GB DEPARTMENT OF THE INTERIOR Franklin K. Lane, Secretary United States Geological Survey George Otis Smith, Director WATER-SUPPLY Paper 426 SOUTHERN CALIFORNIA FLOODS OF JANUARY, 1916 BY H. D. MoGLASHAN and F. C. EBERT Prepared in cooperation with tlie STATE OP CAUFORNU WASHINGTON GOVERNMENT PRINTING OFFICE 1918 Class jiJi^j^L^. //. DEPARTMENT OF THE INTERIOR Franklin K. Lane, Secretary United States Geological Survey George Otis Smith, Director Water-Supply Paper 426 SOUTHERN CALIFORNIA FLOODS OF JANUARY, 1916 j^^ BY H. D. McGLASHAN AND F. C. EBERT Prepared in cooperation with the STATE OF CALIFORNIA WASHINGTON QOVERNMEXT PRINTING OFFICE 1918 -^ of ADDITIONAL COPIES OF THIS PUBLICATION MAY BE PROCURED FROM THE SUPERIXTEXDEXT OF DOCUMENTS GOVERNMENT PRINTING OFFICE WASHINGTON, D. C. AT 15 CENTS PER COPY P. Of ©• APR 30 1918 CONTENTS. Page. Introduction 7 Acknowledgments - 8 Precipitation 10 Storms of January, 1916 10 Rainfall in earlier years 17 Intensity and distribution of rainfall 20 Flood of January, 1916 22 Crest discharge 22 Condition of reservoirs during flood 24 Morena reservoir 1 24 Lower Otay reservoir 25 Sweetwater reservoir 26 Cuyamaca reservoir 26 Damage due to flood 27 Loss of life 27 Agricultural lands 28 Municipal property 28 Water supply 29 Power plants 30 Railroads 31 Highways and bridges '. 32 Telegraph and telephone lines 33 Miscellaneous damages 34 Comparison of flood of 1916 with previous floods in southern California 35 Basis of comparison 35 Tia Juana River 36 Sweetwater River. , : 36 San Diego River 37 San Luis Rey River 38 Temecula Creek 39 Los Angeles and San Gabriel rivers 40 Flood run-off in January, 1916 40 Collection of records 40 Tia Juana River basin 41 General features 41 Cottonwood Creek at Morena reservoir, Cal 42 Otay River basin 43 General features 43 Otay River at Lower Otay reservoir, near Otay, Cal 44 Jamul Creek near Otay, Cal 45 Sweetwater River basin 45 General features 45 Sweetwater River near Descanso, Cal 46 Sweetwater River near Dehesa, Cal 47 Sweetwater River at Rudolph ranch, near Dehesa, Cal 47 Sweetwater River near Jamarho, Cal 48 Sweetwater River at Sweetwater dam, Cal 48 3 4 CONTENTS. Flood run-off in January, 1916 — Continued. Pa„g San Diego River basin 49 General features 49 San Diego River at diverting dam near Lakeside, Cal 50 San Diego River at Capitan Grande dam site, near Lakeside, Cal 52 San Diego River near Santee, Cal 52 San Diego River at San Diego, Cal 53 Boulder Creek at Cuyamaca reservoir, near Julian, Cal 54 San Vicente Creek at Foster, Cal 55 Switzer Canyon at San Diego, Cal ■ 55 San Diegiiito River basin 5g General features 56 Santa Ysabel Creek near Mesa Grande, Cal 56 Santa Ysabel Creek near Ramona, Cal 57 San Diegiiito River near Bernardo, Cal 58 Santa Maria Creek near Ramona, Cal 59 San Luis Rey River basin 61 General features 61 San Luis Rey River near Mesa Grande, Cal 61 San Luis Rey River near Nellie, Cal 62 San Luis Rey River near Pala, Cal 63 San Luis Rey River at Pala, Cal 64 San Luis Rey River at Bonsall, Cal 64 San Luis Rey River at Oceanside, Cal 65 Moosa Canyon Creek near Bonsall, Cal 66 Santa Ana River basin 67 General features 67 Santa Ana River near Mentone, Cal 68 Santa Ana River at San Bernardino, Cal 68 Lytle Creek at San Bernardino, Cal 69 San Jacinto River near San Jacinto, Cal 70 San Jacinto River near Elsinore, Cal 70 History of Elsinore Lake 71 Elsinore Lake at Elsinore, Cal 72 South Fork of San Jacinto River at Hemet reservoir, near San Jacinto, Cal 72 San Gabriel River baain 73 General features 73 San Gabriel River near Azusa, Cal 74 Los Angeles River basin 75 General features 75 Los Angeles River at Los Angeles, Cal 75 Arroyo Seco near Pasadena, Cal 76 Arroyo Seco at Los Angeles, Cal 77 Santa Clara River basin 77 General features 77 Sespe Creek near Sespe, Cal 77 Index 79 ILLUSTRATIONS. Page. Plate I. Map showing precipitation and gaging stations in San Diego, Orange, Riverside, San Bernardino, and Los Angeles counties In pocket. II. A, View up Lower Otay reservoir after failure of dam; 5, View down- stream at site of Lower Otay dam, after failure 24 III. A, Sweetwater dam after flood of January, 1916; B, Break at right end of Sweetwater dam after flood of January, 1916 25 IV. A, View up Mission Valley, San Luis Rey River, in 1915; B, View up Mission Valley, San Luis Rey River, February 21, 1916 28 V. A, View across Mission Valley, San Luis Rey River, at D. Jones's ranch after flood of January, 1916; B, View up San Luis Rey River at junction with Moosa Canyon Creek after flood of January, 1916. . 29 VI. A, Winston ranch, Mission. Valley, San Luis Rey River, February 21, 1916; B, Canfield ranch, near Bonsall, San Luis Rey River, February 21, 1916 30 VII. A, San Diego River at San Diego after flood of January, 1916, show- ing damage to county and Atchison, Topeka & Santa Fe Railway bridges; B, Santa Margarita River near mouth after flood of Janu- ary, 1916, showing damage to State highway and Atchison, Topeka & Santa Fe Railway bridges 31 VIII. A, View up San Luis Rey River from mouth after flood of January, 1916, showing damage to Atchison, Topeka & Santa Fe Railway and State highway bridges; B, Debris on beach at Oceanside and delta built up by San Luis Rey River after flood of January, 1916 . . 32 IX, A, Highway bridge across San Luis Rey River at Pala before flood of January, 1916; B, Wreck of highway bridge across San Luis Rey River at Pala after flood of January, 1916 33 X. A, View downstream on Sweetwater River near Descanso after flood of January, 1916; B, View upstream on Jamul Creek near Otay after flood of January, 1916 46 XI. A, View upstream showing Capitan Grande dam site on San Diego River after flood of January, 1916; B, View upstream on San Vicente Creek at Foster after flood of January, 1916 47 XII, A, View up San Diego River at Mission dam, nearSantee, after flood of January, 1916; B, View up Mission Valley, San Diego River, from old municipal pumping plant, after flood of January, 1916. . 52 XIII. View up channel of San Diego River at Lakeside after flood of Jan- uary, 1916 53 XIV. A, View upstream on Santa Ysabel Creek near Mesa Grande after flood of January, 1916; B, View across Santa Ysabel Creek near Ramona after flood of January, 1916 58 XV. A, View downstream at Carroll dam site, on San Dieguito River near Bernardo after flood of January, 1916; B, View downstream on Santa Maria Creek near Ramona in 1917 59 XVI. A, Gaging station on Santa Ana River near Mentone after flood of January, 1916; B, View across channel of San Gabriel River at mouth of canyon near Azusa after flood of January, 1916 68 XVII. A, View upstream on San Jacinto River near Elsinore after flood of January, 1916; B, View eastward along north shore of Elsinore Lake, March 10, 1916 69 6 SOUTHEEX CALIFORNIA FLOODS OF JAJsUARY, 1916. By H. D. McGlashax and F. C. Ebert. INTRODUCTIOX. The rains that swept southern Cahfomia in mid-January, 1916, converted the streams into torrents that overran their banks and devastated wide areas of the most fertile land of the State. The rains were heaviest and the floods most disastrous in San Diego County, but they were also very heavy in parts of Riverside, San Bernardino, Los Angeles, and Ventura counties, and they "^Tought widespread ruin throughout the region that extends southward from Santa Clara River to the Mexican boundary, and westward from the north-south ranges of San Bernardino and San Diego counties to the ocean. For nearly a month San Diego County was practically cut off from communication with the rest of the State. Fortunately the wireless could be used even after all telegraph and telephone hues failed, and suppHes urgently needed at San Diego were brought in by steamer. Aside from the loss of life, the most serious loss was that resultmg from the destruction of the results of the work of generations on well-developed farm lands and their improvements. Dams that are broken down, bridges that are washed out, water mains, pipe lines, irrigation ditches, wells and pumps, and power plants that are damaged can be speedily repaired if funds are available, but it requires a long time to efface completely the track of a flood in a fertile, intensively cultivated river valley. A record of the magnitude of such a flood and a study of the damage done and of the history of previous floods are of value not only in efforts to solve the general problem of flood prevention, but also in planning the complete utilization of the water resources of a region. In San Diego County, especially, where the losses were very heavy, a number of feasible reservoir sites have not been developed because the expense is apparently not yet warranted by the demand for their utihzation for water supply alone. A detailed study may show, how- ever, that the value of these sites as reservoirs for flood protection is sufficient to justify the county in assuming part of the cost of con- 7 8 SOUTHERN CALIFORNIA FLOODS OF JANUARY, 1916. struction or assessing it against the properties to be protected. A fundamental requirement for this study is a knowledge of precipita- tion and stream flow, such as that presented in the records given in the following pages. The records of precipitation have been collected by the United States Weather Bureau and many private parties at 156 stations fairly well distributed throughout the area. The records of stream flow have been collected by the United States Geological Survey and coop- erating parties, and these also include many records furnished by private individuals. The importance of these records to engineers who are charged with the duty of designing and building structures along these streams is obvious and is impressively emphasized by the magnitude of the floods studied and the enormous destruction they have wrought. The engineer will be impressed with the fact that whereas damages to property resulting from failure of engineering structures may be evaluated as a basis for determining the limit of economic cost of such structures, the loss of life can not be evaduated. Structures whose safety involves human life should, therefore, be designed much more securely than those whose failure would involve damage to property only. ACKNOWLEDGMENTS. It is a distinct pleasure to acknowledge the cordial assistance ren- dered the writers by engineers, public officials, officers of various com- panies, and all others of whom such assistance was requested. All stream-gaging work of the United States Geological Survey in California is done in cooperation with the State Department of Engineering, W. F. McClure, State engineer, and the State Water Commission, W. A. Johnstone (president) , Irving Martin, and A. E. Chandler, commissioners. The section of the report relating to flood run-off would have been much less complete and accurate if it had lacked the data and assist- ance furnished by Mr. W. S. Post, consulting engineer for theVolcan Land & Water Co. and the Cuyamaca Water Co. During the floods and in the weeks following these companies made a very strong effort to col- lect aU information possible, and they also placed special parties in the field at different times to obtain such additional data as the writers desired to complete and check parts of the records. The chief engineer of the Sweetwater Water Co., Mr. John F. Covert, furnished a number of valuable flood records which he had carefully collected, and Messrs. G. S. Strout, E. R. Bowen, and C. H. Lee obtained stream measure- ments and furnished very helpful information regarding the floods on the San Luis Rey. The list would be long if mention were made of ACKNOWLEDGMENTS. 9 all parties who cooperated. Specific acknowledgment is made in con- nection with the detailed records. All pubUshed and unpubhshed records of the United States Weather Bureau in the area covered by this report were furnished through Mr. G. H. Willson, section director, San Francisco. The local offices at Los Angeles and San Diego also furnished much detailed information. Records collected by private parties are acknowl- edged in connection with data for the stations. The Los Angeles County records were furnished by Mr. J. W. Regan, engineer of the flood-control district. Estimates of the amount of damage to property were furnished as follows : Assessors: Montgomery M. Moulton, San Diego County; James Sleeper, Orange County; C. B. Bayley, Riverside County; E. J. Gilbert, San Bernardino County; Ed W. Hopkins, Los Angeles County. County engineers and surveyors: George Butler, San Diego County; J. L. McBride, Orange County; A. C. Fulmor, Riverside County; J. A. Sourwine, San Bernardino County; and F. H. Joyner, Los Angeles County, road commissioner. City engineers: George Cromwell, San Diego; J. M. Oakey, San Bernardino; Clarence E. Bayley, Pomona; R. V. Orbison, Pasadena; Homer Hamlin, Los Angeles; Albert de Ruiz, Long Beach; and Chas. E. Chambers, president board of trustees, San Jacinto. Railway engineers: A. Ervast, chief engineer, San Diego & South Eastern Rail- way Co., San Diego Electric Railway Co.;'E. J. Kallright, general superintendent, San Diego & Arizona Railway Co.; W. J. Gough, superintendent, Los Angeles & San Diego Beach Railway Co. ; J. McMillan, general manager, Pacific Electric Rail- way Co. ; Arthur Maguire, chief engineer, San Pedro, Los Angeles & Salt Lake Rail- road Co.; J. Q. Barlow, assistant chief engineer, Southern Pacific Co.; R. B. Ball, engineer Grand Division, Atcheson, Topeka and Santa Fe Railway Co. Water company engineers: John F. Covert, chief engineer, Sweetwater Water Co.; F. M. Faude, assistant manager, Cuyamaca Water Co.; J. B. Dixon, superintendent, Escondido Mutual Water Co.; Francis Cuttle, president. Riverside Water Co.; W. S. Post, consulting engineer. Lake Hemet Water Co.; H. R. Case, manager, Temescal Water Co. Miscellaneous: F. H. ToUe, secretary and general manager, South Coast Land Co.; R. C. Starr, hydraulic engineer, Pacific Light & Power Corporation; H. W. Dennis, construction engineer, Southern California Edison Co.; C. O. Poole, chief engineer, Southern Sierras Power Co.; Austin B. Fletcher, State highway engineer; J. L. Ord, division plant superintendent. Western Union Telegraph Co.; C. L. Lewis, super- intendent. Postal Telegraph-Cable Co.; D. P. Fullerton, general superintendent of plant. Pacific Telephone and Telegraph Co.; L. M. Klauber, superintendent electric department, San Diego Consolidated Gas & Electric Co.; L. M. Drown, manager, Western Salt Co.; T. L. Barnes, general manager, Fentou-Sumption-Barnes Co.; C. R. Olberg, U. S. Indian Office; Maj. G. B. Pillsbury, Corps of Engineers, U.S. Army. The loss of life was reported by the following coroners: Dr. Otto G. Marsh, San Diego County; Theo. A. Wmbigler, Orange Coimty; C. S. Dickson, M. D., Riverside County; J. L. McMinn, San Bernardino County; and the coroner's office of Los Angeles County. 10 SOUTHERN CALIFORNIA FLOODS OF JANUARY, 1916. PRECIPITATION. STORMS OF JANUARY, 1916. The storms from wliich the floods of January, 1916, resulted began January 17, but light rains had been reported for several days preceding. The United States Weather Bureau ^ described the storms as follows : It seems reasonable to suppose that the storm which swept over Hawaii on the 18th- 19th passed inland over California on the 27th. It is charted as Low No. XIV, Chart III. About a week previous Low No. X, Chart III, passed inland over the middle California coast on the 17th, crossed the south-central part of the State on the ISth, and then moved northeastward into Wyoming by the morning of the 19th. DuriBg its movement over the south-central portion of CaHfomia the storm slackened its progressive movement, meanwhile giving very heavy rains over the coimties of southern California. Light rains had fallen during the previous three or four days and conditions were unusually favorable for a high run-off in connection with the heavy rains of the 17th and 18th. * * * The resulting floods were severe and much damage was done to railroads, bridges, highways, land under cultivation, and to the harbor of Los Angeles, by reason of the mass of silt deposited thereon. A second deluge of rain descended upon the counties of southern California in connection with Low Xo. XIV, mentioned in a preceding paragraph. The second storm was of much shorter duration. At San Diego, Cal., the rain began at 7.18 p. m. of the 26th and ended at 7.45 p. m. on the 27th. The total fall amounted to 2.41 inches. This rainstorm was attended by imusually high winds for southern Cali- fornia, the average velocity at San Diego being about 30 miles per hour, with a maxi- mum of 54 miles from the south at 4.29 a. m. of the 27th. The reservoirs in the county whence the water supply of the city of San Diego is drawn were already nearly full as a result of the rains of the previous week, and all of them, evidently, were not in a condition to withstand the added strain put upon them by the rains of the 26th-27th. The table on pages 12-16 contains records of precipitation not only at stations maintamed by the Weather Bureau, but at many other stations maintained pubhcly or privately in the basins described in this paper. A few records obtained in adjoining river basins have been added for pui'poses of comparison and indicate the limits of excessive precipitation during the two storms. (See PL I, in pocket.) From the records presented in these tables the mean precipitation for the principal drainage basins in San Diego Coimty has been computed for the period covered by the storms. Kecords for these basins were collected at 63 stations fairly well distributed throughout the region. The stations were plotted on the mtip (PI. I), and lines of equal precipitation were drawn. The boimdary of each drainage basin above selected points was also indicated, and the areas between adjacent precipitation lines within each basin, were measured with a planimeter. The results are given in the following table: 1 MonthJy Weather Review, vol. 44, No. 1, January, 1916. PRECIPITATION. 11 Mean precipitation in drainage basins in San Diego County, Cal.,for period Jan. 1. 30, 1916. to Station. Drainage area. Mean precipi- tation. Otay River at Lower Otay dam Jamul Creek above Lower Otay reservoir. Sweetwater River at Descanso Sweetwater River at Sweetwater dam San Diego River at diverting dam San Diego River at Lakeside San Diego River at Mission dam San Diego River at San Diego San Vicente Creek Santa Ysabel Creek near Mesa Grande Santa Ysabel Creek near Ramona San Dieguito River at Carroll dam site. . . San Diegiiito River at mouth Santa Maria Creek near Ramona San Luis Rev River near Mesa Grande. . . San Luis Rey River near Nellie San Luis Rey River near Pala San Luis Rey River at Bonsall San Luis Rey River at Oceanside Square miles. 98.6 69.8 43.7 181 102 203 375 434 74.9 53.4 110 299 a 340 57.3 209 240 322 46.5 565 Inches. 19.2 21.0 27.4 21.8 27.6 25.0 21.4 19.9 19.2 30.3 25.8 23.6 22.4 21.2 24.9 25.4 25.7 24.3 22.6 a Approximate. In the mountainous part of the area much of the precipitation was in the form of snow, as shown by the following table, in which the amount of snow on the ground on January 15 is compared with that remaining January 3 1 : Snowfall, in inches, in mountains of southern California for January, 1916. a Station. Total snow- fall. Amount on ground on 15th. Amount on ground on 31st. Com- pared with normal. Bear Valley dam. Converse Nursery Holcomb Squirrel Inn Seven Oaks Nellie Julian 30 +59 +32 + 22 a Willson, G. H., Climatologicaldata, California section, January, 1916, p. 11. 12 SOUTHERN CALIFORNIA FLOODS OF JANUARY, 1916. -3 5 •2^^ 6 6 6^ ^5 a oQpca I I S t. 3 b S Im o^a© pq ^ c3 t- c3 (3 03 cS o . . o U o ® ® s^ ^-^« us CO(M «3 OOO KNt-h (MC>^ iCCOrHCO CD CO i-H CO «0 ^ 1-1 ecOT-ir-; (N C^ CO t> - r-i Jo § § (N I-H CO S s § Csj ""J" 00 ^ 2.00 20.0 3.26 r^ lO -^ 00 00 Oi0 O "0 :eh S8§S? w^. "(NCO 8SS8 S2S8SS 8gS?^SSSSS228S; C000O-<*< OOrtCO'Oi-HCO t^t^ocooo-^«o«>c^-^«5t>.toi th coco-* CI ■»*<■* S§8 r^ocosO'— icsco-<» o a o o o^ d t3> p ^5 es73 oooooocooo QQGCOQQQQQ ?5S;2! lO 00 t^ oo o o >S •<*• •^ S cst^ 8 2§J^S ?5§^^ 2?3 l^SS « S^'£^ 2S SS^^S ) i~ lO -^ M t- w >-o o ■^ -^ a5 ^■22:^ ^ S'^^i^ ^2 gc5^J:;S 2S ;=2SSS?S22S3*S 9 : : : g S i i^ § §S Sgg ^ ^c^J ^ o> s^ 2 gs?§ « J§ •s « '- ^^g ^ __ ^., —, s; *_ — ?^ '^ ^ : eso c<5c» o s § iSooSSt • O •iO-<*'-C O CO lOOOO 03t- uo -H c4 -<■ 05 COOO OSSCi— t^ooo-^ooio N2-n52- 00 lO CO "5 8S ore 00 C5X o COOCfN s s^ C<1 r^ SSSS ; ;g25:;2. OQ15Q O 00< T»< Q lO C5 O 00 O < •^00'45 O5O50C! 50 r^or., Ol CO CO CO CO ^:$ 5oo«o o uoo^ ro i-o CO t^ o >o S o to o ®!22SC) 'Sri QQOt^ooo-^QO'Ooo -H05OC3-H 00 '-'3 >ooo--ioo-H25o^ir50 r^oOOTOoc cst^ i-HOt^ ro.>c oc !>• o o o t~- 25 cNreOi-OifliCiO OCO OOOOOOOWO( o b E a 3 : o • A : 'So?:; ° 5.0 X5XS S ©X: C /;C3C3 C3c3>^'>. -iC3 •Si •§ :ii Wj^d © C3 O c3 ©©03 ica .^^ dsS© c~ Oft ftWCh.; S a??iCAH M> B O O •-< 3 • • ftS2Mx^^>rf -X! M -^ I § e DO o a • C © ,- O rt 14 SOUTHERN CALIFORNIA FLOODS OF JANUARY, 1916. OS o 1 O O 0*J CQQ| « 0^5550 o°° oooo " ci^ ® o ° 6 d d o d^ c c 6 o o o a 'oSSesiSi sss< C£ OS t^ 005 Tf m o CO oc o 1 ':5S2S;:S S«»«»2 ^2^?S 22< ooiiniN •s •3 "2 ■<*^Meoao e^oxNoC5co05cci^-«» 00 CO CO 25 ^ CO »' O O oi p 30 CO OJ 00 O CO CO aO t>^ 06 O ei Co' -O 05 nc>S CO -H ,-i^H-H>H I -H CO -H es s^ ! SSJ o . 0>C lOC^ ■ I^S::: :S o» . COiO ^g???^^ igS^jJgSS g :§S :8£;S 0000 00 CO- Tf Olds t-- oj i CO Csj .-H CO ci O -^ O -< CO CO CO i-H -^ CO C^ •^ f^ O-^-^O ©OCN ■«*ac^'r-^(N>o-^foe^^cdco-H t>:,^^eo co-h^ (N»OiOO C50C-';(N co^r^oooco d loescoo— «-H xcoo— ■ — ot^-^ es -H cs ^ cs CO CO c CO "3 coe* eoc^-^eo coiocouo eoc>flO cnm-vei I -^ o j# -^ t^ot^uot-irj-ccooxcooo -*oe<)c^» ^^^OLOOcsix — i-eocc-i e*< M CO ■* ■«*< «o ■<*<-«fcoco PRECIPITATION. 15 2 533 33.53 03 g >>o >.g >;§>. g >>g >'2 >.g ^g C *jfc;*ju wt.*j ui -ju r:t- -^5 OH = S5 S= =53 5 §= §= 3| ll ^ S- 5- 5-§ - 0- PZ 0% £? 5 w© ^a, ^owi o ^o ^o -'2 5 ji -aJS gJ3 g-^g -3 '^--^ o-^ ©5 j-^ 1 fi 1= l^l » 1^ 1^ 1« "Sl 8^. 8=°. S'^S ^. 8°^ 8"^ 8"^ 8^ D ^::i ^D j:dj ;d ^d ^d ^d m:^ ?i »M — < ?» -H -^ -H -< . ^ — < 55 _< ;s) _< ^ ^ ^ « _ _H -H -H ,-< ,.- -< ^ ,^ ^ ^ ^7^ C4.^ e>»CM:£OXL-;— I— < t^ o acssQ'-'^c:— 'Xtcsssix?^ — Oor^Q cc ?^ f cc X r^ r- 3; oc ^ C S z! S '-2 ^ tCiCL-iooJsJ^'-' ■-:^ ».';x'ci^c-r^c^^^^C3ds5^^d■-'^o-'oj oco-< o6---fl<)XrC:=C!35rre>» (N-0 : : :3B •-': o : — t^ -^ - :^r-:c>« c>» fC i.-S X LI ».-: s: n L-t r>. c ~ o X i--^ .c 1- r- o ifl o o c -.s ^ re •.~ ^ o >.-; cs = c= x !N o ox — —" C5-^Oi "--:;» '-'' — X cc^ — o x co c^JO'-^t^ o "65 .58 3.35 .07 .41 oo :-o^°"== ?2 : : ^^ ;§ ;re ' ro O -^ --—<—< O • 'S' re o> O 1 § :3S NO :^ •?^ -SS; -- -r X c-3 u-? r^ i.'^ o o o o o p O O O O O I- :-: O O u.- 1- o •-" o »?>) — •-•ror^ ot^?5rroo>-orjoot~r^MO~-^ ;2 gSgSo 8 ? B » » t- 2ggS: xS?o — MC^t^ro .~: "T •« « r^ X 10 >0>0>OtO>Q lOtOOUJO «0 «0 >0 10 «0 to lO «0 «0 U5 «a 10 10 »0 U5 u1 1.-^ ■ ■-: ■.ei.'SiCo-a | — ® OS ! S^ O^ ?^ li ^ up « s © 5 H — . ~ t: •<* «« . as a :s^ 5 = o cso M - C - ■ S5* -I = ^ •=•=_ — ^ C > S = w X s 53 9 O TO > ;j3 ; - w ■;r = ^ -. j=? ° r= £ ="3 16 SOUTHERN CALIFORNIA FLOODS OF JANUARY, 1916. I fe 3 ■»^ eS C8 o ^ 5 lA ^ ? o S3 11 ■»J 3 »-; t3 o — X3 c3 . -1^ "^ cc oog {^5 d ^ a hi § s 5S "^ H §, ! (N o i cc ^ E- R ^ I oe o (N oc t^ lO (N §. ^ «o oi 1 ^- CM s ^ : CO -M C5 ^ 1 o c>^ OC' t~- ,-1 '-^ t^ t^ r- ^ <^^ g o 1 ; g ,- 1 : '"' ! ; ac •^ o ^ 6 ii^ ! 1 1 s-^J CO ^ ISs:^ S S 3 .a _5 fl 6 m il 1 •-; <» fc. Sfe ^ O) b O o S S « 2s Ii 3 2 3 CO o ia^il m t^ 2 © C3 rj >» p ^ t2 o o a3 ©^ o« " o^ S O 3 o d =! i=i fc-r) _L o 3 © 'S.2g^©S fc a "^^ ^"s g o ©-^ £ M fc-S c3 >:; Ch:j s2 d 5 — ^ T •J||.|S| +^?5 g ©^ ^ ^5; ° S & a . c-2 " c u ^ I2i-ae •^ c i; a pips g^8^2S ai3s::-2 +^ p =5-^^ -. T|s©IS o^-©g-c;r •§a^3g PRECIPITATION. 17 RAINFALL IN EARLIER YEARS. In order that the records of precipitation for January, 1916, may be compared with those of preceding years, complete monthly records of ranifall at San Diego, Los Angeles, and Santa Barbara are given in the following tables. The precipitation for January, 1916, was the maximum for that month recorded at these stations. It was, how- ever, exceeded by the precipitation in February, 1884, at Los Angeles and San Diego, and by that of March, 1867, at San Diego. At Santa Barbara the rainfall of January, 1916, exceeded that of the next highest month, December, 1867, by 36 per cent. See table on page 20. Precipitation, in inches, at San Diego, Cal., 1850-1916. 1 < i 1 1 O 1 > o 'A 1 1 1 1 i < l-s 1 i 1 < 1850 0.03 1.13 1.51 1.00 .34 0.09 .87 0.71 0.68 .01 "8.'4i 1850 7.84 1850-51... ■"'6' ""o ....„ ' o.'ig '■2.'82 "i'93 1851 i 7.49 1851-52... 0.02 .01 .25 3.74 .58 1.84 1.87 .86 .32 9.48 1852 11.87 1852-53... 0.40 .06 1.45 4.50 .60 .20 1.52 .25 2.10 .05 11.03 1853 7.88 1853-54... .21 1.28 1.77 .99 2.56 1.88 .89 .18 .01 9.77 1854 11.63 1854-55... 0.07 1.36 .09 .27 .04 3.29 1.97 3.59 1.30 1.52 .06 13.56 1855 11.15 1855-56... .04 .11 2.15 .41 1.27 1.86 1.59 2.17 .29 9.89 1856 9.77 1856-57... .07 1.22 1.30 .26 1.76 .04 0.08 .03 4.76 1857 6. 15 1857-58... .02 .01 .49 2.16 1.30 1.52 .44 1.24 .17 .19 7.64 1858, 7.55 1858-59... .04 .10 .47 .28 3.10 1.89 .20 .36 .17 6.61 1859 6.10 1859-60... .02 .18 1.49 1.79 .72 1.49 .15 .65 .04 .06 6.58 1860 9.11 1860-61... .14 2.88 2.99 .82 .79 .05 .04 .19 7.901861 7.92 1861-62... 1.69 .05 1.19 3.20 6.56 1.39 .97 .106 .16 .48 15.64 1862 11.59 1862-63... .11 .89 .05 .93 .32 1.09 .33 .13 .02 3. 87 1863 3. 02 1863-64... .36 .73 .04 .04 2.50 .20 .01 1.26 .01 5.14 1864 7.61 1864-65... .11 .04 2.41 1.04 1.28 3.00 .66 .01 8. 45! 1865 7.52 1965-66... 1.29 .02 .52 .84 5.06 3.43 1.47 .11 .09 12.82il866 12.31 1866-67... .10 .24 1.82 2.32 .85 7.88 .48 .04 13.7311867 15.72 1867-68... .30 .34 .45 3.06 3.37 1.6:3 .73 1.20 .15 11.23 1868 11.16 1868-69... .51 .05 2.00 1.52 2.88 1.88 1.98 .53 .33 11.681869 10.96 1869-70... .05 .05 2.32 .94 .64 .77 .33 .20 .28 5. 48 1870 4.37 1870-71... .04 .07 1.54 .18 .42 .62 1.35 .01 .70 .34 5.1711871 5.64 1871-72... 1.33 1.39 .99 1.63 .46 .26 .12 7. 18^1872 5.07 1872-73... .18 1.43 .44 4.21 .11 .10 .03 6.50 1873 13.07 1873-74... 1.95 .77 5.46 3.11 3.73 1.20 .34 .32 16.88 1874 10.91 1874-75... .12 .13 .53 .88 .55 2.38 .37 .45 .12 .20 .02 5.73 1875 6.80 1876-76... .21 .39 2.25 .41 2.47 2.44 1.78 .06 .05 .05 10.11 1876 7.24 1876-77... .03 .06 .03 .08 .04 .15 1.06 .18 1.44 .26 .43 Tr. 3.75 1877 8.12 1877-78... .81 .06 3.89 1.46 4.83 1.41 2.91 .68 .16 16.10 1878 13.87 1878-79... .96 1.57 3.64 1.04 .10 .60 Tr. .07 7.88 1879 14.71 1879-80... .29 2.77 6.30 .61 1.50 1.43 1.34 .06 .06 14.36 1880 10.37 1880-81... .09 .32 .53 .28 4.15 .62 .45 1.88 1.35 .04 .05 9.66 1881 5.00 1881-82... .01 .04 .24 .12 .30 4.63 2.55 1.02 .45 .18 .07 9.51 1882 9.74 1882-83... Tr. .01 .41 .39 .13 1.09 .95 .41 .31 1.14 .08 4.92'18S31 8.01 1883-84... 2.01 .20 1.82 1.34 9.05 6.23 2.84 2.17 .31 25.97 1884 27.59 1884-85... Tr. .07 .35 .11 5.12 .36 .02 .78 1.20 .61 .06 8.6718851 5.73 1885-86... Tr. .13 Tr. .31 1.56 .71 6.95 1.61 3.73 1.96 .04 .07 16.961886 16.35 1886-87... Tr. Tr. .06 .95 .10 .04 4.51 .02 2.14 .47 .04 8.32 18871 10.46 1887-88... .01 Tr. Tr. Tr. 2.08 1.14 1.96 1.48 2.79 .10 .22 .04 9. 82 1888' 11. 57 1888-89... .01 Tr. .04 .26 1.83 2.84 1.72 1.80 2.20 .19 .03 .10 11.02 1889| 16.03 1889-90... Tr. .04 Tr. 2.12 .12 7.71 2.79 1.70 .41 .06 .08 15. 0211890 8.02 1890-91... Tr. .66 .01 .72 1.61 1.21 4.84 .27 .76 .36 .05 10.47!l891 8.99 1891-92... Tr. .08 .04 .10 1.29 1.58 2.96 .96 .41 1.15 .13 8.70 1892 9.09 1892-93... .05 Tr. .22 .91 .69 .78 .47 5.50 .22 .39 Tr. 9. 26 1893 10.29 1893-94... Tr. .11 .91 1.91 .29 .49 1.05 .11 .09 .01 4.97 1894 4.35 106922°— 18— \TSP 426 2 18 SOUTHERN CALIFORNIA FLOODS OF JANUARY, 1916. Precipitation, in inches, at San Diego, Cal., 1850-1916 — Continued. 1 "3 *-> 1 f 1 1 1 1 1 1 1 1 < 03 i 3 1 1 < 1894-95... 0.04 0.01 Tr. 2.26 7.33 0.53 1.43 0.11 0.19 1 11.901895 11.33 1895-96... .01 .27 1.19 .27 1.27 .02 2.89 .25 .03 .01 6. 21 1896 8.73 1896-97... Tr. .13 Tr. .97 .98 2.18 3.13 2.72 1.53 .02 .12 T. 11.78 1897 8.93 1897-98... .01 Tr. Tr. 1.06 .02 .32 1.71 .06 .91 .22 .66 .02 4. 99 1898 4.67 1898-99... .07 .15 .87 2.34 .30 .85 .29 .10 .27 5.24 1899 6.08 1899-1900. .07 .35 .86 .65 .69 .03 .53 1.26 1.45 .08 5. 97*1900 5.77 1900-01... Tr. Tr. .30 1.43 2.08 4.77 1.07 .01 .77 .02 10. 45 1901 9.49 1901-02... Tr. Tr. .06 .28 .41 .02 1.70 1.57 1.86 .21 .06 Tr. 6. 17 1902 11.49 1902-a3... .92 Tr. Tr. .06 1.53 3.58 .69 2.27 1.17 1.40 .14 Tr. 11.76 1903 6.09 1903-04... Tr. Tr. .07 Tr. .35 .04 1.50 2.17 .15 .12 4.401904 6.61 1904-05... Tr. Tr. .17 2.46 2.16 5.90 2.98 .30 .35 Tr. 14.32 1905 16.36 1905-06... .16 .50 .25 3.38 .38 .98 2.62 4.68 .98 .72 .03 14.68 1906 14.90 1906-07... Tr. .10 .12 .03 .62 4.02 3.27 .45 1.62 .13 .07 .19 10.62 1907 7.95 1907-08... .03 1.71 .05 .43 2.80 2.41 .61 .35 .16 8.55 1908 8.59 1908-09... .64 .20 .15 1.00 .27 3.57 1.76 2.62 .02 Tr. Tr. 10. 23 j 1909 14.14 1909-10... Tr. Tr. .02 2.39 3.76 2.00 .19 1.30 .08 .05 9.79 1910 5.75 1910-11... .01 .05 .17 1.35 .40 .15 3.35 4.92 .92 .65 .01 .01 11.99 1911 11.77 1911-12... .12 .10 .28 .02 1.39 .66 5.72 2.13 .17 .16 10.72 1912 10.56 1912-13... .14 .26 .89 .40 .03 1.19 2.40 .42 .08 .07 .09 5.97 1913 7.30 1913-14... .06 .02 .02 Tr. 2.23 .72 3.59 1.90 .36 .85 .08 9.83 1914 10.90 1914-15... Tr. 1.05 .86 2.21 4.91 3.62 .33 1.15 .28 Tr. 14.41 1915 13.62 1915-16... Tr. Tr. .73 2.60 7.56 .66 .98 .01 .01 Tr. 12.55 1916 11.56 1916-17... .02 .01 .25 .87 .05 1.14 " " " ' UJJJJ. Maximum 1.29 1.95 1.59 2.12 3.38 7.71 7.56 9.05 7.88 2.91 2.17 Tes 25.97 27.59 Minimum .01 3.87 3.02 Mean .06 .10 .08 .36 .94 1.80 1.92 1.94 1.46 .62 .31 .06 9.74 .... 9.66 PRECIPITATION. 19 Precipitation, in inches, at Los Angeles, Cal., 1877-1916. 1 1 ^ >> >> ^• jj ot' 1 1 a g 03 i .d a . 2 1 >• 3 < o 1 9 1 1 3 ^ ^ i < 1 June Seas( Year a a < 20.86 1877-78. - . 1878-79. .. 0.86 0.45 3.93 3.33 7.68 2.57 1.71 0.66 1 1 0.07 21.261878 Tr. .14 Tr. 4.70 3.59 .97 .49 1.19 .24 .03 11.35 1879 17.41 1879-80. .. .93 3.44 6.53 1.33 1.56 1.45 5.06 .04 20.34 1880 18. a5 1880-81 . . Tr. Tr. .14 .67 8.40 1.43 .36 1.66 .46 .01 13.13 1881: 5.5.3 1881-82... Tr. Tr. .82 .27 .52 1.01 2.66 2.66 1.83 .63 Tr. 10.40 1882; 10.74 1882-83... Tr. .05 1.82 .08 1.62 3.47 2.87 .15 2.02 .03 12.1l'l883! 14.14 1883-84.. . Tr. 1.42 2.56 3.15 13.37 12.36 3.58 ..35 1..39 38. 18 1884' 40. 29 1884-8.5.. . Tr. Tr. Tr. .39 1.06 4.«>J 1.05 Tr. .01 2.00 .06 Tr. 9.21188.5 10. .53 1885-86 . . Tr. Tr. Tr. .26 5.52 1.& 7.72 1..38 2.50 3.29 .01 22.31 1886 16.72 1886-87... 0.24 0.21 .01 1.18 .18 .20 9.25 .24 2.30 .20 .04 14.05 1887 16.02 1887-88. . . .07 0.15 .12 .78 2.67 6.03 .77 3.15 .11 .02 Tr. 13.87 18881 20.82 1888-89... .03 .08 Tr. .36 4.01 6.26 .25 .92 6.48 .27 .62 19.28 18891 33.26 1889-90. . . .28 .33 6.96 1.35 15.80 7.83 1.36 .66 .22 .03 .02 .34. 84 1890 12. 69 1890-91... .03 .06 .03 .13 2. .32 .25 ■ 8.56 .41 1.26 .31 13. .36 1891 12.84 1891-92... Tr. .06 1.99 .88 3.19 3.39 .22 2.06 .06 11.851892 18.72 1892-93. . . .01 .33 4.40 4.18 6.29 2.27 8.52 .19 .06 .03 26.28 1893 21.96 1893-94.. . Tr. .75 .20 3.65 .94 .49 ..37 .13 .20 Tr. 6. 73 1894 7. 51 1894-95.. - Tr. .01 .73 .02 4.62 5.84 .46 3.77 .46 .19 .01 16.11 1895 12.55 1895-96.. . Tr. Tr. Tr. .24 .80 .78 3.23 Tr. 2.97 .19 ..30 Tr. 8.511896; 11.80 1896-97... .02 .01 Tr. 1.30 1.66 2.12 3.70 5.62 2.31 .02 .10 Tr. 16.86 1897 14.28 1897-98. . . Tt. 2.47 .01 .05 1.26 .51 .98 .03 1.75 Tr. 7.0611898 4.83 1898-99.. . .07 Tr. .02 .09 Tr. .12 2.64 .04 1.81 .18 .04 .58 5. .59 1899 8.69 189^1900. .01 Tr. 1.59 .90 .90 1.17 Tr. .99 .54 1.81 Tr. 7.91 1900 11.30 1900-01-. . Tr. Tr. Tr. .26 6.53 Tr. 2.49 4.38 .45 .68 1.50 Tr. 16.29 1901 11.96 1901-02... Tr. .09 .03 1.88 .46 1.62 3.35 2.98 .16 .03 Tr. 10. 60 1902 13.12 1902-03... Tr. Tr. Tr. .40 2.08 2.50 2.10 1.52 6.93 3.77 Tr. .02 19.321903 14.77 1903-04... Tr. .43 Tr. Tr. .14 2.68 4. .50 .97 Tr. Tr. 8.72il904 11.88 1904-05... Tr. .17 .28 .69 2.45 2. .57 6.06 6.00 ..35 .95 19.52 1905' 19.19 1905-06... Tr. .08 2.98 .20 3.&5 2.47 7.35 .69 1.02 .01 18.65 1906 21.46 1906-07... .02 .03 .05 .85 5.12 7.02 1.83 4.12 .16 .07 .03 19.301907 15.30 1907-08... Tr. 1.19 Tr. .88 5.04 3.66 .18 .52 .25 11.72!l908 13.74 1908-09... Tr. .08 1.22 .25 1.08 1.46 7.27 5.20 2.51 Tr. .11 19.181909 23.92 1909-10... Tr. .04 .28 1.51 7.00 1..53 .11 1.86 .30 12.63 1910 4.89 1910-11... .04 Tr. .01 .82 .15 .07 6.70 2.91 5.15 .28 .02 .03 16.181911 17.85 1911-12... Tr. 1.23 .16 .10 1.27 .07 6.99 1.66 .12 8.60 1912 9.78 1912-13... Tr. .56 .35 .03 2.01 9.16 .33 .35 .05 .58 13.42 1913 17.17 1913-14... Tr. Tr. .03 Tr. 3.00 1.66 10. .35 7.04 ..58 .47 .43 .09 23.65 1914 23.91 1914-15... .01 .31 .20 3.73 5.42 5.09 .60 .81 .88 Tr. 17.05 1915 16.67 1915-16... Tr^_ 1.35 2.52 13.30 1.82 .90 Tr .03 19.92 1916 23.29 1916-17... Tr. . 77 2.71 .09 3.67 """"** " " " " Maximum ^ .28 1.23 6.96 6.53 15.80 13.30 13.37 12. .36 5.oe 2.06 1.39 38.18 40.29 Minimum .07 .01 Tr. 5.59 4.83 Mean .01 .03 .14 .72 1.23 2.78 3.49 3.13 2.92 .94 .44 .08 15.78 15.92 20 SOUTHERN CALIFORNIA FLOODS OF JANUARY, 1916. Precipitation, in inches, at Santa Barbara, CaL, 1S67-1916. j < 1 e eg 1 ® 1 1 O H 1 < 1 1 1 "a 1 1 1867-68. . . «0.02 aO.01 2.31 12.67 3.97 2.00 1.08 2.44 0.72 1 1 <:25. 22 1868 ^?,^'>. 18(>S-G9. . . 1.25 4.26 3.2(1 2.12 4.22 .46 . 2( 15. 77 181.9 11. 78 1869-70. . . i 0.30 .a5 .57 .25i 5.87 .&3 .99 .74 ao? 10 27 1S70 11.47 1870-71... ! 1.04 .27 1.41' .86 2.92 .02 2.02 .37 8.91 187L 14.67 1871-72. . . .09 1.83 6.56 2.53j 1.81 .18 1.80 j .1^ 14.94 1872 10 87 1872-73. . . .02 .05 4.34' .58' 5.48 .05 10.521873 11.64 1873-74. . . 1 .27 5.26 4.54 3.17 .78 .28 .14 14.44 1874 12.12 1874-75. . . 1 1.91 1. 30 1 14. 84 . 18 .38 .10 18. 71 1875 22. 34 1875-76. . . 6.53 .31 7.5(i 5.67 2.73 .2' 23. 07 1876 IC. 55 1876-77. . . .32 2. 72: .82 .18 .45 4.491877 8.61 1877-78. . . 1.32 3.12 7.17 11.73 2.47 3.34 .29 .07 29.511878 30 55 1878-79. . . .32 5. 16! 5. 24 . 71 .34 1.00 .21 13. 58 1879 14. 70 1S79-80. . . .41 1.62' 4.57i 1.30 10.86 1.15 5.71 2o. tU 1S80 29. 30 1880-81... .25 .28, 9.73 2.83: .30 1.25 .5J 15. 23 1881 8.16 1881-82. . . .44 1.47 .33 .95 \.U 2.38 5.74 1.63 .20 14. 27 1882 12.32 1882-83. . . .37 .77 .10 2.18' 2.92 3.64 .2S 2.79 .35 13.4l'l883 16.25 1883-84. . . 1.32 2.76 6.33 9.68 9.77 2.6C .39 1.62 34. 47 1S84 38. 82 1884-85. . . 1.02 .79; 6.62! 1.23 .07 .35 3.0c 13.08 188.^! 17.15 18S.=>-86. . . .19 g.84i 2.47 5.12i 1.19 2.03 3.4C 24.24 1886 13.86 1886-87. . . .39 .87 .86 .31 8.64 .13 1.43 1 -33 .03 12.991887 17.09 1887-88. . . .38 .31 1.10 4.43 10.15 1.30 3.86 .16 .02 Tr. 21.711888 26.80 1888-89... Tr. Tr. .03 .07 5.62 5. 59; .29 1. 29 7.31 .4S .76 .13 21.581889 32.77 1889-90. . . 8.65 3.21 10 64 5.32 2.96 1.10 .31 .18 .06 32. 43 1890 15.49 1890-91... 1.50 .05 .48 3.53 .45i 7.92 1.56 1.57 ..30 17.361891 14.38 1891-92. . . .15 2.43 1.10 2.55 2.95 .46 1.12 10. 76 1892 19.37 1892-93. . . .26 4.27 6.66 4.41 3.10 7.80 .38 .09 26.971893 19.61 1893-94. . . .82 . 07 2. 94 .99 .76 .29 .24 .91 7. 02 1894 10 09 1894-95. . . .12 Tr. 1.36 .68 .07 4.67 6.25 .67 1.99 .46 .02 .05 16.34 1895' 11.69 1895-96. . . Tr. .55 .771 .93 6.84 2.37 1.78, .08 .05 13.37 1896 18.87 1896-97. . . .40 .92 3.51 2.92 4.35 3.65 2.73 .02 i 18.501897 12.19 1897-98... 1.44 .63 1.39 .28 Tr. L25 4. 99 1898 7. 22 1898-99. . . Tr. 3.17 .14 .36 4.48 2.78 .64 .78 12.35 1899 15.06 1899-1900 . 2.06 1.97 2.35 2.32 .05 1.58 .42 1.90 .01 12.661900 10 50 1900-01... .02 Tr. .04 .15 3.99 .02 4.86 3.65 .16 2.07 .34 .10 15.401901 15.27 1901-02. . . .06 .09 .36 2.42 1.16 Tr. 1.36 4.40 2.89 1.40 .07 14.2119021 17.85 1902-03. . . L48 4.01 2.24' 2.06 1.63 6.12 2.91 ' .27 .02 20.741903' 13.06 1903-04. . . Tr. Tr. .05 Tr. 1 .46 4.69 4.40 1.89 .09 11.5,S1904' 20.82 1904-05. . . .10 7.15 .51 Tr. 1. 53 3. 73 8.22 6.40 .51 1.44 .05 29.64 1905, 21.93 1905-06. . . .18 .03 .16 1.14 .07 4.26 3.67 9.96 .83 2.40 Tr. i 22.70 1906 27.97 1906-07. . . Tr. .01 .35 6.46j 12.46 2.34 5.64 .27 Tr. .lej 27.721907| 28.93 1907-08. . . .03 Tr. 6.23 Tr. I.80' 4.29 5.96 .21 .49 .20 19.211908! 16.83 1908-09... 1.16 .20 1.84 2.48 15.67 7.92 6.91 .03 .08 36. 29 1909 43. 23 1909-10... Tr. .01 .17 .57 2.34 9.53 2.91 .08 3.62 .39 19.621910 1095 1910-11. . . .02 Tr. 2.56 .29 .33 .75 14.21 4.92 .7.76 1.02 .03 .05 31.94 1911 30 74 1911-12. . . Tr. .12 .28 .02 2.33 .42 9.48 2.12 L58 Tr. 14.35 1912, 14.09 1912-13. . . Tr. Tr. .28 .21 Tr. 3.14 6.58 .64 L04 .19 .50 12. 58 1913' 18.56 1913-14... .09 .07 .17 Tr. 3.43 2.71 15.91 7.30 .95 .70 .03 .16 31. 52 1914! 29. 64 1914-15... .05 .12 .04 4.38 4.94 8.03 1.89 1.15 .97 1.57 Tr. 21.251915 21.42 1915-16. . . .05 .()5 4.06 17.24 1.71 .30 Tr. 25.90,1916 32.19 1916-17...' .11 1.90 2.82 in' 6.12 1 1 i Maximum .40 .11 7,15 8.65 9.84i 12.67 17.24 11.73 9.96 5.73 2.79 1.62 36.29....I 43.23 Minimum .25 .02 4.49 7.22 Mean .02 .01 .42 .82 1.42 3.27 4.68 3.56 2.92 1.14 .44 .10 18.64 .... 18.60 a Interpolated. INTENSITY AND DISTRIBUTION OF IIAINFAI.L. The magnitude of the flood resulting from a given amount of precipitation is determined largely by the intensity of the rainfall and its distribution through the month. The records of the United States Weather Bureau, supplemented by records from private parties, give the information concerning excessively heavy rainfall PRECIPITATION. 21 at San Diego, Los Angeles, Squirrel Inn, and Campo, which is pre- sented in the following paragraphs : San Diego. — A self -registering rain gage was installed in San Diego in 1893, but was not in operation during the storms of January, 1916, so that the rate of fall is unknown. The total rainfall recorded from January 15-18, inclusive, was 2.90 inches. Records collected by William A. Edwards, M. D.,^ give the follow- ing maximum records for 24 hours rainfall: Inches. Dec. 3, 1873, 10 p. m. to night of Dec. 4 2.52 Nov. 9, 1879, morning to 8.10 p. m 2. 75 Dec. 27, 1879, 6 a. m. to Dec. 28, 6 a. m 2. 55 Jan. 12, 1882, 3.50 a. m. to Jan. 13, 3 a. m ^2. 49 The heavy rain of December 28, 1896, was the maximum recorded to that date on the self-registering gage and fell at the following rates: 1 minute, 0.19 inch; 5 minutes, 0.32 inch; 10 minutes, 0.47 inch; 1 hour, 0.79 inch. Records in the San Diego office of the United States Weather Bureau show that on March 15, 1905, the rate of fall was as follows: 5 minutes, 0.32 inch; 10 minutes, 0.41 inch; 15 minutes, 0.58 inch; 30 minutes, 0.74 inch; 1 hour, 0.94 inch; 2 hours, 0.95 inch. A rate of 1 inch in an hour has never been recorded at San Diego. Los Angeles, — ^The heaviest rainfall during January, 1916, began at 1.05 p.m., January 16, and ended at 9.30 a.m., January 18; the total for this period was 5.74 inches. From 3.17 a. m. to 3.29 a. m. the rate was as foUows: 5 minutes, 0.20 inch; 10 minutes, 0.42 inch,; 15 minutes, 0.46 inch."^ Other heavy rainfalls, occurring in 1889, have been reported by the Los Angeles office of the United States Weather Bureau as follows: From December 11,8 p. m., to December 12, 8 p. m., total rainfall 4.30 inches. From December 24, 8 p. m., to December 25, 8 p. m., 2.72 inches. The rainfall on December 24, from 9.45 p. m. to 10.45 p. m., is estimated at 1 to 1.25 inches. Squirrel Inn. — ^The total precipitation from January 14-19, inclu- sive, at Squirrel Inn, north of San Bernardino, on the south slope of the San Bernardino Mountains, at an elevation of 5,280 feet above sea level, was 27.80 inches, or an average of 4.63 inches for each da}". The 24-hour precipitation January 16-17 was 16.81 inches, one of the heaviest for that period of time ever recorded in the United States, and a new record for California. Campo. — ^A rainfall of the '^Sonora" type occurred at Campo August 12, 1891. The total rainfall for this storm, which lasted more 1 Reprintod in Littoral California, p. 3, from the Philadelphia Medical Journal, Oct. 11, 1902. a Correct: amount published in LittoralCalifornia in error. ' Abstracted from United States Weather Bureau Monthly Weather Review, vol. 44, No. 1, p. 57, Jan- uary, 191G. 22 SOUTHERN CALIFORNIA FLOODS OF JANUARY, 1916. than 24 hours, was 16.10 inches, according to Mr. Archibald Campbell, cooperative observer. In a period of about 80 minutes the rainfall was 11. .50 inches. In the following table the daily distribution of rainfall during the mouth of January, 1916, is compared with that of the months of December, 1SS9, and February and March, 1884, which were the months of previously recorded maximum rainfall : Daily precipitation, in inches, for months of maximum rainfall at San Diego and Los Angeles, Cal. San Diego. Los Angeles. Day. Decem- ber, 1889. Janu- ary, 1916. Febru- j ary. 1884. March, 1884.a Decem- ber. 1889. Janu- ary, 1916. Febru- March, 1884. 1 '. 0.94 . .'62" ; .12 . 0.44 , .43 i 1.52 1 .65 1 .34 .80 .16 1.11 . 77 Tr. .11 0.60 1.07 1.61 2.*t .45 .29 .60 .70 .62 2 3 '"'o'oi' Tr. 34 . 17 .25 .57 .09 Tr. .79 .15 Tr. 1.78 4 5 .'26 1.97 1 98 6 .59 . .10 . .52 r '.U '. 1.18 1.75 .07 .'62' .01 Tr. . .01 . .06 .37 .as .46 88 .26' .27 .18 16 S .41 .29 .17 9 2 67 10 .37 ! .50 .01 1 .49 .07 Tr. .05 11 .02 4.30 .59 :f2 12 13 14 15 Ui 17 .53 .09 .95 1.55 .31 .80 .12 1.35 .96 1.31 .09 1.39 .35 .38 .04 1.07 4.16 .82 .43 .05 2.02 1.38 2.18 .07 1.00 .12 ."64 18 19 .01 .io .01 .01 Tr. 20 21 22 ........... 1.61 1.10 2.72 .51 23 1.13 . .44 .53 ! .05 1 .03 1 Tr. ! "Tr!"'" .21 .22 2.19 .06 .17 .26 .01 .11 .33 .33 2.28 .05 24 25 ."72" Tr. .50 .26 .02 .36 .10 2«; . . .05 27 .51 28 .75 29 .43 Tr. 30 .03 31 .00 j. .04 Total 7.71 7.56 9.05 : a23 15.80 13.30 13.37 12.36 a Total for March, 1867, was 7.88 inches, but daily record is not available; March, 18^, was the next highest. FLOOD OF JANUARY, 1916. CREST DISCHARGE. The heavy storms of January, 1916, fell on ground already satu- rated, and the water was therefore rapidly carried into the stream channels. Detailed information concerning the discharge of the streams during these storms is given in the run-off records (pp. 40-78) and is siunmarized in the following tables, which show the crest dis- charge of the streams and the total nm-off compared with the rainfall. CREST DISCHARGE. 23 Crest discharges, in second-feet, of streams in southern California for January, 1916. Station. Cottonwood Creek at Morena reservoir. Otay River at Lower Otay reser- voir, Jamul Creek near Otay Sweetwater River nearDescanso, Sweetwater River near Dehesa... Sweetwater River at Rudolph ranch. Sweetwater R iver near Jam acho . Sweetwater River at Sweetwater reservoir. San Diego River at diverting dam. Do San Diego River at Capitan Grande dam site. San Diego River near Santee San Diego River at SanDiego Boulder Creek at Cuyamaca reservoir. San Vicente Creek at mouth Switzer Canvon at San Diego Santa Ysabel Creek near Mesa Grande. Do Santa Ysabel Creek nearRamona. Do San Diegtiito River at Carroll dam site. Santa Maria Creek near Ramona . San Luis Rey River near Mesa Grande. Do San Luis Rey River near Pala. . . San Luis Rey River at Ocean- side. Do Santa Ana River near Mentone . . Santa Ana River at San Ber- nardlBo. Lytle Creek at San Bernardino. . San Jacinto River near San Jacinto. San Jacinto River near Elsinore. . South Fork of San Jacinto River at Hemet resers-oir. San Gabriel River near Axusa. . . LosAngeles River at LosAngeles. Los Angeles River near Domin- guez Junction. Arroyo Seco near Pasadena Arroyo Seco at Los Angeles Sespe Creek near Sespe Date. Time. Jan. 27 4-6 p.m. ...do....' ..do. ..do. ..do. ..do. ..do. ..do. 4.30-5.30 p.m. Jan. 18 : 6 a. m Gage height (feet). Jan. 28 I 6p.m. Jan. 27 --do '...do "p. m. 25.1 Drainage area Dis- (square charge, miles). .do. 6p.m. ...do ...do. ... 7 a. m. Jan. 17 Jan. 27 Noon... Jan. 17 j 9p.m.. Jan. 27 I 7p.m.. ...do 1-3 p.m. ...do... . 5 p. m Jan. 17 1.45 p.m. 11.0 Jan. 27 4.30 p.m. ...do Jan. 17 21.2 15.9 12.8 18.0 18.1 ' Jan. 27 9.30 p.m. Jan. 17 !...do I Jan. 18 9.40 a. ra. Jan. 28 11 a. m. Jan. 27 4 p.m., Jan. 18 7 a. m. 19.0 12.0 Jan. 17 9.30 a.m. Jan. 17 9.3 "is." 7" 120 69.8 43.7 112 135 172 181 102 375 4.34 12 74.9 3.55 53.4 53. 4 110 110 299 57.3 209 15,356 023,500 18.100 9,870 24,29.5 27,530 43.002 45.500 4,710 565 565 189 106 717 65.8 16.4 *2i6"' Run-off per square mile. 128 238 259 226 217 204 250 2.51 46 15.800 636.300 155 192 70.200 75,000 2,393 187 173 199 18.600 668 10,600 248 188 199 21,100 14,300 28.400 72,100 395 130 258 241 7.140 24,400 125 117 58.600 75,000 40,000 280 233 71 95,600 29,100 40.000 169 154 16 000 30.000 278 14,000 9,550 195 1 ''' 40,000 7.268 1 180 31.113 3.150 6.215 18,600 1 192 a Reported by George Cromwell, city engineer, San Diego, (See Engineering News, vol. 75, No. 15, p. 718.) b Mean of two estimates computed from cross sections and slope data. 24 SOUTHERN CALIFORNIA FLOODS OF JANUARY, 1916. Sumvmry of run-off of streams in southern California for January, 1916. Period (Janu- ary). Drainage area (square miles). Rim-oflf. Mean rainfall Station. Totalin acre-feet. Depth in inches on drainage area. Per cent of mean rainfall. on drain- age area January 14 to 30 (inches). Cottonwood Creek at Morena reservoir lto31 16 to 31 lto31 lto31 13 to 31 lto31 lto31 lto31 lto31 lto31 lto31 lto31 lto31 16 to 31 14 to 31 lto31 120 181 102 434 12 53.4 110 299 57.3 209 240 322 465 565 65.8 222 41,200 111.000 92,800 213,000 12.300 66,400 104,000 257,000 33,500 141,000 165,000 201,000 257,000 269,000 29,100 148,000 0.43 11.55 17.06 9.19 19.22 23.29 17.75 16.14 10.96 12.68 12.91 11.76 10.36 8.92 8.30 12.57 Sweetwater River at Sweetwater dam 53 62 46 21.8 27.6 19.9 San Diego River at San Diego Boulder Creek near Julian Santa Ysabel Creek near Mesa Grande 77 69 68 52 51 51 46 43 39 30.3 25 8 San Dieguito River near Bernardo Santa Maria Creek near Raniona . . 23.6 21 2 San Luis Rev River near Mesa Grande San Luis Rev River near Nellie . 24.9 25 4 San Ltiis Rey River at Pala.'. 25 7 San Luis Rev River at Bonsall 24 3 22.6 South Fork of San Jacinto River at Hemet San Gabriel River near Azusa CONDITION OF RESERVOIRS DURING FLOOD. MORENA RESERVOIR. The Morena reservoir, on Cottonwood Creek 8 J miles upstream from the Barrett dam, has a capacity of 46,000 acre-feet. It forms a part of the municipal water-supply system of San Diego. ^ The following is a description ^ of the flood of January, 1916, at this reservoir: The flood brought into the resen'oir a large quantity of debris which accumulated in front of the racks that protect the radial gates, and so choked the flow that when the reservoir level was 3 feet above the spillway level the flow actually passing over the spillway beneath the open gates was only 3 inches deep. Under these conditions the water rose within 18 inches of the parapet crest and waves actually carried debris over the top. Two effects of this pressure are apparent. A downstream movement of the upper face of the dam which showed in the alignment of the parapet as about 2 or 3 inches at the center of the structure, and a settlement of the top of the rock fill amounting to 2 or 3 inches. The amount of leakage could not be observ'ed, but George Cromwell, city engineer of San Diego, who was at the dam during the high water, affirmed that he believed such leakage as there was came through the face of the structure and not around the ends or from beneath. Leakage some time prior to recent storms amounted to 1,500,000 gallons per day. After going down to the bottom of the intake tower during the height of the flood, Mr. Cromwell reported that structure was standing the pressure well, only slight seep- age appearing. The intake gates were all in working order and all were left open to lower the reser\-oir level as much as possible. The debris was being removed by as large a force of men as could be readily assembled. Orders to lower the reservoir 3 feet below the spillway level by means of the intake gates were left at the dam. > O'Shaughnessy, M. M., Construction of the Morena rock-fill dam, San Diego County, Cal.: Am. Soc. Civil Eng. Trans., vol. 75, p. 27, 1913. » Eng. Record, vol. 73, No. 7, p. 228, February 12, 1916. U. 8. GEOLOQICAL SURVEY WATER-SUPPLY PAPER 426 PLATE l( A. VIEW UP LOWER OTAY RESERVOIR, AFTER FAILURE OF DAM. Reservoir gage in foreground. B. VIEW DOWNSTREAM AT SITE OF LOWER OTAY DAM, AFTER FAILURE. Spillway at extrenne left U. S. GEOLOGICAL SURREY WATER-SUPPLY PAPER 426 PLATE III A. SWEETWATER DAM, AFTER FLOOD OF JANUARY, 1916. B. BREAK AT RIGHT END OF SWEETV/ATER DAM, AFTER FLOOD OF JANUARY, 1916. CONDITION OF RESERVOIRS. 25 LOWER OTAY RESERVOIR. Two reservoirs known as Upper and Lower Otay have been con- structed as a part of the water-supply system for the city of San Diego. Upper Otay is at the lower end of Procter Valley and Lower Otay* is on the main stream directly south. The capacity of the for- mer is about 3,300 acre-feet; that of the latter about 40,000. Lower Otay dam was overtopped by the flood on January 27, 1916, and destroyed. The following is a description of the failure of Lower Ota}^ dam byRoyA. Sdentr^ The rain on January 27 was extremely heavy, and by noon the water had risen so high that Mr. Weuste, in charge at the dam, deemed it advisable to open the outlet gate. This failed to check the rise, and it was realized that the dam would probably be overtopped before evening. Men were accordingly dispatched to warn residents in the valley to move to higher ground. Word to this effect was also sent out from the telephone exchange at National City. Most of the inhabitants took advantage of this warning. At 4.45 p. m. the water had reached the top of the dam and had seeped through and filled the boxes that were sunk in the top to allow an examination of the steel core. Water began running down the lower face on the east side of the dam at approximately 4.50 p. m. About this time several spouts or small streams of water appeared on the lower face of the dam, in one instance loosening a large bowlder which rolled down to the bottom. From this time on, the destruction was very rapid. The lower face of the fill quickly melted away, thus removing the support from the core wall. At 5.05 p. m. the tension was so great that the steel diaphragm tore from the top at the center, and the dam opened outward like a pair of gates. The released water rushed through and filled the canyon to a point approximately 20 feet below the top of the dam. It required 2^ hours for the reservoir to empty. A huge wall of water, variously described as from 6 to 20 feet high, rushed down the valley, covering the distance from the dam site to Palm City, about 10 miles, in 48 minutes, carrying all before it. * * * A thorough examination of the dam site was made on January 31 and February 1. Practically all the fill was washed completely away. The steel core was deposited in varpng-sized sections along the valley, a large part being found at Palm City, 10 miles below the dam. The core wall had torn itself loose from both of the side walls, the foundations remaining intact. * * * Three-quarters of a mile below where the dam had stood a piece of the diaphragm was observ^ed, to which the angle iron forming the bottom of the steel plate was riveted, showing that the extreme bottom had been torn loose. On the west side, behind the remaining core wall, was a small part of the fill, composed of rock of small sizes, none of which was over IJ feet in diameter and grading from that size to coarse gravel. If this may be considered a fair sample of the remainder of the fill, it is easy to under- stand its melting away as rapidly as described. The canyon below the dam, prior to the failure, was considerably restricted and filled with large boulders. The action of the water removed all the loose rock and thoroughly stripped to bedrock both sides of the canyon as high as the water reached, the line of demarcation being clearly defined. The stripping was done in a most thorough manner, no particle of soil remaining in any of the niches or crevasses. This area was hea\ily wooded with brush. [See PI. II, B.] 1 Schuyler, J. D., Reservoirs for irrigation: U. S. Geol. Sun-ey Eighteenth Ann. Rept., pt. 4, pp. 637-640, 1S97. » Eng. News, vol. 75, No. 7, pp. 334-33G. February 17. 1916. 26 SOUTHERN" CALIFORNIA FLOODS OF JANUARY, 1916. An interesting feature was observed in that for lialf a mile below the dam in practi- cally every pocket or niche in the rock was to be found a ri^-et head. An examination of the remaining parts of the steel core showed it to be in a perfect state of preservation, no rust or corrosion being noticeable. The destruction of the plate for the most part had taken place along the riveted seams, though one or two cases in which the sheets had torn were observed. Other accounts of the failure have also been published.* SWEETWATER RESERVOIR. The celebrated Sweetwater masomy dam is on Sweetwater River about 8 miles above its mouth at an elevation of 145 feet.^ The follomng description of the breaks in Sweetwater reservoir was prepared from information supplied by Mr. J. F. Covert, chief engineer, Sweetwater Water Co.:^ On January 27 the flow into the reservoir exceeded the combined capacity of spill- way and blow-off valves, and the level behind the dam raised imtil the parapet was overtopped at 2.20 p. m. At 4.30 p. m the flow over the parapet had increased to a depth of 3.5 feet, and the 50-foot length of earth-fill dike at the north end of the struc- ture was overtopped. The water washed away this fill, broke the concrete-core wall, and cut a by-pass around the dam through the bedrock foundation. The break is about 75 feet wide, with a maximum depth of 30 feet below the level of parapet. [See PI. III.] This break was made by degrees, no water appearing below the dike until it was actually overtopped, and the cutting into the foundation was gradual. At 7 p. m. the reservoir level was lowered only 0.3 foot. Water flowed over the parapet about seven hours after the break occurred, it is believed, which would mean that the flood continued to overtop the dam for about nine hours. An earthen dike 650 feet long stood some distance from the dam, where a low point in the ridge occurred. This dike had a puddled-clay core and was 23 feet high at its mid-point. At 3.50 p. m. on the day of the flood peak the water level reached the top of this dike and began to spill over the downstream slope. This melted as the water continued to rise, and when the flood subsided the dike had been swept out cleanly except for about 10 feet of its length. The material on which the dike stood was eroded by the outpouring water to such an extent that the reservoir rim at this point is now 15 feet below the spillway level. CITYAMACA RESERVOIR. Cuyamaca reservoir is formed by an earthen dam on Boulder Creek, a tributary of San Diego River. The capacity given by a 35-foot dam is 11,400 acre-feet.^ The effect of the flood on this reservoir has been described as follows : ^ The impending danger of the recent flood was realized in time to draw down the Cuyamaca reservoir considerably. In fact, the amoimt drawn off by the blow-off 1 Eng. News, vol. 75, No. 5, pp. 236-239, Feb. 3, 1916; Eng. Record, vol. 73, No. 7, p. 226, Feb. 12, 1916. « Schuyler, J. D., Reservoirs for irrigation: U. S. Geol. Survey Eighteenth Ann. Rept., pt. .4, pp. 669- 682, 1897; also details of design and last increase in height, in Eng. Record, Sept, 2, 1911, p. 264. » Eng. Record, vol. 73, No. 7, p. 225, Feb. 12, 1916. ♦ Schuyler, J. D., Reservoirs for irrigation: U. S. Geol. Survey Eighteenth Ann. Rept., pt. 4, pp. 698- 700, 1897. i Eng. Record, vol. 73, No. 7, p. 228, Feb. 12, 1916. DAMAGE DUE TO FLOOD. valve through the dam was about 1,000,000,000 gallons. The peak of the flood brought the reservoir level up to within 14 inches of the crest of the dam, with both spillways flowing over 4 feet deep. A few washouts on the conduit constituted the only dam- age suffered by this system, which includes, in addition to the Cuyamaca dam, three smaller reservoirs on tributaries of the San Diego River. DAMAGE DUE TO FLOOD. An inventory of the damage in Los Angeles, San Bernardino, River- side, Orange, and San Diego counties, believed to be practically complete except for minor losses, is given in the following pages. Every effort was made to obtain the best information available, and all public officials, engineers, and others to whom requests were made for estimates regarding losses in their departments or business gave hearty cooperation. A number of the statements were prepared within a few months after the storms, and hence were based upon estimated costs rather than actual expenditures. The loss of life was determined from reports obtained from the coroners of each county. The total direct damage is estimated at about $10,000,000. This estimate is based on the best available information, which is summa- rized in the following table: Summary of flood damage in southern California January, 1916. Character of damage. San Diego County. Orange County. Riverside County. San Bernardino County. Los Angeles County. Total. Lives lost 22 $1,500,000 72,850. 1,225,500 4 $350,000 32,000 57,000 $350,000 50,000 67,450 2 $150,000 $500,000 19,000 28 Agricultural lands $2,850,000 173,850 1,349,950 96,165 ■\Vater supply . . ...... 94,565 1,600 Railroads a 1,795,201 652,350 81,500 128,600 155, 130 254,638 1,272,218 TelefiTaph and telephone lines a Misoellaneous 126,100 231,427 9,000 200 240,627 o The damage to railroads and telegraph and telephone lines was not reported in such shape that it could be segregated by counties. LOSS OF LIFE. Twenty-two persons were drowned in San Diego Coxmty. Most of them were living in Otay VaUey and were swept away by the flood wave which was released from Lower Otay reservoir when the dam failed. A few lives were lost in Mission VaUey, on San Luis Rey River. Li Orange County four persons were drowned; two were in a cottage which floated down Santa Ana River, one was swept from the highway by the force of the water, and the other was in a wagon which was overturned. In San Bemardmo County two men were drowned. No deaths were reported in Riverside and Los Angeles counties. 28 SOUTHERN CALIFORNIA FI.OODS OF JANUARY, 1916. AGRICULTURAL LANDS. San Diego County. — ^The valley lands along Tia Juana, Otay, Sweet- water, San Diego, San Dieguito, and San Luis Rev rivers were flooded. A large part of the bottom land was either cut up by new stream channels or covered with a large amoimt of sand, brush, and trees. A part of the land in each valley was quickly cleared, but there is a large area reclaimable only by large expenditm-es of time and money, and there are other large areas whose agricultm-al value was almost completely destroyed. An example is afforded by a tract of land in Otay Valley formerly used as a truck garden and valued at S 1,000 per acre; after the flood 11 acres of this land were sold at a foreclosm-e sale for $100. The total damage to farm land was approximately $1,500,000. (See Pis. IV, V, VI.) Orange County. — ^The total damage to agricultural lands in Grange Coimty was approximately $350,000. Biverside County. — ^The damage to lands in Rivei'side County is believed to have been at least $350,000. San Bernardino County. — ^The damage to orange groves m San Ber- nardino County was considerable, and a number of the alfaT" i ranches were practically ruined. The total damage was about $150,000. Los Angeles County. — ^The principal injury to lands in Los Angeles County resulted from deposits of silt and the cutting of new stream channels. The damage was approximately $500,000. MUNICIPAL PROPERTY. San Diego. — The 300-foot concrete arch bridge across San Diego Kiver at Old Town was wi-ecked (see PI. VII, ^4) and five other bridges and numerous culverts were destroyed or seriously injured. The streets and roads in various parts of the city were washed or covered with debris. An approximate estimate of the total damage was $72,850. San Bernardino, — ^The water main and several smaU pipe lines were washed out; two bridges were completely destroyed; and several sidewalks, cm^bs, and streets were damaged or destroyed. In addition several houses were washed away. The total damage was approxi- mately $32,000. San Jacinto. — The damage to the water-supply systems, streets, and private property within the city hmits was approximately 850,000. Pomona. — The principal damage resulted from washes and fills in the streets. The estimated cost of repairs was $15,000. Pasadenxi. — The damage to street improvements amounted to about $1,000, but otherwise there was no loss within the cit}". U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 428 PLATE IV A. VIEW UP MISSION VALLEY, SAN LUIS REY RIVER, IN 1915. B. VIEW UP MISSION VALLEY, SAN LUIS REY RIVER, FEBRUARY 21, 1916. U. 8. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 426 PLATE V A. VIEW ACROSS MISSION VALLEY. SAN LUIS REY RIVER, AT D. JONES'S RANCH, AFTER FLOOD OF JANUARY, 1916 B. VIEV/ UP SAN LUIS REY RIVER AT JUNCTION V^ITH MOOSA CANYOixl CREEK, AFTER FLOOD OF JANUARY, 1916. DAMAGE DUE TO FLOOD. 29 Los Angeles. — ^A few unimportant wooden bridges were washed out and new channels formed. The damage was reparable at a cost of 83,000, which includes the removal of debris that collected at pile bents of several bridges. WATER STTPPLY. City of San Diego. — The failure of Lower Otay dam and the loss of the stored water was the most important damage (PI. II). About 18 miles of Didzura conduit was filled with debris and 2,800 feet of flume and concrete-lined section was destroyed. The road up Cotton- wood Creek to Morena was seriously washed and blocked by slides. The washout of the pipe line across Sweetwater Valley prevented the delivery of water from this system. The loss of wells, pumps, and collecting pipe lines at the IVIission VaUey plant shut off the supply from this source. The total estimated damage was $897,500. Sweetwater Water Co. — The north abutment of Sweetwater dam, consisting of a concrete-paved earth fill with reinforced concrete core wall, was overtopped to a depth of 3.64 feet and destroyed. The released water eroded the bedrock, foundation at this end of the dam, leaving an opening about 50 feet deep and 100 feet long. SHght damages to the south abutment and spillway did not reduce the capacity of the reservoir. An earth dike, 650 feet long and 23 feet high, on the south side of the reservoir, about a mile above the dam, was overtopped and completely washed out. These breaks reduced the capacity of the reservoir from 35,000 acre-feet to 12,000 acre-feet. Temporary repairs increased the reservoir capacity to 25,000 acre- feet. In Sweetwater Valley 15,140 feet of pipe lines were washed out and other sections shifted or filled \sdth sand. An approximate estimate of the cost of necessary repairs and enlarged spillway was $200,000. (See PI. Ill, p. 25.) Cuyamaca Water Co. — The principal damage was the loss of flume along upper San Diego Kiver. The estimated cost of repairs to flume and pumping plants was $60,000. South Coast Land Co. — ^The water supply for the town of Del Mar is obtained from wells on Santa Fe ranch in San Dieguito Valley, 6 miles above the mouth of the river. This pipe Hne was practically washed out. The new pipe line, completed about the middle of May, follows a new course along the foot hills. The high water on January 17 did not damage the steam pumping plant in San Luis Rey Valley, but that of January 27 completely wrecked this plant and 2,000 feet of 16-inch pipe. Only one small section of the concrete building remained above the sand after the flood. The boilers were found 50 feet from their original position and covered with 30 feet of sand. The total damage to property of this company was about $60,000. 30 SOUTHERN CALIFORNIA FLOODS OF JANUARY, 1916. Escondido Mutual Water Co. — The principal damage was caused by slides which either filled or destroyed sections of the canal. About 8,000 yards of rock and earth were removed from the canal. Repairs were completed April 18 at a cost of about S8,000. Temescal 'Water Co. — The main pipe lines and ditches were but slightly damaged. The loss on the tributary Hues was much greater. In Mahew Canyon, 1,100 feet of 8-inch pipe was washed out. The dam at Lee Lake in Temescal Canyon failed, and a mile or more of 18-inch pipe hue below the dam was washed out. The total damage was about 813,750. Riverside Wat^ Co. — The damage reported, including the rebuilding of the headworks, was approximately 810,000. Lake Hemet Water Co. — The damage to headworks, canal, and pipe hues was about 843,700. An-aJieim Union Water Co. — The concrete head gate was imder- mined and washed out, several thousand feet of main canal were seriously injured, and considerable damage was done to the distribu- tion system and roads. The total damage was about 857,000.^ POWER PLANTS. Pacific Light d: Power Corporation. — The Mentone plant on Santa Ana River was stopped on January 17 and started April 1. The masonry diversion dam, two masonry sand boxes, and 400 feet of concrete-lined canal were wrecked. A corner of the power plant was undermined, but the building was uninjured. The semicircular wood stave flume crossing the river from power house to North Fork ditch was completely carried away. The road up the canyon to the intake was practically all washed out. The transmission line was damaged but Uttle, as it was on high ground. The total cost of repairs to this plant was 825,000. The intake and 200 feet of pipe line were washed out at the Sierra plant on San Antonio Creek, as was also the road up San Antonio Canyon. The total cost of repairs was 81,600. Southern California Edison Co. — The headworks and flume No. 8 at Santa Ana River plant No. 1 were destroyed, the buildings were seriously damaged, and a large amount of debris was deposited in the tailrace and on the floor of the power house. The siphon across Santa Ana River from the tailrace of plant No. 1 to intake of plant No. 2 collapsed. Plant No. 2 was not othersvise damaged, although a severe wash threatened to undermine the power house. The flimie across the wash between !Mill Creek power houses Nos. 2 and 3 was completely wrecked, and the pressure pipe line was washed out in several places. There were also minor damages to the headworks and various sections of flume on the canal lines. The intake for the 1 From report to directors and stockholders on construction wwk toe 1916. U. 8. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 426 PLATE VI A. WINSTON RANCH, MISSION VALLEY, SAN LUIS REY RIVER, FEBRUARY 21, 1916. B. CANFIELD RANCH, NEAR BONSALL. SAN LUIS REY RIVER, FEBRUARY 21, 1916. U. 6. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 426 PLATE VII A. SAN DIEGO RIVER AT SAN DIEGO, AFTER FLOOD OF JANUARY, 1916. Showing damage to county and Atchison, Topeka &i. Santa Fe RaiKvay bridges. B. SANTA MARGARITA RIVER NEAR MOUTH, AFTER FLOOD OF JANUARY, 1916. Showing danaage to State highway and Atchison, Topeka 8c Santa Fe Railway bridges. DAMAGE DUE TO FLOOD. 31 Lytle Creek plant was seriously injured and the tailrace siphon was destroyed. Many of the wooden poles in the transmission line do>\Ti Santa Ana Canyon were washed out. Several towers were also un- dermined along lower Santa Ana, San Gabriel, and Los Angeles rivers. The damage to the entire system was approximately So6,200. Southern Sierras Power Co. — The damage to the system of the Southern Sierras Power Co. was principally confined to the transmission lines. Temporary repairs were completed in three days. The esti- mated damage was $13,365. RAILROADS. AtcTiison, Topelca & Santa Fe Railway Co. — The greatest damage to property belonging to the Santa Fe Railway Co. was on the line between Los Angeles and San Diego, where several miles of track, including many bridges and trestles, were entirely washed out. On the Fallbrook branch, which is 18 miles long, 4,500 feet of bridges was lost, 6^ miles of track disappeared, 4 J miles was washed off roadbed, and 4.V miles covered with sand. The damage in the other districts was less severe. Traffic was restored on the double track between San Bernardino and Barstow February 2 ; between San Ber- nardino and Redlands February 3 ; and on Temecula branch Febru- ary 29. The line between Los Angeles and San Diego, including Escondido branch, was restored to trafiic February 19. An approxi- mate estimate of the total damage, made shortly after the flood, was $1,000,000. This estimate was based simply on replacing the track and roadbed to its original position and did not take into account any work that will be necessary to protect the track from future floods. (See Pis. VII and VIII, A.) Southern Pacific Co. — The damage to the Southern Pacific system was estimated at $216,000. The first through eastbound passenger train after the flood left Los Angeles January 30, was held at Colton until 6.20 p. m. the following night and arrived at Yuma, Ariz., at 7.59 p. m. February 1. The first westbound passenger train after the flood reached Los Angeles at 1 a. m. February 1. The Tustin branch was opened to traffic February 7. The coast and valley lines north of Los Angeles were not seriously damaged. Los Angeles db Salt Lalce Railroad Co. — The excessive run-off began to weaken the structures on the Salt Lake line on January 17. In the Pasadena district traflSc was delayed imtU January 21; in the first district — Los Angeles to Riverside — until January 22 ; and in the San Pedro district until January 28. Several bridges were injured and track was badly washed in many places. The total estimated cost of the repairs necessary to restore the lines in Los Angeles and River- side counties was $50,000. 32 SOUTHERN CALIFORNIA FLOODS OF JANUARY, 1916. Pacific Eh'ctric Railway Co. — This company, in addition to its city lines, controls an extensive suburban system extending in all directions from Los Angeles. It serves parts of Los Angeles, San Bernardino, Kiverside, and Orange counties. There were many interruptions to traffic during the flood period caused by washouts, flooded tracks, slides, and injury to bridges. Through traffic to Los Angeles over the Riverside-Rialto line, stopped by the loss of the Santa Ana bridge on January 17, was not completely resumed until March 3. Through service on the San Pedro-Los AJageles line was resumed January 31. The Newport line was not restored at Signal Hill until April 5 and was then operated with a single track until May 19. The total damage to property of this company was about $141,575. San Diego <& Southeastern Railway Co. — The total trackage of this company, including sidings and spurs, was 92.99 miles. The flood washed out 19.65 miles, or more than 21 per cent of the total track. The damage to the eastern division was caused principally by the floods on San Vicente Creek and San Diego River. AH tracks in the Sweetwater Valley were washed out by the water released from Sweetwater reservoir after the break in the upper section of the dam. The failure of the Lower Otay dam resulted in the loss of all tracks in Otay VaUey. The total estimated damage in the eastern and southern divisions was $318,626, including $30,000 for roUing stock. Los Angeles cfc San Diego Beach Railway Co. — ^This road is within the city limits of San Diego. The damage included a trestle bridge 872 feet long and 2,700 yards of fill. The cost of the repair work was $14,000. Service was partly interrupted from January 11 to Feb- ruary 29, and whoUy from January 29 to February 11. San Diego <& Arizona Railway Co. — ^The damage to this road resulted from the failure of the Lower Otay dam and the break in the Sweetwater dam. The cost of replacement and repairs to grade, track, culverts, and bridges was estimated at approximately $55,000. HIGHWAYS AND BRIDGES. San Diego County. — Practically all important bridges in the county were washed out or became useless on account of changes in the channels of the streams. (See PI. IX.) AU roads were badly washed and some sections will require relocation when permanent repairs are made. Slides were numerous in the mountain districts, and aU travel stopped until temporary repairs could be made. The estimated dam- age to coimty highways was $370,000 and to bridges, $225,000. The State highway to San Diego was closed until the middle of March. Several bridges or their approaches, including those across Santa Margarita Creek (PL VII, B), San Luis Rey River (700-foot rein- forced-concrete arch bridge, PI. VIII, A), and San Dieguito River, U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 428 PLATE VMI A. VIEW UP SAN LUIS REY RIVER FROM MOUTH, AFTER FLOOD OF JANUARY, 1916. Showing damage to Atchison, Topeka & Santa Fe Railway and State highway bridges. B. DEBRIS ON BEACH AT OCEANSIDE AND DELTA BUILT UP BY SAN LUIS REY RIVER, AFTER FLOOD OF JANUARY, 1916. U. 8. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 426 PLATE IX A. HIGHWAY BRIDGE ACROSS SAN LUIS REY RIVER AT PALA, BEFORE FLOOD OF JANUARY, 1916. B. WRECK OF HIGHWAY BRIDGE ACROSS SAN LUIS REY RIVER AT PALA, AFTER FLOOD OF JANUARY, 1916. DAMAGE DUP: TO FLOOD. 33 were destroyed. Except for slight damage to shoulders and a few culverts, the concrete roadway was not mjured. The damage to State highway, including repairs made during the storms, was about $57,350. Orange County. — ^Almost the entire mileage of mountain roads will have to be rebuilt, as the grades were badly washed or buried by slides. The other graded and oiled roads were slightly damaged by deposits of debris and occasional washouts. The injury caused by undermining and shoulder cutting of paved highway was nominal. The loss of bridges was not considered, as they were old wooden structures which should have been replaced. The total damage was about $45,000. In addition, the State highway loss was approxi- mately $36,500, including repairs made during the storms. Riverside County. — ^The damage to 15 bridges, including 4 across Santa Ana River, was about $78,100. Several roads were badly washed out and the loss was approxunately $32,000. The injury to State highway, including repairs made during the storms, was about $18,500. San Bernardino County. — Nearly 40 bridges, including 3 across Santa Ana River, were washed out or damaged. The cost of replace- ment and repairs was about $67,524. The roads in every section of the county were seriously damaged. On Turner Avenue, Cuca- monga, the entire street was washed out from 4 to 12 feet in depth for a distance of 4J miles. Cajon and Mill Creek roads were badly washed and required extensive repairs. The damage to roads and culverts was about $80,656. The injury to State highways, including repairs made during the storms, was about $6,950. Los Angeles County. — ^The estimated damage to roads and bridges was $228,388. In addition, the. State highway loss, including repairs made during the storms, was about $26,250. A slide in section B, route 4, made it necessary to relocate the road. TELEGRAPH AND TELEPHONE LINES. ^Yestem Union Telegraph Co. — Practically all through lines were damaged by washouts at the principal stream crossings. Service was inteiTupted four days at the San Gabriel crossing, and the San Diego line closed for approximately a week. The total damage was about $23,500. Postal Telegraphs Cable Co. — The main lines to San Francisco, Saji Diego, and the East were damaged and service internipted. Tlie Los Angeles-San Diego line was washed out at practically every river crossing and at numerous other points. Service between Los Angeles and San Diego was stopped for nearly a week, and the other lines were closed from one to three days. The total cost of repairs was about $5,000. 106922°— 18— wsp 426 3 34 SOUTHERN CALIFORNIA FLOODS OF JANUARY, 1916. Pacific Tele/phone <& Telegraph Co. — ^The cost of reconstructing exchange lines, various sections of toll lines, and river crossings, either destroyed or rendered unsafe, was $97,600. Service, particu- larly over toll lines, was more or less interrupted for a period of approximately 606 hours. MISCELLAN20TJS DAMAGES. San Diego Consolidated Gas <& Electric Co. — ^The transmission lines and distribution system along San Diego River were washed out from El ^lonte to False Bay. There were also extensive washouts along Sweetwater River at Jamacho and from Sweetwater dam to San Diego Bay, on Otay River from Otay dam to San Diego Bay, and along Tia Juana River from Tia Juana to the Pacific Ocean. The principal damage was the loss of wood pole lines, copper wire, trans- formers, and miscellaneous electric-line material. The service in San Diego and immediate vicinity was not seriously interrupted. The lines to the more important towns were reestabhshed within two weeks, but some of the remote farming districts were without electric service for six weeks or more. The total damage to the gas and electric departments, corrected for value of salvaged material, was $70,527. Western Salt Co. — ^The losses consisted of 170 acres of salt groimd (which was covered with a deep deposit of silt), 2,500 tons of salt, a large quantity of brine in the ponds, and injury to machinery. The total damage was given as $85,500. Fenton-Sumption-Barnes Co. — This company operates a gravel-wash- ing plant in Otay Valley, about a mile from San Diego Bay. This plant was a complete loss, for after the flood there was not an indica- tion on the surface to show its location. The value of this equipment was $35,000. In addition, the soil was entirely removed from 100 acres of bottom land which had been purchased for about $450 per acre. The business loss was complete from January 27 to May 1. Indian reservations. — There was considerable damage to irrigation systems, buildings, and other improvements. In San Diego County the loss was approximately $38,000 and in Riverside County about $9,000. Los Angeles Harbor. — ^About 2,030,000 yards of silt was deposited in the channels during the flood. These deposits did not reach the outer harbor or even the main turning basin and main entrance chan- nel to an extent sufficient to interfere with commerce or require imme- diate dredging. At the extreme head of the harbor a channel reopened by a private corporation was filled with silt. There was also considerable silting in the East Basin chamiel. Long Beach Harbor. — Navigation was greatly inconvenienced by very heavy silting in the different channels and basins. The total COMPARISON WITH PREVIOUS FLOODS. 35 deposit of silt was about 1,000,000 yards. The indirect damage to the various industries in the harbor district was probably much greater than the expenditures which will be necessary for dredging. United States Geological Survey. — At the time of the flood the Survey was maintaining 23 river-measurement stations in the region covered by this report. AM these stations were seriously damaged. Tlio following equipment was lost : Six water-stage recorders, including wells and shelters; 17 staff gages; 10 cars and cables; and 8 concrete controls. In reequipping the stations it was found necessary, on account of great changes in the stream channels, to relocate two stations and abandon six. The total damage to equipment was about $2,600. COMPARISON OF FLOOD OF 1916 WITH PREVIOUS FLOODS IN SOUTHERN CALIFORNIA. BASIS OF COMPARISOir. To determine whether the flood of 1916 was more or less severe than previous floods in southern California, a search was made of the early records, and many old residents of the country were interviewed. The results of this work are summarized in the following pages. Of par- ticular interest is the record of wet and dry years, compiled by Mr. A. Campbell, who has lived in San Diego County since 1869. Information as to conditions in most of the years prior to 1840 was taken from records of the Mission Fathers. 1770 Drought. 1786 Copious rainfall. 1787 Rainfall insufficient; crops short. 1791 Extremely dry; no rain for whole year. 1794 Rainfall insufficient; crops short. 1795 Very dry. 1811 Flood year. 1815 Flood year. 1819 Short in rain and crops. 1825 Great flood changed course of Santa Ana River. 18261 1827 1 Dry years (Gen. Vallejos.) 1828] 1832 Short in rain and crops. 1840-41 Dryest year ever known. 1841-42 Wettest year ever known. 1842^3 Very open and dry. 1843-44 \eYy dry; no grain grown in Sacramento Valley 1845 Drought. 1845-46... . Wet in north; dry in southern California; cattle starved. 1846-47 - . . . Considerable rain; crops good. 1848-49... .Most snowy winter known; rainfall moderate. 1849-50... .One of the wettest and most flood y winters. 1850-51... .Open; rainfall moderate. 1853 -Big floods and snow. 1850-1856. .Flood and good years. 1856-57... . Dryest in 20 years. 1857-1862. .Medium rainfalls. 1862-63... .Dry years. 1863-1869. -All good wet years. 1869 . A very exceptional year. In October the thermometer registered 110°, and a rain- fall in December is esti- mated at 12 inches in 24 hours. 1869-70... . Dry season. 1870-71... .Dry season. 1872-74... . Fairly wet seasons. 1875-76... • Good rainfall. 36 SOUTHERN CALIFORNIA FLOODS OF JANUARY, 1916. 1876-77 Dry season. 1895-6-7 . ^. Three good wet years. 1877-1882 . .Good seasons. 1897-1900. .Three dry years. 1882-83 Dry years. 1901-1910 . . Fairly good wet years. 1883-84 Wettest winter known. 1910-1913. .Dry years at end of season. 188^1893 . .Series of good years. 1912-13 Dry year. 1893-94- . . -Short rainfall. The following additional information was obtained from ''A history of California floods and droughts," by J. M. Guinn: 1822. A flood covered the lowlands and rose to a greater height than ever before known. 1851-52. A severe flood year in southern California. At Old Fort Miller on head- waters of San Joaquin River, Dr. W. T. Edgar, surgeon of the post, observed a rain- fall of 46 inches during January and February, 1852. 1862. Santa Ana River at Anaheim ran 4 feet deep and spread in an unbroken sheet to Coyote Hills, 3 miles beyond. It rained 30 days in succession, beginning Decem- ber 24, 1861. FLOODS OW TIA JTTANA RIVER. Information concerning early floods on Tia Jiiana River was also furnished by Mr. Campbell, who considers the flood of 1884 the greatest in total run-off that has occurred during this time. The peak of that flood, however, was not so great as the peaks of the floods of 1891 and 1916, the only years in which, since 1869, water from Tia Juana River overflowed into the Otay drainage basin. In February, 1891, snow was above the fences at Mr. Campbell's ranch in Laguna Mountain divide, and one drift was 21 feet deep. This snow melted during a five days' rain. The lower Tia Juana Valley was flooded about as much in 1891, when the large hotel at Hot Springs, Mexico, was washed away, as in 1916. In comparing these floods the effect of storage at Morena reservoir in 1916 should be considered. SWEETWATER RIVER. Mr. C. H. EUis, sr., who has lived near Descanso for 35 years, states that the floods of 1884 and 1916 were the largest on Sweet- water River within that period. At the site of the Geological Survey gaging station the water rose 3 to 4 feet higher in 1916 than in 1884. In 1916 the channel was wider and at least 2 feet deeper than in 1884. It is his opinion that the flood of 1916 was approximately double that of 1884. The information presented in the following table was taken from a copy of the diary of the late WiUiam S. Gregg, Dehesa, Cal. : COMPARISON WITH PREVIOUS FLOODS. Record of flood of 1884. 37 Date. Rain- fall. Remarks. Date. Rain- fall. Remarks. 1884. Inches. 1884. Inches. Feb. 2- 3 2 River came with flood Feb. Mar. 27 1 3. (Total rainfall, Octolser 28 li to date, 10 inches.) 29 1 5 ^ 30-31 River rose a little. 6 2 Apr. 10 li 7 i 12-13 ]■ 10-11 1 River rising. 16 (") 15 li Cows over the river, can't 28 i get back. 29 16 li River higher than for 20 May 1 i 17-18 2i years. River higher. Over road to San Diego in two places. 15 18 li Cloudburst up by Harbin- son's. 25 Cattle, horses, etc., turned 19 1 Last night. over river. 20 June 1 U River high. Total rainfall for season, 34f Mar. 3- 6 2 inches. 7 i 1895. 10 1 Jan. 16 Sweetwater River very high. 14-15 higher than for 32 years. 15 f Great flood on. Farm cov- 23 ered with water from hill to 26 hill Jan. 17. o Showers. It is of interest to note that Mr. Gregg considered the flood of 1895 greater than that of 1884. The record ^ at Sweetwater reservoir shows that the total run-off of Sweetwater River for the year ending June 30, 1895, was 73,412 acre-feet; the record of J. F. Covert, chief engineer, Sweetwater Water Co., shows that the run-off at Sweetwater reservoir for January 16 to 31, 1916, was 111,000 acre- feet. (See pp. 48-49.) Mr. Covert gives the total run-off from Oc- tober, 1915, to September, 1916, as 160,580 acre-feet. SAN DIEGO RIVER. The highest known discharge into Cuyamaca reservoir, stated in terms of maximum rate of inflow for 24 hours^ is as fo flows: Second-feet. 1895, January 17 1, G30 1906, March 1, 120 1916, January 27 2, 400 The following information was obtained in an interview with Mrs. Martha Swycaffer, who came to San Diego in 1854. Mrs. Swycaffer states that the flood of 1862 was greater than any other within her time. The rain began in the fafl of 1861 and the rainy season lasted until June, 1862. Beginning Christmas Day, a rain set in which lasted for at least six weeks, during which time there was not sunshine enough to dry a handkerchief. At about the end of this storm the rain set in more heavfly, causing the big flood. Before the peak the river occupied two channels, one on each side of the Swycaffers' home but a considerable distance from it. The 1 McGlashan, II. D., and Doan, If. J., Water resources of California, part 3: V. S. (leol. Survey Water- Siipply Paper 300, p. 493. 1913. 38 SOUTFTRRN CALIFORNIA FLOODS OF JANUARY, 1916. SwycafFer liouse was a two-story brick-veneered building. As the flood increased it was necessary to move into the upper story of the building, all the lower doors and windows being left open to ease the force of the flood. The Swycaffer house was the only one in the San Diego River bottom that stood, and all inhabitants in the vicinity sought refuge in the second story. The refugees were rescued from the second-story window in a surf boat manned by sailors, and Mi-s. Swycaffer and thi'ee babies were then sheltered in an adobe house in Old Town. During the night a dike built for the protection of Old Town was overtopped, and her refuge was again flooded. The family was carried to the Old Palms and placed under the one which was out of water; the ground at the other was flooded. The flood of 1862 was of long duration for a southern California stream, as it maintained approximately its peak height for 24 hours. Mrs. Swycaffer does not consider the flood of 1884 as large as that of 1916. In her opinion the flood of 1916 was next m magnitude to that of 1862. Mrs. Swycaffer was familiar with, what is now the Foster and Lake- side country. At Lakeside the high water reached to the old adobe ranch house, or an elevation of the present Lakeside store. At Foster the flood height reached nearly to the top of an inmiense oak, which was removed when the railway was budt. This flood would have washed out all the present buddings in Foster. Previous to 1862 the present site of San Diego (New Town) was on rounded hifls; the draws and guflies now existing were begun m 1862. When Mrs. Swycaffer first visited the Warner Hot Springs the springs broke out on a graduaUy sloping plam; the flood of 1862 made the topography as it is to-day. Mrs. Swycaffer knew everyone in Old Town in 1862, and no flood within the memory of any or in the traditions of the place was com- parable with it. SAN LtriS REY RIVER. In the early days houses and ranch buildings were built on high ground, and the bottom lands along the river channels were used only as pastures. As the number of settlers increased the agricul- tural lands became more valuble, and at the time of the floods of 1916 the bottom lands had reached a high state of cultivation and budd- ings were erected where they would be most convenient without any particular thought of the damage from excessive floods. Mr. P. F. Hubbard, who has lived near San Luis Rey River since 1873, considers that the only flood in his time that is comparable with that of 1916 occurred in 1884. The flood of 1916 was 2 feet higher at COMPARISON WITH PREVIOUS FLOODS. 39 his well and the channel was wider than in 1884. The bottom lands m 1884 were covered with brush and trees and the channel did not cut much. As there were no cultivated fields or builduigs m the path of the flood the damage was slight. Mr. Edward Canteriui, who has lived in San Luis Rey Valley since 1884, states that there was more rain in 1884 than in 1916 and the flood was of longer duration, but he does not consider that the maxi- mum discharge was as great as m 1916. The river did not have a well-defined chaimel prior to 1891. Immediately after the flood of January 27, 1916, Father Doyle, of the Pala Mission, San Diego County, talked with an old Indian who had lived along San Luis Rey River for many years. The Indian stated that this flood was greater than that of 1862. The old mission ditch at Pala, constructed more than 100 years ago, was washed out in a number of places by the flood of 1916, but previous floods had not injured it. Father Doyle considers the flood of 1916 the greatest which has occurred since the valley has been settled. The flood of 1862 he places second in size, and that of 1884, third. Edward R. Bowen, in a paper on the San Luis Re}^ floods of Jan- uary, 1916,' says: The entire San Liiis Rey Valley was inundated, the stream extending from hill to hill — a distance of probably 1^ miles — and covering an area of over 1,000 acres. The drift along the coimty road on the south side of the valley indicated a 6-foot depth of water at that point. * * * It is probable that the enormous quantities of silt and debris carried by the stream in the first flood, together with that carried by the subsequent one, so built up and raised the old channel of the river that it was at a greater elevation than the adjacent valley lands. When the second flood came down this channel, its banks were overtopped and a new channel formed, cutting across the valley in a northeast to southwest direction, taking a long sweep to the westward at about the middle of the valley and retui-ning to an old course near the narrows, * * * All farms in the valleys of the lower river were completely destroyed and three people were drowned. The entire valley is covered "vsith deposit of sand and silt to an average depth of at least 3 feet, and in many places as much as 6 feet. Conditions along the upper river are not so bad. The valleys are more constricted and the stream better confined, although all crops along the bottom lands have been ruined. [See PI. IV, B, p. 28.] TEMECTTLA CREEK. Mr. F. L. Femold, of Temecula, Riverside County, reports that the flood of 1891 in Temecula Canyon rose to a height of about 2 feet on the trunk of a large oak tree on the bank at the ford. A neighbor, who was with hini, said that this height was very close to the peak of the flood of 1884. This tree was washed out during the flood of January, 1916, after the water had risen about 12 feet on the trunk. The canyon at this point is in solid rock and conditions would be the same for all floods. 1 Eng. News, vol. 75, No. 8, p. 385, Feb. 24, 1916. 40 SOUTHERN CALIFORNIA FLOODS OF JANUARY, 191C. LOS ANGELES AND SAN GABRIEL RIVERS.i There were heavy floods on Los Angeles and San Gabriel rivers in 1825, 1833, 1862, 1867, 1884 (2), 1886, 1889 (2), 1890, 1911, and 1914, and it is said that serious floods occurred also in 1842, 1852, and 1874. From the testimony in the case of Andres Daneri v. Southern California Raih'oad Co., superior court of Los Angeles County, in 1897, the largest floods occurred in 1825 and 1833 and the next largest flood was in 1862. It seems to be generally agreed that the greatest flood since 1862 occurred in 1889. The flood table prepared by the United States Weather Bureau, for the period 1878 to 1914, shows that 41 floods occurred in the vicinity of Los Angeles during tliis period. The flood of 1909 in Los Angeles River was observed by H. Haw- good and William MulhoUand (then superintendent of the Los Angeles City Water Co.). From the measured cross-section of the channel at the Southen Pacific Co's. crossing, on its main line east, and from the slope of the w^ater surface, together with personal obser- vations of the river at time of flood, Mr. Hawgood estimated that the maximiun discharge was in excess of 35,000 second-feet. The details of the computation are not now available. The section observed by Mr. MulhoUand was about 1,200 feet north of Buena Vista bridge. Here the surface velocity, as observed from debris floating down the stream, was 14 to 16 miles per hour. The depth of water was given as 9 feet and the width as 300 feet. The dis- charge, as computed from these data by Mr. Hawgood, was approxi- mately 45,000 second-feet. FLOOD RUN-OFF IN JANUARY, 1916. COLLECTION OF RECORDS. At the beginning of the first storm on January 17, Mr. Ebert reached San Gabriel River near Azusa, and on January 17 and 18 he made float measurements just below the gage; the cable was not accessible, as the highway was washed out above the mouth of the canyon. January 20 he attempted to reach Santa Ana River near Mentone, but foimd the highway impassable east of Highland. The highway west of Azusa was also closed on account of the damage to the San Gabriel bridge. The Pacific Electric Railway was opened from Azusa to Los Angeles January 21. Mr. Ebert left Los Angeles for San Diego by the inland route January 24 and reached Escondido the night of January 26. The heavy rainfall during that night destroyed the highways in all directions, and he was detained there by the condition of the roads 1 Abstracted from reports of the Board of Engineers Flod^ Control to the Board of Supervisors, Los Angeles County, Cal., submitted July 27, 1915, pp. 144-146 and 172-174. FLOOD RUN-OFF. 41 until February 5, when his automobile was drawn across San Die- guito River at Bernardo by a four-hoi-se team, and he reached Lake- side that night by way of Poway grade, Miramar ranch, and Pacific Beach. A measurement could not be made on San Diego River at Lakeside, as the cable had been washed out and the river was flowing in a wide channel to the right of the highway bridge. The following day he visited Sweetwater River near Descanso, but on account of the damage to highways he was unable to reach any other stations in this territory or those on Santa Ysabel Creek and upper San Luis Rey River. He made the return trip from San Diego by boat February 9. In March, 1916, Mr. McGlashan and Mr. Ebert made an extensive trip through the region covered by this report to obtain available flood data and to coUect records obtained by private parties. They visited the river-measurement stations that were accessible at this time, and also a number of streams on which no stations were being maintained. The flood marks were still very distinct, so that it was possible to make numerous measurements of slope and of cross sections of river channels at maximum stage, and to obtain other data necessary for the computation of flood flow. The results were computed by Kutter's formula, after carefully selecting values of n. The base data, as well as the computed records, are here published, to enable any engineer engaged in a detailed study of the run-off to make independent computations of the flow. TIA JTJANA RIVER BASIN. GENERAL FEATURES. Tia Juana River discharges into the Pacific Ocean below San Diego Ba}^ near the ^Mexican boundary. Its principal tributary, Cottonwood Creek, rises in the Laguna Mountains of the Coast Range and flows southwestward about 32 miles to its junction with. Tia Juana River at the Mexican boundary, about 22 miles east of the coast line. The total drainage area of Cottonwood Creek above its junction with Tia Juana River is approximately 340 square mdes. It hes south of the Sweetwater and Otay River basins, and is the most southerly stream in San Diego County. Pine Valley Creek, wliich joins it 20 miles below its source, is its only important tributary. The topography of the basin of Cottonwood Creek is rough tlirough- out, although some valley areas are found above the 3,000-foot contour. Below tlfis elevation the stream flows through a deep, narrow canyon, broken only by a short stretch of open country with comparatively fight grade at the junction of Pine Valley Creek. Altitudes range from 600 feet above sea level, where the creek joins Tia Juana River, to 5,000 feet on the Laguna Mountains. 42 SOUTHERN CALIFORNIA FLOODS OF JANUARY, 1916. The Cottonwood basin is poorly forested. The timber consists of scattered oaks, cottonwoods, and alders, which are restricted almost entirely to the small valleys along the stream and to the higher elevations. The mountain slopes are fairly well covered with brush. The mean annual rainfall ranges fron 8 to 10 inches along the foothills and from 20 to 30 inches in the mountains. COTTONWOOD CREEK AT MORENA RESERVOIR, CAI..» Location. — In the SW. \ sec. 14, T. 17 S., R- 4 E., three-fourths mile north of Morena Butte, 1| miles above mouth of Hauser Creek, and 8^ miles upstream from Barrett dam, San Diego County. Draikage area. — 119.5 square miles (reported by George Cromwell). Elevation, — About 3,000 feet above sea level. Discharge. — Computed from gage-height record showing storage in reservoir, cor- rected for waste through spillways and outlet tower. Spillway.— Consists of 12 openings, each Sh feet in length, controlled by independent radial gates. All gates were open until 7 a. m., January 29, when 11 were closed. At 11 a. m., January 29, 6 gates were opened and at 5 p. m. the remainder were opened. January 30 at 7 a. m., all gates were closed. Two gates were opened at 7 a. m., January 31 and the remainder at 6 p. m. Average depth of water in spillway was as follows: January 28, 4 feet ; January 29, 3.25 feet; January 31, 3 feet. Considerable drift collected at the spillway which interfered with the operation of the gates. Maximum capacity of spillway, 5,380 second-feet and of outlet tower, 483 second-feet. Outlet tower. — There are 5 valves in the tower. Number 4, at 99.5 feet, was opened January 28 at 1.30 a. m. and closed January 29 at 6.30 a. m. Xo other valves were opened during the month. Maximum discharge in January, 1916. — January 27, 7 a. m. to 4 p. m., 8,785 second-feet; 4 p. m. to 6 p. m., 15,356 second-feet; 6 p. m. to 12 p. m., 13,344 second-feet. January 28, 12 a. m. to 7 a. m., 3,157 second-feet. The following table contains data furnished by George Cromwell, city engineer, San Diego, Cal. : 1 O'Shaughnessy, M. M., Construction of the Morena rock-fill dam, San Diego County, Cal.: Am. Soc. Civil Eng. Trans., vol. 75, p. 27, 1913. FLOOD RI'X-OFF. 43 Gaqchright and discharge of Cottonwood Creek at Morena reservoir, Cal.,for Januan^. 1016. Gage height (feet). Storage (milUon gallons). Waste. Run-off from drainage basin. Day (7 a. in.) Million gallons. Acre-feet. Million gallons. Acre-feet. Second- feet. j.^n 1 118.68 118.70 118.71 118.73 118.77 118.79 118.82 118.^ 118.89 118.92 119.11 119.17 ■ 119.19 119.21 119.72 120.01 124. 19 130.00 134.20 135. 21 135.80 136.17 136.51 136.80 137. 15 137.64 138.40 150.50 149.50 149.00 149.50 148.50 5, 189 5,193 5,195 5,199 5,208 5,212 5,217 5,221 5,231 5,237 5,275 5,287 5,291 5,295 5,39S 5,475 6,3*^5 7,8^ 9,102 9,420 9,634 9,754 9,863 9,9.56 10,071 10,240 10,511 15,450 15,000 14,775 15,000 14,552 4 12.3 6.1 12.3 27.6 12.3 15.4 12.3 30.7 18.4 116.7 36.0 12.3 12.3 416.8 236.4 2,793.7 4,-509.8 3,831.4 976.3 656.9 368.4 334.6 285.5 353.1 518.8 831.9 17,520.5 3,923.5 2,072.3 690.7 647.7 6.2 2 2 4 9 4 3.1 3 6.2 4 13.9 5 6.2 6 5 4 10 6 38 12 4 4 103 77 910 7.7 7 6.2 8 . -- ! 15.5 9 j 9.3 10 . . -. 1 58.8 11 1 18.6 12 . . .. 1 6.2 13 i 6.2 14 :;:: l 1.59. 4 15 1 119.2 16 :;.: ; 1,408.6 17 - . -. :-:-|--::::;; 1,409 1,248 318 214 120 109 93 115 2, 273. 18 1,931.0 19 492.3 20 331.7 21 185.7 22 168.7 23 1 143.9 24 178.2 25., .. 1 169 271 5,707 1,278 675 225 211 261.6 26 i 419.5 27 28. 768 1,728 900 2,357.6 5, .304. 9 2,76.3.0 8,8^.3 1, 978. 3 29 : 1,M4.8 30 348.2 31. 659 326.6 Feb. 1 Total run-off for monthj^^^p^^^J^ i^-^j^- - ;^-^-, acre-feet 41, 200 e area 6. 43 OTAY RIVER BASIN. GENERAL FEATTJRES. Otay River drains the region between Sweetwater basin on the north and Tia Juana on the east and south. Above Lower Otay dani it has a drainage area of 98.6 square miles. The general course of the stream is southwest, and it enters San Diego Bay at the extreme southern end, about 4 miles north of the International boundary. Above Lower Otay reservoir the stream is known as Jamul Creek, to which Dulzura Creek is tributary. The natural run-off from this area is increased by the water diverted from Cottonwood Creek through Dulzura conduit, into Dulzura Creek. Tlie dramage area of Jamul Creek is mountainous and the slopes are very steep. The highest point is Lyons Peak; elevation, 3,755 feet. The forest cover is mainly brush, except in the vicinity of the stream chamiels. The mean annual precipitation ranges approximately from 8 to 20 inches. 44 SOUTHERK' CALIFORNIA FLOODS OF JANUARY, 1016. OTAY RIVER AT LOWER OTAY RESERVOIR,' NEAR OTAY, CAL. Location. — The dam was in the extreme northwest corner of sec. 18, T. 18 S., R. 1 E., at the head of the canyon above Otay Valley, about 16 miles southeast of San Diego and 8 miles east of Otay, San Diego County. Drainage area. — 98.6 square miles (measured on topographic map; includes 12.7 square miles, tributary to Upper Otay reservoir) Elevation. — Top of dam was about 480 feet above sea level. Gage. — Vertical staff fastened to outlet tower (PI. II, A). Zero of gage, 346.65 feet above sea level, U. S. Geological Survey datum. The gage-height record for January 22-27, 1910, given in the storage table for the reservoir, was obtained from employees at the reservoir a short time after the dam failed. The record January 15-21 was published in the Engineering Record for February 12, 1916. Spillway. — Built of concrete at left of dam; width on bottom, 37.9 feet; width at top, 41.5 feet; depth, 8 feet; uniform slope, 0.00365. Floor of spillway is 123.3 feet above zero of gage. It is stated that the spillway has the same dimensions through- out its length, and hence did not admit sufficient water to fill the channel for its entire length. The discharge of the spillway at the time the dam failed was 4,700 second-feet according to George Cromwell, city engineer.^ John L. Bacon, former assistant city manager, estimated the maximum discharge of the spillway as 2,000,000,000 gallons daily, or 3,100 second-feet.^ Outlet tunnel . — There was no pro\asion for blow-off from the reservoir except through the outlet tunnel, which connected with the pipe line to San Diego. At the lower end of the tunnel there was a Y connection with a 36-inch blow-off valve, which was opened at noon January 27, 1916. The maximum capacity through this blow-off was 330 second-feet, according to George Cromwell, city engineer.* Maximum discharge in January, 1916. — The maximum gage height in the reservoir was reported as 134.0 feet at 5.05 p.m., January 27, at which time the dam failed. From the table showing storage in reservoir, the rate of inflow from 4.25 p. m. to 5.05 p. m. was 32,700 second-feet. If the maximum discharge of the spillway as given by the city engineer is added, the total was 37,400 second-feet, or 379 second-feet per square mile of drainage area. Data concerning cross sections and slope were obtained on Jamul Creek (see p. 45) just above effect of backwater from the reservoir. The maximum dis- charge at this point was computed as 18,100 second-feet, or 259 second-feet per square mile of drainage area. If this same rate of run-off is assumed for the 12.7 square miles of drainage area above Upper Otay dam, the maximum flow over the dam and through si:>illway did not exceed 3,300 second-feet. George Cromwell, city engineer,* stated that the run-off into the Lower Otay reservoir was 23,500 second-feet for a period of one hour prior to the failure of the dam . This rate would allow a run-off from the drainage area directly tributary to the reservoir, exclusive of Upper Otay reservoir and Jamul Creek, of 2,100 second- feet, or 130 second-feet per square mile, provided the crest discharges all reached Lower Otay reservoir at the same time. The maximum discharge computed from the reservoir record exceeds that pub- lished by Mr. Campbell by nearly 60 per cent. The run-off per square mile com- puted from the reservoir record is more than 50 per cent greater than that reported for Sweetwater River at Sweetwater dam. See table of crest discharge (p. 23) for maximum discharge for other streams in this region. The mean rain- fall, computed for drainage area^bove Lower Otay dam, was 19.2 inches; that for Sweetwater River above Sweetwater dam was 21.8 inches. (See table, p. 11.) 1 See pp. 25-26 for description of failure of dam on Jan. 27, 1916. 3 Idem, Feb. 3, 1916, pp. 23&-239. « Eng. News, Apr. 13, 1916, p. 717. * Idem, Apr. 13, 1916, p. 718. FLOOD RUN-OFF. 45 Authority. — Data for this station were obtained in the field, from the publications cited, and from other reliable sources. Data collected by the city of San Diego were withheld because of pending litigation. Storage in Lower Otay reservoir for January, 1916. 9 Time. Gage height (feet). Available storage. Increase in .slorage.o Date. Million .„_,_, gallons. Acre-feet. Acre-feet. Second- feet. Jan. 15 84.0 101.0 111.0 118.7 122.8 123.3 123.6 123.8 123.95 124.0 124.9 127.9 130.0 131.3 132.3 134.0 3,610 6,230 8,350 10,200 11,340 11,490 11,580 11,640 11,680 11,700 11,970 12,950 13,650 14,080 14,440 15,030 11,100 19,100 25,600 31,300 34,800 35,300 35,600 35,700 35,900 35,900 36,700 39,800 41,900 43,200 44,300 46,100 17 8,000 6,500 5,700 3,500 500 300 100 200 800 3,100 2,100 1,300 1,100 1,800 2,020 3 280 Jg 19 2,870 21 882 22 7a. m 7a. m 7a. m 7a. m 7 a. m 7 a. m Noon 3p.m 4p.m 4.25 p.m.. 5.05 p. m.. 252 23 151 24 50 25 101 26 27 ... 403 7,500 8,470 15, 700 31,900 32,700 a Discharge through spillway not included. Note. — The available storage in million gallons, given in the above table, was taken from a capacity curve compiled in the office of the city engineer, San Diego. Gage-height record, Jan. 15-21^ was published in Engineering Record for Feb. 12, 1916; Jan. 22-27 was obtained from employees of the city of San Diego at the dam a short time after the failure. JAMUL CREEK NEAR OTAY, CAL. Location. — In sec. 4, T. 18 S., R. 1 E., about 500 feet above highway crossing above Harvey ranch and well above backwater from Lower Otay reservoir at high- water elevation, and about 11 miles east of Otay, San Diego County. Drainage area. — 69.8 square miles (measured on topographic map). Elevation. — About 500 feet above sea level. Channel. — ComxK)sed of sand, gravel, and boulders; practically straight for the sec- tion covered by slope data, but curves to the left just below point where lower cross section was taken. Banks high and practically clean aft^r flood (PI. X, B). Channel apparently fairly permanent. Maximum discharge in January, 1916.— Measurements of slope and of two cross sections were made March 17, 1916. Slope of water surface that day was deter- mined for a distance of 935 feet. The determination of high- water slope checked fairly well with that of the slope of the water surface March 17, but could not be ascertained so accurately on account of the roughness of the banks. The maximum discharge has been computed as follows: Mean width, 158 feet; mean area, 1,360 square feet; mean wet perimeter, 164 feet; mean hydraulic radius, 8.3; present slope of water surface, 0.0071 (for 935 feet) March 17, 1916. If the value of 7iin Kutter's*lormula is assumed as 0.04, the discharge is 18, 100 second-feet, or 259 second-feet per square mile of drainage area. SWEETWATER RIVER BASIN. GENERAL FEATURES. Sweetwater River rises in the south and east slope of the Cuyamaca Mountains of the Coast Range, flows nearly due south for 15 miles, then turns to the west and southwest and discharges into San Diego Bay south of National City. Its length is 45 miles, and its area 46 SOUTHERN CALIFORNIA FLOODS OF JANUARY, 1916. comprises approximately 215 square miles, the greater part of which is in mountainous country. The basin is extremely narrow. It lies directly south of San Diego River and north of the Otay River and Cottonwood Creek basins. Tlie topography is not so rougft as that of San Diego River basin, although the mountains and foothills extend within 3 or 4 miles of the shore Une of San Diego Bay, and the valle}^ and mesa lands are not so extensive a^ along San Diego River. The basin is poorly forested. The tunber is confined almost to the immediate valleys of the streams and to the higher mountain areas. Tlie moun- tain slopes have a fairly good covering of brush, but the lower foot- hills are almost bare, supporting only a sparse growth of low brush. The mean annual rainfall varies from 10 to 15 inches along the foothill belt and from 20 to 45 inches in the mountains. A considerable area l3^ing between San Diego Bay and the footliills south from National City to the Mexican boundary is under a high state of cultivation. The greater part of this land is irrigated by water taken from Sweetwater River. SWEETWATER RIVER NEAR DESCANSO, CAL. Location.— In the SE. i sec. 25,, T. 15 S., R. 3 E., at Ellis ranch, 2 miles below mouth of Guatay Creek and about 1^ miles below Descanso, San Diego County. Drainage area. — 43. 7 miles (measured on topographic and military-survey maps). Elevation. — About 3,300 feet aliove sea level. Records available. — November 21, 1905, to January*, 1916. Gage. — Staff in three sections on left bank at concrete control, a short distance below intake of Ellis ditch; destroyed by the flood of January, 1916. Installed at same datum and practically same location as pre^■ious gage. Discharge measurements. — Made from cable at gage or by wading. No measure- ments' were made during the flood of January, 1916. as the highways were im- passable. Channel and control. — Channel composed of sand, fine gravel, and boulders; shifting. Banks are high and not subject to overflow. A concrete control constructed October 11, 1914, across the channel opposite original gage was practically destroj-ed by the flood of Januar}-, 1916. Extremes of discharge. — 1905-1915: Maximum stage recorded, 9.25 feet at 5 p. m. March 24, 1906 (approximate discharge, computed from extension of rating curve, 3,000 second-feet): channel dry during a portion of the years 1910, 1911, and 1913. Maxim CM discharge in January. 1916. — No gage-height record after Januar}'' 23, when gage was washed out. Measurements of slope and two cross sections were made March 13, 1916, in the vicinity of the gaging station. The channel (PI. X, A), is practically straight for the section covered by slope data. Banks high and covered with brush and small trees. The maximum discharge has been computed from the mean of the two cross- sections, as follows: Mean area, 987 square feet: mean hj'drauUc radius, 6.0; slope of water surface, 0.0078 (for 875 feet) March 13. If the value of n in Kutter's formula is assumed as 0.045, the discharge is 9,870 second-feet, or 226 second-feet per square mile of drainage area. U. 8. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 426 PLATE X A. VIEW DOWNSTREAM ON SWEETWATER RIVER NEAR DESCANSO, AFTER FLOOD OF JANUARY, 1916. B. VIEW UPSTREAM ON JAMUL CREEK NEAR OTAY, AFTER FLOOD OF JANUARY, 1916. U. 8. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 426 PLATE XI A. VIEW UPSTREAM SHOWING CAPITAN GRANDE DAM SITE ON SAN DIEGO RIVER, AFTER FLOOD OF JANUARY, 1916. B. VIEW UPSTREAM ON SAN VICENTE CREEK AT FOSTER, AFTER FLOOD OF JANUARY, 1916. FLOOD BUN-OFF. 47 Accuracy. — Determinations of discharge Januaty 16 to 22, roughly approximate aa they are computed from an extension of the rating curve for 1914-15, which is unsupported by high-water measurements. It is assumed that the concrete control was not disturbed until the second rise, which occurred Januar>' 27. Gage height, in feet, and discharge, in second-feet, of Sweetwater River near Descaruo, Cal.ffor January, 1916. 9 a.m. 5 p. m. Date. height. Dis- charge. hefglft. Dis- charge. Jan 14 1.38 2.20 2.30 6.00 6.00 4.00 3.70 .3.50 3.50 21 137 159 2,500 2 500 822 666 570 570 1.38 2.20 4.40 6.00 4.70 3.80 3.50 3. .50 3.80 21 15 137 16 1,060 17 2 .500 18 1 290 19 716 20 570 21 570 22 716 Note.— For maximum discharge during January see description of station. No record Jan. 23 to 31, as gage was washed out. SWEETWATER RIVER NEAR DEHESA, CAL. Location.— In the NW. \ NW. I sec. 20, T. 16 S., R. 2 E., at Sloane ranch, 1,000 feet below mouth of Lawson Creek, about 3 miles southeast of Dehesa, San Diego County. Drainage area. — 112 square miles (measured on topogi-aphic and military-survey maps). Elevation. — About 900 feet above sea level. Records available. — December 4, 1913, to January, 1916. Gage. — Bristol water-stage recorder on left bank 5 feet above control; destroyed by flood of January, 1916. No gage-height record available for that month. Discharge measurements. — ^Made from cable 200 feet below concrete control or by wading; equipment destroyed by flood, January, 1916; no discharge measure- ments were made during that month. Channel and control. — Bed composed of shifting sand overKing solid rock. The concrete control, which extended to bed rock, was destroyed by the flood of January, 1916. Banks are high and not subject to overflow. , Extremes of discharge. — 1913-1915: Maximum stage recorded, 5.8 feet February 11, 1915 (approximate discharge computed from extension of rating curve, 1,750 second-feet); channel practically dry August 12, 1915, to end of year. Maximum discharge in January, 1916. — Mr. J. F. Covert, chief engineer, Sweet- water Water Co., measured cross sections and obtained slope data at this station. Determinations of maximum discharge for the flood of January, 1916, based on these data, were furnished by F. C. Finkle, consulting engineer, as follows: Mean area, 1,639 square feet; mean wet perimeter, 184 feet; mean hydraulic radius, 8.9; slope, .0047 ; assumed value of n in Kutter's formula, .03; coefficient c, 72.5; mean velocity, 14.82 feet per second; discharge, 24,295 second-feet or 217 second- feet per square mile of drainage area. SWEETWATER RIVER AT RUDOLPH RANCH, NEAR DEHESA, CAL. From measurements of cross sections and slope at the highway crossing near south line of sec. 14, T. 16 S., R. 1 E., San Diego Comity, made by J. F. Covert, chief engineer, Sweetwater Water Co., the 48 SOUTHERN CALIFORNIA FLOODS OF JANUARY, 1916. maxiinimi discharge for the flood of January, 1916, was computed and furnished by F. C. Finkle, consulting engineer, as follows: Mean area, 2,382 square feet; mean wet perimeter, 485 feet; mean hydraulic radius, 4.9; slope, 0.0045; assumed value of n in Kutter's formula, 0.025; coefl^cient c, 77.9; mean velocity, 11.56 feet per second; discharge, 27,530 second-feet or 204 second-feet per square mile (drainage area given as 135 square miles). SWEETWATER RIVER NEAR JAMACHO, CAL. Measurements of cross sections and slope made by J. F. Covert, chief engineer, Sweetwater Water Co., at Jamacho Canyon, San Diego County, were used by F. C. Finkle, consulting engineer, to compute the maximum discharge for the flood of Januar}^, 1916, with the folio whig results: Mean area, 3,006 square feet; mean wet perimeter, 410 feet; mean hydrauhc radius, 7.3; slope, 0.0057; assumed value of ti in Kutter's formula, 0.03; coefficient c, 70.2; mean velocity, 14.3 feet per second; discharge, 43,002 second-feet or 250 second-feet per square mile (draniage area given as 172 square miles). SWEETWATER RIVER AT SWEETWATER DAM, CAL. The foUowing table was prepared by J. F. Covert, chief engineer, Sweetwater Water Co., for court use. It is known as Exhibit L in the Neuman case and Exhibit J in the Suthff case. Sweetwater reservoir is on Sweetwater River about 6 J miles northeast of National City, San Diego County. The drainage area tributary to the reservoir is 181 square miles (measured on topographic and mihtary survey maps). FLOOD RUN-OFF. 49 Discharge, in second-feet, of Sweetwater River at Sweetwater dam, Cat., for Jan. 16 to 31, 1916. Date. Jan. 16 16-17 17 17 17 17 17 17 17-18 18 18 18 18 18 18 18-19 19 19-20 20 20-21 21 21-22 22 22 22-23 23 23-24 24 24-25 2.5-26 2&-27 27 27 27 27 27 27 27 27 27 27 27 27-28 28 29 30 31 Time. 8 a. m. to 5 p. m 5 p. m. to3 a. m 3 a. m. to8a. m 8 a. m. toll a. m 11 a. m. to 3.15 p. m.. 3.15 p.m. to 5.15 p. m. 5.15 p. m. to 9 p. m... 9p. m to 11 p. m 11 p. m. to3 a. m 3 a. m to5 a. m 5 a. m to8 a. m 8 a. m. to 12 m 12 m. to 5 p. m 5 p. m. to 8.30 p. m... 8.30p.m. to 10.30 p. m 10.30p. mto4.30a. m. 4.30 a. m. to5 p. m. .. 5 p. m. to6 a. m 6 a. m to 5 p. m 5 p. m to 7 a. m 7 a. m. to5p. m 5 p. m. to 5 a. m i 5 a. m. to8 a. m i 8 a. m. to5 p. m .5 p. m. to 8 a. m 8 a. m. to 5 p. m ' 5 p. m. to 7 a. m 7 a. m too p. m j 5 p. m. to7 a. m ' 7 a. m. to 7 a. m 7 a. m. to 4. .30 a. m... 4. .30 a. m. to7 a. m... 7 a. m. to 9 a. ra 9 a. m. to 11 a. m 11 a. m. to 11.45 a. m. 11.45 a. m. to 1 p. m. . 1 p. m to 2.20 p. m... 2.20 p.m. to 4.08 p.m. 4.08p. m, to4.30p. m. 4.30p. m.to5..30p. m. 5.30 p.m. to 6.30 p. m. 6.30 p. m. to9 p. m.. 9 p. m. to 8 a. m 8 a. m. to 5 p. m Accumu- lative run-off. 809 4,215 6,050 4,185 4,185 5,950 9,090 5, .580 6,130 6,130 1,740 2,. 500 2,500 1,488 802 - 689 -1,248 -1,186 -1,023 - 495 - 600 - 87 ■■■■339" 331 318 225 215.5 126.5 112.8 77.2 1,850 1,928 1,948 7,790 13,060 17,180 24,200 16,280 -2,550 -43,300 -31,050 -9,870 -.5,970 -1,288 - 481 - 369.5 Waste. Total discharge. Through blow-off. Spill- way. Over parapet. Through breaks. 1 809 ■ 4,215 6,0.'0 232 1 4,417 4,417 6,182 9,322 5,812 6,922 7,991 4,330 5,648 6,439 5,866 5,455 3,768 232 232 i 232 ! 232 1 232 560 1,629 2,. 358. 2 2,775.7 3,220 3,6.58 3,932 3,737.6 3,297.7 2,606.7 1,586.5 883 518.5 340.5 157.5 232 1 232 372 719 1 720 1 721 ::::::::::i:::::::::: 719 L. 716 2,766 2,135 l!274 714 711 709 1,097 706 625 181 434 181 ! 339 1 339 .:::::;;::..:::::: :::: 331 1 318 " "1 . 225 23.8 83.1 190.6 316 545 895 1,314 1,803 2,826 4,063 4,953.4 5, 460. 4 5,503 5,049 2,314 239 210 304 393 2,395 326 3,149 347 3,609 368 9,961 368 16,2.54 368 21,611 408 3,860 8,S30 9,oeo 4,420 33,421 448.5 449 444 434 8,181 33,008 70,487 59,902 2.5,050 14,570 5,6^19 4,022 2,640 38, COO ' 45,500 37,100 31,600 410 8 15,600 400 1 9,000 429 I 4,790 469 1 4,000 469 1 2,740 Mean daily dis- charge. 1,.530 5,870 5,900 2,770 1,4S ""707 ""'356 295 226 277 367 15,000 9,970 4,790 4,000 2.740 Total run-off for I. periods acre-feet HI ,000 depth in inches on drainage area 11. 55 Note.— Mean daily discharge, total discharge in acre-feet, and run-off in depth in inches computed by Engineers of United States Geological Survey. SAN DEEGO RIVER BASIN. GENERAL FEATURES. San Diego River rises in the Cuyamaca Mountains, on the western slope of the Coast Range, flows south westward, and discharges into Pacific Ocean through False Bay at the northern boundary of San Diego City. Its length is about 50 miles, half of wliich hes in the mountains above the town of Lakeside. The San Diego basin has an area of 434 square miles and lies directly south of the San Dieguito bas;in and north of the Sweetwater River basin. 106922°— 18— wsp 426 4 50 SOUTHERN CALIFORNIA FLOODS OF JANUARY^ 1916. The San Diego has several small tributaries, the most important being Coleman, Cedar, Boulder, South Fork, and Chocolate creeks, all of which enter from the east and south above Lakeside. San Vicente Creek, the only important tributary from the north, enters the river at Lakeside. The upper part of the basin above Lakeside is extremely rough and rugged, but below Lakeside numerous vallej^s and high mesa lands extend to the coast. Elevations throughout the basin range from 50 to 600 feet in the foothills and from 600 to 6,000 feet in the moun- tains. Cuyamaca Peak, the highest point in the basin, has an elevation of 6,028 feet. The formation is the loose granite that is typical of all river basins in San Diego County. The San Diego basin is poorly forested. The timber is confined almost entu'ely to the vaUey along the streams and to the higher mountain areas. The mountain slopes are fairly weU covered with brush, but the lower foothills are almost entirely bare, supporting only a scattered growth of low brush. The mean annual rainfall ranges from 10 to 15 inches along the foothill belt, and from 20 to 45 inches in the mountains. Irrigation is carried on extensively in the valleys and on the mesa lands between Lakeside and San Diego, and additional areas might be irrigated if an adequate supply of water could be assured. Two storage reservoirs have been constructed: The Cuyamaca reservoir is on Boulder Creek, at an elevation of 4,600 feet above sea level, and has a capacity of 11,400 acre-feet with a 35-foot earthen dam. La Mesa reservoir is in the foothills about 2 miles northwest of the town of La Mesa, at an elevation of 435 feet. The dam is of earth and rock, is 66 feet high, and has a storage capacity of about 1,500 acre-feet. La Mesa reservoir is filled by water diverted from San Diego River during the winter months. SAN DIEGO RDTER AT DFTERTING DAM NEAR LAKESIDE, CAL. Location*. — In the XE. ^ sec. 11, T. 14 S., B. 2 E., at the intake of San Diego flume, 1,000 feet below mouth of Boulder Creek, and about 13 miles northeast of Lake- side, San Diego County. Drainage area. — 102 square miles (measured on topographic maps). Elevation. — ^About 800 feet sbove sea level. Records available. — October 1, 1912 to January, 1916. Extremes of discharge. — 1912-1915: Maximum stage recorded, 11.6 feet January 27, 1914, and March 20, 1915 (discharge, 2,380 second-feet); no flow over dam for several months during each year. The low- water discharge is diverted into San Diego flume. Discharge for January, 1916. — Mr. W. S. Post, coiLsulting engineer for Cuyamaca Water Co., furnished the tables of discharge for the month of January, 1916. A rating curve has been developed by the Geological Surv^ey covering the discharge to 2,400 second-feet. The discharge during the flood periods was computed from a weir formula for the dam. FLOOD RUN-OFF. 51 Storage. — See Cuyamaca reservoir near Julian. C'al. Accuracy. — The maximum discharge for January-, 1916, as determined by the weir formula, was checked by data on slope and cross section obtained after the flood. Discharge, in second-feet, of San Diego River at diverting dam near Lakeside, Cal., for JaniLary, 1916. Date. Hour. Instan- taneous dis- charge. Instan- taneous Cuya- maca Waste. Instan- taneous discharge from 90 square rmles.a -■ Jan. 13 6 a. m 6 a. m 6p. m 6 a. m 6p. m 6 a. m 6p.m.... 6 a. m 6 a. m 12m 6 a. m 12m 6p. m 12p. m 6 a. m 12m 6p. m 6 a. m 6p.m 6 a. m 6p. m 6 a. m 6 a. m 6p. m 6 a. m 6p. m 6a. m 6p.m 6 a. m 6p. m 12m 12m 24 24 28 130 130 130 349 4,120 4,710 1,970 1,970 2,190 1,-560 7,030 1,070 1,070 350 526 540 346 271 205 205 203 283 272 535 1,230 528 1,710 15,800 5,800 3,240 110 no 110 110 110 no no 106 40 900 700 400 24 14 22 15 28 130 16 130 130 17 . 349 4,120 IS 4,710 19 1,970 1,860 20 2,080 1,450 6,920 960 21 960 240 420 22 540 346 23 271 205 24 205 203 25 283 272 26 -- 535 1,190 27 528 1,710 28 14,900 29 5,100 30 2,840 a Does not include 12 square miles of drainage tributary to Cuyamaca reservoir. Daily discharge, in second-feet, of San Diego River at diverting dam near Lakeside, for Jamiary, 1916. Cal, Date. Total dis- charge, including Cuyamaca waste. Waste, Cuyamaca reservoir. Total dis- charge from 90 square miles, ex- clusive of Cuvamaca basin. Date. 1 Total dis- charge, including Cuyamaca waste. Waste, Cuyamaca reservoir. Total dis- charge from 90 square miles, ex- clusive of Cuyamaca basin. Jan. 1-12 13 14 15 16 17 18 19 20 21 369 36 54 147 ■ 1,581 4,410 2,655 1,815 727 409 33 106 106 65 369 36 54 147 1.581 4.410 2.622 1,709 621 343 i Jan. 22 23 24 25 26 27 28 29 30 31 276 205 2&4 509 929 10.200 10.900 5,910 3.070 2,227 11 23 820 1,877 815 550 345 276 205 26-1 498 906 9.380 9,021 5,095 2,520 1.882 Total runoff for monthj^^^^^^ :^^j,- -^-^^^v^- 92,800 17.06 52 SOUTHERN CALIFORNIA FLOODS OF JANUARY, 1916. SAN DIEGO RIVER AT CAPITAN GRANDE DAM SITE, NEAR LAKESIDE, CAL. Location. — 1,000 feet upstream from the west line of sec. 8, T. 15 S., R. 2 E., in Capi- tan Grande Indian Reservation, about half a mile below mouth of Chocolate Creek, 1^ miles below mouth of South Fork of San Diego River, and 7^ miles northeast of Lakeside, San Diego County. Drainage area. — 189 square miles (measured on topographic map). Elevation. — About 600 feet above sea level. Maximum discharge in January, 1916. — ^J. F. Covert, chief engineer, Sweetwater Water Co., measured cross sections and slope at this point and computed the maximum discharge as follows: First section. — ^Mean area, 2,151 square feet; mean wet perimeter, 205 feet; mean hydraulic radius, 10.5; slope, 0.0035; assumed value of n in Kutter's for- mula, 0.03; coefficient c, 74; mean velocity, 14.2 feet per second. Second section. — Mean area, 480 square feet; mean wet perimeter, 118 feet; mean hydraulic radius, 4.1; slope, 0.0035; assumed value of n in Kutter's for- mula, 0.035; coefficient c, 54; mean velocity, 6.5 feet per second. Total discharge, 34,600 second-feet, or 183 second-feet per square mile of drain- age area. W. S. Post, consulting engineer for Cuyamaca Water Co., obtained the follow- ing flood data at approximately the same location (PI. XI, A): Width, 187 feet; wet perimeter, 196 feet; area, 2,620 square feet; hydraulic radius, 13.4; slope, 0.0035 (in 1,600 reet). If the value of n in Kutter's formula is assumed as 0.035 the discharge is 38,000 second-feet, or 201 second-feet per square mile of drain- age area. This discharge occurred during the aiternjon of January 27. The crest reached Lakeside about 2 p. m. SAN DIEGO RIVER NEAR SANTEE, CAL. Location. — In El Cajon grant at Mssion dam, just above Oak Canyon, about half a mile below Spring Canyon, and 4^ miles west of Santee, San Diego County. Drainage area. — 375 square miles (measured on topographic maps). Elevation. — ^About 275 feet above sea level,. Records available. — ^May 25, 1912, to January, 1916. Extremes of discharge. — 1912-1915: Maximum stage recorded, 13.6 feet Feb- ruary 11, 1915 (discharge, 3,960 second-feet); minimum stage, dry for several months each year except for the small amount of ground water rising to the sur- face at the dam. Maximum discharge in January, 1916. — On March 12, 1916. a cross section was taken 450 feet above the dam (PI. XII, A). The channel, which is in sand, is straight for some distance above and below the section measured for slope. The high water removed practically all brush and trees along both banks and left the channel clean and smooth. It is believed that the remains of the old Mission dam acted as a control and prevented, at least to a considerable extent, the scour that would otherwise have occurred in the bed of the stream. On this account no allowance for scour has been made in computing the area at maximum stage. The crest of the flood reached the gaging station during the afternoon of Jan- uary 27. At Lakeside (PI. XIII), 8^ miles upstream, it was reported that the crest occurred between 2 and 4 p. m. and at San Diego, 12^ miles downstream, at 7 p. m. The maximum gage height at the dam was 25.1 feet (291.5 feet above sea level). The discharge is estimated as follows: Width, 310 feet; wet perimeter, 320 feet; area, 4,200 square feet; hydraulic radius, 13.1; slope of water surface on March 12, 1916, 0.0037 (for 875 feet). If the value of n in Kutter's formula is assumed as 0.03, the discharge was 70,200 second-feet, or 187 second-feet per square mile of drainage area. U. 6. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 426 PLATE XII ^Smsmr '-B*^ — A. VIEW UP SAN DIEGO RIVER AT MISSION DAM, NEAR SANTEE, AFTER FLOOD OF JANUARY, 1916. B. VIEW UP fy/IISSION VALLEY, SAN DIEGO RIVER, FROM OLD MUNICIPAL PUMPING PLANT, AFTER FLOOD OF JANUARY 1916. FLOOD RUN-OFF. 53 Measurements of croes sections and slope, above and below Mission dam, made by J. F. Covert, engineer, Sweetwater Water Co., were used by F. C. Finkle, consulting engineer, to compute the maximum discharge, %v-ith the following results: At Mission dmn. — Mean area, 5,272 square feet; mean wet perimeter, 390 feet; mean hydraulic radius, 13.5; slope, 0.0027; assumed value of n in Kutter's formula, 0.03; coefficient c, 76.9; mean velocity, 14.7 feet per second; discharge, 77,390 second-feet. Two miUs belou: }fission dam. — Mean area, 4.884 square feet; mean wet perimeter, 286 feet; mean hydraulic radius, 17.1 ; slope, 0.0031 ; assumed value of n in Kutter s formula, 0.035; coefficient c, 69.7; mean velocity, 16.1 feet per second; discharge, 78,510 second-feet. SAN DIEGO RIVER AT SAN DIEGO, CAL. Location. — At highway bridge in Block 391, Old Town subdivision, city of San Diego, San Diego County, and about 1^ miles above mouth (PL VII, A). Draixage area. — i34 square miles (measured on topographic maps); 431 square miles at Murray Canyon ford, 2 miles upstream. Elevatiox. — Practically sea level. Records available. — October 1, 1912. to Januarj", 1916. Gage. — Inclined staff on leit bank at bridge. Discharge measurements. — Made from concrete highway bridge until its failure at 2.20 p. m., January 27, 1916; after this date at the Atchison, Topeka & Santa Fe Railway bridge, a short distance below. Channel and control. — Composed of sand; shifting. Extreme of discharge. — 1912-1915: Maximum stage recorded,, 16.61 feet February 21, 1914 (approximate discharge, 9,500 second-feet); minimum stage, dry for several months during each year. Maximum discharge in January, 1916. — The crest of the second flood occurred at 7 p. m., January 27. The discharge was estimated as 75.000 second-feet, or 173 second-feet per square mile. Accuracy. — On account of the shifting of the channel, the gage height record for periods not covered by discharge measurements is of little value. Daily dis- charge reported was computed from a hydrograph drawn through the discharge measurements and conforming in general shape with that determined for San Luis R^y River at Oceanside. The crest discharge on Januar}' 27, 1916, was estimated from the computed maximum discharge at Mission dam. Results considered fair. 54 SOT^TTTERN C.\LTFORNT.\ FLOODS OF .TANTT.\RY, 1016. Discharge nuasurements of San Diego River at San Diego, Cal. , duriing January, 1916. Afudo by— GaRc height. Dis- charge. Remarks. Dalo. Time of measure- ment. Method. Jan. 17 R.W.Day Feet 13.55 13.45 13.34 12.1 9.1 7.8 7.1 9.9 9.98 Sec. -ft. 10,400 10.100 7,380 8,650 2,180 1,820 1,270 11,100 6,560 9 a. m Plnats- 17 do 10 a. m 1 Do. 18 do 3p.m ' Do. Noon . ...' Do. 19 Ellis and MoFadden 20 do 11 a. m Do. 21 W. D. McFadden Noon Meter. 22 do .. do Do. 28 Ellis and Dav 9 a. m Floats. 29 R. W. Dav . -■ 11 a. m Do. Note. — Mean velocities taken as 85 per cent of surface velocities obtained from floats. Gage height, in feet, and discharge, in second-feet, of San Diego River at San Diego, Cal., for January, 1916. Date. Time. Gage height. Dis- charge. Mean daily discharge. Jan. 1-16 Drv 17 9.30 a.m.. 12p.m.... 3p.m 12m 11a.m.... 12m 12m 12m 10 a.m.... 11a. m — 11 a. -m.... 4p.m 7 a. m 3.30 p.m.. 7p.m 9 a. m 11a.m.... 13.5 13.85 13.34 12.1 9.1 7.8 7.1 7.3 7.2 6.9 8.0 8.1 12.0 17.3 19.3 9.9 9.98 10,200 32,000 7,380 8,650 2,180 1,820 1,270 1,400 1,330 1,130 2,600 3,000 18,200 59,500 75,000 11,100 6,560 13,400 18.- 12 700 19 7' 320 2,550 1,760 20 . . 21 22 1 310 23 1^380 1 260 24 25 l'280 26 3,000 27 38,000 28 - 13,200 5,980 2,750 29 30 31 1,280 acre-feet 213,000 Total run-oflformonthjf^^^i^l^-^-jj;---^^-^^^-- 9.19 Note. — Water began flowing early in morning, Jan. 17; crest of first flood at midnight Jan. 17; crest of second flood at 7 p. m., Jan. 27. Concrete highway bridge failed at 2.20 p. m. Jan. 27. BOITLDER CREEK AT CTTYAMACA RESERVOIR, NEAR JULIAN, CAL. Location. — In Cuyamaca grant, 12 miles above junction with San Diego River, and 7 miles south of Julian, San Diego County. Drainage area. — 12 square miles, including area of reservoir, which is about 1 square mile (measured on topographic map). Elevation. — About 4,650 feet above sea level. Records available. — ^June 19, 1912, to January, 1916. Records show only the amount of stored water released to supply San Diego flume. Reservoir. — Cuyamaca dam, completed in 1886, was one of the first earth dams built in Cahfomia for irrigation storage. The height, as originally constructed, was 35 feet. In 1894 the dam was enlarged, increasing the capacity of the reservoir to 11,400 acre-feet. The present dam is 635 feet long and 41^ feet high, having an upstream slope of 2 :1 and a downstream slope of 1^ :1. The water released from the reservoir flows down the natural channel of Boulder Creek and San Diego River to the intake of San Diego flume. FLOOD RUN-OFF. 55 Flood discharge January, 1916.— W. S. Post, consulting engineer for Cuyamaca Water Co., computed the run-off, from the 11 square miles of drainage area tribu- tary to the reservoir, for January 13 to 31, 1916. The estimates, which follow, are based upon very complete reports which give elevation of water surface in the reservoir, spillway discharge, rainfall records, etc. Discharge, in second-feet, of Boulder Creek at Cuyamaca reservoir, near Julian, for January, 1916. Cal. Date. Hour. Instan- taneous discharge from 11 square miles .o Instan- taneous discharge per square mile. Total discharge from 11 square miles. Jan. 13 14 6pm ..... 3 59 12.5 534 865 456 20 39 32 29 715 1,825 1,671 2,393 1,126 3S3 380 200 137 SS 100 95 3 6 p ni . 5 11 48 79 41 59 15 125 16 534 17 5pm - 865 18 456 19 20 6pm .... 21 6p m . 2 3 3 3 20 22 39 23 .32 24 29 25 26 65 166 152 217 102 35 35 17 12 8 9 9 715 27 8 a. m 2,100 10 a m 28 6am '- 823 29 6am 153 30 6am 137 31 6am . -. 120 o Does not include precipitation on reservoir area, which is about 1 square mile. Totalrun-offformonth{^^^v^i;^-;^,:^g---^ SAN VICENTE CREEK AT FOSTER, CAL. Location. — In sec. 31, T. 14 S., R. 1 E., about three-eighths of a mile above Foster, San Diego Coimty, and 3| miles above junction with San Diego River. Drainage area. — 74.9 square miles (measured on topographic map). Elevation. — ^About 500 feet above sea level. Records available. — January 29 to April 4, 1915. Extremes of discharge. — 1915: Maximum stage recorded, 6.5 feet February 11, 1915 (discharge, 1,190 second-feet); minimum stage, drj- for several months during the year. Maximum discharge January, 1916. — On March 15, 1916, a cross section was measured 600 feet above abandoned gaging station (PI. XI, B). The bed is composed of sand, fine gravel, and small boulders ; channel clean except for trees and brush that grow along banks near the high water mark. The water was over the highway on left bank at the point where the cross-section was taken. The high-water slope was found to be 2.44 feet in 685 feet, which was somewhat less than the slope of the present water surface, owing probably to the slight con- traction of the channel and cur\'ature below. The channel is practically straight for the distance covered by the slope data. The maximum discharge, which occurred January 27, is estimated as follows: Width, 190 feet; wet perimeter, 198 feet; area, 1,940 square feet; high water slope, .0036. If the value of n in Kutter's formula is assumed a.s .045, the discharge is 18,600 second-feet, or 248 second-feet per square mile of drainage area. 56 SOUTHERN CALIFORNIA FLOODS OF JANUARY, 19U. SWITZER CANYON AT SAN DIEGO, CAL. The following information was furnished by Mr. George Cromwell, city engineer, San Diego, Cal.: The drainage area of this stream above the point of measurement is 3. 55 square miles: 1 square mile lies within the City Park and, except for a small part under cultivation, is in its original state as rough land covered with brush; and 2, 55 square miles comprise subdi^dded residence property with graded streets. The maximum rate of run-off, which occurred at 7 a. m., January 27, 1916, was 668.5 second-feet, or 188 second-feet per square mile. SAN DIE QUITO BIVER BASIN. GENERAL FEATURES. San Dieguito River, or Saiita Ysabel Creek, as it is known from its source to the San Pasqual Valley, rises in the Volcan Mountains on the western slope of the Coast Eange and flows westward through San Pasqual Valley, below which it takes its true name, and dis- charges into the Pacific Ocean midway between Oceanside and San Diego. Its length is 50 miles, and the maximum wddth of the drain- age basin about 15 miles. The total drainage area is approximately 340 square miles. It lies south of San Luis Rey River and north of the San Diego River basin. Numerous small tributaries enter Santa Ysabel Creek from its source to San Pasqual VaUey, the most important being Black Can- yon and Temescal creeks from the north and Santa Maria Creek from the south. Above the San Pasqual VaUey the creek maintains a light flow throughout the year, but below that point the channel is dry during the summer months. The upper part of the basin is rough, the surface being cut by many canyons. The lower part in the foothills is more roUing, with large areas of vaUey and high mesa land. The formation is a loose granite. The basin has very little timber, the principal cover being brush, grass, and a few scattered oaks. The mean annual ramfall ranges from 10 to 15 inches along the foothills and from 20 to 40 inches in the moimtains. SANTA YSABEL CREEK NEAR MESA GRANDE, CAL. Location.— In the NW. ^ sec. 21, T. 12 S., R. 2 E., at Sutherland dam site, about 1 mile below Sutherland, 1| miles above mouth of Black Canyon Creek, and 4^ miles southwest of Mesa Grande, San Diego County. Drainage area. — 53.4 square miles (measured on topographic map). Elevation. — ^About 1,900 feet above sea level. Records available. — December 29, 1912, to January, 1916. Gage. — Friez water-stage recorder on right bank just above dam site; instrument was removed by flood January 27. Discharge measurements. — Made from cable at gage or by wading; equipment destroyed by the January flood. FLOOD RUX-OFF. 57 Channel and control. — Shifting sand above and below station. A concrete control was constructed at an outcropping of bedrock 20 feet below gage. Banks are high, covered with brush, and not likely to be overflowed. Zero flow occurs at zero gage height. Extremes of discharge. — 1912-1915: Maximum stage recorded, 4.53 feet Feb- ruary 11, 1915 (discharge, 1,040 second-feet); minimum stage dr>- October 1 and 2, 1913, August 12 to 29 and September G to 13, 1914. Maximum discharge in January, 1916. — The maximum stage was 11.0 feet at noon January 27. Measurements of cross-section and slope made a short distance above Ramona-Mesa Grande highway bridge (PI. XIV, A) and about a mile below gaging station on May 23, 1916, were furnished by W. S. Post, consulting engineer for Volcan Land & Water Co., as follows; Area, 1,180 square feet; wet perimeter, 149 feet; hydraulic radius, 7. 9; high water slope from 500 feet above cross-section to 500 feet below, 0. 02; width, 144 feet. If tlT^'alue of n in Kutter's formula is assumed as 0. 5 (channel composed of boulders and is rough), the discharge is 21,100 second-feet, or 395 second-feet per square mile of drainage area. Accuracy. — Results during flood period are considered fair. Water-stage recorder was in operation January 1 to 15 and 22 to 27. For the remainder of the month the staff gage was read once or twice daily. The following discharge measurement was made by W. J. Isbell: January 11, 3916: Gage-height, 1.04 feet; discharge, 35 second-feet. Discharge, in second-feet, of Santa Ysahel Creek near Mesa Grande, Cal.,for January, 1916. Date. Maximum. Minimirai. Mean. Date. Maximum. Minimum. Mean. Jan. 1 t 4 10 12 9 10 10 9.5 8 18 62 45 19 15 36 54 405 Jan. 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 10.600 6.500 3.660 1,940 1,550 2. 500 1.940 650 4,130 2 1 4.200 3 2 580 4 1 1.280 5 500 6 1 480 7 1 225 8 i 200 9 1 660 460 21.100 8.550 2.400 200 350 400 2.400 1.000 416 10 1 406 11 i 10.800 12 1 4,720 13 . 1.520 14 800 15 560 16 1.750 50 Total runK,a for mon,h{5Jp^^«t inikVsontoinage- ;u-oa :;;;; ^ SANTA YSABEL CREEK NEAR RAMONA. CAL. Location.— In the XE. \ sec. 27, T. 12 S., R. 1 E., at Pamo Camp, 1 mile below mouth of Temescal Creek, and about 4 miles north of Ramona, San Diego County. Drainage area. — 110 square miles (measured on topographic map). Elevation. — About 925 feet above sea level. Records available. — February 5, 1912, to January, 1916. Gage. — Staff in four sections on left bank, with a short vertical section at concrete control for use during extreme low water. Read three times a day and more frequently during high water. Destroyed by high water January 16. Observa- tions for the remainder of the month were made by setting stakes at water sur- face and later referring them to gage datum by leveling. Xew staff was installed January 31 at proposed dam site about half a mile down stream. Discharge measurements. — Made from cable at gage or by wading. Cable was washed out on January 17, reinstalled January 26, and again destroyed Janu- ary' 27. 58 SOUTHERN CALIFORNIA FLOODS OF JANUARr^ 1016. Channel and control. — Composed of sand and some boulders; somewhat shifting. On November 19, 1912, a concrete control was built about 30 feet below gage. The floods January 17 and 27, 1916, formed an entirely new channel to left of control. Extremes of discharge. — 1912-1915: Maximum stage recorded, 8.05 feet, Feb- ruary 11, 1915 (discharge, 3,330 second-feet); minimum stage, 0.74 foot, October 1 to 6, 1915 (discharge, 0.1 second-foot). Maximum discharge in January, 1916. — Measurements of cross section and slope data were made March 14, 1916, about half a mile below gaging station (PI. XIV, B). The channel, which is composed of large boulders, gravel, and sand, is a little rough, and is clean, except for a few small willows. It is slightly curved between points covered by slope data. The maximum discharge, which occurred at 7 p. m. January 27, has been computed as follows: Width, 271 feet; wet perimeter, 276 feet; area, 2,070 square feet; hydraulic radius, 7.5; slope of present water surface, 0.0067 (for 455 feet). If the value of n in Kutter's formula is assumed as 0.035, the discharge is 28,400 second-feet, or 258 second-feet per square mile of drainage area. The crest of the flood at 9 p. m., January 17, estimated from the Mesa Grande record, was 14,300 second-feet. Accuracy. — Results considered approximate. The gage-height records January 1 to 15 were lost during the flood. Discharge for this period estimated from Mesa Grande record and hydrographer's notes. Discharge January 16 to 30 computed from a hydrograph defined by discharge measurements and computed discharge, and having the general shape of the hydrograph for Santa Ysabel Creek near Mesa Grande. Discharge measurements of Santa Ysabel Creek near Bamona, Cal., for January and February, 1916. Date. Made by — heigS. Dis- charge, Date. Made by— Gage height. Dis- charge. Jan. 11 W. J. Isbell Feet. 1.83 2.50 Sec.-ft. 69 531 Feb. 1 W.D. McFadden Feet. 4.80 Sec.-ft. a 742 26 W. D. McFadden a Float measurement. Mean daily discharge, in second-feet, of Santa Ysabel Creek near Ramona, Cal., for Jan- uary, 1916. Day. Discharge. Day. Discharge. Day. Discharge. Day. Discharge. Jan.! 7 Jaa. 9 28 Jan. 17 6.060 Jan. 25 668 2 17 10 95 18 7.420 26 611 3 20 11 69 19 3,680 27 14,100 4 15 12 29 20 2,110 28 9,740 5 17 13 23 21 865 29 2,540 6 17 14 55 22 560 30 1,160 7 15 15 81 23 450 31 '865 8 12 16 664 24 400 Total run-ofl for month{5^^i-i^-;i,^g-^^;;;;;;;;:;;;;;::;;;;;;;^ SAN DIEGinTO RIVER NEAR BERNARDO, CAL. Location.— In the SE. \ NW. i sec. 18, T. 13 S., R. 2 W., at Carroll dam site, 5i miles downstream from former station at Bernardo bridge, about 10 J miles above mouth of river, and 4 miles southwest of Bernardo, San Diego County. U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 426 PLATE XIV A. VIEW UPSTREAM ON SANTA YSABEL CREEK NEAR MESA GRANDE, AFTER FLOOD OF JANUARY, 1916. B. VIEW ACROSS SANTA YSABEL CREEK NEAR RAMONA, AFTER FLOOD OF JANUARY, 1916. U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 426 PLATE XV A. VIEW DOWNSTREAM ON SAN DIEGUITO RIVER AT CARROLL DAM SITE. NEAR BERNARDO, AFTER FLOOD OF JANUARY, 1916. B. VIEW DOZ/NSTREAVi ON SANTA MARIA CREEK NEAR RAMONA, IN 1917. FLOOD RrX-OFF. .9 Drainage area. — 299 square miles (measured on topographic maps); 266 square miles for station at Bernardo. Elevation. — About 150 feet above sea level. Records available. — April 17, 1912, to September 30, 1915, for station at Bernardo. Gage. — Vertical staff in 4 sf.-ctions on right bank at dam site. Discharge measurements. — Equipment not yet installed. Wading measurements have been made at gage. Channel and control. — Shifting sand with bed rock outcropping about 400 feet below gage (PI. XV, A). Extremes of discharge. — 1912-1915: Maximum stage recorded, 17.8 feet February 11, 1915 (discharge, 5,050 second-feet) ; minimum stage, practically dr\' for several months each year (for Bernardo station). Maximum discharge in January, 1916. — The maximum stage was reported as 21. 2 feet and occurred at from 1 p. m. to 3 p. m. January 27. Measurements of slope and two cross sections made at the dam site were furnished by W. S. Post, con- sulting engineer for Volcan Land &. Water Co.. as follows: Mean area. 4,870 square feet (correction was made for scour in channel as a profile of the bed rock was available); mean hydraulic radius, 17.25; high-water slope, 0.0033 (for 705 feet). If the value of n in Kutter's formula is assumed as 0.04, the discharge is 72,100 second-feet, or 241 second-feet per square mile of drainage area. Accuracy. — Discharge January 1 to 16 computed from records obtained at station at Bernardo. On January 17 the equipment at this station was destroyed and the channel greatly changed by the high water. For January 17 to 31, discharge record at Carroll dam site has been fiu-nished by W. S. Post. These computations are based upon the gage-height record and rating cur\-es defined by later meas- urements and flood discharge computed from data on cross section and slope. Mean daily discharge computed from hydrograph defined by these data and con- forming in general shape to the hydrographs for other stations in the same and adjoining drainage basins. Mean daily discharge, in second-feet, of San Dieguito River near Bernardo, Cal.,for Jan- uary, 1916. Day. Discharge. Day. Discharge. Day. Discharge. Dav. Discharge. Jan. 1 22 Jan. 9 32 Jan. 17 11.800 Jan. 25 1.060 2 22 10 45 18 27,000 1 26 2,950 3 27 11 257 19 14,800 27 37,200 4 22 12 100 20 5.220 28 15,100 5 22 13 82 ! 21 1,730 29 4.750 6 32 14 74 22 909 1 30 2.200 7 32 15 230 ; 23 662 31 1.220 8 32, 16 1,310 1 " 708 Totalrui«)ffformonth{^^^;,i^^--^|^^^^;;;;;;;;;;:;;: ;;;;;;;::;:;;;;;^ Note.— Discharge. Jan. 1-16, is for former station at Bernardo. The nin-off for this period for the area between Bernardo bridge and Carroll dam site is beUeved to be negligible. SANTA MABTA CREEK NEAR RAMONA, CAJL. Location. — In the SE. \ sec. 11. T. 13 S., R. 1 W.. about 7 miles below mouth of Hatfield Creek, and 5^ miles west of Ramona, San Diego County. Drainage area. — 57.3 square miles (measured on topographic map). Elevation. — About 1,300 feet above sea level. Records available. — November 6, 1912 to January, 1916. Gage. — Friez water-stage recorder on right bank just above concrete control, with staff in two sections on opposite bank. Water-stage recorder was destroyed by Januarj" flood. Discharge measurements. — Made from cable 100 feet below gage or by wading; equipment was destroy eil by the January flood. 60 SOTTTITERN CALIFORNIA FLOODS OF JANUARY, 1916. Channel AND CONTROL. — Shifting sand above and below station. Concrete control installed just below gage at an outcropping of solid rock. Zero flow occurs at a gage height of about l.:^2 feet. About 1,000 feet below gage, valley narrows to a rocky gorge at proposed dam site. There appears to be considerable natural storage in the channel at extreme high water. The slope of the water surface at maximum flood stage was found to be much less than at low or medium discharge. Extremes of discharge. — 1912-1915: Maximum stage recorded, 7.05 feet February 10, 1915 (discharge 1,890 second-feet); minimum stage, dry for several months each year. Maximum discharge in January, 191G. — Measurements of slope and cross seQtion were made at the gaging station (PI. XV, B) on March 14, 1916. The cross sec- tion was taken 315 feet below staff gage. The channel, which is composed prin- cipally of sand, is straight and clean except for a few trees on left bank below gage. About 1,000 feet below station valley narrows to a rock gorge which causes some natural storage in the channel during flood stages. The maximum gage height, as determined from flood marks, was 15.9 feet and occurred at about 5 p. m. January 27. The maximum discharge has been computed as follows: Width, 238 feet; wet perimeter, 242 feet; area, 2,040 square feet; hydraulic radius, 8.4; slope of water surface at maximum stage, 0.00037 (for 1,010 feet). The slope of the water surface March 14 was 0.0059 (for 575 feet) . If the value of n in Kutter's formula is assumed as 0.035, the discharge is 7.140 second-feet, or 125 second-feet per square mile or drainage area. Accuracy. — Results considered reliable. Gage was read two to six times a day during high water. The concrete control was not injured by the flood. Discharge measurements of Santa Maria Creek near Ramona, Cal.,for January and February^ 1916. Date. Made by— Gage height. Dis- charge. Date. Made by- height. Dis- charge. Jan 4 W. J. Isbell Feet. 1.37 1.80 Sec-n. 2.4 Jan. 24 Feb. 3 W. D. McFadden Day and McFadden.... Feet. 2.70 3.45 Sec.-ft. 11 do 144 Discharge, in second-feet, of Santa Maria Creek near Ramona, Cal.,for January, 1916. Date. Maximvim. Minimum. Mean. Date. Maximum. Minimum. Mean. Jan. 1 0.2 .2 .2 .0 .0 .0 .0 .2 .2 .4 2.4 1.5 1.0 2.5 4.0 1,200 Jan. 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 3,720 3,310 1,280 518 178 150 90 71 816 3,360 7,140 2,880 430 410 208 2,210 1,280 518 178 150 90 71 71 71 816 2,880 430 112 208 136 2,820 2 1,960 3 914 4 283 5 163 6 113 7 78 8 71 9 275 10 1,970 11 4,960 12 1,370 13 223 14 322 15 150 16 Total nin-ofl for month facre-feet 33,500 \depth in inches on drainage area 10.96 Note.— Discharge January 4 to 7 less than 0.1 second-foot. FLOOD KUN-OPF. 61 SAN LUIS BEY RIVER BASIN. GENERAL FEATURES. San Luis Rey River drains an area comprising 565 square miles lying wholly in the northern part of San Diego County and extending from the crest of the Coast Range to the Pacific Ocean, a distance of 65 miles, with a maximimi width of about 16 miles. The river is formed hy many small streams which rise in the higher elevations of the Coast Range and come together at the lower or west end of what is known as Warner's valley. Below this point the river flows for a distance of 10 miles through a deep narrow canyon with a heavy grade, then over a sandy and gravelly bed with medium grade for some 40 miles, finally discharging into the Pacific Ocean at Oceanside. Altitudes wdthin this basin range from 50 to 500 feet in the foothills in the vicinity of Oceanside and from 500 to 6,000 feet on the moun- tains. Palomar Mountain, the highest peak in the basin, is 6,126 feet above sea level. The upper portion of the basin is more or less rolling, and several of the valleys are under cultivation and are used extensively for stock raising; the middle part, occupied by the river in its canyon, is rough ; on the lower reaches the surface becomes less rugged, merging into the foothills, which extend to the coast. The rocks are granitic. The basin is poorly forested. Some fairly good timber is found on the higher elevations, but the greater part of the cover is brush and grass with a scattered growth of oaks. The mean annual precipitation in this basin ranges from about 10 to 50 inches, gi-adually increasing with altitude. It occm^s almost entii'ely as rain, snow appearing only occasionally on the high eleva- tions. SAN LUIS REY RIVER NEAR MESA GRANDE, CAL. Location, — In the NE. ^ sec. 9, T, 11 S., R. 2 E., 1 mile below Warner dam site and mouth of Carrizo Creek, and about 5 miles north of Mesa Grande, San Diego County. Drainage area. — 209 square miles (measured on topographic and military survey maps). Elevation. — About 2,650 feet above sea level. Kecords available. — October 3, 1911 to January' 1916. Gage. — Barrett & Lawrence water-stage recorder on left bank just above concrete weir; destroyed by high water during night, January 16, 1916. Staff g:\ge at same location and datum as water-stage recorder read frequently January 17 to 31 by an engineer of the Volcan Land & Water Co. Discharge measurements. — Made from cable about a mile above gage or by wading. Channel and control. — Composed of sand and gravel; somewhat shifting. The concrete weir which acted as a control was practically destroyed by the high water. Extremes of discharge. — 1911-1915: Maximum stage recorded, 7.5 feet February 21, 1914 (discharge 3,470 second-feet); minimum stage, 0.09 foot August 31, 1914 (discharge, estimated, 0.2 second-foot). Maximum discharge in January, 1916. — Measurements of cross sections and slope made a short distance below dam site, were furnished by W. S. Post, consulting engineer, for Volcan Land & Water Co., as follows: 62 SOUTHERN CALIFOBNIA FLOODS OF JANUARY, 1916. Mean area, 2,960 square feet; mean wet perimeter, 242 feet; mean hydraulic radius, 12.2; high water slope over 900-foot range (from 300 feet above to 600 feet below cable), 0.0073. If the value of n in Kutter's fonnula is assumed as 0.035, the discharge is 58,600 second-feet, or 280 second-feet per square mile of dranage area. No correction was made to the area for probable scour in channel at crest of flood. Accuracy. — ^Results considered good. Gage read frequently except durrng night. Discharge measurements of San Luis Rey River near Mesa Grande, Cal., during January, 1916. Made by ^X. J. Isbell. Date. Gage height. Dis- charge. Time of measure- ment. Date. Gage height. Dis- charge. Time of measure- ment. Jan. 1 Feet. 0.35 .42 .39 .85 1.58 Sec-ft. 16 24 21 103 248 Jan. 18 Fed. 9.06 5.44 1.78 2.38 6.70 Sec-ft. a 9. 8.50 2,630 364 o561 O3.830 3. 9 a.m. 4 p. m 11 a. m 11a. m 19 3p.m. 11a m 7 23 9 26 16 28 11 a m a Made from cable. Discharge, in second-feet, of San Luis Rey River near Mesa Grande, Cal., for January, 1916. Date. Maximum. Minim tun. Mean. Date. Maximum. Minimum. Mean. Jan. 1 2 3 4 5 6 7 8 9 10 ! 16 25 24 20 29 36 21 16 103 40 42 43 44 46 170 1,550 Jan. 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 24,400 15,600 4,350 1,580 595 478 390 425 1,190 1,990 58,600 21,700 3,200 2,770 1,160 4,800 4,350 1,580 595 478 390 325 325 355 425 1,990 2,130 1,630 1,160 895 13,000 10,100 2,740 896 536 L. 428 1 352 1 354 775 806 11 1 28,100 6,130 12 1 13 :.:.::::i. .::..:::::.:: 2,060 14 1 1,610 15 i 1,020 16 5,300 210 Total run-ofl for month{^^^^i^-;^V-^,--;:;;;;;:;;;:;;:;:;::^ Note.— Crest of flood Jan. 17 occurred at 1.45 p. m., gage height 12.8 feet; January 27 at 4.30 p. m., gage height 18.0 feet. SAN LinS REY RITTER NEAR NELLIE, CAL. Location. — In Potrero Indian Reservation (near west Hne of sec. 33, T. 10 S., R. 1 E., unsurveyed), 500 feet above intake of Escondido Mutual Water Co.'s canal, 8 miles below gaging station at Warner dam site near Mesa Grande, and about 4^ miles southwest of Nellie, San Diego County. Drainage area. — 240 square miles (measured on topographic and miHtary-survey maps). Elevation. — About 1,800 feet above sea level. Gage. — Friez water-stage recorder on left bank, with reinforced concrete well, 500 feet above intake of Escondido Mutual Water Co.'s canal; equipment destroyed by January flood. Discharge measurements. — Made from cable 400 feet above gage or by wading; equipment destroyed by January flood. FLOOD RUN-OFF. 63 Channel and control. — Composed of sand and boulders overlying solid rock. A concrete control, extending to bedrock, was built across channel about 30 feet below gage. Accuracy. — Record for January considered approximate. No gage-height record available, except January 1 to 8, as water-stage recorder was destroyed by the flood. Discharge January 9 to 14 estimated from ^lesa Grande record, that for rest of month estimated from flood studies at Mesa Grande, records at Oceanside, and mean rainfall computed for drainage area. Discharge measurements of San Luis Bey River, near Nellie, Cal.,for January, 1916. [Made by W. J. Isbell.] Date. Gage hftig?it. Dis- charge. Date. height. Dis- charge. Jan. 8 Feet. 1.30 2.30 Sec.-ft. 22 194 Jan. 22 Feet. 3.02 Sec.-ft. 571 15 Mean daily discharge, in second-feet, of San Luis Rey River near Nellie, Cal.,for January, 1916. Date. Dis- charge. Date. Dis- charge. Date. Dis- charge. Date. Dis- charge. Jan.l 2 3 4 25 43 41 26 Jan. 5 6 7 8 38 48 29 22 Jan. 9 10 11 12 140 55 58 59 Jan. 13 14 15 60 63 194 Total run-ofl for month{g^|Jv^--^^^g^- -;;;;;;;;;;;;;;;;;;;;;;;;;;;;; :;;;;;^ 165^ SAN LUIS REY RIVER NEAR PAT.A. CAL. B. 1 Location. — ^Above ford on road to Sickler's mill, in the NW. \ sec. 31, T. 9 S. W., about 4 miles southeast of Pala, San Diego County. Drainage area.^^322 square miles (measured on topographic and military-survey maps). Elevation. — ^About 575 feet above sea level. Records available.— October 9, 1903 to June 30, 1911, and November 14, 1912, to January, 1916. Gage.— Friez water-stage recorder on left bank 600 feet above ford. Previous to September 19, 1912, records were obtained from staff gage about 50 feet above ford. November 13, 1906, original gage datum was lowered 4.66 feet. Present gage is at an independent datum. "Water-stage recorder was removed by high Water in January; no record after January 16, 1916. Discharge measurbments. — ^Made from cable 550 feet below water-stage recorder or by wading. Channel and control. — Composed of sand, gravel, and boulders; shifting. An artificial control, consisting of short concrete cut-off walls between the boulders, was rebuilt across the channel just below gage on September 28, 1914, and was destroyed by flood of January, 1916. Stage of zero flow for new control, about 5.7 feet. Extremes of discharge.— 1905-1915: Maximum stage recorded, 12.0 feet (original datum) at noon and at 2 p. m. March 24, 1906 (discharge, 22,000 second-feet); minim u m stage, 5.28 feet August 6 and 7, 1907 (discharge, 0.6 second-foot). 64 SOUTHERN CALIFORNIA FLOODS OF JANUARY, 1916. Maximum discharge in January, 191G. — Maximum stage reached during flood was 18.1 feet, as determined by leveling from liigh-\vater mark. IMaximum discharge was approximately 75,000 second-feet (see San Luis Key at Pala). Accuracy. — Besults January 1 to 16 considered good; no gage-height record after January 16, as eqidpment was destroyed. Discharge January 17 to 31 estimated from flood studies of Mesa Grande and Oceanside records, and mean rainfall computed for drainage area. Mean daily discharge, in second-feet, of San Luis Keij River near Pala, Cal.,for January, 1916. Date. Dis- charge. Date. Dis- : charge, i Date. Dis- charge. Date. Dis- charge. Jan. 1 2 3 4 18 18 27 .s Jan. 5 6 7 8 18 26 25 18 Jan. 9 10 11 12 34 119 289 161 Jan. 13 14 15 16 99 92 311 1.660 Total run-off for month/^^^®"^®^* 201,000 lotai run-on lor montH|^gp^j^ ^ .^^^^^ ^^ drainage area 11.76 SAN LUIS REY RIVER AT PALA, CAL. Location. — 300 feet above intake of South Side Pala Indian ditch, below Agua Tibia Creek, 1^ miles below Geological Survey gaging station, and about 1^ miles southeast of Pala, San Diego County. Drainage area. — 322 square miles (at Geological Survey gaging station, 1^ miles upstream, measured on topographic and militar^'-surv^ey maps). Elevation. — ^About 500 feet above sea level. Flood discharge for January, 1916. — ^About 30 days after the flood, Mr. C. H, Southworth, United States Indian Irrigation Service, measured cross-section and slope at this point and computed the maximum discharge for January 27, as follows: Area, 2,690 square feet; wet perimeter, 300 feet; hydraulic radius, 8.9; slope, 0.012; assumed value of n inKutter's formula, 0.025; mean velocity, 28.0 feet per second; discharge, 75,300 second-feet. SAN LUIS REY RIVER AT BONSALL, CAL. Location. — In the SW. i sec. 20, T. 10 S., R. 3 W., at concrete highway bridge at Bonsall, San Diego County, just above Moosa Canyon, about 14 miles below gaging station near Pala, and 14 miles above mouth of river. Drainage area. — 465 square miles (measured on topographic and military surA-ey maps) . Elevation. — About 150 feet above sea level. Records available.— April 16, 1912, to January, 1916. Gage. — Staff in three sections on left bank at bridge; read twice daily. Previous staff was on left bank, 150 feet below present gage. Original datum not maia- tained. Discharge measurements. — Made from bridge at gage or by wading. Channel and control. — Composed of sand; shifting. Extremes of discharge. — 1912-1915: Maximum stage recorded, 7.0 feet February 11, 1915 (discharge 9,000 second-feet); channel dry for several months each year. Maximum discharge in January, 1916. — Gage and highway bridge destroyed by high water; no record after January 15. Maximum discharge not estimated owing to instability of channel. Accuracy. — Results January 1 to 15 considered fair. Discharge for remainder of month estimated from flood studies of Mesa Grande and Oceanside records and mean rainfall computed for drainage area. FLOOD RUN-OFF. 65 Mean daily discharge, in second-feet, of San Luis Rey River at Bonsall, Cat., for January, 1916. Date. Dis- charge. Date. Dis- charge. Date. Dis- charge. Date. Dis- charge. Jan. 1 2 3 4 57 57 57 57 Jan.5 6 7 8 42 42 57 57 Jan. 9...... 10 11 12 57 95 320 162 Jan. 13 14 15 86 86 268 Total run-off for month{^ft^:^-^---^j^-^;; ;;;;;;;;;;;;; ;;;;;;;;- 257^ SAN LXnS REY RIVER AT OCEANSIDE, CAL. Location.— In the SE. \ NE. \ sec. 22, T. 11 S., R. 5 W., at highway bridge about half a mile above mouth, at Oceanside, San Diego County. Drainage area. — 565 square miles (measured on topographic and military survey maps) ; for gaging station opposite Oceanside pumping plant, 1^ miles upstream, 563 square miles. Elevation. — Sea level. Records available. — April 17, 1912, to September 30, 1915, for station opposite Oceanside pumping plant. Discharge measurements. — Made from concrete highway bridge until its failure at 9.30 p. m., January 27, 1916. Later measurements were made from a boat at approximately the same location (PI. VIII, A, p. 32). Channel and control. — Composed of sand; shifting. The discharge measurement made at 6 p. m., January 27, 1916, indicated that the scour in the main channel amounted to about 10 feet as compared with the cross section measured May, 25 1916. Extremes of discharge. — 1912-1915: Maximum stage recorded at station opposite Oceanside pumping plant, 4.9 feet February 11, 1915 (approximate discharge, 7,000 second-feet); channel dry for several months during each year. Maximum discharge in January, 1916. — The crest discharge of the flood on January 17; 1916, was estimated from the Mesa Grande record, using the ratio that obtained for the flood of January 27, at 40,000 second-feet. The crest discharge, which occurred at 9.30 p. m. January 27, was estimated as follows: From a study of the cross section measured May 25 and the measurement at 6 p. m. January 27, it is evident that the maximum stage at 9.30 p. m. was at least 3.0 feet higher than at the time of the measurement. At the pumping plant, 1^ miles upstream, where the channel is much wider, a rise of more than 2 feet was reported. Low tide occurred at 7.15 p. m. January 27; hence the maximum stage was not affected by the tide. Without making any allowance for additional scour in the channel, the area at maximum stage would be 1, 860 square feet greater than at 6 p. m., or a total area of 6,370 square feet. The mean velocity has been estimated as 15 feet per second. For the measurement at 6 p. m. it was 12.3 feet per second. The estimated maximum discharge is 95,600 second-feet, or 169 second-feet per square mile. Accuracy. — Mean daily discharge January 16 to 31, 1916, computed from a hydro- graph based on discharge measurements and compared with the records on San Luis Rey River near Mesa Grande. Results considered fair. 106922°— 18— wsp 426 5 66 SOUTHERN CALIFORNIA FLOODS OF JANUARY, 1916. Discharge Tmasuremmts of San Luis Rey River at Ocearmde, Cal.,for January, 1916. Made by- Gage height. Dis- charge. Remarks. Date. Time of measure- ment. Method. 1916. Jan. 16 McFadden and Ireland Feet. 2.45 6.0 4.0 4.0 3.0 2.5 2.0 1.8 1.4 1.4 1.3 1.3 1.3 1.3 1.4 1.5 1.6 Sec.-ft. 216 27,100 16,200 20,800 9,990 9,080 3,690 2,000 1,650 1,480 1,460 1,240 1,150 1,030 1,310 1,580 1,800 9,640 55,400 21,900 2,190 1,260 9a. m 3p. m 9 a. m 3pm 9 a. m 4 p. m 10 a. m 9 a. m 11a.m.... 4 p. m 9 a. m 4 p. m 9 a. m 4 p. m 9a. m ^P-m 9a. m 10 a. m 6 p. m 9 a. m 4p. m 4 p. m 17 Strout and Ireland 18 do Floats 18 do Do 19 do Do 19 do Do 20 do Do 21 do Meter 22 C. B. Ireland . Do 22 do Do 23 do Do 23 do Do 24 do Do 24 .. do Do 25 25 do do Do. Do 26 do Do. 27 Strout and Ireland Floats. 27 do Do. 28 Do. 30 G. S. Strout Do. 31 do Do. Note.— Mean velocities taken as 80 per cent of surface velocities obtained from floats. Discharge, in second-feet, of San Luis Rey River at Oceanside, Cal.,for January, 1916. Date. Maximum. Minimum. Mean. Date. Maximum. Minimum. Mean. Jan. 16 6.500 216 2.180 Jan. 24 1,200 1.030 1,110 17 40,000 10,000 20.800 25 1,600 1,100 1,400 18 21.500 13,500 18,100 26 3,800 1,600 2,230 19 13.500 5,700 9,640 27 95,600 3,800 33,800 20 5.700 2,400 3,730 28 8.5,000 7,700 28,200 21 2,400 1,700 1,980 29 7,700 3,700 5,330 22 1,700 1,480 1,590 30 3,700 1,800 2,650 23 1,480 1,200 1,350 31 1,800 1,170 1,430 Total run-off for period{g^^-i^--^^^i^ ^- ■";;::;;;;;;;;;;;; ^ MOOSA CANYON CREEK NEAR BONSALL, CAL. Location. — Near the northwest comer of sec. 1, T. 11 S., R. 3 W., at Moose dam, half a mile below mouth of South Fork, and 4^ miles southeast of Bonsall, San Diego County. Drainage area. — 31 square miles (measured on topographic map by John F. Covert). Elevation. — About 400 feet above sea level. Maximum discharge in January, 1916. — John F. Covert, chief engineer Sweet- water Water Co., estimated the discharge over the dam to be 8,346 second -feet. The maximum stage 100 feet upstream from the dam, determined December 15, 1916 , from flood marks was 9.1 feet above crest of dam. The concrete dam is 81 feet long on top and the width of the canyon at a point 9.1 feet above the crest is 105 feet. FLOOD RUN-OFF. 67 SANTA ANA RIVER BASIN. GENERAL FEATTTRES. Of the three principal streams that traverse the valley of south- ern California — Santa Ana, San Gabriel, and Los Angeles rivers — the Santa Ana is the largest. Its drainage basin, lying south of the San Bernardino Mountains and the Sierra Madrc and taking waters from their southern slopes, is the most easterly and comprises by far the largest area, including the northern part of Orange County, the north- western part of Riverside County, and the southwestern part of San Bernardino County. Of the total drainage area, covering between 1,800 and 1,900 square miles, about two-thirds is in the valley, but only a few hundred square miles yields much run-off. The Santa Ana rises in the heart of the San Bernardino Mountains, about 30 miles east of Highland, and flows westward for about 25 miles to the mouth of its upper canyon; thence south westward across San Bernardino Valley, through the lower canyon in the Santa Ana Mountains, and across the coastal plain to the Pacific Ocean at Newport Beach. Although the course of the stream measures about 100 miles, there is continuous surface flow from mountain to sea only during winter floods. Many small streams from the southern slope of the San Bernardino Mountains and a few from the Sierra Madre west of the Cajon Pass flow toward the Santa Ana, but some of these discharge water to the main stream only in the flood seasons, the ordinary flow either being diverted or sinking into the sand and gravel of San Bernardino Valley. The principal tributaries are Bear, Alder, Mill, Lytic, and Chino creeks. Altitudes in the Santa Ana drainage area range from a few feet above sea level on the coastal plain to 2,000 or 3,000 feet on the Santa Ana Mountains, 500 to 1,200 feet in the San Bernardino basin, and 2,000 to 11,000 feet on the southern slope of the San Bernardino Mountains. The more elevated regions are rough and rugged, and the mountain sides are incised by many canyons which are the result of active stream erosion. The rocks are granitic. The mesa and valley lands at the base of the mountains are composed of granitic gravel and sand of great depth. The higher mountain slopes sup- port considerable timber; most of the lower slopes are covered with brush and grass. The mean annual precipitation varies considerably in different parts of the Santa Ana basin. On the coastal plain west of the Santa Ana Range it averages 10 inches or more; eastward, in the San Ber- nardino Valley, it amounts to from 10 to 16 inches. On the moun- tain slopes it ranges from 20 inches at the base to 40 inches or more near the crest, and in Bear Valley north of the highest peaks, such 68 SOUTHERN CALIFORNIA FLOODS OF JANUARY, 1916. as San Bernardino and San Gorgonio, it may be even 50 inches. Considerable snow falls in the region of these high peaks in winter and remains well into the summer, especially on the northern slopes, from which the headwaters of the Santa Ana come. SANTA ANA RIVER NEAR MENTONE, GAL. Location. — In the SW. \ sec. 4, T, 1 S., R. 2 W., just above mouth of canyon, one- fourth mile above Pacific Light & Power Corporation's plant, one-half mile above mouth of Deep Creek, and 3^ miles northeast of Mentone, San Bernardino County. Drainage area. — 189 square miles (measured on topographic maps). Elevation. — About 1,900 feet above sea level. Records available. — July 1, 1896, to January, 1916. Gage. — Vertical staff fastened to rock ledge on left bank one-fourth mile above power house; read daily. Destroyed by high water during night of January 17-18; no record obtained during rest of month. Discharge measurements. — Car and cable at Warm Springs Canyon destroyed by flood. On account of the damage to the highways and bridges it was impossible to reach this station for several days after the flood had passed. Channel and control. — Composed of gravel and boulders; very rough; shifts dur- ing high water. Extremes of discharge. — 189&-1915: Crest gage height January 1, 1910, not known, as gage was destroyed (mean discharge for day estimated as 8,500 second-feet); minimum stage, 2.3 feet during parts of every month from October, 1913, to January, 1915 (discharge, 0.6 second-foot). Maximum discharge in January, 1916. — As the gage was destroyed during the night of January 17-18, there is no record of stage for the month after 8 a. m. January 17. Slope cross section measured at the gaging station March 8, 1916 (PI. XVI, A). The cross section was measured just below temporary highway bridge, 357 feet below gage. The channel, which is composed of large and small boulders, sand, and gravel, is clean and very rough. The slope of the water surface at maximum stage was determined for a distance of 1,620 feet, where the channel was generally straight. The maximum discharge has been computed as follows: Width, 510 feet; wet perimeter, 526 feet; area, 2,290 square feet; hydraulic radius, 4.4; slope of water surface (flood stage), 0.024 (for 1,620 feet). If the value of n in Kutter's formula is assumed as 0.05, the discharge is 29,100 second-feet, or 154 second-feet per square mile of drainage area. For piu-pose of comparison it is interesting to note that the intake of the Mentone power plant, operator's house, and other structures removed by this flood had been in place since the plant was constructed in 1902. Also that a large number of trees, 2 feet in diameter, were brought down by the high water. During the * flood the river at the mouth of the canyon, would swing from one side of the can- yon to the other and back again, within an hour, the action being due to jams formed by great numbers of large boulders moving downstream. Diversions.— The intake of the Pacific Light & Power Corporation's canal is at Southern California Edison Co. plant No. 2, 2^ miles above the gage. The intake of this canal was washed out at 8.40 a. m. January 17, 1916. No water was diverted through it during the rest of the month. Regulation.— Water is stored on Bear Creek at Bear Valley reserv<»r. SANTA ANA RIVER AT SAN BERNARDINO, CAL. Location.— At Salt Lake Street Bridge (E Street), San Bernardino, San Bernardino County. Maximum discharge in January, 1916.— Mr. H. B. Andrews, Riverside Water Co., who measured cross section and slope, from high- water marks which he observed U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 426 PLATE XVI -^•^f.^.ir^'i 5^*^ ~4iwr I. GAGING STATION ON SANTA ANA RIVER NEAR MENTONE, AFTER FLOOD OF JANUARY, 1916. B. VIEW ACROSS CHANNEL OF SAN GABRIEL RIVER AT MOUTH OF CANYON. NEAR AZUSA. AFTER FLOOD OF JANUARY, 1916. U. 6. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 428 PLATE XVII A. VIEW UPSTREAM ON SAN JACINTO RIVER NEAR ELSINORE, AFTER FLOOD OF JANUARY, 1916. B. VIEW EASTWARD ALONG f:OR":"H i^OP.E 0- ELSir.'ORE LAKE, 'vlARCi FLOOD RUN-OFP. 69 during the storm of January 17, haa estimated the discharge as follows: Area, 2,020 square feet; wet perimeter, 251 feet; slope, 0.006; discharge, 40,000 second- feet. The high-water marks on January 27 were practically the same as for Jan- uary 17. The following discharge measurements at Salt Lake Street Bridge, furnished by Riverside Water Co., include San Timoteo Creek and Redlands Wash, but do not show diversions by Gage canal at Sterling Street, Discharge Tneamrements of Santa Ana River at San Bernardino, Cal., during January, 1916. [Made by H. B, Andrews.] Date. Dis- 1 Time of charge, measurement. Date. Dis- charge. Time of measurement. Jan 6 Sec-ft. 127 1,106 3.50 p. m. 4.15 p. m. Jan.22 Sec-ft. 730 3,725 2.15 p. m. 20 28 12.35 p. m. LYTLE CREEK AT SAN BERNARDINO, CAL. The following table was compiled from a blue-print bydrograph furnished by J. A. Sourwine, county engineer. This hydrograph was determined from measurements of East and West channels of Lytle Creek. The West channel was measured at the new Fourth Street Bridge until it went out at 8.05 a. m. January 18. Later measure- ments were made at the Atchison, Topeka & Santa Fe Railway bridge, at North Colton. The East chaimel was measured at the old Fourth Street Bridge until about 9 a. m. January 18, and later at Mount Vernon Avenue Bridge. The discharge record given in the table was taken from the hydrograph at points where there was a change in curvature. A planimeter was used to determine mean daily discharge. Discharge, in second-feet, of Lyile Creel: at San Bernardino, Cal., for January, 1916. Time. Dis- charge. Mean daily discharge. Date. East channel. West channel. Total. Jan. 16 10.00 p. m Dry .... 1 I 17 3.00a.m 650 6,200 13,400 6,200 8,500 2,650 8,000 16,000 8,000 2,800 550 350 920 4,320 5,240 7.30 a, m lO.OOa.m 1 12.45 p. m 3.30 p. m ll.OOp.m Jan. 18 5.00 a. m 6,640 9.40a. m 1.00 p. m 4.30 p. m Jan. 19 lO.OOa.m 1 5.00 p. m 1 1 70 SOUTHERN CALIFORNIA FLOODS OF JANUARY, 1916. SAN JACINTO RIVER NEAR SAN JACINTO, CAL. Location.— In sec. 20, T. 5 S., R. 2 E., at Oak Cliff, 1 mile above mouth of North Fork of San Jacinto River and 10 miles southeast of San Jacinto, Riverside County. Drainage area. — 108 square miles (measured on topographic map). Elevation. — About 2,200 feet above sea level. Maximum discharge in January, 1916.— Mr. W. S. Post, consulting engineer, measured cross section and slope at this point and estimated the crest discharge as follows: Area, 2,058 square feet; wet perimeter, 392 feet; hydraulic radius, 5.2; slope, 0.029; discharge, 30,000 second-feet or 278 second-feet per square of drainage area. SAN JACINTO RIVER NEAR ELSINORE. CAL. Location.— Near center of sec. 9, T. 6 S., R. 4 W., at A. T. & S. F. Ry. bridge at Elsinore Junction, about 1| miles above junction with Elsinore Lake (low- water stage), and 1^ miles southeast of Elsinore, Riverside County. Drainage area. — 718 square miles (measured on topographic maps). Elevation. — About 1,250 feet above sea level. Records available. — January 1 to 31, 1916. Gage. — Vertical staff fastened to trestle bent of railway bridge near left bank; read daily. Discharge measurements. — ^Made from railway bridge or by wading. Channel and control. — Composed of gravel and small boulders; fairly permanent. Maximum discharge in January, 1916. — Measurements of cross section and slope were made March 9 in the canyon about three-fourths mile above gaging station at railway bridge. The channel at this point is composed of sand and gravel with a few small boulders and is straight. Along the banks of the low- water channel there are small bushes and a few trees. There is but one channel at all stages and the high-water banks are clean (PI. XVII, A). The slope of the water surface at maximum stage was determined for a distance of 1,150 feet. The crest discharge has been computed as follows: Width, 290 feet; wet perimeter, 295 feet; area, 1,730 square feet; hydraulic radius, 5.9; slope of water surface (flood stage), 0.0033. If the value of n in Kutter's formula is assumed as 0.035, the discharge is 14,000 second-feet, or 195 second-feet per square mile of drainage area (drainage area at this point, 717 square miles measured on topographic maps). This discharge occurred January 28 at 11 a. m., gage height 19.0 feet. Accuracy. — Gage height record affected by backwater from Elsinore Lake beginning January 30. Rating curv^e defined by two medium-stage measurements and maximum of flood discharge computed from cross-section and slope. Grage read once a day to hundredths feet. Results fair. Daily discharge, in second-feet, of San Jacinto River near Elsinore, Cal.,for January, 1916. Date. Dis- charge. Date. Dis- charge. Date. Dis- charge. Date. Dis- charge. Jan.l 2 Jan. 9 3 Jan. 17 730 Jan. 25 730 2 2 10 3 18 830 26 580 3 2 11 3 19 1,750 27 1,010 4 2 12 2 20 6,800 28 14,000 5 2 13 2 21 1,750 29 6,800 6 2 14 2 22 1,010 30 1,750 7 2 15 2 23 580 31 1,350 8 2 16 2 24 680 Total runK)ff for month{§^^-i^^^ -;j-- ----;;;;;;;;; ^ FLOOD RUN-OFF. 71 Discharge measurements of San Jacinto River near Elsinore, Cat., during January, 1916. [Made by F. C. Ebert.[ Date. Gage heigit. Db- charge. Jan 25 Feet. 10.40 10.32 Sec.-ft. 680 26 651 HISTORY OF ELSINORE LAKE.i Apparently the earliest specific reference to the amount of water in Elsinore Lake is contained in the notes of a traveler through southern California about 1810, who mentions ''Laguna Grande," the original Mexican name for the lake, as being little more than a swamp about a mile long. For the period between that time and 1862 data as to its rise and fall are not available, but in 1862 it was very high and prob- ably overflowed. During the succeeding dry period, especially dur- ing the years 1866 and 1867, when practically no rain fell on the drain- age area tributary to the lake, it receded very rapidly but was full again in 1872 and overflowed down its outlet through Temescal Canyon. After this it again evaporated to a level probably as low as it has ever been since, but the great rains of the winter of 1883-84 filled it to overflowing in three weeks. Americans had settled around it by this time and their descriptions of conditions say that large willow trees surrounding the low-water shore line were of such size that they must have been thirty or more years old. The rainfall in the next ten years was excessive, and the lake stayed high and overflowed naturally during three or four years of the decade. It was purchased by the Temescal Water Co. for the irrigation of lands at Corona, Cal., and its outlet channel was deep- ened, permitting gravity flow to Corona for a year or more after the lake level had sunk below the elevation of its outlet. As the surface still receded a pumping plant was installed and the water was raised a maximum of about 10 feet and then flowed down the natural channel of Temescal Canyon. Pumping was continued a couple of seasons, but the concentration of salts in the lake, due to the evaporation and low rainfall, soon made the water imfit for irrigation. After 1893 the water level sank almost continuously for nearly ten years, with, of course, a shght rise every winter. The heavier precip- itation, beginning in 1903, gradually filled the lake to about half the depth between its minimum level since 1883 and its high level or overflow point. The flood of January, 1916, rapidly raised the level, to overflowing, although the run-off from its drainage area into the lake appears to have been considerably less than that of the wet years of 1883-84 and 1888-89. (See PI. XVII, B.) » Prepared by Francis R. Schanck, assistant inspector of irrigation, United States Indian Office, Los Angeles, Cal. 72 SOUTHERN CALIFORNIA FLOODS OF JANUARY, 1916. The fact that large trees were growing 20 feet or more below the high-water level when the lake filled in 1883-84 indicates that the high water of the sixties and seventies must have been of very short duration. The stumps of the trees were still visible in 1888 and 1889 many hundred feet from shore, but by the time the lake receded in the middle nineties these had disappeared. ELSINORE LAKE AT ELSINORE, CAL. Location, — In La Laguna grant at outlet of lake at Elsinore, Riverside County. Gage. — Vertical staff installed December 1, 1915; datum 1,237.20 feet above sea level. The water surface rose above this gage and a new staff was installed January 25, 1916; datum 1,237.53 feet. This gage was flooded and the observer installed a temporary staff on January 30, 1916, at approximately the same datum, but before it could be referred to previous datum it also was flooded. Daily elevation, in feet above sea level, of Elsinore Lake at Elsinore, Cal.,for 1916. January^ Date. Eleva- tion. Date. Eleva- tion. Date. Eleva- tion. Date. Eleva- tion. Jan. 1 2 3 4 5 6 7 8 1,245.4 1,245.3 1,245.3 1,245.3 1,245.3 1,245.3 1,245.3 1,245.3 9 10 11 12 13 14 15 16 1,245.4 1,245.4 1,245.4 1,245.4 1,245.4 1,245.4 1,245.4 1,245.4 17 18 19 20 21 22 23 1,246.7 1,247.2 1,248.7 1,250.2 1,251.2 1,252.2 1,252.7 24 25 26 27 28 29 30 1,252.9 1,253.2 1,254.0 1.254.5 1,255.5 1.257.5 1,258.5 SOTTTH FORE OF SAN JACINTO RFTER AT HEMET RESERVOIR, NEAR SAN JACINTO, CAL. Location. — The dam is in sec. 7, T. 6 S., R. 3 E., below Hemet Valley, about 6 miles above mouth of South Fork of San Jacinto River, and 17 miles southeast of San Jacinto, Riverside County. Drainage area. — 65.8 square miles (at dam; measured on topographic map). Elevation. — About 4,350 feet above sea level. Discharge, — The following table, computed by Mr. W. S. Post, consulting engineer, shows the run-off into Hemet reservoir. Gage height, in feet, and discharge, in second-feet, of South ForTc of San Jacinto River at Hemet reservoir, near San Jacinto, Cal., for January ^ 1916. Instan- Instan- Reser- taneous Mean Reser- taneous Mean Date. Time. voir gage dis- charge daily dis-' Date. Time. voir gage dis- charge daily dis- height. into reservoir. charge. height. into reservoir. charge. Tan. 14 8 a.m. 116.65 22 54 22 8 a. m. 122.5 146 146 15 8 a. m. 116.88 39 42 23 8 a. m. 122.5 146 146 16 8 a.m. 117. 17 137 164 24 8 a. m. 122.5 162 176 17 2 p. m. 119. 17 2,810 1,450 25 8 a.m. 122.67 228 190 6 p. m. 124.5 3,200 26 8 a.m. 122.67 212 212 12 p. m. 8 a. m. 8 p. m. 125.83 1,440 822 930 27 8 am. a 122, 67 1,710 9,550 2,460 5,070 18 124.5 123.67 754 28 4 p. m. 8 a. m. 128.0 125.0 2,880 12 p. m. 123.5 748 29 8 a. m. 123.92 1,300 1,390 19 12 p. m. a 122. 67 88 412 30 8 a. m. 123.83 1,180 980 20 8 a. m. 122.5 100 126 31 8 a. m. 122.92 260 349 21 8 a. m. 122.5 146 146 a Interpolated. Total run-off ^or period{^f|*^^^-;i-^ ---;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;- 29^^00 NoTB.— Table sunmiarizes the detailed computations, based on notes furnished by the water company and covering stage of reservoir, spillway discharge, gate leakage, and other conditions. FLOOD RUN-OFF. 73 SAN GABRIEL RIVER BASIN. GENERAL FEATURES. San Gabriel River is one of the three large streams traversing the valley of southern California. Its drainage basin lies wholly in Los Angeles County west of the Santa Ana basin and east of the Los Angeles basin and stretches from the crest of the Sierra Madre to the Pacific, a distance of about 50 miles. Its total drainage area is approximately 700 square miles, about one-third of which consists of mountain slopes, which contribute practically all of the run-off except in heavy storms. The remaining two-thirds is embraced in the San Gabriel Valley at the base of the mountains and in the coastal plain southeast of the city of Los Angeles. The mountainous part of the basin is somewhat rectangular. Its length east and west is about 25 miles, and its width about 10 miles. It hes on the southern slope of the Sierra Madre opposite the basins of Big and Little Rock creeks at the north and on the southern slope of the San Gabriel Range, through which the river breaks near Azusa and enters the San Gabriel Valley. The main stream is formed by the junction of two principal forks, one from the north and east and the other from the west. Each of the branches receives many tributaries from the crests of the sm*- rounding ranges. The headwaters come from the western slope of San Antonio Peak (Old Baldy), altitude 10,080 feet, and from the southern slope of other high peaks at the north, such as North Baldy and IsHp mountains. The west fork drains the northern slope of Mount Wilson, the eastern and northern slopes of San Gabriel Peak, and a portion of the southern slopes of the main range to the north. It joins the main stream about 8 miles above the mouth of the can- yon. The general course of the stream is southwest ward. After leaving the mountains it traverses San Gabriel Valley in a wide wash of sand, gravel, and boulders, then breaks through the range of foot- hills separating San Gabriel Valley from the coastal plain at a point called The Narrows, about 5 miles northwest of Whittier, and enters the coastal plain, across which it flows to its mouth in Alamitos Bay, a few miles east of Long Beach. The total length of the stream is about 65 or 70 miles. The principal tributaries of San Gabriel River are Fish Fork and Cattle Creek from the east, and Iron and West forks from the west. Altitudes in San Gabriel basin range from 20 to 200 feet on the Coastal Plain from 200 to 900 feet in San Gabriel Valley, and from 1,000 to 10,000 feet in the mountains. The range of foothills near Whittier has an altitude of about 1,250 feet. The topography is rough and rugged in the mountains, especially in the upper part, where deep and harrow canyons exist. The geologic formation is 74 SOUTHERN CALIFORNIA FLOODS OF JANUARY, 1916. granitic, with a light soil covering. The San Gabriel Valley is more or less roUing and is composed of granitic wash from the mountains. The basin is rather poorly forested, having a sparse timber growth on the higher slopes and brush with some scattered timber on the middle and lower elevations. The mean aimual precipitation in this basin ranges from 15 to 20 inches in the valley area, and from 20 to 40 inches in the mountains. It occurs almost entirely as rain except on the higher peaks, where snow falls during the winter. On the northern slopes snow remains for several weeks. SAN GABRIEL RIVER NEAR AZUSA, CAX. Location. — In the NW. \ sec. 23, T. 1 N., K. 10 W., near road crossing at mouth of canyon, about half a mile above the Pacific Light & Power Corporation's power house and 2 miles north of Azusa, Los Angeles County. Drainage area. — 222 square miles. Elevation. — ^About 750 feet above sea level. Records available. — 1894 to January 31, 1916. Gage. — Staff were fastened to rock point on left bank about 200 feet above ford, read daily; oftener during floods. Gage used January 2 to 8 and 12 to 16, 1916, is on left bank about 600 feet below ford at an independent datum. Discharge measurements. — Made from cable 1,000 feet above ford or by wading near gage. The float measurements on January 17 and 18, 1916, were made just below gage. The cross-section for these measurements, secured March 8, 1916, was taken 145 feet below regular gage (PI. XVI, B, p. 68). Channel and control. — Composed of gravel and boulders; shifts during high water. Extremes op discharge. — 1894-1915: Maximum stage recorded, 11.7 feet Feb- ruary 20, 1914 (discharge, 18,100 second-feet); minimum stage, dry for several months during each year. Maximum discharge in January, 1916. — The crest of the flood occurred at 7 a. m., January 18; gage height, 12.0 feet (discharge, 40,000 second-feet). Diversions. — The power canal of the Pacific Light & Power Corporation heads about 5 miles above the station. No water in this canal from afternoon of Jan- uary 17 to the morning of January 19, as the intake was closed by drift. Regulation. — None. Accuracy. — Kesults considered good for January, 1916. Bating curves for extreme high water are defined by the float measurements made January 17 and 18. A coeflicient of 0.80 was used to reduce float velocities to mean velocities. There was doubtless a fill in the channel after the crest of the flood on January 18 and hence the areas for the float measurements are probably low. Discharge measurements of San Gabriel River near Azusa, Cal.,for January, 1916. [Made by F. C. Ebert.] Date. heigtTt. Dis- charge. Jan. 3 Feet. a 1.82 a 1.62 a 2. 03 a 1.88 Sec.-ft. 63 39 107 76 4 12 13 Date. Jan. 15 17 18. 19. Gage Dis- height. charge. Feet. O2.08 10.30 11.50 7.38 Sec.-ft. 117 618,400 632,400 4,300 Date. Jan. 19 20. 21. 24. Gage height. Feet. 7.10 6.62 6.34 5.80 Dis- charge. Sec.-ft. 3,750 2,380 1,570 848 o Gage below ford read. 6 Float measurements. FLOOD RUN-OFF. 75 Combined daily discharge, in second-feet, of San Gabriel River and Pacific Light 6: Power Corporation's canal near Aziisa, Cat., for January, 1916. Date. Dis- charge. Date. Dis- charge. Date. • Dis- charge. Date. Dis- charge. Jan. 1 63 9 480 Jan. 17 17.100 Jan. 25 840 2 93 1 10 820 18 22.300 1 26 700 3 159 11 480 19 3,980 27 7,940 4 117 i 12 190 20 2,450 28 4.290 5 179 13 159 91 1,650 29 2.240 6 142. 14 135 22 1,410 30 2.080 7 117 15 215 23 1,250 31 1,790 8 102 16 179 24 928 Total runoff for month{5^^--i^-^^^v^---- Note.— Water began flowing in river at gaging station on Jan. 2; discharge Jan. 17 and 18 computed firom several gage readings. LOS ANGELES RIVER BASIN. GENERAL FEATURES. Lo9 Angeles River is formed by Tujunga, Pacoima, and other small creeks whose sources He in the Sierra Madre northeast of the city of Los Angeles. These streams leave the moimtains at a point about 25 miles above the city and enter the comparatively flat country of the San Fernando Valley, where, except at times of excessive flood, the waters disappear in the sand and gravel washes. At the lower end of this valley is a secondary range of hills, extending from east to west, and bed rock obstruction forces the watei-s to the surface to form what is kno\vn as Los Angeles River. Below this point the river flows through the flat country of the Los Angeles Valley and enters the Pacific near the to\\Ti of Long Beach. At the city of Los Angeles it is joined by AiToyo Seco. This stream issues from the mountains on the west side of Pasadena Mesa, and passes through an opening in a granite spur known as Devils Gate. Between the point where it leaves the mountain and Devils Gate lies a broad river bot- tom, 2 miles long, composed of coarse material, into which the water sinks rapidly. In passing over this material the volume of flood water is diminished. LOS ANGELES RIVER AT LOS ANGELES, CAL.> Los Angeles River was measured at the bridge near the old pigeon farm above jmiction with Arroyo Seco. The discharge at 11 a. m. January 19, 1916, was 1,308 second-feet. The maximum height of the flood during the storm was ascertained from an eye \\atness and from marks on the bank, as 4 feet higher than the stage of the river at the time the measurement was made. A velocity of 11.0 feet per second was used for computing the probable maximum discharge. The estimated maximum flow for the stream at this point was 7,268 second-feet. Lippincott, J. B., memorandum concerning the flooOa of Jan. 17 and 18, 1916. 76 SOUTHERN CALIFORNIA FLOODS OF JANUARY, 1916. The following is a summary of measurements made January 18, 1916, for the flood flow between Dominguez Junction and Cerritos, of the water entering the Los Angeles and Long Beach harbors:^ Second-feet. Main Cerritos bridge 22, 873 Cota bridge (first opening to the west) 1, 816 At pole No. 1006 (second opening) : 676 Bridge No. 1463 1, 057 Bridge No. 1450 978 Bridge No. 1433 3, 240 Bridge No. 1418 233 Compton Creek 240 Total 31, 113 Practically half the flow was going to the east into the Long Beach Harbor and, as near as could be determined from the obser- vations, half to the west into Wilmington Harbor. It is considered that the 1916 flood at this point was as great in volimae as in 1914 and that it lasted longer. ARROYO SECO NEAR PASADENA, CAL. Location. — Near south line of sec. 30, T. 2 N., R. 12 W. (unsurveyed), just below trail crossing at forest ranger's station in Angeles National Forest, about 3 miles above Devils Gate, li miles above mouth of Millard Canyon, and 5J miles north- east of Pasadena, Los Angeles County. Drainage area. — 16.4 square miles (measured on topographic maps). Elevation. — About 1,450 feet above sea level. Records available. — December 1, 1910, to January, 1916. Gage. — Staff fastened to an alder on right bank 300 feet southeast of ranger's station. Discharge measurements. — Made by wading below gage or from foot log. Channel and control. — Composed of solid rock, gravel, and boulders; slightly shifting during high water. Extremes op discharge. — 1910-1915: Maximum stage recorded, 12.5 feet February 20, 1914 (discharge, 5,630 second-feet); minimum stage, below gage September 12 to 23, 1913 (discharge estimate, 0.1 second-foot). Maximum discharge in January, 1916. — Crest of flood occurred at 9.30 a. m. January 17; gage height, 9.3 feet; discharge, 3,150 second-feet, or 192 second-feet per square mile. Accuracy. — Gage read only 5 days in January. The high-water extension of the rating curve is based on measurement of slope and cross section of the channel. Curve well defined for medium and low stages. Discharge measurements of Arroyo Seco near Pasadena, Cal., during January, 1916. [Made by F. C. Ebert.] Date. Gage height. Dis- charge. Jan. 12 Fut. 3.55 4.18 Sec.-ft. 14 22 64 1 Lippincott, J. B., memoranda concerning the floods of Jan. 17 and 18, 1916. FLOOD EUN-OFF. 77 Mean daily gage height, in feet, and discharge, in second-feet, of Arroyo Seco near Pasadena, Cal., for January, 1916. Date. Gage height. Dis- charge. Date. Gage height. Dis- charge. Jan 17 7.65 4.14 4.04 o 1,930 ! 58 42 Jan. 24 4.1 •4.18 51 22 25 65 23 a Maximum discharge Jan., 1916, see station description. ARROYO SECO > AT LOS ANGELES, CAL. On January 19, 1916, the flood flow of the Arroyo Seco was meas- ured at Avenue 20 Bridge in Los Angeles. The peak of the flood had passed. Soundings were made from the bridge at intervals of 5 feet. The velocity was ascertained by means of floats and found to be 6.0 feet per second. The discharge at 9.30 a. m. January 19, 1916, was 737 second-feet. From the statement of an eye witness and from water marks on the banks it was found that at the crest of the flood on the preceding days the water had been 4 feet higher than at the time of measurement. Accordingly, a section was com- puted for this higher level. The velocity at the higher stage was estimated to be 11.0 feet per second, which gives a maximum dis- charge for the storm at this point of 6,215 second-feet. SANTA CLARA RIVER BASIN. GENERAL FEATURES. Santa Clara River has its source in Soledad Canyon in the north- central part of Los Angeles County. Its general course is westward, and it enters the Pacific Ocean about 3 miles southeast of Ventura. The principal tributaries are Castac, Piru, Sespe, and Santa Paula creeks, which enter from the north. During the low-water period the channels of these streams are usually dry at their junction with the main stream. For the lower 40 miles of its course the channel of Santa Clara River is broad and sandy. During the rainy season it is subject to very sudden and severe floods while for the remainder of the year the channel is practically dry. SESPE CREEK NEAR SESPE, CAL. Location. — At Bradfields Camp, in Santa Barbara National Forest, three-fourths of a mile below mouth of West Fork of Sespe Creek, A\ miles above intake of Fill- more canal, and about 6^ miles northwest of Sespe, Ventura County Drainage area. — 216 square miles (measured by Ralph Bennett, consulting engineer). Elevation.— About 1,350 feet above sea level. Gage. — Painted on large boulder and on rock cliff on left bank. Discharge measurements. — Made from cable 250 feet above gage or by wading. 1 Lippincott, J. B., memoranda concerning the floods of Jan. 17 and IS, 1916. 78 SOUTHERN CALIFORNIA FLOODS OF JANUARY, 1916. Channel and control. — Gravel and large boulders; fairly permanent. Maximum discharge in January, 1916. — The maximum stage reported was 18.7 feet (discharge 18,600 second-feet) on January 17 (time not given). Accuracy. — Results considered good. Discharge measurements made after January 17 show that the high water caused a small amount of scour in the channel. Rating curves well defined. Cooperation.— The gage-height record and discharge measurements were furnished by Sespe Light & Power Co. Discharge measurements of Sespe Creek near Sespe, Cal., for January, 1916. [Made by G. H. Killgore.] Date. height. Dis- charge. 1 Date. Gage height. Dis- charge. Date. Gage height. Dis- charge. Jan. 2 Feet. 7.60 6.70 8.90 292 1,320 Jan 17... . Feet. 15.90 18.70 16.90 Sec.-ft. 10,100 17,400 13,700 Jan 19 Feet. 9.20 7.60 12.90 Sec.-ft. 1,550 678 o4,690 3 17 21 4 18 27 a Float measurement; coeflBcient of 0.85 used to reduce surface velocities to mean velocities. Mean daily discharge, in second-feet, of Sespe Creek near Sespe, Cal., for January, 1916. Date. Dis- charge. Date. Dis- charge. Date. Dis- charge. Date. Dis- charge. Jan.l 46 1 Jan. 9 850 Jan. 17 8,100 Jan. 25 360 2 605 1 10 440 18 11,400 1 26 345 3 560 ! 11 205 19 2,320 1 27 6,500 4 960 12 144 20 1,060 I 28 1,360 5 184 13 119 21 615 29 900 6 144 14 480 22 495 30 705 7 110 15 228 23 390 31 595 8 106 16 253 24 375 Totalrun-ofi for month{5^p^{f?^-^^^^--^^^-g 81,200 7.04 INDEX. Page. Acknowledgments for aid 8-9 Anaheim Union Water Co., loss to, from flood 30 Arroyo Seco at Los Angeles 77 near Pasadena 76 Atchison, Topeka & Santa Fe Railway Co., loss to, from flood 31 Azusa, San Gabriel River near 74-75 San Gabriel River near, after flood, plate showing 68 Bernardo, San Dieguito River near 58-59 Bonsall, Moosa Canyon Creek near 66 San Luis Rey River at 64-65 Boulder Creek at Cuyamaca reservoir near Julian 54 Bowen, Edward R., cited 39 Bridges, highway, damage to, by flood 32-33 Campbell, A., cited 35-36 Campo, precipitation at, rate of 21-22 Canfield ranch, February 21, 1916, plate showing 30 Canterini, Edward, on preceding floods 39 Capitan Grande dam site after flood, plate showing 47 San Diego River at 52 Carroll dam site, San Dieguito River at, after flood, plate showing 59 Cottonwood Creek at Morena reservoir 42-43 Cottonwood Creek basin, description of 41-42 Crest discharges of streams for January, 1916. . 22-23 Cromwell, George, cited 56 Cuyamaca Peak, elevation of 50 Cuyamaca reservoir, B oulder Creek at 54-55 condition of, during the flood 26-27 Cuyamaca Water Co., loss to, from flood 29 Damage from flood, summary of 7-8, 27 Dehesa, Sweetwater River near 47-48 Descanso, Sweetwater River near 46-47 D oyle. Father, on preceding floods 39 Ellis, C. H.,sr., on preceding floods 36 Elsinore, San Jacinto River near 70-71 San Jacinto River near, after flood, plate showing 69 Elsinore Lake at Elsinore 72 history of 71-72 north shore of, plate showing 69 Engineering Record cited 24,26 Escondido Mutual Water Co., loss to, from flood 30 Fenton-Sumption-Bames Co., loss to, from flood 34 Femold, F. L., on a preceding flood 39 Floods, preceding, rex;ords of 35-40 Foster, San Vicente Creek at 55 San Vicente Creek at, after flood, plate showing 47 Gaging stations, map showing In pocket. Gregg, William S., cited 36-37 Guinn, J. M., cited 36 Hawgood, H., on preceding floods 40 Highways, damage to, by flood 32-33 Hubbard, P. F., on preceding floods 38-39 Indian reservations, damage to, by flood 34 Jamacho, Sweetwater River near 48 Jamul Creek near Otay 45 near Otay after flood, plate showing 46 Jamul Creek basin, de5<7ription of 43 Page. Julian, Boulder Creek near 54-65 Lake Hemet Water Co., loss to, from flood. . 30 Lakeside, San Diego River at, after flood, plate showing 53 San Diego River near 50-51 Land, farm, damage to, from flood 28 Life, loss of, from flood 27 Long Beach harbor, damage to, by flood 34-35 Los Angeles, precipitation at, daily, for maxi- mum months 22 precipitation at, 1877-1916, record of 19 rate of 21 Los Angeles & Salt Lake Railroad Co. , loss to, fromflood 31 Los Angeles & San Diego Beach Railway Co., loss to, from flood 32 Los Angeles harbor, damage to, by flood 34 Los Angeles River at Los Angeles 75-76 preceding floods on 40 Los Angeles River basin, description of 75 gaging-station records in 75-77 Lower Otay reservoir after failure of dam, plateshowing 24 failure of dam at 25-26 Otay River at 44 storage in, for January, 1916 45 Lytic Creek at San Bernardino 69 Mentone, Santa Ana River near 68 Santa Ana River near, after flood, plate showing 68 Mesa Grande, San Luis Rey River near 61-62 Santa Ysabel Creek near 56-57 Mission dam, San Diego River at, after flood, plate showing 52 Mission Valley, San Diego River, after flood, plateshowing 52 San Luis Rey River, in 1915, plate show- ing 28 February 21, 1916, plate showing 28 view across, after flood 29 Moosa Canyon Creek near Bonsall 66 Morena reservoir, condition of, during the flood 24 Cottonwood Creek at 42-43 MulhoUand, William, on preceding floods. ... 40 Nellie, San Luis Rey River near 62-63 Oceanside, debris on beach at, plate showing . 32 San Luis Rey River at 65-66 Otay, Jamul Creek near 45 Otay River after failure of Lower Otay, dam, plateshowing 24 at Lower Otay reservoir 44-45 Otay River basin, description of 43 flood run-off in 43-45 Pacific Electric Railway Co., loss to, from flood 32 Pacific Light & Power Corporation, loss to, fromflood 30 Pala, highway bridge at, before flood, plate showing 33 highway bridge at, wreck of, after flood, plate showing 33 San Luis Rey River at and near 63-64 Power plants, damage to, by flood 30-31 Precipitation, at Los Angeles, 1877-1916, record of 19 79 80 INDEX. Page. Precipitation at Los Angeles, daily, for maxi- mum months, record of 22 at San Diego, lSoO-191G, record of 17-18 daily, for maximum months, record of 22 at Santa Barbara, 1867-1916, record of. . . . 20 for January, 1916, records of 11, 12-16 intensity of 20-22 stations for recording, map showing. .In pocket. Property, miscellaneous, damage to, by flood. 34-35 municipal, damage to, by flood 28-29 See also Water supplies. Railroads, damage to, by flood 31-52 Rainfall. See Precipitation. Ramona, Santa Maria Creek near 59-60 Santa Maria Creek near, in 1917, plate showing 59 • Santa Ysabel Creek near 57-58 Reservoirs, condition of, during the flood 24-27 Riverside Water Co., loss to, from flood Run-off from flood, collection of measure- ments on Run-off of streams for January, 1916 San Antonio Peak, altitude of San Bernardino, Ljrtle Creek at San Diego, precipitation at, daily, for maxi- mum months 30 40^1 24 73 22 precipitation at, 1850-1916, record of 17-18 rate of 21 Switzer Canyon at 56 water supply of, damage to, by flood 29 San Diego & Arizona Railway Co., loss to, from flood 32 San Diego & Southeastern Railway Co., loss to, from flood 32 San Diego Consolidated Gas & Electric Co.; loss to, from flood 34 San Diego River atCapitan Grande damsite, near Lakeside - 52 after flood, plate showing 47 at diverting dam near Lakeside 50-51 at Lakeside after flood, plate sho-ning — 53 at Mission dam after flood, plate sho\\ing . 52 at Mission Valley after flood, plate show- ing 52 at San Diego 53-54 after flood, plate showing 31 near Santee 52-53 preceding floods on 37-38 San Diego River basin, description of 49-50 gaging-station records in 50-56 San Dieguito River at Carroll dam site after flood, plate showing 59 near Bernardo 58-59 San Dieguito River basin, description of 56 gaging-station records in 56-60 San Gabriel River near Azusa 74-75 near Azusa after flood, plate showing 68 preceding floods on 40 San Gabriel River basin, description of 73-74 gaging-station records in 74-75 San Jacinto River near Elsinore 70-71 near Elsinore after flood, plate showing. . 69 near San Jacinto 70 South Fork of, at Hemet reservoir 72 San Luis Rey River at Bonsall 64-65 at Mission Valley, in 1915, plate showing. 28 after flood, plates showing 28, 29 San Luis Rey River at mouth of Moosa Can- yon Creek after flood, plate show- ing 29 at Oceanside 65-66 delta builtup by, after flood, plateshowing 32 from mouth after flood, plate showing. . . 32 near Mesa Grande 61-62 near Nellie 62-63 near Pala 63-64 preceding floods on 38-39 San Luis Rey River basin, description of 61 gaging-station records in 61-62 San Vicente Creek at Foster 55 at Foster after flood, plate showing 47 Santa Ana River at San Bernardino 68-69 near Mentone 6 after flood, plate showing 68 Santa Ana River basin, description of 67-68 gaging-station records in 68-72 Santa Barbara, precipitation at, 1867-1916, record of 20 Santa Clara River basin, description of 77 gaging-station records in 77-78 Santa Maria Creek near Ramona 59-60 near Ramona in 1917, plate sho'wing 59 Santa Margarita River after flood, plate show- ing 31 Santa Ysabel Creek near Mesa Grande 56-x'^~ near Mesa Grande after flood, plate show- ing 58 near Ramona 67-^8 after flood, plate showing 58 basin, description of 56 Santee, San Diego River near 52-53 Sespe Creek near Sespe 77-78 Silent, Roy A., cited 25-26 South Coast Land Co., loss to, from flood 29 Southern California Edison Co., loss to, from flood 30-31 Southern Pacific Co., loss to, from flood 31 Southern Sierras Power Co. , loss to , from flood 31 Squirrel Inn, precipitation at, rate. of 21 Storms of January, 1916, description of 10-11 Sweetwater dam after flood, breaks in 26 breaks in, plate showing 25 Sweetwater River at Sweetwater dam 48-49 near Dehesa 47-48 near Descanso 46-47 after flood, plate showing 46 near Jamacho 48 preceding floods on 36-37 basin, description of 45-46 gaging-station records in 46-49 Sweetwater Water Co. , loss to, from flood ... 29 Switzer Canyon at San Diego 56 Swj'caffer, Mrs. Martha, on preceding floods. . 37-38 Telegraph and telephone lines, damage to, by flood 33-34 Temecula Creek, preceding floods on 39 Temescal Water Co., loss to, from flood 30 Tia Juana River, preceding floods on 36 Tia Juana River basin , flood run-off in 4 1-43 United States Geological Survey, loss to, from flood 35 United States Weather Bureau cited 10 Water supplies, damage to, by flood 29-30 Western Salt Co., loss to, from flood 34 Winston ranch, February 21, 1916, plate show- ing 30 GEOLOGICAL SURVEY WATER-SUPPLY PAPER 426 PLATE MAP OF A PART OF SOUTIiEEN CALIFORNIA SHOWING I'RECIPITATION AND (iAGING STAIIONS 6* r-p. r V -'il4# ' ! I ^ Precipitation station Boundaries o PRECIPITATION S -^ / U -X LIBRARY OF CONGRESS 019 953 860 3 \i I. u Mi i I m