‘ '— 1 [OWA S K 94° 1 \ \ ALABA‘M A MiSS . I. 1 1 , ,..A_~ '_ 1 8/4 10346 8/18 10541 8/3 10332 8/20 10569 8/19 10555 8/17 10527 8/13 10471 13/16 10513 8/15 10499 8/14 10485 8/12 10457 8/22 10597 8/21 10583 9/7 10820 9/6 10806 9/5 10792 9/4 10778 9/3 [0764 9/2 10750 SH 10736 8/31 10722 8/30 10708 9/9 10848 9/8 10834 9/25 11071 9/24 1 1057 9123 11043 9/22 1 1029 9/21 11015 9/20 11001 9/19 10987 9/17 10959 9/18 10973 9/27 11099 9/26 11085 10/12 11322 10/11 11308 10/10 11294 10/9 11280 10/8 11266 10/7 11252 [0/6 11238 10/5 11224 10/4 11210 10/14 11350 10/13 11336 10/30 1 1573 10/29 11559 10/23 11545 10/27 11531 10/26 11517 10/25 11503 1 0/24 11439 10/23 11475 10/22 11461 11/2 11601 11/1 11587 11/18 11824 “/17 11810 11/16 11796 11/15 11782 “/13 11754 “/11 11726 11/14 11768 ”/12 11740 11/10 11712 11/20 11852 11/19 11838 12/6 12075 12/5 12061 l2/4 12047 12/3 12033 12/2 12019 12/1 12005 11/29 11977 “/30 11991 11/28 11963 12/8 12103 12/7 12089 12/24 12326 12/23 12312 12/22 12298 12/21 12284 12/20 12270 12/19 12256 12/18 12242 12/17 12228 12/16 12214 12/26 12854 12/25 12340 1/11 12577 1/10 12563 1/9 12549 1/8 12535 1/7 12521 1/5 12493 1/4 12479 1/6 12507 1/3 12465 78° (3 1130 EGXA 13/11 10443 8/29 10694 9/16 10945 [0/3 11196 10/21 11447 11/9 11698 11/27 11949 12/15 12200 1/2 I2451 76° 74° \ Irr~:;§n£QNLMOaO£Q 3 9.8%86 5%: 9: B 33:: lb; 2:858 58 maggot? $50: R3 «0:: «33 4.2.5:; :53: $5.3m 4196303 w 3 >9 3% 10.. 6:: .c 53.5 2 122:. 92 52$ :53 :2 $2 a... , s x , $2£¥22§§4§€s :3 21 xi :2 :z; :33: n , . 5km ,, a 3.; a s 2 CE uzfirzmhzfv 42sz _.I §ncP||I|l|ll|§2 :5: 3|. .I WEI lace i 3 aw nw_:u¥o.=x a 5 g 9583 54.0% .3 . 9 ‘ .4 8,: r ‘ a. ,z 5389: :53. :Qrzyé :52 RS 1 5341.2 3223/. 735:2? ”23:... 5.064152 Ryan $83.. a: v; 3 7148:!» J 1:3 21 a. :25? F. _ (:39 .rxmzv y; 5 §¢z<£ ;. .35 2437,2835: 2:. .55.". Vétfiflaxla 3 «6:23? ,cvuaE pancéidc. «5%: 325 2.5 a. $3538 3 v2.5»? 5&3: .445st m 5:55 4.5.5ch 3 2 ms}; 33 . _. 32555. 2 2 21¢ 15m A Eugfii y... 3 27:11. Eugzye i. .2 27’ 1:: £22,. a. £38 7.523, E 2.5:— 1: : 16:59:52? 2:53— . 4 a. 3. ~2< 555 3:11: a has. 542 :w 2: “£54252? 7?,me 92me AanvaAOmU >45 $554.35 dammb 4523.2. uE. mo Euaxéma 8:5 9:29 Eu an ’ S lsxlfl>x§1K6XS|XV.§3\XX!\3!$ 3.351%) xlxiisliéifi x‘otibmHM xi 3.3!”) ixtxeiiksx 2» xflt ‘1fsx u. 8.! 9 a. m0<2~ DNA—520 mtgfi ~vwhmm 22 ORTHOlMAGE MOSAIC OF NEW JERSEY By Winston Sibert and Fitzhugh T. Clark, US. Geological Survey ne of the more striking products of the ERTS system is the false—color image produced by printing the various bands in difl'erent colors. This printing is facilitated by the inherent registry between the different bands. A natural expansion of this capability has been the production of color pared by the classic method of producing paper prints and joining them on a base board with the best possible fit, the difference being in this case that the prints were in color. The individual sensors for each of the four spectral bands of the ERTS MSS are accurately alined so that the four black and White images, one for 'each band, will all register accurately. Each band is produced by a digital~to~analog conversion of the basic data, which is then recorded on film by an electron beam recorder. The satellite orbital altitude combined with the narrow field of View eliminates the need for rectification. Moreover, measurements have shown that the bulk-processed ERTS imagery has excellent geometric fidelity. The satellite image mosaic of New Jersey (fig. 19) exceeds the National Map Accuracy Standards for planimetric maps at a scale of 1:5,000,000. The unique process used in making this mosaic is the combination of a common lithographic technique of double printing one or more halftone images on a single sheet of film, giving tone matching, and the image-matching and ground-control techniques of classical mosaicing. The New Jersey mosaic is made of parts of three ERTS images and has two join lines. Because the density range of film is greater than that of paper, every copying operation results in resolution degradation. Therefore, film mosaics of each spectral band were used_to prepare the lithographic plates. This mini- mized the loss of spatial detail and maximized the information in the final printed product. Four plates were used: a black plate containing the grid and all border information and the three color plates—one for band 4 printed in yellow, one for band 5 printed in magenta, and one for band 7 printed in cyan. Band 5 was selected as the master plate because of the greater ease of identification andmeasurement of the ground control points of known loca- tions which ensures geometric accuracy. All 12 frames (three images of four bands each) were enlarged to final scale of 1:500,000, as positives, with careful attention given to obtaining a uniform tone match. A contact negative was made of the center image, and the north and south images were processed to 26 1, Applications to Cartography 27 UNITED STATES NASA ERTS—I DEPARTMENT or THE INTERIOR NEW JERSEY sATELLn-E IMAGE MOSAIC GEOLOGICAL SURVEY sf: ‘y I ‘ _..«,J¢m . w m m an In w w u x In "'30 mun“: my mum» u m u s gramme“ mm I. swam». 'va m «Anon» alumnus m I-muv cam-a: suns Amimsuman m..- Imm m. hm .Mwmm. Wm. st ly m, mnl ozsmmu -.-—- um... I m m: I»: ll : Mum wmu. nuvonmxaw mu mg: M :5 ”Mann: on urn n-Imzlun an I.» Amu‘mvv a! mu mun m...“ I... m. ... I! am... my I . mm m I... mm...- m. M. «W mun u... NEW JERSEY SATELLITE IMAGE MOSAIC I972 FIGURE 19.-—Co|or composite ERTS—1 orthoimage mosaic of New Jersey (part of 1079—15124, 1079—15131, and part of 1079—15133). 28 . ERTS—1, A New Window on Our Planet maintain the same tone in the 10 percent' overlap parts of the images, allow- ing‘ a very accurate spatial junction between images. This use of a positive- negative combination permits accurate registration, because a perfectly regis- tered pair appears as an even gray tone on a light table and misregistrations of 0.01 mm are readily apparent. The three images registered by this process were secured to a Mylar base sheet‘and were pin registered. Pin registration consists of punching holes through the multiple sheets so that when a pin is inserted into the holes the sheets are forced into the correct relative positions. This process insures that, in the creation of photomosaics and in all subsequent printing operations, true image relationships are preserved. , Two photographic masks were prepared and pin registered to the master base sheet. Onemask outlined the area of the center image to be printed and obscured the north and south images. Theother mask covered the center image and permitted the exposure of the north and south images. The dimensions of the windows in the maSks were accurately controlled to permit slight double printing at the join lines between. images, thus obscuring the join lines. , _ The master negatives were secured to their respective masks while both , V .the negatives and maskslwere pin. registered to the base sheet. The two assem- "blies_'(center image and mask and» north and south images and mask) Were .7 then sequentially printed on a: single piece-0f film using pin registration. This process yielded a master mosaic of band'5 of the entire State. ' ' ‘The'images for. bands 4 and 7 were image registered to this master mosaic, ,pin registered to the photomasks, and then were double printed on single ‘ sheets of film, giving three mosaics, one fOr each band, with the entire State “ in perfect registry. These master transparencies Were halftoned and litho- graphed by normal techniques- , I , Identifiable control points of known position were measured on the band ' 5.,mas‘ter transparency, and a- UTM grid was’computed to yield a best fit to the _. identified ground control points. This grid was inCOrporated in the black ' printing plate and was overprinted on the color images in the normal litho- ' graphic four-color sequence, thereby ensuring accurate tone information and ' dimensiOHal control. Thel‘result of this hybrid process is a color lithographic mosaic that exceeds the National Map Accuracy Standards when referenced to the grid. . i _ Thiswas the first time that this process was applied to ERTS imagery. A mosaic of the State of Florida has recently been prepared using this technique and cOntains parts of at least 17 ERTS images. SATELLITE IMAGE MAPS OF THE STATE OF ARIZONA AND OF PHOENIX By Joseph T. PiIonero, US. Geological Survey projection at 1 :1,000,000 scale. It is the first black and white State map of ERTS imagery precisely related to the figure of the Earth (the geoid) and is presently for public sale at scales of 1 :1,000,000 and 1 :500,000. The entire map comprises the 24 ERTS images that are diagramed and listed at the bottom of the sheet. The imagery is from band 6, wholly in the near-infrared. The original photographic source product for the map con- sisted of third-generation film positives, 18.5X18.5 cm at 1 :1,000,000. Photographic processing of individual scenes entailed making intermedi- ate contact negatives from the film positives on a LogEtronic printer, then making X 2 enlarged prints at 1:500,000 on stable paper. The scale was established by reference to the recently compiled 1:500,000—scale Arizona State base (line) map. In mosaicing, individual prints were trimmed inside the borders, and the join edges were feathered to insure smooth, nearly imperceptible joins. The joins were made mostly along streams and dry washes. A wax adhesive was used for mounting the prints to the mosaic board, and a stable copy of the Arizona State base map was used to maintain posi- tional accuracy. Compliance with the horizontal requirement of the National Map Accuracy Standards, as determined from fitting a UTM grid, has been achieved for the 1 :1,000,000 mosaic but not for the 1:500,000 mosaic. The Phoenix satellite image map (fig. 21) is a photoimage map pro— duced from ERTS—l imagery. The map scale of 1:250,000 is at present the largest scale at which the current photographic imagery from ERTS-type satellites is aesthetically acceptable. The map is a mosaic of five images from band 6 enlarged to 121,000,000 and furnished as third-generation film positives. A LogEtronic printer was used to make intermediate contact negatives, and stable-paper prints en- larged to 1 :250,000 were used for the actual mosaicing. In this specific case the map meets the horizontal requirement of the National Map Accuracy Standards, as determined from the UTM grid. The Arizona satellite image map (fig. 20) is a Lambert conformal conic 29 30 ERTS—1, A New Window on Our Planet UNITED STATES DEPARTMENT or THE INTERIOR GEOLOGICAL SURVEY ARIZONA ASA ERTS-I N SATELLITE IMAGE MAP u:- m. 7. r yr L mum m win-Mn .v wt Al . “mm wAva I. Donn-Arum mm nu: “mm: (”was m, sum Anmmxvnfiomuvm "mom 5. am mm GWEN“ wank .vmsmm “mun mauum mm luau w . .., ., .. w hum-m- .... mum-1 mun m‘wummuvmnm-uw. .. . . N w .. . W n m M *m A: . - my m. “I.” Imm mm...“ .mm. mum" w...“ m... m w: u u . quLoaIm mm. n5~vu,mwuoo lam aA mmmmnm. um ,, ARIZONA sum”: was my . |_ 1:724:73 FIGURE 20.—ERTS—1 image map of Arizona. 1, Applications to Cartography 31 mm m nrrnm n or I ”-105le UMVN .— FIGURE 21 .—ERTS—1 image map of Phoenix, Ariz. DIGITAL COLOR MOSAIC OF PARTS OF WYOMING AND MONTANA By Grover Torbert, Bureau of Land Management, and C. J. Robinove, US. Geological Survey digital precision processed mosaic (fig. 22) of eight ERTS images, A taken on July 30 and 31, 1973, was produced by IBM for the Bureau of Land Management. The mosaic depicts parts of eastern Wyoming and eastern Montana where some coal strip mines now exist and where exten- sive coal stripping is expected in the future. The area includes part of the northern Great Plains in Montana and the Fort Peck Reservoir along the Missouri River. To the south is the Yellowstone River, and to the south of that river is the Powder River Basin where a large reserve of mineable coal exists. The Bighorn Basin of Wyoming, bounded by the Bighorn Mountains to the east, is well portrayed in the mosaic; areas of extremely high reflect- ance are desert, and the irrigated crop land along the river valleys shows in dark contrast. At the southern end of the mosaic is the Wind River Basin, including the Riverton irrigation project. Digital processing provides corrected images having a geometric accuracy of approximately one pixel, and, by controlling the images with geodetic control points, the resulting images can be made to meet the National Map Accuracy Standards. Ralph Bernstein (1974) of IBM, who produced the mosaic, states that the computer can combine the input images Without picture-element overlap or space, geometric corrections can be applied to correct the images so that the fit in the overlapped regions is nearly perfect, and nonlinear intensity corrections can be made to the image to provide radiometric matching between images. The original mosaic, as supplied by IBM, is at a scale of 1 :1,000,000- and contains the UTM grid. Processing and mosaicing of ERTS images in this form provide a highly usable base map for terrain and water studies, greatly aid in the multispectral classification of terrain features, and also aid in detecting such temporal changes in the terrain as those produced by strip mining and by strip-mine rehabilitation. FIGURE 22.—Annotated computer-processed color composite ERTS—1 mosaic of parts of Wyoming and Mon- D tana (1372—17225, 1372—1 7231, 1372—17234, 1372—17240, 1373—17283, 1373—17290, 1373—17292, and 32 1373—17295). FORT P‘scxk RESERVOIR. . 40 MILES 30 20 kéPROXIMATE SCALE 10 0 m. E a M m K 0 4 w m o 1 0 0 1 GEODETIC CONTROL IN POLAR REGIONS FOR ACCURATE MAPPING WITH ERTS IMAGERY By William R. MacDonald, US. Geological Survey FIGURE 23'.—McMurdo Sound region, Antarctica. Image at right shows locations of geodetic control stations used to construct the fitted grid for the satellite image at the left (1174—19433, band 7). unn'm suns sum me: scum am or 71-13 mm 1mm cmwclcu. smmzv MC MURDO SOUND REGION, ANTARCTICA mini: 1‘ s. o \ 5 x «s. s ‘ t «‘ 4‘ A x e m a... - _ n. - .u. .' .. I / O ‘ 1 i .. j .. 5. n. —ur— .— 4 «s. I ~.. 4 s a“. t 4‘ s 4’ a / (4 a o h. 6 u. c s I u VIDA-ED um mumuw Iv In: u s amp-sou sir-nu SCALE 1mm m mm». m m. um... “mm m. 5m wmmuvnon .. mm m. u: m. .. . .. . ........ LT... "133;” 1.53:, .gn"”'”"‘" "I“ ”m m o m n n .1 - n n...- _.nmmmw._n.~.—m._m._. .. _ "'"“““""“"'""‘““’“°"‘" ‘¥ ° ” ”fl" MCMURDO SOUND REGION '22:: 3.» .WW :mum :22 a" ”“3332 u.mm.—...mmmm.mmm. 1m ecause geodetic control in the polar regions is very limited and extremely expensive and difficult to establish, it was necessary to find an economical means of acquiring the amount of control needed to maintain the in— tegrity of ERTS cartographic products. In Antarctica the U.S. Geological Survey investigated the practicality of using recently developed Doppler positioning and navigation systems for establishing the much-needed control. The mode tested was the single—point positioning method, which consists of a receiver tracking a satellite pass and computing the position from the Doppler shift and the satellite ephemeris. The experiments proved that Doppler-equipped polar—orbiting satellites can be used as surveying tools and that mapping control can be obtained under Antarctic field conditions. As a result of the Doppler positioning experiments, it is now possible to make maximum cartographic use of ERTS imagery in polar regions by deploying specially equipped teams of topographic engineers to establish ERTS ground control. Positions obtained during the Doppler positioning experiments were used along with existing control to fit a grid to a single image (fig. 23) of the McMurdo Sound region, Antarctica. FIGURE 23.—Continued. EXPLANATION A Geodetic control (Standard surveying methods) A Geodetic control (Derived from Doppler satellite data) 36 ERTS—1, A New Window on Our Planet The technique of converting an ERTS image into a cartographic product by following the grid rather than the image rectification appears to be the most practical and cost—effective way of relating/polar ERTS-image data to the Earth’s surface. Normally the procedure is to modify the photoimage through tilt analysis and rectification to fit a grid. \Vhen applying these pro— cedures to ERTS imagery, however, geometry is improved, but too much detail (resolution) is lost during the photographic processes. Four steps are required to fit a grid to an ERTS image: 1. Identification of discrete image points for which coordinates are known. 2. Accurate measurement of the m and 3/ values of these control points on the image scene. 3. Determination of the transformation parameters to relate one system to the other, and computation of the intersection of the grid lines in an image coordinate system, warping the grid to fit the image. 4. Plotting the grid on an overlay keyed to the image. The accuracy of image identification of the control points is the primary element that determines the accuracy of the grid fit. In the mid-latitudes, where large-scale accurate maps are available, good results can be obtained by using images of timber corners, fence lines, centers of bridges over streams, pipe and powerline crossings, and so on, as control points. In these areas, in most cases, the grid can be fitted to the image so that the image product meets the National Map Accuracy Standards at scales of 1:500,000 and smaller. In the poorly mapped polar regions, especially in Antarctica for which good maps and where control are scarce, there is less certainty in the selection of points used in the gridding process. Therefore, the resulting grid fit may not meet the National Map Accuracy Standards, which require that 90 percent of all well-defined planimetric detail fall within 0.5 mm of correct map position at 1 : 500,000 scale. The grid fit to the McMurdo Sound image (fig. 23) using 13 triangula- tion points gave rms error of 183 In, or only about 10 in over accuracy stan- dards. However, if discrete points had been preselected on the imagery and if the ground positions for these points had been established by the Doppler field techniques previously described, it is reasonable to believe that the National Map Accuracy Standards could be met at 1 2500,000 scale and smaller. ANTARCTIC CARTOGRAPHY By William R. MacDonald, US. Geological Survey or the preparation of maps in support of the US. Antarctic Research F Program, the United States has obtained aerial photography over an area of about 3,250,000 kmz. This effort has taken many years and has cost many millions of dollars. ERTS—l now provides the capability of pro— ducing a single image covering an area of about 34,000 km2 (185 by 185 km). About 100 ERTS images would cover the same area now covered by more than 100,000 aerial photographs. An important current objective is the compilation of 121,000,000 image mosaics of the coastal areas of western Antarctica and, eventually, of all the coastal areas of Antarctica. These image mosaic products will enable the US. Geological Survey to build a historical record which, when compared against existing maps and sequential ERTS coverage, will show changes in size, shape, and position of such features as ice shelves, glaciers, and ice tongues. Further investigations have proved that ERTS imagery can be used ef- fectively for planimetric revision of small-scale maps, and this technique is being applied to six 1:250,000 topographic maps of the area of the Victoria Land strip mosaic. The coastline shown on the images was carefully com- pared with existing maps, and several major changes in coastal features were discovered. The comparison showed that the new satellite imagery can great— ly facilitate accurate planimetric revision of the existing maps (figs. 24, 25). Figure 26 illustrates the application of ERT S imagery for evaluating and revising published maps. The bottom part is a composite of two 1:500,000 sketch maps compiled from conventional aerial photographs taken during the austral summer of 1965—66. The top part is a mosaic of parts of seven MSS images. The area shown is about 117,000 kmz. The two triangles represent geodetic positions used to fit the imagery mosaic to the map base. A single ERTS image covers the same area as 1,320 photographs at a scale of 1:40,000. When comparing the two parts of figure 26, note the change in the configuration of the coast, as indicated by numbers 1, 3, and 4, and in the position of Burke Island, number 2. Also note the change in size and position of the Thwaites Iceberg Tongue, number 5. Its area has increased from 44,200 km2 (map) to 71,500 km2 (image), and the position has shifted about 8 km. Because of the logistical requirements and the extremely high cost of taking photographs with conventional aircraft at altitudes high enough for efficient 1:1,000,000 mapping, efforts before the launching of ERTS—l were directed primarily toward mapping the coastal and mountain areas at 1:250,000. ERTS imagery does, however, meet the need for 111,000,000 plani- metric mapping. To cover an IMW map area, cartographers will only have to assemble 15 to 20 ERTS images rather than 12,000 conventional photo- 37 38 ERTS—1, A New Window on Our Planet graphs. Production cost will decrease as production rate increases. The user will have at his disposal a visual representation of vast areas that have never been mapped. Moreover, he will not have to wait years before the image maps are available as he would for conventional planimetric or topographic maps. COmparisons of image mosaics with the USGS—compiled McMurdo Sound region, IMW sheet ST 57—60 (fig. 27), and with the Australian-compiled IMW sheet, SS 40—42 (fig. 28), clearly demonstrate the application. Revisions and additions indicated for the two IMW sheets are readily apparent. The most obvious addition is the large block of previously unmapped geographi- cal features revealed by the ERTS imagery. Noteworthy revisions include correcting the positions of the Ross Ice Shelf front (about 6.4 km north) and Franklin Island (7.2 km south). The position of Franklin Island has been in ,7 75° 76° S 164°E 166°E APPROXIMATE SCALE 10 0 10 20 3o 4OM|LES 1'0 0 10 20 30 4O KILOMETERS FIGURE 24,—Drygalski Ice Tongue, Victoria Land coast area of Antarctica. At left is a mosaic of three 1:250,000 US. Geological Survey topographic maps compiled from source data, 1955-64. Annotated revisions are based on the ERTS—1 image mosaic shown at right. Significant changes are: A, Harbord Glacier,- B, Drygalski Ice Tongue; and C, fast ice (1128—20290, 1128—20293, 1163—20224, 1163—20230, and 1177—20001; all band 7). 1, Applications to Cartography 39 contention for many years and has been continually reported to be wrong by ships. ERTS imagery promises to be highly cost effective and of great scientific benefit to research on Antarctica, the most remote region on Earth. As a cartographic tool, ERTS offers the most practical means available to obtain cloud-free imagery of the millions of square kilometers of the continent still unmapped and to monitor coastal glaciological features (Southard and Mac- Donald, 1973). In summary, these experiments underway with ERTS—l imagery of Antarctica have already demonstrated the feasibility of (1) planimetric re- vision of available small-scale maps, (2) detection of gross changes in the northern limits of the three largest ice shelves in the world, (3) monitoring coastal glaciers,and (4) exposing hitherto unknown geographic features. 74°S 170°E 171°E APPROXIMATE SCALE 10 0 10 20 30 40 MILES 10 0 10 20 30 4O KILOMETERS FIGURE 25.——Cape Adare, Victoria Land coast area of Antarctica. At left is a mosaic of three 1:250,000 U.S. Geo- logical Survey topographic maps from source data, 1961—64. Annotated revisions are based on the ERTS—1 image mosaic shown at right. Significant changes are: C, boundary of fast ice and bay ice has changed, and D, shape of Honeycomb and lronside Glaciers has changed, and their tongues have advanced about 3.2 km (1128—20275, 1128—20281, and 1128—20284; all band 7). 40 ERTS—1, A New Window on Our Planet nu mu 2°w 11o°w 108°W 114°W 11 “A s\';\\\\73.° S‘ / ' < 'I. , .0 9 A ' 7‘ ‘ ' +12le v 4\ .1.» 10 0 10 20 3O 4O 50MILES 1b 0 10 20 30 4O 50 KlLOMETERS FIGURE 26.—Thwaites Iceberg Tongue, Amundsen Sea area of Antarctica. Comparison of the annotated mosaic of ERTS-1 image mosaic (top) and the corresponding sketch map (below) shows significant changes of the coastline and position changes of map features made by using ERTS imagery. Geodetic control points are shown at A and B (1137—14265, 1137—14271, 1157—14374, 1157—14380, 1157—14383, 1160—14551, and 1160—14554; all band 7). 1, Applications to Cartography 41 7 SKEUON GLACIER APPROXIMATE SCALE 50 0 50 100 MILES I l I I 1 l I I F1 ' ' ' I I I 50 O 50 100 KILOMETERS FIGURE 27.—McMurdo Sound region of Antarctica, 1:1,000,000 map (IMW Series, ST 57—60) compared with annotated ERTS—1 image mosaic. With the aid of the mosaic, newly discovered mountains, other land features, and coastline cor- rections will be added to a new U.S. Geological Survey 1:1,000,000-scale manuscript map before it is published (1128—20290, 1128—20293, 1143—20124, 1151—19151, 1154—19322, 1163—20230, 1165-18520, 1165-18523, 1174—19431, 1174—19433, 1177—20001, 1191—19383, and 1194—19555; all band 7). 42 ERTS—1, A New Window on Our Planet \ t j ' APPROXIMATE SCALE \ \_ _ l 0 50 100 MILES i‘ l I l I | J I mar—L“. IIIIIT l I 760:0" E 64° E 50 0 50 100 KlLOMETERS FIGURE 28.—Australian 1:1,000,000 map (lMW Series, SS 40—42) of the Lambert Glacier area of Antarctica compared with an an- notated ERTS—‘l image mosaic. With the aid of the mosaic, existing source maps can be analyzed and evaluated. The imagery reveals previously unknown mountains and other significant land features that can be added to a revision of this map (1145— 03101, 1148—03261, 1148—03263, 1148—03270, 1168—03374, 1168—03381, 1196—02521, 1196—02523, and 1196—02530; all band 7). 1. Applications to Cartography 43 If we are to have a better understanding of the way the polar regions afi'ect man, particularly in assessing the potential resources of Antarctica, there is an immediate need to know What’s there and Where. Space technology offers a new method for producing small-scale imagery products of remote regions that is substantially cheaper and quicker than production by conven- tional means. The reasons for this are: Advantages of E HTS synoptic coverage .' P‘PWF’!‘ 6. Current, complete, and repetitive imaging. First-look imagery of unmapped areas. Weather conditions not dominant. Fewer exposures and greater areal coverage per image. Reduced compilation cost for small—scale products (for example, 1 1,000,000). Single scene and synoptic views. Special uses and benefits .' 1. 2. 3. 4. Time-lapse sequence of images for thematic mapping: coastal change 9.0! Source for medium- and small-scale orthoimage products. Source for medium— and small—scale planimetric-map revision. Source for orthoimage mosaics. detection, sea-ice studies, ice-movement studies, and so forth. Planning document. Visual navigational aids (near-real time). CADASTRAL BOUNDARIES ON ERTS IMAGES By Grover Torbert, Bureau of Land Management, and William R. Hemphill, US. Geological Survey he ERTS—l CCT’s permit combining a part of the image of the Sheridan T area of ‘Wyoming (fig. 29) with a cadastral—survey delineation of town— ship, range, and section boundaries. The combination of image and cadastral map (fig. 30) shows 939 km2 of Sheridan and Big Horn Counties in Wyoming and Montana, respectively. Standard US. Geological Survey quad- rangle maps of the area are shown in figure 31 for comparison. The cadastral data, together with four selected ground control points recognized in the ERTS image, were digitized from written descriptions and existing maps and combined with the ERTS—l CCT in a PDP 11/45 com- puter. The combination of image and cadastral delineation was printed With a Calcomp plotter Model 728 flatbed. The gray scale of each pixel is repre- sented by varying the amount of ink distributed to each dot. Cadastral bound- aries, roads, and streams are represented by plotting one-third the normal pixel area. The Tongue River flows eastward and northward in the central and northeastern parts of the image map, respectively. The foothills of the Big- horn Mountains can be seen in the southwest corner. Dark-toned circular pat- terns in the west—central part are radial irrigation systems. This image map was produced by Computer Research Corp., Arvada, Colo., for the Bureau of Land Management to use for recording changes in land ownership and land use on a pictorial base. Such a base can be used to relate land ownership to seasonal change in grassland areas as a guide to the release or withdrawal of grazing leases on public lands administered by the bureau. The image map will also facilitate interaction with a computer- implemented land-information system that is being designed. The bureau is especially interested in this area because of the marked increase in coal strip mining that has occurred since 1972. 44 1, Applications to Cartography mas-3m mods-an ”NBS-GB ”NBS-38 SO I 0112182 I '90.) ' METER! I DU U ULDQZ “Sat? 1 UV D's)? N e 6 6 may I (“Gav-F? I H187‘BBI “166-30! ea NIB ' 1 23152 C MS-BS/HIOS-QS N N45-87/N186-Bl "SS '5 D SUN EL“ 4|8-G-i‘N-D-ZL NHSFI ERTS 915633472335 8! APPROXIMATE SCALE 10 20 30 MILES 30 KILOMETERS FIGURE 29.—Ann0tated color composite ERTS—1' image of the Sheridan area of Wyoming (1030—17233). 46 ERTS—1, A New Window on Our Planet 3 ‘07‘00 A QQQ‘V.’ ‘ ‘0‘ > I 39%“ w. V593"? 2 fish? ‘i \v 40,000 FEET 4| 30,000 8000 M ETERS of Wyoming from published 71/2-min quadrangle maps: Ranchester, FIGURE 31.—Standard US. Geological Survey map of the Sheridan area Monarch, Wolf, and Hultz Draw. 20,000 I I 6000 10,?00 APPROXIMATE SCALE 2000 4000 0 II 'I 0 2000 10,000 ERTS—1 image and the cadastral survey delineation of township, range, and section boundaries (part of 1030—17233, band 4). FIGURE 30.—Computer-processed combination of part of the Sheridan 1, Applications to Cartography 47 REFERENCES Bernstein, Ralph, 1974, Digital image correction and information extraction [abs.]: lnternat. Symposium on Remote Sensing of Environment, 9th, Ann Arbor, Mich., 1974, Proc., v. 2, p. 851—852. Colvocoresses, A. P., 1972, Cartographic,applications of ERTS imagery: NASA Goddard Space Flight Center, Earth Resources Technology Satellite Symposium, Sept. 1972, Proc., p. 88—94. 1973a, Unique characteristics of ERTS: NASA Goddard Space Flight Center, Symposium on Significant Results Obtained from the Earth Resources Technology Satellite—1, 2d, New Carrollton, Md., Mar. 1973, Proc., v. 1, sec. B, p. 1523—1525. 1973b, The ERTS image format as the basis for a map series: Am. Soc. Photogrammetry, Symposium on Management and Utilization of Remote Sensing Data, Sioux Falls, 5. Dak.,1973, Proc., p. 142—143. 1974a, Space Oblique Mercator: Photogramm. Eng, v. 40, no. 8, p. 921—926. 1974b, Towards an operational ERTS—Requirements for implement- ing cartographic applications of an operational ERTS—type satellite: NASA Goddard Space Flight Center, Symposium on the Earth Resources Technology Satellite—1, 3d, Washington, DC, Dec. 1973, Proc., v. 1, sec. A, p. 539—546. Colvocoresses, A. P., and McEwen, R. B., 1973, Progress in cartography, EROS Program: NASA Goddard Space Flight Center, Symposium on Signifi- cant Results Obtained from the Earth Resources Technology Satellite—1, 2d, New Carrollton, Md., Mar. 1973, Proc., v. 1, sec. B, p. 887—898. Southard, R. P., and MacDonald, W. R., 1973, The cartographic and scien- tific application of ERTS—1 imagery in polar regions [abs.]: COSPAR Plenary Mtg., 17th, Konstanz, Germany, 1973, Program Abs., p. 70. Stein, G. E., 1971, Portrayal of earth features with NASA photography, in American Congress on Surveying and Mapping, Papers from the 1971 ASP—ACSM Fall Convention * * *: Washington, DC, Am. Cong. Survey- ing and Mapping, p. 308—314. [Sample chart areas, NASA photos, and revised samples are available under separate cover from: Aeronautical Chart and Information Center, Cartography Division, 2d and Arsenal Sts., St. Louis, Mo. 63118.] CHAPTER 2. APPLICATIONS TO GEOLOGY AND GEOPHYSICS INTRODUCTION By William A. Fischer, US. Geological Survey land. This knowledge provides an understanding of geologic hazards— such as landslides, earthquakes, volcanic eruptions, and land subsidence ——as well as the engineering properties of soils and rocks. In addition, such knowledge aids in pinpointing potential sources of minerals and fuels. ERT S has permitted geologists to rapidly expand their geologic knowledge by revealing features that were never before recognized and that are worthy of investigative priority. Furthermore, ERTS has provided geologists and other scientists throughout the world with a common set of data, so that communi— cation in the profession is vastly improved and progress toward geologic understanding is accelerated. This chapter is one of the largest in this book and reflects geologists’ long history of using aerial photography and their seemingly inherent desire to always View the study area from the “highest hill.” The broad involvement of geologists and their willingness to contribute to this work are testimony to the geologic values inherent in the ERTS data. Papers in this chapter primarily deal with the use of imagery, but the use of the ERTS data collection system to collect information from ground sen- sors located in remote areas is also described. Collectively, the papers present a cross section of preliminary results gleaned from satellite data. Although ERTS was designed for a variety of scientific purposes, a series of geologic hypotheses that were advanced played a major role in determining the final design criteria. These hypotheses were: 1. That large features (including glacial features, faults and other linea- ments, and volcanic features) are present on the surface of the Earth that, because of their size and subtle expression, had gone unrecognized in conventional ground and aerial surveys but that can be seen on images having suflicient areal coverage and spectral uniformity. 2. That color or multispectral images properly recorded and processed to preserve color uniformity would be useful in mapping distributions of rock types and alteration products. 3. That some environmental features are only intermittently visible depend- ing on angle of illuminatiton and on snow, water, or vegetation dis- tributions. Geologic knowledge is essential for determining the optimum use of our 48 2_ Applications to Geology and Geophysics 49 4. That some geologic processes, such as sedimentation and glacial motion, could be better understood if viewed in a “time—lapse” mode. The need to test these hypotheses was a significant factor in the decisions that led to adoption of the repetitive, time-uniform, multispectral character and narrow-angle field of view of the ERT S system. All the papers in this chapter support one or more of these hypotheses. Most present results that have relatively short—term economic significance in that they provide information that will add to the efficiency of exploration for minerals, fuels, and ground water. Some, such as Brown and Huifman’s study of the Jordan Rift Valley (p. 53), have immediate scientific impact but are of longer range economic significance. Most papers in the section deal with the mapping of large previously unknown geologic structures—principally linea— ments and faults—that may constitute geologic hazards or that may control localization of mineral deposits, suspected folds that may be oil bearing, and glacial features that may be sources of large quantities of ground water. Morrison’s paper (p. 7 2) on the enhanced visibility of snow—covered ter— rain features provides good examples of geologic features that are only inter- mittently visible. Further documentation of the advantages of the multi— spectral approach to viewing the Earth is given by Schmidt, who discusses the detection of hydrothermal sulfide deposits in the Saindak area of western Pakistan (p. 89) and by Stoertz and Carter (p. 76) in citing the conclusion of Dr. Brockmann of Bolivia that color adds 40 to 50 percent. more to the geologic information that can be interpreted from a given ERTS image. Full use of the multispectral qualities of ERTS, however, requires that the inter- pretations be made using the digital magnetic tapes (CCT’S) of the data instead of the analog images. These tapes preserve the spectral qualities of the data to a larger extent than do photographs and permit the various bands to be compared or ratioed, as in the case of the study by Rowan, “Vetlaufer, and Goetz (p. 102). The articles dealing with foreign areas indicate the tremendous amount. of geologic information that is being derived from the relatively straightforward use of ERTS data to improve the world cartographic base maps; Stoertz and Carter (p. 76) point out that of 150 salars (salt-encrusted—basins) in parts of Chile, Bolivia, Argentina, and Peru, 20 were unmapped before ERTS. The new classification system for the desert sand seas developed by McKee and Breed (p. 81) is illustrative of the value of uniform global coverage; the" long-range value of their work for improving geologic communication and education will be great. The deployment of seismic—event counters and other sensors 011 15 vol— canoes, the successful relay of measurements via the ERTS satellite, and the receipt of “telltale” warning signals from Volcan Fuego in Guatemala 5 days before eruption clearly demonstrate the technological and economic feasibility of building a global volcano—surveillance system (see \Vard and Eaton, p. 106). I believe that the reports in this chapter demonstrate that geologists, having tested ERTS as a new working tool, have not found it wanting. GEOLOGIC ANALYSIS OF THE SANTA LUCIA RANGE, CALIFORNIA By Donald C. Ross, U.S. Geological Survey eologic interpretation of the granitic and metamorphic basement of the G Santa Lucia Range is hindered by structural complexity, dense vegeta- tion cover, and a lack of distinctive mappable units. Evidence for fault- ing is common and Widespread, but the distinction of through-going zones that may distinguish major movement from local minor faults is diflicult to make. A northwest-trending group of lineaments is visible on 1 : 1,000,000 ERTS imagery of the area (figs. 32 and 33). Most of the better displayed lineaments are unusually straight segments of stream courses that combine to form rela- tively continuous linear features tens of kilometers long. Many of these straight stream courses have been interpreted and mapped as faults by earlier workers. Interpretation of orbital imagery (fig. 33) takes into account most of the previously mapped fault segments and suggests an overall simpler and more continuous pattern of faulting than earlier published interpretations of this basement block (Jennings and Strand, 1958). The interpretation points to an anastamosing fault system that cuts completely through the Santa Lucia Range basement block. Other evidence suggests that the easternmost faults of this system do not noticeably disturb the basement (displacements are on the order of a few thousand feet), Whereas the westernmost “solid—line” fault juxtaposes some very different rocks and may reflect a major basement offset. The relatively continuous nearly 50-km lineament at A, which may reflect this fault, certainly supports the hypothesis that this is a major basement break. 50 locum—z 2, Applications to Geology and Geophysics 51 cum-ea "ml-3| HIZl-Ul WEB-3| ' I ' W‘ ' 2 ' a 2 25.1“.” C N35'52/Nl2l'24 NW—ngZI-ZI lfi 5 n Mflglm 191;“- ‘I'N'D'ZL ; ' ”"lSIQ'S m p APPROXIMATE SCALE 0 10 20 30 MILES l I l | | | | l ' ' ' ' l l l l 10 O 10 20 30 KILOMETERS 10 II FIGURE 32.——Color composite ERTS-1 image of the Salinas Valley and the Santa Lucia Range, Calif. (1002—18140). I DO I (”(902 IOU I 010002 I DO I 0|sz 52 ERTS—1, A New Window on Our Planet Monterey Peninsula SOLID LINES Anastumosing fault system in pan based on photo-lineaments DASHED LINES Other faults in basement block DOTTED LINES Outline of granitic and metamorphic basement APPROXIMATE SCALE 10 0 10 20 30 MILES I I I l | l I l | I I I I l l I I 10 0 IO 20 30 KILOMETERS FIGURE 33.—ERTS—1 image showing interpretation of photolineaments in the northern Santa Lucia Range, Calif. (1002—18140). Letter A indicates continuous 50-km lineament. AN INTERPRETATION OF THE JORDAN RIFT VALLEY By G. F. Brown and A. C. Huffman, ‘ US. Geological Survey i mong the more discernible features on ERTS imagery are the large A linear features associated with faulting along rift valleys. Of these the opening of the Red Sea and the Gulf of Aden have received widespread att ntion (Girdler, 1962; Le Pichon and Heirtzler, 1968; and McKenzie and 0th rs, 1970). Following Euler’s fixed—axis theorem for the nature of plate mo ‘ement (that is, that relative movement of any segment of the globe with regard to another segment requires rotation around a pole through the center of a sphere), the openings of the Red Sea and the Gulf of Aden (fig. 34:, R and A, respectively) require at least two poles. Also, as seems likely, Gulf spread- ing, began earlier along transform faults with meridional shearing along the Re Sea rift. Using azimuths to transform faults and fault-plane solutions fro first—motion studies, Girdler (1972) has postulated the location of two pol s of rotation. For the Gulf of Aden (Arabian—Somalian plates) he favors McKenzie’s position of lat 26°30’N.; long 21°30’E., and for the Red Sea (Arabian-Nubian plates) he favors a location at lat 31°30’N.; long 23°00’E. (fijg. 34). A The Jordan Rift Valley is a striking example of the large linear features, an , if Girdler’s pole locations and two periods of rapid separative movement are accepted, we would expect to see a difference in bearing of the Jordan rift north of its junction with the Red Sea. Examination of the latest geologic m 1ps of the Levant does show a bearing of about N. 10° E. for the earlier op ning, swinging to a meridional trend toward Lebanon from the pole of lat 26°30’N.; long 21°30’E., where a fault zone appears to swing into the M diterranean Sea between Beirut and Tyre; an examination of a mosaic of TS images (fig. 85) confirms this bearing. Indeed, the European geologic in p (von Gaertner and \Valther, 1971) shows the northeast-trending Carmel fa ilt (Freund, 1970, fig. 1) extending into the Mediterranean Sea at Haifa, so e kilometers farther south, which fits a rotation around the southernmost p0 e even better. As would be expected, the older fault zone is more obscure, even though the lineament is well-defined 0n the ERTS imagery. Inspection of,this feature along the Beirut-Tyre road in southern Lebanon reveals exten- StF disturbance that approaches a crushed—zone appearance. North of Beirut, th younger, more pronounced faults trend north—northeast, in keeping with a p le location farther north than the location of the Gulf of Aden pole. Earlier l 53 54 ERTS—1, A New Window on Our Planet locations by McKenzie and others (1970) at lat 36°30’N.; long 18°00’E., West of Greece in the Mediterranean Sea, fit the bearing of the faults north of Beirut as well as the transverse fault between Masirah Island and Oman in the southeastern shore of the Arabian Peninsula. Thus, in this example, ERTS imagery tends to clarify and confirm one interpretation for the history of the Red Sea and the Gulf of Aden. 20' 40° 50‘ 60° ’BEIRUT ’ I 20° 500 MILES O 500 KILOMETERS m. I | i I Figure 34.——Map of the Red Sea area showing location of tectonic-plate rotation poles. IWIMZ locum: MIMI [WINWZ lam - Nuaz Ismia-m-aa N M67 m 4 R S. Rum lQ-W-G-l- III-2|. Wé-IW-O7fll2 BI 155972 c Mas-33403641 u yea-m4. ms 4 R sun as man m-o‘m-G-I- 0-2. mm ms E-1054-074IS 9: FIGURE 35.——Annotated color composite ERTS—1 image mosaic of the Jordan Rift Valley (1054—07412 and 1054—07415). 00 . mum. INA hUDZ ICOI m2 IOU-Wm GEOLOGICAL STRUCTURE IN THE WESTERN BROOKS RANGE AREA By Ernest H. Lathram, US. Geological Survey espite several seasons of exploration by private companies and by the D US. Geological Survey, the ubiquitous tundra cover and the paucity of outcrops along the shallow streams and rivers in the lowland area of the Ipewik and Kukpuk Rivers have prevented recognition of the distribution of structural elements. Examination of conventional aerial photographs has revealed little additional data. This ERTS image (fig. 36), however, displays a startlingly clear and detailed representation of the area (Lathram, 1973). The image shows clearly the complexity of structure in the lowland and the pronounced difference between the structural pattern in this area and that in the areas of strata of comparable age (to the north and east) and of older strata in the mountains (to the south and east) (fig. 37 ). The change to greater structural complexity in the lowlands may be due to oroclinal bending around an axis trending northwest through the lowlands (Tailleur and Brosgé, 1970) or, more probably, due to the superimposition of a younger belt of east— directed thrust faults in the western part of the area upon an older belt of north-directed thrust faults in the Brooks Range (Grantz and others, 1970). Recognition of the structural complexity and determination of its cause are critically important in determining the potential for petroleum accumulations at depth in the area (Lathram and others, 1973). 56 2_ Applications to Geology and Geophysics 57 HISI -88| DO ' —O—l: I low I 40302 H l 6 2 B B INISG- mes-ea HI - mm C fi-B‘Mfllfl-Zl N BBS- ‘ I. ‘ ZM-OIZB-fi-l-N-D-ZL MSFI Widow-22390 Bl APPROXIMATE SCALE 10 20 30 MIL ES 10 20 30 KILOMETERS FIGURE 36.—Color composite ERTS—1 image of the western Brooks Range area of Alaska (1009-22090). 58 ERTS—1, A New Window on Our Planet 2 OPEN FGtDS V ' .‘MAHC AND ULTRAMAFIC BODIES APPROXIMATE SCALE 0 10 20 30MILE$ I l l l 1 l l l J O l l 10 20 30 KILOMETERS FIGURE 37.—Annotated ERTS-1 image of the western Brooks Range area of Alaska, showing geologic features and place names (1009—22090, band 7). GEOLOGICAL EVALUATION OF NORTH-CENTRAL ARIZONA By Donald P. Elston, U.S. Geological Survey essed by the Jet Propulsion Laboratory, Pasadena, Calif., to enhance detail and enlarged to approximately 1:200,000, were analyzed mono- scopically and stereoscopically for their geologic information (Goetz and others, 1973). Figure 38 is a standard ERTS MSS color composite image, and figure 39 is a computer-enhanced nonconventional color composite image of north—central Arizona. The ERTS project test site in north-central Arizona includes areas that have been mapped in detail at 1248,000 and 1:62,500. A large part of the area, however, has only been mapped in reconnaissance at 1:375,000 for the geologic map of Arizona that was published at 1:500,000 (Wilson and others, 1969). A north-central part of the Arizona geologic map is shown in figure 40. Use of the ERTS images, principally bands 6 and ‘7, improves the dis- tribution of several of the geologic units shown on the State geologic map; units shown in figure 41 and the accompanying explanation were discriminated using both the images and detailed geologic maps. The product is a regional geologic map referenced to a near-orthographic image base. Geologic detail, of course, is less than that of large-scale standard geologic quadrangle maps, but it is greater in areas that only have been mapped in reconnaissance. It is es- pecially useful to plot geology on an orthographic image base because relations of geologic units to physiographic, vegetational,‘ and structural characteristics of the terrain can be evaluated from a single display. Transfer of the plani- metric geology to a topographic base allows complementary analysis using standard techniques. Basalt of late Tertiary age crops out in much of the area, and for the most part it was readily discriminated on the ERTS images. Within an area map- ped as basalt on the State geologic map, a light-colored area that proved to be highly tuffaceous was recognized and mapped. Quaternary and Tertiary sedi— ments also were recognized and mapped on the ERTS images,and details of their distribution were better than on the State geologic map. Fine details of the stratigraphy in gray to white Paleozoic rocks (sandstone and limestone) could not be resolved. however, although the red sandstone of the Supai For- mation of Permian and Pennsylvanian age was identified on false—color images. All Paleozoic rocks therefore were mapped as one unit; thus, at least for Paleozoic rocks, the State geologic map is far superior. In contrast, more Pre- l Iigh-quality ERTS—l images of north-central Arizona, computer proc- 59 60 ERTS—1, A New Window on Our Planet MOSS-HI I“! 12-“ H“ l-38l Hill-wl Lina-am Him-eel Irma-39 APPROXIMATE SCALE 10 O 10 20 3OMILES l I l l | I I I I I I I l | I I 10 0 10 20 30 KILOMETERS FIGURE 38.——Annotated color composite ERTS—1 image of north-central Arizona (1337—17325). FIGURE 39.—Computer-processed four-band color composite ERTS—1 image of north-central Arizona. This image has under-v gone a nonlinear (gaussian) computer contrast stretch at the Jet Propulsion Laboratory, Pasadena, Calif. Color units and tone boundaries correlate with stratigraphic and vegetation units. Bronze, mountain and plateau vegetation (mainly Ponderosa pine); yellowish orange, vegetation along stream courses (mainly cottonwood and sycamore trees); greenish tan in north-central part of scene, red beds (red brown) of Supai Formation of Pennsylvanian and Permian age; greenish blue, basaltic flows of late Tertiary (Miocene and Pliocene) age; creamy white, lake beds (siltstone and marl) of late Tertiary Verde Formation (enlargement of part of 1337—17325, fig. 38). on I .5002 I 00 I O——= l 00 I Aw“! low-tom: APPROXIMATE SCALE 0 10 MILES LU‘fiHHT‘T+—|——' 10 0 10 KILOMETERS 62 ERTS—1, A New Window on Our_Planet APPROXIMATE SCALE ‘0 MILES 1 0 KILOMETERS FIGURE 40.—Geologic map of north-central Arizona (from Wilson and others, 1969). 2, Applications to Geology and Geophysics 63 cambrian units could be identified in the ERTS images than are shown on the State geologic map, apparently because of the structural grain and, locally, color; for the older rocks, therefore, the ERTS photogeologic map is an im- provement over the State map. ERTS images at approximately 1:200,000 com- bined with conventional photogeologic and field geologic techniques can thus lead to more efficient reconnaissance geologic mapping and improved recon- naissance maps. The most striking geologic advantage of the ERTS images is their synop- tic view of fracture and lineament patterns that occur in basement rocks and in surficial deposits that mask the bedrock and basement. Faults and linea- ments in north-central Arizona are shown in figure 41. The faults are from published maps. The traces of some faults were less clear than the traces of nearby linear features. Faults are shown as heavy lines on figure 41 merely to differentiate them from the lineaments. The north-central Arizona site lies within the Colorado Plateau province, and only comparatively simple high-angle normal or gravity faults displace the Tertiary and Paleozoic rocks. Thus, where Precambrian rocks are exposed, the structure that is seen is principally of Precambrian age. The dominant Precambrian lineament systems trend north, northeast, and east, with north- and northeast-trending systems strongly developed. Northwest-trending faults and lineaments, which mainly reflect much later structural adjustments that occurred during the Tertiary, are mostly subdued compared to the other systems. A comparison of the geologic and lineament maps shows that the Pre- cambrian structural grain clearly has been imparted to the overlying Phanero- zoic rocks and that the Precambrian lineament systems apparently have been sites of renewed structural adjustments. The north-trending Oak Creek fault in the northeast ( fig. 42) can be seen at the surface to displace only Paleozoic and Tertiary rocks. It very likely reflects a north-trending fracture system in the basement, one that appears en echelon to the Precambrian Shylock fault zone in the south-central part of the map area. Northeast—trending lineament systems also occur in Tertiary and Paleozoic rocks on the Colorado Plateau. N ear lVilliams, Ariz. (near lat 35°15’N.; long 112°12’XV.), eruptive centers of the upper Tertiary San Francisco volcanic field are localized along some of these lineaments. The northeast—trending lineaments presumably reflect an underlying northeast—trending Precambrian fracture system along which re- newed structural adjustments occurred; they are similar in trend to the Chap- arral and Spud faults and associated northeast—trending lineaments in Pre— cambrian terrane in the southern part of the map area. A myriad of fractures and lineaments occur in well-exposed Paleozoic strata in the Sedona area, west of the Oak Creek fault. Northwest-trending fractures in the Sedona area were believed to be dominant until mapping with ERTS images revealed the existence of strongly developed east- and northeast- trending lineaments, the existence of which appears to have been responsible for the development of an erosional embayment in the margin of the Colorado Plateau here. Fracture systems and lineaments in the Sedona area are current- ly being mapped in detail using XASA high-altitude-aircraft photographs, supplemented by field mapping, to provide data for a comparative evaluation of similar data from images obtained from still higher altitudes and orbit (Skylab and ERTS). Lineaments that have been plotted from ERTS images, and those to be plotted from Skylab images, will be compared to the detailed geologic map. 64 ERTS—‘I, A New Window on Our Planet The geologic work in the Sedona area has the practical objective of defin- ing areas structurally favorable for the localization of ground-water resources in an area having a burgeoning population. Anticipated targets for future exploration for ground water are places where ancient concealed karst (lime- stone cavern) ground in the Redwall Limestone of Mississippian age is inter- sected by through-going fracture systems at structurally favorable elevations. EXPLANATION FOR FIGURES 41 AND 42 SEDIMENTARY ROCKS METAMORPHIC ROCKS 3 § Os 8 g Gravel and alluvium T52 S Sandstone and lake beds VOLCANIC ROCKS § 5‘ Ts1 Tvb Tvt Sandstone Tvb, basalt Tvt, tuff .9 8 Eu l N S d t d 1' t , a? K an 5 ”33522016?“ (me IGNEOUS ROCKS p€ms p€qd peg Quartzite Quartz diorite and granite ,§ E E f p€r 8 g Rhyolite 9.4 p€rnsv [:65 ngb Metasedimentary and metavolcanic Gabbro rocks and schist Contact Dashed where approximately located; short dashed where indefinite FAULT AND LINEAMENT MAP _-T—"_-_ ..... Fault From published geologic maps. Bar and ball on downthrown side. Dashed where approximately located; dotted where con— cealed Lineament Long traces reflect strongly developed trends, some of which are inferred to be faults. Intermediate and short dashed lines reflect degree of traceability of individual lineaments; dots reflect an alinement of one or more vague linear features 2, Applications to Geology and Geophysics 65 FIGURE 41.—Geologic map of north-central Arizona compiled on an ERT —1 image base (part of 1337—17325, band 6). Data are from published and unpublished sources. 66 ERTS—1, A New Window on Our Planet 3A'15' FIGURE 42.—Fau|t and lineament map of north-central Arizona compiled on an ERTS~1 image base (part of 1337—17325, band 6). Faults from published information; lineaments interpreted from ERTS images. Explanation is on page 64. GLACIAL GEOLOGY AND SOILS IN THE MIDWESTERN UNITED STATES By Roger B. Morrison, US. Geological Survey in the glaciated Midwestern United States because of low relief, lush vege- tative cover during the growing season, and frequently clouds, haze, and smog. A few images, however, taken under just the right conditions yield, by means of subtle variations in tone, a remarkable amount of information on macroscale geologic and physiographic features that have little topographic expression (Morrison and Hallberg, 197 3). The best time of year for getting images showing the differences between surficial deposits and soils in the Midwest, caused mainly by variations in soil moisture, is middle to late spring after the croplands have been newly plowed and while soil moisture still is high and while the cropland, pasture, and woodland areas still are relatively bare of foliage (fig. 43). Figure 44, the eastern. half of figure 48, shows a large part of Iowa west of Des Moines that is nearly all cultivated, mainly in grains. Gallery forests along streams are the chief natural vegetation. The image was taken on May 10, 1973, when the fields were either newly plowed or in young crops and when soil moisture remained relatively high; thus the darker tones registered in band 7 represent relatively moist soils, and the lighter tones, drier soils. Subtle variations in tone register the types of glacial and other surficial de- posits and landforms on which the soils have developed. Drainage patterns provide considerable information on the relative ages and types of glacial deposits and on the trends of both young and ancient end moraines. Com- bined with data from geologic, soil, and topographic maps, this image reveals useful information about surficial deposits and soils. Two principal units are obvious: (1) a relatively dark toned plain, the Wisconsinan till plain, in the northern half of the scene, and (2) a lighter toned, more dissected plain, the Kansan till plain, in the southern half of the scene. Clayey TVisconsinan till was deposited by a late-glacial ice lobe that reached as far as Des Moines about 14,000 yr ago, after the last period of active loess deposition had ended; consequently, its soils are moderately poorly drained and appear dark toned in this image. The narrow light—toned irregu— lar ribbons that traverse the \Visconsinan till plain in the image are well- drained sandy-gravelly glacial outwash and alluvium along stream valleys. An inner dark zone along some larger streams in the image represents poorly drained bottomland soils. The Kansan till plain has a mostly lighter tone in the image because wide- spread loess deposition has resulted in better-drained soils. Here the streams are more deeply incised and more numerous than in the TVisconsinan till plain, I nterpretation of geology and soils from ERTS images is especially difficult 67 68 ERTS—1, A New Window on Our Planet mass-ea: ID“ I NAG: lab) ' (3)081: 180 0 N302 IOU ‘ N502 unw- -—DOZ I 00 ! 03(00): IOOI-‘Dflz Ima c ms-Wwfi'fioém-W-w nss waggfiaévwfg nan-w-N—n-N-nifiynég i “is-Hg?!” APPROXIMATE SCALE 0 10 20 30 MILES 10 0 10 20 30 KILOMETERS FIGURE 43.——-Color composite ERTS—1 image of part of Iowa west of Des Moines (1291—16335). 2, Applications to Geology and Geophysics 69 and the main ones have cut deeply into bedrock. From stream alignments, two divisions of this area can be distinguished: a zone (2a1, 2a2) of arcuate drain- age immediately south of and parallel to the Bemis moraine and, farther south, a zone (2b) characterized by more deeply incised streams that radiate outward normal to the zone of arcuate drainage and the Bemis moraine. In the northern zone, the interstream divides commonly are tabular; they are widest in unit 2a2. About five principal divides can be identified. The parallel- ism of the streams to the Bemis moraine suggests that their alinement, before their entrenchment into bedrock, may have been controlled by a series of mid- dle Pleistocene end moraines and/or ice-marginal streams. The till beneath the present tabular divides may represent relics of these ancient moraines that were previously unrecognized. Supporting this hypothesis is the fact that the stream valleys cut across the boundaries of formations having considerable differences in rock type and resistance to erosion and are also transverse to a buried preglacial valley. In the southernmost zone (unit 2b), the streams run transverse to those to the north and show little or no control by former moraines. Because the drainage network is denser and the streams are more deeply incised than in the northern zone, probably a longer time has elapsed since this area was * glaciated. Figure 45 is another example of the usefulness of spring ERT S infrared imagery for mapping and analysis of glacial landforms, deposits, and soils in the Midwest. This region, in west—central Illinois, is almost entirely culti— vated, and the natural vegetation generally is confined to the steeper slopes and stream borders. The variations in tone are caused mainly by differences in permeability and moisture content of the soils, which in turn are related to the surficial deposits on which the soils have developed. On the mosaic, the VVisconsinan till plain is mainly dark toned (moist soils), and the Illinoian till plain is dominantly light toned (dry soils). On the VVisconsinan till plain, various end moraines are easy to distinguish from glaciolacustrine plains and ground moraine. On the Illinoian till plain, end moraines generally cannot be distinguished from ground moraines because here all the moraines are older and have been considerably modified by weath- ering, erosion, and loessial cover. An exception is the Bufi'alo Hart moraine (unit 2a), of late Illinoian age, that is intermediate in age and tone between the main Illinoian till plain (unit 2b) and the “Visconsinan units; this moraine also has light-toned mottles caused by hills of well-drained sand and gravel (kames) large enough to be detected on the image. Images also facilitate mapping soil associations for both agronomic and engineering applications. Comparison of ERTS-interpreted maps, such as figure 45, with soil association maps of Illinois shows that the boundaries be- tween certain soil associations stand out much more clearly on the ERTS images than on conventional aerial photographs and permit rapid yet highly accurate soil mapping over large regions. A striking example is the ribbon- like areas of well-drained soils the light tones of which contrast conspicuously with the prevailing dark tones of the “Visconsinan till plain. Although limited in areal extent, these soils are very important; they commonly overlie sandy- gravelly outwash deposits, locally of commercial quality, that are shallow aquifers and significant in places for domestic and municipal water supplies. They tend, however, to be droughty, of moderate to low agricultural pro- ductivity, and undesirable sites for sanitary landfills unless the fill is sealed off from the aquifer. 70 ERTS—1, A New Window on Our Planet APPROXIMATE SCALE 10 2‘0 30M|LES l J l l 10 20 iii [ilil 10 0—0—0 30KILOMETERS FIGURE 44.—Annotated ERTS—1 image 1291—16335, band 7 (fig. 43), with interpretation of soil types. FIGURE 45 (next page).—Mosaic of ERTS—1 images 1322—16051 and 1322—16054, band 7, west-central Illinois with interpretation b of soil types. I on: . muoz Iao-wmz lam ~ woz nose-3m IBJLN73 C maze/mama N ma-zywarsn ”SS mum c Mas-W33 n m-mgis 2, Applications to Geology and Geophysics uses-am “WEI MTEI 7 D SUN ELSI HZIIS ISl-‘I‘IBS-N-l’N-D’lL msa ERTS Evl322-iBGSI-7 8| 7 D S)! ELSZ fllem-QQkSS-N‘l-N-DflL man Mia-1W"! BI APPROXIMATE SCALE 10 20 30 MILES 10 20 30 KILOMETERS N 0 3 5 3 B I as - wuaz I am - muoz on: . «no: I 71 law - anoz loo-aha: 00 - \KDOE I ENHANCEMENT OF TOPOGRAPHIC FEATURES BY SNOW COVER By Roger B. Morrison, U.S. Geological Survey inter ERTS images of snow—covered areas are W the most favorable for showing topographic detail, particularly in regions of low to moder- ate relief. A continuous snow cover masks out the dis- tracting tone differences caused by variations in soils, rocks, and vegetative cover. Also, the low Sun-elevation angle, which is characteristic of winter images, results in shadowing and emphasis of even minor topographic features. Although the snow cover masks all spectral infor- mation about soils, rocks, and most types of vegetation, some deductions about soils and rock materials can be made from the landform and land—use characteristics. For example, one knows that sand dunes are composed of eolian sand and that valley bottom lands are under- lain by young alluvial soils. A good example of the enhancement of an image of a snow-covered region of low to moderate relief is shown in figure 46. This image of western Nebraska is representative of the semiarid central Great Plains. The maximum local relief is about 400 m. The bedrock units are nearly flat lying weakly consolidated silt, sand, clay, and some gravel and shale, capped in places by resistant limestone and carbonate-cemented sand- stone that produce plateaulike uplands. The bedrock is commonly covered by a veneer of unconsolidated eolian sand and alluvium, but it is well exposed in various es- carpments, bluffs, and dissected areas. This image was taken on Jan. 28, 1973, after widespread snowstorms and when the Sun-elevation angle was 24°. Note the fine details of gully patterns in the various escarpments and the dune morphology in the Sand Hills. Images of this area without snow cover show much less topo- graphic detail. Using this winter image alone, without information from images taken at other seasons and without any field data, three kinds of terrain can be identified: (1) dune fields (part of the Sand Hills of Nebraska), (2) valley bottom lands (flood plains and low terraces along several rivers), and (3) bedrock escarpments and surfaces of several types, some having thin veneers of surficial deposits (fig. 47). The dune fields can be di- vided into three subunits on the basis of dune morphol— ogy, degree of blowout development and (or) dune stabilization, and the abundance and pattern of crop- lands. The valley bottom lands are evident from their topographic position, land uses, and lack of relief. Four classes of bedrock surfaces can be distinguished from their topographic position, local relief, including depth and closeness of stream dissection, and field abundance and field patterns. Figure 48 illustrates the relatively poor topographic detail discernible in summer images. This band 5 image, taken Aug. 19, 1972, covers part of the same area shown in figure 46. In areas of high relief or of coniferous forest, snow cover provides less enhancement of topographic detail. Much detail is lost in the shadowed parts of moun- tains and canyons and on slopes that are more or less perpendicular to the Sun’s rays. The dark foliage of dense coniferous forests obscures the ground, snow- covered or not, the year around. Deciduous forests are less of an impediment because the leafless trees in win— ter do not entirely obscure the snow-covered ground. Description of geologic terrane-map symbols used in figure 47 (p. 74) 1a _________ High transverse sand dunes, closely spaced, with subparallel alinement; probably many active dunes; many interdune lakes and ponds. (Clearly inferred from dune forms.) 1b __________ Transverse and upsiloidal/longitudinal dunes with numerous blowouts; irregular alinement; probably many active dunes; interdune lakes and ponds more numerous than in la. (Clear- ly inferred from topographic form.) 1c __________ Poorly developed and/or eroded low dunes and cover sands; mostly stabilized; few interdune lakes and ponds; moderately thick to thin veneer of unconsolidated sand over bedrock. (Inferred from subdued dune morphology and variable field density.) 2 ___________ Valley bottomlands. Flood plains and low ter- races along main streams. (Inferred from topo- graphic position.) 33 __________ Low-lying erosion surfaces commonly between units 2 and 3b, sloping gently toward main 72 streams; low dissection and local relief; prob- ably widespread thin veneer of unconsolidated alluvium and local eolian sand and/or loess. (Deduced from topographic position, local re- lief, and field patterns.) 3b __________ Escarpments, bluffs, and hills without significant surficial deposits; highly dissected, common- ly grading into “badlands.” (Inferred from topographic detail.) 3c __________ Upland plains with few streams and shallow dis- section; low relief; probably extensively ve- neered by loamy soils. (Deduced from topo- graphic detail and generally dense field pat- tern.) 3d __________ Upland plains underlain by resistant caprock; few streams, shallow dissection, and low re- lief; probably patchy veneer of sand or loamy soil. (Inferred from topographic detail and less dense field patterns than in Se.) Iowa—m 2_ Applications to Geology and Geophysics 73 APPROXIMATE SCALE 0 10 20 30 MILES l i I J I ' ' l ' l | i | o 10 20 30 KILOMETERS FIGURE 46.—Color composite ERTS—1 image of western Nebraska showing snow-enhanced topographic details (1189—17075). ININO—Z lwi-‘m 74 ERTS—1, A New Window on Our Planet APPROXIMATE SCALE 10 0 10 20 30 MILES l 1 l l l l l l l l ' l I l I l 10 0 10 20 30 KILOMETERS FIGURE 47.—Geologic terrane map compiled on ERTS—1 image 1189—17075 (fig. 46). Explanation of symbols is on page 72. IDOIwLQZ ISOIhQ—E SQINLQZI IQQ'NDOZ “4183-30 NIB3-00l Hi83-30l Lil -80| ISRUG72 C N42-28/Nl82-47 N N42-28/Hl82-44 P158 5 D SUN ELSZ 92134 182-6378-G-I-N 2, Applications to Geology and Geophysics 75 H]BZ-3Bl NIGZ-BBI B3 Hl02 30 .D- - | 2L NHSR ERTS E-l027-l7070-5 Bl APPROXIMATE SCALE 10 20 30 MILES l 1 l l I l 10 20 30 KILOMETERS 10 [Ill] [llll 10 O——O FIGURE 48.—ERTS—1 image of western Nebraska in summer showing relative lack of topographic detail (1027—17070, band 5). IDQI—Q—E DQINAQZI IQOINASZ HYDROGEOLOGY OF CLOSED BASlNS AND DESERTS OF SOUTH AMERICA By George E. Stoertz and William D. Carter, US. Geological Survey 1972, of the central Andes, Atacama Desert, and Altiplano have been analyzed for hydrologic and geologic data. The study area includes southwest Bolivia, northwest Argentina, southeast Peru, and northern Chile, extending from lat 16°30’ S. to 27°30’ S. and from long 66°30’ 1V. to 70°30' W. Synoptic seasonal conditions revealed by ERTS for the first time, and delineated in this study, include midwinter and early spring snowpack on the main range of the Andes from lat 21°00’ S. to 25°20’ S. and seasonal floodwaters on the floors of closed drainage basins throughout the study area. Permanent features mapped at 1:1,000,000 from ERTS imagery include salars (salt—encrusted playas), drainage basins, volcanic cra- ters, calderas, conjectural faults, major structural trends, and the approximate extent of the ancient Lake Minchin. Experience has shown that color composite images provide 40 to 50 percent more environmental informa- tion than black and white images of the same scene. This was the conclusion of Dr. Carlos Brockmann and his associates of the Geological Survey of Bolivia (Geobol) after they made detailed studies of the stra- tigraphy, structural geology, hydrology and drainage basins, relative permeability, and geomorphology in the area. The ERTS—l false-color composite image shown in figure 49, taken on Aug. 2, 1972, is the first prepared for this region of the Andes, and it dramatically dis- plays the rugged terrain. Being largely composed of exposed bedrock and soil, the terrain pictured is domi- nantly pale green. The Salar de Coipasa is in the right; the distribution of water (black to pale blue) and salt ERTS images, obtained from July 30 to Oct. 30, 76 (white) is obvious. Part of the Salar de Uyuni is in the lower right corner. The Altiplano comprises the plains area to the north and is studded on the west by many volcanic cones. Some are lightly dusted with ephemeral snow, whereas others appear to have well— established snowcaps. Faint patches of vegetation ap- pear as small spots of pinkish orange, and most are natural vegetation near springs, but some patches may be farm plots and grazing areas frequented by in- digenous Indians and llamas. Linear features near the crest of the Western Cordillera (lower left) are part of the major copper belt—for which the Andes are famous—extending from Chile in the south into Peru to the north. Maps compiled largely from ERTS images and com- pleted in manuscript form (Stoertz and Carter, 1973) (figs. 50, 51, 52) show the following: 1. Of 150 salars, 86 were found to be in agreement with existing published and unpublished maps, 32 were modified by the ERT S data, 20 were revealed solely by ERTS, 7 were not identified on ERTS images but were retained from other sources and were unverified, and 5 were in small deflation basins (figs. 51, 52). 2. Of 184 closed drainage basins, 58 were classed as largely reliable and verified by ERTS, 69 Were largely reliable but unverified, 10 were fairly re— liable and modified by the ERTS data, and 47 were still unreliable or doubtful. 3. Of an experimental evaluation of part of a pub- lished geologic map (1:1,000,000) covering 9,300 kmz, 40 percent appeared to be essentially in agreement with boundaries visible on ERTS images, 35 percent appeared subject to improve- ment by boundary adjustments, and 25 percent was estimated to be subject to significant revision with the aid of ERTS imagery. 4. Of 681 volcanoes or craters, including 9 active vol— canoes, the position of 1 was corrected from ERTS data. Of 15 calderas, 5 were mapped solely from ERTS images. 6. 2,160 km of previously mapped faults were recog— nized on ERTS images, plus 225 km were map— ped solely from ERTS data, the latter consisting of conjectural extensions of known faults and realinements of mapped faults. 7. Major structural trends associated with the promi- nent bend in the Andean fold system, chiefly in Bolivia and Argentina, were identified. 8. Of 9,840 km2 of early spring (October 30) snow- pack on the main range of the Andes, 6,215 km2 was in interior drainage basins of Chile, 1,295 in Bolivia, 1,035 in Argentina, and 1,295 in the external drainage basin of the Rio Loa. 9. Of 88 lakes or seasonal floodwaters in midwinter and early spring (August—October) , 29 were simi- lar to lakes on existing maps, 23 were modified by ERTS, and 36 were mapped solely from ERTS. A special study of the relation between seasonal floodwaters in the high Andes and drainage—basin char- acteristics revealed that, where more than 0.3 percent of a drainage basin was covered by water during August—October, the basin generally was found to meet the following criteria: (1) mean elevation of 4,050 m or higher, (2) mean elevation of drainage divides, 4.350 m or higher, and (3) snowpack covering more than 10 percent of the basin on October 30. Of 36 drainage basins for which October snow-cover data were available from ERTS data, 16 basins met all three criteria. These 16 basins included every one of the 13 extensive lakes or floodwaters seen on ERTS images at that season and in the special study area, extensive being defined as exceeding 0.3 percent of basin area. These conclusions will assist in future water—resources appraisal and prediction. No single source of data previously has permitted identification of all these features, and observation of synoptic snow cover and surface water was not possi- ble before ERTS. The satellite thus provides an in- valuable source and type of data for Earth resources surveys and development in this large and relatively undeveloped area. SJ( 2, Applications to Geology and Geophysics 77 EXPLANATION FOR FIGURE 50 International boundary Settlement of Sabaya, approximate (not visible on ER TS image) Inactive volcanoes verified approximately correct as previously mapped (only principal volcanoes are shown) Inactive volcano moved eastward about 3.2 kilometers from position previously mapped Active volcanoes, the northern one shown 3. 2 kilometers east of position prevw' usly mapped Portion of caldera verified correct as previously mapped (near left edge) Portion of caldera modified from ERTS imagery (near left ..,. edge) (.7 Caldera mapped solely from ER TS imagery (near left edge) Principal faults visible on ERTS image, shown approximately as previously mapped (6 faults trending NW and NE) ----------- Faults inferred or modified from ERTS imagery (3 faults trending northwest) Major lineaments in the Andean fold belt (limited to northeast corner) ~~_..” Zme of lead-zinc and copper mineralization (from published sources) Zone of silver mineralization (from published sources) Surface flooding in Lago de Coipasa, August 2, 1972 (elevation approximately 3680 meters) Deep water Shallow water Very shallow water and surface moisture Lakes approximately as previously mapped (l are shown) lakes or seasonal floodwaters significantly different from, or not delineated on, available maps (17 are shown) Salar margins verified approximately correct as previously mapped Salar margins modified from ERTS imagery Rivers verified approximately correct as previously mapped River modified from ERTS imagery (southwest corner) Strand line of ancient Lake Minchin, approximately as delineated on previous maps ’J-uk.‘_‘. \— Probable strand line of lake Minchin, as inferred from ER TS imagery Notes: Coordinates shown in margin are as shown on ERTS image but are not in agreement with coordinates on published maps Image ID No.: NASA ERTS E-1010-14035—4/5/7 low I (0010!: 00' 0—00). 00¢.)- 0—D“) 78 ERTS—‘l, A New Window on Our Planet IRS-Ml m-Nl m-wl fi- - m-Ml -%l m5 lgm-TI N SiS-Ol’fifiliss 5, R SUI EL36 92048 189-8l 7-R-l-N-D-2L WISH ERTS E-lOlO-l OI APPROXIMATE SCALE 10 O 10 20 30 M IL ES 10 0 10 20 30 KILOMETERS FIGURE 49.—Color composite ERTS—1 image of the Salar de Coipasa region of Bolivia and Chile (1010-44035). [SO I m—mm law 7 (9—00) 2, Applications to Geology and Geophysics 79 Q 69‘” 9 , 68W "4*" Volcon Po'aiv’inacota Salar de Uyuni l APPROXIMATE SCALE 10 0 1'0 210 3'0 MILES l l 10 0 10 20 30 KILOMETERS FIGURE 50.—Geologic and hydrologic interpretation and explanation of features identified in the Salar de Coipasa region as de— rived from ERTS—1 image 1010—14035, band 5 (fig. 49). Explanation is on page 77. 80 ERTS—1, A New Window on Our Planet FIGURE 51.—|ndex map of salar revisions with area of figure 52 outlined. From sheet 14 of l'The World,” 15,000,000, pub— lished by the Defense Mapping Topographic Command, 1973, series 1106, edition 4; original map compiled and drawn by the American Geographical Society. 70° y 68° 66° FIGURE 52.—Example of outlines of several salars revised by ERTS data. W EST 24° 24 SOUTH 100 MILES l 100 IOOKILOMETERS Original map compiled and drawn by the American Geographical Society of New York, Broadway at 156 St, N. Y. Copyright by the American Geographical Society of New York. Prepared and published by the Defense Mapping Agency Topographic Center, Washington, D. C. 26° 67° * , 1 ERTS ‘BQTH US. Air Force Operational Navigational Charts 10 0 10 20 30 MILES 10 0 10 20 30KILOMETER$ seas and illustrates the use and value of ERTS imagery for this purpose (McKee and Breed, 197 4). The study consists of the identification, descrip- tion, and measurement of characteristic forms and structures within the world’s principal sand bodies. This work will facilitate the determination of world distribution of the various dune types and their classi- fication. In addition, the basic forms of sand deposits, analyzed together with data derived from field observa- tions, make it possible to determine the processes re- sponsible for each dune type. ' The advantages of employing ERTS images in this study are readily apparent. Because all images have the same scale, direct comparisons of widely separated areas are possible. Further, the relations of the sand areas to their surrounding features are easy to recog- nize, and major lineations or other patterns in the sand areas are clearly defined. Finally, mosaics made from combinations of images make excellent map bases on which to superimpose many kinds of data. For purposes of this study, 15 desert or semidesert areas, all of them in the Eastern Hemisphere, were initially selected (fig. 53). Subsequently some of these study areas were combined and others were reduced in size in order to eliminate nonsandy areas and to con- solidate mosaics for greater efficiency in handling data. A few relatively small areas located in the Western Hemisphere (fig. 53, inset) were later included in the study primarily because they were easily accessible. These small areas were chosen because they can be checked readily by aerial photography, and, for most of them, field notes are available for interpreting the origin of the morphology. The methods used in this investigation have gradual- This investigation is a global study of desert sand SAND SEAS OF THE WORLD By Edwin D. McKee and Carol S. Breed, U.S. Geological Survey ly evolved from experience in employing the various types of ERTS imagery as they have become available. Initially, only small black and white negativeswere received, and they were scarcely adequate for careful analysis. \Vith the availability of relatively large prints and their enhancement by photoprocessing methods, both through printing techniques and differences in paper, considerable improvement was made. Being able to compare prints from the green, red, and near-infra- red bands was another major advance, for it facilitated the recognition of water, vegetation, and other associ- ated features bordering sand bodies. Finally, when false—color images became available (fig. 54), the dis- cernment of sand through its characteristic yellow color placed the study of sand bodies through the inter- pretation of ERTS images on a high level of accuracy. A principal. aim of this study is to develop an ob— jective classification system of the major types of eoli- an sand deposits (McKee and others, 1973). Although a final proposal is as yet far from ready, a preliminary classification, based on dune forms seen on the ERTS imagery thus far examined, recognizes the following five basic types: (1) parallel straight or linear, (2) parallel wavy 0r crescentic, (3) star or radial, (4) parabolic or U-shaped, and (5) sheets or stringers. Parallel-straight or linear dune complexes are de- fined as sand bodies in which the length is much great- er than the width, slip faces or steep avalanche sur- faces occur on both sides, and the ratio of dune area to interdune area is roughly 1:1. Examples of such linear complexes are conspicuous on ERTS images of the Simpson Desert of Australia, the Kalahari Desert of South Africa (fig. 55), the Empty Quarter of Saudi Arabia, and the Sahara of North Africa. Variants of the linear form are the feather type in Saudi Arabia 81 82 ERTS—1, A New Window on Our Planet and the wide—intradune type in the Sahara. Parallel-wavy or crescentic dune complexes consist of nearly parallel rows of cuspate segments, as repre- sented in the Kara Kum Desert of the U.S.S.R. and in the Nebraska Sand Hills of the Western United States. Variants of the simple basic type are referred to as the fish-scale type of the Great Eastern Erg of Algeria, the giant—crescent or megabarchan type of Saudi Arabia (fig. 56), the bulbous, warty type of the Gobi Desert in China, and the chevron or basket—weave type of the Takla Makan Desert in China. Star or radial megadunes commonly attain great height and include a few to many arms that project out from a central cone in various directions. The basic type, resembling a giant pinwheel, is scattered at ran- dom in parts of the Great Eastern Erg of Algeria. In other parts of Algeria (fig. 57) and in the Gran Desier- 30°W 0° 30°E 60° 90° 120° 150° to de Sonora in Mexico (fig. 54), chains of star dunes are characteristic, whereas in the Empty Quarter of Saudi Arabia there are star dunes of graduated sizes, from small to very large. Parabolic dunes that typically develop U- shapes with arms drawn out on the sides are common in areas where vegetation or moisture, or both, tend to anchor the arms while the center is blown out and its sand moves forward. Good examples of these dunes are in the Rajasthan Desert of India (fig. 58) and at White Sands, N. Mex. In some sand seas, definite geomorphic forms fail to develop, and the sand accumulates in flat sheets, as near Lima, Peru. Elsewhere it may form stringers ex- tending downwind without appreciable relief, for ex- ample, as in South—VVest Africa (fig. 59). a7}. ‘7... TROPIC OF CAPRICORN EXPLANATION A Location of figures 55 thru 59 ' Arid and extremely arid desert regions (after Meigs, 1951) m ERTS-l test sites within the seas of Africa, Asia, ° Australia, and North America ,120°w 90‘°W NORTH AMERICA .. ME 0 _ ‘fRTo Pic "Ci—rtTEAN—C’ET?‘ ‘ ASIA \ a _______________ T310319 9f .9“ ”FEB _ _ _ FIGURE 53.—lndex map of the sand seas of Africa, Asia, Australia, and North America. 2_ Applications'to Geology and Geophysics 83 KEYS TO SAND-MOVlNG WINDS Wind rose arms point upwind Length proportional to occurrence of given speed GENERALIZED WIND ROSE Group from given direction as percentage of all observations 5.5 mm arm length equals 10% occurrence High energy winds M . K1 1:] Winds 17—21 kn - Winds >21 kn °derate energy W'"d$ Percentage calm K2 I:l Winds 11—21 kn - Winds >21 kn ‘ JUL{Period of observations /Time of observations K3 [:I Winds 4—21 kn - Winds >21 kn MORNING (ifavailable) K1/Key number Percent occurrence by K4 direction only-no speed data FIGURE 54.—Color composite ERTS—1 image mosaic of the southwest United States desert and the Gran Desierto de Sonora in Mexico. ERTS—‘l images 1178—17495, 1160—17503, 1178—17504, 1159—17445, 1159—17451, 1176—17385, 1176—17391, and 1230—17400. 84 ERTS—1, A New Window on Our Planet iSGZS-S’B $561849! wishes: EGIS‘QQI "é a 2 £1 a a ! N13 ‘ UVNEJU‘J ”ms I HINGE!!! Ema-am ,9. 7 EB 81‘32! E B! 27HHY73 C 524*2 61841411 SZ‘i-ZBfiZBiB-“S i185 ‘3 R SUN EL3I R284! iBB-‘QBS-WF L NHSF! ERTS E-lSBB-BSIB‘IW‘ Bl APPROXIMATE SCALE 0 10 20 30 MILES 10 O 10 20 30 KILOMETERS FIGURE 55.—Coior composite ERTS—1 image showing parallel-straight or linear dunes in the Kalahari Desert of South Africa (1308— 08104). ”- r , ’ ";/‘r/AJ 11/" ‘f/> ; . 4/ ' v. ,J/T'fvf/fiir ’ 1'» Kr“ I/{r ,VV/rflfr rw/Vrru ‘ r” ’ (’1‘ 7‘ fr; , v 3h V { ‘ ‘1, , 4' momm-aumm APPROXIMATE SCALE 0 I l I I | I 0 10 20 2, Applications to Geology and Geophysics 85 mfg" r A "W m {A ' 57‘ij " 1%,, ' J44“; 5‘ ‘ r ‘I r ‘ 59.??? {/fiffryh 1; 4 0.0 ’4 ”r 30 MILES A i I 10 20 30 KILOMETERS FIGURE 56.—Color composite ERTS—1 image showing parallel-wavy or crescentic dunes (a megabarchan desert) in Saudi Arabia (1183— 06194). now-m IOUI-m In!“ I00 I (ONOZ lot-3 I @1002 i can comm 86 ERTS—1, A New Window on Our Planet iE604-80 N628-3Bl iEOG‘i-SB zoos-am FIGURE 57.—Coior composite ERTS—1 APPROXIMATE SCALE 0 10 2'0 3'0 MILES I I l ' ' I ' I l l | o 10 20 30 KILOMETERS image showing star or radial megadunes in Algeria (1111—09442). E805 - 30 I DO I (ONO: I law I @1002 l 90 I QNOZ [Ow I 0100!“ 2, Applications to Geology and Ceophysicg 87 lEBSS-BG EBSS-Bal EB7B-08l I80|MNQZ IDQIDNSZ E 8 7 8 3 0 Iownmmom DDIDNOZI EGGS-001 E869-3GI EB7B-BQI l2JFlN73 C N2‘l-27/EBSS-3‘I N N24-28/E889-38 H88 5 R SUN EL34 H2l43 l88-2485-Fl-l-N-D-2L NRSH ERTS E-l 173-852ll Bl APPROXIMATE SCALE 10 20 30 M | LES u-lTFfil—r—‘fi—fl‘L—‘J 10 0 10 20 30 KILOMETERS FIGURE 58.——Color composite ERTS—1 image showing parabolic dunes in the Rajasthan Desert of India (1173—05211). 88 ERTS—1, A New Window on Our Planet EOIS'SGI APPROXIMATE SCALE 0 10 20 30 MIL ES 10 0 10 20 30 KILOMETERS FIGURE 59.—Color composite ERTS~1 image showing flat sheets and stringer dunes in South-West Africa (1109-08054). DETECTION OF HYDROTHERMAL SULFIDE DEPOSITS, SAINDAK AREA, WESTERN PAKISTAN By Robert G. Schmidt, U.S. Geological Survey Nov. 25, 1972, (fig. 60) shows the known porphyry copper deposit at Saindak, in western Pakistan, and several sites chosen for further pros- pecting on the basis of information from this image and known geologic data (Ahmed and others, 1972; Schmidt, 1973). Porphyry copper deposits are large bodies of weakly mineralized rock generally containing minerals associated with hydrothermal alteration. Zones containing different alteration minerals tend to be concentric outward from a core and commonly include large volumes of pyrite-bearing rock. Under opti- mum conditions, the topographic forms and surface-coloration anomalies of light-toned anomalies related to the weathering of these deposits are so large and distinctive that they can be recognized on ERTS—l images. At Saindak a group of small copper—bearing porphyritic quartz diorite stocks surrounded by zones of hydrothermal-alteration minerals cut north— ward across the entire folded lower Tertiary stratigraphic section. The stocks have undergone intense sericitic alteration and contain copper sulfides. The stocks are enclosed in a pyrite-rich envelope that is in turn surrounded by a hard dark—appearing zone of propylitic alteration. The sulfide—rich zone, in- cluding the porphyry stocks, has been eroded out to form a valley that appears light toned on the image (fig. 61, A). The zone of propylitic alteration forms a symmetrical rim of hills more rugged than the surrounding region and appears darker in tone (B). Together these features are several kilometers across and form a visible target on the image that is much larger than the actual exposed area of mineralized rock. Both the central valley and dark rim are displaced left laterally by a major east-trending fault (C). The region around the Saindak deposit is a geologically favorable area for deposits of the porphyry copper type, and it was studied for evidence of other deposits by using composite images and photogeologic maps and field mineral-reconnaissance data. Three sites on this image, not formerly regarded as potential prospects for large sulfide deposits, were identified (D, E, and F), and one former prospect (G) was reevaluated. These four sites are recom- mended for field examination. All are areas of known intrusive stocks. At site D, a small rugged area near the intrusive may be due to propylitic alteration. Dark—appearing hilly areas surround central cores having a light tone and low topographic form at sites E, F, and G, and skarn—type hematite or magnetite bodies have been reported from the vicinity of E, F, and G. Unfortunately, be- cause windblown sand is abundant in the central cores of these three sites, the image does not show absolutely that the bedrock there has a light tone, al- though the combinations of colors and bands were chosen in this and other composites to enhance the difference. T he digitally enhanced false—color composite of an ERTS—l image dated 89 90 ERTS—1, A New Window on Our Planet Evaluation of the techniques used here will be possible after field checks have been made of the sites suggested, but positive identification of any por- phyry-type deposit must be followed by extensive evaluation before it can be known Whether the deposit is exploitable. APPROXIMATE SCALE 10 20 30 MILES O 10 20 30 KlLOMETERS FIGURE 60.—Digitally enhanced false-color composite ERTS—1 image of the Saindak area of western Pakistan, prepared by IBM Corp., Gaithersburg, Md., using band 4 (blue light), band 5 (green light), and band 7 (red light) (1125—05545). 2, Applications to Geology and Geophysics 91 lE081-38 EBGZ-Ofil N029-38l IE062-30 E883-00l saw I LDNQZ I I09 I (.9st I80 I LONGZ I SOL) ' mwoz E B 6 I B 8 OS I (.0QO I l 80 I mNDZ I88 I (DNSZ lN828-00 E081 '30I EBSZ-BBI E662-30l 25NOV72 C N28-42/E062-Bl N N28-4l/E682-03 H88 7 R SUN EL34 92150 180-1738-H-l-N-D-1L N888 ERTS E-1125-05545-7 Bl APPROXIMATE SCALE 10 0 10 20 30 MILES W 10 0 10 20 30 KILOMETERS FIGURE 61 .—Annotated ERTS—1 image showing location of significant geologic features of the Saindak area of Pakistan (1125— 05545, band 7). STRUCTURAL GEOLOGY AND MINERAL-RESOURCES INVENTORY OF THE ANDES MOUNTAINS, SOUTH AMERICA By William D. Carter, US. Geological Survey he evaluation of the use of ERTS—1 images as a tool for improving knowl— T edge of the structural geology and mineral resources of the Andes is a cooperative project with geologists of South American resource agen- cies. The program is based on the idea that exchange of interpretive results between scientists will raise the level of confidence in interpretation and im- prove the use of these new data acquired by remote sensing. The objective is to establish models and procedures that Will ultimately lead to mapping of the entire Andean chain—and eventually the South American continent—0n a common base and with standard procedures. Hopefully this work will provide new information for the “Tectonic and Metallogenic Maps of South America” and will define new areas for mineral exploration. Of 12 areas proposed for study under this experiment, the first area for which an ERTS image collection was most complete was that of the La Paz region. A mosaic of 22 images covering an area of 275,000 km2 between lat 16° and 20° S. and long 66° and 72° W. was compiled at a scale of 121,000,000 by the US. Geological Survey (fig. 62). Band 6 images of reflectance in the near- infrared region (0.7—0.8 p.111) were selected for the mosaic. Copies were then sent to cooperating investigators in Bolivia, Chile, and Peru for evaluation and interpretation. Four map overlays of the La Paz orthoimage mosaic have thus far been prepared that provide a preliminary understanding of the region. The first was an image linear map (fig. 63) in which all natural linear features, gener- ally greater than 10 km in length, have been identified. Those lineations, be- lieved to be mostly fractures and faults, are indicated by long dashed lines; lineations related to bedding planes of strata are indicated by short dashed lines. Volcanic cones, craters, and calderas are also depicted to place them in the regional tectonic framework. The completed interpretation was then compared to existing published maps and to the interpretive products made by other cooperating investigators. This comparison resulted in a “relative confidence map” (fig. 64) on which linear features noted on published maps 92 2, Applications to Geology and Geophysics 93 were indicated in red and those noted on ERTS imagery by two or more inter- preters in green. Coincidence of the preliminary plotting of linear features from ERTS imagery to the other sources was high. A metallogenic map was made by combining published information from Peru, Bolivia, and Chile at a common scale of 1:1,000,000. From this and the image linear map, a revised metallogenic map for the area was drafted (fig. 65). This product is now being evaluated by the cooperating investigators. A fourth map of related interest is a seismic-hazard map (fig. 66) that shows the location of epicenters of earthquakes occurring between 1963 and 1973 and having a Richter magnitude of 5 or greater. These data were ac- quired from the World Wide Seismic Net, and the epicenters are believed to be accurate within 25 to 50 km. Although the relationships between linear fea- tures shown on the image linear map and the areas of high seismic hazard are not necessarily direct, one may infer that some of the surficial structures indi« cated on the image linear map are connected to deep-seated seismically active structures. The relationship of volcanic activity to the movement of ore-form- ing fluids remains an interesting geological problem. Whereas much remains to be done in this program, the following conclu- sions can be stated: 1. ERTS—l images, because of their synoptic view of large areas, consistent Sun angle, and internal geometry, are ideal for mapping geologic struc- tures in large remote areas of the world. 2. The flexibility provided by several multispectral bands produces useable data for both arid plains and humid jungles as well as intermediate regions. Bands 6 and 7, providing near-infrared reflectance information, are considered the best for most geologic information because water bodies and soil moisture are depicted so clearly and the effects of vegeta- tive cover are reduced. 3. Color composite images, although the number available of South America still is very low, have been found to increase geologic interpretability by 40 percent (Brockmann, 1974). This fact provides strong support for constructing future mosaics in color. 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I / I I = I ,’ O 50 KILOMETERS l I \ 20s I I \ I | I .‘ [Salar De Uyum‘ | FIGURE 66.—Seismic-hazard map of the La Paz area. CLUES TO GEOLOGIC STRUCTURE POSSIBLY INDICATING OIL AND GAS SOURCES By Ernest H. Lathram, U.S. Geological Survey launch of the satellite shows a part of the foothills and coastal plains near Umiat, Alaska. Umiat was the major staging area for the Navy Department’s exploration of Petroleum Reserve No. 4 in 1945—52 and is the site of a medium-sized oilfield discovered during that work. The image repre— sents the near-infrared light reflected from Earth at the time of the overflight, and, because water absorbs infrared light, lakes and streams appear black in sharp contrast to land areas. The clear view of the distribution of lakes in the coastal plain over this large area provided information on the geologic struc- ture not heretofore recognized (Fischer and Lathram, 1973). Lakes in the coastal plain are known to be predominantly elongate, their long axes parallel and trending about N. 9° W. In figure 68, an additional strong east—trending regional lineation, not previously recognized on aerial photographs or in field study, is seen in linear interlake areas, alinement of some lakes, and elongation of some others. The trend of this lineation is parallel to the trend of deflections in contours of the magnetic and gravity fields in the area and is parallel to westerly deflections in the northwest ends of northwest-trending folds mapped to the south. In addition, the alinement of many small lakes forms a large and small ellipse superimposed on the regional lineation. Sparse seismic profiles show both periodic reversals in dip and a regional arching in shallow strata beneath the lineated area. These data suggest that concealed structures may exist in this area that may have concen- trations of gas in shallow strata and of oil in deeper strata at or near basement. Study of additional ERTS images shows that the observed lineation is prominent in the coastal plain from the Ikpikpuk River east to the Canning River and that this lineation may be useful as a guide to petroleum exploration throughout this area. The lineated area includes the sites of Prudhoe Bay and other recently discovered oilfields. An ERTS image of northern Alaska (fig. 67) taken only 4 days after the 99 a) '54 A” ‘5‘) I NM) . LUIU’ '1 MN ‘ N JN.’ IIVN ‘ } JIH INN' 100 ERTS—1, A New Window on Our Planet A354~88l 274615925 76 essay/u i was N”lv%‘§3§%§d s” E? 53 5? an FIGURE 67.—-Color composite ERTS—1 image of the foothills and coastal plains near Umiat, Alaska (1004-21395). II III 10 Hl53'08l APPROXIMATE SCALE 0 10 l l l I l 10 20 n sufilgiégafizievkz 20 l I 30 KILOMETERS msz-ao: 3'0 MILES ®®|“U1~VEZI z I now I (00765) INN ‘ “NW—4 NIX) ' 1003(983 l 2, Applications to Geology and Geophysics 101 ' LINEAR FEAruggs * Contocl W Fold axes ......, ‘1 .—~. Elongation of lakes M “—— Mogoefic, agomalfi? .. .;- Deflection in ‘éraéity coiltours ”wfiwtinwfion in lakes ' APPROXIMATE SCALE 10 0 lo 20 30 MILES l l l | l I J l ' ' l ' l l l l 10 0 10 20 3° KILOMETERS FIGURE 68.——ERTS—1 image of the Umiat area of Alaska showing structural features and lineation of lakes (1004—21395, band 7). DISCRIMINATION OF ROCK TYPES AND DETECTION OF HYDROTHERMALLY ALTERED AREAS IN SOUTH-CENTRAL NEVADA By Lawrence C. Rowan and Pamela H. Wetlaufer, US. Geological Survey, and A. F. H. Goetz, Jet Propulsion Laboratory combination of digital computer processing and A color compositing of ERTS MSS images has been used to detect and map hydrothermally altered areas and to discriminate most major rock types in south—central Nevada (Rowan and others, 1974). The technique is based on enhancement of subtle visible and near—infrared reflectivity differences asso— ciated with variations in bulk composition. MSS spec- tral bands are ratioed, pixel by pixel, by a computer and are subsequently contrast stretched to enhance the spectral differences. These stretched-ratio values are used to produce a new black and white image that shows the subtle spectral reflectivity differences and concurrently minimizes radiance variations due to albedo and topography. Additional enhancement is achieved by preparing color composites of two or more stretched-ratio images. Color variations seen in these stretched-ratio color composites represent spectral re- flectance differences (fig. 69). The choice of MSS bands for ratioing depends on the spectral reflectance properties of the surface ma- terials to be discriminated. For south-central Nevada, the most effective stretched-ratio color composite for discriminating between altered and unaltered areas and between the regional rock units was prepared using the following color and stretched—ratio image combination: blue for MSS 4/ 5; yellow for MSS 5/6; and magenta for MSS 6/7. In this composite (fig. 69), mafic rocks, mainly basalt and andesite (A), are white, whereas fel- sic extrusive and intrusive rocks are pink (B). The felsic rocks are especially notable because they have a large intrinsic albedo range, which commonly prevents their discrimination from mafic rocks in other types of images and photographs. Vegetation in the composite is orange, the darker hues representing denser vegetation. Although rock type is generally masked by the denser vegetation, some discrimination is possible among the flows and 102 tuffs on Pahute Mesa (C) where the vegetation cover is less dense (light orange). Playas and the two mining dumps on the western border of the Goldfield mining district (D) are blue. Clouds (pink-brown) and cloud shadows (white) can be identified with the aid of the standard color composite image in figure 70. Altered areas on figure 69 are represented by green (ID) to dark-green (E) and brown (F) to red-brown (G) patterns in the color-ratio composite. Except for two areas (H and I), the green areas represent hydro- thermally altered, commonly limonitic rock. The dark- green, brown, and red-brown patterns are less prev- alent. Dark-green areas are limonitic and limonite- free altered rocks. Areas that are brown in the color- ratio composite have been studied in less detail, but they appear to be predominantly light-colored hydro- thermally altered volcanic rocks. The red-brown pat- tern represents limonite-free, silica-rich, light-colored volcanic rocks that have conspicuous alteration in two areas and questionable alteration in two other areas. Altered outcrops mapped from the stretched—ratio color composite show a pronounced coincidence with known mining areas. In the Goldfield mining district (fig. 69, D), the most productive district in the study area, the degree of agreement between the green pat- terns and the previously mapped alteration zone is very striking. These altered areas are not apparent on the individual MSS images, color-infrared composite (fig. 71), or on color photographs obtained from Sky- lab. Therefore, the technique used in this study appears to have important applications in mineral-resources exploration and regional geologic mapping. Future re- search should focus on refinement of this technique, especially on defining more clearly the relationships between visible and near-infrared spectral reflectivity and mineralogical composition and on testing the tech- nique in a variety of geologic settings and environ- mental conditions. APPROXIMATE SCALE 5 5 10 1 5 M1 LES L—I—1Lr*n'w-I——r--L-r—-1J——-—l 5 O 5 10 15 WLOMETERS -central Nevada made from com uter com- FlGURE 69.—Stretched-ratio color composite ERTS—1 image of south patible tapes (part of 1072—18001). TRETD! * cum STRETCfl (H98 10m~1m~e~3 K-I W’L’ N3?~28 “117-435 REE .8'1. 3 ~ 3m: $34743 063322 .PL/IPL 5 O 5 10 15M|LES Ll_1||I I I III!!! 5 O l I I 5 10 15 KILOMETERS FIGURE 70.—Color composite ERTS—1 image of the south-central Nevada area made from computer compatible tapes (part of 1072—18001). noon-duo: OW'D-W‘ll II" 19-“ Ill 17-3! II III 10 FIGURE 71.—Conventiona| color cq 2, Applications to Geology and Geophysics 105 Ill IT-QI HI W-al APPROXIMATE SCALE 10 20 30 MILES I I I I l J 10 20 30 KILOMETERS O—I—O mposite ERTS—1 image of the entire south-central Nevada area (1072—18001). ”0 I000“: IQOIW NEW METHOD FOR MONITORING GLOBAL VOLCANIC ACTIVITY By Peter L. Ward and Jerry P. Eaton, US. Geological Survey he ERTS data collection system (DCS) makes it feasible for the first time to monitor the level of activity at widely separated volcanoes and to relay these data rapidly to one central office for analysis (Ward and others, 1974). This capability opens a new era in volcanology, and the hun— dreds of normally quiescent but potentially dangerous volcanoes near popu- lated regions around the world can now be economically and reliably (moni- tored daily to warn when any one volcano is becoming active again. Before ERTS was launched, only a few volcanoes in the world were monitored con- tinuously because of the high cost of building and staffing volcano observa- tories. Yet it is known from data collected in this century that while visible signs of pending eruptions may occur only minutes to days in advance, in- visible but measurable signs may be detected days, weeks, months, and even years before a major eruption. Although the prediction of specific eruptions is still an evasive goal, early warning of a reawakening of a quiescent vol- cano is now a distinct possibility. A prototype global volcano-surveillance system was established as part of the ERTS program. In cooperation with local scientists, instruments have been installed 011 15 volcanoes in Alaska, Hawaii, Washington, California, Iceland, Guatemala, El Salvador, and Nicaragua at the sites shown in figure 72 (Ward and others, 197 4). Data from these low-powered instruments in each of these many remote locations are being relayed 6 to 10 times daily through the satel- lite to the ground tracking stations at Goldstone, Calif, and Goddard Space Flight Center, Greenbelt, Md. The data are processed at Goddard and then relayed within 90 min by teletype to the National Center for Earthquake Re- search in Menlo Park, Calif. The sensors include 19 seismic-event counters, which count four different sizes of earthquakes, and six biaxial borehole tiltmeters, which measure ground tilt with a resolution of 1 ,urad. Only seismic and tilt data are collected be— cause these have been shown in the past to indicate most reliably the level of volcano activity at many different volcanoes. Furthermore these parameters can be measured relatively easily with new instrumentation. A fourth—genera— tion seismic-event counter was especially developed for this project. This in- strument compresses seismic data gathered at the rate of about 2 million digi- tal bits per 12 h to the 64 bits that can be economically relayed through a satellite. This compression is not easy, and some data are lost. For the pur- 106 2, Applications to Geology and Geophysics 107 ORAINIER 0 ST. HELENS NATIONAL CENTER LASSEN " GODDARD FOR , C—SPACE FL /GH7’ 90.: EARTHQUAKE RESEARCH ‘c‘ CENTER O KILAUEA D 1‘ 1" IZALCO SANT|AGUITO / TEL'CA/e FUEGO / CERRO NEGRO PACAYA 1,50. 1310. “DOSAN CRISTOBALgoo ,0. l | l FIGURE 72.—Map showing instrument sites of the prototype volcano-surveillance system. poses of this project, however, the main data desired are simply the number of events of different sizes. These numbers typically change by orders of mag- nitude before eruptions. The criteria adopted for detecting events are (1) that 10 peaks of the full-wave rectified seismic signal must be above a given threshold in 1.2 s and (2) that there must have been no peak above this thres- hold in the previous 15 s. The second criterion effectively inhibits the counter during periods of high ground noise caused by wind, harmonic tremor, people, and so on. The time that a channel is inhibited is counted separately and in- dicates the relative level of ground noise. The number of earthquakes greater than four different amplitudes and the noise counts for each channel are re— layed through the satellite. A typical installation is shown in figure 73. A tiltmeter is also used in this project. The bottom of the pipe, which is about 5 cm in diameter, contains a precise electrically monitored bubble level that has been adapted for this use from a defense application. The pipe is placed in a 1.3- to 3-m hole in rock or, more typically, sandy soil or ash. The output of the electronic equipment shown connects directly to the satellite transmitter. Data received through the satellite show that the instruments work as anticipated. Three tiltmeters in Hawaii recorded a 10- to 30—prad subsidence of the summit Kilauea Volcano during an eruption of May 5, 1973. Volcan Fuego in Guatemala inflated by about 25 “rad during the 6 mo following an erup- tion in February 1973. Events of two different sizes counted on Volcan Fuego, which erupted be- ginning on Feb. 22, 1973, show an increase in activity during the eruption (fig. 7 4). The counter was installed in early February. There was a significant in— crease in activity about 5 days before this small eruption began. The seismic 108 ERTS—1, A New Window on Our Planet activity was high during the eruption and returned to a low level after the eruption was over. A different counter 30 km from Fuego showed no change in seismic activity during the whole period. This fact implies that the seismic activity was indeed at Fuego. The prototype global volcano-surveillance system developed as part of the ERTS program clearly demonstrates the technological and economic feasibil- ity of building a global surveillance system, but many details in the design of highly reliable instruments still need to be worked out. The primary effort in the future will be the collection and analysis of data from these different volcanoes to establish clearly the scientific feasibility of this novel and p0- tentially revolutionary approach to surveillance of hazardous volcanoes. VOLCAN F UEGO, GUATEMALA u] _ 2 l O 20— I' Z Z 0 I n I In.h IL I "I ' ‘ I ' I 2 (D 200 [L g .00 i .,. . l '2 40— Lu > U] 20.. o I l I I IIThII-rniilrIIlerrrL‘n .ILmI M. H'IHPwm-«l. l ASH ERUPTIVE ACTIVITY STEAM\ ASH+UWA As"? may ASH? 9m | I II II II ZOHIGH— —? 02 2m LOW—I to: 5gp- l l I I l I I I I I 17 NOISE a 8 if? 3 3 I 5‘ -3’ 3 : a :a 3 a —: 3 HIGH GAIN § § .LLLLLJJ EVENTS 0 § § Mil-rm ........., . . ... ............,.”v"l FEBRUARY MARCH APRIL FIGURE 73.—Data collection platform, Mount Baker, Wash. The FIGURE 74.—Graph of seismic activity recorded by a data diameter of the Plexiglas-covered antenna is 1.2 m. collection platform at Volcan Fuego, Guatemala. DYNAMIC ENVIRONMENTAL PHENOMENA IN SOUTHWESTERN ICELAND By Richard S. Williams, Jr., U.S. Geological Survey he ERTS image mosaic in figure 75 shows a part of west-central, and Tsouthwestern Iceland, an island republic with a relatively small but rapid- ly growing population of 213,070 (Dec. 1, 1973) in an area of 103,000 kmz, or a population density of about 2 persons per km2. Iceland, because of its cool climate, low population density, and paucity of natural resources, has early recognized the potential value of ERTS imagery and the ERTS data collection system to provide at low cost and in near real time certain types of dynamic environmental data, such as variable snow cover, changes in the area of glaciers, and seasonal changes in grasslands. Because Icelanders depend on the surrounding seas for fish and crustaceans and on the limited area of arable land for agricultural products. their economic well-being is greatly determined by their natural environment. Understanding and recognizing changes in, and redirecting human and capital resources in response to, the often capricious nature of the natural environment of Iceland have important economic and social implications (Williams and others, 1973a and 1973b). ERTS imagery of Iceland provides the basis for the study of several dif— ferent geological and geophysical phenomena that relate in an important way to the natural resources of Iceland (Williams, 1972). Within the area shown by the late summer color composite ERTS—l image mosaic live the majority of the inhabitants of Iceland. More than half the population lives in and around the capital city of Reykjavik at 1. The rich grasslands and cultivated areas (tuns) in the lower Thjérsa valley near the coast at 2 and the diminution of vegetation towards the less hospitable interior can be clearly seen. Besides the cultivated and grassland areas, the variations in hues of red permit the mapping of reclaimed land, dwarf forests, and lichen-covered basalts. Barren lands are distinctive by their dark-gray tones and the absence of red colors that indicate a lack of vegetation. Iceland sits astride the Mid-Atlantic Ridge and is one of the most active areas of volCanism in the world. Within the last 12 yr Iceland has had four volcanic eruptions: Askja in 1961, Surtesy in 1963—67, Hekla in 1970, and Heimaey in 1973. The effects of three of these volcanic eruptions are visible on figure 75. Surtesy at 3 is the small (2.5km?) volcanic island off the south coast. Heimaey at 4, an island to the northeast in the same archipelago, was the scene of an extremely damaging volcanic eruption in early 1973. Nearly half the fishing port of Vestmannaeyjar was destroyed or damaged (Williams 109 SO I UNDISZ I I SO I 50382 IDW I nmoz LI 8 I 8 3 6 one I NNOE | IDS I 50782 ISO I (0—0: IDS I (ONO: IWG73 C WS-ZS/WIS-IB N DES;22/ml9-% H83 5 R SLN EL38 F1218] 281-5483-R-I-N-D-2L MSFI ERTS E-1392-l2185 0| mesa-30 Im22-m Ham-eel WG-ml Im73 C P64-8‘Vm28-32 N DB4-81/w28-2l PSS 7 R SLN EL37 FIZISS ZN-S‘Isa-fi-I-N-D-IL NEH ER 8 E-l392-I219l 81 APPROXIMATE SCALE 10 20 30 MILES 10 0 10 20 30KILOMETERS FIGURE 75.—-Annotated color composite ERTS—1 image mosaic of west-central and southwestern Iceland (1392—12185 and 1392—12191). 2, Applications to Geology and Geophysics 111 and Moore, 1973). The new land area on the east side of Heimaey can be seen. The ash-fall pattern at 5 and new lava flows at 6 from the 1970 vol- canic eruption from the famous Hekla Volcano are evident. The 1970 ash fall, containing high concentrations of fluorides, contaminated grasslands that were grazed by sheep. At least 7,000 head were lost in the area because of fluoride poisoning. Several glaciological features are also prominent. The glacier-margin lake, Hvitarvatn 7, is distinctive with its powder—blue color characteristic of tur- bidity caused by glacial sediment. The snowline can be delineated on the Hofsjokull 8, Langjokull 9, Myrdalsjokull 10, and Eyjafjallajokull 11 ice- caps. Note the absence of vegetation at 12 from an area where one of the out- let glaciers of ‘Hofsjokull has receded. A prominent nunatak at 13 can be seen in the center of Langjokull. The snow-capped shield volcano, Skjaldbreidur, can be seen at. 14 and tectonic fissures that extend to the southwest. Sediment plumes from the mouths of rivers laden with glacial rock flour are promi- nent, particularly the one at the mouth of Thjérsa 15. The circular caldera form, light-colored rhyolitic rocks, and lighter col- ored altered-ground areas of Iceland’s largest geothermal area, Torfajokull at 16, contrast sharply with the surrounding darker basaltic rocks or glacial deposits derived from such rocks. The altered ground of the Reykjanes geo- thermal area is just barely discernible at 17. A circular pattern of a possible Tertiary central volcano is visible at 18. At 19 a faint line represents a dif- ference in grass conditions resulting from the installation of a fence to con— trol the grazing of sheep in this district. Finally, an engineering project has reversed the flow of water from the solitary outlet of the V-shaped lake, Thorisvatn at 20. This reversal has resulted in sediment-laden water from a glacial river entering the western arm of the lake, and the gradational plume can be clearly delineated. The comprehensive environmental information from this ERTS mosaic contrasts markedly with the line map of the same area (fig. 76). Although such line maps are revised at intervals, there is no way that conventional maps can keep up with or depict such seasonal changes in the grasslands, variations in size of sediment plumes, changes in glaciological phenomena, and other environmental variables. Because of the wide variety of geological and geophysical phenomena that can be observed in Iceland, and because of the clear and direct historical impact of the dynamic natural environment on the country’s natural resources, Iceland has been particularly well suited as an area for experimental studies to establish the operational feasibility of using Earth resources satellite sen- sors and other systems to meet resource inventory and management needs on, a timely and cost-effective basis. Iceland shares with the United States, and with most other countries of the world, a need for accurate and timely in- formation on the status of its natural resources in order to make wise deci- sions about the best use of such resources. ERTS—l provides a first-time capa— bility for the acquisition of many types of environmental information, par- ticularly for data on dynamic environmental phenomena (\Villiams and others, 1974). I 30 KILOMETERS 30 MILES J ACTIVE FAULTS IN THE LOS ANGELES-VENTURA AREA OF SOUTHERN CALIFORNIA By Russell H. Campbell, . U.S. Geological Survey geologic features by combining bands 4, 6, and 7. The annotated map overlay combined with band 5 (fig. 78) shows the system of active faults that traverse the greater Los Angeles area. This single image shows all the area from Ventura to Santa Ana and from east of Lancaster to Grapevine at the southern tip of the San Joaquin Valley. Most of the faults shown have been active historically or in the last 30,- 000 to 40,000 yr. Many features that mark the traces of these faults are emi— nently visible in the image, which offers a striking synoptic view of their re- lations to each other and to landmarks familiar to all inhabitants of the region. In addition to known faults, the annotations indicate the locations of the epicenters of historic earthquakes that are known (or inferred) to have had magnitudes on the Richter scale of 6.0 or greater. This compilation shows that historic earthquakes and fault movements in the region are not limited to the San Andreas Fault and its clearly defined branches. Instead, the area clearly has been affected by Earth strains that have been relieved by move— ment along several faults. The epicenters of earthquakes shown in figure 78 (solid circles) are labeled according to the year in which the earthquake occurred and include: Figure 77 is a color composite ERTS—l image especially made to enhance Year Fault Earthquake Magnitude Remarks 1852 ________ Big Pine _________________________________________ Ground breakage reported. 1857 ________ San Andreas _______ Fort Tejon _________ l8.0 Possibly 10 m of surface offset. 1893 ________ San Gabriel ________ Pico Canyon ______ 16.0 1916 ___________________________ Tejon Pass ________ 16.0 1933 ________ Newport-lnglenook Long Beach ________ 6.3 zone of folds and faults. 1952 ________ White Wolf ________ Kern County _______ 7.7 About 1 m of surface offset. 1971 ________ San Fernando ______ San Fernando ______ 6.6 Maximum offset about 2 m. 1973 ________ Frontal fault system Point Mugu _______ 6.0 of the Transverse Ranges. < FIGURE 76.—Map of part of west-central and southwestern Iceland (part of 1:1,000,000 map of Iceland, Icelandic Surveying Depart- ment, 1971). 113 IQQ ' UIUOZ IOU I lD——l: Oh) I thZ I Iml 81002 114 ERTS—1, A New Window on Our Planet HI 18-00 2|£K3T72 C N34-33/ul 18-24 M N3 -3 FIGURE 77.—Color composite ERTS—1 image of the ulna-3m Nile-OBI ““7'30' l HHS-3W Nile-gl l/Hlle-IS ”SS D SUN EL39 BZI‘B ISG-IZSS-G-I-N-D-ZL MSH RTS E—IOSB'IBOIZ 0| APPROXIMATE SCALE lO 0 10 20 30 MILES LL [1 I 1' '1' i l | l l l I 10 0 10 20 30 KILOMETERS geologic features (1090-18012, bands 4, 6, and 7). greater Los Angeles area of southern California especially made to enhance no I Ohio: I low ‘ 51002 IDS ~ AQDZ 2, Applications to Geology and Geophysics 115 APPROXIMATE SCALE 10 o 10 20 30 MILES l J l l 1 1 1 l l l . I I . l l l 10 o 10 20 30 KILOMETERS FIGURE 78.——Annotated ERTS—1 image of the greater Los Angeles area of southern California showing location of major and minor faults (1018—18010, band 5). Symbols are explained in the text. 116 ERTS—1, A New Window on Our Planet Faults are shown in figure 78 as solid lines where easily Visible on the image, dashed where recognized with some difficulty, and dotted where con- cealed by the ocean. They are listed below along with the symbol used to identify them on the image. Fault Symbol Remarks Benedict Canyon ___________ B.C. Big Pine ______________________ Callequas _________________ C. Chino ____________________ CH. Frazier Mountain- Alamo Mountain _________ F.-A. Thrust faults. Garlock _______________________ Newport-Inglewood _____________ Zone of faults and folds. Oak Ridge _________________ O.R. Thrust fault. Palos Verdes Hills __________ P.V. Pine Mountain _____________ P.M. Pleito _____________________ P. Red Mountain ______________ R.M. San Andreas ___________________ San Cayetano ______________ S.C. Thrust fault. San Fernando __________________ Do. San Gabriel ________________ ____ San Jacinto ________________ SJ. Historically the most active of the northwest- trending right-lateral faults south of the Transverse Ranges. Santa Rosa _________________ S.R. Santa Susana _______________ S.S. Thrust fault. Santa Ynez ________________ S.Y. Whittier ___________________ W. White Wolf ________; _______ ____ The following faults, also shown in figure 7 8, are segments of the south frontal fault system of the Transverse Ranges province: Fault Symbol Malibu Coast __________ M.C. Raymond Hill __________ R.H. Santa Monica __________ S.M. Sierra Madre ___________ Sa.M. ENVIRONMENTAL GEOLOGY OF THE CENTRAL GULF OF ALASKA COAST By Austin Post, US. Geological Survey the rugged Chugach Mountains on the left, the Bering Glacier dominates the right side, and Cape St. Elias juts into the Pacific Ocean on the south end of Kayak Island. The village of Yakataga is near the right margin of the image, and the town of Cordova is just off the image to the left. When this image was taken on Oct. 24, 1973, cold air from interior Alaska was sweeping down the Copper River valley, picking up dust from sandbars, and blowing it more than 40 km out over the ocean. Large glaciers that flow from lateral valleys and terminate in the Copper River valley are hidden under the dust pall. The Copper River valley is one of the few available low-level routes to the interior of Alaska from the coast. More than 60 yr ago, the river became famous during the construction of the Copper River and Northwestern Rail- road to provide access to the rich Kennicott Mining District. The railroad, extremely expensive to construct and maintain, crossed the Copper River three times, one of these on a $1,000,000 steel bridge located where the Childs Glacier on the west side of the river and the Miles Glacier on the east side terminated directly into the river. Just to the north, the tracks had to be laid on the stagnant, marginal ice of Allen Glacier, which also reached the river’s edge, forming Baird Canyon. The railroad was abandoned in 1938 after the most accessible ore was ex- hausted. Using the same route and many of the same bridges, engineers were constructing a new highway until the 1964 Alaska earthquake abruptly halted progress by destroying most of the new bridges and severely damaging two of the largest old steel railway bridges. Construction of the highway has now resumed with replacement of bridges in the Copper River delta area. This part of the Alaskan Coast is seismically very active and has been raised repeatedly in recent centuries. Evidence of this can be seen from (1) raised sandbars which now form islands off. the mouth of the Copper River. This area was raised approximately 2 m by the 1964 Alaska earthquake: (2) parallel timbered ridges Visible along the coast on the right side of this View represent former beaches. Raised beaches south and east of the Bering Glacier disappear nder the glacier margin and indicate that the Bering Glacier fronted our-the ocean in the not too distant past. In the ERTS image shown in figure 79, the Copper River valley cuts through 117 (9w ! (Jib—*2 i IW|WOZ lmRW—H—E 00‘le 118 ERTS—1, A New Window on Our Planet lHl45~BG NBBI~BB| ”4144*69 Lll43-BBI ,l » MOUNTAINS” ‘ Miles Gwde‘ Bering Lake lrgl' 1.: III [III 10 FIGURE 79.——Annotated color composite ERTS—1 C .. on, O/ \ Kayak Island l ' Cape St. Elias NH‘l-BOI ‘35 D SUN ELI? HZlS‘l l87-6388-H-l-N-D-2L NFISH ERTS 54458-292954 Bl APPROXIMATE SCALE O 10 20 30 MILES .: I ' I ' 4 l 0 10 20 3O KILOMETERS image of the central Gulf of Alaska coast (1458—20205). ISO l “Lb—E l 08 I OWOZ I900 I IVA—'2 saw I (DUIDZ l 2, Applications to Geology and Geophysics 119 Extensive outwash fans constructed by streams from the Bering Glacier and by the Copper River are also changing the landscape; for instance, former beaches are being covered by the outwash east of the Bering Glacier, and the debris from the Copper River is rapidly changing the outline of the coast. Intertidal zones appear as darker areas along the coast and are par- ticularly visible in shallow areas such as Controller Bay (center). The Bering Glacier is the largest in mainland North America. It heads in a broad ice-filled valley, the lower part of which appears in the top right part of this image. The ice flows down a valley about 10 km wide to the coastal plain, where it spreads out in a semicircular lobe nearly 60 km wide. Down the center of this lobe is an extensive band of medial moraines that are made up of debris swept by the ice from the high mountains. Folded structures in these moraines are faintly visible in this image; in fact, the broad central band of debris is composed of a vast aggregation of parallel ridges that rep- resent about five main medial moraines folded 20 times or more. These struc- tures and the accordianlike folds in the eastern margin of the lobe are caused by periodic surges of this vast glacier that apparently occur about every 20 yr. - Lakes appear dark on the image, and several can be seen. In the upper center, large three-pronged Berg Lakes is dammed by an arm of Bering Glacier. Many lakes formed by glacier ice dams are notorious for sudden re- lease when the ice dams fail, which most often occurs where subglacial chan— nels develop and rapidly enlarge by melting as the water flows through them. Even large lakes can thus be drained in a few hours or, at the most, days. Berg Lakes has not drained for many years, but it potentially could devastate the Bering River valley should the ice dam fail. At the present time, the ice dam is considered to be unstable, and flooding could occur at any time. ERTS images are particularly useful for determining the extent of snow cover. Figure 79 shows the snow cover as of Oct. 24, 1973. The elevation of the snowline can be determined by comparing the image with contour maps. Some idea of the snow depth can also be derived from the completeness of cover on rough surfaces such as glacier moraines. For instance, the snowline is clearly visible on Bering Glacier, covering about half of the terminal lobe. From the amount of rock visible in the large central medial moraine it is evident that the snow cover at the time of this image is very thin, probably not more than a few centimeters, at these lower altitudes. The surface of the snow in the immense ice-filled valleys has shadings in ERTS images that are not apparent from the ground or even on most aerial photography. These shadings evidently represent subtle changes in slope that in turn probably are related to bedrock topography, deeply buried under the slowly flowing ice. In Summary, the synoptic images and repetitive coverage provided by the ERTS system enable geologists, for the first time, to monitor dynamic hydrological, geological, and meteorological phenomena that affect man and his environment. DEBRIS AVALANCHES AT MOUNT BAKER VOLCANO, WASHINGTON By David Frank, US. Geological Survey Baker, Wash, is shown in ERTS images (figs. 80, 81) taken Sept. 16, 1973. The avalanche occurred sometime during Aug. 20—21, 1973. Mount Baker is a quiescent stratovolcano composed largely of andesitic lava flows and breccias (Coombs, 1939). Every 2 to 4 yr during recent decades, snow, ice, and hydrothermally altered rock have avalanched from the Sherman Crater rim, south of the mountain summit. The avalanches have flowed 2.0 to 2.6 km eastward, a distance just short of the Boulder Glacier terminus. A major factor in the avalanche occurrence is geothermal emission and subsequent water saturation of the ground beneath the normally heavy snow- pack (Frank and others, 1975). Within 50 m of the avalanche source is a zone of very active fumaroles, warm ground and thermal springs that cur- rently are causing extensive hydrothermal alteration of rock to clay-rich soil. Avalanches will likely continue to occur as long as the current level of heat emission is maintained. There is at this time no evidence to indicate that fumarole activity is declining; it has been known to exist since the time of the last eruptions which probably occurred in the mid-1800’s (Davidson, 1885). Temperatures in fumaroles on Mount Baker are currently being moni- tored using an ERTS DCP. The ERTS image strikingly shows the significance of recurrent mass movement from the volcano. Melt water from Boulder Glacier flows down Boulder Creek (dashed line) and into two large hydroelectric reservoirs— Baker Lake and Lake Shannon. From there the water continues on to the heavily farmed Skagit River valley and finally to more highly populated areas bordering Puget Sound. Although those avalanches that have been observed have not passed the glacier terminus, it is not unlikely that, as hy— drothermal alteration continues, increasing amounts of rock will be contained in future avalanches. Larger avalanches, along with the possible combination of glacier outburst floods, could probably reach the lower Boulder valley. This dangerous potential is of particular importance because of the possible impact on the reservoirs of the lower valley. An indication of the extent of past mass movement in Boulder valley is the large lobate alluvial fan that protrudes into Baker Lake. In addition to normal stream deposits, this fan contains a sequence of postglacial lahars (debris flows or mudflows) from Mount Baker (J. Hyde, US. Geological Survey, written commun., 1974). The most recent lahar lies on the surface and likely occurred within the past few hundred years. The cause of the recent lahars from Mount Baker is not pres- ently known, but it is significant that such activity apparently has been com- mon in the recent past. T he latest in a series of debris avalanches down Boulder Glacier on Mount 120 2, Applications to Geology and Geophysics 121 HIZZ-OOI ma-aeuum-ea “Mmini Baku APPROXiMATE SCALE 10 10 20 30 MILES 30 KILOMETERS 10 o 10 FIGURE 80.—Annotated color composite ERTS—‘l image of the Mount Baker area of Washington (1420-18303). 122 —fi* ERTS—1, A New Window on Our Planet APPROXIMATE SCALE 1 O 1 2 3 4 MILES 1 O 1 2 3 4 KILOMETERS I STRUCTURAL FEATURES RELATED TO EARTHQUAKES IN MANAGUA, NICARAGUA, AND CORDOBA, MEXICO By William D. Carter, US. Geological Survey, and Jack N. Rinker, U.S. Army Corps of Engineers the life of ERTS—l. The first was the Managua, Nicaragua, earthquake of Dec. 23, 1972, which had a magnitude of 5.6 on the Richter scale. More than an estimated 11,000 persons died, and most of the Nicaraguan capital was devastated; property damage was estimated to be more than $0.5 billion (Brown and others, 1973). The second earthquake, having a magnitude of 7.0 on the Richter scale, occurred on Aug. 28, 1973, about 240 km southeast of Mexico City. Although deaths (500 persons) and property damage were less severe than at Managua, buildings collapsed and numerous fires caused by short circuits occurred in six Mexican cities—Ciudad Serdan, Orizaba, Cordoba, Puebla, Tehuacan, and Mexico City (Lomnitz, 1973). Quick action by the ERTS—l control and command center at the NASA Goddard Space Flight Center made it possible for ERTS to collect data over Managua on Dec. 24, 1972, the day after the earthquake. Figures 82 and 83 show the area of western Nicaragua. The Gulf of Fonseca and Honduras are in the upper left. Lake Managua is in the lower right corner, and Managua is under clouds southeast of the Chiltepe Peninsula that is marked by two crater lakes. Volcanic cones, many of which are often active, can be seen in the Cordillera Los Marrabios. Most are in a rather straight, narrow band 15 to 30 km from the coast. Band 7 images were most useful in studying the linear features and show the structural relationship of the Managua area to the surrounding region. The synoptic images give an insight on the directional trends of fractures and faults in the region that might be found during detailed studies of the geology of the city area (Carter and Eaton, 1973). The images also indicate that the volcanoes east of Managua were not actively emit- ting clouds of steam, ash, lava, or other products. The earthquake area was overflown by a NASA aircraft within 10 days after the event, and excellent detailed aerial photography was provided for study and fieldwork by Nic- araguan and US. Geological Survey geologists. These studies indicated that the movement during the earthquake took place along fracture systems trend- ing N. 25° to 45° E. During September 1973, ERTS—l data were collected on five different days over the area of the Mexican earthquake of late August. Of eight images T wo major earthquakes have occurred in the Western Hemisphere during 123 law I (0‘02 I00 I w~oz [MGM—Oz 124 ERTS—1, A New Window on Our Planet APPROXIMATE SCALE 0 10 20 30 MILES l 1 I I l I I I I ' I ' I I I I 0 10 20 30 KILOMETERS FIGURE 82.——Color composite ERTS—1 image of the Managua area of Nicaragua (1154—15385). Oh) I (0—02 I IOOIw—OZ WIN—02' 2, Applications to Geology and Geophysics 125 collected, five had 50 percent or more cloud cover and were therefore only mar- ginally useful for analysis. Three, however, had 25 percent or less cloud cover and were useful in defining regional structural features that could contribute to seismic activity. Unfortunately, the areas most affected by the 1973 earth- quake were in the cloudy regions. Interpretation of the images indicates that a strong set of northwest- trending linear features extends from Presa Miguel Aleman through Cordoba and also in the Tehuacan Valley to the west, along which earthquake activity could take place. Lomnitz (1973) stated that the focus of the event was lo— cated at a depth of 84 km under the western edge of the Veracruz coastal plain, a location that coincides with the Cérdoba lineament. In both cases cited, it was possible to define the regional structural pat— tern and to determine areas where detailed ground studies might be fruitful. It was not, however, possible to define small areas where physical damage had occurred. 13 ”00’ 12°30’ 25 KILOMETERS 25 MILES 87°30’ 87°00' 86°30’ FIGURE 83,—Map of the earthquake area in Nicaragua plotted on part of ERTS-1 image 1154—15385, band 7. REFERENCES Ahmed, Waheeduddin, Khan, S. N., and Schmidt, R. G., 1972, Geology and copper mineralization of the Saindak quadrangle, Chagai District, West Pakistan: U.S. Geol. Survey Prof. Paper 716A, p. A1—A21. Brockmann, Carlos, 1974, Earth Resources Technology Satellite Data Collec— tion Project, ERTS—BOLIVIA: NASA Goddard Space Flight Center, Sym- posium on the Earth Resources Technology Satellite—1, 3d, Washington, DC, Dec. 1973, Proc., v. 1, sec. A, p. 559—577. Brown, R. D. Jr., Ward, P. L., and Plafker, George, 1973, Geologic and seismo- logic aspects of the Managua, Nicaragua, earthquakes of December 23, 1972: US. Geol. Survey Prof. Paper 838, 34 p. Carter, W. D., and Eaton, G. P., 1973, ERTS—1 image contributes to under- standing of geologic structures related to Managua earthquake, 1972: NASA Goddard Space Flight Center, Symposium on Significant Results Obtained from the Earth Resources Technology Satellite—1, 2d, New Carrollton, Md., Mar. 1973, Proc., v. 1, sec. A, p. 459—471. Coombs, H. A., 1939, Mt. Baker, a cascade volcano: Geol. Soc. America Bull., v. 50, p. 1,493—1,510. Davidson, George, 1885, Recent volcanic activity in the United States; erup- tion of Mount Baker: Science, v.6, no. 138, p. 362. Fischer, W. A., and Lathram, E. H., 1973, Concealed structures in Arctic Alaska identified on ERTS—1 imagery: Oil and Gas Jour., v. 71, p. 97— 102. Frank, David, Post, Austin, and Friedman, J. D., 1975, Recurrent geothermally induced debris avalanches on Boulder Glacier, Mount Baker, Washing- ton: U.S. Geol. Survey Jour. Research, v.3, no. 1, p. 77—87. Freund, R., 1970, The geometry of faulting in the Galilee: Israel Jour. Earth Sci., v. 19, p. 117—140. Girdler, R. W., 1962, Initiation of continental drift: Nature, v. 194, no. 4828, p. 521—524. 1972, African poles of rotation: comments on Earth sciences: Geo- physics, v. 2, no. 5, p. 131—138. Goetz, A. F. H., Billingsley, F. C., Elston, Donald, Lucchitta, lvo, and Shoe- maker, E. M., 1973, Preliminary geologic investigations in the Colorado Plateau using enhanced ERTS images: NASA Goddard Space Flight Center, Symposium on Significant Results Obtained from the Earth Resources Technology Satellite—1, 2d, New Carrollton, Md., Mar. 1973, Proc., v. 1, sec. A, p. 403—411. Grantz, Arthur, Hanna, W.’ F., Holmes, M. L., and Creager, J. S., 1970, Recon- naissance geology of Chukchi Sea as determined by acoustic and mag- netic profiling [abs.]: Am. Assoc. Petroleum Geologists Bull., v. 54, no. 12, p. 2,483. Jennings, C. W., and Strand, R. G., 1958, Geologic map of California, Santa Cruz sheet: California Div. Mines and Geology. 126 2. Applications to Geology and Geophysics 127 Lathram, E. H., 1973, Geologic application of ERTS imagery in Alaska [abs.]: NASA Goddard Space Flight Center, ERTS Symposium, 3d, Washington, DC, Dec. 1973, Abs., p. 39. Lathram, E. H., Tailleur, l. L., Patton, W. W., Jr., and Fischer, W. A., 1973, Preliminary geologic application of ERTS—1 imagery in Alaska: NASA Goddard Space Flight Center, Symposium on Significant Results Ob- tained from the Earth Resources Technology Satellite—1, 2d, New Car- rollton, Md., Mar. 1973, Proc., v. 1, sec. A, p. 257—261. Le Pichon, Xavier, and Heirtzler, J. R., 1968, Magnetic anomalies in the Indian Ocean and sea-floor spreading: Jour. Geophys. Research, v. 73, no. 6, p. 2101—2117. Lomnitz, Cinna, 1973, The Puebla-Veracruz, Mexico, earthquake of August 28, 1973: U.S. Geol. Survey Earthquake lnf. Bull., v. 5, no. 6, p. 19—22. McKee, E. D., Breed, C. S., and Harris, L. F., 1973, A study of morphology, provenance, and movement of desert sand seas in Africa, Asia, and Australia: NASA Goddard Space Flight Center, Symposium on Signifi- cant Results Obtained from the Earth Resources Technology Satellite—1, 2d, New Carrollton, Md., Mar. 1973, Proc., v. 1, sec. A, p. 291—303. McKee, E. D., and Breed, C. S., 1974, An investigation of major sand seas in desert areas throughout the world: NASA Goddard Space Flight Center, Symposium on the Earth Resources Technology Satellite—1, 3d, Wash- ington, D.C., Dec. 1973, Proc., v. 1, sec. A, p. 665—679. McKenzie, D. P., Davies, D., and Molnar, Peter, 1970, Plate tectonics of the Red Sea and East Africa: Nature, v. 226, p. 243—248. Morrison, R. B., and Hallberg, G. R., 1973, Mapping Quaternary landforms and deposits in the Midwest and Great Plains by means of ERTS—1 multispectral imagery: NASA Goddard Space Flight Center, Symposium on Significant Results Obtained from the Earth Resources Technology Satellite—1, 2d, New Carrollton, Md., Mar. 1973, Proc., v. 1, sec. A, p. 353—361. Rowan, L. C., Wetlaufer, P. H., Goetz, A. F. H., Billingsley, F. C., and Stewart, J. H., 1974, Discrimination of rock types and detection of hydrothermal— ly altered areas in south-central Nevada: US Geol. Survey Prof. Paper 883, 35 p. Schmidt, R. G., 1973, Use of ERTS-1 images in the search for porphyry cop- per deposits in Pakistan—Baluchistan: NASA Goddard Space Flight Center, Symposium on Significant Results Obtained from the Earth Resources Technology Satellite—1, 2d, New Carrollton, Md., Mar. 1973, Proc., v. 1, sec. A, p. 387—294. Stoertz, G. E., and Carter, W. D., 1973, Hydrogeology of closed basins and deserts of South America, ERTS—1 interpretations: NASA Goddard Space Flight Center, Symposium on Significant Results Obtained from the Earth Resources Technology Satellite—1, 2d, New Carrollton, Md., Mar. 1973, Proc., v. 1, sec. A, p. 695—705. Tailleur, l. L., and Brosgé, W. P., 1970, Tectonic history of northern Alaska, in Adkison, W. L., and Brosgé, M. M., eds., Proceedings of geological seminar on the North Slope of Alaska: Los Angeles, Pacific Sec., Am. Assoc. Petroleum Geologists, p. E1—E19. 128 ERTS—1, A New Window on Our Planet von Gaertner, H.-R., and Walther, H. W., coordinators, 1971, lnternat. geo- logic map of Europe: Hannover, Germany, Bundesanstalt fiir Bodenfor- schung and UNESCO, lnternat. Geol. Cong., Comm. for the lnternat. Geol. Map of the World, scale 125,000,000, 2 sheets. Ward, P. L., Eaton, J. P., Endo, E. T., Harlow, D. H., Marquez, Daniel, and Allen, Rex, 1973, Establishment, test and evaluation of a prototype vol- cano surveillance system: NASA Goddard Space Flight Center, Symposi- um on Significant Results Obtained from the Earth Resources Technology Satellite—1, 2d, New Carrollton, Md., Mar. 1973, Proc., v. 1, sec. A, p. 305—315. Ward, P. L., Endo, E. T., Harlow, D. H., Allen, Rex, and Eaton, J. P., 1974, A new method for monitoring global volcanic activity: NASA Goddard Space Flight Center, Symposium on the Earth Resources Technology Satellite—1, 3d, Washington, DC, Dec. 1973, Proc., v. 1, sec. A, p. 681—689. Williams, R. 5., Jr., 1972, Satellite geological and geophysical remote sensing of lceland [abs.]: lnternat. Symposium on Remote Sensing of Environ- ment, 8th, Ann Arbor, Mich., 1972, Proc., p. 1,465—1,466. Williams, R. 5., Jr., and Moore, J. G., 1973, Iceland chills a lava flow: Geo— times, v. 18, no. 8, p. 14—17. Williams, R. 5., Jr.; Bodvarsson, Agflst; Fridriksson, Sturla; Palmason, Gud- mundur; Rist, Sigurjén; Sigtryggsson, Hlynur; Thorarinsson, Sigurdur; and Thorsteinsson, lngvi, 1973, Satellite geological and geophysical remote sensing of lceland—preliminary results from analysis of M55 imagery: NASA Goddard Space Flight Center, Symposium on Significant Results Obtained from the Earth Resources Technology Satellite—1, 2d, New Carrollton, Md., Mar. 1973, Proc., v. 1, sec. A, p. 317—327. Williams, R. 5., Jr., Bodvarsson, AgUst; Fridriksson, Sturla; Palmason, Gud- mundur; Rist, Sigurjon; Sigtryggsson, Hlynur; Saemundsson, Kristjan; Thorarinsson, Sigurdur; and Thorsteinson, lngvi, 1973b, lceland—pre- liminary results of geologic, hydrologic, oceanographic, and agricultural studies with ERTS—1 imagery: Am. Soc. Photogrammetry, Symposium on Management and Utilization of Remote Sensing Data, Sioux Falls, 5. Dak., 1973, Proc., p. 17—35. Williams, R. 5., Jr.; Bodvarsson, Agust; Fridriksson, Sturla; Pa’lmason, Gud- mundur; Rist, Sigurjén; Sigtryggsson, Hlynur; Saemundsson, Kristjan; Thorarinsson, Sigurdur; and Thorsteinsson, lngvi, 1974, Environmental studies of lceland with ERTS—1 imagery: lnternat. Symposium on Re- mote Sensing of Environment, 9th, Ann Arbor, Mich., 1974, Proc., v. 1, p. 31—81. Wilson, E. D., Moore, R. T., and Cooper, J. R., 1969, Geologic map of Arizona: Tucson, Arizona, Arizona Bur. Mines. CHAPTER 3. APPLICATIONS TO WATER RESOURCES ince its launch late in July 1972, a wealth of hydro- S logic information has been derived from ERTS— 1. Before describing specific data obtained by ERTS and some of the significant observations and applications made, it will be useful to examine the role of ERTS in determining hydrological conditions over any area, observing changes in storage or conditions, and providing quantitative inputs for hydrological models. Hydrology is a science of dynamic phenomena. It is concerned with the flux of water from the atmosphere to the Earth’s surface; overland storage and runoff; infiltration, subsurface storage, movement, and even- tual discharge; and return to the atmosphere by means of evaporation and transpiration. Hydrology is con- cerned also with water quality and changes in quality occasioned by its contact with the environment and man’s effect on it. A major goal of remote sensing in hydrology, therefore, is to observe and measure dy- namic conditions of water quantity and quality. Water interacts with the Earth’s atmosphere, soil, vegetation, physiography, and geology, and it pro- foundly affects the works of man. Hence, remote- sensing techniques can be used also to assess hydrologic conditions by indirect analysis of water along with other environmental parameters. The work of Higer, Coker, and Cordes in development of an ecological model in Florida (p. 150) represents an important milestone in using satellite data for environmental monitoring. The investigators have devised a means of predicting success or failure of wood stork rookeries as one of the indices of hydrologic conditions in the Everglades National Park. Parameters upon which the predictions are based are water—level measurements that can be relayed by the ERTS data collection sys- tem, the spatial distribution of water that can be meas- ured on ERTS images, and the population density of small aquatic animals per unit area collected in quan- titative traps. The very fact that the quantity and, generally, the INTRODUCTION By Morris Deutsch, US. Geological Survey quality of water in a given area are constantly chang- ing requires that repetitive data be collected to monitor changes. Although ERTS cannot continuously meas- ure the discharge of streams or their quality, its 18- day repeat cycle is ideal for determining changing hydrological conditions caused by climate, seasonal effects, or man’s activities. The design of a water-man- agement model for the Everglades, employing quanti- tative inputs for areas of water surface from band 7 and water-stage data relayed by ERTS from surface recorders has stimulated use of satellite data for opera- tional water management for Florida. In the Pacific Northwest and other areas through— out the world, eflicient regulation of reservoirs fed by melting snow is vital for generation of hydroelectric power, irrigation withdrawals, domestic water supply, waste assimilation, and maintenance of fisheries. By studying successive ERTS images and related ground data, Krimmel and Meier (p. 173), have deter- mined the rate of change of snow-covered areas and estimated amounts of water stored as snow. ERTS data have thus provided a basis for improving pre- dictions about the subsequent availability of water from snowmelt. The ERTS data—collection-system experiment by Paulson (p. 132) for the Delaware River basin is being used as the framework for an operational sys- tem. Hydrologic data relayed by the satellite and images are being provided to the Delaware River Basin Commission as a basis for improved water man- agement. Timely satellite data can assist agencies in water-management decisions concerning reservoir re- leases, water-plant intake for quality control, and municipal and sewage effluent release. Future satellite data-collection systems will enable the U.S. Geological Survey to more efficiently operate the national hydro— logic data network, which includes about 15,000 in- strumented stations where streamflow, water level, water quality, and related water data are collected. Before the launch of ERTS, the hydrologic scien— 129 130 ERTS—1, A New Window on Our Planet tists did not expect that existing flood-applications capability would be greatly expanded by the ERTS data. Since its launch, however, ERTS has provided data, as described herein, permitting observations and analyses regarding floods far beyond those anticipated. A large synoptic view of flooding along the entire Mis- sissippi River valley below St. Louis was provided on only 16 images collected on two dates in 1973 during a total period of about 7 min. By color combining pre— flood coverage with flood coverage, a color-coded dis- play was produced in which flooded area was auto- matically separated from areas normally covered by water. The unique water-detection capability of band 7 has made it possible for the first time to delineate areas from which flood waters have receded inasmuch as the flood waters leave a spectral signature on the surface. This capability is tremendously significant since it is not necessary to photograph or image the flood in progress. Imaging a flood in progress, of course, is of limited value because river valley reaches downstream from the peak have not yet experienced maximum inundation. Water in streams less than a few meters to tens of meters wide, or lakes less than a few hectares in areal extent, cannot be detected by ERTS. The presence of water in the soil or in vegetation along the stream val- ley, however, is readily detectable. Indeed, a highly significant fact, vividly portrayed by ERTS color composite images of much of the United States and Canada, is the immense amount of water transpired to the atmosphere by vegetation. The vast extent of the vegetation is indicated by the almost totally red com— posite summer images covering large areas of the United States. On standard color composite images (bands 4, 5, and 7), vegetation is red, and the denser vegetation is depicted by deeper tones of red. The hy- drologist thus has at hand a powerful tool for deter- mining the percentage of the water budget involved in transpiration and the duration of the period of tran- spiration for the predominant classes of vegetation. Turner (p. 246) has shown, for example, changes in the patterns of dense plant growth. This type of information will be useful in determining a variety of hydrobiological conditions, including range readiness for grazing by livestock. An estimated 90 percent of the freshwater resources of the Earth consists of ground water stored in re- gional aquifers. Data from ERTS contain much infor- mation about the distribution of ground water and the extent of its utilization (Deutsch, 1974). Precise delineation of geologic formations—especiaL ly the upper or shallow units that, in most areas, form the best aquifers—is a requisite for hydrogeologic in— vestigations. ERTS images of areas underlain by gla- cial, alluvial, eolian, and other unconsolidated sedi- ments often provide an excellent basis for delineation of shallow aquifers. Indurated sedimentary rocks, especially limestone and sandstone formations, com- prise important and extensive aquifers in many re- gions of the world. In some instances, ERTS data can be used directly to determine their boundaries, re- charge areas, and discharge areas, including the loca- tion of springs. The imagery is potentially useful in depicting the detailed surface structures of crystalline rocks in igneous and metamorphic terranes, where ground water commonly is stored in openings along joints and fractures. Most applications of remotely sensed data deal with surface phenomena inasmuch as it is the surface that is being imaged by ERTS and other satellites or air- craft. The hydrogeologist, however, commonly infers subsurface hydrological conditions from such surface indicators as areal geological features and structures, as described by Moore and Hollyday (p. 164). Soils and soil-moisture anomalies, vegetative types and dis- tribution, discontinuous ice cover on streams, difl'eren- tial snowmelt, and springs that are detected by ERTS may also be indicative of ground water. Accordingly, it is believed that remotely sensed data, and particular- ly the synoptic, worldwide, and repetitive data col- lected by ERTS—1, can be eflectively used as a tool for the exploration of ground water and for the monitor- ing and management of ground-water resources in se- lected instances. Evidence of irrigation from nonsurface sources on ERT S data also indicates the presence and distribu— tion of ground water, and the repetitive data can pro- vide a basis for estimating ground-water use. Much has been written about the applications of ERTS for water quality, and indeed ERTS has made important contributions to that field. ERTS data can be used to reveal regional or local distribution of ano- malies in water quality due to difference in turbidity attributable to varying concentrations of sediment or other particulate matter in the water. The chemical and physical quality of the water can be analyzed in the laboratory from samples collected on the ground. In the Delaware River basin and else- where in the United States, water-quality parameters are measured and recorded continuously at numerous points by automated monitors, and the data are relayed via the ERTS data collection system. The data pro- vided by ERTS are then used to extrapolate areally the point-quality data. Thus the sources, movement, and fate of pollutants, suspended sediments, or waters from different sources are determined. Significant ex- amples of the use of ERTS data for water—quality ap- plications have been described by Stortz and Sydor (1974), who mapped turbidity currents in Lake Su- perior, and by Lind, Henson, and Pelton (1973), who used turbidity as an indicator of water pollution and its source and fate in Lake Champlain. The latter study is especially significant because the data were used in litigation that the State of Vermont initiated against the alleged pollutors. ERTS data has greatly improved scientists’ knowl- edge of glaciers because of the synoptic and repetitive data from generally inaccessible terrain. Krimmel, Post, and Meier (p. 178) in their study of surging and nonsurging glaciers in the Pamir Mountains of the U.S.S.R. suggest a practical and valuable applica- tion for the ERTS data: glacier-surge warnings. Glaciologists now have a means of locating and map- ping hazardous glacial conditions and providing warn- ings as to when glacier surges and surge-related floods can be expected. In their ERTS study of the dynamics of the Lowell and Tweedsmuir Glaciers in Canada, Post, Meier, and Mayo (p. 180) have shown how river flow may be- come blocked and form lakes or become impeded and disrupt navigation. The ERTS imagery can be used to produce maps and quantitative displacement data for large surging glaciers far more quickly and effi— ciently than by use of aerial photographic techniques or ground surveys. While an understanding of dynamic glacial proc- esses is of great scientific interest, Meier, in his study of the glaciers in the Mount McKinley massif (p. 185), points out an important practical value of these ERTS-aided studies: Glaciers are one of the few sources of unexploited water supply, and an improved understanding of glacial processes, along with current information on their condition, can aid in their even- tual development for water supply. Williams points out that ERTS permits a glacier to be studied as a total system (p. 188) because ERTS imagery provides regional views of glaciers and ice- caps from a time-lapse viewpoint. Vatnajokull icecap, the largest icecap in Iceland, has been imaged several times, and each time new knowledge of the dynamics of this icecap has been gained. A surge in one outlet glacier, rapid motion of another outlet glacier, and changes in glacier margin lakes have been observed in ERTS images in less than a year’s time. MacDonald’s work with ERTS images of Antarc- tica, an extremely remote and inhospitable area, has been profound (p. 194). The regional synoptic View of ERTS imagery and the repetitive coverage 131 3, Applications to Water Resources have already contributed substantial new scientific knowledge about Antarctica, particularly on the dy- namics of the coastal glaciers and ice shelves. Morrison and White, in their analysis of ERTS data covering the 1973 Mississippi River floods (p. 196), related tone differences in the images to standing- water areas, wet areas, and well—drained soils. They found ERTS data to be of value in determining the effects of physiographic and manmade levees on the distribution of flood waters. They observed also that ERTS need not obtain data at the time of the flood crest to determine inundated areas because of the fact that floods have their effects on the surface reflectance conditions that are detectable for a week or more after the peak has passed on down the valley. Repetitive ERTS imagery, they conclude, can be used to assess the adequacy of existing flood-control systems, such as reservoirs, levees, and channelization. Experimentation with the data collection system on ERTS by Kahan (p. 214) has shown its potential value for monitoring cloud-seeding conditions. Under Project Skywater, the Bureau of Reclamation weather- modification research program, seven data collection platforms have been installed in areas of severe en- vironmental conditions and have proven to be very reliable and cost effective. Temperature, humidity, in- solation, ice riming, wind direction, wind speed, snow- water content, and streamflow data are transmitted via ERTS and the Goddard Space Flight Center to Skywater’s environmental computer network for trans- lation into measured units. Shown and Owen have employed ERTS data for mapping surficial geology, topography type and qual- ity of vegetation, and land use that influence runofl’ and sediment yield (p. 134). In arid and semiarid regions, the combined use of ERTS imagery and re- connaissance methods can be a useful tool for estimat- ing streamflow and sediment discharge where data are scarce or inadequate. ERTS imagery can be used ef- fectively to aid in the interpretation of the hydrologic characteristics of large drainage basins. The U.S. Army Corps of Engineers is using ERTS imagery in an operational program for inspection of surface-water bodies with an area of 4 ha (40,000 In?) or larger (J arman, 1973; Graybeal and others, 1973, 1974). In August 1972 the House of Representatives passed a bill (HR. 15951) that required the Corps of Engineers to make a national inventory of all dams that impound 60,000 In3 of water or that have a height of 2 m or more; repetitive coverage provided by ERTS will permit updating of this inventory at fre- quent intervals. WATER RESOURCES IN THE DELAWARE RIVER BASIN By Richard W. Paulson, US. Geological Survey potential operational system for collecting hydrologic data from un— attended field instrumentation (Paulson, 1974). The evaluation, which is being conducted by NASA, the EROS Program of the US. Department of the Interior, the U.S. Geological Survey, and several cooperating water-resources agencies, indicates that it is technically feasible to use Earth-orbiting Satellites as vehicles for collecting data from field instruments and that there is poten- tial application for operational satellite data-relay systems. The ERTS experi- ment described here is a simulation of an operational satellite data-relay and data-processing system. The ERTS DCS is a communications system that consists of three ele- ments: (1) a small low-power battery-operated radio transmitter attached to a stream gage or a level, temperature, or quality meter; (2) a relay transponder aboard ERTS; and (3) ground-receiver sites. The polar-orbiting ERTS makes 14 orbits of the Earth daily and can relay data from a DCP to a ground- receiver site whenever both are visible from ERTS. This occurs during a brief period of each of the several daily orbits. The DCP transmits a brief data message of 0.04 s duration once every 90 or 180 s. The number of mutually visible periods is primarily a function of geographical position and local ter- rain interference. Two ground-receiver sites, one at the Goddard Space Flight Center in Greenbelt, Md., and one at Goldstone, Calif, provide good coverage for the conterminous 48 States. They allow data from DCP’s in these States to be relayed on 3 to 7 daily orbits during periods lasting as long as 12 to 14 min. The mosaic of ERTS imagery (fig. 84) shows parts of Delaware, Mary- land, New York, Pennsylvania, and Connecticut, all of New Jersey, and most of the Delaware River basin. DCP’s have been installed in the basin on 20 water-resources instruments operated by the US. Geological Survey in co- operation with the Delaware River Basin Commission, the City of Phila— delphia Water Department, and other local, State, and Federal agencies. The instruments are 12 water-quality monitors, 5 stream gages, and 3 ground-water observation wells, and their locations are shown in figure 84; data from them are relayed by ERTS several times daily and are provided in real time to the US. Geological. Survey’s oflice in Harrisburg, Pa. These data are computer processed daily using remote terminal access to the Survey’s computer center in Reston, Va., and are made available to water-resources agencies in the basin. This experiment has verified that it is technically feasible to use the ERTS DCS as an operational tool for collecting data from remotely located water- resources field instruments (Paulson, 1973a,b). T he data collection system (DCS) aboard ERTS—l is being evaluated as a 132 3. Applications to Water Resources 133 UNITED STATES NASA ERTS-l DEPARTMENT as THE INTERIOR NEW JERSEY SATELLITE IMAGE mosAlc GEOLOGICAL SURVEY 7r 5 S , V W'rww—m-ww ‘U it; l fllC Inn-(u all) mam .v m u 3 “mm mm 1mm... .me Imam m: zen: .- mmu m. m mm umm m m- m a w n so u) m. .n so so :4: 547 mm” 1mm...— m_*_—.m.mwm. __ u W ”MVJDm‘vllamu um me: u a m nu IV so: -mln-uxv~mmvml mm... mm I-u-wr—n unnm‘w NEW JERSEY sATELuTE IMAGE Mos/u: 1972 FIGURE 84.——Annotated color composite ERTS—1 mosaic showing data collection platform sites (A) in the Delaware River basin. HYDROLOGY OF THE WIND RIVER BASIN AND ADJACENT AREAS OF WYOMING By Lynn M. Shown and J. Robert Owen, US. Geological Survey the Wind River basin and parts of adjacent basins in central Wyoming. A variety of hydrologic con- ditions resulting from differences in climate, geology, relief, and land use are apparent on the image. Boysen Reservoir is the focal point of the drainage network of the Wind River basin, which is a deep structural depression. Most of the major perennial streams occur in the west half of the basin. The streams are marked along their entire courses by red, which is characteristic in color composite images of vigorously growing vegetation. Streamflow is sustained by 30 to 65 cm or more of annual precipitation in the mountains as opposed to 18 to 30 cm in the mostly ephemeral lower parts of the basin. In the eastern half of the basin, only certain reaches of the streams are perennial. In these reaches, shallow ground water is fed to the streams from permeable upland areas that are under- lain by impermeable clayey siltstone (Whitcomb and Lowry, 1968). The reach of Poison Creek through the Sand Hills is the best example of this; the wider red bands of phraetophytes there indicate ground-water discharge along the streams. The identification of such conditions on a synoptic image of an area or region en- ables a hydrologist, with the aid of topographic maps, to prepare a generalized map of the water-table con- figuration that is helpful in the exploration for small supplies of ground water in the interstream areas (F. N. Visher, oral commun., 1974). , The wide sandy-bottomed ephemeral stream chan- nels in the east half of the basin' are quite evident because of their light color. Thistype of channel indi- cates sandy or gravelly alluvium :that absorbs appre- ciable amounts of the sporadic flood flows and thus diminishes streamflow and sediment discharge :in the downstream direction. _ t l - Variations in surface runoff and" sediment yield in arid and semiarid regions usually correlate with varia- tions in drainage density (Hadley and‘Schumm, 1961) Figure 85, a color composite ERTS—l image, shows or topographic texture, which can be quantified readily ' with small-scale satellite imagery for areas greater than 250 kmz. In the Sand Hills area, the highly per- meable sandy soils absorb much of the scant 18 to 20 cm of annual precipitation, resulting in very little overland flow and, consequently, a low drainage den- sity. This condition contrasts with the high drainage 134 density just north of the Beaver Rim and on the flanks of the Owl Creek and Bighorn Mountains, which indi- cates relatively high surface runoff (Peterson, 1962). The whitish areas south of Badwater Creek, around Boysen Reservoir, and north and west of the Wind River are steep, rugged, highly dissected and sparsely vegetated hills composed of light-colored claystones, siltstones, and sandstones (Keefer, 1965). Runoff and sediment yields from these areas are high, but, because the rocks are very fine textured and because chan- nel vegetation is sparse, the extremely high drainage density of these areas is not apparent on the image. Color composite satellite images can aid greatly in an analysis of the water resources of river basins or other large areas. Because water appears black in these images, rivers, lakes, reservoirs, and large ponds, greater than 150 to 300 m across, depending on con- trast, can be inventoried quickly, and their areas can be estimated so that the amount of water evaporated from them can be computed. Estimates of evapotran- spiration by general vegetation types can be obtained by multiplying the area of each type by an average water—use factor for that type. Forests appear on the image as extremely dark brown areas with reddish highlights in the Wind River, Absaroka, and Green Mountains. The brilliant red areas in the Wind River and Absaroka Mountains are meadows. The patchwork red and yellow areas adjacent to the Wind and Big- horn Rivers are irrigated crops, and the smooth red areas along streams such as the Sweetwater River and upper Badwater Creek are irrigated meadows. Nearly all the remaining area is rangeland, which appears variable in color. These color variations are due to dif- ferent rock types that have been mapped by Love and others (1955) and also to different types and densities of vegetation. The image colors are light where the rocks and soils are eroded and vegetal cover is sparse, and the colors are dark where the rocks and soils are resistant and the cover of vegetation is relatively dense, such as in the Owl Creek Mountains. ERTS imagery thus provides an excellent tool for improving the understanding of hydrologic processes within regional hydrologic systems. Areas for which hydrologic knowledge is deficient and areas where land—use changes may affect the water resources can readily be inventoried using such ERTS imagery. 3, Applications to Water Resources 135 Mean-am ”ma-ea mai-sm IQUIUI‘IQZ $0 ‘ QAQZ I MOUNTAINS iuwvwhflz 8/ C NORA] I 00 l '40—: I00 | wnaz 9 D g 3 B I 09 I (0.302 ISwINDDZ IN IDS-30 WES-OBI LI BSFIB 4! C N43-l8/H188-I7 43-iB/NIBB-i4 PISS 4’ ‘ ‘ IBIB-I’i'ZS‘Mll 82 APPROXIMATE SCALE 0 10 20 30 MILES 10 O 10 20 30 KILOMETERS FIGURE 85.——Annotated color composite ERTS—1 image of the Wind River basin and adjacent areas of Wyoming (1013—17294). IMPROVING ESTIMATES OF STREAM FLOW, CHARACTERISTICS By Este F. H'ollyday and Edward J. PIuhowski, US. Geological Survey and-use data obtained from an ERTS image (fig. '- 86) was used to improve estimates of mean monthly streamflow for July in the Delmarva Peninsula. Information on average streamflow and streamflow variability is needed for the utilization, management, and conservation of our water resources. Historical data on mean daily streamflow, floods, and droughts are used routinely in designing such structures as elec- tricity-generating plants, reservoirs, bridges, and water-supply and sewage-treatment plants. The statis- tical measures used to characterize streamflow are de- termined from continuous flow records extending over ‘ 10 yr or more. Frequently, flow records are not avail- able for a particular point on a stream. The flow char- acteristics at that point, however, may be estimated if regional relationships exist between the streamflow characteristics and the physiographic and climatic characteristics of nearby gaged basins. Assuming that regional relationships may be expressed by usable equations developed from records of gaged basins, it is then possible to characterize streamflow at the ungaged sites by measuring each equation parameter in the basin above the point of interest. As part of a national program of the US. Geological Survey, equations were formulated using multiple re- greSSion techniques. These equations relate as many as 40 streamflow characteristics to selected basin charac- teristics. Gaging stations with at least a 10-yr record of unregulated flow were used in the regression an- alyses. Within}-sele‘ctxedggerror, limits, these equations may be used to‘ lestimatqe'streamflow characteristics at ungaged sites for about 50 regions in the Nation. The ERTS image (fig. 86) contains information on the distribution of forests (brown-red), fields (white, 136 pink, and gray), urban areas (blue-gray), and water (blue-black) . A measure of the relative area of a drain- age basin covered by each of these four land-use cate- gories constitutes a basin characteristic that may be used in estimating streamflow. For example, forest areas can be separated from the other categories by visual interpretation. Automated techniques employing film-density discrimination were used to improve upon the accuracy and uniformity of this separation. The resulting extraction of forest areas (fig. 87) can be measured basin-by-basin using automated techniques and can belchecked by a manual point count. The per- centage of forest cover so measured can be added to the data on basin characteristics used in the streamflow regression analyses. In the equation given in figure 87, the landsuse category Uf (forest) was one of four basin characteris- tics selected by multiple regression analysis as being statistically significant in' defining mean monthly streamflow for July. The other three significant basin characteristics include A' (drainage-basin area), Si (soil infiltration capacity), and I 2,, 2 (24—h, 2-yr-recur- rence rainfall intensity). Other factors in the equation include the regression constant, a, and regression co- efficients, b1, 62, 63, and 64. Addition of Uf in the regres- sion analysis resulted in a 20 percent improvement upon previous estimates of mean monthly streamflow for July. In a previous related study, urban, agriculture, for- est, and water areas determined from ERTS analogous aerial photography were added to the basin character- istics for 39 basins in the Piedmont and Coastal Plain provinces of Maryland and Delaware. Addition of these characteristics reduced the standard error of esti- mate of equations for 12 out of 40 streamflow charac- 3, Applications to Water Resources NEW JERSEX law I COIA’ISZ LI El 7 S “l a 3 El 8 8 I814) I WWW}: MARYLAND I an» I wwmr; INN I (”1.0612 Naive-aw %ZGCT"2 : waszxwms-z: n: NBS-ST/w87S-l7 nee APPROXIMATE SCALE 0 10 20 30 MILES l—J-h—l-H—fi—‘l—i—‘rJ—4 10 0 10 20 3O KILOMETERS FIGURE 86.—Annotated color composite ERTS—1 image of the Delmarva Peninsula area (1079—15133). 138 ERTS—1, A New Window on Our Planet teristics. The standard error of estimate of seven of the equations were reduced more than 10 percent. These results are significant in that a reduced standard error of estimate indicates less variance about the curve of relation, thereby improving predictive capability of the equation. Significant improvement (standard error reduced by more than 10 percent) upon estimates of mean monthly streamflow was computed for June, July, September, AREA MEASUREMENT WITHIN SELECTED DRAINAGE BASINS and November. Other significantly improved stream- flow characteristics included the 7-day, 2-yr—recurrence lOW flows, 3-day, 2-yr-recurrence flood volumes, and estimates of the 50 percentile of flow-duration curves. As a result of using remotely sensed data, estimates of some characteristics of streamflow at ungaged sites have been significantly improved. These improvements will support better utilization, management, and con- servation of our water resources. THEMATIC EXTRACTION OF FORESTED AREAS APPLICATION IN ESTIMATING STREAMFLOW FIGURE 87.—Flow diagram of technique for improving estimates of streamrow characteristics derived from multiple regression equations by using forest data extracted from ERTS—1 image 1079—15133 (fig. 86). layas are almost flat landforms that occupy the P lowest parts of desert basins. Composed of rela- tively homogeneous materials and characterized by a general lack of relief or of vegetation, their micro- relief changes with fluctuations in the level of ground water. Playas are common features of arid landscapes, and consequently they have widespread global distri- bution. Although playas occupy only 6 percent of the land area of Iran, most of the population lives adjacent to them because of the availability of flat land and mod- erate supplies of ground water at relatively shallow depths. The playas have not been fully utilized because of the lack of adequate knowledge concerning the sea- sonal changes in their surface- and ground-water hy- drologies and in the physical properties of their sedi- ments. Most playa investigations have been conducted during the summer when the surficial sediments are dry and have sufficiently high bearing strengths to sup- port men and vehicles, but this practice has limited the understanding of these dynamic landforms. Sixty playas within the interior of Iran have been studied since 1965 (Krinsley, 1968, 1969, 1970, 197 2a,b). These range in area from 25 to 52,825 km2 (Great Kavir) ; 33 playas are smaller than 300 kmz, and, except for the Great Kavir, the largest playa is 4,685 kmz. Visits were made to 22 playas; 20 were observed from low-flying aircraft; and 18 were viewed solely from aerial photographs and from ERTS—l images. The repetitive coverage of ERTS—l is ideally suited to provide seasonal images of the Iranian playas from which changes in the areal extent and morphol- ogy of the surficial materials can be recorded along with contemporaneous or previous field studies of actual surficial conditions. Data derived from the an- alyses of ERTS—l images can provide a rational basis for planning the economic utilization (salt or water extraction and agriculture) and engineering develop- ment (roads and airfields) of these geomorphic fea- tures. MONITORING WATER RESOURCES IN QOM PLAYA, WEST-CENTRAL IRAN By Daniel B. Krinsley, US. Geological Survey Qom Playa, in west-central Iran, is a good example. The playa is the sump for a drainage basin of 86,812 km2 and lies adjacent to the city of Qom and its exten- sive surrounding farmlands and oil resources. During the period of this study, from Sept. 4, 1972, to May 14, 1973, Qom Playa was driest from mid- September to late-September (fig. 88). The playa was almost completely saturated by mid—May (fig. 89) . The period of greatest lake fluctuation occurred in mid- December when the lake area almost tripled and the lake volume increased more than five times (fig. 90). At or near its 1973 maximum extent, the lake is con- servatively estimated to have contained approximately 400x106 m3 of water. Most of this enormous resource is annually lost to evaporation. Diversion, storage, and utilization of this water is facilitated by the geographic location of the source and the settlement patterns around the playa. The lake’s three principal streams form a composite alluvial plain that borders the western margin of the playa (fig. 89). The city of Qom and its hinterland receive their water from the streams, wells, and qanats (underground channels used to convey water) on this huge alluvial plain. There is almost no settlement along the north- ern, eastern, or southern margins of the playa. Small earthen dams on the plain and larger dams upstream could store the water during the period of maximum discharge (fig. 90) in April and May and extend its use during the summer dry period. There would be lit- tle or no negative economic effect of the lowered water table east of the alluvial plain. In fact, the depressed water table of the playa would result in a firm hard crust throughout the year that would facilitate trans- portation and exploration for salts of economic value. The juxtaposition of the agricultural and oil resources of the Qom area, possible salts of economic value in the playa, and a significantly increased supply of water are natural possibilities for economic development that should be more thoroughly investigated and consid- ered. 139 TS—1, A New Window on Our Planet 00 - wwoz I I so I (‘1qu Contain ml low I .3002 I law | 450002 N B 3 4 B B I 00 I ALOQZ - - l 052-3OI '08l l3§El852-28 N m-MOSZ'ZS figz ? R SUI EL47 82138 IN-é‘H-fi-l-N-D-ZL MSFI ERTS E-IWI-Eggl Bl APPROXIMATE SCALE 10 20 30 MILES 10 0 10 20 30 KILOMETERS FIGURE 88,—Color composite ERTS—1 image of the Qom Playa area of west-central Iran, Sept. 22, 1972 (1061—06381). 3, Applications to Water Resources 141 {£85} '38 5852-883 51835-365 EBSZGW EBSB-QB: Db) ' (”(002 I IGQ I meZ I DO I —U'|Df"l I Q00 I thZ N 8 3 4 B B 5 7 R M flgfifi‘s IW-qlm-fi-l-N-D-‘IL mga'Eg‘E-IZSS-mlq 0| APPROXIMATE SCALE 10 20 30 MIL ES 10 l0 20 30 KILOMETERS FIGURE 89.—Color composite ERTS—1 image of the Qom Playa area of west-central Iran on May 14, 1973 (1295—06391). 142 ERTS—1, A New Window on Our Planet QOM (928 m) Mean monthly temperature and precipitation; mean annual temperature, total annual precipitation,and altitude of the station at Qom. 100 400 I) ' ated ”ke’vihfle” V U) Esiflg” a: r”’ L|J // E 2 I E LIJ I 2 g g m 75— I -300 o O. I LL E I o ' 2 < I 9 .J .J >- I 1’ m I 5 o 50' I —200 z E _ l I ui 2 I 3: 8 I .J O I L < 0 Is: I Lu < 25- I E g I Lake area as percent of playa area '100 (-3] < I > " I n_ O L|J I— < E '— 33 l l I I 0 SEPT OCT NOV DEC JAN FEB MAR APRIL MAY 1972 1973 Date of ERTS-l image FIGURE 90.—Comparison of the Climatic data from Qom with the lake area at Qom Playa, as a per- centage of the playa area, and the estimated lake volume from Sept. 4, 1972, to May 14, 1973. LAKE FLUCTUATIONS IN THE SHIRAZ AND NERIZ PLAYAS OF IRAN By Daniel B. Krinsley, US. Geological Survey hiraz Playa and Neriz Playa occupy separate but adjacent basins within S the Zagros Mountains watershed of southwest Iran. Pleistocene beaches that are similar in number and in relative vertical position and similar basin/playa ratios indicate that the two playas have had similar hydrologic responses to essentially the same climatic factors of precipitation, temperature, and evaporation. The intermittent lake at Shiraz Playa (to left of image), although quite shallow, fills the center of the valley bottom during the spring runofi' period. In April 1967, near its maximum seasonal extent, the greatest measured depth of the lake was 50 cm (Huber, 1967). Ground observations by Bobek (1963) at Neriz Playa in June 1963 and by Krinsley in October 1965 and August 1967 (Krinsley, 1970) and in September 1972 suggest that the maximum depth of the playa lake may have been 2 m within recent time. Three color composites of ERTS—l images of Shiraz and Neriz Playas (figs. 91, 92, 93) were prepared from the ERTS—l positives of seven images from Sept. 2, 1972, through Aug. 28, 1973. Data obtained by measuring the areas of the playas and of the lakes in each scene were used in the construc- tion of figure 94. Lake Shiraz covered 66 percent of the playa area on Sept. 20, 1972 (figs. 91, 94), and had an estimated average depth and volume of 0.1 m and 16X106 m3, respectively (fig. 95). The lake at Neriz encompassed 21 percent of the playa area and had an estimated average depth and volume of 0.4 m and 68><106 m3, respectively. Except for a deep pool near the west shore of Lake Shiraz, water depths were uniformly distributed. The deepest water in the lake at Neriz was in the western part of the playa (fig. 94) ; the long narrow central area of the lake had very shallow water. This period at the end of the long hot summer, during which rain is generally absent (fig. 95) and evapora- tion rates are highest, has the lowest ground-water levels and lake areas of the year. Lake Shiraz occupied 94 percent of its playa area on Mar. 1, 1973 (fig. 92, 94), and had an estimated average depth and volume of 0.4 m and 94X 106 m“, respectively (fig. 95). The lake at Neriz expanded to 99 percent of its playa area and had an estimated average depth and volume of 1.0 m and 794x106 m3, respectively. It seems reasonable to assume that some of the precipitation 143 IWIW 93:sz 144 ERTS—1, A New Window on Our Planet 553-00 ' 5053-3“ EOE-Ni EOE-NI APPROXIMATE SCALE 0 10 20 ”MILES | l l 1 1 l l i l 0 l l 10 20 30 KILOMEYERS FIGURE 91 .—Annotated color composite ERTS—1 image of the Shiraz and Neriz Playas of Iran on Sept. 20, 1972 (1059—06283). INIM 3, Applications to Water Resources 145 falling at the highest altitudes of the narrower Shiraz basin would remain as snow, while most of the precipitation falling in the lower, broader valley of the Neriz basin would be rain that quickly moved toward the playa. These considerations combined with the period of the annual precipitation maximum (fig. 95) and evaporation minimum could explain why the lake at Neriz ap— peared to reach its 1973 maximum extent ahead of Lake Shiraz (figs. 94, 95). Lake Shiraz had contracted to 1 percent of its playa area by Aug. 28, 1973 (figs. 93, 94) and had an estimated average depth and volume of 0.3 In and 0.9X106 ms, respectively (fig. 95). The lake at Neriz contracted to 5 percent of its playa area and had an estimated average depth and volume of 0.5 and 19><106 m3, respectively. The sequential images of these playas pro— vided by the repetitive coverage of ERTS—l make it possible to observe and measure efficiently and accurater the extreme variation of these lakes within a single year. Note that almost 1 full year after Sept. 2, 1972 (fig. 94), Lake Shiraz had almost disappeared and the lake at Neriz was reduced to one small lake and two separate ponds. This extreme variation is due primarily to the marginal climatic equilibrium of these lakes, the delicate balance between pre- cipitation and evaporation. The current lack of complete synchroneity between the lakes in the periods of minimum and maximum lake fluctuation is ac- centuated by man’s intervention in the hydrologic cycle of these lakes by his increased diversions of water through dams and pumped wells. From February through May 1973, there were at least 600x106 m3 of water available in the lake at Neriz (fig. 95) ; this figure obviously may vary annually with the climate and with the magnitude of the drainage diversions. This region is important agriculturally, and more recently it has become the site for industrial development, including a large oil refinery. Consequently there is need for the large amount of water that is lost to evaporation each year, evaporation that is facilitated in a large body of very shallow water. Larger, deeper reservoirs are required to store the water during the long dry summer. Consideration should also be given to the ecological and local eco- nomic effects of further water withdrawals from the lake. The larger villages along the southern shore of the lake have qanats (underground channels for transporting water) for fresh water but use pumped wells to augment irriga- tion. If the lake disappears, there will be local climatic effects of increased aridity and changes in the plant and animal communities. These hydrologic and biologic changes may be undesirable and irreversible and should be con— sidered before any additional water is removed. Although the salt crust at Neriz Playa is thin, there may be buried crusts that are thicker as well as brines that have salts of economic value. The gen- eral accessibility of the playa and its deposits argue for a systematic investi- gation of its resource potential. Lake Shiraz had a relatively negligible water supply from February through May 1973 (50X10‘ m3 of water). Some of this could no doubt be diverted for agricultural or industrial use, but the withdrawal would serious— ly affect the discharge from the several pumped wells in the vicinity. The amount of water is marginal and may not justify any significant expenditures of money for diversions and storage. Salt from the west shore area is cur— rently used for human consumption, and this use could be expanded. 146 ERTS—1, A New Window on Our Planet I00) I 1.01002 00) I AVID"! I I DO I (DNOZ law I mmz N B 2 8 3 B I DO I @1002 aImR'za c digging-2: N m-m-W' 7 R sun [-142 azfingeig'aavs-o-Efiifi men ears mat-@1518 APPROXIMATE SCALE 10 1) MILES lO 0 10 20 30 KILOMETERS FIGURE 92.—Color composite ERTS—1 image of the Shiraz and Neriz Playas of Iran on Mar. 1, 1973 (1221—06293). 3, Applications to Water Resources 147 I 0(a) ' (DNOZ I 00 I WNOZ I 00 I LONG: N B 2 8 3 B I 00 | ONO: 10 30 MILES 0 10 FIGURE 93.—Color composite ERTS—1 image of the Shiraz and Neriz Playas of Iran on Aug. 28, 1973 (1401—06280). h 148 ERTS—1, A New Window on Our Planet SHIRAZ PLAYA ” NERIZ PLAYA SEPTEMBER 2, I972 SEPTEMBER 20, I972 SALT AND CLAY FLAT "K SHORELINE PARTIALLY OBSCURED BY CLOUDS DECEMBER 19, I972 MARCH I, I973 MARCH 19, I973 MAY I2, I973 % ® ,1 0 10 20 30 MILES b L I l I % I I I I 0 10 20 30 KILOMETERS FIGURE 94,—Diagram showing lake fluctuations at Shiraz and Neriz Playas, 1972—73. 3, Applications to Water Resources 149 100 800 ll \ / '700 / \ // .o / \ / k .° / \ / \e / v Q — 75‘ ‘ or 600 g 99“ I \ m i °‘ 1 / Li .— \,o¥° ° sh” / \ 2 z o ‘8 / \ a a: D “- —500 u. E I \ o :2 / \ ‘2 < / \ ‘3 A _| a II E _ z .3. 50‘ '9 I _ 400 .- g 6‘ / .C Neriz 0,609 m) Mm I: o A? j 0 \° 30 I7 0 . -80 O Q / . .. u_ ‘ o < ‘0 l 3: a “‘ “ a“ r” 1 3 < Q #0 / ‘300 _1 > a O 5 0° / —10- > "L 0‘" / SONDJFMAMJJA S ~19 / Mean monthly temperature and precipitation; mean I; v0 0 annual temperature, total annual precipitation,and 2 as altitude of the station at Neriz. r. 3/ 8 25 — . \ —200 34 a/o“ \ K % 0 he/ \ «7/ \ - . -‘IOO \ / //' A\:hl°'°d / \/ // S\’\°/r. Vol // ""°z"\ime \ \\ ’/”/// Y” \\ 0 I l I l I I I N SEPT OCT ' Nov DEC JAN FEB MAR APRIL MAY JUNE JULY AUG 1972 1973 DATE OF ERTS-l IMAGE FIGURE 95.—A comparison of the climatic data from Neriz with the lake areas at Shiraz and Neriz Playas, 1972—73, as a percentage of the playa areas and the estimated lake volu me from Sept. 2, 1972, to Aug. 28, 1973. ECOLOGICAL MODEL IN FLORIDA By Aaron L. Higer, A. Eugene Coker, and Edwin H. Cordes, US. Geological Survey housands of years of seasonally fluctuating water supply, punctuated periodically by drought or un— seasonally heavy rain, have resulted in a natural balance of plant and animal communities in south Florida. W'ater fluctuations, together with fires and hurricanes, contributed to the shaping of the ecologi- cal communities, that is, the tree islands (composed of woody vegetation) and grassland communities (wet prairies and sawgrass marshes). This natural ecologi- cal balance, however, is now influenced by a modified water regime, altered by water control within the Kissimmee—Okeechobee—Everglades watershed for flood control, crop irrigation, and coastal urban use (fig. 96). The Central and Southern Florida Flood Control District manages this watershed that contains more than 22,500 km of canals and levees. An effect of water deficiencies in Everglades Na- tional Park is the failure of wood storks to form rook- eries. Wood storks nest in winter at the inner edge of the mangrove belt in the Everglades National Park in south Dade and north Monroe Counties. According to John Ogden, an ornithologist of the National Park Service (written commun., 1973), the wood storks were successful in forming rookeries in 1959, 1960, and 1961 but failed for 5 successive years (1962—66), when low rainfall in south Florida resulted in prolonged drought in the park. The success or failure of wood stork rookeries is a significant index of hydrologic conditions in the park. Wood stork studies in Everglades National Park by the National Park Service suggested a working hypoth— esis for establishing the water conditions of Shark River Slough, the largest freshwater course in the park, needed for successful formation of these rook- eries. An annual prediction of success or failure of the 150 rookeries at the inner edge of the mangrove belt could be made in November, which marks the beginning of the dry season and precedes the height of rookery for— mation by approximately 2 mo. The prediction can be based on recorded water-level measurements together with a synoptic view of the spatial distribution of sur— face water, both available from ERTS data, and on the density of small aquatic animals collected in quantita- tive traps. The ecological model is designed to relate the wild- life in the Shark River Slough to the availability of food and water (fig. 97) (Higer and others, 1973). In an on-going study with the National Park Service, more than 50,000 aquatic animals have been captured and tagged. The species numbers and hydrologic data are entered into a digital computer program that pro- vides statistical summaries of species distributions and water depths at point locations in the slough. Time- variant synoptic displays using ERTS imagery taken concurrently with stage and rainfall data presently being collected from DCS (figs. 98, 99) may provide the following information to develop an ecological model (Higer and others, 1974) : 1. Knowledge of the quantity of water stored in the slough. .1"? Knowledge of the spatial distribution of water in the slough as it relates to available food for the bird rookeries (fig. 100). . Quantitative hydrologic data that allow manage- ment to know where and when to increase water into the slough from the upstream water storage areas. Ability to predict the number of aquatic animals in the slough and the success or failure of the rookeries, based on conditions of the hydrologic regime. 05 r“ 3_ Applications to Water Resources 151 KisslMMEE j FIGURE 96,—Color composite ERTS—1 image mosaic of the State of Florida prepared by the General Electric Co., Beltsville, Md., in cooperation with the US. Geo— logical Survey, Water Resources Division, Miami, Fla., the Central and Southern Florida Flood Control Dis- trict, and NASA. lAKf t‘mfi-CHOBFF APPROXIMATE SCALE 0 50 100 MlLES 5., 50 0 50 100 KILOM ETERS h 152 ERTS—1, A New Window on Our Planet Sufficient water must be maintained in the Shark River Slough of the Everglades National Park to pre: serve the aquatic community and the several bird and mammal species that feed primarily on fish. Theo amount and time of water releases to the park are a re- source-management decision based on very limited in- formation on the water storage that may be available :88 yawn 73m FIGURE 97.—Wildlife ecological model of the Shark River Slough, Fla. , ,. ,, I ; ’1‘ 4 FIGURE 98.—Data collection platform in Park in south Florida used in the the Everglades National ecological model study. to the north of the park. Small-scale thematic maps of water levels provide an accurate evaluation of water distribution. A gradual reduction of water levels be- fore the birds start nesting would result in the con- centration of fish in the Shark River Slough that may ensure adequate food for successful hatches of several rare and endangered bird species. . SURFACE WATER STORAGE MODEL SHARK RIVER SLOOCII, EVERCLADES NATIONAL PARK WA T‘ER “km?” _g_ V WW LEVEL FROM AREA DATA COLLECTION "0M PLATFORMS IMAGERY VOLUME OF WATER FIGURE 99.—Surface-water storage model of the Shark River Slough, Fla. FIGURE 100.—Wood storks nesting in the Everglades National Park, south Florida. RTS imagery of the area near Duluth, Minn, E shows prominent turbidity plumes in the western arm of Lake Superior (Stortz and Sydor, 1974). The correlation of image intensity with field observa- tional data (fig. 101) can be used to produce a water— quality map showing the concentration of suspended solids on the lake (Bennett and Sydor, 1974; Scherz and others, 1974). This is done either by use of optical density slicing of 70-mm bulk transparencies (fig. 102) and identifying each image-density range with the corresponding range of suspended solids (fig. 103) or by using CCT’S in a like manner (fig. 104). Two major sources of turbidity exist in the area (fig. 105), the polluted effluent of the St. Louis and Nemadji Rivers and the erosion of red-clay deposits along the southern shore. The measurement of turbidities on the lake and the problem of effluent tracing have important practical applications in the selection of the locations for new water intakes, in the design of filtration plants for the existing water intakes, and in studies of en- vironmental impact on the lake due to extensive harbor dredging. The interpretation of ERTS data is based on the spectral reflectance variation of particulate matter with the various bodies of water. Notice for in- stance that the harbor area of the St. Louis River ap- pears deceptively clean on the band 5 image (fig. 106), largely because of the high light-absorbing charac- teristics of the St. Louis River water. This fact is help- ful in tracing the St. Louis effluent. The variation in the M88 signal is shown in figure 107 for bands 4, 5, and 6 for the harbor effluent, and the south shore plume indicates that the turbidity plumes on the lake could be traced to their source of origin using the ERTS COT data. TURBIDITY IN LAKE SUPERIOR By Michael Sydor, University of Minnesota SEPT. 30, 1973 ._. m I ) 10— TURBIDITY (FORMALIN TURBIDITY UNITS I o 0 I | I I I | I I | I I 5 10 15 BAND 5 DIGITAL OUTPUT FIGURE 101.—Correlation of intensity from band 5 of ERTS—1 image 1434—16244 with turbidity. FIGURE 102.—Density-sliced image using color to show turbidity. 153 154 ERTS—1, A New Window on Our Planet 92°00’ Suspended solids (mg/D—Lake T 12—14 DULUTH O 46°45' — SUPERIOR 2 MILES 2 KILOMETERS FIGURE 103.—Harbor and lake image-density levels identified by corresponding turbidity levels on ERTS— band 5, Sept. 30, 1973. 1 image 1434—16244, 92°00’ 91°45’ 47° 00’— *DULUTH {NTAKE LAKE 46° DE? f x 45' ankeg’ 1' i i ‘ a 13M #5 § 1;? e g“ $9 'é’§| a“. e § V O 2 4 MILES l—1—l—i—‘ O 2 4K|LOMETERS FIGURE 104.—Computer printout of image computer compatible tapes of ERTS— -density levels from FIGURE 105.—lndex map of the Lake Superior study 1 image, 1434—16244. area. 3OSEP73 C N46-02/M9I 25 M35 DIGITAL OUTPUT 20 -32 N MG-BO/MSI-Zq M83 5 D SUN EL37 HZISI iSZ-BBSI-N-i-N-D-ZL WISH BITS E-l434-16244-5 0| APPROXIMATE SCALE 0 5 10 15MILES . . i I l J 0 I 5 10 15 KILOMETERS __¢.__ Harbor effluent ___o——- South shore turbidity I 5 M88 BAND NUMBER FIGURE 106 (above).—Part of ERTS—1 image 1434—16244, band 5, showing the Lake Superior study area. FIGURE 107 (Ieft).—-Graph showing variation in M55 band signals. ERTS—1, A New Window on Our Planet iWGQ wee-ear “879-38HNB44’68 -ha ,7 , . ' ONTARIO NEW VORK m E- l‘?‘ IN“! OI ”Wm-I mus-as 14%pran as; 1’ 0 m9; may rsrsm-u-i- TX APPROXIMATE SCALE 10 20 30 MILES 10 0 20 30 KILOMETERS FIGURE 108.—Annotated color composite ERTS-1 image of the Lake Ontario-Niagara River area on Sept. 3, 1973 (1407—15343). 7—71 . DYNAMICS OF SUSPENDED-SEDIMENT PLUMES By Edward J. Pluhowski, US. Geological Survey ity features are frequently visible on ERTS imagery (Pluhowski, 1973). About 91 percent of the inflow to Lake Ontario enters the lake along its southern shoreline, 86 percent from the Niagara River , m ,. p . , alone. Thus the principal sediment and nutrient load lmn c "43-144.379-53 N MEI-[2437945 n56 5 enters Lake Ontario from the south (fig. 108). The movement and fate of suspended material en- On the south shore of Lake Ontario, large turbid- a D SLN E148 RZISS ISI-m-N-l-N-D-ZL tering the lake can be determined by scrutinizing the "‘99 ERTS E' '263"538"5 3' large turbldlty features generated at the mouths of the FIGURE 109.—P art of an ERTS—1 image showing sediment f0110W1ng watercourses: Welland Canal, Nlagal'a plumes in Lake Ontario on Apr. 12, 1973 (1263—15361, River, Genesee River, and Oswego River. Turbidity band 5). A, Niagara River; B, Niagara River plume; and plumes are also created by a favorable juxtaposition of C, We'land Canal P'Ume- wind, waves, and shoreline orientation in combination with high lake levels and exposed coastal headlands. Shoreline erosion generated by this unique combina- tion of factors will result in extensive nearshore tur- bidity plumes along coastal reaches of the lake. Examples of heavy beach erosion and highly turbid longshore currents are illustrated in the imagery shown in figures 109 and 110 obtained Apr. 12 and 29, 1973, respectively. Turbidity readings of 400 J TU and 420 J TU were obtained on Apr. 12, 1973, in the narrow band of milky white nearshore waters between the Welland Canal and Niagara River. These were by far the highest turbidity readings obtained in this study to date. Extensive beach erosion is shown in the H 5}; 3 imagery for April 12 and 29 in all shoreline areas ex- 2m. ”*‘ * ~ cept those immediately east of the Niagara River 73 c ma-ZI/w‘re-ze N M3"W7a"s "55 5 mouth. On both occasions an eastward-trending wave D 5““ 5L5“ "2'35 '9"39°3'N"'N’D‘2L train pounded the southern shore of the lake. How- Mesa ERTS E-izea-Isaoz-S 0| ever, the northwest orientation of the Niagara River APPROXIMATE SCALE jet in Lake Ontario acted as a barrier to the ambient 10 o 10 20 30 muss ) wave train, effectively shielding part of the New York I ' i1 I 'I '1' i l l l I . . . 10 0 10 20 30 KILOMETERS State shoreline from eros1ve wave action. Three diStiHCt turbidity zones were depicted Off the FIGURE 110—Part of an ERTS—1 ima e showing sediment New York‘State Shorehne on Apr: 29’ 1973 fig: 110)’ plumes-in Lake Ontario on Apr. 2g9, 1973 (1280—15302, These cons1sted of a narrow but highly turbid httoral band 5). A, Welland Canal; B, Niagara River plume; and zone, an intermediate zone of much lower turbidity, c, offshore zone of turbulent mixing. 157 fi 158 ERTS—1, A New Window on Our Planet and a relatively clear-water (dark) offshore zone. Of special interest is the zone of turbulent mixing between the intermediate and offshore clear-water zones as APPROXIMATE SCALE 0 5 10 MILES 5 l_L l I I l l I l 5 0 5 10 KILOMETERS FIGURE 111.——Part of an ERTS—1 image, made on Sept. 3, 1973, and enlarged and color enhanced by Stanford University's ESIAC, showing the Niagara River plume (1407—15343). shown by the band of wavelike turbidity features in figure 110. The dynamic mechanism triggering these “turbidity waves” is unknown, but the amplitude and trend of the waves suggest the existence of a large westward—moving offshore current rather than an ap- parent eastward-moving longshore current. Many factors affect the size and shape of large tur- bidity features such as the Niagara River or Genesee River plumes, the most important in large quiescent water bodies such as Lake Ontario being wind speed and direction, volume of runoff, and differences be- tween the levels of turbidity of the discharging water- course and the receiving water body. By way of illus- tration, on Apr. 29, 1973 (fig. 110), under the influence of brisk west—northwest winds, a strong eastward- moving longshore current was generated. The shearing effect of this current on the northward-moving Niagara River plume is shown in the image. The plume ex- tended only 3.2 km offshore, but it was identifiable for a distance of at least 13 km downwind along the New York shoreline. The total surface area of the plume on Apr. 29, 1973, was 34 kmz. Gentle offshore winds on Sept. 3, 1973, on the other hand, greatly expanded the size of the Niagara River plume. The southerly winds on that day reinforced the northward-flowing plume. The ofl’shore winds pushed the leading edge of the Niagara plume about 30 km into the lake. As shown in figure 111, a large clear- water (dark) plume developed and covered 514 km2 of lake surface. WATER-MANAGEMENT MODEL OF THE FLORIDA EVERGLADES By Aaron L. Higer, Edwin H. Cordes, and A. Eugene Coker, a population of 2.5 million, depends upon the re- tention of water in four major impoundment areas in the Everglades water basin (figs. 112, 113): (1) Lake Okeechobee, (2) Conservation Area No. 1, (3) Conservation Area No. 2, and (4) Conservation Area No. 3. Shark River Slough, an important source of water for the Everglades National Park, at the down- stream end of these interconnected water bodies, also depends upon overland flow from adjoining Conserva- tion Area No. 3. An accurate accounting of the amount of water in surface storage is difficult because land- surface profiles are not available. The shallow water depths of 0.3 to 1.0 m, the flat terrain, the abundant vegetation, and the vast area of 3,600 km2 of the Ever- glades preclude the feasibility of determining accurate volumes by conventional methods. In the conservation areas and the Shark River Slough, the water does not pond in the usual manner but slowly flows over the gently sloping land surface. The water supply for southeast Florida, which has Several water-budget studies for the conservation areas are underway by the U.S. Army Corps of Engi- neers and the Central and Southern Florida Flood Control District. Elements that need more accurate definition in the existing water—budget studies are rain— fall, evapotranspiration, seepage losses, and surface storage. The ERTS water—management model uses the DCS to provide quantitative in-situ data on the elevation of the water surface and MSS data to provide infor- mation on the areal extent of the water surface (Higer and others, 1973). Knowing the relation between the surface-water area and surface elevation for the range of water levels, the storage can then be calculated (figs. 114, 115). In addition, knowing the change in stor- age and the surface inflow and outflow (input and out- U.S. Geological Survey put) from the system, it is possible to calculate evapo- transpiration and seepage (Higer and others, 1974). At present the DCS data are transmitted from the Everglades stations to the satellite and relayed via two ground tracking stations to the Goddard Space Flight Center, Greenbelt, Md. The data are then transmitted by teletype to the Miami office of the U.S. Geological Survey. The perforated teletype tape is then processed daily through a minicomputer to convert the data to engineering units and place it into the format requested by the Corps of Engineers. The data are then trans- mitted to the Corps of Engineers, Jacksonville, Fla., by telecopier. The time required for the transmission of the data from the Everglades via the satellite, the NASA tracking stations, and the U.S. Geological Sur- vey to the Corps of Engineers is less than 2 h. The importance of the space-relayed data can be shown by a comparison of the accuracy and frequency of those data received through the Miami teletype with data from the existing remote radio-transmission sys- tems in southern Florida. The great line-of-sight dis- tances involved in the radio-transmission systems often provide “rare” and garbled data messages. The fre- quent meteorologic disturbances in southern Florida prevent the transmission of the accurate synoptic in- formation on rainfall and water stage that is essential for managing the water for optimum conservation. ERTS—l provides the U.S. Geological Survey with five transmissions per day of these parameters and warns when any DCP recorder becomes faulty, so that it can be repaired within 24 h. This enhances the opportunity for a constant flow of information and makes it pos- sible for the Corps of Engineers to make daily de- cisions to optimize its water-control policy to conserve a greater proportion of the seasonally deficient water resource. 159 245243*4 0| APPROXIMATE SCALE 10 20 30 M I L ES 10 o 10 20 30 KILOMETERS FIGURE 112.—Color composite ERTS—1 image of the Everglades National Park area of Florida (1242—15240 . APPROXIMATE SCALE 10 o 10 20 30 MILES I I l I l I J I I I ‘ ' l I l l 10 o 10 20 30 KILOMETERS FIGURE 113.-—Annotated ERTS-1 image showing water-manage- ment conservation areas in the Everglades National Park area of Florida (1242—15240, band 6). 161 3, Applications to Water Resources DETERMINATION OF SURFACE WATER STORAGE IN CONSERVATION AREA 1 AREA DEPTH VOLUME WATER WATER SURFACE DISTRIBUTION X DEPTH : WATER ERTS—1 IMAGERY ERTS—1 DCS STORAGE FIGURE 114.—Determination of surface-water storage in Conservation Area No. 1. Schematic diagram of the use of space-relayed data to calculate surface-water storage. ERTS data from three successive passes on Feb. 14, Mar. 4, and Mar. 22, 1973, of Conservation Area No. 1 are used to demonstrate the feasibility of determining surface—water storage. APPROXIMATE SCALE 5 O 5 10 MILES I I I | I I l J I l I l ' I I I 5 O 5 10 KILOMETERS FIGURE 115.—Electronically prOcessed part of ERTS—1 image 1242—15240 of Conservation Area No. 1. Each dot rep- resents 4 ha of surface water. SUSPENDED SEDIMENT IN GREAT SLAVE LAKE, NORTHWEST TERRITORIES, CANADA / By Donald R. Wiesnet, National Oceanic and Atmospheric Administration ritories, is relatively unspoiled and unpolluted, but naturally occurring silt and other suspended sediment do surge into the lake from the nearby rivers. The unfrozen season is short in this arctic area, and runoff occurs only in the summer months during the snowmelt season. In the ERTS—l image in figure 116, sediment-laden Slave River is shown discharging turbid water into Great Slave Lake. The delta at the mouth of the river is evident, as are the distributaries. The highest concentration of suspended sediment (lightest tone) is coming from the Old Steamboat Channel, the southernmost channel visible. Note the deep blue of the Gaudet Bay and other smaller bays northeast of the delta and compare it with the lake waters adjacent to the bays. Note also the small ox- bow lake east of the delta and the intermediate blue color at that point. Winds at 10 kn were prevalent over the lake as ERTS—l passed over. These winds distributed the sediment in a pattern extending northeast along the shoreline, thus reflecting a northeast longshore current. The sharp wester- ly prong of sediment just 01f the northernmost channel, Resdelta Channel, occurs at a point where a sandbar is charted. The effects of a moderate south— westerly Wind on the water clarity of the lake are clearly demonstrated by this image. The west half of the lake is extremely clear and free of turbid water. 6 reat Slave Lake, during the short summer season of the Northwest Ter~ 162 3_ Applications to Water Resources 163 “HIS-N HHS-Ml Isa ' l0“): IOOND-w-l loo-Mm Resdelto Channel H I t 2 3 0 Old Steamboat Channel 90 ' —moz I 3529 “4-” N ran-mnq-m APPROXIMATE SCALE 10 0 10 20 30 MILES W 10 0 10 20 30 KILOMETERS FIGURE 116.—Annotated color composite ERTS—1 image of the Great Slave Lake area of the Northwest Territories, Canada (1024— 18272). DISCOVERY AND SIGNIFICANCE OF THE BEECH GROVE LINEAMENT OF TENNESSEE By G. K. Moore and Este F. HoIIyday, US. Geological Survey vealed a major lineament that may have considerable geologic, hydro- logic, and economic importance. It was named for the community of Beech Grove (Hollyday and others, 1973), where the lineament crosses Inter- state Highway 24 (open arrow, fig. 117 ). It extends from Lincoln to Smith Counties, Tenn. (fig. 118), a distance of about 165 km. Along most of its length, the lineament is less than 2 km wide, but in a few localities, closely spaced, parallel lineations suggest a fracture zone about 6.5 km wide. Along the lineament, hills are steep and covered by forests. Most culture is in the relatively flat stream valleys. The contrast between agricultural land and forest land is fairly sharp on October ERTS imagery, and thus there is good contrast between the valleys and the uplands. Also, the angle of solar illumination is relatively low in October compared to the spring and summer months, so that topography is somewhat enhanced by shadowing on the image (fig. 117) . The terrain has more of a three-dimensional appearance (because of lower Sun angle) in the Dec. 28 image (fig. 119), but there is somewhat less con- trast between forest land and agricultural land because all deciduous vegeta— tion is dormant. The net efl’ect is that the Beech Grove lineament can also be seen easily on the December image. The Beech Grove lineament is formed mainly by the alignment of nine separate stream valleys. The combination of land-use differences and topo— graphic enhancement by shadowing allows the lineament to be seen easily, de- spite the fact that it is not continuous. The trace of the lineament is obscured by woods in the upland areas, but its linearity and continuity are well ex- pressed by the valleys. The Beech Grove lineament is not obvious on maps or on either low- or high-altitude aerial photographs. Furthermore, it was not recognized as hav- ing regional extent during detailed geologic mapping on the ground. The lineament can be seen and traced on Skylab photographs, but its continuity Examination of a color composite ERTS image of central Tennessee re- . \ and possible significance are not as obvious as on ERTS imagery; the synoptic View of ERTS imagery was necessary for detection of this lineament. Central Tennessee is underlain by nearly flat-lying, dense, interbedded limestones and impure limy sediments of Ordovician to Mississippian age. The Chattanooga Shale separates these systems and is an important marker bed. 164 IWIMZ Iw'WD: msauqul Imnmmz 3, Applications to Water Resources 165 “4887-06 HESS-36% #888228? MESS-39% U888-38l HBSG’BBl H0 7- 8 8 EL39 92MB lSB-l l98-N-1-N-D-il. NHSH ERTS Flees-5544*? El 9 I N N35-57/H086- I mom c mean/up 8-23 9 nss APPROXIMATE SCALE 10 o 10 20 so MILES #l I I l I l I l l I l I l l l 10 0 10 20 30 KILOMETERS [*1 FIGURE 117.——Annotated color composite ERTS—1 image of central Tennessee on Oct. 17, 1972, showing location of the Beech Grove lineament (1086—15544). The two black arrows indicate the lineament, and the arrow below center marks the community of Beech Grove where the lineament crosses Interstate Highway l—24. U)WLSI‘; I WWI I 80) I UJWN‘ law I 010392 h 166 ERTS—1, A New Window on Our Planet Along part of its length, the Beech Grove lineament may consist of a group of parallel normal faults. This is not conclusive, however, and outcrops to the north and south of Beech Grove show no evi dence of displacement. of closely spaced, parallel fractures. Small movements may have occurred along these fractures, buithey only broke or brecciated the nearby rocks with no significant displaceme t, and there is no evidence of movement since Paleo— zoic time. Four small zinc—bearing veins at the surface in Rutherford and Cannon Counties are located Within 6.4 km of each other, but all four veins are within 3.2 km of the axis of the lineament. All these broken and brecciated rocks (Jewell, 1947). In mineral of economic value is sphalerite. The new Elmwood mine of the New Jersey Zinc Co. in Smith County is 3.2 kmeast of the axis of the lineament and 48 km north of these four veins. The zinc ore at this location occurs in brecciated Knox Dolomite of Early , ROBERTSpN ‘ flax“ (C; “ ,_ , ! {a 1 I 1’ IE WllilAMSON / \ ’fi‘l \ / ‘ . , some . ~ -’ l \, \‘VJJ\ ' ‘ r’ u i )x l i ' SZ/ .2 ,5.’£ER$AICNIE‘§}\ ’ if“ ‘4'?“ “ ’ .,.#V Y , ’1 ‘ . /S ,’ Vast—(Rf; ‘ WW {I l . . if . , _ . If?“ 7‘ /\ . , IION ‘ 1J7 } : o' , » 7‘ N Z. * 1' . <89 ‘ W ‘l ' / ‘4 ‘ 3‘: 4,: ;, ~~ ‘ , v .xMARjNfiL . ’ ,"‘.J.l,1 \Aq! 7‘ \ l. ‘ ‘\, r-yv .. \ | ’ . x ‘ . . i .J 'm' r'rmemTA/I, = ' ' ~ ~ /\ t.» x . ..: >5};.VL,.£.._l"./._L.S.L$l..<_.._‘z£>.:\_. "T""""/‘ A__‘__13£._‘\._k..-.\£.\M‘Q-~Ci J A L A B A M A Base from U.S. Geological Survey map 0 I I L I 5'0 MILES l I I ’F—I I o 50 KILOMETERS FIGURE 118.—lndex map showing the location of the Beech Grove lineament. 3, Applications to Water Resources 167 I N23? ‘33 NSES=38| H635 ‘35! - use-isssa-a B2 ZBDEBTZ C m-Wm-Zifie‘mbIW-ie PISS 4 APPROXIMATE SCALE 10 20 30 MILES 10 30 KILOMETERS 10 0 10 20 image of central Tennessee on Dec. 28, 1972 (1158—15550). The Beech Grove lineament can FIGURIE 119.——Color composite ERTS—1 d is indicated by the arrows. also be seen easily on this image an 168 ERTS—1, A New Window on Our Planet R. H. Hershey, Tennessee State Geologist, has stated that the Elmwood mine of the New Jersey Zinc Co. is at the intersection of the Beech Grove lineament and one of three minor transverse lineaments; other minor linea- ments also have intersections in Cannon County and Moore County. The latter two sites were termed “under—explored for the potential they have” (N ash- ville Banner, 1973). The three minor lineaments were interpreted from the October ERTS image (fig. 119). Several companies have expressed an interest in these prospects; one company has begun active exploration (Robert Manning, oral commun., 1974), but results are not available. The hydrologic significance of the Beech Grove lineament is difficult to determine because streamfiows, well yields, and spring flows all have large variations in dense fractured limestone terranes. For example, most of the streams that follow the lineament have either uncommonly large or small flows of water at any particular time, but so do many other streams that are remote from the lineament. Also, the yields of wells within 3 km of the linea- ment range from less than 0.06 Us to more than 6.3 l/s; a similar range in well yield also may be found in almost all other areas of similar size in central Tennessee. Many caves, sinkholes, and springs occur near the lineament, but these features commonly are abundant in valleys at the base of steep slopes, the same topographic position as most of the lineament. In some cases, ground water may move along the lineament from one stream basin to another, beneath drainage divides. Movement is always from a small stream at a relatively high altitude to a larger stream at a lower al- titude. Streams that follow the lineament may lose water to the ground in up- stream reaches and gain water in downstream reaches. These streams would be expected to have either uncommonly large or small flows at any point, depend- ing on the relationship of stream—channel altitude to water-table altitude. WESTERN LAKE SUPERIOR ICE By Michael Sydor, University of Minnesota inter shipping on the Great Lakes is an ever-increasing possibility, W particularly with the advent of the supercarriers 0n the Great Lakes. Duluth-Superior is a major port. Because of economy of shipping by water, considerable expenditure has been incurred by the Federal Govern- ment and private interests in attempts to extend the shipping season into the winter months. Navigation on the open lake is not often a problem, though better ice forecasting is essential. The problem generally arises in the locks, the harbors, and from severe ice packing that blocks the entries to locks and harbors. More frequent coverage by ERTS-type spacecraft would greatly aid ice forecasting. The ERTS image for Apr. 4, 1973 (fig. 120), shows a typical icepack on the western arm of Lake Superior that completely blocks the entry to the Duluth—Superior harbor. Notice, however, that the harbor itself is en- tirely ice free. Forecasting ice growth and predicting ice packing are generally based on consideration of the heat budget for the ice sheet (Maykut and Untersteiner, 1971). This in turn requires measurements of light albedo for the entire ice cover. ERTS data allow accurate measurement of albedo and also allow de- lineation of the severely packed ice (fig. 121). Figure 122 shows the light albedo for a harbor (bay) station and a lake station used in ice growth studies. Figure 123 shows the ice growth in the harbor. Figure 124 shows an estimate of the fraction of the ice cover on the west- ern arm of Lake Superior displaying highly packed characteristics. The cor- responding values for the volume of the lake ice, estimated from heat—budget considerations and the ERTS data, allow a rough calculation of the average thickness of the icepack blocking the shipping lanes. The average icepack thickness at the opening of the shipping season was 60 cm, a mild year. The ice packing for the 1971—72 season was much more severe, and ice remained in the area until June 9, 1972 (Sydor, 1974). 169 170 ERTS—1, A New Window on Our Planet ”SQ-WI 5382-30! I ow I .4502 u o 9 I 3 E a APPROXIMATE SCALE 10 20 30 MILES 10 0 10 20 3O KILOMETERS FIGURE 120.——CoIor composite ERTS—1 image of western Lake Superior showing a typical ice pack (1255—16322). PERCENT 3, Applications to Water Resources 171 APPROXIMATE SCALE 5 o 5 10 MILES . I I l l I l l 5 o 5 10K|LOMETERS FIGURE 121.—Density-sliced ERTS—1 image of western Lake Superior derived from image 1255—16322. Color-density slicing helps differentiate areas of contrasting albedo of ice and identify areas of intense packing: rose, tightly packed; dark blue, packed; and light blue, least packed. 80 | I I | I I I I ALBEDO / X ___x_ LAKE 60 — ___O_ _ BAY X X 40 _ O 20 — — 0 I I I I I I I I I I I I 10 20 31 10 20 31 10 20 28 10 20 31 10 20 DEC JAN FEB MAR APR FIGURE 122.—Graph showing albedo at two stations, western Lake Superior. 172 ERTS—1, A New Window on Our Planet 20 I I 400 __X—— Total area of ice cover _D_ Total volume \ —.—O—-— 15 _ Volume of ice pack — 300 —A— Area of ice pack A g N a o O H H x 3‘ "‘ E g 10— — 200 3 Lu 5 E D: D < _l O > 5 _ 100 0 I | I I I | I 0 5 10 15 20 25 31 4 Mar Apr FlGURE 123 (below).—Graph showing growth of FIGURE 124.—Graph showing estimate of volume of ice cover ice in the Duluth—Superior harbor. that is highly packed, western Lake Superior. 70 500 | l I | I | I | I | I I I | I I I ,X—‘ /é o \\ 60 _ / ~x\ BAY ICE GROWTH _ 400 3 o \ o l/ \\ Measured values / >< / \ "'X“ 50 _ /XO 0“ Calculated values _ 300 A / \ t: / \ "°"" '0 // \\ Net heat budget N E x’ \ E 8 40 ~ / xo , — 200 2 ‘— / \ —. I I 0 \ ’ 8 ’— / \ / l o. I A' no LIJ I 0 \ v D X ./ \ >< / .l \ u 30 — , / \ —— 100 3 9 0/ ,1 \ u. II f \x I; I ./ “J IX ,-’ I 20 — O / /' — 0 / .x' l _/ I / I /-’ I, ’0'”- 1o _ L._-—--—'-"‘"' — —100 0 | I I I I I I I I I I | I I l I I 10 20 31 10 20 31 10 20 28 10 20 31 10 20 30 10 20 Dec Jan Feb Mar Apr May MEASURING SNOW-COVERED AREA TO PREDICT RESERVOIR INFLOW By Robert M. Krimmel and Mark F. Meier, U.S. Geological Survey bout two-thirds of the population of the State of Washington live in the A vicinity of Puget Sound. Approximately 80 percent of the electrical energy they consume is derived from hydroelectric power reservoirs that are fed by melting snow in the Cascade and Olympic Mountains. Regulation of this runoff is also vital for domestic water supply, dilution of wastes, and the maintenance of a healthy salmon and steelhead trout population. In order to produce the maximum amount of power and to satisfy all other demands ggn therrwater supply, it is important to be able to forecast the runoff, and this can be done by measuring the snow in temporary storage on the ground. A mosaic of two color composite ERTS—l images (fig. 125) shows this area from the Fraser River delta near Vancouver, British Columbia, south to the cities of Chehalis and Centralia, and from the east half of the Olympic Mountains on the left to the western part of the Cascades on the right. The cities of Everett, Seattle, and Tacoma are on the east side of Puget Sound, and Olympia is at the extreme south of this complex waterway. Major reser- voirs include Ross and Diablo Lakes (upper right), Shannon and Baker Lakes (upper center), Alder Lake (lower right), Mossyrock and Mayfield Lakes (extreme lower margin), and Lake Cushman (southeast of the Olympic Mountains). Mount Rainier is the prominent snow-covered peak in the south- east part of the image. Three spectral bands were combined to form this color composite image. Clean water appears black, silty water appears blue, snow appears white, and vegetation appears red. Although these images were taken on July 29, 1972, note the large amount of snow still remaining in the mountains. The area of snow cover in nine im- portant drainage basins in the Cascades (fig. 126) is being monitored from ERTS images using the Stanford Research Institute ESIAC, which uses an electronically digitized image, variable density masks, and a computer. The snow—covered areas in these basins at the time of this image are shown in the following tabulation: Snow cover, Basin and name Percent A. Thunder Creek ____________________________ 44 B. Cascade River _____________________________ 33 C. South Cascade Glacier _____________________ 85 D. Stehekin River ____________________________ 32 E. Suiattle River _____________________________ 20 F. Sauk River ___ 39 C. North Fork Skykomish River _________________ 10 H. South Fork Skykomish River ________________ 9.1 I. Snohomish River __________________________ 16 173 use mnoz luau-qua: moi—45s: 174 ERTS—1, A New Window on Our Planet ‘Ni22-w iLUZZ-n iHlZl-x iHIZX‘u x22“ x21“ ' \ N 2 ? 3 ~ 1 2 Mt Baker B 5 A E J V S 3 B N 2 § B B P oo o 198‘ —~—: you - qua: Mt Rainier A lulu-m Iul vi” iulz , Iul |~ 29JLL?2 i: Me-la/HIZI-Is M Mada/Mizl-Erss 7 D an ELsa an; ins-east -I>N~D*|L raga $15 E‘lm-IBBIBJ 9| in -96 IN Iain-m 9 l - (HI - JLL72 C M7-I9/HI22~23 N M7-Ia/u122~2i 7 1] 5m ELSd fiZI34 193$ ~I-N-u-IL msn an zzfieasriaalaq BI wants in o w 20 so KILOMKYERE FIGURE 125.—Color composite ERTS—1 image mosaic of the FIGURE 126.—lndex map of Cascade Mountains drainage basins. Puget Sound region of Washington (1006—18310 and 1006— 18313). PERCENT OF BASIN AREA SNOW COVERED 3, Applications to Water Resources 175 By carefully studying successive images and related measurements on the ground during the spring and summer seasons, hydrologists can deter- mine the rate of change of snow-covered area and the amount of water stored as snow. The percentage of the basin covered by snow as a function of time is illustrated for four basins in figure 127. The snow-covered area during the ablation season is directly related to the volume of water stored as snow, and thus to the runoff to be expected. This allows predictions to be made on the availability of water from snowmelt for the rest of the summer. These data can be used by water managers to optimize the operation of reservoirs to bal- ance hydroelectric-power production requirements and domestic and other water needs and to control floods. Areas where clearcutting forests is prac- ticed—most noticeable in this image around Mount Rainier and south of the Olympics as rectangular or polygonal patches in forest lands—can appreciab- ly alter the runoff from drainage basins and also affect the visibility of snow in the forested areas. Evidence of the Puget lobe of the Pleistocene ice sheet can be seen on this image. The margins of the ice sheet that covered the Puget lowlands were roughly the east side of the Olympic Mountains, the west side of the Cascades, and the southern margin was roughly along the arc of lakes between the Olympics and Cascades south of Puget Sound. 7O 60- 50- 4o- 30" 20- 10- JULY AUG 0 A (Thunder Creek) X B (Cascade River) . E (Suiattle River) A G (North Fork Skykomish River) 1972 I I I I I I I l SEPT OCT NOV DEC l JAN FEB MAR APR MAY JUNE JULY AUG SEPT l l 1973 FIGURE 127.——Graph showing percentage of drainage basin area covered by snow. MAPPING SNOW EXTENT IN THE SIERRA NEVADA OF CALIFORNIA By Donald R. Wiesnet and David F. McGinnis, National Oceanic and Atmospheric Administration he 80—m ground resolution of the MSS on board ERTS—l provides images T to measure snow extent on moderately sized (250 to 30,000 km?) water- sheds. Melting snowpacks in the Sierra Nevada supply much of central and southern California’s water for domestic and agricultural consumption. Monitoring the extent of the snowpack via ERTS—l is quick and less expensive than a simple altitude survey by a light plane. Figure 128, produced using a color additive viewer, is a composite of three ERTS—l band 4 images showing the retreat of the Sierra Nevada snowpack in three stages during the spring of 1973, on Apr. 21, 1973 (1272—18122), May 9, 1973 (1290—18121), and May 27, 1973 (1308—18120). The area shown in light green is the area of maximum extent from which the snow melted from Apr. 21 to May 9, 1973. The area shown in blue denotes the area from which snow melted during the period May 9 to May 27 (18 days). White depicts the snow cover on May 27. Some minor cloud cover appears as green in Nevada to the east of the Sierra Nevada. ERTS—l MSS data have been used to check snow maps prepared from the NCAA—2 satellite images, which have a lower (~900 m) resolution (Wiesnet and McGinnis, 1974). 176 3. Applications to Water Resources 177 LAKE TAHOE APPROXIMATE SCALE 10 20 3O 40 MlLES 10 C1 10 20 30 4O KILOMETERS FIGURE 128.—Annotated composite of parts of three different ERTS-1 images color enhanced to show retreat of snowpack at three stages, spring 1973 (1272—18122, 1290—18121, and 1308—18120; all band 4). Light green shows greatest extent on Apr. 21, 1973; blue shows stage on May 9, 1973; off white depicts snow cover on May 27, 1973. SURGING AND NONSURGING GLACIERS IN THE PAMIR MOUNTAINS, U.S.S.R. By Robert M. Krimmel, Austin Post, and Mark F. Meier, US. Geological Survey ciers in the Pamir Mountains in the U.S.S.R. Most mountain glaciers move a few centimeters or tens of centimeters per day and slowly adjust to changes in climate by gradual advances or retreats. Surging gla— ciers, on the other hand, periodically change from this slow regime to a very rapid flow, on the order of meters per hour, causing rapid advances of the terminus amounting to 1 km or more per month. Such rapid ad- vances may cause lakes to be formed as tributary valleys are dammed by the advancing ice. Later these ice-dammed lakes may suddenly release, causing a catastrophic flood. In this ERTS image (fig. 129), the famous Med- vezhii (Bear) Glacier is shown just completing a cat- astrophic surge that caused widespread destruction. The glacier began to surge in April 1973 and by early June had advanced nearly 3 km. This surge created a major threat when the advancing ice dammed the Abdukagor River, forming a lake that may have been larger than 20 million m3. On June 20, 1973, the lake broke through its ice dam and caused a flood in the populated Vanch River valley. Because a flood was expected to follow the damming of the river, dikes had been built, bridges had been dismantled, and other pre- cautions had been taken, and thus no lives were lost although highways and powerlines were damaged. The image shows the Pamir Mountains to be a vast region of deep arid valleys heading in large glaciers. As in such Western States as Washington, Montana, and Wyoming, summer ice melt from these glaciers supplies critically needed water to irrigate lands. Surges of the Medvezhii Glacier occur at intervals of 10 to 12 yr. The Medvezhii Glacier is normally con- Figure 129 shows both surging and nonsurging gla- 178 fined to the tributary valley of Khirsdara and advances out to the Abdukagor Valley only during surges. This glacier has been studied intensively by glaciologist Dr. Leonid D. Dolgushin and his colleagues (Dolgushin and Osipova, 1972) of the Institute of Geography, Academy of Sciences of the U.S.S.R. Glaciologists of the US. Geological Survey in Ta— coma, “Tasha have identified six other surging glaciers, including Fortambek and Garmo, on this ERTS image. These glaciers have the periodically looped medial moraines that are unmistakable signs of past surges. One, the Bivachnii Glacier, appears to be primed for a surge of about 2 km in the next year or so. Surging features can be seen on 16 other glaciers. Also of interest in this image is the 77—km-long F edchenko Glacier, the longest in the U.S.S.R. and one of the world’s most studied glaciers. Its parallel medial moraines indicate that it does not surge. Some non— surge-relatcd ice-dammed lakes are visible at the mar- gins of the Fedchenko Glacier and are also a potential source of floods. As surges and related floods occur abruptly with little or no prior warning, glaciologists in countries that have surging glaciers, such as Iceland, Canada, Argentina, Chile, U.S.S.R., and the United States, are pooling information collected from intensive studies in order to locate and map hazardous situations, to pro- vide prior warning systems when surges and surge- related floods are expected, and, hopefully, to deter- mine the causes of these remarkable movements. Be- cause surging glaciers usually occur in relatively in- accessible terrain, satellites such as ERTS—l will be used more and more for the required monitoring. IOU) I (DI-0&2 I00 I ‘48!“ ISO I (06002 I on: I @0002 3, Applications to Water Resources 179 IEO?! ~38 lam-om 5072-38! Em-NI ' BiVACHNIIj‘GAr/I cm? "M. w I; ‘- ‘ MEDVEZHII GLACIER I/DIUKAGOR GLACIER ‘ I a‘u-w EB7I-3GI -MI - I - I I2JLL%3 C nae-swamps N N38- £67244 H65 45 R 51.14% flZI IS Iw-‘ISZS-G-I-N-D-lEfiflangS Elm-5 GI APPROXIMATE SCALE 10 10 20 30 MILES L 1 I 0 I I I I I | I I I I I I I I I 10 0 IO 20 3O KILOMETERS FIGURE 129.—Annotated color composite ERTS—1 image of the Pamir Mountains of the U.S.S.R. (1354—05224). I80 I LOWS: I DO) I (0tz MEASURING THE MOTION OF THE LOWELL AND TWEEDSMUIR SURGING GLACIERS OF BRITISH COLUMBIA, CANADA By Austin Post, Mark F. Meier, and Lawrence R. Mayo, US. Geological Survey Columbia, Canada, is shown in an image taken on Sept. 13, 1973 (figs. 130, 131). At that time it was undergoing a spectacular surge (rapid advance). The glacier, situated astride the British Columbia-Yukon Territory boundary 256 km northwest of Juneau, Alaska, flows out of the St. Elias Mountains into the Alsek River valley where it spreads out in a large terminal lobe 13 km across. The lobe blocks the main, river valley and forces the stream into a narrow gorge along the glacier’s margin. Because this gorge is impas- sable to boats and is the greatest hazard on the river, it has been appropriately named Turnback Canyon. Surges of Tweedsmuir Glacier in the past have dammed up the Alsek River at Turnback Canyon and formed lakes as much as 20 km long. The 197 3 surge may again close off the river, and if this should occur, sudden, perhaps repeated, releases of water from the lake when the ice dam fails could cause hazardous flooding in downstream channels and in Dry Bay, Alaska. Thus, it is important to monitor the behavior of the glacier and to measure the changing rate of ice flow in order to predict the growth of a potential glacier- dammed lake. ‘I' weedsmuir Glacier, 70 km in length and the largest glacier in British Figure 132 shows changes observed or inferred on Tweedsmuir Glacier near its terminus. The ice velocity was inferred from ERTS images by meas- uring the changing positions of moraine loops during the intervals between Apr. 15, July 22, Sept. 13, and Nov. 7, 1973, and drawing a smooth curve through the average displacement rates. The actual advance of the terminus was measured on the ground by Dr. Gerald Holdsworth (1974) of the Ca- nadian Department of Environment. These curves provide the data for predic- tion of the timing and the amount of advance of Tweedsmuir Glacier over the channel of the Alsek River. The study of a sequence of ERTS images of the surging Tweedsmuir Glacier has revealed other interesting features. Most important of these is the existence of a “shock wave,” that is, a steplike feature on the glacier that also marks the down-glacier limit of intense crevassing. (Although actual crevasses are rarely seen on ERTS images, regions of. intense crevassing appear dis- tinctly darker because of the shadows within the crevasses.) This shock wave 180 low-m2 Imlm—‘Z 00-sz 3. Applications to Water Resources 181 muse-ea Hl37-ml mas-m APPROXIMATE SCALE 10 0 10 20 3'0 MILES l l l l l I l l I ' l ' ' l l | l 10 0 10 20 30 KILOMETERS FIGURE 130.—Color composite ERTS-1 image of the Lowell Glacier and Tweedsmuir Glacier areas of British Columbia, Canada (1417—19531). IWIWZ 182 ERTS—1, A New Window on Our Planet FIGURE 131.—Annotated ERTS-1 image of the Lowell and Tweedsmuir Glaciers of British Columbia, Canada (part of 1417—19531, band 4). 3, Applications to Water Resources 183 Tweedsmuir Glacier 90 — —————— 'l 80 — t-——Average velocity of shockwave along 70 _ centerline Z O E 60— /Average velocity of 0- shockwave along (I) northeast ice stream E 50— l— Lu 2 z 40— >5 '— 5 30— C d Ice velocity 7 km above > /terminus inferred from 20* ERTS images Terminus advance, measured 10 — {ind 0 JlF'M‘A'M'JlJ'A'S‘O'N'D‘ 1973 FIGURE 132.—Graph showing the velocity of movement of the Tweedsmuir Glacier in 1973. advanced in midglacier about 8.8 km from Apr. 15 to July 22, an average rate of 88 m/ day, at least an order of magnitude faster than the actual velocity of the ice. Other features that could be seen on the ERTS images include the increasing relief along the valley walls, the spreading of zones of intense crevassing, and the deformation of medial moraines. ERTS images are thus shown to be useful records of important data for inaccessible, rarely visited areas such as the Tweedsmuir Glacier area. Further- more, using ERTS images to produce maps and quantitative displacement data for large surging glaciers is far more quick and efficient than using conven- tional aerial photography or ground surveys. For instance, the Lowell Glacier, which has dammed the Alsek River in the past, surged in 1968-70. A map of the medial moraine pattern had been made before the surge, using the labori- ous procedure of mosaicing and rectifying many aerial photographs. A new map' was made from this ERTS image, compared with the old map, and displacement vectors measured in just 1.5 h (fig. 133). This demonstrates the usefulness of ERTS imagery for the rapid mapping of large features. 184 ERTS—1, A New Window on Our Planet LOWELL GLACIER Aerial photography late summer 1954 M V \A ERTS 13 Sept. 1973 (1417—19531) O 5 10 15 MILES I Ir J I l l l l I—r I I I I l O 5 10 15 KlLOMETERS FIGURE 133.-—Maps showing displacement vectors and changes in medial moraines of the Lowell Glacier, 1954—73, from late summer 1954 aerial photography and a late summer 1973 ERTS—1 image (1417—19531). MONITORING THE MOTION OF SURGING GLACIERS IN THE MOUNT McKlNLEY MASSIF, ALASKA By Mark F. Meier, US. Geological Survey as much as 64 km in length situated around Mount McKinley in Alaska. Nonsurging glaciers, such as the Ruth and Kahiltna, flow at quite uni- form rates of only a few centimeters or tens of centimeters per day, and the medialiinoraines—dark-colored strips of rock fragments stripped from moun— tains situated between tributary glaciers—are quite straight and uniform. On the other hand, such surging glaciers as the Tokositna, Lacuna, and Yentna have Wiggly folded moraines that result from alternating periods of near stag- nation (lasting up to 50 yr) and of extremely high flow rates (lasting 1 to 3 yr when the ice may flow faster than 1.3 m/ h). The Tokositna Glacier (fig. 135) has just completed a surge that began in 1970. The Lacuna Glacier has been in a stagnant condition for 40 or more yr, and its dirty mottled surface shows the effects of severe melting. The Yentna Glacier was first observed surging in 1972. This image shows its folded mor- aines displaced more than 1,800 m down valley from their positions shown on recent maps and 1970 aerial photographs. Also visible on the ERTS image is a dark line where the rapidly flowing Yentna Glacier has sheared across the stagnant ice of the Lacuna Glacier (fig. 135). Why a glacier surges and why some glaciers surge but others do not, are questions of great scientific interest because this type of periodic sudden movement is common in many other phenomena in nature, perhaps even in the mechanism of earthquakes. Surging glaciers can advance over large areas and cause devastating floods by blocking and suddenly releasing large quantities of' melt water; thus there is much practical interest in monitoring their be- havior. US. Geological Survey scientists now are using ERTS images to keep track of many large surging glaciers in inaccessible areas. A better understanding of glacier hydrology is becoming increasingly important because of the potential of glaciers as sources of water supply. Gla- ciers are one of the few sources of water supply that remain unexploited, and, with the advance of civilization into the subpolar regions, more attention should be paid to these ice masses in relation to potential water-resources development. An enormous reserve of water, about three-fourths of all the freshwater in the world, or equivalent to about 60 yr of precipitation over the entire globe, is locked in glacier ice. T he ERTS image in figure 134 shows both surging and nonsurging glaciers 185 Oh) I DUI—E I DO) I (00,02 I I DO I 00,82 00 I DUI—E I low I NUDOZ 186 ERTS—1, A New Window on Our Planet ”1154-50 W-Wl INI53-M N 52-Nl 2911372 C BBZ-‘lm-M N BBZ-‘ll 175l-527‘fl88 5 D ELx FIZISS 199-9462- -l-N-D-2L M158 ERTS Elm-21020 Bl APPROXIMATE SCALE 0 1o 20 30 MILES 1 l l | l l l 0 1o 20 30 KlLOMETERS FIGURE 134.—Color composite ERTS—1 image of the Mount McKinley area of Alaska (1033—21020). IOUIOUI-‘I: 00"sz COIN—El 00'sz mlmzl 3, Applications to Water Resources 187 * a; , , W" RUTH GLACIER a w ’ KAHILT A {GLACIER APPROXIMATE SCALE 0 10 MVLES J Il‘lllll' Ill llllll‘ I 10 > O ' 10 KILOMETERS FIGURE 135.~—Annotated enlargement of the ERTS—1 image of the Mount McKinley area of Alaska (part of 1033—2i020, band 6). VATNAJCKULL ICECAP, ICELAND By Richard S. Williams, Jr., US. Geological Survey here are three characteristics of ERTS MSS imagery that make it unique T for mapping of environmental phenomena: (1) it can be related to the figure of the Earth; (2) it records spectral reflectivity in four broad bands of the Visible and near-infrared parts of the electromagnetic spectrum on videotape rather than photographic film; and (3) most importantly, it provides systematic, routine, and repetitive coverage of an area (Williams and others, 1974). Except for areas of high population density, the availability of recent aerial photography is rather uncommon, and no aerial photography exists at all of large remote areas of the world. ERTS imagery provides a heretofore unavailable time-lapse view of many types of dynamic environ— mental phenomena, including seasonal variations in snow cover, vegetation, and glaciers (Williams,.1972). Glaciers are extremely dynamic phenomena, subject to great seasonal variation, and are particularly suited for study and monitoring on ERTS imagery (Williams and others, 1975) for several reasons. Glaciers offer good contrast With surrounding terrain. Lateral, medial, and terminal moraines are usually large enough to be resolved at the 80-m maximum of ERTS sensors. The same is true of glacier-margin lakes, braided stream patterns on outwash ' plains, and sediment plumes of glacial rock flour in lake or marine waters. Furthermore, in images made under low—Sun-angle conditions, surface irregu- larities on glaciers are particularly pronounced because of enhancement of shadows on the white background. ERTS imagery offers two unique possibilities for glaciological studies not readily available by other methods. The first is the fact that regional synoptic studies of glaciers and icecaps can be made, and an entire glacier can now be studied as a total system rather than as disparate and often temporally sep— arated elements. The second unique aspect of ERTS, because of its 18-day cycle, is that—in addition to monitoring changes in runofl’, variations in the size and location of glacier-margin lakes, and variations in the position of glacier margins—the repetitive coverage permits monitoring of surging gla— ciers on a year-round basis. Figures 136, 137, and 138 are ERTS images of Vatnajiikull Glacier, the largest icecap in Iceland, taken in January 1973, July 1973, and September 1973, providing a time—lapse view. Figure 139 is a sketch map of the approxi- mate area shown by these images (Thorarinsson and others, 1974). The dynamic volcanic and glaciologic environment of Vatnajokull is strikingly shown in these images. 7 Figure 136 is a midwinter low-Sun-angle (7 9) band 5 image of the snow— covered Vatnajokull area of Iceland that shows: 1, the elliptical shape of a 188 3, Applications to Water Resources 189 APPROXIMATE SCALE 10 20 KILOMETER’S FIGURE 136.—Annotated enlargement of ERTS—1 image of the Vatnajé‘) kull area of Iceland in the winter (part of 1192—12084, band 7). 190 ERTS—1, A New Window on Our Planet hitherto unknown subglacial caldera and 2, the elliptical shape of a partially subglacial caldera. Although dark, two subglacial craters can be seen on the western edge of this caldera; a partially subglacial geothermal area extends southwest into the icecap through the westernmost crater. Other features include: 3 and 4, elliptically shaped central volcanoes; 5, faint elliptical features and associated nunataks which may represent a partially ice—covered large central volcano; 6, a well-known subglacial caldera, source of many catastrophic jokulhlaups (glacial floods), including one in March 197 2; 7, a frozen lake, another source of jokulhlaups, including one that occurred in August 1973; and 8, the partially snow-covered snout of a glacier. Around the periphery of the caldera 6 are a number of punctate features resulting from collapse after the March 1972 jokulhlaup. Several more collapse features, resulting from the August 1972 jokulhlaup, can be seen in a line between 4 and 6. Southwest of Vatnajokull are superb examples of northeast-trending gra- bens, crater rows, and hyaloclastite ridges. Two prominent volcano-tectonic lineaments can be seen on this image. One extends N. 45° E. for 80 km from between 1 and 2 to the southwestern edge of Vatnajokull. The second linea— ment extends N.35°W., just north of 7. Concentric recessional moraines in front of an outlet glacier can be seen at 9. Media] moraines are visible at 10 (Williams and Thorarinsson, 1974; \Villiams and others, 197 30). Figure 137 is a midsummer color composite ERTS—l image. The high Sun angle (42°) and high reflectivity of the snow-covered glacier limit the amount of surface detail as compared with the low Sun angle of the winter- time image (fig. 136). The icecap, however, exhibits a completely different character because summer is a time of dynamic activity around and on the glacier. Ablation is at a high rate, and runoff is at its maximum across outwash plains. Changes in glacier—margin lakes and glacier termini can be monitored systematically on ERTS images. Types and distribution of vegetation around the icecap can also be delineated (Williams and others, 1973b). Older snow- pack can be seen at 1 where it has drifted. Sediment plumes can be distin- guished at 2 and all along the coast. Several glacier—margin lakes are visible; note the maximum area encompassed by 3, before the August 1973 jokulhlaup. Several braided glacial rivers cross this outwash plain. Undistorted moraines can be seen at 4 and contorted moraines at 5. The retreat of the snowline can be seen on most of the glaciers, including 6 and 7 (Williams and others, 1974a). Figure 138 is an early fall color composite ERTS—l image. As the Sun angle drops (25°), surface detail again begins to appear, although it is not as pronounced as on the wintertime image (fig. 136). Note the reduction in sedi— ment plumes along the coast and the decreased discharge of glacial rivers across the outwash plain. Note the retreat of the snowline as compared with figure 137. Note also the reduction in the lake area at 1 after the August 1973 jokulhlaup, as compared with figure 137 (Williams and others, 1974a) . Eyjabakkajokull began to surge in late August 1972. By the time of ac- quisition of the first ERTS image on Oct. 14, 1972 (Williams and others, 1973a), the glacier had apparently already moved slightly more than 1 km. The glacier was imaged again on Sept. 22, 1973 (fig. 138). According to measurements made on the two ERTS images, Eyjabakkajokull has surged an additional distance of 1.8 km. Measurements made on contorted medial mor— aines and volcanic ash layers at 5 on figure 137 between the two dates, Oct. 14, 1972, and Sept. 22, 1973, give an estimated 600 m of glacier motion in that part of Skeidararjokull in a period of 11 mo. N8 V 01036322! I USN/n) # LDMNL non-92 I on»: i630 ' DOVLJZ 00 I 0M8: I 3, Applications to Water Resources 191 i i?- i 288—5184-H-i-N-D-2L men ERTsug-i 9342M»? 82 wens-am Lima-Be " 7 Qa/NBW-ZS ”SS R SUN EL42‘FIZ! APPROXIMATE SCALE 0 10 20 30 MILES i i l | } I | O 10 20 3O KILOMETERS FIGURE 137.—Annotated color composite ERTS—1 image of the Vatnajokull area of Iceland in the summer (1372—12080). ‘ ‘Ji ‘ an. i am '96) . £30784 i [0)!» « (Jamey; {33(5) 0 (Jr—«NIL. [MUM—GI: low-hm: ”*m—Dtl IOOVU‘IIDOZ tau-am 192 ERTS—1, A New Window on Our Planet ”BIB-00 WIT'MI IWS’M ”BIB-m 228EP73 C qu-lZyfléfiggé N NB‘l-B 930-?9118 H85 4 gage-8&5 flZIB‘l 208-5937-R-l-N-D-2LullalFllgéaEFsTS E-l‘lZB-IZBTB—‘l 0] w APPROXIMATE SCALE 10 20 30 MILES I 1 4l | 10 20 30 KILOMETERS FIGURE 138.—-Annotated color composite ERTS—‘l image of the Vatnajékull area of Iceland in the fall (1426-12070). WIUI‘DZI ens-Jam: I OOIUl—QE I OUIAUJDZ I ouval 193 3, Applications to Water Resources \ {)0} ,2 [I’Hlnuuésma 65°00 \\\\\\m 1,} TUNGNA FELLsx¢° E .y .. § 5 \\\\\\\ll|I//// o, JOKULLg 5 8° E KVERKiJ LL :‘m,,.m\°° : .Bér‘darbunga . ’z \ .' ”u \N‘“ .‘ - - " VA TNAJOKULL " EsuuFaéLJ. .‘ § Grimsv'dtng? [(3 § l-Iiamarinn \— :“‘1\«\7/W“ ‘ Ii \\\ In” Héabunga. A TLANTIC / Kerlingar \,\« BEE/DAME}? . K . (A) UPJOKUL OCEAN (Wed 20 MILES 20 KILOMETERS EX P LA N ATl O N I: Late Quaternary and recent volcanism ‘ Early Quaternary flood basalts ‘\\\\\\\\\l”l”ll "’11,, “m“ 1,, . ‘\ ’2 N m Tertiary flood basalts .oo' / TORI-:AJOKULL - 6" I,” :5 Alluvial plains /, : ”IvIuImm...,,,,,”“m\¢“ -,‘,‘\':- —}.’- Crater row I I I I I n Topographic expression ' H m Caldera M YRDA LS‘JOKULL — " Contact— Dotted where concealed \ FIGURE 139.—Sketch map of the Vatnajékull area of iceland. GLACIOLOGY IN ANTARCTICA By William R. MacDonald, US. Geological Survey omparison of an ERTS image dated Dec. 24, 1972, C with the published US. Geological Survey 1:250,000-scale map of Ross Island disclosed a unique change in the Erebus Glacier Tongue (fig. 140). Further examination of photographs and historical maps indicated that the present position of the tongue is about the same as it was in 1910 and that the tongue had advanced about 9.6 km since 1947 and 4.8 km since 1962. A lateral shift or curving of the leading front toward the mainland seems also to have occurred since 1970. Sources are not adequate to determine whether the movement occurred gradually or rapidly. Some evidence does seem to indicate that the tongue may have gone through a surging period. Perhaps it has completed a growth cycle and will again break off as it did in 1911. If field investigations prove it to be a surging glacier, it will be the first one found in Ant- arctica and, therefore, of great interest to glaciologists. Further indication that ERTS imagery is useful for detecting glaciological changes is given by figures 141 and 142. An ERTS image dated Feb. 20, 1973 (fig. 141), was compared with the published US. Geological Survey 1:500,000-scale sketch map of Ellsworth Land and Palmer Land and with aerial photographs and shows that the Ronne Ice Shelf has advanced about 16 km since January 1966. Another excellent example of detecting glaciologi- cal changes on images is documented in figure 142, a planimetric sketch map compiled from ERTS images taken Jan. 21, 1974. When compared with the most recent and largest scale map available of the area, a 1:250,000—scale Japanese series chart, and other charts at scales 1:1,000,000 to 1:3,000,000 compiled by Japan, the U.S.S.R., and Norway, it is readily apparent that the Shirase Glacier (A) and Fletta Bay Glacier (B) tongues have advanced approximately 52 km and 69 km beyond the positions depicted on the maps. An im- portant and unanswered question is whether the 194 APPROXIMATE SCALE 5 o 5 10 MILES | I I l I I A I I I I I I I I 5 o 5 10 KILOMETERS FIGURE 140.—Annotated enlargement of ERTS—1 image of the Erebus Ice Tongue of Antarctica (part of 1154—19322, band 7). Analysis of ERTS—1 images and library sources showed that the Erebus Glacier Tongue has advanced 9.6 km since 1947. Place where the tongue broke off in 1911 is indicated. APPROXIMATE SCALE 10 O 10 20 3O 4O 50 MILES 10 O 10 20 3O 4O 50 KILOMETERS FIGURE 141.—Annotated ERTS—1 image of the Ronne Ice Shelf of Antarctica (part of 1212— 11133, band 7). The edge of the shelf has advanced about 16 km since 1966. changes have been caused by a recent glacier advance or instead reflect inadequate mapping because of limited source materials. Of special interest is the discovery from ERTS im- ages of new geographic features on the polar plateau northwest and southwest of Ross Island. Repetitive coverage obtained in January 1974 shows the new fea— tures in even greater detail. Car'tographers expert in interpreting ice and glaciological features on photo- graphs suggest that some of the new features have I 195 3, Applications to Water Resources considerable height relative to the surrounding ice- and-snow terrain and that a gradient is evident, the blue ice being on the leeward side. Other characteristics indicate extensive crevassing. Detailed analysis of the newly discovered features is planned by the National Science Foundation and will start as soon as conven- tional low-altitude photographs are obtained. Bad weather and logistical problems prevented aerial pho- tography during the austral summer of 1973—74. L I'J'Tzo W-HOLM BA Y .- ' ' " . I ' f . 9Q” ONGUL ISLAND a ‘ SYOWA STATION (JAPAN) , J— ' ' 7/? J p ’ ‘a/ . ’/ ~ 40°E ’Sr ' L /'/,/ f ’ 40°E 4,94 \f— // \_ 7 / // F‘ o 7 \ \ 7015 S <0 ‘\\ i?— /,_.’ \f d/// 6804518 fi_- I ’ v 0 10 20 3O 40 MILES .1 L....I I I I I I 40 KlLOMETERS / FIGURE 142.—Sketch map of the Liitzow-Holm Bay area of Antarctica compiled from ERTS imagery. MONITORING FLOOD INUNDATION By Roger B. Morrison and P. Gary White, US. Geological Survey RTS infrared images from bands 6 and 7 have proven remarkably help- E ful for appraising and mapping rapidly the areal extent of flood inunda- tion. The inundated areas are very sharply defined in images taken dur- ing a flood, if the water is not very muddy, and can be mapped accurately in detail because of the high contrast of the water (black) and nonflooded areas (light tones). Indeed, using computers for automatic mapping from MSS, the damage to large areas can be assessed in a fraction of the time previously required. Figures 143, 144, and 145 eloquently document the severity of the spring 1973 floods in the Missouri-Mississippi River valleys. These, the worst Mid- west floods in history, lasted 2 m0, drove 35,000 persons from their homes, and inundated more than 5.3 million ha. All these images are band 7. The three figures show the same area of southern Illinois, southeast Mis- souri, and western Kentucky at the confluence of the Mississippi and Ohio Rivers. Preflood conditions on Nov. 24, 1972, are shown by figure 143. The Mississippi, Ohio, Cumberland, and Tennessee Rivers are at within—bank dis- charge stages. Here the flood plains are not easily distinguished because they are largely dry, but rivers and lakes are clearly evident. Figure 144 shows conditions when the main rivers were in various stages of flood on May 5, 1973. Their flood plains are largely covered by flowing or standing water (black) and wet soils (dark tones). Light-toned areas within the flood plains are well-drained soils above the flood limit, mainly point-bar deposits. The widest and most extensively inundated flood plains are in the older, broader, ancient-valley reaches of the Mississippi (1 and 2) and Ohio (3) Rivers. Narrow flood plains and higher flood crests are in the confined reaches (4 and 5) where the rivers have had time only to incise narrow val- leys. Also of interest are the effects of various artificial and natural levees. At 6 the floodwaters of the Mississippi are being dammed north of the dikes of the Headwater Diversion Channel at Cape Girardeau, Mo., creating a large slack-water area. At 7 the levees skirting the main channels control normal floods, but during large floods they keep the overbank waters from returning to the main channel and also hold back water from tributary streams; thus they deter postflood drying of the flood plain. Figure 145 records a period of retreat of the floodwaters on June 10, 1973. The flood plain of the Ohio River is approaching normal, Whereas that of the Mississippi, which drains a much larger area, is slower to dry. On the Mississippi’s flood plain, much standing water remains, and the poorly drained 196 I 80 I 0002 I ah) I «11.002 00 I GOD: I I 00 I '0tz 3, Applications to Water Resources 197 ”4089-30 ”BBS-OW H088-30I ”BBB-BGI 14689- 36 I H088 -80| - - 24NOV72 C N37- 24/“688 - 50 N N37 '21 41088 - 48 I185 7 D SUN EL27 92154 19] - 1728 - N - III-6390 glad NHSIHuaEeRaTsaaE - l 124 - I 806 l - 7 GI APPROXIMATE SCALE 10 20 3'0 MILES 0 | 1 1 1 I I I l I II 0 10 20 30 KILOMETERS FiGURE 143.———Annotated ERTS—1 image showing the confluence of the Mississippi and Ohio Rivers in preflood condition on Nov. 24, 1972 (1124—16061, band 7). I ow I «10082 I50 I «“082 198 ERTS—1, A New Window on Our Planet fine alluvium of former channels still is moist although the better drained sediments, especially point-bar deposits, have dried considerably. This image also enhances various other alluvial lowlands because their still-moist soils have low infrared reflectance and appear darker than the uplands. Thus, abandoned flood plains of the Mississippi River 8 and Ohio River 9 are re- vealed. Figures 146 and 147 show the St. Louis area and the junction of the Mississippi with the Missouri and Illinois Rivers. Figure 146 was taken be- fore the flood on Aug. 28, 1972. Figure 147 shows the flood swollen rivers on Mar. 31, 1973. Commonly it is not possible to obtain images that are contemporaneous with flood crests because of the 18-day ERTS cycle and cloud cover. Fortu- nately, images taken a week or more after a flood still provide faithful records of the flood inundation because areas that were flooded appear distinctly darker in the infrared bands (especially band 7) than the adjoining terrain and darker than they appeared in the preflood images. After a week or so, these areas gradually lose their relative darkness, and their boundaries become fuzzier. The slowness with which they fade suggests that the dark tones (low infrared reflectance) commonly are caused more by flood stress on the vegeta- tion than by moist soils. On Oct. 21, 1972, the Gila River in the vicinity of Saflord, Ariz., reached a flood stage of 2,322 m3/s, third highest on record, and caused about $10 mil- lion damage. Figures 148, 150, and 152 show conditions on Aug. 22, 1972, be- fore the flood. The inner cultivated part of the Gila River valley is the promi- nent arcuate light-toned band. Within this band, the Gila River appears as a sinuous thin dark line. Figures 149, 151, and 153 are the first postflood images of the same area, taken 11/2 weeks after the flood on Nov. 2, 1972. Note the greatly widened dark belt of reduced infrared reflectance along the Gila River. This belt corresponds with the zone that was inundated, as determined both by aerial photographs taken while the flood was in progress and by subsequent ground observations. Many hundreds of hectares of cropland were badly eroded and/ or covered by new deposits of gravel and sand. The areas of erosion and deposition show most clearly on band 5 as a light—toned strip inside the inundated belt that appears dark on the infrared bands. Thus, by comparing band 5 before- and after-flood images, a quick assessment can be made of the severely flood- ravaged land. Figures 154 and 155 provide a comparison with results from the humid Midwest. They were taken before and after the big floods of September 1973 on the East Nishnabotna and West Nishnabotna Rivers in southwestern Iowa. Figure 154 shows preflood conditions on Aug. 14, 1972; the other image mosaic (fig. 155) from Sept. 19, 1972, shows conditions 1 week after these rivers had inundated about 35,000 ha. The areas that were flooded still appear as con- spicuous dark bands because of their lowered infrared reflectance. These examples illustrate the usefulness of the repetitive, multispectral, and synoptic ERTS imagery, not only for monitoring flood inundation and damage but also for assessing the adequacy of existing flood-control struc- tures such as reservoirs, levees, and channelization. 00 I 0‘08: I I 00 I (3qu I am I swam: H089-30l ”1090-08 “BBS-Sm BSflHY73 C N37-37/H889-Bl N N37-35/H888-53 i188 M38-30l MOSS-00 3, Applications to Water Resources 14888-38I NBSS-BBI S-BBI H08 H08 -30| 7 D SUN EL58 92125 198-3987-N-I-N-D-IL NHSR ERTSBE-IZBS-ISBSZJ Bl APPROXIMATE SCALE 10 I I 10 20 30 MILES I I 30 KILOMETERS 199 FIGURE 144.—Annotated ERTS—1 image showing the confluence of the Mississippi and Ohio Rivers in flood on May 5, 1973 (1286— 16062, band 7). 08 I 00002 I I0” I flwDZ I00 I 000: I00 I (DI-I02 low I «IUDZ 200 ERTS-1, A New Window on Our Planet NB38-30l "4089-30 ”BBS-OBI MOSS-3% “BBB-BM ’.§(‘ 0’ - - | “BBS-BM NBSB-3Bl IBJUN73 C Nl3l'lIB-93g/36689-Bl N N37-3‘l/llll088889-532a ”SS 7 D SUN EL62 FIZI l4 196-4489-N-l-N-D-1L NRSH ERTS E-1322-16060-7 Bl APPROXIMATE SCALE 10 0 10 20 3'0 MILES i'I'H'Il I ll ll 10 o 10 20 30 KILOMETERS FIGURE 145.——Annotated ERTS—1 image showing the confluence of the Mississippi and Ohio Rivers as the rivers retreat to normal stage on June 10, 1973 (1322—16060, band 7). DO I 0002 I I00 I \IQDZ I 00 I @002 I Oh) I £01902 low I cnwsz IDS I £00382 .h MSZ-Ml 2851572 C N39-02/m91-08 N N39-02/lr891-82 "SlgSl APPROXIMATE SCALE 10 ii) 10 l CURE 146.—Annotated ERTS—1 image of the St. Louis area of Missouri, showing preflood conditions of the Missouri, Mississippi, and Illinois Rivers on Aug. 28, 1972 (1036-16162, band 7). INB‘lo-BB lNGSl-3B 14091-88 l 20 20 l I 30 KlLOMETERS 3, Applications to Water Resources “096-36 l 30 MILES 201 -38l LBSI-BGI H890- 7 D SLN ELSl H2133 l9l-OSBI-G-l-N-D-lL M69 ERTS E-lO36-16lgazl-7 B] on) I (.0qu I 00 I 0100: l I08 I mwaz low I 0082 00 I “(.08: I 81.0 I (00,82 I I 00 I (DQOZ I00) I 0082 202 ERTS—1, A New Window on Our Planet I N690— 30 H680 - 80 I N889 - 38 I ”4091-80 H096-3BI N09 -0 - 3II‘1FIR73 C MSG-5844689759 N N38-56/H889-5] I188 7 D SUN EL47 FIZIgG $é0-3489-N-l-N-D-IL NHSHuEaI§1$S3E0JI25PI APPROXIMATE SCALE 10 o 10 20 30 MILES l l | l I I I 10 0 10 20 3O KILOMETERS FIGURE 147.—Annotated ERTS—1 Image showing flood—swollen rivers in the St. Louis area on Mar. 31, 1973 (1251—16115, band 7). H588 '00I NB38-00I SI I5-7 BI I85 I (DQOZ I 00) I 00182 IUD I comm: A 1 ”HOS-30 APPROXIMATE SCALE 10 O 10 20 30 MILES 10 0 10 20 30 KILOMETERS FIGURE 148.——Preflood color composite ERTS—1 image of the Gila River valley of Arizona on Au 3, Applications to Water Resources MISS-Ml g. 22, 1972 (1030—17265). 203 '00 I 30382 lemz W'WD‘ZI [ODIMZ lam-0902 Imnwmz low a -——--—z 204 ERTS—1, A New Window on Our Planet MIN-00 HUB-30! APPROXIMATE SCALE 0 10 20 30 MILES I I I I I I I I 0 10 20 30 KILOMETERS FIGURE 149.—Color composite ERTS—1 image taken12 days after the flood shows the dramatic increase in the San Carlos Lake and the soil erosion areas upstream that resulted from the flood of Oct. 21, 1972 (1102—1 7274). I on) I W032 I am I uuoz 3, Applications to Water Resources 205 H] 10‘ m (gag-.glflllB-BZ N N33-42’dl'gg H55 7 D St]! ELSE flZl23 lg-IMIB-G-l-N-D-IL IBSH Em’gBSI-OQW-lmq OI FIGURE 150.——Preflood ERTS—1 image of the Gila River W2 C N33-MIIO-20 N N32-58/NIIG-l3 I153 7 D SUN valley of Arizona on Aug. 22, 1972 (part of 1030—17265, band 7). EL36 H2156 lW-l‘lZZ-G-l-N-D-IL WISH ERTS E-IlOZ-l7274-7 Bl APPROXIMATE SCALE 10 0 10 l 1 1 I l l I I l I I I I 10 0 10 FIGURE 151.——Postf|ood ERTS-1 image of the Gila Rive 20 30 MILES l J l 20 30 KILOMETERS r valley of Arizona on Nov. 2, 1972 (part of 1102—17274, band 7). 00 I 00—: I I DO I (1)0302 00) I £0sz I I00 I (.0002 I00 I (.0002 ISO I 00002 206 ERTS—1, A New Window on Our Planet , 4: 221672 éuflil313l:$/NIIO-02 N ”342%,”?8' I158 5 D SLN 5.5 fiZFZlamlgIMlB-G-l-N-D-ZL WISH flmfitlm-S 0| FIGURE 152,—Preflood ERTS—1 image of the Gila River valley of Arizona on Aug. 22, 1972 (part of 1030—17265, band 5). BZNOV'IZ C N33-BB/Nl 18-28 N N32-SB/Hl l6-l3 ”SS 5 D SLN EL36 92158 lw-MZZ-G-l-N-D-ZL MSG ERTS E-HBZ'WZ‘M-S Bl APPROXIMATE SCALE [0 0 10 20 30 MILES L1' 1 l 1 l I l l I ‘ ' ' ' I l I | 10 0 10 20 30 KILOMETERS FIGURE 153,—Postflood ERTS—1 image of the Gila River valley of Arizona on Nov. 2, 1972 (part of 1102—17274, band 5). DO I (DD—I: I I00 I (0qu on: I (.0002 I [00 I wwoz 3, Applications to Water Resources 207 lab) I “.502 I98 I —L'92 I80 I MLDOE I so I —ADZ N 0 4 B 3 8 I Oh) I #00: N097-WI mas—3m m-NI ”mo-w 149.1372 C W-SS/m-ll N W-W-BB I158 7 D SLN EL54 82130 lSl-m-G-l-N-D-IL WISH BUS [-1022-16384-7 0| APPROXIMATE SCALE 10 30 MILES _____J 10 —Annotated preflood ERTS—1 image of southwestern Iowa on Aug. 14, 1972 (1022—16384, band 7). IOOI—DOZ so I NJ‘DDE I IDU I 0582 N 0 4 I 3 0 208 ERTS—1, A New Window on Our Planet low I 0.502 I 00 I 04502 I 00 I —ADZ ISSEP72 C N4I~45/N095-55 N N‘H-‘IZ/WSS-‘I? nss 7 D SLN EL43 92144 ISI-BSBS-G-I-N-D-IL MSG ERTS E-IBSB-I6383-7 Bl ISSEP72 C ma—stuess-zs N N‘IB-IS/m-IB PISS 7 D SLN EL‘I‘I 92143 ISI-BSOS-G-l-N-D-IL M89 BUS E-I858-163%-7 OI APPROXIMATE SCALE 10 o 10 20 30 MILES I l 1 1 I I I I I ' I ' I I I I 10 0 10 20 30 KILOMETERS FIGURE 155.-—Annotated ERTS—1 image mosaic showing the West and East Nishnabotna Rivers in flood on Sept. 19, 1972 (1058— 16383 and 1058—16390, band 7). OPTICAL PROCESSING OF ERTS DATA FOR DETERMINING EXTENT OF THE 1973 MISSISSIPPI RIVER FLOOD By Morris Deutsch, US. Geological Survey 100d mapping by conventional methods is a time—consuming and expensive Fprocedure. Traditionally either ground surveys or black and white pan- chromatic aerial photography has been used as a basic tool in flood map- ping. Since the launch of ERTS—l, however, considerable interest has arisen in using ERTS data for flood applications. From some of the earliest data obtained by ERTS—l, Benson and Waltz (197 3) delineated and measured an area inundated by a severe local rainstorm near Aberdeen, S. Dak. Hallberg and others (1973) mapped the Nishnabotna River flood in Iowa with ERTS data collected 1 week after the flood. They also assessed the use of color-in— frared aerial photography versus traditional black and white panchromatic aerial photography for flood—mapping purposes and found the former to be highly superior. Morrison and Cooley (197 3) mapped inundation limits of the Gila River flood in Arizona from ERTS imagery and obtained good agree- ment with maps prepared from aerial photography and ground surveys. Early in March 1973, in anticipation of flooding along the Mississippi River, the US. Geological Survey made a special request to NASA for data from sub- sequent passes of ERTS—l over the Mississippi River valley. Basically, the objective was to map the extent of inundation as quickly as possible and with a minimum amount of conventional ground observations. It was surmised that specially processed ERTS data could provide hydrologists with a powerful new technique to supplement established methods of flood mapping, for the first time making it possible to map accurately the extent of flooding over very large areas, and to depict optically the flooded area. On March 31, ERTS—l provided the first synoptic view of extensive flooding along two large reaches of the Mississippi River, between St. Louis, Mo., and Natchez, Miss. On May 4 and 5, ERTS—l sensors imaged a strip of the Mississippi River reaching from midway between St. Louis and Cairo, 111., to New Orleans and the Gulf of Mexico. The flood was at its peak within the reach between Cairo and Memphis, having peaked at Cairo on May 4 at 4.48 m above flood stage. Figure 156, a set of mosaics prepared from band 7 images, shows the flood with the Ohio River to below its confluence with the Arkansas River. The inundation over a reach of the Mississippi River from above its confluence flood images (center) were obtained on March 31 and May 5 and were en- 209 210 ERTS—1, A New Window on Our Planet larged to a scale of 111,000,000. In order to determine the area inundated by any flood, obviously, it is necessary to have data on the area normally covered by water. For this critical analysis, preflood data collected by ERTS—l over the Mississippi River on Oct. 1 and 2, 1972, were used. The preflood mosaic (left) was also prepared from band 7 images. The difference in water-covered or wet surface, both in black, between October 1972 and the 1973 flood period is obvious. The extent of flooding can be color coded by projecting a preflood image and one collected during the flood into a single composite image. Band 7 was used because there is little or no reflection of incident radiation from water in this spectral region, and thus the water appears dark in a positive print. Display of the areas of flooding is shown on the right by a so—called “temporal composite” prepared by additive projection of the band 7 preflood images in red and the flood images in green. The composite covers the area of image overlap between the two dates. The composite shows excellent dif— ferentiation between dry soil, saturated soil, and standing water. In a proper- ly processed positive (Deutsch and others, 1973), standing water is very dark, dry soil is relatively light, and saturated soil is intermediate in density. When a nonflood image is projected as red, in register with a flood image projected as green, the composite color image is composed of the following elements: 1. Where there is surface water present in both images, the composite image receives little or no light and is therefore essentially black. This depicts the area normally covered by the river and other surface—water bodies. 2. Where the ground is not covered with water in both scenes, the composite image receives relatively equal amounts of red and green light and is therefore yellow. This depicts the area unaffected by flood waters. 3. Where there is surface water in the scene projected in green, and dry soil in the scene projected in red, the composite image receives only red light and is therefore a highly saturated red color. This depicts the area of flood inundation. 4. Where there is water-saturated soil in the scene projected in green, and dry soil in the scene projected in red, the composite image receives red light combined with a lesser amount of green light and results in a color on a continuum between yellow and red. Because available ERTS—l coverage is limited to cloud-free coverage once every 18 days, it cannot track the progress of a flood peak. Inspection: of data collected by ERTS—l on May 24, the day the Mississippi River re- ceded to bankfull stage at St. Louis, indicates that changes in surface—re- flectance characteristics caused by the flooding can be delineated, thus making it possible to map the total area flooded Without the necessity of a real time, continuous system to track and image the peak flood waves. Figure 157 shows an additive temporal color composite of band 7 images showing the extent of flooding in red on March 31 against normal surface-water distribution on Oct. 2, 1972. Flood stage was at about 11.58 m on March 31, but on April 28 the flood peaked at 13.2 m, obviously inundating additional areas not flooded on March 31. Figure 157 also shows a temporal color composite of the postflood (May 24) data at St. Louis against the October images. In this composite there are areas shown in red that are not shown on the March/ October tem- poral color composite. It is postulated that the later scene indicates changes in surface-reflectance characteristics caused by the flooding and that the area from which the flood waters receded between April 28 and May 24, including ponded flood waters, is depicted in tones of red. 211 3, Applications to Water Resources An v5.5 \wnoorlfiwwr ‘Kéwwlowwr £9570ri £9579ri "mnmr \m >32 vcm K “Ema. .mmrorlrmNr ‘55—. IFmNF €N$Flrmur \Nwwwrlrmmr ”mum; ‘5” :32 .K “Ema REST—Rev RUFF”: IKE. ‘FFSFIKE. "—0 tam "unar ‘N .50 K was: \vooorlonor \Soorlonor wmmhmsodx o2 _ _ _ mud—2 OOH om Om \mmoorlone‘ ~Nmoerlcn0r *0 tag 535 30:?» can o_mmoE mums: wtwanoo 5.00 Egon—hm... 22 .m 32 n. ma. Hm .55. 000..“— .mmm._a snooze: “mcoEucoU RES: ion—n $.85 33 £2 Em: 38.5 3.28: it "9550: we may.“ 26% 9 35°F. munch BuomEOu 5.8 .2an8 “5:388 2.8330 5:5 3.8qu .mnlmnmw $m__m> 82m in: -3922 .mbcou 9: wo 338E wwmcz Flmhzw too: was voozwilémr 550E 212 ERTS-1, A New Window on Our Planet APPROXIMATE SCALE 0 5 1o 15 20 MILES . . I - I I I I ' ' ' ' I I I I I o 5 1o 15 20 KILOMETERS I I I I 5 FIGURE 157.—-TemporaI color composite image of preflood October ERTS—1 image combined with March rood image (above) and May postflood image (opposite) of the St. Louis area (1071—16104, 1251—16115, 1305—16113, band 7). 3. Applications to Water Resources 213 APPROXIMATE SCALE 5 10 15 l l l l l I I 5 10 15 2o KILOMETERS 20 MILES o——o FIGURE 157.—Continued. MONITORING CLOUD-SEEDING CONDITIONS IN THE SAN JUAN MOUNTAINS OF COLORADO By Archie M. Kahan, Bureau of Reclamation search program, has installed seven ERTS data collection platforms (DCP’s) high in the rugged San Juan Mountains of southwestern Colo— rado (fig. 158). Here, amid wind-driven deep snow and intense cold, the plat- forms have proven to be extremely reliable communication tools (fig. 159). Weather information relayed rapidly by the data collection system (DCS) is incorporated in the decisionmaking process of the Colorado River Basin Pilot Project, a part of Project Skywater and the largest winter cloud- seeding research program in the Nation. Sensing devices linked to the platforms monitor precipitation, tempera- ture, relative humidity, insolation, ice riming, Wind direction, wind speed, snow water content, and streamflow (table 1). Data from each of the seven plat- forms are relayed to the satellite during each overhead orbit and then through Goddard Space Flight Center to a time-share computer in Denver where the data are translated into measured units and stored on file for access by users of Skywater’s Environmental Computer Network. The seven platforms, in remote regions accessible only by oversnow ve— hicles or helicopters, are being tested under severe environmental conditions to determine their operational suitability, maintenance requirements, reliabil- ity, and cost effectiveness. The seven platform sites are in a variety of terrains, but all experience severe weather. One, near the crest of Wolf Creek Pass, is in an area that re- ceived 1,500 cm of snow during the 1972—7 3 Winter. Winds in excess of 96 km/h are not uncommon, and temperatures plummet far below zero. Equipment failures were anticipated in this environment, but during the first season’s operation of the seven platforms, only one malfunction occurred, and it was caused by lightning. Meteorologists have gained much data from the system, although it is still being tested. During the spring of 1973, when spring snows raised the pos- sibility of floods in the valleys below, Project Skywater suspended the seed— ing project in a decision based, in part, on timely information provided by the ERTS DCS. Project Skywater, the Bureau of Reclamation’s weather—modification re- 214 loo-m2 loo-m2 3, Applications to Water Resources 215 N838-30l [MN-I HIO'I‘MI NIOT-fll 18mm C m#&m-% N N37-34/NIO7-32 "gm-9' D Sill ELSO RZI2O larfilllgzéalN-D-ILVMSR 5313512999536?!) 32 APPROXIMATE SCALE 10 0 10 20 30 MILES Li l 1 l | | | l | ' ' ' ' l l l | 10 0 10 20 30 KILOMETERS FIGURE 158.—Annotated color composite ERTS—1 image of the San Juan Mountain region of Colorado showing location of data collection platforms A (1299—17205). [W'm-I: ”lml 0:9:sz loo-m2 216 ERTS—1, A New Window on Our Planet FIGURE 159.——Wolf Creek Pass data collection platform. TABLE 1.—-Samples of Project Skywater DCS platform data 1 2 3 4 5 6 7 B 9 1o 11 12 13 100 6202 RUNPRK 110 DATE HHMM ss c TEM HUM WSP WDR TV0 TV0 Hsv BAv 120 °c % MPH DEG BIT BIT v v 130 FEB 19 74 0337 15 7 —11.8 117. 60.86 65. 2.00 1.0 2.5 13.0 140 FEB 19 74 0340 16 7 —11.6 37. 60.86 56. 1.00 1.0 2.5 13.0 150 FEB 19 74 0343 17 7 -11.6 87. 60.86 37. 1.00 1.0 2.5 13.0 160 FEB 19 74 0346 17 7 —11.6 87. 60.06 25. 2.00 1.0 2.5 13.0 170 FEB 19 74 0516 51 7 —11.6 85. 60.66 113. 1.00 0.0 2.5 12.9 180 FEB 19 74 0519 52 7 —11.6 05. 60.86 46. 2.00 1.0 2.5 12.9 190 FEB 19 74 0522 54 7 —11.6 86. 60.86 62. 1.00 0.0 2.5 12.9 200 FEB 19 74 0525 55 7 —11.6 86. 60.86 59. 1.00 0.0 2.5 12.9 100 6212 MULESHOE 110 DATE HHMM 55 c TEM HUM wsr WDR RAD ICE HSV BAv 120 °c % MPH DEG v v 160 JAN 4 74 0422 00 7 —14.5 13. 12.12 272 6.74 —2.5 11.9 12.3 170 JAN 4 74 0425 51 7 —14.3 13, 24.30 276 6.74 —2.9 11.9 12.3 1130 JAN 4 74 0429 35 7 —14.3 13. 10.97 205 6.74 —2.9 11.9 12.3 190 JAN 4 74 0433 1a 7 —14.7 13. 13.27 263 6.74 —2.9 11.9 12.3 200 JAN 4 74 0606 25 7 —14.1 13. 21.31 268 6.74 —2.9 11.9 12.3 210 JAN 4 74 0610 09 7 —-14.3 13. 12.88 291 6.74 —2.5 11.9 12.3 220 JAN 4 74 0613 53 7 ——14.5 13. 10.58 267 6.74 —2.9 11.9 12.3 230 JAN 4 74 1520 09 7 —15.7 13. 18.63 286 16.32 —2.9 11.9 12.3 Explanation of columns in table: 1, computer printout line num- ber; 2, transmitter ID no. followed by date; 3, hour and minute; 4, seconds; 5, quality check; 6, temperature ('C); 7, relative humidity (percent); 8, wind speed (miles/h); 9, degrees azimuth of wind direction; 10, either null (TVO) or relative measure of sky radiation; 11, either null (TVO) or relative measure of rime ice accumulation; 12, ‘/2 scale volt- age; and 13, battery voltage. The two DCP stations listed are Runlet Park and Muleshoe. HYDROLOGY OF ARID AND SEMIARID AREAS By J. Robert Owen and Lynn M. Shown, US. Geological Survey use are factors that influence runoff and sediment yield. ERTS imagery is particularly useful, compared to other methods, for discerning these characteristics when the area to be surveyed is larger than about 250 kmz. For areas of several thousand square kilometers or more, ERTS imagery pro- vides the most practical and rapid method of mapping these characteristics. Relationships between drainage-basin characteristics and hydrologic param- eters have been developed in a variety of climatic regions (Thomas and Ben— son, 1970). In arid and semiarid regions, for which hydrologic data on stream- flow and sediment discharge often are scarce or from widely scattered sites, the combined use of ERTS imagery and reconnaissance methods of estimating streamflow and sediment discharge can be a useful tool. Figure 160 is a color composite ERTS—l image that shows the canyon- lands of the Colorado Plateau and the confluence of the Green and Colorado Rivers in Utah. The area of the Book Cliffs and Roan Cliffs is deeply dis- sected rugged topography. The dendritic drainage pattern in the vicinity of Book Cliffs indicates that the surficial geology is fairly homogeneous. The lack of reddish color in the southwest corner of the Book Cliffs indicates sparse vegetal cover, the result of low annual precipitation and shallow soils. High sediment yields and rapid runoff would be expected in that area owing to moderate to intense rainfalls on steep unprotected slopes. The reddish color in the higher Roan Cliffs area indicates more plant cover. Better protection from erosion afforded by more plant cover results in less sediment yield (J. R. Owen, unpub. data) in spite of the steep topography. Linear drainage pat- terns in the Roan Cliffs area indicate more geologic structural control of stream channels than in the Book Cliffs area. An integrated channel system is another factor that determines the con— tribution from a source area to the water yield and sediment yield of a large drainage basin. Water and sediment from a source area generally do not leave the region when the channels are discontinuous or when flow is absorbed by dry channels and sediment is deposited during floods. For example, high sediment delivery could be expected in the area of the confluence of the Green and Colorado Rivers owing to the steep shale slopes and the well-integrated, continuous channel system. In contrast, only a few of the channels in the blue area at the base of the Book Cliffs are through-flowing to the main stream, Surficial geology, topography, type and quantity of vegetation, and land 217 218 ERT5—1, A New Window on Our Planet ROAN CLIFFS BOOK CLIFFS APPROXIMATE SCALE 10 20 I l I I 10 20 3o KILOMETERS 10 Illll IIIII 10 O—>—-O LA 5 L MOUNTAINS ‘1 1*. ,\ ’3 355:8 :83 ma; 3?: Lou—EEO”. PEM— co > 3995 via 2:0: 259: we coacmaxm v.53 -33 52:8 to. .632 £05 0E0; 250E 5 may: tca 993 c3383 85 -vcoammts 302 .2: .295 2.3 vmammt: 509+». :30 2) #5: Guam ammo c2995.... XIV 9mg dummm cwao cw>oEEE3 2; 30. 9.3.3 5): its“. -52 2% £080: £59: 23 \_m_bm=v:_-_m_u‘_vEEOu $383 53.5 .EflwEm _wx_n_ mafia—us: a; $6 583.”: EwEoE 233a .6553. mbm wco 35359. KMHMZOJEH _ O _ _ O _onE>m 595:. 2.0 .Sr 955 3:: firm Exé $2.3 «83.7.3 3 3:23 >18: 05 >2: $5 on 8:92.92 53 gm; 85. snow .Nnaw \em 2:. :o @2353 ‘mn Erlmocv «was: .2 Sat _S_m:u .occaum FImEm. co comma w. 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I :::Z\z\zz:\\\zzz £nt£i££1£t\\£tx .sszzz£1I \\:::::::::xxxf.h.mtz ::.\:E _xxzzxxzzua z: Exitzxxzzxzzzzx :~tx.mx.ttzxzzz .rzzu—aflun -zzzz zzzzzzzzxzozzzz duixzduzxttao _z\zxmm>-u udfiuzz z::z::zz:xz~z:z aanx auxzxzozzz I -..-, . .:. :‘: .54:::::::.:::: czzauuq>uuttzzt m Ev. owm OH mCON $2.3 hum « ,u WI m Ev. own on wCON 2H3 hum N um on, ERTS—1, A New Window on Our Planet 238 V . 6E: 859:8 Ho EE om Scan 5 $83 22 25 :o 8:533 225 A8; 25. .0: m5 3 E923 to 59.543.— .8 «EV. oomd Son< .mc: :53. .550 >65 5 .93; $50 >35 wcrcfimflu >3 ooofiwuv we 25% a “a $835.5 m_ QmE 9:. .wme_ Flmhzm w:€:om3t8 53> comtmaES 85563 2% up: Scafiwowoi 3.6m 3 0865:“. cam 05 mo 9:: 9.3-95. vow—EQUJEEEOQ a U6 tmmldow 550E, w4 mun-so mum: mums APPROXIMATE SCALE [0 0 1o 20 30 MILES l 1 I l l J l1 ' ll '1' l l l l 10 o 10 20 so KILOMETERS FIGURE 218.—Annotated color composite ERTS—1 image of the Yellowstone National Park and vicinity on Nov. 23, 1972 (1123— 17414); toelike projections of flows (f) can be seen on the Pitchstone Plateau. Imam loo-m 7. Applications to Conservation I4! lid-32H Hi iB‘BBl NG‘5-3Bl $4: “ ’V «‘0. \ law»mnm.c {mm . In nan? lemo- 5002 u l a e é 3 13 18* l Blogd'MOG-‘il an APPROXIMATE SCALE 10 20 30 MILES lO O 10 20 30 KILOMETERS FIGURE 219.——Annotated color composite ERTS—1 image of the Yellowstone National Park (outlined) and vicinity on Aug. 7, 1972 (1 01 5—1 7404). 314 ERTS—1, A New Window on Our Planet 111‘00‘ . f "l" ' _ Yde" Vrggll Y’ a _ g ‘. S YELLOWSTONE NATIONAL PARK YELLOWSTONE LAKE 10 MILES l l 10 KILOMETERS -—-l O—o—O FIGURE 220.—High—altitude color aerial photomosaic of the Yellowstone National Park (1969 NASA aerial photography). 7, Applications to Conservation 315 EXPLANATION 1'0 0 110 Wis l Thermal deposits and hydrothermally altered rocks I [I I II I I i l and soil, travertine, quartzite, and snow G'ml‘md 10 o 10 Kl LOM ETERS Dark rock, sand, gravel Grass and shrub mixture Water Grassland with 5 to 15 percent cover of conifers Coniferous forest with greater than 40 percent canopy cover Sparse vegetation on llzht rock or soil Coniferous forest with 15 to 40 percent canopy, and grass understory Dominantly light rock and soil Coniferous forest with 15 to 40 percent canopy, and light rock understory Shallow water and muddy water FIGURE 221.—Computer-processed terrain map of Yellowstone National Park made from computer compatible tapes for ERTS-1 image 1015—17404. THE GREAT DISMAL SWAMP OF VIRGINIA AND NORTH CAROLINA By Virginia Carter, US. Geological Survey 11 1972 Congress authorized the Department of the Interior to conduct a comprehensive 2-yr study of the Great Dismal Swamp and the Dismal Swamp Canal (Public Law 92—478). The study is designed to determine the desirability and feasibility of protecting and preserving the ecological, scenic, recreational, historical, and other valuable attributes of the Great Dismal Swamp and Canal and to consider the various alternatives for preser— vation in terms of effectiveness and cost. The study is being coordinated by the US. Fish and Wildlife Service. Several Federal agencies are participating in the Great Dismal Swamp study, including the US. Geological Survey, which is responsible for water dynamics, mineralogical data, and remote- sensing applications. On Aug. 31, 1974, President Ford signed the bill creating the Great Dismal Swamp Wildlife Refuge. During the next 3 yr, $7 million will be expended for land acquisition. The Great Dismal Swamp comprises approximately 850 km2 of wooded swamp and/or forested bog straddling the Virginia-North Carolina border. Because of the large size of the entire swamp and the inaccessibility of many interior parts, remote sensing meets the needs of both the current study and future research and management. It minimizes the extent of the ground work that is needed, allows for more rapid completion of inventory and mapping, enhances the ability to detect changes, and aids in detection of certain areas of special interest that would be likely to escape notice by conventional methods. The remotely sensed data used include NASA and US. Geological Survey aerial photography, ERTS data, and ERTS thematic extractions (Carter and Smith, 1973). These data were applied to: (1) overall study-area selection, (2) location of intensive-study areas, (3) hydrologic studies, (4) vegetation mapping, and (5) field studies, including identification of areas of special interest. The choice of the study area (fig. 222) by the US. Fish and Wildlife Service was made on the basis of both false-color infrared and black and white photographs and required approximately 3 man-weeks. ERTS imagery, on the other hand, later provided a synoptic picture of the entire Great Dismal Swamp and its geographic setting on just one ERTS frame. Figure 223 is an 316 APPROXIMATE SCALE 10 o 10 MILES I I I I l I J I l l l l I I 10 o 10 KILOMETERS FIGURE 222.—Map of the Great Dismal Swamp study area, Virginia-North Carolina. (Facsimile of a 1973 map prepared by the US. Fish and Wild— life Service, from US. Geological Survey data, in response to Public Law 92—478.) APPROXIMATE SCALE 10 0 10 MILES I I I I l I J I I I l I I I 10 O 10 KILOMETERS FIGURE 223.—Enlargement of part of a color com- posite ERTS—1 image (fig. 224) showing the Great Dismal Swamp (1205—15150). 35° 45' 36° 30’ 7, Applications to Conservation 76 ° 45' (is... it”; “ff." «\l V V‘ V 317 76°OO’ 318 ERTS—1, A New Window on Our Planet enlargement of a part of a color composite ERTS—l image (fig. 224) taken on Feb. 13, 1973. This image was used to reconfirm the choice of the study area. Comparison of this image with the map of the area (fig. 222) illustrates the utility of ERTS data in determining wetland boundaries. Delineation of the study area from the ERTS image would have reduced the time required for selection from 3 man-weeks to less than 3 man—days, including field checks. Many of the roads, canals, and vegetation associations can be clearly identified on a 1:250,000 enlargement of the ERTS image. Moreover, ERTS imagery can be used to construct a reliable map of similar large wetland areas without the need for either extensive 0r repetitive fieldwork or low-altitude aircraft cover- age. A preliminary analysis of ERTS digital data from CCT’s of the Feb. 13, 1973, Great Dismal Swamp image was made with the General Electric Co. IMAGE 100, an interactive multispectral analysis system that uses a television screen for displaying the results of the analysis. The thematic extractions shown are made by means of multispectral signature analysis. By using the spectral information in each MSS band, a signature can be derived for a selected condition or feature. and all other areas with the same signature can be detected. Figure 225 is a photograph of the interactive color display screen on which the digital data from part of the ERTS image are combined to give a simulated color-infrared picture of the Great Dismal Swamp. The canals, roads, and centrally located Lake Drummond can be clearly identified. Decidu— ous trees (blue), evergreen (red), and cultivated land, bare soil, or snow cover (white) can be identified. Figure 226 is a thematic extraction of Atlantic white—cedar, a commercially valuable tree species presently being lumbered in the North Carolina section of the swamp. Figure 227 is a thematic extraction of surface water below deciduous trees. The presence of surface water and maintenance of a high water table during the winter and early spring are essential to the continued survival of the swamp. Figure 228 is a thematic extraction of the drier deciduous areas of the swamp and the clearcut area where some snow remains on the ground. The swamp appears to be moving toward a drier condition, largely because of man’s continuing efforts at drainage. Area measurements of extracted themes can provide useful information to the resource manager. Monitoring the extent of surface water during the winter wet season is very important in assessing the results of water-level manipulation and modification of the hydrologic regime. Updating of tree- cover estimates is necessary periodically. Occasionally very large fires occur during the dry season, and measurements of areal extent of damage are im— portant in plans for revegetation. ISL-J I mmsz IEJLO I «#482 I'SJG) I mmsz 7, Applications to Conservation 319 :‘na UM? AWE-393 HE’S‘GBI NEWS-3m VIRGINIA ' WEBB-3W 2857-hl-i-IJ-D-2L NFISFI ERTS E'lZBS-ISISB“? 02 £97180! HE’S-Gel IEFEBT’E? C NBS~BBNB7S~20 N N38~@4/IJ@78'28 PISS D SUN EL32 HZI43 APPROXIMATE SCALE 10 o 10 20 30 MILES I 1 I 1 l I I I l ' l l I I I I 10 0 10 . 20 30 KILOMETERS FIGURE 224.—Annotated color composite ERTS—1 image of northern Pamlico Sound and the Great Dismal Swamp with a partial snow cover on Feb. 13, 1973 (1205—15150). 8U I 0')sz I I 00 I 01sz IDLJ I UIUOZ 320 ERTS—1, A New Window on Our Planet FIGURE 226.—Thematic extraction of Atlantic white-cedar in the FIGURE 225,—Color digital display of the Great Dismal Swamp Great Dismal Swamp. in simulated false-color infrared. FIGURE 228,—Thematic extraction of drier deciduous areas in FIGURE ZZZ—Thematic extraction of surface water below decidu- the Great Dismal Swamp. ous trees in the Great Dismal Swamp. APPROXIMATE SCALE 0 5 10 15 MILES I I 1 . 1 I | l l l l l l O 5 10 15 KILOMETERS / MONITORING BREEDING HABITAT OF MIGRATORY WATERFOWL By David S. Gilmer and A. T. Klett, US. Fish and Wildlife Service, and Edgar A. Work, Environmental Research Institute of Michigan migrating waterfowl, including wild ducks, brant, geese, and swans, are protected by treaties among the United States, Canada, Mexico, and Japan. The agency responsible for coordinating the management of this wild- life resource in the United States is the US. Fish and Wildlife Service. Assessment of breeding habitat is an important part of the management of waterfowl populations. United States and Canadian biologists have sug- gested that a significant correlation exists between the abundance of wetlands on the breeding grounds and the subsequent size of the continental duck popu- lation (Cooch, 1969; Crissey, 1969). The primary duck-breeding range in North America extends over the Dakotas, the southern part of the prairie provinces, northwestern Canada, and parts of Alaska. Because annual varia- tions in habitat quality in these regions greatly influence annual waterfowl population, in order to evaluate habitat conditions, the US. Fish and Wildlife Service makes low—level aerial surveys that sample approximately 2.2 million km2 of the breeding range during each spring and summer. Breeding pairs, broods, and wetlands are counted along preestablished survey flight lines. These data are used to estimate future waterfowl population by means of a mathematical model (Geis and others, 1969). This information is needed by resource administrators to establish annual waterfowl-hunting limits and regulations and other management policies. Biologists have speculated that aerial and satellite remote-sensing and associated data-processing techniques can be used to obtain accurate and rapid counts of wetlands over large areas of the waterfowl-breeding range. There- fore the service began an investigation of the feasibility of using remote- sensing techniques for waterfowl-habitat evaluation in 1968. Biologists at the Northern Prairie Wildlife Research Center in Jamestown, N. Dak., working in cooperation with the Environmental Research Institute of Michigan, Ann Arbor, Mich, conducted a series of tests using an airborne MSS for wetland mapping and land-use studies. The results of these tests demonstrate that airborne remote sensors could be used effectively to obtain regional wetland information and related data on surrounding land use, as well as to evaluate the waterfowl habitat (Burge and Brown, 1970; Nelson and others, 1970). Evaluation of ERTS MSS data has shown the utility of spaceborne sensors for evaluating waterfowl-breeding habitat (Work and others, 1973, 1974). ERTS test sites were selected in a region in North Dakota that con- tains some of the best waterfowl-breeding areas in North America. Figure 229 illustrates the coverage provided by three ERTS images obtained during May 1973 and July 1972 and 1973. A part of the Missouri Coteau is included in each frame. The Coteau is a region characterized by stagnation moraine and a nonintegrated drainage system that produces numerous small ponds and lakes. Magnetic tapes derived from telemetered satellite data for portions of Because of their free movement over and between nations and continents, 321 322 ERTS—1, A New Window on Our Planet each frame were processed by computer to obtain an enumeration of the wet- lands in the image. Comparisons were made to detect seasonal and annual changes. The ERTS image shown in figure 230 is a color composite of a scene Obtained on July 7, 1973. Varied land features, such as agricultural fields, and numerous water areas are evident. The ERTS tapes for this image were analyzed on a computer programed to recognize surface water. A 2389-ka part of the Coteau (enclosed by the dashed line) was selected to demonstrate this recognition capability. Table 2 consists of a size-frequency distribution of all wetlands recognized within the defined area. Additional data provided include the geographic location and size of each wetland; only a partial tabu- lation is given. Many water areas smaller than 1 ha are not recognized because of the sensor—resolution limitations, but new computer-processing methods and statistical-analysis techniques being evaluated are expected to provide infer— ential data regarding these small water bodies. TABLE 2.—Part of a computer printout for the luly 7, 1973, ERTS—1 image (fig. 230) showing size-frequency distribution of surface water and location and size of water bodies 07JUL13 C N47-22/5098-22 N N41-21/IO98-01 1349-16543- SUN E157 AlI31 192-4866-N 0-1-0-1 H ERIN (ERTS DATA! SCENE N.0. COTEAU LINES 1386 THRU 1428 POINTS 3 INRU 250 LINES 1429 ThRU 1452 POINTS 3 THRU 314 LINES 1453 VHRU 1499 POINTS 3 TMRU 498 SCENE AREAI 923 50. II. LINES 1500 TNRU 1511 ' POINTS 3 THRU 622 I 2389 50. ll. LINES 1572 THRU 2115 POINTS 3 THRU 741 DISTIIOUTIDN 0F NECOGNIIED EATER EDDIES TABULATION OF RECOGNIZED HATER BODIES 8V AKEA LAT LONG SCAN LINE POINT AREA IACRES) AREA IHECTARES) FREQUENCY 41.3110 99.4194 1439 194 .25 TO .50 .10 TO .20 0 47.3909 99.5535 1440 13 .50 TO 1.00 .20 TO .40 0 41.3733 99.4483 1442 156 1.00 TO 2.00 .40 TO .81 149 41.3637 99.4051 1446 216 2.00 TO 3.00 .01 TO 1.21 60 41.3668 99.4399 1449 110 3.00 70 4.00 1.21 10 1.62 41 41.3320 99.2560 1458 422 4.00 TO 6.00 1.62 10 2.43 65 47.3288 99.2353 1458 450 6.00 10 8.00 2.43 TO 3.24 29 47.3281 99.2403 1460 444 8.00 TO 10.00 3.24 10 4.05 21 47.3489 99.3953 1464 236 10.00 TO 15.00 4.05 10 6.01 38 47.3282 99.2599 1464 419 15.00 TO 20.00 6.07 TO 8.09 28 41.3190 99.2149 1467 481 20.00 TO 25.00 8.09 TB 10.12 10 47.3176 99.2053 1461 494 25.00 TO 30.00 10.12 TO 12.14 18 97.3268 99.2699 1468 401 30.00 TO 40.00 12.14 TO 16.19 14 47.3532 99.4564 1471 156 40.00 TO 50.00 16.19 10 20.23 11 47.3194 99.2509 1414 435 50.00 TU 75.00 20.23 TO 30.35 18 47.3164 99.2458 1471 443 75.00 T0 100.00 30.35 TO 40.47 16 47.3270 99.3193 1418 344 100.00 TO 150.00 40.41 TO 60.10 13 47.3201 99.2742 1418 405 150.00 TO 200.00 60.70 TC 80.94 7 41.3168 99.2521 147B 434 OVER 200.00 OVER 80.94 13 41.3637 99.5683 1480 8 41.3109 99.2291 1481 461 M 41.3089 99.2205 1482 479 47.3128 99.2606 1485 426 w_ 1.3125 99.2583 1485 429 'A‘U\na.25A«"hLiiaco4"‘h~132-\.‘~—‘NQ The synoptic evaluation of waterfowl breeding habitat using ERTS data can provide the US. Fish and Wildlife Service with a powerful tool in the effective management of our important waterfowl resource. Development of an operational system appears to be a realistic goal. for the near future. AREA 11cn551 20.861 1.093 1.093 1.333 11093 1.093 11.093 4.393 2.190 2.19. 3.295 2.193 4.393 1.093 2.196 1.093 3.295 3.295 1.093 4.393 3.133 3.295 1.093 2.193 1.093 9.334 21.453 ‘ "" 1.713 3 AREA (HECTARES) 3.445 .444 .444 3.111 .444 .444 .444 1.113 .009 .339 1.333 .339 1.113 .444 .339 .444 1.333 1.333 .444 1.110 3.550 1.333 .444 .339 .444 4.000 11.111 7, Applications to Conservation 323 Frame 1008-16594 c A N A D A I of July 1972 /Frame 1295—16550 of 14 May 1973 gevils Lakei ”\L\0 _| eLakota 1 . 1» _ ELSON .\ ' GM‘WORKSe I ‘~| Grand Forks _0 37:31:31: 7.11 D D Y? a \. ______ w Rockford [o— IJ—Im; —|- E -—- -, :Tmley . z I O f 2 I STEELEJ-"l TR I; m I: I ’ bor (8 . M. ._ —\ a, "P .\ 2 '\ A ""‘ Frame 1349—16543 Far 0° of 7 July 1973 i g9 Napoleon L o G 8324 G _____ o— 0 a 99° SOUTH DAKOTA APPROXIMATE SCALE 0 25 50 75 MILES r I 1 I II I I I7 ' ' ' I I I | 25 O 25 5O 75 KILOMETERS I 1 FIGURE 229.—|ndex map compiled from U.S. Geological Survey data showing coverage provided by three ERTS images in a primary waterfowl-breeding area in North Dakota. 324 ERTS—-1, A New Window on Our Planet DEV/LS LAKE . i i - \ 1AMI .\ it WV N MISSOUH Cotuou 4i!“ ‘Lgm‘ohh-‘hfl r‘-- ARIA MLR‘TED FOR COMPUTER ANAL} SIS APPROXIMATE SCALE 10 20 30 MIL ES 0 10 20 30 KILOMETERS FIGURE 230.—Annotated color composite ERTS—1 image 1349—16543 showing the waterfowl-habitat study area (dashed line) near Jamestown, N. Dak., on July 7, 1973, for which computer recognition of surface water bodies was obtained (table 2). Burge, W. G., and Brown, W. L., 1970, A study of waterfowl habitat in North Dakota using remote sensing techniques: Univ. of Mich.,Willow Run Labs., Tech. Rept. 2771—7—F, 61 p. Carter, Virginia, and Smith, D. G., 1973, Utilization of remotely sensed data in the management of in- land wetlands: Am. Soc. Photogrammetry, Sym- posium on Management and Utilization of Re- mote Sensing Data, Sioux Falls, S. Dak., 1973, Proc., p. 144—158. Chamberlain, B. B., 1964, 'These fragile outposts—a geological look at Cape Cod, Martha’s Vineyard, and Nantucket: Garden City, N.Y., The Nat. His- tory Press, 327 p. Cooch, F. G., 1969, Waterfowl-production habitat re- quirements: Canadian Wildlife Service Rept. Series, v. 6, p. 5—10. Crissey, W. F., 1969, Prairie potholes from a conti- nental viewpoint: Canadian Wildlife Service Rept. Series, v. 6, p. 161—1 71. Davis, W. M., 1896, The outline of Cape Cod: Am. Acad. Arts and Sci. Proc., v. 31, p. 303—332; also New York, Dover Pub., Geographical Essays, p.690—724,1954. Geis, A. D., Martinson, R. K., and Anderson, D. R., 1969, Establishing hunting regulations and allow- able harvest of mallards in the United States: Jour. Wildlife Management, v. 33, no. 4, p. 848— 859. Keefer, W. R., 1972, The geologic story of Yellowstone National Park: U.S. Geol. Survey Bull. 1347, 92 p. Nelson, H. K., Klett, A. T., and Burge, W. G., 1970, ' Monitoring migratory bird habitat by remote sensing methods: North Am. Wildlife and Nat. Resource Conf., Trans., v. 35, p. 73—84. REFERENCES Smedes, H. W., 1971, Automatic computer mapping of terrain: Internat. Workshop on Earth Re- sources Survey Systems, Proc., v. 2, p. 345—406. Strahler, A. N., 1966, A geologist’s view of Cape Cod: Garden City, N.Y., The Nat. History Press, 115 p. US. Department of the Interior, National Park Service, 1969, Cape Cod National Seashore, Massachu- setts: U.S. Govt. Printing Office, 2 p. Williams, R. 5., Jr., 1973, Coastal and submarine fea- tures on MSS imagery of southeastern Massa- chusetts: comparison with conventional maps: NASA Goddard Space Flight Center, Symposium on Significant Results Obtained from the Earth Resources Technology Satellite—1, 2d, New Car- rollton, Md., Mar. 1973, Proc., v. 1, sec. 8., p. 1413—1422. Williams, R. 5., Jr., and Friedman, J. D., 1970, Geologic mapping applications of coastal aerial photog- raphy, Cape Cod, Massachusetts [abs.]: Photo- gramm. Eng., v. 36, no. 6, p. 597. Work, E. A., Jr., Gilmer, D. S., and Klett, A. T., 1973, Preliminary evaluation of ERTS—1 for determining numbers and distribution of prairie ponds and lakes: NASA Goddard Space Flight Center, Sym- posium on Significant Results Obtained from the Earth Resources Technology Satellite—1, 2d, New Carrollton, Md., Mar. 1973, Proc., v. 1, sec. A, p. 801—808. 1974, Utility of ERTS for monitoring the breed- ing habitat of migratory waterfowl: NASA God— dard Space Flight Center, Symposium on the Earth Resources Technology Satellite—1, 3d, Washington, DC, Dec. 1973, Proc., v. 1, sec. B, p.1671—1685. 325 CHAPTER 8. APPLICATIONS TO OCEANOGRAPHY INTRODUCTION By William J. Campbell, US. Geological Survey erhaps in the whole field of geophysical investigations, the most difficult Prealm in which science is attempting to elucidate the cause and effect of nature is that of the oceans. This is so because the oceans not only cover most of our planet but also both within them and on their surfaces large-scale changes happen in a short time. For example, the wave structure of whole seas can be altered within a few hours by atmospheric forces, and parts of the arctic and antarctic sea-ice canopies move as fast as 50 km/day, and their areal extents undergo seasonal fluctuations of :20 percent and 85 percent, respectively. The numerical modeling of the physical and biological systems in the oceans is progressing rapidly and promises to give man his first, albeit rough, quantitative understanding of the complex web of oceanic phenomena upon which his very survival may hinge. But as the efforts to make a numerical model of the atmosphere have shown, the use of models is limited not by our lack of an understanding of the physics of the system but by our lack of detailed large-scale sequential data to apply to the models. It is precisely in meeting this profound need that space technology may render its greatest service. V'Vithout a doubt, the most detailed synoptic look at the oceans available to science is that given by ERTS—l. The value of these data is immense, and what follows in this chapter must be considered as simply preliminary and cursory examples of the use that can be made of them. The following ten papers are grouped into two sets: the first is made up of four papers on the study of turbid water, and the second includes six papers on sea ice. Carlson has shown how ERTS sequential imagery of suspended-sediment plumes in coastal waters can be used to define the seasonal variation of current direction in nearshore waters (1). 328). These measuren’ients are both diflicult and expensive to perform using standard shipboard observations. Further- more, ERTS imagery gives a truly synoptic view whereas shipboard observa— tions cannot. Coker and others have shown how ERTS imagery can be used to study the complex current structure of estuaries and the morphological changes of the bottom topography (p. 330). An important environmental finding of their work is that it may be possible, by using ERTS-type imagery and selected 326 8. Applications to Oceanography 327 ground information, to distinguish between natural and manmade turbidity in estuaries, information that is essential for assessing the impact of the great numbers of proposed industrial projects to be built on the Nation’s estuaries. Hunter has used ERTS imagery of turbid-water masses off the Texas coast to delineate the complex current patterns of the area (1). 334). He has shown that gyres and turbid plumes can be tracked for periods of several days with high-resolution imagery and that these data can be a valuable comple— ment to data obtained by ships. Campbell has combined ERT S, Nimbus—5 ESMR, and aircraft imagery of the sea-ice cover of the Beaufort Sea to study both its morphology and dynamics (p. 350). These combined data have given a new picture of this ice cover that could not have been drawn if the measurements were studied separately. The eastern Beaufort Sea is covered with large, round, multiyear ice floes, whereas its western sector and the Chukchi Sea are covered with small, fragmented, predominantly first-year ice. Campbell has shown how ERTS imagery can be used to track the motion of individual ice floes (p. 337). Such a technique. when applied to a large part of the ice canopy, will give invaluable data to test numerical models of the ice, such as those being developed by AIDJ EX. Campbell has also shown how the complex dynamics of the openings in the sea-ice canopy, leads and polynyas. can be monitored by ERTS (p. 340). The ERTS data, when acquired sequentially over large areas, will prove to be fundamental to thermodynamic studies of the ice cover. Campbell illustrates how the complex structure and dynamics of the sea—ice shear zone along the Arctic Ocean coasts can be measured by ERTS (p. 3346). Considering the intense push to explore this area for oil. long—term monitoring of the Alaskan and Canadian arctic offshore waters with ERTS— type imagery is essential. Campbell shows that seasonal morphological changes of sea ice can be measured by ERTS (p. 343). Barnes and Reimnitz show how spring floods along the northern coast of Alaska discharge onto sea ice at their months (p. 356) ; they also describe the effect of sea ice on sedimentological processes as seen in the synoptic view provided by ERTS imagery (p. 360). MAPPING SURFACE CURRENT FLOW IN TURBID NEARSHORE WATERS OF THE NORTHEAST PACIFIC By Paul R. Carlson, US. Geological Survey RTS provides an opportunity to study synopti- E cally seasonal differences in current direction in nearshore waters, an area difficult to study by ordinary oceanographic techniques. ERTS MSS imag- ery shows patterns of suspended sediment that can be used as indicators of the flow direction of the near- shore surface currents (figs. 231, 232). The flow direc- tions are determined by the shapes of the plumes of turbid water, which are elongate in the direction of flow and are especially prominent off the mouths of major rivers. Photographic interpretations of flow directions have been substantiated by the returns of drift drogues dropped off the mouths of the northern and central California rivers at the time of satellite overflights (Carlson and Harden, 1973). Turbid-water patterns in the nearshore zone around Cape Mendocino, Calif, can be clearly seen on the images for Jan. 6, 1973 (fig. 231), and Apr. 24, 1973 (fig. 232). During the winter and spring rainy season, most of the turbidity is due to large quantities of suspended sediment carried into the ocean by the streams and rivers originating in the California Coast Ranges. For example, the Eel River yields about 30 X 109 kg/ yr of suspended sediment, the highest aver- age annual suspended-sediment yield per square kilo— meter of drainage basin of any river in the United States (Brown and Ritter, 1971). Other sources of suspended matter and turbidity in the coastal waters are planktonic organisms, coastline erosion and sedi- ment resuspension by storm waves, and waste discharge effluents. During periods of high river discharge, how~ ever, the enormous quantities of suspended sediment discharged from the rivers generally mask these other sources. During January the flow of the coastal currents was generally northerly, but by April it had reversed and was generally southerly. This change in current direc- 328 tion in the nearshore“ coastal waters corresponds to the seasonal change of current flow observed in the offshore waters. Most of the year the surface flow is southerly (the California Current), but in the winter, owing to seasonal reversal of wind direction, a north- erly flowing current surfaces (the Davidson Current) (Schwartzlose and Reid, 1972). Complex flow directions that appear in both images around Cape Mendocino and Point Delgada may be due to zones of convergence and divergence. These zones apparently are related to oceanographic condi- tions such as upwelling, to localized wind motions, and/or to topographic features such as coastal irregu- larities and submarine canyons. The complex current patterns off Humboldt Bay are perhaps manifestations of the tidal circulation in this lagoonal system, and they are complicated further by the discharge plumes of the adjacent Eel and Mad Rivers and the complex submarine and coastal morphology. The January image (fig. 231) was obtained at the time of maximum tidal-flood current in Humboldt Bay. Turbid water, most likely from the Eel River plume, has been carried in the entrance of the bay and into the north channel. The April image (fig. 232) was obtained during ebb— tide conditions (about 2.5 h after maximum ebb) and shows a discrete plume of turbid tidal water outside the entrance to Humboldt Bay. The 18-day repetitive cycle of ERTS provides op- portunities to obtain seasonal coverage of the surface- current directions of nearshore waters along the Pa- cific coast of North America in spite of the seemingly ever—present cloud cover. Knowledge of the coastal currents is vital in coastal areas for proper planning by land-use commissions, for proper location of sew- age effluents by sanitation districts, for proper manage— ment of sport and commercial fishing, and for better understanding of ecological conditions. f '9 a Point Delgéfé‘o 8, Applications to Oceanography 329 APPROXIMATE SCALE [0 0 10 20 30MlLE$ I; 1 t 1 l l l J l I ' ' 1 l l l l 10 0 10 20 30KILOM£TERS FIGURE 231.—Winter ERTS—1 image of turbid-water plumes along FIGURE 232.——Spring ERTS—1 image of turbid-water plumes along the northern California coast on Jan. 6, 1973 (part of 1167— 18283, band 4). White masses at extreme left of image are clouds. The prevailing wind direction for January is from the southeast (NOAA, unpub. data, 1973). The suspended- sediment concentration in the Eel River at Scotia was 122 mg/l on Jan. 5. 1973, at 1610 h (U.S. Geological Survey, unpub. data, 1973). the northern California coast on Apr. 24, 1973 (part of 1275—18290, band 4). White masses at left edge are clouds. The prevailing wind direction for April is from the north (NOAA, unpub. data, 1973). The suspended-sediment con- centration in the Eel River at Scotia was 35 mg/I on Apr. 23, 1973, at 1615 h (U.S. Geological Survey, unpub. data, 1973). DETECTION OF TURBIDITY DYNAMICS IN TAMPA BAY, FLORIDA1 By A. Eugene Coker, Aaron L. Higer, and Carl R. Goodwin, US. Geological Survey 32.7 million t of total cargo are handled annually. In terms of export tonnage, the port is fourth in the country—10 million t annually. Through this port passes 50 percent of all the cargo tonnage in the State of Florida. This commerce provides $200 million per year in wages and salaries to workers in the Tampa area, $15 million to $18 million per year to the U.S. Government in the form of customs receipts, and, in addition, $50 million per year to the positive side of the important U.S. balance of payments ledger. In 1970, Congress authorized the deepening of the Tampa Bay channel (Rivers and Harbors Act of 1970) from 10.4 to 13.4: m. In order to determine the effects of this deepening on circulation, water quality, and biota during and after the construction, the US. Geo- logical Survey, in cooperation with the Tampa Port Authority, has collected data and developed a digital— simulation model of the bay. In addition to data collected using conventional tools, use is being made of data collected from ERTS— 1 (fig. 233). RBV multispectral data were collected while a shell—dredging barge was operating in the bay and were used for turbidity recognition and unique spectral signatures representative of type and amount of material in suspension. The processed data inte— grated with other modeled parameters provide a view of the dynamics of turbid material during dredging periods. A three—dimensional concept of the dynamics of the plume was achieved by superimposing the parts of the plume recognized in each RBV band. This pro— vided a background for automatic computer processing of ERTS data and three-dimensional modeling of turbidity plumes (Coker and others, 1973). The Port of Tampa is the 8th largest in the Nation; 330 Image identification was made by comparing ERTS—l transparencies (fig. 233), aerial photographs (fig. 234), maps, and field observations (fig. 235) of the bay with the velocity-vector grid (fig. 236). The relative size and shape of the turbidity plume is shown to the right of figure 237, as recognized in each RBV band. This system operates in three different spectral regions: the green band, 0.475 to 0.575 mm, band 1; the red band, 0.580 to 0.680 ,im, band 2; and the near- infrared band, 0.690 to 0.830 ,um, band 3. Organic detritus and clay particles make up most of the suspended particulate matter (turbidity) that re- sults from dredging operations in the waters of Tampa Bay. The water absorbs and reflects sunlight so that the RBV imagery depicts a signature indicative of the turbid condition of the water. The intensity of the reflection registered in the imagery will be modified by quantity and type of material in suspension, strati— fication, settling depth, type of bottom material, and water-surface roughness. If the water is clear or slightly turbid, the Sun’s energy that spans band 3 is mostly absorbed at the surface, and that of bands 2 and 1 will penetrate to progressively greater depths before being absorbed. For this water, the resulting tones on positive black and white images will be almost black for band 3 with progressively lighter, but still dark, tones for bands 2 and 1. The lighter tones are caused by the greater penetration and scattering (less absorption) of light from suspended particulate matter in the water and atmosphere at the shorter wavelengths of bands 2 and 1. Depending upon the span of energy (RBV band) , type of particulate matter, stratification, depth of settling, and bottom conditions, the more Fl:LVVork done in cooperation with the Tampa Port Authority, Tampa, law I (DNQZ I DO I LODGE DO I ONO: I I on) I 4'00! ”883-38 LESS-NI IMZS-w L882~38| #188??? OF MEXICO WGZ-EIGI l-N-D- NRSR ERIE '1’IB-IS333 81 L883-38l ”83%| BZFUTQ C FOB-04488268 N NZB-O‘ILBBZ-SS REV DXRI SLN ELSS RZI03 180-8l38-N- APPROXIMATE SCALE 10 0 10 20 30 MILES I l I 1 1 l l I I I I I I I I I I IO 0 10 20 30 KILOMETERS FIGURE 233,—Annotated color composite ERTS~1 RBV image of the Tampa Bay area of Florida (1010—15333). am I (DNGZI I00 I ~00: I 00 I (”~02 OOI WOZI 332 ERTS—1, A New Window on Our Planet I5 n w G ( I o k } (5; I 15 0?? oi ) 3 l ) 4| OI) 47 / () Ifio ( ,0 k 23 24 05; l5 l5 7 I )0 O 1 I) 0:2) 34 {£3 IO \ ‘ 0 4 no 2 5 40 If ( )0 /. U ‘ 04") Tampa Bay \ 25 IO / IOO z I. (I 64 1g. 7 22 I I 6"” lave 0-3 we??? 0‘ I/ II a EXPLANATION Mexico ‘ ' .13 O Turbidity (JTU) .. ‘3 sampling site Sampling depth ' 2.2 Top . .7 150Mmme l) '91 HO 1 1.8 Bottom 0:;) 2'8 32 ( ) Did not sample U Q 22 043 Sampling dates 0 June 26—27, 1972 . July 10—12, 1972 ‘ A JTU=Jackson 5. , Turbidity units CI) 2.4 fl APPROXIMATE SCALE 5 O 5 l I 10 KILOMETERS 10 MILES I I 0 5 FIGURE 234 (left).—Oblique aerial photograph of shell-dredging operations and turbidity plume. View looking southeast. US. Geological Survey photograph by Carl R. Goodwin. FIGURE 235 (below left).—Sketch map showing observations of turbidity in Tampa Bay. FIGURE 236 (below right).—Velocity-vector grid of turbidity in Tampa Bay. The barbs indicate current flow direction; the shaft lengths are proportional to current velocity. _,-a,¢ri , "r’a’I’I’ l \s\\‘\ Jul-‘— ‘ ‘~‘_‘.~\ ‘ ms“ \ \x\ s e - \§x§'\‘«~e ~ \ EXPLANATION Velocity vector ha---.—, ,z/ .rbbhn—d—fi—"’ ' A PPROXI MATE SCALE 5 lOMlLES 1 l l l l l l ' l ' I l l l 5 0 5 10 KILOMETERS 10 8, Applications to Oceanography 333 RBV I RBV 2 RBV 3 ’r s «9 :7' 13° TURBIDITY PLUME APPROXIMATE SCALE 0 10 20 30 MILES L1 1 1 1 l l l l l ' ' l l l I l l 10 0 lo 20 3O KILOMETERS turbid waters will be more reflective than the less tur- bid waters and will appear as lighter gray tones on the imagery. Assuming that the bay water is slightly turbid (fig. 235), a three-dimensional concept of the shape of the more turbid plume may be demonstrated by super— imposing those parts of the plume observed in all three bands (fig. 237). On both band 1 and band 2, positive images, the sediment plume is depicted by lighter gray tones near the center and darker tones of lower reflec- tance at the outer edges of the plume. The turbidity- plume boundaries in band 1 extend beyond those in bands 2 or 3 and may be areas of deeper settling depths and/or contain less particulate matter in sus- pension (fig. 237). The energy span of band 3 is mostly absorbed by water at the surface, and only the par- ticulate matter at the surface reflects light. The part of the plume at the surface may be delineated by FIGURE 237.——A black and white photograph of RBV bands en- hanced by a color-additive viewer and a sketch map of turbidity plume. lighter gray tones in the imagery of this band. This part of the plume may also contain recently suspended material that may be more highly concentrated. The movement of the plume toward the mouth of the bay is in response to ebb-tide conditions at the time of ERTS overpass. Before ERTS, the extent of dispersion of dredging silt plumes in an area as extensive as Tampa Bay (more than 770 km2) could only be made on a chart by con- necting stations having equal turbidity as measured in a massive sampling program, but the positions and number of transects for turbidity sampling did not usually allow complete synoptic coverage showing the dynamic distribution of the turbidity plume. Further- more, compared with ordinary massive sampling pro- grams, the associated field data needed for correlation with the ERTS imagery may be considerably reduced in number of transects and samples across the bay. MOVEMENT OF TURBlD-WATER MASSES ALONG THE TEXAS COAST By Ralph E. Hunter, US. Geological Survey the Gulf of Mexico near the Texas coast is well illustrated by the complex patterns in these two ERTS images (figs. 238, 239). taken on successive days in late fall 1973. Certain features of the system of marine currents over the inner Continental Shelf can be deduced from images such as this. For example, these images show plumes of turbid water from the tidal inlets being de- flected by southwestward coastal currents. Plumes formed by river discharge are similarly deflected. but individual river plumes are difficult to identify. Several fingerlike bands of turbid water not related to tidal inlets or river mouths can be seen projecting obliquely seaward from the nearshore zone of turbid water. Although evidence for the origin of these bands is not obvious in this image, studies of other images suggest that the bands can be related to flow direction in two different ways. Some bands of turbid water are parallel to the current; if the bands in this image are of this type, their orientation indicates that the flow was obliquely seaward. Other bands of turbid water are oblique to the current and are being gradually de- formed by current shear; if the fingers in the image were being sheared by a current flowing southwestward parallel to the coast, their orientation indicates that the velocity of the current increased in an offshore direction. Several gyres can be seen along the shoreward edge of the offshore mass of turbid water in figure 239. Their counterclockwise rotation indicates current shear in a left—lateral sense. Comparison of this image with one overlapping this area on the previous day (fig. 238) suggests that these and other features in the off- ‘l'he dynamic nature of turbid-water masses in 334 shore turbid-water mass remained identifiable while drifting during this time. The movement of these fea- tures indicates that the current was flowing southwest- ward approximately parallel to shore and that it ranged in speed from about 0.2 m/s at a distance of 25 to 30 km from shore to about 0.1 m/s at a distance of 50 to 60 km from shore. The greatest speed prob— ably occurred within the zone of clear water at a distance of 15 to 20 km from shore. Zones of rapid flow paralleling the shore, such as the one interpreted as occurring in this image, have been called coastal jets by some oceanographers. The evidence on current patterns furnished by remote-sensing data in areas of turbid water can be a valuable, complement to data obtained from the move- ment of surface and bottom drifters or drogues and from current meters placed at selected points over ex- tended periods of time. ERTS—l imagery has furnished valuable informa- tion on the sources, distribution, and movement of suspended sediment in the northwestern Gulf of Mexico; much of this information could hardly be ob- tained in any other way and certainly could not be obtained over such large areas at such frequent inter- vals other than by satellites. Measurements of current velocity from single images have proven possible where the place and time of origin of detached plumes from tidal inlets could be inferred, and measurements by time—lapse methods have proven possible in the areas of overlap between images taken on successive days. In addition, the patterns of turbidity variation in the imagery reveal a wealth of detail on current directions and relative velocities (Hunter, 1973). am I 0ND: I I00 I 1.0st I one I ONDZ I 00 I UILDD: 8, Applications to Oceanography 335 ”4895-88 N884-30l H084-BBI |N829-30 N883-30i “BBS-OBI H084 - 3m ”09“ ~08l 2|NOV73 C N28-43/N894-22 N N28-4l/N884-l7 H88 4 D SUN EL35 H2149 l89-8778-G-l-N-D-2L NRSH ERTS E-l486-18l73-4 0| APPROXIMATE SCALE 10 0 10 20 30 MILES |_L 1 1 I l l I I | ' l ' l l l l l 10 O 10 20 30 KILOMETERS FIGURE 238.—Turbidity patterns in the Gulf of Mexico and Galveston Bay on annotated ERTS—1 image 1486-16173, band 4, on Nov. 21, 1973. I00 I LONSZ I000 I ONGZ I00 ' EDNQZ low I LDNISZ law I LDNOZ I Ob) | ONGZ 336 ERTS—1, A New Window on Our Planet NBSS-BBI ”885-301 HBSS-BBI I San Luis Pass of Brazos River POSS Cavallo GULF OF MEXICO “836—38 I NBZB’BBI ”4096-88 HBSS-3Bl 22NOV73 C N28-48/N095-46 N N28'47/LJ885-41 I'lSS 4 D SUN ELB‘l H2148 l89-6786-G-l-N-D-2L NHSH ERTS E-1487-IBZ31-4 Bl APPROXIMATE SCALE 10 0 10 20 30 MILES l 1 1 l l l | I A l l l I l 1 l | 10 0 10 20 30 KILOMETERS FIGURE 239.—Turbidity patterns along the Texas coast between Galveston and Pass Cavallo on annotated ERTS—1 image 1487— 16231, band 4, on Nov. 22, 1973. I SO I LDNSZ I GLO | ONOZ I80 I ONDZ ne of the most difficult measurements in the 0 study of sea ice is to track accurately the tra- jectory of specific floes. Until very recently the only means of doing this was to have men live on them and make frequent celestial navigational fixes— a very costly, inefficient, and inaccurate approach. Re- cent experiments by the AIDJEX using unmanned drifting buoys tracked by the Interrogation, Record- ing, and Location Subsystem on Nimbus—4 have shown that accurate trajectories can be obtained in this way, but the initial cost and emplacement of these buoys are expensive. A recent paper by Campbell and others (1973) has shown how ERTS images can be used to track ice floes, and how images can help interpret data on drifting ice floes obtained from unmanned drift buoys. In this study two large ice floes in the eastern Beau- fort Sea in the Arctic were tracked for the period from Aug. 2 to Sept. 24, 1972, on sequential ERTS imagery of the area. The two floes tracked are shown in figure 240, an ERTS image acquired on Aug. 19, 1972. These were large ice floes measuring 13 X28 km (upper right) and 16x27 km (right center), and existed at the edge of the icepack, which was made up of predominantly big floes of about the same size. The trajectories of these floes, as measured from five sequential ERTS images (Aug. 2 and 19 and Sept. 4, 21, and 24, 1972) are shown in figure 241. The two floes drifted in a similar fashion, and considerable rela— tive strains (relative displacement between two floes) occurred. During the August 19 to September 4 drift, the floes converged with a strain rate of 35 percent TRACKING ICE FLOES BY SEQUENTIAL ERTS IMAGERY By William J. Campbell, US. Geological Survey (percentage of spatial displacement between floes within a given time interval) in 15 days (2.33 percent per day), and during the September 4 to 21 drift, they diverged with a strain rate of 26 percent in 17 days (1.53 percent per day). Much open water bordered these floes during this period, which allowed the ice- pack to deform easily, but such large strains have also been observed deep within the arctic ice cover. During the 40 days that these two floes were being observed, only one underwent any weathering; about 20 percent of its area was broken off. Both of these floes were composed of multiyear ice generally 3 to 4 m thick. These measurements illustrate the extremely dy- namic nature of the arctic ice cover. ERTS is provid- ing the first high-resolution imagery that permits sea—ice dynamics and deformation to be accurately measured over wide areas. These data are funda- mentally important in the development of numerical models to predict sea-ice dynamics, and if man is ever to operate ships safely in the Arctic Ocean, it will be necessary that such data be acquired on a regular real- time basis. A recent study by Weeks and Campbell (1973) has suggested the possibility of towing antarctic icebergs to selected sites where they could be used as a water resource. In order to do this, however, it would be necessary to locate and track icebergs of the desired size in the antarctic seas. ERTS imagery has been used by Hult and Ostrander (1973) to study the mo- tion of antarctic icebergs. This study has shown that ERTS is an excellent means of studying antarctic iceberg formation and motion. 337 019 I 80—}: I I09 I .DNIDZ 00 I ‘00—}: I IOU I 0-402 00 I Nw-‘E I 338 ERTS—1, A New Window on Our Planet ”4129-06 ”1128-60 N074-BBI HIZS-GBI HIZS-MI I ' ”“3 ' ”HEM-90 INIZS'W ISHUG72 C N73-20/HI28‘33 N N73'15/N128'23 ”SS 6 D SUN ELZS FIZI76 2|2'B378'H'I'N'D'2L NFISFI BUS E'1827'202‘II‘6 8| APPROXIMATE SCALE IO 0 10 20 30 MILES l L 1 l 1 l l l J l I I ' I l I I l 10 0 10 20 30 KILOMETERS FIGURE 240.—ERTS—1 image of ice floes in the eastern Beaufort Sea on Aug. 19, 1972 (1027—20241, band 6). I 00 I UlN—E I00 I (Ll-402 I00 I GIN—Z I000 I Nqaz 00 I \lN—E I 8, Applications to Oceanography 339 75° N BEA UFOR T Ice floe trajectories in figure 240 70° N 155 APPROXIMATE SCALE 0 100 200 300 MILES I l I I I I I I I I I l I I I I 100 O 100 200 300 KILOMETERS FIGURE 241.——Map showing trajectories of the two ice floes shown in figure 240 (Aug. 2, 1972, 1010—20293; Aug. 19, 1972, 1027— 20241; Sept. 4. 1972, 1043—20125; Sept. 21, 1972, 1060—20070; and Sept. 24, 1972, 1063—20241). Other numbers (1—6, 8) and trajectories show movement of unmanned drifting buoys tracked by Nimbus—4. ICE LEAD AND POLYNYA DYNAMICS By William J. Campbell, US. Geological Survey 11 order to test any numerical model for the dynamics and thermodynamics I of ice—covered oceans, it is necessary to acquire sequential synoptic imagery of the changes in the thickness of the ice cover and its fracturing under the influences of the forces operating upon it: air stress, water drag, internal ice stress, Coriolis force, and gradient current forces. High-resolution imagery is especially important for testing models based on floe-to-floe interactions. The only existing remote-sensing satellite that provides imagery having sufliciently high resolution is ERTS. All the remote-sensing plans for AID- J EX, whose main experiment will take place from the spring of 1975 to the spring of 1976, call for the use of all ERTS imagery obtained of the Arctic Ocean ice cover. Although ERTS cannot directly measure the thickness of the ice cover, it can be used to distinguish between classes of ice thickness and to monitor changes within each class. In figure 242, a section of the ice cover of the Arctic Ocean deep within the Beaufort Sea is shown. At the time this image was obtained, a light wind was blowing on the surface from the northeast. Large floes of first—year ice or multiyear ice (the whitest ice seen in the image), which vary in thickness from approximately 1.5 to 3 m, can be seen separated by refrozen polynyas filled with gray ice, which is 20 to 40 cm thick. Also, numerous new leads can be seen that are either open or have very thin ice covers (a few centimeters thick) on them. In the center of the image, a large refrozen polynya that runs approximately north-south is composed of two distinct zones of gray ice that have been formed by two separate opening events of the original lead. Figure 243 shows approximately the same area 1 day later, during which time a moderate wind continued to blow from the northeast. Strong divergence of ice has occurred, and the large polynya has increased in Width, the new lead on the eastern side of the polynya having expanded approximately 4 km. Within this polynya, four distinct zones can clearly be seen: (1) a zone of open water immediately adjacent to the eastern edge of the polynya, (2) a zone of thin gray ice formed very recently by the freezing of the grease ice (ice slush), (3) a zone of earlier formed gray ice 20 to 40 cm thick, and (4) a zone of older gray ice 40 to 60 cm thick. A significant internal ice stress has oc- curred, causing strong deformation in the period between these images, as shown by the recent fracturing of the gray ice in the polynyas. When ERTS images such as these are combined with surface measure- ments, as they will be during the main AIDJ EX experiment, they will give invaluable information needed to test prediction models for sea-ice dynamics and thermodynamics. 340 I80 I (0.5—: IQO I .hfi—Z I DO I (II-JO: 00 I GIL—t I ”149-381 | INB'IS-OO HMZ-BBI ”SS 6 D SUN ELZB 92183 2I8-3572-H-l-N-D-2L NRSH ERTS E-1256-21391-6 8| APPROXIMATE SCALE 10 20 0 l l l IIIIII l 0 FIGURE 242.—ERTS—1 image of the ice cover in the central Beaufort Sea on Apr. cated by arrows. 8, Applications to Oceanography 341 N078-68l ”1138-00 30 MILES I I I 10 20 30 KILOMETERS 5, 1973 (1256—21391, band 6); Polynya is indi- IOD I Old—E 08 I \IU—Z I '00 I U'INIOZ IUD I cow—z I00 I 0.5—: uifikll I” ' GIL—t "IMI IDOIOJ-‘l: laid»: 342 ERTS—1, A New Window on Our Planet NIfiZ-BBI HMO-OBI N876 - 80 l I00 I (DU—E I00 I 03‘: 46-60l N075-BBI ”I‘M-Gm 4 N75-3l/H142-3l ”SS 6 D SUN EL2| HZIBS 218-3588-fl-l-N-D-2L NHSFI ERTS E-1257-21445-6 Bl APPROXIMATE SCALE 10 20 30 MILES I l I A l 10 20 so KILOMETERS 10 lllll pill 10 0—0—0 FIGURE 243.— ERTS—1 image of the ice cover in the central Beaufort Sea on Apr. 6, 1973 (1257—21445, band 6), 1 day after figure 242 was imaged; large polynya is indicated by arrows. SEASONAL METAMORPHOSIS OF SEA ICE By William J. Campbell, US. Geological Survey a short time, it also undergoes significant seasonal changes; especially significant is the change that occurs when winter ice metamorphoses into summer ice. During most of the year, a strong temperature gradient exists in the ice cover that acts as a thin insulating veneer about 3 to 4 m thick. The ice cover separates two fluids at distinctly different temperatures— the sea water having a typical surface temperature of — 1.7°C and the surface air temperature during the winter of —30° to —40°C. In the summertime the ice becomes isothermal, and many melt ponds form on its upper surface that are important both for thermodynamic and morphologic reasons. Because they cover from a fifth to a third of the total area of the ice cover at the peak of the summer melt period, the melt ponds are a major item in determining the summertime heat balance of the ice cover. \Vhen they refreeze, they form lenses of relatively homogeneous ice with fairly uniform salinity within ice floes having a varying vertical structure. In figure 244, a very large area of sea ice in the eastern Beaufort Sea is shown before the onset of the summer melt. Five very large ice floes, with approximate dimensions of 40x50 km. are seen to be composed of cemented pieces of very thick ice. The leads and polynyas that appear gray are covered with gray ice from 20 to 40 cm thick, whereas those that appear black prob— ably have no ice on them. In figure 245, the same area of sea ice is shown 17 days later. During the period between these images, the segment of sea ice has undergone translation within the Beaufort Sea with a net movement to the west of approximately 30 km. Over the entire area of sea ice, numerous melt ponds have now formed. It is difficult to estimate visually the total area covered by the melt ponds, but it is about 20 to 30 percent. (One could make a more accurate estimate by using density~slicing techniques.) It can be seen that by the time of this image, all the gray ice observed earlier had melted, and the entire icefield is now made up of thick ice floes. The large floes visible in the earlier image can clearly be seen to have undergone no weathering, and therefore probably the greater part of the ice seen in these images is multiyear sea ice with an average thickness of 4 In. Another interesting thing that can be observed by comparing these two figures is that little deformation occurred during the 17 days between observa- tions. The relative positions of all the major floes are the same, and therefore the ice has not been subjected to any strong shearing or stretching deformation. These images clearly show that the sequential synoptic high-resolution capability of ERTS will provide invaluable data on sea—ice dynamics and morphology on both a day-to-day and a seasonal basis. N ot only does sea ice undergo large dynamic and morphologic changes in 343 344 ERTS—1, A New Window on Our Planet HIM-WI HIE-OBI [WIS-N I—nua—l: loo-M2 Int”: lu-m—t Iu-Na—l: loo-M2 1m C ITI-WHISZ-fl N m-mm-a I” S D an 5.! l2]. m-fi'l-l-I'D'I W ERTS E‘ln-ZITH-S II I -.| - OBI mum C m-Q‘I’HITI-II N Ive-muss“! & 6 D an 5.3 Ml”w—&-fl-l-N-D-£It%fl HTS E- Isa-amps OI APPROXIMATE SCALE 10 0 10 2o 30 MILES 10 o m 20 30 KILOMETERS FIGURE 244.—ERTS—1 image mosaic of large ice floes in the eastern Beaufort Sea on June 16, 1973, before onset of the summer melt (1328—21374 and 1328-21381, band 6). I-o-m—l: loo-loo—l: loo-NZ Int”: loo-w: ale-“2| I-lw-t Ina-an: I-IIJ—E 8, Applications to Oceanography 345 “um—El I-lw—t IDOIw—E ”INII nun C m-Mlal-Zl I m-Mla-S ms C D u as Ml! m-‘H-fl-l-N-D-L In EI'II E-IK-ZHIS-O .2 “[173 I: “’wgk I m-WMIS‘I ms 3 I) an afifimgfimS-fl-l-I‘D-l I" an E-IM-Zlui-B Q APPROXIMATE SCALE IO 0 10 20 30 MILES 20 30 KILOMETERS IO 0 IO FIGURE 245.——ERTS—1 image mosaic of large ice floes in the eastern Beaufort Sea 17 days after the image in figure 244 (1345—21315 and 1345—21321, band 6). |DOIMZ loo-WI: IGOIMAF: 09-th loo-Inu—z IODIMZ I...W= locum—x: DYNAMICS OF ARCTIC ICE-SHEAR ZONES By William J. Campbell, US. Geological Survey Canada, varies in width from several kilometers to several hundred kilometers and on the average closely corresponds to the width of the Continental Shelf. It is within this shear zone that all the offshore exploration for oil will occur in the foreseeable future. In addition, all proposed arctic shipping must use this same zone. For these reasons, interest in the ice-shear zones in the Beaufort Sea has grown steadily and has resulted in the formation of two international programs to study the morphology and dynamics of arctic sea ice, AIDJEX and the Polar Experiment. Scientists involved in these large—scale studies think that more knowledge of the ice—shear-zone dynamics is of fundamental importance for understanding the dynamics of the ice cover on the interior part of the Arctic Ocean. ERTS imagery has provided valuable information on the morphology and dynamics of the arctic ice-shear zone. In figure 246, a section of the north- west coast of Banks Island, Northwest Territories, Canada, is shown with its adjacent shear zone. At the time this image was acquired, a strong surface wind was blowing straight off the coast toward the ice, and a recently opened lead can be seen along the entire segment of the coastline. Between the recently opened shore lead and the consolidated pack ice, which is approximately 25 km away, a band of gray ice has formed in the previously opened shore lead. Figure 246, therefore, shows three distinct zones of ice: (1) the shore lead in which frazil ice (groups of needlelike. crystals of ice) and grease ice (ice slush) are forming; (2) a zone of recently formed gray ice approximately 20 km wide, which is probably 20 to 30 cm thick; and (3) large consolidated floes of first-year ice, which are probably 1.5 m thick. In figure 247, the same area is shown approximately 24 h later. The offshore wind continued to blow, and the first-year ice zone is being moved farther offshore, moving about 14 km in 1 day. The gray ice has undergone rafting in several places where the lighter colored bands can be seen running parallel to the shore in the gray-ice zone. The shore lead has remained open along the entire segment of coast, and ice plumes of grease and frazil ice can be seen forming. Figure 248 shows the same area 17 days later. During this period the first-year ice has been strongly moved to the southwest, and the gray—ice zone is now approximately 40 km wide. At the time this image was obtained, the wind was again blowing offshore, and a recently formed shore lead can be seen. The gray—ice zone by this time was 20 to 30 cm thick, and pieces of shore—fast ice have been stripped off the coast and are adrift in the shore-lead zone. The first-year ice in the northeastern segment of the coast has been pushed strongly against the coast and has undergone heavy fracturing, form- ing many floes. Thus, the ERTS images clearly show the extremely dynamic nature of the ice-shear zone and its concomitant complex morphological changes. T he arctic ice-shear zone, which borders the northern coast of Alaska and 346 8, Applications i0 Oceanography 347 u 5 £5 3 -OBI 75- HI . IBFPR73 C HTS-Ml 2% N N75-32/H122-23 Pg so D SIN ELR 321% g? l-fi-l-N-D-ZL WISH ERTS E-l28l-2I243-S OI APPROXIMATE SCALE 10 30 MILES 10 0 10 20 30 KILOMETERS FIGURE 246.—ERT —1 image of the northwest coast of Banks Island, No thwest Territories, Canada (1261—20243, band 6), Apr. 1 1973. 348 ERTS—1, A New Window on Our Planet I00 I ON—Z I00 I —N—E DO I 01-402 I H I 2 2 B B I 00 I UN”: IHIZS- H 7-09 M HS 2L M58 ERTS E-lZSZ-Zm-S BI IN] -08 I I IN] - IIH’R73 C Nfi-gfllfi-OI N N75-32/HI23-4 S 6 D SW EL22282%3 2|8-3655-FI-l-N- APPROXIMATE SCALE 10 10 20 30 MIL ES LLhHTF—‘r—J—F—‘IJ—é lO 0 10 20 30 KILOMETERS FIGURE 247.—ERTS—-1 image of the northwest coast of Banks Igland, Northwest Territories, Canada (1262—20302, band 6), 24 h after fig e 246 was imaged. 8, Applications to Oceanography 349 low I m——E ISO I LN—E Oh) I (”#02 I law I 07-482 I 00 I (JIM—E H l 2 8 B 0 DO I muoz | HIZS-Nl HIZG-WI mars-ea UIZZ-WI 28FPR73 C N75-45/NI22-I3 N N7S-48/Nl2l-57 ”SS 6 D SLN EL28 RZISS 2|8-3892-H-I-N-D-2L M59 ERTS E-l278-28242-6 0| APPROXIMATE SCALE 10 10 20 30 MILES 10 0 10 20 30 KILOMETERS FIGURE 248.—ERTS—-1 image of northwest coast of Banks Island, Northwest Territories, Canada (1279—20242, band 6), 17 days after figure 247 was imaged. MORPHOLOGY OF BEAUFORT SEA ICE By William J. Campbell, US. Geological Survey ea ice is the most dynamic solid feature on the Earth’s surface. At any S given moment, sea ice covers approximately 13 percent of the Earth’s ocean area. Because of the increased scientific awareness of the important role sea ice plays in determining the polar heat balance, and thus the climate of the Earth, major international research programs such as the AIDJEX and the Polar Experiment have been formed to expand scientific studies of the dynamic and thermodynamic interactions of ocean, ice, and atmosphere. ERTS imagery has been used by AIDJ EX to study the morphology and dynamics of sea ice in the Beaufort Sea. Campbell and others (1973) have shown how a variety of measurements from ERTS—l, Nimbus—4, and Nimbus— 5 satellites, when used jointly with data from aircraft and drift stations, show that the morphology of the ice cover of the Beaufort Sea is not uniform and is more complex than hitherto realized. As an example of the use of imagery, on Aug. 22, 1972, ERTS—l obtained images in both the eastern and western Beaufort Sea. Figure 249 is a mosaic of ERTS imagery of an area 160x480 km in the eastern Beaufort Sea. Large round ice floes cover most of the area, 10 being more than 35 km across and some being as large as 55 km across. These floes can be identified in images obtained a month earlier, and, in the summer period between these observations, the images show that the floes underwent little weathering while moving toward the southwest. The longest sequence of ERTS—l images covering one section was from Aug. 17 to Sept. 24, 1972, and consisted of five passes over an area just east of that shown in figure 249. The shape and size of the large floes observed in the eastern Beaufort Sea resemble those of major floes shown in microwave images obtained in this area during the 1971 AIDJEX—NASA Remote Sensing Experiment (Gloersen and others, 1973). Also on Aug. 22, 1972, 200 min after the images comprising figure 249 were obtained, ERTS—l passed over the western Beaufort Sea and obtained the images shown mosaiced in figure 250. The most striking difference between this mosaic and figure 249 is the complete absence of any big floes. The mean size of the floes in the western area is more than an order of magnitude smaller than those in the eastern area; typical floes are 1 to 2 km across. Also, they are not round but have angular fragmented shapes. It is important to bear in mind that these mosaics show ice floes at the same latitude and are essen- tially synoptic. The shape and size of these small angular ice floes in the western Beaufort Sea resemble those of ice floes shown in microwave images 350 3-“;sz :w - -III I...n~mz .I-m—Il 1.9.”: Iceman—g Inna“: ll. . 99—: I0:- hu—n 2mm C m-MIZS>Q N m-MIZS-Q [SS 5 D SI EL27 MIN ZIS-B‘fl-Wl-WD‘Z. m ms E-lu-Zfl‘lrfi II ZZKISTZ C N7}I‘I|vll32-$ N muzwm—‘s ’55 6 D 5.! ELZU HITS ZIZ-I‘ZI’R-l-N-D-l "‘51 Bus E~Im-lel2-S Bl HI -BI turn» I u —-I 7I- l ZMT’Z E Y'i-MUS-g N I? *Mlfi-E W 5 Fan E13 HZI73 ZlB-O‘Z‘l-I‘l-hN-ll-l naflms ~ln-ZI‘IS-S 0| mum m o In to so was so KILDIIEI'EIS ”Hue-ll Iu-uu—g i é Imam-40: u-w-zl ”-60le ..,.~_:. a-v-u-zi In. - mun—z l..- ”to: u.~4-:I roaring—I: wu ‘ «1-49:- 8. Applications to Oceanography 351 FIGURE 249.—ERTS—1 image mosaic of the eastern Beaufort Sea on Aug. 22, 1972 (1030—20410, 1030—20412, and 1030—20415, band 6). 352 ERTS—1, A New Window on Our Planet obtained in the same area during the 1972 AIDJEX—NASA Remote Sensing Experiment (Campbell and others, 1973). Figure 251 shows a mosaic of ERTS—l images obtained on Sept. 8, 1972; the area is slightly east of that shown in figure 249. From surface measure- ments of drifting buoys of the AIDJEX-Interrogation, Recording, and Loca- tion Subsystem, we know that the ice shown in this image was positioned 95 km to the east on Aug. 22, 1972. The floes in the western part of this mosaic resemble the many small floes visible in figure 250, but in the south-center section a band of larger rounded floes is seen. Therefore, the ERTS images give us a picture of the southern Beaufort Sea in which the eastern sector is made up of large rounded ice floes, the western sector is made up of small angular floes, and the central sector is made up of small floes and a few larger rounded ones. From the fact that the large rounded floes in the eastern sector were tracked throughout the summer with ERTS images and underwent very little weathering, we can surmise that they were multiyear ice floes having average thicknesses of 3 t0 4 m. But we cannot, using ERTS alone, accurately determine the age and type of ice shown in the central and western Beaufort Sea. The 1971 and 1972 AIDJEX—NASA Remote Sensing Experiments showed that multiyear ice has a “cool” radiometric signature in the 1.55-cm wavelength, whereas first~year ice has a “warm” microwave radiometric signa— ture. The ESMR mounted on the Nimbus—5 satellite is providing synoptic images of microwave emissions at this wavelength over the entire globe, and one of these images of the Arctic on Jan. 11, 197 3, is shown in figure 252. If one looks at the Beaufort Sea area in this image, one can see that, according to the ESMR, the ice in the eastern Beaufort Sea has a “cool” radiometric signature (blue) and is therefore multiyear ice. The image also shows that the ice just north of Alaska in the western Beaufort Sea is made up of pre- dominantly first-year sea ice because it has a “warm” (yellow) radiometric signature. Data such as these are fundamentally important if science is to develop predictive numerical models for the arctic ice cover, models which are necessary in order to utilize properly the oil and mineral resources in this highly vulnerable and dynamic region. FIGURE 250.—ERTS—1 image mosaic of the western Beaufort Sea on Aug. 22, 1972 (1030-22243 and 1030—22250, band 6). Ian . 948x tau-«No2 “mm—:1 am- lm—zl Ian-4h“! Inlu—K ”1159'. “1157-. m C m-MIS?" I m-Mlfl-fl ls - ””53- 2a”??? 32-2l/Hlfl-3 N "72-284" ‘32 N 8, Applications to Oceanography HIS“~I IRIS-u D u EIJ7 Hi7? ZIS-HZI-R-I-I-D-L m m E-lu-m-S DI - - I HI - I D 504 43‘5sz- 2II-D‘21ARHIIS-L-RZL m ERTS E-lm-ZZZQ-gm AmoxmAVE scAL: no 30 MILES m 20 an mounws 353 mu , was: as - mun—:1 Ilsa - Nwz an ‘ «IUI#X I QN'mmng ova-«Nazi mm . min—1: Isa . nun—x: Ian - uwz law . Nun: 354 ERTS—1, A New Window on Our Planet FIGURE 251.—ERTS—-1 image mosaic of the eastern Beaufort Sea area on Sept. 8, 1972 (1047—22181, 1047—22183, and 1047—22190, band 6). ISE-wm—L lam-«Na: ”Dayan—l: Ins: hqnz Koo ‘ —m—: a" . mm—z Isa-dul—E mo . «um—u: II an ELIs A2134 ZIB- n-I-u-n-ZL m FR‘rs E-IOQ7-22I8rs a: ”12 C m-Mls-fl l m-Mls-I PH 3 m1! C W'MISQ-Il N m-MISQ‘BZ PS 5 D sun in HZISI ZIS-W-H-I'N'D'l m9? EETS E'IMTZZIBTS 8‘ 1 - I HI - l - | uls‘l-aal m C m-11/ulsl‘rfiesvm-nazuns7-as ffi % an M m RZI‘IB leegfi' ‘l-N'D-Z. “SR ERTS E-IB‘7-22IW-6 EV APPRoxmsz SCALE an MILES 30 KILOMETERS mo . mil—l: mu - ~49: um - mm—c an ~ was»: I 1512 , mm<106 m3, dis- regarding drainage and subsequent river flow. Rapid snowmelt from May 24 through May 27 is indicated by the in- creased definition of the drilling pads at Prudhoe Bay (fig. 255). The sharp northeast—southwest lineation in the oilfield is due to downwind eolian trans- port of loose sediment from the roads and pads. Examination of earlier imagery of the area to the southeast of the Saga- vanirktok River and later imagery of the area to the northwest indicates that the rivers of the Alaskan North Slope overflow in sequence from southeast to northwest, apparently in response to the variance of solar insolation at dif- ferent latitudes. River flooding of sea ice marks the abrupt change from winter to sum- mer conditions in the Arctic when man’s transportation activities must shift from overland to air or water. Thus, knowledge of this phenomenon is essen- tial for the safe utilization of installations on or near deltas, and ERTS imagery provides a tool to determine the variability of the areal extent and intensity of flooding from year to year. Three overlapping high—latitude ERTS images show a 4—day sequence of 356 8, Applications to Oceanography 357 HM‘I-Cl U l 4 9 3 2W3 C "69-354" - - Im-3IMI47-wlqfiégé' B D SUI ELM HZ!” aggaggé-fl-I-N-D-ZL man ERTS giggPAIIZI-S 0| APPROXIMATE SCALE 10 0 10 20 30 MILES 10 0 10 20 3O KILOMETERS FIGURE 253.—Annotated ERTS—1 image showing an area of river flooding (arrow) on sea ice near Prudhoe Bay, Alaska, on May 24, 1973 (1305—21121, band 6). WI—MOZI “ISM—:I Um I ~U'I-‘E mi—WZI 358 ERTS—1, A New Window on Our Planet INNS-03 WHO-GD 10 [1111 11111 10 1973 (1307—21231, band 6). O—‘—O IHM‘l-BO HMS-OBI 26Hfl¥73 C PUB-lglfllfBO-IS N ITO-481H147-58 hSS 8 0 SUN EL‘IB gé?;§agé7'4283-fl-Ivflq-Zia MSR ERTS IEH-iggégglfll-S 8| APPROXIMATE SCALE 1? 20 30 MILES l J I l I 10 20 30 KILOMETERS FIGURE 254.—Annotated ERTS—1 image showing an area of river flooding (arrow) on sea ice near Prudhoe Bay, Alaska, on May 26, IOU ' 0402 Q0 ' ULD—E I DO I (Db—Z I ISO 3 OM02 QO‘NUl—‘E'I lawn—«102 [DO I “5102 I DO | com—x: zvnnvn c m-ssxhfilisqzsigeil 8, Applications to Oceanography 359 INNS-80 INNS-88 “147-“ HISl -80| HI am IN - N m-svums-zz [18$ 6 D SJN ELQB F|2l72 297‘4ZSilo4i-l—N-D‘1 Mg 3T5 E-lm‘ZIZSB-S BI APPROXIMATE SCALE 0 10 20 30 MILES 1 l l J I ' l ' ' I l l i o 10 20 30 KILOMEIERS FIGURE 255.—Annotated ERTS—1 image showing an area of river flooding (arrow) on sea ice near Prudhoe Bay, Alaska, on May 27, 1973 (1308—21290, band 6); drilling pads indicated by smaller arrow west of Sagavanirktok River. OD ' "QOZ I IOU ' Nib—E on: I 8‘102 I I SO ' OLD—l: INFLUENCE OF SEA ICE ON SEDIMENTARY PROCESSES OFF NORTHERN ALASKA By Erk Reimnitz and Peter W. Barnes, US. Geological Survey fiuence on the sedimentary environment of the Continental Shelf north of Alaska. An under- standing of this environment is of great scientific in- terest, for about 25 percent of the world’s Continental Shelf areas are seasonally covered by ice today; sea ice was even more widespread during colder periods in the past. Comprehension of this type of environment can be directly applied during future offshore development of the Prudhoe Bay oilfield. Figure 256 is an ERTS MSS color composite image taken on June 14, 1973, about 2 weeks after the river flooding of the fast ice (sea ice anchored to the coast or bottom) but 3 weeks before the breakup of the ice. With the initiation of river flow, extensive regions of fast ice are inundated by river water that carries some sediment onto the ice (Barnes and Reimnitz, 1972 and this volume; Reimnitz and Bruder, 1972). By the time this ERTS image was taken, most of this water had drained from the ice through strudel (drain holes in ice), producing bottom-scour features on the sea floor (Reimnitz and others, 1974). The outer boundary of the flood of river water can be detected in some areas (arrows). The ice near river mouths has melted (dark- blue area) ; from later images and ground observations, we can conclude that, at the time of sea—ice breakup, little of the river-supplied sediment remains on the ice to be rafted away from deltas. The location of the shear line between the fast ice and offshore pack ice has pronounced influence on sedi- mentological processes of the Continental Shelf. In in- terpreting ERTS images made during the period from March through June 1973, we find that initially the shear line lies between the 10- and 20-m depth con- tours along the north coast of Alaska. On the June image (fig. 256) the midwinter location is indicated The ice cover of the Beaufort Sea has a critical in- 360 by a solid line. Seaward of this line is the shear zone in which the ice is intensely deformed and shows a dense pattern of major pressure ridges. Ice movement in this zone occurs mainly during the first half of the Winter. Since the keels of many pressure ridges extend to the sea floor, the bottom is ploughed during such movement of ice. Eventually the pressure ridges be- come so firmly grounded that the ice in the shear zone becomes strongly resistant to further deformation, thereby causing a seaward extension of the fast ice out to 20 to 25 km along a relatively straight coastline. Overlapping ERTS images of late May 1973, taken at a time of strong easterly winds, show that a new shear line has formed (May position plotted as dashed line on fig. 256) with rapidly moving ice to the seaward of the line. Pressure-ridge lineation, which records the deformation of winter ice, is best seen in the right part of the image (fig. 256). Surveys of the sea-floor bottom made after the sea- ice breakup show sea-floor gouges produced by ice in this zone of major pressure ridges and a remarkably smooth bottom in the area landward of the shear line (Reimnitz and Barnes, 1974). Box cores from the shear zone show that sediments are intensely mixed (Barnes and Reimnitz, 1974). The keels of pressure ridges in the shear zone, Where they are in contact with the bot- tom, may afi’ect water circulation on the Continental Shelf. Obviously the shear zone will be the most haz- ardous region for any offshore construction. Our studies of ERTS images indicate that in some areas the shear line migrates seaward during the winter. Whether it initially forms within the same depth range year after year remains to be determined, but in the eastern part of the image in figure 256, where the shear line passes near outlying islands, its location apparently is controlled by bathymetry. ”um—t! lwl-fi-z loo-m I000”: 3, Applications to Oceanography 361 “ISO-Cl HMS-Cl C: «4 ) Ck kumm APPROXIMATE SCALE 0 10 20 30 MILES | 1 1 1 ll I l ll I 10 O 10 20 30 KILOMETERS FIGURE 256.—Annotated color composite ERTS—1 image of the Prudhoe Bay area of Alaska on June 14, 1973 (1326—21284). The outer boundary of the flood of river water is indicated by arrows. Location of shear line in midwinter is shown with a solid line, and the new shear line is shown with a dashed line. laid-Db: ”IWI. I lacuna—z REFERENCES Barnes, P. W., and Reimnitz, Erk, 1972, River over- flow onto the sea ice off the northern coast of Alaska, Spring 1972 [abs.]: Am. Geophys. Union, E635, Trans., v. 53, p. 1020. 1974, Sedimentary processes on arctic shelves off the northern coast of Alaska: Arctic Inst. North America, Symposium on Beaufort Sea Coastal and Shelf Research, San Francisco, Calif., 1974, Proc., . p.439—476. Brown, W. M., III, and Ritter, J. R., 1971, Sediment transport and turbidity in the Eel River basin, California: U.S. Geol. Survey Water-Supply Paper 1986, 70 p. Campbell, W. J.; Gloersen, Per; Nordberg, William; and Wilheit, T. T.; 1973, Dynamics and morphol- , ogy of Beaufort Sea ice determined from satel- lites, aircraft,'and drifting stations: NASA God- dard Space Flight Center, X—650—73—1 94, 20 p. Carlson, P. R., and Harden, D. R., 1973, Principal sources and dispersal patterns of suspended par- , ticulate matter in nearshore surface waters of the northeast Pacific Ocean, Type. I Progress Report to NASA, Period 1 June—15 Aug. 1973: U.S. Dept. Commerce Natl. Tech. Inf. Service E73—11099/ WR, 14 p Coker, A. E, Higer, A. L, and Goodwin, C. R, 1973, ."'Detection of turbidity dynamics in Tampa Bay, Florida, using multispectral imagery from ERTS— " « 1: NASA Goddard Space Flight Center, ., Sym- ‘ posium onaSignificant Results Obtained from the Earth Resources Technology Satellite—1,2d, New Carrollton, Md. Mar. 1973, Proc., v. 1, sec. B, p. 1715—1726. 362 ERTS—1, A New Window on Our Planet Gloersen, Per; Wilheit, T. T.; Chang, T. C.; Nordberg, William; and Campbell, W. J.; 1973, Microwave maps of the polar ice of the Earth: NASA God- dard Space Flight Center, X—652—73—269, 38 p. Hult, J. L, and Ostrander, N. C., 1973, Applicability of ERTS for surveying Antarctic iceberg resources: The Rand Corp., Final Rept. R—1354—NASA/ NSF, 50 p. Hunter, R. E., 1973, Distribution and movement of suspended sediment in the Gulf of Mexico off the Texas coast: NASA Goddard Space Flight Center, Symposium on Significant Results Obtained from the Earth Resources Technology Satellite—1, 2d, New Carrollton, Md., Mar. 1973, Proc., v. 1, sec. B, p. 1341—1348. Reimnitz, Erk, and Barnes, P. W., 1974, Sea ice as a geologic agent on the Beaufort Sea shelf of Alaska: Arctic Inst. North America, Symposium on Beaufort Sea Coastal and Shelf Research, San Francisco, Calif., 1974, Proc., p. 301——353. Reimnitz, Erk, and Bruder, K. F., 1972, River discharge into an ice covered ocean and related sediment . dispersal, Beaufort Sea, coast of Alaska: Geol. Soc. America Bull., v. 83, no. 3, p. 861—866. Reimnitz, Erk, Rodeick, C. A., and Wolf, S. C., 1974, Strudel scour: a unique Arctic marine geologic phenomenon: Jour. Sed. Petrology, v.44, no. 2, p. 409—420. Schwartzlose, R. A, and Reid, J. L.,1972, Near-shore circulation in the California Current: Calif. Ma— _ rine Resources Comm. CalCOFI Rept. 16, p. 57-— 65. Weeks, W. F., and Campbell, W. J., 1973, Icebergs as a fresh water source—an appraisal: Jour. Glaciol- ogy, v. 12, no. 65, p. 207—234. ‘1? U.S. GOVERNMENT PRINTING OFFICE : 1976 0—21 F907 7 DAY §LA Hydrologic Assessment of the ‘ September 14, 1974, Flood 1n Eldorado Canyon, Nevada GEOLOGICAL SURVEY PROFESSIONAL‘PAPER 930 Prepared in cooperation with the U .5. National ‘Park Service was 1975 CG“ M EUOCUMENTS DEPARTMENIE E OCT 1 51975 ' I E LlUn‘A 3; I, UNIVERSITY OF RCAUFQ} ?‘I3_ ”,5 ‘H- W“ A HYDROLOGIC ASSESSMENT OF THE SEPTEMBER 14, 1974, FLOOD IN ELDORADO CANYON, NEVADA A Hydrologic Assessment of the September 14, 1974, Flood in Eldorado Canyon, Nevada By PATRICK A. GLANCY and LYNN HARMSEN GEOLOGICAL SURVEY PROFESSIONAL PAPER 930 Prepared in cooperation with the U .8. National Park Service A presentation of hydrologic data and interpretations, eyewitness accounts of destruction, and documentation of flooding UNITED STATES GOVERNMENT PRINTING OFFICE,WASHINGTON:1975 UNITED STATES DEPARTMENT OF THE INTERIOR ROGERS C. B. MORTON, Secretary GEOLOGICAL SURVEY V. E. McKelvey, Director Library of Congress Cataloging in Publication Data Glancy, Patrick A. A hydrologic assessment of the September 14, 1974, flood in Eldorado Canyon, Nevada. (Geological Survey Professional Paper 930) Bibliography: p. 27—28. Supt. of Docs. No.2 119.16z930 l. Floods~Nevada—Eldorado Canyon. 1. Harmsen, Lynn,joint author. II. United States. National Park Service. III. Title. IV. Series: United States Geological Survey. Professional Paper 930. GBlZ25.N3G55 551.4’8 75—619132 For sale by the Superintendent of Documents, US. Government Printing Office Washington, DC. 20402 Stock Number 024—001—02692—9 CONTENTS Page Page Abstract __________________________________________________ 1 Runoff—Continued Introduction ______________________________________________ 1 Runoff volume ________________________________________ 10 The setting _________________________________________________ 2 Measured streambed and high water profiles ____________ 10 History ______________________________________________ 5 Flood frequency and magnitude ________________________ 10 Basin characteristics __________________________________ 5 Similar floods ________________________________________ 12 Slope _____________________________________________ 5 Sediment ________________________________________________ 14 Geology _________________________________________ 5 Sediment deposits ____________________________________ 14 Vegetation _______________________________________ 7 Sediment transport characteristics ______________________ 16 The storm ________________________________________________ 7 Erosion ______________________________________________ 21 Runoff ____________________________________________________ 8 Estimated landscape denudation ________________________ 24 Flow rates ____________________________________________ 8 Acknowledgments ________________________________________ 24 Flood wave characteristics ____________________________ 9 References cited __________________________________________ 27 ILLUSTRATIONS Page FRONTISPIECE: Aerial view of Eldorado Canyon looking upstream (west) on September 30, 1974. FIGURE 1. Photographs of flood-damaged trailer, truck, and boats ____________________________________________________________ 2 2. Map showing location of area described in this report ___________________________________________________________ 3 3. Map of Eldorado Canyon basin showing major tributary subbasins, area-altitude distribution, and location of streamflow estimate sites _____________________________________________________________________________________________ 4 4. Graph showing longitudinal profiles of main drainage channels ___________________________________________________ 6 5. Photograph showing eastward aerial view of lower Eldorado Canyon ______________________________________________ 6 6. Graph showing maximum water discharges in relation to drainage areas in the United States _____________________ 9 7. Photographs of Eldorado Canyon mouth during late stages of floodflow and during postflood excavation of flood sediment deposits ___________________________________________________________________________________________________ 11 8. Photograph of wave-cut bench (above debris line) along east shore of Lake Mohave _________________________________ 12 9. Graph showing trace of Lake Mohave stage at Davis Dam _______________________________________________________ 12 10. Vertical aerial photo of the terminal reach of Eldorado Canyon drainage and adjacent drainages on September 20, 1974 __ 13 11. Graph showing estimated flood hydrograph for September 14, 1974, near mouth of Eldorado Canyon _________________ 15 12. Map of flood boundaries, streambed profile line, and specific cultural features ______________________________________ 16 13. Graph showing profiles of peak discharge high water lines and streambed at slope-area site in Eldorado Canyon ________ 18 14. Graph showing profiles of peak discharge high water lines and streambed, Eldorado Canyon Resort _________________ 19 15. Downstream (eastward) aerial photograph of Eldorado Canyon terminus taken September 17, 1974 _________________ 20 16. Photograph of heavily damaged trailer park at Eldorado Canyon Resort ___________________________________________ 20 17. Map showing sediment deposits and locations of preflood and postflood shorelines _________________________________ 22 18—28. Photographs showing: 18. Excavated sediments quantitatively described in table 5 ____________________________________________________ 23 19. Stratified sediment deposited at the mouth of Eldorado Canyon ____________________________________________ 24 20. Floating debris at the mouth of Eldorado Canyon _________________________________________________________ 25 21. Downstream view of boulder deposits that probably moved on September 14 in Techatticup Wash ________ 25 22. Large boulder that probably moved during flood in lower reaches of Eldorado Canyon _______________________ 25 23. Position of high water line at canyon narrows just upstream from former restaurant ________________________ 26 24. An automobile at rest in lower Eagle Wash after about a l-mile transit in flood ______________________________ 26 25. Evidence of intense rill erosion in unnamed tributary to lower Eldorado Canyon ___________________________ 26 26. Evidence of minor channel flow and only minimal rill erosion in Copper Canyon ___________________________ 27 27. Highway damage in Techatticup Wash caused mainly by lateral channel scour _____________________________ 27 28. Windrows of boulders bordering a pre-September 14, 1974 erosion scar _____________________________________ 27 VI l CONTENTS ‘ TABLES Page TABLE 1. Approximate area-altitude distribution of Eldorado Canyon basin _________________________________________________ 5 2. Summary of hydraulic data resulting from peak-flow estimates ___________________________________________________ 8 3. Floods having peak flows per unit drainage area greater than that of Eldorado Canyon _____________________________ 12 4. Estimated nonorganic sediment deposits _______________________________________________________________________ 14 5. Approximate particle-size distribution of sediment samples _______________________________________________________ 15 CONVERSION FACTORS For those readers who may prefer to use metric units rather than English units, the conversion factors for the terms used in this report are listed below: Multiply English unit By To obtain metric unit Length inches (in.) __________________________ 25.4 ___________ millimetres (mm) __________ .0254 ___a__s____ metres (m) feet (ft) ____________________________ .3048 ___________ metres (m) yards (yd) __________________________ .9144 ___________ metres (m) miles (mi) _________________________ 1.609 ___________ kilometres (km) Area square feet (ftz) ______________________ .0929 ____________ square metres (m2) acres ______________________________ 4047 ___________ square metres (m2) square miles (mi?) ___________________ 2.590 ___________ square kilometres (kmz) Volume cubic feet (ft3) _______________________ 28.32 ___________ cubic decimetres (dm3) ____________ .02832_-_________ cubic metres (m3) cubic yards (yd3) ____________________ .7646 ___________ cubic metres (m3) acre—feet (acre-ft) ___________________ 1233 ——————————— CUbiC metres (m3) F low feet per second (ft/s) ________________ .3048 ___________ metres per second (In/S) cubic feet per second (fta/s) .......... 28.32 ___________ litres per second 0/8) miles per hour (mi/hr) ______________ 1.609 ___________ kilometres per hour (km/hr) Mass ‘ tons (short) _________________________ .9072 ——————————— tonnes (12) Density pounds per cubic foot (lb/fta) _________ 16.02 ___________ kilograms per cubic metre (kg/m3) A HYDROLOGIC ASSESSMENT OF THE SEPTEMBER 14, 1974, FLOOD IN ELDORADO CANYON, NEVADA By PATRICK A. GLANCY and LYNN HARMSEN ABSTRACT A devastating flash flood of thunderstorm origin struck Eldorado Canyon, a 22.9-square-mile drainage with a history of flooding, in southern Nevada, at about 2:30 p.m., September 14, 1974. The flood killed at least 9 people, destroyed 5 trailer homes and damaged many others, obliterated a restaurant, destroyed 38 vehicles, 19 boat trail- ers, 23 boats, half of the boat-docking facilities, and the gas dock. The severe runoff resulted from intense basinwide rain and hail at rates up to 3 inches of precipitation per half an hour. The storm moved downba- sin and generally increased in intensity, which compounded runoff rates. Peak discharge was estimated to be 76,000 cubic feet per second just upstream from the developed area near the canyon mouth. About 2,000 acre-ft of runoff reached Lake Mohave, the canyon terminus. Runoff dumped an estimated 70,000 cubic yards (about 100,000 tons) of inorganic sediment in Lake Mohave and throughout the lowermost canyon reach. It also delivered an estimated 4 acre-ft of organic or floating debris to Lake Mohave. The inorganic sediment was esti- mated to be less than 1 percent boulders, 40 to 60 percent gravel, 20 to 40 percent sand, and 10 to 25 percent silt-clay. Although the recur— rence interval for this magnitude runoff is great, a similar flood could occur in any given year. These types of flash floods, although common in the desert southwest, are not fully understood and are frequently ignored, and therefore the danger to developed areas is not decreased. With proper understanding and informed planning, the risk of dam- age from similar floods in the future can be greatly reduced. INTRODUCTION “It first looked like a dark heavy cloud of dust. Looked like a solid wall moving down. As it came down, every vehicle was pulled into this muck. I saw 4—6 vehicles in the debris. The wall of muck appeared to go under the lake when it hit the water, causing a swell of water at the surface.” Lemuel Washington, a weekend fisherman from Las Vegas, vividly described his impression of the onrushing flash flood of September 14, 1974, at the mouth of Eldorado Canyon. In many ways the flood Mr. Washington witnessed probably resembled a dozen or more similar floods that occurred throughout Nevada during the summer of 1974. Hundreds of these floods have occurred during historic times though many have not been observed by man. The Eldorado Canyon flood was unique because it occurred in a popular recreation area, and several accounts by witnesses have helped to document the event. Although hydrologists tend to refer to the Eldorado Canyon flood as “a spectacular hydrologic event,” Dick Mayne, Clark County Coroner, and other members of the local search-and-rescue squad call it “a catas- trophe.” Without its disastrous consequences, the flood probably would have gone generally unnoticed except by those who are interested in “spectacular hydrologic events.” Everyone agrees that the loss of life and prop- erty damage was a regrettable tragedy; however, the tragedy has triggered renewed efforts by individuals and agencies to reduce the risks involved through better planning based in part on data obtained from the El- dorado Canyon flood. These data should help those con- cerned to reach an improved understanding and knowl— edge of the forces, power, and characteristics of natural processes. Losses resulting from the flood of September 14, 1974, at Eldorado Canyon are difficult to determine accurate— ly. The complex array of physical losses and expendi— tures will ultimately be resolved; however, damages caused by the loss of life can never be accurately asses- sed or compensated. Almost all significant flood damage, with the excep- tion of highway damage along Techatticup Wash, oc- curred within the Eldorado Canyon Resort area near the canyon mouth. At least nine people lost their lives and several others may still be missing. Known dead include four men, three women, and two children. The first three bodies were recovered from floating debris at the canyon mouth during the first three days of search operations. Five other victims were recovered between 14 and 38 days after the flood. Their bodies were discov- ered floating in Lake Mohave as much as 21/2 miles north or south of the former boat landing. The restaurant was totally destroyed. Five trailer houses were totally destroyed, some have not been found, and a number of others were seriously damaged. Nine cabins near the base of the north canyon wall were destroyed, and 38 vehicles and 19 boat trailers were lost. Twenty-four boat—docking slips were obliterated and 23 boats were lost. Figure 12 shows changes to the boat 1 2 HYDROLOGY OF ELDORADO CANYON, NEV., FLOOD OF SEPTEMBER 14, 1974 docks, the general location of a number of other specific cultural features, and qualitatively describes the na- ture of the damage sustained. Several photographs of damage to structures and vehicles near the canyon mouth are shown in figure 1. Figure 16 shows an overall View of the heavily damaged trailer park area. When Viewing the damage shown in figures 1 and 16, keep in mind that the vehicles and structures receiving the greatest damage are not visible because they were either totally demolished or buried in Lake Mohave. Therefore, the photographs give a somewhat conserva- tive View of the effects of the flood. Flooding is no newcomer to Eldorado Canyon. Ample evidence of past flooding was known to local inhabitants (see section on “History”). Recent (1973) efforts by the National Park Service to revise and rearrange recrea— tional and residential facilities at the site, reportedly to alleviate flood hazards, are a matter of public record. THE SETTING Eldorado Canyon is an arid, barren, rugged 22.9—mi2 area tributary to Lake Mohave on the Colorado River. It lies in the Sonoran Desert section of the Basin and Range physiographic province as defined by Fenneman (1931). The general location of the basin and its relation to surrounding cultural features is shown in figure 2. General basin character is shown in the frontispiece. The lower end of Eldorado Canyon is also pictured in figure 5. Figure 10, another aerial photograph, shows physical characteristics of the Eldorado Canyon ter- FIGURE 1.——Flood-damaged trailer, truck, and boats. THE SETTING 13 Las Vegas I Henderson 6i 'L___._._ ‘ 4/ °>c€° a1 ‘b\\° ' '— LLI I a: i z I 4: rr-—-’ 1 : * r‘fij Lake Mead 1 r1." 4' 1 11.1 /' l_.____..__ Approximate boundary of Lake Mead Recreation Area Kingman I E 35° 114" FIGURE 2.—Location of area described in this report. minus as well as drainages to the north and south. Figure 3 shows the areal extent of the drainage basin, its topography, and the main cultural features, and delineates major tributary subareas that converge to form a single channel only a short distance above the canyon mouth. The topographic contours of figure 3 show the basin as hilly to mountainous in upstream areas. Near its mouth, the basin contains a series of east-west-alined, canyonlike, wide-bottomed arroyos incised into a mod- erately steep, eastward-sloping alluvial surface. Nelson, a village of only a few tens of permanent residents, is in the upstream, northwestern part of the drainage. Eldorado Canyon Resort, with a few perma- nent residents and a highly variable population of vis- itors, is at the downstream, eastern terminus of the basin. Eldorado Canyon Resort, within the Lake Mead Na- tional Recreation area, lies about 50 highway miles southeast of Las Vegas. Therefore, the area is a popular recreation attraction to many water sport enthusiasts, and the canyon-mouth cove provides a major boat land- HYDROLOGY OF ELDORADO CANYON, NEV., FLOOD OF SEPTEMBER 14, 1974 .mmfim 35:58 Bowfimmfim no 5583 was £233?»va mfiggymgm . mnwmmandm 553:5 BEE MESS? Emma :9?an owmgoEml .m $5on misc mmmkmzoflx m mmflz v ~ MOH \ LAKE .26. new :nmE 96% «me. E 63:24 coon fang—En Emmanaw bungee Emmm uofiwE 00:59:: .233 E mSmEZmo 20E » «gm EmeSmmmE mmEroaofi ‘ . ZO_._.mz..~:< ,mgfma as. _ $2.98.“? .52 £362 >w>3w .mEmBommv .wj E9: wmmm THE SETTING 5 ing site for Lake Mohave. Most of the facilities are on the main canyon floor, within an obvious flood plain. This subjects most residents, employees, and visitors to a high degree of risk during major floods. However, floods mainly occur during relatively short and in— frequent periods of intense rainfall and runoff; the short periods of hazard contrast sharply with generally pro— longed periods that are undeniably safe. HISTORY Eldorado Canyon was the site of some of the earliest settlements in what is now southern Nevada. It was first settled by early miners, prospectors, and mill operators in about 1861, and in 1867 Camp Eldorado was estab- lished at the canyon mouth on land now beneath the surface of Lake Mohave as an outpost of the US. Army (Casebier, 1970, p. 1 and 19). The canyon has since been the site of several mining booms and busts, accom- panied by erratic fluctuations in population. During recent times, it has been popular mainly as a recreation area. Eldorado Canyon flooding is the most important as- pect of the basin’s history related to this report. Numer- ous floods are rumored to have occurred, but almost no known hydrologic data relating to these floods have been discovered. A search of available newspaper files for information on dates and details of flooding was beyond the practical scope of this investigation. Several persons recently interviewed generally recall floods in Eldorado Canyon as follows: Mr. G. F. Gatzke, National Park Service employee, and resident of the area since 1947, recalls flooding in about 1952, 1959, 1960, 1970, and 1972 (c ral commun, September 1974). Mr. M. Em- ry, longtime resident (oral commun, September 1974), recalls reports of a very large flood in 1904 that caused heavy damage to the ore milling works at the canyon mouth, and a major flood in 1960 that heavily damaged the concessionaire’s store-restaurant he operated in the canyon mouth (a similar store—restaurant was com- pletely destroyed by the Sept. 14, 1974, flood). Photo- graphs of flood damage provided by the National Park Service (written commun, October 1974) document a flood on November 6, 1960, with evidence of severe damage and extensive sediment deposits (13,000 yd3, according to one of the photograph captions). The scanty, incomplete, possibly inaccurate, and gen— erally unverified reports listed above nonetheless categorize at least the canyon mouth area as one that has had a number of floods during the relatively short historical (about 70 years) period. A search of news— paper files would probably add more floods to those listed above. BASIN CHARACTERISTICS SLOPE The Eldorado Canyon drainage slopes generally from west to east. Quantitative data on the area-altitude distribution are summarized in table 1. Both figure 3 l and table 1 ShOW that about 70 percent of the basin’s l area is concentrated in the 2,000- to 4,000-ft altitude \ zone. TABLE 1.—Appraximate area-altitude distribution of E ldorado Canyon basin Altitude W1 7777777 #7 — r "’ -rgcentage zone Area of total (ft) (mi'z) basin area m#§T—dw 2. # TTTTTTT MW" 3,000—4,000 9.3 40.6 2,000—3,000 7.0 30.6 LOCO—2,000 3.6 15.7 647—1,000 .3 1.3 Total 22 9 “ 100.0 " Slope data were compiled from US. Geological Sur- vey 15—minute 1:62,500—scale Nelson and Mt. Perkins quadrangle maps. These data are plotted in figure 4. The figure shows that average basin slope and mean channel slopes of the three major tributaries are very similar, and are generally quite steep. The profiles show that all three tributaries have similar, generally uni- form slopes throughout their lower 4 mi of reach. This uniformity of slope also continues upstream throughout most of the length of Eagle Wash and Eldorado Canyon; Techatticup Wash is noticeably irregular in slope and profile above the lower 4-mi reach. The generally con- tinuous steep slopes, and lack of a pronounced profile concavity, are anomalous compared with most stream systems. All three tributary profiles generally adhere to a 300- to 400-ft/mi slope, or greater, throughout most of their length, including the terminal reach of Eldorado Canyon that carries their combined flow. These consist- ently steep channels, with only minimal flattening in the drainage terminus, are an efficient flushing system that produces rapid runoff. A View of overall topography including hillside slopes, minor tributaries relative to major channel slopes, and general landscape character in the lower part of the basin is shown in the frontispiece and in figure 5. GEOLOGY Geology of the drainage basin was mapped by Longwell (1963); his map, in condensed form, is also reproduced as part of the Clark County geologic map of Longwell, Pampeyan, Bowyer, and Roberts (1965). , These publications indicate that geologic units in the HYDROLOGY OF ELDORADO CANYON, NEV,, FLOOD OF SEPTEMBER 14, 1974 I I l I I I 7* I I Note: Average basin slope about lolO ft/mi, or 7.8% Drainage divide, Copper—Eldorado Canyon, Main tributary average slopes: 4:398 ft1- above mean sea 13V91 Techatticup Wash, about 370 ft/mi, or 7.0% 5000 Eldorado Canyon, about 390 ft/mi, or 7.5% - Drainage divide, Eagle Wash, Eagle Wash, about 1010 ft/mi, or 7.8% 21170“: 4.200 ft. above mean sea level Total basin relief, about 4,250 ft. Drainage divide, Techatticup Wash, \ about 3,525 ft. above mean sea level lI000 ‘ 3000 - 400 ft/mi for 6 miles — ‘:“"'/ Mouth of Eagle Wash Mouth of Techatticup Wash 2000 — W400 ft/mi for 55 miles‘ 1000 ‘ ALTITUDE, IN FEET ABOVE MEAN SEA LEVEL Topographic map lake— shore approximately 630 ft. above mean sea level l I I I I I I I I I 0 1 2 3 4 5 6 7 8 9 10 11 12 DISTANCE , IN MILES Data from 1:62,500 U.S. Geological Survey topographic maps 0 I | FIGURE 4.—L0ngitudinal profiles of main drainage channels. FIGURE 5.—Eastward aerial View of lower Eldorado Canyon. Lake Mohave in background. THE STORM 7 basin include extensive exposures of consolidated rocks in the highlands of Eldorado basin, and a much smaller area of consolidated, semiconsolidated, and unconsoli- dated alluvium in the lower part of the drainage. The consolidated rocks consist of Precambrian metamorphic and igneous rocks, some late Mesozoic and Tertiary igneous intrusive rocks, and a variety of Ter- tiary volcanic rocks. They are extensively deformed structurally, mainly by a system of north—south- trending faults. Consolidated—rock areas commonly consist of bare rock highland masses, or bedrock thinly mantled by soil or rock fragments derived from the underlying parent material. Steep slopes and lack of substantial vegetal cover render the thin soil and rock- fragment mantle very susceptible to erosion, particu— larly by intense runoff such as that which occurred during the storm of September 14, 1974. Alluvium, as mapped by Longwell (1968, pl. 1), is exposed in only the lower 2 mi of the drainage basin. Much of this alluvium is consolidated to some degree and therefore is fairly resistant to erosion. However, unconsolidated alluvium also mantles all the main stream channels and many minor stream courses throughout most of their length. A thin mantle of un- consolidated alluvium also covers many upland areas. Therefore, a large volume of alluvium is concentrated along stream channels and on interfluvial slopes throughout the drainage where it is available for trans- port, depending on surface slope, vegetal cover, gravel armoring of the deposit surface, and intensity of the runoff. VEGETATION Vegetation is generally very sparse throughout the drainage basin. Plants include cholla and barrel cactus, creosotebush, some species of yucca, an occasional mes- quite tree along arroyo floors, and other unidentified species, many of which probably belong to the atriplex genus. Greatest plant densities seem to occur in the highland areas of the basin (fig. 26), and lowest den- sities seem characteristic of the downstream areas (figs. 22—25). General views of vegetation densities in lower basin areas are shown in figure 5 and the frontispiece. The general absence or scarcity of plants throughout the basin increases the speed and eroding ability of runoff. THE STORM The flood of September 14, 1974, in Eldorado Canyon was the direct result of an intense convective thun- derstorm. A meteorological report of the storm is being prepared by the US. National Weather Service (Gerald Williams, written commun., October 1974). Therefore, this report will only briefly summarize known charac- teristics of the storm to set a stage of basic understand- ing for the following discussions of flooding and sedi— ment transport. Several characteristics of the storm had a critically important bearing on the nature of the flooding and its resultant catastrophic damage. These characteristics include: (1) time of occurrence, (2) total quantity of precipitation, (3) precipitation intensity, (4) storm track, and (5) nature of storm activity at the mouth of Eldorado Canyon during the early period of flooding. Rainfall in the upper basin apparently began some- time around 1:00 p.m. (G. F. Gatzke, oral commun., September 1974), and the most intense rainfall at Nel- son was around 1:45—2:00 p.m. (Thomas Jester, Nelson resident, oral commun., September 1974). Jester recal- led a total storm duration of about 11/2 hours at Nelson, which generally agrees with observations of A. R. Methvan, another Nelson resident. Methvan recorded 1.9 in. of total storm precipitation (oral commun., Sep- tember 1974). According to Jester, storm clouds came into the Nelson area from the south. TL" clouds then apparently swung around near the north in. its of the drainage divide when precipitation began, and sub- sequently passed over Nelson moving in a southeast- ward (downstream) direction during the period of in- tense precipitation. Several other observers also noted the general downbasin movement of the storm center. Both Jester and Methvan estimated the period of greatest precipitation intensity as less than half an hour. Eyewitness accounts near the canyon mouth indi- cate that greatest precipitation intensity spanned a quarter to half an hour. Several excerpts from a preliminary draft of the US. National Weather Service report (Gerald Williams, written commun., October 1974) further characterize the storm as follows: This flash flood was caused by record-breaking rainfall from an isolated thunderstorm cell that moved slowly down the drainage channel in a way that maximized flooding. * * * Duration of rainfall was short, generally less than one hour. Intensities were very high-— at least three inches per hour and as high as six inches per hour for 1/2 hour. The storm appears to have moved downstream at the rate of about 5 to 10 miles per hour, coinciding with the movement of surface runoff. Highest rainfall intensities and quantities appar- ently occurred in middle to lower parts of the basin, rather than at the higher altitudes. On the basis of experience with other recent flash floods in Nevada, this characteristic is not uncommon, and may be more nor- mal than abnormal. If true, hazard zoning for flooding probably should not relate flood potential strictly to altitude or differences in altitude, in the generally ac- cepted “orographic influence” philosophy. Eyewitness accounts describing the arrival of the very destructive leading edge of the flood front all de- scribe it as being accompanied by intense rainfall, 8 thunder, and hail at the canyon mouth. The time of intense destructive flooding and precipitation at the canyon mouth is placed by most eyewitness accounts at about 2:30 pm. Therefore, four storm characteristics were critical to flooding and damage. The storm and flooding occurred during the early afternoon on a Saturday, presumably at a time of moderate use and occupancy at the canyon mouth. The high precipitation intensity, combined with the basinwide nature of the storm, yielded large quan- tities of rainfall during a short period and maximized the flooding. The downstream pattern of storm move— ment caused intense rainfall and runoff to be superim— posed on downstream flood waves, compounding the peak intensity of surface runoff. Finally, the intense rainfall and hail at the canyon mouth probably caused people to run for or remain under shelter rather than leave the canyon floor. RUNOFF FLOW RATES Peak flow rates are important to the process of under- standing the hydrology of flash flooding, and to help categorize different flash floods according to magnitude and intensity. At Eldorado Canyon, the major damage to lives and property was caused by the leading edge of the flood runoff. Peak flow apparently followed, rather than coincided with, the initial surge of the flood. There- fore, peak flow estimates probably do not bear directly on damage and casualties. This is not always the case in general flooding or even in flash flooding, Where peak flow can be a more important factor with regard to human losses. Peak flow rates are also important when establishing design criteria to cope with future floods. Peak flow rate is one of the few hydraulic parameters which generally can be computed or estimated with reasonable accuracy after the flood has passed. There- fore, we attempted to assess peak flow rates at Eldorado Canyon. The peak discharge was computed for the main chan- HYDROLOGY OF ELDORADO CANYON, NEV., FLOOD OF SEPTEMBER 14, 1974 nel just above the trailer parking area (fig. 15 and table 2), using the standard US. Geological Survey indirect slope-area method (Dalrymple and Benson, 1967). This technique generally gives reasonable results when pre- vailing flow conditions are within the limitations for which the technique applies. Flow conditions in El- dorado Canyon may not have been ideal for proper ap- plication of the slope-area method; therefore, the peak ‘ flow computed may be considerably in error. Some fac- tors that may have caused serious errors in the meas- ’urement include: (1) unsteady flow, (2) abnormally high sediment concentrations, causing high fluid viscos~ ity, and (3) a cross-sectional flow area, at the time high—water lines were deposited, that differed from the area determined later at the time of the indirect meas- urement. These factors are generally influential to var- ying degrees in peak-flow measurements of most, or all, flash floods in the desert southwest. Nonetheless, the t slope—area method is the best available technique. 4 The slope-area method was applied to a situation where steady-state flow may not have been dominant, 1 however, because the state of flow was unknown, a “ steady-state condition was assumed. Very high sedi- ment concentrations were apparently associated with the initial flood surge (see section titled "Sediment Transport Characteristics”), but concentrations were probably much lower during later peak flows. In any ’ event, high water lines, which provide the key basic data for slope-area determinations, were obviously created by flow much more dilute than a viscous 1 mudflow. ’ After considering the factors discussed above, the 76,000 ft3/s computed is the best estimate available at present. The peak discharge plots close to a curve de- veloped by Matthai (1969) for maximum discharges in relation to drainage areas in the United States (fig. 6). There are at least two indications the estimate may be too high. (1) The mean velocities calculated for the two downstream cross sections of the slope-area measure- ment were 34 and 39 ft/s. These exceed the known mean TABLE 2.—Summary of hydraulic data resulting from peak-flow estimates Estimated Measured Estimated Approximate Estimated Determination type peak cross-sectional mean tributary unit and “mm $6375“ $133? viii/6;? 3535) («537573in Slope-area method Eldorado Canyon below Eagle and 3,030 25 Techatticup Washes 76,000 (2) 2,230 (2) 34 22.8 3,300 1,920 39 Slope-conveyance method Eldorado Canyon above confluence with Eagle and Techatticup Washes 24,000 1,010 24 13.0 1,800 Eagle Wash near mouth 25,000 807 31 4.5 5,600 Techatticup Wash near mouth 11,000 421 26 3.2 3,400 1Measurement sites shown in figure 3. 2Values for individual cross sections. RUNOFF 1000 I IIIIIIll | IIIIIIII | Adapted from Matthai (1969, p. 86) 100 Eldorado Canyon CUBIC FEET ‘PER SECOND Adapted from Hoyt and Langbein (1955, p. 60) PEAK DISCHARGE, IN THOUSANDS OF 1 lllIIIIII I IIIIIIIl I 1 10 100 DRAINAGE AREA, IN SQUARE MILES l | I 1000 ' FIGURE 6.——Maximum water discharges in relation to drainage areas in the United States. velocities, and most point velocities in natural channels except for some flood waves after dam failures. (2) At the time high water lines were created, an unknown quan— tity of sediment was passing through the slope-area reach as bedload. This bedload covered the channel floor to some unknown depth and thereby reduced the cross- sectional area if minimal channel scour is assumed to have prevailed at that time. The possible error in cross- sectional area would thereby have caused an indeter— minate error in the peak flow estimate. ’ Field estimates were made of peak flow rates in the lower reaches of the three major tributaries, above the slope-area site, using the slope-conveyance technique. This technique is less accurate than the slope-area method. Results of these estimates are also shown in table 2. If the slope-conveyance estimates are added together, and their sum is adjusted for assumed flow pickup between these measurement sites and the slope-area site, a peak flow estimate of 70,000 to 80,000 ft3/s is indicated. This mathematical approach is jus- tified only if the peak flows of the tributaries contrib- uted to the main trunk system with the proper timing to allow direct summation. Such a situation would nor- mallybe unlikely; however, the nature of this storm, with its downstream movement and the apparent oc- currence of greatest rainfall intensities in the lower parts of the drainage basin, tend to favor a cumulative effect from the tributary peaks. Flow velocity can be estimated in the canyon constric- tion above the site of the destroyed restaurant (fig. 12), if the estimated 76,000-ft3/s peak flow is assumed to have 9 occurred at that location. The high-water profile and preflood topographic map suggest an average flow depth of about 20 ft within this cross section. For this depth, the cross—sectional flow area would have been about 1,800 ft2. The resultant mean velocity would have been about 42 ft/s, similar to velocities in the slope-area reach (table 2). The flow rate and velocity of the damaging initial flood surge at Eldorado Canyon cannot be determined because later flow apparently erased high water lines of the initial surge. The character and effects of the initial surge are discussed in greater detail in following sec— tions. FLOOD WAVE CHARACTERISTICS Specific details of the flood waves are of special in- terest because they caused most of the property damage and apparently were instrumental in most of the deaths. Dramatic descriptions by eyewitnesses of the arrival of the initial flood wave are included in the section entitled “Sediment Transport Characteristics.” However, the intensity of local runoff near the canyon mouth was apparently impressive prior to the arrival of the first damaging flood pulse. Eyewitness John Galli— fent observed heavy runoff from his south-facing trailer window. The trailer was parked along the north canyon wall in the area just downstream from the point where the highway access road descends to the canyon floor (fig. 12). Gallifent became alarmed when he noted ab- normally large flows of water pouring into the canyon from numerous rills and small gullies along the south canyon wall. He concluded that such heavy flows from minor tributaries of minimal drainage area foretold even greater runoff from upstream. He had just enough time to escape afoot to higher ground. Lemuel Washington also observed local runoff on the canyon floor near the canyon mouth prior to arrival of the initial flood surge. He characterized it as “a good stream * * * like a small river.” Mrs. Kirby L. Koop described the local runoff along the canyon floor as knee— to thigh- deep before the first major wave arrived. Kirby L. Koop watched the approach of the initial flood surge from near the icehouse area (fig. 12). He first saw it at a distance of about 100 yd. He recalled the dull thuds of cars caught up in the surge striking the canyon walls. According to Koop, when the mass of debris and water arrived at the preflood shoreline of Lake Mohave, it possessed such momentum that it appeared to "hy- droplane” over the lake surface as far as the boat dock gangway (a distance of 100 to 150 ft, scaled from fig. 12). The mass then seemed to fall vertically into the lake. Lemuel Washington’s recollection is somewhat dif- ferent. His statement to the National Park Service says, "* * * the wall of muck appeared to go under when it hit the water, causing a swell of water at the surface. ThenI 10 saw boats floating, bouncing, cracking, and saw a sta- tion wagon come to the surface and go back again.” Both Washington and Koop described great turbu- lence as the flood flow entered the lake. Washington mentioned "* * * the up-surge* * * coming back in full of debris.” Koop’s statement to the National Park Service described a truck in the flood flow ramming and break— ing the boat dock. He said that the flood-surge turbu- lence then “* * * started to suck or pull the rest of the dock, boats, and all back into the oncoming water.” Koop continued, “* * * a trailer * * * hit the lake, it was ground up. There were two boats trying to get out, one boat with four persons and one boat with one man in it. The force of the water pulled these boats back into the shore, pulled them stern first down and ground them up.” Both accounts suggest a powerful destructive un- dertow near the lakeshore. The mouth of Eldorado Canyon during the flood is shown in figure 7A, as photographed by Kenneth E. Beales of Las Vegas, N ev., during late stages of the flood recession. The same general view, about 2 weeks later, during excavation and cleanup of flood sediment de— posits (fig. 7B), provides perspective on the approximate depth of flow at the time of Beales’ photograph. J. P. Monis and P. A. Glancy, US. Geological Survey, reconnoitered the east shore of Lake Mohave on Sep- tember 19, 1974, for evidence of wave action caused by the flood surges entering the lake. Figure 8 shows the best noted evidence of possible flood wave action, at the base of a large sand dune across Lake Mohave about half a mile east and slightly south of the Eldorado Canyon mouth. The dune and its location relative to Eldorado Canyon are shown in the upper right part of figure 15. The horizontal cut in the sand above the flood debris (fig. 8), that was deposited before the lake was purposely drawn down to aid search-and-rescue operations, suggests a maximum wave height of about 1% ft. How- ever, the horizontal cut may have originated from a higher preflood lake stand. In any event, no known evidence was observed of flood wave action greater than about 1% ft. Apparent response of the stage of Lake Mohave at Davis Dam, about 35 mi downstream from Eldorado Canyon (fig. 2), to the flood wave is shown in figure 9. The figure indicates that lake stage rose approximately 0.45 ft shortly after 2:30 pm. the day of the flood. RUNOF F VOLUME Total storm runoff into Lake Mohave was roughly estimated by the US. Bureau of Reclamation as about 2,000 acre-ft (G. B. Freeny, oral commun., 1974). This estimate was made on the basis of apparent change in contents of Lake Mohave caused by inflow and direct precipitation on the lake, and adjusted by preflood and HYDROLOGY OF ELDORADO CANYON, NEV., FLOOD OF SEPTEMBER 14, 1974 postflood reservoir release trends. Aerial reconnais- sance of the general area adjacent to Eldorado Canyon basin affirmed that the major share of inflow to Lake Mohave probably came from Eldorado Canyon. The generally undisturbed character of channel-bottom vegetation shown in figure 10 supports the conclusion that there was no heavy runoff in areas adjacent to Eldorado Canyon. Therefore, the flow to the lake from Eldorado Canyon itself was estimated at about 2,000 acre-ft. Figure 11 shows an estimated hydrograph of runoff to the lake from Eldorado Canyon. This hydro- graph was constructed from the following data: (1) known zero flow before and after the flood, (2) an esti- mated peak flow rate of about 76,000 ft3/s, (3) an esti- mated total duration of flow as described by eyewitnes- ses, and (4) the general shape of hydrographs for re- corded flash floods in the same general hydrologic area. Runoff volume as determined from the hydrograph is also about 2,000 acre-ft. MEASURED STREAMBED AND HIGH-WATER PROFILES Figures 12, 13, and 14 show locations of flood bound- aries, high-water profiles, streambed profiles, and a qualitative assessment of damage to some cultural fea- tures in Eldorado Canyon. Figure 15 shows the general flood plain extent and characteristics just above the developed area. The average slope of the profiles in the measured reach (fig. 12) is 280 ft/mi. The left-bank profile through the trailer park area indicates a 2- to 4-ft depth of water above the canyon floor (figs. 14 and 16), whereas the right-bank profile in the same section is defined by one piece of debris found on the vertical wall about 16 ft above the canyon floor. Assuming that this piece of debris actually represents the true water sur- face along the right bank, the difference in left- and right-bank elevations must be explained by the sloshing of water from bank to bank (figs. 12, 7A), and by local pileup of water caused by cars and boat trailers in the parking area. Downstream from the trailer parking area (fig. 14), the left- and right-bank profiles become very erratic and indicate water pileup due to the con- traction of the reach. The momentum of the flowing water forced the water up and over the projecting bed- rock ridges. The profiles (fig. 14) show that the water surface along the left bank was as much as about 25 ft above the canyon floor where the flow was pushed up and over the projecting rock ridge. Figure 16 shows the contrast between trailers caught within the left-bank high water line (damaged) and those on slightly higher ground (undamaged). FLOOD FREQUENCY AND MAGNITUDE N o accurate definition of the recurrence interval for a flood peak of 76,000 ft3/s in Eldorado Canyon is possible RUNOFF 1 1 9’74, probably during the late recession of flooding (photograph by Kenneth ). B, On October 1 during excavation of flood sediment deposits. FIGURE 7.—Mouth of Eldorado Canyon. A, On September 14, 1 E. Beales, Las Vegas, Nevada 12 because of insufficient data. However, empirical methods being developed from data throughout south- ern Nevada (D. 0. Moore, oral commun., 1974, and Moore, 1974) were used to estimate 10- and 25-year flood magnitudes for Eldorado Canyon near the canyon mouth. The peak flow estimates for the 10- and 25-year flood are 80 and 200 ft3/s, respectively. The 8O-ft3/s flood, assuming an asphalt channel bottom through the trailer parking area (fig. 16) with the surface configura- tion as surveyed on September 16, 1974 (approximate profile stationing 1400, fig. 12), would be about 0.5 ft deep with an approximate mean velocity of 6 ft/s. The 200-ft3/s flood would be about 0.75 ft deep with an ap- proximate mean velocity of 8 ft/s. The scanty data and estimates described above suggest that a flood magnitude of 76,000 ft3/s would apparently have a large but unknown recurrence inter- val. However, it should be emphasized that flood mag- nitude and frequency are founded on the theory of prob- ability. This introduces a risk factor. Also, long term data for floods in ephemeral stream channels in Nevada are very scarce. Therefore, a frequency analysis of maj or floods is based on little factual experience. The magnitude of the September 14 flood gives no guarantee that another disastrous flood will not occur in the foreseeable future. Therefore, a reasonable course would be to assume such a flood can and'may occur in any given year. SIMILAR FLOODS Areas in southern Nevada and nearby States known to have been subjected to high-intensity thunderstorms FIGURE 8.—Wave-cut bench (above debris line) along east shore of Lake Mohave, possibly caused by flood surges entering the lake. HYDROLOGY OF ELDORADO CANYON, NEV., FLOOD OF SEPTEMBER 14, 1974 K“ SEPTEMBER 14 fl. 633 632 L 1 I . O 12 24 TIME, IN HOURS LAKE STAGE, IN FEET ABOVE MEAN SEA LEVEL FIGURE 9.—Trace of Lake Mohave stage at Davis Dam, showing ap- proximately 0.45-ft rise. Gage is about 35 mi downstream from mouth of Eldorado Canyon. Figure is reproduction of lake stage recorder sheet. similar to that which struck Eldorado Canyon include the following: 1. An unnamed stream in the McCullough Range near Searchlight, Nev., in late August 1971. 2. Bullhead City, Ariz., area in late summer 1971. 3. Red Rock Wash near Las Vegas, N ev., on January 27, 1969, and July 23, 1974. The McCullough Range between Henderson and Railroad Pass, Nev., in 1969 or 1970. 5. Grapevine Canyon in Death Valley, Calif, on Au- gust 14, 1968. Black Canyon near Wickenburg, Ariz., on Sep- tember 14, 1964. 7. Picacho Wash near Imperial Dam, Calif., on Sep- tember 14, 1974. Table 3 summarizes data for some floods in the west- ern United States with peak flow rates per unit drain- age area greater than that of Eldorado Canyon on Sep- tember 14, 1974. TABLE 3.—Floods having peak flows per unit drainage area greater than that of Eldorado Canyon Drainage Peak Unit Location areas discharge runoff (mi?) (ft3/s) [m3 )/mi2] Bronco Creek near Wikieu , Ariz. 20 73,500 3,700 Meyers Creek near Mitchell, Ore. 127 54,500 4,300 Trujillo Arroyo near Hillsboro, N. Mex. 6.9 45,000 6,500 South Fork Pine Canyon Creek near Waterville, Wash. 54 25,000 4,600 Little Pinto Creek tributary near Newcastle, Utah .30 2,630 8,800 Lahontan Reservoir tributary No. 3 near Silver Springs, Nev. .22 1,680 7,600 Eldorado Canyon, Nev. 22.8 76,000 3,300 I .mhgiwwm .8 ~86ng om Enfimuawm no mwmmfigw 9:83?» «Em mwmfigv £2980 ovmaogmmo sum? 3:823 mg .«o Beam 3in 185.6 >\I.OH "35lo h «@962 no $3.38 amaumouosm .vbma T N E m D E S 14 HYDROLOGY OF ELDORADO CANYON, SEDIMEN T SEDIMENT DEPOSITS Fluvial sediment transport was an important aspect of the September 14 flood. The greatest immediate im- pact of sediment deposition was the practical problem it posed for search-and-rescue crews. Sediment deposits at the canyon mouth and in Lake Mohave blanketed sev- eral acres to thicknesses of up to 12 ft. Much of this sediment had to be removed during the search for vic- tims and missing property. Also, excavation of the material prolonged and increased lake turbidity near the landing and thereby hampered underwater search by divers. The cost of removing sediment deposits was great, and probably accounted for the major part of the search-and-rescue expense. The sediment volume accounted f0 is estimated to be 54,000 yd3. location and distribution of th posits; location of the depositi figure 17. The estimate was in flood configuration of deposits pographic information. Estim from the preflood shoreline o are reasonably accurate beca ographic data were available. However, no recent preflood bathymetric data were available for the harbor or adjacent areas. Some general knowledge of preflood water depths is available from observations by the N a- tional Park Service staff and others. These sparse data are supplemented with estimates of the quantity of material actually excavated and removed, as well as evidence of depths to apparent preflood lake-bottom clays exposed during excavation. The 54,000-yd3 estimate does not account for an un- known silt-clay fraction of the total sediment load. This r in known deposits Table 4 describes the e known sediment de- onal units is shown in ade on the basis of post- and on some preflood to- ates of deposits upstream f Lake Mohave probably use detailed preflood top- TABLE 4.—Estimated nono [Data regarding areal distribution and estimated thickness of deposits mainly provided by T. 1974). All quantities rounded because of nature of esti NEV., FLOOD OF SEPTEMBER 14, 1974 part of the load was probably dispersed widely through- out Lake Mohave because of its small particle size and inherent slowness of settling. Therefore, the 54,000-yd3 deposit probably represents a lower limit of total sedi- ment load. A reconnaissance characterization of the sediment deposit according to particle-size distribution was at- tempted (extensive sampling and analysis was beyond the scope of the study). Six samples of excavated mate- rial were arbitrarily collected on September 30, 1974, when the large mass of available excavated material probably was representative of most of the recoverable sediment. Samples were collected by P. A. Glancy (US. Geological Survey), and standard sieve analyses were made by the Materials Testing Laboratory, Nevada State Highway Department, Las Vegas. Results of the sieve analyses are listed in table 5, and figure 18 pic- tures the material sampled at each site. Samples were collected from piles of excavated sediment dumped up— stream from the trailer park area. The piles are clearly visible upstream from the access highway in the aerial photograph of September 20 (fig. 10). Samples were carefully collected to typify the mass of material exca- vated, and are believed to be generally representative of that mass, within limitations imposed by the small number of samples that could be collected feasibly. On the basis of analytical results in table 5, the sedi- ment excavated from the deposits can be characterized as follows: less than 1 percent boulders, about 60 to 80 percent gravel, about 10 to 30 percent sand, and less than 3 percent silt and clay. As described above, the silt-clay fraction of the sampled deposits probably is less than that contained in the total sediment load of the flood. Seven additional samples were collected from drain- age slopes and channel bottoms of Techatticup and rganic sediment deposits R. Gess, National Park Service Engineer (oral and written commun., September and October mates] . E t' t d t' Map zone Approximate Estimated Estimated S $111: e (E; léligi Location of deposits shown in area average volume weight of Of- figure 17 (acres) thickness (yd3) de osits sediment (m < WM) 3 (tons) Upstream end of park development b 130 to upstream edge of boat landing 1 2.6 3 13,000 b Upstream edge of boat landing 130 60,000 to preflood shoreline 2 .6 4.5 4,700 b Preflood shoreline to postflood 130 shoreline 3 1.1 9 16,000 Below postflood lake surface 4 2.3 5.5 20,000 c 100 27,000 Subtotal 6.6 54,000 87,000 Somewhere in Lake Mohave beyond ' limits of known deposits Not shown unknown unknown d16,000 880 17,000 Total (rounded) >6.6 70,000 100,000 gUnit weight estimates were adopted from data of Hough (1957, p. 30—31). ainly moderately compacted gravel, sand, and small amounts of boulders and fines. CLoosely compacted sand with small amounts of gravel and fines. d Difference between generally known deposi e Probably very loosel crude estimate of total load transported (70,000 yd3) and estimate of ts (54,000 yda). y compacted silt and clay with some fine sand and very small amounts of medium sand. in SEDIME NT 1 5 80 ,000 I I I I I I 70,000 — — 60,000 " — 50,000 " — 40,000 — - 30,000 — - DISCHARGE, IN CUBIC FEET PER SECOND 20,000 — — 10,000 " — 0 l | I l 0 1 2 3 4 5 FLOW DURATION, IN HOURS FIGURE 11.—Estimated flood hydrograph for September 14, 1974, near mouth of Eldorado Canyon. Eagle Washes and Eldorado Canyon, 2 to 4 mi upstream. from Lake Mohave, in an attempt to characterize particle-size distribution of sediment subjected to ero- sion. These samples all exhibited generally similar grain—size distribution, averaging about 50 to 70 per- cent gravel, 25 to 40 percent sand, and 4 to 8 percent silt-clay. However, because they represent postflood conditions and are not a statistically significant sam- pling of the overall drainage basin, they may not accu- TABLE 5,—Approximate particle-size distribution of sediment samples Approx- Percent passing seive, by weight . imate US, , Size size of standard ‘ Sample number class opening Sieve (mmJ E01 EC—2 EC—3 EC—4 E05 EC—G Small cobbles 100 4 in ,,,, 100 _-,_ 1", 100 .1" (>64 mm) 75 3 in 1,1, 83 “A. 100 97 A” 50 2 in 100 79 100 96 72 11,, 37.5 1V2 in 95 75 99 92 64 100 Gravel 25 1 in 89 65 95 82 55 97 (2434 mm) 19 34 in 81 58 91 73 46 91 125 V2 in 71 49 82 59 38 80 9.5 3/5 in 63 43 73 51 32 72 4.75 No. 4 48 31 53 35 21 50 2.00 No, 10 28 18 33 20 12 27 S nd 1 18 N0. 16 18 12 23 15 9 17 a“) 0624 0.425 No. 40 7 4 12 s 5 6 ' "1"” 0.300 No. 50 6 3 11 7 4 5 0.150 No. 100 3 2 8 5 3 3 Silt—clay (<0.062 mm) 0.075 No, 200 3 l 6 4 3 2 rately represent sediment eroded, transported, and de- posited by the flood. As with the flood deposits sampled, the silt-clay component of the upstream material may be underrepresented. However, the silt-clay fraction might be assumed to have made up less than one-fourth the total load, be- cause sand was considerably less prevalent than gravel in the material recovered. Therefore, the total sediment load transported by the flood is roughly estimated at 70,000 yd3 (purposely rounded to one significant figure) which allows a crude, but necessary, adjustment for the otherwise unaccounted fine—grained load component. Table 4 shows data for all known and assumed sediment deposits, except those for floating debris. The table also includes estimates of sediment weight for individual deposits. Total weight of all generally nonorganic sedi— ment is estimated about 100,000 tons. Particle-size distribution, by weight, of the estimated sediment load (less organics) can be roughly approxi- mated from the data of table 4, using some arbitrary assumptions, as follows: boulders, less than 1 percent; gravel, about 40 percent to 60 percent; sand, about 20 percent to 40 percent; and silt-clay, about 10 to 25 per- cent. Large boulders, common constituents of many inten- sive floods in the southwestern United States, were gen- erally absent in the September 14 flood deposits. An occasional boulder was noted during excavation or ob- served in piles of excavated material. Selected examples of the measured triaxial diameters, in feet, of these observed boulders are as follows: 3 X 1.5 x 1.2; 3 X 1.5 X 1; 2.8x 1.3x 1.5; 2x1.5><0.5; 1.8><1.1><1><0.8. Another large boulder unearthed in the deltaic material (5.4x3.7><3.2 ft) may well have been deposited by some previous runoff event. Figure 17 shows the approximate area of new land surface created in the harbor as a result of sediment deposition. New land surface was delineated on the basis of the prefiood topography shown in the figure and 16 HYDROLOGY OF ELDORADO CANYON, NEV., FLOOD OF SEPTEMBER 14, 1974 postflood (Sept. 18 and 20, 1974) aerial photographs supplied by R. J. Gregory, Director, Nevada Civil De- fense and Disaster Agency, and the Nevada Highway Department (fig. 10). Land surface was increased by about 1.1 acres, and the harbor shoreline was extended lakeward about 350 ft. The in—place character of sediment deposits at the canyon mouth was only rarely disclosed during excava- tion because most steep slopes created by digging slumped almost immediately. Figure 19 pictures a rare near-vertical exposure of upper beds of material de- posited along the right canyon wall near the shoreline of Lake Mohave. The photograph shows stratified sand and gravel probably deposited during the runoff reces— sion. Floating debris, mostly manmade artifacts and up- rooted vegetation, temporarily covered a large area of harbor surface adjacent to the newly extended land sur- face. The extent of this debris is generally shown by figures 17 and 20. Most floating debris was restricted to about 1.1 acres of water-surface area by the afternoon of September 15 (fig. 20). A very rough estimate of floating debris is about 4 acre-ft, using the area shown in figures 17 and 20 and assuming an average 3 to 4 ft thickness of deposits (T. R. Gess, oral commun., 1974). Removal of the floating debris (fig. 20) required about a week’s labor, but the efforts yielded the bodies of three flood victims (fig. 17). The pulverized debris and the nude bodies testify to the tremendous energy expended by the flood in the terminal reaches of Eldorado Canyon. SEDIMENT TRANSPORT CHARACTERISTICS The scarcity of boulders in deposits from the Sep- tember 14 flood seems anomalous when field examina- , tion of upstream areas shows a large number of boulders on many hillslopes and in numerous small tributary channels. However, field reconnaissance shows that the boulders are characteristically scarce in the postflood ‘w. . a ‘\ B‘T TQRAG AREA ‘ & Base map furnished by the National Park Service FIGURE 12,—Flood boundaries, streambed HEAVILY DAMAGED TRAILER- PARKING AND CABIN AREA m1 SEDIMENT surface deposits of Eldorado Canyon and Eagle Wash, but Techatticup Wash contains a greater number of boulders scattered along its main channel. It is assumed preflood channel deposits were similar in particle-size distribution. Therefore, boulders observed on hillslopes and in small channels presumably were not subjected to streamflow intense enough, on or recently prior to Sep- tember 14, to move them to the main channels where velocities on September 14 probably would have been adequate to have transported many of them long dis- tances. As a result, the flows that collected in the three main drainage channels (Eagle and Techatticup Washes and Eldorado Canyon) transported only the available material, which was apparently dominated by gravel. Evidence of at least some large—boulder movement in Techatticup Wash is suggested in figure 21. The boul- ders shown mantling the channel floor are in the ex- treme west center of sec. 5, T. 26 S., R. 35 E., just 17 upstream from the waterfall of'Techatticup Wash. They lie in a locally wide section of the wash, suggesting that they were deposited because of rapidly decreasing flow velocities associated witn the channel expansion. Most of them were probably in motion during the September 14 flood. An exceptionally large boulder that may well have moved some distance during the flood is shown in figure 22; its dimensions are 6X4X2.5 ft. Figure 24 shows a boulder lodged under the front bumper of a car aban- doned during the flood in the lower reaches of Eagle Wash. The boulder (dimensions 2X 1.5x 1 ft), overlying a live bush, obviously moved during the flood. The rough estimate (70,000 yd3) of the total nonor- ganic sediment deposited at or near the mouth of El- dorado Canyon, plus the estimate of inflow to Lake Mohave from Eldorado Canyon, allow reasonable specu- lation on additional sediment-transport characteristics of the September 14 flood. The estimated dry weight of UNDAMAGED TRAILER—PARKING AREA ESTIMATES DISCUSSED IN TEXT RESTAURANT (DESTROYED) figfik ' mm CONCESSIONAIRE'S HOME fl 0 200 400 (UNDAMAGED) I_.—__L——__—_l Profile stationing, in feet ICEHOUSE AREA (MODERATELY DAMAGED) Outer limits of flood through profile section Note: rrofiles shown, at different scales, in fig— ures 13 and 14. Slope area site between stations 86 and 642. 200 400 690 800 FEET | I I 50 100 O—-O l l 150 200 METRES LOCATION OF VELOCITY AND CROSS-SECTIONAL PREFLOOD BOAT-DOCK LOCATION (DESTROYED 0R DISPLACED) LAKE MOHA VE profile line, and specific cultural features. 18 sediment deposits is shown to be about 100,000 tons in table 4. Sediment deposits below the postflood lake sur- face are equivalent to about 12 acre-ft of solid rock on the basis of estimated volume and unit weight of the deposits. Pure water inflow, dismissing organic debris, was about 1,988 acre-ft (2,000 acre-ft total inflow minus 12 acre-ft of rock) or about 2,700,000 tons. Therefore, the overall water-sediment mixture delivered to the terminal reaches of Eldorado Canyon was water- dominated (about 31/2 percent sediment, by weight). The mean sediment concentration for the total water- sediment mixture, not counting organics, may have been about 36,000 mg/l (milligrams per litre). Recogniz- ing limitations on estimates of total streamflow and sediment, as well as unknown weight of organics, a mean total-sediment concentration of 30,000 to 40,000 mg/l seems reasonable. This statistic also indicates that sediment transport during the flood was important, but the material delivered to the canyon terminus was nonetheless a water-dominated mixture. The water- HYDROLOGY OF ELDORADO CANYON, NEV., FLOOD OF SEPTEMBER 14, 1974 sediment composition probably varied greatly with time and location, and probably was rarely equal to the mean concentration. Several persons witnessed the flood flows in the vicin- ity of the boat landing at the canyon mouth. Lemuel Washington of Las Vegas, Nev., and Kirby L. Koop of Placentia, Calif, both describe the initial flood surge as being very heavily laden with sediment having a consis- tency generally equivalent to freshly mixed concrete (Washington) and not quite as viscous as freshly mixed concrete (Koop). Both witnesses describe the initial flow definitely as a vertical wall of water mixed with sedi— ment and manmade artifacts. Unfortunately, both wit- nesses were observing the oncoming flood along a line of sight parallel to the direction of movement, which is a disadvantageous position from which to accurately judge whether the leading edge was near-vertical. It is certain, however, that the mixture arrived as a sudden onrush of streamflow carrying a very high concentra- tion of sediment; that it had picked up a conspicuous ; E 8 IO 0 O I l I ELEVATION, IN FEET ABOVE MEAN SEA LEVEL 3‘ o l PROFILE STATIONING, IN FEET HIGH-WATER LINE -\. ( STREAMBED 800 — 780 — 740 — ELEVATION, IN FEET ABOVE MEAN SEA LEVEL Note: different scale in figure 12 Map view of profile locations shown at 600 R I G H T B A N K ‘ . HIGH-WATER LINE '\.\‘ . ' \'\. \\". _ \. f S TREAMBED FIGURE 13.—Profiles of peak discharge high water lines and streambed at slope-area site in Eldorado Canyon. SEDIMENT array of manmade artifacts from the upstream parking lots, trailer village, and campground facilities, and that it probably contained an appreciable amount of up- rooted vegetation. Koop further describes the leading edge of the onrushing mixture as raining or spraying out gravel as large as several inches in diameter. He characterized the flow as dark brown in color, but indi- cated that the oncoming flow was not audible. Mrs. Koop, also an eyewitness with her husband, described the initial flow as so abrupt that at first she thought a dam must have burst somewhere upstream. Mr. Koop’s impression of the oncoming mass of material was de— scribed in a statement to National Park Service person- nel, as follows: When I got around the small nose which was behind the block-ice machine and started walking toward the coffee shop, I looked up for a second. I became disoriented because I thought the mountain had moved. Then I realized what we were seeing was a wall of water about 20—25 feet high stacked with cars, trailers, etc., smash into the coffee shop, post office, and they exploded like there was dynamite inside. Figure 23 shows the location of high water lines just upstream from the coffee shop site, where the canyon narrows abruptly. Flow depths at this point, approxi- mately where the oncoming surge of water was observed 19 by Koop, generally support his estimate of surge height. Lemuel Washington, in his statement to the National Park Service, described the approaching streamflow as follows: “It first looked like a dark heavy cloud of dust. Looked like a solid wall moving down. As it came down, every vehicle was pulled into this muck. I saw 4 to 6 vehicles in the debris. The wall of muck appeared to go under the lake when it hit the water, causing a swell of water at the surface.” Washington indicated that he first sighted the approaching flow when it was above the trailer court; at that point, it appeared as an approach- ing wall about 6 t0 8 ft high. Koop apparently first observed the surge as it was entering, or had just en- tered, the canyon narrows immediately upstream from the coffee shop (restaurant). The fOregoing accounts strongly imply that sediment concentration of the initial flood surge was considerably higher than the estimated mean concentration of 30,000—40,000 mg/l. The statements generally charac- terize the onrush as a highly charged debris flow that may have had the general consistency of a mudflow. Koop (oral commun., 1974) described the initial “wave” as being followed by several wavelike surges, none of 740 - 720 ~— 700 — TRAILER HOMES ROAD ENTERING ELDORADO CANYON PROPER—>— ELEVATION, IN FEET ABOVE MEAN SEA LEVEL 660 — 1200 I I I I l x 1400 1 e I VERTICAL CLIFF 1600 l l \ kDEBRIS ON VERTICAL WALL 720 '— 700 - L _J‘ 680 — APPROXIMATE AREA OF CAR AND BOAT TRAILER PARKING ELEVATION, IN FEET ABOVE MEAN SEA LEVEL 660 - PROFILE STATIONING, IN FEET ‘ (HIGH-WATER MARKS IMPOSSIBLE T0 LOCATE) } WATER PILEUF CAUSED BY CONTRACTING CHANNEL, FLOW OVER PROJECTING BED— ROCK LEDGES, AND DIRECTION OF FLOW l LEFT BANK l APPROXIMATE RESTAURANT LOCATION 1300 2000 i l i I I I RIGNT BANK AREA or I{’_O0NCESSIONAIRE'S HOME ‘\§ tSTREAMEED FIGURE 14.—Profiles of peak discharge high water lines and streambed, Eldorado Canyon Resort. 20 HYDROLOGY OF ELDORADO CANYON, NEV., FLOOD OF SEPTEMBER 14, 1974 FIGURE 15.4Downstream (eastward) aerial photograph of Eldorado Canyon terminus taken September 17, 1974. Boat storage area to right. Horizontal lines show approximate slope-area site. FIGURE 16.—Heavi1y damaged trailer park at Eldorado Canyon Re— sort. Afternoon, September 19, 1974. which he observed to noticeably recede before a sub- sequent surge further increased the flow depth. If cor— rect, Koop’s description may explain why no mudline marked passage of the initial surge. Neither the Koops nor Mr. Washington observed any movement of large boulders during the flood. The foregoing description of sediment transport characteristics of the initial flood surge suggests that the moving flood front tended to pick up debris from the stream channel during its flow downstream. This pro— gressive debris pickup of the leading flow edge probably created a front laden with sediment that moved rapidly but slower than the water behind it. The result was the abrupt arrival of a tremendous mass of debris and water. This type of debris-laden flood front has been described to the authors by several eyewitnesses of other flash floods. Field evidence of numerous other SEDIMENT 21 similar floods in Nevada also suggests this debris-laden front is a common characteristic of flash flooding in this environment. However, somewhat less common, in our experience, is the apparent increasing stage of more dilute streamflow following the initial debris-laden surge. This characteristic may be related to very intense flash flooding in a relatively large watershed having a complex major-tributary system wherein peak flows are more likely to occur sometime after the initial surge. This appears to have been the situation at Eldorado Canyon. In summary, throughout the terminal reaches of El- dorado Canyon below the junction of the three major washes, the sediment transport characteristics of the major floodflow appear to have been generally as fol- lows: (1) the initial surge was highly charged with sed- iment, artifacts, and uprooted vegetation; (2) the initial surge was followed by several succeeding surges, some of which were of higher stage than the initial surge; (3) surges following the initial onrush probably had a gen- erally lower sediment concentration than the initial surge. Dr. J. H. Sessums, Bishop, Calif, observed the flood- ing from quite a different vantage point, in Eagle Wash about 2 mi upstream from the trailer court (oral com- mun., 1974). Sessums was driving up Eagle Wash dur- ing the intense rain and hailstorm. His first encounter with fioodflow in Eagle Wash came as his moving car met several small pulses of flow. These pulses cumu- lated and increased the overall depth to a degree that prompted him to abandon his car. He did not observe any initial “wall” of water in Eagle Wash, nor any debris-clogged initial flow surge. He described the runoff as turbid, but definitely not a mudflow. Flow surges continued and added to the stream stage until Sessums’ car was swept downstream about a mile. It was subsequently deposited on the floor of the wash by the receding streamflow. Figure 24 pictures Sessums’ car on the afternoon of September 20 at its final resting place. The boulder deposited in front of the car was discussed earlier (p. 16). The car paint was unscratched in spite of the fact the car was partly inundated by rapidly flowing turbulent water for a substantial period of time. The flow apparently did not abrade or damage the paint surface, nor were there any visible signs of damage by large moving rocks. This evidence suggests that sediment transport in Eagle Wash apparently was dominated by gravel-size bedload that passed beneath the painted surface of the auto. The apparent domi- nance of gravel-size sediment agrees with the particle— size data of table 5. Absence of any scouring of the paint surface by suspended sand remains somewhat mysteri- ous to the authors. Sessums described his recollections of peak-flow con- ditions from his vantage point along Eagle Wash as a flow section 400 to 600 ft wide and about 4 to 6 ft deep. His description of the mobilization and transport of his car by the streamflow might provide useful evidence regarding the apparent absence of vehicles among the coarse-grained deposits at the mouth of Eldorado Can- yon. He observed his car being initially mobilized by a surge of flow that at some critical depth caused the front of the auto to pitch upward like the prow of a boat and begin moving downstream. Thereafter, the car ap- peared to bob along in the flow like a cork, aided by buoyancy caused by air trapped inside the body. This buoyancy may also have prevented prolonged sub- mergence with associated paint abrasion. If cars near the canyon mouth were likewise buoyed up by en- trapped air, they would be less likely to settle with coarse-grained sediments and would more likely be found considerably farther lakeward, among the finer- grained deposits. The fact that Sessums’ car moved downstream only 1 mi before being set down attests to the very short period of peak flow in Eagle Wash. EROSION Postflood air and ground reconnaissance of the drain— age basin disclosed abundant evidence of fresh erosion of rills, small tributary channels, and main channels throughout most of the basin. Generally, drainage areas upstream from main-channel reaches that experienced heavy runoff are relatively devoid of intensive rill— erosion scars. This relation between rill erosion and estimated peak flow rates in main channels generally agrees with apparent areal trends of total precipitation. All data suggest that precipitation, runoff, and erosion apparently were lowest in the headward parts of the basin. Intensities generally increased in a downstream direction and probably reached a maximum in the lower one-third of the basin. The most intense observed rill erosion was in a lower basin area (SEMLNWIA sec. 8, T. 26 S., R. 65 E.) shown in figure 25. In contrast, rill erosion is virtually absent in many parts of upstream areas such as that shown in figure 26, photographed approximately in the N1/2 secs. 8 or 9, T. 26 S., R. 64 E. Figure 26 shows that a minor amount of main-channel streamfiow and erosion did occur at the site, in spite of the lack of flow evidence on 22 .mmnmeofi wccuamom 6cm woouwamo @8383 min mimoaou unmEEmmISH $5on HYDROLOGY OF ELDORADO CANYON, NEV., FLOOD OF SEPTEMBER 14, 1974 mmmHmz Oma _ 1\\ Hawk coo .Aoa.wfiw uuwv uwmw Omen ounuwuam uumwuamnuwumz “qua .omxwa .umwm mo unwamuonm mumfiflxouaa< W>¢EOE MMEQ .Aquma Munouuo ..a=afiou HwMOV cowumadaumm we amwnsm .m.: .zcmwum .m.o kn vmzmflauaw .uoow umwummn cu wwvcnou .qmma .QH 5&5 Ba :3 6m .23 wow mumv cowum>waw ocHHmno:m .mwnum H.H usonm Oman mfiunou wCflumoaw mo wmu< .mmuum H.H uaonm >3 mumWHSm vama vwmmwuuaw cam wcHHmuonm vooawwum wfiomon ummw 0mm usonm monuuam wuma uwvcuuxw muflmomuu ucmfiwuwm vocab 00H on o _ _ fl _ T ._ _ o _ . ooq cow .uamw «mow wvzuwuam moduusmlumumz .vooam ouowmn umsm ¢mma .qa.uawm :0 mafiawuoam wumfiwxouam¢ ma uwnamumwm we coo: luvuwm no maunuv wufiumoam unnuunw wxma vooawumom Baden mufimomww usufifiwom acauwmonwv Eouw wafiuaamwu oUMMHDm vuwa sz wdwvsma umon no wuHmoaww unwaflvwm wdfivnma umon "muoz m>onm muflmoumu uawafivwm z o H H < z ¢ A m N m woa>uwm Mumm Hmaowumz ecu kn uwnmflnuaw mmE wmmm muHmomwv unwawvum uwumzuuvaa ca kuwUOH meUHcm> mo mace I o maxofia m.umw:¢u xuwm I m mmfiwom u < "muomhno vmuw>oumu mo mnoauMUOH mumafixoumm< SEDIMENT 23 FIGURE 18.—Excavated sediments quantitatively described in table 5. 24 FIGURE 19.—Stratified sediment deposited at the mouth of Eldorado Canyon. Note alternating layers of mixed particle sizes with only a general impression of coarsest sediment in lowest strata, the adjacent hill. Figure 5, an aerial view of lower basin terrain, shows distinctive rill-erosion scars. Intensive rill erosion is also clearly visible in figure 24, a photo- graph taken in NEML sec. 9, T. 26 S., R. 65 E., lower Eagle Wash. Large amounts of sediment derived by rill ero- sion were delivered to main channels and transported further. Much of the sediment transported by the September 14 flood, particularly the coarser grained fraction, prob- ably was derived by erosion from within the larger stream channels. Evidence of local vertical scour, gen- erally less than 1 ft in depth, was common. Deeper scour may have occurred in some places, followed by later redeposition. Figures 15, 22, and 24 show traces of rooted vegetation within high-intensity flow reaches. This evidence precludes any overall deep scouring. Severe lateral scour did occur in some places along majOr channels. Figure 27 shows examples of highway damage caused by this type of erosion. Although the flood of September 14 is believed to have HYDROLOGY OF ELDORADO CANYON, NEV., FLOOD OF SEPTEMBER 14, 1974 been the most severe in Eldorado Canyon during his— toric times, field reconnaissance disclosed some evi- dence of even more intensive erosion locally in at least one drainage tributary. Figure 28 shows a severe ero- sion scar on the steep southwest-facing slope of a hill in about SWMLSWML sec. 1, T. 26 S., R. 64 E., tributary to Techatticup Wash. The deeply furrowed channel is lat- erally bounded by windrow-shaped ridges of sizeable boulders that indicate very intense runoff and erosion. Vegetation growing within the furrowed channel and among the deposits indicate this feature substantially predates the September 14 flood. It does, however, show that other Violent runoff events have occurred during the past within the drainage. The hillslope in the background of figure 28, across the highway, shows additional severe rill erosion of the September 14 flood. ESTIMATED LANDSCAPE DENUDATION The estimate of total sediment deposited during the flood can be used to describe the effects of the flood in terms of overall landscape denudation. If the 100,000- ton estimate of deposits (table 4) is converted to a solid- rock equivalent and prorated uniformly over the 22.9— mi2 drainage basin, a mean basin denudation rate of about 0.002 ft is indicated for the flood. However, if the majority of eroded material was derived by main- channel erosion of temporarily stored alluvium, prorat- ing the sediment over the total basin would not be meaningful. Another approach, assuming dominant main-channel supply of detritus, would be to prorate the total sediment volume uniformly over the total length of mainstem channel. The sediment deposits above the postflood shoreline are about 34,000 yd3. The sub-lake- surface deposits (36,000 yd3) can be reduced to a land- surface volume equivalent of 25,000 yd3 by ratios of their unit weights. The resultant volume of equivalent main-channel deposits is about 60,000 yd3. Dividing that volume by the sum of main-channel lengths (25 mi) derived from figure 4 (Eldorado Canyon, 10.8 mi; Eagle Wash, 7.4 mi; and Techatticup Wash, 6.7 mi), the un— iform channel-denudation rate would be about 2,400 yd3/mi. Further, assuming the average channel width to be 100 ft, uniform vertical scour needed to supply the sediment from the main-channel system would require about 0.12 ft of average downcutting. Obviously, none of the above statistical manipulations satisfy the true ero- sion picture; however, they may provide a crude refer- ence for regional comparison with other runoff events. ACKNOWLEDGMENTS The US. Geological Survey gratefully acknowledges major financial assistance from the US. National Park ACKNOWLEDGMENTS 25 FIGURE 20.—Floating debris at the mouth of Eldorado Canyon. Photograph on afternoon of September 15, about 24 hours after flood and before any significant cleanup of debris. FIGURE 21.—Downstream view of boulder deposits that probably FIGURE 22.—Large boulder that probably moved during flood in lower moved on September 14 in Techatticup Wash. reaches of Eldorado Canyon. -% 26 HYDROLOGY OF ELDORADO CANYON, NEV., FLOOD OF SEPTEMBER 14, W74 FIGURE 23.——Position of high water line at canyon narrows just upstream from former restaurant. Note people standing on high water line for scale. 1 Service in the investigation and the preparation of this 1 report. The authors would like to express their appreciation to many people who provided help and information dur- ing this investigation. T. R. Gess, Engineer, U.S. Na— tional Park Service, was particularly helpful. Many others in the Park Service at Lake Mead National Re- creational Area also provided assistance, including: William J. Briggle, Park Superintendent, Gary E. Bun~ ney, Assistant Superintendent, Frank J. Deckert, Gene F. Gatzke, David E. Hoover, David J. McLean, James L. Monheiser, Richard Rundell, and J. D. Vanderford. As— FIGURE 24.-7An automobile at rest in lower Eagle Wash after about a 1—mile transit in flood. sistance and information was also provided by Richard Mayne, Clark County Coroner; Dr. Gerald Williams and Reid Garner of the US. National Weather Service; James Pomcroy and staff of the Materials and Testing Laboratory, Nevada Highway Department, Las Vegas; several members of the Nevada Highway Department in Carson City who furnished aerial photographs and gravel sample bags; R. J. Gregory, Director, Nevada Civil Defense and Disaster Agency; A. R. Methvan, Thomas Jester, and Murl Emry, Nelson residents; Ken- FIGURE 25.—-Evidence of intense rill lower Eldorado Canyon. erosion in unnamed tributary to REFERENCES CITED 27 FIGURE 27.—«Highway damage in Techatticup Wash caused mainly by lateral channel scour. neth E. Beales, for permission to publish his photograph of flood flow; and John Gallifent, Lemuel Washington, Mr. and Mrs. Kirby L. Koop, and Dr. J. H. Sessums, eyewitnesses to the flood. The authors apologize for anyone who helped but was inadvertently omitted from the foregoing list. Without the help of all, many details and interpretations in this report would have been impossible. REFERENCES CITED Casebier, D. G., 1970, Camp El Dorado, Arizona Territory: Tempe, Arizona Historical Foundation, Arizona Mon. N0. 2, 103 p. Dalrymple, Tate, and Benson, M. A., 1967, Measurement of peak discharge by the slope-area method: U.S. Geol. Survey Techniques Water-Resources Inv., Book 3, ch. A2, 12 p. FIGURE 26.—Evidence of minor channel flow and only minimal rill erosion in Copper Canyon. Fenneman, N. M., 1931, Physiography of Western United States: New York and London, McGraw—Hill Book Campany, Inc., 534 p. Hough, D. K., 1957, Basic soils engineering: New York, The Ronald Press Company, 513 p. Hoyt, W. G., and Langbein, W. B., 1955, Floods: Princeton Univ. Press, 469 p. Longwell, C. R., 1963, Reconnaissance geology between Lake Mead and Davis Dam, Arizona-Nevada: U.S. Geol. Survey Prof. Paper 374E, p. 137—1351. FIGURE 28.—Windrows of boulders bordering a pre-September 14, 1974 erosion scar. 28 HYDROLOGY OF ELDORADO CANYON, NEV., FLOOD OF SEPTEMBER 14, 1974 Longwell, C. R., Pampeyan, E. H., Bowyer, Ben, and Roberts, R. J ., Colorado: US. Geol. Survey Water-Supply Paper 1850—B, p. 1965, Geology and mineral deposits of Clark County, Nevada: B1—B64. Nevada Bur. Mines Bull. 62, 218 p. Moore, D. 0., 1974, Estimating flood discharges in Nevada using Matthai, H. F., 1969, Floods of June 1965 in South Platte River basin, channel-geometry measurements: Carson City, Nevada Highway Dept. Hydrologic Rept. 1, 43 p. DES. GOVERNMENT PRINTING OFFICE: 1975-0-689-910/82