i% (V< . . * rite;-':.:'- ■-■'.'^^^ !inai(:,t!(!;!;|M:|f j(vVi^;;!C^— :■:. ,!r^- ;;Ui);?;^;;.,;,v;.;;: ;;. . :;l;i;i;;','. '.",;.. './v.,*'*". 1:' ,• ■ .;. .,., ,,,,(wlA7li*'t.i.f' t- ' , , ; , , f^V'" :'. ,,.1, ,,.i,k.i(i«< • <• I'lill-yti/j.WnJv'"':"-;' r,;;v,\.c. v ■,-; \H!r'-in\X Glass GtB 7Q 5_ Book .A^£.^ Digitized by the Internet Archive in 2011 with funding from The Library of Congress http://www.archive.org/details/surfacewatersuppOOells DEPARTMENT OF THE INTERIOR UNITED STATES GEOLOGICAL SUKVEY GEORGE OTIS SMITH, Director WATER-SUPPLY PAPER 342 SURFACE WATER SUPPLY OF THE ii^. YUKON-TANAM REGION, ALASKA BY C. E. ELLSWORTH AND R. W. DAVENPORT WASHINGTON GOVERNMENT PRINTING OFFICE 1915 M onofifranh DEPARTMENT OF THE INTERIOR UNITED STATES GEOLOGICAL SURVEY GEORGE OTIS SMITH, Director Water- Supply Paper 342 /y SURFACE WATER SUPPLY ¥^l OF THE YUK0?(-™MA EEGIOli, ALASKA BY C. E. ELLSWORTH AND R. W. DAVENPORT WASHINGTON GOVERNMENT PRINTING OFFICE 1915 ^ Vv^ JUi< 8 1915 vfi ii ^ CONTENTS, Page. Preface, by Alfred H. Brooks 9 Introduction H Scope of investigation 11 Di\dsion of work and acknowledgments 12 Publications I3 General features of Yukon-Tanana region '. I7 Geography 17 Geology 17 Climate 18 General features 18 Temperature 19 Precipitation 23 Vegetation 41 Transportation 43 Water-supply conditions and their economic effect 45 Seasonal distribution 45 Effect of topography 46 Winter supply 46 Winter glaciers 46 Run-off 47 Supply available for mining purposes 48 Stream flow 49 Terms used 49 Convenient equivalents 50 Field methods r 50 Office methods 53 Explanation of tables and use of data 54 Accuracy of data 56 Regular gaging stations 57 Yukon River drainage basin 60 Description 60 Yukon River at Eagle 62 Yukon River at Rampart 66 Fiftymile River at W^hitehorse, Yukon Territory 67 Fortymile River drainage basin 67 Description 67 Main stem of Fortymile River 68 Description 68 Dennison Fork at mouth 68 South Fork of Fortymile River drainage basin 70 Description 70 South Fork at Franklin 70 Fortymile River at Steel Creek 73 3 4 CONTENTS. Stream flow — Continued. Fortymile River drainage basin — Continued. South Fork of Fortymile River drainage basin — Continued. Page. Mosquito Fork at Kechumstuk 76 Kechumstuk Creek at mouth 79 Gold Creek at mouth 81 Walker Fork above Poker Creek 82 Walker Fork above Cherry Creek 83 Walker Fork above Twelvemile Creek 84 Wade Creek at claim "No. 10 above" 85 Buckskin Creek above Fortyfive Pup 88 Fortyfive Pup at claim No. 13 91 Miscellaneous measurements 94 North Fork of Fortymile River drainage basin 94 Description 94 North Fork of Fortymile River at the "kink " 95 North Fork of Fortymile River above Middle Fork 97 Confederate Creek at mouth 98 Hutchinson Creek below Confederate Creek 98 Hutchinson Creek below Montana Creek 100 Montana Creek at claim "No. 7 above " 102 Miscellaneous measurements 105 Lower Fortymile River drainage basin 105 Description 105 King Solomon Creek at Liberty Cabin 106 Liberty Fork at mouth 108 Dome Creek at Auburn Mining Co. 's camp 109 Steel Creek at mouth Ill Canyon Creek below Squaw Gulch 113 Squaw Gulch at claim "No. 1 above" 116 ]\liscellaneous measurements • 119 Mission Creek drainage basin 120 Description 120 Mission Creek above Oregon Creek 120 Mission Creek above Colorado Creek 121 Wolf Creek above Swanson's dam 121 American Creek at claim "No. 8 above " 122 American Creek at United States pumping plant 125 Discovery Fork of American Creek below Star Gulch 127 Miscellaneous measurements 131 Seventymile River drainage basin 131 Description 131 Seventymile River above Flume Creek 132 Seventymile River at the falls 134 Flume Creek one-fom'th mile above mouth 137 Alder Creek at claim "No. 7 above " 140 Barney Creek above ditch intake 143 Barney Creek ditch below the forks 144 Sonickson Creek above ditch intake 145 Washington Creek above dam 147 Crooked Creek below Eldorado Creek 149 Fox Creek at Rolf's claim 151 Miscellaneous measurements 154 CONTENTS. 5 Stream flow — Continued. Page. Washington Creek drainage basin 154 Birch Creek drainage basin 155 Description 155 Bii-ch Creek above Twelvemile Creek 156 Birch Creek below Twelvemile Creek 157 Birch Creek below Great Unknown Creek 159 Birch Creek below Clums Fork 160 Bii"ch Creek above Sheep Creek 162 Birch Creek at Fourteenmile House 164 Mastodon Fork of Eagle Creek above storage dam 169 Fryingpan Creek below forks 170 Great Unknown Creek at mouth 171 • Clums Fork below Munson Creek 172 Lawson Creek at mouth 173 Buckley Bar Creek at mouth 174 Sheep Creek at mouth 176 Bachelor Creek below Costa Fork 178 Miscellaneous measurements : 180 Crooked Creek drainage basin 181 Description 181 Porcupine Creek above ditch intake 182 Porcupine Creek below ditch intake 184 Porcupine Creek below Bonanza Creek 185 Crooked Creek at Central House 188 Bonanza Creek above ditch intake 192 Bonanza Creek below ditch intake 194 Independence Creek at claim "No. 9 above " 195 Mammoth Creek at Miller House 196 Mammoth Creek diversion ditch 198 Miller Creek at mouth 199 Deadwood Creek above Switch Creek 200 Portage Creek 4 miles above Medicine Lake 204 Porcupine ditch at intake 205 Bonanza ditch at intake 206 Bonanza ditch below junction with Porcupine branch 209 Bonanza ditch near outlet ' 210 Miscellaneous measurements 212 Beaver Creek drainage basin 212 Description 212 Nome Creek 4 miles above Moose Creek 213 Nome Creek above Ophir Creek. . . , 214 Miscellaneous measurements 217 Hess Creek drainage basin 217 Description 217 Troublesome Creek below Quail Creek 218 Quail Creek at claim "No. 7 above" 219 Quail Creek at claim "No. 9 below " 221 Miscellaneous measurements 222 Minook Creek drainage basin 223 Description 223 Minook Creek above Little Minook Creek 225 Hoosier Creek at claim "No. 11 above" 227 Little Minook Creek at claim "No. 9 above" 229 6 CONTENTS. Stream flow — Continued. Minook Creek drainage basin — Continued. Page. Hunter Creek at claim "No. 17 above" 232 Mscellaneous measurements 233 Squaw Creek 233 Russian Creek 233 Tanana Biver drainage basin 233 Description 233 Tanana River at McCartys 234 Tanana River below Chena 234 Banner Creek at mouth 235 Miscellaneous measurements 237 Salcha River drainage basin 238 Description 238 Salcha River at mouth ^ 238 Junction Creek above Moose Lake outlet 240 Chena River drainage basin 243 Description 243 Chena River above Shamrock Creek 244 Chena River above Little Chena River 245 North Fork of Chena River above Monument Creek 248 North Fork of Chena River below Monument Creek 249 Monument Creek at Chena Hot Springs 250 Miscellaneous measurements 251 Little Chena River drainage basin 251 Description 251 Little Chena River above Sorrels Creek ....*. 252 Little Chena River below Fish Creek 255 Sorrels Creek above Elliott Creek 257 Elliott Creek near mouth 259 Fish Creek below Solo Creek 261 Fish Creek above Fairbanks Creek 264 Fish Creek at mouth 266 Miller Creek at mouth 268 Miscellaneous measurements 270 Tolovana River drainage basin 270 Description 270 West Fork of Tolovana River drainage basin 271 Description 271 Miscellaneous measurements 271 Washington Creek drainage basin 272 Description 272 Washington Creek above Aggie Creek 272 Washington Creek below Aggie Creek 273 Aggie Creek at mouth 275 Chatanika River drainage basin 276 Description 276 McManus Creek at mouth 277 Chatanika River below Faith Creek 280 Chatanika River below Poker Creek 285 Chatanika ditch near outlet 291 Smith Creek above Pool Creek 292 Pool Creek at mouth 294 Faith Creek at mouth 295 CONTENTS. 7 Stream flow — Continued. Tolovana River drainage basin — Continued. Chatanika River drainage basin — Continued. Page. Charity Creek above Homestake Creek 297 Homestake Creek at mouth 299 Kokomo Creek above Alder Creek 301 Miscellaneous measurements 302 Goldstream Creek drainage basin 303 Description 303 Goldstream Creek at claim "No. 6 below" 304 Miscellaneous measurements 306 Baker Creek drainage basin 306 Description 306 Baker Creek at road crossing 307 New York Creek at ditch intake 308 California Creek at ditch intake 310 Thank^iving ditch near outlet 311 California branch of Thanksgiving ditch near intake 313 Mscellaneous measurements 314 Eureka Creek drainage basin 315 Description 315 Pioneer Creek at What Cheer Bar ditch intake 315 ^Tiat Cheer Bar ditch near intake 317 Miscellaneous measurements 318 Hutlinana Creek drainage basin 319 Description 319 Hutlinana Creek near Cairo Creek 320 Miscellaneous measurements 322 Patterson Creek drainage basin 323 Description 323 Sullivan Creek above Tofty ditch intake 323 Miscellaneous measurements 324 Minimum discharge 325 Water power 326 General conditions 326 Power sites 328 Fortymile River basin 328 Seventymile River basin 329 Birch Creek basin 330 Chatanika River basin 330 Washington Creek 331 Chena River basin 331 Summary 331 Hydraulic methods 332 Conclusions 336 Index 339 ILLUSTRATIONS. Page. Plate I. Map of Alaska, showing location of Yukon-Tanana region 16 II. Map showing distribution of timber in Yukon-Tanana region 40 III. A, Small Price current meters; B, Wading measurement 52 IV. Key map showing approximate location of gaging stations 56 V. A, Yukon River at Eagle; B, Fortymile River below Steel Creek 62 VI. A, Typical topography, Mastodon Creek; B, Hydraulicking on Eagle Creek 63 VII. A, Quail and Troublesome creeks; Wolverine Mountain in the distance; B, Little Minook Creek 218 VIII. Hydrograph showing daily discharge in second-feet of Chatanika River below Poker Creek from 1907 to 1912 286 IX. A, North Fork of Fortymile River at the ''kink " ; B, Falls on Seventy- mile River 328 X. Reconnaissance map of the Fortymile quadrangle In pocket. XI. Reconnaissance map of the Circle quadrangle In pocket, XII. Reconnaissance map of the Fairbanks quadrangle In pocket, XIII . Reconnaissance map of the Rampart quadrangle In pocket. Figure 1. Index map showing location of quadrangles in Yukon-Tanana region 16 2. Fluctuation of annual rainfall at Alaska stations 40 3. Average mean monthly precipitation at seven Weather Bureau stations in the Yukon-Tanana region 40 4. Discharge, area, and mean-velocity curves of Fortymile River at Steel Creek 55 5. Cross section of Yukon River at measuring section at Eagle 62 8 PREFACE. By Alfred H. Brooks. The following report presents the results of six years of observa- tions on water supply of the Yukon-Tanana region. Unfortunately the records are very unequally distributed, both geographically and as to length of observations. Records of run-off have been obtained for six years at Fairbanks, for five years in the Birch Creek district, for three years in the Fortymile district, and for shorter periods in other districts. Moreover, although this report throws light on the water supply of the entire Yukon-Tanana region, yet large areas in this region have not been visited by the engineers who have carried on this investigation. It is believed, however, that the data pre- sented make it possible to estimate the run-off of streams which have not been gaged and will serve as a valuable guide to the hydrauHc engineer who is seeking a supply of water. It need hardly be added that such use of the report will not take the place of the careful measurement of water supply that must precede any exten- sive installations. Such use, however, should make this report of great value to the placer-mining industry of the region. Mr. Ellsworth and his associates deserve great credit for the results here achieved. Much of the work was carried on under great diffi- culties because of the unsettled condition of the region. The engi- neers have for the most part worked alone. Their investigations outside of the established mining camps have involved journeys which have put their physical endurance to severe tests and have involved considerable hardship. In view of the demands for surveys in other parts of Alaska it is necessary for the present to discontinue stream gaging in the Yukon- Tanana region. For this reason this summary report has been pre- pared in the hope that it will meet the more pressing demands for information about the water supply. It is hoped that before long money will be available to resume the work in some parts, at least, of the Yukon-Tanana region, for it is beheved that at least 10 years' observations should be obtained in every district where extensive use of water supply is likely to be made. 9 SURFACE WATER SUPPLY OF THE YUKON-TANANA REGION, ALASKA, 1907 TO 1912. By C. E. Ellsworth and E,. W. Davenport. INTRODUCTION. SCOPE OF INVESTIGATION. A study of the surface water supply of the Yukon-Tanana region was begun in 1907 and was continued each season till the end of that of 1912. The essential part of the information thus obtained has been made available for general distribution as soon as practicable after the close of each field season through the medium of the annual report on the mineral resources of Alaska. A detailed report of the work of 1907 and 1908 was also published as Water-Supply Paper 228. Now that water-supply studies are to be discontinued indefinitely in this region it is desirable that all the data accumulated shall be brought together in one volume, with such additions and revisions as seem proper in the light of more complete knowledge. The points at which gaging stations have been maintained were determined largely by the location at which gage observers were available. Many streams on which records of daily discharge were highly desirable were so isolated as to be beyond reach with the small allotments available. Further, many stations could not be located at the most desirable points for obtaining accurate results or even with reference to the places at which information was most likely to be requested. The duration of the records (one year to six years) is insufficient to show the extreme limits of flow that should be expected. Notwithstanding all this, however, it is beheved that the records, if used with proper care and with due allowance for accuracy, duration, and location, will satisfy most of the needs of miners. It should be emphasized that before any extensive development is undertaken on any stream these records should be supplemented by a more detailed study of the particular water supply. 11 12 SUKFACE WATER SUPPLY OF YUKON-TAN ANA REGION, ALASKA. DIVISION OF WORK AND ACKNOWLEDGMENTS. The hydrometric surveys, the results of which are published in this report, were carried on under the appropriation for the investigation of the mineral resources of Alaska by engineers detailed for this purpose from the water-resources branch of the United States Geo- logical Survey. The work has been under the general supervision of Alfred H. Brooks, geologist in charge of Alaskan work. The first work of this nature to be undertaken in the Yukon-Tanana region was begun in the Fairbanks district in June, 1907, by C. C. Covert, who established a few regular gaging stations and made a general reconnaissance of that district until September 23 of that year. During the season of 1908 work was continued by C. C. Covert and C. E. Ellsworth. In March, 1908, Mr. Covert went to the Fairbanks district to gather data on the spring run-off from the melting snow, and later in the season he extended the work to the Rampart and Hot Springs districts. In June Mr. EUsworth and Mr. Covert met at Circle and made a reconnaissance trip across country to Fairbanks and estabhshed a few regular gaging stations in the Birch Creek basin. On August 1 Mr. Ellsworth went to the Rampart and Hot Springs districts, where he continued the work until September 22. Mr. Covert and the rest of the party remained in the Fairbanks district until the end of August, when they started back to Circle, arriving there September 15. Much credit for the amount of data obtained and the extended territory which the party was able to cover is due to George Neuner, jr., field assistant, who made many of the measure- ments, and to C. E. Anderson, who acted as cook and packer. The work of 1909 was carried on by Mr. Ellsworth from April 1 to September 12. As many of the old stations as possible were con- tinued and a few new ones were established. Two trips were made up Tanana River as far as McCarty's, in addition to the work in the Fairbanks, Rampart, Hot Springs, and Circle districts. On April 1, 1910, Mr. Ellsworth and G. L. Parker arrived at Fair- banks and commenced field work in that district. Early in June, after having commenced the investigation in the Fairbanks and Circle districts, Mr. Ellsworth proceeded to Eagle and studied the water supply in the Fortymile, Eagle, and Seventymile districts until the later part of September. Mr. Parker continued work in the Fair- banks, Circle, and Salchaket districts for the remainder of the season. In view of the needs and possibilities of the several districts, the slow means of transportation, and the scanty funds available, it was decided to discontinue the work in the Rampart and Hot Springs districts. INTEODUCTION. 13 In 1911 the work was carried on by Mr. Ellsworth and E. A. Porter, who arrived at Eagle in the middle of April and spent most of the time until May 27 in installing a gage and determining the flow of Yukon Kiver, in establishing several minor stations, and in making general plans for the season. Mr. Ellsworth then went to Circle and continued the field work until August 22. Mr. Porter continued field work in the Fortymile, Eagle, and Seventymile districts until about the middle of September. The investigations of 1912 covered about the same areas as in 1911. Mr. Ellsworth and E,. W. Davenport arrived at Eagle May 19 and commenced field work which ended about the middle of September. Mr. Ellsworth continued the investigations in the Fairbanks and Circle districts, and Mr. Davenport took up similar work in the Fortymile, Eagle, and Seventymile areas. J. C. Hoyt, engineer in charge of surface water supply investiga- tions, has given valuable advice regarding general plans for field work and the preparation of reports. For gage readings and assistance in making discharge measure- ments in the Little Chena River basin, special credit is due to Sherman White icL 1907 and 1908 and to T. J. Shaw in 1910. It would be almost impossible to give individual credit to all who assisted in the work. The most hospitable treatment and kindly aid have been extended at all times by residents of this region to members of the Survey. Individual credit for assistance in obtaining gage readings and discharge measurements is given in coimection with the published data. Particular acknowledgment is due to the following persons who through cooperation or definite assistance contributed directly toward the prosecution of the work: Mr. John Zug, superintendent of the Alaska Road Commission; Mr. C. W. McConaughy, chief enguieer of the Chatanika Ditch Co.; Mr. Falcon Joslin, president of the Tanana Valley Railroad Co.; Mr. Herman Wobber, Fairbanks Creek; Mr. Martin Harris, Chena Lumber & Light Co., Chena; Mr. W. H. Par- sons, general manager of the Washington- Alaska Bank; Mr. F. G. Manley, Baker Hot Springs; Mr. A. V. Thorns, superintendent of the Manley mines. Baker Hot Springs; Mr. M. E. Koonce, Rampart; employees of the Northern Commercial Co. and the Mammoth Creek Mining Co., Circle; and Louis Greul, Fairbanks. PUBLICATIONS. The geology, topography, mining industry, and general features of the area have been discussed at length by geologists and others detailed from the United States Geological Survey. The follo^ving is a partial list of the reports that have been published. Those marked with an asterisk (*) are out of stock at the Survey but can 14 SURFACE WATER SUPPLY OF YUKON^-TANANA REGION, ALASKA. be purchased from the superintendent of documents at the prices stated. Reports of an expedition to the Copper, Tanana, and Koyukuk rivers in the Terri- tory of Alaska, by H. T. Allen, 1887, 172 pp.^ ^Geology of the Yukon gold district, Alaska, by J. E. Spurr. Eighteenth Annual Report, pt. 3, 1898, pp. 87-392. |2.15, A reconnaissance in the White and Tanana river basins, Alaska, by A. H. Brooks. Twentieth Annual Report, pt. 7, 1900, pp. 425-494. The Mount McKinley region, Alaska, by A. Hi Brooks, with descriptions of the igneous rocks and of the Bonnifield and Kantishna regions, by L. M. Prindle. Pro- fessional Paper 70, 1911. *The geography and geology of Alaska, a summary of existing knowledge, by A. H. Brooks, with a section on climate by Cleveland Abbe, jr., and a topographic map and a description thereof by R. U. Goode. Professional Paper 45, 1906, 327 pp. $1. ^Methods and costs of gravel and placer mining in Alaska, by C. W. Purington. Bulletin 263, 1905, 362 pp. 35 cents. ■^Geographic dictionary of Alaska, by Marcus Baker; second edition, prepared by James McCormick. Bulletin 299, 1906, 690 pp. 50 cents. Railway routes in Alaska. 62d Cong., 3d sess., H. Doc. No. 1346.^ *The coal resources of the Yukon, Alaska, by A. J. Collier. Bulletin 218, 1903, 71 pp. 15 cents. ^The gold placers of the Fortymile, Birch Creek, and Fairbanks regions, by L. M. i*rindle. Bulletin 251, 1905, 89 pp. 35 cents. Yukon placer fields, by L. M. Prindle. Bulletin 284, 1906, pp. 109-131. Reconnaissance from Circle to Fort Hamlin, by R. W. Stone. Bulletin 284, 1906, pp. 128-131. The Yukon-Tanana region, Alaska; description of the Circle quadrangle, by L. M. Prindle. Bulletin 295, 1906, 27 pp. The Bonnifield and Kantishna regions, by L. M. Prindle. Bulletin 314, 1907, pp. 205-226. *The Circle precinct, by A. H. Brooks. Bulletin 314, 1907, pp. 187-204. 30 cents. *The Yukon-Tanana region, Alaska; description of the Fairbanks and Rampart quadrangles, by L. M. Prindle, F. L. Hess, and C. C. Covert. Bulletin 337, 1908, 102 pp. 25 cents. *Occurrence of gold in the Yukon-Tanana region, by L. M. Prindle. Bulletin 345, 1908, pp. 179-186. 45 cents. *The Fortymile gold-placer district, by L. M. Prindle. Bulletin 345, 1908, pp. 187-197. 45 cents. *The Fairbanks gold-placer region, by L. M. Prindle and F. J. Katz . Bulletin 379, 1909, pp. 181-200. 50 cents. *Water supply of the Yukon-Tanana region, 1907-8, by C. C. Covert and C. E. Ellsworth. Bulletin 379, 1909, pp. 201-228. 50 cents. *Gold placers of the Ruby Creek district, by A. G. Maddren. Bulletin 379, 1909, pp. 229-233. 50 cents. *Placers of the Gold Hill district, by A. G. Maddren. Bulletin 379, 1909, pp. 234- 237. 50 cents. *Gold placers of the Innoko district, by A. G. Maddren. Bulletin 879, 1909, pp. 238-266. 50 cents. The Innoko gold-placer district, Alaska, with accounts of the central Kuskokwim Valley and the Ruby Creek and Gold Hill placers, by A. G. Maddren. Bulletin 410, 1910, 87 pp. 1 Not a publication of the U. S. Geol. Survey. INTRODUCTION. 1 5 Sketch of the geology of the northeastern part of the Fairbanks quadrangle, by L. M. Prindle. Bulletin 442, 1910, pp. 203-209. The auriferous quartz veins of the Fairbanks district, by L. M. Prindle. Bulletin 442, 1910, pp. 210-229. Placer mining in the Yukon-Tanana region, by C. E. Ellsworth. Bulletin 442, 1910, pp. 230-245. Occurrence of wolframite and cassiterite in the gold placers of Deadwood Creek, Birch Creek district, by B. L. Johnson. Bulletin 442, 1910, pp. 246-250. Water supply of the Yukon-Tanana region, 1909, by C. E. Ellsworth. Bulletin 442, 1910, pp. 251-283. The Koyukuk-Chandalar gold region, by A. G. Maddren. Bulletin 442, 1910, pp. 284-315. Placer mining in the Yukon-Tanana region, by C. E. Ellsworth and G. L. Parker. Bulletin 480, 1911, p. 172. Water supply of the Yukon-Tanana region, 1910, by C. E. Ellsworth and G. L. Parker. Bulletin 480, 1911, p. 217. Mineral resources of the Bonnifield region, by S. R. Capps. Bulletin 480, 1911, p. 235. Gold placer mining developments in the Innoko-Iditarod region, by A. G. Maddren. Bulletin 480, 1911, p. 270. The Bonnifield region, Alaska, by S. R. Capps; including geologic and topographic reconnaissance maps. Bulletin 501, 1912, 162 pp. *Placer mining in the Fortymile and Seventymile river districts, by E. A. Porter. Bulletin 520, 1912, pp. 211-218. 50 cents. *Water supply of the Fortymile, Seventymile, and Eagle districts, by E. A. Porter. Bulletin 520, 1912, pp. 219-239. 50 cents. ■'^Placer mining in the Fairbanks and Circle districts, by C. E . EUsworth. Bulletin 520, 1912, pp. 240-245. 50 cents. *Water supply of the Fairbanks, Salchaket, and Circle districts, by C. E. Ellsworth. Bulletin 520, 1912, pp. 246-270. 50 cents. *The Rampart and Hot Springs regions, by H. M. Eakin. Bulletin 520, 1912, pp. 271-286. 50 cents. *The Ruby placer district, by A. G. Maddren. Bulletin 520, 1912, pp. 287-296. 50 cents. *Gold placers between Woodchopper and Fourth of July creeks, upper Yukon River, Alaska, by L. M. Prindle and J. B. Mertie, jr. Bulletin 520, 1912, pp. 201-210. 50 cents. A geologic reconnaissance of the Fairbanks quadrangle, Alaska, by L. M. Prindle, with a detailed description of the Fairbanks district by L. M. Prindle and F. J. Katz and an account of lode mining near Fairbanks by P. S. Smith. Bulletin 525, 1913,220 pp. The Koyukuk-Chandalar region, Alaska, by A. G. Maddren. Bulletin 532, 1913, 119 pp. A geologic reconnaissance of a part of the Rampart quadrangle, Alaska, by H. M. Eakin. Bulletin 535, 1913, 38 pp. A geologic reconnaissance of the Circle quadrangle, Alaska, by L. M. Prindle. Bulletin 538, 1913, 82 pp. The Yukon-Tanana region south of latitude 66° (except a small triangular area north of the Fortymile quadrangle), embracing an area of over 40,000 square miles, has been entirely covered by topo- graphic surveys on a scale of 1 : 250,000 (approximately 4 miles to the inch) with 200-foot contour intervals. (See fig. 1.) The Fortymile 16 SUEFACE WATER SUPPLY OF YUKON-TANANA EEGIOI^, ALASKA. quadrangle was surveyed in 1898 and the remaining areas during 1903 to 1910. An area of about 500 square miles, covering the most important part of the Fairbanks mining district, was topographically surveyed on a scale of 1 : 62,500 with 25-foot contour intervals in 1907. The following is a list of published maps covering this and adjacent areas: Fortymile quadrangle; No. 640; scale, 1:250,000; by E. C. Barnard. Price 10 cents a copy or $6 a hundred. Fairbanks quadrangle; No. 642; scale, 1:250,000; byT. G. Gerdine, D. C. Wither- spoon, and R. B. Oliver. Price 50 cents a copy. 200 Miles Figure 1.— Index map showing location of quadrangles in Yukon-Tanana region. Rampart quadrangle; No. 643; scale, 1:250,000; by D. C. Witlierspoon and R. B. Oliver. Price 20 cents a copy or $12 a hundred. Fairbanks district; No. 642A; scale, 1:62,500; byT. G. Gerdine and R. H. Sargent. Price 20 cents a copy or $12 a hundred. Yukon-Tanana region, reconnaissance map of; scale, 1:625,000; byT. G. Gerdine. Contained in Bulletin 251, 1905. Not published separately. Fairbanks and Birch Creek districts, reconnaissance maps of; scale, 1:250,000; by T. G. Gerdine. Contained in Bulletin 251, 1905. Not published separately. Circle quadrangle, Yukon-Tanana region; No. 641; scale, 1:250,000; byD. C. With- erspoon. Contained in Bulletin 295. Price 50 cents a copy. Upper Tanana River and Ladue Creek region; scale, 1:250,000; by D. C. Wither- spoon and J. W. Bagley. In preparation. The Bonnifield region; scale, 1:250,000; by J. W. Bagley, D. C. Witherspoon, and C. E. Giffin. Contained in Bulletin 501; not published separately. u. s, WATER-SUPPLY PAPER 342 PLATE ( U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 342 PLATE I t>y(_)VJ /igable Limit of sea i mer in winter / / fj\ Is ^ co.siii^l ^^somrHa, Ko' .^^^ j>f' ma- Sat, i?° Cwp5FC^'=[- hfi^\ Chitina^ 100 200 300 MILES ^. MAP OF ALASKA SHOWING LOCATION OF YUKON-TANANA REGION. GENERAL FEATURES. 17 GENERAL FEATURES OF YUKON-TANANA REGION. GEOGRAPHY. 1 The Yukon-Tanana region comprises the part of east-central Alaska bounded by Yukon and Tanana rivers and the international boundary between Canada and Alaska. (See PL I.) It covers an area of over 40,000 square miles with a maximum north and south extent of about 175 miles. The distance from the boundary to the junction of the two rivers is nearly 300 miles. The Yukon-Tanana region forms part of the central plateau prov- ince of Alaska. It is an upland which may be termed a dissected plateau, diversified by many broad valleys and their smaller tribu- taries and characterized by broad flat interstream areas, above which rise numerous rounded domes and some good-sized mountain masses. The surface of the upland maintains remarkable uniformity of alti- tude throughout considerable areas; it stands at an altitude of 3,000 to 3,500 feet in the eastern part of the region, gradually falls off west- ward to the vicinity of Fairbanks, where it is only about 2,000 feet in altitude, and rises again to 3,000 feet near the Yukon at Rampart. In many parts of the region flat-topped spurs stand below the general level. The domes, which rise above the general level, are irregularly dis- tributed and attain altitudes of 4,000 to 5,000 feet. Some mountains with well-defined crest lines also stand 4,000 to 5,000 feet above sea level; among them are the Glacier Mountains, in the Fortymile region, 5,000 to 6,000 feet high; the Crazy Mountains, near Circle, 3,000 to 3,600 feet high; the White Mountains, in the Beaver Creek drainage basin, 3,000 to 4,000 feet high; and the Sawtooth Mountains, near Rampart, nearly 5,000 feet high. The domes are almost entirely composed of stocks of igneous rock and owe their present prominence to the resistance to weathering of these rocks. Some of the moun- tains are made up of igneous rocks and some of closely folded sedi- ments, but in both types the relief is due to the greater resistance to erosion of their constituent rocks. GEOLOGY.2 Two dominant structural trends of Alaska, one southeast and northwest and the other northeast and southwest, intersect the Yukon-Tanana region and give to the province an important struc- tural position. Numerous individual formations also possess com- plicated structures. The field has been one of sedimentation, diastrophism, widespread metamorphism, abundant intrusion, and volcanic action. Its position, furthermore, in the basin of the 1 Prindle, L. M., Katz, F. J., and Smith, P. S., A geological reconnaissance of the Fairbanks quadrangle, etc.: U. S, Geol. Siirvey Bull. 525, pp. 17-18, 1913. 2ldem, pp. 30-32. 42913* — wsp 342—15 2 18 SUEFACE WATER SUPPLY OF YUKON-TAN ANA REGION, ALASKA. Yukon, one of the great drainage systems of the world, has subjected it to long-continued and intricate fluviatile modeling. As it lies outside the widely glaciated region, its topography is due almost exclusively to subaerial denudation. Finally, its bedrock is mantled with unconsolidated deposits, which, though but the product of an episode of geologic history, are nevertheless of great importance with reference to the distribution of placer gold. The rocks include essentially two great groups, one of metamorphic completely folded schists of pre-Ordovician age, and another, uncon- formable in its relation to the schists, made up of folded argillites, quartzite, conglomerate, sandstone, altered volcanic rocks, and lime- stone ranging in age from Ordovician to Carboniferous. Besides these two groups some areas of Lower Cretaceous quartzites and slates and of Eocene friable sandstones, shales, and lignitic coal are found. Igneous rocks are represented in this field by many large areas of granites and by dikes of varied composition. The uncon- solidated materials of the province are primarily the alluvial deposits of the valleys and the terrace deposits of gravel, sand, and silt which are developed along Yukon and Tanana rivers. The mineral resources of the region consist of placer gold, found in the Fairbanks, Birch Creek, Fortymile, Hot Springs, and other districts, and of auriferous and other metalliferous lodes which occur at many places but have been developed only in the Fairbanks district. Most of the developed gold deposits occur in the older schistose rocks and in areas where intrusive rocks are abundant. Gold has, how- ever, been found in other associations. About $75,000,000 worth of gold has been mined in the Yukon-Tanana region. Some silver has been recovered incidental to gold mining, and antimony, silver- ead, and tin ores have been found. Lignitic coal is widely distributed n the region, but no extensive coal fields have been discovered. CLIMATE. GENERAL FEATURES. Abbe,^ in his very comprehensive discussion of climate in Alaska, divides Alaska into eight climatic provinces, whose pronounced cli- matic differences he ascribes to mountain ranges, the Japan current, and other physical features. He describes the interior province as comprising the central plateau region between the Rocky Mountain system on the north and the Pacific Mountain system on the south, thus including the Yukon-Tanana region at its very heart. The meager meteorologic records in the interior prior to 1903, summa- rized by Abbe, have been materially increased since that date, so that more definite conclusions regarding the climate may now be drawn. 1 Abbe, Cleveland, jr., U. S. Geol. Survey ProL Paper 45, pp. 133-200, 1906. GENERAL FEATURES. 19 TEMPERATURE. The Yukon-Tanana region is characterized by extreme ranges in temperature, both annual and monthly. The annual range is shown by the records to vary from 120° to 164°. The greatest extreme monthly ranges occur in January and February and frequently exceed 90°. The maximum temperatures reported at the stations range from 85° to 96° and the mmimum from -50° to -76°. The maximum, minimum, and mean monthly temperatures at Eagle from 1905 to 1912 and at Fairbanks from 1904 to 1912 are shown in the following tables: Monthly temperature at Eagle, 1905 to 1912. Maximum. Year. Jan. Feb. Mar. Apr. May. June. July. Aug. Sept. Oct. Nov. Dec. An- nual. 1905 \ 75 84 82 88 92 80 91 82 75 63 42 38 1906 51 40 54 64 34 i 1907 36 20 1908 80 76 78 81 77 68 67 76 79 67 50 45 48 61 58 35 22 30 39 38 25 t 1909 26 10 15 28 45 44 44 52 41 51 53 55 59 59 67 78 66 78 82 87 85 80 81 91 "'"84" 1910 34 1 1911 35 1 1912 36 1 The period. . 36 45 52 64 84 92 91 82 79 63 42 36 92 Minimum. 1905 25 23 21 23 • 16 17 20 16 33 39 34 31 29 24 26 24 40 29 20 - 8 - 8 -50 -39 -41 -52 -28 -30 -40 1906 -11 -42 -50 -27 -50 -54 -30 11 -32 -20 I?? -38 -55 -34 -52 1907 -53 -48 -69 -61 -62 -52 -31 -51 -63 -56 -31 31 32 33 29 '"'36" 27 27 23 20 24 20 19 2 12 11 10 12 -15 -21 - 8 - 2 10 - 2 1908 1909 1910 -53 -47 -50 1911 1912 The period . . -69 -63 -54 -38 16 21 29 20 2 -21 -52 -55 -69 Mean. 1905 47.4 58.2 49.8 56.8 67.7 57.2 64.8 60.6 42.6 29.6 14.4 1906 28.4 4.6 24.6 30.4 1907 - 9.8 -20.0 1908 52.3 52.1 50.6 51.5 50.6 36.4 38.0 43.6 42.2 42.9 18.3 20.7 26.2 34.0 28. 2 2.9 -11.0 1.2 .4 9.0 -2.1 1909 -40.2 -13.1 -31.3 -is. 4 -15.8 3.1 8.8 8.4 6.6 5.0 16.4 19.6 23.4 21.2 32.2 42.2 44.4 43.8 47.7 62.4 55.8 55.6 51.2 59.9 59.0 '"54."6 1910 —19.6 1911 — 4.6 1912 — 7. 4 . The period. . -23.6 - 8.5 11.6 25.2 47.6 58.1 59.6 53.0 41.0 26.5 2.8 -8.4 23.3 Monthly temperature at Fairbanks, 1904 to 1912. Maximum. Year. Jan. Feb. Mar. Apr. May. June. July. Aug. Sept. Oct. Nov. Dec. An- nual. 1904 62 59 70 63 64 74 78 80 64 52 53 58 42 51 49 49 67 53 28 40 37 38 46 29 25 35 29 23 33 30 20 33 43 32 28 1905 ■•. 20 13 34 32 25 28 20 29 60 58 64 55 54 56 54 60 72 81 80 74 74 76 59 76 ""84" 79 83 77 86 82 87 79 83 82 79 82 86 84 85 82 77 84 80 65 76 85 78 1906 21 """38" 14 35 43 40 46 35 36 43 44 39 47 1907 1908 1909 1910 1911 1912 The period.. 34 43 47 64 81 87 86 85 80 67 46 43 87 20 SUBFACE WATER SUPPLY OF YUKON-TANANA REGION, ALASKA. Monthly temperature at FairhanJcs, 1904 to 1912 — Continued. Minimum. Year, Jan. Feb. Mar. Apr. May. June. July. Aug. Sept. Oct. Nov. Dec. An. nual. 1904 17 18 13 20 15 11 12 22 28 - 7 - 8 2 -16 -21 -10 -15 11 -12 -35 -25 -50 -41 -30 -54 -30 -34 -29 -47 -47 -46 -36 -48 -42 -58 -45 1905 -48 -65 -58 -51 -54 -55 -62 -42 -12 -31 -19 - 8 -14 -32 3 24 27 26 30 26 24 26 26 *"4i" 37 35 35 35 31 31 30 40 38 40 42 36 36 40 29 32 36 31 19 30 28 31 1906 -38 "-32' -45 -57 -44 -32 -22 -48 -35 -21 -32 -56 -21 1907 1908 1909 1910 1911 1912 The period.. -65 -57 -56 -32 24 31 30 19 11 -21 -54 -58 -65 Mean. 1904 39.5 38.2 44.0 42.5 37.8 40.0 45.7 45.4 45.6 28.0 23.3 31.2 19.0 21.8 21.6 24.2 35.3 26.6 -10.6 12.6 .0 2.6 7.0 - .8 - 1.0 -2.7 1.9 -10.8 -13.4 -16.7 - 3.5 - .4 4.6 -12.8 -5.8 1905 -17.0 -36.6 - 3.3 -11.3 -26.2 -19.6 -23.8 - 4.4 36.6 25.5 30.2 26.0 24 22.3 17.4 38.2 47.2 49.4 49.8 48.6 47.1 48.8 42.8 51.6 60.4 57.2 58.2 57.2 57.5 57.2 53.9 52.0 60.4 59.6 59.9 60.8 61.2 64.5 60.9 54.8 55.6 55.4 54.3 44.0 54.1 46.4 55.2 1906 0.2 ""2.1 -10.5 -11.7 2.0 9.2 17.7 5.2 5.2 10.2 8.3 2.5 22.7 1907 1908 1909 1910 1911 1912 The period. . -17.8 1.4 10.3 27.5 48.2 54.7 61.4 52.5 42.1 25.7 1.0 -7.4 25.2 The long intensely cold winters of the interior have resulted in great depths of permanently frozen ground, some alluvial deposits having been reported to be frozen for more than 300 feet below the surface. Favorable conditions with respect to material and drainage have governed the distribution of frozen ground to some extent, however, and considerable areas are believed to be unfrozen. In the short, comparatively cool summers the depth to which the frozen ground is thawed does not often exceed 3 or 4 feet. In the winters ice 3 to 6 feet thick usually forms on the larger lakes and streams. Streams like the Yukon, which have an appreciable current, freeze in most places to a depth of 3 to 4 feet. At some rapids, however, as on the Yukon a short distance below Dawson, Yukon Territory, and on other streams, the water never freezes. Quiet bodies of water sometimes freeze to a depth of 6 feet. On the smaller streams ice formed in the channel frequently obstructs the water underneath and causes it to overflow the surface, where it freezes, thickening the mass greatly. These accumulations of ice, known as glaciers, often form in masses so great that they are not entirely thawed until far into the summer. In many places they seriously obstruct mining, and in others they favor it by prolonging and equalizing the stream flow. The freeze-up of the navigable streams has such an important economic effect upon commerce in Alaska that it has resulted in the general recognition of two seasons — the ''open,'' during which the Yukon is open to navigation, and the ''closed," during which the GENERAL FEATURES. 21 Yiikoii is either filled with floating ice or is frozen over. In the following tables are given records collected by agents of the Northern Commercial Co. on the break-up and freeze-up of Alaskan streams. The dates given show remarkable uniformity as compared with those of streams in more southern latitudes. In April and early in May the sun gradually becomes higher and its rays warmer until the accumulated snow and ice begin to melt. The tributary streams slowly increase their discharge into the large streams, raismg the ice sheet until it can no longer remain intact and breaks away from the shore. This parting of the ice from the shore, or the break-up, indicates that the open season is at hand and is a momentous event for the people of the interior. Once broken up, the ice starts on its way to the sea, attended by an almost unimagin- able spectacular display of tremendous forces. From bank to bank the huge moving ice cakes grind upon each other with an awe-inspiring exhibition of resistless force. At places the ice pack is obstructed, but sooner or later it forces its way past the obstacles and moves on, carrying away every movable thing in its path. When, after 7 to 12 days, the river is finally free, the ^'open season" has commenced and the river boats may venture from their winter quarters. The records show that on the Yukon the break-up usually occurs about May 12 and that navigation may start about May 20. The date of the freeze-up is not quite so uniform as that of the break-up, but it usually occurs near the last of October or the first of November. The ice commences running in the river, and with the increasing cold the mass grows in size until it solidifies in a com- plete sheet and becomes anchored to the shore. Thereafter the river is closed to navigation. Dates of break-up and freeze-up on Yukon River, its tributaries, and St. Michael Bay. [Furnished by the Northern Commercial Co.] Stations on Yukon River. Dawson. Eagle. Circle. Year. Break- up. Freeze- up. Break- up. Freeze- up. Break- up. Freeze- up. 1896 May 17 May 14 May 6 May 17 May 8 May 14 May 11 May 13 May 17 May 10 May 11 May 5 May 7 May 11 ... do . . Nov. 13 Nov. 8 Nov. 5 Oct. 23 Nov. 2 Nov. 12 Nov. 4 Nov. 9 Nov. 6 Oct. 10 Nov. 7 Nov. 2 Oct. 26 Nov. 11 Nov. 4 Nov. 8 ...do 1897 1898 May 10 May 16 May 8 May 12 May 15 May 14 May 6 May 9 ...do May 3 May 7 May 10 ...do May 6 May 3 Nov. 8 Nov. 2 Nov. 13 Nov. 15 Nov. 19 Nov. 13 Nov. 14 Oct. 19 Nov. 14 Nov. 4 Oct. 29 Nov. 22 Nov. 8 Nov. 15 Nov. 16 1899 1900 1901 May 22 May 16 ...do.... May 17 May 16 May 14 May 8 May 13 May 12 May 15 May 12 May 15 Oct. 15 1902 Nov. 5 1903 Oct. 21 1904 Nov. 3 1905 Oct. 23 1906 Nov. 8 1907 Oct. 18 1908 Oct. 23 1909 Oct. 2 1910 Oct. 29 1911 May 7 May 9 Nov. 2 1912 Oct. 26 22 SURFACE WATER SUPPLY OF YUKON-TANANA REGIOK, ALASKA. Dates of break-up and freeze-up on Yukon River, its tributaries, and St. Michael Bay — Con. stations on Yukon River — Continued. Rampart. Fort Gibbon. Andreafski. Year. Break- up. Freeze- up. Break- up. Freeze- up. Break- up. Freeze- up. 1896 1897 1898 May 22 May 19 May 15 May 24 May 21 May 19 May 11 May 16 May 13 May 10 May 14 May 17 May 18 Oct. 15 Nov. 6 Nov. 3 Nov. 8 Nov. 9 Oct. 24 Nov. 11 Oct. 29 Nov. 10 Nov. 2 Oct. 29 Nov. 6 ...do 1899 1900 May 8 May 24 May 13 May 22 May 7 May 12 May 16 May 6 May 22 ...do Oct. 30 Nov. 3 Nov. 7 Oct. 21 Nov. 4 Oct. 26 Nov. 9 Oct. 27 Oct. 26 Nov. 3 Nov. 4 Nov. 8 Nov. 4 1901 1902 • 1903 1904 1905 1906 . .. 1907 May 19 May 22 May 18 May 28 Oct. 9 1908 Oct. 23 1909 Oct. 6 1910 Oct. 22 1911 May 11 May 3 Nov. 8 1912 Stations on tributary streams of the Yukon. Fiftymile River at White- horse, Yukon Territory. Lake Lebarge, Yukon Territory opened. Tanana River at Fairbanks. Koyukuk River at Settles. Year. Break- up. First boat left for Dawson. Last boat left for Dawson. Break- up. Freeze- up. Break- up. Freeze- up. 1899 June 5 May 28 June 9 May 29 June 12 June 6 May 26 June 2 June 5 1900 June 8 Jime 9 May 30 June 12 June 6 June 1 ...do.... June 5 Oct. 10 ...do.... Oct. 17 Oct. 11 ...do Oct. 9 Oct. 11 Oct. 12 1901 Apr. 21 ...do. .. . May 28 May 18 May 27 May 13 May 20 May 12 ...do ...do...- May 14 May 21 May 9 May 12 Oct. 7 1902 Oct. 22 1903 May 2 Apr. 25 Apr. 18 Apr. 25 May 2 May 7 May 3 May 8 May 1 Apr. 30 May 3 May 9 May 10 May 6 Nov. 13 Oct. 27 Oct. 14 Oct. 6 1904 Oct. 4 1905 Oct. 6 1906 Oct. 18 1907 Oct. 16 Oct. 20 Oct. 10 Oct. 7 1908 Oct. 3 1909 Sept. 29 Oct. 4 1910 June 8 June 7 1911 Nov. 4 Oct. 18 1912 Oct. 19 St. Michael Bay. Year. Break- up. Freeze- up. Year. Break- up. Freeze- up. 1875.... May 25 June 8 June 13 June 15 June 9 Jime 27 June 11 Jime 9 June 8 Jime 10 May 30 June 5 June 14 June 8 June 23 June 6 June 9 June 11 June 10 Nov. 20 Nov. 6 Nov. 15 Nov. 16 Nov. 9 Dec. 6 Dec. 7 Nov. 25 Nov. 21 Oct. 10 Nov. 5 Nov. 13 Nov. 2 Nov. 18 Nov. 16 Nov. 11 Nov. 14 Nov. 7 Nov. 5 1894 June 23 June 18 June 25 June 23 June 13 Jime 10 Jime 8 July 3 June 5 June 18 June 20 May 31 June 7 June 6 June 8 June 13 June 16 June 14 June 19 Nov. 1 1876 1895 Dec. 7 1877 1896 Nov. 21 1878 1897 Oct. 25 1879 1898 Oct. 31 1880 1899 Nov. 7 1881 1900 Nov. 22 1882 1901 Nov. 2 1883 1902 Do. 1884 1903 Nov. 1 1885 1904 Do. 1886 1905 Nov. 4 1887 1906 Nov. 9 1888 1907 Oct. 31 1889 1908 Nov, 1 1890 1909 Nov. 4 1891 1910 Nov. 7 1892 1911 Nov. 16 1893 1912 Nov. 7 GENEEAL FEATURES. 23 PRECIPITATlOlSr. Study of the stream-flow and rainfall data of the Yukon-Tanana region shows that they have an exceptionally direct relationship. Tlierefore, since a large and well-equaHzed water supply is of very great economic value to the mining industry in this region, the quan- tity and distribution of the rainfall has great significance, and any study of the run-off of this region would be very incomplete without a careful consideration of the precipitation. Precipitation stations which have been established for longer or shorter periods in the Yukon-Tanana region, Yukon Territory, and British Columbia are listed on page 24, with their latitudes, longi- tudes, and approximate elevations. The stations in Alaska have been maintained by or in cooperation with the Weather Bureau, and those in Canada have been maintained by the Canadian meteoro- logic service. The longest record in the Yukon-Tanana region has been kept at Eagle, where observations are available for 8 complete years and for 65 discontmuous months. Dawson has a continuous record for 11 years and 7 months and Fort Gibbon a very broken record which includes 4 complete years and 91 discontinuous months. The lengths of the different records decrease from those above men- tioned to ones extending over but two or three months. The following tables show the daily precipitation at Eagle and Fairbanks from 1906 to 1912. They also show, for shorter periods, the precipitation at stations which are closer to the mining regions and which it is believed portray conditions in these localities more accurately. In the winter records where snowfall was not reduced to melted snow by the observer, the equivalent rainfall has usually been assumed as one-tenth of the snowfall. The more complete records show that precipitation occurred on 120 to 140 days in the year and that over half of it fell in the summer. The rains in the regioa, however, are not excessive, and few of them exceed 1 inch in a 24-hour period; in fact, they are notable for being but slight showeis with a mere trace of precipitation. Sometimes these showers occur almost daily and yet are not sufficient to replenish the flow of the steadily f alMng streams. During the winter months snow ordinarily accumulates to a depth of about 3 feet. With the advent of the warm days of April and May it melts, usually causing high stages on the streams in the later part of May. On the northern slopes of the mountains, where the snow is protected from the rays of the low-hanging sun, it remains in patches until far into the summer. The tables give the monthly precipitation, in inches, at all stations maintained in the Yukon-Tanana region from 1903 to 1912. The same data are given for stations in Yukon Territory from 1901 to 1912. The scattered records prior to 1903 have been compiled by Abbe. 24 STJKFACE WATER SUPPLY OF YUKOK-TANANA REGION, ALASKA. On page 39 is given a table summarizing the mean monthly precipi- tation at stations in the Yukon-Tanana region and Yukon Territory where records have contiaued over 24 months. The table also shows the length of the record and the mean yearly precipitation for each station. The average mean monthly precipitation at seven Weather Bureau stations in the Yukon-Tanana region and the fluctuation of annual rainfall at some of these stations are shown graphically in figures 3 and 2 (pp. 41 and 40), respectively. Precipitation stations in Yukon- Tanana region. Station. Index letter on PL IV. Latitude. lyongitude. Approxi- mate elevation above sea level.o Central A o / 65 33 65 50 65 23 64 05 65 05 64 55 64 40 64 45 65 27 64 50 65 17 65 12 64 58 64 07 65 32 64 30 65 08 65 30 65 02 63 24 o / 145 49 144 04 146 16 141 56 147 26 141 40 141 19 141 10 145 28 147 44 146 23 152 00 150 40 142 20 145 14 142 10 147 2S 150 15 147 26 143 24 Feet. 950 Circle B 500 Charity Creek C 2,800 Chicken Creek T). 1,400 Clearv E... 1,000 Crooked Creek F... . 1,000 Discovery Fork 1,500 Eagle II 850 Easle Creek I.. 2,600 Fairban ks J 450 Faith Creek K 1,400 Fort Gibbon L... 300 Hot Sprines M 350 Kef^humstuk N. . 2,000 Miller House 0.. 1,700 North Fork P 1,400 750 Poker Creek Q R ampart R 350 Summit House S 2,300 Tanana Crossing T... 1,450 a The elevations are estimated from the available topographic maps, which are based on a datum deter- mined by barometer. They may therefore be considerably in error but probably show the relative elevations of stations with suflRcient accuracy. Precipitation stations in Yukon Territory and British Columbia. Station. Latitude. Longitude. Approxi- mate elevation. Atlin, British Columbia Dawson, Yiikon Territory Whitehorse, Yukon Territory 59 45 64 05 60 46 133 46 139 28 135 00 Feet. 2,800 1,100 2,150 GENERAL FEATURES. Daily precipitation, in inches, at Eagle, 1906-1912. 25 Day. Jan. Feb. Mar. Apr. May. June. July. Aug. Sept. Oct. Nov. Dec. 1906. 1 0.10 .12 .02 0.11 0.03 Tr. Tr. Tr. 2! :::::::::: 0.01 3 0.49 0.07 4 .04 5 .03 .04 6 .03 Tr. 7 8 0.01 9 .07 .11 10 . . . .09 .78 11 .34 .02 12 .02 .12 .02 Tr. 13 Tr. .08 1.10 0.14 .01 15 .16 .02 .40 16 .36 .03 17 .20 18 19 .16 0.27 20 21 .07 .03 22 .02 23 .09 .03 .15 .11 .18 .28 24 25 .20 26 .14 27 .04 .02 .10 0.07 28 1.00 .30 .38 .38 29 .10 .20 30 .02 31 .06 1 ' 1 .14 2.19 • 54 .51 2.54 1.28 .01 1.71 .57 .07 1907. 1 .46 .12 3 .28 .20 Tr. Tr. 6 .16 .45 .04 .10 6 """."63" .10 7 .28 .07 8 Tr. 0.07 9 Tr. .08 .05 10 . ... 11 .12 12 .77 .61 .23 .25 13 .10 .10 Tr. .24 .10 .24 .79 15 .16 .80 .08 .13 16 17 0.25 .11 .05 .06 .70 18 .48 .04 .04 .01 .18 .30 19 Tr. 20 .16 21 .03 Tr. 22 .26 23 .04 24 .18 25 26 .18 "".lY .08 .05 27 28 .08 .03 .05 29 .05 .04 .04 30 31 .02 1.45 .20 .25 .40 1.89 1.48 1.98 1.45 1.12 .40 .31 26 SURFACE WATER SUPPLY OP Daily precipitation, in inches, at YUKOK-TAl^AKA REGION, ALASKA. Eagle, 1906-1912— Continued. Day. Jan. Feb. Mar. Apr. May. June. July. Aug. Sept. Oct. Nov. Dec. 1908. 1 0.15 0.15 2 3 .38 4 0.05 5 0.40 .08 6 .18 0.18 7 0.29 8 .45 .05 9 10 .21 11 .10 .32 12 .45 .20 13 .16 14 0.01 15 .17 16 0.10 .05 17 .10 .05 0.09 .06 .16 18 .90 .19 19 0.75 20 .75 .15 21 .40 .10 .08 22 23 .80 .03 24 .12 25 „X)7 0.10 26 .05 27 .30 .53 .09 .20 '28 0.25 .05 .60 .22. 29 .03 30 31 .03 .12 .25 .75 .10 1.02 2.16 2.47 1.02 1.48 .18 .82 1.09 1909. 1 .14 .04 .05 .05 .10 """.'65' 2 3 Tr. 4 .23 Tr. .01 5 .12 .08 6 7 .24 Tr. g 9 .34 10 .08 .10 .23 .07 .6i 11 12 .04 .19 .17 .07 .03 .02 Tr. .09 13 .07 Tr. .06 .05 14 .11 .06 .06 .05 .02 .03 .01 15 1.00 16 .06 .04 17 18 19 .07 .47 ....... .06 .12 .21 .04 .05 "Tr'.' .05 20.. .53 21 .08 .08 .09 22 . .17 .02 23 24 .27 25. Tr. Tr. .04 26 .08 27 . .48 .16 28... .16 29 30 .16 .01 31.. . . .10 .04 .16 .07 .11 .34 .28 2.35 1.77 .95 .88 .28, .40 .23 GENERAL FEATURES. Daily precipitation, in inches, at Eagle, 1906-1912 — -Continued. 27 Day. Jan. Feb. Mar. Apr. May. June. July. Aug. Sept. Oct. Nov. Dec. 1910. 1 Tr. Tr. Tr. Tr. '"6.' 45' Tr. "'Tr'.' 0.13 .96 .04 Tr. .05 0.21 .01 Tr. 2 3 0.02 Tr. Tr. Tr. Tr. Tr. 0.24 .03 .05 ■' Tr.' 4 .02 Tr. .01 Tr. 0.04 5 Tr. 0.01 .33 .04 6 7 Tr. .04 0.02 1.24 .33 .04 8 9 0.04 .01 .10 .14 10 Tr. Tr. .01 .07 .03 11 .01 12 .78 13 .04 Tr. Tr. .06 Tr. .16 .06 .04 0.05 .06 14 .25 .44 Tr. .29 .08 Tr. 15 0.08 .07 .05 .13 .29 .07 "'Tr'.' .05 .13 .15 .20 .03 .13 Tr. .44 .02 .22 .04 .03 Tr. 16 .01 .05 Tr. .20 .02 17 Tr. 18 Tr. 19 Tr. 20 .10 .03 Tr. .10 21 Tr. .09 .02 .06 Tr. Tr. .01 .04 Tr. .25 Tr. .05 22 23 0.01 .03 Tr. .07 .14 .02 .06 Tr. .02 Tr. .04 24 Tr. .01 .33 .04 Tr. Tr. .15 Tr. Tr. 25 26 Tr. .10 27 .08 Tr. .27 Tr. 28 .18 "*T'r." Tr. .18 Tr. Tr. Tr. Tr. Tr. 29 30 .04 .12 31 Tr. .83 .01 .53 .25 .28 1.05 2.28 2.63 2.98 .69 .25 .30 1911. 1 .13 .04 Tr. .01 .04 .02 .06 .18 Tr. Tr. 2 .24 3 .30 .32 .10 Tr. .01 Tr. Tr. .08 "".'63" .06 .07 .06 Tr. .01 .03 Tr. .03 .05 4 .02 Tr. Tr. .01 Tr. Tr. 5 " Tr." .44 .04 Tr. 6 Tr. 7 8 .06 9 .17 .34 .06 "'.'62' .04 .06 .32 10 Tr. .02 Tr. Tr. .32 .24 .01 .14 .02 .30 .10 .33 Tr. .04 .49 .32 11 Tr. .05 12 .04 13 .19 .05 14 Tr. .06 15 Tr. .07 16 Tr. Tr. .03 .04 .02 .01 .06 17 .06 Tr. .07 Tr. .02 Tr. 18 Tr. .65 .07 .02 .06 19 Tr. 20 .05 .11 21 .08 22 Tr. .02 Tr. Tr. Tr. .01 23 .07 .02 .06 .10 .03 .08 Tr. .06 .01 .02 .04 24 Tr. 25 Tr. .04 Tr. 26 .02 27 Tr. .03 Tr. .58 .02 28 .01 .08 .02 29 .06 Tr. Tr. .86 .48 30 31 .53 .27 .39 .97 2.87 1.26 2.65 1.21 .13 .29 .80 28 SURFACE WATEE SUPPLY OP YUKON-TAKAI^A REGION, ALASKA.. Daily precipitation, in inches, at Eagle, 1906-1912 — Continued. Day. Jan. Feb. Mar. Apr. May. June. July. Aug. Sept. Oct. Nov. Dec. 1912. 1 Tr. 0.06 .44 .05 ""6."i6" 0.05 "6' 08' Tr. .12 "".'os' 0.06 2 0.11 3 Tr. Tr. Tr. 4 .03 .03 .13 .93 Tr. .06 .02 Tr. .05 5 0.01 Tr. 0.06 .06 .04 Tr. .04 6 .08 7 .06 .06 .13 .13 8 9 0.01 Tr. .14 .30 .04 10 .14 .44 .17 .04 .21 .92 .07 11 .01 "".'62' .02 Tr. .43 .05 12 .02 .47 13 14 .15 Tr. Tr. .10 .04 .06 .10 .05 Tr. 15 16 .09 .04 .05 .07 .01 .02 .01 17 .13 .04 .02 .35 .65 Tr. Tr. .06 .03 Tr. 18 .14 .04 .30 .01 .06 .12 .02 19 20 .11 21 .23 22 Tr. Tr. .04 .04 .22 Tr. . . . . 0.12 .12 Tr. .13 23 .06 24 .10 .03 Tr. .02 25 .02 .01 .05 .02 .01 26 .35 Tr. .02 27 Tr. .08 .18 Tr. .02 .04 .01 28 .09 29 .01 .02 30 Tr. Tr. 31 Tr. .06 .29 .11 Tr. .43 2.09 2.92 2.48 .76 1.66 .24 1.10 Daily precipitation, in inches, at Fairbanks, 1906-1912. Day. Jan. Feb. Mar. Apr. May. June. July. Aug. Sept. Oct. Nov. Dec. 1906. 1 0.04 .01 2 Tr. 0.40 • ... Tr. 0.11 0.03 " Tr".' Tr. Tr. Tr. Tr. Tr. 3 0.30 .02 Tr. .02 4 0.02 0.05 .03 Tr. .13 .05 "'.'22' .05 .10 .10 .04 .01 "'.'6i" 5 6 7 Tr. 0.33 .01 .06 .06 8 .10 Tr. 9 Tr. 0.04 10 .10 11 .10 .12 12 .02 .01 .10 .03 .09 13 .10 .15 .02 .15 .02 14 .10 .75 .20 "".'42' .09 .47 15 16 .03 '"".'i3* .01 17 .25 .02 18 .03 19 0.15 .05 0.20 20 .05 21 .05 Tr. .02 .13 .01 .05 .20 22 .03 .05 23 .05 24 .04 .02 .29 ....... 25 0.08 Tr. Tr. Tr. Tr. .05 Tr. .05 26 .62 .15 .31 .43 .04 .13 .40 .05 .40 27 .05 .08 .10 28 .04 .02 Tr. 29.. Tr. 30 .12 .01 .20 31 .05 1.71 .37 .13 .50 .36 .94 2.82 1.50 .25 .30 .65 1.15 GENERAL FEATURES. Daily precipitation, in inches, at Fairbanks, 1906-1912 — Continued. 29 Day. Jan, Feb. Mar. Apr. May. June. July. Aug. Sept. Oct. Nov. Dec. 1907. 1 0.05 .22 .16 .35 .35 .04 0.72 .01 0.02 0.05 2 0.05 3 0.04 .02 .03 4 .04 Tr. 0.18 .03 Tr. Tr. .10 .20 .05 .09 .23 .50 .25 0.05 .1 . .. 0.15 .09 .11 .07 Tr. .35 .01 Tr. .13 .12 ft Tr. 7 Tr. fi .36 .75 .01 .18 .02 .05 .23 .71 Q .04 0.15 .25 10 .15 .05 Tr. Tr. Tr. .02 .18 .10 .02 Tr. Tr. Tr. Tr. .02 .05 Tr. .25 11 .20 .17 .40 .17 .05 .30 .10 12 .06 13 .06 .05 Tr. .20 .30 .05 .03 15 0.03 .01 .19 Tr. .09 Tr. .14 '".'6i' .09 ,22 .27 ifi 18 .80 .40 .10 .12 .20 .02 20 Tr. .05 Tr. .18 .12 Tr. .15 .15 .16 .37 .01 21 - -- .02 22 .02 23 .20 .05 Tr. .05 .25 .18 .05 25 .20 26 Tr. .23 .30 .12 28 .30 .47 .13 .01 '"'.'i2" .13 .35 .50 30 3.30 2.42 .03 .35 1.47 1.51 1.81 3.58 2.44 .35 .59 1 .18 " Tr".' "".'ie' .12 .01 .11 .20 .02 .21 .09 .63 .12 .03 .01 .02 .02 3 4 ::::::.:..-- .50 .10 5 .05 .05 6 .06 .06 .23 .01 ""."io" .02 Tr. .07 Tr. Tr. '"'69" Tr. .06 .11 8 0.05 .20 9 .02 10 11 .02 Tr. .18 Tr. .13 .02 .15 Tr. " Tr.' .03 .16 .05 13 Tr. Tr. Tr. Tr. .02 Tr. .02 .04 .03 .17 .03 15 .01 Tr. Tr. .33 .02 16 .04 '"".04 .46 .05 .04 18 .05 .12 .03 .04 .01 19 .08 .03 .04 20 21 .21 Tr. .02 .12 .22 23 Tr. Tr. .02 Tr. .15 .03 .08 .02 .01 .03 '""."io' .03 .20 Tr. Tr. .08 .03 .01 .03 25 26 .02 .01 Tr. .01 Tr. .11 Tr. Tr. 28 .04 .01 Tr. 29 Tr. Tr. "".QQ 30 .42 .21 1.10 .11 .52 .96 .73 .71 1.53 .47 .51 .65 30 SURFACE WATER SUPPLY OF YUKON-TANAITA REGIOK, ALASKA. Daily precipitation, in inches, at Fairbanks, 1906-1912 — Continued. Day. Jan. Feb. Mar. Apr. May. June. July. Aug. Sept. Oct. Nov. Dec. 1909. 1 Tr. " Tr.' 0.20 .10 '" Tr'.' Tr. 2 0.02 0.12 Tr. 0.03 0.06 0.20 3 .10 4 0.02 5 Tr. 6 .10 .01 7 0.65 .01 .14 Tr. .29 .12 .01 8 9 .01 10 .01 .01 .15 11 0.32 .25 '"".'07' .15 Tr. .12 Tr. Tr. 12 .01 .09 .15 .04 .20 13 .15 .01 .01 14 0.10 .10 .20 15 .01 16 .06 17 18 .11 Tr. 19 20 .12 21 Tr. Tr. .03 Tr. Tr. .50 22 Tr. .03 23 .10 .93 .02 .08 .15 .72 .13 Tr. 24 25 0.08 26 .07 .05 .13 .01 .01 .04 .07 .05 Tr. Tr. 27 28 .06 29 .09 .06 30 31 Tr. Tr. .90 .08 .05 .66 .38 1.64 1.90 1.73 .39 .75 .52 .80 1910. 1 .11 Tr. 2 3 .05 Tr. .06 Tr. 4 Tr. 5 .38 Tr. Tr. 6 Tr. Tr. Tr. .60 7 .22 Tr. .35 .01 Tr. 8. 9 Tr. 1.45 .05 10 11 Tr. Tr. 12 .14 13. Tr. Tr. .20 14 .10 .18 .55 .36 .12 .36 .03 Tr. 15... 16 Tr. Tr. Tr. 0.20 .21 .75 .10 .17 Tr. Tr. 17 18 Tr. 19 .11 Tr. .15 Tr. Tr. .09 Tr. 20... .01 Tr. .12 Tr. 21 Tr. .45 Tr. Tr. 22 .15 .16 23 Tr. Tr. .26 .23 .22 .01 Tr. Tr. Tr. 24 25... 26 Tr. .60 Tr. Tr. Tr. .05 27 Tr. 28 .08 29. 30 .01 .11 31.. ■ .27 .70 .14 .02 .36 .39 2.16 .46 1.69 1.91 .66 .58 .76 GENEKAL FEATURES. 31 Daily precipitation, in inches, at Fairbanks, 1906-1912 — Continued. Day. Jan. Feb. Mar. Apr. May. June. July. Aug. Sept. Oct. Nov. Dec. 1911. 1 Tr. 0.40 Tr. 0.28 0.51 .05 2 0.50 0.15 3 1.05 Tr. 0.19 .05 4 .40 .18 5 Tr. .20 6 Tr. 7 I .12 .24 O.IS .09 .03 8 Tr. 9 Tr. .25 Tr. 0.06 Tr. Tr. .02 .10 .06 .09 10 .75 .07 .10 11 .40 .03 12 ' 0.08 .04 13 .20 .13 .61 .40 .04 .01 20 14 .10 .02 15 .05 16 .08 Tr. .25 .06 17 .10 18 Tr. Tr. Tr. Tr. Tr. Tr. 20 .11 21 .08 .06 22 .06 23 .12 .23 .12 .12 .11 .02 .09 .07 24 .03 25 .04 26 .30 .03 .17 .01 .02 Tr. .02 Tr. .02 Tr. .50 . Tr. Tr. Tr. .02 28 .35 .13 Tr. .01 30 31 1.50 .62 .06 1.55 2.16 2.30 1.60 .22 .49 1.23 1912. 1 0.25 .15 .05 .12 .14 .07 .10 .01 Tr. 2 .05 3 .07 .06 .11 Tr. 5 .05 .05 .16 .03 .06 .06 .22 1 6 .02 1 7 Tr. 8 1 9 .03 Tr. 1 10 .30 .01 11 .02 "".m .02 .01 .05 13 .04 .20 .03 Tr. 15 .13 .20 .03 .09 .43 Tr. Tr. .09 16 .66 .01 .19 .07 .06 .24 .02 .01 "".'oi" .07 .02 Tr. Tr. .01 " Tr'.' .08 Tr. .02 .08 Tr. .15 .16 .09 .05 .02 .13 Tr. .12 .08 18 19 .05 .10 .05 1 20 1 21 .02 .03 .02 .17 .32 .22 .01 .84 .15 .06 i 23 24 .03 25 26 .09 . 27 ...__ Tr. .15 28 .50 29 Tr. Tr. Tr. .26 30 .08 31 .12 .10 .10 .95 1.22 3.15 .96 .82 1.16 .54 .24 32 SUKFACE WATER SUPPLY OF YUKON-TANANA EEGIOK, ALASKA. Daily precipitation, in inches, at Poker Creeh, 1907-1909. Day. Aug. Sept. Oct. Nov. Dec. Day. Aug. Sept. Oct. Nov. Dec. 1907. 1 1907. 16 17 18 19 0.01 .01 .07 0.10 2 " 'Tr'.' 0.15 .30 .20 Tr. 3 4 0.10 Tr. 0.05 .30 .10 0.08 0.13 5 20 .40 .13 .27 .15 6 . -. 0.05 .24 "".'6i' .02 .01 Tr. .63 .88 21 22 23. 24 25 26 .13 .02 .13 .04 .15 7 . . 0.05 8 .05 9 .33 .05 .17 .30 .20 .10 .10 10 11 .03 .10 12 27 .04 13 .18 28 29 30 .02 .15 '"".'36' .20 .15 14 0.04 1*^ 70 Tr. 31 1.40 3.70 1.70 .25 1.07 Day. Feb. Mar. Apr. May. June. July. Aug. Sept. Oct. Nov. Dec. 1908. 1 0.04 .03 0.02 """6.'62' .06 .33 .01 .12 0.11 .40 0.10 .12 0.40 .32 .30 .02 2 3 4 5 Tr. Tr. 6 .10 .16 .71 '""'64' Tr. ""'."63" .04 7 0.08 8 0.38 9 .03 .04 Tr. .02 .08 10 .03 .13 .13 .06 .23 11 .04 .05 .05 .08 .12 .06 """6*63' .04 12 .11 13 Tr. 14 Tr. .30 .07 .07 .01 '"".08 .15 .04 15 Tr. 16 .12 """.'63' Tr. .16 1.00 .05 17 .47 .02 .05 """.'32" .28 18 Tr. 19 .02 20 0.06 Tr. 21 .02 Tr. Tr. .12 .03 Tr. .08 .05 22 23 Tr. .04 Tr. .09 24 Tr. .35 Tr. 25 26 .12 .80 .34 .04 27 .02 ""'Tr'" 28 .10 .18 .05 .04 .18 29 30 31 .62 1.32 .42 .58 1.80 2.02 .99 2.45 .75 .35 .61 GENEEAL FEATURES. 33 Daily precipitation, in i nches, < It Poker Creek , 1907- 1909— Continued. Pay. Jan. Feb. Mar. Apr. May. June. •Tuly. Aug. 1 1909. Tr. Tr. 0.18 .06 0.21 2 0.06 .20 3 Tr. 4 Tr. 5 .28 6 Tr. .15 .02 '"'6.' 64" Tr. Tr. .24 .08 .10 7 0.20 8 .24 9 .59 10 .... .38 .08 .03 11 0.21 .27 .02 12 .10 Tr. .22 13 U .17 15 .10 .11 16 0.02 Tr. 18 .24 .07 20 .05 Tr. Tr. .20 .13 22 Tr. 0.03 """."63' """"."75" 23 24 .02 .05 Tr. .20 .08 .07 25 Tr. Tr. .04 .06 .25 26 .14 28 Tr. .12 30 .08 .68 .09 .03 .42 1.11 1.22 2.01 2.01 Daily precipitation, in inches, at Cleary, Faith Creek, and Summit Roadhouse, 1907. Day. Cleary. Faith Creek. Summit Road- house. June. July. Aug. Sept. July. Aug. July. Aug. 1 1.17 .12 0.49 .19 1.27 2 0.02 .06 3 0.09 4 .09 0.08 .14 '""'.'64" .20 .03 .11 .15 .15 .10 .02 5 6 .04 .22 "'".'46' .08 0.30 .06 """"."so" .12 .22 .27 7 .30 .09 .12 .11 .22 .14 ""'"."63" .14 .07 8 .42 9 .11 10 .47 .09 .32 11 12 .21 .80 13 .03 .05 .28 .11 .01 .35 .01 """".'67" .04 '"*"."6i" 14 .30 .05 .24 .03 .24 .13 15 .19 .20 .01 .15 .85 16 17 .09 IS .05 19 20 .15 .13 21 .19 22 .10 .11 .09 .13 .52 .23 .13 .04 23 .20 24 .27 .23 .15 .36 .03 .22 .15 .02 .13 25 .03 26 .12 .07 .31 27 0.01 .41 .42 28 .09 .54 .13 "'"."is" .26 29 .06 .12 .22 .13 30 .39 31 a. 84 2.55 2.88 3.82 1.87 3.00 2.71 3.27 42913° — wsp 342—15- a June 25-30. 34 SUKFACE WATER SUPPLY OF YUKON-TANAITA REGION, ALASKA. Daily precipitation, in inches, at Charity Creek, 1908. Day. Apr. May. June. July. Aug. Sept. Oct. 1 0.01 0.20 "'6.' is' .02 0.03 .10 .01 0.37 .20 .44 .05 2 3 Tr. Tr. .25 .10 .08 4 5 .17 .29 .40 .28 6 ""t'r'.' .35 .10 .07 .04 0.08 7 8 Tr. 9 .03 .02 .01 10 Tr. Tr. .11 .01 .31 .05 .05 Tr. .04 Tr. Tr. .04 .02 .31 .32 11 Tr. 12 .05 13 .05 .05 14 .08 .27 '"'Tr'.' '"'Tr'.' .10 .02 .06 .34 .07 .20 .20 .20 .05 .01 .19 15 16 .06 .08 .38 .30 .01 17 18 19 .01 20 21 22 Tr. .18 .01 23 24 25 0.08 26 Tr. .28 .15 .15 27 .03 .02 .13 .03 '"".'06* "".'25' .03 28 29 30 31 o.ll .27 1.33 2.80 2.33 2.28 .20 a 33 inches of snow on ground at end of April. Daily precipitation, in inches, at Miller House, 1909, 1910, and 1911. Day. 1909 1910 1911 Sept. Oct. Nov. Dec. Jime. Jiiiy. Aug. Sept. June. July. Aug. 1 0.63 2 0.10 .20 0.04 0.93 3 4 .48 5 0.59 0.43 6 7 g 0.10 .12 .05 9 - . .. .05 10 11 12 0.20 13 14 . 0.08 15 .60 .10 16 0.30 .02 .04 .05 17 0.24 .10 18 1.00 19 20 .10 .10 .15 .02 21 .23 .15 22 .20 23 1 .06 24 25 .15 26 .14 27 28 .77 .30 .08 .31 .15 29 ""."26' .44 30 31 .10 .06 .60 .93 .30 .30 1.94 2.37 .30 1.03 1.80 1.41 .18 GENEKAL FEATURES. 35 Daily precipitation, in inches, at Chicken Creek, 1911-12. Day. June. July. Aug. Sept. Oct. Nov. Dec. 1911. 1 0.08 2 0.03 .12 0.05 3 0.15 .05 0.05 .18 .02 4 0.05 .20 .10 5 .15 .15 6 .10 7 .05 8 .02 9 10 .05 .20 0.05 .30 .25 11 .08 12 .08 13 .10 14 .25 .08 .03 .05 .18 16 .17 .05 .10 .05 18 20 .25 21 .08 23 .07 .05 24 .05 .10 .05 .17 .05 26 .. .05 .10 .08 28 .05 .10 .10 30 .10 .45 1.08 .68 1.02 .50 a. 45 a. 89 Day. Jan. Feb. Mar. Apr. May. June. July. Aug. Sept. 1912. 1 0.08 0.15 .15 2 0.15 3 .05 1 4 1 .10 5 1 6 0.20 .40 .01 7 8 ;::;:; .25 .05 9: 1 0.10 .05 0.20 10 0.05 .20 .90 11 12 13 ! .55 .03 .25 .35 .10 .03 14 .12 15::: 1 .16 16 17 .30 18 1 .02 .10 19 1 .40 20 .05 .10 .20 .20 .15 .10 21 .30 .08 22 .18 23 1 24 1 .30 .10 .12 .32 .25 .18 25 1 26 .03 27 28 .22 .30 29 30 .05 . . .• 30 31 a. 18 a. 80 1.02 2.38 .68 2.51 1.40 a One-tenth of snowfall. 36 SURFACE WATER SUPPLY OF YUKOIT-TANAITA REGION, ALASKA. Daily precipitation, in inches, at Crooked Creeh, 1911 and 1912. Day. 1911 1912 July. Aug. Sept. May. June. July. Aug. Sept. Oct. 1 0.13 .03 0.04 .42 '"6." 35' 0.91 .12 .05 '"6 ."62' .13 0.31 2 '"q.m 0.06 .03 3 4 5 .10 .33 .04 0.02 .02 6 .22 1.20 .01 ^ .13 .14 .14 8 .30 .15 .04 .07 9 .18 10 . .20 .25 .33 .12 .91 .02 .38 11 .52 .14 12 .58 .04 .14 13 .. .05 .19 .16 .03 .60 .05 .20 .12 .02 .04 .15 .22 14 .. y 15... . .15 .02 .05 16 . ...1 17 . ..1 .10 .26 .05 .18 .05 .47 .03 is . . : 1 .15 .01 .05 .03 20 1 21 .84 .05 .10 .03 .03 .20 .10 .35 1.30 """.■75' .05 .20 .03 23 . 24 .09 .03 .44 .10 26 ""."62" .38 .05 .03 .33 .40 28 : .03 .60 .02 .02 .11 29 .10 30 .19 31 2.52 2.18 1.30 .93 2.25 4.37 4.73 .75 0.93 a Oct. 1-10. Daily precipitation, in inches, at Discovery Forh, 1911 and 1912. Day. 1911 1912 May. June. July. Aug. Sept. May. June. July. Aug. 1 0.10 Tr. 0.37 ""6." 25" 0.23 2 3 Tr. 0.19 Tr. Tr. Tr. 4 .05 Tr. Tr. 5 .06 6 0.07 .40 7 .01 .19 .26 .17 .16 .04 .35 8 Tr. .10 9 Tr. .10 .10 .18 10 .12 0.70 0.38 .30 .03 .08 11 Tr. .17 Tr. .15 .95 12 "".'67' .14 Tr. .15 Tr. .30 .15 .15 .10 Tr. .04 13 Tr. 14 Tr. .37 Tr. .12 .12 .04 .05 Tr. .15 .43 15 16 17 18 0.08 .50 .03 Tr. Tr. .28 19 Tr. Tr. .47 20 Tr. 21 .22 Tr. Tr. .33 .05 22 Tr. Tr. 23 Tr. .57 .23 Tr. .07 Tr. .12 .02 .03 24... . Tr. 25 26 .. 1 .56 .24 ■"".'27' .23 27 1 .27 .19 Tr. 28 .32 .04 ■■■Tr.' .05 Tr. .25 .25 29 .17 1.16 .47 30 .41 31 a 2. 41 1.24 2.36 2.23 1.15 .53 1.81 2.32 2.47 a May 17-31. GENERAL FEATURES. 37 Monthly precipitation, in inches, at stations in Yukon- Tanana region, 1903-1912. [Rainfall or melted snow is given in the first line; snowfall in the second line. Melted snow as a rule is taken as one-tenth of the snowfall.] Station. Year. Jan. Feb. Mar. Apr. May. June. July. Aug. Sept. Oct. Nov. Dec. An- nual. Central 1906{ 1907{ 1906{ 1907{ 1908| 1909/ 1908/ 1911 1912 1907 1911 1912 1911 1912 1903 1905 1906{ 1907{ 1908| 1909| 1910 1911 1912 1908 1904 1905| 1906| 1907/ 1908| 1909 1910 1911 1912 1907 1903 1904 1905 1906{ 1907/ 1908/ 1909/ 1910 1911 1912 1909/ 1910/ 1904 1905 1906/ 1907/ 1908/ 1909/ 0.56 6.1 1.04 10.0 0.06 1.0 .42 4.0 0.05 1.4 2.57 4.0 0.47 4.7 .93 8.0 0.86 2.0 .57 1.5 4.91 4.82 1.85 0.52 0.70 7.0 0.80 8.0 0.35 4.0 15.95 34.2 2.21 1.40 Do 1 .75 9.5 .63 8.2 1.11 11.2 Circle 1.02 8.5 1.23 9.2 .44 4.5 .57 7.8 .25 2.5 .47 5.2 .28 3.25 .76 6.8 .17 1.0 .15 .29 1.36 2.79 1.73 Do Do 1.45 8.0 .75 3.0 .11 .29 .20 .87 1.08 2.21 .40 3.0 .75 8.5 10.60 51.2 .60 2.24 3.25 1.02 Do Charity Creek. .27 1.33 2.80 2.33 2.28 .20 3.0 .50 Chicken Creek .45 2.38 .84 1.08 .68 2.55 2.52 4.37 2.36 2.32 2.40 1.52 2.54 .68 2.51 2.88 2.18 4.73 2.23 2.47 .97 2.72 1,28 1.02 1.40 3.82 1.30 .75 1.15 .45 .89 Do .18 .80 i.62 Cleary Crooked Creek Do .93 2.41 .53 1.38 .33 .54 2.25 1.24 1.81 .57 1.95 .51 a. 93 DiscoveryFork Do .12 Eagle b Do . . .58 .81 .54 2.97 3.38 .01 2.96 1.71 .46 1.12 13.0 .18 6.0 .28 11.7 .69 .13 1.66 .93 .51 8.5 .40 4.0 .82 7.0 .70 3.0 .25 .29 .24 .68 .07 1.0 .31 Do 'iaK 2.0 .12 3.0 .16 2.0 .83 .27 .14 1.0 .20 2.0 .25 2.5 .07 1.0 .01 .24 .29 2.19 11.0 .75 7.5 .11 1.0 .53 .39 .11 .00 Do .25 .15 .10 1.0 .34 2.0 .25 .97 Tr. .40 .55 1.02 1.89 1.48 1.98 1.45 10.93 Do 2.16 2.47 1.02 1.48 1.09 11.0 .23 11.46 38.0 Do .28 2.35 1.77 .95 .88 6.1 2.98 1.21 .76 7.82 Do Do Do Eagle Creek... Fairbanks .28 2.87 .43 1.05 1.26 2.09 2.28 2.36 2.52 2.63 2.65 2.48 2.99 .30 .80 1.10 12.08 13.44 1.10 1.20 12.0 .65 6.5 .35 3.5 .51 2.00 .60 5.1 1.15 11.5 .59 5.9 .65 8.1 .80 .76 1.23 .92 9.1 1.71 17.5 3.30 33.0 .42 4.2 .90 .70 1.50 .10 .50 5.0 .37 3.7 .86 8.6 .21 2.0 .08 .14 .80 .10 .05 .5 .13 3.3 2.42 24.2 1.10 11.0 .05 .02 .06 .95 .20 2.0 .50 1.0 .03 .3 .11 .8 .66 .36 .„... 2.63 .86 Do Do .36 .94 2.82 1.50 .25 .30 .6 2.44 24.4 .47 10.89 44.1 Do .35 1.47 1.51 1.81 3.58 18.71 99.9 Do .52 .96 .73 .71 1.53 7.92 26.2 Do Do Do Do . . .38 .39 .12 1.22 1.64 2.16 "3." is' 1.90 .46 2.16 .96 1.87 1.76 1.95 4.90 1.73 1.69 2.30 .82 3.00 "i'so' 3.02 .39 1.91 1.60 1.16 2.97 .48 .35 .59 .75 .66 .22 .54 .52 .58 .29 .24 9.80 9.83 Faith Creek... Fort Gibbon . . Do Do Do .37 .08 .37 .65 6.0 1.26 12.6 .23 4.0 .05 .5 1.23 .94 .08 .73 .55 .47 .20 2.0 ".'26' 6.0 .10 .5 .08 1.63 .65 1.14 .35 Tr. .30 3.0 .53 5.0 .90 17.0 .37 '".m .38 1.16 .23 .09 .32 Tr. .16 .22 .84 1.00 .38 .33 1.50 .22 .39 .50 6.50 C5.0 1.22 12.0 .45 6.0 .49 4.8 .38 .44 .87 .44 4.4 .33 .07 1.10 .99 9.9 .03 1.5 .08 ".'46' 4.6 ".'ie' .08 1.10 11.0 Tr. .70 .18 .27 2.7 .31 "8." 88 13.79 Do 6 .39 2.2 .28 .77 .02 .30 2.58 2.31 2.32 4.0 1.60 2.25 .90 Do 1.16 .96 1.13 .60 6.5 .80 8.0 .59 Do 1.51 .77 1.49 2.27 9.60 20.6 Do Do .69 1.53 1.18 .57 .27 2.06 1.79 1.41 1.59 1.76 2.26 2.19 3.24 3.19 .74 1.53 1.15 .25 Do .36 2.26 22.6 12.44 Hot Springs. . . 1.64 16.4 .03 .3 .60 6.0 .20 2.0 .34 3.4 1.80 .20 1.69 .76 d2.16 1.32 Do Kechumstuk. . .83 1.58 1.61 2.23 .40 3.25 .94 1.48 2.51 .64 2.16 .51 .30 1.18 .31 4.3 .72 9.0 . .03 .36 .29 .5 .40 4.0 .90 9.0 .23 .20 .20 3.0 Do Do .90 .36 4.0 .12 2.0 .10 .05 .5 .20 3.0 .30 .5 .05 .06 1.0 .27 4.0 .41 5.0 .10 1.0 .40 .27 5.0 Tr. ""."46' 4.0 .20 9.01 11.11 18.3 1.30 12.0 1.78 2.03 1.60 2.14 .49 2.0 1.35 Do Do 1.77 2.30 2.22 .20 2.0 3.66 3.39 Do a Oct. 1-10. b Records at Fort Egbert to June, 1909. c Oct. 7-31. d July 16-31. 38 SURFACE WATER SUPPLY OF YUKON-TANANA REGION", ALASKA. Monthly precipitation, in inches, at stations in Yukon-Tanana region, 1903-1912 — Continued. Station. Year. Jan. Feb. Mar. Apr. May. June. July. Aug. Sept. Oct. Nov. Dec. An- nual. 1909<( 1910 1911 1905 isos/ 1907{ 1908{ 1907{ 1908/ 1909| 1905 1906/ 1907{ 1908/ 1909/ 1910/ 1911 1912 1907 1904 1905 1906 2.98 1.26 .60 4.0 1.03 .93 8.0 .30 3.0 .30 3.0 Miller House.. Do . .20 1.94 .80 2.37 1,41 .30 .18 1.91 1.01 Do North Fork 1.86 .72 ".'42' 3.2 1.40 12.0 .50 .55 4.5 .20 2.0 .20 .38 4.5 Do .70 7.0 .69 15.5 .50 5.0 .50 5.0 .28 3.0 .10 1.0 .27 3.0 .80 8.0 Tr. 1.98 2.74 2.69 12.59 33.2 1.34 4.0 1.92 1.57 3.19 2.0 5.0 Do Do Tr. 1.40 3.70 1.70 24.0 .75 6.9 .25 3.3 .35 4.4 1.07 6.8 .61 12.6 Poker Creek. . . Do ".'68' 8.8 1.32 10.5 .09 2.0 ".'63' .5 .42 5.0 .42 8.0 .58 1.80 2.02 .99 2.45 4.5 1.11 2.5 1.22 2.01 2.01 Do Rampart 1.33 .15 1.99 1.86 2.19 2.40 1.70 .59 1.20 .61 1.43 .95 10.2 .55 6.3 .73 3.6 .35 3.6 .26 3.5 .21 .27 .33 .33 3.5 1.26 Do .63 7.2 1.17 12.0 1.08 11.5 .09 1.4 .84 11.1 1.05 .13 .08 2.0 .44 4.5 .52 6.9 .10 1.2 .08 .8 2.20 .45 .17 1.8 1.17 12.8 .81 8.1 .37 6.2 .36 4.7 .31 .81 .04 .5 .02 2.5 .58 .40 8.21 25.2 Do........ .44 1.64 2.29 3.38 2.52 .65 15.53 Do .82 1.38 1.13 .46 1.56 .39 5.1 1.14 14.4 .45 6.0 .57 1.21 1.14 16.8 1.99 20.2 .32 5.0 10.60 52.0 Do .51 5.6 .07 1.0 .75 .01 1.04 .85 2.01 1.41 .36 1.5 .43 10.22 54.1 Do .20 .98 .71 .62 5.32 32.1 Do .48 .86 .34 3.03 .43 .54 2.71 .78 .37 1.12 1.52 3.27 .89 2.95 .79 1.50 a8..33 1.06 Do Summit Road house .59 10.92 Tanana Cross- ing .76 .14 .15 1.40 .10 .60 .90 Do .24 .30 .08 .00 .18 Tr. .00 Do a Sept. 1-22. Monthly precipitation, in inches, at stations in British Columbia and Yukon Territory, 1901-1912. Station. Year. Jan. Feb. Mar. Apr. May. June. July. Aug. Sept. Oct. Nov. Dec. An- nual. Atlin, British Columbia . 1905 1906 1.06 .78 0.48 1.45 1.55 2.55 0.76 .88 Do 1.37 0.72 Tr. 0.25 1.74 i.62 0.71 Do 1907 .99 2.18 .55 0.09 -.34 .32 .42 1.48 .58 .82 2.34 .51 10.62 Do 1908 1.08 .60 1.76 .08 .14 .89 .21 .80 1.96 1.49 1.48 .95 11.44 Do 1909 .33 .53 2.12 .36 .49 .51 1.92 1.82 2.54 1.37 .70 .28 12.97 Do 1910 .68 .88 1.30 .88 1.06 1.28 2.11 1.03 .57 .62 .73 1.17 12.31 Do 1911 .75 1.35 1.17 .10 .16 .74 .41 1.69 1.96 .59 1.12 1.68 11.72 Do 1912 .80 .37 .08 .26 .17 .26 .50 1.77 .51 1.25 .60 1.39 7.96 Dawson, Yu- kon Terri- tory 1901 1902 .94 .86 1.32 3.32 1.64 2.38 1.17 1.17 2.25 .92 1.10 1.10 1.55 .80 Do 1.73 .20 .00 .50 .46 13.44 Do 1903 .50 1.35 .60 .60 .39 .50 1.11 1.47 2.41 1.25 .45 .65 11.28 Do 1904 .82 .32 .20 .57 .96 1.71 2.14 1.66 1.01 .36 .80 1.45 12.00 Do 1905 .23 1.30 .40 .94 .97 .25 1.93 2.51 3.52 1.84 .24 1.24 15.37 Do 1906 1.26 .51 .22 .42 2.00 .92 1.20 1.46 1.14 .47 1.55 .93 12.08 Do 1907 1.53 .34 .^8 .23 1.06 .85 1.93 1.28 2.34 .47 2.60 .62 14.13 Do 1908 .71 1.00 .71 .32 1.43 1.23 2.43 1.08 1.25 .69 1.48 1.96 14.29 Do 1909 .30 .48 1.21 .64 .81 2.66 2.10 .81 2.40 .96 .67 1.17 14.21 Do 1910 1.31 .22 .68 1.68 .19 1.44 .82 1.67 1.34 1.67 1.46 1.60 14.08 Do... 1911 1.52 .91 .77 1.30 1.68 .87 1.37 1.39 .86 1.60 1.05 1.70 15.02 Do 1912 .20 1.05 .60 .00 .38 .75 2.48 1.59 .00 .00 1.12 2.09 10.26 White horse, Yukon Ter- ritory 1904 1905 1.50 1.20 .30 .30 Do 1.72 .00 .18 .10 .15 .20 3.30 .92 2.10 1.50 11.67 Do 1906 .55 .75 .00 .23 .65 1.72 1.55 1.39 .55 .30 1.10 .20 8.99 Do 1907 .55 .52 1.45 .08 .27 3.03 5.10 1.63 .86 .26 .90 .30 14.95 Do 1908 1909 .08 .30 Do .45 .30 .40 2.55 .64 .87 1.98 2.34 .97 .60 .90 12.30 Do 1910 .18 .06 .30 .02 .03 .66 4.67 1.36 .50 .00 .10 .33 8.21 Do 1911 .20 GENERAL FEATURES. 39 Mean monthly precipitation at stations in Yukon- Tanana region and Yukon Territory. Station. Circle Eagle Fairbanks... Fort Gibbon Kechumstnk North Fork. Rampart Atlin, Brit- ish Colum- bia Dawson , Yukon Territory . Whitehorse, Yukon Territory . Length of record. Yr. m. 6 15 11 7 5 4 Jan. 18 0.90 65 .51 32 1.20 91 .79 37 .28 17 .63 18 .71 .86 .92 .61 Feb. 0.43 .38 .38 .59 .13 .26 .55 .94 .70 .33 Mar. 0.40 .51 .62 .56 .18 .18 .57 1.00 .57 .47 Apr. 0.78 .49 .18 .21 .25 .40 .28 .30 .65 .60 May. 0.39 .89 .48 .92 1.13 1.66 .61 Tune. 1.22 1.48 1.74 .84 1.91 2.33 1.21 .82 1.08 1.30 July. 1.83 2.10 1.51 2.05 2.20 2.13 1.62 1.03 2.01 3.32 Aug. 1.63 2.28 1.65 2.49 1.86 2.04 1.64 1.33 1.58 1.53 Sept. 1.97 1.31 1.42 1.17 1.03 1.53 1.13 1.25 1.55 1.00 Oct. 0.40 1.01 .78 .78 .63 .91 1.77 1.01 1.04 .53 Nov. 0.75 .52 .60 .58 .40 .42 .59 1.38 1.14 .95 Dec. 0.83 .51 .97 .59 .21 .29 .73 .95 1.31 .26 Year. 11.53 11.99 11.53 11.57 10.21 12.58 11.41 11.24 13.49 11.25 Precipitation records have not been kept long enough and are not widely enough distributed over the area to justify conclusions in regard to the laws governing the rainfall. However, they indicate certain characteristics and well-defined tendencies which will be briefly noted. The precipitation during a given period at the different stations, though frequently differing widely in total amount, exhibits to a shght degree the influence of certain general phenomena. The differences in totahty are readily explained by a consideration of the way the storms occur, a large portion of the precipitation falling in storms that are very generally distributed but that differ considerably in their intensity. In addition to the rather infrequent general rains there are frequent small showers which are very local in their nature. The monthly or annual rainfall is the summation of these irregular distributions and obviously its amount may vary widely at different stations if the period of the record is not long. The mean annual rainfall, however, as shown in the longer records, is remarkably uniform from the headwaters of the Yukon, at Atlin, British Columbia, to the mouth of the Tanana, at Fort Gibbon. Hence the physical factors producing the rainfall are probably very similar over this entire area. It seems safe to assume that the mean annual rainfall in the Yukon-Tanana region is approximately 12 inches. As might be deduced from the foregoing observations, the local variation in annual rainfaU is relatively wide. The extreme varia- tion recorded is at Rampart, where a minimum of 5.32 and a maxi- mum of 15.53 have occurred. The record at Dawson, Yukon Terri- tory, is the most uniform, but this is believed to be due simply to chance, for it is unhkely that Dawson differs physically from other stations. The data are insufficient for making a definite estimate of 40 SUEFACE WATER SUPPLY OP YUKON-TAN-AKA REGIOlSr, ALASKA. the limiting extremes of annual rainfall or for determining any rela- tion between extremely dry and wet periods. (See ^g. 2.) t> 00 04 O »-t O O O rH T-l Oi ^ 0> Oi o> <0 -C^ OO OS O <3 -O O 05 Oi CDt-OOCSOMeO'^i'5«»t~' -00 Oi O «-• d C>0<00,-IC>oOOOiOoOtHi-l ^ EAGLE FAIRBANKS RAMPART DAWSON,Y.T, Figure 2. — Eluctuation of annual rainfall at Alaska stations. Figure OCT. DEC. JAN. FEB. MAR. APR. MAY JUNE JULY AUG. SEPT. 3.— Average mean monthly precipitation at seven Weather Bm^eau stations in the Yukon- Tanana region. 145^ ^-^J) hs'^i. ^.% itex: V ^■9\ ^o ?-y.'^2>.^ o e>. b ," fcj j.'^.C't' '0.3' c- ^. j-.sj cV, g.V& .?i?3: ^^: .'-•?, 'L- 1; t'J ^;. jft^'O!^. «i>,^ tJ.t-;e3>, 145". -TANANA REGION. U.S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 342 PLATE II m 9 - p' i FtGibbon i^% MAP SHOWING DISTRIBUTION OF TIMBER IN THE YUKON TANANA REGION, ALASKA so holes MAP SHOWING DISTRIBUTION OF TIMBER IN YUKON-TANANA REGION. GENEEAL FEATURES. 41 The distribution of the rainfall throughout the year also varies con- siderably. A single amiual record may show no well-defined tendency in distribution except the greater fall in the summer months. How- ever, a very definite distribution is shown by the monthly means for a number of years, and especially by the average of these means for a number of stations. (See fig. 3.) The composite record shows that July and August have the highest precipitation and that February, March, and April have the lowest. In the four months, June, July, August, and September, about 59 per cent of the annual rainfall occurs. It is interesting to note that the rainfall in the Yukon- Tanana region, both in distribution through the year and in amount, is comparable to that of the semiarid States on the eastern slopes of the Rocky Mountains. The records are far too inadequate for deductions regarding the effect of elevation on rainfall. During the summer the higher moun- tains have often been observed to be enveloped by fog and storm clouds to a considerably greater extent than the lower country, and a higher precipitation on them seems probable. The streams head- ing in the higher mountains appear to have a slightly greater run-off than those with lower drainage basins. It therefore seems very likely that elevation increases rainfall. It is doubtful, however, whether it does so materially. VEGETATION. In the Yukon-Tanana region the climatic records show that the mean monthly temperature exceeds 50° for but three months in the year, June, July, and August, and that as a rule the temperature drops to the freezing point in each of these months. Also it has been noted that the ground remains permanently frozen over large areas and during the summers is thawed to shallow depths only. From these facts it is evident that conditions are not generally favorable for a very great plant growth during one season. The most common kind of vegetation is the thick covering of moss, which is found very extensively over all interior Alaska. Underneath this moss there is a thick turf known as tundra, which consists of a wet spongy mass of moss roots and accumulated vegetable matter. Spruce trees grow very extensively over the area and are of great economic importance both for construction purposes and for fuel. Most of the trees are rather stunted because of the frozen ground, but exceptional specimens measure as much as 3 feet in diameter at the base. Large trees are a pretty good indication that the ground is thawed, thus affording an opportunity for deep root growth. The greater part of the timber of commercial value is found below an elevation of 2,000 feet (see PI. II), although many small clumps of trees suitable for making the ordinary 12-inch sluice-box lumber are 42 SUKFACE WATER SUPPLY OP YUKON-TANANA REGION, ALASKA. found aboYe that altitude and very many more large enough for fuel grow in favored localities up to 2,500 feet. Thick stands of spruce timber 6 to 18 inches in diameter occupy a narrow belt along most of the course of the Yukon and Tanana rivers in this region. Some of the larger tributaries of these rivers also have fair growths of commercial-size spruce, which, however, has been considerably depleted on those in reach of the mining districts. Chena River has probably furnished more lumber than any of the other tributaries of the Tanana. Fairbanks received nearly its entire supply of saw logs from that source and each summer thou- sands of logs are floated down the river and through the Chena Slough to the mills to be sawed for local use. The Fairbanks district uses annually between 60,000 and 80,000 cords of wood, and the annual product of the three sawmills is probably between 6,000,000 and 8,000,000 board feet. 1 Birch trees a foot or less in diameter grow in thick clumps over many small areas and are particularly valuable for fuel. Cot- tonwood groves are frequently seen along the larger streams and adjoining slopes, and many of the trees attain diameters of 6 to 12 inches at the base. Some scattered tamaracks also grow in this area. One of the determining factors in the mining industry is the timber supply, not only for fuel but for constructing flumes, mine supports, and buildings. So far demands ha^e been fairly met by the local growth, but large inroads on this have now been made by both legitimate uses and by forest fires, and the distance timber has to be transported is gradually increasing with a corresponding increase in cost. Most of the wood sold for fuel probably brings from $10 to $15 per cord delivered at the mines, but some of it may sell as low as $6 or as high as $20 per cord, depending on distance from market, labor conditions, and kind of wood. Rough sawed lumber varies widely in value, ranging perhaps from a minimum of $40 per thou- sand feet board measure at the Fairbanks mills to as much as $200 per thousand for whipsawed lumber at the more isolated camps. Most of the higher ridges, except such as are particularly rocky and barren, bear a growth of thick, tough brush, locally known as ''buck brush." In some of the gullies and ravines cutting the moun- tain slopes and in fringes along many of the smaller streams grow almost impenetrable thickets of alders and willows. Beyond this the spruce prevails, being generally largest and best on the bottom lands adjoining the larger streams. Exceptionally, however, the best growth is near the timber line and the trees diminish in size toward the bottom lands, on which thrive the smaller species of vegetable growth. 1 Railway routes in Alaska: 62d Cong., 3d sess., H. Doc. No. 1346, p. 51, 1913. GENERAL FEATURES. 43 From early in June until the frosts occur in August grass suitable for grazing can generally be found on the southern slopes and bottom lands. On areas that have been burned over red-top grass springs up in abundance and grows waist-high in some favored localities. Many berries grow abundantly during the summer ; blueberries are found nearly everywhere; small but fine-flavored cranberries can be gathered in many places, and in some localities raspberries and currants are abundant. Experience has shown that many varieties of vegetables can be profitably grown for local use. In the vicinity of Fairbanks agri- culture is extensive, and in nearly every small town and in many outlying districts gardening has proved successful. Oat hay grows luxuriantly in the Tanana Valley and in favored localities along the Yukon, and, if cut green and properly cured, furnishes excellent forage. TRANSPORTATION. From Seattle to the Yukon-Tanana region there are three main routes of travel, all of which, compared with the means of transpor- tation in the States, are very slow and expensive, though more com- fortable than is popularly supposed. The first, commonly known as the Dawson route, comprises 1,000 miles of ocean travel from Seattle to Skagway by the 'inside passage," which is protected from the rough sea by many small islands. From Skagway to Wliite Horse, at the head of navigation on Yukon River, the trip of 110 miles is made by rail over the White Pass, thence down the Yukon by steamboat to Dawson, a distance of 460 miles. Here passengers and freight are ordinarily transferred to American boats for the remainder of the trip to Fortymile, Eagle, Circle, Rampart, Tanana, and other interior points. At Tanana, at the mouth of Tanana River, about 700 miles below Dawson, most of the freight and pas- sengers for Fairbanks, Hot Springs, and other mining centers of the Tanana VaUey are transferred to smaller boats that ply Tanana River. Fairbanks, on the Chena Slough, 275 miles above Tanana, can be reached by ri^er steamers, except at low water, when a transfer is made at the mouth of the Chena Slough, 12 miles below Fairbanks, to the Tanana VaUey Railroad. At favorable stages of water small steamers navigate as far as the mouth of Delta River, and one steamer reached the mouth of the Nabesna above the Tanana crossing. With- out delay at transfer points the trip from Seattle to Fairbanks can be made in about two weeks. A much longer time is taken in return- ing by the same route because of the slow progress going upriver against the current. This route is open for travel from the early part of June until the later part of September. The second route from Seattle is 2,700 miles by ocean boat to St. Mchael, thence by river steamers over 800 miles uj) the Yukon to 44 SURFACE WATER SUPPLY OF YUKON-TANANA REGIOI^, ALASKA. the mouth, of the Tanana, then to the several distributing points along those streams. This route is the more favorable for freight because of the somewhat cheaper rates, but it has the disadvantage of a shorter season and of taking three to four weeks for the inward trip. In going out from Fairbanks to Seattle the time required is about the same as going upriver via Dawson and Skagway. Freight rates from Seattle to Fairbanks are from $50 to $150 per ton, with an average of about $75, depending on classification. Passenger rates are about $130 first class and $100 second class. The third, or overland, route is used mainly in the winter. Ocean boats make frequent and regular trips from Seattle to Cordova or Valdez, a distance of about 1,200 miles, requiring from four to six days. From Cordova the route leads by the Copper River Railroad to Chitina (131 miles from Cordova), then 264 miles by stage to Fairbanks. From Valdez the journey of about 360 miles is made entirely by stage. For passengers and mails this route is used exten- sively during the winter months, but its cost is so great that only urgent freight can bear the expense. The Tanana Valley Railroad has 46 miles of narrow-gage track between Fairbanks, Chena, and Chatanika. Wagon roads have been built from Fairbanks to the more important producing creeks. Win- ter roads have been constructed from Fairbanks to Circle and Hot Springs, and a fairly well defined summer trail leads from Fairbanks to the Miller House in the Birch Creek district. The principal mines adjacent to Rampart and Hot Springs a reconnected with Yukon and Tanana rivers by fair wagon roads. The Birch Creek mines are reached by a wagon road from the Yukon at Circle to the Miller House, a distance of about 50 miles. Summer and winter trails leading to more isolated diggings connect with the wagon road at various points. The Fortymile and Seventymile placers are very inaccessible and can only be reached in the summer by poHng boats and pack animals. Most of the freight is transported during the winter, when the frozen swamps and rivers furnish soHd footing for horses and sleds. About 16 miles of wagon road, built from Eagle to the summit of the divide at the head of American Creek, has become nearly impassable from lack of maintenance. Even the mines most favorably connected with roads and river steamers are so handicapped by excessive operating costs that only the richer can be worked at a profit. The proper development of the low-grade placer ground in the Yukon-Tanana region must await the construction of rail and wagon roads and lower transportation charges. All the principal towns are connected by telegraph both locally and with outside points. GENEEAL FEATURES. 45 WATER-SUPPLY CONDITIONS AND THEIR ECONOMIC EFFECT. SEASONAL DISTRIBUTION. Precipitation in the form of rain or snow is the primary source of all water supply. In the Yukon-Tanana region the chief factor influ- encing the distribution of this supply is the imperviousness of the frozen ground, which prevents any considerable underground storage and makes the run-off less uniform than it is in warmer climates, where the main source of supply during low-water periods is derived from rainfall and melting snow which has seeped into the ground and has percolated to a final junction with the surface watercourses at a lower elevation. This source, however, is relatively insignificant in this latitude. The winter accumulations of snow and ice are of great value in drift mining, in which a few weeks of abundant spring flow commonly suffice to wash the gold-bearing gravels hoisted during the entire winter. In the open-cut works, however, where the progress is directly dependent on the water supply from day to day, the spring flow is of little value, for it comes at a time when the ground is ordi- narily covered with ice and snow, and work of this nature is impos- sible. Of course many of the mines lie in the lower valleys, where the ice disappears before the winter accumulations in the upper valleys and hills are exhausted, but even at these the spring floods are gen- eraUy of such short duration that they are not usually considered a very valuable asset. An additional supply of water, though one of minor importance, is that derived from the thawing of frozen ground during the summer. The summer low- water flow of the streams that rise in the higher and more rugged moimtains is kept up by the melting of large bodies of ice and snow in the sun-protected gulches and rock crevices. The rainfall, however, is not so well conserved in these streams as in more gently sloping valleys and pondage areas, where the rim-off, in per- centage of the rainfall, even though less than in higher regions, may be so distributed as to furnish the better supply. The moss that forms a heavy covering over most of the country probably regulates the distribution of the run-off during the summer as much as any factor. It is quite generally the opinion among the older residents of the country that the flow of the creeks does not hold up as weU after a rain now as when work first commenced. That probably is due in part to the fact that the moss covering on the older creeks has been largely removed by fires and other agents. Another reason may be that present-day methods of mining require more water than those practiced in years gone by, and thus the low- water conditions are now more thoroughly realized. 46 SUKFACE WATEE SUPPLY OF YUKON-TAN ANA EEGION, ALASKA. EFFECT OF TOPOGRAPHY. The topography of the Yukon-Tanana region controls to a great extent the available water supply. The upland area, constituting an old valley floor, has been dissected by numerous streams, all of which necessarily rise at about the same level because of the com- paratively uniform elevation of the original land surface. Most of the mines are situated near the heads of the small streams which do not furnish sufficient water to supply their needs. Auxihary supplies of water can be obtained only from creeks whose sources lie at about the same altitude as the stream whose supply is to be augmented. Therefore a ditch or pipe line must have its intake near the head of the creek, where the drainage basin is small and the supply uncertain. The source of a gravity supply must of course be higher than the place at which it is used; for hydraulic mLaing, where the water is used under pressure, the source should be several hundred feet above the point of utilization. The streams all have about the same grade and drop rapidly for a short distance near their heads and then take a more moderate grade through their central portions. Another serious drawback is the lack of natural storage basins above the mines that could with reasonable expense be made to conserve the excess water from rains or melting snow. As a result the water supply available for mining is the daily flow of the stream at the point of diversion. The total run-off during the mining season on many of the smaller streams (from which the supply must neces- sarily be drawn because of the altitude of the mines) would, if dis- tributed uniformly, be ample for ordinary mining. These streams, however, because of the frozen soil, steep slopes, and lack of natural storage, are very flashy. They rise rapidly after a rain but fall back to a low stage almost as quickly and then very slowly diminish until the next rain. WINTER SUPPLY. WINTER GLACIERS. In the interior of Alaska, where from about the first of November until the first of May the mean monthly temperature is below freez- ing, the stream flow must necessarily be derived from ground-water sources and must reach the surface in the form of springs. On the smaller streams and on many with catchment areas as great as 300 or 400 square miles the underground supply is insufficient to main- tain a free channel. In the autumn and early in the winter the ice gradually freezes deeper and deeper until it extends to the bed of the streams. This forces such part of the run-off as is unable to find its way through the thawed gravels beneath the channel to rise through GENERAL FEATURES. 47 the ice to the surface, where it spreads out and freezes rapidly, forming large bodies of ice locally known as winter glaciers. Some such '' glaciers" reach thicknesses of 15 to 20 feet and extend over large areas, especially in valleys where the gravels are shallow and the underground cross section of the channel is constricted by reefs of bedrock approaching the surface. RUN-OFF. On Minook, Huthnana, and Hoosier creeks an open flow is main- tained for some distance during the winter by thermal springs and similar conditions of winter flow are said to occur on other streams in this region. Such springs are probably deep-seated and are not typical of the country as a whole. In order to gather some idea of the amount of run-off from the Yukon-Tanana region during the winter several discharge measure- ments were made early in the spring. It is beheved that they were all taken before any increased flow from melting snow or ice had reached the streams. They therefore probably represent very closely the minimum surface run-off past the measuring sections for the season from the basin above the point of measurement. The results of these measurements are given in the following table: Winter discharge measurements in the Yukon-Tanana region, 1909-1911. Date. 1909. Apr. 20 May 1 1910. Apr. 6 8 17 21 191] Apr. L. 24 Stream and locality. Hutlinana Creek above Cairo Creek . Yukon River at Rampart Tanana River, 3 miles below Chena. Chatanika River below Poker Creek Salcha River at mouth Chatanika River below Faith Creek. Yukon River at Eagle , Drainage area. Sq. miles. 42.7 20G, 000 24, 000 456 2,170 132 122, 000 Dis- charge. Sec.-ft. a 0.4 10, 900 4,450 1.91 64.5 0.0 10, 100 Discharge per square mile. Scc.-fi. 0. 053 .185 .0042 .030 .0 .083 a This flow was entirely from hot springs which rise in the creek bed just above the gaging station. Above the springs the creek was frozen solid. The above table shows clearly that in the winter the surface run-off per square mile from small basins is less than from larger ones. If the measurements are accepted as typical they furthermore show that ordinarily streams draining areas less than 200 or 300 square miles would have no free surface discharge. 48 SUKFACE WATER SUPPLY OF YUKON-TAN AN A EEGION, ALASKA. SUPPLY AVAILABLE FOR MINING PURPOSES. Prior to the recent beginning of quartz mining in the Fairbanks district; drift mining was the main industry in that region from about October 1 to May 1. With the exception of two or three outfits on Fairbanks and Ester creeks, that do some sluicing during the winter, work was confined to hoisting the pay gravel to the surface, where it was accumulated in large dumps and was washed early in the summer when the water supply was increased by melting snow and ice. With the advance of quartz mining the necessity of obtaining a continuous supply of water for washing the crushed rock will confront the mill operators. The smaller streams do not maintain a definite surface-channel flow beneath the ice, and each stream presents a problem peculiar to itself. From 500 to 1,000 gallons of water are required to wash a ton of ore. The average duty of a miner's inch would be about 15 tons of ore per 24 hours, which is about the capacity of the average 5-stamp mill. Unless there is a sufficient flow in the mine that can be pumped to the mill the water in the winter must be obtained by intercepting the flow through the gravels in the stream bottoms. The existence of such flows and the best means of diverting them can be determined only by an intimate knowledge of local conditions. It will probably be found more eco- nomical to locate the mill near the water supply and transport the ore downhill than to build the mill at the mine and pump the water to any considerable elevation. On creeks where much prospecting or placer mining has been done a sufficient knowledge of the amount of underground flow in the winter should be available to determine the feasibility of using it for milling. On Ester Creek, where sluicing was continued throughout the winter of 1910, the ground was thawed, and a small flow of water was encountered in the mine. A 3-inch pump kept the mine drained, and by turning the exhaust into the sump hole warm water was fur- nished for sluicing. In order to conserve this supply and have a continuous head, the water as it drained from the tailing pile was directed into a settling reservoir, where it was warmed by the exhaust from a pump that raised it again to the sluice. Steam pipes were laid along the sluice boxes, and no serious difficulties were encoun- tered with ice even where the temperature was as low as 60° below zero. Similar methods have been employed on Fairbanks Creek. These examples serve to show what can be accomplished in main- taining a sufficient flow of water for mining from a small source under extremely low temperatures. Small miUs of 5 to 10 stamps, such as are likely to be operated in the Fairbanks district, will not require such large quantities of water as are needed for plac6rs. SURFACE WATER SUPPLY OF YUKOIiT-TANANA REGIOK, ALASKA. 49 STREAM FLOW. TERMS USED. The volume of water flowing in a stream — the ''run-off" or ''dis- charge" — is expressed in various terms, each of which has become associated with a certain class of work. These terms may be divided in two groups, (1) those which represent a rate of flow, as second- feet, gallons per minute, miner's inches, and run-off in second-feet per square mile; (2) those which represent the actual quantity of water, as run-off in depth in inches and acre-feet. They may be defined as follows : "Second-foot" is in most general use for all classes of work, and from it the quantity expressed in other terms may be obtained. It is an abbreviation of "cubic foot per second," and maybe defined as the unit for the rate of flow of water flowing in a stream 1 foot wide and 1 foot deep at the rate of 1 foot a second. To obtain the actual quantity of water it is necessary to multiply the number of second- feet by the time. "Second-feet per square mile" is the average number of cubic feet of water flowing per second from each square mile of area drained, on the assumption that the run-off is distributed uniformly as regards both time and area. "Run-off (depth in inches on drainage area) " is the depth to which the drainage area would be covered if all the water flowing from it in a given period were conserved and uniformly distributed on the surface. It is used for comparing run-off with raiafall, which is expressed in depth in inches. The "miner's inch," the unit used in connection with placer mining, also expresses a rate of flow and is applied to water flowiag through an orifice of a given size with a given head. The head of the water and the size of the orifice differ in different localities, thus making the miner's inch a most indefinite and unsatisfactory unit. Owing to the confusion arising from its use, it has been defined by law in several States. The California miner's inch is in most common use in the United States and wasVlefined by an act of March 23, 1901, as follows: "The standard miner's inch of water shall be equivalent or equal to IJ cubic feet of water per minute, measured through any aperture or orifice." This miner's inch corresponds to the so-called "6-inch pressure" and is one-fortieth of a second-foot. "Sluice head" is a term used commonly among placer miners in expressing the rate of flow through a series of sluice boxes that is necessary to separate the gold from the gravel. It is not a definite term because the rate of flow necessary varies with the size of the sluice boxes, the grade at which they are placed, and the character of the gravel. A sluice head under the varying conditions has been found to vary from 0.75 second-foot to 2.50 second-feet. 42913°— wsp 342— 15 4 50 SURFACE WATER SUPPLY OF YUKON-TAN^ANA REGION, ALASKA. CONVENIENT EQUIVALENTS. The following is a list of convenient equivalents for use in hydraulic computations : 1 second-foot equals 40 California miner's inches (law of , Mar. 23, 1901). 1 second-foot equals 38.4 Colorado miner's inches. 1 second-foot equals 40 Arizona miner's inches. 1 second-foot equals 7.48 United States gallons a second; equals 488.8 gallons a minute; equals 646,317 gallons a day. 1 second-foot for one year covers 1 square mile 1.131 feet or 13.572 inches deep. 1 second-foot for one year equals 31,536,000 cubic feet. 1 second-foot for one day equals 86,400 cubic feet. 1,000,000 United States gallons a day equals 1.55 second-feet. 1 foot equals 0.3048 meter. 1 mile equals 1.60935 kilometers. 1 mile equals 5,280 feet. 1 acre equals 43,560 square feet. 1 cubic foot of water weighs 62.5 pounds. 1 horsepower equals 550 foot-pounds a second , 1 horsepower equals 76 kilogram-meters a second. 1 horsepower equals 746 watts. 1 horsepower equals 1 second-foot falling 8.80 feet. IJ horsepower equals about 1 kilowatt. To calculate water power quickly: '- — ^-^j =net horsepower on water wheel realizing 80 per cent of theoretical power. FIELD METHODS. On account of the intense cold of the winter season in interior Alaska the stream flow during that period is very small and is con- sequently of little economic value for mining or power purposes. The data of stream flow given in this paper were collected during the summer and no attempt has been made to estimate the winter flow. Discharge measurements and gage heights are the basic data from which the daily discharge of a stream may be determined. Discharge measurements of streams in open channels may be made (1) by measurements of slope and cross section and the use of Chezy'a and Kutter's formulas, (2) by means of a weir or dani; and (3) by measurements of the velocity of the current and of the area of the cross section. The method chosen depends on the local physical conditions, the degree of accuracy desired, the funds available, and the length of time that the record is to be continued. Slope method. — The slope method involves the use of empirical formulas derived by Chezy and Kutter, which make the discharge a function of the slope, the cross section, the wetted perimeter, and a coefficient which depends for its value upon the roughness of the stream bed. It is most commonly used for measuring large streams which have a uniform slope or for estimating the flood discharge of a stream when the only data available are the cross section, the slope STEEAM FLOW. 51 as shown by marks along the bank, and a knowledge of the general conditions. It is in general only roughly approximate and is seldom used by the engineers of the United States Geological Survey. More complete information regarding the method may be obtained from textbooks on hydraulics. Weir methods. — The weir method makes the discharge dependent upon the head of water flowing over the crest of a weir, the length of crest, and certain coefficients determined by the type of the weir. Standard types of weirs for which accurate coefficients have been determined by experiment give very satisfactory records if properly maintained.^ The proper installation of weirs in the Alaskan work is usually out of the question on account of expense, the torrential character of the run-off, and the temporary nature of the stations. Velocity metJiod. — By the velocity method the two factors required to determine the discharge of a stream past a section perpendicular to the mean direction of the current are the mean velocity of flow normal to the section and the area of the cross section. Direct observations of depth and velocity are made at definite points. The distribution of these points across the section is determined by the uniformity and smoothness of flow and the depth and width of the stream. In general they should not be spaced farther apart than 5 per cent of the channel width nor more than the approximate mean depth at the time of measurement. The measuring points divide the total cross section into strips at each end of which the depth and velocity are known. The discharge through any strip is assumed to equal the product of the average of the depth at the two ends multiplied by the width of the strip multiplied by the average of the mean velocities at the two ends of the strip. The sum of the strip discharges is the total discharge of the stream. Depths for the determination of the area may be obtained by sounding with a rod or a cable. The principal methods of measuring the velocity of flow are by floats and current meter. Floats are not used by the engineers of the United States Geological Survey except under unusual conditions, but as float measurements can readily be made by the prospector the method is described below. The floats in common use are the surface, subsurface, and tube or rod floats. A corked bottle with a flag in the top and weighted at the bottom makes one of the most satisfactory surface floats, as it is affected but Httle by wind. In flood measurements good results can be obtained by observing the velocity of floating cakes of ice or debris. In all surface-float measurements the observed velocity must be 1 The determination of discharge over the different types of weirs and dams is treated fully in '"'Weir experiments, coefficients, and formulas" (U. S. Geol. Survey Water-Supply Paper 200), and in text- books on hydraulics. 52 SUKFACE WATER SUPPLY OF YUKON-TAN ANA REGION, ALASKA. multiplied by 0.85 to 0.95 to reduce it to the mean velocity. The subsurface and tube or rod floats are intended to give directly the mean velocity in the vertical. Tubes give excellent results when the channel conditions are good, as in canals. If it is desired to estimate roughly the discharge of a small creek or canal, a portion of the channel is selected which is straight and of nearly uniform cross section and through which the water flows smoothly. The length of this stretch, or ''run," should be 50 to 200 feet, but in many places it is necessarily less than this because of conditions in the channel. Floats of any simple type may be used. A number of determinations of their time of passage over the ''run" are made and the average time in seconds for one passage is com- puted. The length of the "run" divided by this time and multiphed by 0.85 will give the approximate mean velocity in feet per second through the section. The average depth multiplied by the width of the stream gives the area of its cross section in square feet; this multiphed by the mean velocity will give the approximate discharge in second-feet. . If a more reliable estimate is desired, the location of the floats in the section may be determined, the depth of the stream at these points may be ascertained by sounding or from a developed cross section, and the discharges of the elementary sections may be com- puted, as already described. In a large stream the coefficient for reducing surface velocity to mean velocity may be determined by taking occasional vertical velocity curves across the section with a current meter. If sufficient care is taken and conditions are good, a float measurement may possess a high degree of accuracy. The Price current meter is used by the United States Geological Survey almost to the exclusion of meters of other types to determine the velocity of flow of water in open channels. The smaU Price acoustic and electric meters were the types used in the work in the Yukon-Tanana region. (See PI. Ill, A.) The meter consists of six cups attached to a vertical shaft which revolves on a conical hardened- steel point when immersed in moving water. The number of revolu- tions is indicated acoustically or electrically. The relation between the velocity of the moving water and the revolutions of the wheel is determined for each meter by drawing it through still water for a given distance at different speeds and noting the number of revolu- tions for each run. These data form the basis of a meter rating table which gives the velocity of moving water in feet per second for any number of revolutions in a given period. Meter measurements of the flow of a stream may be made from a bridge, from a cable and car instaUed especially for the purpose, from boats, or by wading. The majority of the measurements published in this report were made by wading with the acoustic meter attached to a rod. (See PI. Ill, B.) U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 342 PLATE III ' :.y mi^maairim'miimMm Wi ^^^^ wmscm:!^M. wiam» A. SMALL PRICE CURRENT METERS. B. WADING MEASUREMENT. Stream flow. 53 Three methods of measuring the velocity were used. In the first the meter is held at the depth of the thread of mean velocity, which has been found by repeated experiments to be located at about 0.6 of the total depth. In the second method the mean of the velocities obtained at 0.2 and 0.8 depth is taken as the mean. This method has been shown to give the mean velocity very accurately, and it is now used very extensively by the United States Geological Survey. In the third method the meter is held near the surface, usually 1 foot below, or low enough to be protected from the wind or other dis- turbing influence. The coefficient for reducing this velocity to the mean has been found to be from about 0.85 to 0.95, depending on the stage, the velocity, and the conditions of the channel. This method was used principally for boat measurements on large streams or on streams at flood stages. The determination of the flow of an ice-covered stream is difficult, owing to diversity and instability of conditions during the winter and also to lack of definite information in regard to the laws of flow of water under ice. Very few discharge measurements were made of streams under ice conditions in the Yukon-Tanana region. In these an electric meter suspended by a cable was used, observations of velocity being made at sufficiently short intervals in the vertical to determine the mean. A prime essential for obtaining accurate stream-flow records is a good gaging station. To make the record, when obtained, most val- uable, it should be made at the point on a stream where the record of flow is most likely to be needed either in the present or the future. Other requisites for good stations are (1) a permanent stream bed, (2) freedom from backwater, (3) good measuring conditions, and (4) one channel at all stages. Since gage heights are recorded for the purpose of showing the fluctuations of the stream, they should be observed at frequent intervals, and consequently the station should be located near an available observer. The sparse settlement of the Alaskan placer regions and the transient character of the inhabitants have made proximity of the observer the ruHng consideration in the estabhshment of most stations, in many places to a partial exclusion of the desirable requisites mentioned above. Where practicable, the gage heights were obtained twice a day, but in many places they could be read but once a day, and in some places only once in several days. OFFICE METHODS. At the end of each season the field or base data, consisting of gage- height records, discharge measurements, and full notes are assem- bled. The discharge measurements are plotted on cross-section paper and rating curves are drawn. The rating tables prepared 54 SURFACE WATER SUPPLY OF YUKON-TANAl^A REGHOlsr, ALASKA. from these curves are then applied to the tables of daily gage heights, and from these the monthly discharge and run-off are computed. The discharge measurements at a gaging station when plotted with the discharges in second-feet as abscissas and the corresponding gage heights in feet as ordinates, define curves which are generally more or less parabolic in form. Where measurements may be made repeatedly at the same section, curves of area in square feet and of mean velocity in feet per second may also be constructed to the same scale of ordinates as the discharge curve. These curves aid in extending the discharge curve beyond the limits of the plotted dis- charge measurements, in avoiding errors in the form of the discharge curve, and in determining erroneous measurements. Discharge, area, and mean velocity curves of Fortymile River at Steel Creek are shown in figure 4. A gaging station on an ordinary open channel without backwater will have one rating curve so long as the relation between gage heights and discharge is not altered. The rating curves are, there- fore, directly dependent on the permanency of the channel. Streams in general present throughout their courses to a greater or less degree all conditions of permanent, semipermanent, and shifting channels. These conditions are evident in the plotting of discharge measure- ments and in the construction of rating curves. Corresponding to the character of the channel a station may have (1) a permanent rat- ing, (2) a rating which is changed only at extreme high water, (3) a rating which is frequently changing and which requires discharge measurements and changes in rating at intervals dependent on the frequency or rate of the change. Although each class of rating is represented in the Yukon-Tanana region, the majority belong to the second class. Most of the smaller streams of interior Alaska have comparatively steep grades and wide fluctuations in stage. At low stages they usually meander through a wide gravel flood plain or through channels cut in the muck. Such channels can not well resist the erosive action of a good-sized freshet and during such may undergo radical changes. In a season with frequent freshets condi- tions approach those described in the third class. Discharge meas- urements should then be made frequently, and even with this pre- caution the daily estimates may be largely approximate. EXPLANATION OF TABLES AND USE OF DATA. For each gaging station there is given a table of discharge measure- ments and a table showing the gage height, the daily discharge, the mean monthly discharge, the mean monthly discharge in second-feet per square mile, the run-off in depth in inches from the drainage area, and the accuracy. STREAM FLOW. 55 GAGE HEIGHT IN FEET rv) CO g tn a o s > < O £- n o (J) m O o 20 r-1 m n H "^ N°o '0 ^ \ N^ \ cccDtD rn m m > c QUI— 2 m 1 1 1 ro z =\ \ \ \ ^ \ 0. \ \ — \ V \ 14. \ "b + cS. 0) .X \ ^ > n =+\ \ z \ \ \ "•\ \ n \ ^ \ -■I m m ^ \ \ n > \ Z - + \ \ < n ^ \ '^ H X >)^'- \ \ Z __4i '^ \ (n iA m m H <^ y- n ^0^ \ N? m .i^ \ z a — 00 J 56 SUEFACE WATER SUPPLY OF YUKON-TANANA EEGIOInT, ALASKA. The discharge-measurement table gives the results of all discharge mieasurements miade at the station. The gage heights give th^ daily fluctuations of the stream. They represent the elevation of the sur- face of the water above the arbitrary datum of the gage and not above the bed of the stream. The daily discharges are determined by application of a rating table to the gage heights. At many stations it was impracticable to obtain an unbroken gage-height record. At some stations readings could be obtained only occasionally, and at others longer or shorter breaks in the record necessarily occurred. Whenever it was considered feasible the daily discharge for these periods has been estimated. These estimates have been based on the records obtained at the station itself, on the records of neighboring stations where conditions were comparable, and on a general knowledge of conditions. For each drainage basin there are given all miscellaneous discharge measurements made in the basin at points other than the regular stations. The wide fluctuation of the streams render these miscel- laneous data of rather uncertain value. With a few exceptions they represent the flow of the various streams at medium or low stages. Records at regular stations on neighboring streams should be studied and extreme precautions should be taken before basing any impor- tant work on these measurements. ACCURACY OF DATA. The accuracy of stream-flow data depends primarily on the natural conditions at the gaging stations and on the methods and care with which the data are collected. The effect of poor channel conditions on the rating has been discussed. In a normal season errors from this cause should not be great at a station which is carefully established and rated. Practically all current-meter measurements made under fair conditions are well within 5 per cent of the true discharge at the time of the observation. As the errors of meter measurements are largely compensating, the mean rating curve, when well defined, is much more accurate than the individual measurements. Numerous tests of the accuracy of current-meter work show that where condi- tions are good it compares very favorably with results from standard weirs. The accuracy of the gage heights depends on the rehabihty of the observers, and this, with very few exceptions, is believed to be good. It is obvious that when a stream is frequently changing in stage, one reading or two readings per day may not give the mean height for the day. It seems probable, however, that errors from this soiKce are compensating if the stage does not have a diurnal cycle and are greatly decreased in the monthly mean, although the reading for a U. S. GEOLOGICAL SURVEY GEORGE OTIS SMITH, DIRECTOR WATER-SUPPLY PAPER 342 PLATE IV °??if \ ,(Z>H A N '0 '«-' ^O^UK/u K p ^^\^ % <"U^ '/I' / WfcCormi_oKs|^ "?^* ' N C T ' U % - I .11 ^ -^I::;i_j£_ J \ y^^] R A'\IV1 PAR T -- — - ^\S"'' ( ftaafri*^ -■■, .i t& ^ V^ W 'I/O k5fc-_ >C -<^ ..'^;^"~^"" C I N n^ \ LrO^^ y-s^v 1— Irp^-^ ^-^n-u^^s:^ ; . n^fr °^ ej /^(>G Li E '7^ '-■'■—-__ "^^ 93-IOO-lc ^ ° T t s ^ R , ^ C 3 ^,.- P R E,_-^ ,' 93-100-10/ \ OlneSft^p^ ^J^^y^"^!^' <^ / N c aP^^, Ctefir Creek Buttsi;;4, \hj gS^^^W' /? fWobd River Bute \^ f ;>k EC 1 N d Ti frtg ■ ^.'V, MAP or YUKON-TANANA REGION ALASKA SHOWIN& DISTRIBUTION OF MINERAL DEPOSITS AND LOCATION OF RAINI^ALL AND GAGING STATIONS Scale 1,000,000 "^^» ^ "^ % .^^§kmi:\ Compiled from maps by United States Geological Soirv^ ALfredH.Brooks,Geolog'istinchai-ge of division 1914 LEGEND ir.S.telegraphline — ^^ Pl-ol3al)le drzdna^e - — -; ■Wag'on road =;r^ Radlroad -^- — — • Trail - Gold placer x Gold lode • Tin lagmtic coal ^ Rainfall statiofn; letter refers to list in text x A Gaging station; xianiber refers to Ustia text o^S Mining precinct boundaries — — ^fining precinct bound ai'ies indefinite r^-^ ^l)L^ \a^ :^U .cr i". ' iO^ Unsuzi Mtn /^ I Lake \ % ^ 1 (RexDbin a C liN C T ,S; ij KantishnaTL PR, ^{ v. Mtr A N^A ,*I McKI NLEV-^-^- / ._>^. --o d^d 'R ; jMt McXinley .c?^ <^\ PRE / M y y )^fei7: .&*> JVadSSOsoW -\> -*^ lY/ ^Tf ■\ ^ STREAM FLOW. 5Y single day may be considerably in error if taken by itself. This is especially likely to be true in the values of the maximum and miai- mum. The maximum should be increased considerably for many stations, and the minimum value should be taken as a mean of seven days or more rather than for one day. The records of mean monthly discharge per square mile in second- feet and the run-off in depth in inches may be subject to errors resulting from a drainage area which is not well defined by available maps and to the wide variation in contribution to run-off over the drahiage area. In the table the line designated ''Accuracy" shows the degree of rehabihty which it is beheved the record possesses. It does not apply to the maximum or minimum, nor to any individual day, but to the monthly mean. It is based on the accuracy of the rating, the probable rehabihty of the observer, and knowledge of local conditions. A indicates that the mean monthly flow is probably accurate withui 5 per cent; B, within 10 per cent; C, within 15 per cent; D, within 25 per cent. Special conditions are covered by footnotes. REGULAR GAGING STATIONS. In the following Hsts are given the names of gaguig stations main- tained in the Yukon-Tanana region by the United States Geological Survey and cooperative parties and the duration of the records at each station. Numbers are assigned the stations to aid in identi- fying their location on Plates X to XIII (in pocket). The stations are grouped under river basins in downstream order, tributaries of main streams being indicated by indention. The main stem of any stream is determined by the drainage area; that is, the headwater stream having the largest drainage is considered the continuation of- the main stream and local changes in name are disregarded. (See PL IV.) Yukon River basin : No. on plate. Yukon River at Eagle, 1911-12 1 Fortymile River basin : Main stem of Fortymile River : Dennison Fork at mouth, 1912 2 South Fork of Fortymile River at Franklin, 1910-1912 3 Fortymile River at Steele Creek, 1910-1912 4 South Fork of Fortymile River basin: Mosquito Fork at Kechumstuk, 1910-1912 5 Kechumstuk Creek at mouth, 1910-1912 6 Gold Creek at mouth, 1911 7 Walkers Fork above Poker Creek, 1912 8 Walkers Fork above Cherry Creek, 1911 9 Walkers Fork above Tv/elvemile Creek, 1910 10 Wade Creek at claim "No. 10 above," 1910-1912 11 Buckskin Creek above Fortyfive Pup, 1910-1912 12 Fortyfive Pup at claim No. 13, 1910-1912 13 58 SURFACE WATER SUPPLY OF YUKON-TAITANA REGION, ALASKA. Fortymile River basin — Continued. South Fork of Fortymile River basin — Continued. No. on plate. North Fork of Fortymile River at the ' ' kink, ' ' 1910-1912 14 North Fork of Fortymile River above Middle Fork, 1910 15 Confederate Creek at mouth, 1912 16 Hutchinson Creek below Confederate Creek, 1911-12 17 Hutchinson Creek below Montana Creek, 1910-1912 18 Montana Creek at claim "No. 7 above," 1910-1912 19 King Solomon Creek at Liberty Cabin, 1911-12 20 Liberty Fork at mouth, 1911-12 21 Dome Creek at Auburn Mining Co. camp, 1912 22 Steele Creek at mouth, 1910-1912 23 Canyon Creek below Squaw Gulch, 1912 24 Canyon Creek, 1 mile below Squaw Gulch, 1910 25 Canyon Creek, 2 miles below Squaw Gulch, 1911 26 Squaw Gulch at claim "No. 1 above," 1910-1912 „ 27 Mission Creek basin : Mission Creek above Oregon Creek, 1911. 28 Mission Creek above Colorado Creek, 1910 29 Wolf Creek above Swanson's dam, 1911 30 American Creek at claim " No . 8 above, ' ' 1910-1912 31 American Creek at United States pumping plant, 1910-11 32 Discovery Fork below Star Gulch, 1910-1912 33 Seven tymile River basin : Seven tymile River above Flume Creek, 1910, 1912 34 Seventymile River at the falls, 1910-1912 35 Flume Creek one-fourth mile above mouth, 1910-1912 36 Alder Creek at claim "No. 7 above," 1910-1912 37 Barney Creek above ditch intake, 1910 38 Barney Creek ditch below forks, 1912 39 Sonickson Creek above ditch intake, 1910-1912 40 Washington Creek above dam, 1912 41 Crooked Creek below Eldorado Creek, 1910-1912 42 Fox Creek at Rolfs claim, 1911-12 43 Birch Creek basin : Birch Creek above Twelvemile Creek, 1911 44 Birch Creek below Twelvemile Creek, 1911-12 45 Birch Cr-^ek below Great Unknown Creek, 1912 46 Bii-ch Creek below Clums Fork, 1910-11 47 Birch Creek above Sheep Creek, 1911-12 48 Birch Creek at Fourteenmile House, 1908-1912. 49 Mastodon Fork of Eagle Creek above ditch intake, 1909 50 Fryingpan Creek below forks, 1910 51 Great Unknown Creek at mouth, 1912 52 Clums Fork below Munson Creek, 1912 53 Lawson Creek at mouth, 1912 54 Buckley Bar Creek at mouth, 1911-12 55 Sheep Creek at mouth, 1911-12 56 Bachelor Creek below Costa Fork, 1909-10 57 Porcupine Creek above ditch intake, 1910 58 Porcupine Creek below ditch intake, 1912 59 Porcupine Creek below Bonanza Creek, 1908-1912 60 STREAM FLOW. 59 Birch Creek basin — Continued. Birch Creek at Fourteenmile House, 1908-1912 — Continued. No. on plate. Crooked Creek at Central House, 1909-1912 61 Bonanza Creek above ditch intake, 1908-1910 62 Bonanza Creek below ditch intake, 1911-12 63 Independence Creek at claim ''No. 9 above," 1911 64 Mammoth Creek at Miller House, 1908-1910 65 Miller Creek at mouth, 1911-12 QQ Dead wood Creek above Switch Creek, 1909-1912 67 Portage Creek, 4 miles above Medicine Lake, 1912. 68 Porcupine ditch at intake, 1912 69 Bonanza ditch at intake, 1910-1912 70 Bonanza ditch below junction with Porcupine branch, 1912 71 Bonanza ditch at outlet, 1911-12 72 Mammoth Creek diversion ditch, 1910 73 Beaver Creek basin : Nome Creek, 4 miles above Moose Creek, 1912. 74 Nome Creek above Ophir Creek, 1911-12 75 Hess Creek basin : Troublesome Creek below Quail Creek, 1908-1910 76 Quail Creek at claim "No. 7 above," 1909 77 Quail Creek at claim "No. 9 below," 1909-10 78 Minook Creek basin : Minook Creek above Little Minook Creek, 1908-9 79 Hoosier Creek at claim "No. 11 above," 1908-9 80 Little Minook Creek at claim "No. 9 above," 1908-9 81 Hunter Creek at claim "No. 17 above," 1908 82 Streams tributary to Tanana River (miscellaneous basins) : Banner Creek at mouth, 1909-10 83 Salcha River near mouth, 1909-10 84 Junction Creek above Moose Lake outlet, 1909-10, 1912 85 Chena River basin : Chena River above Shamrock Creek, 1912 86 Chena River above Little Chena River, 1910-1912 87 North Fork of Chena River above Monument Creek, 1912 88 North Fork of Chena River below Monument Creek, 1912 89 Monument Creek at Chena Hot Springs, 1912 u 90 Little Chena River above Sorrels Creek, 1907-8, 1910 91 Little Chena River below Fish Creek, 1908, 1910 92 Sorrels Creek above Elliot Creek, 1907-8, 1910 93 Elliot Creek at mouth, 1907-8, 1910 94 Fish Creek below Solo Creek, 1910-1912 95 Fish Creek above Fairbanks Creek, 1907-8 96 Fish Creek at mouth, 1908, 1910 97 Miller Creek at mouth, 1908, 1910 98 Tolovana River basin : Washington Creek above Aggie Creek, 1908 99 Washington Creek below Aggie Creek, 1908 100 Aggie Creek at mouth, 1908 101 McManus Creek at mouth, 1907, 1910-1912 102 Chatanika River below Faith Creek, 1907-8, 1910-1912 103 60 SURFACE Water sxjpply op yukok-Tanana region, Alaska. Tolovana River basin — Continued. No. on plate. Chatanika River below Poker Creek, 1907-1912 104 Chatanika ditch near outlet, 1910 105 Faith Creek at mouth, 1907, 1911-12.... . ................... .... 108 Smith Creek above Pool Creek, 1911 107 Pool Creek at mouth, 1911 108 Charity Creek above Homestake Creek, 1910, 1912 103 Homestake Creek at mouth, 1910, 1912 .110 Kokomo Creek above Alder Creek, 1907 Ill Goldstream Creek at claim "No. 6 below," 1907 112 Baker Creek basin: Baker Creek at road crossing, 1908 113 New York Creek at Thanksgiving ditch intake, 1908-9 114 California Creek at Thanksgiving ditch intake, 1908-9 115 Thanksgiving ditch near outlet, 1908-9. 116 California branch of Thanksgiving ditch near outlet, 1908 117 Pioneer Creek above What Cheer Bar ditch intake, 1908-9 118 What Cheer Bar ditch at intake, 1909 119 Hutlinana Creek above Cairo Creek, 1908-9 120 Hutlinana Creek below Cairo Creek, 1908 121 Patterson Creek basin: Sullivan Creek above Tofty ditch intake, 1908-9 122 YUKON RIVER DRAINAGE BASIN. DESCRIPTION. The Yukon Eiver basin comprises the greater portion of the vast area lying between the Pacific Mountain system on the south and the Rocky Mountain system on the north. Over half of it lies in Canada, its tributaries rising far to the southeast in the rugged mountains of northeastern British Columbia and the Yukon Territory. The stream meanders northwesterly across the international boundary as far as the Arctic Circle, near which it gradually turns southwest and flows to Bering Sea. Heading in an area some portions of which are little more than a score of miles from the coast, it carries its drainage over 2,000 miles before finally discharging it into the sea. The fol- lowing table, showing the approximate lengths and drainage areas of some of the principal rivers of North America, shows the Yukon to rank fifth in size of drainage area. Length and drainage area of the principal rivers of North America. Rivers. Mississippi, with Missouri Mackenzie St. Lawrence Winnipeg and Nelson Yukon, with Lewes and Teslin Colorado and Green Columbia Ohio and Allegheny Approxi- mate length. Miles. 6,000 2,900 2,600 3,800 2,300 2,000 1,200 1,000 Approxi- mate area of drainage basin. Sq. miles. 1,244,000 677,000 565,000 486,000 330,000 300,000 259,000 210,000 YUKON EIVER DRAINAGE BASIN. 61 The main Yukon is formed by the junction of the Pelly and Lewes, about 1,500 miles above the mouth. The chief tributaries below this junction in dowTistream order are the White, Stewart, Porcupine, Chandalar, Tanana, and Koyukuk. The drainage areas of the Yukon at various points along its course are shown in the following table: Drainage areas of Yukon River at different points along its course. Above — YUKON TERRITORY. White Horse . Dawson Eagle Fort Yukon. Rampart — Mouth Distance from mouth.o Miles. 2,050 1,534 1,432 1,157 914 Drainage area. Sq. miles. 7,630 115, 000 122, 000 177,000 206,000 330, 000 a Distances as determined by Northern Navigation Co. Above Eagle the Yukon is in most places confined to one channel and is characterized by a swift current and occasional rapids. A general view of the Yukon Valley near Eagle is shown in Plate V, A. Below Eagle, in the vicinity of Fort Yukon, the river enters what is known as the Yukon Flats. For about 200 miles it flows rather slug- gishly through a wide valley in many channels and sloughs which frequently shift, causing much difficulty in navigation. The topog- raphy of the valley then changes again, and to the mouth of the Tanana the river flows for over 100 miles through a stretch which has been called the Lower Ramparts because of the rampart-like walls which bound it. In its remaining 800 miles the Yukon meanders through a valley never less than 2 miles wide in many channels and is marked by numerous islands and sand bars. A more complete description of the Yukon basin is given by Brooks.^ A station was maintained on Yukon River at Eagle during 1911 and 1912 and daily gage-height records were obtained for the greater part of the open season. Previous to this very few data on the flow of the Yukon had been collected. Approximate measurements made by Dawson ^ at the confluence of Pelly and Lewes rivers gave a dis- charge of 66,955 second-feet late in the summer when the river was at about mean stage. Ogilvie,^ who made more careful measurements of the Yukon at the international boundary, gives considerable information as to the 1 Brooks, A. H., The geography and geology of Alaska: U. S. Geol. Survey Prof. Paper 45, p. 64, 1906. 2Dawson,G.M., Yukon district and British Columbia: Geol. and Nat. Hist. Survey Canada Ann.Rept., vol.3,pt. l,p. 183,1889. 3 Ogilvie, William, The Klondike Official Guide, Buffalo, p. 56, 1898. 62 SURFACE WATER STJPPLl OF YUKON-TAN AN" A REGION, ALASKA. discharge. In December, 1895, the discharge was estimated at about 96,000 second-feet, the mean summer flow at about 135,000 second-feet, and the flood flow at 180,000 to 225,000 second-feet. Kesults at Eagle, about 12 miles below, show that Ogilvie's estimate of a mean summer discharge of 135,000 is approximately correct, but that his estimates for winter flow and flood flow are too small. On September 8, 1899, when the Yukon was at a low summer stage, a discharge measurement made 73 miles above the mouth by the Coast and Geodetic Survey gave 436,000 second-feet. Miscellaneous measurements were made of the Fifty mile River at Whitehorse, Yukon Territory, in 1908 and of the Yukon at Rampart in the spring of 1909. (See pp. 66-67.) Water^surface May 22, 191 1, at time of highest discharge measurement Water surface September I4j9l2,at time of lowest open-channel discharge measurement Pa Approximate ^,,^^^f^^^^^^^^^^////////^^^^^^ April 24, I9ll,attime of measurement through ice 200 400 600 800 1000 1200 1400 1600 DISTANCE IN FEET FROM INITIAL POINT Figure 5. — Cross section of Yukon River at measuring section at Eagle. YUKON RIVER AT EAGLE. ^ In May, 1911, a gage was estabhshed on Yukon River at Eagle, and gage readings were made from May 9 to September 30, 1911, and from May 20 to October 21, 1912. The gage consisted of a white strip about 3 feet wide painted on the rock face of a high bluff just below the town of Eagle (see PI. V, A), and graduated in black paint at intervals of a quarter of a foot, the even feet being marked by numbers sufficiently large to enable the gage to be read from Eagle, about half a mile distant, by telescope. The observer read the gage to one-eighth of a foot. Discharge measurements were made about 2 miles above Eagle by floats on a straight stretch of channel about 1,000 feet long whose cross section was beheved to be practically uniform. The river at this point is about 1,600 feet wide. About midlength of the proposed run for the float the cross section was determined by cutting holes through the ice at intervals of 50 feet and making soundings at each hole. The exposed section was determined by levels and, together with the section obtained by soundings, was referred to a permanent bench mark. (See fig. 5.) The bench mark is a notch cut in the 1 For a fuller description of this station and its record of discharge for 1913, see Porter, E. A., and Davenport, R. W., The discharge of Yukon River at Eagle, Alaska: U. S. Geol. Survey Water-Supply Paper 345-F, 1914. U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 342 PLATE V A. YUKON RIVER AT EAGLE. B. FORTYMILE RIVER BELOW STEEL CREEK. U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 342 PLATE VI A. TYPICAL TOPOGRAPHY, MASTODON CREEK. B. HYDRAULICKING ON EAGLE CREEK. YUKON EIVER DEAINAGE BASIN. 63 base of a willow at the top of the left bank 300 feet below the upper range line. The transit point at the upper end of the range Une is marked by a witness stake and a pile of stones. Seven feet back from the transit point a 2-inch birch is blazed and marked by three notches. Two prominent poplars about 6 inches in diameter stand about 50 feet back of the point and a little downstream. On April 24, 1911, the vertical velocity of the stream at the ice holes was determined by a Price current meter, and the discharge was computed as 10,100 second-feet. This is considered to be near the minimum discharge at Eagle for 1911 and it probably represents very closely the minimum from year to year. During May, 1911, seven discharge measurements were made by means of ice floats. In 1912 three measurements were made, two by driftwood floats and one by bottle floats. The iastruments used for these measurements were a transit and stop watch. The passage of ice cakes were timed over a run of 500 feet and their location was determiaed by a transit on the upstream range line. Two men decided upon a cake as it crossed the upper range, and while one man followed it with the transit telescope the other went down to the lower range and when the float crossed signaled the transit man and noted the time. For the bottle floats ordiaary beer bottles, weighted with sand and marked with flags stuck in the necks, were used. White flags were found to be the most easily visible. The floats were dropped from a rowboat at intervals of about 75 feet across the stream above the upper range line. Observations were also made to determine the coefiicient required to reduce surface velocity to mean velocity. A rowboat with a sack of rocks as an anchor was employed. The very swift current of the Yukon, with depths of 20 to 30 feet, made the task diffl- cult. It was found necessary to use 200 pounds of rocks to furnish sufficient anchorage. When observations at a point were completed the rope was cut, the boat pulled to the shore as quickly as possible, and then hauled back upstream far enough for another trial. The results of these observations indicated a coefficient of 0.92, somewhat higher than is found in most streams. This coefficient was used for the reduction of all discharge measurements. AU "the measurements plot within 3 per cent of the mean rating curve, except that of May 19, 1911, which plots 14 per cent greater, probably because of certain abnormal conditions of ice flow at the time of the measurement. Besides the records of daily discharge for the period 'of gage-height records, there is given a table showing the mean monthly discharge, run-off ia second-feet per square mile, and run-off in inches on the drainage area throughout 1911 and 1912. The portions of the years for which daily records were unavailable are based on the personal 64 SURFACE WATER SUPPLY OF YUKON-TANANA REGION, ALASKA. knowledge of conditions of winter flow and on miscellaneous measure- ments made through the ice. The error involved by such an estimate can not be great in its effect upon the total, for 77 per cent of the run-off for 1911 occurred in the 145 days of the gage-height record and 75 per cent of that in 1912 occurred in 155 days. The maximum discharge for 24 hours as given by the record was 254,000 second-feet on May 22, 1911. The discharge has undoubtedly been considerably greater than this. The ordinary winter minimum has been estimated as about 10,000 second-feet, but this is probably rather excessive for the extreme minimum. The mean daily discharge for 1911 and 1912 is computed to be 88,300 second-feet. The mean annual run-off in depth in inches in 1911 and 1912, dis- tributed evenly over the drainage area of 122,000 square miles above Eagle, is 8.18 inches. The rainfall from November 1, 1910, to October 30, 1912, is believed to have been close to normal. It seems reason- able to assume from the available precipitation records (p. 23) that the normal rainfall in this area is approximately 12 inches. If these assumptions are correct, the run-off from this area exceeds 60 per cent of the precipitation. ComparisoD of this result with various basins in the United States throws doubt on the accuracy of so high a percentage of run-off. As has already been shown, the drainage area of the Yukon presents decidedly different conditions from those in most river basins of the United States. The extensive areas of frozen ground are an obstacle to percolation, for when the upper layer of thawed earth is saturated the rainfall can only seek its way to the nearest watercourse, and it therefore escapes with a minimum of the losses which are promoted by perco- lation. The climate and topography are unfavorable for great losses by evaporation, and losses due to vegetation are small because the summer is too short and cool for luxuriant plant growth. It seems safe to state that the run-off per square mile from the drainage area of the Yukon above Eagle exceeds that of half the area of the United States. Discharge measurements of Yukon River at Eagle, Alaska, 1911-12. Date. Gage height. Dis- charge. Date. Gage height. Dis- charge. Apr. 24.. 1911. Feet. Sec.-ft. a 10, 100 b 125,200 b 125,200 b 121,400 5 215,600 6 234,700 5 237,700 1911— Continued. May 22 Feet. 11.90 3.45 9.65 -2.00 Sec.-ft. b 253,300 May 9.. 10.. 2.90 3.10 2.40 7.50 10.10 11.25 1912. May 21 16 c 126,800 19 July 29 c 222,900 20 Sept. 14 d 68,200 21 a Measiirement with current meter under ice. b Measurement with ice floats. c Measurement with floating driftwood. d Bottle floats l^sed .for determining velocities. YUKON EIVER DRAINAGE BASIN. 65 Monthly discharge of Yukon River at Eagle, Alaska, 1911 and 1912. Month. Discharge in second-feet. Mean. 1911 1912 Per square mUe. 1911 1912 Run-off (depth in inches). 1911 1912 January February. . March April May June July August September. October November. December.. 21,000 15,000 11,000 12,000 156,000 184, 000 178,000 139,000 106,000 60,000 37,000 28,000 21,000 15, 000 11,000 12,000 125,000 160,000 147,000 127,000 73, 600 51,000 37,000 28, 000 172 123 090 098 28 51 46 14 869 492 303 230 0.172 .123 .090 .098 1.02 1.32 1.20 1.04 .603 .418 .303 .230 0.20 .13 .10 .11 1.48 1.68 1.68 1.31 .97 .57 .34 .27 0.20 .13 .10 .11 1.18 1.47 1.38 1.20 .67 .48 .34 .27 The year 8.84 7.35 Daily gage height, in feet, and discharge, in second-feet, of Yukon River at Eagle, Alaska, for 1911-12. [Drainage area, 122,000 square miles. Observers: Jay Mattison, 1911; W. p. Thrall, 1912. 1 May. June. July. August. September. October. Day. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. 1911. 1 8.9 8.0 7.5 6.9 6.4 6.5 6.4 6.0 6.9 6.8 6.6 6.5 6.2 7.0 6.4 6.2 6.5 7,0 8.0 8.2 8.4 8.5 8.1 7.8 7.4 6.5 7.0 7.8 8.0 8.0 210,000 196,000 188,000 180,000 172,000 174,000 172,000 166,000 180,000 178,000 175,000 174,000 169,000 181, 000 172,000 169,000 174,000 181,000 196,000 199,000 202,000 204,000 198,000 193,000 187,000 174,000 181,000 193,000 196,000 196,000 7.9 7.8 7.1 7.0 6.9 6.8 7.0 7.1 7.2 7.4 8.6 8.2 7.4 7.0 6.0 6.2 7.8 9.0 8.0 7.2 6.6 6.0 5.9 5.9 5.5 6.0 5.6 5.5 5.5 5.4 5.8 194,000 193,000 182,000 181,000 180, 000 178,000 181,000 182,000 184,000 187,000 205,000 199,000 187,000 181,000 166,000 169,000 193,000 211,000 196,000 184,000 175,000 166,000 165, 000 165, 000 160,000 166,000 161,000 160,000 160,000 158,000 164, 000 4.9 4.8 4.5 4.8 5.0 5.5 5.5 5.0 4.9 4.4 4.2 4.0 4.1 4.1 4.0 3.9 3.9 4.2 4.8 4.6 4.5 4.2 4.0 3.9 3.5 3.0 2.5 2.2 2.0 1.9 1.5 151,000 150,000 146,000 150, 000 125,000 160,000 160,000 152,000 151,000 144,000 141,000 138,000 140,000 140,000 138,000 137,000 137, 000 141,000 150,000 147,000 146,000 141,000 138,000 137,000 132,000 125,000 118,000 115,000 112,000 111,000 108, 000 1.5 2.0 4.5 4.0 3.8 3.2 3.0 2.5 2.1 1.9 1.5 1.5 2.0 1.9 1.6 1.4 ""'o.'i "'-6.' 5 108,000 112,000 146, 000 138,000 136,000 128,000 125, 000 118,000 114,000 111,000 108,000 108,000 112,000 111,000 109,000 106,000 105,000 103,000 102,000 100,000 98,000 96,000 94,000 92,000 90,600 88,000 84,000 82,000 80,000 78,000 2 .. . 3 . ... 4 5 6 7 8 9 2.9 3.1 124,000 126,000 123,000 120,000 117,000 115,000 117,000 118,000 117,000 138,000 184,000 232,000 244,000 254,000 248, 000 228,000 214,000 181,000 180,000 174,000 174,000 175, 000 188,000 10 11 12 13 14 2.2 2.4 2.5 2.4 4.0 7.2 10.4 11.2 11.9 11.5 10.1 9.2 7.0 6.9 6.5 6.5 6.6 7.5 15 16 17 18 19 20 21 22 23 24 25 26 27 28 2Q 30 .^1 Mean dis- 169,000 1.39 1.19 254,000 115,000 A 184,000 1.51 1.68 210,000 166,000 A 178,000 1.46 1.68 211,000 158,000 A 139,000 1.14 1.31 160,000 108,000 A 106,000 0.869 0.97 146,000 78,000 A Second- feet per square mile Run-off (deptii in inch- es on drainage Maximum Minimum Accuracy 42913°— wsp 342—15 5 66 SUEFACE WATER SUPPLY OF YUKON-TAKANA REGION, ALASKA. Daily gage height, in feet, and discharge, in second-feet, of Yukon River at Eagle, Alaska, for 1911-12— Continued. May. June. July. August. September. October. Day. Gage height. Dis- charge. Gage hei^t. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage heignt. Dis- charge. 1912. 1 10.2 10.2 10.2 9.4 7.8 5.9 4.5 3.3 2.6 2.5 2.5 2.7 3.1 3.5 3.8 4.1 6.2 7.0 6.8 6.3 5.7 5.4 6.0 7.0 7.1 7.1 6.2 5.5 4.8 4.0 229,000 229,000 229,000 217,000 193,000 165,000 146,000 129,000 120,000 118,000 118,000 121,000 126,000 132,000 136,000 140,000 169,000 181,000 178,000 171,000 162,000 158, 000 166, 000 181,000 182,000 182,000 169,000 160,000 150,000 138,000 3.7 3.5 3.0 2.8 2.8 3.2 4.0 4.8 4.8 *"""3.'8 3.7 3.5 3.2 3.0 2.8 2.8 2.8 3.2 4.3 6.0 6.2 5.8 5.4 7.1 10.0 10.9 8.0 134,000 132,000 125,000 122,000 122,000 128,000 138,000 150,000 150,000 147,000 144,000 141,000 138,000 136,000 134,000 132,000 128,000 125,000 122,000 122,000 122,000 128,000 143,000 167, 000 169,000 164,000 158,000 182,000 226,000 240,000 196,000 7.5 6.5 6.1 5.0 4.5 4.2 3.9 4.7 4.0 3.7 3.2 4.5 4.7 5.7 5.0 3.0 2.8 2.2 2.0 2.0 1.9 1.7 1.4 1.2 .8 188,000 174,000 168,000 152,000 146,000 141,000 137,000 148, 000 138,000 134,000 128,000 146,000 148, 000 162,000 152,000 125, 000 122, 000 115,000 112,000 112,000 111,000 110,000 106,000 103,000 98,300 97,000 95,500 94,500 93,000 92,000 90,500 "-6.'2 "- .5 '"-i.'s "-2." 6 -2.1 -2.2 -1.5 ""-i."6 "-2." 6 89,000 87,300 85,500 84,000 82,000 80,000 78,000 77,000 76,000 74,000 72,000 70,000 69,000 68,000 67,100 66,200 73,000 76,000 78,500 76,000 74,000 72,000 70,000 68,000 67,000 66,500 66,000 65,500 65,000 64,500 "-2." 5 "'-3.'6 -4.0 64,000 2 63,500 3 62,000 59,000 58,000 4 5 6 57,000 7 56,000 8 55,000 9 54,000 53,000 52,500 10 11 12 52,000 13 51,500 14 51,000 15 50,500 50,000 16 17 49,500 18 49,000 19 48,500 20 21 22 3.6 3.4 3.2 3.5 3.7 4.5 5.2 6.4 7.1 7.9 8.8 9.8 133,000 130,000 128,000 132, 000 134,000 146,000 155,000 172,000 182,000 194, 000 208,000 223, 000 48,000 47,500 23 24 25 26 27 28 29 30 31 Mean dis- charge. . 161,000 1.32 0.59 223,000 128,000 A 160,000 1.32 1.47 229,000 118,000 A 147,000 1.20 1 38 240,000 122,000 A 127,000 1.04 1.20 188,000 90,500 A 73,600 0.603 0.67 89,000 64,500 A 53,900 Second- feet per square mile 0.442 Run-off (depth in inch- es on drainage area) . . 0.35 Maximum Minimum Accuracy- 64,000 47,500 A a Ice commenced running. YUKON RIVER AT RAMPART. A cross section and a discharge measurement were obtained on May 1, 1909, just above the mouth of Rampart Creek, which is a small tributary from the south at the lower end of the town of Ram- part. The bed is thought to be semipermanent and the channel is straight for at least 1,000 feet above and below the point of measure- ment. The banks on each side are high, with long gentle slopes. The left slope is of cemented gravel and bowlders; the right is of small gravel and is liable to slight changes. At the time the cross section was made the ice varied in thickness from 4 to 4-| feet, which was probably the maximum for the winter. The width of the sec- tion at the highest level of the ice was 1,560 feet, and its width at the water's surface was 1,300 feet, so that for 250 feet the ice was in FOKTYMILE RIVER DRAINAGE BASIN. 67 contact with the bed. The stage of the river at the time of the first ice cover ui the fall was considerably higher than at the time of the measurement, and as the water lowered its width decreased and the ice sheet fell, coming into contact with the previously submerged sloping bank. The greatest depth of water below the bottom of the ice was found to be 15.9 feet at a distance of 420 feet from the left edge of the ice. On May 19 and 21, 1909, two float measurements were made by timing ice cakes over a 500-foot range. The distance of the ice cakes from the shore was estimated, but it is believed no large error was introduced by this, for the velocity and section were very uniform. The measurements are considered to be only approximate. The stage was considerably above the mean for the summer. Discharge measurements of Yukon River at Rampart, 1909. Date. Width. May 1 May 19 May 21 Feet. 1,360 1,750 1,750 Area. Sq.ft. 11,700 58, 100 58, 500 Mean velocity. Ft. pr. sec. 0.93 6.32 6.31 Dis- charge. Sec.-ft. 10,900 367, 000 369, 000 Gage height. Feet. 51.6 80.9 81.1 Drainage area. Sq. mi. 206, 000 206,000 206, 000 Discharge per square mile. Sec.-ft. 0.05 1.78 1.79 a Bottom of the ice. FIFTYMILE RIVER AT WHITEHORSE, YUKON TERRITORY. Since 1902 the White Pass & Yukon Railroad Co. has kept daily records of the stage of Fiftymile River at Whitehorse and of the dates of opening and closing of navigation. In the spring of 1908 members of the United States Geological Survey, on their way to the interior of Alaska, made the following measurements of the river at this point: Miscellaneous measurements of Fiftymile River at Whitehorse, Yukon Territory, 1908. Date. Gage height. Discharge. Drainage area. Discharge per square mile. June 10 Inches. 16| Sec.-ft. 4,490 5,100 Sq. miles. 7,630 7,630 Sec.-ft. 0.588 June 16 .668 FORTYMILE RIVER DRAINAGE BASIN. DESCRIPTION. Fortymile River is tributary to Yukon River in the Yukon Territory at longitude 140° 30' west and latitude 64° 30' north, about 50 miles below Dawson, Yukon Territory, and about the same distance above Eagle, Alaska. The main river rises in Alaska and enters Canadian territory about 23 miles above its moutli. Some of its southern tribu- taries also rise hi Canadian territory. Of its total drainage area of 68 SURFACE WATER SUPPLY OF YUKON-TANANA REGION, ALASKA. 6,350 square miles, about 4 per cent lies in Canadian territory. The area is roughly fan-shaped, the extreme diametric dimensions being approximately 100 miles. The stream flow is predominantly from west to east. About 40 miles in an air line from its mouth the river divides into North and South forks, and again these subdivide some- what symmetrically into other forks. These tributaries will be described more in detail on later pages. On the north the tributaries interlock with those of Mission Creek and Seven tymile and Charley rivers in high, rocky ridges, of which Glacier Mountain is the most prominent. From the west Good- paster, Volkmar, and Healy rivers take the adjoining drainage from mountains equally rugged. In the southeast the streams head in a country of relatively low relief at a distance of only a few miles from Tanana River. Ladue Creek and Sixtymile River form the opposing drainage on the east and southeast, the moderately low dividing range being accentuated by several large dome-shaped mountains. A prominent feature of the lower Fortymile basin is the well-defined bench which marks the elevation of an earlier valley floor. In the vicinity of Steel Creek this bench is about 500 feet above the stream bed. The planes of the present and of the older valley floors coincide near the mouth of Kechumstuk Creek at an elevation of about 2,000 feet above sea level. A view of the Fortymile Valley just below Steel Creek is shown in Plate V, B. MAIN STEM OF FORTYMILE RIVER. DESCRIPTION. The main stem of Fortymile River, as determined by the area of drainage, consists of sections named in downstream order Dennison Fork, South Fork, and Fortymile River, Dennison Fork joining Mosquito Fork to form the South Fork. Dennison Fork has its source in a country characterized by wide swampy valleys which slope gently into fairly high mountains. The ridge separating its drainage from that of Tanana River parallels the Tanana at a distance varying from 4 to 10 miles. Its drainage area of 1,540 square miles is about equally divided between two forks which unite to form the main stream about 12 miles above its mouth. DENNISON FORK AT MOUTH. This station was located about one-half mile above the junction with Mosquito Fork, one-half mile below the mouth of a small tributary from the right known as Deep Creek, and 2^ miles south of Chicken post office. A gage was instaUed and one discharge measurement was made in 191-1. This gage was carried out by the high water of June 17, 1912, and a second was installed by the observer on June 19, all portymile river drainage basin. 69 1912 measurements being referred to the latter. The relation between the two gages was determined approximately from the 1911 measure- ment and all gage readings before June 17 were reduced to the datum of the 1912 gage. The drainage area of Dennison Fork is nearly one-fourth that of Fortymile River at the mouth: Some prospecting has been done in its basin, but no attractive discoveries have been made and there are practically no settlers in the entire area. The meager records give some idea of the character of its flow. It is believed that the run-off for June, 1912, was abnormally large and that the dis- charge of 6,500 second-feet on June 17 is nearly the maximum for this stream. It is estimated that the minimum summer discharge is less than 100 second-feet. Discharge measurements of Dennison Fork at mouth, 1911 and 1912. Date. Dis- charge. 1911 Aug. 23 1912 July 9 - Aug. 15 Aug. 16 Sec-ft. 139 203 807 625 Daily gage height, in feet, and discharge, in secondfeet, of Dennison Fork at mouth, for 1912. [Drainage area, 1,540 square miles. Observer, J. V. Anderson.] June. July. August. Day. June. July. August. Day. 1 s. O 6 o en s 4J o 6 O CO s '3 .d 03 bc 03 o 03 bO k^ 03 .d o .J9 ft 1912. 1 1912— Con. 16 2 1 17 . 1 3 1 18 , 4 1 19 5 2: 60 25 20 6 2.40 8 1 21 7 i ' 22 8 23 23 9 24 10 2.55 20 25 ... 11 26 12 2.50 16 27 13 28 14 29 15 '. . . 30 .... 31 WALKER FORK ABOVE TWELVEMILE CREEK. A gaging station was established on Walker Fork, li miles above Twelvemile Creek, on July 3, 1910, and gage-height records were obtained for about two months. The station could not be maintained in 1911 or 1912 because no observers were available. The record is of value as showing the characteristics of run-off of a typical Alaskan stream. FORTYMILE RIVER DRAINAGE BASIN. Discharge measurements of Walker Fork above Twelvemile Creek, 1910. 85 Date. Gage height. Dis- charge. July 3 Feet. 2.28 2.25 2.00 2.25 2.33 Sec.-ft. 33 4 30 Aug. 2 15 18 29 19 35 Daily gage height, in feet, and discharge, in second-feet, of Walker Fork above Twelvemile Creek for 1910. [Drainage area, 70.2 square miles. Observer, J. T. Dickinson.] July. August. Day. July. August. Day. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. 1 2.25 2.00 1.90 1.90 1.85 1.80 ""3." so" 3.00 2.60 2.40 2.30 '"2A0 '""2." 25' 2.25 2.20 2.20 30 15.0 11.3 11.3 10.0 8.7 10 54 242 114 01 41 33 26 20 25 30 30 26 26 21 22 2.10 2.25 2.30 2.35 2.20 2.10 2.00 1.95 2.20 2.25 2.25 20 30 33 37 26 20 15.0 13.2 26 30 30 ""'2." 20" 2.25 2.25 2.20 2.20 26 2 26 3 2.30 2.25 2.22 2.50 2.35 2.20 2.15 33 30 27 51 37 26 23 26 30 26 46 33 41 26 23 23 26 15.0 23 30 4 24 30 5 25 26 6 26 26 7 . . . 27 8 28 9 29 10 30 2.25 2.20 2.45 2.30 2.40 2.20 2.15 2.15 2.20 2.00 31 11 Mean dis- charge... 12 28.4 0.405 0.44 51 13.2 A _ 13 38. 14 Second-feet per square mile 15 0.541 16 Run-ofE (depth in inches on drainage area) . Maximum 17 0.52 18 242 19 Minimum 8.7 20 Accuracy B WADE CREEK AT CLAIM "NO. 10 ABOVE." This station is located about 8 miles above the mouth of Wade Creek, one-half mile above Jack Wade post office, at claim "No. 10 above." It was established July 4, 1910, and maintained for three seasons, the gage being relocated in 1911. It was impossible to determine by measurements the high-water rating, but it is believed that the rating determined by the curve extensions is fairly accurate. Wade Creek has been an important gold producer in the Fortymile district. Ordinary open-cut and drifting methods have been used, and a number of ditches have been constructed for bringmg the water to the claims at a suitable elevation for working. Frequently during the summer the water supply has been inadequate for continuous mining. Especially was this true in 1911, when mining operations were at a standstill for most of the season because of the very small flow. 86 SURFACE WATER SUPPLY OF YUKON-TANANA REGION, ALASKA. Discharge measurements of Wade Creek at claim ''No. 10 above, " 1910-1912. Date, Gage height. Dis- charge. Date. Gage height. Dis- charge. July 4.. 1910. Feet. 1.54 1.42 2.24 2.07 2.33 1.67 Sec.-ft. 2.3 0.91 19 13 24.8 2.1 1911— Continued. Aug. 29 Feet. 1.70 2.06 1.67 2.19 2.06 Sec.-ft. 2.5 Aug. 2 1912. June 6 19 20 - 11.3 1911. July 6 .87 Aug. 10 : 15.2 June 3 . . 21 11.4 July 21 Daily gage height, in feet, and discharge, in second-feet, of Wade Creeh at claim "No. 10 above'' for 1910-1912. [Drainage area, 23.1 square miles. Observer, J. P. Carroll.] July.a August. September. Day. July.o August. September. Day. bo 'ffl C3 0) %^ O ft 03 O 03 ft 4^ is 1 i s o 03 O o5 be o ft S bO 03 rd o ■4-J .d _bO 'S ,C| -Con. 21 4.0 6.5 9.0 7.0 5.2 3.5 1.7 2.5 3.2 4.0 3.0 2.08 2.17 1.92 2.08 2.67 2.33 2.42 2.33 2.08 2.08 2.00 13.4 16.4 8.8 13.4 40 23 27 23 13.4 13.4 11.0 2.00 2.00 2.08 2.00 1.92 2.17 2.08 2.08 1.92 1.92 11.0 2 1.42 1.42 1.42 1.50 1.42 1.50 2.50 4.08 3.50 2.00 2.17 2.00 2.04 1.92 2.42 2.33 2.25 2.25 2.08 22 11.0 3 23 13.4 4 1.54 2.1 5.5 8.8 7.4 6.0 4.5 3.0 6.5 10.0 13.0 16.4 5.0 10.0 7,5 9.0 5.2 1.5 24 11.0 5 25 8.8 6 1.92 26 16.4 7 27 1.50 13.4 8 28 13.4 9 29 8.8 10 30 8.8 31 11 Mean dis- charge. . 12 6.11 0.264 0.27 16.4 1.5 C 20.0 0.866 1.00 125 1.1 B 13 13.1 14 2.17 Second-feet per square mile 15 0.567 16 R un- f f (depth in inches on d r ataage area) . . 17 18 19 20 0.63 Maxi'mnm 19.5 Minimum. . 8.8 Accuracy. . . A o Daily discharges for the greater portion of July are estimated by comparative hydrographs and are only approximate. FORTYMILE RIVER DRAINAGE BASIN. 87 Daily gage height, in feet, and discharge, in second-feet, of Wade Creek at claim "iVb. 10 above'' for 1910-1912— Continued. June. July. August. September. October. Day. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. 1911. 1 1.67 1.67 1.67 1.67 1.84 2.08 1.84 1.75 1.71 1.75 1.84 1.79 1.75 1.71 2.75 1.92 1.84 1.75 1.67 1.67 1.67 1.67 1.67 1.84 1.75 1.84 1.92 1.75 1.75 1.67 1.67 2.3 2.3 2.3 2.3 5.2 12.1 5.2 3.5 2.9 3.5 5.2 4.2 3.5 2.9 3.5 7.1 5.2 3.5 2.3 2.3 2.3 2.3 2.3 5.2 3.5 5.2 7.1 3.5 3.5 2.3 2.3 1.67 1.67 1.67 1.75 1.75 1.67 1.67 1.58 1.58 1.50 1.84 1.84 1.84 1.92 1.84 1.92 1.92 1.84 1.84 1.75 1.75 1.67 1.67 1.67 1.67 1.67 1.75 1.67 1.67 1.84 1.84 2.3 2.3 2.3 3.5 3.5 2.3 2.3 1.3 1.3 .6 5.2 5.2 5.2 7.1 5.2 7.1 7.1 5.2 5.2 3.5 3.5 2.3 2.3 2.3 2.3 2.3 3.5 2,3 2.3 5.2 5.2 1.84 1.84 1.84 1.84 1.75 1.75 1.67 1.67 1.67 1.75 1.75 2.25 2.33 2.17 2.17 2.17 2.00 1.75 1.75 1.75 1.84 1.84 1.84 1.92 1.92 2.00 2.67 2.17 2.17 2.08 5.2 5.2 5.2 5.2 3.5 3.5 2.3 2.3 2.3 3.5 3.5 19.8 24 15.7 15.7 15.7 9.5 3.5 3.5 3.5 5.2 5.2 5.2 7.1 7.1 9.5 45 15.7 15.7 12.1 2.08 2.17 2.08 2.00 2.00 1.84 1.92 1.84 1.75 1.75 1.75 1.67 1.67 1.67 1.67 1.67 1.75 1.75 12.1 2 15.7 3 2.25 2.42 3.25 2.58 2.42 2.25 2.17 2.25 2.17 2.17 2.17 2.08 2.08 2.00 2.00 2.00 2.92 2.92 1.84 1.88 1.84 1.75 1.67 1.50 1.67 1.75 1.67 1.67 19.8 30 79 39 30 19.8 15.7 19.8 15.7 15.7 15.7 12.1 12.1 9.5 9.5 9.5 7.1 7.1 5.2 6.1 5.2 3.5 2.3 .6 2.3 3.5 2.3 2.3 12.1 4 9.5 5 9.5 6 5.2 7 7.1 8 5.2 9 3.5 10 3.5 11 3.5 12 2.3 13 2.3 14 2.3 15 2.3 16 2.3 17 3.5 18 3.5 19. 20 21 22 24 25 26 27 28 29 30 31 Mean discharge. Second-feet per square mile 14.3 0.619 0.64 79 0.6 B 3.9 0.169 0.19 12.1 2.3 B 3.6 0.156 0.18 7.1 0.6 C 9.3 0.403 0.45 45 2.3 B 5.8 0.251 Run-ofi (depth in inches on drainage area) 0.17 Maximum 15.7 2.3 Accuracy B 88 SURFACE WATER SUPPLY OF YUKON-TANANA REGION, ALASKA. Daily gage height, in feet, and discharge, in second-feet, of Wade Creek at claim "No. 10 above'' for 1910-1912— Continued. June. July. Aug ust. September. October. Day. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge, Gage height. Dis- charge. Gage height. Dis- charge. 1912. 1 1.67 1.58 1.50 1.42 1.33 1.67 1.67 1.67 1.67 1.58 1.67 1.67 1.67 1.75 1.75 1.83 1.83 1.83 1.67 1.67 1.75 2.65 2.60 2.33 2.17 2.00 2.00 1.92 1.92 1.83 1.83 1.0 .8 .8 .8 .8 1.0 1.0 1.0 1.0 .4 1.0 1.0 1.0 2.3 2.3 4.2 4.2 4.2 1.0 1.0 2.3 36 34 21 15 9.3 9.3 6.9 6.9 4.2 4.2 2.17 2.67 2.00 2.00 1.92 2.33 2.65 2.65 2.08 2.17 3.15 3.50 3.35 3.35 2.65 2.33 2.25 2.17 2.25 2.17 2.25 2.08 2.04 2.04 2.00 2.04 2.17 2.21 2.17 2.17 2.17 15 38 9.3 9.3 6.9 21 36 36 12 15 68 96 84 84 36 21 18 • 15 18 15 18 12 10 10 9.3 10 15 16 15 15 15 2.04 2.00 2.00 2.00 2.00 2.00 2.17 2.17 2.08 2.17 2.08 2.08 2.08 2.08 2.08 2.00 2.50 3.50 2.65 2.85 2.50 2.50 2.50 2.42 2.25 2.25 2.17 2.17 2.12 2.50 10 9.3 9.3 9.3 9.3 9.3 15 15 12 15 12 12 12 12 12 9.3 29 96 36 48 29 29 29 25 18 18 15 15 13 29 2.42 2.42 2.33 2.33 2.25 2.25 2.17 2.33 2.33 2.29 2.29 25 2 25 3 21 4 21 5 18 6 2.04 2.04 2.00 2.00 2.00 1.83 1.75 2.33 2.25 2.33 2.83 2.33 2.25 2.33 2.33 2.25 2.17 2.33 2.42 2.33 2.25 2.00 2.00 1.75 1.75 10 10 9.3 9.3 9.3 4.2 2.3 21 18 21 47 21 18 21 21 18 15 21 25 21 18 9.3 9.3 2.3 2.3 18 7 15 8 21 9 21 10 20 11 20 12 13 14 15 16.. 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Mean discharge. 15.3 0.662 0.62 47 2.3 B 5.8 0.251 0.29 36 0.4 B 25.7 1.11 1.28 96 6.9 B 20.4 0.883 0.99 96 9.3 B 20.5 Second-feet per square mile 0.887 Hun-off (depth in inches on drainage area) 0.36 Maximum 25 Minimum 15 Accuracy B BUCKSKIN CREEK ABOVE FORTYFIVE PUP. Scattered gage-height records were obtained on Buckskin Creek just above the mouth of Fortyfive Pup during 1910, 1911, and 1912. The basin of Buckskin Creek above Fortyfive Pup is similar to that of Fortyfive Pup, and the characteristics of its flow are probably the same. The records for Fortyfive Pup are more continuous and may be found below : FORTYMILE RIVER DRAINAGE BASIN. 89 Discharge measurements of BucJcsHn Creek above Fortyjive Pup, 1910-1912. Date. Gage height. Dis- charge. Date. Gage height. Dis- charge. July 11.. 1910. Feet. 0.50 .86 .58 1.36 .50 .79 .46 Sec.-ft. 4.3 12.7 5.2 45.9 6.0 14.4 5.2 June 12.. July 15.. Aug. 17.. 20.. 1912. Feet. 0.79 .46 1.00 .92 Sec.-ft. a 13.6 Aug. 11 3.0 21 24.0 1911. 20.9 June 2 . . July 10 15 Aug. 21 a Measurement made by floats. Daily gage height, in feet, and discharge, in second-feet, of Buchskin Creek above Forty five Pup for 1910-1912. [Drainage area, 33 square miles. Observer, L. G. Michaels.] July. August. September. Day. July. August. September. Day. s -Con. 21 1.50 1.67 1.62 1.58 1.54 1.50 1.50 1.46 1.46 1.42 1.42 0.8 2.3 1.7 1.3 1.0 .8 .8 .7 .7 .6 .6 1.67 1.62 1.58 1.62 1.62 1.58 1.67 1.62 1.58 1.58 1.62 2.3 1.7 1.3 1.7 1.7 1.3 2.3 1.7 1.3 1.3 1.7 2 22 3 23 4 24 5 25 6 26 7 27 8 28 9 29 10 30 1.60 1.66 1.72 1.68 1.64 1.60 1.64 1.60 1.4 2.2 3.1 2.4 1.9 1.4 1.9 1.4 1.0 .7 31 11 Mean dis- charge.. 12 1.37 0.151 0.12 3.1 0.6 A 4.98 0.547 0.63 63 0.6 C 13 1.53 14 Second-feet per square mile 15 0.168 16 R un-off (depth in inches on drainage area) . . . 17 18 19 20 1.46 0.07 Maximum . . 2.3 Minimum. . Accuracy . . . 1.3 A 92 SURFACE WATEB SUPPLY OF YUKON-TANANA EEGION, ALASKA. Daily gage height, in feet, and discharge, in second-feet, of Forty five Pup at claim No. IS for 1910-1912— Gontimied. May. Jime. July. August. September. October. Day.^ Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. 1911. 1 2.00 1.92 1.92 1.92 2.08 2.00 1.92 1.83 1.75 1.75 1.67 1.75 1.83 1.92 2.00 1.92 2.17 2.00 1.83 1.75 1.75 1.67 1.67 1.67 1.67 1.67 1.58 1.58 1.58 1.58 18.6 '13.2 13.2 13.2 24 18.6 13.2 7.4 5.5 5.5 3.5 5.5 7.4 13.2 18.6 13.2 30 18.6 7.4 5.5 5.5 3.5 3.5 3.5 3.5 3.5 1.8 1.8 1.8 1.8 1.58 1.58 1.58 1.58 1.58 1.54 1.54 1.50 1.50 1.50 1.58 1.54 1.54 1.58 1.67 1.58 1.54 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.54 1.75 1.75 1.71 1.67 1.62 1.8 1.8 1.8 1.8 1.8 1.3 1.3 .7 .7 .7 1.8 1.3 1.3 1.8 3.5 1.8 1.3 .7 .7 .7 .7 .7 .7 .7 .7 1.3 5.5 5.5 4.4 3.5 2.5 1.58 1.58 1.54 1.67 1.67 1.62 1.58 1.58 1.54 1.54 1.67 1.67 1.62 1.62 1.71 1.71 1.67 1.67 1.62 1.67 1.58 1.54 1.54 1.54 1.50 1.50 1.50 1.50 1.50 1.50 1.62 1.8 1.8 1.3 3.5 3.5 2.5 1.8 1.8 1.3 1.3 3.5 3.5 2.5 2.5 4.4 4.4 3.5 3.5 2.5 3.5 1.8 1.3 1.3 1.3 .7 .7 .7 .7 .7 .7 2.5 1.62 1.62 1.58 1.58 1.58 1.54 1.54 1.50 1.50 1.54 1.75 1.96 1.92 1.79 1.75 1.71 1.67 1.67 1.67 1.67 1.62 1.67 1.67 1.67 1.71 1.71 1.75 1.75 1.75 1.79 2.5 2.5 1.8 1.8 1.8 1.8 1.3 .7 .7 1.8 5.5 15.9 13.2 6.6 5.5 4.4 3.5 3.5 3.5 3.5 2.5 3.5 3.5 3.6 4.4 4.4 5.5 5.5 5.5 6.6 1.83 7.4 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 2.46 2.25 53.4 36.6 31 Mean dis- charge. . 9.52 1.05 1.17 30 1.8 B 1.8 0.198 0.22 5.5 0.7 A 2.2 0. 242. 0.27 4.4 0.7 A 4.2 0.461 0.51 15.9 0.7 A Second-feet per square mile . . Run-off (depth in inches on drainage area) Maximum ..... MiniTtinm ... Accuracy FORTYMILE RIVER DRAINAGE BASIN. 93 Daily gage height^ in feet, and discharge, in second-feet, of Forty five Pup at claim No. 13 for 1910-1912— Qoniumed. May. June. July. August. September. October. Date. Gage height. Dis- charge. Gage Dis- height. charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dij- charge. 1912. 1 2.95 3.20 2.80 32 49 23 20 20 18 18 16 16 14 14 14 12 35 46 77 77 77 70 74 40 35 30 24 60 74 40 21 14 8 '"2.'i6" "i'io" 2.60 2.85 2.60 2.50 2.40 2.35 6 I 4 4 4 2 2 2 2 2 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.8 24 40 24 18 12 10 8 8 6 4 4 2.15 2.50 2.60 2.55 2.90 3.15 2.65 2.55 2.50 3.90 3.00 2.65 2.60 2.55 2.45 2.35 2.35 2.30 2.25 2.25 2.20 2.20 2.15 2.15 2.9 18 24 21 30 43 60 27 21 18 118 50 27 24 21 15 . 10 10 8.0 6.0 6.0 4.0 4.0 2.9 2.9 2.9 4 4 4 4 4 2 3 4 5 6 7 2.60 2.60 2.60 2.60 2.80 2.95 3.10 3.20 3.30 3.10 3.05 2.95 2.95 2.80 2.90 2.90 2.80 2.75 2.70 2.70 2.60 2.80 3.15 2.90 2.70 12 12 12 12 23 32 42 49 56 42 38 32 32 23 29 29 23 20 17 17 12 23 46 29 17 "'2.' 65' 2.60 3.00 3.15 3.60 "'3.' 60' 3.50 3.35 2.85 "'2.' 60' 3.15 3.35 2.85 2.55 8 9 10 11 12 13 14 15 16 17 18 2.50 IS 19 20 21 . . 22 1 23 1... 24 ! 25 26 27 28 29 i 30 1 31 Mean dis- charge. . 27.2 2.99 2.78 56 12 C 35.6 3.91 4.36 77 8 C 6.8 0.747 0.86 40 1.8 B 19.2 2.11 2.43 118 2.9 B Second-feet per square mile . Run-off (depth in inches on drainage area) Max'TnuTn j MinfTnum 1 Accuracy 1 1 i 94 SUEFACE WATER SUPPLY OF YUKON-TANANA REGION, ALASKA. MISCELLANEOUS MEASUREMENTS. The following miscellaneous discharge measurements were made in South Fork of Fortymile drainage basin in 1910 to 1912: Miscellaneous measurements in South Fork of Fortymile River drainage basin, 1910-1912. Date. Stream. Tributary to — Locality. Dis- charge. Drain- age area. Dis- charge per square mile. Aug. 16,1912 Deep Creek Mosquito Fork do Dennison Fork South Fork do Above ditch intake Mouth Sec.-ft. 0.24 314 193 198 169 2.0 a. 8 41.9 20.8 1.3 1.86 1.5 1.2 1.81 1.1 .86 .65 .40 .60 7.79 41.1 Sq. mi. Sec.-ft. July 17,1911 1,120 1,120 1,120 1,120 57.7 16.3 406 414 3.1 3.1 1.5 1.5 50.0 13.3 13.3 13.3 13.3 13.3 13.3 73.7 28 July 20,1911 do 17 Aug. 23,1911 do do do 18 July 13,1912 Aug. 7,1910 July 15,1912 ..do do do 15 Gold Creek Chicken Creek Mosquito Fork do Above Willow Creek. . . Mouth .035 .049 July 7, 1912 Aug. 27,1911 Walker Fork do South Fork do Below Wade Creek Mouth .10 .050 July 2,1910 Poker Creek do Walker Fork do .42 July 6, 1912 do do .60 July 2, 1910 Davis Creek do 1 mile above mouth do 1.00 July 6, 1912 do do .80 July 7, 1912 Wade Creek do Mouth .036 July 5, 1910 Napoleon Creek . . . do South Fork do .083 July 11,1911 do do .065 July 21,1911 ... do do do .049 Aug. 27,1911 ... do do do .030 July 7,1912 .. do do do .045 Aug. 10,1912 . do .... do do .59 Aug. 21,1912 Buckskin Creek . do do .$6 a Discharge estimated. NORTH FORK OF FORTYMILE RIVER DRAINAGE BASIN. DESCRIPTION. North Fork drains an area of 2,120 square miles. The stream has its source in high rugged mountains 3,000 to 6,000 feet high. Near the headwaters the valleys are broad with gentle slopes, but nearer the mouth they become canyon-like with prominent benches which are merely continuations of those of the lower Fortymile River. The principal tributary and that representing the main stem of the stream is Middle Fork, locally known as Granite Fork. Its drainage area is 1,110 square miles, which is 52 per cent of the total drainage of the North Fork. Its headwaters drain a country with wide flat valleys somewhat similar to those of Mosquito and Dennison forks. North Fork above Middle Fork, locally known as Eureka Creek, has for its principal tributaries Slate, Comet, and Champion creeks. Below the junction of the two forks Bullion and Hutchinson creeks enter from the west. There are very few people in the North Fork basin, and it has been possible to obtain only very meager stream-flow records. Some min- ing has been done on tributaries of Slate Creek but has now been aban- doned. Hutchinson has also been the scene of mining and is still so to some extent. All mining in this basin is severely handicapped by its isolation from the source of supplies and by the very high cost of freighting. FOKTYMILE RIVER DRAINAGE BASIN. 95 Two power possibilities on the North Fork, one at the ^^kink" and another about a mile below the junction of the North and Middle forks, are described more in detail on page 329. NORTH FORK OF FORTYMILE RIVER AT THE "KINK." The ''khik" is on North Fork, about 12 miles above the junction of that stream with South Fork, 3 miles below the mouth of Hutch- inson Creek, and about 16 miles northwest of Franklin post office in an air line but nearly 40 miles by trail. A view of the ''kink" is shown m Plate IX, A, and it is described on page 329. A gage was installed at this point on July 15, 1910, and two discharge measure- ments were made during that season, but it was impossible to obtain gage-height records because no observer was available. On July 17, 1912, a second gage was installed at the same control. One discharge measurement was made and scattermg records of gage heights obtained. The discharge measurements are insufficient to rate the station; consequently only the results of the measurements and the record of the gage heights are pubfished. The daily discharge at the ^^kink" has been estimated from the records of Fortymile River at Steel Creek and the South Fork at Franklin. The drainage area of North Fork at the ''kink" is 74 per cent of Fortymile River at Steel Creek minus that of the South Fork at Franklin. Therefore 74 per cent of the difference between the discharges at Steel Creek and at Franklin will approximate the dis- charge at the "kink." The errors involved by this method are largely eliminated by taking the mean for a number of days. Discharge measurements of North Fork of Fortymile River at the "hinJc,^' 1910 and 1912. Date. 1910. July 15 Aug. 8 1912. July 17 Dis- charge. Sec.-ft. 897 425 541 Daily gage height, in feet, of North Fork of Fortymile River at the "kink" for 1912. [Drainage area, 2,010 square mUes. Observer, E. G. Kenhel.] Day. July. Aug. Day. July. Aug. Day. July. Aug. 1 11 6.5+ 6.5+ 21 4.45 2 12 22 3 13 23 4 14 6.15 5.95 5.25 '3.' 75' 3.85 24 5 2.25 15 25 6 16 26 7 a6.5+ 17 1.50 1.45 27 8 18 28 . 9 6.5+ 19 29 10 20 30 31 o Water reported over top of gage. Highest graduation on gage, 6.50. 96 SUEFACE WATER SUPPLY OF YUKON-TANANA REGION, ALASKA. Daily discharge, in second-feet, of North Fork of Fortymile River at the ''kink'' for 1910- 1912. Day. July. Aug. Sept. Day. July. Aug. Sept. 1910. 1 290 290 300 309 272 267 249 252 1,940 2,720 1,740 1,110 800 734 572 408 340 420 384 482 326 326 290 528 696 696 770 696 592 503 503 503 473 408 408 1,510 1,760 1,930 1,520 1,250 1910— Continued. 21 397 308 308 322 322 428 417 350 328 284 246 650 613 465 392 377 484 454 454 462 498 409 762 2 22 646 3 23 484 4 24 5 25 6 26 7 27 8 28 9 352 1,040 985 1,010 925 930 606 511 370 230 445 421 29 10 30 31 11 Mean discharge. . . . Second-feet per square mile 12 502^ 0.250 0.214 C 617 0.307 0.35 C 13 817 14 0.406 15 Run-off (depth in inches on drainage area) Accuracy 16 0.35 17 C 18 19 20 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. Day. 1911. May. 19,500 18,500 June. 10,200 6,840 7,470 7,130 6,500 8,560 7,360 4,490 3,970 3,610 3,110 2,330 3,260 2,270 2,390 3,630 3,170 3,240 2,690 2,040 July. 755 755 592 1,600 2,150 4,950 3,710 2,200 1,770 1,040 747 600 448 296 o800 1,100 873 a 500 488 781 Aug. 318 219 185 226 226 226 226 218 182 163 245 502 866 478 507 847 1,630 1,260 1,170 1,050 Sept. 725 666 607 548 533 518 518 503 488 466 643 977 1,455 1,310 1,220 1,050 773 544 363 296 Day. 1911— Con. 21 22 23 24 25 26 27 28 29 30 31 Mean dis- charge.. Second -feet per square mile R u n - o f f (depth i n inches o n drainag«e area) Accuracy May. 7,400 4,450 2,220 2,100 3,920 7,100 6,970 5,060 5,350 5,160 9,620 7,540 3.75 1.81 C June. 1,590 2,150 1,110 995 1,010 903 792 792 940 755 3,510 1.75 1.95 C July. 444 724 936 892 544 507 535 913 976 592 414 1,080 0.537 0.62 C Aug. 788 566 505 359 341 318 302 307 307 307 307 489 0.243 0.28 C Sept. 710 0.353 0.26 C 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. Day. 1912. May. 1,540 1,680 2,020 2,520 2,220 3,420 2,320 3,110 3,510 5,570 4,140 4,310 4,180 4,990 3,940 2,400 June, 3,140 3,000 6,510 4,090 2,870 1,820 1,270 888 836 1,220 1,550 1,250 4,030 5,820 3,040 9,950 13,900 13,000 10, 100 10, 100 July, 1,380 1,010 1,470 1,580 1,300 932 711 563 511 514 577 703 755 792 829 688 570 525 496 Aug. 644 1,070 1,230 1.100 '851 618 435 8,140 2,020 1,420 2,600 9,910 5,100 1,920 1,710 1,360 1,050 1,130 1,820 1,900 Sept. 1,110 1,150 1,110 1,020 1,150 1,150 777 733 600 725 962 873 651 637 766 736 1,180 2,570 2,180 Oct. 733 770 814 740 666 696 725 681 607 574 570 540 481 Day. 1912— Con. 21 22 23 24 25 26 27 28 29 30 31 Mean dis- charge.. Second-feet per square mile Run-off (depth in inches on d r ainage area) Accuracy... May. 2,400 2,720 2,920 2,640 1,360 1,060 755 940 3,310 7,620 5,570 3,240 1.61 1.62 C June, 8,000 5,520 6,070 6,070 4,280 4,770 3,610 2,520 1,370 1,210 4,740 2.36 2.63 C July. 525 3,230 2,310 1,370 1,070 1,020 1,320 1,490 1,200 918 666 1,060 0.527 0.61 C Aug. 1,900 1,810 1,500 1,400 1,500 1,350 1,210 1,860 1,580 1,450 1,160 2,150 1.07 1.23 C Sept. 1,780 1,380 1,180 1,060 903 555 452 341 341 385 1,010 0.503 0.56 C Oct. 661 0.329 0.16 C o Discharges interpolated. FOKTYMILE EIVEE DBAINAGE BASIN. 97 NORTH FORK OF FORTYMILE RIVER ABOVE MIDDLE FORK. This station was located at the North Fork telegraph station of the Signal Corps of the United States Army, about a mile above the mouth of the Middle Fork and about 40 miles southwest of Eagle in an air line. The station was established July 15, 1910, and gage- height observations were made for the remainder of the summer. The telegraph station was abandoned by the Signal Corps in the winter of 1910-11, making it impracticable to continue stream-flow records at this point. Discharge measurements of North Fork of Fortymile River above Middle Fork, 1910-1912. Date. 1910. July 16 17 Aug. 22 23 Sept. 12.'".'.'..'.. Gage Dis- height. charge. Feet. Sec.-ft. 2.14 242 2.00 194 1.95 170 1.90 155 2.29 294 Date. Aug. 18. 1911. July 18. 1912. Gage height. Feet. Dis- charge. Sec.-ft. 1,060 250 Daily gage height, in feet, and discharge, in second-feet, of North ForTc of Fortymile River above Middle Fork for 1910. [Drainage area, 724 square miles. Observer, E. H. Lathrop.] July. August. September. October. Day. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height Dis- charge. 1 1.92 1.92 1.88 1.83 1.79 1.71 1.67 2.00 4.1 3.3 2.85 2.60 2.33 2.17 2.08 2.04 2.08 2.04 2.08 2.08 2.04 2.00 1.92 1.90 1.92 1.90 1.92 2.00 1.98 1.92 1.83 162 162 149 135 125 106 99 189 1.420 904 622 475 330 256 219 204 219 204 219 219 204 189 162 155 162 155 162 189 182 162 135 1.83 2.04 3.0 2.85 2.65 2.85 2.65 2.65 2.60 2.42 2.42 2.33 2.33 2.25 2.90 3.7 3.4 3.7 3.2' 2.90 2.60 "'2.' 33' 2.17 2.17 2.08 2.00 1.92 2.00 135 204 714 622 504 622 504 504 475 377 377 330 330 292 653 1,160 968 1,160 840 653 475 419 374 330 256 256 219 189 162 189 2.00 1.92 189 2 162 3 4 6 6 7 8 9 10 11 12 13 14 15 2.17 2.11 2.00 1.92 2.00 2.00 1.92 1.92 2.08 2.04 2.08 1.92 1.88 1.88 1.79 1.75 1.83 256 230 189 162 189 189 162 162 219 204 219 162 149 149 125 116 135 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 ... 31 Mean discharge 177 0.244 0.15 256 116 A 267 0.369 0.42 1,420 99 B 477 0.659 0.74 1,160 135 B Second-feet per square mile Run-off (depth in inches on drainage area) Maximum Minimum Accuracy 42913° — WSP 342—15- 98 SURFACE WATER SUPPLY OF YUKON-TANANA REGION, ALASKA. CONFEDERATE CREEK AT MOUTH. This station was located at the mouth of Confederate Creek, about 27 miles from Franklin post office. It was maintained for about a month in 1912. The drainage basin of Confederate Creek is some- what greater than that of Hutchinson Creek above Confederate but is very similar in character. The slow-melting glaciers and snow banks in the high rugged mountains in which the stream heads fur- nish a relatively good water supply. Discharge measurements of Confederate CreeJc at mouth, 1912. Date. height. Dis- charge. June 11. July 16. Aug. 18. Feet. 0.25 .83 Sec.-ft. a 4. 9 .73 14.8 a Measurement made by floats. Daily gage height, in feet, and discharge, in second-feet, of Confederate Creeh at mouth for 1912. [Drainage area, 9 square miles. Observer, E. M. Webster.] June. July. August. Day. June. July. August. Day. fciO O a5 ■s CO ft ® o ho C3 CO s 03 a5 Fh c3 1 s +-5 Of) .1— ( a5 o CO s 4J 3 CD W) O o CO p 4J (A u o CO s 1 0.75 .60 .55 11 6.4 5.1 5.1 5.1 15 40 24 11 7.9 57 50 24 18 16 16 11 16 16 21 0.65 .70 .65 .60 .60 .80 .65 .65 .60 .75 .80 7.9 9.4 7.9 6.4 6.4 13 7.9 7.9 6.4 11 13 2 22 3 23 4 .. . . 24 25 6 26 7 1.25 1.00 .75 .65 1.50 1.40 1.00 .90 .85 .85 .75 .85 .85 27..... 8 28 9 29 10 .. 30 4.9 31 11 Mean dis- charge. „ 12 6.95 0.772 0.46 13 2.8 B 13 18.7 14 Second -feet per square mile 15 0.40 .40 .40 .40 .40 2.8 2.8 2.8 2.8 2.8 2.08 16 Run-off (depth in inches on d r ainage area) 17 18 19 20 1.47 Maximum.. 57 Minimnm . _ 5.1 Accuracy B HUTCHINSON CREEK BELOW CONFEDERATE CREEK. A gage was installed on Hutchinson Creek, just below the mouth of Confederate Creek and about 27 miles by trail from Franklin post ofhce, on July 13, 1910, and scattering records were obtained during 1910 and 1911. During the summer of 1912 the gage-height records FOETYMILE EIVER DRAINAGE BASIN. 99 were practically continuous. The channel shifted somewhat during 1910 and 1911, but in 1912 the effect of shifts was probably negligible. Discharge measurements of Hutchinson Creek below Confederate Creek, 1910-1912. Date. Gage height. Dis- charge. Date. Gage height. Dis- charge. July 13 1910. Feet. 1.24 1.21 1.09 1.53 1.25 1.35 1.58 Sec.-ft. 7.3 5.8 1.7 35.0 3.9 4.50 7.12 1911- Aug. 20... -Contiuued. Feet. 1.42 1.50 1.42 1.73 Sec.-ft. 5.45 14 June 11 . . July 16.. 1912. Aug. 7.. 9.. n 8 2 21 . . - 4 47 1911. Aug. 18 25 3 July 13.. 14.. a Measurements made by floats. Daily gage height, in feet, and discharge, in second-feet, of Hutchinson Creek below Con- federate Creek for 1911-12. [Drainage area, 16.6 square miles. Observer, E. M. Webster.] July.- August. September. Day. July. August. September. Day. 4J 03 o s i o .S3 P t o .a p s o .a p 'S rd o o CO p o CO p 1911. 1 1911— Con. 16 1.84 26 2 17 3.. 18 4 -. . 19 5 .... 1.67 1.58 1.71 1.75 1.79 1.84 3.1 3.0 2.8 2.8 1.92 12 7.3 15 18 21 26 172 158 132 132 34 20 1.42 5.3 6. .. 21 7 ' 22 1.58 7.3 8.... 1 23 9 ... 24 1.50 6.3 10 25 2.7 120 11 26 12 27 13 1.33 1.58 4.3 7.3 28 14 29 1.42 5.3 15 30 1 31 1 1.50 6.3 1 1 1 100 SURFACE WATER SUPPLY OF YUKOI^-TAH^ANA REGION, ALASKA. Daily gage height, in feet, and discharge, in second-feet, of Hutchinson Creeh below Con- federate Creek for 1911-12 — Continued. May. June. . July. August. Day. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. 1912. 1 1.85 2.10 1.85 1.80 1.75 1.70 1.65 1.70 1.65 1.60 1.45 2.05 2.45 2.40 2.85 2.10 2.15 1.70 1.40 1.75 1.70 1.80 1.95 2.30 2.30 2.15 2.10 1.95 1.65 1.40 37 62 37 32 27 22 18 22 18 14 6.0 57 102 96 151 62 67 22 a 22 27 22 32 47 84 84 67 62 47 18 4.0 1.40 1.60 1.60 1.50 1.35 1.20 1.35 1.40 1.40 1.40 1.45 1.40 1.60 1.55 1.55 1.45 1.45 1.40 1.35 1.40 1.80 1.80 1.75 1.65 1.60 2.10 1.95 1.90 1.85 1.75 1.90 4.0 14 14 8.0 3.0 1.2 3.0 4.0 4.0 4.0 6.0 4.0 14 11 11 6.0 6.0 4.0 3.0 4.0 32 32 27 18 14 62 47 42 37 27 42 1.90 1.75 1.65 '"2." is' 2.00 1.90 1.85 2.65 2.00 1.90 1.85 1.75 1.75 1.85 1.75 1.75 1.75 1.75 1.85 1.85 1.75 1.75 1.85 1.90 42 2 27 3 18 4 18 5 18 6 30 7 67 8 52 9 42 10 37 11 126 12 " 52 13 42 14 37 15 27 16 27 17 37 18 27 19 27 20 27 21 27 22 37 23 1.90 1.80 1.95 2.10 2.30 2.15 2.15 1.95 1.85 42 32 47 62 84 67 67 47 37 37 24 27 25 27 26 37 27 42 28 35 29 35 30 35 1 35 Mean discharge 53.9 3.25 1.09 84 32 B 45.6 2.75 3.07 151 4.0 B 16.4 0.988 1.14 62 1.2 B 37.2 Second-feet per square mile 2.24 E,un-ofE (depth in inches on drainage area) 2.58 Maximum 126 Minimum 18 Accuracy , B a Discharge interpolated. HUTCHINSON CREEK BELOW MONTANA CREEK. On July 14, 1910, a gage was installed on Hutchinson Creek just below the mouth of Montana Creek and about 2 miles below the mouth of Hutchinson Creek. Occasional records were obtained for three seasons. Channel shifts necessitated the use of a different rating table for each season, but the errors due to this cause are probably not very great. The records at this station, with those below Con- federate Creek, give a fairly comprehensive idea of the flow of Hutchinson Creek. FOKTYMILE RIVER DRAINAGE BASIN. lOl Discharge measurements of Hutchinson Creek below Montana Creek, 1913-1912. Date. Gage height. Dis- charge. Date. Gage height. Dis- charge. July 14.. 1910. Feet. 1.44 1.27 2.33 1.33 Sec.-ft. 10.1 5.1 88.0 7.9 July 13.. 1911. Feet. 1.37 1.80 1.50 1.71 1.50 2.21 Sec.-ft. 7.71 Aug. 8 14 27.7 9 Aug. 20 11.6 22 June 11 . . 1912. a 10.5 July 16 7 49 Aug. 18 36 1 a Measurements made by floats. Daily gage height, in feet, and discharge, in second feet, of Hutchinson Creek below Montana Creek for 1910-1912. [Drainage area, 29 square miles. Observer, Jack McLin.] July. August. Day. July. August. Day. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. 1910. 1 1.23 1.21 1.21 1.21 1.19 1.19 1.19 2.21 2.33 4.5 4.1 4.1 4.1 3.7 3.7 3.7 73 88 78 69 51 51 51 51 51 44 37 30 23 1910— Con. 21 1.33 1.33 1.34 1.31 1.25 1.23 1.23 1.23 1.23 1.24 1.25 6.7 6.7 7.0 6.1 4.8 4.5 4.5 4.5 4.5 4.7 4.8 '"'i."38* "'"i.'54' 16 2 22 8.2 3 23 9.2 4 . 24 10.2 5 25 11.2 6 26 12.2 7 27 13.2 8 28 14.2 9 29 15.2 10 30 2.17 2.00 31 11 Mean dis- charge . . . 12 5.88 0.203 0.14 10.5 4.5 B 13 28.8 14 1.44 10.5 8.6 6.7 6.1 5.4 5.0 4.8 2.00 Second-feet per square mile 15 0.993 16 1.33 1.31 1.28 1.26 1.25 Run-ofl (depth in inches on drainage area). 17 1.07 18.. Maximum 88 19 Minimum 3.7 20 Accuracy c July. August. September. Day. July. August. September. Day. +3 .§ S (3 O 03 4J .£3 'S (D 03 O d 1 ft 'S A bf) ft 1 2.08 2.00 2.00 2.00 2.00 1.95 2.00 2.75 4.00 3.75 3.30 3.10 3.00 2.80 2.75 '2." 56' 2.15 2.25 2.20 2.25 2.35 2.40 2.45 9.6 6.8 6.8 6.8 6.8 5.7 6.8 72 348 288 181 137 116 80 72 62 50 39 12.6 18.0 15.0 18.0 25 29 34 2.25 2.25 2.25 2.50 2.50 2.20 2.20 2.50 2.50 2.60 2.65 2.75 2.75 2.75 2.80 2.85 2.85 2.90 3.00 18.0 18.0 18.0 39 39 15.0 15.0 39 39 50 57 72 72 72 80 88 88 97 116 26 2.10 2.15 2.05 2.00 2.05 2.05 10.3 12.6 8.6 6.8 8.6 8.6 2.50 2.55 2.20 2.05 2.15 2.25 39 44 15.0 8.6 12.6 18.0 2 2.13 2.10 2.10 2.15 2.45 2.75 2.15 2.15 2.15 2.15 2.45 2.9a 2.75 11.7 10.3 10.3 12.6 34 72 12.6 12.6 12.6 12.6 34 97 72 51 29 15.0 18.0 12.6 8.6 12.6 15.0 18.0 10.3 10.3 27 3 28 4 29 5 30 31 A Mean dis- charge.. 7 22.0 0.377 0.42 97 6.8 A 57.5 0.984 1.13 348 5.7 C 8 54.3 9 Second-feet per square mile 10 0.930 11 Run-off (depth in inches on d r ainage area) 12 13 14 15 0.66 2.40 2.20 2.25 2.15 2.05 2.15 2.20 2.25 2.10 2.10 Maximum.. 116 16 Minimum. . 15.0 17 Accuracy B 18 19 20 21 22 23 24 25 Discharge measurements of Canyon Creeh 2 miles below Squaw Gulch, 1911. Date. June 6 July 23 Aug. 31 Gage height. Feet. 3.10 2.00 2.62 Dis- charge. Sec.-ft. a 1.20 3.94 8.28 a Discharge estimated. FOETYMILE EIVER DRAINAGE BASIN. 115 Daily gage height, in feet, and discharge, in second-feet, of Canyon Creek 2 miles below Squaw Gulch for 1911. [Drainage area, 59.5 square miles.] June. July. August. September. Day. Gage Dis- height. charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. 1 2.50 2.46 2.50 2.58 2.50 2.50 2.46 2.46 2.46 2.58 3.12 2.79 2.75 2.75 2.84 2.92 2.84 2.84 2.75 2.67 2.67 2.58 2.58 2.58 2.54 2.54 2.54 2.54 2.54 2.58 2.67 7.2 6.9 7.2 7.9 7.2 7.2 6.9 6.9 6.9 7.9 13.5 9.8 9.4 9.4 10.3 11.0 10.3 10.3 9.4 8.7 8.7 7.9 7.9 7.9 7.6 7.6 7.6 7.6 7.6 7.9 8.7 2.67 2.67 2.58 2.58 2.58 2.54 2.54 2.54 8.7 2 8.7 3 7.9 4 7.9 5 2.60 3.10 8.1 120 7.9 6 . 7.6 7 . .. 7.6 8 7.6 9 10 11 12 . . 13 14 15 16 17 18 19 20 21 22 2.00 2.42 2.50 2.50 2.58 2.75 2.58 2.50 2.50 3.9 6.6 7.2 7.2 7.9 9.4 7.9 7.2 7.-2 24 27 28 29 30 31 Mean discharge 7.17 0.121 0.04 9.4 3.9 A 8.43 0.142 0.16 13.5 6.9 A 7.99 0.161 Run-off (depth in inches on drainage 0,05 Maximum 8.7 7.6 Accuracy A Discharge measurements of Canyon Creeh beloiu Squaw Gulch, 1912. Date. Gage height. Dis- charge. Date. Gage height. Dis- charge. June 5 Feet. 2.66 2.10 Sec.-ft. 46.7 7.83 Aug. 8 Feet. 2.98 2.54 Scc.-ft. 82.0 Jiily 5 23 34.7 116 SUKFACE WATER SUPPLY OF YUKON-TAN" AN A REGION, ALASKA. Daily gage height, in feet, and discharge, in second-feet, of Canyon Creek below Squaw Gulch for 1912. [Drainage area, 56.5 square miles.] . June. July. August. September. Day. Gage height Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. 1 2.45 2.45 2.40 2.50 2.45 2.55 2.85 2.85 3.10 3.20 3.15 2.85 2.55 2.70 2.55 2.45 2.60 4.00 3.15 3.40 3.15 2.80 2.60 2.70 2.55 2.85 2.80 27 2 27 3 23 4 31 5 2.65 46 2.10 7.8 27 6 3.75 3.50 3.10 2.85 2.85 4.40 3.60 3.45 3.15 2.90 2.85 2.70 2.70 2.85 2.70 2.60 2.60 2.60 2.50 2.45 2.40 2.60 2.60 2.55 2.45 2.55 195 155 99 67 67 300 171 148 106 73 67 51 51 67 51 41 41 41 31 27 23 41 41 36 27 36 36 7 67 8 67 9 99 10 113 11 106 12 67 13 36 14 51 15 36 16 27 17 41 18 235 19 106 20 141 21 106 22 61 23 41 24 51 25 36 26 67 27 61 28 30 31 79.0 1.40 1.35 300 23 C 66.1 Second-feet per square mile 1.17 Run-oS (depth in iuches on drainage area) 1.17 235 Minimum 23 Accuracy C SQTJAW GULCH AT CLAIM "NO. 1 ABOVE." This station was established at claim ''No. 1 above/' on Squaw Gulch, one-half mile below Baby Creek, IJ miles above the mouth, and about 18 miles from Steel Creek post office, on July 3, 1910, and was maintained at the same point during three seasons. The ratings are fairly well defined for low stages. FOETYMILE EIVER DRAINAGE BASIN. 117 Discharge measurements of Squaw Gulch at claim "No. 1 above," 1910-1912. Date. Gage height. Dis- charge. Date. Gage height. Dis- charge. July 3 1910. Feet. 1.79 1.67 2.19 2.67 1.52 1.75 Sec.-ft. 2.5 1.5 11.0 50.8 a. 30 2.97 June 4 . . 1912. Feet. 1.29 .55 1.29 1.20 Sec.-ft. 24.1 Aue. 2 July 5 1.61 17 Aug. 8 22.9 1911. 23.. 10.4 June 6 . . July 23 Sept. 1 a Discharge estimated. Daily gage height, in feet, and discharge, in second-feet, of Squaw Gulch at claim "No. 1 above'' for 1910-1912. [Drainage area, 24.4 square miles. Observer, Frank Montgomery.] July. August. September. Day. July. August. September. Day. -1-5 to 'S © c3 ,d o ft 'S ,d 0 o 3.20 3.28 3.29 3.27 3.30 3.35 3.32 3.30 3.29 3.28 23 25 26 26 25 26 28 27 26 26 25 September. O 3. 75 3.65 3.60 3.55 29.8 0.642 0.74 64 52 46 42 32.6 0.703 0.63 66 24 C LAWSON CREEK AT MOUTH. This station was established June 30, 1912, on Lawson Creek, about 300 feet above the mouth of Munson Creek. The rating curve is not very well defined. The discharge during the period covered by the records was probably greater than normal. Discharge measurements of Lawson Creek at mouth in 1912. Date. Gage height. June 30. July 2. Feet. 3.15 3.08 Dis- charge. Sec.-ft. 18.7 14.7 Date. Aug. 25. Sept. 3. Gage height. Feet. 3.03 3.04 Dis- charge. Sec.-ft. 14.2 13.9 174 SUEFACE WATER SUPPLY OF YUKON'-TANAN'A EEGION, ALASKA. Daily gage height, in feet, and discharge, in second-feet, of Lavomn Creeh at mouth for 1912. [Drainage area, 21.6 square miles. Observer, C. N. Banks.] July. August. September. Day. to I 6 03 O ft ft o3 o 03 O ft 1 3.13 3.08 3.03 3.02 3.00 2.98 3.00 3.00 3.00 3.37 3.20 3.08 3.03 3.12 3.08 3.05 3.02 3.06 3.02 3.02 17.2 15.4 14.1 13.8 13.3 12.9 13.3 13.3 13.3 35 20 15.4 14.1 16.8 15.4 14.6 13.8 14.9 13.8 13.8 *3.'6i' 3.00 2.98 3.30 3.15 3.11 3.10 3.30 's.'io' 3.12 3.10 3.05 15 14 14 13.6 13.3 12.9 27 18.1 16.3 15.9 27 25 23 21 19 17 15.9 16.8 15.9 14.6 3.04 3.02 3.02 3.03 3.02 3.03 3.01 3.01 3.03 3.02 3.01 3.02 3.01 3.00 3.04 3.08 3.10 3.11 3.11 3.30 14.3 13.8 13.8 14.1 13.8 14.1 13.6 13.6 14.1 13.8 13.6 13.8 13.6 13.3 14.3 15.4 15.9 16.3 16.3 27 2 3 4 5.......... 6 7 8 9 10.... 11 12 13 14 15.. 16... 17 18 19 20 Day. Mean dis- charge. . Second-feet per square mile Run-off (depth in inches on d r ainage area) Maximum. . Minimum . . Accuracy... July. O 3.04 3.02 3.02 3.00 2.98 3.01 3.15 3.15 14.3 13.8 13.8 13.3 12.9 13.6 18.1 18.1 18 17 16 15.6 0.722 0.83 35 12.9 C August. r-Cj 3.03 3.10 3.12 3.03 3.06 3.05 3.02 3.02 3.04 3.03 14.1 15.9 16.8 15 14.1 14.9 14.6 13.8 13.8 14.3 14.1 16.7 0.773 0.89 27 12.9 B September. O 3.28 3.20 3.20 3.20 26 20 20 20 16.0 0.741 0.66 27 13.3 B BUCKLEY BAR CREEK AT MOUTH. Buckley Bar Creek enters Birch. Creek from the north at Buckley Bar, about a mile above Sheep Creek. This station was established June 2, 1911. The gage was located on the left bank about one-eighth mile from Birch Creek and just above the intake to a small ditch carry- ing water to Buckley Bar. The rating curve is fairly well defined for all stages. Discharge measurements of Buckley Bar Creek at mouth, 1911 . Date. Gage height. Dis- charge. Date. Gage height. Dis- charge. June 2 . . 1911. Feet. 2.10 2.14 1.14 1.11 1.37 Sec.-ft. 25 29 .45 .36 1.5 May 28.. 1912. Feet. 1.81 2.54 2.20 1.47 Sec.-ft. 4.4 2 29 33 July 27 30 17.8 30 July 14 .63 Aug. 19 Note.— Zero of 1912 gage was 0.30 foot below that of 1911. BIRCH CEEEK DEAINAGE BASIN. 175 Daily gage height, in feet, and discharge, in second-feet, of Buckley Bar Creek at mouth for 1911-12. [Drainage area, 10.6 square miles. Observer, Chas. H. Rogers.] May. June. July. August. September. Day. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. 1911. 1 1.28 1.30 1.81 1.71 1.62 1.53 1.50 1.46 1.38 1.31 1.30 1.31 1.28 1.26 1.25 1.22 1.22 1.21 1.20 1.20 1.20 1.20 1.19 1.18 1.16 1.16 1.14 1.12 1.11 1.11 1.11 1.0 1.1 9.4 6.5 4.6 3.2 2.8 2.4 1.7 1.2 1.1 1.2 1.0 .92 .88 .74 .74 .70 .65 .65 .65 .65 .62 .59 .52 .52 .46 .39 .36 .36 .36 1.10 ■"i.'io' 1.09 1.09 1.09 'i'io' 1.09 1.10 1.10 1.10 1.10 1.10 1.26 1.42 "'i.'46" 1.37 1.30 ""i.'24" 1.23 1.22 1.21 '*'i.'22' 1.24 1.23 0.34 .34 .34 .32 .32 .32 .33 .34 .32 .34 .34 .34 .34 .34 .92 2.0 1.9 1.8 1.6 1.4 1.1 .90 .83 .78 .76 .74 .70 .72 .74 .83 .78 1.23 ""i."22' 1.22 1.22 ""i,'23' 1.24 1.27 1.31 1.32 1.32 1.32 1.30 1.30 ""i."28' 0.78 2 2.10 1.94 1.89 1.86 1.87 1.77 1.70 1.66 1.60 1.56 1.52 1.56 1.56 1.54 1.50 1.70 1.90 1.76 1.66 1.52 1.49 1.44 1.41 1.37 1.35 1.35 1.34 1.30 1.30 25 14.5 12.2 11.1 11.4 8.2 6.2 5.4 4.2 3.6 3.1 3.6 3.6 3.4 2.8 6.2 12.5 7.9 5.4 3.1 2.7 2.2 1.9 1.6 1.4 1.4 1.4 1.1 1.1 .76 3 .74 4 .74 5 .74 6 .74 7 .76 8 .78 9 .80 10 .82 11 .83 12 .96 13 1.2 14 1.2 15 1.2 16 1.2 17 1.1 18. 1.1 19 1.0 20 1.0 21 23 24 25 26 28 29 30 31 5.61 0.529 0.59 25 1.1 B 1.55 0.146 0.17 9.4 0.36 A 0.780 0.074 0.09 2.0 0.32 A 0.922 Second-feet per 0.087 Run-off (depth in area) 0.10 1.2 Minimum 0.74 Accuracy A 176 SURFACE WATER SUPPLY OF YUKON'-TAN-AKA REGION, ALASKA. Daily gage height, in feet, and discharge, in second-feet, of Buckley Bar Creel at mouth for -?9ii-i^.— Continued. May. June. July. August. September. Day. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. 1912. 1 2.30 2.62 2.30 22 39 22 13.5 5.0 3.6 4.0 4.6 5.2 3.4 1.5 3.4 4; 2 4.0 6.0 12.0 17.0 12.0 22 12.0 4.4 7.8 12.0 30 41 26 7.8 5.5 3.9 3.6 1.70 "'i.'62' 1.59 1.52 1.51 ""i.'48' 1.50 ""i.'47' 1.48 1.46 1.47 '"i.'ss" 1.56 '"'i.'55" ""i.'53' "'iVbh' 1.48 ""i.'47' 2.6 2.2 1.7 1.4 1.2 .90 .82 .70 .67 .75 .72 .69 .66 .63 .67 .59 .63 1.0 1.4 1.2 1.2 1.1 1.1 1.0 .98 .86 .75 .67 .65 .63 .62 ""'i."46' "'i.'45' "'i.'96' 1.95 1.87 2.11 2.51 '"'i.'84' 1.82 1.79 1.75 '"'i."72* "'i.'io' 1.85 1.91 1.85 1.72 "'l.ih' 0.61 .60 .59 .57 .55 1.0 8.0 7.8 5.7 9.0 13.1 33 16.0 10.0 7.0 5.0 5.0 4.6 4.0 3.4 3.2 2.9 2.8 2.6 3.9 5.2 6.6 5.2 2.9 2.8 2.6 1.90 1.96 "'"i."93" 1.88 1.84 "'i.'93' 'i.'84" ""'i.'92' ""i."94' ""2.' 68" 6.3 8.0 7.8 7.5 7.2 5 9 2.. 3 4 5 1.84 1.76 6 7 5 n 8 5 n 9 1.85 1.75 1.60 1.75 L80 7.2 10 11 6 12 5 5 13 1 5 14 6 15 6 Q 16 7 17 7 18 7 5 19 16 20 25 21 1.70 1.65 1.88 1.76 2.6 2.0 5.9 3.6 2.8 2.0 3.2 4.4 34 17.0 9.9 1.81 1.95 2.08 2.46 2.65 2.38 1.95 1.86 1.78 1.76 34 22 43 23 24 25 26 1.65 27 28 1.81 2.54 2.20 2.02 29 30 31 Mean discharge square mile 7.95 0.750 0.31 34 2.0 B 1.19 0.112 0.12 41 1.5 B .990 0.093 0.11 2.6 0.59 B 5.68 0.536 0.62 33 0.55 B 10.7 1.01 Run-ofl (depth in inches on drainage area) .83 Maximum .43 .50 Accuracy B SHEEP CREEK AT MOUTH. A gage was installed June 2, 1911, on the right bank of Sheep Creek, about 100 feet from Birch Creek. Only occasional gage readings were obtained, but from the dis- charges at Birch Creek above Sheep Creek and of Buckley Bar Creek at mouth, where daily records were obtained, the discharge on days of missing gage heights could be estimated with considerable accuracy. Discharge measurements of Sheep Creek at mouth in 1911-12. Date. 1911 June 2 July 27 30 Aug. 19 Gage Dis- height. charge. Feet. Sec.-ft. 3.50 101 2.45 3.6 2.42 3.6 3.20 50 Date. 1912 May 28 29. July 14.'.".".!!." Gage height. Feet. 3.03 3.97 2.76 Dis- charge. Sec.-ft. 25 154 8.9 BIRCH CREEK DRAINAGE BASIN, 177 Daily gage height, in feet, and discharge, in second-feet, of Sheep Creek at mouth for 1911-12 . [Drainage area 46.7 square miles. Observers: G. L. Dalby, 1911; Charles Rogers and B. Lokkan, 1912.] June. July. August. September. Day. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. 1911. 1 2.60 8.2 2 3.50 101 3 2.38 2.5 4 5 2.35 2.0 6 3.10 38 7 8 3.90 3.38 208 78 9 2.58 7.6 10 11 3.22 53 2.64 9.8 12 13 2,60 2.65 3.05 8.2 10.2 34 14 2.71 12.7 15 2.60 8.2 16 2.70 12.2 17 18 4.05 255 3.20 50 2.91 23 20 2.50 .5.1 21 23 2.78 16.0 3.21 51 25 26 27 2.45 4.0 2.76 15.1 28 2.95 26 2.65 10.2 30 2.42 3.3 2.70 12.2 Note.— Rating curve is fairly well defined below 150 second-feet. 42913°— WSP 342—15 12 178 SURFACE WATER SUPPLY OF YUKOK-TAI^AIS-A REGION, ALASKA. Daily gage height^ in feet, and discharge, in second-feet, of Sheep Creek at mouth for 1911-12— Continued. May. June. July. August. Day. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. 1912. 1 2 2.72 6.8 3 4 3.40 67 6 2.76 8.3 6 7 4.12 179 8 3.05 26 9 10 11 12 13 14 15 16 3.52 84 17 18 3.12 3.10 33 19 3.90 i42 31 20 3.52 84 2.80 9.8 21 3.85 134 22 3.40 67 23 24 2.80 9.8 25 2.95 18.6 26 - 2.74 7.5 27 28 3.03 4.20 3.79 25 193 124 29 3.35 60 30 31 3.75 118 3.00 22 Note. — Rating curve fairly well defined for all stages. BACHELOR CREEK BELOW COSTA FORK. This station was established on Bachelor Creek about 1 J miles below Costa Fork on June 8, 1909, but daily gage readings were not com- menced until June 25, 1909. The rating curve for 1909 is fairly well defined for all stages. The discharges for 1910 are only approximate because of insufficient measurements and shifting channel. Below Costa Fork the creek has a grade of about 70 feet per mile. In 1909 about a mile of ditch with the intake a short distance below Costa Fork was partly constructed along the left limit of the creek, in accordance with a plan to mine the Bachelor Creek gravels by hydraulic elevators. The scheme has apparently been abandoned, for nothing has been done since 1909. BIKCH CEEEK DRAINAGE BASIN. 179 Discharge measurements of Bachelor Creek below Costa Fork, 1909-10. Date. 1909 June 8 25 26 Aug. 15 16 Gage height. Feet. 1.82 1.65 1.61 1.10 1.08 Dis- charge. Sec.-ft. 53 32 28 10 8.5 Date. 1910. July 11 12 30 Gage height. Feet. 1.49 1.44 1.48 Dis- charge. Sec.-ft. 6.6 5.8 8.5 Note.— Zero of 1910 gage was 0.45 foot below that of 1909. Daily gage height, in feet, and discharge, in secondfeet, of Bachelor Creek below Costa Fork for 1909-10. [Drainage area, 11.4 square miles.] 1909 1910 Day. Jiuae. July. August. September. July. Ga^e height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. 1 1.44 1.41 1.42 1.42 1.44 1.41 1.38 1..32 1..32 1.38 1.35 1.26 1.42 1.41 1.42 1.38 1.31 1.64 1.50 1.32 1.24 1.20 1.61 1.25 1.25 1.20 1.16 1.15 1.14 1.15 1.15 19.2 17.8 18.2 IS. 2 19.2 17.8 16.6 14.5 14.5 16.6 15.6 12.8 18.2 17.8 18.2 16.6 14.2 30 22 14.5 12.2 11.2 29 12.5 12.5 11.2 10.4 10.2 10.0 10.2 10.2 1.15 1.12 1.10 1.10 1.10 1.08 1.08 1.11 1.16 1.20 1.18 • 1.15 1.10 1.10 1.10 1.10 1.08 1.05 1.05 1.05 1.05 1.05 1.02 1.02 1.02 1.02 1.02 1.02 1.00 1.00 1.00 10.2 9.6 9.2 9.2 9.2 8.9 8.9 9.4 10.4 11.2 10.8 10.2 9.2 9.2 9.2 9.2 8.9 8.4 8.4 8.4 8.4 8.4 7.9 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.98 .98 .98 .98 .98 .98 7.6 7.6 7.6 7.6 7.6 7.6 7.6 7.6 7.6 7.3 7.3 7.3 7.3 7.3 7.3 2 3 4 5 6 7 8 9 10 11 1.49 1.48 1.44 1.40 1.39 1.38 1.42 1.60 1.49 1.46 1.45 6.6 12 6.4 13 5.9 14 5.3 15 5.2 16 5.0 17 5.6 18 8.5 19 8.2 20 7.8 21 7.6 22 23 24 7.9 7.9 7.9 7.9 7.9 7.6 7.6 7.6 26 1.65 1.60 1.52 1.48 1.46 1.45 31 28 23 21 20 19.6 1.48 1.45 1.44 1.42 1.41 1.48 8.1 26 7.6 27 7.4 28 7.1 29 7.0 30 8.5 31 Mean discharge.. 24 2.11 0.47 31 19.6 B 15.9 1.39 1.60 30 10.0 B 8.9 0.78 0.90 11.2 7.6 B 7.5 0.66 0.37 7.6 7.3 B 6.9 Second -feet per SQuare mile 0.61 Run-off (depth in inches on drainage area) 0.39 Maximum 8.5 5.0 Accuracy C 180 SUBFACE WATER SUPPLY OF YUKON-TANANA REGION, ALASKA. MISCELLANEOUS MEASUREMENTS. The following miscellaneous discharge measurements were made in the Birch Creek drainage basin, 1908 to 1912: Miscellaneous measurements in Birch Creeh drainage basin for 1908-1912. Date. Stream. Tributary to — Locality. Dis- charge. Drain- age area. Dis- charge per square mile. July Sept. June Aug. July July June July Aug. Sept. July July Sept. Jime Aug. June Sept. June 10 Sept. 6 Do. July 27 July 5 Jime 24 Aug. 14 July 18 July 18 Aug. 18 June 24 Aug. 14 July 18 Aug. 18 Aug. 14 July 28 July 18 July 18 Aug. 18 July 9 Jime 24 Aug. 14 July 28 July 18 Jime 6 July 18 Aug. 18 July 10 July 11 Aug. 14 July 11 June Aug. July Aug. Aug. June Aug. July Sept. July July July 1908 1908 1909 1909 1910 1911 1912 1912 1912 1908 1908 1908 1908 1909 1909 1912 1908 1909 1908 1910 1912 1909 1909 1911 1912 1912 1909 1909 1912 1912 1909 1910 1911 1912 1912 1908 1909 1909 1910 1911 1912 1912 1912 1908 1908 1909 1908 1909 1909 1911 1911 1911 1912 1912 1908 1908 1910 1910 1908 Ptarmigan Creek do do do do do do do , do , Eagle Creek do , do do do do do Miller Fork of Eagle Creek. do Miller Fork ditch do Golddust Creek do do do .....do do do Fish Creek , do do do Butte Creek do do do do Bear Creek , do do , do do..... do do do Twelvemile Creek do do do Birch Creek do do do do do do do do do do do do do do do Eagle Creek Mouth. do. do. do. do. do. do. do. do. Below Mastodon Fork. Below Cripple Creek. . Mouth do do do... do Above ditch intake.... -do. Birch Creek do ..do.... ..do.... .-do.... ..do.... .-do.... ..do.... ..do.... ..do.... .-do-.-. .-do—. ..do.-, .-do— . ..do— . ..do.... .-do- — ..do- — .-do-.. .-do— .-do.— .-do-.. .-do- — .-do- — .-do— . ..do.— .-do.... .do.... do Intake Outlet.. 4 1 miles above mouth. . 3 miles above mouth. . , Mouth -do. .do. .do. -do. .do. .do. .do. .do. .do. -do. .do. .do. .do. .do. .do. .do. .do. .do. .do. .do. .do. .do. .do. .do. .do. .do. .do. .do. .do. .do. .do- .do. North Fork Twelve- mile Creek. do do do do do do do do do do do do Twelve mile Creek. do 5 miles above mouth . . do do Between North and South forks. do....: do. do. do. do. do. do. Mouth . do. do. do. do. Sec.-ft. 26.2 24.7 34 27 15.0 4.6 29 5.0 15.6 04. 2 10.5 15.4 24.7 19.4 22 17.0 2.1 9.9 2.8 1.4 8.6 5.0 15.9 15.7 3.6 6.9 9.3 6.6 7.1 .52 3.1 5.6 2.2 -do- 3.5 5.5 6.2 20.3 21 12.9 6.7 4.3 14.0 2.5 7.2 6.3 6.0 4.6 15.6 17.6 19.5 5.9 &4.3 4.8 14.3 6.8 38 73 18.9 14.6 24.4 23.9 Sq. mi. 19 19 19 19 19 19 19 19 19 8.4 12.4 15.5 15.5 15.5 15.5 15.5 2.6 2.6 Sec.-ft. 1.38 1.30 1.79 1.42 .79 .24 1.53 .26 .82 9.5 10.0 13.6 13.6 13.6 13.6 13.6 6.0 6.0 6.0 6.0 9.2 9.2 9.2 9.2 9.2 11.6 12.4 12.4 12.4 12.4 12.4 12.4 12.4 10.4 10.4 10.4 23 23 23 23 23 23 23 23 44. 44. 44. 44. 22. 22.9 85 99 59 25 42 09 81 3.81 .90 .50 1.17 1.15 .38 .51 .68 1.10 1.18 .087 .52 .61 .24 .38 .60 .67 1.75 1.69 1.04 .54 .35 1.13 .20 .58 .61 .58 .44 .68 .77 .85 .26 .19 .21 .62 .30 .85 1.64 .42 .33 1.07 1.04 Sept. 4,1908 o Some water was diverted past the section by the ditch from Miller and Mastodon forks; this measure- ment shows the seepage from the diversion dams and ditches. h These measurements probably indicate about the minimum run-off for the season. BIRCH CEEEK DRAINAGE BASIN. 181 Miscellaneous measurements in Birch Creeh drainage basin for 1908-1912 — Continued. Date. Stream. Tributary to — Locality. Dis- charge. Drain- age area. Dis- charge per square mile. June 24,1909 North Fork Twelve- mile Creek. . .do T-welvemile- Creek. ....do Mouth Sec.-ft. 51 18.5 60 7.4 9.2 5.5 a 2. 6 7.5 23 7.7 13.2 6.5 7.0 3.8 70 62 118 a 24 32 30 3.0 a 4.2 4.9 19.1 52 7.1 15.7 108 96 49 28 17.9 36 o24 a53 a 26 45 115 16.4 7.6 2.1 Sq. mi. 22.9 22.9 22.9 22.9 22.9 22.9 22.9 22.9 22.9 22.9 44.7 33.3 27.7 27.7 106 106 172 172 34.7 34.7 15.4 50.8 17.9 21.6 47.3 6.2 6.3 n.4 U.4 n.4 n.4 11.4 25.1 217 320 99.2 94.7 121 26.4 26.4 4.5 Sec.-ft. 2.23 Aug. 14,1909 do .81 June 9, 1910 .do ...do .. ..do 2.62 July 13,1910 do do do .32 July 28,1910 do do do .40 July 17,1911 do do do .24 Aug. 3,1911 do ....do do .11 Aug. 14,1911 do do do .33 June 8, 1912 do ....do do 1.00 Aug. 17,1912 do ....do ....do .34 July 19,1912 Do Harrington Fork Crooked Creek Acme Creek do Harrington Fork. Birch Creek do Above Crooked Creek. Mouth .30 .20 July 3,1912 Aug. 25,1912 2 miles above mouth. . do .25 do .14 July 3, 1912 Clums Fork do Below Bear Creek do .66 Aug. 25,1912 July 25,1910 do do .58 do do Mouth .69 Aug. 1,1911 do do do .14 July 3,1912 Bear Creek Clmns Fork .do .92 Aug. 25,1912 Jiily 25,1910 do .. ..do .do .87 McLean Creek Birch Creek do .20 July 30,1911 Wolf Creek do 1 m il e above mouth . . . Elevation 2,200 feet.... Above North Fork Below North Fork Elevation 2,600 feet.... Claim "No. 10 above ". Claim "No. 5 above".. do .083 July 8, 1908 July 22,1909 Do Harrison Creek do do do .27 .88 do ..do 1.10 July 8,1908 Aug. 13,1909 North Fork Harrison Creek. do 1.15 do 2.49 June 13,1909 do do 9.47 Do do do 8.42 June 11,1909 do do do 4.30 Jime 22,1909 do do do 2.46 June 23,1909 do ....do do 1.57 July 22,1909 do do Mouth 1.43 July 27,1911 South Fork Birch Creek .do Above Big Windy Creek. Below Big Windy Creek. Mouth .11 Do do .17 Do Big Windy Creek Preacher Creek South Fork of Birch Creek. do .26 July 29,1910 Above Bachelor Creek. Below Bachelor Creek. Mouth .48 Aug. 15,1909 do do .95 Do Bachelor Creek do Costa Fork Preacher Creek. do Bachelor Creek. .62 July 29,1910 July 11,1910 do do .29 .47 a These measurements probably indicate about the minimum run-off for the season. CROOKED CREEK DRAINAGE BASIN. DESCRIPTION. Crooked Creek, which is formed by the junction of Mammoth and Porcupine creeks, meanders through a rather broad valley for about 30 miles and discharges its waters into Birch Creek about 10 miles above Fourteenmile House. Not far below Central House the valley loses its identity in the fiats of Birch Creek. Mastodon and Independence creeks unite to form Mammoth Creek, which receives Miller Creek from the west about 2 miles below the junction. The total length of that portion of the stream called Mammoth Creek is less than 4 miles. 182 SURFACE WATER SUPPLY OF YUKOIT-TANANA REGION, ALASKA. Mastodon Creek (see PL VI, A) is the most important gold-producing stream in the Circle district. Its water supply is very small but is exceedingly important for local use. Three small hydraulic plants have been installed on the creek. They have sufficient water to operate only a small part of the time but can be used to a good advan- tage to strip the ground and prepare it for other methods of recovering the gold. Deadwood and Boulder creeks are tributaries from the south, below and above Central House, respectively. They follow parallel courses about 3 miles apart and are each about 18 miles long. Albert Creek, the principal tributary from the north, drains the southern slope of the Crazy Mountains. Portage Creek rises in the divide between Birch and Crooked creeks, about 10 miles east of Deadwood Creek. It flows northeast for about 8 miles to Medicine Lake. Placer mining in the Circle district is largely confined to the tribu- taries of Crooked Creek. Most of the richer claims are now worked out and the problem of obtaining water for hydraulicking the low- grade ground is particularly difficult. Dredging or other methods requiring relatively small quantities of water to recover the gold may have to be resorted to. The run-off from the area is less than from adjoining areas. The creeks are liable to a very low minimum dis- charge and, owing to the steep barren slopes, are flashy in character. Nearly all the timber in the headwaters has been cut off and much of the basin has been burned over. PORCITPINE CREEK ABOVE DITCH INTAKE. Porcupine Creek rises on the north slope of Porcupine Dome. Its headwater tributaries interlock with those of Loper and Willow creeks at an elevation of 4,000 to 5,000 feet. It flows east for about 14 miles and unites with Mammoth Creek to form Crooked Creek. Its vaUey is extremely asymmetric ; the north side is steep and narrow and uncut by any streams of consequence; the south slope is more gradual and contributes most of the drainage. Considerable spruce grows along the banks of the stream and on the northern slope. On the south the basin is nearly devoid of all tree growth. Bonanza Creek, the largest tributary of Porcupine Creek, enters it about 4 miles above its mouth. Its upper basin is rather steep and barren and causes wide fluctuations in stream flow. Large bodies of ice accumulate in the stream bed during the winter and aid slightly in keeping up the flow early in the summer. The water for the hydraulic plant on Mammoth Creek (see p. 333) is diverted from Porcu- pine and Bonanza creeks at an elevation of about 2,350 feet and is conducted to the left bank of Mammoth Creek by a ditch 10.3 miles long. The lower part of the ditch, below the Bonanza intake, was BIRCH CEEEK DEAINAGE BASIN. 183 constructed in 1908 and 1909 and is 6.5 miles long with a bottom width of 7 feet and a grade of 5 feet per mile. The upper section, between Bonanza and Porcupine creeks, was completed in 1910. Some of the construction methods used were described in a previous report,^ as follows : Much difficulty was experienced in completing this section of the ditch on account of ground ice along the steep slopes near the Porcupine intake. Wherever the ditch line crossed these pockets of nearly clear ice, the ice was kept exposed to the open air and a drain provided to expedite thawing. This process of thawing quickly opened up a good-sized hole in the side of the hill, and when it was possible to provide a good foundation the space below the ditch was filled in with layers of moss and dirt. This ditch was built to a grade of 5.3 feet per mile, with a width of 6.5 feet on the bottom. The usual form of construction, which consists of making the bottom of a ditch level, was not followed in building the upper ditch. The method adopted constitutes digging the side next to the hillside five-tenths deeper than the embankment side. When carrying water, a ditch with this cross section will have its greatest depth next to the hillside, and as the highest velocity of a stream or ditch is usually at the deepest section it is thought that the tendency of the water to cut the embankment will thus be decreased. The thawing of ground ice beneath the bottom of the ditch and seepage through loose rock soil has been a continual source of trouble along the lower ditch. These troubles have been described as follows : ^ The ditch was built along the hillside, and as the ice in the bottom thawed the water followed the hue of thaw until often it finally escaped to the surface below the lower bank. Unless these underground channels were soon discovered and moss was tamped into the openings in the bottom of the ditch, they rapidly wore larger and frequently only a few hours were required before the whole outside bank of the ditch near the break was groundsluiced away. In many places where the bottom of the ditch was impervious the outer bank, which is mostly in fill, settled and shd, and if allowed to fall below the water level the overflowing water did considerable damage if not immediately stopped. Moss sod was generally used for repair work. In repair- ing the large breaks the bottom and sides were built up with soil and then fined with sod. Moss was thoroughly tamped into all holes and crevices in the bottom and then puddled with clay. In repairing the settling bank the sod was cut in rectangular strips and successive layers were placed and tamped as the settling proceeded. In some places this settling and rebuilding continued to such an extent that very Uttle, if any, of the original fill could be seen. In order to determine the water available for diversion a gage was placed in the creek about 100 feet above the intake to the ditch on June 6, 1910. Daily readings were obtained from July 4 to August 18, 1910. A dam which was later constructed caused backwater on the gage and the station was abandoned. 1 Ellsworth, 0. E., and Parker, G. L., Placer mining in the Yukon-Tanana region: U. S. Geol. Survey Bull. 480, pp. 161-162, 1911. 2 Ellsworth, C. E., Placer mining in the Yukon-Tanana region: U. S. Geol. Survey Bull. 442, p. 236, 1910. 184 SURFACE WATER SUPPLY OF YUKON-TAIsrANA REGION, ALASKA. Discharge measurements of Porcupine Creek above ditch intake in 1908-1911. Date. Gage height. Dis- charge. Date. Gage height. Dis- charge. July 6.. 1908. Feet. Sec.-ft. 12.6 25 June 6 1910. Feet. Sec.-ft. 25 1909. July 15.. 22.. 0.36 .51 3.3 10.2 Aug. 12. July 20.. 1911. 2.7 Daily gage height, in feet, and discharge, in second-feet, of Porcupine Creek above ditch intake for 1910. [Drainage area, 17.8 square miles. Observer, Frank Miller.] July. August. Day. July. August. Day. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage heignt. Dis- charge. 1 0.79 .68 .55 .55 .49 .45 .44 .44 .41 .40 .38 .36 .36 .35 .35 .35 .33 .35 23 17.7 11.4 11.4 8.8 7.1 6.7 6.7 5.4 5.0 4.5 4.0 4.0 3.7 3.7 3.7 3.2 3.7 21 0.58 .52 .50 .56 .55 .51 .48 .45 .45 1.48 1.12 12.8 10.1 9.2 11.9 11.4 9.6 8.4 7.1 7.1 62 41 2 22 3 23 4 0.50 9.2 14 11 5.0 5.0 3.7 5.0 4.5 .3.7 3.7 4.0 4.0 2.9 3.0 30 27 17.7 24 5 25 6 26 7 .40 .40 .35 .40 .38 .35 .35 .36 .36 .32 27 8 28 9 29 10 30 31 11 Mean dis- charge... 12 12.3 0.691 0.80 62 2.9 B 13 7.43 14 Second-feet per square mile 15 0.417 16 Run-off (depth in inches on drainage area) . Maximum 17 0.28 18 .92 .85 .68 23 19 Minimum 3.2 20 Accuracy B Note. — Discharges above 15 second-feet are only approximate. PORCUPINE CREEK BELOW DITCH INTAKE. This station was established June 2, 1912. The gage was located about 200 feet below the intake dam. The natural flow of the creek at this point can be obtained by adding the discharge of the Porcupine ditch at the intake. The records are only approximate during me- dium stages, but show fairly accurately the periods when the entire flow was being diverted. Discharge measurements of Porcupine Creek below ditch intake in 1912. Date. Gage height. Dis- charge. Jime 2 Feet. 3.01 1.89 Sec.-ft. 75 Sept. 7 5.0 Note. — Zero discharge at about gage height 1.5. BIRCH GREEK DRAINAGE BASIN. 185 Daily gage height, in feet, and discharge, in second-feet, of Porcupine Creek below ditch intake for 1912. [DraiBage area, 17.8 square miles. Observer, Frank Miller.) June. July. August. September. Day. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. 1 2.50 2.40 2.20 1.92 s 27 22 13.5 5.6 1.85 2.25 2.22 2.12 2.02 1.85 1.78 1.68 1.70 1.70 1.60 1.55 2.50 2.40 2.48 2.32 2.25 4.2 2 3.02 75 55 35 12.8 2.9 1.6 5.1 27 34 71 121 56 34 60 66 15,4 56 214 295 228 40 18.3 3.2 15.4 3 14.3 4 . 2.61 2.18 1.78 1.70 10.7 5 8.0 6 4.2 7 2.9 8 1.4 9 1.6 10 1.6 11 . . .6 12 1.90 2.50 2.60 2.98 3.40 2.85 2.60 2.88 2.85 2.25 2.85 4.15 4.75 4.25 2.68 2.32 1.80 1.50 .3 13 i4 15 16 27 17 22 18 26 19 18.3 20 15.4 21 . . . 23 25 26 27 28 29 30 ; Mean discharge 52.3 2.19 8.70 Note. — ^The discharge rating curve for this station is fairly well defined below 75 second-feet. PORCITPINE CREEK BELOW BONANZA CREEK. This station was established July 4, 1908. The gage was located about 300 feet below the mouth of Bonanza Creek. The channel conditions were fairly stable during periods of medium and low water, but at times of high water radical changes have taken place, and several different rating tables have been used in estimatiag the discharges. The gage datum has remained constant. 186 SURFACE WATER SUPPLY OF YUKON-TANANA REGION, ALASKA. Discharge measurements of Porcupine Creek helovj Bonanza Creeh in 1908-1912. Date. 1908, July 4.. 6.. Sept. 7.. 1909, June 11.. 21.. Aug. 11.. Gage Dis- height. charge. Feet. Sec.-ft. 1.55 25 1.58 26 1.70 39 2.70 246 2.30 64 1.98 32 Date. 1910. May 29.. June 5 . . July 15.. 22.. 1911 June 5 . . July 20.. 20.. Aug. 16.. Gage Dis- height. charge. Feet. Sec.-ft. 1.90 24 2.18 59 1.48 9.7 1.51 13.2 1.98 50 1.29 1.6 1.35 2.8 1.30 1.6 Date. 1912 June 2. July 5 . Aug. 19. Sept. 7. Gage height. Feet. 2.55 .82 .83 1.08 Dis- charge. Sec.-ft. 141 1.0 1.4 10.1 Daily gage height, in feet, and discharge, in secondfeet, of Porcupine Creek below Bonanza Creek for 1908-1912. [Drainage area 39.9 square miles. Observer, Frank Miller.] 1908 a 1909 6 Day. July. August. June. July. August. September. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. 1 1.37 1.37 1.32 1.30 1.29 1.30 1.28 1.32 1.48 1.50 16.1 16.1 14.6 14.0 13.7 14.0 13.5 14.6 21 22 19 18 24 17.5 16.0 13.3 30 44 72 46 33 29 153 109 113 57 33 30 22 16.5 14.2 15.0 12.5 11.6 11.2 10.8 12.5 14.6 24 24 26 1.82 1.82 1.88 1.82 1.80 1.77 1.78 1.86 2.06 2.14 2.00 1.96 1.92 1.91 1.78 1.73 1.70 1.70 1.70 1.70 1.70 1.70 1.68 1.66 1.64 1.62 1.62 1.60 1.60 1.60 1.58 21 21 25 21 20 18.5 19.0 24 38 46 33 30 27 27 19.0 16.5 15.0 15.0 15.0 15.0 15.0 15.0 14.2 13.3 12.5 11.6 11.6 10.8 10.8 10.8 10.0 1.67 1.66 1.64 1.64 1.62 1.61 1.60 1.60 1.60 1.60 1.58 1.60 1.60 1.60 1.60 13.7 2 13.3 3 12.5 4 1.55 1.53 1.79 2.26 2.10 1.95 1.85 1.90 1.72 1.64 1.72 1.76 1.72 1.68 1.61 1.52 1.49 1.44 1.40 1.42 1.50 1.51 1.48 1.46 1.44 1.44 1.42 1.40 25 24 46 121 90 67 54 60 39 32 39 43 39 35 29 23 22 19.0 17.0 18.0 22 23 21 20 19.0 19.0 18.0 17.0 1.75 1.72 1.66 1.96 2.12 2.36 2.14 2.00 1.94 2.74 2.56 2.58 2.24 2.00 1.95 1.84 1.73 1.68 1.70 1.64 1.62 1.61 1.60 1.64 1.69 1.86 1.86 1.90 12.5 5 11.6 6 11.2 7 10.8 8 10.8 9 10.8 10 10.8 11 2.70 2.90 2.70 2.68 2.78 2.60 2.60 2.50 2.40 2.35 2.32 246 335 246 240 164 117 117 96 78 71 67 66 64 58 54 51 47 43 39 35 10.0 12 10.8 13 10.8 14 10.8 15 10.8 16 17 18 19 20 21 22 23 2.30 2.25 2.22 2.19 24 25 26 27... 28 29 30 31 Mean dis- charge . . 35.8 0.897 0.93 121 17.0 B 16.0 0.401 0.15 22 13.5 B 112 34.6 19.4 11.4 Second-feet per square mile... Run-off (depth in inches on drainage area) Maximum Minimum Accuracy C B A A o No water diverted above gage. h The discharges for 1909 do not include water diverted above gage and as no daily records of such diver- sion are available the natural discharge for 1909 can not be determined. BIKCH CEEEK DRAINAGE BASIN. 187 Daily gage height, in feet, and discharge, in second-feet, of Porcupine Creek below Bonanza Creek for 1908-1912— Continued. May. June. July. August. September. Day. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. 1910. a 1 2.32 2.23 2.32 2.22 2.14 2.10 1.99 1.92 2.13 2.43 2.26 2.17 2.06 1.95 1.95 2.03 1.97 1.86 1.92 2.05 2.56 2.51 2.22 1.88 1.81 1.78 1.89 1.94 2.14 1.98 77 65 77 64 54 50 39 34 53 96 69 58 46 36 36 43 38 30 34 45 125 112 64 31 27 25 31 35 54 38 1.76 1.66 1.58 1.50 1.77 1.72 1.60 1.52 1.49 1.46 1.42 1.41 1.40 1.38 1.48 1.44 1.46 2.10 1.82 1.66 1.59 1.52 1.50 1.58 1.57 1.50 1.46 1.56 1.68 2.54 2.12 24 18.2 14.8 12.0 24 21 15.5 12.7 11.6 10.6 9.2 8.8 8.5 8.0 11.3 9.9 10.6 50 27 18.2 15.2 12.7 12.0 14.8 14.4 12.0 10.6 14.1 19.1 120 52 1.87 1.73 1.64 1.58 1.48 1.48 1.55 1.51 1.48 1.46 1.46 1.42 1.42 1.40 1.38 1.40 1.40 1.41 1.40 1.43 '"'i."42' 1.42 1.42 1.45 1.47 1.46 1.44 1.43 1.42 30 22 17.3 14.8 11.3 11.3 13.8 12.4 11.3 10.6 10.6 9.2 9.2 8.5 8.0 8.5 8.5 8.8 8.5 9.6 9.5 9.4 9.2 9.2 9.2 10.2 11.0 10.6 9.9 9.6 9.2 1.42 1.42 1.41 1.40 1.48 1.54 1.54 1.52 1.51 1.50 1.50 1.50 1.48 1.50 2.05 2.06 1.98 1.89 1.81 1.72 9.2 2 9.2 3 8.8 4 8.5 5 11.3 6 13.4 7 13.4 8 12.7 9 12.4 10 12.0 11 12.0 12 12.0 13 11.3 14 . 12.0 15 45 16 46 17 38 18 31 27 20 21 21 23. 25 26 27 28 2.04 2.21 2.44 35 53 85 30 31 57.7 C 52.9 C 20.1 B v.'.'.'.'.'.'. 11.3 A 18.3 Accviracy A 1911.0 2.52 2.38 2.58 2.50 2.44 2.32 2.28 1.98 1.79 1.61 1.66 1.74 1.64 1.55 1.48 1.34 1.41 1.40 1.30 1.34 1.39 1.38 1.36 1.40 1.40 1.40 1.39 1.40 1.35 1.30 1.28 148 118 162 144 131 106 98 50 28 14.7 18.2 24 16.8 11.1 7.7 2.7 4.7 4.3 1.7 2.7 4.0 3.8 3.3 4.3 4.3 4.3 4.0 4.3 3.0 1.7 1.3 1.29 1.28 1.30 1.28 1.28 1.28 1.28 1.27 1.27 1.28 1.26 .26 1.28 1.28 1.30 1.30 1.42 1.64 1.53 1,44 1.30 1.30 1.28 1.28 1.28 1.28 1.28 1.26 1.28 1.28 1.5 1.3 1.7 1.3 1.3 1.3 1.3 1.1 1.1 1.3 .9 .9 1.3 1.3 1.7 1.7 5.1 16.8 10.2 6,0 1.7 1.7 1.3 1.3 1,3 1,3 1,3 .9 1.3 1.3 1.3 1.28 1.28 1.28 1.28 1.28 1.31 1.30 1.30 1.29 1.30 1.31 1.30 1.31 1.48 1.3 2 1.3 3 1.3 4 1.3 2.10 2.38 2.18 2.12 2.08 1.95 1.88 1.90 2.09 2.08 2.28 2.22 2.24 2.22 2.23 2,02 2.00 1.92 1.94 1.88 1.80 1.76 1.82 1.70 1.80 2.02 67 118 81 70 64 46 38 40 66 64 98 88 91 88 89 55 52 42 45 38 29 26 31 21 29 55 1.3 2.0 7 1.7 8 1.7 9 1.5 10 1.7 11 2.0 1.7 13 2,0 14 7.7 15 16 18 20 21 22 24 25 26 27 28 29 30 31 58.9 B 36.5 B 2.38 A 2,04 Accuracy A a To determine the natural discharge for 1910 and 1911 add the discharge of Bonanza ditch at intake. 188 SUKFACE WATER SUPPLY OF YUKON-TANANA REGION, ALASKA. Daily gage height, in feet, and discharge, in second-feet, of Porcupine Creek below Bonanza Creek for 1908-19 U—Qo^Xximed.. June. July. August. September. Day. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. 1912. 1 . . . 0.90 .90 .88 .86 .84 .83 .80 .80 .80 .80 .80 .80 .80 .80 .80 .78 .80 .80 .80 .80 .80 .80 .80 .80 .80 ""'.'so" 3.0 3.0 2.6 2.1 1.7 1.5 .8 .8 .8 .8 .8 .8 .8 .8 .8 .7 .8 .8 .8 .8 .8 .8 .8 .8 .8 .8 .8 .8 .8 .8 .8 '"6." so" """."so" 1.50 1.40 1.25 '"i'.m .90 """"."ss" "'".'so' ""."so" ""*96" .90 0.8 .8 .8 .8 .8 .8 .8 .8 .8 .8 39 30 19.8 13.4 7.0 3.0 2.4 1.9 1.3 .8 .8 .8 .8 .8 .8 .8 1.9 3.0 3.0 3.0 3.0 '""i."36" 1.40 1.35 1.25 1.18 """"."97" 1.00 '"'"."ss' 1.40 """i."76" """i.'so" 13.0 2 2.55 2.55 2.10 1.48 1.42 1.40 1.37 1.35 1.35 1.32 1.35 1.80 1.85 1.80 2.60 2.20 2.75 2.10 1.68 1.55 2.20 3.4 3.1 2.8 2.2 1.85 1.35 1.00 .92 142 142 67 7.6 5.2 4.4 3.5 2.9 2.9 2.0 2.9 29 34 29 150 83 176 67 19.6 11.2 83 297 320 251 133 81 26 7.0 3.8 23 3 30 4 26 5 19.8 6 . . 15.5 7 12.3 8 9.0 9 5.8 10 7.0 11 5.7 12 4.4 13 3.1 14 1.9 15 16 16 30 17 46 18 61 19 50 20 39 21 22 23 24 25 26 27 28 29 30 31 75.3 D 1.09 A 4.69 B 20.9 Accuracy B a To determine the natural discharge for 1911 add the discharge of the Bonanza ditch at intake. Note. — Channel shifted considerably on Jxme 23 and 24. New rating applied, begtohitig June 24. Old rating only approximate. New rating curve well defined below 15 second-feet. To obtain the natural flow for 1912 add the discharge of Bonanza ditch below junction with Porcupine branch. CROOKED CREEK AT CENTRAL HOUSE. This station was established June 15, 1909. The creek divides a short distance above the gage, which is located in the main channel. This channel carries all the flow at low and medium stages. The relation between gage height and discharge has not remained con- stant. Channel conditions have changed to some extent and the gage datum has varied slightly from year to year. Sufiicient meas- urements, however, have been made, so that each year, with the exception of 1909, the rating curve has been fairly well defined, and it is improbable that any large errors have been introduced. The minimum discharge recorded at this station was 4.5 second- feet and occurred from August 5 to 15, 1911. Beneath the creek bed there is probably considerable thawed gravel, through which most of the low-water flow passes. BIRCH CREEK DRAINAGE BASIN. 189 Discharge measurements of Crooked Creek at Central House in 1908-1912. Date. Gage height. Dis- charge. Date. Gage height. Dis- charge. Date. Gage height. Dis- charge. 1908. June 30 Feet. Sec.-ft. 58 52 86 319 239 143 165 1910. May 30 31 July 17 19 20 1911. May 29 31... July 23 25 Feet. 1.59 1.82 .66 1.50 1.35 1.78 1.58 .32 .25 Sec.-ft. 208 311 30 172 122 306 230 12.5 10.0 1911— Contd. Aug. 17 21 1912. May 26 31 July 7 13 15 Sept. 9 Feet. 0.62 .55 1.25 1.52 .66 .56 .49 1.06 Sec.-ft. 27 July 1 28 Sept. 9 1909. June 15 20 Aug. 9 10 1.82 1.68 1.30 1.45 101 187 21 12.2 9.1 65 Daily gage height, in feet, and discharge, in second-feet, of Crooked Creek at Central House for 1909-1912. [Drainage area, 161 square miles. Observers: H. A. Stade, 1909, 1911-12; "W. H. Bayless, 1910.] Jvme. July. August. September. Day. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. height. Dis- charge. 1909. 1 ^ 1.28 1.15 1.05 1.20 1.20 1.20 1.25 1.42 1.65 1.52 1.40 1.32 2.75 2.20 2.32 1.78 1.45 1.30 1.20 1.05 1.00 .85 .80 .80 .68 .65 .55 .65 1.28 1.18 1.28 138' 122 113 128 128 128 134 162 228 186 158 144 1,170 635 744 294 169 140 128 113 109 97 93 93 84 82 75 82 138 126 138 1.28 1.18 1.20 1.35 1.20 1.08 .98 1.05 1.30 1.42 1.38 1.28 1.22 1.18 1.08 .98 .92 .88 .80 .92 1.02 1.05 .88 .78 .68 .68 .72 .62 .52 .45 .40 138 126 128 149 128 115 107 113 140 162 154 137 130 126 115 107 103 99 93 103 111 113 99 91 84 84 87 79 73 69 66 0.35 .30 .25 .20 .10 .00 63 2 60 3 58 4 55 5 50 6 45 7 8 9 10 11 12 13 14 15 1.80 1.90 1.50 1.95 1.85 1.65 1.50 1.45 1.38 1.62 1.55 1.65 1.58 1.58 1.45 1.32 305 380 180 420 342 228 180 169 154 216 194 228 202 202 169 144 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Mean discharge 232 1.44 0.86 420 144 C 202 1.25 1.44 1,170 75 C 111 0.69 0.80 162 66 C ^^ Second-feet per square mile 0.34 0.08 Rvm-ofl (depth in inches on drainage area) Maximum Minimum 45 Accuracy c 190 SUEFACE WATER SUPPLY OF YUKON-TANANA REGION, ALASKA. Daily gage height, in feet, and discharge, in second-feet, of Crooked Creeh at Central House for 1909-1912— Continued. May. June. July. August. Day. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. 1910. 1 1.40 1.50 1.63 1.65 1.35 1.40 1.30 1.25 1.20 1.80 1.70 1.60 1.50 1.40 1.30 1.25 1.30 1.25 1.15 1.10 1.30 1.90 1.70 1.50 1.30 1.20 1.20 1.50 2.00 2.10 139 173 225 234 126 139 112 102 91 300 255 212 173 139 112 102 112 102 82 74 112 348 255 173 112 91 91 173 397 448 1.90 1.50 1.30 1.10 1.30 1.55 1.30 1.10 1.05 1.00 .95 .90 .85 .80 '""."67" 1.70 1.50 1.35 1.25 1.30 1.35 1.30 1.20 1.10 1.00 .90 .80 .70 1.60 348 173 112 74 112 192 112 74 68 61 56 50 45 40 36 33 30 255 173 126 102 112 126 112 91 74 61 50 40 32 212 1.50 1.20 1.10 1.00 .90 .85 .70 .65 173 2 91 3 74 4 61 5 50 6 45 7 32 8 29 9 10 11 12 13 14 15 1.50 1.50 1.30 1.25 1.20 1.30 1.35 1.40 1.30 1.40 1.60 1.30 1.10 173 173 112 102 91 112 126 139 112 139 212 112 74 50 173 234 300 16 17 18 20 21 :... 23 25 26 27 28 1.50 1.65 1.80 30 143 0.888 0.56 300 50 B 173 1.07 1.19 448 74 B 103 0.640 0.74 348 32 B 69.4 Second-feet per square mile 0.431 area) 0.13 0,173 Minimum 29 Accuracy B BIRCH CEEEK DRAHSTAGE BASIN. 191 Daily gage height, in feet, and discharge, in second-feet, of Crooked Creeh at Central House for 1909-1912— Continued. • June. July. August. September. Day. Gage height. Dis- charge. Gage height. Dis- e. Gage height. Dis- charge. Gage height. Dis- charge. 1911. 1 2.05 1.85 1.75 1.70 1.78 2.20 1.95 1.58 1.75 1.62 1.48 1.45 1.70 1.72 1.80 1.68 1.70 2.05 1.90 1.68 1.55 1.50 1.42 1.42 1.32 1.25 1.25 1.22 1.20 1.18 416 332 292 273 304 481 374 229 292 243 194 184 273 265 281 266 273 416 353 266 218 200 174 174 146 128 128 120 115 111 1.18 1.50 2.68 2.45 2.38 1.95 1.90 1.55 1.42 1.15 .95 .95 .95 .82 .70 .68 .70 .70 .62 .62 .60 .60 .52 .30 .24 .24 .18 .18 .20 .10 .08 Ill 200 695 591 560 374 353 218 174 104 68 .68 68 51 38 36 38 38 32 32 30 30 24 12.2 10.0 10.0 8.1 8.1 8.5 6.5 6.2 0.02 - .02 - .05 - .05 - .05 - .05 - .05 - .05 - .05 - .05 - .05 - .05 - .05 .50 .55 .60 .45 .50 .50 .50 .40 .35 .30 .30 .30 .25 .30 .25 .20 5.3 2 5.0 3 5.0 4 4.8 5 4.5 6 4.5 7 4.5 8 4.5 9 4.5 10 4.5 11 4.5 12 4.5 13 4.5 14 4.5 15 4.5 16 23 17 26 18 30 20 20 23 21 23 23 23 17.0 14.6 25 12.2 26 . 12.2 27 12.2 28 10.4 1.80 1.68 1.65 312 266 254 12.2 30 10.4 8.5 277 1.72 0-19 312 254 A 251 1.56 1.74 481 111 A 129 0.801 0.92 695 6.2 A 11.2 Second-feet per square mile 0.070 area) 0.08 30 Minimum 4.5 Accuracy A 192 SURFACE WATER SUPPLY OF YUKON-TANANA REGION, ALASKA. Daily gage height, in feet, and discharge, in second-feet, of CrooTced Creeh at Central House for 1909-1912— Gontimied. May. June. July. August. September. October. Day. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. 1912. 1 2.40 2.60 2.30 1.80 1.45 1.25 1.18 .98 .95 .95 .80 .85 1.35 1.45 1.40 2.50 1.90 1.55 2.05 1.70 1.40 1.52 2.80 3.20 3.10 2.60 2.05 1.70 1.50 1.15 546 635 503 293 164 106 89 52 48 48 30 36 132 164 147 590 334 198 397 254 147 187 726 916 868 635 397 254 180 82 1.00 .92 .90 .88 .80 .75 .68 .65 .60 .65 .65 .60 .58 .55 .50 .50 .50 .50 .45 .48 .45 .45 .48 .45 .45 .50 .45 .45 .48 .45 .40 55 44 41 39 30 26 19.7 17.8 14.5 17.8 17.8 14.5 13.6 12.2 9.8 9.8 9.8 9.8 8.6 9.3 8.6 8.6 9.3 8.6 8.6 9.8 8.6 8.6 9.3 8.6 7.5 0.40 .45 .45 .45 .45 .45 .55 .95 .90 .95 .98 1.50 1.48 1.28 1.15 1.05 1.00 .90 .88 .90 .85 .82 .80 .80 .80 .80 .95 .98 .95 .90 .90 7.5 8.6 8.6 8.6 8.6 8.6 12.2 48 41 48 52 180 173 113 82 64 55 41 39 41 36 32 30 30 30 30 48 52 48 41 41 1.00 1.22 1.30 1.35 1.25 1.28 1.25 1.18 1.10 1.05 1.08 1.10 1.10 1.05 1.05 1.10 1.45 1.80 1.60 1.58 1.62 1.65 1.48 1.30 1.25 1.18 1.10 1.10 1.09 1.09 55 98 118 132 106 113 106 89 72 64 69 72 72 64 64 72 164 293 216 209 224 235 173 118 106 89 72 72 70 70 1.08 1.05 1.00 .95 .90 .90 .88 .90 .90 .85 .80 .80 .90 .90 1.00 1.00 1.00 1.00 69 2 64 3 55 4 48 5 41 6 41 7 39 8 41 9 0.80 .75 .82 .98 1.15 1.52 1.30 1.42 1.60 1.58 1.60 1.42 1.30 1.38 1.85 1.52 1.42 1.32 1.25 1.42 1.80 1.85 1.55 30 26 32 52 82 187 118 154 216 209 216 154 118 141 214 187 154 124 106 154 293 214 198 41 10 36 11 30 12 30 13 41 14 41 15 55 16 55 17 55 18 55 19 20 21 22 23 24 25 26 27 28 29 30 31 ■ Mean dis- charge. . Second-feet per square mile . . Eun-off (depth in inches on drainage area) Maximum 147 0.913 0.78 293 26 A 305 1.89 2.11 916 30 B 16.6 0.103 1.19 55 7.5 A 47.0 0.292 0.34 180 7.5 A 116 0.720 0.80 293 55 A 46.5 0.289 0.19 69 Minimum 30 Accuracy A BONANZA CREEK ABOVE DITCH INTAKE. This station was established July 4, 1908. Serious changes in the channel took place during the period covered by the records. The data are subject to large errors and should only be used with extreme care. Discharge measurements of Bonanza Creek above ditch intake in 1908-9. Date. Gage height. Dis- charge. Date. Gage height. Dis- charge. July 4.. 1908. Feet. 1.00 1.02 .92 Sec.-ft. 12.4 13.0 12.3 June 12.. 21.. Aug. 11.. 1909. Feet. 1.95 .50 .20 Sec.-ft. 82 6.. 26 Sept. 7.. 16 BIRCH CREEK DRAINAGE BASIN. 193 Daily gage height, in feet, and discharge, in second-feet, of Bonanza Creek above ditch intake for 1908-1910. [Drainage area, 7.9 square miles. Observer, Frank MUler.] 1908 1909 Day. July. August. June. July. August. September. Gage height. Dis- charge. Gage 1 Dis- height. charge. Gage height. Dis- charge. Gage Dis- height. charge. Gage height. Dis- charge. Gage height. Dis- charge. 1 . . 8 8 8 8 8 0.21 .20 .48 .28 .20 .15 .18 .18 .30 .32 .32 .32 .78 .29 .62 .32 .24 .24 .22 .22 .21 .21 .21 .20 .18 .16 .17 .19 .22 .22 .22 16.0 15.7 25 17.9 15.7 14.5 15.2 15.2 18.5 19.2 19.2 19.2 49 18.2 34 19.2 16.8 16.8 16.3 16.3 16.0 16.0 16.0 15.7 15.2 14.7 15.0 15.5 16.3 16.3 16.3 0.24 .28 .28 .18 .28 .28 .20 .25 .28 .28 .19 .27 .24 .22 .20 .18 .15 .13 .13 .11 .10 .10 .08 .05 .17 .16 .13 .12 .11 .10 .08 16.8 17.9 17.9 15.2 17.9 17.9 15.7 17.1 17.9 17.9 15.5 17.7 16.8 16.3 15.7 15.2 14.5 14.0 14.0 13.5 13.3 13.3 12.9 12.4 15.0 14.8 14.0 13.8 13.5 13.3 12.9 0.04 - .02 - .04 - .04 - .05 - .06 - .08 - .08 - .09 - .09 - .10 - .10 - .10 - .10 12 2 2 11.1 3 10.8 4 1.00 12 12 13 37 35 27 19 18 16 14 13 12 11 11 10 10 10 9 9 9 10 10 10 9 9 9 9 9 0.72 .71 10.8 5 10 6 6 1.02 1.65 1.60 10.4 7 10.1 8 10.1 9 10 10 .. 1.20 10 11 9 8 12 0.95 .70 .68 .60 .60 82 40 38 32 32 32 30 28 27 26 26 26 24 22 20 20 20 20 19.2 9 8 13 .98 .94 .92 9.8 14 9.8 15 16 17 18 19 20 .81 .80 .78 21 .50 22 23 .50 24 .83 1 25 26 .81 .79 .80 ... 27 28 29 30 .32 31 Mean dis- charge. . 12.3 1.56 180 37 9 D 8 1.01 0.19 8 8 D 30 3.80 2.68 82 19.2 B 18.4 2.33 2.69 49 14.5 B 15.3 1.94 2.24 17.9 12.4 B 10.4 Second-feet per square mile . . 1.32 Run-off (depth in inches on drainage area) Maximum .68 12.2 Minimum 9.8 Acctiracy B Day. June. July. Day. June. July. 1910. 1 . 38 32 36 30 29 23 20 20 24 42 35 30 21 16 15 19 16 12 14 19 19 15 10 9 32 25 14 12 13 10 9 8 8 7 5 5 5 30 18 13 1910— Continued. 2) 28 30 27 24 15 18 18 20 35 30 11 2 22 10 3 23 11 4 24 16 5 25 12 6 26 9 7 27 8 8 28 8 9 29 8 10 30 27 31 30 1] Mean discharge 12 24.5 3.10 3.46 D 13.5 13 Second-feet per square mile. . . Run-off (depth in inches on drainage area) 1.71 14 J5 1.97 Accuracy D 16 17 18 19 20 Note. — These discharges were obtained by indirect methods and may be considerably in error. 42913°— WSP 342—15 13 194 STJKFACE WATER SUPPLY OF YUKON-TANAITA EEGION, ALASKA. BONANZA CREEK BELOW DITCH INTAKE. A gage was installed on Bonanza Creek June 5, 1911, just below the ditch intake, to take the place of the one above the intake at which records had been kept during the three previous years. In order to obtain the natural flow of the creek at this point the discharge of Bonanza ditch at intake should be added. Discharge measurements of Bonanza Creeh below ditch intake, 1911-12. Date. Gage height. Dis- charge. Date. Gage height. Dis- charge. June 5 . . 19n. Feet. 3.35 2.65 Sec.-ft. 18.6 0.30 .Tune 2. . 1912. Feet. 5.10 4.48 4.48 Sec.-ft. 44 July 20 July 5 .28 Sept. 7 a. 50 a Estimated. Daily gage height, in feet, and discharge, in .second-feet, of Bonanza Creek below ditch intake for 1911-12. [Observer, Frank Miller.] June. July. August. September. Day. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. 1911. 1 3.06 3.00 3.44 3.22 2.95 2.70 2.70 2.68 2.68 2.68 2.68 2.68 2.66 2.64 2.64 2.64 2.64 2.64 2.64 2.64 2.64 2.64 2.64 2.64 2.65 2.65 2.65 2.65 2.65 2.65 2.65 6.7 5.0 25 12.4 4.0 .7 .7 .5 .5 .5 .5 .5 .4 .3 .3 .3 .3 .3 .3 .3 .3 .3 .3 .3 .3 .3 .3 .3 .3 .3 .3 2.65 2.65 2.65 2.65 2.65 2.65 2.65 2.65 2.65 2.65 2.65 2.65 2.65 2.65 2.65 2.66 2.66 2.66 2.66 2.65 2.65 2.65 2.65 2.65 2.65 2.65 2.65 2.65 2.65 2.65 2.64 0.3 .3 .3 .3 •3 .3 .3 .3 .3 .3 .3 .3 .3 .3 .3 .4 .3 .3 .4 .3 .3 .3 .3 .3 .3 .3 .3 .3 .3 .3 .3 2.64 2.64 2.64 2.64 2.64 2.64 2.65 2.65 2.65 2.65 2.65 2.65 2.65 0.3 2 .3 3 .3 4 .3 5 3.35 3.22 3.12 3.03 3.08 2.88 2.74 2.88 2.98 3.00 3.12 3.00 3.16 2.97 2.96 2.76 2.90 2.90 2.74 2.71 2.71 2.71 2.70 2.70 2.70 2.70 19.0 12.4 8.5 5.8 7.2 2.7 1.1 2.7 4.6 5.0 8.5 5.0 10.0 4.4 4.2 1.2 3.0 .7 1.1 .8 .8 .8 .7 .7 .7 .7 .3 6 .3 7 .3 8 .3 9... .3 10 .3 11 .3 12 .3 13 .3 14 15 16 17 18 19 20 21 22 23 24 25 26 ... 27 28 29 30 31 Mean discharge 4.32 B 2.03 B .30 B .30 Accuracy B BIRCH CREEK DRAINAGE BASIN. 195 Daily gage height, in feet, and discharge, in second-feet, of Bonanza Creek below ditch intake for 1911-12 — Continued, Jmie. July. August, September. Day. Gage height. Dis- charge, Gage height. Dis- charge. Gage height. Dis- charge, Gage height. Dis- charge, 1912. 1 : 4.49 4.49 4.48 4.48 4.48 4.48 4.48 4.48 4.48 4.48 4.48 4.48 4.48 4.48 4.48 4.48 4.48 4.48 4.48 4.48 4.47 4.47 4.47 4.47 4.47 4.47 4.47 4.47 4.47 4.47 4.47 0.4 .4 .3 .3 ,3 .3 .3 .3 .3 ,3 .3 .3 .3 .3 .3 .3 .3 ,3 .3 .3 .3 .3 .3 .3 .3 .3 ,3 .3 .3 .3 .3 4.47 4.47 4.47 4.47 4.47 4.47 4.48 4.48 4.48 4.48 4.64 4.51 4.50 4.52 4.49 4.48 4.48 4.48 4.48 4.48 4.48 4.48 4.48 4.48 4.48 4.48 4.49 4.48 4.49 4.49 4.48 0.3 .3 .3 .3 .3 .3 .3 .3 ,3 .3 2.4 .6 ,5 .7 .4 ,3 ,3 .3 .3 .3 .3 4.48 4.49 4.49 4.49 4.49 4.49 4.48 4.48 4.48 4.48 4.48 4.48 4.48 4.48 4.48 4.48 4.50 4.70 4.60 4.64 4.90 0.3 2 5.20 5.10 4.46 4.22 4.21 4,20 4.20 4.21 4.20 4.20 4.22 4.28 4.38 4.82 5.11 4.27 4.24 4.90 4.32 4.22 4.72 5.70 5.40 5.38 5.15 4.92 4.92 4.60 4.49 51 44 5.3 ,6 .5 .4 .4 .5 ,4 .4 .6 1.3 2.9 25 45 1.2 .8 30 1.9 .6 19 90 46 44 26 12 12 1.6 .4 .4 3 .4 4 .4 5 .4 6 ,4 7 ,3 8 ,3 9 ,3 10 ,3 11 ,3 12 ,3 13 .3 14 ,3 15 ,3 16 .3 17 .5 18 3.7 1.6 20 2.4 21 11 22 23 .3 ,3 ,3 .3 .4 ,4 .4 .4 .3 24 25 26 27 28 29 30 31 16.0 D .31 D .41 D 1.17 Accuracy D Note, — New rating used after June 22, 1912, Discharges only approximate. Seepage through apd beneath the diversion dam was about 0.3 second-foot. INDEPENDENCE CREEK AT CLAIM "NO. 9 ABOVE." This station was established June 6, 1911. The channel was fairly permanent, but sufficient measurements were not made to give a well-defined discharge curve. It was necessary to abandon the sta- tion in 1912 because an indeterminate amount of water was being diverted above the gage for sluicing. Discharge measurements of Independence Creek at claim No. 9 above, 1911-12. Date. 1911. June 6 July 19 Aug, 16 Gage Dis- height. charge, Feet. Sec.-ft. 2.42 41 1.33 2.0 1.36 3.7 Date, June 4. July 6. 1912. Gage height. Feet. 2.46 Dis- charge. Sec.-ft. 22 1,4 196 SUKFACE WATER SUPPLY OF YUKON-TAITANA EEGION, ALASKA. Daily gage height, in feet, and discharge, in second-feet, of Independence Creek at claim ''No. 9 above'' for 1911. [Drainage afea^ 8.6 square miles. Observer, Jack Hendricks.] June. July. Aug ust. September. Day. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. 1 2.58 3.50 2.62 3.54 2.75 2.29 1.83 1.67 1.54 1.42 1.38 1.46 1.38 1.38 1.33 1.33 1.33 1.33 1.33 1.33 1.33 1.29 1.29 1.29 1.29 1.25 1.25 1.25 1.21 1.21 1.21 54 164 58 170 71 32 11.8 7.8 5.3 3.6 3.1 4.1 3.1 3.1 2.6 2.6 2.6 2.6 2.6 2.6 2.6 2.2 2.2 2.2 2.2 1.9 1.9 1.9 1.6 1.6 1.6 1.21 1.21 1.21 1.17 1.17 1.17 1.17 1.17 1.17 1.25 1.25 1.25 1.25 1.29 1.46 1.38 1.38 1.33 1.33 1.29 1.29 1.29 1.29 1.25 1.25 1.25 1.25 1.33 1.33 1.33 1.38 1.6 1.6 1.6 1.3 1.3 1.3 1.3 1.3 1.3 1.9 1.9 1.9 1.9 2.2 4.1 3.1 3.1 2.6 2.6 2.2 2.2 2.2 2.2 1.9 1.9 1.9 1.9 2.6 2.6 2.6 3.1 1.42 1.46 1.38 1.33 1.33 1.29 1.25 1.21 1.17 1.29 1.42 3.6 2 4.1 3 3.1 4 2.6 5 2.6 6 2.38 2.50 2.46 2.33 2.21 2.08 2.42 2.33 2.50 2.67 2.83 3.33 3.17 2.75 2.42 2.33 2.12 2.17 2.21 2.08 1.92 1.79 1.62 2.54 2.25 39 48 45 35 28 21 42 35 48 63 79 140 119 71 42 35 23 26 28 21 14.7 10.6 6.7 51 30 2.2 7 1.9 8 1.6 9 1.3 10 2.2 11 3.6 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 ■ 30 31 , Mean discharge 44.0 5.12 4.43 140 6.7 C 20.3 2.36 2.72 170 1.6 B 2.10 0.244 0.28 4.1 1.3 B 2.62 Second-feet per square mile 0.305 Run-off (depth in inches on drainage area) 0.12 Maximum 4.1 Minimum 1.3 Accuracy B Note. — Above 50 second-feet these records are only approximate. MAMMOTH CREEK AT MILLER HOUSE. This station was established July 2, 1908. The gage was nailed to a log retaining wall on the left bank of the stream just below the bridge opposite the Miller House. The datum of the gage remained constant. During high water the channel shifted considerably and several rating curves were used, all of which were, however, fairly well defined. Since on or about June 19, 1909, a ditch has diverted water from the creek past the gage. As it was not possible to obtain accurate records of the amount diverted the total flow of the stream can be only approximately determined since that date. BIRCH CREEK DRAINAGE BASIN. 197 Discharge measurements of Mammoth Creek at Miller House in 1908-1910. Date. Gage height. Dis- charge. Date. Gage height. Dis- charge. July 2.. 1908. Feet. 0.85 .70 1.00 .90 .85 4.05 4.20 Sec.-ft. 34 21 48 35 31 200 253 1909- June 15 . . . -Continued. Feet. 3.85 3.60 3.08 3.20 3.32 3.19 3.30 Sec.-ft. 120 6 20 70 7 Aug. 12 15.8 Sept. 6 May 29... 1910. 7 1909. 17.1 June 5 27 June 10 . . July 14 16.4 11 23 27 Daily gage height, in feet, and discharge, in secondfeet, of Mammoth Creek at Miller House for 1908-1910. [Drainage area, 37.1 square miles. Observer, J. F. Kelly.] 1908 1909 a Day. September. October. May. June. July. August. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. 1 0.50 .50 .50 .50 .50 .50 .50 .50 .50 .40 .40 .40 .40 14.4 14.4 14.4 14.4 14.4 14.4 14.4 14.4 14.4 13.0 13.0 13.0 13.0 2.15 2.20 2.40 2.80 2.75 2.40 2.20 2.25 4.55 4.00 4.30 4.20 4.25 4.10 3.90 3.75 4.35 4.05 3.60 3.55 3.50 3.50 3.45 3.50 3.45 3.60 3.55 3.55 3.40 3.40 358 377 451 604 584 451 377 396 414 176 294 252 273 212 .142 102 318 194 70 62 53 53 46 53 46 70 62 62 40 40 3.40 3.30 3.00 3.00 3.00 3.00 3.40 3.40 2.40 3.30 3.30 3.35 4.25 4.00 3.85 3.55 3.35 3.30 3.20 3.20 3.10 3.00 3.00 3.00 3.00 3.00 3.00 3.15 3.50 3.40 3.30 40 30 12.0 12.0 12.0 12.0 40 40 40 30 30 35 273 176 128 62 35 30 22 22 16.0 12.0 12.0 12.0 12.0 12.0 12.0 19.0 53 40 30 3.30 3.30 3.20 3.30 3.30 3.25 3.30 3.40 3.45 3.50 3.50 3.25 3.00 2.90 2.90 2.90 2.90 2.82 2.80 2.95 2.90 2.80 2.80 2.80 2.80 2.80 2.80 2.80 2.80 2.80 2.80 30 2 30 3 22 4 30 5 30 6 26 7 30 8 0.90 .80 .90 .85 .70 .75 .70 .75 .70 .75 .70 .90 .85 .80 .70 .60 .60 .55 .50 .50 36 27 36 31 21 23 21 23 21 23 21 36 31 27 21 16.7 16.7 15.4 14.4 14.4 14.9 15.4 14.4 40 9 0.80 .90 .80 .90 .85 .80 1.10 1.40 1.65 1.80 1.40 1.10 1.05 1.00 1.25 1.65 r.75 1.75 1.55 1.55 1.70 2.00 2.00 28 37 28 37 32 28 62 122 190 237 122 62 55 48 88 190 221 221 161 161 205 305 305 46 10 53 11 53 12 26 13 12.0 14 9.0 15 9.0 16 9.0 17 9.0 18 6.6 19 6.0 20 10.5 21 9.0 22 6.0 23 6.0 24 6.0 25 6.0 26 6.0 27 6.0 28 6.0 29 .55 .50 6.0 30 6.0 31 6.0 Mean dis- charge . . Second-feet per square mile. . Run-off (depth in inches on drainage area) Maximum 22.6 0.609 0.52 36 14.4 B 14.0 0.377 0.18 14.4 13.0 B 128 3.45 2.95 305 28 C Minimum 221 C 42.4 B 17.0 Accuracy B a From June 19 to Aug. 17 about 20 second-feet was diverted above gage and should be added to the above discbarges for that period in order to obtain the natural flow of the stream. 198 SURFACE WATER SUPPLY OF YUKON-TAI^ANA REGION, ALASKA. Daily gage height, in feet, and discharge, in second-feet, of Mammoth CreeTc at Miller House for 1908-1910— Qoniim\Qdi. May. June. July. Day. May. June. July. Day. 1 1 03 O o .a ft bX) C3 <6 o .a ® ft o .a i A O •a ft bo CO s 1910. 1 3.50 3.60 3.45 3.35 3.35 3.30 3.20 3.20 3.30 3.45 3.30 3.28 3.22 3.15 3.20 3.32 3.30 3.22 3.25 3.22 47 61 41 30 30 25 17.5 17.5 25 41 25 24 19.0 14.8 17.5 27 25 19.0 21 19.0 3.50 3.30 3.25 3.35 3.75 3.55 3.38 .3.30 3.20 3.20 3.20 3.20 3.20 3.25 3.20 3.15 3.22 3.80 3.40 3.30 47 25 21 30 90 54 33 25 17.5 17.5 17.5 17.5 17.5 21 17.5 14.8 19.0 102 35 25 1910— Con. 21 3.30 3.20 3.55 3.65 3.50 3.25 3.25 3.15 3.40 3.50 3.60 25 175 54 70 47 21 21 14.8 35 47 61 3.60 3.50 3.40 3.38 3.30 3.32 3.45 3.50 3.85 3.50 61 47 35 33 25 27 41 47 115 47 3.30 3.30 3.30 3.10 3.30 3.25 3.20 3.18 3.15 3.20 3.32 25 2 22 25 3 23 25 4 24 35 5 25 25 6 26 21 7 27 17.5 8 28 . 16.4 9 29 14.8 10 30 17.5 31 27 11 Mean dis- charge. . 12 35.2 B 34.1 B 13 28.9 14 Accuracy . . . B 15 3.10 3.15 3.35 3.50 3.50 3.40 12.0 14.8 30 47 47 35 16 17 18 19 20 Note. — From May 26 to July 31 the discharge of Mammoth Creek diversion ditch should be added to the above discharge to obtain the natural flow of the creek. MAMMOTH CREEK DIVERSION DITCH. Mammoth Creek ditch diverts water from Mammoth Creek just above the mouth of Miller Creek. When mining was being done on the creek below the Miller House this ditch was used to carry past the mine all water except what was needed for sluicing. A gage was installed on the ditch at the intake on May 26, 1910, in order to determine the amount diverted, so that the total flow of Mammoth Creek might be computed. The records are rather incom- plete and subject to considerable error because of the unstable con- ditions of the ditch near the gage. Discharge measurements of Mammoth Creeh diversion ditch at intake in 1910. Date. Dis- charge. May 29. June 5 . Sec.-ft. 33 34 Note.— Zero discharge would be at about gage height 1.20. BIRCH CREEK DRAINAGE BASIN. 199 Daily gage height, in feet, and discharge, in second-feet, of Mammoth Creek diversion ditch at intake for 1910. [Observer, J. F. Kelly.] May. June. July. Day. May. June. July. Day. 1 o .a o .S3 'S « a -a 1 1 o3 o ® 1 .a ft to 'S to o .S3 1 2.33 2.31 2.29 2.25 2.23 2.21 2.17 2.19 2.17 2.17 2.19 2.17 2.17 2.27 2.31 2.25 2.33 2.35 2.33 2.27 29 28 26 24 23 22 20 21 20 20 21 20 20 25 28. 24 29 31 29 25 2.27 2.25 2.25 2.25 2.25 2.25 2.67 2.50 2.58 2.37 2.50 2.58 2.42 2.62 2.37 2.42 25 24 24 24 24 24 63 44 53 33 44 53 37 57 33 37 21 2.29 2.29 2.25 2.29 2.19 2.23 2.67 2.75 2.50 2.33 2.29 26 26 24 26 21 23 63 74 44 29 26 2 22 3 23 4 24 5 25 6 26 7 27 8 28 2.54 2.44 2.37 48 39 33 9 29 10 30 31 11 Mean dis- charge . . 12 28.0 .930 1.07 74 20 A 13 37.4 14 Second-feet per square mile 15 1.24 16 Run-off (depth in iaches on d r ainage area) 17 18 .. 19 20 0.74 Maximum . . 63 Minimum . . 24 Accuracy. A MISCELLANEOUS MEASUREMENTS. The following miscellaneous discharge measurements were made in Chena River drainage basin in 1912: Miscellaneous measurements in Chena River drainage basin in 1912. Date. Stream. Tributary to — Locality, Dis- charge. Drain- age area. Dis- charge per square mile. July 19 July 22 22 North Fork of Chena River. Frozenfoot Creek do Chena River West Fork of Chena River. do Below Boulder Creek.. Elevation 1,500 feet.... 2 miles above mouth . . Above Olympia Creek. Mouth Sec.-ft. 24 7.9 14 32 22 Sq. mi. 49.6 21 40.8 106 23.6 Sec.-ft. 0.48 .38 .34 22 22 West Fork of Chena River. Olympia Creek Chena River West Fork of Chena River. .30 .93 LITTLE CHENA RIVER DRAINAGE BASIN. DESCRIPTION. The southern slope of the divide between the Chatanika and Chena drainage basins, from the headwaters of Smith and Flat creeks to Pedro Dome, a distance of about 25 miles, is drained by Little Chena ^52 SURFACE WATER StJPPLY OF YUKOI^-TANANA REGIOK, ALASKA. River and its tributaries, Sorrels and Fish creeks. The drainage basin is irregular in shape and is crossed by a network of small, ramifpng streams with precipitous slopes in their upper courses. The upper portion of the main stream is also steep, having a fall of 100 to 150 feet to the mile, but this slope decreases rather abruptly to about 18 feet to the mile in the vicinity of Sorrels and Fish creeks. Above Fish Creek the Little Chena flows through a rather broad, asymmetric valley, but below that stream it takes the center of a deep, rather narrow channel for about 8 miles, to Anaconda Creek, an important tributary which enters from the left. B^elow this point the valley gradually widens again until the stream reaches the lowlands tributary to Chena River, with which it unites 3 or 4 miles above the confluence of Chena Slough. Through this slough the Chena dis- charges its waters into the Tanana near the town of Chena. The slough affords a passageway for the Tanana steamers from its mouth to Fairbanks, 12 miles above, except in times of low water, when the cargoes are transferred at Chena to the Tanana Valley Railroad. In the low-water period the stream occupies a channel 30 to 75 feet wide, crossing from side to side of a broad, gravelly bed ranging in width from 100 to 300 feet. The channel is defined by steep, alluvial banks that form the approach to the heavily timbered bottom lands which prevail in the river valley above the confluence of Fish Creek. At high-water stages the river completely fills its broad bed, over- flowing the banks and seeking numerous smaller channels that sur- round heavily wooded islands. Solo, Bear, Fairbanks, and Miller creeks are the principal tribu- taries, named in downstream order, of Fish Creek. All of them enter from the left. Elliott Creek rises opposite Kokomo Creek, flows southeast for about 6 miles, and enters Sorrels Creek about 2 miles above the Little Chena. The greater part of the drainage basin is well covered with timber, that in the uplands and on the slopes and smaller divides consisting of spruce, birch, and poplar, suitable only for fuel and cabin building. In the lower valleys and creek bottom lands the prevailing growth is spruce, much of which is suitable for miUing purposes. The area is everywhere covered with the common moss, but here and there limestones, mica schist, and gravel outcrop on the slopes. In the creek vaUeys the mossy covering is usually underlain with frozen muck and glacial ice. LITTLE CHENA RIVER ABOVE SORRELS CREEK. This station was estabhshed July 22, 1907, about 2 miles above Sorrels Creek and about one-half mile below Bonanza Creek. Records of gage heights were kept during part of the summers of 1907 and 1908. On July 3, 1910, a gage was installed on the creek near the CHENA EIVEK DRAINAGE BASIN. 253 location of the original gage but not at the same section. The rating curves for the two gages are, therefore, not comparable. The drainage areas are essentially the same. Gage heights for 1907 and 1908 were obtained in cooperation with Messrs. Joslin, Wobber, and others. Discharge measurements of Little Chena River above Sorrels Creek in 1907, 1908, and 1910. Date. Hydrographer. j^^||\_ Dis- charge. Date. Hydrographer. Gage height. Dis- charge. 1907. July 22 24 C. C. Covert Feet. 0.60 .56 1.10 1.05 .73 1.65 .46 .46 Sec.-ft. 44 40 113 103 57 249 32 34 1910. July 3 10 17 24 Aug. 1 8 20 22 24 G. L. Parker Feet. 1.70 1.68 1.65 2.40 1.85 1.69 2.48 2.13 2.04 Sec.-ft. 30 Covert and "White do do C. C. Covert T. J. Shaw 24 Aug. 4 5 20 do do do 19.7 163 50 1908. Covert and White C. C. Covert Parker and Shaw T. J. Shaw 24 194 Mav 29 July 21 31 do Parker and Shaw 100 77 Geo. Neuner, jr Daily gage height, in feet, and discharge, in second-feet, of Little Chena River above Sorrels Creel for 1907, 1908, and 1910. [Drainage area, 79 square miles. Observers: Sherman White, 1907-8; T. J. Shaw, 1910.] July. August. September. 1 Day. July. August. September. Day. O C3 -d s .d .d ® o .S3 CD ® o 2 03 o o .52 +.3 ® .d o ft <» gf C3 rd o CO s 1907. 1 0.70 1.30 1.10 1.10 1.10 1.00 1.05 1.10 1.20 1.10 1.00 .90 1.00 .80 .90 .80 53 157 113 113 113 95 104 113 134 113 95 80 95 66 80 66 66 60 60 53 53 53 53 53 73 1.00 .90 .90 .80 .90 .95 .95 1.00 'i."66' 95 80 80 66 80 88 88 95 95 95 ■ 1907— Con. 26 0.90 .80 .70 .60 .60 .60 80 66 53 42 42 42 1.00 .90 .90 i.oo* 1.00 95 80 80 88 95 95 2 27 3 28 4.. 29 5 30 31 a Mean dis- charge.. 7 49.3 0.625 0.23 80 42 A 85.4 1.08 1.24 157 53 A 8 85.2 9 Second-feet per square mile 10 1.09 11 Run-off (depth in inches on drainage area) .... 12 13 14 15 0.40 Maximum. . 95 16.. . Minimum . . 66 17. . Accuracy . . . A 18 19 20 .70 .70 .70 .70 .70 21 22. .. 0.60 42 42 42 42 23 24 .60 .60 25 254 SURFACE WATER SUPPLY OF YUKON-TANANA REGION, ALASKA. Daily gage height, in feet, and discharge, in second-feet, of Little Chena River above Sorrels Creek for 1907, 1908, and i9i6>— Continued. Day. May. June. July. August. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. 1908. 1 210 197 185 160 185 223 185 172 160 148 160 172 172 197 197 160 136 148 113 32 2 32 3 1 1.40 32 4 1 29 5 29 6 1.55 1 29 7 0.41 .50 29 8 1 35 9 35 10 1.25 1 32 11 .40 28 12 1 30 13 i 30 14 j .45 32 15 1.45 1 35 16 38 17 : 1.20 42 18 46 19 1.10 .70 52 20 2.20 405 374 374 346 318 290 263 236 210 236 250 250 58 21 0.46 33 33 33 33 33 33 33 33 33 33 33 '""."96' .80 .65 65 22 79 23 65 24 ... 58 25 52 26 46 27 28 29 1.60 30 31 .46 Mean discharge 296 3.75 1.67 405 210 B 173 2.19 1.55 223 113 A 33.0 0.418 0.17 33 33 A 41.1 Second-feet per square mile 0.520 Run-off (depth in inches on drainage area) 0.49 Maximum 79 Mjaimum 28 Accuracy Note.— Discharges on days of missing gage heights were estimated by comparison with discharges at other stations in the Little Chena basin. July. August. Day. July. August. Day. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. 1910. 1... 27 27 27 27 27 27 26 25 25 25 24 24 25 24 23 22 22 22 23 22 1.85 1.78 '"iVn 1.73 1.71 1.70 1.69 1.68 1.68 L67 1.67 1.66 1.65 1.65 1.67 1.70 2.93 ""'2.' 49' 47 37 34 32 31 28 27 26 25 25 24 24 23 22 22 24 27 350 272 194 1910— Con. 21 1.66 1.75 2.09 2.40 2.07 1.90 1.81 1.78 1.74 1.78 1.90 23 33 89 166 85 55 41 37 32 37 55 2.25 2.13 2.04 2.05 2.22 2.15 2.10 2.03 2.00 126 2 22 98 3 1.70 23 80 4 24 82 5 25 100 6 1.70 1.69 1.68 1.68 1.68 1.67 1.67 1.68 1.67 1.66 1.65 1.65 1.65 1.66 1.65 26 118 7 27 102 8 28 91 9 29 78 10 30 72 31 70 11 Mean dis- charge 12 37.0 0.468 0.54 166 22 A 13 74.5 14 Second-feet per square mile 15 0.943 16 Run-off (depth in inches on drainage area) . 17 1.09 18 Maximum 350 19 Minimum 22 20 Accuracy A Note.— Discharge curve well defined below 250 second-feet. che:na eiver deainage basin. 255 LITTLE CHENA RIVER BELOW FISH CREEK. This station was established May 1^ 1908, discontinued August 27, 1908, and reestabHshed July 2, 1910. The gage was located on the right bank of Little Chena River about 250 feet below the mouth of Fish Creek. Measurements were made from a car and cable at high water and by wading at low and medium water. The difference in elevation between the 1908 and 1910 gages is not known, so the records are not directly comparable. The discharge rating curves for each year are fairly well defined. Gage heights for 1908 were obtained ia cooperation with Messrs. Joslui, Wobber, and others. Discharge measurements of Little Chena River below Fish Creek in 1908, 1910-11. Date. Hydrographer. Gage height. Dis- charge. Date. Hydrographer. Gage height. Dis- charge. 1908. Apr. 28 May 2 3 4 Covert and "White do do do do Feet. (a) 6 3.75 4.00 4.00 4.08 1.60 1.50 1.50 1.58 1.80 Sec.-ft. 126 916 887 960 1,030 83 74 75 88 110 1910. May 22 July 4 Aug. 7 14 23 1911. Aug. 6 Ellsworth and Parker. . Parker and Shaw do T. J. Shaw Feet. 2.96 .99 .84 .74 1.54 .71 Sec.-ft. 473 58 44 36 5 Parker and Shaw C.E.Ellsworth 141 Julv 20 21 30 Aug. 3 23 Covert and Ellsworth. . C.E.Ellsworth Geo, Neimer, jr do C. C. Covert 32 a Measurement made before gage was installed, river partly filled with ice. b Some ice running. 256 SUEFACE WATER SUPPLY OP YUKON-TANANA EEGION, ALASKA. Daily gage height, in feet, and discharge, in second-feet, of Little Chena River below Fish Creel for 1908 and 1910. [Drainage area, 228 square miles. Observers, Sherman White and T. J. Shaw, 1910.] May. June. July. August. Day. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. 1908. 1 ^ 3.65 3.70 4.00 4.00 4.05 4.15 3.90 3.71 3.68 3.70 714 746 960 960 998 1,075 885 753 732 746 732 714 732 746 940 1,668 1,510 1,265 1,265 1,320 1,265 870 620 632 465 324 265 489 443 443 512 3.35 2.95 2.65 2.48 3.48 3.55 3.00 2.80 2.48 2.31 2.40 2.60 2.55 2.68 2.98 2.58 2.50 2.70 2.45 2.40 537 367 274 231 608 651 384 318 230 192 212 260 248 282 378 256 235 288 224 212 1.48 1.56 1.58 1.54 1.49 1.44 1.45 1.50 1.50 1.49 1.45 1.40 1,40 1.46 1.49 1.52 1.62 1.60 1.65 1.70 1.82 1.90 1.75 1.72 1.70 1.64 1.65 68 2 78 3 80 4 74 5 68 6 62 7 64 8 70 9 70 10 68 11 64 12 3.65 3.68 3.70 3.98 4.85 4.68 4.38 4.38 4.44 4.38 3.88 3.50 3.52 3.20 2.82 2.62 3.25 3.15 3.15 3.30 59 13 59 14 65 15 68 16 72 17 84 18 82 19 88 20 1.60 1.50 82 70 70 70 70 70 70 70 70 70 70 64 95 111 22 122 101 24 98 25 95 26 86 27 88 28 29 1.50 1.50 1.45 30 31 832 3.65 4.21 1,668 265 C 319 1.40 1.04 651 192 B 70.5 0.309 0.14 82 64 A 79.2 Second-feet per square mile 0.347 area) ■ 0.35 122 Minimum 59 A July. August. Day. July. August. Day. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. 1910. 1 75 70 65 60 58 56 53 50 47 48 48 48 48 47 44 40 38 38 41 JO 1.16 1.06 .98 .96 .92 .89 .86 .84 .84 .82 .80 .78 .76 .74 .75 .78 .91 1.86 2.92 2.18 80 67 58 56 51 48 45 44 44 42 40 39 38 36 37 39 50 194 460 256 1910— Con. 21 0.84 1.03 1.37 2.06 1.58 1.35 1.20 1.08 .99 1.03 1.24 44 64 111 232 145 108 85 70 59 64 91 1.86 1.68 1.56 1.56 1.74 1.76 1.68 1.58 1.50 1.44 194 2 1.08 1.04 1.00 .98 .'96 .94 .91 .88 .89 .89 .89 .89 .88 .84 .80 .76 .76 .81 .80 22 162 3 23 142 4 24 142 5 25 172 6 26 176 7 27 162 8 28 145 9 29 132 10 30 122 31 110 11 Mean discharge Second-feet per square mile. .♦. . 12 67.3 0.295 0.34 232 38 A 13 109 14 0.478 Run-off (depth in inches on drainage area) . 16 0.55 17 18 Maximum. . .. 460 19 Minimum 36 20 Accuracy A CHENA EIVER DRAINAGE BASIN. 257 SORRELS CREEK ABOVE ELLIOTT CREEK. This station was established July 23, 1907, about one-half mile above the mouth of Elliott Creek. It was discontinued August 26, 1908, and reestablished July 3, 1910. The conditions at the station were favorable for accuracy and the results, particularly the records for 1910, should be excellent. Gage heights for 1907 and 1908 were obtained in cooperation with Messrs. Joslin, Wobber, and others. Discharge measurements of Sorrels Creek above Elliott Creek in 1907 , 1908, and 1910. Date. Hydrographer. Gage height. Dis- charge. Date. Hydrographer. Gage height. Dis- charge. 1907. July 3 Aug. 5 Covert and White do C. C. Covert Feet. 1.00 1.40 1.02 1.75 1.09 1.03 Sec.-ft. 10.3 28 12.0 54 11.3 10.5 1910. July 3 10 17 24 31 Aug. 8 18 20 24 Parker and Shaw T. J. Shaw Feet. 1.33 1.32 1.26 2.03 1.46 1.30 1.75 1.92 1.66 Sec.-ft. 4.9 4.7 20 do do 3.6 Covert and White C.C. Covert 43 1908. May 29 July 21 do Parker and Shaw T. J. Shaw 9.4 4.2 25 31 Geo. Neuner, jr do Parker and Shaw 38 17.4 Daily gage height, in feet, and discharge, in second feet, of Sorrels Creek above Elliott Creek for 1907, 1908, and 1910. [Drainage area, 21 square miles. Observers, Sherman White and T. J. Shaw, 1910.] July. August. September. Day. July. Aug ust. September. Day. 6 Ml 1 o m 1 6 o 2 be 1 (S 03 o A o s A c3 A o m ft A '3 A , . , — ^ ; L i 1 A - J i It" 1 4 r i^ i^Qi,,_ /•■- r^^,^-^ -'^=^..7^ ^... — ;;^ ::::::::::■: '' •• ,7]""' •.. )ND-FEET OF CHAT U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 342 PLATE VIM May June July Auprust September October Nov. 1 10 20 30 1 9 19 29 1 9 19 29 1 8 18 28 1 7 17 27 1 7 17 27 1 ( ' V \ i A. J . - - _ _ . . _ _ 1908 _ _ i, / i y ]l 1910 ,; r r\ il" " '"' ' ' " 1911 \ i .'' [j 1912 /? 1 II ! lit \ 1 1 ^ __ _ _4 ■ 1 1 'i\ 1 ' 1 1 iU' V^...A J ' A I J 1 L ii\ d I \ : W 1 1 M—ii—u\—-xi\A:}.A A^i j\ ni \ ;> ' ii it\ "niuA 1 1 1 ■/: , ~~\ r-;—rT\~A r\ {i,'U.u-Lj., __-l,L 'M« U 1 1 I \ i \ A L 1 )■- rfl \ r -^^[^ V :f| ,i - --^ -. - - -J.. 1- ^ _^ -^ -^^. ^i^ ,. f--\y. _. -A' '■■■' V^ H ^ i\^H> '.V^^ '1 Vn'^i ' ^ f'N -K \ /■- --^-^ ^ ' ". " ";\" ~l T"/""/' "Ttr^ 1"", ~ ' f " \i A-\r -- -: --zx ^ /-----A - 7 --/)■-.. -\ "s --/ ^ -^ / ~--s. -''"■^-v ^> ■^- ^ =.'^''^'^^ N^^3_ 2 J ^ "^ v.. '^^^-'<; , --^ . . '''^f%'^ N'' ^=.=:r-^_'- ■■ ?~-^-ii^^-..^ \ .* ~"-^*'? "" ^--^1:1: t '' '■ '~s-- '-■^_- — . J_ ,...,..--=;?" ■-. .. .~~~ "^''H^ -...-.. _L — ^__y " ^ ~ •"■■■' " ^ -..^ _-■■---_' ■■ ■■■.__ __ -. .. ]^7~.. .].7 HYDROGRAPH SHOWING DAILY DISCHARGE IN SECOND-FEET OF CHATANIKA RIVER BELOW POKER CREEK FROM 1907 TO 1912. TOLOVANA EIVER DEAINAGE BASIN. 287 Daily gage height, in feet, and discharge, in second feet, of Chatanika River helow Poker Creek in 1907-1912— Contmued. May. June. July. August. September. October. T>ay. -1^ .to <£ 63 o .a ft '3 to C3 O 03 -s 5 -1-5 'S .a o .S3 ft '3 d O ® S-l 03 •s s .1 © •g .a p 4J '3 c3 O A -a A ® ■8 5 W) A <» C3 6 -1-5 A 6 1 A CO s 1 0.9 .9 32 32 31 30 29 28 27 26 25 24 24 24 24 24 24 24 23 21 20 19 0.6 ""'.'5' .5 13 13 13 12 12 12 12 12 12 12 12 12 12 11 11 11 11 11 10 10 21 59 52 52 52 41 38 35 32 32 24 0.7 .7 .7 17 17 17 17 17 17 16 14 13 13 13 0.5 10 2 22 1.1 1.1 1.1 1.0 10 3 23 10 4 24 10 5 25 9 6 26 9 7 27 9 8 28 .9 .9 .8 9 9 1.3 1.3 74 74 86 97 109 122 122 109 97 86 74 66 .8 .8 .8 .8 29 10 10 30 12 31 14 11 Mean dis- charge.. 12 1.5 1.6 1.7 1.7 69.7 1.58 1.29 122 •24 A 22.0 0.498 0.57 32 13 A 13 11.2 14 Second-feet per square mile 15 0.253 16 Run-off (depth in inches on d r ainage area) 17 1.5 1.4 1.3 18 19 20 0.29 Maximum . . 13 Minimum . 9 Accuracy B Note. — The discharges on days of missing gage heights were estimated by aid of comparative records and known climatologic conditions and are believed to be very nearly correct. MISCELLANEOUS MEASUREMENTS. The following miscellaneous discharge measurements were made in the Hutlinana Creek drainage basin in 1908 and 1909: Miscellaneous measurements in Hutlinana Creek drainage basin, 1908-9. Date. Stream. Tributary to — Locality. Dis- charge. Drain- age area. Dis- charge per square mile. Aug. 20,1908 Sept. 2,1908 July 7, 1909 26, 1909 Hutlinana Creek do Baker Creek.. . do Below Caribou Creek. . do Sec.-ft. 1.9 3.1 a 11. 9 24 9.1 .93 1.1 2.4 2.8 Sq. mi. 16.1 16.1 23.7 23.7 23.7 3.2 3.3 11.4 18.9 Sec.-ft. 0.12 .19 do do Above Denver Creek. . do .50 do do 1.01 Sept. 5, 1909 do do do .38 Aug. 20,1908 Do Ohio Creek Hutlinana Creek. do J mile above mouth . . . Mouth .29 Elephant Gulch .33 Do Goff Creek do I mile above mouth . . . 1 mile above mouth. . . .21 Do Applegate Creek do.. .15 a Measurement made by Clarence Hamshaw. Note. — The measurements of Hutlinana Creek above Caribou Creek and above Denver Creek were made near proposed diversion points for ditch systems to carry water to the mines on Pioneer Creek. SURFACE WATER SUPPLY OF YUKON-TANANA REGION, ALASKA. 323 PATTERSON CREEK DRAINAGE BASIN. DESCRIPTION. Patterson Creek is formed by the junction of Sullivan and Cache creeks. It is about 30 miles long and follows a general southwesterly course roughly parallel to Tanana River, which it joins about midway between Hot Springs and Fort Gibbon. It drains an area of low relief, the most prominent feature of which, Bean Ridge, on the southeast, furnishes it several small tributaries. Sullivan Creek, the right fork of Patterson Creek, rises on the south slope of Roughtop Mountain, and for about 10 miles flows a little west of south through a wide valley, flanked on either side by long, gentle slopes. Birch and spruce timber suitable for cabins and fuel is abundant in the lower vaUey. Woodchopper Creek drains a relatively low swampy area between Sullivan Creek on the east and American Creek and Fish Lake on the west. SULLIVAN CREEK ABOVE TOFTY DITCH INTAKE. A gage was installed on Sullivan Creek August 4, 1908, just above the intake to the Tofty ditch and about 6 miles above the mouth of the creek. During periods of average flow nearly the entire discharge of the creek is diverted just below the gage and conducted in a ditch along the right limit hillside to Tofty Gulch, where it is used in open- cut sluicing. The ditch is 7,000 feet long, with a bottom width of 4.5 feet and a grade of 6| feet per mile. The 1908 rating curve is rather poorly defined. That of 1909 is weU defined below 40 second-feet. The measuring conditions were good and the channel seemed to be fairly permanent. Some water was diverted from the creek above the gage in the Midnight Sun ditch at a time of ample supply in 1909, and the records therefore show a run-off slightly less than the actual one. Discharge measurements of Sullivan Creek above Tofty ditch intake in 1908-9. Date. Gage height. Dis- charge. Date. Gage height. Dis- charge. Aug. 4 . . 1908. Feet. 0.80 .70 Sec.-ft. 5.7 4.5 May 28.. 29.. July 19.. 1909. Feet. 1.00 .72 .11 .12 Sec.-ft. 31 24 11.6 1.8 20.. 2.2 324 SURFACE WATER SUPPLY OF YUKON-TANANA REGION^ ALASKA. Daily gage height, in feet, and discharge, in second-feet, of Sullivan Creek above Tofty ditch intake for 1908-9. [Drainage area, 15.6 square miles. Observer, Joseph Eglar.] 1908 1909 Day. August. May. June. July. August. September. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. Gage height. Dis- charge. 1 0.70 .70 .65 .90 1.00 1.00 .80 .65 .50 .50 .45 .45 .45 .40 .40 .40 .35 .30 .28 .28 .21 .20 .20 .20 .45 .30 .25 .20 .19 .18 13.8 13.8 12.1 24 31 31 18.5 12.1 7.7 7.7 6.6 6.6 6.6 5.5 5.5 5.5 4.8 4.0 3.8 3.8 2.9 2.8 2.8 2.8 6.6 4.0 3.4 2.8 2.7 2.6 0.15 .12 .15 .15 .12 .11 .10 .30 .25 .20 .25 .20 .20 .30 .50 .30 .21 .20 .20 .75 .75 .75 .50 .70 .50 .55 .65 .45 .32 .40 .25 2.3 2.1 2.3 2.3 2.1 2.0 2.0 4.0 3.4 2.8 3.4 2.8 2.8 4.0 7.7 4.0 2.9 2.8 2.8 16.2 16.2 16.2 7.9 13.8 7.7 9.0 12.1 6.6 4.3 5.5 3.4 0.12 .09 .80 .60 1.70 1.50 .90 1.70 2.10 ""'.'so' .50 .40 .25 .25 .25 '".'io' 2.1 1.9 18.5 10.4 106 82 24 106 158 110 70 40 15 7.7 7.7 5.5 3.4 3.4 3.4 3.2 3.0 2.8 2.6 2.4 2.2 2.0 2.0 2.0 2.0 2.0 2.0 "6.'26" "".'26' 2 8 2 2 8 3 2 8 4..: 0.8 .7 .7 .7 .68 .65 .62 .6 .6 .6 .6 .6 .62 .65 1.5 i:4 1.3 .85 .85 .7 .7 6.0 .4.3 4.3 4.3 4.0 3.6 3.2 3.0 3.0 3.0 3.0 3.0 3.2 3.6 42 33 26 7.2 7.2 4.3 4.3 2 8 5 2 8 6 2 8 7 2 8 8 - 2.8 9 2.8 10 2.8 11 2.8 12 2 8 13 2.8 14 2.8 15 2.8 16 2.8 17 2.8 18 19 20 21 22 23 24 25 26 27 28 0.90 .70 .40 24 13.8 5.5 9.6 29 30 31 Mean dis- charge... 8.34 0.533 0.42 42 3.0 C 13.2 0.846 0.13 24 5.5 B 8.59 0.551 0.61 31 2.6 A 5.72 0.367 0.42 16.2 2.0 A 25.9 1.66 1.91 158 1.9 C 2.80 Second-feet per square mile . . 0.180 Run-off (depth in inches on drainage areaj Maximum 0.11 2.8 Minimum 2.8 Accuracy C MISCELLANEOUS MEASUREMENTS. The following miscellaneous discliarge measurements were made in the Patterson Creek drainage basin in 1908 and 1909: Miscellaneous measurements in Patterson Creeh drainage basin in 1908 and 1909. Date. Stream. Tributary to— Locality. Dis- charge. Drain- age area. Dis- charge per square mile. Aug. 26,1908 July 20,1909 Aug. 4, 1908 July 19,1909 May 28,1909 Aug. 25,1908 Quartz Creek Sullivan Creek . do i mile above mouth. . . Mouth Sec.-ft. 2.8 1.3 3.2 2.5 6.5 4.4 Sq. m. 8.0 11.3 22.7 22.7 Sec.-ft. 0.35 do .12 Cache Creek Patterson Creek do Trail crossing to mouth of Baker Slough. do .14 .... do .11 Midnight Sun ditch . . . Outlet Trail crossing Woodchopper Creek... (a) 19.7 .22 a Reconnaissance map of Rampart quadrangle shows Woodchopper Creek flowing into Fish Lake. According to a statement by a local prospector, it is tributary to Patterson Creek, about 6 miles from Tanana River. SURI^ACE WATER SUPPLY OF YUKON-TAi^-ANA EEGIOK, ALASKA. 325 MINIMUM DISCEQVRGE. The computed minimum discharge for a single day is often subject to errors which make it less reliable than the mean for a longer period, and it is therefore customary in estimates of minimum discharge to select the mean discharge for the minimum week. The following table has been compiled to- show the mean discharge in second-feet, and in second-feet per square mile, for the minimum week, from representative drainage areas. It should be borne in mind that all the records are not directly comparable, because their durations at the different stations are not the same. An analysis of the results shows no relation between the size of the drainage area and the minimum flow; in fact, it indicates that within certain limits each drainage area is a law unto itself. The relatively high minimums of Chena River above Little Chena, Salcha River at the mouth, and Seven tymile River at the falls, indicate conditions in the moun- tains occupying the east-central portion of the Yukon-Tanana region which contribute toward an increased minimum discharge. The nature of these conditions is beyond conclusive determination by the data available. The low minimum of South Fork of Fortymile River at Franklin indicates conditions productive of a very low discharge in the southeastern portion of the region. A considerable proportion of this drainage area is flat and swampy and it exercises an influence on run-off somewhat comparable to lake storage, but this does not explain the low minimum except so far as it may be ascribed to increased evaporation losses. Thus comparison and analysis show that the minimum discharges are probably determined by the diverse characteristics of the drain- age areas and vary widely. The minimum run-off in second-feet per square mile for many of the typical placer streams varies from 0.10 to 0.20, and this represents approximately what maybe expected from the average drainage area. Such a run-off, however, is by no means general, for there are many pronounced exceptions dependent upon special condition. Careful study of the existing data and a comparison of physical conditions will furnish a basis for estimating the minimum discharge of streams other than those upon which records are available. The minimum summer flow for several seasons took place on the majority of the streams in the region in the first part of August, 1911. In each of the other seasons, however, the streams fell nearly as low as in 1911. The durations of low-water periods varied from about one to three weeks and in some seasons occurred two or three times. The variations in discharge from the same area for different years are shown on Plate VIII, on which are platted hydrographs of daily discharge of Chatanika River from 1907 to 1912. 326 SURFACE WATER SUPPLY OP YUKOIT-TAI^ANA REGION^ ALASKA. Mean discharge for minimum week at various stations in Yukon- Tanana region. Station. Duration of record. Week of minimum discharge. Mean discharge for Drainage mmimum area. week. Sec.-ft. So. mi. 157 3,180 516 5,890 45 824 12.0 189 .89 23.1 .61 9.1 210 2,010 .23 12.5 7.0 59.5 .47 24.4 2.1 24.1 1.0 14.8 136 465 17.3 36.7 1.4 17.2 11.7 88 19.5 141 54 600 90 873 218 2, 150 .33 10.6 2.4 39.9 4.5 161 1.2 21.3 14.8 76 6.8 43.2 31 130 4.1 27.7 .60 5.9 1,050 2,170 3.8 23.6 2.4 21.5 457 1,440 22 79 39 228 3.8 21 2.4 13.8 4.6 21.5 13.1 39.0 12.8 90.2 22 117 28 147 6.0 35.8 12.0 80 25 132 94 456 2.0 17.0 1.5 14.0 14.6 51 .8 4.7 2.4 6.7 2.6 8.1 9.4 44.2 2.0 20.7 Mini- mum dis- charge per square mile. South Fork Fortymile River at Franklin.. Fortymile River at Steel Creek Mosquito Fork at Kechumstuk Kechumstuk Creek at mouth Wade Creek at claim "No. 10 above" Fortyfive Pup at claim No. 13 North Fork Fortymile River at "kink"... Steel Creek at mouth Canyon Creek below Squaw Gulch Squaw Gulch at claim "No. 1 above" American Creek at claim "No. 8 above". . . Discovery Fork below Star Gulch Seven tymile River at the falls Flume Creek J mile above mouth Crooked Creek below Eldorado Creek Bii'ch Creek above Twelvemile Creek Birch Creek below Twelvemile Creek Birch Creek below Clums Fork Birch Creek above Sheep Creek Birch Creek at Fourteenmile House Buckley Bar Creek at mouth Porcupine Creek below Bonanza Creek Crooked Creek at Central House Deadwood Creek above Switch Creek Nome Creek above Ophir Creek Troublesome Creek below Quail Creek Minook Creek above Little Minook Creek. . . Hoosier Creek at claim "No. 11 above" Little Minook Creek at claim "No. 9 above" Salcha River at mouth Junction Creek above Moose Lake outlet... Banner Creek at mouth Chena River above Little Chena River Little Chena River above Sorrels Creek Little Chena River above Fish Creek Sorrels Creek above Elliott Creek Elliott Creek at mouth Fish Creek below Solo Creek Fish Creek above Fairbanks Creek Fish Creek at mouth Washington Creek above Aggie Creek Washington Creek below Aggie Creek Aggie Creek at mouth McManus Creek at mouth Chatanika River at Faith Creek. Chatanika River at Poker Creek. Smith Creek above Pool Creek.. . Pool Creek at mouth Faith Creek at mouth New York Creek at ditch intake California Creek at ditch intake Pioneer Creek at ditch intake Hutlinana Creek below Cairo Creek Sullivan Creek above Tofty ditch intake. 1910-1912.. do.... ....do .... do .... do do .... ....do .... ....do.... ....do .... ....do .... do .... ....do .... ....do .... ....do .... ....do .... 1911 1911-12.... 1910-11.... 1911-12.... 1908-1912.. 1911-12.... 1908-1912.. 1909-1912.. ....do .... 1911-12.... 1908-1910.. 1908 1908-9 do .... 1909-10.... 1909-10, 1912. 1909-10.... 1910-1912.. 1907-8, 1910 1908-1910- - 1907-8, 1910 do .... 1910-1912.. 1907-8 1908,1910.. 1908 do .... do.... 1907, 1910- 1912. 1907-8, 1910-1912. 1907-1912.. 1911 do.... 1907-1911- 12. 1908-9 do .... do .... 1908 1908-9 Aug. 2-8, 1910 Aug. 5-11, 1911.... Aug. 2-8, 1910 do July 1-7, 1912 Aug. 1-7, 1910 Aug. 4-10, 1911.... Aug. 1-7, 1910 do Aug. 4-10, 1911.... July 5-11, 1912..... July 4-10, 1910 Aug. 3-9, 1911 Aug. 23-29, 1910... Aug. 1-7, 1910 Aug. 2-8 Aug. 1-7, 1911 Aug. 2-8, 1911 Aug. 3-9, 1911 Aug. 4-10, 1911.... Aug. 3-9, 1911 Aug. 7-13, 1911.... Aug. 5-11,1911.... Sept. 3-9, 1911 Aug. 3-9, 1911 Aug. 12-18,1908... do Aug. 16-22,1909... July 17-22, 1908... Aug. 10-16, 1910... Aug. 15-21,1910... Aug. 14-20, 1910... Aug. 5-11, 1911.... July l.S-21. 1910... Aug. 10-16,1910... do do Aug. 1-7, 1911 Aug. 7-13, 1908.... Aug. 9-15, 1910.... Aug. 7-13 Aug. 6-12 Aug. 7-13 Aug. 1-7, 1911 Aug. 3-9, 1911. do Aug. 1-7 do Aug. 3-9, 1911. Aug. 9-15, 1908.. Aug. 11-17, 1908. Aug. 8-14, 1908.. Aug. 22-28...... Aug. 25-31, 1909. Sec.-ft. 0.049 .088 .055 .064 .038 .067 .104 .018 .118 .019 .087 .068 .292 .470 .087 .133 .138 .084 .103 .101 .031 .061 .028 .057 .195 .157 .2.38 .148 .102 .484 .161 .112 .317 .278 .171 .181 .174 .214 .336 .142 .188 .190 .167 .150 .189 .206 .118 .107 .286 .170 .358 .321 .213 .097 WATER POWER. GENERAL. CONDITIONS. Tlie development of water power in the Yukon-Tanana region, with, the exception of a small plant on Poker Creek, has not gone beyond the period of prehminary investigation. It would be physically pos- sible to develop considerable power on certain streams in this region during the summer months, but it is very doubtful if such an enter- prise would pay. WATER POWER. 327 Aside from a few small lode miines and municipal purposes the market for power at the present time depends entirely on the needs of the placers. In 1912 one dredge was in operation in the Fairbanks district, one in the Birch Creek basin, and three in the Fortymile basin. The total horsepower required to operate these five dredges was probably less than 1,000. The underground placer mines in the Fairbanks district consume considerable power in hoisting the gravel and pump- ing water, but as most of them are operated under separate manage- ment with adequate facilities for developing power already installed it is not likely that their aggregate demand would be more than a few hundred horsepower. Deep placer mining is already declining, and it is doubtful if its needs should be taken into account at all in estimating the future market for hydroelectric energy. More dredges wiU undoubtedly be installed in this region in the future and lode mining will probably increase. The largest steam plant in the Yukon-Tanana region is that of the Northern Commercial Co., at Fairbanks, which furnishes electric light, steam heat, and water service for the town. The plant has an aggregate boiler capacity of 620 horsepower, with an average annual fuel consumxption of about 8,000 cords of wood. The problem of obtaining power is becoming more serious as the fuel supply diminishes. So far wood has been used exclusively for the development of steam, and each year its cost increases because of the greater distance it has to be transported. The economy of a steam plant located in the center of a heavily timbered area to develop electricity for general distribution might be worthy of consideration. The lignites of the Nenana coal fields ^ south of Fairbanks will always offer a possibility for power development and should be care- fully considered before any large water-power installation is under- taken. One of the strongest arguments against the use of water for power in this latitude is the short season that it would be available and the resulting necessity of an auxiliary steam plant to supplement the defi- cient water supply during the spring and auturon and during the low- water periods of the summer, and to supply the total demand from perhaps the middle of November until the middle of May. During 1909-10 a hydroelectric plant with a maximum capacity of 10,000 horsepower was installed in the Yukon Territory on Klon- dike Kiver, about 25 miles from Dawson. The water is diverted from North Fork of Klondike River and carried in a ditch for several miles into Klondike River valley, where a head of 234 feet is obtained. Nothing definite is known regarding the success of the plant, but the iCapps. S. R., The Bonnifield region, Alaska: U. S. Geol. Survey Bull. 501, pp. 54-62, 1912. 328 SURFACE WATER SUPPLY OF YUKON-TANANA REGION, ALASKA. similarity of the climatic and economic conditions under which it was built and is operated to those existing in the Yukon-Tanana region and the fact that it is the only hydroelectric plant of conse- quence yet installed that does come under those conditions, should make it invaluable as an object lesson for prospective investors. A small hydroelectric plant was installed on Poker Creek about 30 miles from Fairbanks in 1907-8. The water was obtained from Poker, Little Poker, and Caribou creeks and carried to a point on Chatanika River, where a head of about 80 feet was obtained. It is understood that the plant was not successfully operated because of tack of water and various other reasons peculiar to management and operation. The streams of the Yukon-Tanana region are subject to large variations in flow. The maximum discharge may be several hundred times the minimum. Most of the ice and snow that accumulates in the winter melts during May and June. If the excess water of that period could be stored and Tendered subject to power demands several streams on which the minimum flow is naturally too low to permit economic development might offer favorable possibilities. There are, however, no natural reservoir sites or lakes at a sufficient elevation that could be used for storage. The grades of the streams are remarkably uniform, showing very few concentrated falls of consequence. Pressure would have to be obtained by carr3ring the diverted water in ditches or pipes for a distance sufficient to furnish the required head. POWER SITES. FORTYMILE RIVER BASIN. Near the headwaters of the tributaries of Fort37-mile River there are a number of points where the streams have considerable grades and might furnish feasible sites for water-power plants, if the demand were ever sufficient. However, at most of these sites the summer minimum is so low that it would seriously hamper operations. The basin offers no adequate storage possibilities. At present the most likely market for hydroelectric power appears to be offered by the possible installation of dredges on Chicken Creek, Wade Creek, South Fork, and the main Fortymile below the forks. Most available for supplying such a market are the following: On Dennison Fork in the vicinity of the forks, 12 miles above the mouth, the topographic map shows a fall in the stream of about 200 feet in 10 miles. A portion of this fall might be capable of development by a ditch diversion to a lower point in the valley. The minimum flow in summer is approximately 100 second-feet. U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 342 PLATE IX A. NORTH FORK OF FORTYMILE RIVER AT THE "KINK." B. FALLS ON SEVENTYMILE RIVER. WATER POWKB. 8^9 Between the mouths of Kechumstuk and Chicken creeks, in a distance of about 28 miles, Mosquito Fork falls 600 feet. The fall is greatest in the upper portion, where the stream emerges from the old valley floor above Kechumstuk and enters the present one, and the topography and geologic formation seem better suited for eco- nomical ditch construction in this portion than lower down. It is estimated that about 12 miles of ditch diverting from the left of Mosquito Fork below the mouth of Kechumstuk Creek would carry water to a point near the mouth of Gold Creek where a head of 100 to 150 feet would be available. The minimum flow is approximately 45 second-feet. This supply might be augmented by a ditch about 8 miles long, diverting from Gold Creek, which probably has a mini- mum of about 10 second-feet. A head of 100 feet and a minimum flow of 55 second-feet should be capable of producing 500 horsepower for 5 months of the year. The flow of Mosquito Fork is shown in the tables. (See p. 77.) On North Fork two points ofi^er possibilities for power development. About a mile below the union of North and Middle forks there is a rapids in which the river has a very sharp grade for a short distance, but its amount is not known. The river at this point has a flow practicaUy the same as that at the ''kink." (See p. 95.) About 10 miles below the junction of North and Middle forks, the river formerly followed a large meander locally known as the ''kink." Although the distance around it was 2| miles, the two channels at the neck of the meander were separated by a sharp rock ridge only about 100 feet high and about 100 feet wide at the water level. Several years ago a channel was blasted through the rock ridge to divert the water and thus drain the meander for mining. A fall of about 17 feet was thus concentrated in a horizontal distance of about 100 feet. A view of the "kink" is shown in Plate IX, J.. The minimum discharge of North Fork is estimated at about 200 second-feet, and this with an available head of 17 feet should be capable of supplying 300 horsepower from about May 15 to October 1. A large portion of the season the flow would be greater. (See horse- power table, p. 332.) SEVENTYMILE RIVER BASIN. From Diamond Fork to the mouth, a distance of about 53 miles following the general trend of the valley, Seventymile River has ^ fall of over 2,000 feet. From Diamond Fork to Barney Creek it falls 1,400 feet in 25 miles. There are no concentrated falls in this stretch, but ditches diverting at favorable points could make available considerable fall in comparatively short distances. At a point about one-half mile below Washington Creek the river passes into a rock 330 SURFACE WATER SUPPLY OF YUKON-TANAKA REGION, ALASKA. canyon, where it falls rapidly for about 300 feet and has a concen- trated fall of about 9 feet. (See PL IX, B.) The head which could be developed is about 15 feet and probably 200 horsepower could be depended upon throughout the summer. (See horsepower table, p. 332.) There is no present power market in view on Seventymile River. There is considerable wood for fuel in the basin and this would probably furnish the most economical source of power for many years. BIRCH CREEK BASIN. Records of stream flow have been kept in the Birch Creek basin at various points since 1908. They show that a very low run-off should be expected for about a month during the middle of the summer. There is also a period of low flow in the fall before the freeze-up. The creek falls 1,000 feet between the mouth of Twelvemile Creek and a point in the flats about 15 miles below South Fork. The distance is about 70 miles by map measure. The topographic map shows a fall of about 20 feet per mile in the vicinity of Great Unknown Creek and Clums Fork ; also for several miles above and below the South Fork. There is no doubt but that considerable power could be developed for three or four months each summer (see table, p. 332), but the conditions along the stream are not very favorable for ditch construc- tion. Considerable rock work or fluming would have to be done. CHATANIKA RIVER BASIN. Chatanika River offers perhaps the most favorable opportunity for hydroelectric development of any of the streams in. Fairbanks district. By constructing a ditch for 12 or 15 miles along the river, diverting water from a point near the junction of Faith and McManus creeks, a head of about 400 feet could be obtained. Daily records of stream flow were kept at this point during parts of the summers of 1907-8 and 1910-1912. (See p. 281.) The minimum flow recorded during that period was 24 second-feet from August 4 to 8, 1911. From 800 to 1,000 horsepower could probably be developed at this point from the later part of May until the later part of September. (See table, p. 332.) A transmission line about 40 miles in length would reach the center of the mining district. From Kokomo Creek to Poker Creek, a distance of about 10 miles, the river drops 100 feet. Daily records of stream flow were kept at Poker Creek during the summers of 1907-1912. (See p. 285.) The minimum recorded flow was 87 second-feet, which could produce from 700 to 800 horsepower under a 100-foot head. (See table, p. 332.) From Faith Creek to Eldorado Creek, a distance of about 50 miles the river falls through a height of about 800 feet. WAa:ER POWER. 331 WASHINGTON CREEK. Washington Creek has been considered as a source of power. During 1908 daily records were kept at the junction of Aggie Creek, below which there is a fall of approximately 200 feet in about 8 miles. The records, however, indicate an insufficient supply for power development, unless considerable storage could be provided, which probably would not be feasible. CHENA RIVER BASIN. No particularly favorable opportunities for water-power develop- ment are laiown to exist in the Chena River basin. From a study of the topographic map the Chena shows a relatively high gradient above North Fork, but the stream-flow data are hardly sufficient to warrant any estimate of the power that could be developed. In the Little Chena basin considerable study of the water supply was made in 1907, 1908, and 1910. It was proposed to gather the water from the upper tributaries at an elevation of about 900 feet, and convey it by ditch line to a point in the lower dra^inage area on the right bank of the river, where a fall of about 200 feet could be obtained. The water supply was found to be entirely inadequate. SUMMARY. The records of stream flow at points showing the greatest possibility for water-power development have been briefly summarized in the table below. In comparing the columns showing days of deficient discharge for several years on any stream, allowance should be made for the difference in the length of periods and also for the part of the season covered by the records. Ordinarily the longer the period the greater will be the number of days of deficient discharge for any given number of horsepower and the less favorable will be the comparison with some other year in which the records extend over a shorter length of time. Also the days of deficient discharge will be a greater per- centage of the total number of days if the observations include only the low-water months. The table gives the horsepower (80 per cent efficiency) per foot of fall that may be developed at different rates of discharge and shows the number of days on which the discharge and the corresponding horsepower were respectively less than the amounts given in the colunms for ''discharge" and ''horsepower." 332 SURFACE WATER StJPPLY OF YtTKOK-TAlTANA REGION, ALASKA. Estimated discharge and horsepower for North Fork of Forty mile and Seventyrnile rivers for 1910-1912. Horsepower per foot fall (80 per cent efficiency). Days of deficient discharg 3. Discharge in second-feet. North Fork of Fortymile River at the "kink." Seventyrnile River at the falls. July 9 to Sept. 23, 1910. May 19 to Sept. 20, 1911. May 5 to Oct. 13, 1912. June 16 to Sept. 30, 1910. June 20 to Sept. 5, 1911. May 3 to Oct. 18, 1912. 110 10 12 14 16 18 20 22 24 26 28 30 35 40 5 16 30 42 43 47 50 57 61 64 71 74 132 154 1 3 5 9 10 10 17 19 22 23 3 176 6 198 4 10 16 22 31 33 49 57 8 220 1 4 7 11 17 25 35 13 242 19 264 22 286 26 308... 60 330 2 4 63 385 96 440 101 Estimated discharge and horsepower for ChataniJca River and Birch Creek for 1907-1912. Horse- Days of deficient discharge. power Birch Creek per Chatanika River below Faith Chatanika River below Poker above Discharge in second- feet foot fall (80 per Creek. Creek. Sheep Creek. cent June July May May May June May May May May June Jiuie May effici- 21 to 13 to 25 to 24 to 15 to 20 to 16 to 9 to 17 to 6 to 13 to Ito 8 to ency). Sept. Sept. Sept. Sept. Sept. Oct. Oct. Oct. Oct. Nov. Oct. Sept. Sept. 30, 30, 25, 24, 30, 14, 21, 5, 29, 19tl. 26, 30, 22, 1907. 1908. 1910. 1911. 1912. 1907. 1908. 1909. 1910. 1 1912. 1911. 1912. 22 2 2.5 3 4 5 6 7 8 9 10 12 14 6 14 22 25 36 45 54 62 67 71 74 28 33 13 16 29 39 47 52 56 69 73 44 ""'"6" 2 4 19 35 57 14 29 34 37 39 45 47 54 55 12 21 32 39 49 64 75 66 77 4 11 24 30 41 ""6" 3 7 13 20 23 88 2 5 17 26 2 3 22 40 99 110 132 154 176 16 77 58 64 76 85 5 27 49 44 3 24 198 18 78 65 69 77 90 17 5 39 55 59 16 29 220 20 82 66 79 79 98 27 27 46 60 66 31 32 g HYDRAULIC METHODS. The methods of mining that have been practiced in the Yukon- Tanana region have not as a rule required the use of large quantities of water under pressure. Several small hydraulic plants have been installed, but the value of the gold recovered by such means is relatively small. They are briefly described in connection with the basins in which they are located. HYDEAULIC METHODS. 333 Nearly all the areas now being worked by hydraulic methods are creek deposits in which the gold-bearing gravel Ues at shallow depths. The bench deposits so far known are few and small. The gradients of the bedrock that underhes the creek deposits are inva- riably too low to pemiit hydraulicking without elevating the gravel. Hydraulic elevators require about twice as much water to raise the gravel as is needed to deliver the material to it. A few small ones have been installed and operated in this region, and without exception they have proved unsuccessful. A system of raising the gravels to the sluice boxes that is now being practiced by three plants in the Birch Creek basin has been found to be superior to elevators, at least under the conditions in that section. The plant on Mammoth Creek, the largest of the three, was described in a pre^dous report ^ as follows: Mammoth Creek has a very low grade, and in order to overcome this difficulty a plant was installed which is novel in Alaska but is identical in principle to the one installed on Eagle Creek in 1908. The general plan of operation is as follows: First, a bedrock drain is excavated to dispose of the water in the cut and to carry away the overlying muck, which is hydi'aulicked off from the gravels to be handled by the first set-up. A channel is then groundsluiced back of and above the cut and opposite the hydraulic giants. In this channel substantially constructed sluice boxes (with block riffles), similar in design to those ordinarily used in hydraulicking, are set up with a grade depending on the character of the gravels to be washed. A sheet-iron back stop about 10 feet high is then erected back of and against the boxes. The auiifer- ous gravels are driven directly by the water from the nozzles of the giants against the back stop, from which they drop into the sluice boxes. A gravel incline is formed in front of the boxes by the stream of water as soon as operations are begun, and for this reason the force of the moving gravel is not expended against the sides of the boxes. The water for transporting and washing the gravel, after it is dropped into the boxes, is diverted from the creek about 1 mile above and carried in a ditch to the head of the sluice and after passing through is carried away in the bedrock drain. The tailings which accumulate at the end of the sluice are "piped" back out of the way by a separate giant set up at any convenient place. It is not ordinarily necessary to operate this giant continuously. The frequency with which the tailings have to be moved depends on the dumping room at the end of the boxes and the rate at which the gravel is being moved. This process does, however, require a quantity of water which should be taken into account in considering the supply necessary for such a system. This method is especially adapted to working creek deposits with medium depths of gravel, where the slope of the bedrock is insufficient to permit the removal of the taihngs by gravity. It has several advantages over elevators. The initial expense is less and the water required is less. No such heavy parts are required, which is an important item, especially in the more remote districts, where transportation is always expensive and often uncertain. The cost of set-ups is not as great and the chances of delay incident to repairs and replacement of parts are no greater than in ordinary hydraulicking. The system includes about 10 miles of ditch (see p. 182), the longest in the Yukon-Tanana region. Many other ditches have been built, 1 Ellsworth, C. E., Placer mining in the Yukon-Tanana region: U, S. Geol. Survey Bull. 442, pp. 236- 237,1909. 334 SURFACE WATER SUPPLY OP YUKON-TANANA REGION^ ALASKA. but they are relatively small and experience in such, work has been rather slight. On Seward Peninsula over 400 miles of ditch with a capacity of 20 second-feet or greater has been built. Frozen ground has caused serious difficulties there as well as in the Yukon-Tanana region. (See p. 183.) Methods of construction and means of overcoming difficulties have been described by Heashaw and Parker^ as follows: Ditches are constructed by several different methods, according to the conditions of the ground encountered. Horses have been used for the work wherever possible. In one method the ground is first prepared by removing the moss and turf from a strip 40 or 50 feet wide on either side of the ditch. This should be done, if possible, the summer before actual construction is begun, in order that the ground may thaw more readily. Actual construction begins with plowing, after which some of the ma- terial is moved with a grader from the upper side of the ditch to the lower bank until a practically flat bench is produced. The cut is then excavated with horse scrapers down to grade, and the material piled up on the lower bank. The ditch is finished by hand, and both bottom and bank are trimmed to an even grade and alignment. The method above described is practicable where the ground contains only small or medium sized rocks and is about the cheapest and most rapid that can be used, but it requires exceptionally favorable conditions to make it a success. Where the ground is naturally unfrozen or can be made to thaw easily, and where other conditions are similar to those encountered in a temperate climate, no difficulty is experienced. T\Tierever the ground is frozen muck, or so-called glacier, it melts rather slowly when exposed to the air, and the work of excavation must be done by hand while it thaws. The best practice is to keep exposed as large an area as possible and to remove the soil in thin layers. Practically all of the ditches north of the mountains were built by this method. More or less rock work has to be done on all ditches. Some of them have had to pass around cliffs of practically solid rock where the construction required, a large amount of blasting. Rock cuts offer no problems not met in other fields except in the method of making the ditch tight, which is done by the use of a peculiarly tough and tenacious sod abundant in many places in the north. The sod is cut with mattocks into pieces 1 to 2 feet square and placed in the ditch, bottom up. Two layers are usually placed in the bottom, breaking joints as well as possible, and the whole is carefully and solidly tamped into place. The sides of the ditch are made tight with a sod wall, the pieces being laid one above another, bottom up. Where the sod is above the water line part of the time, the grass usually continues to grow and its living roots bind the material more closely and firmly together. The best sod, and the only kind which fully meets the requirements, is that containing grass roots and very little moss, for the moss is less tenacious and decays more rapidly. Grass, however, is not abun- dant in many places, and it is therefore often necessary to use sod of inferior quality, with correspondingly unsatisfactory results. For example, on the Fairhaven ditch there is a great deal of rockwork and much frozen ground which becomes very soft on thawing, and a great deal of sod was needed. Sod could be found only in small isolated patches, and much of it had to be taken from the river bottoms far below the line of the ditch at considerable expense. In the Kougarok region, however, sod is fairly abundant and has been used very freely, and in southern Seward Peninsula eod of a good quality can usually be found. 1 Henshaw, F. F., and Parker, G. L., Surface water supply of Seward Peninsula, Alaska: U. S. Geol, Survey Water-Supply Paper 314, pp. 258-260, 1913. HYDEAULIC METHODS. 335 Canvas has been used in some places to line ditches, but it is expensive and is reported to be not wholly satisfactory. If it is disturbed after it is once laid down, it is likely to be torn, in which event it becomes practically useless. In ground composed largely, of frozen muck or ground ice special methods and pre- cautions must be used. This material when it thaws leaves a soft residue, largely mud and decomposed vegetable matter, which may be only 20 or 30 per cent of the original volume. Water flowing across such material causes it to thaw rapidly, and con- sequently when a ditch is built thi'ough it precautions must be taken to prevent too much thawing. Where the muck is present the portion nearest the surface usually contains much more earthy matter than that just below, and in many places there is a layer of blue clay just beneath the moss. The vegetable matter close to the surface is also less completely decayed and therefore more solid and tenacious than that lower down. If this sui'face covering is allowed to remain in place and the ditch built over it by building up the lower bank with sod and with material stripped from the top, good results can usually be obtained. WTien the stripping is carried to just about the right depth, the water, after being tiu'ned into the ditch, will cause the ground to thaw a little. The bottom will settle a few inches, and then the ditch practically builds itself, so that eventually the water is carried in a section entirely below the surface of the ground, and the ditch can not leak, because its sides are all soft, finely divided material, mostly muck and clay, backed by solid and impervious frozen ground. These ideal conditions are generally aimed at by ditch builders, but are attained only at certain localities and by special care in building and watchfulness in maintaining the ditch. Most of the Fabhaven ditch was built in 1906, before builders had gained much experience with ground of this character. Through most of its course it passes over ground that generally is permanently frozen. The ditch was built under a contract which called for a cut of 12 inches below the ground surface of the lower bank, and the contractors were held rigidly to the specifications. As a result, ail the surface covering was removed, and the ditch bottom was made in frozen ground containing only a small percentage of solid material. When the water was turned in this frozen muck thawed and the ditch settled in some places 3 or 4 feet. The material thus melted yielded enough solid matter so that in many places a fairly good bottom resulted and the thawing did not progress any farther. At other points the ditch bottom practically sank "out of sight." The water cut under the lower bank and bad breaks resulted. The Candle ditch -^^ * * was built in a drainage basin adjacent to that in which the Fairhaven ditch is located and encountered much ground of a similar character, but apparently containing a somewhat higher percentage of solid matter. It is smaller than the Fairhaven ditch and was built with a cut on thQ lower bank of about 8 or 9 inches. This ditch has settled in a great many places, but when the writer last visited it, in 1909, it was on the whole in somewhat better condition than the Fairhaven ditch. In one section where the ground had cut badly the ditch had evidently been given an excessive grade, and the water attained a velocity sufficient to scour away the fine material as it thawed. As a result a deep cut was eroded, and only the fact that this occurred on flat ground prevented a bad break. The necessity of keeping the grade of the ditch and the velocity of the water low in ground of this character is very important and can not be too strongly emphasized. The Fairhaven ditch was laid out with a grade of 4.22 feet to the mile, and as it was designed to carry water to depths of 2 feet or more the resulting velocities were rather high, a condition which contributed in no small degree to the cutting that resulted in the soft ground. The grade of the Candle ditch was only 3.69 feet to the mile and the ditch itself is of smaller dimensions, so that the resulting velocities were lower and the difficulties encountered correspondingly less. 336 SURFACE WATER SUPPLY OF YUKON-TANANA REGION, ALASKA. In many places a ditch in ground of this character should not be given a grade greater than 2^ feet to the mile. The ditch can be built wide and with a shallow cut. It will then "make itself" at a very small expense, and the low velocity resulting will tend to give a permanent and satisfactory waterway. The Miocene ditch is described as follows: ^ One of the most notable examples of successful flume construction over frozen ground that has been seen by the writer is that on the Miocene ditch. This flume is 1,100 feet long and has a width of 8 feet and a depth of 28 inches. It was constructed in 1901, and until 1906 or 1907 it retained practically. perfect alignment, both horizontal and vertical. No extensive repairs were necessary on it until 1909. In putting in the foundation trenches were dug 3 or 4 feet in the frozen ground, which was practically all ice. A sill was laid in the bottom of the trench and the uprights fastened to this sill. The excavated material was then replaced in the trenches and allowed to freeze again into its original condition. Sod was carefully placed over the trench, the uprights were then sawed off to grade, and the flume constructed on them. Even with all these precautions, however, at the end of about eight years the flume was in such bad shape that extensive repairs had to be made. Seepage losses ^ on ditches in Seward Peninsula have been found to be a serious factor and should be taken into account in planning a water supply. The average loss per mile under varying conditions of supply, size, character of ditch, and cUmate was about 0.5 second- foot. The actual loss per mile varies from almost no loss at all to as much as 1 second-foot and in a few places where unusually porous soil was encountered to even greater amounts. CONCLUSIONS. Scope. — ^The conclusions of this report in regard to the water supply and factors controlUng it in the Yukon-Tanana region are summarized below. They are only intended to present concisely the general conditions in this region and are necessarily incomplete. They represent the writer's interpretation of the available data and the natural conditions and for a more comprehensive presentation one is referred to the published records and the discussions thereof. To'pografhy. — Characteristically, the region is a dissected upland. From a distance it appears hilly or mountainous, but in reality its predominating feature is a series of long branching ridges of remark- ably uniform elevation. This Idnd of topography is essentially unfavorable for mining pur- poses — ^first, because of the small catchment area above the diversion point of the stream on which the mine is located; second, because of the absence of large adjoining basins lying above the general level of the mines from which the immediate supply can be augmented by reasonable length ditches or pipe hues ; third, because of the absence of natural storage basins; and fourth, because of the low uniform stream grades. 1 Henshaw, F. F., and Parker, G. L., op. cit., p. 262. 2 Idem, pp. 263-269, CONCLUSION. 337 Temperature. — The temperattire is characterized by extreme ranges, both annual and monthly. Summer temperatures above 90° and winter temperatures below —70° have occasionally been reported. The mean monthly temperature is below 32° for seven months of the year, and a large portion of the area is permanently frozen to great depths. This condition is an obstacle to ground storage, for it tends to cause the rainfall to run directly into the streams, resulting in a less uniform distribution of the run-off, and consequently a very "flashy" and widely fluctuating stream flow almost directly dependent upon precipitation. Because of the low temperatures the evapora- tion is probably much less than in the more southern latitudes. Precipitation. — The estimated mean annual precipitation of the region is about 12 inches. The annual precipitation at a certain point varies between relatively wide hmits as does also the precipi- tation at different points for the same year. Approximately 60 per cent of the annual precipitation falls dinging the four months, June, July, August, and September, in rather Hght general rains and fre- quent small showers. The favorable distribution of the rainfall is largely counteracted by its small amount and by various unfavorable conserving factors. Vegetation. — The average elevation of timber Hne is about 2,500 feet above sea level. Spruce is the most common, and in the valley bottom near the watercourses much of it attains diameters of 18 to 24 inches. Back from the watercourses and on the valley slopes it is usually stunted and is seldom suitable for milhng, but has fur- nished a fair supply for fuel. White birch is common on southern slopes at low elevations, and small stands of cottonwood are found along many of the larger streams. Dense growths of alder and willows fringe the smaller streams and occupy the higher gulches and ravines. The supply of wood suitable for fuel or lumber has been greatly depleted by fires and near the centers of development is being rapidly exhausted by industrial uses. The amount of moisture absorbed by vegetable growth is probably less than in more southern latitudes. Normally the ground is nearly everyw^here covered by a thick mantle of moss, which, where not destroyed by fire, undoubtedly aids in regulating the stream flow. Water supply. — The water supply or run-off is a function of several factors, the more important of which are precipitation, temperature, topography, vegetation, and evaporation. In the Yukon-Tanana region the stream flow resulting from these factors is generally unfavorable for hydrauUc development. The winter supply is entirely inadequate for any mining, except perhaps for working small lodes. In fact, on many of the streams it is practically nil. In summer the 42913°— WSP 342—15 22 338 SUEFACE WATER SUPPLY OF YUKON-TAN^ ANA EEGION, ALASKA. stream flow fluctuates widely, with a great sensitiveness to the rain- fall, so that during periods of deficient rainfall the run-ofl becomes relatively" very low. This characteristic is of great practical impor- tance because thereby the controlling consideration in most hydraulic development in this region becomes the question of the minimum flow. The records of minimum weekly run-off in second-feet per square mile from, representative drainage areas have been summarized and discussed on pages 325 and 326, and they are worthy of careful study. Water power. — ^The conditions of the Yukon-Tanana region are particularly unfavorable for the development of water power. The combinations of low minimum rim-ofl (see p. 326) without natural storage or favorable means of developing artificial storage, of low and uniform stream grades, of short seasons, and of variable market make the use of water power a last resort. Hydraulic mining. — The uniform topographic features, low mini- mum run-off, lack of storage faciUties, and low stream gradients, just indicated as the principal objection to the development of water power, are probably of more serious consequence in hydrauHc mining because for such uses the point at which the water must be dehvered under pressure is wherever the gold occiu*s, whereas water power may be generated many miles from where it is to be used and transmitted in the form of electric energy. There may be gold deposits in this region that can be recovered more economically by hydrauhc methods than by other means, but the two most important factors in the operation of a hydrauHc plant are not naturally available. The first requirement, an ample water supply under a sufiicient head, is everywhere expensive and in some locahties is practically impossible to obtain. The second and almost equally important factor, a natural stream grade sufficient to remove the tailings without elevating the gravel, is nowhere available except for bench deposits, which so far as known are of minor importance in this region. INDEX. A. Page. Acme Creek, miscellaneous measurements of. 181 Aggie Creek at mouth 275 Albert Creek, miscellaneous measurements of 212 Alder Creek at claim "No. 7 above" 140-143 Allen Creek, miscellaneous measurements of. 314 Altitudes of mountain ranges 17 American Creek at claim ''No. 8 above". . . 122-125 at United States pumping plant 125 Anderson, C. E . , work of 12 Applegate Creek, miscellaneous measure- ments of 322 Aubiim Mining Co.'s camp. Dome Creek at. 109-110 B. Bachelor Creek below Costa Fork. 178-179 miscellaneous ir.easuren:ents of 181 Baker Creek at road crossing 307-308 North Fork of, miscellaneous measure- ments of 314 Baker Creek drainage basin, description of. 306-307 miscellaneous measurements of 314 stream flow in 306-322 Banner Creek at mouth 235-237 miscellaneous measurements of 237 Barney Creek above ditch intake 143-144 miscellaneous measurements of 154 Barney Creek ditch below the forks 144-145 Bear Creek, miscellaneous measurements of 105, 180, 181, 217,270 Beaver Creek, miscellaneous measurements of 217 Beaver Creek drainage basin, description of. 212-213 miscellaneous measurements of 217 stream flow in 212-217 BeUe Creek, miscellaneous measurements of. 303 Big Windy Creek, miscellaneous measure- ments of 181 Birch Creek above Twelvemile Creek 156-157 above Sheep Creek 162-164 at Fourteenmile House 164-169 below Clums Fork 160-162 below Great Unknown Creek 159-160 below Twelvemile Creek 157-159 estimated discharge and horsepower for. 332 North Fork of, miscellaneous measure- ments of 181 South Fork of, miscellaneous measure- ments of 181 Birch Creek drainage basin, description of. 155-156 miscellaneous measurements of 180-181 stream flow in 155-181 Bonanza Creek above ditch intake 192-194 below ditch intake 194-1 9 Page. Bonanza ditch at intake 206-208 below junction with Porcupine Branch. . 209 near outlet 210-211 Boston Creek, miscellaneous measurements of 303 Boulder Creek, miscellaneous measurements of 212 Break-up and freeze-up on St. Michael Bay. . 22 on tributary streams of Yukon River 22 on Yukon River 21-22 Brigham Creek, miscellaneous measurements of 217 Broken Neck Creek, miscellaneous measure- ments of 154 Brooks, A. H. , work of 12 Bryan Creek, miscellaneous measurements of 217 Bryant Creek, miscellaneous measurements of • 154 Buckeye Creek, miscellaneous measurements of 237,271 Buckley Bar Creek at mouth 174-176 Buckskiu Creek above Fortyfive Pup 88-90 miscellaneous measurements of 94 Bullion Creek, miscellaneous measurements of 105 Butte Creek, miscellaneous measurements of. 180 C. Cache Creek, miscellaneous measurements of. 324 California Creek at ditch intake. . .■ 310-311 Camp Creek, miscellaneous measurements of. 119 Canyon Creek below Squaw Gulch 113-116 miscellaneous measurements of 119, 237 Caribou Creek, miscellaneous measurements of 303 Cassia Creek, miscellaneous measurements of. 303 Champion Creek, miscellaneous measure- ments of 105, 217 Chapman Creek, miscellaneous measurements of 233 Charity Creek above Homestake Creek 297-299 miscellaneous measurements of 303 daily precipitation at 34 Chatanika ditch near outlet 291-292 Chatanika River below Faith Creek 280-285 below Poker Creek 285-291 estimated discharge and horsepower for. 332 hydrograph showing daily discharge oT. 286 (PI. VIII) miscellaneous measurements of 302 Chatanika River drainage basin, description of 276-277 miscellaneous measurements of 302-303 stream flow in 276-303 339 340 INDEX. Page. Chatham Creek, miscellaneous measiirements of 303 Chena River above Little Chena River 245-248 above Shamrock Creek 244-245 North Fork of, below Monument Creek. 249-250 miscellaneous measurements of 251 South Fork of, above Monument Creek. 248-249 West Fork of, miscellaneous measure- ments of , 251 Chena River drainage basin, description of. 243-244 miscellaneous measurements of 251 stream flow in 243-270 Chicken Creek, daily precipitation at 35 miscellaneous measurements of 94 Circle Hot Springs, miscellaneous measure- ments of 212 Circle quadrangle, reconnaissance map of.. In pocket (PL XI) Claim "No. 6 below," Goldstream Creek at. 304-305 Claim "No. 7 above," Montana Creek at. . . 102-104 Claim "No. 8 above," American Creek at. . 122-125 Claim "No. 9 above," Independence Creek at 195-196 Claim "No. 10 above," Wade Creek at 85-88 Claim "No. 11 above," Hoosier Creek at. . . 229-232 Claim No. 13, Fortyfive Pup at 91-93 Claim " No. 17 above," Hunter Creek at 232 Cleary , daily precipitation at 33 Clear y Creek , miscellaneous rpeasurements of . 303 Climate of region 18-41 Clums Fork below Munson Creek 172-173 miscellaneous measurements of 181 Comet Creek , miscellaneous measurements of . 105 Confederate Creek at mouth 98 Costa Fork, miscellaneous measurements of. . 181 Covert, C. C.,workof 12 Cripple Creek, miscellaneous measurements of 303 Crooked Creek above Eldorado Creek 149-151 at Central House 188-192 daily precipitation at 36 miscellaneous measurements of 181, 303 Crooked Creek drainage basin, description of 181,182 miscellaneous measurements of 212 stream flow in 181-212 Current meters, description of 52 views of 52 (PI. Ill) Curtis Bar Creek, miscellaneous measure- ments of 154 D. Data, accuracy of 56, 57 use of 54-56 Davenport, R. W., work of 13 Davis Creek, miscellaneous measurements of. 94 Deadwood Creek above Switch Creek 200-204 Deep Creek, miscellaneous measurements of. 94, 154, 303 Dennison Fork of South Fork of Fortymfle River at mouth 68-69 Dick Dole Creek, miscellaneous measure- ments of . . - 119 Discharge measurements during winter 47 Discovery Creek, miscellaneous measure- ments of 119 Discovery I'ork of American Creek below Star Gulch 127-130 daily precipitation at 37 Division of work, details of 12, 13 Dome Creek at Auburn Mining Co.'s camp. 109,110 Dome Creek ditch, miscellaneous measure- ments of 303 E. Eagle, daily j)recipitation at 25-28 monthly temperature at 19 Yukon River at 62-66 view of 62 (PI. V) Eagle Creek, hydraulicking on, view show- ing 63 (PL VI) Miller Fork of, miscellaneous measurements of 180 Eldorado Creek, miscellaneous measurements of 303 Elephant Gulch, miscellaneous measurements of.: 322 Elliott Creek near mouth 259, 260 Ellsworth, C. E., work of 12, 13 Equivalents, convenient, list of. 50 Eureka Creek drainage basin, description of. . 315 miscellaneous measurements of 318 stream flow in 315-318 Eureka Creek, miscellaneous measurements of 318 Fairbanks, daily precipitation at 28-31 monthly temperature at 19,20 Fairbanks Creek, miscellaneous measure- ments of 270 Fairbanks quadrangle, recormaissance map of In pocket (PL XII) Faith Creek at mouth 295-297 daily precipitation at 33 Fiftymile River at Whitehorse, Yukon Territory 67 Fish Creek at mouth , 266-268 above Fairbanks Creek 264-266 below Solo Creek 261-264 Fish Creek, miscellaneous measurements of. . 180 Flat Creek, miscellaneous measurements of. . 303 Flume Creek, one-fourth mile above mouth . 137-139 Flume Creek ditch, miscellaneous measure- ments of 154 Fortyfive Pup at claim No. 13 91-93 Fortymile quadrangle, reconnaissance map of In pocket (PI. X) Fortymile River at Steel Creek 73-76 below Steel Creek, view of 62 (PL V) North Fork of, at the " kink" 95-96 above Middle Fork 97 drainage basin of, description of 94-95 miscellaneous measurements in. . 105 stream flow in 94-105 estimated discharge and horsepower for 332 main stem of, description of 68 South Fork of, at Franklin 70-73 Dennison Fork of, at mouth 68-69 drainage basin of, description of 70 miscellaneous measxirements in.. 94 stream flow in 70-94 Mosquito Fork of, Kechumstuk 76-78 Fortymile River drainage basin, description of 67-68, 105-106 miscellaneous measurements in 119 stream flow in 67-119 INDEX. 341 Page. Fossil Creek, miscellaneous measiirements of. 217 Fox Creek at Rclf 's claim 151-153 noiscellaneous measurements of 306 Frankitn, South Fork of Fortjonile River at. 70-73 Frozenfoot Creek, miscellaneous measure- ments of 251 Fryingpan Creek below forks 170-171 G. Gaging stations, location of, key map show- ing 56 (PI. IV) regular, in the region 57-60 Geography of region 17 Geology of region 17-18 Gilmoro Creek, miscellaneous measurements of 306 Gofli Creek, miscellaneous measurements of. . 322 at mouth 81-82 Gold Creek at mouth 81-82 miscellaneous measurements of 94 Golddust Creek, miscellaneous measurements of 180 Goldstream Creek at claim " No. 6 below " - 304-305 Goldstream drainage basin, description of. 303-304 miscellaneous measurements of 306 stream flow in 303-306 Goose Creek, miscellaneous measurements of. 271 Granite Creek, East Fork of, miscellaneous measurements of 154 miscellaneous measurements of 154, 233 West Fork of, miscellaneous measure- ments of 154 Great Unknown Creek at mouth 171-172 Greul, Louis, work of 13 H. Hall Creek, miscellaneous measurements of. . 119 Harris, Martin, work of -. 13 Harrington Fork, miscellaneous measure- ments of 181 Harrison Creek, miscellaneoxis measurements of 181 Helm Creek, miscellaneous measurements of. 270 Hess Creek drainage basin, description of. . 217-218 miscellaneous measurements of 222 stream flow in 217-222 Homestake Creek at mouth 299-301 Hoosier Creek at claim "No. 11 above" 227-229 Hope Creek, miscellaneous measurements of. . 302 Hoyt, J. C, work of 13 Hunter Creek at claim "No. 1 7 above " 232 miscellaneous measurements of 233 Hutchinson Creek below Confederate Creek. 98-100 below Montana Creek 100-102 miscellaneous measiorements of 105 Hutlinana Creek, miscellaneous measure- ments of 322 near Cairo Creek 320-322 Hutlinana Creek drainage basin, description of -^ 319-320 Hydraulic methods in use 332-336 Hydraulic mining in region 338 Hydraulicking on Eagle Creek, view show- ing 63 (PI. VI) Hydrograph showing daily discharge of Cha- tanika River 286 (PI. VIII) I. Page. Independence Creek at claim "No. 9 above'' 195-196 miscellaneous measurements of 212 J. Joslin, Falcon, work of 13 Junction Creek above Moose Lake outlet . . 240-243 Juniper Creek, miscellaneous measurements of 303 K. Kechumstuk Creek at mouth 79-81 Kechumstuk, Mosquito Fork of Fortymile River at 76-78 King Solomon Creek at Liberty Cabin 106-108 Kokomo Creek above Alder Creek 301-302 Koonce, M. E., work of 13 L. Lawson Creek at mouth 173-174 Liberty Fork at mouth 108-109 Little Chena River above Sorrels Creek 252-254 below Fish Creek 255-257 Little Chena River drainage basin, descrip- tion of 251-252 miscellaneous measuretnents of 270 stream flow in 251-270 Little Minook Creek, view of 218 (PI. VII) Little Minook Junior Creek, miscellaneous measurements of 233 Little Poker Creek, miscellaneous measure- ments of 303 Little Salcha River, miscellaneous measure- ments of * 237 M. McConaughy, C. W., work of 13 McKay Creek, miscellaneous measurements of 303 McLean Creek, miscellaneous measurements of 181 McManus Creek at mouth 277-280 miscellaneous measurements of 302 Mammoth Creek at Miller House 196-198 miscellaneous measurements of 212 Mammoth Creek diversion ditch 198-199 Mammoth Creek Mining Co., work of em- ployees of 13 Manley, F. G., work of 13 Marion Creek, miscellaneous measurements of 119 Mastodon Creek, miscellaneous measurements of 212 view of 63 (PI. VI) Mastodon Fork of Eagle Creek above storage dam 169-170 Midnight Sun ditch, miscellaneous measure- ments of 324 Miller Fork ditch, miscellaneous measure- ments of 180 Miller Creek at mouth 199-200, 268-269 miscellaneous measurements of 212, 270 Miller House, daily precipitation at 34 Mammoth Creek at 196-198 Mineral resources of region 18 Miner's inch, definition of 49 Minimum discharge, discussion of. 325 table showing 326 Minook Creek above Little Minook Creek. . 225-227 miscellaneous measurements of 233 342 IKDEX. Page. Minook Creek drainage basin, description of . 223-225 miscellaneous measurements of 233 stream flow in 223-233 Mission Creek above Colorado Creek 121 above Oregon Creek 120 Mission Creek drainage basin, description of. . 120 miscellaneous measurements of 131 stream flow in 120-131 Mogul Creek, miscellaneous measurements of. 154 Montana Creek at claim "No. 7 above" 102-104 Monument Creek at Chena. Hot Springs. . . 250-251 Moose Creek, miscellaneous measurements in 119, 271 Moose Creek ditch, miscellaneous measure- ments of 119 Mosquito Fork of South Fork of Fortymile River at Kechumstuk 76-78 miscellaneous measurements of 94 Murphy Creek, miscellaneous measurements of 303 N. Napoleon Creek, miscellaneous measurements of 94 Neuner, George, jr., work of 12 New York Creek at ditch intake 308-310 miscellaneous measurements of 314 Nome Creek above Ophir Creek 214-216 4 miles above Moose Creek 213-214 miscellaneous measurements of 217 Northern Commercial Co., work of employees of 13 Nugget Creek, miscellaneous measurements of 154 Nugget Gulch, miscellaneous measurements of 222 O. Ohio Creek, miscellaneous measurements of. . 322 Olympia Creek, miscellaneous measurements of 251 Ophir Creek, miscellaneous measurements of. 217 Orphan Boy Creek, miscellaneous measure- ments of 303 P. Parker, G. L., work of 12 Parsons, W. H., work of 13 Patterson Creek drainage basin, description of 323 miscellaneous measurements of 324 stream flow in 323-324 Pedro Creek, miscellaneous measurements of. 306 Pioneer Creek at What Cheer Bar ditch in- take 315-317 Poker Creek, daily precipitation at 32-33 miscellaneous measurements of 94, 303 Poker Creek ditch, miscellaneous measure- ments of 303 Pool Creek at mouth 294 Porcupine Creek above ditch intake 182-184 below Bonanza Creek 185-188 below ditch intake 184-185 Porcupine ditch at intake 205-206 Portage Creek 4 miles above Medicine Lake. 204-205 Preacher Creek, miscellaneous measurements of 181 Porter, E. A., work of Precipitation, daily, at Charity Creek. at Chicken Creek. at Cleary at Crooked Creek at Discovery Fork Page. 13 34 35 33 36 37 at Eagle 25-28 at Fairbanks , 28-31 at Faith Creek 33 at Miller House 34 at Poker Creek 32-33 at Summit Roadhouse 33 Precipitation in region 23-24, 337 Precipitation, monthly, at stations in British Columbia and Yukon Territory.. 38 at stations in Yukon-Tanana region... 37-38 mean, at stations in Yukon-Tanana region and Yukon Territory 39 Precipitation stations in Yukon-Tanana re- gion 24 in Yukon Territory and British Columbia 24 Principal rivers of North America, length and drainage area of 60 Ptarmigan Creek, miscellaneous measure- ments of 180 Publications, list of 14-16 method of obtaining 13-14 Q. Q,u.al Creek at claim "No. 7 above" 219-220 at claim "No. 9 below" 221-222 miscellaneous measurements of 222 South Fork of, miscellaneous measure- ments of 222 view of 218 (PI. VH) Quartz Creek, miscellaneous measurements of 105, 212, 324 R. Rainfall, annual, fluctuation of, at Alaska stations 40 Rampart, Yukon River at 66-67 Rampart quadrangle, reconnaissance map of In pocket (PI. XIII) Rock Creek, miscellaneous measurements of. . 154 Ruby Creek, miscellaneous measurements of. 233 Run-off, definition of 49 Russian Creek, description of 233 S. Salcha River at mouth 238-240 Salcha River drainage basin, description of. . 238 stream flow in 238-243 Scope of report 336 Second-foot, definition of 49 Seventymile River above Flume Creek 132-134 at the falls 134-137 miscellaneous measurements of 154 North Fork of, estimated discharge and horsepower for 332 Seventymile River drainage basin, descrip- tion of 131-132 miscellaneous measurements of 154 stream flow in 131-154 Shaw, T. ,T., work of 13 Sheep Creek, at mouth 176-178 Slate Creek, miscellaneous measurements of 105,233 Sluice head, definition of 49 INDEX. 343 Page. Smith Creek above Pool Creek 292-293 miscellaneous measurements of 119. 302 Solo Creek, miscellaneous measurements of. . 270 Sonickson Creek above ditch intake 145-147 Sonickson Creek ditch, miscellaneous meas- urements of 154 Sorrels Creek above Elliott Creek 257-258 miscellaneous measurements of 270 Sourdough Creek, miscellaneous measure- ments of 303 Squaw Creek, description of 233 Squaw Gulch at claim "No. 1 above" 116-119 Starvation Creek, miscellaneous measure- ments of 271 Steel Creek, at mouth 111-113 Fortymile River at 73-76 Fortymile River below, view of 62 (PI. V) Stream flow, field methods of measuring 50-53 oflice methods of measuring 53-54 Sullivan Creek above Tofty ditch intake... 323-324 Summit Roadhouse, daily precipitation at. . . 33 Switch Creek, miscellaneous measurements of 212 T. Tables, explanation of 54-56 Tanana River at McCartys 234 below Chena 234-235 Tanana River drainage basin, description of 233-234 miscellaneous measurements of 237 stream flow in 233-237 Temperature, monthly, at Eagle 19 at Fairbanks 1^20 Temperature of region 19-22, 337 Terms, definition of 49 Thanksgiving ditch near outlet 311-313 California Branch of, near intake 313-314 miscellaneous measurements of 314 Thorns, A. V., work of 13 Tolovana River drainage basin, description of 270 stream flow in 270-303 West Fork of, miscellaneous measure- ments of 271 Topography of region 336 Trail Creek, miscellaneous measurements of. . 217 Transportation, means of 43-44 Troublesome Creek below Quail Creek 218-219 miscellaneous measurements of 222 view of 218 (PI. VII) Twelvemile Creek, miscellaneous measure- ments of 180 North Fork of, miscellaneous measure- ments of 180 U. United States pumping plant, American Creek at 125 V. Page. Vegetation of region 41-43, 337 W. Wade Creek at claim " No. 10 above " 85-88 miscellaneous measurements of 94 Walker Fork above Cherry Creek 83-84 above Poker Creek 82-83 above Twelvemile Creek 84r-8o miscellaneous measureijients of 94 Washington Creek above Aggie Creek 272-273 above dam 147-148 below Aggie Creek 273-274 Washington Creek ditch, miscellaneous measurements of 154 Washington Creek drainage basin, descrip- tion of 154-15.5,272 stream flow in 272-275 Water power, general conditions of 326-328, 338 Water-power plants, sites suitable for 328-332 Water supply, conditions of 45-48, 337-338 during winter 46-48 effect of topography on 46 seasonable distribution of 45 WTiat Cheer Bar ditch, miscellaneous meas- urements of 318 What Cheer Bar ditch near intake 317-318 Whitehorse, Yukon Territory, Fiftymile River at 67 Vv'obber, Herman, work of 13 Wolf Creek above Swanson's dam 121-122 miscellaneous measurements of 181, 303 Wolverine Creek, miscellaneous measure- ments of 314 Woodchopper Creek, miscellaneous measure- ments of 324 Woods Creek, miscellaneous measurements of 119 Y. Yukon River at Eagle 62-66 view of 62 (PI. V) at Rampart 66-67 di ainage areas of 61 Yukon River drainage basin, description of. . 60-62 stream flow in 60-67 Yukon-Tanana region, distribution of timber in, map showing 40 (PI. II) location of, map showing 16 (PL I) monthly precipitation in 37-38 precipitation stations in 24 Yukon Territory and British Columbia, mean monthly precipitation at stations in 39 precipitation stations in 24 Z. Zug, John, work of 13 O LEAg I J U. S. GEOLOGICAL SI GEORGE OTIS SMITH. D^ER 342 PLATE X 41001 :^— 165 GO' 142 00' Trian^ulation and topo^r Surveyed in li Corrections for geodetic and for topo^ra phy alo international boundary; I909-I9II, bythe Alaska I 64°00' 141 00' LEGEND Rainfall station ; letter refers ijto list in text, Gaging station ; number refers to list in text RECONNAIS, ALASKA 1 !;C lii ■1^ # . refers CO I. RECONNAISSANCE MAP OF THE FOiTYMILE QUADRANGLE, ALASKA SHOWING LOCATION OF RAINFALL AND OAGING STATIONS LbAg'i'j f ■ I ' III J^-Lg BBB I \ WATER-SUPPLY PAPER 342 PLATE XI RECONNAISSANCE MAP OF THE CIRCLE QUADRANGLE, ALASKA SHOWING LOCATION OK RAINFALL AND GAGING STATIONS I B Ol.ver. J V i Gerdir ^'i/' iJH .■^. LEAg- 111 \ WATER-SUPPLY PAPER 312 PLATEXIl ! i i 5 1 I SUT'/-^ ... . ^^r^ '- :>, r^'K "p ^'^ f! if^'f s^^^^-^-i=g^V^ i'^'>tfT^^ vi t '^lU RECONNAISSANCE MAP OF THE FAIEBANKS QUADRANGLE, ALASKA SHO'i^TNG LOCATION OF RAIHTAM. AND GAQIN9«rATI0NS O Gaging station; number refenIA LBAgt^ 1 mmmm { HmfmHifa'LP^ CONGRESS 019 953 822 6 f!:i|!i'';iii; I, .; ,1(1 i.u. .i.L ^mmmt- mi % ^:!iil •rn: ')()(; ■u;;-. -'^ii >y;::'n\.i::J' mi \'Mu>''±wm ;:|;il)l; H;';i;t;!.|!i^!lJl ifl) K:;