THE LIBRARY OF THE UNIVERSITY OF CALIFORNIA DAVIS i STATE OF CALIKORNIA DEPARTMENT OF PUBLIC WORKS DIVISION OF WATER RESOURCES EARL WARREN, Governor C. H. PURCELL, Director of Public Works EDWARD HYATT, State Engineer BULLETIN No. 53 SOUTH COASTAL BASIM INVESTIGATION OVERDRAFT ON GROUND WATER BASINS 1947 Tlltl'd prilltcj ill CALIFORNIA STATE PRINTING OFFICE LIBRARY UNIVERSITY OF CALIFORNIA DAViS BEAUMONT tOUND WATER BASINS ■S UPPER 'SANTA ANA VALLEY S4 47 LEE L 46 COLOVN 49 BEOrOl M N 33*45' ^ 16 CHINO <7 CLAREMONT HCICHTS <6 LIVE OAK 19 POMONA 20 CUCAMONSA 21 a RIALTO 21b COLTON 22 BUNKER HILL 23 LYTLE 24 DEVIL CANYON Ida YUCAtPA iSb BEAUMONT 26 SAN TIMOTEO 27 RIVERSIDE 26 ARLINGTON 29 TEUESCAL 40 LOWER CAJON 41 UPPER CAJON 42 BEAR VALLEY 43 BIG MEADOWS ^44 SEVEN OAKS t.45 RECHE CANYON 46 CAJALCO 117*00' STATE or CALIFORNIA, JEPARTMENT OF PUBLIC WORKS ISION OF WATER RESOURCES :OASTAL BASIN INVESTIG 318 31b 32 33a 33 b 33c 33d 33 e 33f 34 35 36 37 50 WE3T ( WEST { MOLLYS LOS Al MONTE SANTA IRVINi CENTB EAST LA HA YORBA LOS A SANTA SANTI NREA ZSvOOO INVE^ 10 5(»000 32 33 34 35 TABLE OF CONTENTS Pcu/c ackxowled(;mext i"» OKGANIZATIOX ^ FOKKWOUI) J' Chapter I IXTKODl CTIOX 1^ Definition of Overdraft 1 * l*roce(lnre Followed 1'*" Snnimary J'^ Chapter II DKSCRIPTIOX OF SOITH COASTAL BASIN -M Toposi'aphy -] Climate -•' Soils --* Culture -"i" Stream Systems *-•> Los AuL'eles River •>0 '»' San Gabriel River. :vi Santa Ana River 33 Ground Water Basins •">"• Chapter III )— WATER SUPPLY OF SOTTH COASTAL P.ASIX 37 Long-time Mean Period 37 Chapter IV EVATvUATIOX OF OVERDRAFT OR EXCESS 47 Combined Overdraft or Excess .'»! Los Angeles River Ground Water System ."»! San Gabriel River Ground Water System .">1 Chino Basin (iroup .~>2 Santa Ana River Ground Water System .~»2 Chapter V DISCUSSION OF ITEMS IXVOLA'ED IX EVALUATIOX OF OVERDRAFT (h Change in Storage (»7 Precipitation (»1) Mountain and Hill Runoff 71 Import 72 Consumptive Use 74 Export 77 Snrface Outflow 77 Rising Water 78 Snbsurface Outflow 7<> Chapter VI DP^TAILED DISCUSSIOX OF l^ASIXS Sr> Verdugo Basin sr> Inflow S."» Consumptive use S(J Export S7 Surface Outflow 8S Subsurface Outflow SS 0\erdraf^ 81 > (3) # ke^^ y .*"Wf 'S*<^5««W<'' yr\. e>?^> ■^. San Antokio Peak - Ai^ 'K. 27 I 26 T LEGEND ^^ - .^ WATcnSHCO kOUNDaav -Tj/V.^^--. ^115 cost Of noww»TeR - acARiNC axca ^^^■^^^^^ GKOUND WtTC N BAftlM lOUNIURV «M*^^*^^ SUB-AOCA lOUNOARV ■ ••***• *pp«OKiu*TE ftauNo*HY OF pnejsuKE zonc 6 CNOUND WATCH ■A3IN nCfCnCNCE NUMtER I I — > _J uouu- 5Bn Gabriel Dams ft ^j' "^ qCIAREmokit upland ("PLAVA DEL «Y Y?) ^N SOUTH&ATe JB 1^ l,"!^ n^ r' \ \° \ w r CORONA 29 \ 26 \ 25a X;^ -■fV '5^W ".^j el j^ "-^y ^^^^^SliUElU)"*^ /:<* lJ ' ^-^~. f GROUND WATER BASINS UPPER UPPER 5_AN FEfiNANpO VALl^Y SANTA ANA VALLEY SANTA ANA VALLEY 1 San FtRNAHOO II CHIMO 4T UEI LAUt Tl » VENOUOO 30 CUCAUON&A COASTAL PLAIN Si; mlSx)°n ><■ Wt^T COASTAL PLAIM - MORT>« lib WEST COASTAL P1.AIN -JOITTH SAN GABRIEL VALLEY 21 LTTLE .iSS'-aiS'^ t»t> aiAUuoNt Uc SANTA AN* • UPPER CANVOH ]Sr EAJT COASTAL PLAIN PRUSURC II CLENDORa 40 tOWm CAJOM la VORBA LINM 41 UPPIR CAJON J* LOS AH6ELES HARROWS «} RUHE CAMTDH 41 CAJALCO -^a4*oo' -^13*4d' sian- .J4 Los Angeles River ."»(> San Gabriel River .".2 Santa Ana River 33 Ground Water Basins .'>."» Chapter III WATER SUPI*LY OF SOT'TH COASTAL BASIN 37 Jjong-time Mean Period 37 Chapter IV EVALUATION OF OVERDRAFT OR EXCESS 47 (\)mhined Overdraft or Excess .">! Los Angeles River Ground Water System 7\\ San Gabriel River Ground Water System 7\\ Chino Basin Group r»2 Santa Ana River (iround Water System r»2 Chapter V DISCT^SSION OF ITEMS INVOLVED IN EVALFATION OF OVERDRAFT iu Change in Storage (\~ Precipitation Cj) Mountain and Hill Runoff 71 Import 72 Consumptive Use ^iij.'_L_ 74 Export ■_'J__ 77 Surface Outflow 77 Rising Water 7s;; Subsurface Outflow 7<) Chapter VI DETAILED DISCUSSION OF P.ASIXS 8," Verdugo Basin j^,-> Inflow v<7, Consumptive use <^(5 Export S; Surface Outflow v;s; Subsurface Outflow <;;is; Overdraft ~ '^^^ (3) TABLE OF CONTENTS — Continued Page DKTAILKD IHSCISSIOX OF IlASIXSContimird S.in FcniMiido ^^•lll(•y Aicm 9() liiHow 01 liniM.it J>2 (\uisuinpt i\ »• us«' y.» KxpoiT 04 Surf.icc (MitHnw i)4 Excess - 1)^ Siihsiirf:i( (' <)utH«iw 0(» ^^'t'st('nl luil of l{;iyin(Ui(l liasiii Area t)7 Iiirtnw OS Jlistoiical Iiuport Ol> ('oiisuiiiptix (' use 91) Kxpnir 100 Suilacc Outflow 101 . Arroyo Scco 101 Eatoli Cn'ck 102 J5io;i(l\vay. (Iiaiiada and Kuhio ])rains lOo riiincasuriMl 10."> Sul)snifa<«- Ontfiow 104 K(M|nir(>d Lon^i-tiiin' M<'an Import I'nder Present Coiulitions _ 104 lOasttMii I'liit of Kaynntud IJasiii Area 10."i Inflow 10(; Consiiiniii i\ (• use 107 Historical Kxi>ort 107 Surface Outflow 108 Suhsurl.-Kc Outflow 100 Lonjr-tiine M«'an Amount Availal)le for Export . 100 oi t 111 Consumptive ns(> 112 Surface (Milflow ll.'> Excess 1 114 Siilisnrfac «' ()utflow 114 Way Hill Hasiu 115 Inflow ll.~» Import _- 110 ( "onsumpt i\(' use 116 l^xport 117 Surface (Milflow 117 Excess lis Sul)surfa(e (Mitflow llS Foothill IJasiu 110 Inflow 11 1» Impoit 120 ( 'oiisumpl ive use 120 Export 121 Surface Out liow I>uriu- ll-Vear Period 121 Sultsurface (Milflow 122 Loii.i: time Mean Surface Outflow 122 San l>imas I'.asin 12.*» Iiifl<.\v 124 Imi>ori 1J4 ( 'ousuiuiii i\ e use : 12."! 10x1 toil 120 Surface (Mil flow 127 I'^xco-s . _ 12S Sulisurfa(e ()ulflow _. _ 1 2S Spadr.i l'.a>iii •__... ^ -['>*) Inflow _'Jij_-- _ „ l.">0 TABLE OF CONTENTS— Continued 1>ETAILE1> DlSdSSIOX OF HASIXS— ('onrimu'd Import 1-><* Consumptive use l'>() Export 1^1 Surface Outflow 1 i:i2 Overdraft V.\2 Subsurface Outflow IHM Puente Basin 1.'i4 Inflow VU Import V\~t Consumptive use 13r> Surface Outflow VMi Excess VM Subsurface Outflow V\S (Vntral San (labriel Valley Area l.'iS Inflow i:»> Import 141 (Consumptive use 142 Export 14;i Surface Outflow Duiiujr 11-Year Period 144 Subsurface Outflow 144 Ix)ng-time Mean Surface Outflow 14.'i I.a Habra Basin 14<> Inflow 147 Import 147 Consumptive I'se 147 Export 14S Surface Outflow 140 Overdraft 150 Subsurface Outflow l.~>(> liower I^)s Anjreles and San Cabriel Kivers Area ir»l Inflow to Nonpressure Portion of Area ir>:{ Import to Nonpressure Portion of Area ir»4 (Consumptive Pse in Nonpressure Portion of Area ir>r> Exi)ort from Nonpressure Portion of Area lot) Surface Outflow from Nonpressure I'oition of Area iTA'} Extractions from (Central Coastal Pltiin Pressure Area ir)S Overdraft 1^0 Claremont Ileijfhts Basin 1()() Inflow KU Import HU Consumptive I'se 1(J2 Export 1(52 Surface Outflow Mil) Overdraft 1(»4 Subsurface (Outflow Km Live Oak Basin !(>.'» Inflow ^^}i\ Import 107 Consumptive Pse 1G7 Export 1(».S Surface Outflow lOS Excess 1(>1) Subsurface Outflow Kill Pi)mona Basin 170 Inflow 170 Import 171 (yonsumptive Pse 171 Export 172 Surface Outflow 1 17:i Overdraft __-___--__-_ 17:» Subsurface Outflow 174 (5) TABLE OF CONTENTS — Continued Page DKTAILKT) DlSCrSSIOX OF P.ASIXS— Continued Cucnnmnj;;! B.-isiii 175 Inflow ITo Ininort 176 Consumptive T'se 17f> Export 177 Surfju-e Outflow 178 Excess 178 Suhsurfnce Outflow 170 Riiilto Rnsin 180 Inflow 180 Imi)ort 181 Consumptive T'se 181 Export 182 Snrfnce Outflow 18?> Overdnift 184 Sul>surfnce Outflow 18.' T.ower Cnion Bnsin >- 18r» Inflow 180 Consumptive T'se 187 Export 187 Surface Outflow 187 Subsurf.-ice Outflow 188 Lvtle Bjisin 180 Inflow 100 Import 100 Consumptive T'se 101 Historical Export 102 Surface Outflow 102 Su1)surface Outflow 102 Lon^r-timt^ Mean Amount Available for Export 103 Devil Canyon P»asin 104 Inflow 104 Consumi>tive I'se . 105 • Export 100 Surface Outflow 100 Devil Canyon Creek 107 "Waterman Canyon Creek 107 Strawberry Creek 197 Other Sources 108 Subsurface Outflow 108 Yucaipa Basin 100 Inflow 100 Consumptive T'se 200 Export 201 Surface Outflow 201 Overdraft 202 Subsurface Outflow 202 Beaumont Basin 203 Inflow 203 Consnm])ti\e T'se 204 Historical Export 205 Surface Outflow 205 Subsurface OMtfl<»w 205 Lonji-time Mean Amount Available for Export 200 San Timoteo Basin 207 Inflow 208 Imi)ort 208 Consumptive T'se 200 Exi)ort 200 Surface Outflow 210 SubsurfaKI) I)IS('rSSI()X OF HASIXS— Continued Bunker Hill llnsin 211 Inflow 212 Import 218 Consninptive Tse 214 Export 215 Surf.Mce Outflow Duriuj; ll-ve;ir Teriod 21.' Subsurface Outflow 210 Ix)nj;-tiine Mean Surface Outflow 210 Colton-Reche (\in.von Area 21S Inflow 211) Import 211) Consuujptive I'se 220 Export 220 Outflow 221 Riverside-Arliujjtoii Area 222 Infl(.w — 223 Import 22'i Consumptive I'se 224 Export 224 Surface Outflow Durinji 11-year Period 22'> Subsurface Outflctw Durinj; 11-Year I'erio Exi>ort 28« Surface Outflow During' ll-.vcar I'eriow to Santa Ana Narrows Rasin 28(5 Subsurface (Outflow to Spadra l^>asin 287 Risinj; Water Oriffinatiu}; in Cliino Rasin 287 I^»njr-time Averafje Annual Surface Outflow 281) Overdraft 240 Irvine Rasin 241 Inflow 242 Imi)ort 242 Consumptive I'se 248 Export 248 Surface Outfl«»w 244 Overdraft 244 Subsurface Outflow 24r» I^)wer Santa Ana River Area 24(> Inflow to Nonpressure Portion of Area 247 Import to Nonpressure I'ortiou of Area 247 Consumptive Cse in Nonpressure Portion of Area 24S Export from Nonpressure I'ortion of Area 241) Surface Outflow from Nonpressure I'ortion of Area 241) Extractit)ns from East Coastal Plain Pressure Area 250 Subsurface Outflow from East Coastal Plain Pressure Area 251 Overdraft 251 (7) LIST OF TABLES f^ihlr Title Page 1 Ai«';is of ^";^ll«'\ . Hill ;ui Estimated Annual Overdraft or Excess by Basins Vnder Present Con- ditions -"iO ({ Ratios Between Slnu-ter Period Average Annual and oH-year Mean Annual I'recipitation (iO 7 Estimated Averajre Annual Precipitation on Basins 70 5 Estimate 17 Overdraft SI) San PVrnando Valley Area 15 Surface Inflow !>2 1!> Import 08 20 Consumi»tive I'se 0."5 21 Export 04 22 Surface Outflow 05 28 Excess 0(; 24 Subsurface Outflow 07 Western I'nit of Raymond Basin Area 2ri Surface Inflow 00 2H Historical Import 00 27 C»tnsumptive I'se 1(K) 25 Exj.ort 101 20 ~ Surface Outflow 108 ;iO Subsurface Outflow 104 81 Recpiired Imjtort I'nder I'resent Conditions 10."» Eastern I'nit of Raymond Basin Area 82 Surface Inflow _* 1(M{ ?^\ Consumptive I'se 107 84 Historical Export 107 8r. Surface Outflow lOS 8(» Subsurface Outflow 100 87 Amount Available for Export Fnder Present Conditions 110 (Ilendora Basin 88 Surface Inflow HI 3J> Import 112 40 Consumptive I'se 112 41 Surface Outflow 118 42 Excess 114 43 Subsurface Outflow 114 Way Hill Basin 44 Surface Inflow 110 4r» Import 11(> 4({ Consuniptive I'se 117 47 Expoit 117 45 Excess 118 40 Subsurface Outflow 110 Foothill Basin TA\ Surface Inflow 120 r»l Import 120 "►2 Consumittive Ise 121 (8) LIST OF TABLES — Continued 57 }C> Table Title I'dur 58 Export 121 54 Surface Outflow During- 11 year IViiod Vll 55 Subsurface Outflow 122 5() Long-time Mean Surface Outflow 12.'-l San Dimas Basin Surface Inflow 124 Import 125 5i) Consumptive Use 12(5 1)0 Export 127 (51 Surface Outflow 127 G2 Excess 12S {\:\ Subsurface Outflow 121> Spadra Kasin ()4 Surface Inflow 180 ()5 Import 180 (>() Consumptive I'se 181 07 Export 181 (5S Surface Outflow . 182 69 Overdraft 188 70 Subsurface Outflow 1:58 Puente Rasin 71 Surface Inflow 185 72 Import 185 78 Consumi)tive I'se l.'»(; 74 Surface Outflow 187 75 Excess 187 70 Subsurface Outflow l."»,s Central San (ial)riel \'allev Area 77 Inflow " 141 78 Import 142 79 Consumptive Cse 148 50 Export 144 51 Subsurface Outflow 145 82 Long-time Mean Surface Outflow 140 La Habra liasin 88 Surface InHow 147 84 Import 147 85 Consumptixc I'se 14s 80 Export 140 87 Surface Outflow 140 88 Overdraft 150 80 Subsurface Outflow • 151 ]^»wer Los Angeles and San (iabriel Rivers Area tM) Surface Inflow to Xonpressure Portion of Area 154 01 Import to Xonpressure Portion of Area 154 02 Consumptive I'se in Xonpressure Portion of Area 155 03 Export Froui X'onpressure INtrtion of. Area 15(5 04 Surface Outflow From Xonpressnie Porti<»n of Area 15S 05 Difference Retween I'resent and 11-year Average Annual Extractions From Central Coastal PI liu Pressure Area 150 JM> Overdraft KM' Claremont Heights Rasin 97 Surface Inflow 1(51 98 Import l8 101 Surface OutH<»w 104 102 Overdraft H54 108 Subsurface Outflow 1(>5 Live Oak P>asin 104 Surface InHow 10(5 105 ImjMMt R»7 (9) LIST OF TABLES — Continued Table Title Page l(l(» ('((iisuniptivp I'se IGT 107 KxiM.it 108 KIN Surfitc*' OiitHow 1(>K i;;i Kxccss 161) 11(( Sul»siuf:ic»' Oiitrtow -- IG!) Poiuoii.-i li.-isiii in Surface luHow 171 1 lli Import 171 11."! ('«)iisuini>ti\>* I'so 17li 114 KxiM.rt 172 llTi Surfjioe OutHuw 178 M(i Overdraft 174 117 Subsurface Outflow 174 Cueauioiijfa Hasin llN Surface InHow 17(5 11!> Import 17() lljd Consumptive I'se 177 121 Export 177 IHL' Surface Outflow 17.S 12;: Excess 17U 124 Subsurface Outriow 171) Rialt(» liasin 12.". Surface Inflow 181 12(i Import 181 127 ('oiisumi)tive I'se 182 128 Export 182 1251 Surface Outflow 184 i;;(» Overdraft 184 l.'Jl Sul>snrface Outflow 185 Lower Cajon liasin i:;2 Surface Inflow 180 }'.VA ('(»nsumi>tive I'se 187 i:i4 Export 187 l.T. Surface Outflow 1 188 loC. Subsurface Outflow 181) L\ tie liasin i:'.7 Surface Inflow IIM) Kis Import 11)1 i;*.'.t Consumptive I se 101 14(» Historical Export 11)2 141 >ui»suiface Outflow 11)8 142 Amount Available Un- Export Iinler I'resent Couditious 193 Devil Canyon liasin 14:; Surface .Inflow 11)."> 144 Consumpti\e I'se IDO Ur. Export 11)0 I-IC Surface Outflow 11)8 147 Subsurface Outflow 11)8 Vucaipa liasin 145 Surface Inflow 200 141» Consumptive Ise 200 i:^!» Expcut 201 l.'.l Surface Outflow 201 1.'.2 Overdraft 202 ir»:i Subsurface Outflow 202 lU'iUinont liasin 154 Surface Inflow 204 l."»."» Consumpti\e I'se 204 l."»(; Historical Export 205 157 Surface Outflow 205 1.5S Subsurface Outflow 200 l."»l> Aniouui A\ailai)le for Exi)ort I'nder Present Conditions 200 (10) LIST OF TABLES — Continued Title Paye San Tinioteo Basin Surface Inflow -- 2()S Import 20J) Consumptive Use 200 Export 210 Surface Outflow 210 Subsurface Outflow 211 Bunker Hill Basin Inflow 21:J Import 214 Consumptive Use 214 Export 21.'. Surface Outflow During 11-Year Period 210 Subsurface Outflow 21(5 Lons-time Mean Surface Outflow 217 Colton-Reche Canyon Area Surface Inflow 210 Import 210 Consumptive Use 220 Export 221 Outflow 221 Riverside- Arlington Area Surface Inflow 22.*» Import 22a Consumptive Use 224 Export 22.") Surface Outflow During 11-Year Period 22."> Subsurface Outflow During 11-Year Period 220 Long-time Mean Outflow 227 Temescal Basin Surface Inflow 22S Import 220 Consumptive I'se -M) Export - — - 2:iO Surface Outflow 2:il Subsurface Outflow 2:i2 Chino Basin Inflow 2;U Import . 2.*i.'> Consumptive Use 2.H.'> Export 2:iO Sul)surface Outflow to Spadra Basin 2.'i7 Rising Water Originating in Chino Basin 2."'»0 Long-time Mean Surface Outflow 240 Overdraft 241 Irvine Basin Import : 242 Consumptive Use 24.'i Export 244 Surface Outflow 244 Overdraft 245 Sul)surface Outflow 245 Lower Santa Ana River Area Surface Inflow to Xonpressure Portion of Area 247 Import to Xonpressure Portion of Area 248 Consumptive Use in Xonpressure Portion of Area 24S Export From Xonpressure Portion of Area 240 Surface Outflow From Xonpressure Portion of Area 2.'>0 Difference lietween Present and 11-Year Average Annual lOxtractions From East Coastal Plain Pressure Area 251 Overdraft 252 ( 11 ) LIST OF PLATES Follotoiny I'hile Title unye 1 Ke\ to Area Iii\estij;:it»'(l (Frontispiece) 1 2 (Cumulative Deviation From ri.'i-Year Mean Precipitation *>7 :\ Periods of Stream Flow Records — Ix>s Angeles River System .'V.) 4 Periods of Stream Flow Records — -San Gabriel River System 43 ." I'eriods of Stream Flow Records — Santa Ana River System 44 r» IVriods of Stream Flow Records — Streams Flowinj; Direct to (~>cean 4."> 7 Stream (4:iginv: Stations 46 5 Fluctuation of Water Tahle at Wells — San Fernando Valley Area and A'erdujro l*asin .">8 i> Fluctuation of Water Table at Wells— Raymond J^»asin Area r»4 10 Fluctuation of Water Table at AVells — Fastern San (Jabriel Valley Area .">."; n Fluctuation of Water Table at Wells — San (Jabriel and Puente Basins_ T>fi VI Fluctuation of Water Table at Wells— Central Coastal Plain West Half Tu 1?, Fluctuation of Water Table 'at Wells— Central Coastal Plain Fast Half r»S 14 Fluctuation of Water Table at \\'ells — Lytle, Cucamonjja. Rialto and Chino Hasins .">!) 1."» Fluctiiation of Water Table at Wells — P>eaumont. Vucaipa. San Timo- teo, Riverside, Temescal and Arliufjton P>asins (M) 1<) Fluctuation of Water Table at Wells — P>unker Hill and Devil Canyon Basins 61 IT Fluctuation of Water Table at Wells— East Coastal Plaiji 02 15 Fluduatifui of Water Table at Wells— East Coastal Plain (Wi V.) Fluctuation of Water Table at Wells— West Coastal Plain 04 20 Location of Wells at Which AA'ater Table Fluctuations Are Shown 06 21 Lines of Ecpial l*recii)itation — -Mean for .'hJ-Year Peri(Kl SO 22 Relati(»n P»etween Laia nscd as a hasis for the stialtj of overdrafts jjrcsentcd in this bulletin were eoutrihuteel by variojis departments of the federal, countij and eity govermiienls, by flood eo)iiroJ and water districts and bij many companies and individuals. This cooperation, as well as valu(d)Je advice received, is ac'knowledgcd vith thanl's. 13 J ORGANIZATION C. H. PrRC'ELL Director of Public Works Edwaki) Hyatt State Eniiineer A. D. Ed.moxstox Assistant State Eii'^iueer This bulletin was prepared under the direction of GoKDOx Zander Pi-incipdl Hifdraulic Eiujiucer Bv Geok(ji-: B. Gleasox Supervishuj Hydraulic Ei^ginecr Assisted by 11. C. Keua' Senior Hydraulic En«iineer Harvey 0. Baxks Associate Hydraulic Engineer Willia:\[ ].. ]>ERRV Associate Ilydraul J. J. IIeacock Associate Ilydraul E. E. Clark Assistant Ilydraul Leoxard L. LoxcAcRi: Assistant Ilydraul AVillia:\i H. Oversiiixer Assistant Ilydraul XoRMAX J. Taxguay Assistant Ilydraul c Eniiineer c Engineer c Enortion of the excess. This increase in outflow will add to the supply to Main San Gabriel Rasin, and in turn to the outflow from it, and to the supply to Central Coastal J*lain, reducing the overdraft there. Tlius, even in a system of this character, the distribution of overdrafts and excesses is to a degree arbi- trary, but total overdraft on the system is again unaffected by the distribution. A significant change in outflow originating in the ground water of Chino Basin would re(iuire that the water table in the basin be either considerably higher or lower than it has been during the period in which levels have been measured and recorded. For this reason, the group which includes Chino Basin and basins tributary to it is considered separately from the remainder of the Santa Ana River System. All of these basins are considered as falling in the second category, and over- draft or excess is evaluated for each. Within all of the systems or groups herein discussed, the distribution of overdraft depends upon more or less arbitrary assumptions, not only as to subsurface or rising water out- flow, already noted, but also as to interchange of water by other means. This is especially true in the Chino Basin Group, Avhere extensive spread- ing operations in the tributary basins reduce the surface flow to Chino Basin, but make available to it a greater imported supply. So long as these assumptions apply only to interchange of water between basins within the group, they too affect the distribution, but again do not affect total overdraft on the group. 20 DIVISION OF WATER RESOURCES Estimated total auiiiial overdrafts on or excess supply available to the four systems of basins are presented below. Overdrafts or excesses evaluated for individual basins are summarized in Table 5. (inmud Wat«'r System I^os Angeles Uiver sibove the Narrows 2.1. 000 acre-feet excess* San (lahriel River 10,000 acre-feet overdraft Cliino I'.asin (Jroup 21,000 acre-feet overdraft Hemainder of Santa Ana River System 14,000 acre-feet overdraft * Includes water available to Los Angeles Aqueduct in Mono Basin and Owens Valley. See discussion of excess in San l-^ernando Valley Area in Chapter VI. CHAPTER 11. DESCRIPTION OF SOUTH COASTAL BASIN TOPOGRAPHY South Coastal Basin ^ includes about 3,800 square miles of area tribu- tary to Los Angeles, San Gabriel and Santa Ana Rivers,^ and to smaller streams and drains entering the Pacific Ocean along approximately 65 miles of southeasterly trending shore line between Topanga Canyon and Newport Bay, and occupies portions of Los Angeles, Orange, Riverside and San Bernardino Counties, in California, south of the crest of San Gabriel and San Bernardino Mountains. The mountain ranges,^ which occupy the northerly 1,100 square miles of the basin, attain elevations in excess of 10,000 feet at San Antonio Peak in the San Gabriels a short distance west of Cajon Pass, ajid at Mount San Gorgonio, in the San Bernardinos not far from the easterly basin boundary. Each of the ranges is lower in its westerly portions. ^ San Fernando, San Gabriel and Upper Santa Ana Valleys, drained by Los Angeles, San Gabriel and Santa Ana Rivers, respectively, border the south slope of the mountins. South of these valleys a range, intermediate between the high moun- tains and the coast, crosses the area in a southeasterly direction from Santa Monica Mountains to Santa Ana Mountains, both of which form a part of the intermediate range. Santa Monica Mountains reach an elevation of a little more than 2,000 feet. Santiago Peak in the Santa Anas is over 5,000 feet high. San Rafael, Merced and Puente Hills, which lie between, are much lower. The three principal streams cut through the intermediate range at Los Angeles Narrows, Whittier Narrows and Santa Ana Narrows, respectively. At the westerly extremity of San Fernando Valley, Simi Hills extend northerly from Santa Monica Mountains to Santa Susana Mountains, and form the divide between Los Angeles River drainage and that into Santa Clara River, which flows into the ocean far to the west of South Coastal Basin. Betw^een the three inland valleys wide spurs extend northward from the intermediate range, virtually separating the valleys one from the other. Lying northeasterly from Santa Ana Mountains, and separated from it only by the narrow valley of Temescal Creek, a large triangular block of low granitic hills extends to the vicinity of Colton, only about 10 miles from San Bernardino Mountains. The northerly trending crest of this block forms a part of the divide between drainage directly into Santa Ana River, and that into San Jacinto River above Lake Elsinore, which latter area is excluded from discussion in this bulletin. Beyond the northern tip of the granitic block the divide trends a little south 1 "Basin" is used here in its geographic sense. South Coastal Basin includes not only many "ground water basins," but also their tributary nonwaterbearing hill and mountain drainage. A "ground water basin" includes the water-bearing deposits only. 2 Lake Elsinore fills and overflows into Temescal Creek, and thence into Santa Ana River very infrequently. The overflow constitutes so small a part of the inflow that the area tributary to the lake is not included as a part of Santa Ana River drainage. 3 For a more detailed description of these mountains, as well as the rest of the area, see Division of Water Resources Bulletin 45, "South Coastal Basin Investiga- tion — Geology and Ground Water Storage Capacity of Valley Fill," 1934. (21 ) ^1') DIVISION OP^ WATER RESOURCES of east, ])aralleliii«2- San Timoteo Creek to the vicinity of Beaumont. Between Beaumont and the San Bernardino Mountains the boundary crosses Beaumont Plains, northerly alon^- the crest of a flat divide between drainapre into Santa Ana Kiver by way of San Timoteo Creek, and that into Salton Sea. far to the southeast. The Coastal Plain lies between the south face of the intermediate ranjre and the ocean. About midway of the shore line between Topanga Canyon and Newport Bay, San Pedro Hills form the outer end of a promontory jutting- into the ocean. To the west of the.se hills the shore line trends only a little west of north, to the point where it meets the south toe of Santa Monica Mountains. For convenience, this northerly trendiuir shore line is called the AVest Coast. East of San Pedro Hills the trend is first northeast, then chanizes gradually to southeast at Alamitos Bay, and continues in a relatively straight course to its contact with the liilis southeast of XcAvport Bay. This portion is called the South Coast. The southeast boundary of the Coastal Plain follows the divide between drainage into Newport Bay, and that into several relatively small streams which enter the ocean farther south and east. Save for a short distance in the vicinity of El Toro where it crosses a flat saddle, it follows the crest of San Joatjuin Hills. North of the saddle it enters the foothills of Santa Ana ^Mountains. South Coastal Basin as a whole constitutes a distinct hydrologic unit. Natural inflow of water originating outside the area is limited to infre(pient and negligible overflow from Lake Elsinore, and possibly a very small underflow at the few points where the boundary crosses alluvium. The same is true of areas included in or draining into each of the three iidand valleys. The Coastal Plain however is different, in that a considerable part of its supply originates in or passes through the three inland valleys, and is therefore affected by conditions in the A^alleys. The area of mountain, hill and valley land included in each of the four main divisions of South Coastal Basin is shown in Table 1. TABLE I. AREAS OF VALLEY AND FOLDED, AND HILL AND MOUNTAIN LAND IN FOUR MAIN DIVISIONS OF SOUTH COASTAL BASIN (Square Miles) ' I . •*•■■' ' YixWexj and Tribulary lands JUriswn folded lands * Hills Mountains Total San FiTiinndo Valley 201) 74 216 499 San r.ahriel Valley 201 46 334 581 Tpper Santa Ana Valley 670 267 r^'t-i 1,490 C.astal Plain 852 232 138 1,222 Total 1.932 619 1.241 3,792 • Topographically, a large part of the folded area might be classed as hills, but since it is water-bearing it is treated as a unit with valley lands. Topographically, the mountains are steep and rugged, and the hills more gently sloping and rounded. A large part of the Coastal Plain is relatively smooth, with a gentle slope generally at right angles to the shore line. However, adjacent to San Joacjuin Hills on the southeast, and to the intermediate range which borders the plain on the north and northeast, the slope steepens and SOT'TII COASTAL BASIN INVESTKJATIOX 2''\ topojirapliy is more rollinjj. Along' the AVest Coast, low, irrejiulai- sand dnnes form the surface. In San Fernando and San Gabriel Valleys a comparable situation exists. The slopes, which are jxenerally to the south, are a little stee]^er throuii'hout than those on the Coastal Plain, and increase as they approach the mountains to the north. In spite of this increase in slope and some- what roujrher topo«>raphy immediately adjacent to the mountains, chanreat moment. Soils in the eastern portion of the valley nortii of San Jose Hills are about equally divided between the Ilanford and Pamona series. Here both are excellent for the pro- duction of citrus. Considerable areas of heavy residual soils, at present dry-farmed, and in part susceptible to irrilewood Fault and the AYest Coast. This last named soil is very fertile, and because it is highly I'etentive of moisture is suitable for dry farmincntly slopinj^- portions of hills snrronndinji' the Coastal Plain. These soils are generally fertile and moisture retentive. Because of tillaj^e and irri«»ation difficulties, they are most useful for drv farmins". Between IMava del Rev and San Pedro Hills a deposit of Oakley fine sand of the wind laid province extends iidand from two to five miles from the ocean. The surface is uiuUdating'. makinji' irri*zation difficnlt, and this, together with relatively low fertility of the soil, results in its use primarily for pro,000 12,000 Alfalfa 7,000 7,000 Irrigated grass 1,000 1,000 Domestic and industrial :^1,000 89,000 Total 85,000 93,000 San Gabriel Valley Garden and field 10,000 9,000 Avocado and citrus 81,000 .'U.OOO Deciduous 19,000 13,000 Alfalfa 2,000 3,000 Irrigated grass 2,000 2,000 Domestic and industrial 33,000 41,000 Total 97,000 99,000 Upper Santa Ana Valley Garden and field 26,000 27,0a0 Avocado and citrus 80,000 82,000 Deciduous 27,000 25,000 Alfalfa 12,000 12,000 Irrigated grass 8,000 10,000 Domestic and industrial 33,000 37,000 Total 186,000 193.000 Coastal Plain (iardenand field 99,0(M) 100.000 Avocado and citrus 88,000 93,000 Deciduous 14,000 8,000 Alfalfa 12,000 ]:',.000 Irrigated grass 6,000 7,000 Domestic and industrial 179,000 200,000 Total 398,000 421,000 ■' Incluili-s culiiiiL' on mountains and liills iidjacent to valli-y, but excliKles more distant recreational devel- opment . STREAM SYSTEMS As has been stated, all that portion of South Coastal Basin which lies north of the intermediate ran^je is drained by the Los Angeles, San Gabriel and Santa Ana River stream systems. A part of the Coastal Plain is tributary to these streams, and a part drains directly to the ocean. The areas triutary to each are shown in Table 3, * Bulletin No. 4.'], South Coastal Basin Investigation, "Value and Cost of ^Vater for Irrigation," 1933. Plate A. 30 DIVISION OF WATER RESOURCES TABLE 3, AREAS OF SOUTH COASTAL BASIN DRAINED BY STREAM SYSTEMS (Square Miles) Los Angeles 8an (Juhriel Santa Ana River River River Small streams trihutary to the ocean Total Above the ijit('rnu'. San Timoteo 2()a. North Area 2()b. South Area 27. Riverside 28. Arlington 2J). Teniescal :m). Spadra 40.« Lower Cajon 41.» Tapper Cajon 42." Hear Valley V.\.^ Rig Meadows 44.» Seven Oaks 4r».» Reche Canyon 4().'' Cajalco 47.' Lee Lake 4S.« Cold ^Vater 4^." Bedford Coastal Plain Upper Santa Ana Valley 16. 17. 18. 19. 20. 21. 22. 28^ 24. 2.'.. Chino Claremont Heights Live Oak Pomona Cncamonga Rialto-Colton 21a. Rialto 21b. Colton Bunker Hill Lytle Devil Canyon Yucaipa-Beaumont 25a. Yucaipa 25b. Beaumont :n , 82. 88.^ West Coastal Plain 81a. Northern Area 31b. Southern Area Hollywood Central and East Coastal Plain 88a. Los Angeles Area 83b. Montebello Area Santa Ana Area Irvine Area Central Coastal Plain Pressure Area East Coastal Plain 88c. 88d. 88e. 88f. I'ressure Area 84. 85. .8(>. 87. .50.' La Ha bra Yorba Linda Los Angeles Narrows Santa Ana Narrows Santiago * Listed as "Miscellaneous" in Bulletin 45. ^ For convenience of study and discussion, areas designated in Bulletin 45 are further subdivided. Los Angeles and Montebello Areas serve as forebays for Central Costal Plain Pressure Area, and Santa Ana Area as a forebay for East Coastal Plain Pressure Area. In effect, each group constitutes a single basin. To a lesser degree, Irvine Area Is also a forebay for East Coastal Plain Pressure Area, but it is treated later herein as a separate basin. * Bulletin No. 45, South Coastal Basin Investigation, "Gfeologv and Ground Water Storage Capacity of Valley Fill," 1934. 36 DIVISION OF WATER RESOURCES Characteristics of fill material within the basins varv widelv, both areally and throun o t : • I 1 1 1 1 1 1 T 1 1 1 1 1 1 i/i 1 1 ! : 1 :-T I T J 1 1 I I 1 1 I I 1 1 1 1 1 I'll I 1 ; 1 ■: ! 1 1 III! I 1 1 1 v^ BEAR VALLEY GROUP J \ 1 1 ; ^ v> /- v K r^ K / \y V \ * r ^^i/T"^ \ , ! 1 1 1 T SAN BERNARDINO GROUP , V' vvn^JWI ^ r\. A /va7^ N A /-M V r ' z < UJ 2 5 O > UJ Q ► 300 h200 + 100 /^ RIVERSIDE GROUP ./ /" 1 \ i 1 1 A^ V \ / ■^ / kiA /vl^l/ \ V ^ 1 1 1 -100 D 2 D O 400 300 200 100 1 > v^ 1 1 COASTAL PLAIN GROUP v \ /^ ■\ y ^ f^ /v r^ \ ^V / V V A —^•v f A^ \^ 1 i 1 1 I . : : MM MM MM \ 1 \/Vi 1 1 CUMULATIVE DEVIATION FROM 53 YEAR MEAN PRECIPITATION MEAN PERIOD-. JULY 1.1883 TO JUNE 30. 1936 •to YEAR PLATE 2 _ «o ^ « ^ a> o o o ■n o •f) o >n o vO h- i>- o> o o co o 0> +300 ♦200 + 100 Z -100 < -200 J J t- z u 400 i ' ' 1 ~1 r^ SAN GABRIEL GROUP 1 1 ^ ' 1 i \ 1 i 1 1 / \ \/^ \ K^ rW X] ! q: UJ Q. z o u UJ q: 300 200 100 z < ^ +300 rA^ RAYMOND BASIN GROUP • 1 J^ /\. y .t./^^ Mountain Group .•■■•■■/ ! i 1 1 v^ / Valley Groi jp-A ^\ IT 1 ' ' ■%- r i ! 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O-P o ©^ O BrHQ O C2 Pli- b B «J O (>> © o e -p -p »H -P 03 E 0> 0) ol © 3 S -H PrH C > 10 © O 01 tH hO BO T3 B © O © < tJO-d © ■P B ai *J •H © © 03 a] B O p, 01 -p P h3 c a, to >i Xlt e e c 0) •p B o S © t<= = = c P •* 03 g 01 © Cd S 3 resents a part of the area of South Coastal Basin as delimited on Plate 1. On these graphs the 53-year period, 1883-84 to 1935-36, inclusive, is assigned the mean index 100. During the period of longest record l)rior to 1883-84 the average index was less than 100; from 1884-85 to 1892-93 it was greater; from 1893-94 to 1903-04 it was again less; from 1904-05 to 1915-16 it was again greater; from 1916-17 to 1935-36 it was again less; and since 1936-37 it has again been greater than 100. While the variation is not cyclic in a mathematical sense, in that the two pairs of wet and dry periods are not identical, each pair for want of a more descriptive word is termed a cycle. While the mean for the entire record is not far different from that for the two complete cycles, 1883-84 to 1935-36, it is more logical to consider the latter a period which is rep- resentative of long-time mean conditions, and to assign to it the index 100, because neither the falling period which preceded it, nor the rising period which followed is known to be complete. As previously stated, not all percolation to the ground water is directly from rainfall. A considerable part is from surface stream-flow. To evaluate total long-time mean supply, an estimate of long-time mean discharge at points where the stream enters and leaves the basin is required. No stream-flow records are available prior to 1894, and while it is true that a relationship between precipitation and runoff exists, it is not sufficiently definite to provide the basis for a reliable estimate of the 53-year mean flow, even at the few stations of longest runoff record. For this reason, shorter periods in which some stream-flow records are available are used as a basis for estimating long-time mean supply from that source. Average annual runoff, during any period which constitutes a com- plete or nearly complete precipitation cycle, and during which average annual precipitation is not far from its long-time mean, should not be far different from long-time mean annual runoff. One such period, 32 years in length, starts with 1904-05 and ends with 1935-36. Because of SOUTH COASTAL BASIN INVESTIGATION 43 tlie fact that percolation to the ground water along San Gabriel River was considerably altered in 1938-34, through operation of reservoirs and increased diversions and spreading, the mean annual precipitation on the area tributary to that stream and to Los Angeles River was about the same during the 29-year period ending with 1932-33 as in the 32-year year period, the 29-year period might better be used for those two stream systems. The 21-year period, 1922-23 to 1942-43, inclusive, while possibly not a complete cycle may also be used. In Table 4 is shown the percentage by which average annual precipitation in each of these periods varies from the 53-vear mean. TABLE 4. AVERAGE ANNUUAL VARIATION FROM 5 3 -YEAR MEAN PRECIPITATION 32-i/ear period 29-i/enr period 21-year period lOOJf-O'', to 19()Jr05 to 1922-23 to Precipitutiou Htation group 1935-.U), inch 1932-33, inch I9.'f2-Jf3, incl. (Percent) (Percent) (l*ercent) San Fernando ^__ +4.1 +4.4 +7.6 San Gabriel — .H.O — 3.0 —3.0 Raymond Basin : Valley _ _, +1.3 +3.4 Mountains +1.3 +0.4 Chino — 2.G —1.') —3.0 Bear Valley — 0.6 __ — 8.8 San Bernardino +4.2 +5.1 Riverside +3.0 __ +8.2 Coastal Plain — 3.0 — 3.1 +1.2 As indicated on Plates 3, 4, 5 and 6, records of discharge at one point on each of a few streams extend throughout the 32-year or 29-year cycles. By comparison with these records, estimates of liow during the c3'cle at other points on these streams, and in other streams where records are available during a part of the cycle, can be made. While the relation- ship between discharges of streams in the same general vicinity is better than that between precipitation and runoif, these estimates are also sub- ject to error. In estimates of discharge at points far downstream, based on records at points higher up, errors may be large. Reference to Plates 3, 4, 5 and 6 shows that during the 21-year period points at which the dis- charge must be estimated are greatly reduced in number, and at some points where estimates are required a record is available for the greater part of the period. Locations of stream gaging stations are shown on Plate 7. Results obtained by using one period or the other may in some cases differ materially. The weight to be given to each depends upon the circum- stances, and is of necessity a matter of judgment. In Table 4 it is shown that precipitation over the greater part of the area during the 21-year period averaged higher than that during either the cycle starting with 1904-05, or during the 53-year mean period. On the other hand, values presented later in the bulletin show that average annual stream-flow is less in the later c>cle. Generally speaking, values of overdraft or excess resulting from use of the 21 -year period are the more conservative, and except w^here noted, the values presented in Table 5 in Chapter IV are based on that period. Values based on the 29- or 32-year cycles are, how- ever, stated in Chapter VI for purposes of comparison. PLATE 4 ^ai«l-JR 1 1 1 I 1940-41" 1935-36" ' ; 1930-3t~ ( ■ " ■ 1 i I 1 ■ 1 1925- 26^! ' i ; ; 1 1 , ^^ri ^r i ■ 1 1 ' f ] '■ 1 1920- 2t 1' " 1 ! ' h 1 r~ j . 1915- 16" i i ' ' ' ' ' ' 1 1 1 ' 1 ' M 1 1 ! 1 '■ 1 ! 1910- lO 1 ; : ; : : ! 1 1 1 1 1 [ 1 I 1 1 1 1 " "1 1 1 1905-06 1 1 1 i 11 ! : i 1 i ; ; : : 1900-01 ~^ 1 ; : : 1 ! 1 ! 1 11 1 1 ! 1 ' 1895-96~r ! i ' .11 1 ■ 1 1 : 1 i STATION MAP MEA3. YEARS OP NUMBER INDEX STREAM SYSTEM RECORDINO STATION BY RECORD B.Pk.San Oabrlel Camp Bonlta, above Cattla A-B 1927-32 Canyon E.Pk.San Oabrial Below Cattle Canyon B 1929-34 B.Pk.San Oabrlel 2i miles above Pork B 1938-46 B.Pk.San Oabrlel 2 miles above Pork B 1933-38 San Oabrlel At Edison Intake B 1927-36 San Oabrlel Near Azusa B 1937-46 San Oabrial Hear Acuaa A 1896-1937 San Oabrlel At Foothill Blvd. B 1932-46 San Oabrlel At Elliott Avenua B-B 1923-27 & 1938-41 San Oabrlel At Beverly Blvd. B 1936-46 San Oabrial At Whlttler Blvd. A-B 1928-36 San Oabrlel At Spring Street B 1929-46 1 Below Dam 0e B 1934-46 1 Above North Pork B 1929-34 1 At Camp Rlnoon A-B 1930-46 1 1/2 mile above Bast Pork B 1927-30 1 ml. above W.Fk.San Oab. B 1934-37 Near Camp Rlnoon A-B 1929-34 600' above W.Fk.San Oab. B 1936-37 1 Near Mouth A-B 1929-37 Near Azusa A-B 1917-46 Near Duarte A-B 1917-46 Near Mouth B 1928-46 300' below Monrovia Cr. A 1916-26 tc 1937-46 1060' below Monrovia Cr. A 1926-37 Near San Dlmas A 1917-46 Near Olendora A 1920-46 Near Mouth of Canyon B 1938-46 Near Mouth of Canyon B 1929-38 Near Mouth of Canyon B 1928-46 Below Dam B 1928-46 At Covlna Boulevard B-E 1923-27 & 1929-46 At Workman Hill Road B 1929-46 At P.E. Ry. 4c Anaheim St. B 1929-46 At Pullerton C 1930-34 Near Maiden Avenue C 1934-39 & 1940-46 Or, At Cypress Avenue C 1930-34 At Raymond Avenua C 1934-46 > a < ■i b ( 1 o s. 1 a a 5 OC i a a 103 . 6.6 > a a a *a .H . b b ■> O D I a a J ) o o a a : c c 1 1 a a (. 1 0101 .6.6. : 1 > 1 H H % ^ a B 1 ) S D-16 Bear Creek D-17 N.Pk.San Oabrle P-16 Rogers Creek F-15 Fish Creek E-14 Monrovlo Creek E-14 Sawpit Creek B-14 Sawpit Creek P-18 San Dlmas Creek P-17 Big Dalton Can. V-1'7 T.4I-.1A n. -I •-...- Little Dalton Live Oak Creek Puddings tone Cr Walnut Crook San Jose Creek Coyote Creek 3rea Creek Brea Creek Jast Pullerton East Pullerton Creek 03 ttKDmt- « ID O ^ 10 10 0) ^ lO CO C^ C^ IC f-t iH r-t f~i t-t r-l rH fH rH i-t f-* i-t i-4 i-t t-i r-l i-t n 1 1 1 1 1 1 1 1 1 1 II 1 1 1 1 1 a aaau hek,a.K m mk aaaaa c « « n«oio a o co lOiaoioio i « OlC^O}^ rH O lO ffi 10 OJO CD ^ ® 10 ^ )C P-17 0-19 0-18 H-14 1-13 M-13 L-16 L-16 L-16 L-16 Jr- ) -a >IC »416 »444 1293 1273 I212A 1212 202 1426 374 363 364 457 S180 013 967 046 171 172 611 192 ft CO Q a. o u 5 u UJ or 1- (0 ^ >- (f) o _i a. u. u > 5 cr < LiJ -I cr u 1- rr U) CD ii < o o (0 z a < o en cc u Q. b •» • TJ a«> C -< o a Q-i b ■ • i-i -p a W c a o • *-S b > ■« O 3 b c o 3 C rH B CO o o • a b -» (C rH 13 *S C a o c a b o o o i a ♦arH o -P ■** eo6. b a « a s •i >>o a. 043 o a Vi • CrHQ O Ci 36. O b c « c^ >>a o a 4^ 43 ^ 4^ a c a B a a 3» ri 4>rH C > 01 a o o .H w CO 'O e a • c 4 w« a 4J c a *> •H B a B a c o b a 43 S.JC (k 01 44 PLATE 5 7945 -TWI "" ^ ""■ ~~" — — — — — — — .. — 1 - — - - - — : "~ - _ _ _ "■ — 1940-41" — ^"^ *^~ " - - - - ■ — . - — . . - — 1935-36" — - - -- - - - - - " ~ ■"■ - ■ ™ ■ ■ - — - - - - - - ~ _ - — ~ " 1930-31 ■ ~ r- ■ ■" ■' -* 1 — - - -- - - - - - __ - - u - - l925-26_ - - -- - - - - - h - h - — _ _ _ ~~ — ■-i 1920-21 _ . _ _ . _ r" _ _ " — ■■"" — — "■ " - - - — — ' - -1 J - 1915-161 — ' — — ' ^- - " -- -- - - - - T — - — _ - - -. - - -- -- - - - - - - - - : I 1910-1 1 _ ~ — ^ _ . '■ ■" r 1905-06 ■■ - ■™ ~ mm. ^ ' 1 — — '~~ _ _ 1900-01 ~ ■■" . _ "" "" .... _ ■" ~~ 18^5-96 ^m- ■" toe (C o «* 0> CO gj O O O C O O) 10 iH Ol 01 O) (O-^OJKJWO OOoOfOO ■* CD CD (£> (D CD 05 C» 0> Ci C- O 2 r-< tONWtO (OlO(0^r-HW r-lMtOrH W (O (0 « W OJ W N « « r-t OJ rH rH lO O) K5 tO tO W W « OJ iDo> oioiojo o>a)ato>o:CT oic?ic7>o> a OiOi o> o> a o* a ot (x> <7> a oiO>Oia>Oio>Oi Oi o> c 3iou: 1 1 r- r- acMti to to too to to ■* .H ■>!■■«•■* •* IIIIII to fH fH 0» O 01 rHO lO CMCMCM lOlCJ 4fHf- OI OI 01 01 OI (31 ■H fH fHtHfHiH < 1 c b c (/ I s 8 < c 4 ( < C/ C f c a s < ) ^» i ) 9 « ?5 ^ c 1 4 )5 i f 4 a t < :a d a : t s< 9 c t < 1 c/ •Ir- IV 3 C - a ^C >C no ■t f e <3 V toe •o c •ri ~- ) Xi t- ; a Itl lli i -p to c . 1= tr iW 1 d : E c-< IS i§ )co < CD 1 CM 1 3X 3 lO 3 O 30 ft 00 H fH •* c X (• d C (. o aa c a CO (. ti c d C < 4- c K a 0. 1 X z a < c ? to fH < ; c > 1- c c E a 3: » a c < a 4- c a v cv 0. :<: tr 1^ cc t£ << (D tt •c t- a c a T) C < a ■4- § cr cv cv 1 c^ c cc tC < ) c T .L I z « t 1 f- cv If a IT 1 1 t, o. K o fH e X) o •D d U 0. (. d c s d > -p .§ ) CO < < a s P 4- c c d a yi cr O tc [Mr- 1 1 JC CMtr CMCT B -a lO •« rH ,- 4 c ! a t a J ( c. a '4 K c c t< K a * J- a t. >u ) > t 4 a » J< C '.I >c 1 f- a It cv )|r 1 J e ) f- >tt ) cv ) (X 4 p- > g ! i a u a « CJ c a c E ? E- ) C a m o > ir 1 i H > s > r- t a. 4 m X s H •0 a a s- n « b CJ c c c E E- s to a cv 1 tc g cc < f? •H a c J< c « CJ > u o IT < ■c C « a c ■z < c c >l> 4 c c |r 1 li tr 5 ct < B to ■o d s Ob U < d B z g & a 1 ■.B P d S m CM 1 u o CM g « C c c +■ ."c c !S c ■ •I e ;r > a 3 is < lir ) ) O c- 4 :> c c ( X c c < l a t 1 a 1 cv t_ c < K ! « Ji C C ( X c a • ( ) < 1 s ( c. I a icv if If 1 t f- g •o (. d ) C tf B CD B d to . I. d o z B c o l-l «-» ^> 'S •r- )CM 1 U !o, > to r to > 01 t r^ 19416 D-24 Lytle Creek Near San Bernardino A 19449 E-25 Lytle Creek Near Pontana (Mouth of Canyon) A-P 18703 P-26 Lytle Creek At Junction with CaJon Creek F 18704 F-26 Lytle Creek Fontana Power House F 18746 F-26 Lytle Creek At Highland Avenue P 18767 F-27 Lytle Creek At Baseline Avenue P 16769 G-27 Lytle Creek At Foothill Boulevart* F 17980 G-27 E.Br. Lytle Creek At San Bernardino A 17962 H-27 W.Br. Lytle Creek At Colton A 18561 E-23 Day Creek Near Etiwanda A 4572 E-21 Cucamonga Creek Near Uplands A-E 15985 M-23 Temescal Creek Near Corona A-E 15991 L-23 Arlington Drain 0.4 Mile E. of HcKlnlay C 5638 E-20 San Antonio Cr. Near Claremont A 5688 E-20 San Antonio Cr. Near Uplands A 4614 P-20 San Antonio Cr. Mouth of Canyon B 15850 L-21 Chlno Creek Near Prado A-E 15728 N-18 Santiago Creek Near Villa Park A 14513 0-16 Santiago Creek At Santa Ana A - O (/) _l u. CC u 5 > < cc UJ cr < H z (r\ < o s in I 9 ^ cc u Q. o Ort o ■o k ■a B d .fH -P o >>C B O B t4 *H U >-PQ 3 t, B O • 9 CfH B »% CO C3 O • B □ UVK 3 rt TJ-P B D. d O B S t. S O O C fi 6 O » *> 430 bOCi. U d c « ds t. fH »^ o P< B O -P O B tH 41 B B «H Q o d O 3(i. S O h B B C3 K» B O C B 41 P .-t C 41 n B d n ^ d e 3 s 'H B 41rH O > 3 to B O d *-l tc BQ d Q B B B B B < t^O'O B d 41 B d 41 4> ^ a d B d B B O (• d P O O J OO. t0 6. XJe = e = = 5 B (.C E 3 a 401 OPM b 45 PLATE 6 1945 -46^ 1940 -41-^ 4< :vl ^J- CM to ■«}' ^ eO to (M to OJ rt CM to Ol to to to to to 'J' to « 'I* to 'J' C-^Cir-l C-O OOa>rH 00t>0C~-0o0t-0 <-liHrHi-H.-lO Cn0 < a CMtOtO'* CMtO CMtOtO-=:< tOtOCMtOCMtOCMtOCMtO IOtOtOlO'J)01 O^CTj OCJiOlO 0>0^0>OiOiO^OiOiOi a Oi Oi C> Ci Oi OiO>C7iO> Jh r-lfHrHi-H l-Hr-l fHr-lr-IiH i-Hi-lr-lr-lf-lf-lr-lr-lrH rHrHi— IrHl-li-l iHr-liHi-l • CO « Mca wwww 3)cQ <;>< 1 1 1 cjoiiii oooocj Doaii • go cj oo oooo <<; a z c n a o o £) © » 3 • 13 3 f, S. f. ^. r^ -P © S C O O « > > > -P 3 • ■H CU M > .rt »^ »^ -H © ^.^ C T) h E^ •d ■n • -o << « 3S,4Je-l >rliH(>% n -p C E^ O Uei'OiiiTlai'aaSxi C-uCo <<>cQa ■HO d to K oCoJCOtCoJCa! a>c03 i-lt « -H 13 N«;o«:o<:coc c ca a s: %, o o •a -p d -pKKcce > O ra o n O O K «)i:n4Jm.peo-i->oj -Ptfjl -a SOr-l © 3: > -PQ 5 a « P. BCEcacecE tnoicjMC Cr-ic $ SI cocgcaaoaiasa ©ka)r-i.H •t-io.h© K t, c c c O O E CO "O CO "O CO T) CO 13 a 73 V -rl rH C 4J *i 4J C » a ■Pi;-,<:<;< 3 O rH n O CO o c • © « p. -p b: cc ►J t, <: iH o-po-uo-uc+j E- 4J ^O**** 4->OCi-IO 4J4J4-34J o c c E © <4 s: «< O CO ^ S S S «<»i-JCQ s > c a • • e C *:> C © Vh • si si a s. MHO c © C rH Q c O 3 [i. a d to JO *J43*>-i-> c/jCioo d^^o C h C w C d d •.MT^T^•H *J4J^ j3«o>^ o o (>-> © o £- ■rt C C MMQ O O Q bOW-H»< « O » O C © JJ p ^ CO U d d QQCCBC 3d t< MOUO ■p o C d n fe d © 3 3 .H Q Pit, ^^»HtH xi^cccjo p iS o«dddd nntiOt« 3dd« ■P rH C > CO o o d »H :« C "H n O OQ a P) Ct »oCC O BCOC 60 C Q < 73 C O « ^ -^ Si E jcjx: *J4Jirt^^wiHrHd © < ta-o © K > f-i 3 SfcxI-O-O-p ccddt, B>-irHO. p C d -p E- ti © 13 ©©-PtiCn -HiHtitd Cddo > X > <0 lO UJlOI'lOIOlO ^■■"ftOtOC^ OtOtOtO CL-M iH r-l rH rH iH rH i-l rH r-l i-H rH iH i-l rH a |g Of or cf a, CL, Of - T LEGEND j-,^ _ ^^ WATEBSHEO BOUNDHOr .^_/^,_,-T-»_ ^^ EOCC or NONWATtR - BEAflINO ABE* l~< - CMOUND WATEd BASIN BOUHOAnV ^■^^(^^ SUB-ADEA BOUNOARV >»—«"■« APPROmUATE BOJNOART OF PPESSUPE lONE 6 CnOUND WATER BAjIN REFERCNCt NUMBER • 2416 9TSEAM CACINO STATION BEAA MtlSY nCS ^^L'"^H3.. '>l 18096-^0,. O \ < ^ rh — Nl 18128^ 26 \ 25a V^..^^^ P/^ 7 ■% V''-'^ ^ RIVEHSIDF \ "CO y^ ^^jf/^ ^:^^--.^ V"^^^^4^ J ^~N GROUND WATER BASINS UPPER UPPER SAN FERNANDO VALLEY SANTA ANA VALLEY SANTA ANA VALLEY AT 1 r CL AREUONT HEICHTS WtaT COASTAL PLAIN - NORTH SAN GABRIEL VALLEY MOLLY WOO L03 ANCELEa SANTA ANA HARROWS A / .LA/te EtSINOfE r^~\ SAN JOkQU'** *^ f<^V^ -/ ^. DEPARTMENT OF PUBLIC WORKS DIVISiON OF WATER RESOURCES SOUTH COASTAL BASIN INVESTIGATION STREAM GAGING STATIONS I " I '- I ~is~r ~^ZL ~sr^ I 2Z I 23 I 24 I gS I 26 -^^~r 34 1 35 I " I CHAPTER IV. EVALUATION OF OVERDRAFT OR EXCESS As illustrated by the well graphs of Plates 8 to 19, inclusive,* the iter table in all basins rises durint>' the rainy winter season when tractions are small, and falls during the summer. In virtually all sins it becomes progressively lower throughout the dry period of a cle, and rises progressively during' the wet period. If average annual t extractions from the ground water during the cycle, and average nual net supply to it are equal, total rise and total fall are equal, and B water table stands at the same elevation at the beginning and end of e cycle. Where average net supply is the smaller, how^ever, the eleva- •n is lower at the end than at the beginning. The fact that the water table in a basin has so dropped in some past cle does not necessarily indicate an overdraft. In some basins outflow, rising water or underflow, responds quickly and in relatively large lount to changes in water table elevation. Where this is true the crease in average outflow during a future cycle, resulting from lower erage elevation during the cycle, may be sufficient to balance excess tractions, without the Avater table falling below the level from which mping is feasible. Where it is apparent that the balance will not be ig delayed, an overdraft is not considered to exist. Since a higher w^ater Die correspondingly increases outflow, it is equally true that in such 3asin there is no excess. In a few basins lack of storage capacity limits p period during which either overdraft or excess can persist. In lymond Basin Area, which includes Monk Hill Basin and Pasadena d Santa Anita Areas, extractions are limited to safe yield by court cree, and in Beaumont Basin the drop in water table elevation is ntrolled by a court limitation on export. In those basins where no legal limitation is in effect, and from which th surface and subsurface outflow are little affected by water table ^vation, or where a considerable period of time must elapse before tflow will change enough to bring about a balance between supply and mand, a decrease in the amount in storage between the beginning and d of the cycle is considered to indicate an overdraft, provided that long ne mean net supply to the ground water under present conditions is I greater than historic mean net supply during the cycle, or present tractions are no less than they averaged during the cycle. If present conditions, both as regards supply and extractions, were entical with those which maintained throughout the cycle, average mual decrease in the amount in storage during the cycle would meas- e the amount of the overdraft. Generallj^ however, present net extrac- )ns are somewhat greater than the average during either of the cycles record used herein. If this is the only change which has occurred, •esent overdraft is greater than average annual change in storage by e difference in net annual extractions. On the other hand, where the ;t supply has been increased through spreading, through greater * Location of wells involved are shown on Plate 20. (47) 48 DIVISION OF WATER RESOURCES importations or by other means, overdraft under present conditions is less by the amount of the increase. In other words, overdraft is the aver- age annual amount by which the quantity in storage would have decreased had present conditions affecting supply and demand main- tained throughout the cycle. Evaluation of overdraft does not require, moreover, that a record of water table fluctuations throughout a complete cycle be available. Any period in which change in storage can be determined provides the basis for an estimate. If average annual net extractions during such a base period were the same as those of the present, and average annual net supply the same as the long-time mean, average annual decrease in the amount in storage during the base period would be the same as that during a complete cycle of supply under present conditions, and would measure the overdraft. Where they are not the same, under the coiuli- tions set forth in the preceding paragraph the difference between present and base period average net extractions increases the calculated over- draft, and the difference between long-time mean and base period average net supply decreases it, each by the amount of the respective difference. For reasons discussed in Chapter V, the 11 -year period, lf)27-28 to 19':}7-38, inclusive, is one in which an acceptable estimate of change in storage is possible. In this period, too, average annual precipitation is generally not far different from the long-time mean, and the modifi- cation required in order to account for differences in items dei)endent upon the weather is therefore relatively small. While overdraft results in, and in nearly all cases is measured by change in storage in the ground water basin, it is actually, because of interconnection between surface and ground water svstems, an over- draft on the entire supply to the overlying area. More water leaves the area by evaporation, transpiration, export, surface outflow and under- flow, than reaches it in the form of precipitation, stream-flow, import and underflow. Because of the fact that direct determination of percola- tion to the ground water and net extractions from it is difficult, the above items are used instead, where such procedure is applicable. In the pres- sure areas of Central and East Coastal Plain, however, where percola- tion to the ground water from the surface is negligible, it is the differ- ence between present and base period average annual exti'actions whicli is significant. Under any procedure, overdraft is the average amount which must come annually from underground storage to make up the difference between supply and demand. Changes in storage during the base period, modifications due to differences between base period average annual and long-time mean annual amounts of water entering and leaving the areas under present conditions, and resulting values of excess or overdraft as derived in Chapter VI, are presented in Table 5. Here the modifier and the over- draft or excess are rounded to two significant figures. In the last nine basins listed as part of the Tpper Santa Ana Val- ley group, in Chapter II, there is either no development, or so little that obviously no overdraft exists. These basins are therefore treated as a part of the area tributary to lower basins, and are not considered separately. The Department of Public Works has been appointed referee in a suit recenth' filed in the Superior Court for Los Angeles Count}', having SOUTH COASTAL BASIN INVESTIGATION 49 as its objective the limitation of extractions from the ground water of AVest Coastal Plain to the safe jield. Over a large part of this area the water table has remained below sea level for many years, and a part of the supply to the ground water has been of a quality unsuitable for general use. Because of this, an evaluation of overdraft involves a far more complex and detailed study than is required elsewhere. In order that publication of results for the remainder of South Coastal Basin may not be delayed until such time as a detailed study is completed, no value of overdraft in West Coastal Plain is here presented. The fact that the water table has long sloped landward from the area of contamina- tion, and that the increase in slope has recently been accelerated by large increase in extractions, shows clearly, however, that the overdraft is large and the situation critical. Present conditions as here defined are those of 1944-45. Reference to Table 10 indicates that increase in consumptive use is generally rela- tively slow. Import and export of water, both of which are subject to arbitrary increase or decrease, may in some cases change materially within a year as may export of sewage. Outflow may be arbitrarily increased through paving of channels or decreased through spreading or other conservation measures. Until sufficient time has passed to pro- vide another period suitable for use as a base, it is believed that the values of overdraft presented in Table 5 can, without introducing material error, be brought up to date at any time by adding the increase in export of water and sewage since 1944-45, and subtracting the increase in import and the net salvage where it is significant. 50 DIVISION OF WATER RESOURCES TABLE 5. ESTIMATED ANNUAL OVERDRAFT OR EXCESS BY BASINS UNDER PRESENT CONDITIONS (Acre-feet) Average unnunl change in storage during base Basin name and numher period '^ Venlufro Basin (5) +690 San F«'rnan(l<> A'alley Area * (1, 2, 3, 4, :5,s and .'{Ih +9,370 Kayimnul liasin Area Western Unit '«= (7 and 8a) — 5,810 Eastern I'nit' (81)) (llendora liasin (11) +2r)0 Way Hill liasin ( 12 > +220 Foothill Basin ^ (14i San Dimas Basin (1:5) +110 Spadra liasin (30") —840 Puente P.asin ( lo ) — 340 Central San (lahriel A^alley Area ''^ (6, 9 and 10) ^4,360 I.a IIal)ra Basin" (34) 7r>0 Lower Los An^'eles and San (Jahriel Kivers Area ^- (32. 3:ia. 33b. .33e. and 3(5) — 12,JX)0 Clareniont Ileijihts T'.asin (17) +270 Live Oak Basin (18) +10 BonK.na P,:isin (19) — 2.7()0 Cncanion-a Basin (20) UK) Hialto P.asin (21a) —340 Lower (\ijon Basin ' (40) Lytle Basin ' (23) +3,4G0 Devil Canyon Basin ' (24) +1,280 Vucaii)a P.asin ( 2r)a ) — 2.350 Beaumont Basin ^ (25h) — 740 San Tinu.teo Basin ^ (2()) +230 P.unker Hill Basin ^ (22) —520 Coltnn-Keclu' Canvon Area'*-' (211) and 45) —130 Kiverside-Arlinj^ton Area "^ (27 and 28) —3.7(^0 Temesoal Basin ' (29) — ___ +270 Chino Basin ( 1() ) —22.810 Irvine P.asin ( ;i3d ) — 3.120 Lower Santa Ana River Area *" 33o. 33f. 35. .37 and 50) — 14,()9() Modifier ^ Overdraft Excess —930 + 16,000 + 310 + 490 + 700 + 10 + 1,400 + 220 + 900 —1,700 + 200 + 560 + 6 Averai-'c of l'II- and J 1 -year mean annual values used. ' Subsurface outflow calculated. J Thirty-two year i)eriod considered cycle of long-time mean supply. SOUTH COASTAL BASIN INVESTIGATION 51 COMBINED OVERDRAFT OR EXCESS The interrelationship between basins, while especially marked in the case of the g:roups presented as a unit in Table 5, is common to other oTOups as w^ell. Lowering of the water table resultant from a long con- tinued overdraft on any basin influences the interchange of water by export and import, and in some degree affects outflow from an upper basin to one downstream, thus decreasing overdraft on one basin and correspondingly increasing that on another. For this reason, overdraft on the group is often more significant than that on each of the basins con- sidered individually. The same is true where the rise resulting from an excess is more rapid in one basin than another, or where an excess and an overdraft exist in interrelated basins. Los Angeles River Ground Water System Above Los Angeles Narrows, only Verdugo Basin lias been treated separately. Export from that basin to San Fernando Valley contributes to the overdraft in Verdugo Basin and to the excess in the valley. AVhile extractions for export are so located that their effect will probably be long delayed, continued overdraft must eventually result in reduced export, with a corresponding reduction in overdraft in Verdugo Basin and excess in San Fernando Valley. The combined annual excess above the Narrows is about 25,000 acre-feet. As brought out in detailed discussion in Chapter VT, this excess includes a large supply available in Owens Valley and Mono Basin, and is potential rather than actual insofar as its effect on the rising water at the Narrows is concerned. Furthermore, even if the outflow of rising water were increased through importing and spreading water not now required for use, the increase in percolation to the ground water of the Coastal Plain would be negligible, and since direct diversion to use of the rising water is infeasible under present conditions, there is no point in deriving a combined excess in San Fernando Valley and Coastal Plain Basins. San Gabriel River Ground Water System In this svstem Central San Gabriel Vallev Area and La Ilabra Basin, both as regards surface and subsurface flow, are tributary to Lower Los Angeles and San Gabriel Rivers Area. Western and Eastern T^nits of Raymond Basin Area, and Glendora, AVay Tfill, San Dimas and Puente Basins are tributary to Central San Gabriel Valley Area. Foothill Basin is tributary to San Dimas Basin, and Spadra Basin* to Puente Basin. In Spadra* and La Ilabra Basins, wliich are overdrawn, the water table will fall if present conditions of supply and demand continue, until the resulting decrease in ►subsurface outflow balances the present overdraft in those basins. This will decrease the snpply to Lower Los Angeles and San Gabriel Rivers Area directly in one case, and to Puente Basin. Central San Gabriel Valley Area and the lower area successively in tlie other. In Glendora, AVay Hill, San Dimas and Puente Basins, on the other hand, an excess is available, and so long as present supply and demand conditions continue, a progressive rise in the water table, and ail inci-ease in avei-aiic annnal outflow to Central San Gabriel Valley, and » Geologically part of Upper Santa .\na Valley Gnuip. as listed in Chaptt r II. 52 DIVISION OF WATER RESOURCES thence to Lower Los An^reles and San Gabriel Rivers Area will occur. The net result, if present demands continue until all tributary basins are at equilibrium, will be an increase of about 2,300 acre-feet in annual flow at 'Whittier Narrows, and a decrease of about 1.800 acre-feet in the over- draft below the Narrows. This would require, however, that demand remain as it is for a lonjr time in the future. It is more probable that a part of the excess above Whittier Narrows will be accounted for by increased demand in the tributary basins, and only a part will benefit the Coastal Plain. The values presented in Table 5 represent the amount by which demand must decrease or increase in overdrawn or oversupplied basins, respectively, if water table elevations are to remain substantially as at present. If, on the other hand, demand is unchaufred. and the water table is permitted to fall or rise without limit, neither excess nor overdraft exists in the tributary basins after equilibrium is reached, and the annual overdraft on Lower Los Anofeles and San Oabriel Rivers Area is about 10,000 acre-feet, or about 2,000 acre-feet less than the value for that area considered independently as shown in Table 5. Chino Basin Group While outflow from Chino Basin contributes to the flow of Santa Ana River, no evidence has been found that the amount of this flow is influenced by elevation of the water table. This indicates that lowering the water table enou^rh to produce significant decrease in outflow, as subsurface or risin^r water, would preclude continued extraction from manv wells, and thus automaticallv decrease the demand on the ground water, and henee the overdraft. For this reason, Chino Basin and those tributary to it are frrouped separately from the remainder of the Santa Ana River ground water system. Pomona. Claremont Ileijzhts, Cucamonga and Rialto Basins are directlv tributarv to Chino Basin, while Live Oak Basin is tributary to Pomona Basin. Subsurface flow between Chino and Spadra Basins miorht be either increased or decreased with long continuance of overdrafts in the two basins. Claremont Heights, Pomona, and Chino Basins are all overdrawn, while Live Oak, Cucamonga and Rialto Basins show a small excess. The tributary basins are interconnected with Chino Basin, not only through underflow, as discussed in connection with the San Gabriel River Group, but perhaps more significantly through export and import by entities producing water from both basins. Combined annual overdraft in the group is about 21,000 acre-feet. Santa Ana River Ground Water System In the portion of this system not discussed in the preceding para- graphs, Irvine and Chino Basins are tributary to Lower Santa Ana River Area, Temescal Basin and Riverside- Arlington Area to Chino Basin, Colton-Reche Canyon Area to Riverside-Arlington Area, Bunker Hill Basin to Colton-Reche Canyon Area, Lytic. Lower Cajon, Devil Canyon and San Timoteo Basins to Bunker Hill Basin, and Yucaipa and Beau- mont Basins are tributary to San Timoteo Basin. Of all of these, only Yucaipa and Irvine Basins and Lower Santa Ana River Area are con- sidered to be overdrawn. In etfect, all others, except Beaumont Basin where a le^al limitation on ex]iort from South Coa.stal Basin is considered SOUTH COASTAL BASIN INVESTIGATION 53 to preclude either overdraft or excess, are already combined in the evalu- ation of overdraft in Lower Santa Ana River Area. If present extractions from the overdrawn tributary basins should continue until the overdraft in each is balanced by decrease in subsurface outflow, as discussed in connection with San Gabriel River ground water system, annual overdraft on the Lower Santa Ana River Area would be about 4,000 acre-feet greater than the value shown in Table 5, or about 14,000 acre-feet. PLATE 8 Year 160 159 158 157 1560 E 1250 ■^ 1240 m 1230 "D 1220 -S^.,^ -- __! ; A-SId . SURFACr EL 1692 ..y^ \ ^ / 1 i 1 1 "T-r-IN ^ i / 1 n 1 ' 1 ^^^ i ! ■ ' 1 I ' T ' f\ A. A/''--< 1 ' A-48 SURfACE EL 1285' s ,.-'''°"-ar\ A, /"^ -W^ ->- j'^wf V ' 1 -nV in O CO 0) (0 I- -♦-> to o c o > I 130 I 120 1110 noo 940 930 920 910 900 890 \ ! Flowint it ' i."°"r«^- A- 24a SURFACE EL 1120 K r^ j-^-^-r-' ■o- V, '/Nat ^.tATV^ ^ r r ^y/^ 1 1 ■^.o MA'1 1 i A- 98 . SURFACE EL 964 1 J 1 0^ 1 i y . • —-J — ■ — 1 — ^^ /I ■J 470 460 450 440 430 1 c 3. V), Oi 2: 1 < 3l J: : 1 K 1 i ILL „ ' 1 1 1 1 ' 1 o '■ ' N . 1 /\ !\\\i \ [YArx,^ ij^^'^'AAiV t A-93-0 SURFACE EL 4«8' V i \J " ] ■ \l ly ^ V V- 1 1 ^^ 1 , 1 1 . 1 i , , FLUCTUATION OF WATER TABLE AT WELLS SAN FERNANDO VALLEY AREA £c VERDUGO BASIN 54 PLATE 9 Year FLUCTUATION OF WATER TABLE AT WELLS RAYMOND BASIN AREA 55 FLUCTUATION OF WATER TABLE AT WELLS EASTERN SAN GABRIEL VALLEY AREA J 56 PLATE II Year 530 520 51 5 00 490 480 e Z3 (0 ■D d =3 320 3 10 300 2 90 280 2 70 260 C 250 0) 0) (D -I-' c o > 300 290 260 270 260 250 oooooo o So — — — -•-••-- — — — --fvitvi<\i<\iw(\i(\iN C-337 SURFACE EL. 6S7' /■ V, I /' •* / \ 400 > r / 390 \ ^ \ 1 / \ S, -~^ / 370 "^ /I A /\ \ C-335 SURFACE EL. 538' ■v. ..*. k \ A 330 '^, V l^ \ \ \ \ 320 ',* .^ r \ w 3 10 "I 1 \( V \ 1 300 l \ \ A h A \ ^ \ A A i li/\ 11 '\ ' /^ "N r>- ^ r- _ ■^ ^ V \ \\m V ^ -\ r^ -^ . 270 r /'• 'v ' TV. -- ■\- r V \ ^ V Ml/ r ■N ^ r 250 24 C-231 V. /v \ ">, fs '\ A 'V/ C-23IP < >URF ACE EL 28 2' "v. > f SURFACE EL 286' aOO »80 440 400 350 300 330 ' ^ ^ ^h A A f\ ^A '\ 1 < /, |\ /\f\ \ ^ \ C-294. -*t-C-294a SURFACE EL 382' | SURFACE EL 387 A \\\ A \ ^ \ 1 1 1 K < \ A \ s \ \ [\ r M \ A \ \ \ 1 1 I ^ '\ ^ »» ■»c 1 \ \ A r y 1 h M \ / / ^°° f- ■s. v. l\ ' \ \ n A A A \ <>«. ^ f^ ^ /^ -- '" ^ S C-212 ' \J "V 'N '^^ ^ \ ' A fi ^ ^ r> s URF ACE EL 2( >3' 1 1 '\ >■>>. M ..r- ^— — r 1 1 250 240 320 300 •o>< O' 'O' 'o' tVir ,tni ,^, o», o>, at, k k 330 320 310 300 290 280 270 1 —1 ^^ .o A \ ,, — -- "^ \ C-282 SURFACE EL. 465' k \ s \ |1 \ ., - -- ■' \ i ' <\ ' \ \ o- — ' \ \ \ ™\ A T \ \ K \ A . r J r^ \ A K A ^ \ M ' \ ' "Ta I ;»; 1^ i i -^m C-206 ^«- SURFACE EL 535' V V ^ 'V\.-ls^ 1 "^ 250 330 300 26 290 250 3 1 V r^\ 3 00 VI "v \ . k 1 p \ f N ^ 2 90 — ^ -^/^ V ., f ** J 2 80 C-241 SURFACE EL. 416' ^/vA- \. r 270 — V . Z5 ^_ J rj 2 60 — _ 1 i S' ^-v' l320 'ml ,o, 320 310 300 2 90 280 270 ■•' I — t lull 'm' |iO| + A-J^v J .\h"^y^A >■>. 1 Jv^rv'^-v "-,'^'^' ^ ^-v ^' r V, 4-lln n5^ _l C-317 — ♦— >: ^ S^^^" SURFACE EL 330' T!^^> :x^^^T ZL ±.~^ it n r 1 300 260 32 300 270 FLUCTUATION OF WATER TABLE AT WELLS SAN GABRIEL and PUENTE BASINS 57 E D -•J CD ■D c/i -t-> 0) 0) £1 (T3 (0 o c o -t-> (0 > (1) Year - c\a to ■* "O O O O O O 0) 0) (D r^ e o> o o o o o 0> — (\J tn -v to t^ ID Ot o 9 ~ oi n -^ (\J OJ M (\| 0) cvj M Pa (\j o 0) _ (\J (0 •* a 300 290 280 270 — oj « o o o n (O CO O) w C-968 , SURFACE EL 350^>1 "„ :i?E ..«^-'L <0 t^ . -<■« 7^^>^^^^^300 1 60 1 C-808 SURFACE EL 191' 1 C-819^-C-819Z ^ /SURFACE EL. ISO' f^^^ «w \ 1 "KCt C-822U ; i ^ \k hr ■h. f. -X 1 fs fv>v '^ ^ -H - C) ' r rp^ rv C-822bb -A n^^ < ''- A/ K^^ A ^ ^> *\\ r^ ^ ^'-j ■•/-I 1 ) /Vo'N SURFACE EL 147' ^A C ^JQ^ ^ }\ '\ c-eo8 /\ / / ' ~T5 0-848--' SURFACE EL. ( t )' A/ V\ -K \ M ^^'^J:^ >'\/ TV ^,C-825^^ >. lAl T-J Kfv o i \j • IV \] L f /^ ^vn t * \> \/ Va / \ k^ K / C-877d SURFACE EL. 70' \ , \ .^^ \ \J AT n i> \] V tl ^n (\JV \/\/l/ \ \/ \ V V •surface el well C-825tg=135' V V V V |V I 1 (60 150 140 130 100 90 80 50 30 O O Ol I lOI |0, r — I liOl i2i i>r)i )- .... -■' •- ^ ^ - -- •- -•J - -T -• •- -^ - -4 3 \ c- 814 r^ rv r\. -\ c \ A SURFACE EL. 176' A \ ^ 1 ) - V «^ _ \ 1 a \ A ^^ ' V ' — n C-827 SURFACE EL. 140' ' ~ ~ - - - -J ■- -ai fco ■o*, \ \, A a \' /> -\ ^ ■% T v7 1 fv \ r ^ N n \ \ V \ (T^. /s / ..C-872J Surface el 98'^ \ n!/n < - , ^^ _ , ^n ■ 1 ■^'N -^ rs r' "' ■ •" - ■ " ". _ ^^ r \ M li \l t^ \ A \ , \ . M \j \l k C-861 SURFACE EL. 84 \ v y\ X [Yyxj V \l w ^^ c^ 1/ \i V V \i\ i'\ i\ 1 mi\( A V y v V i t 1/ vu V _ j 1 1 1 " o O) 290 280 160 150 140 130 f 2 ■;. I 1 100 90 80 70 60 50 40 30 lec 150 140 130 120 1 1 100 PC 80 7 6 50 4C 30 FLUCTUATION OF WATER TABLE AT WELLS CENTRAL COASTAL PLAIN - EAST HALF 59 PLATE 14 E -»» (0 ■o to CO -t-> n 0) ■4-> (0 c o ■t-" (a > (U 1500 14 50 1400 1350 1300 1250 1200 1150 1 I 00 1050 930 900 Yea r o 0) o ID O r^ lo o» o o o o 0> "~ CM fO -* "0 01 (0 r«. oo o> o iCM Si w at ID f- to O) (\liC\l (Si O m f) f) m ■0 at ID m mm o 0> — 1— — t— — i — a> .c^ — •4 -:C «' -^ -s, r \. D-1188a SURFACE EL 1454 / \ 'S r\ri^:n -^ o'^S "^ Y>\ J^ \ i\ j / ^i N rv A D-1l06g SURFACE EL 1488' \\ v^ aa i r' \ V \ '^ r^ A '-fs J f^ n \ '\ \ ^\ N A Ai r o — o- o- o-o. -k- •», h V V ^ ^\/ V «-= \'^ " SURFACE CL 1406 o „ i^x^-. ■»J-^ ^ V 17 D-1072b — ■z. D^ -107^-n i i ^1 ! _ 850 800 790 780 7 70 760 750 740 730 720 7 10 700 650 600 1500 1450 1400 1350 1300 1250 1200 1150 JlOO 1050 550 " ' ! D -1025 n s ^ ^ SURFACE EL. 1330' 1 1 ; ; X ^ H >^ N. X D-1081 s V,. _ ^ SURFACE EL. 1106' 1 K > 1 ^ 1 1 1 —.J ^ __ -""^ i i ■«v D-1050 SURFACE EL. 11 65'° 1 ~- ' "^io— ' \ rvj \ _ "V i ^ -* 0. -.. ., rXfvj -V , D-t044 SURFACE EL.9J •at O-c ^, 0- 0- — ' -v ■~ * *^ -0 , ^- P, /\^ k A ^l ^ 7 \j ^ '^^ V n ^ \ \y v\l\ -V ^ 1 D-772 SURFACE EL. 570' ■ ,•«■ ^0 "■ "" V V 1 — "" ~ ■ r" '■■ V V '\j ■\/'> /\iV 1 ■ ■ ; ( o o 0) id' r~ a> o o o O) o o 5 - (M m ■^ ■0 a « r- CO 0> W N (M m (VJ 2 W (\J 00 0) (M tVJ i t * «0J « rt 1 0> m 00 m O) 0> 5 2 930 920 91 900 890 880 870 860 850 840 83C 820 8 10 800 790 780 770 760 750 740 730 720 71 700 690 680 670 650 650 640 630 620 6 I 600 590 580 570 560 FLUCTUATION OF WATER TABLE AT WELLS LYTLE. CUCAMONGA. RIALTO £. CHINO BASINS 60 PLATE 15 E (0 "D CO o CO d CO (0 o c o > u 2500 2490 248 247 2460 245 2440 243 2420 rear o (VJ (vl (M (VJ ;5 >o 0> (\J (\i CO 0> <\J o n m lO 0) ^ o> E-137 SURFACE EL. 2653' \ D V "•<^ •«> ^> ""\ ^ « riX ^ •O' .-X ^ ^ ^ " y 2500 2450 2420 O 910 900 890 880 870 860 850 1 .<* • - •- - - -< % E -75 1 A rv \ \ i . E -75c SURFACE EL 915 \ ^ — - — ■ ' '^ "V ^ A SURFACE EL. 9)9 fh hhl^ iH ^i A ^ \ '\ AK VI' v \ \ V\ A A \ 1 1 V ' A 1 V ' 'v I lOl liOl ("Ol 780 770 760 75 74 73 E-192 ^^:l^VnL..^a:v^.'^~^^ SURFACE EL. 843' V V V E-174 SURFACE EL. 760 """"■---_ /^^V>V 580 570 560 550 540 530 I I 1 I I I I I I I I > I I i«ni 1*1 E ■ -282f p* \ i\ rN SURFACE EL 629' n ^ ■\ r \ r • \ \ .s; f\. ^^ 'X \ r v ^ ^ \ N \j k 'X A H r 1 V V A/ 900 890 880 870 860 850 780 750 730 580 550 530 FLUCTUATION OF WATER TABLE AT WELLS BEAUMONT. YUCAIPA, SAN TIMOTEO, RIVERSIDE, TEMESCAL AND ARLINGTON BASINS 61 PLATE 16 Year E 3 ■*> CO ■D to d 1880 1870 I860 1850 1840 1830 (820 181 o o o C\J o o o s 2 o 1^ o CO o o O — N rt ^ 5 o m CO (0 CO CO CD CO (0 (0 10 0) (0 o at - (\J (O Tf 1 ' 1 ' 1 in E-127 SURFACE EL. 1907' A h A A / '- "1 -n x° <^''^^ /I A , ^^ — -°» k^'j^ A r ' iftA \ ■ / ■- •*o • ft. *" -- - 0) FLUCTUATION OF WATER TABLE AT WELLS BUNKER HILL and DEVIL CANYON BASINS 62 PLATE 17 Year 0) 0) (O (0 o c o -+J (0 > 90 80 70 60 50 40 30 20 I •o 0> (0 h* ® O) O w Ol (\J (VJ ■ m 10 ir N ^ s \ C- 1217a SURFACE EL 193' V li \/ \i Jj ft ^ t 1 \i f^ Iv ] vv 1 V x i V _ 90 70 60 50 H 40 30 20 — 1 E 3 (D + 60 + 50 T> + 40 CO + 30 + 20 O + 10 to 70 60 50 40 30 20 1 + 30 + 20 + 10 -10 ♦30 + 20 + 1 -1 + 20 + 1 - 1 -20 c- ii6oa4«. A ( 3-974IT 1 SURFACE EL 88' V ^ -^ y SURFACE EL 176' 1 1 - Q ^V a k ^ A •v"; IV i- rHi" % ^A i Ad ^ \ \iW/J \/ H 4j1 iV \ li m ly c-neca V X'" 1 i lOi J; ■v 1 2 C-912b ' SURFACE EL 32' I \ , aIi \\\ '\ V AAA '\ hkh \ w w % ! IV V uUVv V 1 V ' 1 i ! ' 1 i 1 V 1 ' " i 1 1 V i 1 1 ( X C -997 SURFACE EL. 56* -*w ■~ — ■ ■- > — -c o« -. o<. W^ -V V-, S . '\ f\. ft^ ■s. «v rj Vh . 1 1 1 ■vJ uni I ml I iOi ,o>, mi .0). c -1257 o. - -- -o :i -c ^c X 1 1 i r 1 ' I 1 SURFACE EU 1 2' ^J H\^\i \ AJ ^ V \i VVAA/ Ky \ 1 V «/v \l 1 1 ; 1 1 60 50 40 30 20 10 + 30 + 20 + 10 - 10 + 30 + 20 + 10 - 10 + 20 + 10 - 10 - 20 FLUCTUATION OF WATER TABLE AT WELLS EAST COASTAL PLAIN 63 PLATE 18 Year 200 E ■+> (0 ■D i/> b CO =3 0) n (0 ■*> C4- o c o -t-> CO > a; 50 40 30 20 10 r c- -124 3 V 'V V s. SURFACE EL. 40' f V "V '\ \rs >, vJ k, I f% m,i ■\, rv rx r^ ^ F Vrfjv> 'N- vJ 1 _J 1 1 FLUCTUATION OF WATER TABLE AT WELLS EAST COASTAL PLAIN 64 PLATE 19 Year E D (D "D {/) O d o c o -t-J > > ' - 10 "•' ■ — ^.;>l 8-90^ SURFACE EL no' .-20 _ ^^^^». FLUCTUATION OF WATER TABLE AT WELLS WEST COASTAL PLAIN 65 H7*oo G AREA ARY pressure zone :rence number GROUND WATER BASINS UPPER li/ALLEY SANTA ANA VALLEY EN233-F - ^ay/* I 'Xlv,_-i#E-/245 k\cx Hob I BEAUMONT NCA LLEY RIEL N IN t6 CHINO 47 LEE 17 CLAREMONT HEIGHTS 48 COL 4 8 LIVE OAK 49 BEDI 19 POMONA 20 CUCAMONGA 2la RIALTO 21b COLTON 3 13 WES 22 BUNKER HILL 31b WES 23 LYTLE 32 HOLL 24 DEVIL CANYON 33a LOS 2Sa YUCAIPA 33b MON 25b BEAUMONT 33c SAN 26 SAN TIMOTEO 33 d IRVI 27 RIVERSIDE 336 CEN 28 ARLINGTON 33f EAS' 29 TEMESCAL 34 LA 40 LOWER CAJON 3S YORI 4 1 UPPER CAJON 36 LOS 42 BEAR VALLEY 37 SAN 43 BIG MEADOWS SO SAN 44 SEVEN OAKS 45 RECHE CANYON 46 CAJALCO II7°00 STATE or CALIFORNIA DEPARTMENT OF PUBLIC WORKS DIVISION OF WATER RESOURCE lUTH COASTAL BASIN INVEST! ION OF WELLS > LE FLUCTUATION 5 10 50.000 3! 32 33 34 CHAPTER V. DISCUSSION OF ITEMS INVOLVED IN EVALUATION OF OVERDRAFT CHANGE IN STORAGE All soil from g:round surface to bed-rock contains some water at all times. Below the water table all pore space is occupied by water ; above it a laro-e part is occupied by air, but a film of water surrounds each solid particle. The amount of water, both below and above the water table, varies widely from time to time. These variations represent changes in storap'e. Since all pore space below the water table is occupied by water at all times, variation there is by vertical movement of the water table itself. When the water table rises, air is displaced by water ; when it falls only the film is retained, and air displaces the remainder. The chancre in stora^re below the water table, durin^: any period of time, occurs in the mass of alluvium lyinjr between its position at the be«iinnin«i- and at the end of the period. Just how much water this chano^e represents depends upon the ^'olume occupied by air when the water table is low, and by water when it is higrh. Two thinfrs determine this volume : first, the total pore space ; and second, the volume already occupied by water prior to a rise, or which is retained there during- and following a drop. Total pore space is a function of the grading of materials making up the alluvium. The amount of water retained is a function of both total surface area of the solid particles, and thickness of the film covering this surface. Both are greater where the material is finer. Thus, in coarse, poorly assorted materials, both total pore space and retention are relatively small, while in fine materials of more uniform shape and size both are larger. During the investigation reported in Bulletin 45, it was found that total pore space in unweathered gravels increases more rapidly with distance from the apex of an alluvial cone at the base of the mountains than does specific retention, so specific yield, i.e., the amount of water which can be put into or extracted from a unit volume of unweathered gravels, increases generally with distance from the mountains. This holds true up to the distance where the material is mostly coarse sand. As the material becomes still finer, however, specific retention increases more rapidly, and yield is again reduced. Weathering, which has acted to a varying degree on a large part of the materials which make up the valley fill, has changed total pore space little, but has reduced the size of individual particles, and so increased retention. Yield is thus reduced to a degree depending: upon the stage of weathering. Where the fresh materials were poorly assorted, and virtually complete weathering has produced clay, yield is almost negligible, being even smaller than that from silts almost equally fine which were deposited under conditions such that total pore space is larger. ( 07 ) PLATE 20 SOUTH COASTAL BASIN INVESTIGATION LOCATION OF WELLS AT WHICH WATER TABLE FLUCTUATIONS ARE SHOWN I Z» I 3° I I " I I " I CHAPTER V. DISCUSSION OF ITEMS INVOLVED IN EVALUATION OF OVERDRAFT CHANGE IN STORAGE All soil from gTOund surface to bed-rock contains some water at all times. Below the water table all pore space is occupied by water ; above it a laro-e part is occupied by air, but a film of water surrounds each solid particle. The amount of water, both below and above the water table, varies widely from time to time. These variations represent changes in storage. Since all pore space below the water table is occupied by water at all times, variation there is by vertical movement of the water table itself. When the water table rises, air is displaced by water ; when it falls only the film is retained, and air displaces the remainder. The change in storage below the water table, during any period of time, occurs in the mass of alluvium lying between its position at the beginning and at the end of the period. Just how much water this change represents depends upon the ^'olume occupied by air when the water table is low, and by water when it is high. Two things determine this volume : first, the total pore space ; and second, the volume already occupied by water prior to a rise, or which is retained there during and following a drop. Total pore space is a function of the grading of materials making up the alluvium. The amount of water retained is a function of both total surface area of the solid particles, and thickness of the film covering this surface. Both are greater where the material is finer. Thus, in coarse, poorly assorted materials, both total pore space and retention are relatively small, while in fine materials of more uniform shape and size both are larger. During the investigation reported in Bulletin 45, it was found that total pore space in unweathered gravels increases more rapidly with distance from the apex of an alluvial cone at the base of the mountains than does specific retention, so specific yield, i.e., the amount of water which can be put into or extracted from a unit volume of unweathered gravels, increases generally with distance from the mountains. This holds true up to the distance where the material is mostly coarse sand. As the material becomes still finer, however, specific retention increases more rapidly, and yield is again reduced. Weathering, which has acted to a varying degree on a large part of the materials which make up the valley fill, has changed total pore space little, but has reduced the size of individual particles, and so increased retention. Yield is thus reduced to a degree depending^ upon the stage of weathering. Where the fresh materials were poorly assorted, and virtually complete weathering has produced clay, yield is almost negligible, being even smaller than that from silts almost equally fine which were deposited under conditions such that total pore space is larger. ( 07 ) 68 DIVISION OF WATER RESOURCES As stated, storag-e chancres also occur between the highest position of the water table and the ground surface. At the surface, and in the root zone, just below, thiclaiess of film of water surrounding- each soil particle varies widely from time to time. After a protracted dry period, that near the surface may be so reduced that only hygroscopic moisture, i.e., that which adheres so closely to the soil particles that it can be removed only by the application of heat, remains. Deeper in the root zone, extractions bv vegetation and bv aeration mav reduce it almost but not quite to that extent. On the other hand, following application of suffi- cient water, the film throughout the zone is, at least temporarily, thick enough so that part of the water moves downward under the force of gravity. Between root zone and water table the minimum thickness of the film is greater, because none is extracted by plants, evaporation is negligible, and only gravity acts to reduce it. While the greater part of the removable water drains out quickly, there is generally a small long-continued downward movement in this zone. Where depth from ground surface to water table is great, variations in the amount of this Avater in transit from the surface to the water table may be material. In certain areas, too, percolating water meets with obstructions to its downward movement, in which case a localized perched water table may result, and the movement may become nearly horizontal until the water reaches a point where it can again move downward. In extreme cases, total changes in storage above the water table are great enough to com- pletely regulate a widely varying input, so that the supply as it reaches the water table is almost uniform. Because a reliable estimate of the amount of this change above the water table is virtually impossible, total changes in storage below the ground surface can be determined best for those periods in which the amount in storage above the water table is about the same at beginning and end of the periods. In the 11-year period, 1927-28 to 1937-38, inclusive, this condition should have been approximately true, because it was preceded by and ended with two wet years. The method employed in this bulletin to estimate change in storage between two positions of the water table was developed in Division of Water Resources Bulletin 45, ''Geology and Ground Water Storage Capacity of Valley Fill," and is discussed in detail in that bulletin. Briefly, the method involves five steps : (1) Specific yield of unweathered gravels at all points in the area is estimated on the basis of laboratory determinations and geologic considerations. (2) Specific yield of alluvium in various stages of weathering at all points in the area is estimated, using the values of step (1) as a basis. (3) Average specific yield of alluvium throughout the depth pene- trated by each of several groups of wells, distributed over the area, is determined from step (2), and drillers' logs of the wells. By applying tliis average value at the center of the group, a map is drawn showing lines of equal specific yield. (4) From water level measurements at wells, a map showing lines of equal change in elevation of the water table is drawn, (5) Cliange in storage in acre-feet is obtained for each of several small areas by multiplying average change in feet depth (step 4), by SOUTH COASTAL BASIN INVESTIGATION 69 average specific yield (step 3), and multiplying: the result by the area in acres. The total for the basin is obtained oy adding together the values for these increments of area. Results, so obtained, are presented in Table 5. In deriving the values, an arbitrary allowance has been made for storage changes in the large pressure areas of Central and East Coastal Plains. While piezo- metric changes in the pressure area cannot be used as in step (5), above, recent studies indicate that some change in storage does accompany change in pressure. PRECIPITATION Values of precipitation on basins, or groups of basins where they are combined for reasons stated in Chapter VI, derived as described below, are presented in Table 7. The derivation of 53-year mean precipi- tation at all stations is discussed in Chapter III. The location of lines of equal precipitation shown on Plate 21 are interpolated between the sta- tions. From this map, 53-year mean annual precipitation on the various subdivisions is estimated. Average annual precipitation for shorter periods is estimated by applying the ratio between shorter period and 53-year mean annual precipitation for the applicable group of stations, as shown in Table 6. TABLE 6. RATIOS BETWEEN SHORTER PERIOD AVERAGE ANNUAL AND 5 3 -YEAR MEAN ANNUAL PRECIPITATION Group 32-year period, 1904-05 to 1935-36, inclusive 29-year period, 1904-05 to 1932-33, inclusive 21-year period, 1922-23 to 1942-43, inclusive 11-year period, 1927-28 to 1937-38, inclusive San Fernando 1.041 San Gabriel 0.970 Raymond Basin : Valley ___ Mountain Chino 0.974 Bear Valley 0.944 San Bernardino 1.042 Riverside 1.030 Coastal Plain 0.964 1.044 1.076 1.022 0.970 0.970 0.949 1.013 1.034 1.000 1.013 1.004 1.000 0.985 0.964 0.939 0.956 0.912 0.921 1.057 1.051 1.034 1.047 1.082 1.072 0.969 1.012 0.982 70 DIVISION OF WATER RESOURCES TABLE 7. ESTIMATED AVERAGE ANNUAL PRECIPITATION ON BASINS During 5 3 -Year Period, 1883-84 to 193 5-3 6, Inclusive 3 2-Year Period, 1904-05 to 193 5-3 6, Inclusive 29-Year Period, 1904-05 to 1932-33, Inclusive 21-Year Period, 1922-23 to 1942-43, Inclusive 11-Year Period, 1927-28 to 1937-3 8, Inclusive (Acre-feet) Basin name and num.her 53-year period 29-and 32-year periods 21 -year period 11-year period A'erduso Basin (')) 8,380 San Fernando Valley Area" (1, 2, 8, 4, 38 and 39) 171,680 Raymond Basin Area Western Unit' (7 and 8a) 40,820 Eastern Unit (8b) 4,310 Glendora Basin (11) 6,080 Way Hill Basin (12) 2,880 Foothill Basin (14) 2,240 San Dimas Basin (13) 8,040 Spadra Basin (30) 6,460 Puente Basin (15) 19,540 Central San Gabriel Valley Area* (6, 9 and 10) _" 122,090 La Habra Basin (34) 32,570 Lower Los Angeles and San Gabriel Rivers area — Nonpressure* (32, 33a, 33b and 36) 97,340 Claremont Heights Basin (17) 9,740 Live Oak Basin (18) 3,390 Pomona Basin (19) 8,930 Cucamonga Basin (20) 16,460 Rialto Basin (21a) 23,790 I^wer Cajon Basin (40) 10,640 Lytle Basin (23) 6,910 Devil Canyon Basin (24) 11,420 Yucaipa Basin (25a) 27,550 Beaumont Basin (25b) 33,230 San Timoteo Basin (26) 35,170 Bunker Hill Basin (22) 83,340 Colton-Reche Canyon Area* (21b and 45) 15,310 Riverside-Arlington Area' (27 and 28) 46,080 Temescal Basin (29) 20,110 Chino Basin (16) 209,350 Irvine Basin (33d) 34,780 Lower Santa Ana River Area — Non- pressure' (33c, 35, 37 and 50) 88,400 8,750" 179,230" 41,350" 4,370" 5,900" 2,800" 2,180" 7,800" 6,270" 18,950" 118,430" 31,560" 94,320" 9,490 3,280 8,660 16,030 24,790 11,090 7,200 11,890 28,700 34,620 36,440 '^ 86,850 15,900 47,470 20,720 208,490 ' 33,530 85,220 9,020 8,570 184,720 175,450 42,210 4,460 5,900 2,800 2,180 7,800 6,270 18,950 118,430 32,960 98,500 9,390 3,280 8,660 15,870 25,010 11,190 7,260 12,000 28,950 34,920 37,490'= 87,600 16,230 49,860 21,760 210,150 «= 35,200 89,460 40,810 4,310 5,770 2,730 2,130 7,630 6,130 18,540 115,860 31,890 95,580 9,150 3,210 8,480 15,460 24,600 11,000 7,140 11,800 28,480 34,360 37,030' 86,180 16,000 49,400 21,560 205,960 = 34,160 86,800 • Basins grouped for reasons stated in Chapter VI. '' 29-year period used for these basins, 32-year period for remainder. « Weighted ratios of values from concerned groups of rainfall stations used. SOUTH COASTAL BASIN INVESTIGATION 71 MOUNTAIN AND HILL RUNOFF Records of runoff from 1904-05* to date at one point on each of three streams, San Gabriel River, Santa Ana River and San Antonio Creek, are available. From these records alone, average runoff during: the 32-year, 29-year, 21-year and 11-year periods can be determined for a considerable portion of the mountain area. Records covering the 11- and 21-year periods are available at one or more points on many other streams. While these shorter records do not cover all of the 29- or 32-year periods, average discharge for those periods can be estimated by comparison with one of the three long record stations. These estimates, next in order of reliability to actual measurements, evaluate runoff from the greater part of remain- ing mountain area. Runoff from most hill land, and from a small area of mountains adjacent to the valley, which has not been measured, is estimated from precipitation. Runoff from this area can be divided into two parts : that which flows off either so rapidly, or through such channels that it is not available to vegetation; and that which drains more slowly through the root zone, and is the residue after requirements of plants have been met. Where precipitation is heavy, the density and extent of vegetation depends upon the character of the terrain and its soil cover. In this case, total runoff is determined by consumptive use. Where precipitation is light, the type and density of vegetation is limited by water available to it. Virtually all water which does not evaporate or run off immediately is held in the soil cover and later consumed. Runoff in such cases is a function of precipitation rather than of consumptive use. The foregoing considerations, and measured and estimated runoff at gaging stations shown, provide the basis for the diagrams of Plate 22, which are used as a guide to judgment in estimating long-time mean runoff from mountain and hill areas for which no measurements are available. These comprise about 23 percent of total mountain, and 80 percent of total hill area. Shorter period runoff from the mountains is assumed to be proportional to that in one of the long record streams, that from the hills proportional to precipitation. The procedure followed in deriving values for surface inflow from directly tributary mountains and hills to each subdivision of the area, together with both surface and subsurface inflow from other subdivisions of valley areas, is described in Chapter VI. There the historic 11-year average annual values, and estimates of 21- and 29- or 32-year mean annual values under present conditions are presented. In Table 8, only the estimated long-time mean annual inflow under present conditions, and the 11-year base period average annual historic inflow used in deriv- ing the values presented in Tables 5 and 12 are shown. Except .where noted, the 21-year value is considered to be the long-time mean. • Earlier records are available but are not required for this purpose. 72 DIVISION OF WATER RESOURCES TABLE 8. ESTIMATED AVERAGE ANNUAL INFLOW TO BASINS (Acre-feet) Bdnin name mid niimher S!urface 11-year base Long-time period mean average Si iih surface' Long- time mean 11-year base period average Verdiiijo Basin (.">) 2,6:^0 2,470 San Fernando ^'alley Area'' (1. 2, 8, 4, 38 and 8J)) 40,650 35,130 Raymond Basin Are.i Western Unit'' (7 and 8a) 13,170 Eastern Unit (8b) 6,410 Glendora Basin (11) 2,550 Way Hill Basin (12) 610 Foothill Basin (14) 3,660 San Dimas Basin (13) 3,000 Spadra Basin (30) 940 Puente Basin (15) 3,830 Central San Gabriel Valley Area" (C. and 10) 131,370 La Habra Basin (34) 2,700^ I>o\ver Los Anj,'eles and San Gabriel Rivers Area — Xon pressure'' (32, 33a, 33b and 36) .__ 141.130 Claremont Heif,'hts Basin (17) 23,260 Live Oak Basin (18) 370 Pomona Basin (10) 390 Cucamonfja Basin (20) 7,870 Rialto Basin (21a) 35,190 Lower Cajon Basin (40) 15,230 Lytle Basin (23) 11,340 Devil Canyon Tiasin (24) 11,400 Yucaipa Basin (25a) 5,270 Beaumont Basin (25b) 5,750 San Timoteo Basin (26) 2.280" Bunker Hill Basin (22) 114,670 Colton-Reche Canyon Area'' (21b and 45) 36,220 35,810 Riverside-Arlinj;ton Area'' (27 and 28) 31,420 29,770 Temescal Basin (20) 8,690 7,400 Chino Basin (16) 72,760 68,490 Irvine Basin (33d) 3.880 3,770 Lower Santa Ana River Area— Non- pressure'' (33c, 35. 37 and 50) 110,280 102,860 450 11,650 5,780 2.280 400 3,190 2,780 1,080 1,080 920 710 710 3,750 1,150 1,150 122,600 13,800 13,800 2,680 123.360 36,010 36,010 22,260 310 3,320 3,320 360 4,390 4,390 7,450 33,730 15.150 12,100 10,590 5,200 5,650 2,170 6,720 6,720 113,510 31,790 34,420 20.110 20,110 3,000 25,490 2,400 20,110 20,110 3,000 22,660 2,400 • Subsurface inflow from mountains and hills included with surface inflow. '' Basins grouped for reasons stated in Chapter VI. «^ Average of 29- and 21 -year mean annual values. ^ 32-year mean annual value. IMPORT Water is imported in varying amounts to most basins, and sewage from other basins is used for irrigation in a few. A part of the imported water originates outside South Coastal Basin in Owens Valley and :\Iono Basin, Colorado River and San Jacinto Valley. Water from Colorado River, and sewage, the identity of which is maintained until its final destination is reached, are considered imports only to basins in which they are used, or commingled with other waters. Import of other water SOUTH COASTAL BASIN INVESTIGATION 73 to each basin is the total entering from immediately adjacent Dasins, no matter where it originates. The values for each year since 1927-28, presented in Chapter VI, are based primarily on measurements, and origin of the water has little bearing on the evaluation of historic 11-year average annual imports. The origin does, however, largely influence the relationship between historic and mean annual values under present conditions. The amount imported in any year from gravity sources, either mountain streams, rising water or sewage, is determined primarily by the amount available; that originating in pumping from ground water depends more upon the demand which must be satisfied from this more expensive water. This demand fluctuates with the weather, and with the amount of cheaper w^ater available, and in some cases has also shown marked progressive increase with recent cultural development. The discussion of present import to each basin, in Chapter VI, includes in each case a statement of the records used in the estimate. The values there derived, and the 11-year average values, including both water and sewage, are presented in Table 9. There is no import to those basins not included in the table. TABLE 9. AVERAGE ANNUAL IMPORT TO BASINS (Acre-feet) Z'nder Historic present during conditions, 11-year Basin name and number estimated base period San P>riiaiulo Valley Area * (1.2, 3, 4, 38 and 39 ) 308.760 " 209,690 Western Unit of Raymond Basin Area • ( 7 and 8a ) 5,910 ^ 3.480 Glendora Basin (11) 2.760 2.910 Way Hill Basin (12) 1,540 1.200 Foothill Basin (14) 160 120 San Dimas Basin (13) 5.250 3,500 Spadra Basin ( 30 ) 1,800 1.370 Puente Basin (15) — 5.640'' 4,020 -* Central San Gabriel Valley Area » (6. 9 and 10) 15.780 •* 18,250 <* La Habra Basin (34) 18.830 18,400 Lower Los Angeles and San Gabriel Rivers Area — non- pressure » (32. 33a. 33b and 36) 214.930 140.310 Claremont Heights Basin (17) 80 100 Live Oak Basin (18) 2.030 1,810 Pomona Basin (19) 4.600 3,930 Cucamonga Basin (20) 4.340 3,840 Rialto Basin (21a) 5,720 4,930 Lytle Basin (23) 10,620 10,520 San Timoteo Basin (26) 18.150 20.300 Bunker Hill Basin (22) 8,490 3,580 Colton-Reche Canyon Area « (21b and 45) 70,960 "^ 62,820 " Riverside-Arlington Area • (27 and 28) 71.5(X) " 65,330 <* Temescal Basin (29) 15.420 14.550 Chino Basin (16) 42,040 39,150 Irvine Basin C^^d) 9,440 7.300 I»\ver Santa Ana River Area — nonpressure ' (33c, 35, 37 and 50) ■ 4,680 1,320 » Basins grouped for reasons slated in Chapter VI. ^ Includes water available to Los .\ngeles Aqueduct in Mono Basin and Owens Valley. See discussion of excess lu San Fernando Valley .\rea in Chapter VI. ' Amount required to prevent overdraft, calculated ))y solnng hydrologic equation. ^ Includes sewage. 74 DIVISION OF WATER RESOURCES CONSUMPTIVE USE As implied by the term itself, consumptive use is a measure of water actually used up. In most industrial processes a very small part of the applied water goes into the product ; in some a large part of the remainder is evapo- rated ; in others the greater part, after serving its purposes in the factory, is discharged as waste, either into sewers, drains or cesspools. Only that part of the applied water which remains in the product, or is evaporated, is actually consumed. That which goes into cesspools returns to the ground water and becomes a part of it ; that discharged into drains and sewers may be available for re-use at any time before it reaches the ocean. Any of this discharged water which is not actually returned to the ground water, or otherwise held available for re-use within the basin, is considered either as a part of the surface outflow, or separately as sewage. Even though it has served a useful purpose, neither the return flow nor the outflow is a part of the consumptive use. Of precipitation which falls on roofs and other impervious surfaces, only the relatively small part which is evaporated is consumed. The remainder either flows off onto more absorptive areas, and in part percolates there, or follows impervious channels and becomes a part of the surface outflow. Generally speaking, consumptive use from areas devoted solely to industry is not very large, and since a separate determination of its amount would involve more work than seems justified, industrial areas are in most cases here treated as a part of the general municipal development. On areas occupied by natural vegetation, or devoted to agricultural crops, or to the lawns, ornamental shrubbery and trees which are an important part of urban development, it is equally true that a con- siderable part of the applied water and precipitation either runs off, or penetrates below the root zone and eventually becomes a part of the ground water. Only that part which is evaporated from the surface, transpired by plants, or remains in the growing vegetation is actually consumed. Of this, the larger part is evaporated or transpired. The type of natural vegetation which develops on an area is largely dependent upon the amount of water available. In swampy areas the supply is unlimited, and consumptive use is large. Elsewhere, native vegetation ranges from grass and weeds in areas of light rainfall, to deeper rooted brush where precipitation is greater. While some water doubtless passes below the root zone in years when precipitation is grossly in excess of average, consumptive use by native vegetation is greater in wetter years, as evidenced by more luxuriant growth, and it is probable that its average value over a long period of time is only a little less than the mean precipitation. In those areas where the water table is not close enough to the surface to support swamp vegetation, but is still high enough so that capillary water occupies a large part of the root zone, perennial grasses and weeds may develop. Since they continue to grow and use water for a much greater part of the year than do those dependent entirely upon rainfall, it is possible for consumptive use by native vege- tation in such areas to materially exceed mean precipitation. Few irrigated crops produced in South Coastal Basin are native, and the water requirement of each is fixed more by the nature of the plant itself than by its environment. Many crops are shallow-rooted, so that only a limited amount of precipitation can be stored in the root zone SOUTH COASTAL BASIN INVESTIGATION 75 for later consumption. In the case of deeper rooted plants, stored precipi- tation reduces the amount of applied water required, but has little if any effect on the total amount consumed. Thus, with irrigated culture there is no correlation between precipitation and consumptive use. Elevation of the ground water, too, generally has little influence on the amount consumed by irrigated vegetation. In the case of most crops the water table must remain below the root zone, and where the soil in that zone is kept moist by irrigation, the effect of capillarity is limited. Both irrigated grass and alfalfa, however, use more water when more is avail- able, so it is probable that elevation of the water table, where it is near the ground surface, does affect the amount consumed by those crops. Temperature and humidity have a bearing on the amount consumed by both natural and irrigated vegetation. Consumption is generally greater in inland valleys than nearer the ocean, where temperature during the growing season is lower and the atmosphere not so dry. For the same reason it varies from one inland point to another. In Chapter VI values of historic 11-year and present average annual consumptive use are derived for each subdivision of the area. The unit values used are consistent with the foregoing considerations, and with experimental research. However, the values are finally established as those which result in reasonable values of subsurface outflow, when the hydrologic equation is applied to areas above points where a measure of the reasonableness exists. Derived subsurface outflow at Los Angeles and Whittier Narrows, and from Chino into Spadra Basin, control unit con- sumptive use values assigned in the three island valleys. In Chapter VI i-easons for acceptance of the derived values are briefly discussed in con- nection with subsurface outflow from San Fernando Valley Area, Central San Gabriel Valley Area and Chino Basin. It is there shown that change in unit values of consumptive use has far greater effect upon derived subsurface outflow than upon estimated excess or overdraft. Within each valley the unit values are varied in accordance with the other considera- tions mentioned but must still be such that the derived subsurface flow is in the direction required by the slope of the ground water. On the Coastal Plain values which are consistent wdth those used inland are assigned. Deep percolation, runoff and consumptive use on unirrigated lands are all greater in wet than in dry years. In recognition of this variation, unit values assigned to unirrigated culture are different in the three periods for which consumptive use is evaluated. It is assumed that half the additional rain in the wetter period is consumed. Long-time mean values presented in Table 10 are, except where noted, based on the 21-year period. Tributary to some basins there are considerable areas of occupied or cultivated hill and mountain lands supplied with water from the valleys, or with water which would form a part of valley supply if not diverted to use before reaching it. Only that part of the precipitation on hills and mountains which runs off forms a part of the usable supply, and, in the estimate of that supply, consumptive use by native vegetation on hills and mountains has already been subtracted. Unit consumptive use by the various crops in the valleys includes that from rainfall, so unit values for hills and mountains are the differences between those for the same crops in the valleys and the precipitation which would have been con- 76 DIVISION OF WATER RESOURCES sumed on hills and mountains had the same area been occupied by native vegetation. In estimating consumptive use values, derived in Chapter VI and presented in Table 10, acreages of various crops and types of culture, as determined bv survevs carried on bv the Division of Water Resources* in 1932 and 1942, are used, it being assumed generally* that average conditions during the 11-year base period are represented by the former survey and present conditions by the latter. The principal change in culture since 1942 has been in domestic and industrial development, for which unit consumptive use is generally not greatly in excess of that for unirrigated lands and is less than that for most irrigated crops. Present consumptive use is in most cases probably little, if any, greater than it was in 1942. TABLE 10. ESTIMATED AVERAGE ANNUAL CONSUMPTIVE USE IN BASINS (Acre'feet) Basin name and number Under Historic present during conditions, 11-year estimated base period Verduffo Basin (f)) 7,580 7,440 San Fernando Valley Area' (1, 2, 3, 4, 38 and 39) 232,230 227,540 Ilavmond Basin Area Western Unit'' (7 and 8a) 36,170 36,170 Eastern Unit (8h) 3.910 3,910 (ilendora Basin (11) 6,100 6,100 Wav Hill Basin (12) 2,890 2,870 Foothill Basin (14) 2,020 1,980 San Dimas Basin (13) 8,890 8,880 Spadra Basin (30) 7,650 7,410 Puente Basin (15) 21,940 21,330 Central San Gabriel Valley Area' (6. 9 and 10) 126,800 125,940 La Habra Basin (34) 42,580" 42,670 Lower I.,os Angeles and San Gabriel Rivers Area — Xon- pressure"^ (32, 33a, 33b and 36) 90,620 90.320 Glaremont Heights Basin (17) 9,250 9,100 Live Oak Basin (18) 3,790 3,780 Pomona Basin (19) 9,650 9,630 Cucamonga Basin (20) 15,710 15,130 Rialto Basin (21a) 24,930 24,740 Lower Cajon Basin (40) 7,820 7,760 Lvtle Basin (23) 6,810 6,830 Devil Canyon Basin (24) 10,970 10,980 Yucaipa Basin '25a) 29,710 30,370 Beaumont Basin (25b) 33,380 33,290 San Timoteo Basin (26) 43,790^ 43,720 Bunker Hill Basin (22) 110,830 109,370 Colton-Reche Canyon Area' (21b and 45) 20,370 20,160 Riverside-Arlington Area' (27 and 28) 98,520 96,960 Temescal Basin (29) 34,050 32,760 Chine Basin (16) 273,740 270,460 Irvine Basin (33d) 39,990 37,330 Lower Santa Ana River Area — Nonpressure ' (33c, 35, 37 and 50) 120,920 119,970 ■ Basins grouped for reasons stated in Chapter VI. ** Average of 29- and 21-year mean annual values. '' 32-year mean annual value. * Exceptions are noted in Chapter VT, SOUTH COASTAL BASIN INVESTIGATION 77 EXPORT Export values presented in Table 11 include both water and sewage. The water may originate in imports, in diversions from mountain streams tributary to the basins, in rising water near their lower boundaries, or in wells within the basins. The general principles involved have been discussed in connection with import, and the assumptions upon which the export values for each basin are based are stated in Chapter VI. TABLE 11. AVERAGE ANNUAL EXPORT FROM BASINS (Acre'feet) Basin name and number Under Historic present during conditions, 11-year estimated base period Verdufjo Basin (5) 3,500" San Fernando Valley Area'' (1, 2, 3, 4, 38 and 39) 247,260" Raymond Basin Area " Western Unit" (7 and 8a) 11,900" Eastern Unit (81)) 2,540*= Way Hill Basin (12) 230 Foothill Basin (14) 670 San Dimas Basin (13) 2,330" Spadra Basin (30) 510" Central San Gabriel Valley Area" (6, 9 and 10) 23,100" La Habra Basin (34) 3.440" Lower Los Anj^eles and San Gabriel Rivers Area — Nonpressure'' (32, 33a, 33b and 36) 195,250" Claremont Heights Basin (17) 17,940 Live Oak Basin (18) 1,280 Pomona Basin (19) 8,860" Cucamonga Basin (20) 10,240 Rialto Basin (21a) 25,000 Lower Cajon Basin (40) 2,070 Lytle Basin (23) 17,760' Devil Canyon Basin (24) 3,170 Yucaipa Basin (25a) 1,420 Beaumont Basin (25b) 1,800'= San Timoteo Basin (26) 3,610 Bunker Hill Basin (22) 73,170" Colton-Reche Canyon Area" (21b and 45) 73,910" Riverside-Arlington Area" (27 and 28) 10,790 Temescal Basin (29) Chino Basin (16) 2,820" Irvine Basin (33d) 460" Lower Santa Ana River Area — Nonpressure" (33c, 35, 37 and 50) 16,390" 1,640" 156,340" 14,630" 2,430 140 560 1,000 200" 24,250" 2,940" 128,580" 14,200 1,170 8,630" 10,060 22,090 13,450 1,930 1,440 2,620 3,800 70,540" 67,090 • 12,760 1.270 1,930" 320" 12,390" ■ Includes sewage. *> Basins grouped for reasons stated in Chapter VI. •■ Permissible exoort calculated. SURFACE OUTFLOW Surface outflow from each basin is a mixture of water from many sources. A part of it originates in runoff from tributary mountains and hills in larg:e and small streams ; a part in precipitation on valley lands overlying or upstream from the basin ; and, where there is rising water, a portion originates in the ground water. Data upon which to base esti- mates of the amount from one source or another also vary widely in 78 DIVISION OF WATER RESOURCES location and completeness from basin to basin. Because of this diversity, outflow from each source is discussed in Chapter VI in considerable detail for each basin. In those cases where a portion of the outflow is evaluated by subtracting percolation between a gaging station and the basin boundary, from recorded daily discharges at the station, a standard percolation diagram based on the Manning Formula for flow in open channels is used. Assuming a triangular stream cross section, and perco- lation proportional to wetted perimeter, the relationship between dis- charge and percolation, as determined by substitution of equivalent items in the formula, is expressed by a straight line having a slope of three on eight if plotted on log-log paper, as illustrated on Plate 23. Its location depends upon length of reach, relation of depth to width, roughness of channel, slope and unit rate of percolation, none of these factors, however, affecting the slope of the line. If sufficient data were available to justify so doing, greater accuracy might be attained by using different curves for different periods, but in this studv one curve onlv is used in the determination for each reach. In some cases its location is established by measured percolation during a part of the period considered, in others, judgment guided by comparison with reaches elsewhere fixes its position. In the discussion in Chapter VI the curve used is determined in each case by the point on the diagram where discharge and percolation are identical. That portion of the outflow which originates on areas for which no usable stream-flow records are available is estimated as a percentage of inflow to, or of precipitation on such areas. Judgment as to the percentage used is guided by measured runoff from similar areas. Rising Water There are six general areas in South Coastal Basin in which rising water at present flows continuously. These are: (1), above Los Angeles Narrows; (2), above Whittier Narrows; (3), above Santa Ana Narrows; (4), above Bunker Hill Dike, which is the southerly boundary of Bunker Hill Basin; (5), in San Timoteo Canyon; and (6), across the Arlington- Temescal Basin boundary. This rising water constitutes part of the out- flow from the basin in which it occurs, and a regulated supply to the basin below. In all save the first area cited it is in large part diverted for use. That in Los Angeles River, while reduced by pumping from the ground water close to the Narrows, is not diverted on the surface, and because the channel is paved across the portion of the Coastal Plain in which percolation is possible, i.e., the forebay area, very little of it reaches the ground water in the Coastal Plain. In all cases, rising water occurs because the cross sectional area below the ground surface is not great enough to carry all the flow of the ground water stream which reaches it from the basin above. At many other points in the area where underflow is impeded, a steepening of the water table increases the velocity enough to offset restrictions in cross sectional area, and the water can still all flow underground. In areas of rising water, however, the slope of the water table is limited by the position and slope of the ground surface. As a result, water table and ground surface virtually coincide, not only at the restricted section, but for some distance above it. All ground water from above which cannot pass through underground with slope so fixed, drains into channels a SOUTH COASTAL BASIN INVESTIGATION 79 little below the general ground level and flows through on the surface. Any change in the quantity reaching the section results primarily in a corresponding change in the rising water. Since elevation of the water table within the rising water area cannot fluctuate greatly, most of the change is accomplished through expansion or contraction of that area. A diagram which expressed the relationship between average elevation of the water table at Wells C-294 and C-294a, near Baldwin Park, and average amount of rising water at Whittier Narrows during the year is shown on Plate 24. A similar relationship exists in San Fernando Valley, and in the basins along Santa Ana River. While it is probably true that large variations in elevation of the water table in Chino Basin would also produce some change in the rising water outflow from it, records during the past 20 years indicate no definite relationship between the two. This mav be because of the zone of dense material Iving along the south- erly boundary of the basin. Rising water from this basin varies more with fluctuations in precipitation than with changes in water table elevation. Under natural conditions rising water formerly appeared at the surface at other points where noAV, because of increased net extractions from the ground water, the flow is all below ground. It is possible that increases in supply, through conservation of water now wasting, or decreases in extractions by substitution of an imported supply, may again so increase the volume of the ground water stream that water must again flow on the surface at some of these points. Values of surface outflow presented in Table 12 include storm out- flow and rising water. Except where noted, the 21-year period determines the long-time mean. A more detailed discussion of factors involved in derivation of values for each basin or group of basins appears in Chapter VI. SUBSURFACE OUTFLOW The hydrologic equation is the algebraic expression of the natural law that all water entering an area during any period of time must either go into storage within its boundaries, be consumed therein, exported therefrom, or flow out either on the surface or underground, during the same period. Through its use, any one of the items involved is determined if all others are known. Change in storage underground in each of the basins is independ- ently evaluated herein during the 11-year base period, 1927-28 to 1987-38, only. Since this is one of the terms of the equation, all other items involved, except subsurface outflow, are independently evaluated for the same period, and subsurface outflow is determined by solving the equation. In nearly all cases considered herein, this historic base period sub- surface outflow is also considered to be the long-time mean, either arbi- trarily, as in those basins where excess or overdraft is evaluated, or because significant variation is improbable, as where rising water occurs. In five instances, however, the long-time mean under present conditions is considered to be different. These are: (1), Verdugo Basin, the sub- surface outflow from which has been virtually eliminated by the con- struction of a submerged dam in Verdugo Canyon ; and (2) , Lower Cajon, (3), Devil Canyon, (4), San Timoteo and (5), Temescal Basins, in all 80 DIVISION OF WATER RESOURCES of which subsurface outflow reacts quickly to changes in water table elevation, and in w^hich it is therefore considered that the difference in demand in the two periods is balanced by change in subsurface outflow. The values as derived in Chapter VI are presented in Table 12. TABLE 12. ESTIMATED ANNUAL OUTFLOW FROM BASINS (Acre-feet) lid sin name and n inn her Verdugo Busin (5) S;ni Fenunido Vnlley Area" (1. 2, 8, 4, 88 and 8!)) Raymond Basin Area Western I'nit '" ( 7 and 8a) Eastern Unit (81)) (Jlendora Ba.sin (11) Way Hill Basin (12) Foothill Basin (14) San Dimas Basin (18j Spadra Basin (80) Puente Basin (15) Central San (lahriel Valley Area " (6, 9 and 10) La Ha bra Basin (84) Lower Los Angeles and San (Jabriel Rivers Area- — nonpressure ■'"' (32. 38a, 881) and 80) 71),200 Claremont Heights Basin (17) 2,140 Live Oak Basin (18) 330 Pomona Basin (10) 1,180 Cucamonga Basin (20) 1,080 Rialto P.asin (21a) J),050 Tiower Cajon Basin (40) 5,200 Lytle J?asin (28) 4,060 Devil Canyon Basin (24) 4,100 Yucaipa Basin (25a) 1,820 Beanniont Basin (251)) 1.070 San Timoteo P>asin (20) 2.280'' Bunker Hill Basin (22) .88,440 •'' Colton-Reche Canyon Area" (21h and 45) ._ 20,130^ Riverside-Arlington Area" (27 an0 8,090 2,860 2,860 4,180 3,510 240 240 1.180 1.190 8,420 3,420 230 210 890 890 2,2.80 " 1,820 1,080 1,080 1,130 1,130 8.650 3,650 1,240 1,210 1,150 1,150 3,810 3,730 2,740 2.740 106,200 " 92.680 23,280 23,280 2,6J)0 ^ 2.580 5,620 5,620 85,920 3,120 300 1,140 1,200 10.210 5,240 5,430 4,250 1,300 1,040 1,740 88,1JK) 27,510 * 4.820 4.820 8,3i)0 3,890 520 520 760 760 6,560 6,560 11.880 » 13,150 590 590 5,160 • 3,950 2.920 2,920 8,800 3,8(K) 18,960 " 16.780 20,110 20,110 20,110 20.110 50.KM) 8.5.50 8,550 3,440 11,600' 8.770 83.570 3,110 3.110 3,720 6,980 6,980 21,450 WATER BAS PPER kNA VALLEY M N O 33*45' y. MONT HEIGHTS )AK lA ONGA > N R HILL CANYON »A lONT MOTEO SIDE STON CAL ! CAJON CAJON GALLEY :aoows OAKS CANYON i17'00 ATE OF CALIFORNr* NT OF PUBLIC WATER RES \L BASIN IN • UAL PRi PTH IN INCHEsi i 53 YEAl ,1883; ENDin sqooo 33 34 PLATE 21 PLATE 22 O z a: I h Q. bJ 1.6 (. 5 1.4 1.3 1.2 1. I 1.0 .9 .8 .7 .6 .5 .4 .3 .2 .1 1.7 1.6 1 .5 1.4 1.3 1.2 1.1 1.0 .9 .8 .7 .8 .5 .4 .3 .2 .1 SAN GABRIEL RIVER GROUP (29 YR. BASE PERIOD 1904-05 to 1932-33 INCLUSIVE) • 5638 / SANTA ANA RIVER GROUP 32 YR. BASE PERIOD 1904-05 to 1935-36 INCLUSIVE /J / / / 1 '/ ( / / / / / A /85( A f 1 / /4l83 A 60 • 18561 STREAM GAGING STATION ^ r- / / / / ••?/ v 'A /^ / •18261 >' / / 1 V ^ >/ / /(94jj *9 ;^ / /( M57; 882C / ►• / 7 i / / )9154 / 332 1. r A / /< 1 ' M956 / / r {/ H89S / V • V 9017 / ' / / / / / / / / / / / / / / / k 943: / lA&B / / / / ^ ^oi ' ^ ^ ^ jiy / "^ r ce 1 nt run-off 1 1 10 14 18 22 PRECIPITATION 26 30 34 INCHES 38 42 RELATION BETWEEN LONGTIME MEAN PRECIPITATION & DEPTH OF RUNOFF FOR MOUNTAIN WATERSHEDS 81 PLATE 23 I k \ a \ V E \ \ = \ \ E \ |_ L. \ E ^ \ \ — 1 V % 4 4 \ "" o\ ^ o\ 3 t^o,\:. = ^A -v.V = c^\ ^) ~ '^> L \ \\ %\ \ 'A -E \ \ \ -_ \ \ = > \ 3 \ \ = \ ' \ ~ \ \ E \ \ L E S - < \ 4 \ \ 4 CD < \ ^ \ I -^ _ » \^ \ = \ \ = "7 \ \ = o \ \ — I \ \ i ^ \ A E -J o •^ 1 a: LJ Q. iiiiiiii i \ -E umi UJi m nil illL Ullliiii iiiiliiii Ullll 1111 IIU m. 1111 llillllli llillllli llllllll 1 \ 111 IIU 1111 M 1111 nil iiiiliiii iiiilM. illlllll\ o o o. o o o o o o o UJ ll. ■ o z o o Ul I u < u o o o z UJ cr u Q. Q. D u o a. < o «o o o o o o o o o lO 133d-aN0039 NOlI.VlOD«3d PLATE 24 o CO o n o o -* CO CM • • 1943-4^ 45 CM CM 1 CO • 1 • CO Of 1 o % • 1 CO CM • 00 CO CO lO CM •37-3 39-40« • ^ 00 CM 1 CM (O CM f • t^ • 2 128-29 ro • to ro o UJ < o ± UJ CO _i UJ QQ < a. ^ z ^ O O < _i UJ OH t'6Z-D ni3M iV 3iaVl aSlVM JO NOIlVA3n3 i CHAPTER VI. DETAILED DISCUSSION OF BASINS In this chapter each basin, or group of basins in those cases where interconnection is so close as to render separate consideration meaning- less, is discussed separately. The general principles presented in preceding chapters are herein applied in the derivation of values sum- marized in Tables 5, 8, 9, 10, 11 and 12. VERDUGO BASIN ( 5 ) Verdugo Basin is located in the northeasterly portion of San Fer- nando Valley, and covers about 6.9 square miles. It is bounded on the northwest by Tujunga Basin, on the northeast by San Gabriel Mountains, on the southeast by Monk Hill Basin and San Rafael Hills, and on the southwest by Verdugo Mountains. Topography in the main portion of this basin, which lies north of Verdugo Mountains, is relatively smooth w^ith a slope to the south approximating 500 feet per mile. In the easterly part of this main portion and in Verdugo Canyon, which lies between Verdugo Mountains and San Rafael Hills, the surface is more irregular. In Verdugo Canyon the slope averages 150 feet per mile. Elevations above sea level range from 700 feet at the canyon mouth, to more than 2,000 feet along the San Gabriel Mountain boundary. Soils are mostly lighter members of the Hanford series, and are quite per- meable. Municipal development occupies a large part of the valley area, as well as portions of the hills. The local water supply, utilized to a minor extent through diver- sion from surface streams, but more through pumping from ground water, originates in precipitation on valley lands, inflow from 3,080 acres of mountains and 5,370 acres of hills directly tributary to the basin, and small inflow on the surface from Monk Hill Basin. There is no import of water or sew^age. A considerable part of surface inflow and precipitation flows out into the San Fernando Basin, and water is exported in relatively large amount to San Fernando and Monk Hill Basins. Sewage outflow is also relatively large. For this basin, long-time mean annual net supply under present conditions is somewhat less than present annual demand, so a small overdraft exists. Evaluation of items required to estimate its amount follows.* Injlotu Estimated annual surface inflow to the basin averages 2,850 acre- feet, 2,630 acre-feet and 2,470 acre-feet during the 29-, 21- and 11-year periods, respectively, as derived in Table 13. The estimate of the 29-year mean values of inflow from 3,080 acres of mountains and 5,370 acres of hills directly tributary to the basin is based on the assumption that, if water is available, average consumptive * Values of change in storage and precipitation, also required, are presented in Tables 5 and 7. (85) 86 DIVISION OF WATER RESOURCES use on the mountain area is 22 inches and that on the hill area 19 inches, inflow from the hills, however, being never less than 8^ percent of precipitation on them. Average inflow from the mountains during the ll~year base period is estimated to be 0.78 times the 29-year mean, this being the ratio between 11- and 29-year mean annual discharge of San Gabriel River. Estimated 11-year average inflow from the hills is 0.98 times the 29-year mean, being proportional to precipitation on the area as represented by the San Fernando Valley Group. Corresponding ratios for the 21-year period are 0.83 for mountains and^l.03 for hills. f The only surface inflow from other basins is that small part of the surface outflow from Monk Hill Basin which originates in the extreme westerly part of that basin. Subsurface inflow, other than that referred to by note in the table, is negligible. TABLE 13. SURFACE INFLOW TO VERDUGO BASIN Average annual for 29-year period, 1904-0 5 to 193 2-3 3, inclusive; 21 -year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38 inclusive (Acre-feet) 29-year 21-year 11-year period period period From directly tributary mountains Estimated » 1,540 From directly tributary hills Estimated » 1,100 From other basins Monk Hill 210 Total 2,850 1,280 1,200 1,140 1,080 210 190 2,630 2,470 Includes a relatively small amount of underflow. Consumptive Use In Table 14 estimates of consumptive use based on culture surveys conducted by the Division of Water Resources in 1932 and 1942 are presented. Unit consumptive use is discussed in Chapter V. Because of its topography, Verdugo Basin is best suited for domestic occupancy, and that type of culture now covers about one-half the basin. Natural vege- tation growing on the relatively large area of unused land ranges from moderately heavy brush to light brush, weeds and grass. t If runoff from hills were assumed to follow the same regimen of flow as San Gabriel River, mean annual inflow from them during the 21-year period would be 920 acre-feet and tha* during the 11-year period 860 acre-feet. SOUTH COASTAL BASIN INVESTIGATION 87 TABLE 14. ESTIMATED AVERAGE ANNUAL CONSUMPTIVE LTSE IN VERDUGO BASIN Type of culture Unit con- sumptive use, feet 1932 Acres Acre- feet 19Jt2 Acres Acre-feet 2.0 5 10 1.8 68 122 18 32 3.0 109 327 119 357 1.6 1,959 3,134 2,224 3,558 2,280 2.050 1.7 3,485 1.726 „ 3,538 1.681 3,833 4,416 4,416 — _ — _ 7,442 „ _ 7,495 — 7,416 0.3" 10 3 . 10 3 1.5" 1 2 1 2 0.1" 183 18 338 34 — 194 23 349 39 Valley area Avocado and citrus Deciduous Irrigated grass ' Domestic and industrial Unirrigated 29-year period 21-year period 11-year period Subtotal 29-year period 21-year period 11-year period Hill area Deciduous Irrigated grass Domestic and industrial Subtotal Grand total 4,610 4,765 29-year period 7,481 21-year period 7,534 11-year period 7,439 * Difference between irrigated culture and natural vegetation. Export In Table 15 estimated values of exports of water and sewage for each year since 1927-28 are presented. Export of water is to Monk Hill and San Fernando Basins, and averaged 780 acre-feet annually during the 11-year period. Sewage goes to the ocean, and averages 860 acre-feet annually. Total average annual export then was 1,640 acre-feet during the 11-year base period. It is estimated that annual export to Monk Hill Basin under present conditions is equal to the 1943-44 value. Export to San Fernando Basin, consisting of underflow diverted at the lower end of Verdugo Canyon by a submerged dam, has been high during recent years of heavy rainfall. It cannot be expected to maintain its present high value over a long time cycle of supply. It is estimated that annual export for use to San Fernando Basin under present conditions is 75 percent of the average for the eight year period, 1936-37 to 1943-44, during which rainfall in Verdugo Mountains was about 133 percent of normal. Total long- time average annual export for use from the basin under present condi- tions is estimated to be 1,470 acre-feet. The 1944-45 value of 2,030 acre-feet is considered to represent average annual sewage outflow under present conditions. Total average annual export under present conditions is therefore estimated at 3,500 acre-feet. S8 DIVISION OF WATER RESOURCES TABLE 15. EXPORT FROM VERDUGO BASIN Acre-feet Acre-feet ye«^ Water Sewage Year Water Sewage 1927-28 1,440 140 1036-37 630 1100 1928-20 1.0r>0 200 1937-3S 010 I'^OO 1929-30 1.730 840 1038-30 1.710 1650 1930-31 420 940 1939-40 1.560 1,880 1931-32 320 1,060 1040-41 1,990 2,180 1932-33 200 950 1941-42 1.870 2,160 1933-34 —90 1.080 1942-43 2,000 1,930 1934-35 440 1.090 1943-44___* 2.290 1,970 1935-36 640 1,130 1944-45 2,060 2,030 Surface Outfiotv Outflow on the surface includes part of the inflow from directly tributary mountains and hills, part of the inflow from Monk Hill Basin, and runoff originating in precipitation on the valley overlying Verdugo Basin. Inflow from mountains is distributed in several streams which flow * southward across La Crescenta Valley into Verdugo Creek, which skirts the northeasterly toe of the Verdugo Hills, and then flows southerly through Verdugo Canyon and across the basin boundary at its mouth. The channel of Verdugo Creek is paved below the debris basin near the upper end of the canyon, as are channels of most tributary streams which enter from the north above the basin. The main stream of Verdugo Creek is not paved for a distance of two and three-fourths miles above the debris basin. Percolation opportunity for mountain water and inflow from directly tributary hills is largely confined to this reach. A large part of the hill inflow enters the paved section directly, as does most of the inflow from Monk Hill Basin. Discharge at Station 3953, measured during the period 1929-30 to 1932-33, inclusive, and estimated from its relationship with Flint Wash at Station 4010 during the years 1927-28, 1928-29, and 1933-34 to 1937-38, inclusive, determines estimated 11-year average annual outflow as 820 acre-feet. This is 7.4 percent of average annual inflow to and precipitation on the basin during the 11-year period. Assuming the per- centage relationship the same for the longer periods, resultant mean annual value of surface outflow under present conditions in both 29- and 21-year periods is 860 acre-feet. Subsurface Outfiotv Assuming that all items involved have been correctly evaluated, subsurface outflow during the 11-year base period must, in accordance with principles set forth in Chapter V, have averaged 450 acre-feet annually, as derived in Table 16. Subsurface outflow is considered negli- gible under present conditions due to reconstruction in 1936 of a sub- merged dam across the lower end of Verdugo Canyon. SOUTH COASTAL BASIN INVESTIGATION 89 TABLE 16. ESTIMATED AVERAGE ANNUAL SUBSURFACE OUTFLOW FROM VERDUGO BASIN DURING THE 11 -YEAR PERIOD, 1927-28 TO 1937-38, INCLUSIVE Acre-feet Water entering basin Precipitation 8,570 Surface inflow 2,470 Subtotal 11,040 Increase in storage in basin 690 Water leaving basin on surface Surface outflow 820 Exported water 780 Exported sewage 860 Consumptive use 7,440 Subtotal 10,590 Subsurface Outflow — to San Fernando Valley Area 450 Overdraft Assuming that the 21-year period is the cycle of long-time mean supply, estimated annual overdraft is 240 acre-feet, as derived in Table 17. In this basin substitution of 29-year mean values results in the same answer. TABLE 17. ESTIMATED ANNUAL OVERDRAFT IN VERDUGO BASIN UNDER PRESENT CONDITIONS ASSUMING THE 21 -YEAR PERIOD, 192 2-23 TO 1942-43, INCLUSIVE, TO BE ONE OF LONG-TIME MEAN SUPPLY (Acre-feetJ Estimated Actual long-time 11-year mean annual base under period present average Differ- conditions annual ence Average annual rise in storage during base period 690 Items tending to increase the rise Precipitation 9,020 8,570 450 Surface inflow 2,630 2,470 160 Subtotal to be added 610 Items tending to decrease the rise Consumptive use 7.580 7,440 90 Export 3,500 1,640 1,860 Surface outflow 860 820 40 Subsurface outflow 0* 450 — 450 Subtotal to be subtracted 1,540 Overdraft 240 i Subsurface outflow reduced to negligible amount by submerged dam at lower end of Verdugo Canyon rebuilt and enlarged in 1936. 90 DIVISION OF WATER RESOURCES SAN FERNANDO VALLEY AREA San Fernando Basin ( 1 ) Sylmar Basin ( 2 ) Tujunga Basin (3) Pacoima Basin (4) Bull Canyon Basin (38) Little Tujunga Basin (39) All of these eonti«:iious basins, with the exception of Bull Canyon and Little Tujunga from which extractions are nei?ligible and for w^hich available data are very meager, lie almost entirely within the City of Los Angeles, and have available to them the large supply imported through the Owens Valley-Mono Basin Aqueduct. For this reason they are treated as a unit. Topography varies greatly from one basin to another. The surface of San Fernando Basin is relatively smooth, with gentle slope to the south toward Los Angeles River over the westerly three-quarters of the basin, and steeper slope in the same direction adjacent to Verdugo Mountains, north of and including part of Burbank and Glendale. Sylmar Basin is also relatively smooth, with average slope to the south ranging between 90 and 160 feet per mile. Along its southwest boundary the land is rolling. In the westerly one-third of Tujunga Basin the valley surface shows no large irregularities, but is cut by many small channels. Slope here is to the south and averages 75 feet per mile. The middle third is in large part covered by the w^ash of Tujunga Creek, and slope is to the west also at about 75 feet per mile, with a relatively narrow strip of usable land which slopes steeply to the south. East of Tujunga Creek the basin occupies the westerly extremity of the long depression between Verdugo and San Gabriel Mountains. Here the slope is to the west at an average rate of 200 feet or more to the mile. In the west and north central portions of Pacoima Basin topography is smooth but steep, with slope toward the south ranging from 180 to 300 feet per mile. Elsewhere the land is rolling, and east of Pacoima Creek the same folded but water-bearing beds which underlie Bull Canyon and Little Tujunga Basins result in steep and irregular topography. Topography of Bull Canyon Basin is more rolling than that of Pacoima Basin, while that of Little Tujunga Basin is more rugged. Elevations above sea level in San Fernando Valley Area range from about 400 feet at the lower boundary of San Fernando Basin, to 3,200 feet at the highest point in Little Tujunga Basin. Soils and general cultural development have been discussed in Chapter II. The local water supply, utilized to a minor extent through diversion from surface streams, but more through pumping from ground water, originates in precipitation on valley lands, inflow from 212 square miles of mountains and 65 square miles of hills directly tributary to the basin, and surface inflow from Verdugo Basin. In addition to the large supply from the Owens Valley-Mono Basin aqueduct of the City of Los Angeles, water is imported from Verdugo Basin, and from Colorado River by the Metropolitan Water District. A considerable part of the surface inflow and precipitation flows out into the Coastal Plain, and w^ater originating in both local and Owens Valley-Mono Basin sources is exported in large amount to West Coast, Hollywood, Los Angeles Narrows, and Main San Gabriel Basins and to Los Angeles and Montebello Forebay Areas. Sewage outflow is also large. SOUTH COASTAL BASIN INVESTIGATION 91 For the area as a whole, and for each of its component basins, long- time mean annual net supply under present conditions is grreater than present annual demand, so an excess exists. Evaluation of items required * to estimate its amount follows. Inflotu Estimated surface inflow to the area averages 49,670 acre-feet, 40,650 acre-feet, and 35,130 acre-feet annually in the 29-, 21- and 11-year periods, respectively, as derived in Table 18. Inflow from directly tributary mountain and hill area, above gaging stations at which flow was measured during period of several years, is tabulated below. Twenty-nine year mean annual values for Pacoima and Tujunga Creeks, and both 29- and 21-year values for Haines Creek, are estimated by comparison with San Gabriel River. One year of missing record for Haines Creek during the 11-year period is estimated by com- parison with Big Tujunga Creek. Average annual runoff of Sycamore Canyon for all three periods is estimated by comparison with San Gabriel River. Mean annual infloxc in acre-feet 29-i/ear 21-year 11-year Stream Station period period period Pacoima Creek 6006 8,770 • 6,660" r),590" Haines Creek 5028 150 120 80 Tujunj?a Creek 612i)-80 26,810« 21.200'> 17,480" Sycamore Canyon 3974 370 310 290 Total 36,100 28,290 23.440 » Measured runoff adjusted for change in reservoir storage, but not corrected for reservoir evaporation. •* Actual runoff, uncorrected for reservoir operation. The estimate of 29-vear mean annual inflow from 48,510 acres of mountains directly tributary to the area, and draining in below gaging stations, and from 40.100 acres of tributary hills is based on the assump- tion that, if water is available, average annual consumptive use on both mountain and hill area tributarv to San Fernando and Svlmar Basins is 20 inches, and on that tributary to Tujunga, Pacoima, Bull Canyon and Little Tujunga Basins, 19 inches. However, it is further assumed that runoff is never less than 8 and 8^ percent of precipitation on that area tributary to the two groups of basins, respectively. Inflow from mountains during the 11-year base period is estimated to be 0.78 times the 29-year mean, this being the ratio between 11- and 29-year mean annual discharge of San Gabriel River. Estimated ll-vear mean annual inflow from hills is 0.98 times the 29-year mean, being proportional to precipitation on the area represented by the San Fernando Valley Group. Corresponding ratios for the 21-year period are 0.83 for mountains and 1.03 for hills. t Inflow on the surface from other basins consists of outflow from Verdugo Basin. Subsurface inflow, other than that indicated by note in Table 18, is estimated to be negligible under present conditions. The submerged dam across the lower end of Verdugo Canyon was reconstructed in 1936, * Values of change in storage and precipitation, also required, are presented in Tables 5 and 7. • t If runoff from hills is assumed to follow the same regimen of flow as San Gabriel River, mean annual inflow during the 21-year period is reduced to 3,970 acre-feet, and for the 11-year period to 3,730 acre-feet. 27,980 6,580 23,150 6,190 310 4,920 290 4,680 860 820 92 DIVISION OF WATER RESOURCES and since that time nearly all underflow has been diverted for nse. During: the 11 -year period it averaged 450 aere-feet annually. TABLE 18. SURFACE INFLOW TO SAN FERNANDO VALLEY AREA Average annual for 29-year period, 1904-0 5 to 9 3 2-33, inclusive; 21 -year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38 inclusive (Acre-feet) 29-year 21-year 11-year period period period From directly tributary mountains Measured durinjj all or part of period 35,730 All estimated" 7,930 From directly tributary hills Measured durinji: part of period 370 All estimated ^ 4,780 From other basins Verdujro 860 Total 49,670 40,650 35,130 " hu-ludes a relatively small .imount of underflow. Import In Table 19 estimated values of imports of water for each year since 1927-28 are presented. There is no sewag:e import. During the 11-year period, an annual average of 209,690 acre-feet of water was imported, 208,920 acre-feet from the Owens Valley by the City of Los Angeles, and the remainder from Verdugo and Los Angeles Narrows Basins. Los Angeles Aqueduct imports in 1948-44 and 1944-45 were 274,500 and 266,370 acre-feet, respectively. The long-time mean quantity which can be imported with present facilities in the Owens Valley-Mono Basin Aqueduct is estimated to be 807,000 acre-feet annually. Since this amount can be brought in at little additional cost, it is considered to be the import from that source under present conditions. Imports from Colorado River bv the Metropolitan Water District started in 1940-41, when 820 acre-feet were brought in. In 1942-48, 1,200 Hcre-feet were imported, in 1948-44, 710 acre-feet, and in 1944-45, 580 acre-feet. The 1948-44 value is assumed to be average annual import from this source under present conditions. Imports from Los Angeles Narrows Basin have remained approxi- mately constant, and for present conditions are assumed to equal the average for the 11 -year period. Imports from Verdugo Basin consist of underflow diverted at a submerged dam at the lower end of Verdugo Canyon, and have been high during recent years of high water table and heavv rainfall. Thev cannot be expected to maintain their present high value over a long-time cycle of supply. It is estimated that annual average import from this source luider present conditions is 75 percent of the average for the eight years of record, 1986-87 to 1948-44, inclusive, during which rainfall in Verdugo ^Mountains averaged 188 percent of normal. Total import to San Fernando Valley Area under present conditions is estimated to be 808,760 acre-feet annual 1 v. SOUTH COASTAL BASIN INVESTIGATION 93 TABLE 19. IMPORT TO SAN FERNANDO VALLEY AREA Year Acre-feet Year Acre-feet Year Acre-feet 1927-28 190,230 1933-34 lSr),480 1939-40 218,r)00 1928-29 192,140 1934-35 19r),280 1940-41 203,600 1929-30 199,920 1935-30 237,590 1941-42 248,11M) 1930-31 216,220 1936-37 206.780 1942-43 207.190 1931-32 238,500 1937-38 209.780 1943-44 277,070 1932-33 228,620 1938-39 238,770 1944-45 268.600 Consumptive Use In Table 20 estimates of consumptive use based on culture surveys conducted by the Division of Water Resources in 1932 and 1942 are pre- sented. Areal distribution of irri Grand total 1.32.998 1.33.875 29-year period 231,419 21-year period 2.32.227 11-year period 227,541 » Difference between irrigated culture and natural vegetation. •^ Difference between reservoir evaporation and natural corisumptive use from same area. 94 DIVISION OK WATER RESOURCES Export In Table 21 estimated values of exports of water and sewage for each year since 1927-28 are presented. During the 11-year period, 1927-28 to 1937-38, inclusive, an annual average of 150, 560 acre-feet of water was exported for use. Sewage outflow from the area averaged 5,780 acre- feet annually. Total average annual export then was 156,340 acre-feet during the 11-year base period. Estimated total average annual export under present conditions is 229,590 acre-feet of water and 17,670 acre-feet of sewage, a total of 247,260 acre-feet, equal to the value for 1944-45. TABLE 21. EXPORT FROM SAN FERNANDO VALLEY AREA (Acre-feet) Year Water Sewage Year Water Sewage 1027-28 188,970 1,8()0 1086-87 168,680 0,080 1028-20 14.1.180 2,020 1087-88 160.660 0,880 1020-80 146,880 8,670 1988-80 177.040 10,870 1080-81 ir)8,480 4,800 1080-40 174,080 11,670 1081-82 ir>2,810 r),.-)20 1040-41 174,480 IfvlOO 1082-88 148,140 r>,6(M) 1041-42 180,440 15,510 1088-84 140,070 5,700 1042-48 108,200 16.540 1084-85 187,450 7,240 1048-44 216,850 17.870 1085-86 150,000 7,810 1944-45 229,500 17,670 Surface Outflotv Estimated surface outflow from the area averages 24,450 acre-feet, 22,040 acre-feet and 20,360 acre-feet annually in the 29-, 21- and 11-year periods respectively as derived in Table 22. Virtually all outflow is in Los Angeles River. This stream has been measured since 1929-30 at Station 2771, four miles downstream from the San Fernando Basin boundary, where, during the 11-year period out- flow is estimated to have averaged 21,850 acre-feet per year. Prom low flow measurements it is further estimated that 3,320 acre-feet of this was rising water*, and 18,530 acre-feet storm outflow. In 1937-38 esti- mated rising water increased abruptly to about 22,000 acre-feet annually, and has been large since then. This increase is presumed to be partly due to higher water table in the area north of the river, and partly to recent lowering of the river channel for flood control improvements. A portion of the outflow originates in mountains and varies with mountain runoff. By application of percolation curves, and use of daily discharges of Tujunga and Pacoima Creeks near points where they emerge from the mountains, the ratio between 29- and 11-year average discharge from these streams into Los Angeles River is estimated as 1.36. It is also estimated that approximately one-third the average discharge at Station 2771, below the valley boundary, originates in mountains, and two-thirds in hills and on valley lands, outflow from which should vary approxi- mately with precipitation on them. By giving the ratio between 29- and 11-year average precipitation, i.e., 1.02, twice the weight assigned the above 1.36 ratio, it is estimated that 29-year mean annual discharge at Station 2771 under present conditions, exclusive of rising water, is 13 percent greater than the 11-year average, or 20,940 acre-feet. On the same basis, difference between 11- and 21-year mean is negligible. SOUTH COASTAL BASIN INVESTIGATION 95 Only a few records of operation of Hansen and Sepulveda Reservoirs are as yet available, and there is some uncertainty as to future operation. Their effect on outflow from the area under present operation is believed small, and has not been numerically evaluated. Average annual precipitation on hills and valley land tributary to Los Angeles Narrows Basin above Station 2771 and below the valley boundary, varies but little in the three periods, and contribution to out- flow from that source in both 29- and 21-year periods is estimated to be the same as that during the 11-year period, i.e., 1,490 acre-feet. The amount of rising water in any year, and over a long period of years, not only varies with elevation of the water table in San Fernando Basin, but is affected by the amount of extraction near the Narrows, and by recent lowering of the channel. It is arbitrarily assumed that average elevation of the water table may be so reduced that the long-time mean annual value for rising water is 5,000 acre-feet. TABLE 22. SURFACE OUTFLOW FROM SAN FERNANDO VALLEY AREA Average annual for 29-year period, 1904-05 to 1932-33, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38 inclusive (Acre-feet) 29-year 21-year 11 -year period period period Measured durinj; part of period Storm outflow 20,940 Rising: water 5,()(K) Subtotal 2r»,940 Estimated, originating in Precipitation on hills and valley land above Station 2771 and below valley boundary 1,490 Remainder 24.450 22,040 20,300 Excess Assuming that the 21-year period is the cycle of long-time mean supply, estimated annual excess is 25,-190 acre-feet, as derived in Table 28. If the 29-year mean values are substituted, the derived value is 27,420 acre-feet. The foregoing figures are predicated on two assumptions : First, that the 1944-45 value represents "present" export, and second that the average maximum amount which can be brought in through the Owens Valley-Mono Basin Aqueduct annually during a period of long-time mean supply represents ' ' present ' ' import from that source. Under the second assumption, aqueduct water is treated as part of the local supply. This is logical for several reasons: (1) The greater part of the directly used supply to the area comes from that source; (2) A considerable part of the deep percolation into the area is aqueduct water, or results from its use on the surface; (3) All local water, as well as aqueduct water, is available to the city when needed; (4) Wide variation in aqueduct flow in recent years, from 185,600 acre-feet in 1933-34 to 274,500 acre-feet in • Includes relatively small amounts of industrial wastes, discharge from distribu- tion lines, etc. i8.r»Ho 18,530 r).()(K) 3.320 28,r»3() 21,850 1,490 1,490 96 DIVISION OF WATER RESOURCES 1943-44, makes it extremely difficult to establish a value for "present" import comparable to those established in other basins; (5) So long as the required water is available in Owens Valley and Mono Basin, and can be brought in with present facilities, no overdraft can develop. The excess is of course actually in Owens 'Valley and Mono Basin, rather than in San Fernando Valley Area. As is true of an excess from local sources it must, if brought in and spread in the valley over a period of years, add to outflow as rising water until such time as it is needed. It differs from excess local water, however, in that it can be used or wasted before reaching the area, or can be wasted directly into Los Angeles River, in which case it would have little or no effect on the average elevation of the water table or the amount of rising water. TABLE 23. ESTIMATED ANNUAL EXCESS IN SAN FERNANDO VALLEY AREA UNDER PRESENT CONDITIONS ASSUMING THE 21-YEAR PERIOD, 1922-23 TO 1942-43, INCLUSIVE, TO BE ONE OF LONG-TIME MEAN SUPPLY (Acre-feet) Estimated Actual long-time 11-year mean annual base under period present average Differ conditions annual ence Avcrajjp annujil ri.se in storajje durinj; base period — 9,370 Items tendiiif? to increase the rise Precipitation 184,720 175.450 9.270 Surface inflow — ____ 40,650 35,130 5,520 Subsurface inflow 450 — 450 Import 308,760 209,690 99,070 Subtotal to be added 113,410 Items tending to decrease the rise Consumptive use 232,230 227.540 4,690 Export 247.200 156,340 90,920 Surface outflow 22,040 20,360 1,680 Subtotal to be subtracted 97,290 Excess 25,490 Subsurface Outflow Assuming that all items involved have been correctly evaluated, subsurface outflow during the 11-year base period must, in accordance with principles set forth in Chapter V, have averaged 7,110 acre-feet annually, as derived in Table 24. By comparison with independently determined underflow at Whittier Narrows and Santa Ana Narrows, 7,110 acre-feet average annual subsurface outflow at Los Angeles Nar- rows, while possibly a little high, is not far enough out of line to be significant so far as evaluation of excess is concerned. An increase of 0.1 foot in value of unit consumptive use assigned garden and field crops would decrease calculated subsurface outflow by 2,040 acre-feet, and estimated excess by only 60 acre-feet. A similar increase in value for unirrigated lands would decrease subsurface outflow 4,910 acre-feet, and increase excess by a little less than 700 acre-feet. SOUTH COASTAL BASIN INVESTIGATION 97 TABLE 24. ESTIMATED AVERAGE ANNUAL SUBSURFACE OUTFLOW FROM SAN FERNANDO VALLEY AREA DURING THE 11 -YEAR PERIOD, 1927-28 TO 1937-3 8, INCLUSIVE Acre-feet Water entering San Fernando Valley Area Precipitation 175,450 Surface inflow 35,130 Subsurface inflow 450 Import 209,690 Subtotal 420,720 Increase in storage 9,370 Water leaving on surface Surface outflow 20,360 Exported water 150,560 Exported sewage 5,780 Consumptive use 227,540 Subtotal 413,610 Subsurface Outflow — to Los Angeles Narrows Basin 7,110 WESTERN UNIT OF RAYMOND BASIN AREA Monk Hill Basin (7) Pasadena Sub-area (8a) This area is operated as a unit in administration of Raymond Basin Watermaster Service Area, and is so treated here. It is located in the northwest portion of San Gabriel Valley, and covers about 36 square miles. It is bounded on the southwest and west by San Rafael Hills, on the northwest by Verdugo Basin, on the north and northeast by San Gabriel Mountains, on the east by Eastern Unit of Raymond Basin Area, and on the southeast and south by Raymond Fault, across which lies Main San Gabriel Basin. Topography is for the most part fairly smooth, but exhibits some irregularity along Arroyo Seco, in the upper reaches of Eaton Creek, just north of the westerly one-third of Raymond Fault, and •in portions of the La Crescenta trough. The slope is generally to the south, and ranges from 100 feet per mile in the lower portions to 300 feet per mile near the mountains. Elevations above sea level range from 500 feet near the southeasterly corner of Pasadena Sub-area, to 1,800 feet in the westerly portion of Monk Hill Basin. Soils covering the area are about equally divided between lighter members of the Hanford and Ramona series, with a few scattered areas of Placentia soils. Hanford soils predominate in Monk Hill Basin and on either side of Eaton Wash and Arroyo Seco, while Ramona soils cover most of the west central por- tion of Pasadena Sub-area. Municipal development occupies about 60 percent of the area, about 10 percent is devoted to agriculture, and the remainder is in a more or less natural state being covered by trees, brush, weeds and grass. The local water supply, utilized to a considerable extent through diversion from surface streams, but more through pumping from ground water, originates in precipitation on valley lands, and inflow from 23,170 acres of mountains and 1,750 acres of hills directly tributary to the area. Imported water provides a relatively large addition to the supply. 7—71061 98 DIVISION OF WATER RESOURCES A considerable part of the surface inflow and precipitation flows out into Los Angeles Narrows and Main San Gabriel Basins, together with some underflow, and there is small surface outflow to Verdugo Basin. Water is exported in relative^ large amount to Main San Gabriel Basin, and in lesser quantity to Los Angeles Narrows Basin. Sewage outflow is also relatively large. Water rights in the Western Unit of Ravmond Basin Area have recently been adjudicated,* and extractions are now limited to safe yield. This eliminates the possibility of overdraft, which under conditions as of 1937-38 amounted to 6,000 acre-feet annual^. The court retains juris- diction, so that future adjustments in rights may be made when necessary due to changed conditions. The court appointed the Division of Water Resources as Watermaster, and service started July 1, 1944. With two exceptions, all major producers from the area have signed a water exchange agreement. Under this plan, any entity which does not need all water available to it under its decreed right, or which can import additional water, offers its surplus water from sources within the area for sale on a year-to-year basis to those parties whose rights are not suffi- cient to meet their demands. Thus, deficit in supply is made up by some decrease in exports, and an increase in imports. Present demand, for use within the area and for export, is greater than available local supply. This necessitates import of considerable mag- nitude. The long-time mean annual amount of this import under present conditions is estimated herein. Evaluation of items required t for this estimate, follows. Inflow Estimated annual surface inflow to the unit averages 15,620 acre-feet, 13,170 acre-feet and 11,650 acre-feet in the 29-, 21- and 11-year periods, respectively, as derived in, Table 25. Annual inflow in Arroyo Seco, from above Station 5127 at which flow was measured during all or part of each period, averages 7,770 acre-feet, 6,610 acre-feet, and 5,730 acre-feet during the three periods. That in Eaton Creek above Station 4090 averages 3,510 acre-feet, 2,900 acre-feet and 2,450 acre-feet. For Arroyo Seco the 29-year mean annual value is derived by comparison with San Gabriel River, while for Eaton Creek it is estimated by comparison with San Gabriel River and Arroyo Seco. The estimate of 29-year mean annual inflow from mountains and hills directly tributary to Monk Hill Basin, and downstream from Station 5127 is based on the assumption that, if water is available, average annual consumptive use from mountain area is 21 inches, and that from hill area 19 inches, inflow however never being less than 7J percent of precipi- tation on mountains and 8^ percent of that on hills. For areas tributary to Pasadena Sub-area below Station 4090, consumptive use on mountains is assumed to be 20 inches, and that on hills 18 inches. Average inflow from mountains during the 11-year period is estimated to be 0.78 times the 29-year mean, this being the ratio between 11- and 29-year mean discharge of San Gabriel River. That from hills is 0.99 times the 29-year mean, being proportional to precipitation on the area represented by the * City of Pasadena v. City of Alhavihra. et ah, Case No. Pasadena C-1323, Superior Court, Los Angeles County, December 23, 1944. t Values of change in.storage and precipitation, also required, are presented in Tables 5 and 7. SOUTH COASTAL BASIN INVESTIGATION 99 Raymond Basin Group. Corresponding ratios for the 21-year period are 0.83 and 1.02.* Subsurface inflow, other than that indicated by note in Table 25, is negligible. TABLE 25. SURFACE INFLOW TO WESTERN UNIT OF RAYMOND BASIN AREA Average annual for 29-year period, 1904-05 to 1932-33, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38 inclusive (Acrerfeet) 29-year 21-year 11-year period period peirod Fz'om directly tributary mountains Measured during all or part of period 11,280 9,510 8,180 All estimated =* 3,980 3,300 3,110 From directly tributary hills All estimated * 360 360 360 Total 15,620 13,170 11,650 ^ Includes a relatively small amount of underflow. Historical Import In Table 26, estimated values of imports of water for each year since 1927-28 are presented. There is no sewage inflow. Water is now^ imported from Eastern Unit of Raymond Basin Area, Verdugo Basin, San Gabriel Basin, and Colorado River. From 1933-34 to 1940-41, inclusive, water was imported from Morris Reservoir on San Gabriel River. During the 11-year period a total annual average of 3,480 acre-feet was imported. TABLE 26. IMPORT TO WESTERN UNIT OF RAYMOND BASIN AREA Year Acre-feet Year Acre-feet Year Acre-feet 1039-40 13,990 1940-41 6,240 1941-42 1,320 1942-43 1,080 1943-44 3,460 1944-45 6,560 1927-28 460 1928-29 470 1929-30 560 1930-31 600 1931-32 580 1932-33 580 1933-34 5,330 1934-35 7,830 1935-36 2,230 1936-37 7,190 1937-38 12,400 1938-39 13,600 Consuviptive Use ' In Table 27 an estimate of consumptive use, based on a detailed culture survey conducted by the City of Pasadena in 1935, 1938 and 1939, is presented. Unit values were estimated largely from soil moisture tests. Culture is mostly of municipal type, the cities of Pasadena and San. Marino, together with their unincorporated suburbs, occupying the greater part of the area. Industrial development is small. Natural vege- tation growing on unused lands is mostly light brush, weeds and grass, with a few areas covered bv trees and undergrowth. * If inflow from hills is assumed to follow the same regimen of flow as San Gabriel River, inflow during- the 21- and 11-year periods as estimated at 300 and 280 acre-feet respectively. 100 DIVISION OF WATER RESOURCES Change in consumptive use due to cultural development has been small enough so that the value derived in the table is considered average for present conditions as well as for the 11-year period. TABLE 27. ESTIMATED AVERAGE ANNUAL CONSUMPTIVE USE IN WESTERN UNIT OF RAYMOND BASIN AREA Cultural classification Unit consumptive use, feet Acres Acre- feet Estates Class A residential. Class B residential-- Ilural residential Commercial Semicommercial Reservoir sites Parks Schools Lawns Lawn and shrubs Lawn and trees Shrubs Ornamental trees Avocado and citrus. Deciduous Truck and nursery_- Vineyard Brush Vacant Riverwash Streets Totals 2.07 2,604 5,390 1.92 2,167 4,160 1.88 3,170 5,960 1.78 765 1,362 0.50 193 96 1.32 532 702 1.34 63 84 2.40 453 1,087 1.63 272 443 3.00 4 12 3.00 1 3 3.33 63 210 2.33 4 9 1.58 1,481 2,340 2.00 904 1,808 1.75 294 514 3.00 296 888 1.67 1,024 1,710 1.67 2,275 3,799 1.50 2,252 3,378 0.99 354 351 0.50 3,722 1,860 22,893 36,166 Export In Table 28 estimated values of water and sewage exported for each year since 1927-28 are presented. Water is exported to Main San Gabriel and Los Angeles Narrows Basins, w^hile sewage is discharged into Rio Hondo in Main San Gabriel Basin. During the 11-year period an annual average of 9,500 acre-feet of water and 5,130 acre-feet of sewage, a total of 14,630 acre-feet, was exported. Export of water, by all but one exporter, is now limited to decreed rights unless additional water is purchased by exporters under the Water Exchange Agreement. It is estimated that average annual export under present conditions is 4,620 acre-feet, determined as follows. Export to Los Angeles Narrows Basin is assumed to equal the amount actually exported in 1944-45. The estimate of average annual export to Main San Gabriel Basin under present conditions is based upon decreed rights of exporters, use of water in exporters' service areas wdtliin the Western Unit in 1944-45, and amounts offered for sale by exporters under the Water Exchange Agreement for the Fiscal Year 1946-47. Annual export of sewage under present conditions is assumed to equal that of 1944-45, jor 7,280 acre-feet. Estimated total annual export under present conditions then is 11,900 acre-feet. SOUTH COASTAL BASIN INVESTIGATION 101 TABLE 28. EXPORT FROM WESTERN UNIT OF RAYMOND BASIN AREA Acre-feet Acre-feet Year Water Sewage Year Water Sewage 1927-28 10,610 4,260 1036-37 S.OOO 5,730 1928-29 10,110 4,660 1937-38 7,710 5,920 1929-30 10,200 4,650 1938-39 8,260 6,060 1930-31 10,400 4,900 1939-40 8,860 6,170 1931-32 9,580 5,320 1940-41 8,410 6,490 1932-33 9,570 5,070 1941-42 9,140 6,340 1933-34 10,320 5,140 1942-43 9,720 6,550 1934-35 8,300 5,300 1943-44 8,860 6,970 1935-36 9,650 5,470 1944-45 6,390 7,280 Surface Out flow Outflow on the surface includes part of the inflow from directly tributary mountains and hills, and runoff originating in precipitation on valley lands within the area, and is estimated to average 11,580 acre-feet, 10,360 acre-feet and 8,090 acre-feet annually in the 29-, 21- and 11-year periods, respectively, as derived in Table 29. The greater part of inflow from directly tributary mountains, as well as a considerable part of that originating elsewhere, is in Arroyo Seco and Eaton Creek. Parital regulation of flood flows is provided in Devils Gate Keservoir on Arroyo Seco at the lower boundary of Monk Hill Basin and in Eaton Wash Reservoir on Eaton Creek one and one-half miles above Colorado Street. ARROYO SECO Outflow in Arroyo Seco has been measured since 1925-26 at Station 4035 at the lower boundary of the area, with exception of 1927-28 and 1928-29 during which years there was no release from Devils Gate Reser- voir, and for which years outflow is estimated by comparison with Seco Drain. During the 11-year period, estimated outflow in Arroyo Seco averaged 2,620 acre-feet annuallj^ Best available information indicates that in the immediate future Devils 0ate Reservoir will be operated principally for flood control, with little storage of water for conservation. In the past, conservation storage has amounted to about 25 percent of capacity during winter flood months, with no limit after April 15th. Henceforth, except for temporary detention of large flood flows, it is probable that the greater part of the water reaching the reservoir in suitable volume will be used for sluicing debris from behind the dam. To compensate for resultant loss of conserva- tion in the reservoir, it is assumed that maximum spreading will be resorted to upstream. Below Devil's Gate to the lower boundary of the area the channel of Arroyo Seco is completely lined, except for a confined section one-quarter mile long just below the dam, where percolation is considered negligible. Twenty-nine and 21-year mean outflow under present conditions, of water originating in upper Arroyo Seco sources, is estimated as follows. Mean daily discharges of Arroyo Seco at Station 5139B, just above the point of diversion by Pasadena Water Department, were measured from 1923-24 through 1931-32. For other years from 1913-14 through 1942-43, except 1915-16, mean daily discharges at this station are estimated by 102 DIVISION OF WATER RESOURCES comparison with flows at Station 5127. one and one-half miles upstream. Of mean daily flows past Station 5139B, it is assumed that all flows up to 20 second-feet are diverted for use, but that no diversion is made when discharge is in excess of 100 second-feet. It is further assumed that, of mean daily flovv^s past the diversion point, all up to 150 second-feet are added to the ground water by artificial spreading and natural percolation between the diversion point and reservoir, but that no spreading is done when flows exceed 150 second-feet. Natural percolation between canyon mouth and reservoir is estimated by use of a percolation curve with 20 second-feet all percolating. For those years of the 29-year period prior to the beginning of record^at Station 5127, and for 1915-16, outflow from these upper Arroyo Seco sources is estimated by comparison with San Gabriel Eiver. Additional outflow in Arroyo Seco originating on areas draining in below Station 5139B, is considered m five parts, in the first four of which sufficient record is available to esablish a relationship between outflow and precipitation at valley stations of the Kaymond Basin Group, by means of which outflow during years of missing record is estimated. (1) Runoff in Altadena Storm Drain, which enters Arroyo Seco one- eighth mile below Station 5139B, was measured at Station 5139C from 1925-26 to 1932-33, inclusive. It is assumed that, of monthly discharges in excess of 20 acre-feet, one-half constitutes outflow. (2) Flows from Flint Wash, measured at Station 4010 from 1923-24 to date, and from (3) West Altadena Storm Drain, measured at Station 4021A from 1937-38 to date, enter immediately above Devils Gate Dam, with so little perco- lation opportunity that all runoff there is assumed to constitute outflow from the unit. (4) Outflow from sources tributary below Devil's Gate, under conditions the same as at present, has been measured from 1937-38 to date by the difference between releases from the reservoir and flows at Station 4035. (5) Unmeasured outflow from areas tributary to Devil's Gate below gaging Station 5139B is estimated to be all of the inflow from 240 acres of hills, 50 percent of that from 14 acres of mountains, and 6 percent of the precipitation on 810 acres of valley land. Resultant estimated annual surface outflow in Arroyo Seco under present conditions averages 6,180 acre-feet during the 29-year period and 4,820 acre-feet during the 21-year period. EATON CREEK Outflow in Eaton Creek was measured at Station 4117, just below the area boundary, from 1929-30 to 1935-36, inclusive, with exception of the year 1931-32. It has been measured at Station 4116, one-half mile above the boundary, since 1938-39. Discharge for years of missing record during the 11-year period is estimated by comparison with measured flow of Eaton Creek at Stations 2941A and 4090. Resultant average annual outflow in Eaton Creek during the 11-year base period is 1,100 acre-feet. Rainfall on valley area and inflow from mountains both averaged greater during the 29- and 21-3^ear periods than during the base period. Sufficient records are not yet available to determine accurately the effect of Eaton Wash Reservoir on outflow, but percolation has been increased, and it is therefore estimated that both 29- and 21-year outflow in Eaton Creek averages the same as during the 11-year period, 1,100 acre-feet annually. SOUTH COASTAL BASIN INVESTIGATION 103 BROADWAY, GRANADA AND RUBIO DRAINS Outflow in Broadway Drain has been measured at Stations 4057 or 4068 for all except a few months since 1923-24. That in Granada Drain has been measured at Station 4057A since 1935-36, and for Rubio Drain records of outflow at Station 4108 are available for all except a few months from 1923-24 to date. Discharges in each of these drains during missing or incomplete years of the ll-j^ear period are estimated by com- parison with flow in Seco Drain. Total average outflow in the three is estimated at 2,810 acre-feet annually during the 11-year base period. For the 29- and 21-3^ear periods, outflow during years of missing record is estimated from its relationship with precipitation at valley stations of the Raymond Basin Group. Total average annual outflow in the drains during the 29-3^ear period is thus estimated at 2,660 acre-feet, and that during the 21-year period at 2,810 acre-feet. UNMEASURED OUTFLOW It is estimated that unmeasured outflow from those portions of the area not draining into the above channels includes 25 percent of the inflow from tributary mountains, all of that from hills, and a portion of the precipitation on valley land ranging from 9 percent of that on a small area tributary to Verdugo Creek, to 17 percent of that in the southerly part of the City of Pasadena. TABLE 29. SURFACE OUTFLOW FROM WESTERN UNIT OF RAYMOND BASIN AREA Average annual for 29-year period, 1904-0 5 to 193 2-3 3, inclusive; 21 -year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-3 8, inclusive (Acre-feet) 29-year 21-year 11-year period period period To Verdugo Basin Estimated, originating in : Directly tributary mountains and hills 90 Precipitation on valley land 130 Subtotal 220 To Los Angeles Narrows Basin Measured during part of period 6,180 To Central San Gabriel Valley Area Measured during part of period 3,760 Estimated, originating in Directly tributary mountains 190 Precipitation on valley land 1,230 70 140 70 180 210 200 4,820 2,620 3,910 3,910 160 1,260 150 1,210 Subtotal 5,180 5,330 5,270 Total 11,580 10,360 8,090 104 DIVISION OF WATER RESOURCES Subsurface Outflotv Assuming- that all items involved have been correctly evaluated, sub- surface outflow during the 11 -year base period must, in accordance with principles set forth in Chapter V, have averaged 2,860 acre-feet annually, as derived in Table 30. TABLE 30. ESTIMATED AVERAGE ANNUAL SUBSURFACE OUTFLOW FROM WESTERN UNIT OF RAYMOND BASIN AREA DURING THE 11 -YEAR PERIOD, 1927-28 TO 1937-3 8, INCLUSIVE Acre-feet Water entering area Precipitation 40,810 Surface inflow 11,650 Import 3,480 • Decrease in storage in area 5,810 Subtotal 61,750 Water leaving area on surface Surface outflow 8,090 Exported water 9,500 Exported sewage 5,130 Consumptive use 36,170 Subtotal 58,890 Subsurface Outflow — to Central San Gabriel Valley Area 2,860 Required Long-time Mean Import Under "Present Conditions The hydrologic equation used in the preceding article applies equally vrell for any period. Since extractions are now limited to safe yield, there can be neither excess nor overdraft, and net change in storage over a cycle of long-time mean supply must be zero. Assuming that subsurface outflow is the same in all periods, items involved in the equation, other than required import, have been evaluated for both 29- and 21-year cycles. If the 21-year period is assumed to represent the cycle of long-time mean supply, required long-time mean annual import is 5,910 acre-feet, as derived in Table 31. If the 29-year period is so considered, the derived value is 5,540 acre-feet. These values are predicated on the assumption that a large part of the runoff in Arroyo Seco is conserved by spreading. It is estimated that an annual average of 960 acre-feet can be so conserved over the 21-year period. If this is not done, required import will be correspondingly greater. As sewer systems, now authorized, are installed for presently unsew- ered areas in County Sanitation Districts Nos. 15 and 17, required import will be further increased by the amount of any additional sewage outflow. SOUTH COASTAL BASIN INVESTIGATION 105 TABLE 31. ESTIMATED REQUIRED AVERAGE ANNUAL IMPORT TO WESTERN UNIT OF RAYMOND BASIN AREA UNDER PRESENT CONDITIONS ASSUM- ING THE 21 -YEAR PERIOD, 1922-2 3 TO 1942-43, INCLUSIVE, TO BE A CYCLE OF LONG-TIME MEAN SUPPLY Demand on area ' Acre-feet Consumptive use 86,170 Exported water 4,620 Exported sewage 7,280 Surface outflow 10,360 Subsurface outflow 2,860 Subtotal 61,290 Supply to area exclusive of import Precipitation — 42,210 Surface inflow 13,170 Subtotal 55,380 Required Import 5,910 EASTERN UNIT OF RAYMOND BASIN AREA Santa Anita Sub-area (8b) Santa Anita Sub-area of Kaymoncl Basin is located in the north- westerlj^ portion of San Gabriel Valley, and covers about 3.6 square miles. It is bounded on the west by Pasadena Sub-area, on the northeast and east by San Gabriel Mountains, and on the south and southeast by Raymond Fault, beyond which lies Main San Gabriel Basin. Topography is quite regular throughout, with slopes from loO to 600 feet per mile, increasing toward the mountains. Elevations above sea level range from 525 to about 1,400 feet. Soils covering this area are mostly lighter members of the Hanford series, with scattered areas of Ramona and Placentia soils, and some of the heavier Chino soils just above Raymond Fault. Municipal development occupies about 32 percent of the area, about 22 percent is devoted to agriculture, and the remainder is in a more or less natural state. The local water supply, utilized to some extent through diversion from surface streams, but more through pumping from ground water, originates in precipitation on the valley, and inflow from 10,510 acres of mountains directly tributary to the area. There is no import of water or sewage. A considerable part of the surface inflow and precipitation flows out into Main San Gabriel Basin together with some underflow, and water is exported in relatively large amount to Main San Gabriel Basin and the Western Unit of Raymond Basin Area. Water rights in the Eastern Unit of Raymond Basin Area have recently been adjudicated,* and extractions are now limited to safe yield of the basin. The court retains jurisdiction so that future adjustments in rights may be made when necessary due to changed conditions. Water- master service by the Division of Water Resources started on July 1, 1944. Under the above conditions there can be no overdraft. Present demand for use within the area is somewhat less than available supply, * Case No. Pasadena C-1323, Superior Court, Los Angeles County, December 23, 1944. 106 DIVISION OF VrATER RESOURCES and the excess is exported. Such adjiistment as is necessary to make demand equal safe yield must be made in the amount exported. There- fore, long-time mean permissible export under present conditions is deriA^ed herein. Evaluation of items required* to estimate its amount, follows. Inflotv Estimated annual surface inflow to the unit averages 7,410 acre- feet, 6,410 acre-feet and 5,780 acre-feet annually in the 29-, 21- and 11-year periods, respectii^ely, as derived in Table 32. Annual inflow from directly tributary mountain area, above gaging stations at which runoff has been measured during a part of each period, is tabulated below. Twenty-nine year mean annual values are derived by comparison with San Gabriel River. Mean annual infloio in acre-feet 9,i)-iip.nr 9,1-iip.n.r 11-iienr 29-year 21-year 11-year Stream Station period period period Little Santa Anita 4151A 810 700 600 Big Santa Anita__ 4180 5,270 4,610 4,140 Total 6,080 5,310 4,740 The estimate of 29-year mean annual inflow from 3,300 acres of mountains directly tributary to the unit, and downstream from gaging stations at which above infloAV was measured, is based on the assump- tion that, if water is available, average consumptive use on mountain area is 22 inches, inflow however being never less than seven percent of precipitation on the mountains. The 11-year value is estimated to be 0.78 times the 29-year mean, this being the ratio between 11- and 29-year mean discharge of San Gabriel River. The corresponding ratio for the 21-year period is 0.83. Subsurface inflow, other than that indicated by note in Table 32, is negligible. TABLE 3 2. SURFACE INFLOW TO EASTERN UNIT OF RAYMOND BASIN* AREA Average annual for 29-year period, 1904-0 5 to 193 2-3 3, inclusive; 21 -year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38 inclusive (Acre-feet) 29-year 21-year 11-year period period period From directly tributary mountains Measured during part of period'' 6,080 5,310 4,740 Estimated'^ 1,330 , 1,100 . 1,040 Total 7,410 6,410 5,780 * Evaporation loss in Big Santa Anita Reservoir is considered negligible and values given are not corrected for this loss. *> Includes a relatively small amount of underflow. * Values of change in storage and precipitation, also required, are presented in Tables 5 and 7. SOUTH COASTAL BASIN INVESTIGATION 107 Consuifiptive Use In Table 33 an estimate of consumptive use based on a detailed culture survey conducted by the City of Pasadena in 1935, 1938 and 1939 is presented. Unit values are estimated largely from soil moisture tests. Municipal development includes the City of Sierra Madre and a portion of the City of Arcadia. Industrial development is negligible. Natural vegetation growing on unused land ranges from heavy brush in the northwesterly portion of the basin, to light brush, weeds and grass elsewhere, with scattered trees in the southerly portion. Change in consumptive use due to cultural development has been small enough so that the values derived in Table 33 are considered average for present conditions as well as for the 11 -year period. TABLE 3 3. ESTIMATED AVERAGE ANNUAL CONSUMPTIVE USE IN EASTERN UNIT OF RAYMOND BASIN AREA Cultural classification Unit consumptive use, feet Acres Acre-feet Estates 2.07 Class A residential 1.92 Class B residential 1.88 Rural residential 1.78 Commercial — 0.50 Semicommercial 1.32 Reservoir sites 1.34 Schools — 1.63 Vacant 1.50 Ornamental trees 1.58 Avocado and citrus 2.00 Deciduous 1.75 Vineyard 1.67 Brush 1.67 Truck and nursery 3.00 Riverwash 0.99 Streets 0.50 Total 217 4-10 79 152 90 169 83 148 6 3 2 3 8 11 6 10 313 469 444 701 296 . 592 4 7 5 8 204 340 206 618 101 100 260 130 2,324 3,910 Historical Export In Table 34 estimated values of exports of water, to Main San Gabriel Basin and Western Unit of Kaymond Basin Area, for each year since 1927-28 are presented. There is no sewage outflow. During the 11-year period, an annual average of 2,430 acre-feet of water was exported. TABLE 34. EXPORT FR.OM EASTERN UNIT OF RAYMOND BASIN AREA Year Acre-feet Year Acre-feet Year Acre-feet 1927-28 2.620 1928-29 2,410 1929-30 2,280 1930-31 2,530 1931-32 2,230 1932-33 2,190 1933-34 2,700 1934-35 1,640 1935-36 2,200 1936-37 2,850 1937-38 3,100 1938-39 2,660 1939-40 2,800 1940-41 3,130 1941-42 8,690 1942-43 3,620 1943-44 4,100 1944-45 2,700 108 DIVISION OF WATER RESOURCES Surface Outflotv Outflow on the surface includes part of the inflow from directly tributary mountains and runoff originating in precipitation on valley lands within the unit. It is estimated to average 4,410 acre-feet, 4,180 acre-feet and 3,510 acre-feet in the 29-, 21- and 11-year periods, respec- tively, as derived in Table 35. Most of the inflow from directly tributary mountains is in Big Santa Anita Creek, which for one and one-half miles skirts the mountains bordering the area on the east. In this reach high bed-rock beneath the channel limits percolation. The upper reach of Little Santa Anita Creek below its canyon mouth has been lined since 1928, and lining of the channel throughout its length above its junction with Big Santa Anita Creek was completed in 1940. Spreading grounds on Little Santa Anita compensate to some extent for resultant decrease in natural percolation, althougli no records of amount of water spread are available. Regulation of Big Santa Anita Creek by the flood control reservoir two and one-half miles upstream from Foothill Boulevard has little effect on outflow from the area, because of restricted percolation in the channel above the area boundary. Outflow from the area in Santa Anita Creek has been measured at Stations 4174 and 4174B during the periods 1923-24 to 1926-27, and 1938-39 to date, inclusive. A reasonably close relationship was found to exist between this measured outflow and combined vearlv runoff at the two mountain gaging stations, 4180 and 4151A, on Big and Little Santa Anita Creeks, respectively, at which flow has been measured since 1916-17. Estimates of runoff at these latter two stations for years prior to begin- ning of record were made by comparison with San Gabriel River. Using these measured and estimated values of runoff at upper mountain sta- tions, and the relationship of measured runoff to measured outflow men- tioned above, outflow from the area for years of no record was estimated. It is estimated that outflow from the portion of the area not tributary to the two main streams includes 25 percent of inflow from directly tribu- tary mountains, and 11 percent of precipitation on the valley land. TABLE 3 5. SURFACE OUTFLOW FROM EASTERN UNIT OF RAYMOND BASIN AREA Average annual for 29-year period, 1904-0 5 to 193 2-3 3, inclusive; 21 -year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38 inclusive (Acre-feet) 29-ijear 21-year 11-year period period period Measured during part of period 4,100 3,050 3,290 Estimated, originating in Directly tributary mountains,. 10 10 10 Precipitation on valley land__ 210 220 210 Total 4,410 4,180 3,510 SOUTH COASTAL BASIN INVESTIGATION 109 Subsurface Outflow Assuming that all items involved have been correctly evaluated, subsurface outflow during the 11-year base period, must, in accordance with principles set forth in Chapter V, have averaged 240 acre-feet annually, as derived in Table 36. TABLE 3 6. ESTIMATED AVERAGE ANNUAL SUBSURFACE OUTFLOW FROM EASTERN UNIT OF RAYMOND BASIN AREA DURING THE 11 -YEAR PERIOD, 1927-28 TO 1937-3 8, INCLUSIVE Acre-jeet Water entering area Precipitation 4,310 Surface inflow 5,780 Water coming from storage in area Subtotal 10,090 Water leaving area on surface Surface outflow 3,510 Export 2,430 Consumptive use 3,910 Subtotal 9,850 Subsurface Outflow — to Central San Gabriel Valley Area 240 Long-time Mean Amount Available for Export The hydrologic equation used in the foregoing article applies equally well in any period. Since there is neither excess nor overdraft, net change in storage over a cycle of long-time mean supply is zero. Assuming that subsurface outflow is the same in all periods, all items involved except export have been evaluated for both 29- and 21-year cycles. If the 21-year period is assumed to represent the cycle of long-time mean supply, mean annual export is 2,540 acre-feet, as derived in Table 37. If the 29-year period is so considered, the value is 3,220 acre-feet, derived by substi- tuting 29-year mean values of precipitation, surface inflow, and surface outflow in the table. The value derived for the 21-year period is considered more reliable, since stream flow data for that period are more complete than for the 29-year period. Further, it is the more conservative of the two values. It is therefore estimated that 2,540 acre-feet can be exported annually under present conditions without progressive and permanent change in the water table elevation. As the sewerage improvements now authorized are installed, and sewage is exported to the ocean, allowable export for use will be decreased by the amount of sewage outflow. 110 DIVISION OF WATER RESOURCES TABLE 37. ESTIMATED AVERAGE ANNUAL AMOUNT AVAILABLE FOR EXPORT FROM EASTERN UNIT OF RAYMOND BASIN AREA UNDER PRESENT CONDITIONS ASSUMING THE 21 -YEAR PERIOD, 1922-23 TO 1942-43, INCLUSIVE, TO BE ONE OF LONG-TIME MEAN SUPPLY (Acre-feet) Acre-feet Supply to area Precipitation 4,460 Surface inflow G,410 Subtotal — 10,870 Demand on area, exclusive of export Consumptive use 3,910 Surface outflow ' 4,180 Subsurface outflow 240 Subtotal 8,330 Available for export 2,540 GLENDORA BASIN ( i 1 ) Glendora Basin is located in the northeasterly portion of San Gabriel Valley, and covers about 5.2 square miles. It is bounded on the west by Main San Gabriel and Lower Canj^on Basins, on the north and northeast by San Gabriel Mountains, and on the south by Way Hill Basin and Way Hill. Except for a small area at its eastern extremity topography of this basin is smooth. The southwesterly trending slope down the well marked cone of Big and Little Dalton Creeks varies between 100 and 150 feet per mile. Easterly from hills which border the basin on the south, topography is rolling. Elevations above sea level range from 700 to 1,100 feet. Soils covering this basin are almost entirelv lighter members of the Hanf ord series and are quite absorptive. ]\Iunicipal development occupies about 10 percent of the area, 79 percent is devoted to agriculture, and the remainder is in a more or less natural state. The local water supply, utilized to a minor extent through diversion from surface streams, but more through pumping from ground water, originiates in precipitation on the valley, and inflow from 10,200 acres of mountains and 420 acres of hills directly tributary to the basin. Imported water provides a relatively large addition to the supply. A considerable part of the surface inflow and precipitation flows into Main San Gabriel Basin, together with some underflow. There is no export of water or sewage. In this basin, long-time mean annual net supply under present con- ditions is greater than present annual demand, so an excess exists. Evalua- tion of items required to estimate its amount follows.* htfiow Estimated annual surface inflow to the basin averages 3,100 acre- feet, 2,550 acre-feet and 2,280 acre-feet in the 29-, 21- and 11-year periods, respectively, as derived in Table 38. Annual inflow from directly tributary mountain area, above gaging stations at which the flow was measured during a part of each period, is * Values of change in storage and precipitation, also required, are presented in Tables 5 and 7. SOUTH COASTAL BASIN INVESTIGATION 111 tabulated below. The 29-year value for Big Dalton Creek is derived by comparison with San Gabriel River and San Dimas Creek. Values for Little Dalton Creek for all three periods are derived by comparison with Big Dalton Creek. Annual inflow in acre-feet 29-year 21-year 11-year Stream Station period period period Little Dalton 4364 850 690 610 Big Dalton 4374 1,300* 1,050" 910" Total 2,150 1,740 1,520 « Measured discharge, plus diversions, corrected for change in reservoir storage but not corrected for reservoir losses. *> Actual flow including diversions, uncorrected for reservoir operation. The estimate of 29-year mean annual inflow from 3,410 acres of mountains directly tributary to the basin, and downstream from gaging stations at which above inflow was measured, and from 420 acres of directly tributary hills is based on the assumption that, if water is avail- able, average consumptive use on the mountain area is 20 inches and that on the hill area 17 inches, inflow values, however, being never less than 8 percent of the precipitation on the mountains and 9^ percent of that on the hills. The 11-year value for mountains is estimated to be 0.78 times the 29-3^ear mean, this being the ratio between 11- and 29-year mean discharge of San Gabriel River. That for hills is 0.98 times the 29-year mean, being proportional to precipitation on the area represented by the San Gabriel Valley Group. Corresponding ratios for the 21-year period are 0.83 for mountains and 1.00 for hills.* Subsurface inflow, other than that referred to by note in Table 38, is negligible. TABLE 3 8. SURFACE INFLOW TO GLENDORA BASIN Average annual for 29-year period, 1904-05 to 1932-33, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-3 8 inclusive (Acre-feet) 29-year 21-year 11-year period period period From directly tributary mountains Measured during part of period 2,150 1,740 1,520 Estimated « 850 710 660 From directly tributary hills Estimated'' 100 " 100 100 Total 3,100 2,550 2,280 * Includes a relatively small amount of underflow. Import In Table 39 estimated values of imports of water for each year since 1927-28 are presented. There is no import of sewage. During the 11-year period, an annual average of 2,910 acre-feet of water was imported from pumped sources in Main San Gabriel and San Dimas Basins. * If inflow from hills is assumed to follow the same regimen of flow as San Gabriel River, 21- and 11-year average values each equal 80 acre-feet. 112 DIVISION OF WATER RESOURCES The amount of water imported depends to some extent upon the amount of gravity water available from Big Dalton and Little Dalton Creeks. It is therefore estimated that average annual import under present conditions is 2,760 acre-feet, equal to the average import for the four-year period 1941-42 to 1944-45 inclusive, plus the difference between four year and 21-year average gravity diversions from Big and Little Dalton Creeks. TABLE 39. IMPORT TO GLENDORA BASIN Year Acre-feet Year Acre-feet Year Acre-feet 1927-28 2,380 1933-34 3,790 1939-40 2,220 1928-29 2,530 1934-35 1,960 1940-41 1,220 1929-30 3,290 1935-36 3,080 1941-42 2.640 1930-31 3.720 1936-37 1,800 1942-43 J__ 2,260 1931-32 3,380 1937-38 2.030 1943-44 2,630 1932-33 4,000 1938-39 2,660 1944-45 2,370 Consumptive Use In Table 40 estimates of consumptive use based on culture surveys conducted by the Division of ^Yater Resources in 1932 and 1942 are presented. LTnit consumptive use is discussed in Chapter V. In the City of Glendora, which lies entirely within the basin, industrial development is small. Natural vegetation growing on the little unused land is mostly moderately heavy brush. • TABLE 40. ESTIMATED AVERAGE ANNUAL CONSUMPTIVE USE IN GLENDOR^ BASIN Unit con- sumptive 1932 1942 Type of culture use, feet Acres Acre-feet Acres Acre-feet Valley Area Garden and field 1.3 6 Avocado and citrus 1.9 2,586 Deciduous 1.7 69 Domestic and industrial 1.5 291 Unirrigated 369 29- and 21-year periods 1.4 11-year period 1.385 Subtotal 3,321 3,321 29- and 21-year periods 5,987 11-year period 5,985 Hill and Mountain Area Avocado and citrus 0.5" 237 118 237 118 8 6 8 4,913 2,597 4,934 117 22 37 436 338 507 358 ^^__ 501 511 Grand total 3,558 3,558 29- and 21-year periods 6,105 11-year period 6,103 Difference between irrigated culture and natural vegetation. SOUTH COASTAL BASIN INVESTIGATION 113 Surface Outflow Outflow on the surface includes part of the inflow from directly tributary mountains and hills, and runoff originating in precipitation on the overlying valley. It is estimated to average 1,320 acre-feet, 1,130 acre-feet and 1,190 acre-feet annually in the 29-, 21- and 11-year periods, respectively, as derived in Table 41. A large part of the mountain water entering this basin is concen- trated in Big and Little Dalton Creeks. Some regulation is secured in Big Dalton Reservoir, and spreading is resorted to on both streams. Below spreading grounds both streams flow approximately two and one-half miles across the basin. The channels of both are restricted as to width, and that of Little Dalton Creek is paved for about two-thirds of a mile through the City of Glendora. Some mountain inflow from directly north of the city is carried to the channel along paved streets. Other small intermittent streams from the mountains, between the city and Little Dalton Canyon, flow for considerable distances across the alluvium before entering the channel. Big Dalton Creek skirts the mountains to the east and the hills to the south, and is unpaved throughout. Daily discharges of Big Dalton Creek at Station 4374, and of Little Dalton Creek at Stations 4363 and 4364, have been measured for the periods 1920-21 to date, and 1929-30 to date, respectively. Assuming that 15 second-feet is diverted to spreading from Big Dalton during all three periods, 10 second-feet from Little Dalton under present conditions and five second-feet during the 11-year period, and that, with respective discharges of five second-feet and two second-feet in Big and Little Dalton Creeks below spreading grounds, no water reaches the lower boundary of the basin, outflow of water from this source during each year of record is estimated, utilizing percolation curves. Using the rela- tionship between this outflow and measured annual discharges at the gaging station, average annual outflow in the two streams, from water originating above the gaging stations during the 29- and 21-year periods, is estimated. It is further estimated that outflow originating below these gaging stations comprises 50 percent of inflow from directly tributary mountains and hills, and 7 percent of precipitation on valley area within the basin. TABLE 41. SURFACE OUTFLOW FROM GLENDORA BASIN Average annual for 29-year period, 1904-05 to 1932-33, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-3 8 inclusive (Acre-feet) Estimated, originating in Measured mountain streams Other directly tributary mountains Directly tributary hills Precipitation on valley land Total 1,320 1,130 1,190 8—71061 29-year 21-year 11-year period period period 430 320 410 430 350 330 50 50 50 410 410 400 114 DIVISION OF WATER RESOURCES Excess Assuming that the 21-year period is the cycle of long-time mean supply, estimated annual excess is 560 acre-feet, as derived in Table 42. If 29-year mean values are substituted in the table, the derived annual excess is 920 acre-feet. TABLE 42. ESTIMATED ANNUAL EXCESS IN GLENDORA BASIN UNDER PRESENT CONDITIONS ASSUMING THE 21 -YEAR PERIOD, 1922-23 TO 1942-43, INCLUSIVE, TO BE ONE OF LONG-TIME MEAN SUPPLY (Acre-feet) Estimated Actual long-time 11-year mean annual base under period present average Differ- conditions annual ence Average annual rise in storage during base period 250 Items tending to increase the rise Precipitation 5,900 5,770 130 Surface inflow 2,550 2,280 270 Import 2,760 2,910 —150 Subtotal to be added 250 Items tending to decrease the rise Consumptive use 6,100 O.KX) Surface outflow 1,130 1,190 —60 Subtotal to be subtracted — — 60 Excess 560 Subsurface Outflow Assuming that all items involved have been correctly evaluated, sub- surface outflow during the 11-year base period, must, in accordance with principles set forth in Chapter V, have averaged 3,420 acre-feet annually, as derived in Table 43. TABLE 43. ESTIMATED AVERAGE ANNUAL SUBSURFACE OUTFLOW FROM GLENDORA BASIN DURING THE 11-YEAR PERIOD, 1927-28 TO 1937-38, INCLUSIVE Acre- feet Water entering basin Precipitation 5,770 Surface inflow 2,280 Import 2,010 Subtotal 10,960 Increase in storage 250 Water leaving basin on surface Surface outflow 1,100 Consumptive use 6,100 Subtotal 7,540 Subsurface Outflow — to Central San Gabriel Valley Area 3,420 SOUTH COASTAL BASIN INVESTIGATION 115 WAY HILL BASIN (12) Way Hill Basin is located in the northeasterly portion of San Gabriel Valley, and covers about 2.6 square miles. It is bounded on the west by Main San Gabriel Basin, on the north by Glendora Basin and Way Hill, and on the east and south by San Dimas Basin. Topography of virtually all of this basin is smooth, v^ith uniform slope to the west at a little less than 100 feet per mile. Elevations above sea level in the vallej^ range from 700 to 1,100 feet. Soils covering this basin are mostly lighter mem- bers of the Hanford series. Municipal development occupies about 13 percent of the area, about 65 percent is devoted to agriculture, and the remainder is in a more or less natural state. The local water supply, utilized to a minor extent through diver- sion from surface streams, but more through pumping from ground water, originates in precipitation on the valley, inflow from 590 acres of mountains and 360 acres of hills directly tributary to the basin, and inflow on the surface from Foothill Basin, the greater part of the last named as flood flow in San Dimas Creek. Imported water provides a relatively large addition to the supply. A considerable part of the surface inflow and precipitation flows out into Main San Gabriel Basin, together with some underflow, and water is exported in relatively small amount to Main San Gabriel and San Dimas Basins. In this basin, long-time mean annual net supply under present conditions is greater than present annual demand, so an excess exists. Evaluation of items required * to estimate its amount, follows. Inflow Estimated annual surface inflow to the basin averages 780 acre-feet, 610 acre-feet and 400 acre-feet in the 29-, 21- and 11-year periods, respectively, as derived in Table 44. The estimate of 29-year mean annual inflow from 590 acres of moun- tains and 360 acres of hills directly tributary to the basin is based on the assumption that, if water is available, average consumptive Ase on mountain area is 19 inches and that on hill area 17 inches, inflow values however being never less than 8^ percent of precipitation on mountains and 9^ percent of that on hills. The 11-year value for mountains is esti- mated to be 0.78 times the 29-year mean, this being the ratio between 11- and 29-year mean discharge of San Gabriel River. That for hills is 0.98 times the 29-year mean, being proportional to precipitation on the area represented by the San Gabriel Valley Group. Corresponding ratios for the 21-year period are 0.83 for mountains and 1.00 for hills, t A part of the surface outflow from Foothill Basin, that in San Dimas Creek, enters Way Hill Basin. Subsurface inflow, other than that indicated by note in Table 44, is negligible. * Values of change in storage and precipitation, also required, are presented in Tables 5 and 7. t If runoff from hills is assumed to follow the same regimen as flow in San Gabriel River, average runoff from that source during the 21-year period is 60 acre-feet, and during the 11-year period 50 acre-feet. 116 DIVISION OF WATER RESOURCES TABLE 44. SURFACE INFLOW TO WAY HILL BASIN Average annual for 29-year period, 1904-05 to 1932-33, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-3 8 inclusive (Acre-feet) 29-year 21-year 11-year period period period From directly tributary mountains Estimated^ From directly tributary hills Estimated" From other basins Foothill Total ■ Includes a relatively small amount of underflow. Import 120 100 70 440 100 70 70 590 230 780 610 400 In Table 45 estimated values of imports of water for each year since 1927-28 are presented. There is no import of sewage. During the 11-year period, an annual average of 1,200 acre-feet was imported from Main San Gabriel, Glendora and San Dimas Basins. Estimated average annual import of water under present conditions is 1,540 acre-feet, equal to the average for the four-year period, 1941-42 to 1944-45, inclusive. TABLE 45. IMPORT TO WAY KILL BASIN Year Acre-feet Year Acre-feet Year Acre-feet 1927-28 740 1933-34 1,470 1939,40 1.180 1928-29 940 1934-35 980 1940-41 1,120 1929-30 1,300 1935-36 1,210 1941-42 1,400 1930-31 1,380 1936-37 1,280 1942-43 1,600 1931-32^ 1,240 1937-38 1,440 1943-44 1,640 1932-33 1,210 1938-39 1,360 1944-45 1,520 Consumptive Use In Table 46 estimates of consumptive use based on culture surveys conducted by the Division of Water Resources in 1932 and 1942 are presented. Unit consumptive use is discussed in Chapter V. Domestic development is scattered over the basin, and industrial development is negligible. Natural vegetation, growing on the relatively little remain- ing unused land, is largely light brush, weeds and grass. SOUTH COASTAL BASIN INVESTIGATION 117 TABLE 46. ESTIMATED AVERAGE ANNUAL CONSUMPTIVE USE IN WAY HILL BASIN Type of culture Unit con- sumptive 1932 m 2 use, feet Acres Acre-feet Acres Acre-feet 1.3 13 17 31 40 1.9 1,026 1,949 1,059 2,012 1.7 5 8 5 8 3.0 10 30 1.5 161 242 223 334 468 365 1.3 ^ ,. ,_ 474 1.286 602 Valley area Garden and field Avocado and citrus Deciduous Irrigated grass Domestic and industrial Unirrigated 29- and 21-year periods 11-year period Subtotal 29- and 21-year periods. 11-year period Hill and Mountain area Avocado and citrus Grand total 29- and 21-year periods 11-year period 0.5' 1,683 52 1,735 2,848 1,683 26 52 2,874 1,735 » Difference between irrigated culture and natural vegetation. Export 2,868 26 2,894 In Table 47 estimated exports of water to Main San Gabriel and San Dimas Basins for each year since 1927-28 are presented. There is no sewage outflow. During the 11-year period an annual average of 140 acre- feet of water was exported. Estimated average annual export under present conditions is 230 acre-feet, equal to the average for the four-year period, 1941-42 to 1944-45, inclusive. TABLE 47. EXPORT FROM WAY HILL BASIN Year Acre-feet Year Acre-feet Year Acre-feet 1927-28 120 1928-29 110 1929-30 160 1930-31 150 1931-32 140 1932-33 170 1933-34 100 1934.35 120 193.5-36 ICO 1936-37 140 1937-38 140 1938-39 170 1939-40 170 1940-41 170 1941-42 150 1942-43 230 1943-44 220 1944-45 300 Surface Outflow Outflow on the surface includes part of the inflow from directly tributary mountains and hills, part of that from Foothill Basin, and runoff originating in precipitation on the overlying valley. Inflow from directly tributary mountains enters the valley at con- siderable distance from the point of outflow, and it is estimated that none reaches that point. Inflow from hills enters the vallc}- nearer the point of outflow, and it is estimated that 75 percent of this, or an annual average 118 DIVISION OF WATER RESOURCES of 50 acre-feet, flows out in all three periods. Inflow from Foothill Basin is largely regulated by operation of San Dimas Reservoir and Pudding- stone Diversion, and estimated average annual outflow originating in that source is 60, 40 and 20 acre-feet for the 29-, 21- and 11-year periods, respectively. On the assumption that 5 percent of precipitation on the valley runs off, annual outflow from that source averages 140 acre-feet. Estimated total m.ean annual surface outflow is 250, 230 and 210 acre-feet in the 29-, 21- and 11-year periods, respectively. Excess Assuming that the 21-year period is the cycle of long-time mean supply, estimated annual excess is 710 acre-feet, as derived in Table 48. If 29-year mean values are substituted in the table, the derived annual excess is 860 acre-feet. TABLE 48. ESTIMATED ANNUAL EXCESS IN WAY HILL BASIN UNDER PRESENT CONDITIONS ASSUMING THE 21 -YEAR PERIOD, 1922-23 TO 1942-43, INCLUSIVE, TO BE ONE OF LONG-TIME MEAN SUPPLY (Acre-feet) Estimated Actual long-time 11-year t mean annual base under period present average Differ conditions annual ence Average annual rise in storage during base period Items tending to increase the rise Precipitation 2,800 2,730 70 Surface inflow 610 400 210 Import 1,540 1,200 340 Subtotal to be added Items tending to decrease the rise Consumptive use 2,890 2,870 20 Surface outflow 230 210 20 Export 230 140 90 Subtotal to be subtracted Excess 220 620 130 710 Subsurface Outflotv Assuming that all items involved have been correctly evaluated, subsurface outflow during the 11-year base period, must, in accordance with principles set forth in Chapter V, have average 890 acre-feet annually, as derived in Table 49. SOUTH COASTAL BASIN INVESTIGATION 119 TABLE 49. ESTIMATED AVERAGE ANNUAL SUBSURFACE OUTFLOW FROM WAY HILL BASIN DURING THE 11-YEAR PERIOD, 1927-28 TO 1937-38, INCLUSIVE Acre-feet Water onterinij basin Precipitation 2,730 Surface inflow 400 Import 1,200 Subtotal 4,330 Increase in storaire 220 Water leaving basin on surface Surface outflow 210 Export 140 Consumptive use 2,870 Subtotal 3,440 Subsurface Outflow — To Central San Gabriel Valley Area 890 FOOTHILL BASIN (14) Foothill Basin is located at the mouth of San Dimas Canj^on in the extreme northeasterly corner of San Gabriel Vallev, and covers about 1.9 square miles. It is bounded on the northwest, north and east by San Gabriel Mountains, and on the south by San Dimas Basin. Topography is irregular with slopes varying in direction from southwest to southeast, at rates ranging between 100 and 500 or more feet per mile. Elevations above sea level range between 1,100 and 1,800 feet. Soils are about half Ramona loam, and half Hanford and Yolo soils. There is no municipal development, about 42 percent of the area being devoted to agriculture, with 58 percent remaining in a more or less natural state. The local water supply, utilized in part through diversion from San Dimas Creek, partially regulated in San Dimas Reservoir, and in part through pumping from ground water, originates in precipitation on the valley and inflow from 14,090 acres of mountains directly tributary to the basin. Imported water provides a relatively small addition to the supply. A considerable part of the surface inflow and precipitation flows out into Wav Hill and San Dimas Basins, tosrether with some underflow into the latter, and water is exported in relatively large amount to San Dimas Basin. In this basin long-time mean annual supply under present condi- tions is greater than present annual demand, but storage capacity through which this supply can be utilized is so limited that it is logical to assume that all excess flows out. Evaluation of items required to estimate the long-time mean amount of surface outflow follows.* Inflow Estimated annual surface inflow to the basin averages 4,420 acre- feet, 3,660 acre-feet and 3,190 acre-feet in the 29-, 21- and 11-year periods, respectively, as derived in Table 50. * Values of change In storage and precipitation, also required, are presented in Tables 5 and 7. 120 DIVISION OF WATER RESOURCES Flow in San Dimas Creek at Station 4425, was measured throughout the 11- and 21-year periods, and during a part of the 29-year period. The 29-3'ear value is derived by comparison with San Gabriel River. The estimates of 29-year mean annual inflow from the 2,430 acres of mountains dii*ectly tributarj^ to the basin, and downstream from the gaging station at which above inflow was measured, is based on the assumption that, if water is available, average annual consumptive use is 21 inches, runoff however never being less than 7J percent of precipi- tation. The 11-vear value is estimated to be 0.78 times the 29-vear mean, this being the ratio between 11- and 29-year mean discharge of San Gabriel River. The corresponding ratio for the 21-year period is 0.83. Subsurface inflow, other than that indicated by note in Table 50, is negligible. TABLE 50. SURFACE INFLOW TO FOOTHILL BASIN Average annual for 29-year period, 1904-05 to 1932-33, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38 inclusive (Acre-feet) 29-year 21-year 11-year period period period From directly tributary mountains Measured during part of period 4,080 * 3,380 » 2,930 " Estimated «= 340 280 260 Total 4,420 3,660 3,190 * Based on measured discharge, corrected for change in storage in reservoir but not corrected for reservoir losses. ^ Based on actual discharge, uncorrected for reservoir operation. •^ Includes a relatively small amount of underflow. Import In Table 51 estimated values of imports of water for each year since 1927-28 are presented. There is no import of sewage. During the 11-year period an annual average of 120 acre-feet of water was imported from pumped sources in San Dimas Basin. Estimated average annual import under present conditions is 160 acre-feet, equal to the average for the four-year period, 1941-42 to 1944-45, inclusive. TABLE 51. IMPORT TO FOOTHILL BASIN Year Acre-feet Year Acre-feet Year Acre-feet 1927-28 1928-29 1929-30 1930-31 1931-32 1932-33 Consumptive Use In Table 52 estimates of consumptive use based on culture surveys conducted by the Division of Water Resources in 1932 and 1942 are presented. Unit consumptive use is discussed in Chapter V. There is no 100 1933-34 130 1939-40__ 120 140 1934-35 120 1940-41 120 100 1935-36 120 1941-42 150 110 1936-37 130 1942-43 160 140 1937-38 130 1943-44 140 150 1938-39 120 1944-45 170 SOUTH COASTAL BASIN INVESTIGATION 121 industrial and very little domestic development. Unused land is largely of irregular topography, or is subject to overflow by San Dimas Creek and is covered by brush of varying size and density. TABLE 5 2. Type of culture ESTIMATED AVERAGE ANNUAL CONSUMPTIVE USE IN FOOTHILL BASIN Unit con- sumptive 1932 19/f2 use, feet Acres Acre-feet Acres Acre-feet Valley area Avocado and citrus Deciduous Unirrigated 29- and 21-year periods. 11-year period Subtotal 1.9 469 891 519 986 1.7 7 12 757 714 1.4 ^___ , _^ 1,000 1.385 1,048 — 1,233 1,233 29- and 21-year periods. 11-year period Mountain area Avocado and citrus. 0.5 59 Grand total 29- and 21-year periods. 11-year period 1,292 1,951 30 1,981 59 1,292 1,986 30 2,016 * Difference between irrigated culture and natural vegetation. Export In Table 53 estimated exports of water for each year since 1927-28 are presented. There is no sewage outflow. During the 11-year period, an annual average of 560 acre-feet of water was exported to San Dimas Basin from gravity sources in San Dimas Canyon. The amount of water exported depends upon the amount of gravity water available. It is estimated that long-time mean annual export under present conditions is 670 acre-feet, equal to the average for the 21-year period, for each year of which records are available. TABLE 5 3. EXPORT FROM FOOTHILL BASIN Yeai Acre- feet Year Acre-feet Year Acre- feet 1927-28. 1928-29. 1929-30. 1930-31. 1931-32. 1932-33. 150 1933-34 340 1934-35 380 1935-36 230 1936-37 350 1937-38 210 1938-39 180 1939-40 800 1940-41 460 1941-42 1,210 1942-43 1,870 1943-44 610 1944-45 690 1,290 780 1,600 1,910 1,570 Surface Outflow During 11 -Year Period Outflow on the surface includes part of the inflow from directly tributary mountains, and runoff originating in precipitation on the over- lying valley. It is estimated to average 1,820 acre-feet annually during the 11-year period, as derived in Table 54. 122 DIVISION OF WATER RESOURCES The greater part of outflow, that in San Dimas Creek, has been measured at Pudclingstone Diversion Dam since 1935-36. Discharge at Station 4425 has been measured since 1917-18, and diversions just below, that station since 1913-14. From the relationship between discharge at Puddingstone Diversion Dam, and the difference between discharge and diversion at the upper station, established during years of record common to all, discharge at the lower station during the years between 1927-28 and the beginning of record there is estimated. To estimate outflow from areas not tributary to Puddingstone Diver- sion Dam, it is assumed that 80 percent of inflow from mountains east of the creek, 50 percent of that from those to the west, and 6 percent of precipitation on valley land east of the creek flows out on the surface. TABLE 54. AVERAGE ANNUAL SURFACE OUTFLOW FROM FOOTHILL BASIN DURING THE 11-YEAR PERIOD, 1927-28 TO 1937-3 8, INCLUSIVE (Acre-feet) Estimated, originating in San Dimas Creek and Puddingstone Diversion 1,550 Directly tril)utary mountains 180 Precipitation on valley land 90 Total 1,820 Subsurface Outflotv Assuming that all items involved have been correctly evaluated, subsurface outflow during the 11-year base period, must, in accordance with principles set forth in Chapter V, have averaged 1,080 acre-feet annually, as derived in Table 55. TABLE 5 5. ESTIMATED AVERAGE ANNUAL SUBSURFACE OUTFLOW FROM FOOTHILL BASIN DURING THE 11-YEAR PERIOD, 1927-28 TO 1937-38, INCLUSIVE Acre-ieet "Water entering basin Precipitation 2,130 Surface inflow 3,190 Import 120 Change in storage in basin Subtotal 5,440 Water leaving basin on surface Surface outflow 1,820 Export 560 Consumptive use 1,980 Subtotal 4,360 Subsurface Outflow — to San Dimas Basin 1,080 Long-time Mean Surface Outflotv The hydrologic equation used in the preceding article applies equally well in any period. Since there is neither excess nor overdraft in Foothill Basin, net change in storage over a cycle of long-time mean supply is zero. SOUTH COASTAL BASIN IN\rESTIGATION 123 Assuming that subsurface outflow is the same in all periods, all items involved other than surface outflow have been evaluated for both 29- and 21-year cycles. If the 21 -year period is assumed to represent the cycle of long-time mean supply, long-time mean annual surface outflow is 2,230 acre-feet, as derived in Table 56. If the 29-year period is so considered, the value is 2,990 acre-feet. TABLE 5 6. ESTIMATED LONG-TIME MEAN ANNUAL SURFACE OUTFLOW FROM FOOTHILL BASIN ASSUMING THE 21 -YEAR PERIOD, 1922-23 TO 1942-43, INCLUSIVE, TO BE ONE OF LONG-TIME MEAN SUPPLY Acre- feet Supply to basin Precipitation 2,180 Surface inflow 3,660 Import 160 Subtotal 6,000 Demand on basin other than surface outflow Consumptive use 2,020 Export 670 Subsurface outflow 1,080 Subtotal 3,770 Surface Outflow 2,230 SAN DIMAS BASIN (13) San Dimas Basin is located in the easterly portion of San Gabriel Valley, and covers about 7.4 square miles. It is bounded on the west by Main San Gabriel Basin, on the north by Way Hill and Foothill Basins, on the northeast by San Gabriel ]\Iountains, and on the southeast by Live Oak Basin and San Jose Hills. Topography of a large part of this basin is irregular because of several deeply incised barrancas which cut across it. Slope is generally to the southwest, and over most of the area averages a little less than 100 feet per mile. Lateral slopes in arroyos are much steeper. Elevations above sea level range from 650 to 1,225 feet. Soils covering the northerly half of this basin are lighter members of the Ilanford series, and are quite receptive of moisture. Ramona loam, a little less pervious, covers the lower, southerly half. About 6 percent of the area is covered by culture of a municipal type, about 89 percent is devoted to agriculture, and only about 5 percent is still in a more or less natural state. The local water supply, utilized to a minor extent through diver- sion from surface streams, but more through pumping from ground water, originates in precipitation on the valley, inflow from 110 acres of moun- tains and 4,290 acres of hills directly tributary to the basin, inflow on the surface from Foothill and Pomona Basins, and inflow underground from Foothill Basin, the greater part of the surface inflow being in Pudding-stone Diversion from San Dimas Creek. Imported water provides a relatively large addition to the supply. A considerable part of the precipitation flows out into Main San Gabriel Basin together with some underflow. Most of the surface inflow is stored in Puddingstone Reservoir. A relativelj^ large amount is exported 124 DR^SION OF WATER RESOURCES to AYav Hill and Foothill Basins, and a lesser amount to Pomona and Glendora Basins. In this basin, long-time mean annual net supply under present con- ditions is somewhat greater than present annual demand, so a slight excess exists. Evaluation of items required* to estimate its amount follows. In^oxv Estimated annual surface inflow to the basin averages 3,620 acre- feet, 3,000 acre-feet and 2,780 acre-feet in the 29-, 21- and 11-year periods, respectively, as derived in Table 57. The estimate of 29-year mean annual inflow from 110 acres of moun- tains directly tributary to the basin is based on the assumption that average annual consumptive use on mountain area is 18 inches. Inflow from 4,140 acres of hill area is estimated to be 10 percent of precipitation on the hills. Average inflow from mountains during the 11-year base period is estimated to be 0.78 times the 29-year mean, this being the ratio between 11- and 29-year mean discharge of San Gabriel River. The cor- responding ratio for the 21-year period is 0.83. t Inflow on the surface from other basins includes a part of surface outflow from Foothill and Pomona Basins. Subsurface inflow from Foot- hill Basin averaa'es 1,080 acre-feet annuallv. TABLE 5 7. SURFACE INFLOW TO SAN DLMAS BASIN Average annual for 29-year period, 1904-05 to 1932-33, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38 inclusive {Acre-jeet) 29-year 21-year 11-year period period period From directly tributary mountains Estimated^ 20 From directly tributary hills Estimated* 620 Rainfall on Puddingstone Reservoir Estimated 230 From other basins Pomona 360'^ Foothill 2,390 20 20 620 610 230 230 350 1,780 320 1,600 Total 3,620 3,000 2,780 • Includes a relatively small amount of underflow. ^ Mean annual inflow during 32-year period, 1904-05 to 1935-36, inclusive. Import In Table 58 estimated values of imports of water for each year since 1927-28 are presented. There is no import of sewage. Water is imported from Main San Gabriel. Foothill, Pomona, AVay Hill, and Live Oak Basins, and from Colorado River, and is derived from both gravity and pumped sources. During the 11-year period an annual average of 3,500 acre-feet was imported. * Values of change in storage and precipitation, also required, are presented in Tables 5 and 7. t If inflow from hills is assumed to follow the same regimen as flow in San Gabriel River, average annual values of inflow from that source during the 21- and 11-year periods are 510 and 4S0 acre-feet, respectively. SOUTH COASTAL BASIN INVESTIGATION 125 Annual import from Colorado Eiver, iiicliiding only water nsed in and around the Metropolitan Water District Water Softening- and Fil- tration plant, is assumed to equal the 1944-45 value. The average annual amount received from gravitj^ diversion in San Dimas Canyon is esti- mated to equal its historic 21-year average. Average import from Pomona Basin by one entity is assumed to equal one-half the amount which it is permitted to pump there, since amount imported in any one year varies inversely with the gravity supply available to the entity. Average annual import from other sources is assumed to equal the average for the four- year period, 1941-42 to 1944-45, inclusive, except in the case of water imported from Main San Gabriel Basin for purely domestic use, which is assumed equal to the present pumping right there. Estimated average annual import under present conditions totals 5,250 acre-feet. TABLE 5 8. IMPORT TO SAN DIMAS BASIN Year Acre-feet Year Acre-feet Year Acre-feet 1927-28 2,360 1933-34 3,670 1939-40 2,120 1928-29 2,940 1934-35 3,310 1940-41 3,060 1929-30 3,350 1935-36 4,080 1941-42 3,0G0 1930-31 3,780 1936-37 3,430 1042-43 4,420 1931-32 3,760 1937-38 3,990 1943-44 4,980 1932-33 3,850 1938-39 2,400 1944-45 5,400 Consumptive Use In Table 59 estimates of consumptive use based on culture surveys conducted by the Division of Water Resources in 1932 and 1942 are presented. Unit consumptive use is discussed in Chapter V. In addition to consumptive use so derived, it is estimated that evaporation from Pud- dingstone Reservoir averages 410 acre-feet annually during the 29-year period, 320 acre-feet in the 21-year, and 220 acre-feet in the 11-year period. A large part of the domestic culture is within the City of San Dimas. Industrial development is negligible. Natural vegetation on the little unused land ranges from moderately heavy brush to weeds and grass. 126 DIVISION OF WATER RESOURCES TABLE 59. ESTIMATED AVERAGE ANNUAL CONSUMPTIVE USE IN SAN DIMAS BASIN Unit con- sumptive 1932 19Jf2 Type of culture use, feet Acres Acre-feet Acres Acre-feet 7 9 25 32 4,228 8,033 4,219 8,016 22 37 22 37 3 9 3 9 245 368 263 394 263 236 ^ , , , Valley area Garden and field 1-3 Avocado and citrus 1.9 Deciduous 1-7 Irrigated grass 3.0 Domestic and industrial 1.5 Unirrigated 29- and 21-year periods 1.3 307 11-year period 1.286 338 Subtotal - — 4,768 4,768 __ 29- and 21-year periods 8,795 11-year period 8,794 Hill and mountain area Garden and field 0.0* Avocado and citrus 0.5* Deciduous 0.3* Domestic and industrial 0.1* Subtotal Grand total 4,9G0 _ 4,960 29- and 21-year period 8,886 11-year period 8,885 1 1 177 88 177 88 7 2 7 2 7 1 7 1 192 91 192 91 * Difference between irrigated culture and natural vegetation. Export In Table 60 estimated exports of ^Yater and sewage for eacli year since 1927-28 are presented. Water is exported to Glendora, Way Hill, Foothill, Live Oak and Pomona Basins, while filtration plant waste which is con- sidered sewage goes directly to the ocean. During the 11-year period, an annual average of 1,000 acre-feet of water was exported. Export of sew- age did not start until 1940-41. Estimated average annual export of water under present conditions is 960 acre-feet, and of sewage 1,370 acre-feet, a total of 2,330 acre-feet. It is assumed that 1944-45 sewage outflow and average annual export of water during the four-year period, 1941-42 to 1944-45, inclusive, represent present average annual export. Water Sewage'* 660 780 700 780 740 400 950 550 900 700 1,020 890 960 1,370 SOUTH COASTAL BASIN INVESTIGATION 127 TABLE 60. EXPORT FROM SAN DIM AS BASIN (Acre-feet) Year Water Sewage'* Year 1927-28 880 1936-37 1928-29 1,040 1937-38 1929-30 1,240 1938-39 1930-31 1,120 1939-40 1931-32 1,080 1940-41 1932-33 1,120 1941-42 1933-34 1,230 1942-43 1934-35 1,000 1943-44 1935-36 900 1944-45 • Waste from Metropolitan Water District Water Softening and Filtration Plant. Surface Outflotv Outflow on the surface includes part of the inflow from directly tribu- tary mountains and hills, part of that from Pomona and Foothill Basins, and runoff originating in precipitation on the overlying valley. It is esti- mated to average 1,210 acre-feet annually in the 29-year period, and 1,130 acre-feet in both the 21- and 11-year periods, as derived in Table 61. Inflow from mountains directly tributary to the basin, as well as the greater part of the inflow from Pomona and Foothill Basins, and runoff originating in precipitation on the easterly one-fourth of San Dimas Basin, is subject to storage and regulation in Puddingstone Reservoir. Twenty-nine- and 21-year average annual outflow from this source is estimated by assuming a combined irrigation draft from San Dimas Creek and Puddingstone Reservoir of 3,900 acre-feet annually, with a maximum of 3,000 acre-feet from the reservoir, and annual carry-over storage lim- ited to 7,000 acre-feet, and finally that 90 percent of resulting outflow from the reservoir reaches the lower boundary of the basin. Outflow originating in other sources is estimated by assuming that 90 percent of runoff from directly tributary hills draining in below the reservoir, and 5 percent of the precipitation on the overl^dng valley, leaves the basin. TABLE 61. SURFACE OUTFLOW FROM SAN DIMAS BASIN Average annual for 29-year period, 1904-0 5 to 193 2-3 3, inclusive; 21 -year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1537-38 inclusive (Acre-feet) 29-year 21-year 11-year period period period Estimated, originating in Release from Puddingstone Reservoir 550 Directly tributary hills 380 Precipitation on valley land 280 Total 1,210 1,130 1,130 » Includes some evaporation loss from reservoir. 470 480" 380 370 280 280 128 DIVISION OF WATER RESOURCES Excess Assuming that the 21-year period is the cycle of long-time mean supply, estimated annual excess is 810 acre-feet, as derived in Table 62. If the 29-year mean values are substituted in the table, the derived annual excess is 1,260 acre-feet. TABLE 62. ESTIMATED ANNUAL EXCESS IN SAN DIM AS BASIN UNDER PRESENT CONDITIONS ASSUMING THE 21-YEAR PERIOD, 1922-23 TO 1942-43, INCLUSIVE, TO BE ONE OF LONG-TIME MEAN SUPPLY (Acre-feet) Estimated Actual long-time 11-year mean annual base under • period present average Differ conditions annual ence 110 2,140 Average annual rise in storage during base period Items tending to increase the rise Precipitation 7,800 7,630 170 Surface inflow 3,000 2.780 220 Import 5,250 8,500 1,750 Subtotal to be added Items tending to decrease the rise Evaporation from Puddingstone Reservoir 320 220'' 100 Consumptive use 8,890 8,880 10 Surface outflow 1,130 1,130" Export 2,330 1,000 1,330 Subtotal to be subtracted Excess 1,440 810 a Outflow value includes some evaporation loss from Puddingstone Reservoir during ll-year period. Subsurface Outflotv Assuming that all items involved have been correctly evaluated, subsurface outflow during the 11-year base period, must, in accordance with principles set forth in Chapter V, have averaged 3,650 acre-feet annually, as derived in Table 63. SOUTH COASTAL BASIN INVESTIGATION 129 TABLE 63. ESTIMATED AVERAGE ANNUAL SUBSURFACE OUTFLOW FROM SAN DIMAS BASIN DURING THE 11-YEAR PERIOD, 1927-28 TO 1937-3 8, INCLUSIVE Acre-feet Water entering basin Precipitation 7,630 Surface inflow : 2.780 Import 3,500 Subsurface inflow 1,080 Subtotal 14,990 Increase in storage 110* Water leaving basin on surface Surface outflow 1,130'' Export 1,000 Evaporation from Puddingstone Reservoir 220'' Consumptive use 8,880 Subtotal 11,340 Subsurface Outflov^^ — to Central San Gabriel Valley Area 3,650 * Includes 770 acre-feet going into storage in Puddingstone Reservoir. '' Outflow value includes some of the evaporation loss from reservoir. SPADRA BASIN (30) Spadra Basin is located in the extreme west portion of Upper Santa Ana Valley, and covers about 6.6 square miles. It is bounded on the northwest and north by San Jose Hills, on the east by Chino Basin, on the south and southeast bv Puente Hills, and on the southwest bv Puente Basin. Topography is irregular, with average slope to the west and southwest of about 55 feet per mile. Elevations above sea level range from 625 to 920 feet. Soils covering the basin are about equally divided between light Hanford soils, and heavier soils of the Chino series. In San Jose Valley the latter predominate. Municipal development occu- pies about 16 percent of fhe area, about 63 percent is devoted to agri- culture, and the remainder is in a more or less natural state. The local water supply, utilized through pumping from ground water originates in precipitation on the valley, inflow from 3,820 acres of hills directly tributary to the basin, subsurface inflow 'from Chino Basin, and inflow on the surface from Pomona Basin, the greater part of the last named as flood flow in San Jose Creek. Imported water provides some addition to the supply. A considerable part of surface inflow and precipitation flows out into Puente Basin, together with some underflow. Sewage is exported for use in the same basin. In this basin, long-time mean annual net supply under present con- ditions is less than present annual demand, so an overdraft exists. Evaluation of items required * to estimate its amount follows. * Values of change in storage and precipitation, also required, are presented in Tables 5 and 7. 9—71061 130 DIVISION OF WATER RESOURCES Inflotv Estimated annual surface inflow to the basin averages 950 acre- feet, 940 acre-feet and 920 acre-feet in the 29-, 21- and 11-year periods, respectively, as derived in Table 64. The estimate of inflow from 3,820 acres of directly tributary hills is based on the assumption that 9 percent of precipitation on hills runs off.* A part of the surface outflow from Pomona Basin enters Spadra Basin. Estimated subsurface inflow from Chino Basin averages 710 acre- feet annually. TABLE 64. SURFACE INFLOW TO SPADRA BASIN Average annual for 29-year period, 1904-05 to 1932-33, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 1 1 -year period, 1927-28 to 1937-3 8, inclusive (Acre-feet) 29-year 21-year 11-year period period period From directly tributary hills Estimated » 500 500 490 From other basins Pomona 450" 440 430 Total ■ 950 940 920 ■ Includes a relatively small amount of underflow. *> 32-year mean value. iTtiport In Table 65 estimated values of imports of water from pumped sources in Pomona Basin for each year since 1927-28 are pre- sented. During the 11-year period it averaged 1,370 acre-feet annually. Estimated average annual import under present conditions is 1,800 acre-feet, equal to the historic average for the four-year period, 1941-42 to 1944-45, inclusive. TABLE 65. IMPORT TO SPADRA BASIN Year Acre-feet Year Acre-feet Tear Acre-feet 1927-28 1.880 1933-34 1.260 1939-40 1,910 1928-29 '_ 1,760 1934-35 1,130 1940-41 1,760 1929-30 1,600 1935-36 1,290 1941-42 1,600 1930-31 1,440 1936-37 1,060 1942-43 1.920 1931-32 1,320 1937-38 1,100 1943-44 1.920 1932-33 1,270 1938-39 1,460 1944-45 1,750 Constittiptive Use In Table 66 estimates of consumptive use based on culture surveys conducted bv the Division of Water Resources in 1932 and 1942 are presented. Unit consumptive use is discussed in Chapter V. A portion of the City of Pomona overlies the basin. Various agricultural crops are distributed over the area. The relatively small area of unirrigated land is covered largely by grass and weeds. * If runoff from hills is assumed to follow the same regimen of flow as San Gabriel River, average annual inflow from that source is 420 and 390 acre-feet for the 21- and 11-year periods, respectively. SOUTH COASTAL BASIN INVESTIGATION 131 TABLE 66. ESTIMATED AVERAGE ANNUAL CONSUMPTIVE USE IN SPADRA BASIN Type of culture Unit con- sumptive use, feet 1932 1942 Acres Acre-feet Acres Acre-feet Valley area Garden and field Avocado and citrus Deciduous Alfalfa Irrigated grass Domestic and industrial Unirrigated 29- and 21-year periods 11-year period Subtotal 29- and 21-year periods. 11-year period Hill area Avocado and citrus Deciduous Irrigated grass Domestic and industrial Subtotal Grand total 29- and 21-year periods- 11-year period 1.3 2.0 1.8 3.0 3.0 1.8 Ts 1.286 259 837 1,504 5 29 637 966 4,237 4,392 337 1,674 2,707 15 87 1,147 1,242 7,209 225 842 ,429 138 29 692 882 4,237 4,412 292 1,684 2,572 414 87 1,246 l'l47 7,442 0.7" 12 8 12 8 0.5* 15 8 15 8 1.7 » 104 177 104 177 0.4* 24 10 44 18 — 155 203 175 211 7,412 7,653 ■ Difference between irrigated culture and natural vegetation. Export 111 Table 67 estimated values of exports of sewage to Puente Basin for each year since 1927-28 are presented. No water is exported. During the 11-year period export of sewage averaged 200 acre-feet annually. Average annual export of sewage under present conditions is assumed equal to the 1944-45 value, or 510 acre-feet. TABLE 67. EXPORT FROM SPADRA BASIN (Acre-feet) Year Sewage Year Sewage Year Sewage 1927-28 —370 1933-34 250 1939-40 340 1928-29 180 1934-35 280 1940-41 360 1929-30 180 1935-36 290 1941-42 410 1930-31 240 1936-37 330 1942-43 480 1931-32 240 1937-38 330 1943-44 510 1932-33 230 1938-39 330 1944-45 510 132 DIVISION OF WATER RESOURCES Surface Outflotv Surface outflow includes part of the inflow from directly tributary hills, part of that from Pomona Basin and runoff originating in precipi- tation on the overlying valley. It is estimated to average 1,240 acre-feet annually in the 29- and 21-year periods, and 1,210 acre-feet in the 11-year period, as derived in Table 68. Inflow from directly tributary hills is distributed throughout the length of the basin. That from the north enters San Jose Wash, which rounds the easterly point of San Jose Hills out of Pomona Basin and traverses Spadra Basin for about five miles, roughly paralleling the northwesterly edge of the valley at a distance of about one-half mile. Inflow from Puente Hills on the south enters San Jose Creek directly. This stream lies approximately one-half mile southeast of and parallel to San Jose Wash, and joins it just below the Spadra-Puente Basin boundary. Neither stream is paved, but width of San Jose Wash is restricted by bank protection. Estimated surface outflow includes 80 percent of inflow from directly tributary hills, 90 percent of surface inflow from Pomona Basin, and 7 percent of precipitation on valley area within the basin.* TABLE 68. SURFACE OUTFLOW FROM SPADRA BASIN Average annual for 29-year period, 1904-05 to 1932-33, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38, inclusive (Acre-feet) 29-year 21-year 11-year period period period Estimated, originating in Directly tributary hills 400 400 390 Inflow from other basins 400 400 390 Precipitation on valley land 440 440 430 Total 1,240 1,240 1,210 Overdraft Assuming that the 21-year period is the cycle of long-time mean supply, estimated annual overdraft is 830 acre-feet, as derived in Table 69. If 29-year mean values are substituted in the table the derived value is 820 acre-feet. * Measured discharge at Station 2977 is used as a guide in determining the percentages. SOUTH COASTAL BASIN INVESTIGATION 133 TABLE 69. ESTIMATED ANNUAL OVERDRAFT IN SPADRA BASIN UNDER PRESENT CONDITIONS ASSUMING THE 21-YEAR PERIOD, 1922-23 TO 1942-43, INCLUSIVE, TO BE ONE OF LONG-TIME MEAN SUPPLY (Acre-feet) Estimated Actual long-time 11-year mean annual base under period present average Differ- conditions annual ence Average annual drop in storage during base period . 840 Items tending to increase the drop Consumptive use 7,650 7,410 240 Export 510 200 310 Surface outflow 1,240 1,210 30 Subtotal to be added 580 Items tending to decrease the drop Precipitation 6,270 6,130 140 Surface inflow 940 920 20 Import 1,800 1,370 430 Subtotal to be subtracted 590 Overdraft 830 Subsurface Outflow Assuming that all items involved have been correctly evaluated, sub- surface outflow during the 11-year period must, in accordance with principles set forth in Chapter V, have averaged 1,150 acre-feet annually, as derived in Table 70. TABLE 70. ESTIMATED AVERAGE ANNUAL SUBSURFACE OUTFLOW FROM SPADRA BASIN DURING THE 11-YEAR PERIOD, 1927-28 TO 1937-3 8, INCLUSIVE Acre-feet Water entering basin Precipitation 6,130 Surface inflow 920 Import 1,370 Subsurface inflow 710 Water coming from storage in basin 840 Subtotal 9,970 Water leaving basin on surface Surface outflow 1,210 Exported sewage 200 Consumptive use 7,410 Subtotal 8,820 Subsurface Outflow — to Puente Basin 1,150 134 DIVISION OF WATER RESOURCES PUENTE BASIN (15) Puente Basin occupies the lower portion of San Jose Valley, a south- easterly extension of San Gabriel Valley, and covers about 20 square miles. It is bounded on the southwest, south and southeast by Puente Hills, on the north and northwest by Main San Gabriel Basin and San Jose Hills, and on the northeast by Spadra Basin. Lines of contact between valley and hill lands, both to the north and south, are very irregular. Slopes downward from the hills are generally toward San Jose Creek, which traverses the length of the valley, and vary greatly both in steep- ness and direction. Slope down the axis of the valley averages about 30 feet per mile. Elevations in the valley range between 290 and 975 feet above sea level. Soils are mostly heavier members of the Chino series, and the somewhat lighter and more pervious Yolo loam. About 3 percent of the area is covered by culture of a municipal type, about 68 per cent is devoted to agriculture, and about 29 percent is in a more or less natural state. The local water supply, utilized almost entirely through pumping from ground water, originates in precipitation on valley land, inflow from 17,280 acres of hills directly tributary to the basin, and inflow both under- ground and on the surface from Spadra Basin, the greater part of the last named as flood flow in San Jose Creek. Imported water and sewage provide a relatively large addition to the supply. A considerable part of surface inflow and precipitation flows out into Main San Gabriel Basin, together with comparatively large under- flow. There is no export of water or sewage. In this basin, long-time mean annual net supply under present con- ditions is a little greater than present annual demand, so a small excess exists. Evaluation of items required * to estimate its amount follows. . Inflotv Estimated annual surface inflow to the basin averages 3,830 acre- feet in the 29- and 21-year periods and 3,750 acre-feet during the 11-year period, as derived in Table 71. The estimate of inflow from 17,280 acres of hills directly tributary to the basin is based on the assumption that 10 percent of precipitation on hills runs off.t All surface and subsurface outflow from Spadra Basin enters Puente Basin. Estimated subsurface inflow from this source during the 11-year period averages 1,150 acre-feet annually. * Values of change in storage and precipitation, also required, are presented in Tables 5 and 7. t If inflow from hills is assumed to follow the same regimen of flow as San Gabriel River, average inflow during the 21 -year period is 2,150 acre-feet annually, and during the 11-year period, 2,020 acre-feet. SOUTH COASTAL BASIN INVESTIGATION 135 TABLE 71. SURFACE INFLOW TO PUENTE BASIN Average annual for 29-year period, 1904-05 to 1932-33, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38, inclusive (^Acre-feet) 29-year 21-year 11-year period period period From directly tributary hills Estimated » 2,590 2,590 From other basins Spadra 1,240 1,240 Total* 3,830 3,830 2,540 1,210 3,750 • Includes a relatively small amount of underflow. Itnport In Table 72 estimated values of imports of water and sewage for each year since 1927-28 are presented. Water is imported from pumped sources in Main San Gabriel Basin and from Colorado River, while sewage inflow is from Chino, Pomona and Spadra Basins. During the 11-year period, an annual average of 2,900 acre-feet of water, and 1,120 acre-feet of sewage was imported, a total of 4,020 acre-feet. It is estimated that average annual import of water under present conditions is 3,280 acre-feet, and of sewage, 2,360 acre-feet, a total of 5,640 acre-feet. The 1944-45 import of Colorado River water and of sew- age, and the annual average import of other water during the four-year period, 1941-42 to 1944-45, inclusive, are assumed to constitute the average under present conditions. TABLE 72. IMPORT TO PUENTE BASIN (Acre-feet) Year Water Sewage Year Water Sewage 1927-28 2,620 340 1928-29 2,620 980 1929-30 2,920 980 1930-31 3,170 1,120 1931-32 3,010 1,130 1932-33 2,910 1,060 1933-34 3,290 1,130 1934-35 2,230 1,300 1935-36 3,280 1,310 1936-37 2,900 1,500 1937-38 2,970 1,480 1938-39 3,210 1,480 1939-40 2,520 1,530 1940-41 2,550 1,640 1941-42 2.710 1,870 1942-43 3,390 2,240 1943-44 3,370 2,360 1944-45 3,300 2,360 Consumptive Use In Table 73 estimates of consumptive use based on culture surveys conducted by the Division of Water Resources in 1932 and 1942 are pre- sented. Unit consumptive use is discussed in Chapter V. Domestic use is small, as is industrial development. Citrus occupies much of the higher ground, with other crops intermingled in the valley. Natural vegetation growing on unused land is largely weeds and grass, with a few small area^ of water-loving trees and brush along San Jose Creek. 136 DIVISION OF WATER RESOURCES TABLE 73. ESTIMATED AVERAGE ANNUAL CONSUMPTIVE USE IN PUENTE BASIN Unit con- sumptive 1932 1942 Type of culture use, feet Acres Acre-feet Acres Acre-feet Valley and folded area Garden and field 1.3 374 486 483 628 Avocado and citrus 1.9 3,831 7,279 4,037 7,670 Deciduous 1.7 4,305 7,318 3,774 6,416 Alfalfa 3.0 233 699 572 1,716 Domestic and industrial _ . 1.5 282 4,001 423 334 3,826 501 Unirrieated _ 29- and 21-year periods 1.2 4,591 11-year period 1.187 4,749 Subtotal 13,026 13,026 29- and 21-year periods __ — — — — — — — — — — . 21,522 11-year period 20,954 Hill area Garden and field 0- 0.5* 47 696 348 37 754 Avocado and citrus 377 Deciduous 0.3* 74 22 84 25 Alfalfa 1.6* 3 5 13 21 Subtotal 820 375 888 423 Grand total 13,846 13,914 29- and 21-year periods __ _ , , 21,945 11-year period 21,329 » Difference between irrigated culture and natural vegetation. Surface Outflow Outflow on the surface includes part of the inflow from directly tributary hills, part of that from Spadra Basin, and runoff originating in precipitation on the overlying valley. It is estimated to average 3,810 acre-feet annually in both the 29- and 21-year periods and 3,730 acre-feet in the 11-year period, as derived in Table 74. Inflow from San Jose Hills on the north is well distributed in many small streams, and enters San Jose Creek soon after emerging from the hills. That from Puente Hills, also well distributed, flows for an average of two miles before reaching the channel. A part of this flow is along paved roads. The unpaved channel of San Jose Creek is 11 miles long within the basin. In some places water table and channel bed coincide, while elsewhere percolation occurs. Inflow from Spadra Basin is in San Jose Wash and San Jose Creek, which join just after entering Puente Basin. It is estimated that outflow* includes 75 percent of inflow from directly tributary hills, 75 percent of inflow from Spadra Basin, and 5 percent of precipitation on overlying valley land.* ♦Measured discharge at Station 2977 is used as a guide In determining percentages. SOUTH COASTAL BASIN INVESTIGATION 137 TABLE 74. SURFACE OUTFLOW FROM PUENTE BASIN Average annual for 29-year period, 1904-05 to 1932-33, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-3 8, inclusive (Acre-feet) 29-year 21-year 11-year period period period Estimated, originating in Directly tributary hills 1,940 1,940 1,900 Inflow from other basins 930 930 910 Precipitation on valley and folded land 940 940 920 Total __ 3,810 3,810 3,730 Excess Assuming that either the 21- or 29-year period is the cycle of long- time mean suppl}^, estimated annual excess is 1,080 acre-feet, as derived in Table 75. The City of Puente and surrounding area is included in Los Angeles County Sanitation District No. 15, recently formed. As sewer systems are installed in the area, and sewage exported to the ocean, indicated excess for present conditions will be decreased or eliminated entirely by the sewage outflow. TABLE 75. ESTIMATED ANNUAL EXCESS IN PUENTE BASIN UNDER PRESENT CONDITIONS, ASSUMING THE 21-YEAR PERIOD, 1922-23 TO 1942-43, INCLUSIVE, TO BE ONE OF LONG-TIME MEAN SUPPLY (Acre-feet) Estimated Actual ^ long-time 11-year mean annual hase under period present average Differ- conditions annual ence Average annual drop in storage during base period 340 Items tending to increase the drop Consumptive use 21,940 21,330 610 Surface outflow 3,810 3,730 80 Subtotal to be added 690 Items tending to decrease the drop Precipitation 18,950 18,540 410 Surface inflow 3,830 3,750 80 Import 5,640 4,020 1,620 Subtotal to be subtracted 2,110 Excess 1,080 138 DIVISION OF WATER RESOURCES Subsurface Outflow Assuming that all items involved have been correctly evaluated, sub- surface outflow during the 11 -year base period must, in accordance with principles set forth in Chapter V, have averaged 2,740 acre-feet annually, as derived in Table 76. TABLE 76. ESTIMATED AVERAGE ANNUAL SUBSURFACE OUTFLOW FROM PUENTE BASIN DURING THE 11-YEAR PERIOD, 1927-28 TO 1937-38, INCLUSIVE Acre-feet Water entering basin Precipitation 18,540 Surface inflow 3,750 Imported water 2,900 Imported sewage 1,120 Subsurface inflow 1,150 Water coming from storage in basin 340 Subtotal 27,800 Water leaving basin on surface Surface outflow 3.730 Consumptive use 21,330 Subtotal 25,060 Subsurface Outflow — to Central San Gabriel Valley Area 2.740 CENTRAL SAN GABRIEL VALLEY AREA Main San Gabriel Basin (6) , Upper Canyon Basin (9) Lower Canyon Basin (10) While effective barriers separate these three basins, they operate as a unit and are therefore combined in this discussion. They occupy all the central portion of San Gabriel Valley, and cover about 124 square miles. The area is bounded on the north by San Gabriel Mountains and Ravmond Fault, bevond which lies Eavmond Basin Area, on the east by Glendora, Wav Hill and San Dimas Basins, on the southeast by San Jose Hills, on the south by Puente Basin and Puente Hills, and on the southwest and west by Merced Hills, San Rafael Hills and Whittier Narrows, beyond which lies Montebello Forebay Area. Topography is relatively smooth throughout. In the upper outwash area of San Gabriel River the surface is cut by innumerable shallow channels, ditches and other depressions. Slope is generally toward Whittier Narrows. Near the Narrows it averages 20 feet per mile, and gradually increases to 75 feet per mile near Azusa, and 125 feet per mile in the Monrovia-Duarte area. Debris cones of San Gabriel River, and of groups of smaller streams both to the east and west, are well defined almost to the Narrows. Elevations above sea level range from 200 feet at the Narrows, to 800 feet near Monrovia and 900 feet in the vicinity of Glendora. Soils are mostly lighter members of the Hanford series, with a few areas of still more open Tujunga soils along San Gabriel River. In the area lying west of Eaton SOUTH COASTAL BASIN INVESTIGATION 139 Wash, somewhat heavier Ramona soils predominate, while below El Monte in the zone of rising water there are considerable areas of Chino soils. Municipal development occupies about 35 percent of the area, about 41 percent is devoted to agriculture, and the remainder is in a more or less natural state. The local water supply, utilized to a considerable extent through diversion from surface streams, but more through pumping from ground water, originates in precipitation on valley lands, inflow from 242 square miles of mountains and 5,530 acres of hills directly tributary to the basin, and inflow both underground and on the surface from Raymond Basin Area, and from Glendora, Way Hill, San Dimas and Puente Basins. San Gabriel River is by far the largest stream discharging into the area. Imported water provides a relatively small addition to the supply. Sewage is imported from AVestern Unit of Raymond Basin Area and from Los Angeles Narrows Basin. A considerable part of surface inflow and precipitation flows out into Montebello Forebay Area, together with comparatively large underflow, and water is exported in relatively large amount to La Habra and Puente Basins and to Montebello Forebay Area, and in less amount to Glendora, Way Hill, San Dimas and Los Angeles Narrows Basins. During the period, 1933-34 through 1940-41, export to Western Unit of Raymond Basin Area was large, but at present it is very small. Sewage outflow, the greater part of it in Rio Hondo, is relatively large. As demonstrated by the comparison depicted on Plate 24, Main San Gabriel Basin, the downstream member of this group, is one in which outflow of rising water responds quickly to changes in elevation of the water table. Where this is true, neither excess nor overdraft is considered to exist. Supply to Upper and Lower Canyon Basins is so large, and their carry-over storage capacity so small, that it is assumed that there too neither overdraft nor excess exists. Main San Gabriel Basin serves as a partial regulator of supply to the area below Whittier Narrows, so long- time mean surface outflow to Montebello Forebay Area under present conditions is the value herein estimated. Evaluation of items required* to estimate its amount follows. Inflotv Estimated annual surface inflow to the area averages 155,700 acre- feet, 131,370 acre-feet and 122,600 acre-feet in the 29-, 21- and 11-year periods, respectivel}^, as derived in Table 77. Inflow 'from directly tributary mountains above gaging stations at which flow was measured during all or part of each period is tabulated below. Twenty-nine year values for Fish, Rogers and Sawpit Creeks are derived by comparison with San Gabriel River. The evaporation loss shown is that from three mountain reservoirs on San Gabriel River. * Values of change in storage and precipitation, also required, are presented in Tables 5 and 7. 140 DIVISION OF WATER RESOURCES Mean annual infloic in acre- feet 29-year 21-year 11-year Stream Station period period period San Gabriel River 4294,4313 130,900" 108,010* 99,030'' Rogers Creek 4293 2,770 2,470 2,060 Fish Creek 4273 3,730 3,410 3,080 Sa^vpit Creek 4202 2,330» 2,080* 1,680'» Subtotal 139,730 115,970 105,850 Estimated evaporation from San Gabriel River Reservoirs 2,200 2,200 Remainder 137,530 113,770 105,850 » Full natural flow as reconstructed, corrected for reservoir operation. '' Actual inflow including diversions, but not corrected for reservoir operation. The estimate of 29-year mean annual inflow from 6,230 acres of mountains directly tributary to the area, and downstream from gaging stations at which above inflow was measured, is based on the assump- tion that, if water is available, average annual consumptive use on mountain area is 20 inches, inflow however being never less than 8 percent of precipitation on the mountains. The 11-year value is esti- mated to be 0.78 times the 29-year mean, this being the ratio between 11- and 29-year mean discharge of San Gabriel River. The corresponding ratio for the 21-year period is 0.83. Estimated inflow from 5,530 acres of directly tributary hills is 10 percent of the precipitation thereon.* Inflow on the surface from other basins includes all surface outflow from Eastern Unit of Raymond Basin Area, and from Glendora, "Way Hill, San Dimas and Puente Basins, and part of that from Western Unit of Raymond Basin Area. Subsurface inflow, averaging 13,800 acre- feet annually during the 11-year period, includes underflow from Ray- mond Basin Area, and from Glendora, Way Hill, San Dimas and Puente Basins. * If runoff from hills is assumed to follow the same regimen as flow in San Gabriel River, average annual runoff during 21- and 11-year periods is 670 and 630 acre-feet, respectively. SOUTH COASTAL BASIN INVESTIGATION 141 TABLE 77. INFLOW TO CENTRAL SAN GABRIEL VALLEY AREA Average annual for 29-year period, 1904-0 5 to 193 2-3 3, inclusive; 21 -year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38, inclusive (Acre-feet) 29-year 21-year 11-year period period period 5,330 5,270 4,180 3,510 1,130 1,190 230 210 1,130 1,130 8,810 3,730 131,370 122,600 2,860 ^^_ ^' 240 ^1—..^ 3,420 _^ ^ 890 _^ 3,650 2,740 Surface Inflow From directly tributary mountains Measured during all or part of period 137,530 113,770 105,850 Estimated* 1,180 980 920 From directly tributary hills Estimated* 810 810 790 From other basins Western Unit of Raymond Basin Area 5,180 Eastern Unit of Raymond Basin Area 4,410 Glendora 1,320 Way Hill 250 San Dimas 1,210 Puente 3,810 Total 155,700 Subsurface inflow from other basins Western Unit of Raymond Basin Area Eastern Unit of Raymond Basin Area Glendora Way Hill San Dimas Puente Total ' 13,800 * Includes a relatively small amount of underflow. Import In Table 78 estimated values of imports of water and sewage for each year since 1927-28 are presented. Water is imported from Eastern and Western Units of Raymond Basin Area, from Montebello Forebay Area, and from Way Hill, Pomona and Los Angeles Narrows Basins, while sewage inflow is from Western Unit of Raymond Basin Area and Los Angeles Narrows Basin. During the 11-year period an annual average of 12,650 acre-feet of water and 5,600 acre-feet of sewage was imported, a total of 18,250 acre-feet. It is estimated that average annual import of water under present conditions is 8,000 acre-feet, and of sewage 7,780 acre-feet, a total of 15,780 acre-feet. Present import from Western Unit of Raymond Basin Area is based upon decreed rights of exporters from the Western Unit, use of water during 1944-45 in their service areas within the Unit, and amount released by them for Fiscal Year 1946-47 under the Water Exchange Agreement. Present annual import from Eastern Unit of Raymond Basin Area is the calculated amount available for export from said Unit without exceeding safe yield. Present annual import from Los Angeles Narrows Basin is assumed to be that of 1944-45. Present import from Pomona and Way Hill Basins and Montebello Forebay Area is 142 DIVISION OF WATER RESOURCES assumed to equal the historic average for the four-year period, 1941-42 to 1944-45, inclusive. Present annual average sewage import is assumed to be that of 1944-45. TABLE 7 8. IMPORT TO CENTRAL SAN GABRIEL VALLEY AREA (Acre-feet) Year Water Seicage Year Water Sewage 1927-28 14.1S0 4.740 1936-37 11,510 6,200 1928-29 13,730 5,130 1937-38 11,320 6,380 1929-30 13,200 5,120 1938-39 11.380 6,560 1930-31 13,540 5,370 1939-40 12,120 6,670 1931-32 12.390 5.780 1940-41 11.990 6,990 1932-33 12.390 5,540 1941-42 13,260 6.840 1933-34 13,760 5.610 1942-43 14,300 7,050 1934-35 10,790 5,770 1943-44 13,900 7,470 1935-36 12,380 5,940 1944-45 9,990 7,780 Consumptive Use In Table 79 estimates of consumptive use based on culture surveys conducted by the Division of Water Resources in 1932 and 1942 are pre- sented. Unit consumptive use is discussed in Chapter V. The greater part of usable land in the area is occupied. Municipal development in the west- erly portion of the area includes the cities of Alhambra, El Monte, Mon- terey Park, San Gabriel, San Marino, Arcadia, Monrovia, and some unin- corporated communities. That in the easterly portion includes the Cities of Azusa and Covina, together with the unincorporated town of Baldwin Park. By far the largest part of the municipal development lies west of San Gabriel River. 'industrial development is largely in the City of Alhambra, and while it materially increases the demand for water, the amount actually consumed is relatively small. Citrus occupies much of the higher ground, and alfalfa, garden and field crops are produced on the smooth, fine textured soils of lower lands. Natural vegetation is largely light brush and grass, with a considerable area of water-loving vegetation just above T^liittier Narrows. SOUTH COASTAL BASIN INVESTIGATION 143 TABLE 79. ESTIMATED AVERAGE ANNUAL CONSUMPTIVE USE IN CENTRAL SAN GABRIEL VALLEY AREA Type of culture Valley and folded area Garden and field Avocado and citrus Deciduous Alfalfa Irrigated grass Domestic and industrial Natural water-loving vegetation. Unirrigated 29- and 21-year periods 11-year period Subtotal 29- and 21-year periods.-. 11-year period Hill and mountain area Garden and field Avocado and citrus Deciduous Alfalfa Irrigated grass Domestic and industrial Subtotal Grand total 29- and 21-year periods 11-year period Unit con- sumptive ; 1932 19J use, feet Acres Acre- feet Acres Acre-feet 1.3 8,379 10,893 8,028 10,436 1.9 15,017 28,532 14,791 28,103 1.7 12,702 21,593 6,849 11,643 3.0 1,546 4,638 1,986 5,958 3.0 474 1,422 854 2,562 1.5 20,540 30,810 27,913 41,870 4.0 934 3,736 934 3,736 19,990 18,227 1.2 — . — __ 21,872 1.187 23,728 79,582 79,582 .^ «. — — ^ 126,180 125,352 O"* 8 8 0.6 => 504 302 517 310 0.4" 34 14 34 14 1.7" 5 8 5 8 1.7" 52 88 52 88 0.2" 880 176 974 195 1,483 588 1,590 615 81,065 81,172 _— .__ ^mm.^^ — -...^ 126,795 125,940 • Diflference between irrigated culture and natural vegetation. Export In Table 80, estimated exports of water and sewage for each year since 1927-28 are presented. Water is exported to Western Unit of Ray- mond Basin Area, to Montebello Forebay Area, and to Glendora, Way Hill, San Dimas, Puente, La Habra and Los Angeles Narrows Basins, while that part of the sewage which is herein treated as an export goes directly to the ocean. Flow through Whittier Narrows in various ditches, and sewage from the Tri-City plant and from El Monte which enters Rio Hondo above the Narrows, are treated as a part of the surface out- flow rather than as exports. Water diverted at Morris Reservoir from 1933-34 to 1940-41, inclusive, for use in Raymond Basin Area is con- sidered an export from Central San Gabriel Valley Area. During the 11-year period an annual average of 23,420 acre-feet of water and 830 acre-feet of sewage was exported, a total of 24,250 acre-feet. It is estimated that average annual export of water under present conditions is 20,630 acre-feet, and of sewage 2,470 acre-feet, a total of 23,100 acre-feet. It is assumed that present export of water to Western Unit of Raymond Basin Area, and present sewage outflow are equal to their 1944-45 values. Present export to Glendora Basin is estimated to 144 DIVISION OF WATER RESOURCES equal the historic annual average for the four-year period, 1941-42 to 1944-45, inclusive, phis the difference between average annual diversions from Big and Little Dalton Creeks for the four-year period, and for the 21-year period. Present export to TVay Hill, Puente, La Habra and Los Angeles Narrows Basins and to Montebello Forebay Area is estimated to equal the annual average for the four-year period, 1941-42 to 1944-45, inclusive. Present export to San Dimas Basin for domestic purposes is assumed to equal the amount available under present arrangements, since demand for domestic water is increasing rapidly. TABLE 80. EXPORT FROM CENTRAL SAN GABRIEL VALLEY AREA (Acre-feet) Year Water Sewage Year Waier Sewage 1927-28 17,000 1928-29 18,730 1929-30 20,500 1930-31 22.320 1931-32 21.830 1932-33 23.040 1933-34 28,130 1934-35 22.470 1935-36 24.490 670 1936-37 27,580 990 750 1937-38 31.510 1,130 790 1938-39 34,350 1,220 780 1939-40 33,170 1,520 790 1940-41 20,960 1,840 790 1941-42— 18,860 2,020 730 1942-43 20,300 2,720 830 1943-44 21,180 2,740 840 1944-45 19,610 2,470 Surface Otitfloiv During 11 -Year Period During the 11-year period by far the larger part of outflow from the area was measured at or near T^^hittier Narrows. Of this, an average annual discharge of 42,770 acre-feet was carried by Rio Hondo, 12,140 acre-feet by Rio Hondo Slough, and 37,010 acre-feet by San Gabriel River. The total included 37,540 acre-feet of rising water, approximately 8,000 acre-feet of effluent from the Tri-City Sewage Treatment Plant, a small amount not exceeding 700 acre-feet, came from City of El Monte sewage, and the remainder was runoff which flowed across Central San Gabriel Valley Area on the surface. A considerable part of the rising water is diverted just above the Narrows and carried through in ditches, but all is here treated as surface outflow. In addition to measured flow, estimated average annual outflow includes 130 acre-feet of water originating in hills, and 630 acre-feet originating in precipitation on the valley, assuming that 10 percent of precipitation on the extreme westerly portion of the basin, 5 percent of that on remaining valley lands, and 90 percent of inflow from hills leaves the basin. Estimated total average annual surface outflow during the 11-year period is 92,680 acre-feet. Subsurface Outflotv Assuming that all items involved have been correctly evaluated, subsurface outflow during the 11-year base period, must, in accordance with principles set forth in Chapter V, have averaged 23,280 acre-feet annually, as derived in Table 81. In an analysis involving the use of measured rising water and water table slopes, James Kimble estimated SOUTH COASTAL BASIN INVESTIGATION 145 the subsurface outflow at 23,170 acre-feet per year.* In an earlier study of San Gabriel Valley Water supply, the State Division of Water Rights used a value of 25,000 acre-feet, t TABLE 81. ESTIMATED AVERAGE ANNUAL SUBSURFACE OUTFLOW FROM CENTRAL SAN GABRIEL VALLEY AREA DURING THE 11 -YEAR PERIOD, 1927-28 TO 1937-38, INCLUSIVE Acre-feet Water entering area Precipitation 115,860 Surface inflotv^ 122,600 Imported water 12,650 Imported sewage 5,600 Subsurface inflow 13,800 Subtotal 270,510 Increase in storage 4,360 Water leaving basin on surface Surface outflow 92,680 Exported water 23,420 Exported sewage 830 Comsumptive use 125,940 Subtotal 247,230 Subsurface Outflow — to Montebello Forebay Area 23,280 Long-titne Mean Surface Outflow The hydrologic equation used in the preceding article applies equally well in all periods. As has been stated, it is considered that neither overdraft nor excess exists. Long-time mean surface outflow, herein estimated, is that quantity which balances all other items involved. Assuming the 21-year period to be one of long-time mean supply, estimated mean annual surface outflow is 106,200 acre-feet, as derived in Table 82. If 29-3^ear mean values are substituted the derived outflow is 130,530 acre-feet. Extensive sewerage improvements have recently been authorized, consisting of outfall lines 1X) the ocean, and sewer systems for presently unsewered areas. As these are completed, long-time mean outflow will be decreased by the amount of increased sewage export and elimination of effective sewage import. * American Geophysical Union, 1936, "Underflow at Whittier Narrows, etc." t Bulletin No. 7, San Gabriel Investigation, 1928. 10—71061 146 DIVISTON OF WATER RESOURCES TABLE 82. ESTIMATED LONG-TIME MEAN ANNUAL SURFACE OUTFLOW FROM CENTRAL SAN GABRIEL VALLEY AREA ASSUMING THE 21 -YEAR PERIOD, 1922-23 TO 1942-43, INCLUSIVE, TO BE ONE OF LONG-TIME MEAN SUPPLY Acre-feet Supply to area Precipitation 118,430 Surface inflow 131,370 Import 15,780 Subsurface inflow 13,800 Subtotal ' 279,380 Demand on area Consumptive use 126,800 Export 23,100 Subsurface outflow 23,280 Subtotal 173,180 Surface Outflow 106,200 LA HABRA BASIN (34) La Habra Basin is located in the northeast portion of the Coastal Plain, and covers about 40 square miles. It is bounded on the west by Montebello Forebay Area, on the northeast and north by Puente Hills, on the east by Yorba Linda Basin, and on the south by Central Coastal Plain Pressure Area and Santa Ana Forebay Area. Topography is very irregular, with slopes generally to the south averaging about 150 feet per mile, but varying widely either way from this figure for short dis- tances. Elevations above sea level range from 115 to 800 feet. Soils are mostly medium textured and heavy members of the Yolo and Ramona series, and are only moderately pervious. Municipal development occu- pies about 13 percent of the area, about 63 percent is devoted to agri- culture, and the remainder is in a more or less natural state. The local water supply, utilized almost entirely through pumping from ground water, originates in precipitation on the overlying valley, inflow from 18,760 acres of hills directly tributary to the basin, and very small inflow on the surface from Montebeilo Forebay Area. Imported water provides a large addition to the supply. A considerable part of the surface inflow and precipitation on the valley flows out into Central Coastal Plain Pressure Area and to Santa Ana Forebay Area, together with some underflow to Montebello Forebay Area. Water is exported in relatively large amount to Central Coastal Plain Pressure Area, and in lesser quantity to Yorba Linda Basin and Montebello Forebay Area. A substantial amount of sewage is exported to the pressure area and to the ocean. In this basin, long-time mean annual net supply under present con- ditions is less than present annual demand, so an overdraft exists. Evaluation of items required* to estimate its amount follows. * Values of change in storage and precipitation, also required, are presented In Tables 5 and 7. SOUTH COASTAL BASIN INVESTIGATION 147 Inflow Estimated annual surface inflow averages 2,650 acre-feet, 2,760 acre- feet and 2,680 acre-feet in the 29-, 21- and 11-year periods, respectively, as derived in Table 83. The estimate of inflow from 18,760 acres of directly tributary hills is based on the assumption that 10 percent of precipitation thereon runs off.t Subsurface inflow, other than that indicated by note in Table 83, is negligible. TABLE 83. SURFACE INFLOW TO LA HABRA BASIN Average annual for 29-year period, 1904-0 5 to 193 2-3 3, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38, inclusive (Acre-feet) 29-year 21-year 11-year period period period From directly tributary hills Estimated'' 2,590 2,700 2,620 From other basins Montebello Forebay Area 60 60 60 Total 2,650 2,760 2,680 » Includes a relatively small amount of underflow. Import In Table 84 estimated imports of w^ater for each year since 1927-28 are presented. There is no import of sewage. Gravity and pumped water is imported from Central San Gabriel Valley Area and Montebello For>ebay Area. During the 11-year period, an annual average of 18,400 acre-feet was imported. Estimated average annual import of water under present conditions is 18,830 acre-feet, equal to the average for the four- year period, 1941-42 to 1944-45, inclusive. TABLE 84. IMPORT TO LA HABRA BASIN Year Acre-feet Year Acre-feet Year Acre-feet 1927-28 15,830 1933-34 19,540 1939-40 17,720 1928-29 18,270 1934-35 14,960 1940-41 17,230 1929-30 18,890 1935-36 20,340 1941-42 17,960 1930-31 19,490 1936-37 17,860 1942-43 19,470 1931-32 19,180 1937-38 18,190 1943-44 19,360 1932-33 19,880 1938-39 19,300 1944-45 18,520 Consumptive Use In Table 85 estimates of consumptive use based on culture surveys conducted by the Division of Water Resources in 1932 and 1942 are pre- sented. Unit consumptive use is discussed in Chapter V. The cities of Whittier, La Ilabra and Brea overlie the basin. Avocado and citrus occupy t If runoff from hills is assumed to follow the same regimen as flow in San Gabriel River, inflow from that source is 2,150 and 2,020 acre-feet in the 21- and 11-year periods, respectively. 148 DIVISION OF WATER RESOURCES by far the greater part of irrigated lands, both in the valley and on tributary hills. Unirrigated area is covered by light brush, weeds, and grass. TABLE 85. ESTIMATED AVERAGE ANNUAL CONSUMPTIVE USE IN LA HABRA BASIN Type of culture Unit con- sumptive 1932 19J,2 use, feet Acres Acre-feet Acres Acre-feet Valley and folded area Garden and field 1.2 Avocado and citrus 1.9 Deciduous 1.7 Alfalfa 2.5 Irrigated grass 2.5 Domestic and industrial 1.4 Unirrigated 29-year period 1.1 21-year period 1.124 11-year period 1.108 Subtotal 29-year period 21-year period 11-year period Hill area Garden and field 0.0 "^ Avocado and citrus 0.7 '^ Irrigated grass 1.3 * Domestic and industrial 2 * Subtotal Grand total 29-year period 21-year period 11-year period 914 1,097 830 996 12,954 24.613 13,270 25,213 2,701 4,592 1,735 2,950 211 528 211 528 212 530 212 530 3,005 4,207 3,240 4,536 5,651 6,150 . 6,765 6,913 6,261 25,648 25,648 _ 41,518 __^^ 41,666 41,828 — 10 10 1,089 702 1,284 899 47 61 47 61 97 19 132 26 1,243 26,891 842 1,473 42,670 27,121 986 42,504 42,652 » Difference between irrigated culture and natural vegetation. Export In Table 86 estimated exports of water and sewage for each year since 1927-28 are presented. Water is exported to Central Coastal Plain Pressure Area, Montebello Forebay Area and Yorba Linda Basin. Sewage from the City of "Whittier is exported to Central Coastal Plain pressure area, and that from the City of La Plabra goes to the ocean. During the 11-year period an annual average of 1,520 acre-feet of water and 1,420 acre-feet of sewage was exported, a total of 2,940 acre-feet. Estimated average annual export of water under present conditions is 1,100 acre-feet, equal to the average for the four-year period, 1941-42 to 1944-45, inclusive. Present annual export of sewage is estimated to be 2,340 acre-feet, the same as in 1944-45. Total estimated average annual export under present conditions is then 3,440 acre-feet. SOUTH COASTAL BASIN INVESTIGATION 149 TABLE 86. EXPORT FROM LA HABRA BASIN (Acre-feet) Year Water Sewage Year Water Sewage 1927-28 1,180 1,300 1936-37 1,430 1,540 1928-29 1,230 1,340 1937-38 1,270 1,560 1929-30 1,250 1,380 1938-39 1,300 1,530 1930-31 2,070 1,380 1939-40 1,110 1,590 1931-32 1,790 1,380 1940-41 1,100 1,770 1932-33 1,750 1,380 1941-42 1,010 1,780 1933-34 1,640 1,420 1942-43 1.110 1,860 1934-35 1,350 1,480 1943-44 1,180 1,910 1935-36 1,720 1,480 1944-45 1,090 2,340 Surface Outflotv Outflow on the surface includes part of the inflow from directly tributary hills, part of that from Montebello Forebay Area, and runoff originating in precipitation on the overlying valley. It is estimated to average 2,520 acre-feet, 2,860 acre-feet and 2,580 acre-feet in the 29-, 21- and 11-year periods, respectively, as derived in Table 87. Inflow from the south face of Puente Hills, directly tributary to this basin, flows in several streams three to five miles across the basin, partly along paved streets in and adjacent to the cities of Whittier, La Habra and Brea, and partly in unpaved channels. Small inflow from Montebello Forebay Area enters La Habra Basin about three and one- half miles from its point of outfloAv. Runoff in Brea Creek has been measured at Stations 1171 and 1172 since 1930-31, with exception of four months in 1939-40. That in East Fullerton Creek has been measured at stations 15611 and 1192 since 1930-41. Runoff for years prior to 1930-31, and for missing years since, is estimated from precipitation indices for the Coastal Plain Group, using rainfall-runoff relationships established during years of record. Runoff at gaging stations on Brea Creek is assumed to represent outflow from the basin. That proportion of runoff at gaging stations on East Fullerton Creek which originates within La Habra Basin is estimated to equal the proportion of the precipitation on the watershed which falls within the basin. Additional outflow is assumed to include 90 percent of the inflow from about 450 acres of hills at the extreme west end of the basin, and 50 percent of that from remaining hills not tributary to Brea Creek, together with 5 percent of precipitation on overlying valley land. TABLE 87. SURFACE OUTFLOW FROM LA HABRA BASIN Average annual for 29-year period, 1904-05 to 1932-33, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38, inclusive (Acre-feet) 29-year 21-year 11-year period period period Measured during part of period 960 1,240 1,000 Estimated, originating in Directly tributary hills 460 480 470 Precipitation on valley and folded land 1,100 1,140 1,110 Total 2,520 2,860 2,580 150 DIVISION OF WATER RESOURCES Overdraft If the 21-year period were assumed to be the cycle of long-time mean supply the estimated overdraft would be 20 acre-feet, as derived in Table 88. If the 29-year period were assumed to be the cycle, annual overdraft would be 1,040 acre-feet. The difference is due primarily to difference in estimated precipitation during the two cycles. Fifty-three year mean precipitation is greater than that in the 29-year period, and less than the 21-year average. Therefore, annual overdraft is estimated to be the average of the two values, or 530 acre-feet. TABLE 88. ESTIMATED ANNUAL OVERDRAFT IN LA HABRA BASIN UNDER PRESENT CONDITIONS ASSUMING THE 21 -YEAR PERIOD, 1922-23 TO 1942-43, INCLUSIVE, TO BE ONE OF LONG-TIME MEAN SUPPLY (Acre-feet) Estimated Actual long-time 11-year yiean annual lase under period present average Differ conditions annual ence Average annual drop in storage during base period Items tending to increase the drop Consumptive use 42,650 42,670 —20 Export 3,440 2,940 500 Surface outflow 2,860 2,580 280 Subtotal to be added Items tending to decrease the drop Precipitation 32,960 31,980 980 Surface inflow 2,760 2,680 80 Import 18,830 18,400 ' 480 Subtotal to be subtracted Overdraft 750 760 1,490 20 Subsurface Outfiotv Assuming that all items involved have been correctly evaluated, sub- surface outflow during the 11-year base period must, in accordance with principles set forth in Chapter V, have averaged 5,620 acre-feet annually, as derived in Table 89. SOUTH COASTAL BASIN INVESTIGATION 151 TABLE 89. ESTIMATED AVERAGE ANNUAL SUBSURFACE OUTFLOW FROM LA HABRA BASIN DURING THE 11-YEAR PERIOD, 1927-28 TO 1937-3 8, INCLUSIVE Acre-feet Water entering basin Precipitation 31,980 Surface inflow 2,680 Import 18,400 Water coming from storage in basin 750 Subtotal 53,810 Water leaving basin on surface Surface outflow 2,580 Exported water — — 1,520 Exported sewage 1,420 Consumptive use 42,670 Subtotal 48,190 Subsurface Outflow — to Montebello Forebay Area 5,620 LOWER LOS ANGELES AND SAN GABRIEL RIVERS AREA Hollywood Basin (3 2) Los Angeles Forebay Area (3 3a) Montebello Forebay Area (3 3b) Central Coastal Plain Pressure Area (33e) Los Angeles Narrows Basin (36) There is no physical barrier to movement of ground water from Los Angeles Narrows Basin into Los Angeles Forebay Area, nor to movement from Los Angeles and Montebello Forebay areas into the Pressure Area, so the four are treated together. Hollywood Basin is served largely with imported water, and so great a part of this import is again exported for use in other portions of the City of Los Angeles that a separate estimate of excess supply in that basin is not only extremely difficult, but also serves no very useful purpose. For this reason Hollywood Basin is included as a component of Lower Los Angeles and San Gabriel Rivers area. Lower Los Angeles and San Gabriel Rivers area is located in the north central portion of the coastal plain, and covers about 288 square miles. It is bounded on the north by Santa Monica Mountains and San Fernando Basin, on the northeast by San Rafael Hills and Pasadena subarea, on the east by Merced Hills, Main San Gabriel Basin and La Habra Basin, on the southeast by East Coastal Plain Pressure Area, and on the south and west by Inglewood Fault Zone. Los Angeles Narrows Basin, covering about 13 square miles, consists largely of irregular narrow valleys between hills, with slopes varying greatly both in direction and steepness. Elevations range from 280 feet above sea level at the southerly boundary near Los Angeles River, to 700 feet along Arroyo Seco in the City of Pasadena. The channel of Los Angeles River is incised some 25 feet below the level of adjacent valley lands. Hollywood Basin, with an area of about 15 square miles, is more regular. In the easterly three-quarters the slope to the south varies from 152 DIVISION OF WATER RESOURCES about 60 to 700 feet per mile. In the westerly portion it is to the south- east, and averages about 150 feet per mile. Topography of the south central portion of the basin is smooth, with relatively flat slope to the south. Elevations vary from 155 feet above sea level east of Beverh^ Hills, to 600 feet above north of Hollywood. Topography of Los Angeles Forebay area, covering about 47 square miles, is somewhat irregular and rolling in the northerly and easterly portions, but is more uniform in the central and southerly parts. Slopes are generally to the south and southwest, and range from 20 to more than 200 feet per mile. Elevation in the vicinity of the City of South Gate is 120 feet above sea level, while at the northeasterly extremity of the basin it is 500 feet. In the lower portion of the Forebay area, the Los Angeles River bed is slightly below adjacent land surface. Both Rio Hondo and San Gabriel River traverse Montebello Fore- bay area. Topography is only slightly irregular throughout the central and southerly parts of the basin, but is decidedly irregular and rough in the folded area occupying the north central part. Slope is generally to the south and southwest, and varies from 15 to 225 or more feet per mile for valley lands. In the folded area slopes are extremely variable both in direction and magnitude. Elevations range from 105 feet to 325 feet above sea level in the vallev, and to 630 feet above in the folded area. Central Coastal Plain Pressure area extends in a general north- westerly-southeasterly direction, and covers 172 square miles. Topog- raph}^ is irregular, with slopes varying both in magnitude and direction. Elevation near the City of Long Beach is sea level, while at the easterly extremity of the pressure area an elevation of 300 feet above sea level is reached. In Hollywood Basin soils range from heavy Montezuma clay adobe, through Chino and Ramona clays and loams, to light Hanford loams and sand}^ loams near the base of Santa Monica Mountains. In the remainder of the nonpressure portion of the area soils are principally lighter members of the Hanford and Ramona series, with the former predominating. Approximately two-thirds of the pressure area is covered by soils of the Hanford and Tujunga series, and the remainder by those of the less pervious Chino Series. These soils finger into one another throughout the pressure area, with Chino soils being somewhat more extensive in the lower portion. Municipal development occupies virtually all of Hollywood Basin and Los Angeles Forebay area, and a very large part of the Los Angeles Narrows Basin, and of the pressure area west of Los Angeles River. In Montebello Forebay area, and in the pressure area east of Los Angeles River there is considerable municipal development, but it does not dom- inate the area. In Montebello Forebay area roughly two-thirds of agri- cultural land is devoted to citrus, while in the pressure area garden and field crops and alfalfa predominate. Most unirrigated land is covered by grass and weeds. The local water supply, utilized to some extent by gravity diver- sions but more through pumping from ground water, originates in precipitation on valley lands, inflow from 8,180 acres of mountains and 25,160 acres of hills directly tributary to the nonpressure portion of the area, surface and subsurface inflow from San Fernando Valley area, Main San Gabriel and La Habra Basins, and surface inflow from SOUTH COASTAL BASIN INVESTIGATION 153 Western Unit of Raymond Basin Area. Water is imported in large amount, both for municipal use and for irrigation. A relatively large part of the surface inflow to and precipitation on the nonpressure portion of the area flows out onto the pressure area, from whence it wastes to the ocean, mainly in Los Angeles and San Gabriel Rivers and Ballona Creek. Some water flows out underground across Inglewood Fault, which forms the lower southwesterly boundary of the pressure area. AVhile there is no continuous barrier between East and Central Coastal Plain pressure areas, significant movement of ground water in either direction would require pronounced changes in the present pattern of pumping. Water and sewage are exported in large amounts. The pressure area is characterized by virtually continuous beds of impervious clays, which lie between the ground surface and the main aquifers from which ground water is pumped for use. Because of this virtually all percolation from stream flow, precipitation and irrigation water in this area remains perched near the surface. The usable supply, pumped from deeper strata, virtually all originates in underfloAV from Los Angeles and Montebello Forebay areas and La Habra Basin. While recent studies indicate that small storage changes occur in the confined strata, by far the greater part of the regulation of supply to the pressure area and to the area as a whole is through storage changes in the non- pressure basins and forebay areas. For the area as a whole, present demand is greater than average supply under present conditions, so an overdraft of considerable magni- tude exists. In estimating the amount of this overdraft, significant items are change in storage, precipitation on, and surface inflow and import to the nonpressure portion of the area; surface outflow, consumptive use and export leaving the nonpressure portion of the area ; and extractions from the pressure area. Evaluation of each of these items* follows. Inflotv to Nonpressure Portion of Area Estimated annual surface inflow averages 168,910 acre-feet, 141,130 acre-feet and 123,360 acre-feet in the 29-, 21- and 11-year periods, respectively, as derived in Table 90^. About 21 percent of 8,180 acres of mountains, and 51 percent of 25,160 acres of hills, directly tributary to the nonpressure portion of the area are classified as having domestic or industrial culture. The acre- age so developed is increasing (See Table 92). It is estimatedf that 25 percent of the precipitation on these developed portions of mountain and hill area, 10 percent of that on remaining mountain area, and 9 percent of that on remaining hill area runs off. Surface inflow to Los Angeles Narrows Basin includes all surface outflow from San Fernando Valley Area, and that in Arroj^o Seco from Western Unit of Raymond Basin Area. That to Montebello Forebav area includes all surface outflow from Main San Gabriel Basin, and a very small part of that from La Habra Basin. Subsurface inflow to Los Angeles Narrows Basin includes all sub- surface outflow from San Fernando Valley Area, estimated to be 7,110 acre-feet annually. That to Montebello Forebay Area, in addition to • Values of change In storage and precipitation are presented in Tables 5 and 7. " t Eleven-year average runoff values at Stations 390, 1281, 1459 and 1525, are used as basis for estimates of runoff factors. 154 DIVISION OF WATER RESOURCES 23,280 acre-feet from Main San Gabriel Basin, is assumed to include all subsurface outflow from La Habra Basin, estimated to be 5,620 acre- feet annually. Total annual subsurface inflow to Montebello Fore- bay Area is then 28,900 acre-feet, while to Lower Los Angeles and San Gabriel Eivers Area as a whole, it is 36,010 acre-feet. TABLE 90. SURFACE INFLOW TO NONPRESSURE PORTION OF LOWER LOS ANGELES AND SAN GABRIEL RIVERS AREA Average annual for 29-year period, 1904-05 to 1932-33, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 1 1 -year period, 1927-28 to 1937-38, inclusive (Acre-feet) 29-year 21-year 11-year period period period From directly tributary mountains Estimated " 1,580 From directly tributary hills Estimated "^ 6,090 From other basins San Fernando Valley Area 24,450 Raymond Basin Area 6,180 Main San Gabriel 130,530 La Habra ^ 80 Total 168,910 141,130 123,360 1,650 1,590 6,330 6,020 22.040 4,820 106,200 90 20,360 2,620 92.680 90 3 Includes a relatively small amount of underflow. Also includes precipitation on distributing reservoirs. Import to Nonpressure Portion of Area In Table 91 estimated imports to the nonpressure portion of the area for each j^ear since 1927-28 are presented. There is no import of sewage. Water is imported from San Fernando Valley Area, Main San Gabriel and La Habra Basins, West Coastal Plain, Western Unit of Raymond Basin Area, Central Coastal Plain Pressilre Area and from Colorado River. During the 11-year period, an annual averagie of 140,310 acre- feet of water was imported. Average annual import from Main San Gabriel and La Habra Basins under present conditions is estimated to equal the historic average for the four-year period, 1941-42 to 1944-45, inclusive. For that from other sources, the 1944-45 value is assumed to represent the average annual under present conditions. Estimated total average annual import under present conditions is 214,930 acre-feet. TABLE 91. IMPORT TO NONPRESSURE PORTION OF LOWER LOS ANGELES AND SAN GABRIEL RIVERS AREA Year Acre-feet Year Acre-feet Year Acre-feet 1927-28 128,180 1933-34 132.520 1939-40 166,130 1928-29 131,020 1934-35 128,790 1940-41 164,580 1929-30 136,230 1935-36 149,980 1941-42 169,050 19.30-31 143.720 1936-37 155,640 1942-43 ,_ 185,560 1931-32 140,710 1937-38 160,450 1943-44 203,140 1932-33 141,120 1938-39 168,070 1944-45 215,260 SOUTH COASTAL BASIN INVESTIGATION 155 Consutnptive Use in Nonpressure Portion of Area 111 Table 92 estimated values of average annual consumptive use in the nonpressure portion of Lower Los Angeles and San Gabriel Rivers Area, based on culture surveys conducted by the Division of Water Resources in 1932 and 1942, are presented. Unit consumptive use is dis- cussed in Chapter V. In Hollywood and Los Angeles Narrows Basins and Los Angeles Forebay Area expanding municipal development occupies 94 percent of valley and folded lands, and 49 percent of tributary mountain and hill area. Domestic and industrial culture in Montebello Forebay Area occupies about 26 percent of valley lands, while 46 percent is devoted to irrigated agriculture of which nearly two-thirds is in citrus. There are small areas of water-loving natural vegetation along river channels in and below Whittier Narrows. Of the relatively small area of unused lands in the area as a whole, the greater part is lying fallow and is covered by grass and weeds. TABLE 92. ESTIMATED AVERAGE ANNUAL CONSUMPTIVE USE IN NON- PRESSURE PORTION OF LOWER LOS ANGELES AND SAN GABRIEL RIVERS AREA Unit con- sumptive 1932 1942 Type of culture use, feet Acres Acre-feet Acres Acre-feet Vallev and folded area Garden and field 1.1 3,308 3,639 3.408 8,749 Avocado and citrus 1.9 6,902 13,114 7,413 14,085 Deciduous 1.7 2,441 4,150 837 1,423 Alfalfa 2.5 810 2,025 680 1,700 Irrigated grass 2.5 940 2,350 995 2,487 Natural water-loving vegetation___ 4.0 193 772 193 772 Domestic and industrial'' 1.4 5,333 7,466 7,046 9,864 Domestic and industrial" 1.0 44,375 44,375 44,914 44,914 Unirrigated 10,104 8,920 29-year period 0.9 8,020 21-year period 0.919 8,197 11-year period 0.906 9,154 Subtotal 74,406 74,406 29-year period 87,022 21-year period 87,191 11-year period 87,045 Hill and mountain area Garden and field 0.2 «= 16 3 16 3 Avocado and citrus 1.0"= 71 71 71 71 Deciduous 0.8*= 10 8 10 8 Evaporation from distributing reservoirs 3.2<» 179 573 179 573 Irrigated grass 1.5 <= 811 1,216 866 1,299 Domestic and industrial 0.5 <= 43 22 67 34 Domestic and industrial "___: 0.1" 13,829 1,383 14,409 1,441 Subtotal 14,959 3,276 15,618 3,429 Grand total — 89,365 90,024 29-year period 90,451 21-year period 90,620 11-year period — *- 90,321 » Montebello Forebay Area. *> Hollywood and Los Angeles Narrows Basins and Los Angeles Forebay Area. <= Difference between irrigated culture and natural vegetation. * Difference between evaporation from reservoirs and consumptive use of natural vegetation, 156 DIVISION OF WATER RESOURCES Export From Nonpressiire Portion of Area In Table 93 estimated exports from the nonpressure portion of Lower Los Angeles and San Gabriel Rivers Area for each year since 1927-28 are presented. Water is exported to Main San Gabriel and La Habra Basins. West Coastal Plain, San Fernando Valley Area and Central Coastal Plain Pressure Area, while sewage goes to the ocean, to Main San Gabriel Basin, and to Central Coastal Plain Pressure Area. Export for use includes both gravity and pumped water. During the 11-year period, an annual average of 43,730 acre-feet of water, and 84,850 acre-feet of sewage was exported, a total of 128,580 acre-feet. Estimated average annual export of water under present conditions is 74,570 acre-feet, and of sewage 120,680 acre-feet, a total of 195,250 acre-feet. Average annual export of water to Main San Gabriel and La Habra Basins from Montebello Forebay Area under present conditions is estim.ated to equal the historic average for the four-year period, 1941-42 to 1944-45, inclusive. For the remainder of the export, the 1944-45 value is assumed to represent the average under present conditions. TABLE 93. EXPORT FROM NONPRESSURE PORTION OF LOWER LOS ANGELES AND SAN GABRIEL RIVERS AREA (Acre-feet) Year Water Seicage Year Water Sewage 1927-28 36,560 70,440 1936-37— 52,230 95,920 1928-29 39,730 80,500 1937-38 53,720 98,720 1929-30 40,960 85,250 1938-39 56,030 97,270 19.30-31 42,390 85,340 1939-40 55,300 99,700 ] 931-32 42,750 85,630 1940-41 55,170 109,470 1932-33 41,590 83.680 1941-42 58,870 104,600 1933-34 40,510 75,350 1942-48 65,900 108,900 1934-35 38,940 85.200 1943-44 70,520 125,650 19.35-36 51,600 87,280 1944-45 74,950 120,680 Surface Outflow From Nonpressure Portion of Area Surface outflow from Los Angeles Foreba}^ Area, and Hollywood and Los Angeles Narrows Basins includes part of the inflow from directly tributary mountains and hills, runoff originating in precipitation on val- ley lands, and inflow from San Fernando Valley Area, and from Western Unit of Raymond Basin Area in Arroyo Seco. Virtually all inflow from directly tributary mountains and hills, and valley runoff, is picked up on paved streets or in storm drains and carried directly to main drainage channels. The channel of Los Angeles River is paved throughout nearly the entire reach within the nonpressure portion of the area. Estimated surface outflow from this portion of the area includes 95 percent of the inflow from tributarv hills and mountains, all surface inflow from other basins, and percentages of precipitation on various portions of overlying valley ranging from 20 percent on 3,480 acres, through 25 percent on 14,600 acres, and 30 percent on 21,190 acres, to 50 percent on 8,440 acres. Nearly all surface outflow from Montebello Forebay Area is in Rio Hondo which has been measured at Station 1535 since March, 1928, and in San Gabriel River which has been measured at Station 1008 since February 6, 1928. Based on these measurements, 11-year average annual SOUTH COASTAL BASIN INVESTIGATION 157 outflow in the two rivers is estimated to be 34,790 acre-feet. In addition, unmeasured outflow is estimated to include 90 percent of inflow from 1,290 acres of hills, and 25 percent of precipitation on 4,960 acres and 5 percent of that on 9,800 acres of valley and folded land, or 2,280 acre- feet annually during the 11-year period. Total average annual surface outflow during this period is then 37,070 acre-feet. Of this total, it is estimated that 20,780 acre-feet originated in mountain runoff from San Gabriel Canyon, and from Fish and Rogers Creeks, and that 16,290 acre-feet came from other sources. Water flows out of Montebello Forebay Area on the surface for two reasons, (1) because the rate of surface inflow is greater than the perco- lating capacity of channels and spreading grounds in the area, and (2) because the underground storage capacity has not been sufficiently developed to completely regulate the inflow. In estimating the long-time mean annual outflow for the first reason, it is arbitrarily assumed that the virtually unregulated outflow of water originating in sources other than the mountains above the mouth of San Gabriel Canyon is proportional to precipitation on the tributary area. Under this assumption present outflow from these sources averages 16,650 acre-feet annually for both the 29- and 21-year periods. Long-time mean annual outflow of water originating in San Gabriel Canyon, including that in Fish and Rogers Creeks, depends upon the degree of regulation achieved in the several upstream flood control reservoirs, and the effect on percolation of this regulation and extensive spreading both above and below Whittier Narrows. Under a plan of reservoir and spreading ground operation which reconciles as well as niSiy be the conflicting interests of water conservation, flood control and the avoidance of a too high water table in San Gabriel Valley, and which is in reasonable agreement with plans of Los Angeles County Flood Control District, estimated outflow originating in this source averages 9,150 acre-feet annually in the 29-year period, and 6,850 acre-feet in the 21-year period. Complete regulation of the remaining supply to Montebello Forebay Area, in order that there be no outflow for the second reason stated above, requires that extractions during the dry period of the cycle draw the water table down sufficiently to provide capacity enough to store not only the excess originating above the mouth of San Gabriel Canyon during the period, but also the excess rising water, which constitutes a large part of the inflow at the Narrows. Under the adopted plan of operation, overall fluctuation of the water table at Wells C-294 and C-294a will be somewhat greater than the historic depicted on Plate 11, and the variations in amount of rising water correspondingly greater than those indicated on Plate 24. It is estimated that complete regulation under the plan requires an overall fluctuation in Montebello Forebay Area of about 150 feet over the 29-year period and 110 feet over the 21-5"ear period. Estimated total surface outflow from Montebello Forebay Area with these fluctuations thus averages 25,800 and 23,500 acre-feet in the two periods. With water table fluctuation in the forebay area limited to 100 feet, estimated average annual surface outflow is increased to 43,180 acre-feet and 25,580 acre-feet in the 29- and 21-year periods, respectively. The historic range of fluctuation is about 50 feet, and just how far below sea level the piezometric surface in the pressure area near the 158 DWISION OF WATER RESOURCES ocean must be drawn down in order to achieve a 100-foot fluctuation in the forebay area with present pattern of pumping, is not known. "With extractions near the ocean sufficiently reduced, and those in and near the forebay area correspondingly increased it could be above sea level at all time. TABLE 94. SURFACE OUTFLOW FROM NONPRESSURE PORTION OF LOWER LOS ANGELES AND SAN GABRIEL RIVERS AREA Average annual for 29-year period, 1904-05 to 1932-33, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38, inclusive (Acre-feet) 29-year 21-year 11-year period period period Los Angeles Forebay Area, and Hollywood and Los Angeles Narrows Basins Estimated, originating in Surface inflow from San Fernando Valley Area__ 24,450 22,040 20,360 Surface inflow from Western Unit of Raymond Basin Area 6,180 4,820 2,620 Inflow from directly tributary mountains and hills 6,600 6,870 6,540 Precipitation on valley and folded land 19,180 19,890 19,330 Subtotal 56,410 53,620 48,850 Montebello Forebay Area 43,180 25,580 37,070 Total 99,590 79,200 85,920 Extractions From Coastal Plain Pressure Area It is estimated that present annual extractions from the pressure area are 34,430 acre-feet greater than the average during the 11-year period, as derived in Table 95. About 56 percent of the total production, including that of most of the larger producers whose 1944-45 extractions were significantly different from the average for the 11-year period, has been measured. To estimate increase in unmeasured extractions, acreages of each type of culture lying outside of areas served by measured extrac- tions, as determined by surveys conducted by the Division of Water Resources in 1932 and 1942, are used, together with estimated average values of duty for each culture type. By far the greater part of the change since 1942 has been in the domestic and industrial type, and 25 percent of the increase in estimated service to that type between 1932 and 1942 is added to allow for this change. Pumped water has been sub- stituted for 310 acre-feet imported annually during the 11-year period. SOUTH COASTAL BASIN INVESTIGATION 159 TABLE 95. ESTIMATED DIFFERENCE BETWEEN II -YEAR AVERAGE AND PRESENT ANNUAL EXTRACTIONS FROM CENTRAL COASTAL PLAIN PRESSURE AREA 11-year average acre-feet 19U-45 acre-feet Increase, acre-feet Measured extractions Municipalities 28,920 33,720 Water districts and companies 16,120 . 33,510 Increase in measured extractions 4,800 17,390 22,190 Acres served Idh 1942 Increase Unmeasured extractions Garden and field 17,520 15,740 —1,780 Avocado and citrus 1,640 1,830 190 Deciduous 1,200 720 -^80 Alfalfa 3,420 4,390 970 Irrigated grass 550 910 360 Domestic and industrial 9,400 15,400 6,000 Increase in use since 1942 Decrease in import Duty, feet 1.0 1.5 1.0 2.0 2.0 1.5 -1,780 280 -^80 1,940 720 9,000 2,250 310 Increase in unmeasured extractions 12,240 Total increase in extractions 34,430 Overdraft Assuming that the 21-year pericrd represents a cycle of long-time mean supply, that reservoirs and spreading grounds are operated accord- ing to the plan herein adopted, and that fluctuations of the water table in Monebello Forebay Area are limited to a range of 100 feet, estimated annual overdraft is 12,270 acre-feet, as derived in Table 96. If 29-year mean values are substituted, the derived value is 8,890 acre-feet. When outfall sewers to the ocean are completed for County Sanita- tion Districts 15 and 16 in San Gabriel Valley, inflow to Montebello Forebay Area will be decreased, and overdraft in Lower Los Angeles and San Gabriel Rivers Area increased by the amount of the sewage outflow. On the other hand, increased demand within the service area of the City of Los Angeles will not add to the overdraft unless extrac- tions from the ground water of the Coastal Plain by the city are increased in lieu of utilizing a portion of the Mono Basin-Owens Valley aqueduct water herein considered as excess in San Fernando Valley Area, or increasing import from Colorado River. 160 DIVISION OF WATER RESOURCES TABLE 96. ESTIMATED ANNUAL OVERDRAFT IN LOWER LOS ANGELES AND SAN GABRIEL RIVERS AREA UNDER PRESENT CONDITIONS ASSUMING THE 21-YEAR PERIOD, 1922-23 TO 1942-43, INCLUSIVE, TO BE ONE OF LONG-TIME MEAN SUPPLY (Acre-jeet) Estimated Actual long-time 11-year mean annual base under period present average Differ conditions annual ence Average annual drop in storage during base period 12,900 * Items tending to increase the drop Nonpressure portion of area Consumptive use 90,620 90,320 300 Surface outflow 79,200 85,920 —6,720 Export 195,250 128,580 66,670 Pressure area Extractions 34,430 Subtotal to be added 94,680 Items tending to decrease the drop Nonpressure portion of area Precipitation 98,500 95,580 2,920 Surface inflow 141,130 123,360 17,770 Import 214,930 140,310 74,620 Subtotal to be subtracted 95,310 Overdraft 12,270 " Includes 2,580 acre-feet in pressure area. CLAREMONT HEIGHTS BASIN (17) Claremont Heights Basin is located below the mouth of San Antonio Canyon, on either side of the Los Angeles-San Bernardino County boundary, in the northwest portion of Upper Santa Ana Valley, and covers about eight square miles. It is bounded on the southwest by Live Oak Basin, on the northwest and north by San Gabriel Mountains, on the southeast by Chino Basin, and on the south b}^ Pomona Basin. Topography is typical of the upper portion of cones built up by larger streams, exhibiting no. large irregularities but cut by innumerable chan- nels. Slope averages 200 feet per mile in a direction generally a little west of south. Elevations in the valley range from 1,300 to 2,100 feet above sea level. Soils are mostly lighter and rockier members of the Hanford and Tujunga series, and are very receptive of moisture. Stream channels are poorly defined and percolation opportunity is large. Agri- cultural development covers about 36 percent of the area, the rest being still in its natural state, except for a small acreage of domestic culture. The local water supply, utilized in part through diversion from surface streams, and in part through pumping from ground water, origi- nates in precipitation on the valley, and inflow from 19,780 acres of mountains directly tributary to the basin. A very small amount of water is imported. SOUTH COASTAL BASIN INVESTIGATION 161 A relatively small part of the surface inflow and precipitation flows out into Chino Basin, together with considerable underflow into Chino, Live Oak and Pomona Basins, and water is exported in relatively large amount to Chino, Pomona and Cucamonga Basins. In Claremont Heights Basin, long-time mean annual net supply under present conditions is slightly less than present annual demand if the 21-year period is assumed to represent the long-time mean cycle of supply and somewhat greater if the 32-year cycle is used, indicating an overdraft under one assumption and an excess under the other. Evaluation of items required* to estimate the amount of overdraft or excess follows. Inflow Estimated annual surface inflow averages 24,630 acre-feet, 23,260 acre-feet and 22,260 acre-feet in the 32-, 21- and 11-year periods, respec- tively, as derived in Table 97. Annual inflow from a portion of the directly tributary mountain area was measur-ed in San Antonio Creek, at Stations 5628 and 5638 during the entire period. The estimate of 32-year mean annual inflow from 8,990 acres of mountains directly tributary to the basin, and downstream from gaging stations at which above inflow was measured is based on the assumption that, if water is available, average consumptive use on the mountain area is 18 inches. Average inflow from the greater part of mountains during the 11-year base period is estimated to be 0.91 times the 32-year mean, this being the ratio between 11- and 32-year mean discharge of San Antonio Creek. For mountain areas in the westerly portion, how- ever, the ratio is that for San Gabriel Eiver, i.e. 0.81. Corresponding ratios for the 21-year period are 0.95 and 0.86. Subsurface inflow, other than that indicated by note in Table 97, is negligible. TABLE 97. SURFACE INFLOW TO CLAREMONT HEIGHTS BASIN Average annual for 32-year period, 1904-05 to 193 5-36, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-3 8 inclusive (Acre-feet) 32-year 21-year 11-year period period period From directly tributary mountains Measured during entire period 17,410 16,510 15,820 Estimated"^ 7,220 6,750 6,440 Total 24,630 23,260 22,260 a Includes a relati\ely small amount of underflow. Iftiport In Table 98 estimated values of imports of water for each year since 1927-28 are presented. There is no import of sewage. During the 11- year period an annual average of 100 acre-feet of water was imported from Pomona Basin. * Values of change in storage and precipitation, also required, are presented m Tables 5 and 7. 11—71061 162 DIVISION OF WATER RESOURCES Estimated average annual import under present conditions is 80 acre-feet, equal to the average for the seven-year period, 1938-39 to 1944-45, inclusive. TABLE 9S. IMPORT TO CLAREMONT HEIGHTS BASIN Year Acre- feet Year Acre- feet Year Acre- feet 1927-28. 1928-29. 1929-30. 1930-31. 1931-32. 1932-33. 1933-34 10 1939-40 280 1934-35 30 1940-41 20 1935-36 120 1941-42 100 1936-37 140 1942-43 340 1937-38 170 1943-44 250 1938-39 260 1944-45 Consuffiptive Use In Table 99 estimates of consumptive use based on culture surveys conducted by the Division of Water Resources in 1932 and 1942 are presented. Unit consumptive use is discussed in Chapter V. The area occupied by domestic development is small and there are no industries. A large part of the unused land is included in the wash of San Antonio Creek and adjoining spreading grounds. These are largely covered by brush. TABLE 99. ESTIMATED AVERAGE ANNUAL CONSUMPTIVE USE IN CLAREMONT HEIGHTS BASIN Type of culture Unit con- sumptive use, feet 1932 Acres Acre-feet 1942 Acres Acre-feet Valley area Garden and field 1.3 15 Avocado and citrus 2.0 1,557 Irrigated grass 3.0 40 Domestic and industrial 1.5 142 Unirrigated 3,378 32-year period 1.7 21-year period 1.692 11-year period 1.669 Total 5,132 32-year period 21-year period 11-year period 20 3,114 120 213 5,638 9,105 5 1,787 35 142 3,163 5,132 6 3,574 105 213 5,377 5,352 9,275 9,250 Export In Table 100 estimated values of exports of water for each year since 1927-28 are presented. There is no sewage outflow. Water from both gravity and pumped sources is exported to Chino, Live Oak, Pomona and Cucamonga Basins. During the 11-year period, an annual average of 14,200 acre-feet of water was exported. The amount of gravity water exported depends to some extent upon the amount available. Average annual export of San Antonio Creek water to Cucamonga Basin under present conditions has been discussed SOUTH COASTAL BASIN INVESTIGATION 163 ill connection with import to that basin. Export of purely gravity water to Pomona Basin was measured throughout the 21-year period. Present average annual export of purely pumped water is assumed to equal its average for the four year period, 1941-42 to 1944-45, inclusive. Present export of combined pumped and gravity water to Chino Basin by a single company is estimated to equal the company's four-year average annual import to Chino Basin from both Claremont Heights and Cucamonga Basins, minus its long time average annual import under present condi- tions from Cucamonga Basin alone. Estimated total average annual export under present conditions is 17,940 acre-feet. TABLE 100. EXPORT FROM CLAREMONT HEIGHTS BASIN Year Acre-feet Year Acre-feet Year Acre-feet 1927-28 12,510 1933-34 8,920 1939-40 17,870 1928-29 11,290 1984-35 15,430 1940-41 20,570 3929-30 12,920 1935-36 15,920 1941-42 17,710 1930-31 10,560 1936-37 19,880 1942-43 19,650 1931-32 15,770 1937-38 20,780 1943-44 23,550 1932-33 12,180 1938-39 16,600 1944-45 22,560 Surface Outflow Outflow on the surface includes part of the inflow from directly tributary mountains and runoff originating in precipitation on the over- lying valley. It is estimated to average 2,110 acre-feet, 2,140 acre-feet, and 3,120 acre-feet annually during the 32-, 21- and 11-year periods, respectively, as derived in Table 101. Inflow of mountain water is mostly in San Antonio Creek, which flows about four miles across the basin in unpaved channels. Large spreading grounds augment natural percolation from this stream, and it is only in time of high water that any flow leaves the basin. A record of daily discharges of San Antonio Creek at Stations 5628 and 5638 since October 1, 1904, is available. Runoff from a considerable area of mountains draining into the creek below the station is estimated to be 76 percent of the discharge at the gaging station on days of high flow. Daily discharges at the canyon mouth are estimated on this basis for years prior to 1931-32. After that time a record is available at Station 4514, near that point. Of the flow at the canyon mouth, 30 second-feet is assumed to be diverted for use when available, and the remainder up to 330 second-feet, diverted to spreading at all times except during extreme flood periods. During the first 10 years of the 11-year period no discharge was sufficiently great to reach the lower boundary of the basin. In 1937-38 the spreading grounds were so damaged that, out of a total runoff of 42,300 acre-feet at Station 4514, only about 16,800 acre-feet percolated or was spread, and 25,500 acre-feet is esti- mated to have flowed out. To estimate outflow in the creek during 32- and 21-year periods, estimated daily discharges below the spreading grounds and a percola- tion curve which results in complete percolation up to 23 second-feet, are used. In estimating outflow under present conditions, possible effects of proposed flood control works on San Antonio Wash are not considered. Any reduction in natural percolation due to lining channels can be offset by increased spreading. 164 DIVISION OF WATER RESOURCES It is assumed that all runoff from mountains above Thompson Creek Dam percolates in the reservoir, or is spread below the dam. It is estimated that 90 percent of inflow from about 500 acres of mountains tributary to Thompson Creek below the dam, 5 percent of precipitation on 340 acres of valley land in the westerly portion of the area, 2 percent of precipitation on about 4,370 acres of remaining valley land, and 90 per- cent of inflow from 1,020 acres of mountain area in the easterly portion of the basin which is not tributarv to San Antonio Wash runs out. TABLE 101. SURFACE OUTFLOW FROM CLAREMONT HEIGHTS BASIN Average annual for 32-year period, 1904-05 to 193 5-36, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-3 8, inclusive (Acre-feet) 32-year 21-year 11-year period period period Estimated, originating in San Antonio Creek 1,220 1,300 2,320 Directly tributary mountains 700 650 620 Precipitation on valley land 190 190 180 Total 2,110 2,140 3,120 Overdraft Assuming that the 21-year period is the cycle of long-time mean supply, estimated annual overdraft is 1,420 acre-feet, as derived in Table 102. If 32-year mean values are substituted in the table an annual excess of 50 acre-feet is indicated. TABLE 102. ESTIMATED ANNUAL OVERDRAFT IN CLAREMONT HEIGHTS BASIN UNDER PRESENT CONDITIONS ASSUMING THE 21 -YEAR PERIOD, 1922-23 TO 1942-43, INCLUSIVE, TO BE ONE OF LONG-TIME MEAN SUPPLY (Acre-feet) Estimated Actual lo'ng-iime 11 -year mean annual iase under period present average Differ conditions annual ence Average annual rise in storage during base period 270 Items tending to increase the rise Precipitation 9,390 9,150 240 Surface inflow 23,260 22,260 1,000 Import 80 100 —20 Subtotal to be added 1,220 Items tending to decrease the rise Consumptive use 9,250 9,100 150 Surface outflow 2,140 3,120 —980 Export 17,940 14,200 3,740 Subtotal to be subtracted 2,910 Overdraft 1,420 SOUTH COASTAL BASIN INVESTIGATION 165 Subsurface Outflow Assuming that all items involved have been correctly evaluated, subsurface outflow during the 11-year base period, must, in accordance with principles set forth in Chapter V, have averaged 4,820 acre-feet annually, as derived in Table 103. Its distribution between the three basins is arbitrary, based upon requirements in those basins and behavior of wells therein. TABLE 103. ESTIMATED AVERAGE ANNUAL SUBSURFACE OUTFLOW FROM CLAREMONT HEIGHTS BASIN DURING THE ll-YEAR PERIOD, 1927-28 TO 1937-38, INCLUSIVE Acre-jeet Water entering basin Precipitation 9,150 Surface inflow 22,260 Import 100 Water coming from storage in basin — 270 Total 31,240 Water leaving basin on surface Surface outflow 3,120 Export 14,200 Consumptive use 9,100 Total 26,420 Subsurface Outflow 4,820 To Live Oak Basin 3,320 To Pomona Basin 1,000 To Chino Basin 500 LIVE OAK BASIN (18) Live Oak Basin is located in the extreme northwest corner of Upper Santa Ana Valley, and covers about 3.1 square miles. It is bounded on the northwest by San Dimas Basin, on the north by San Gabriel Moun- tains, on the northeast by Claremont Heights Basin, and on the south by Pomona Basin. Topography is irregular, particularly in its northern part where the alluvium extends steeply upward into the mountains. In the lower portions, west of Thompson Creek, slope varies from 60 to 175 feet per mile, and is to the west and southwest. East of that stream the slope averages about 125 feet per mile in a direction a little west of south. Here the topography is relatively smooth. Elevations in the valley range from 1,000 to 1,350 feet above sea level. The alluvium extends to elevation 1,600 in the mountains. Soils covering this basin are mostly lighter members of the Hanford series, with a considerable area of some- what less pervious Kamona loam in and below the canyon mouth. Only about 2 percent of the area is covered by culture of a municipal type, about 82 percent is devoted to agriculture, and about 16 percent is in a more or less natural state. The local water supply, utilized to a minor extent through diversion from surface streams, but more through pumping from ground water, originates in precipitation on the valley, inflow from 2,000 acres of 166 DIVISION- OF WATER RESOURCES mountains directly tributary to the basin, and both subsurface and surface inflow from Claremont Heights Basin, the greater part of the last named as flood flow in Thompson Creek. Imported water provides a relatively large addition to the supply. A considerable part of surface inflow and precipitation flows out into Pomona Basin, together with material underflow, and water is exported in relatively large amount to San Dimas and Pomona Basins. In this basin, long-time mean annual net supply, under present con- ditions is a little greater than present annual demand, so a small excess exists. Evaluation of items required * to estimate its amount follows. Inflow Estimated annual surface inflow averages 430 acre-feet, 370 acre- feet, and 310 acre-feet in the 32-, 21- and 11-year periods, respectively, as derived in Table 104. Annual inflow from a portion of the directly tributary mountain area was measured in Live Oak Creek at Station 4457 for several years. Average values for all three periods are derived by comparison with San Dimas Creek. The estimate of 32-vear mean annual inflow from 460 acres of mountains directly tributary to the basin, and downstream from the gaging station at which above inflow was measured, is based on the assumption that average consumptive use on mountain area is 22 inches, runoff however never being less than 7 percent of the precipitation. The 11-year value is estimated to be 0.81 times the 32-year mean, this being the ratio between 11- and 32-year mean discharge of San Gabriel River. The corresponding ratio for the 21-year period is 0.86. Surface outflow from a small area at the westerly edge of Claremont Heights Basin enters Live Oak Basin, as does a part of the underflow from that basin. The latter is estimated to average 3,320 acre-feet annually. i - • i TABLE 104. SURFACE INFLOW TO LIVE OAK BASIN Average annual for 32-year period, 1904-05 to 1935-36, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38, inclusive (Acre-feet) 32-year 21-year 11-year period period period From directly tributary mountains Measured during part of period 210 180 140 Estimated" 60 50 40 From other basins Claremont Heights 160 140 130 Total" 430 370 310 • Includes a relatively small amount of underflow. * Values of change in storage and precipitation, also required, are presented In Tables 5 and 7. SOUTH COASTAL BASIN INVESTIGATION 167 Import In Table 105 estimated values of imports of water for each year since 1927-28 are presented. There is no import of sewage. During the 11-year period, an annual average of 1,810 acre-feet of water was imported from San Dimas, Claremont Heights and Pomona Basins. Estimated average annual import under present conditions is 2,030 acre-feet, equal to the average for the four-year period, 1941-42 to 1944-45, inclusive. TABLE 105. IMPORT TO LIVE OAK BASIN Year Acre-feet Year Acre-feet Year Acre-feet 1927-28 1,320 1928-29 1,630 1929-30 1,570 1930-31 1,800 1931-32 1,910 1932-33 2,080 1933-34 2,080 1934-35 1,660 1935-36 2,110 1936-37 1,990 1937-38 1,730 1938-39 1,610 1939-40 1,580 1940-41 1,510 1941-42 1,900 1942-43 2,050 1943-44 1,960 1944-45 2,210 Consumptive Use In Table 106 estimates of consumptive use based on culture surveys conducted by the Division of Water Resources in 1932 and 1942 are presented. Unit consumptive use is discussed in Chapter V. While soils covering a considerable part of Live Oak Basin are rocky and difficult to work, about 82 percent of the area is profitably devoted to production of citrus fruits. Industrial development is negligible and domestic use relatively small. Brush covers most of the unused land. TABLE 106. ESTIMATED AVERAGE ANNUAL CONSUMPTIVE USE IN LIVE OAK BASIN Type of culture Unit con- sumptive 1932 19/^2 use, feet Acres Acre-feet Acres Acre-feet Valley area Avocado and citrus Domestic and industrial Unirrigated 32- and 21-year periods 11-year period Subtotal 32- and 21-year periods. 11-year period Mountain area Avocado and citrus Grand total 32- and 21-year periods llryear period 2.0 1,624 3,248 1,624 3,248 1.5 32 48 37 56 317 312 ^_^ _ 1.5 468 1.484 470 0.4^ 1,973 34 2,007 3,766 14 3,780 1,973 34 2,007 3,772 14 3,786 • Difference between irrigated culture and natural vegetation. 168 DIVISION OF WATER RESOURCES Export In Table 107 estimated exports of water to San Dimas and Pomona Basins for each year since 1927-28 are presented. There is no sewage out- flow. During the 11-year period an annual average of 1,170 acre-feet of water was exported. Estimated average annual export under present conditions is 1,280 acre-feet, equal to the average for the four-year period, 1941-42 to 1944-45, inclusive. TABLE 107. EXPORT FROM LIVE OAK BASIN Year Acre-feet Year Acre-feet Year Acre-feet 1927-28 1,100 1933-34 1.200 1939-40 960 1928-29 1,400 1934-35 950 1940-41 950 1929-30 1,260 1935-36 1,100 1941-42 1,230 1930-31 1,190 1936-37 1,140 1942-43 1,270 1931-32 1,320 1937-38 1,010 1943-44 1,160 1932-33 1,220 1938-39 980 1944-45 1,440 Surface Outflow Outflow on the surface includes part of the inflow from directly tributary mountains, part of that from Claremont Heights Basin and runoff originating in precipitation on the overlying valley. It is estimated to average 360 acre-feet, 330 acre-feet and 300 acre-feet annually in the 32-, 21- and 11-year periods, respectively, as derived in Table 108. Mountain inflow is mostly in Live Oak Creek, which flows 1.9 miles across the basin. Records of daily discharge from Live Oak Reservoir and at Station 4457 during the 11-year period are available. Eleven-year average annual outflow in the creek is estimated by using these records and a percolation curve which results in complete percolation up to four second-feet. Thirty-two- and 21-A^ear average outflows are assumed pro- portional to estimated average annual runoff at the gaging station. Estimated outflow from other sources includes 50 percent of inflow from directly tributary mountains, 50 percent of inflow from other basins, and 5 percent of precipitation on the overlying valley area. TABLE 108. SURFACE OUTFLOW FROM LIVE OAK BASIN Average annual for 32-year period, 1904-05 to 193 5-36, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-3 8, inclusive (Acre-feet) S2't/ear 21-year 11-year period period period Estimated, originating in Live Oak Creek 90 80 60 Directly tributary mountains 30 20 20 Inflow from other basins 80 70 60 Precipitation on valley land 160 160 160 a Total 360 330 300 ■ Based on dally discharges at gaging station and percolation curve. SOUTH COASTAL BASIN INVESTIGATION 169 Excess Assuming that the 21-year period is the cycle of long-time mean supply, estimated annual excess is 210 acre-feet, as derived in Table 109. If 32-year mean values are substituted in the table the derived annual excess is 240 acre-feet. TABLE 109. ESTIMATED ANNUAL EXCESS IN LIVE OAK BASIN UNDER PRESENT CONDITIONS ASSUMING THE 21-YEAR PERIOD, 1922-23 TO 1942-43, INCLUSIVE, TO BE ONE OF LONG-TIME MEAN SUPPLY (Acre-feet) Estimated Actual long-time 11-year mean annual base under period present average Differ- conditions annual ence Average annual increase in storage during base period 10 Items tending to increase the rise Precipitation 3,280 3.210 70 Surface inflow 370 310 60 Import 2,030 1,810 220 Subtotal to be added 350 Items tending to decrease the rise Consumptive use Surface outflow Export 3,790 3,780 10 330 300 30 1.280 1,170 110 Subtotal to be subtracted 150 Excess 210 < .. . , ■ - ■ — ■ ■ - Subsurface Outflotv Assuming that all items involved have been correctly evaluated, subsurface outflow during the 11-year base period must, in accordance with principles set forth in Chapter V, have averaged 3,390 acre-feet annually, as derived in Table 110. TABLE 110. ESTIMATED AVERAGE ANNUAL SUBSURFACE OUTFLOW FROM LIVE OAK BASIN DURING THE 11-YEAR PERIOD, 1927-28 TO 1937-38, INCLUSIVE Acre- feet Water entering basin Precipitation 3,210 Surface inflow 310 Import 1,810 Underflow 3,320 Water coming from storage in basin — 10 Subtotal 8,640 Water leaving basin on surface Surface outflow 300 Export 1,170 Consumptive use 3,780 Subtotal 5,250 Subsurface Outflow — to Pomona Basin 3,390 170 DIVISION OF WATER RESOURCES POMONA BASIN (19) Pomona Basin is located in the northwesterly portion of Upper Santa Ana Valley, and covers about 8.5 square miles. It is bounded on the southwest by San Jose Hills, on the north by Live Oak and Claremont Heights Basins, and on the southeast by Chino Basin. Topography is for the most part regular, with slope averaging about 125 feet per mile in a direction generally a little west of south. Elevations above sea level range from 900 to 1,350 feet. Soils are mostly lighter members of the Hanford series, and are quite receptive of moisture. About 21 percent of the area is covered by culture of a municipal type, about 59 percent is devoted to agriculture, and about 20 percent is in a more or less natural state. The local water supply, utilized through pumping from ground water, originates in precipitation on the valley, inflow from 380 acres of hills directly tributary to the basin, and surface and subsurface inflow from Live Oak and Claremont Heights Basins. Imported water provides a relatively large addition to the supply. A considerable part of the surface inflow and precipitation flows out into Spadra and Chino Basins, together with some underflow into the latter, and water is exported in relatively large amount to San Dimas, Chino, Live Oak and Spadra Basins, with a little to Main San Gabriel and Claremont Heights Basins. Sewage is exported for use in Puente Basin. In this basin, long-time mean annual net supply under present conditions is less than present annual demand, so an overdraft exists. Evaluation of items required* to estimate its amount follows. Inflotv Estimated annual surface inflow averages 420 acre-feet, 390 acre- feet and 360 acre-feet in the 32-, 21- and 11-year periods, respectively, as derived in Table 111. The estimate of 32-year annual inflow from 380 acres of directly tributary hills is based on the assumption that, if water is available, average consumptive use on the hills is 17 inches, inflow however being never less than 9-| percent of precipitation thereon. The 11-year value is estimated to be 0.98 times the 32-year mean, this being the ratio between 11- and 32-year mean, precipitation on the area represented by the San Gabriel Group. The corresponding ratio for the 21-year period is 1.00. t All subsurface outflow from Live Oak Basin, and a part of that from Claremont Heights Basin is assumed to enter Pomona Basin. Estimated average subsurface inflow from these sources amounts to 3,390 and 1,000 acre-feet, respectively, a total of 4,390 acre-feet annually. * Values of change in storage and precipitation, also required, are presented in Tables 5 and 7. t If runoff from hills is assumed to follow the same regimen as flow in San Gabriel River, average annual inflow during the 21-year period is 50 acre-feet, the same as for the 11-year period. SOUTH COASTAL BASIN INVESTIGATION 171 TABLE 111. SURFACE INFLOW TO POMONA BASIN Average annual for 32-year period, 1904-05 to 193 5-36, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38, inclusive (Acre-feet) 32-year 21-year 11-year period period period i From directly tributary hills Estimated » 60 60 60 From other basins Live Oak 360 330 300 Total 420 390 360 • Includes a relatively small amount of underflow. Import In Table 112 estimated values of imports of water for each year since 1927-28 are presented. There is no import of sewage. During the 11-year period, an average of 3,930 acre-feet was imported from both gravity and pumped sources in San Dimas, Claremont Heights and Live Oak Basins. The amount of water imported depends to some extent upon the amount of gravity water available. Gravity diversions cannot be expected to maintain the high values of recent years of above-normal rainfall and stream-flow over a long-time cj^cle of supply, and it therefore assumed that average annual import of gravity w^ater from Claremont Heights Basin under present conditions is equal to its average for the 21-year period. Assuming further that present average annual import from other sources is the average for the four year period, 1941-42 to 1944-45, inclusive, present import totals 4,600 acre-feet annually. TABLE 112. IMPORT TO POMONA BASIN Year Acre-feet Year Acre-feet Year Acre-feet 1927-28 3,820 1933-34 2,890 1939-40 4,490 1928-29 3,650 1934-35 3,220 1940-41 4,610 1929-30 4,050 1935-36 4,620 1941-42 5,030 3930-31 3,380 1936-37 4,480 1942-43 4,150 1931-32 3,520 1937-38 5,640 1943-44 4,920 1932-33 3,920 1938-39 4,920 1944-45 5,200 Consufttptive Use In Table 113 estimates of consumptive use based on culture surveys conducted by the Division of Water Resources in 1932 and 1942 are presented. Unit consumptive use is discussed in Chapter V. Municipal development includes the City of Claremont, and portions of the cities of La Verne and Pomona. Natural vegetation growing on unused land is mostly light brush, weeds and grass. 172 DIVISION OF WATER RESOURCES TABLE 113. ESTIMATED AVERAGE ANNUAL CONSUMPTIVE USE IN POMONA BASIN Type of culture Unit con- sumptive 19S 194 2 use, feet Acres Acre-feet Acres Acre- feet 1.3 21.5 280 45 58 2.0 2,828 5,6.56 2,871 5,742 1.8 429 772 324 583 3.0 3 9 1.5 1,022 1,533 1,155 1,732 .._—"« 961 ^ — — — > 1,063 1.4 , 1,488 1.38.5 1,331 Valley Area Garden and field Avacado and citrus Deciduous Irrigated grass Domestic and industrial Unirrigated 32- and 21-year periods. 11-year period Subtotal 32- and 21-year periods. 11-year period 5,458 5,458 9,581 9,603 Hill area Garden and field Avocado and citrus Deciduous Irrigated grass Domestic and industrial. Subtotal 0* 4 4 0.6 "^ 29 17 29 17 0.4 » 10 4 10 4 1.6 » 15 24 15 24 0.1 » 15 2 58 45 73 47 Grand total 32- and 21-year periods. 11-year period 5,516 5,.531 9,626 9,650 • Difference between irrigated culture and natural vegetation. Export In Table 14 estimated exports of water and sewage for each year since 1927-28 are presented. Water is exported to Main San Gabriel, San Dimas, Chino, Claremont Heights, Live Oak and Spadra Basins, while sewage goes to Puente Basin. During the ll-year period an annual average of 8,260 acre-feet of water, and 370 acre-feet of sewage was exported, a total of 8,630 acre-feet. Average annual exports of water under present conditions, by all but one exporter whose import to San Dimas Basin ranges up to a fixed maximum depending upon the amount of gravity water available in that basin, are assumed the same as the average for the four-year period, 1941-42 to 1944-45, inclusive. The total is 8,120 acre-feet. Sewage outflow, assumed equal to the value for 1944-45 amounts to 740 acre-feet per year. The total for both water and sewage is 8,860 acre-feet per year. TABLE 114. EXPORT FROM POMONA BASIN (Acre-feet) Year Water Sewage Year Water Sewage 1927-28 10,180 1928-29 9,950 1929-30 9,370 1930-31 9,690 1931-32 8,700 1932-33 8,270 1933-34 7,520 1934-35 5,690 1935-36 7,990 290 1936-37 320 1937-38 320 1938-30 3.50 1939-40 360 1940-41 330 1941-42 350 1942-43 410 1943-44 410 1944-45 6,030 7,.510 7,070 6,920 6,200 6,470 7,620 7,460 7,790 470 460 460 480 510 590 700 740 740 SOUTH COASTAL BASIN INVESTIGATION 173 Surface Out flow Outflow on the surface includes part of the inflow from directly tributary hills, part of that from Live Oak Basin and runoff originating in precipitation on the overlying valley. It is estimated to average 1,200 acre-feet, 1,180 acre-feet and 1,140 acre-feet annually in the 32-, 21- and 11-year periods, respectively, as derived in Table 115. Inflow to this basin directlj^ from hills enters the channel of San Jose Creek not far from its point of outflow, and it is assumed that 50 percent of this inflow leaves the basin. Inflow from Live Oak Basin is in several channels, all of which are confined and most of which are paved through- out the greater part of their length in the basin. There is, however, some percolation opportunity in unpaved sections. A part of this inflow even- tually reaches Spadra Basin, and a part goes to San Dimas Basin. It is assumed that 50 percent of that tributary to the former, and 100 percent of that tributary to the latter leaves Pomona Basin. Of precipitation on the valley, it is assumed that 10 percent of that tributary to Spadra and Chino Basins, and 15 percent of that tributary to San Dimas Basin flows out. TABLE 115. SURFACE OUTFLOW FROM POMONA BASIN Average annual for 32-year period, 1904-05 to 1935-36, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38, inclusive (Acre-feet) 32-year 21-year 11-year period period period Estimated, originating in Directly tributary hills 30 Inflow from other basins 250 Precipitation on valley land 920 Total 1,200 1,180 1,140 Overdraft Assuming that the 21-year period is the cycle of long-time mean supply, estimated annual overdraft is 2,170 acre-feet, as derived in Table 116. If 32-year mean values are substituted in the table, the derived annual overdraft is 2,160 acre-feet. 30 30 230 210 920 900 174 DIVISION OF WATER RESOURCES TABLE 116. ESTIMATED ANNUAL OVERDRAFT IN POMONA BASIN UNDER PRESENT CONDITIONS ASSUMING THE 21 -YEAR PERIOD, 1922-23 TO 1942-43, INCLUSIVE, TO BE ONE OF LONG-TIME MEAN SUPPLY (Acre-feet) Estimated Actual long-time 11-year mean annual base under period present average Differ- conditions annual ence Average annual drop in storage during base period 2,760 Items tending to increase the drop Consumptive use 9,650 9,630 20 Export 8,860 8,630 230 Surface outflow 1,180 1,140 40 Subtotal to be added 290 Items tending to decrease the drop Precipitation 8,660 8,480 180 Surface inflow 390 360 30 Import 4,600 3,930 670 Subtotal to be subtracted 880 OVEEDRAFT 2,170 Subsurface Outflow Assuming that all items involved have been correctly evaluated, subsurface outflow during the 11-year base period, must, in accordance with principles set forth in Chapter V, have averaged 520 acre-feet annually, as derived in Table 117. TABLE 117. ESTIMATED AVERAGE ANNUAL SUBSURFACE OUTFLOW FROM POMONA BASIN DURING THE 11-YEAR PERIOD, 1927-28 TO 1937-3 8, INCLUSIVE Acre-feet Water entering basin Precipitation 8,480 Surface inflow 360 Import 3.930 Subsurface inflow 4,390 AVater coming from storage in basin 2,760 Subtotal 19,920 Water leaving basin on surface Surface outflow 1,140 Exported water 8,260 Exported sewage 370 Consumptive use 9,630 Subtotal 19,400 Subsurface Outflow — to Chino Basin 520 SOUTH COASTAL BASIN INVESTIGATION 175 CUCAMONGA BASIN (20) Cucamonga Basin is located in the northwesterly portion of Upper Santa Ana Valley, and covers about 13 square miles. It is bounded on the southwest, south and east by Chino Basin, and on the north by San Gabriel Mountains. Topography is definitely irregular at its southern boundary. Elsewhere many minor irregularities, typical of the upper portion of cones generally, cover a considerable part of the area. Slope ranges between 200 and 250 feet per mile, in a direction a little east of south. Elevations range from 1,250 to about 2,300 feet above sea level. Soils covering this basin are mostly lighter members of the Hanford and Tujunga series, with a fairly large area of less pervious Placentia loam near the lower boundary. Municipal development occupies only about 2 percent of the area, about 46 percent is devoted to agriculture, and the remainder is in a more or less natural state. The local water supply, utilized to a minor extent through diversion from surface streams, but more through pumping from ground water, originates in precipitation on the valley, and inflow from 9,370 acres of mountains directly tributary to the basin. Imported water provides a relatively large addition to the supply. A considerable part of the surface inflow and precipitation flows out into Chino Basin, together with some underflow, and water is exported in relatively large amount to the same basin. In this basin, long-time mean annual net supply under present con- ditions is greater than present annual demand, so an excess exists. Evaluation of items required * to estimate its amount follows. Inflow Estimated annual surface inflow averages 8,300 acre-feet, 7,870 acre-feet and 7,450 acre-feet in the 32-, 21- and 11-year periods, respec- tively, as derived in Table 118. Annual inflow from a portion of the directly tributary mountain area was measured in Cucamonga Creek at Station 4572 during a part of each period. The 32- and 21-year values are derived by comparison with San Antonio Creek. The estimate of the 32-year mean annual inflow from 2,900 acres of mountains directly tributary to the basin is based on the assumption that average consumptive use on mountain area is 17 inches. The 11- year and 21-year values are estimated to be, respectively, 0.91 and 0.95 times the 32-year mean, these being the ratios between 11- and 21-year averages, and 32-year mean discharge of San Antonio Creek. The only subsurface inflow is that indicated by note in Table 118. * Values of change in storage and precipitation, also required, are presented in Tables 5 and 7. 176 DIVISION OF WATER RESOURCES TABLE 118. SURFACE INFLOW TO CUCAMONGA BASIN Average annual for 32-year period, 1904-05 to 193 5-36, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38, inclusive (Acre-feet) 32-year period 21-year period 5,810 2,060 7,870 11-year period From directly tributary mountains Measured during part of period 6,130 Estimated' 2,170 Total 8,300 5,470 1,980 7,450 » Includes a relatively small amount of underflow. Import In Table 119 estimated values of imports of water for each year since 1927-28 are presented. There is no import of sewage. Gravity water is imported from Claremont Heights Basin and spread in Cucamonga Wash. Pumped water is imported from Chino Basin. During the 11- year period, an annual average of 3,840 acre-feet of water was imported. The amount of gravity water imported depends to some extent upon the amount available. Total gravity diversions from San Antonio Canyon and the portion diverted to Cucamonga Basin have been measured since 1918 and since 1927-28 respectively. Average annual import of gravity water under present conditions is estimated to equal the mean diversion from San Antonio Creek during the 21-year period multiplied by the ratio between diversion to Cucamonga Basin and total diversion since 1927-28. Assuming that present import of water pumped in Chino Basin equals its average for the four-year period, 1941-42 to 1944-45, inclusive, estimated total present average annual import to Cucamonga Basin is 4,340 acre-feet. TABLE 119. IMPORT TO CUCAMONGA BASIN Year Acre-feet Year Acre-feet Year Acre- feet 1927-28 2,370 1928-29 2,190 1929-30 3,010 1930-31 2,790 1931-32 4,900 1932-33 2,290 1933-34 1,930 1934-35 6,770 1935-36 3,490 1936-37 6,620 1937-38 5,920 1938-39 3,540 1939-40 6,050 1940-41 7,580 1941-42 5,080 1942-43 5,160 1943-44 6,730 1944-45 6,110 Consumptive Use In Table 120 estimates of consumptive use based on culture surveys conducted by the Division of Water Resources in 1932 and 1942 are presented. Unit consumptive use is discussed in Chapter V. Municipal development is small and industrial development negligible. Natural vegetation growing on unused land is largely brush, weeds and grass. SOUTH COASTAL BASIN IX^'ESTIGATION 177 TABLE 120. ESTIMATED AVERAGE ANNUAL CONSUMPTIVE USE IN CUCAMONGA BASIN Unit con- sumptive 1932 1942 Type of culture use, feet Acres Acre-feet Acres Acre-feet Valley area Garden and field 1.3 211 274 176 229 Avocado and citrus 2.3 2,768 6.366 3,363 7,735 Deciduous 2.1 390 819 375 788 Alfalfa 3.0 5 15 5 15 Domestic and industrial 1.8 147 265 167 301 Unirrigated 5,007 4,442 32 -year period 1.5 6,663 21-year period 1.492 6,627 11-year period 1.473 7,375 Subtotal 8,528 8,528 32-year period 15,731 21-year period 15,695 11-year period 15,114 flountain area Avocado and citrus 0.8* 15 12 15 12 Grand total 8,543 8,543 32-year period 15,743 21-year period 15,707 11-year period 15,126 * Difference between irrigated culture and natural T^etation. Export In Table 121 estimated exports of water for each year since 1927-28 are presented. There is no sewage outflow. During the 11-year period, an annual average of 10,060 acre-feet of water was exported to Chino Basin from wells and tunnels in the alluvium. Nearly half the total export is by an entity which also diverts by gravity from San Antonio Canyon. Less pumped water is required when more gravity water is available. Average annual export by this entity, under present condi- tions, is assumed to equal its average for the four-year period, 1911-42 to 1944-45. inclusive, multiplied by the ratio between the four-year and 21-year average annual diversions from San Antonio Canyon. The remainder of the export is independent of gravity diversions and is assumed equal to the four-year average. Estimated present average annual export totals 10,240 acre-feet. TABLE 121. EXPORT FROM CUCAMONGA BASIN Year Acre-feet Year Acre-feet Year Acre-feet 1927-28 10,740 1933-34 12,370 19.39-40 7.720 1928-29 12,370 1934-35 7,030 1940-41 5.550 1929-30 11.550 1935-36 10.780 1041-42 8,980 1930-31 12.000 1936-37 6.240 1942-43 8.640 1931-32 9,100 1937-38 6,980 1943-44 9,090 1932-33 11,480 1938-39 9,840 1944-45 9,260 12—71061 178 DIVISION OF WATER RESOURCES Surface Outflow Outflow on the surface includes part of the inflow from directly tributary mountains and runoff originating in precipitation on the over- lying valle}'. It is estimated to average 1,390 acre-feet, 1,080 acre-feet and 1,200 acre-feet annually in the 32-, 21- and 11-year periods, respec- tively, as derived in Table 122. The greater part of the mountain inflow is concentrated in Cuca- monga Creek, which flows southward four miles across the basin. In its upper reaches 12 rock and wire wall dams extend across the arroyo in which the stream flows. While intended primarily for retention of debris, these walls effect some spreading. Spreading grounds below these cross walls were destroyed in 1938. During the 1933-31 season a peak flow of approximately 300 second-feet was entirely absorbed within the area of 65 acres enclosed by the cross walls. None of the channels of Cucamonga Creek, nor of the much smaller streams on either side are paved, but flow past the spreading ground area occurs on so few days that percolation in the channel below is not considered. Outflow since 1927-28, when Station 4572 was established, is estimated by subtracting 300 second-feet from daily discharges $lt that station. From the relationship thus established between inflow and outflow during years of record, 32- and 21-3^ear mean annual outflows in Cucamonga Creek are estimated. Estimated outflow from other sources includes 25 percent of the inflow from directly tributary mountains, and 2 percent of the precipi- tation on valle}^ area within the basin. TABLE 122. SURFACE OUTFLOW FROM CUCAMONGA BASIN Average annual for 32-year period, 1904-05 to 193 5-36, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38, inclusive (Acre-feet) Estimated, originating in Cucamonga Creek Directly tributary mountains. Precipitation on valley land_- Total S2-year period 21-year period 11-year period 530 240 520 320 400 540 490 320 310 1,390 1,080 1,200 Excess Assuming that the 21-year period is the cycle of long-time mean supply, estimated annual excess is 290 acre-feet, as derived in Table 123. If 32-year mean values are substituted in the table, the derived excess is 540 acre-feet. SOUTH COASTAL BASIN INVESTIGATION 179 TABLE 123. ESTIMATED ANNUAL EXCESS IN CUCAMONGA BASIN UNDER PRESENT CONDITIONS ASSUMING THE 21 -YEAR PERIOD, 1922-23 TO 1942-43, INCLUSIVE, TO BE ONE OF LONG-TIME MEAN SUPPLY (Acre-feet) Estimated Actual long-time 11-year mean annual base under period present average Differ conditions annual ence Average annual drop in storage during base period 400 Items tending to decrease tiie drop Precipitation 15,870 15,460 410 Surface inflow 7,870 7,450 420 Import 4,340 3,840 500 Subtotal to be subtracted 1,330 Items tending to increase the drop Consumptive use 15,710 15,130 580 Export 10,240 10,060 180 Surface outflow 1,080 1,200 —120 Subtotal to be added 640 Excess 290 Subsurface Outflotv Assuming that all items involved have been correctly evaluated, subsurface outflow during the 11-year base period, must, in accordance with principles set forth in Chapter V, have averaged 760 acre-feet annually, as derived in Table 124. TABLE 124. ESTIMATED AVERAGE ANNUAL SUBSURFACE OUTFLOW FROM CUCAMONGA BASIN DURING THE 11-YEAR PERIOD, 1927-28 TO 1937-3 8, INCLUSIVE Acre- feet Water entering basin Precipitation 15,460 Surface inflow 7,450 Import = 3,840 Water coming from storage in basin 400 Subtotal 27,150 Water leaving basin on surface Surface outflow 1,200 Export 10,060 Consumptive use 15,130 Subtotal 26,390 Subsurface Outflow — to Chino Basin 760 180 DIVISION OF WATER RESOURCES RIALTO BASIN (21a) Rialto Basin is located in the north central portion of Upper Santa Ana Valley, and covers about 22 square miles. It is bounded on the southwest by Chino Basin, on the northwest by San Gabriel Mountains, on the northeast by Lytle Basin, and on the east by Colton Basin. Topography is regailar, except in the north portion along the channel of Lytle Creek where it exhibits characteristics common to outwash areas. Slope is generally southerly, and ranges from 80 to 150 feet per mile, being steeper near the mountains. Elevations above sea level range from 1,150 at its southerly tip, to 2,250 feet at the mouth of Lytle Canyon. Soils are mostly lighter members of the Hanford series, and are quite receptive of moisture. Municipal development occupies less than 1 per- cent of the area, about 17 percent is devoted to agriculture, and tJie remainder is largely in a natural state. The local water supply, utilized to a considerable extent through diversion from surface streams, but also through pumping from ground water, originates in precipitation on valley lands, and inflow from 36,660 acres of mountains directly tributary to the basin. Some water is imported. A considerable part of surface inflow and precipitation flows out into Lj'tle and Chino Basins, together with some underflow into Chino Basin, and water is exported in relatively large amount to Chino, Colton and Lvtle Basins. Long-time mean annual net supply to Rialto Basin under present conditions is slightly less than present annual demand if the 21-year period is assumed to represent the long-time mean cycle of supply, and somewhat greater if the 32-year cycle is used, indicating an overdraft under one assumption and an excess under the other. Evaluation of items required* to estimate the amount of overdraft or excess follows. Inflow Estimated annual surface inflow averages 37,130 acre-feet, 35,190 acre-feet and 33,730 acre-feet in the 32-, 21- and 11-year periods, respec- tively, as derived in Table 125. Inflow from a portion of the directly tributary mountain area was measured at Station 19449 on Lytle Creek during the 11- and 21-year periods. The 32-year value is derived b}^ comparison w^ith San Antonio Creek. The estimate ef 32-year mean annual inflow from 6,180 acres of mountains directly tributary to the basin, and downstream from the gaging station at which above inflow was measured, is based on the assumption that average consumptive use on mountain area is 19 inches. The 11-year value is estimated to be 0.91 times the 32-year mean, this being the ratio between 11- and 32-year mean discharge of San Antonio Creek. The corresponding ratio for the 21-year period is 0.95. It is assumed that the only subsurface inflow is that indicated by note in Table 125. * Values of change in storage and precipitation, also required, are presented in Tables 5 and 7. SOUTH COASTAL BASIN INVESTIGATION 181 TABLE 125. SURFACE INFLOW TO RIALTO BASIN Average annual for 32-year period, 1904-05 to 193 5-36, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38, inclusive (Acre-feet) 32-i/ear 21-year 11-year period period period From directly tributary mountains Measured during part of period 32,210 30,510 29,240 Estimated "» 4,920 4,680 4,490 Total 37,130 35,190 33,730 » Includes a relatively small amount of underflow. Iffiport In Table 126 estimated values of imports of water from Lytle and Colton Basins for each year since 1927-28 are presented. No sewage is imported. During the 11-year period the import averaged 4,930 acre-feet annually. Estimated average annual import of water under present con- ditions is 5,720 acre-feet, equal to the average for the four-year period, 1941-42 to 1944-45, inclusive. TABLE 126. IMPORT TO RIALTO BASIN Year Aore-feet Year Acre-feet Year Acre-feet 1927-28 6.270 1933-34 6,580 1939-40 5,570 1928-29—1 6,030 1934-35 3,990 1940-41 2,950 1929-30 4,910 1935-36 — __ 5,380 1941-42 5,450 1930-31 5,320 1936-37 3,670 1942-43 6,060 1931-32 3,740 1937-38 3,890 1943-44 6,110 1932-33 4,420 1938-39 6,870 1944-45 5,260 Consuvtptive Use In Table 127 estimates of consumptive use based on culture surveys conducted by the Division of Water Resources in 1932 and 1942 are presented. Unit consumptive use is discussed in Chapter V. Only about 17 percent of the area is devoted to irrigated crops. Domestic develop- ment is small and there is no industrial development. A relatively small part of the unirrigated land is in grapes, the rest being covered in large part by light to medium brush, with some weeds and grass in lower portions of the basin. 182 DIVISION OF WATER RESOURCES TABLE 127. ESTIMATED AVERAGE ANNUAL CONSUMPTIVE USE IN RIALTO BASIN Unit con- sumptive 1932 19Jf2 Type of culture use, feet Acres Acre-feet Acres Acre-feet Valley area Garden and field 1.4 37 Avocado and citrus 2.5 2,022 Deciduous 2.3 338 Domestic and industrial 1.8 95 Unirrigated 11,722 32-year period 1.6 21-year period 1.006 11-year period 1.594 Total 14,214 32-year period 21-year period 11-year period 24,740 52 22 31 5,055 2,132 5,330 777 263 605 171 100 180 — — — ^ 11,697 — — — ^ 18,715 18,785 18,685 14,214 24,861 24,931 Export In Table 128 estimated exports of water for each year since 1927-28 are presented. There is no sewage outflow. Water is exported to Chino, Colton and Lytic Basins from both gravitj^ and pumped sources. Gravity water from Fontana Power House not needed for use is released back into Lytic Creek channel, for spreading and percolation in Lytic Basin. During the 11-year period an annual average of 22,090 acre-feet of water was exported. The amount of water exported depends to some extent upon the amount of gravity water available. Average annual release from the power house back to Lytic Creek channel is assumed to equal the average power diversion from Lytic Creek for the 21-year period, multiplied by the ratio between amount released and amount diverted for the period of dual record, 1926-27 through 1944-45. For that portion of export for direct use which appears to have correlation with the amount diverted from Lytle Creek, average annual export under present conditions is estimated to equal the average diversion for the 21-year period, multi- plied by the ratio between average export and average diversion for the period of dual record available, 1927-28 through 1944-45. For the remainder, average annual export under present conditions is assumed to equal the average for the four-year period, 1941-42 to 1944-45, inclu- sive. Estimated^present average annual export totals 25,000 acre-feet. TABLE 128. EXPORT FROM RIALTO BASIN Year Acre-feet Year Acre-feet Year Acre-feet 1927-28 20.4.30 19.33-.34 15,690 1939-40 25,920 1928-29 15,090 1934.35 25.250 1940-41 35,730 1929-30 17,260 1935-36 20,320 1941-42__ 27,410 1930-31 15,130 1936-37 34,420 1942-43 34,580 1931-32 24,610 1937-38 35,550 1943-44 38,440 1932-33 19,210 1938-39 26,840 1944-45 31,760 SOUTH COASTAL BASIN INVESTIGATION 183 Surface Outflotv Outflow on the surface includes part of the inflow from directly tributary mountains and runoff originating in precipitation on over- lying valley land. It is estimated to average 8,550 acre-feet, 9,650 acre- feet and 10,210 acre-feet annually in the 32-, 21- and 11-year periods, respectivel}^, as derived in Table 129. The greater part of inflow to this basin is in Lytic Creek, which flows in an unpaved and largely unconfined channel 4.5 miles along the north- easterly boundary, partly in Rialto Basin and partly in Lytic Basin. Water is diverted from Lytic Creek at the mouth of the canyon to develop power at the Fontana Power House, approximately two-thirds of the way down the basin. Discharge from the power house is used for irrigation when needed, either Avithin the basin or by export, or is released back into Lytic Creek channel in Lytic Basin for spreading and percolation therein. The amount thus released is treated as export rather than outfloAV. It is believed that operation of extensive spreading grounds constructed on the upper Lytle Creek cone in 1925 and destroyed by the flood of March, 1938, had little effect on outflow during the 11-year period. Discharge of Lytle Creek has been measured at Station 19449 just below the power diversion since 1918-19. Fontana Union Water Com- pany has measured floAV at several points downstream on the cone of the creek since March, 1938, from which data actual percolation between the power diversion and the junction Avith Cajon Creek has been deter- mined. Percolation in this reach from 1918-19 to March, 1938, is estimated from a standard percolation curve Avhich approximates observed perco- lation since March, 1938, and results in complete percolation up to 75 second-feet. Surface outfloAV from sources above Station 19449 is estimated for the 11- and 21-year periods from daily discharge measure- ments at the gaging station, using above percolation data, and assuming that 40 percent of percolation between the poAver diversion and junction Avith Cajon Creek occurs in Rialto Basin. For the 32-year period, annual runoff at Station 19449 prior to 1918-19 is estimated by comparison Avith San Antonio Creek. Yearly outfloAv from the basin prior to 1918-19 is then estimated from its relationship Avith runoff at Station 19449. Out- flow from sources entering below the poAver diversion is estimated to be 50 percent of infloAV from 2,340 acres of directly tributary mountains. Surface outfloAv from Rialto Basin in Lytle Creek enters Lytle Basin. Estimated outflow to Chino Basin includes 50 percent of inflow from about 1,460 acres and 90 percent from 1,740 acres of directly tributary mountains, and 2 percent of precipitation on tributary valley land Avithin Rialto Basin. 184 DIVISION OF WATER RESOURCES TABLE 129. SURFACE OUTFLOW FROM RIALTO BASIN Average annual for 3 2-year period, 1904-0 5 to 193 5-3 6, inclusive; 21 -year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38, inclusive (Acre-feet) 32-year 21-year 11-year period period period All estimated To Lytle Basin, originating in Lytle Creek, above gaging station 5,320 Directly tributary mountains, below station 1,260 Subtotal 6,580 To Chino Basin, originating in Directly tributary mountains 1,580 Precipitation on valley land 390 Subtotal 1,970 Total 8,550 9,650 10,210 Overdraft Assuming that the 21-year period is the cycle of long-time mean supply, estimated annual overdraft is 220 acre-feet, as derived in Table 130. If 32-year mean values are substituted in the table, an annual excess of 2,670 acre-feet is indicated. 6,570 1,200 7,250 1,140 7,770 1,490 390 8,390 1,440 380 1,880 1,820 "J TABLE 13 0. ESTIMATED ANNUAL OVERDRAFT IN RIALTO BASIN UNDER PRESENT CONDITIONS ASSUMING THE 21-YEAR PERIOD, 1922-23 TO 1942-43, INCLUSIVE, TO BE ONE OF LONG-TIME MEAN SUPPLY (Acre-feet) Estimated Actual long-time 11-year mean annual tase under period present average Differ- conditions annual ence Average annual drop in storage during base period 340 Items tending to increase the drop Consumptive use 24,930 24,740 190 Surface outflow 9.650 10,210 —560 Export 25,000 22,090 2,910 Subtotal to be added 2,540 Items tending to decrease the drop Precipitation 25,010 24,600 410 Surface inflow 35,190 33,730 1,460 Import 5,720 4,930 790 Subtotal to be subtracted 2,660 OV^ERDRAFT 220 SOUTH COASTAL BASIN INVESTIGATION 185 Subsurface Outflow Assuming that all items involved have been correctly evaluated, subsurface outflow during the 11-year base period, must, in accordance with principles set forth in Chapter V, have averaged 6,560 acre-feet annually, as derived in Table 131. TABLE 131. ESTIMATED AVERAGE ANNUAL SUBSURFACE OUTFLOW FROM RIALTO BASIN DURING THE 11-YEAR PERIOD, 1927-28 TO 1937-38, INCLUSIVE Acre-jeet Water entering basin Precipitation 24,600 Surface inflow 33,730 Import 4,930 Water coming from storage in basin 340 Subtotal : 63,600 Water leaving basin on surface Surface outflow 10,210 Export 22,090 Consumptive use 24,740 Subtotal 57,040 Subsurface Outflow — to Chino Basin . 6,560 LOWER CAJON BASIN (40) Lov^^er Cajon Basin is located in the extreme northerly portion of Upper Santa Ana Valley, and covers about 6.9 square miles. It is bounded on the west and southwest by San Gabriel Mountains, on the northeast and east by San Bernardino Mountains, on the southeast by Devil Canyon Basin, and on the south by Bunker Hill Basin and Shandin Hills. Topography is irregular, the result of alternate deposition and cutting by Cajon Creek, and by numerous small, flashy streams entering from mountains on the northeast and southwest. The slope, in the southeasterly direction of flow of Cajon Creek, averages about 100 feet per mile, but is much steeper immediately adjacent to the mountains. Elevations range from 1,750 to more than 2,550 feet above sea level. Soils covering this basin are mostly lighter members of the Hanford and Tujunga series, with a few small areas of light Ramona and Placentia soils, and a con- siderable area of river wash along Cajon Creek. All are quite absorptive. There is no municipal development and only 8 percent of the area is devoted to agriculture, the remaining 92 percent being largely in a natural state. The local water supply, utilized largely through diversion from springs, and to a minor extent through pumping from ground water, originates in precipitation on valley lands, inflow from 10,890 acres of mountains directly tributary to the basin, and inflow largely on the surface from Upper Cajon Basin, all of the last named as flood flow and rising water in Cajon and Lone Pine Creeks. There is no import of water or sewage. 186 DIVISION OF WATER RESOURCES A considerable part of the surface inflow and precipitation on the valley flows out into Devil Canyon and Bunker Hill Basins, together with large underflow to the latter. Pumped water has been exported to Bunker Hill Basin since 1940-41. Long-time mean annual supply entering Lower Cajon Basin under present conditions is much greater than present annual demand. Along its lower boundary, however, there is no effective barrier to underflow into Bunker Hill Basin, For this reason water, which might constitute an excess if such a barrier existed, soon leaves the basin as underflow, and it is this underflow to downstream basins which is herein estimated. Evaluation of items required * to estimate its long-time mean amount follows. Inflotv Estimated annual surface inflow averages 17,400 acre-feet, 15,230 acre-feet and 15,150 acre-feet in the 32-, 21- and 11-year periods, respec- tively, as derived in Table 132. Inflow from Upper Cajon Basin has been measured at gaging Station 19433B on Cajon Creek since 1920-21, and at Station 19433A on Lone Pine Creek during the period from 1920-21 to 1937-38, inclusive. Thirty- two year values for both streams, and the 21-year value for Lone Pine Creek, are derived by comparison with Lytle and San Antonio Creeks. The estimate of 32-year mean annual inflow from 10,890 acres of mountains directly tributary to the basin, and downstream from gaging stations at which above inflow was measured, is based on the assumption that average consumptive use on the northwesterly 7,040 acres of this mountain area is 20 inches while that on the southeasterly 3,850 acres, with greater indicated average precipitation, is 22 inches. The 11-year value is estimated to be 0.79 times the 32-year mean, this being the ratio between 11- and 32-year mean discharge of Santa Ana River. The cor- responding ratio for the 21-year period is 0.80. It is assumed that the only subsurface inflow is that indicated by note in Table 132. TABLE 13 2. SURFACE INFLOW TO LOWER CAJON BASIN Average annual for 32-year period, 1904-05 to 193 5-36, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-3 8, inclusive (Acre-feet) 32-1/ear 21-year Jl-t/ear period period period From other basins Measured during part of period 8,060 7,760 7,770 From directly tributary mountains Estimated'' 9,340 7,470 7,380 Total 17,400 15,230 15,150 " Includes a relatively small amount of underflow. * Values of change in storage and precipitation, also required, are presented in Tables 5 and 7, SOUTH COASTAL BASIN IN^^ESTIGATION 187 Consumptive Use In Table 133 estimates of consumptive use based on culture surveys conducted by the Division of "Water Resources in 1932 and 1942 are presented. Unit consumptive use is discussed in Chapter V. A relatively small part of the area is used. There is little domestic and no industrial development, but about 7 percent of the area, bench land east of Cajon Creek, is devoted to deciduous fruits, and there is a small area of irri- gated grass. Most of the remainder of the area is covered with brush. TABLE 13 3. ESTIMATED AVERAGE ANNUAL CONSUMPTIVE USE IN LOWER CAJON BASIN • Type of culture Unit con- sumptive use, feet J932 m2 Acres Acre-feet Acres Acre-feet 310 713 310 713 55 165 55 165 4,065 » 4,065 Valley area Deciduous 2.3 Irrigated grass 3.0 Unirrigated 32-year period 1.7 6,910 21-year period 1.707 6,939 11-year period 1.693 6,882 Subtotal 4,430 4,430 __-_ 32-year period 7,788 21-year period 7,817 11-year period 7,760 Expoi't In Table 134 estimated values of export of water to Bunker Hill Basin, for each year since 1940-41 when export started, are presented. There is no sewage outflow. During the 11-year period, no water was exported. Estimated average annual export of water under present conditions is 2,070 acre-feet, equal to its 1943-44 value. TABLE 134. EXPORT FROM LOWER CAJON BASIN Year Acre-feet Year Acre-feet 1940-41 1,000 1943-44 2,070 1941-42 1,530 1944-45 2,120 1942-43 1,640 Surface Outflow Outflow on the surface includes part of the inflow from directly tributary mountains, a part of that from Upper Cajon Basin and runoff originating in precipitation on the overlying valley. It is estimated to average 5,040 acre-feet, 5,200 acre-feet and 5,240 acre-feet annually in the 32-, 21- and 11-year periods, respectively, as derived in Table 135. Flows in Cajon and Lone Pine Creeks combine near the upper boundary of Lower Cajon Basin and flow approximately 6.5 miles in the natural channel of Cajon Creek, before entering Bunker Hill Basin. The two streams were measured at Stations 19433B and 19433A, respectively, 188 DIVISION OF WATER RESOURCES during the period 1920-21 to 1937-38, inclusive. After the latter year only Cajon Creek was measured. Daily discharges at Station 19433A since 1938-39 are estimated by comparison with Cajon Creek. The measured and estimated daily discharges and a percolation curve which results in complete percolation up to 84 second-feet are used to estimate outflow of water originating above the gaging stations for each year since 1920-21. Annual inflows at the two stations prior to that year are estimated by comparison with San Antonio Creek and corresponding annual outflows by comparison with the inflows. Estimated surface outflow to Bunker Hill Basin originating below the gaging stations consists of 25 percent of the inflow from 7,580 acres of directly tributary mountains, and 2 percent of the precipitation on 2,550 acres of overlying valley land. Estimated surface outflow to Devil Canyon Basin consists of 50 percent of the inflow from 3,310 acres of directly tributary mountains and 2 percent of the precipitation of 1,880 acres of overljdng valley land. TABLE 13 5. SURFACE OUTFLOW FROM LOWER CAJON BASIN Average annual for 32-year period, 1904-05 to 1935-36, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-3 8, inclusive (Acre-feet) 32-year period 21-year period 11-year period 1,500 1,350 120 2,330 1,080 120 2,400 1,070 120 2,970 1,970 100 3,530 1,570 100 3,590 1,550 100 2,070 1,670 1,650 Estimated To Bunker Hill Basin, originating in Inflow from other basins Directly tributary mountains Precipitation on valley land Subtotal To Devil Canyon Basin, originating in Directly tributary mountains Precipitation on valley land Subtotal Total 5,040 5,200 5,240 Subsurface Outjiotv All water which enters Lower Cajon Basin, including its overlying area, during am^ period, must either go into storage within the boundaries of the basin, be consumed or exported, or flow out either on the surface or underground. Since 32-, 21- and 11-year average values have been estimated for all but the last item, i.e., subsurface outflow, its value is determined as shown in Table 136. Because a relatively greater amount of stream flow data is available during the 21-year period, it is assumed to be the cycle of long-time mean supply, and estimated long-time mean annual subsurface outflow under present conditions is 11,330 acre-feet. SOUTH COASTAL BASIN INVESTIGATION 189 TABLE 13 6. ESTIMATED SUBSURFACE OUTFLOW FROM LOWER CAJON BASIN Average annual for 32-year period, 1904-05 to 1935-36, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-3 8, inclusive (Acre-feet) 32-year 21-year 11-year period period period Water entering basin Precipitation 11,090 11,190 11,000 " Surface inflow 17,400 15,230 15,150 Subtotal 28,490 26,420 26,150 Change in storage Water leaving basin on surface Surface outflow 5,040 5,200 5,240 Export 2,070 2,070 Consumptive use 7,790 7,820 7,760 Subtotal 14,900 15,090 13,000 Subsurface Outflow — to Bunker Hill Basin 13,590 11,330 13,150 _ — __ — _. — — . . __ 1 LYTLE BASIN (23) Lytle Basin is located in the north central portion of Upper Santa Ana Valley, and covers about 6.2 square miles. It is bounded on the southwest by Rialto and Colton Basins, on the north by San Gabriel Mountains, and on the northeast, east and south by Bunker Hill Basin. The basin is about seven miles long and averages about a mile wide. Its upper two-thirds is covered by outwash from Lytle and Cajon Creeks, and the topography is characteristically cut by innumerable small chan- nels. In the lower portion cutting is deeper, and irregularities are fewer but more pronounced. Slope varies from 75 to 200 feet per mile, and is generally to the southeast. Elevations above sea level range from 1,180 to about 2,100 feet. Soils include lighter members of the Hanford and Tujunga series, and river wash materials all of which are quite absorp- tive. There is no municipal development in this basin. Only about 2 percent of the area is devoted to agriculture, and the remaining 98 percent is largely in a natural state. The local water suppl}^; utilized almost entirely through pumping from ground water, originates in precipitation on valley lands, inflow from 1,550 acres of mountains directly tributary to the basin, and sur- face inflow from Rialto and Bunker Hill Basins in Lytle Creek and Cajon Creek, respectively. Interconnection between Lytle and Bunker Hill Basins is such that underflow may be in one direction at one point, and the opposite at another. Net flow may also be in one direction at one time and the reverse at another. Imported water, part of which passes through the basin, provides a relatively large addition to the supply. A considerable part of the surface inflow flows out into Bunker Hill Basin, and water is exported in large amount to Colton, Rialto, Bunker Hill and Chino Basins. 190 DIVISION OF WATER RESOURCES Due to increased export in recent yesirs, average annual demand under present conditions is somewhat greater than mean annual supply. Because storage capacity is so limited that neither overdraft nor excess can continue for any considerable period of time, the average annual amount that can be exported under present conditions, without exceed- ing supply over a long-time cycle, is estimated herein. Evaluation of items required* for the estimate follows. Inflow Estimated annual surface inflow averages 9,510 acre-feet, 11,340 acre-feet and 12,100 acre-feet in the 32-, 21- and 11-year periods, respec- tively, as derived in Table 137. The estimate of annual inflow from 1,550 acres of mountains directly- tributary to the basin is based on the assumption that, if water is available, average consumptive use on the mountain area is 20 inches. The 11- and 21-year values are estimated to be 0.79 and 0.80 times the 32-year mean, respectively, these being the ratios between the 11- and 21-year averages and the 32-year mean discharge of Santa Ana River. Inflow on the surface from other basins includes a part of the surface outflow from Rialto and Bunker Hill Basins. It is assumed that only subsurface inflow is that indicated by note in Table 137. TABLE 137. SURFACE INFLOW TO LYTLE BASIN Average annual for 32-year period, 1904-05 to 193 5-36, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-3 8, inclusive (Acre-feet) 32-year 21-year 11-year period period period From directly tributary mountains Estimated » 1,360 1,080 1,070 From other basins Rialto 6,580 7,770 8,390 Bunker Hill 1,570 2,490 2,640 Total •" 9,510 11,340 12,100 * Includes a relatively small amount of underflow. « Import In Table 138 estimated values of imports of water from both gravity and pumped sources in Rialto Basins for each year since 1927-28 are presented. No sewage is imported. Values of import given include releases from Fontana Power House for spreading in Lytle Creek chan- nel. During the ll-j^ear period an annual average of 10,520 acre-feet was imported. The amount of gravity water imported depends to some extent upon the amount available. Diversions to and releases from the power house have been measured since 1918-19 and 1926-27 respectively. Average * Values of change in storage and precipitation, also required, are presented in Tables 5 and 7. SOUTH COASTAL BASIN INVESTIGATION 191 annual release from the power house back to Lytle Creek channel is assumed to equal the average power diversion from Lytle Creek for the 21-year period, multiplied by the ratio between amount released and amount diverted since 1926-27. Assuming the import of pumped water equal to the average for the four-year period, 1941-12 to 1914-45, inclusive, estimated long-time mean import to L}i;le Basin under present conditions totals 10,620 acre-feet annually. TABLE 13 8. IMPORT TO LYTLE BASIN Year Acre- feet Year Acre-feet Year Acre-feet 1927-28 10,800 1928-29 7,060 1929-30 9,270 1930-31 7,850 1931-32 11,930 1932-33 9,830 1933-34 7,140 1934-35 12,700 1935-80 6,530 1936-37 15,940 1937-38 16,690 1938-39 11,370 1939-40 11,170 1940-41 18,950 1941-42 12,540 1942-43 12,990 1943-44 12,400 1944-45 13,110 Consufttptive Use In Table 139 estimates of consumptive use based on culture surveys conducted by the Division of Water Resources in 1932 and 1942 are presented. Unit consumptive use is discussed in Chapter V. The many small channels of Lytle Creek cover virtually the entire area. Largely because of this there is no municipal development, the acreage devoted to agriculture is small, and most of the area remains in its natural state. Cover ranges from moderately heavy brush to grass. TABLE 139. ESTIMATED AVERAGE ANNUAL CONSUMPTIVE USE IN LYTLE BASIN Type of culture Unit con- sumptive 1932 1942 use, feet Acres Acre-feet Acres Acre-feet Valley area Avocado and citrus Deciduous Unirrigated 32-year period 21-year period 11-year period Subtotal 32-year period 21-year period 11-year period Mountain area Deciduous Grand total 32-year period 21-year period 11-year period 2.5 63 158 63 158 2.3 42 97 27 62 3,843 , , 3,858 1.7 _—..— — .^ 6,559 1.707 6,586 1.693 6,506 3,948 3,948 — ^^ 1 1 ,^_ .-^^^ 6,779 _ .- — — 6,806 0.6 115 6,761 69 4,063 3,948 6,830 6,779 6,806 » Difference between irrigated culture and natural vegetation. 192 DIVISION OF WATER RESOURCES Historical Export In Table 140 estimated exports of water for eacli year since 1927-28 are presented. There is no sewage outflow. Water is exported to Chino, Rialto, Colton and Bunker Hill Basins. Export includes both water pumped from the basin and imported water. During the 11-year period an annual average of 13,450 acre-feet was exported. TABLE 140. EXPORT FROM LYTLE BASIN Year Acre-feet Year Acre-feet Year Acre-feet 1927-28 19,500 1933-34 15,460 1939-40 17,420 1928-29 19,830 1934-35 10,710 1940-41 10,300 1941-42 18,370 1930-31__ 13,970 1936-37 9,020 1942-43 18,560 1931-32 9,260 1937-38 9,270 1943-44 16,770 1932-33 11,630 1938-39 17,230 1944-45 19,180 Surface Outflow Outflow on the surface includes part of the inflow from directly tributary mountains, part of that from other basins, part of the Fontana Power House release and runoff originating in precipitation on the over- lying valley. Daily discharges in East and West Branches of Lytle Creek have been measured at Stations 17980 and 17982, respectively, since January, 1929. Fontana Union Water Company has measured daily discharges in Lytle Creek at Station 18769 continuously since March 5, 1938, and intermittently at Station 18767, at the basin boundary, since that date. These latter data have been used to determine a curve which represents average percolation rates between the basin boundary and Foothill Boule- vard. It is assumed that there was little or no percolation below Foothill Boulevard, since it is close to the limit of the pressure area. Surface outflow from the basin, for the period from January, 1929, through March 4, 1938, is estimated by use of the above percolation curve and daily discharges at gaging stations 17980 and 17982. Surface outflow subsequent to March 4, 1938, for days when not measured at Station 18767, is estimated by use of the percolation curve and daily discharges measured at Station 18769. Surface outflow prior to January, 1929, is estimated from measured and estimated yearly runoff in Lytle Creek at Station 19449, using rela- tionship of outflow to runoff established during subsequent years. Yearly runoff at Station 19449, prior to beginning of record in 1918-19, is estimated by comparison with San Antonio Creek. On this basis, average annual surface outflow for the 32-year period is estimated to be 2,210 acre-feet ; for the 21-year period, 4,060 acre-feet ; and for the 11-year period, 5,430 acre-feet. Subsurface Outflow Assuming that all items involved have been correctly evaluated, subsurface outflow dtiring the 11-year base period must, in accordance with principles set forth in Chapter V, have averaged 590 acre-feet annually, as derived in Table 141. SOUTH COASTAL BASIN INVESTIGATION 193 TABLE 141. ESTIMATED AVERAGE ANNUAL SUBSURFACE OUTFLOW FROM LYTLE BASIN DURING THE 11-YEAR PERIOD, 1927-28 TO 1937-3 8, INCLUSIVE Acre- feet Water entering basin Precipitation 7,140 Surface inflow 12,100 Import 10,520 Subtotal 29,760 Water leaving basin on the surface Surface outflow 5,430 Export 13,450 Consumptive use 0,830 Increase in storage 3,460 Subtotal 29,170 Subsurface Outflow — to Bunker Hill Basin 590 Long-time Mean Amount Available for Export The hydrologic equation used in the foregoing article applies equally well in any period. If safe yield of the basin is fully utilized, with neither excess nor overdraft, net change in storage over a cycle of long-time mean supply is zero. Assuming that subsurface outflow is the same for all periods, all items involved, except export, have been evaluated for both 32- and 21-year cycles. Assuming the 21-year period to represent the cycle of long-time mean supply, estimated long-time mean annual amount available for export is 17,760 * acre-feet, as derived in Table 142. If the 32-year values are substituted the derived value is 17,750 acre-feet. TABLE 142. ESTIMATED AVERAGE ANNUAL AMOUNT AVAILABLE FOR EXPORT FROM LYTLE BASIN UNDER PRESENT CONDITIONS ASSUMING THE 21 -YEAR PERIOD, 1922-23 TO 1942-43, INCLUSIVE, TO BE ONE OF LONG-TIME MEAN SUPPLY (Acre-feet) Estimated long-time mean annual under present conditions Supply to basin Precipitation 7,260 Import 10,620 Surface inflow 11,340 Subtotal 29,220 Demand on basin, excluding export Consumptive use 6,810 Surface outflow 4,060 Subsurface outflow 590 Subtotal 11,460 Available for Export 17,760 * There is some evidence tending to justify establisliing the boundary between Lytle and Rialto Basins west of Lytle Creek throughout its length. It is estimated that 30,600 acre-feet of water per year is available for export from the area which would constitute Lytle Basin if this were done. Calculated overdraft on Rialto Basin would not be affected by the change. 13—71061 194 DIVISION OF WATER RESOURCES DEVIL CANYON BASIN (24) Devil Canyon Basin is located in the north central portion of Upper Santa Ana Valley, and covers about 9.9 square miles. It is bounded on the south and southwest by Bunker Hill Basin and Shandin Hills, on the northwest by Lower Cajon Basin, and on the north and northeast by San Bernardino Mountains. Topography is irregular, the result of alternate deposition and cutting by numerous small, flashy streams enter- ing from mountains on the northeast. Slope is generally to the south and averages about 200 feet per mile, being steeper immediately adjacent to the mountains. Elevations range from 1,285 to more than 2,200 feet above sea level. Soils covering this basin are mostly lighter members of the Hanford and Tujunga series, with a few small areas of light Pla- centia and Holland soils. All are quite absorptive. Municipal develop- ment occupies only about 4 percent of the area, about 6 percent is devoted to agriculture, and the remaining 90 percent is largely in a natural state. The local water supply, utilized both through pumping from ground water, and by diversion from surface streams, originates in precipitation on the vallev, inflow from 17,700 acres of mountains and 720 acres of hills direct! V tributarv to the basin, and inflow on the surface from Lower Cajon Basin. There is no import of water or sewage. A considerable part of the surface inflow and a smaller part of the precipitation on the valley flows out into Bunker Hill Basin, together with large underflow, and water is exported in relatively large amount to the same basin. Long-time mean annual supply entering Devil Canyon Basin under present conditions is materially greater than present annual demand. Along its south boundary, however, there is no effective barrier to under- flow into Bunker Hill Basin. For this reason it is assumed that water, which might constitute an excess if such a barrier existed, soon leaves the basin as underflow, and it is the long-time mean amount of this subsur- face outflow to downstream basins which is estimated herein. Evaluation of items required * for the estimate follows. Inflotv Annual inflow from directly tributary mountain area above gaging stations at which flow has been measured during a part of each period, is tabulated below. The 32-3^ear mean values for Waterman Canyon Creek and Strawberry Creek were computed by comparison with Santa Ana River. Values for all three periods for Devil Canyon Creek were estimated by comparison with Waterman Canyon Creek. Mean annual infloic'^ in acre-feet 32-year 21-year 11-year Stream Station period period period Devil Canyon Creek 19569 2,810 2,180 2,030 Waterman Canvon Creek 18820 2,600 1,930 1,790 Strawberry Creek 18832 4,430 3,520 3,040 Total 9,840 7,630 6,860 * Including diversions. * Values of change in storage and precipitation, also required, are presented in Tables 5 and 7. SOUTH COASTAL BASIN INVESTIGATION 195 The estimate of 32-year mean annual inflow from 5,660 acres of mountains and 720 acres of hills directly tributary to the basin, and downstream from gaging stations at which the above tabulated inflow was measured is based on the assumption that average consumptive use on mountain area is 20 inches, and that on hill area 19 inches. Average inflow from the mountains during the 11-year period is estimated to be 0.79 times the 32-year mean, this being the ratio between 11- and 32-mean discharge of Santa Ana River. That from the hills is estimated to be 0.99 times the 32-year mean, being proportional to precipitation on the area represented by the San Bernardino Group. Corresponding ratios for the 21-year period are 0.80 for mountains and 1.01 for hills.* A small part of surface outflow from Lower Cajon Basin enters Devil Canyon Basin. It is assumed that the only subsurface inflow is that indicated by note in the table. TABLE 143. SURFACE INFLOW TO DEVIL CANYON BASIN Average annual for 32-year period, 1904-05 to 1935-36, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38, inclusive (Acre-feet) 32-year 21-year 11-year period period period From directly tributary mountains Measured during part of period 9,840 Estimated « 2,330 From directly tributary hills Estimated'' 240 From other basins Lower Cajon 2,060 Total 14,470 11,400 10,590 ■ Includes a relatively small amount of underflow. Consufnptive Use In Table 144 estimates of consumptive use based on culture surveys conducted by the Division of Water Resources in 1932 and 1942 are presented. Unit consumptive use is discussed in Chapter V. A relatively small part of the area is used. The City of San Bernardino extends into the easterly end, and something less than 6 percent of the total is devoted to irrigated agriculture. Some unirrigated lands are used for spreading, grapes occupy a part, and most of the remainder is covered with brush. * If inflow from hills is assumed to follow the same regimen of flow as Santa Ana River, average for both 21- and 11-year periods is 190 acre-feet. 7,630 6,860 1,860 1,840 240 240 1,670 1,650 196 DIVISION OF WATER RESOURCES TABLE 144. ESTIMATED AVERAGE ANNUAL CONSUMPTIVE USE IN DEVIL CANYON BASIN Unit con- Type of culture sumptive 1932 1942 use, feet Acres Acre-feet Acres Acre-feet Valley area Garden and field Avocado and citrus Deciduous Domestic and industrial. Unirrigated 32-year period 21-year period 11-year period Subtotal 32-year period 21-year period 11-year period __. Mountain area Avocado and citrus Grand total 32-year period 21-year period 11-year period 1.4 30 42 125 175 2.5 227 568 212 530 2.3 125 288 35 80 1.8 188 338 263 473 5,745 5,680 ^ ,_ ,,, 1.7 .^ 9,656 1.707 ^^__ 9,696 1.693 9,726 6,315 10,962 0.9' 22 20 6,337 10,982 6,315 _ *- — ^ — 10,914 10,954 22 20 6,337 10'934 10,974 " Difference between irrigated culture and natural vegetation. Export In Table 145 estimated exports of water to Bunker Hill Basin for each year since 1927-28 are presented. There is no sewage outflow. Dur- ing the 11-year period an annual average of 1,930 acre-feet of water was exported. Estimated average annual export of water under present con- ditions is 3,170 acre-feet, equal to the average for the four-year period, 1941-42 to 1944-45, inclusive. TABLE 145. EXPORT FROM DEVIL CANYON BASIN Year Acre- feet Year Acre-feet Year Acre-feet 1927-28 2,300 1928-29 — — 1,900 1929-30 2,380 1930-31 1,630 1931-32 1,920 1932-38 2,080 1933-34 1,400 1934-35 1,140 1935-36 1,280 1936-37 2,300 1937-38 2,920 1938-39 3,140 1939-40 2,620 1940-41 3,140 1941-42 2,140 1942-43 3,210 1943-44 3,660 1944-45 3,670 Surface Outflow Outflow on the surface includes part of the inflow from directly tributary mountains and hills, part of that from Lower Cajon Basin, and runoff originating in precipitation on the overlying valley. It is estimated to average 5,200 acre-feet, 4,100 acre-feet and 4,250 acre-feet annually in the 32-, 21- and 11-year periods, respectively, as derived in Table 146. SOUTH COASTAL BASIN INVESTIGATION 197 Inflow from mountains directly tributary to this basin is well dis- tributed in several streams, the larger being Devil Canyon, Waterman Canyon and Strawberry Creeks. None of the channels are paved, and there are spreading grounds on Devil Canyon and Waterman Canyon Creeks. DEVIL CANYON CREEK To estimate historic outflow in this stream during the 11-year period, 30 second-feet, assumed to be spread, is first subtracted from the measured daily discharge at Station 19569. Estimated percolation below the spread- ing grounds, using a standard curve which results in total percolation up to 23 second-feet, is then subtracted from the discharge below the spread- ing grounds. Average annual outflow during the 11-year period, as estimated, is 160 acre-feet. Under a plan which contemplates the early construction of an over- flow channel through the low hills to the southwest, percolation below the spreading grounds is virtually eliminated. Outflow during each year since 1933-34, when measurements of diversion above the gaging station started, is estimated by subtracting 30 second-feet from the discharge at the station. To estimate outflow in earlier years the relationships (1) between annual outflow and net annual flow at the gaging station, and (2) between annual diversions and full natural annual inflow, as estab- lished since 1933-34, are used. Full natural inflow in the earlier years is estimated by comparison with Waterman Canj^on Creek and Santa Ana River, diversions determined from relationship (2), net discharges at the station obtained by subtraction, and outflow finally derived from relationship (1). Estimated 32- and 21-year mean annual outflows so obtained are 240 and 150 acre-feet respectively. WATERMAN CANYON CREEK Discharge of Waterman Canyon Creek has been measured at Station 18820 since 1920-21. Assuming that 12 second-feet was diverted for spreading and direct use, estimated 11-year average annual outflow was 440 acre-feet. The spreading grounds have been enlarged in recent years, and are now being extended further to provide flood protection as well as water conservation. To estimate outflow from the basin under present conditions during 32- and 21-year periods, it is arbitrarily assumed that 150 second- feet are diverted to spreading, and that all discharge in excess of that amount passes from the basin. Using the relationship between annual inflow and outflow established during the period of record, and estimated values of run-off for years prior to 1920-21 computed by comparison with Santa Ana River, outflow for years prior to beginning of record is esti- mated. The resulting mean annual outflow is 60 and 30 acre-feet in the 32- and 21-year periods respectively. STRAWBERRY CREEK Discharge of Strawberry Creek has been measured at Station 18832 since 1920-21. Allowing for a small diversion by Del Rosa Water Com- pany, and using a percolation curve which results in total percolation up to three second-feet, 21- and 11-year average annual outflows are estimated to be 1,690 and 1,460 acre-feet, respectively. Determining inflow 198 DIVISION OF WATER RESOURCES for years of no record by comparison with Santa Ana Kiver, and using the relationship between inflow and outflow established during years of record, estimated 32-year mean annual outflow is 2,240 acre-feet. OTHER SOURCES Estimated outflow from other sources includes 90 percent of the inflow from 400 acres and 50 percent of that from 5,270 acres of directly tributary mountains, 75 percent of that from all hills directly tributary to the basin, 50 percent of that from Lower Cajon Basin, and 2 percent of precipitation on overlying valley land. TABLE 146. SURFACE OUTFLOW FROM DEVIL CANYON BASIN Average annual for 32-year period, 1904-05 to 193 5-36, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38, inclusive (Acre-feet) S2-year 21-year 11-year period period period Estimated, originating in Measured mountain streams ^ 2,540 1,870 2,060 Directly tributary mountains 1,210 970 950 Directly tributary hills 180 180 180 Inflow from other basins 1,030 840 820 Precipitation on valley land 240 240 240 Total 5,200 4,100 4,250 » From daily discharges, spreading and percolation. Subsurface Outflow In accordance with principles set forth in Chapter Y, historic average annual subsurface outflow during the 11-year period, and present long-time mean annual subsurface outflow under two assump- tions as to cycle of long-time mean supply, are derived in Table 147. Since a relatively greater amount of stream-flow data is available during the 21-year period, estimated long-time mean subsurface outflow under present conditions is 5,160 acre-feet. TABLE 147. ESTIMATED SUBSURFACE OUTFLOW FROM DEVIL CANYON BASIN Average annual for 32-year period, 1904-05 to 193 5-36, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38, inclusive (Acre-feet) 32-year 21-year 11-year period period period Water entering basin Precipitation 11,890 12,000 11,800 Surface inflow 14,470 11,400 10,590 Subtotal 26,360 23,400 22,390 Increase in storage 1,280 Water leaving basin on surface Surface outflow 5,200 4,100 4,250 Export : 3,170 3,170 1,930 Consumptive use 10,930 10,970 10,980 Subtotal 19,300 18,240 18,440 Subsurface Outflow — to Bunker Hill Basin 7,060 5,160 3,950 SOUTH COASTAL BASIN INVESTIGATION 199 YUCAIPABASIN (25a) Yucaipa Basin is located in the easterly portion of Upper Santa Ana Valley, and covers about 28 square miles. It is bounded on the southwest by San Timoteo Basin, on the northwest by Bunker Hill Basin and granitic hills, on the northeast by San Bernardino Mountains, and on the southeast and south by Beaumont Basin. Topography is irregular, cut by numerous deeply incised channels. The slope to the southwest averages about 250 feet per mile. Elevations above sea level range from 2,000 to 5,000 feet. Soils are mostly lighter members of the Placentia series, with relatively narrow areas of light Hanford soils along stream channels. While Placentia soils are less pervious than those of the Han- ford series, they are still quite absorptive. Municipal development occu- pies only about 2 percent of the area, about 26 percent is devoted to agriculture, and the remainder is in a more or less natural state. The local water supply, utilized to a minor extent through diversion from surface streams, but more through pumping from ground water, originates in precipitation on the valley, and inflow from 4,260 acres of mountains and 8,360 acres of hills directly tributary to the basin. There is no import of water or sewage. A considerable part of the surface inflow and precipitation flows out into San Timoteo Basin, together with some underflow, and water is exported in relatively large amount to the same basin. In this basin, long-time mean annual net supply under present con- ditions is less than present annual demand, so an overdraft exists. Evaluation of items required * to estimate its amount follows. Inflow Estimated annual surface inflow averages 5,960 acre-feet, 5,270 acre- feet and 5,200 acre-feet in the 32-, 21- and 11-year periods, respectively, as derived in Table 148. The estimate of 32-year mean annual inflow from 4,260 acres of mountains and 8,360 acres of hills directly tributary to the basin is based on the assumption that, if water is available, average consumptive use on mountain area is 22 inches and that on hill area 18 inches, inflow values however being never less than 7 percent of precipitation on moun- tains and 9 percent of that on hills. The 11 -year value for mountains is estimated to be 0.79 times the 32-year mean, this being the ratio between 11- and 32-year mean discharge of Santa Ana River. That for the hills is estimated to be 0.99 times the 32-year mean, being proportional to pre- cipitation on the area represented by the San Bernardino Group. Cor- responding ratios for the 21-year period are 0.80 for the mountains and 1.01 for the hills, t Subsurface inflow is assumed to be only that indicated by note in Table 148. * Values of change in storage and precipitation, also required, are presented in Tables 5 and 7. t If inflow from the hills is assumed to follow the same regimen of flow as Santa Ana River, estimated annual inflow from that source is 1,920 and 1,900 acre-feet during 21- and 11-year periods, respectively. 200 DIVISION OF WATER RESOURCES TABLE 148. SURFACE INFLOW TO YUCAIPA BASIN Average annual for 3 2-year period, 1904-0 5 to 193 5-3 6, inclusive; 21 -year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-3 8, inclusive (Acre-feet) S2-year period 21-year period 11-year period Estimated, originating in Directly tributary mountains 3,560 Directly tributary hills 2.400 Total" 5,960 2.850 2,420 5,270 2,820 2,380 5,200 ■ Includes a relatively large but undetermined amount of underflow. Consumptive Use In Table 149 estimates of consumptive use based on culture surveys conducted bv the Division of Water Resources in 1932 and 1942 are presented. Unit consumptive use is discussed in Chapter V, Domestic development is relatively small and industry negligible. Because of the climate at this altitude, deciduous orchards and gardens constitute the principal crops. Cover on unirrigated lands ranges from heavy brush to grass and weeds. TABLE 149. ESTIMATED AVERAGE ANNUAL CONSUMPTIVE USE IN YUCAIPA BASIN Type of culture Valley and folded area Garden and field Avocado and citrus Deciduous Alfalfa Domestic and industrial. Unirrigated 32-year period 21-year period 11-year period Subtotal 32-year period 21-year period __. 11-year period — Hill area Avocado and citrus Deciduous Subtotal Grand total 32-year period __ 21-year period __ 11-year period __ Unit con- sumptive 1932 1942 use, feet Acres Acre-feet Acres Acre-feet 1.4 272 381 1,017 1.424 2.7 209 564 404 1,091 2.3 4,362 10,033 3,017 6,939 3.0 71 218 96 288 1.8 195 351 390 702 ___ 12.521 12,706 1.5 , , ^ — . — -_^ 19,059 1.506 19,135 1.494 __. 18,706 17,630 17,630 1.2" 0.8' 17 130 147 30,248 20 104 124 17 135 152 17,777 17,782 30,372 29,503 29,579 20 108 128 29,631 29,707 • Difference between irrigated culture and natural vegetation. SOUTH COASTAL BASIN INVESTIGATION 201 Export In Table 150 estimated exports of water to San Timoteo Basin for each year since 1927-28 are presented. There is no sewage outflow. Dur- ing the 11-year period, an annual average of 1,440 acre-feet of water was exported. Estimated average annual export of water under present conditions is 1,420 acre-feet, equal to the average for the four-year period, 1941-42 to 1944-45, inclusive. TABLE 150. EXPORT FROM YUCAIPA BASIN Year Acre-feet Year Acre-feet Year Acre-feet 1927-28 1,410 1933-34__^ 1,670 1939-40 1,580 1928-29 1,490 1934-35 1,140 1940-41 1,240 1929-30 1.560 1935-36 1,560 1941-42 1,520 1930-31 1,600 1936-37 1,330 1942-43 1,400 1931-32 1,220 1937-38 1,370 1943-44 1,350 1932-33 1,470 1938-39 1,430 1944-45 1,400 Surface Outflow Outflow on the surface includes part of the inflow from directly tributary mountains and hills and runoff originating in precipitation on the overlying valley. It is estimated to average 1,470 acre-feet, 1,320 acre-feet and 1,300 acre-feet annually in the 32-, 21- and 11-year periods, respectively, as derived in Table 151. Geological investigations indicate that a considerable part of the estimated inflow to this basin from the mountains reaches the valley as underflow. Surface flow is distributed in several small streams which, except those tributary to Bunker Hill Basin, flow from six to ten miles across Yucaipa Basin. None of these stream channels are paved, and there is consideraMe percolation opportunity. Directly tributary hills are also for the most part some distance from the basin boundary. It is estimated that outflow from this basin includes 90 percent of the inflow from 1,120 acres of mountains and 140 acres of hills adjacent to Bunker Hill Basin, 10 percent of the inflow from remaining directly tributary mountains and hills, 5 percent of the precipitation on 2,320 acres of basin land classified as folded, and 1 percent of the precipitation on other valley land. TABLE 151. SURFACE OUTFLOW FROM YUCAIPA BASIN Average annual for 32-year period, 1904-05 to 1935-36, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38, inclusive (Acre-feet) 32-year 21-year 11-year period period period Estimated, originating in Directly tributary mountains 790 640 630 Directly tributary hills 260 260 250 Precipitation on valley and folded area 420 420 420 Total 1,470 1,320 1,300 202 DIVISION OF WATER RESOURCES Overdraft Assuming that the 21-year period is the cycle of long-time mean supply, estimated annual overdraft is 1,150 acre-feet, as derived in Table 152. If the 32-year mean values are substituted in the table the derived value is 790 acre-feet. TABLE 15 2. ESTIMATED ANNUAL OVERDRAFT IN YUCAIPA BASIN UNDER PRESENT CONDITIONS ASSUMING THE 21 -YEAR PERIOD, 1922-23 TO 1942-43, INCLUSIVE, TO BE ONE OF LONG-TIME MEAN SUPPLY (Acre-feet) Estimated Actual long-time 11-year mean annual hase under period present average Differ- conditions annual ence Average annual drop in storage during base period 2,350 Items tending to increase the drop Consumptive use 29,710 30,370 — 660 Surface outflow 1,320 l,.30O 20 Export 1,420 1,440 —20 Subtotal to be added — 660 Items tending to decrease the drop Precipitation 28,950 28,480 470 Surface inflow 5,270 5,200 70 Subtotal to be subtracted 540 Overdraft 1,150 Subsurface Outflow Assuming that all items involved have been correctly evaluated, subsurface outflow during the 11-year base period must, in accordance with principles set forth in Chapter V, have averaged 2,920 acre-feet annuallj^, as derived in Table 153. TABLE 15 3. ESTIMATED AVERAGE ANNUAL SUBSURFACE OUTFLOW FROM YUCAIPA BASIN DURING THE 11-YEAR PERIOD, 1927-28 TO 1937-38, INCLUSIVE Acre-feet Water entering basin Precipitation 28,480 Surface inflow 5,200 Water coming from storage in basin 2,350 Subtotal 36,030 Water leaving basin on surface Surface outflow 1,300 Export 1,440 Consumptive use 30,370 Subtotal 33,110 Subsurface Outflow — to San Timoteo Basin 2,920 SOUTH COASTAL BASIN INVESTIGATION 203 BEAUMONT BASIN (25b) * Beaumont Basin is located in the extreme east end of Upper Santa Ana Valley, and covers about 31 square miles. It is bounded on the west by San Timoteo Basin, on the north and northwest by Yucaipa Basin, on the north by San Bernardino Mountains, on the southeast by the watershed of Whitewater River, and on the south by the watershed of San Jacinto River. Topography is irregular with deeply incised chan- nels. Slope is to the south and southwest, and ranges from 100 to 600 feet per mile. Elevations above sea level range from 2,300 to 5,500 feet. Soils are about equally divided between lighter members of the Placentia and Hanford series, both of which are quite absorptive. Municipal develop- ment occupies only about 3 percent of the area, about 13 percent is devoted to agriculture, and the remaining 84 percent is in a more or less natural state. The local water supply, utilized through diversion from surface streams, and through pumping from ground water, originates in pre- cipitation on the valley, and inflow from 1,550 acres of mountains and 8,320 acres of hills directly tributary to the basin. There is no import of water or sewage. A considerable part of the surface inflow and precipitation flows out into San Timoteo Basin, together with some underflow. Water is exported in relatively large amount to San Timoteo Basin, from which the major portion is re-exported to San Jacinto Valley. Under terms of the Yucaipa Judgment,* the amount of water that may be pumped for export from the basin is dependent upon elevation of the water table at Well No. E-233f, Plate 15, decreasing as the water table drops, and vice versa. Thus a possible overdraft is counterbalanced by decreased export and a possible excess by a corresponding increase. It is therefore considered that there is neither excess nor overdraft in the basin and the average annual amount that can be exported without caus- ing an overdraft, under present conditions over a long-time cycle of sup- ply, is estimated herein. While it is believed that the result obtained by another method, described in the closing paragraphs of this section is probably more accurate, evaluation of items required t for an estimate through the use of the hydrologic equation follows. Inflotv Estimated annual surface inflow averages 6,100 acre-feet, 5,750 acre-feet and 5,650 acre-feet in the 32-, 21- and 11-year periods, respec- tivelv, as derived in Table 154. The estimate of 32-year mean annual inflow from 1,550 acres of mountains and 8,320 acres of hills directly tributary to the basin is based on the assumption that, if water is available, average consumptive use on mountain area is 22 inches, and that on hill area 17 inches. Eleven-year average inflow from mountains is estimated to be 0.79 times the 32-year mean, this being the ratio between 11- and 32-year mean discharge of Santa Ana River. That from the hills is 0.99 times the 32-year mean, being proportional to precipitation on the area represented by the San * Case No. 24570, San Bernardino County, May 7, 1929. t Values of change in storage and precipitation, also required, are presented in Tables 5 and 7. 204 DIVISION OF WATER RESOURCES Bernardino Group. Corresponding ratios for the 21-year period are 0.80 for mountains and 1.01 for hills. t Subsurface inflow, other than that indicated by note in Table 154, is negligible. TABLE 154. SURFACE INFLOW TO BEAUMONT BASIN Average annual for. 32-year period, 1904-05 to 1935-36, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38, inclusive (Acre-feet) 32-year 21-year 11-year period period period Estimated, originating in Directly tributary mountains 1,940 1,550 1,530 Directly tributary hills 4,160 4,200 4,120 Total « 6,100 5,750 5,650 * Includes a relatively large but undetermined amount of underflow. Consumptive Use In Table 155 estimates of consumptive use based on culture surveys conducted by the Division of Water Resources in 1932 and 1942 are presented. Unit consumptive use is discussed in Chapter V. The City of Beaumont is the only municipal development. Because of the altitude, deciduous orchards constitute the principal irrigated crop. Cover on unirrigated lands ranges from heavy brush and small trees at higher levels, to grass and weeds where the altitude is less. TABLE 15 5. ESTIMATED AVERAGE ANNUAL CONSUMPTIVE USE IN BEAUMONT BASIN Unit con- sumptive 1932 1942 Type of culture use, feet Acres Acre-feet Acres Acre-feet Valley and folded area Garden and field 1.4 86 120 176 246 Deciduous 2.3 2,579 5,932 2,384 5,483 Alfalfa 3.0 3 9 18 54 Irrigated grass 3.0 5 15 Domestic and industrial 1.8 519 934 599 1,078 Unirrigated 16,472 16,477 32-year period 1.6 26,363 21-year period 1.606 26,462 11-year period 1.594 26,256 Subtotal 19,659 19,659 32-year peiiod 33,239 21-year period 33,338 11-year period — 33,251 Hill area Deciduous 0.9" 41 37 41 37 Grand total 19,700 19,700 . 32-year period — — 33,276 21-year period 33,375 11-year period 33,288 » Difference between irrigated culture and natural vegetation. t If inflow from hills is assumed to follow the same regimen of flow as the Santa Ana River, estimated annual inflow is 3,330 and 3,290 acre-feet during the 21- and 11-year periods, respectively. SOUTH COASTAL BASIN INVESTIGATION 205 Historical Export In Table 156 estimated exports of water from pumped sources to San Timoteo Basin for each j^ear since 1927-28 are presented. There is no sewage outflow. During the 11-year period an annual average of 2,620 acre-feet was exported. TABLE 156. EXPORT FROM BEAUMONT BASIN Year Acre- feet Tear Acre-feet Year Acre- feet 1927-28 3,370 1933-34 2,680 1939-40 2,050 1928-29 3,520 1934-35 2,120 1940-41 1,820 1929-30 2,810 1935-36 2,250 1941-42 2,340 1930-31 2,950 1936-37 1,810 1942-43 2,270 1931-32 2.550 1937-38 1,990 1943-44 2,090 1932-33 2,740 1938-39 2,180 1944-45 1,740 Surface Outflow Outflow on the surface includes part of the inflow from directly tributary mountains and hills, and runoff originating in precipitation on the overlying valley. It is estimated to average 1,090 acre-feet, 1,070 acre-feet and 1,040 acre-feet annually in the 32-, 21- and 11-year periods, respectively, as derived in Table 157. The area of mountains directly tributary to the basin is not large, and geological investigations indicate that a considerable part of the estimated mountain inflow enters the valley as underflow. The remainder flows, principally in unpaved channels of Little San Gorgonio and Noble Creeks, a distance of 10 miles or more southward across the alluvium to San Timoteo Creek, near the south boundary of the basin. Tributary hills are also for the most part some distance from the boundary. It is esti- mated that outflow from this basin includes 10 percent of inflow from directly tributary mountains and hills, 5 percent of precipitation on 2,390 acres of land classified as folded, and 1 percent of precipitation on valley land within the basin. TABLE 15 7. SURFACE OUTFLOW FROM BEAUMONT BASIN Average annual for 32-year period, 1904-05 to 1935-36, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38, inclusive (Acre-feet) 32-year 21-year 11-year period period period Estimated, originating in Directly tributary mountains 190 160 150 Directly tributary hills 420 420 410 Precipitation on valley and folded laud 480 490 480 Total 1,090 1,070 1,040 Subsurface Outflow Assuming that all items involved have been correctly evaluated, subsurface outflow during the 11-year base period must, in accordance with principles set forth in Chapter V, have averaged 3,800 acre-feet annually, as derived in Table 158. 206 DIVISION OF WATER RESOURCES TABLE 158. ESTIMATED AVERAGE ANNUAL SUBSURFACE OUTFLOW FROM BEAUMONT BASIN DURING THE 11-YEAR PERIOD, 1927-28 TO 1937-3 8, INCLUSIVE Acre-feet Water entering basin Precipitation 34,360 Surface inflow 5,650 Water coming from storage in basin 740 Subtotal 40,750 Water leaving basin on surface Surface outflow . 1,040 Export 2,620 Consumptive use ; 33,290 Subtotal 36,950 Subsurface Outflow — to San Timoteo Basin 3,800 Long-time Mean Amotint Available for Export The hydrologic equation used in the foregoing article applies equally well in any period. Since there is considered to be neither excess nor overdraft, net change in storage over a cycle of long-time mean supply is zero. Assuming that subsurface outflow is the same in all periods, all items involved except export have been evaluated for both 32- and 21-year cycles. Assuming that the 21-3^ear period is the cycle of long-time mean supply and that the independently derived values are all correct, esti- mated long-time mean annual amount available for export is 2,420 acre- feet, as derived in Table 159. If 32-year mean annual values are substi- tuted, the value derived is 2,550 acre-feet. TABLE 159. ESTIMATED AVERAGE ANNUAL AMOUNT AVAILABLE FOR EXPORT FROM BEAUMONT BASIN UNDER PRESENT CONDITIONS ASSUM- ING THE 21-YEAR PERIOD, 1922-23 TO 1942-43, INCLUSIVE TO BE ONE OF LONG-TIME MEAN SUPPLY (Acre-feet) Est una ted long-time mean annual under present conditions Supply to basin Precipitation 34,920 Surface inflow 5,750 Subtotal 40,670 Demand on basin, excluding export Consumptive use 33,380 Surface outflow 1,070 Subsurface outflow : 3,800 Subtotal — 38,250 Available for Export 2,420 SOUTH COASTAL BASIN INVESTIGATION 207 However, throiio^hout the greater portion of the basin, including the area near index well E-233f, no net rise in ground water level has occurred during the period 1936-37 to date, even though precipitation has averaged 23 percent greater than the long-time mean and export averaged only a little more than 2,000 acre-feet per year. This indicates that the value of export which results in no overdraft, i.e. no drop in ground water level during a period of mean supply must be less than 2,000 acre-feet Assuming that Wells E-233f, E-240 and E-245, shown on Plate 20, are index wells for the basin as a whole, each foot change in water table elevation at the first represents 900 acre-feet, and at each of the others represents 600 acre-feet change in storage in the basin. If this assumption is correct, a reduction of export from an average of 2,480 acre-feet to between 1,500 and 1,600 acre-feet should have resulted in no net drop in water table elevation at the three wells during the 15-year period, 1927-28 to 1941-42, inclusive, in which precipitation averaged only 6 percent greater than the mean. From inspection of Table 159 it is apparent that relatively small errors in the estimated values of precipitation and consumptive use might result in considerable error in the value of export derived by the procedure shown there. On the other hand, the assumption that the drop which has occurred at the above three wells was as great over the entire basin is open to question. Until such time as experience provides a more dependable answer, permissible export from this basin, with conditions otherwise those of the present, is estimated to average 1,800 acre-feet annually. SAN TIMOTEO BASIN (26) San Timoteo Basin is located in the south central portion of Upper Santa Ana Valley, and covers about 45 square miles. It is bounded on the south by Reche Canyon Basin and the watershed of San Jacinto River, on the north by Bunker Hill Basin, and on the northeast and east by Yucaipa and Beaumont Basins. The folded formation which makes up a very large part of this basin results in broken, irregular topography. The slope, in the northwesterly direction of flow of San Timoteo Creek, is about 100 feet per mile. Elevations above sea level range from 1,075 to 2,400 feet. Soils covering the larger, folded portion of this basin are of the Placentia series. Narrow bottom lands along San Timoteo Creek are covered with more pervious Hanf ord sands and sandy loams. Municipal development occupies only about 2 percent of the area, about 20 percent is devoted to agriculture, and the remainder is largely in a natural state. The local water supply, utilized to a minor extent through diversion from surface streams and through pumping from ground water, orig- inates in precipitation on the valley, inflow from 2,130 acres of hills directly tributary to the basin, and inflow both underground and on the surface from Beaumont and Yucaipa Basins. Imported water provides a large part of the supply. A considerable part of the surface inflow and precipitation flows out into Bunker Hill Basin, together with large underflow, and water is exported in relatively large amount to San Jacinto River Valley. Since there is no effective barrier to underflow into Bunker Hill Basin, any apparent excess or deficiency in supply resulting from changes 208 DIVISION OF WATER RESOURCES in the relatively small extractions or large imports is soon compensated for by a corresponding increase or decrease in subsurface outflow. There- fore, neither excess nor overdraft is considered to exist, and long-time mean subsurface outflow under present condition is the value estimated herein. Evaluation of items required * to estimate its amount follows. Infiotv Estimated annual surface inflow averages 2,280 acre-feet, 2,210 acre-feet and 2,170 acre-feet in the 32-, 21- and ll-j^ear periods, respec- tively, as derived in Table 160. The estimate of inflow from 2,130 acres of directlj^ tributary hills is based on the assumption that 9 percent of precipitation thereon runs off.t Inflow on the surface from other basins includes all surface outflow from Beaumont Basin, and a large part of that from Yucaipa Basin. Subsur- face inflow includes the underflow out of Yucaipa and Beaumont Basins. During the 11-year period this averaged 2,920 and 3,800 acre-feet annu- ally from the respective basins, a total of 6,720 acre-feet. TABLE 160. SURFACE INFLOW TO SAN TIMOTEO BASIN Average annual for 32-year period, 1904-05 to 193 5-36, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38, inclusive (Acre-feet) 32-i/ear 21-year 11-year period period period From directly tributary hills Estimated" 250 260 260 From other basins Yucaipa 940 880 870 Beaumont 1,090 1,070 1,040 Total" 2,280 2,210 2,170 ■ Includes a relatively small amount of underflow. Iw^port In Table 161 estimated imports of water for each year since 1927-28 are presented. Tliere is- no import of sewage. Water is imported for use from both gravity and pumped sources in Bunker Hill, Yucaipa, and Beaumont Basins. During the 11-year period an annual average of 20,300 acre-feet was imported. The amount of water imported depends to some extent upon the amount of gravity water available. Present average annual import from Santa Ana River for export to San Jacinto Valley, which is based on ownership of Bear Valle}' Mutual Water Company stock, is assumed to equal the historic average for the 21-year period. Present average annual imrport for other purposes, partly from the river and partly pumped, is estimated to equal the average for the four-year period, 1941-42 to 1944-45, inclusive. Total present average annual import, so estimated, is 18,150 acre-feet. * Values of change in storage and precipitation, also required, are presented in Tables 5 and 7. t If inflow from hills is assumed to follow the same regimen as flow in Santa Ana River, estimated average annual inflow during the 21- and 11-year periods is 200 acre- feet. SOUTH COASTAL BASIN INVESTIGATION 209 Year TABLE 161. IMPORT TO SAN TIMOTEO BASIN Acre-feet Year Acre-feet Year Acre-feet 1927-28 21,840 1928-29 19,390 1929-30 18,310 1930-31 19,170 1931-32 22.650 1932-33 21,980 1933-34 19,190 1934-35 17,780 1935-36 20,720 1936-37 19,320 1937-38 22,900 1938-39 22,940 1939-40 20,350 1940-41 21.720 1941-42 18,900 1942-43 18,430 1943-44 18,660 1944-45 17,040 Consumptive Use In Table 162 estimates of consumptive use based on culture surveys conducted by the Division of Water Resources in 1932 and 1942 are presented. Unit consumptive use is discussed in Chapter V. All municipal development, and by far the greater part of irrigated culture lies within or adjacent to the City of Redlands. The rest is scattered along the narrow valley of San Timoteo Creek. Folded lands, almost entirely unirrigated, are for the most part covered with moderately heavy brush. TABLE 162. ESTIMATED AVERAGE ANNUAL CONSUMPTIVE USE IN SAN TIMOTEO BASIN Unit con- sumptive 1932 1942 Type of culture use, feet Acres Acre-feet Acres Acre-feet Valley and folded area Garden and field 1.4 70 98 80 112 Avocado and citrus 2.7 5,011 13,530 5,181 13,989 Deciduous 2.3 261 600 201 462 Alfalfa 3.0 178 534 198 594 Irrigated grass 3.0 62 186 77 231 Domestic and industrial 1.8 630 1,134 695 1,251 Unirrigated 22,804 22,584 32-year period 1.2 27,101 21-year period 1.217 27,485 11-year period 1.210 27,593 Subtotal - 29,016 '~^. 29,016 32-year period 43,740 21-year period 44,124 11-year period 43,675 Hill area Garden and field 0.2 =» 5 1 5 1 Avocado and citrus 1.5 '^ .30 45 30 45 Subtotal 35 4 6 35 46 Grand total - 29,0-51 _ 29,051 32-year period 43,786 21-year period 44,170 11-year period 43,721 * Difference between irrigated culture and natural vegetation. Export In Table 163 estimated exports of water from both gravity and pumped sources to San Jacinto Valley for each year since 1927-28 are presented. There is no sewage outflow. During the 11-year period an 14—71061 210 DIVISION OF WATER RESOURCES annual average of 3,800 acre-feet was exported. Present average annual export of gravity water is assumed to equal its historic average for the 21-year period, that of pumped water to equal its average for the four- year period, 1941-12 to 1941-45, inclusive. The total is 3,610 acre-feet. TABLE 163. EXPORT FROM SAN TIMOTEO BASIN Year Acre-feet Year Acre-feet Year Acre-feet 1927-28 4.070 1933-34 3,740 1939-40 3,530 1928-29 — 4,400 1934-35 2.940 1940-41 3,090 1929-30 3,690 1935-36 3,590 1941-42 3,930 1930-31 4,280 1936-37 3.020 1942-43 3,730 1931-32 4,060 1937-38 3,520 1943-44 3,770 1932-33 3,640 1938-39 3,840 1944-45 3,450 Surface Outflow Outflow on the surface includes part of the inflow from directly tributary hills, a part of that from Yucaipa and Beaumont Basins and runoff originating in precipitation on the overlying valley. It is estimated to average 2,230 acre-feet, 2,080 acre-feet and 1,740 acre-feet annually in the 32-, 21- and 11-year periods, respectiveh^ as derived in Table 164. Inflow from a little more than half of 2,130 acres of hill land directly tributarv to this basin flows westward for about five miles across recent alluvium in the northerly portion of the basin. Inflow from the remainder flows northward across about two miles of older folded formation into the narrow bottom lands of San Timoteo Creek, after which it traverses about two miles of recent alluvium bordering that stream. Discharge of San Timoteo Creek has been measured at Stations 18096 and 18128 since 1926-27. Unpublished data from the United States Geological Survey are available, from which estimates of outflow in that stream during prior years have been made. Estimated outflow originating below the gaging stations includes 90 percent of the inflow from directly tributary hills, 5 percent of the precipitation on the folded area, and 1 percent of the precipitation on valle}^ area within the basin. TABLE 1 64. SURFACE OUTFLOW FROM SAN TIMOTEO BASIN Average annual for 32-year period, 1904-05 to 1935-36, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-3 8, inclusive (Acre-feet) 32-year 21-year 11-year period period period Measured during part of period 1,720 1,540 1,200 Estimated, originating in Directly tributary hills 120 130 130 Precipitation on valley and folded lands 390 410 410 Total 2,230 2,080 1,740 Subsurface Outfloiv In accordance with principles set forth in Chapter V, historic aver- age annual subsurface outflow during the 11-year period, and present long-time mean annual subsurface outflow under two assumptions as to SOUTH COASTAL BASIN INVESTIGATION 211 cycle of long-time mean supply, are derived in Table 165. The difference betvi^een 32- and 21-year values is due primarily to difference in esti- mated precipitation for the two periods. Since mean precipitation for the 53-year period is less than the average during either 32- or 21-year cycles, annual subsurface outflow is estimated to be 13,960 acre-feet, this being the more conservative value. TABLE 165. ESTIMATED SUBSURFACE OUTFLOW FROM SAN TIMOTEO BASIN Average annual for 32-year period, 1904-05 to 193 5-36, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38, inclusive (Acre-feet) 32-year 21-year 11-year period period period Water entering basin Precipitation 36,440 37,490 37,030 Surface inflow 2,280 2,210 2,170 Subsurface inflow 6,720 6,720 6,720 Import 18.150 18,150 20,300 Subtotal 63,590 64,570 66,220 Increase in storage 230 Water leaving basin on surface Consumptive use 43,790 44,170 43,720 Surface outflow 2,230 2,080 1,740 Export 3,610 3,610 3,800 Subtotal 49,630 49,860 49,490 Subsurface Outflow — to Bunker Hill Basin 13,960 14,710 16,730 BUNKER HILL BASIN (22) Bunker Hill Basin is located in the east central portion of Upper Santa Ana Valley, and covers about 92 square miles. It is bounded on the west and southwest by Lytle and Colton Basins, on the northwest by Lower Cajon Basin, on the north and northeast by Devil Canyon Basin and San Bernardino Mountains, and on the south by San Timoteo and Yucaipa Basins and granitic hills northwest of the latter. Topography is the result of deposition and erosion b}^ Cajon Creek entering the valley from the northwest, by Santa Ana River and Mill Creek from the east, and by many smaller streams entering from mountains to the north and hills to the south. Each of the larger streams has formed a well-defined alluvial cone. For several miles out in the valley Mill Creek and Santa Ana River have cut many channels of considerable depth. General slope here ranges from 175 to 400 feet per mile. Along mountains which form the northeast boundary of the basin the slope is also steep, averaging about 250 feet per mile. On the Cajon Creek cone the slope is to the south- east, and averages 125 feet per mile. Where all cones coalesce in the cen- tral portion of the basin, topography is regular, with an average slope of 50 feet per mile. In the lower portion of the basin topography is again irregular. Elevations range from 960 feet where Warm Creek flows out of the basin, to 1,860 feet where Cajon Creek enters, and to about 2,500 feet at the easterly extremity where Mill Creek enters the valley. Soils 212 DIVISION OF WATER RESOURCES coverino' this basin are mosth^ lighter members of the Hanford and Tujunga series. In the vicinity of San Bernardino there are considerable areas of the less pervious Chino soils. Municipal development occupies about 19 percent of the area, about 36 percent is devoted to agriculture, and the remainder is in a more or less natural state. The local water supply, utilized both through diversion from surface streams and pumping from ground water, originates in precipitation on valley lands, inflow from 272 square miles of mountains and 2,100 acres of hills directl}^ tributary to the basin, and inflow on the surface from Yucaipa, Lj^tle, Lower Cajon, Devil Canyon and San Timoteo Basins, together with some underflow from the four last named. Imported water provides some addition to the supply. A considerable part of surface inflow and precipitation flows out into Colton Basin, together with some underflow, and water is exported in large amount to Colton and San Timoteo Basins. Like Main San Gabriel Basin, Bunker Hill Basin is one in which outflow of rising water responds quickly to changes in elevation of the water table, and it is therefore considered that neither excess nor over- draft exists, but that the basin serves as a regulator of outflow to basins downstream. Evaluation of items required * to estimate long-time mean outflow follows. Inflotv Estimated surface inflow to the basin averages 138,370 acre-feet, 114,670 acre-feet and 113,510 acre-feet annually in the 32-, 21- and 11-year periods, respectively, as derived in Table 166. Annual inflow from directly tributary mountain area, above gaging stations at which flow was measured during part of the period, is tabu- lated below. Thirt3^-two- and 21-year values for Mill and City Creeks, and 32-year value for Plunge Creek are derived by comparison with Santa Ana River. Mean annual inflow'^ in acre-feet 32-year 21-year 11-year Stream Station period period period Mill Creek 18261 32,320 26,020 26,960 Citv Creek 18915A 10.130 8,080 7,120 Plunge Creek 18957 6,900 5,540 5,750 Santa Ana River 19008 75,100*^ 60,340'' 55,720 = Subtotal 124,450 99,980 95,550 Estimated evaporation loss from Bear Valley Reservoir 2,.S50 2,080 Net inflow 122,100 97,900 95,550 ■ Including diversions above gaging stations. •' Full natural runoff, as reconstructed, corrected for effect of reservoir. <= Actual measured runoff, uncorrected for reservoir operation. The estimate of 32-year mean annual inflow from 12,160 acres of mountains directly tributary to the basin, and downstream from gaging stations at which above inflow was measured is based on the assumption that, if water is available, average consumptive use on the mountain area ranges from 18 to 19 inches, infl.ow values however being never less than 10 percent of the precipitation. The 11-year value is estimated to be 0.79 * Values of change in storage and precipitation, also required, are presented in Tables 5 and 7. SOUTH COASTAL BASIN INVESTIGATION 213 times the 32-year mean, this being the ratio between 11- and 32-year mean discharge of Santa Ana River. The corresponding ratio for the 21-year period is 0.80. Inflow from 2,100 acres of directly tributary hills is estimated to be 10 percent of the precipitation.* Inflow on the surface from other basins includes all surface outflow from Devil Canyon, San Timoteo and Lytle Basins, and a part of that from Lower Cajon and Yucaipa Basins. Subsurface inflow includes underflow out of Lower Cajon, Devil Canj^on, San Timoteo and Lytle Basins, and is estimated to average 35,200 acre-feet, 31,790 acre-feet and 34,420 acre-feet annually during the 32-, 21- and 11-year periods, respectively. TABLE 166. INFLOW TO BUNKER HILL BASIN Average annual for 32-year period, 1904-05 to 1935-36, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38, inclusive (Acre-feet) 32-year 21-year 11-year period period period Surface inflow From directly tributary mountains Measured during part of period — 122,100 Estimated =^ 2,790 From directly tributary hills Estimated ^ 340 From other basins Lower Cajon 2,970 Devil Canyon 5,200 San Timoteo 2,230 Yucaipa — 530 Lytle 2,210 Total surface inflow '^ 138,370 Subsurface inflow from other basins Lower Cajon 13,590 Devil Canyon 7,060 San Timoteo 13,960 Lytle 590 Total subsurface inflow 35,200 97,900 95,550 2,230 2,200 340 330 3,530 3,590 4,100 4,250 2,080 1,740 430 420 4,060 5,430 114,670 113,510 11,330 13,150 5,160 3,950 14,710 16,730 590 590 31,790 34,420 Includes a relatively small amount of underflow. Import In Table 167 estimated values of imports of water from Lytle, Devil Canyon and Lower Cajon Basin for each year since 1927-28 are presented. There is no import of sewage. During the 11-year period an annual average of 3,580 acre-feet was imported. Assuming that the import from Lower Cajon Basin in 1943-44 and the four -year average import from Lytle and Devil Canyon Basins during 1941-42 to 1944-45, inclusive, represent present average annual import, its estimated value is 8,490 acre-feet. * If Inflow from hills is assumed to follow the same regimen as flow in Santa Ana River, average inflow from that source is 270 acre-feet for both 21- and 11-year periods. 214 DIVISION OF WATER RESOURCES TABLE 167. IMPORT TO BUNKER HILL BASIN Year Acre-feet Year Acre-feet Year Acre-feet 1927-28 3,820 1928-29 3,460 1929-30 3,780 1930-31 3.260 1931-32 3,470 1932-33 3,720 1933-34 3,160 1934-35 2,990 1935-36 3,270 1936-37 4,130 1937-38 4,280 1938-39 5,080 1939-40 4,650 1940-41 6,100 1941-42 6,650 1942-43 8,200 1943-44 8,980 1944-45 9,180 Consumptive Use In Table 168 estimates of consumptive use based on culture surveys conducted by the Division of AYater Resources in 1932 and 1942 are presented. Unit consumptive use is discussed in Chapter Y. The greater part of the Cities of San Bernardino and Redlands overlie the basin. The principal agricultural crop, citrus, covers a large part of the area south of Santa Ana River, and that bordering the mountains on the north. Smaller acreages of other crops occupy level lands near San Bernardino. Moderately heavy brush, weeds and grass cover most of the unirri- gated area. TABLE 168. ESTIMATED AVERAGE ANNUAL CONSUMPTIVE USE IN BUNKER HILL BASIN Type of culture Unit con- sumptive use, feet 19S2 19Jf2 Acres Acre-feet Acres Acre-feet 3,811 43,456 1,256 3,042 4,504 17,105 36,040 2.692 16,230 261 929 1,391* 10,943 26,390 3,769 43,821 600 2,787 5,564 19,697 34'307 34,439 Valley and folded area Garden and field 1.4 2,722 Avocado and citrus 2.7 16,095 Deciduous 2.3 546 Alfalfa 3.0 1,014 Irrigated grass ^ 4.0 1,126* Domestic and industrial ^_ 1.8 9,503 Unirrigated 27,830 32-year period 1.3 21-year period 1.305 11-year period 1.295 Subtotal 32-year period 21-year period 11-year period Hill and mountain area Avocado and citrus 1.2 '' Grand total " 32-year period 21-year period 11-year period . 58,836 130 109,214 156 58,836 110,545 110,677 110,677 130 156 58,966 "II 109~,370 58,966 110,701 110,833 * Includes water-loving natural vegetation in pressure zone above Bunker Hill Dike. *> Difference between irrigated culture and natural vegetation. SOUTH COASTAL BASIN INVESTIGATION 215 Export In Table 169 estimated exports of water to Colton and San Timoteo Basins and of sewage to Colton Basin for each year since 1927-28 are presented. Exports include both pumped water and gravity water diverted within the basin. During the 11-year period an annual average of 67,500 acre-feet of water and 3,040 acre-feet of sewage was exported, a total of 70,540 acre-feet. Estimated average annual export of water under present conditions is 66,390 acre-feet, and of sewage 6,780 acre-feet, a total of 73,170 acre- feet. Present average annual export of gravity water to San Timoteo Basin is assumed to equal the historic average during the 21-year period. Average export of other water during 1941-42 to 1944-45, inclusive, and of sewage in 1944-45 alone, are assumed to represent the average from those sources under present conditions. TABLE 169. EXPORT FROM BUNKER HILL BASIN (Acre-feet) Year Water Sewage Year Water Sewage 1927-28 62,540 1936-37 62,510 3,550 1928-29 65,800 2,470 19.37-38 68,680 3,230 1929-30 63,.320 3,490 1938-.39 71,090 3,750 1930-31 70,210 3.290 1939-40 71,970 3,480 1931-32 67,570 3,200 1940-41 63,540 3,840 1932-33 71,880 2.980 1941-42 68,660 4,140 1933-34 73,610 3,920 1942-43 66,250 4,720 1934-.35 60,440 4,110 1943-44 64,490 5,590 1935-36 75,900 3.150 1944-45 66,600 6,780 Surface Otitfloiv During 11 -Year Period During the 11-year period more than half the surface outflow, that in Warm Creek, was measured at Station 17993A. Flow in Santa Ana River was measured at Station 17993B in 1927-28, at Station 18041 from 1928-29 to 1936-37, inclusive, and at Station 18003 from March 1939 to date. Station 18041 is above the junction with San Timoteo Creek, so small outflow originating in that source, estimated by entering the percolation diagram with measured discharges at Stations 18096 and 18128, is added. Outflow in Santa Ana River in 1937-38 is estimated by comparison with flow in the river at Prado, Station 15822. Outflow in the West Branch of Lytle Creek has been measured at Station 17982 since January, 1929. Runoff for 1927-28 and the first three months of 1928-29 was negligible. Relatively small outflow to Lytle Basin in Cajon Creek is estimated throughout by use of the percolation diagram and measured daily discharges at Stations 19433A and 19433B, modified to include estimated inflow below the stations. Estimated outflow during the 11-year period averages 38,190 acre-feet, of which 35,550 acre-feet goes to Colton Basin and 2,640 acre-feet to Lvtle Basin, as derived in Table 170. 216 DIVISION OF WATER RESOURCES TABLE 170. AVEPvAGE ANNUAL SURFACE OUTFLOW^ FROM BUNKER HILL BASIN DURING THE 11-YEAR PERIOD, 1927-28 TO 1937-38, INCLUSIVE Acre- feet To Colton Basin Measured, in Warm Creek 22,150" Partially estimated In Santa Ana River 12,850 In West Branch of Lytle Creek 550 Subtotal 35,550 To Lytle Basin Estimated, in Cajon Creek 2,640 Total 38,190 ■ Does not include outflow in canals which divert gravity water within the basin for export. •> Does not include effluent from City of San Bernardino sewage treatment plant. Subsurface Outflow Assuming that all items involved have been correctly evaluated, subsurface outflow during the 11-year period must, in accordance with principles set forth in Chapter V, have averaged 20,110 acre-feet annu- ally, as derived in Table 171. TABLE 171. ESTIMATED AVERAGE ANNUAL SUBSURFACE OUTFLOW FROM BUNKER HILL BASIN DURING THE 11-YEAR PERIOD, 1927-28 TO 1937-3 8, INCLUSIVE Acre- feet Water entering basin Precipitation 86,180 Surface inflow 113.510 Import 3,580 Subsurface inflow 34,420 Water coming from storage in basin 520 Subtotal 238,210 Water leaving basin on surface Surface outflow 38,190 Exported water 67,500 Exported sewage 3,040 Consumptive use 109,370 Subtotal 218,100 Subsurface Outflow — to Colton-Reche Canyon Area 20,110 Long-time Mean Surface Outflow The hydrologic equation used in the preceding article applies equally well in any period. Since neither excess nor overdraft is considered to exist, net change in storage over a cycle of long-time mean supply is zero. Assuming that subsurface outflow is the same in all periods, all items involved, other than surface outflow, have been evaluated for both 32- and and 21-year cycles. Assuming further that the 21-year period represents SOUTH COASTAL BASIN INVESTIGATION 217 the cycle of long-time mean supply, estimated mean annual surface out- flow is 38,440 acre-feet, as derived in Table 172. If the 32-year period were assumed to be the cycle, the derived value would be 64,930 acre-feet. Outflow in Cajon Creek to Lytic Basin for each year since 1920-21 is estimated by means of percolation curves which result in complete perco- lation up to 85 second-feet in Lower Cajon Basin and 100 second-feet in Bunker Hill Basin, and daily discharges in Lone Pine and Cajon Creeks at Stations 19433A and 19433B, respectively. Runoff in Lone Pine Creek was measured from 1920-21 to 1937-38, inclusive, and that in Cajon Creek from 1920-21 to date. Daily discharges in Lone Pine Creek after 1937-38 are estimated by comparison with Cajon Creek. Estimated daily discharges in Cajon Creek at Lower Cajon Basin boundary are increased by 45 percent to allow for inflow below the gaging stations. Annual com- bined runoff at the two stations for years prior to 1920-21 is estimated by comparison with San Antonio Creek. Outflow to Lytle Basin in each of these earlier years is estimated from the relationship between outflow and discharge at the stations, established since 1920-21. On this basis, esti- mated average annual outflow to Lytle Basin for the 32-year period is 1,570 acre-feet, and for the 21-year period, 2,490 acre-feet. Outflow in Santa Ana River during the 11-year period has been previously discussed. It has been measured at Station 18003 since March 1939. Outflow for years prior to 1927-28 and for 1938-39 is estimated from relationship of outflow to 32-year mean runoff indices for Santa Ana River, as established by years of record. On this basis, estimated mean annual outflow in Santa Ana River for the 32-year period is about 21,000 acre-feet, and for the 21-year period, 14,000 acre-feet, nearly all of which is storm water. Deducting estimated outflow in Cajon Creek and Santa Ana River from calculated total mean outflow from the basin, leaves approximately 42,000 acre-feet mean annual outflow in Warm Creek for the 32-year period, and 22,000 acre-feet for the 21 -year period. Most of the outflow in Warm Creek is rising water. TABLE 172. ESTIMATED LONG-TIME MEAN ANNUAL SURFACE OUTFLOW FROM BUNKER HILL BASIN ASSUMING THE 21 -YEAR PERIOD, 1922-23 TO 1942-43, INCLUSIVE, TO BE A CYCLE OF LONG-TIME MEAN SUPPLY Acre- feet Supply to basin Precipitation 87,600 Surface inflow 114.670 Import - 8,490 Subsurface inflow 31,790 Subtotal -Timm 242,550 Demand on basin Consumptive use 110,830 Export 73,170 Subsurface outflow 20,110 Subtotal 204,110 Surface Outflow 38,440 To Lytle Basin 2,490 To Colton-Reche Canyon Area : In Santa Ana River 14,000 In Warm Creek 21,950 218 DIVISIOX OF WATER RESOURCES COLTON-RECKE CANYON AREA Colton Basin (21b) Reche Canyon Basin (45) There is no physical barrier to movement of ground water between Reche Canyon and Colton Basins. Since development in the former basin is limited to dry-farming it is obvious that it has no overdraft, and since no changes have occurred which would tend to decrease outflow, and thus increase supply, it has no excess. Because of this the two basins are treated as a unit, Reche Cam'on being considered an arm of Colton Basin and a source of supply to it. The area is located in the south central portion of Upper Santa Ana Valley, and covers about 19 square miles. Colton Basin is bounded on the southwest bv Riverside Basin, on the west and northwest bv Rialto Basin, and on the northeast and east by L3i:le and Bunker Hill Basins. Reche Canvon Basin extends southeasterlv from Colton Basin, and is bounded on the west and south by the granitic hills which border Riverside Basin and San Jacinto Valley, and on the north and east by San Timoteo Basin. Topography of Colton Basin is somewhat rolling and irregular because of sand dune formations which cover a considerable part of its lower portion. Average slope is less than 100 feet per mile, and elevations range from 925 feet along Santa Ana River to 1,425 feet at the most northerly point in the basin. The surface overlying Reche Canyon Basin is steep and irregular, ranging in elevation above sea level from 1,025 feet at Colton Basin boundarv, to 2.100 feet along the toe of hills to the southeast. The soils are mostly lighter members of the Hanford and Tujunga series, with however a considerable area of windblo^vn Oakley sand in Colton Basin, and some residual Sierra loam in Reche Canyon Basin. The local water supply, utilized in part through diversion from sur- face streams and in part through pumping from ground water, originates in precipitation on valley land, inflow from 3,630 acres of hills directly tributary to the area, and inflow both underground and on the surface from Bunker Hill Basin, the greater part of the last named as flood flow and rising water in Santa Ana River and Warm Creek. Imported water, most of which is carried through and exported, provides a relatively large addition to the supply entering the area. Considerable sewage is also imported. A large part of the surface inflow and precipitation flows out into Riverside Basin, together with underflow, and water is exported in large amount to Riverside, Rialto and Chino Basins. Local sewage is exported to Riverside Basin. A part of the sewage imported from Bunker Hill Basin flows through into Riverside Basin in Santa Ana River. This is considered a part of the flow in that stream rather than export. Long-time mean annual supply entering the area under present con- ditions is greater than present annual demand, but storage capacity above present water table is so limited that all unused water soon flows out, constituting a part of the supply to basins downstream. It is the long-time mean outflow to downstream basins under present development which is herein estimated. Evaluation of items required * for the esti- mate follows. * Values of change in storage and precipitation, also required, are presented in Tables 5 and 7. SOUTH COASTAL BASIN INVESTIGATION 219 Inflow Estimated annual surface inflow averages 63,610 acre-feet, 36,220 acre-feet and 35,810 acre-feet during the 32-, 21- and 11-year periods, respectively, as derived in Table 173. The estimate of inflow from 3,630 acres of hills directly tributary to the area is based on the assumption that 6 percent of precipitation on the hills runs off. The greater part of the surface outflow and most of the underflow from Bunker Hill Basin is a part of the inflow to the area. Subsurface inflow, with the exception of the relatively small amount referred to by note in Table 173, is all from this source, and during the 11-year period averaged 20,110 acre-feet annually. TABLE 173. SURFACE INFLOW TO COLTON-RECHE CANYON AREA Average annual for 32-year period, 1904-05 to 193 5-36, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38, inclusive (Acre-feet) 32-year 21-year 11-year period period period From directly tributary hills Estimated" 250 270 260 From other basins Bunker Hill 63,360 35,950 35,550 Total 63,610 36,220 35,810 a Includes a relatively small amount of underflow. Itnport In Table 174 estimated values of imports of water from both gravity and pumped sources in Rialto, Bunker Hill and Lytle Basins, and of sewage from Bunker Hill Basin, for each year since 1927-28 are pre- sented. During the 11-year period an annual average of 59,780 acre-feet of water, and 3,040 acre-feet of sewage was imported, a total of 62,820 acre-feet. Estimated average annual import of water under present conditions is 64,180 acre-feet, and of sewage 6,780 acre-feet, a total of 70,960 acre- feet. It is assumed that average annual historic import of water during the four-year period, 1941-42 to 1944-45, inclusive, and the historic import of sewage during 1944-45 represent the respective average annuals under present conditions. TABLE 174. IMPORT TO COLTON-RECHE CANYON AREA (Acre-feet) Year Water Seivage Year Water Sewage 1927-28 56,800 1928-29 63,930 2,470 1929-30 59,080 3,490 1930-31 64,460 3,290 1931-32 55,070 3,200 1932-33 60,920 2,980 1933-34 66,700 3,920 1934-35 52,520 4,110 1935-36 67,840 3,150 1936-37 53,600 3,550 1937-38 56,620 3,230 1938-39 61,780 3,750 1939-40 65,790 3,480 1940-41 53,580 3,840 1941-42 64,820 4,140 1942-43 64,380 4,720 1943-44 62,410 5,590 1944-45 65,100 6,780 220 DIVISION OF WATER RESOURCES Consumptive Use In Table 175 estimates of consumptive use based on culture surveys conducted by the Division of Water Resources in 1932 and 1942 are presented. Unit consumptive use is discussed in Chapter V. A portion of the City of Rialto, and the greater part of the City of Colton, overlie Colton Basin. Citrus covers most of its northerly portion, and relatively smaller areas of other crops occupy lower lands. A part of its unirrigated acreage is devoted to grapes, and the remainder is largely covered by grass and weeds. In Eeche Canyon Basin valley lands are largely grass covered or dry farmed, with moderateh' hea\^ brush on folded areas. TABLE 17 5. ESTIMATED AVERAGE ANNUAL CONSUMPTIVE USE IN COLTON-RECHE CANYON AREA Unit con- sumptive 1932 1942 Tijpe of culture use, feet Acres Acre-feet Acres Acre-feet Valley and folded area Garden and field Avocado and citrus Deciduous Alfalfa Irrigated grass Domestic and industrial 1 Unirrigated 32-year period 1.1 7,467 21-year period 1.111 7,541 11-year period 1.103 7,421 1.4 302 423 122 171 2.5 3,622 9,055 3,442 8,605 2.3 137 315 97 223 3.0 133 399 338 1,014 3.0 30 90 50 150 1.8 1,365 2,457 1,480 2,664 6,728 ^^ 6,788 Total 12,317 12,317 32-year period 20,294 21-year period 20,368 11-year period 20,160 • Export In Table 176 estimated exports of water and sewage for each year since 1927-28 are presented. AYater, both gravity and pumped, is exported to Chino, Rialto and Riverside Basins, while sewage goes to Riverside Basin. During the 11-year period annual averages of 66,620 acre-feet of water, and 470 acre-feet of sewage were exported, a total of 67,090 acre-feet. Estimated average annual export of water under present conditions is 73,020 acre-feet, and of sewage 890 acre-feet, a total of 73,910 acre-feet. Present average annual exports of water and of sewage are assumed to equal the historic average annual for the four-year period, 1941-42 to 1944-45, inclusive, and the 1944-45 value, respectively. SOUTH COASTAL BASIN INVESTIGATION 221 TABLE 176. EXPORT FROM COLTON-RECHE CANYON AREA (Acre-feet) Year Water ^ Sewage Year Water ' Sewage 1927-28 77,740 1928-29 80,930 1929-30__ 68,190 1930-31 70,370 1931-32 62,060 1932-33 64,930 1933-34 65.840 1934-35 53,840 1935-36 69.720 450 1936-37 56.200 470 1937-38 62,960 420 1938-39 67,530 440 1939-40 70,920 440 1940-41 56,440 4<)0 1941-42 72,830 420 1942-43 71,670 480 1943-44 71,140 500 1944-45 76,450 560 610 660 710 970 670 710 840 890 Includes part of imported sewage. Outflotu In accordance with the physical law that all water which enters Colton-Reche Canyon Area during any period, including its overlying area, must either go into storage, be consumed or exported, or flow out either on the surface or underground, estimated surface outflow averages 56,270 acre-feet, 29,130 acre-feet and 27,510 acre-feet annually in the 32-, 21- and 11-year periods, respectively, as derived in Table 177. Since the 21-year value is the more conservative, 29,130 acre-feet is considered to be the long-time mean annual surface outflow. Subsurface outflow is arbitrarily assumed to equal subsurface inflow, i.e. 20,110 acre-feet annually. TABLE 177. ESTIMATED OUTFLOW FROM COLTON-RECHE CANYON AREA Average annual for 32-year period, 1904-05 to 193 5-36, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38, inclusive (Acre-feet) 32- year period 21-year period J 1-year period Water entering area Precipitation 15.900 Surface inflow 63.610 Imported water 64.180 Imported sewage — 6,780 Subsurface inflow 20,110 Decrease in storage Subtotal — 170,580 Water leaving basin other than outflow Exported water 73,020 Exported sewage 890 Consumptive use 20,290 Subtotal 94,200 Outflow — to Riverside Basin 76,380 Subsurface 20,110 Surface 56,270 16,230 16,000 36,220 35.810 64,180 59,780 6,780 3,040 20,110 20,110 130 143,520 134,870 73,020 66,620 890 470 20,370 20,160 94,280 87,250 49,240 47,620 20,110 20,110 29,130 27,510 222 DIVISION OF WATER RESOURCES RIVERSIDE-ARLINGTON AREA Riverside Basin (27) Arlington Basin (28) The boundary between Riverside and Arlington Basins was estab- lished to coincide with the ground water divide which existed in 1932. Under other conditions this divide might shift and ground water might then flow across the established boundary from either basin to the other, depending upon direction of water table slope then existing. Both basins receive a large imported supply from Bunker Hill and Colton Basins. For these reasons the two basins are treated as a unit. The area is located in the south central portion of Upper Santa Ana Valley, and covers about 75 square miles. Granitic hills form the south- east and south boundary, as well as the greater part of that on the southwest, west and northwest. The alluvium, however, is continuous between Arlington and Temescal Basins over a wddth of a little more than one-half mile, and between Riverside and Chino Basins over a con- siderably greater distance. Colton Basin bounds Riverside Basin on the northeast. Topography of Riverside-Arlington Area is irregular, with slopes generally toward the river ranging from 10 to 400 feet per mile. In the southwesterly portion of Arlington Basin slope is toward Temescal Basin. Elevations above sea level range from 685 to 1,300 feet. Soils covering the portion of Riverside Basin which lies north of Santa Ana River are mostly lighter members of the Hanford series, with a fairly large area of Oakley sand west of the City of Colton. Adjoining either side of the river a strip ranging from one-half to two miles in width is covered with still more pervious Tujunga sands. South of the river lie extensive areas of Hanford, Ramona and Placentia soils, with the latter predominating. Except for a considerable area of heavy Ramona clay loam lying between the City of Arlington and the river, soils covering Arlington Basin are about equally divided between the Hanford and Placentia series. Placentia soils occur in higher, more steeply sloping areas. Municipal development occupies about 18 percent of the area, about 51 percent is devoted to agriculture, and the remainder is in a more or less natural state. The local water supply, utilized to a minor extent through diversion from surface streams, but more through pumping from ground water, originates in precipitation on valley land, inflow^ from 44,370 acres of hills directly tributary to the area, inflow both underground and on the surface from Colton Basin, and small surface inflow from Chino Basin. The greater part of surface inflow is flood flow and rising water in Santa Ana River. Imported water, together with some sewage, provides a large addition to the supplj^ A considerable part of surface inflow and precipitation flows out into Chino and Temescal Basins, together with rising water and underflow. The export of water to these two basins is also considerable. The water table over most of the area stands higher than the Santa Ana River bed at Riverside Narrows, and there is at all times a large flow of rising water at that point, the amount of which is dependent upon the amount of water used in the basin. So long as this condition exists there is considered to be neither excess nor overdraft, and it is the long- time mean surface outflow which is herein estimated. Evaluation of items required * to estimate its amount follows . * Values of change in storage and precipitation, also required, are presented in Tables 5 and 7. SOUTH COASTAL BASIN INVESTIGATION 223 Inflotu Estimated annual surface inflow averages 58,450 acre-feet, 31,420 acre-feet and 29,770 acre-feet in the 32-, 21- and 11-year periods, respec- tively, as derived in Table 178. Estimates of inflow from 44,370 acres of hills directly tributary to the area are based on the assumption that five per cent of precipitation on the hills runs off.* All surface outflow from Colton-Reche Canyon Area, and a small part of that from Chino Basin enters Riverside- Arlington Area. Subsurface inflow, from Colton-Reche Canyon Area, is estimated to average 20,110 acre-feet annually. TABLE 178. SURFACE INFLOW TO RIVERSIDE- ARLINGTON AREA Average annual for 32-year period, 1904-05 to 1935-36, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38, inclusive (Acre-feet) 32-year *21-ijear ll-ycar period period period From directly tributary hills Estimated =* 1,940 2,040 2,020 From other basins Colton-Reche Canyon Area. Chino Total 50,270 29,1.30 27,510 240 250 240 58,450 31,420 29,770 a Includes a relatively small amount of underflow. Import In Table 179 estimated values of imports of water and sewage for each year since 1927-28 are presented. Water is imported from Chino and Colton Basins, while sewage inflow is from Coltoii Basin. Imported water all originates in Colton Basin, and is from both gravity and pumped sources there. During the 11-year period, an annual average of 64,860 acre-feet of water, and 470 acre-feet of sewage were imported, a total of 65,330 acre-feet. Estimated average annual import of water under present conditions is 70,610 acre-feet, and of scAvage 890 acre-feet, a total of 71,500 acre- feet. It is assumed that the historic import for the four-j^ear period, 1941-42 to 1944-45, inclusive, and that for the year 1944-45 alone, deter- mine the present average annual values for water and sewage respec- tively. TABLE 179. IMPORT TO RIVERSIDE-ARLINGTON AREA (Acre-feet) Year Water Seicage Year Water Sewage 1927-28. 1928-29- 1929-30. 1930-31. 1931-32. 1932-33. 1933-34. 1934-35. 1935-36. 70,460 79,530 66,590 68,790 60,310 62,480 64,020 52,560 67,670 450 1936-37 .54,210 470 1937-38— 60,850 420 1938-39 65,700 440 1939-40 68,890 440 1940-41 54,700 400 1941-42 70,890 420 1942-43 69,160 480 1943-44 68,600 500 1944-45 73,790 560 610 660 710 970 670 710 840 890 * If inflow from hills is assumed to follow the same regimen as flow in Santa Ana River, estimated average annual inflow from that source during the 21-year period is 1,550 acre-feet, and during the 11-year period, 1,530 acre-feet. 224 DIVISION OF WATER RESOURCES Consumptive Use In Table 180 estimates of consumptive use based on culture surveys conducted by the Division of Water Resources in 1932 and 1942 are presented. Unit consumptive use is discussed in Chapter V. The Cities of Riverside and Arlington lie within the area. The greater part of the extensive citrus acreage is on northwesterly sloping higher ground, south of the trough of the valley. Other crops dominate lower lands. Natural vegetation, which covers nearly one-third of the area, is largely grass and weeds. Water-loving vegetation, covering areas where the water table is at or near the surface, is classified as irrigated grass. The rate of consumption assigned to this vegetation and to alfalfa grown under simi- lar conditions is higher than that used elsewhere. TABLE 180. ESTIMATED AVERAGE ANNUAL CONSUMPTIVE USE IN RIVERSIDE-ARLINGTON AREA Type of culture Unit con- sumptive 1932 19Jf2 use, feet Acres Acre-feet Acres Acre-feet Valley area Garden and field Avocado and citrus Deciduous Alfalfa Irrigated grass ^ Domestic and industrial- Unirrigated 32-year period . 21-year period 11-year period Subtotal 32-year period — 21-year period 11-year period Hill area Garden and field Avocado and citrus Deciduous Alfalfa Domestic and industrial- Subtotal Grand total 32-year period 21-year period 11-year period — 1.4 3,602 5.043 4.070 5,698 2.6 14,339 37.281 14,164 36,826 2.3 2,665 6,130 2,130 4,899 3.8 2,131 8,098 2,258 8,580 3.8 1,660 6,308 2,195 8,341 1.8 8,261 14,870 8,516 15,329 — — .— 15,519 14,844 «,_ 0.9 13,360 0.922 13,686 0.918 14,246 48,177 48,177 ^_ 93,033 — .— — - 93,359 — 91,976 0.5'' 194 97 209 104 1.7" 1.903 3,235 1,923 3,269 1.5" 184 276 179 268 2.9" 80 232 80 232 1.0" 1,143 1,143 4,983 1,283 3,674 1,283 — 3,504 5,156 51,681 51,851 98,189 98,515 96.959 a Includes natural water-loring vegetation. ^ Difference between irrigated culture and natural vegetation. Export In Table 181 estimated exports to Chino and Temescal Basins of combined gravity and pumped water for each year since 1927-28 are presented. There is no sewage outflow. During the 11-year period an annual average of 12,760 acre-feet was exported. Estimated average SOUTH COASTAL BASIN INVESTIGATIOiST 225 annual export under present conditions is 10;790 acre-feet, the historic average for the four-year period, 1941-42 to 1944-45, inclusive. TABLE 181. EXPORT FROM RIVERSIDE-ARLINGTON AREA Year Acre-feet Year Acre-feet Year Acre-feet 1927-28 13,260 1933-34 15,400 1939-40 11,210 1928-29 15,180 1934-35 12,080 1940-41 7,910" 1929-30 13,530 1935-36 15,480 1941-42 9,230 1930-31 13,910 1936-37 9,050 1942-43 10,830 1931-32 11,360 1937-38 8,520 1943-44 11,060 1932-33 12,610 1938-39 8,170 1944-45 12,030 " Includes a small export to San Jacinto Valley. Surface Outflow During 11 -Year Period Estimated surface outflow during the 11-year period averages 50,100 acre-feet annually, 47,970 acre-feet of it to Chino Basin and 2,130 acre- feet to Temescal Basin, as derived in Table 182. Discharge of Santa Ana River at Riverside Narrows was measured at Station 16933 in 1927-28, and at Station 16953 after January 8, 1929, except for about four and one-half months in 1937-38. Runoff during periods of no record in 1928-29 and 1937-38 is estimated by comparison v/ith discharge of the river at Station 15822, near Prado. The estimate of rising water outflow in Arlington Drain is based on intermittent measurements since 1941-42 at Station 15991. Estimated unmeasured outflow from the area includes 75 percent of inflow from 8,510 acres and 50 percent of that from 17,100 acres of directly tributary hills, and 5 percent of precipitation on 16,880 acres of valley land. TABLE 182. AVERAGE ANNUAL SURFACE OUTFLOW FROM RIVERSIDE- ARLINGTON AREA DURING THE 11-YEAR PERIOD, 1927-28 TO 1937-38, INCLUSIVE Acre-feet Measured during part of period Santa Ana River at Riverside Narrows.' 47,170 Estimated, originating in Rising water in Arlington Drain 1,500 Directly tributary hills 640 Precipitation on valley land 790 Surface Outflow 50,100 To Chino Basin, at Riverside Narrows 47,170 To Chino Basin, near Arlington 800 Total to Chino Basin 47,970 To Temescal Basin 2,130 Subsurface Outflotv During the 1 1 -Year 'Period Assuming that all items involved have been correctly evaluated, subsurface outflow during the 11-year period must, in accordance with principles set forth in Chapter V, have averaged 8,550 acre-feet annually, as derived in Table 183. Based on cross sections of the alluvium at River- is— 7106I 226 DIVISION OF WATER RESOURCES side Narrows and at Temescal Basin boundary, underflow at the two points is estimated independently. The remainder enters Chino Basin above Riverside Narrows. TABLE 183. ESTIMATED AVERAGE ANNUAL SUBSURFACE OUTFLOW FROM RIVERSIDE-ARLINGTON AREA DURING THE 11-YEAR PERIOD, 1927-28 TO 193 7-3 8, INCLUSIVE Acre-feet Water entering area Precipitation 49,400 Surface inflow 29,770 Import 65,330 Subsurface inflow 20,110 Decrease in storage 3,760 Subtotal 168,370 Water leaving basin on surface Surface outflow, to Chino Basin 47,970 Surface outflow, to Temescal Basin 2,130 Export 12,760 Consumptive use 96,960 Subtotal 159,820 Subsurface Outflow 8,550 To Temescal Basin 3,000 To Chino Basin, at Riverside Narrows 500 Subtotal 3,500 To Chino Basin, above Riverside Narrows 5,050 Long-time Mean Oiitflotv The hydrologic equation expressed in the foregoing article applies equally well in any period. Since it is considered that neither excess nor overdraft exists, net change in storage over a cycle of long-time mean supply is zero. Assuming that subsurface inflow from Colton Basin is the same in all periods, all items involved, other than outflow, have been evaluated for both 32- and 21-year cycles. If the 21-year period is assumed to represent the cycle of long-time mean supply, estimated long-time mean annual outflow is 63,580 acre-feet, as derived in Table 184. Assum- ing that the percentage of precipitation on valley land, and of inflow from tributary hills which flows out, is the same as for the 11-year period, and that subsurface outflow to Chino and Temescal Basins is the same in all periods, but that lowering of the water table in the lower portion of Arlington Basin results in annual surface outflow to Temescal Basin of only 2,000 acre-feet, resulting surface outflow at Riverside Narrow^s averages 52,220 acre-feet annuall}^ If the 32-year mean values are sub- stituted, the derived average annual outflow from the area is 88,550 acre-feet, of which 77,230 acre-feet is on the surface at Riverside Narrows. SOUTH COASTAL BASIN INVESTIGATION 227 TABLE 184. ESTIMATED AVERAGE ANNUAL OUTFLOW FROM RIVERSIDE- ARLINGTON AREA ASSUMING THE 21-YEAR PERIOD, 1922-23 TO 1942-43, INCLUSIVE, TO BE ONE OF LONG-TIME MEAN SUPPLY Acre-feet Water entering area Precipitation 49,860 Surface inflow 31,420 Import 71,500 Subsurface inflow 20,110 Subtotal 172,890 Water leaving area other than outflow Export 10,790 Consumptive use 98,520 Subtotal 109,310 Outflow 63,580 Surface, to Temescal Basin 2,000 Surface, to Chino Basin near Arlington 810 Subsurface, to Temescal Basin 3,000 Subsurface, to Chino Basin : At Riverside Narrows 500 Above Riverside Narrows 5,050 Subtotal 11,360 Surface, to Chino Basin at Riverside Narrows 52,220 TEMESCAL BASIN (29) Temescal Basin is located in the southerly portion of Upper Santa Ana Valley, and covers about 29 square miles. It is bounded on the south- west and west by Santa Ana Mountains and Santa Ana Narrows Basin, on the north and northwest by Chino Basin and granitic hills, on the northeast by Arlington Basin and granitic hills, and on the east and southeast by granitic hills and Temescal Canyon. Santa Ana River fol- lows the boundary between Temescal and Chino Basins and is assumed to lie just within the latter. Topography is somewhat irregular, though not quite so variable as in other basins lying south of Santa Ana River in Upper Santa Ana Valley. Slope is generally to the north and averages about 200 feet per mile. Elevations range from 475 feet to about 1,500 feet above sea level. Soils are mostly lighter members of the Yolo series, with however a considerable area of Yolo clay loam and Ramona loam, and smaller deposits of heavier Ramona and Chino clay loams. Hanford soils occupy narrow bottom lands along Santa Ana River and Temescal Creek, and Placentia soils cover rougher lands between the two streams. Municipal development occupies about 10 percent of the area, 42 percent is devoted to agriculture, and the remainder is in a more or less natural state. The local water supply, utilized to a minor extent through diversion from surface streams, but more through pumping from ground water, originates in precipitation on valley land, inflow from 9,680 acres of mountains and 11,800 acres of hills directly tributary to the basin, and inflow both underground and on the surface from Arlington Basin and Temescal Canyon, the greater part of the last named as flood flow in Temescal Creek. Imported water provides a large addition to the supply. 228 DFV^ISION OF WATER RESOURCES A considerable part of the surface inflow and precipitation flows out into Chino Basin, together with large underflow. There is no export of water or sewage at present, although water was exported to Chino Basin from 1929-30 to 1934-35, inclusive. The greater part of the water herein considered subsurface outflow rises to the surface in the lower portion of the basin and actually crosses the basin boundary on the surface. Slope of the water table toward the river is regular, indicating that there is no physical barrier to movement of ground water toward the river from the area north of the City of Corona where a large part of the extractions occurs. This being true, raising the water table there must result in increase of rising water in the river, or of subsurface outflow from the basin. Raising the water table sufficiently to bring about balance between long-time mean supply, demand and outflow is not considered to constitute excess, and it is the long-time mean subsurface outflow which is herein estimated. Evaluation of items required * for this estimate follows. Inflow Estimated annual surface inflow to the basin averages 12,260 acre- feet, 8,690 acre-feet and 7,400 acre-feet in the 32-, 21- and 11-year periods, respectively, as derived in Table 185. Values of inflow from Temescal Canyon for years prior to January, 1928, when measurement at Station 15985 started, are estimated by comparison with Santa Ana River. The estimate of 32-year mean annual inflow from 9,680 acres of mountains directly tributary to the basin, and downstream from Station 15985 ,is based on the assumption that, if water is available, average consumptive use is 19 inches, the inflow however being never less than 10 percent of the precipitation. Average annual inflow from mountains during the 11-year base period is estimated to be 0.79 times the 32-year mean, this being the ratio between 11- and 32-year mean discharge of Santa Ana River. The corresponding ratio for the 21-year period is 0.80. Inflow from 11,800 acres of directly tributary hills is estimated to be 10 percent of the precipitation.! Subsurface inflow from Arlington Basin is estimated to average 3,000 acre-feet annually. TABLE 18 5. SURFACE INFLOW TO TEMESCAL BASIN Average annual for 32-year period, 1904-0 5 to 193 5-36, inclusive; 21 -year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-3 8, inclusive (Acre-feet) 32-year 21-year 11-year period period period Measured during part of period From Temescal Canyon, Station- 15985 7,400 4,250 2,870 Estimated * From directly tributary mountains — 2,270 1,820 1,790 From directly tributary hills 590 620 610 From other basins Arlington 2,000 2,000 2,130 Total 12^60 8^6 7,400 » Includes a relatively small amount of underflow. ' ' . " * Values of change in storage and precipitation are presented in Tables 5 and 7. t If runoff from hills is assumed to follow the same regimen as flow in Santa Ana River, average annual inflow from that source is 470 acre-feet for both the 21-year and 11 -year periods. SOUTH COASTAL BASIN INVESTIGATION 229 Import In Table 186 estimated values of imports of water for each year since 1927-28 are presented. There is no import of sewage. Water is imported from Riverside-Arlinj]:ton Area, Temescal Canyon and San Jacinto Valley, and is from both gravity and pumped sources. During the 11-year period, it averaged 14,550 acre-feet annually. Average annual import under present conditions is estimated to equal the historic mean for the four-A^ear period, 1941-42 to 1944-45, inclusive, or 15,420 acre-feet. TABLE 186. IMPORT TO TEMESCAL BASIN Year Acre-feet Year Acre-feet Year Acre-feet 1927-28 15,010 1928-29 -J. 15,960 1929-30 16,070 1930-31_r 14,540 1931-32 12,740 1932-33 13,440 1933-34 14,800 1934-35 12,590 1935-36 17,080 1936-37 13,490 1937-38 14,280 1938-39 14,920 1939-40 14,580 1940-41 11,190 1941-42 15,990 1942-43 14,880 1943-44 15,450 1944-45 15,340 Consumptive Use In Table 187 estimates of consumptive use based on culture surveys conducted by the Division of Water Resources in 1932 and 1942 are pre- sented. Unit consumptive use is discussed in Chapter V. The City of Corona is centrally located in the area. Citrus covers the high lands south of the city, while other crops are scattered over lower lands between the city and river. Natural vegetation on unirrigated lands is mostly weeds and light brush. 230 DmSION OF WATER RESOURCES TABLE 187. ESTIMATED AVERAGE ANNUAL CONSUMPTIVE USE IN TEMESCAL BASIN Type of culture Valley area Garden and field Avocado and citrus Deciduous Alfalfa Irrigated grass Domestic and industrial-. Unirrigated 32-year period 21-year period 11-year period Subtotal 32-year period 21-year period 11-year period Hill and mountain area Garden and field Avocado and citrus Deciduous Alfalfa Irrigated grass Domestic and industrial. Subtotal ~ Grand total 32-year period 21-year period 11-year period Unit con- sumptive 1932 1942 use, feet Acres Acre- feet ■ Acres Acre- feet 1.4 957 1,340 892 1,249 2.5 5,278 13,195 5,598 13,995 2.3 383 881 93 214 3.0 584 1,752 394 1,182 3.0 79 237 659 1,977 1.8 1,413 2,543 1,833 3,299 » — 9,617 ____ 8,842 1.1 — ~ — — M. — ^ •■•■^•a 9,726 1.128 9,974 1.122 10,790 18,311 18,311 — -, 31,642 _ — ..^ 31,890 30,738 0.5" 571 286 571 286 1.6 » 99 158 184 294 1.4 » 419 587 399 559 2.1" 64 134 74 155 2.1 > 202 424 202 424 0.9* 484 436 494 445 1,839 2,025 1,924 2,163 20,150 20,235 32,763 33,805 34,053 ■ Difference between Irrigated culture and natural vegetation. Export In Table 188 estimated values of export to Chino Basin of pumped water for each year of the period, 1929-30 to 1934-35, inclusive, are presented. There was no export prior to the former year and it was stopped in the latter through court action. During the 11-year period an annual average of 1,270 acre-feet of water was exported. TABLE 188. EXPORT FROM TEMECAL BASIN Tear Acre-feet Year Acre-feet 1929-30 910 1930-31 3,680 1931-32 3,320 1932-33 2,740 1933-34 3,100 1934-35 210 - SOUTH COASTAL BASIN INVESTIGATION 231 Surface Otitjloiv Outflow on the surface includes part of the inflow from directly tributary mountains and hills, part of that from Arlington Basin and Temescal Canyon, and runoff originating in precipitation on the over- lying valley. It is estimated to average 4,600 acre-feet, 3,220 acre-feet and 3,440 acre-feet in the 32-, 21- and 11-year periods, respectivly, as derived in Table 189. Mean daily discharge of Temescal Creek at Station 15985, near the upper boundary of the basin, has been measured since January, 1928. Using these daily discharges and a percolation curve which results in complete percolation up to 67 second-feet, outflow of water from above the station is estimated for each year since 1927-28. Using the relationship between annual outflow and annual discharge at the station, so estab- lished, and discharge at the station in earlier years derived by com- parison with Santa Ana River, outflow originating above the gaging station during years prior to 1927-28, is estimated. The greater part of inflow from directly tributary mountains flows northward across the alluvium an average distance of about four miles into Temescal Wash, and thence an additional distance of two to three miles into Santa Ana River. A smaller area of mountains draining directly to the river lies much closer to the basin boundary. Directly tributary hills border Temescal Creek for a distance of more than five miles. The channel of Temescal Creek is unpaved, Avith little restriction as to width. Estimated surface outflow from sources other than Temescal Canyon includes 25 percent of inflow from 8,310 acres and 90 percent of that from 1,370 acres of directly tributary mountains, 50 percent of inflow from directly tributary hills, 10 percent of surface inflow from Arlington Basin, and 5 percent of precipitation on valley land. TABLE 189. SURFACE OUTFLOW FROM TEMESCAL BASIN Average annual for 32-year period, 1904-05 to 1935-36, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-3 8, inclusive (Acre-feet) 32-year period 21-year period 3,040 11-year peirod 2,410 1,110 550 310 200 1,050 3,220 180 1,340 690 300 200 540 310 210 1,000 4,600 220 1,040 3,440 180 Estimated, originating in Temescal Creek * — Directly tributary mountains Directly tributary hills Inflow from other basins Precipitation on valley land Total To Santa Ana Narrows Basin To Chino Basin 4,380 * Storm outflow only, from above Station 15985. Subsurface Outflotu Assuming that all items involved have been correctly evaluated, subsurface outflow must, in accordance with principles set forth in Chapter V have averaged 8,770 acre-feet annually during the 11-year period, as derived in Table 190. Since neither overdraft nor excess is 3,260 232 DIVISION OF WATER RESOURCES considered to exist there is no change in storage over a long period of time, subsurface outflow in the 32- and 21-year periods, under present conditions, averages 13,000 and 11,600 acre-feet, respectively. Since the latter value is the more conservative it is considered to be the long-time mean annual subsurface outflow. The greater part of above so-called ' ' subsurface outflow ' ' consists of water rising to the surface in the lower portion of the basin, and actually leaving the basin as surface outflow in Temescal Creek or drainage ditches. However, it all originates in ground water within the basin, and for purposes of this study it is immaterial whether it be termed rising water or subsurface outflow. TABLE 190. ESTIMATED SUBSURFACE OUTFLOW FROM TEMESCAL BASIN* Average arxnual for 32-year period, 1904-05 to 1935-36, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-38, inclusive (Acre-feet) 32-1/ear 21-year 11-year period period period Water entering basin Precipitation 20,720 Surface inflow 12,260 Import 15,420 Subsurface inflow 3,000 Subtotal 51,400 Increase in storage Water leaving basin other than subsurface outflow Surface outflow 4,600 Consumptive use 33,800 Export 21,760 21,560 8,690 7.400 15,420 14.550 3,000 3,000 48,870 46,510 270 3,220 3,440 34,050 r,2.7r^o 1,270 SubtotMl 38,400 37,270 37,740 Subsurface Outflow » — to Chino Basin___ 13,000 11,600 8,770 » Includes rising water in lower portion of basin. CHINO BASIN (16) Cliino Basin occupies most of the westerly portion of Upper Santa Ana Valley, and covers about 237 square miles. It is bounded on the southAvest and west by Puente Hills and Spadra Basin, on the northwest by Pomona and Claremont Heig-hts Basins, on the north by Cucamonga Basin and San Gabriel Mountains, on the northeast and east by Rialto Basin, and on the southeast and south by Riverside and Temescal Basins and granitic hills. Topography of most of the surface is relatively smooth, with a slope generally southward toward Santa Ana River, ranging from 500 or more feet per mile near heads of well-defined alluvial cones of smaller streams which enter from mountains on the north, to 40 feet per mile below the Citv of Cliino. In its southerlv four or five miles the surface is irregular, finally dropping abruptly about 25 feet to bottom lanclr, along Santa Ana River and Chino Creek. Elevations range from 470 feet near Prado, to 2,750 feet at the northerly extremity of the basin. Soils are mosth^ lighter members of the Hanford and Tujunga series, SOUTH COASTAL BASIN INVESTIGATION 233 with heavier members of the Chino and Antioch series extending five or six miles northward from Santa Ana Kiver at Prado. The Hanford and Tnjmig-a soils are quite absorbent, the Chino less so, and the Antioch relatively impervious. Municipal development occupies about 6 percent of the area, 40 percent is devoted to irrigated agriculture, and about 20 percent to unirrioated grapes. The remainder is in a more or less natural state. The local water supply, utilized to a minor extent through diversion from surface streams, but more through pumping from ground water, originates in precipitation on valley land, inflow from 9,600 acres of mountains and 21,460 acres of hills directly tributary to the basin, and inflow both underground and on the surface from Claremont Heights, Pomona, Cucamonga, Rial to and Temescal Basins and Riverside-Arling- ton Area. Imported water provides a large addition to the supply. A considerable part of surface inflow and precipitation flows out into Santa Ana Narrow^s Basin, together with some underflow, while there is small surface outflow to Riverside Basin, and underflow to Spadra Basin. Water is exported in small am.ount to Cucamonga and Arlington Basins. Sewage outflow, to Puente Basin, is also small. Long-time mean annual net supply under present conditions is less than present annual demand, so an overdraft exists. Evaluation of items required * to estimate its amount follows. Infloru Estimated annual surface infloAV to the basin averages 100,790 acre- feet, 72,760 acre-feet and 68,490 acre-feet in the 32-, 21- and 11-year periods, respectively, as derived in Table 191. Inflow from directlj^ tributarv mountain area in Day Canyon, was measured at Station 18561 in 1927-28 and since 1929-30. Mean values for all periods are estimated by comparison with San Antonio Creek. The estimate of 32-year mean annual inflow^ from the remaining 6,450 acres of mountains directly tributary to the basin is based on the assumption that average annual consumptive use thereon is 18 inches. The 11-year value is estimated to be 0.79 times the 32-year mean, this being the ratio between 11- and 32-year mean annual discharges of Santa Ana River. The corresponding ratio for the 21-year period is 0.80. Inflow from the hills is estimated to be 10 percent of precipitation on them.t Inflow on the surface from other basins includes all surface outflow from Cucamonga Basin, and a part of that from Claremont Heights, Pomona, Rialto and Temescal Basins and Riverside- Arlington Area. Sub- surface inflow includes all underflow out of Pomona, Cucamonga, Rialto and Temescal Basins, and a part of that from Claremont Heights Basin and Riverside-Arlington Area, and averages 26,890 acre-feet, 25,490 acre-feet and 22,660 acre-feet during the 32-, 21- and 11-year periods, respectively. * Values of change in storage and precipitation are presented in Tables 5 and 7. t If inflow from hills is assumed to follow the same regimen of flow as in Santa Ana River, average annual inflow from that source is 2,060 and 2,030 acre-feet during the 21- and 11-3'ear periods, respectively. 234 DIVISION OF WATER RESOURCES TABLE 191. INFLOW TO CHINO BASIN Average annual for 32-year period, 1904-05 to 193 5-36, inclusive; 21-year period, 1922-23 to 1942-43, inclusive; and 11-year period, 1927-28 to 1937-3 8, inclusive (Acre-feet) 32-year 21-year 11-year period period period Surface inflow From directly tributary mountains Measured during part of period 4,260 4,030 3,690 Estimated "^ 5,880 4,710 4,650 From directly tributary hills Estimated^ 2,570 2,600 2,540 From other basins Claremont Heights 1,950 Pomona 390 Cucamonga 1.390 Rialto 1,970 Riverside-Arlington Area 78,000 Teraescal 4,380 Total Surface Inflow 100,790 Subsurface inflow, from other basins Claremont Heights 500 Pomona 520 Cucamonga 760 Rialto 6,560 Riverside-Arlington Area 5,550 Temescal " 13,000 Total Subsueface Inflow 26,890 25,490 22,660 2,000 2,980 390 380 1,080 1,200 1,880 1,820 53,030 47,970 3,040 3,260 72,760 68,490 500 500* 520 520 760 760 6,560 6,560 5,550 5,550 11,600 8,770 ■ Includes a relatively small amount of underflow. *» Includes rising water in lower portion of Temescal Basin. Import In Table 192 estimated imports of water for each year since 1927-28 are presented. There is no import of sewage. Water is imported from both gravity and pumped sources in Claremont Heights, Pomona, Cuca- monga, Rialto, and Lytle Basins, and in Colton-Reche Canj^on and Riverside-Arlington Areas. Prior to 1934-35 some was imported from Temescal Basin. During the 11-year period import from all sources averaged 39,150 acre-feet annually. Estimated average annual import under present conditions is 42,040 acre-feet. That from Claremont Heights, Pomona and Cucamonga Basins, and from Colton-Reche Canyon and Riverside-Arlington Areas, and pumped water from Rialto Basin is assumed to equal the average for the four-year period, 1941-42 to 1944-45, inclusive. The remainder of that from Rialto Basin has correlation with diversions from Lytle Creek, and is estimated to equal average annual import from that source for the period of record, 1927-28 to date, multiplied by the ratio between average annual diversion from Lytle Creek during the 21-year period, and during the period of dual record. Present average annual import from Lytle Basin is based upon the calculated amount which can be exported from that basin without exceeding safe yield. SOUTH COASTAL BASIN INVESTIGATION 235 TABLE 192. IMPORT TO CHINO BASIN Year Acre-feet Tear Acre-feet Year Acre-feet 1927-28 40,090 1933-34 37,660 1939-40 40.040 1928-29 39,020 1934-35 31,700 1940-41 36,520 1929-30 38,350 1935-36 41,370 1941-42 40,870 1930-31 38,320 1936-37 39,890 1942-43 48,980 1931-32__ 41,640 1937-38 43,070 1943-44 53,820 1932-33 38,600 1938-39 42,610 1944-45 49,960 Consumptive Use In Table 193 estimates of consumptive use based on culture surveys conducted by the Division of Water Resources in 1932 and 1942, and by the County of San Bernardino in 1940 are presented. Unit consumptive use is discussed in Chapter V. Portions of the cities of Pomona and Rialto, and all of Ontario, Upland, Chino, Cucamonga and Fontana, together with several smaller communities, overlie the basin. Irrigated crops are diversified, with citrus occupying higher ground, deciduous dominating the intermediate belt, and garden and field crops the lower lands. Of unirrigated land, roughly one-third is devoted to grapes, the remainder being covered in higher portions by moderately heavy brush, ranging to grass and weeds in lower areas. Along Santa Ana River and the lower reaches of Chino Creek there is a considerable area of water- loving vegetation. TABLE 193. ESTIMATED AVERAGE ANNUAL CONSUMPTIVE USE IN CHINO BASIN Unit con- sumptive 1932 1942 Type of culture use, feet Acres Acre-feet Acres Acre-feet Valley and folded area Garden and field 1.4 16.922" 23,691 16,922* 23,691 Avocado and citrus 2.6 22,252 57,855 22,667 58,934 Deciduous 2.3 13,264 30,507 14,394 33,106 Alfalfa 3.0 7,392 » 22,176 7,393* 22,179 Water-loving vegetation^ 4.0 4,726* 18,904 4,727* 18,908 Domestic and industrial 1.8 7,695 13,851 8,770 15,786 Unirrigated 79,487 76,865 32-year period 1.3 99,924 21-year period 1.305 100,309 11-year period 1.292 102,697 Subtotal 151,738 151,738 32-year period 272,528 21-year period 272,913 11-year period 269,681 Hill area Garden and field 0.3 <= 139 42 289 87 Avocado and citrus 1.4"= 134 188 134 188 Deciduous 1.2"= 202 242 202 242 Alfalfa 1.9"= 84 160 84 160 Domestic and industrial 0.7'= 216 151 216 151 Subtotal 775 783 925 828 Grand total 152,513 152,663 32-year period __— 273,356 21-year period — _ 273,741 11-year period 270,464 • Average of 1932 and 1942 surveys. •• Includes about 100 acres of irrigated grass. « Difference between iirigated culture and natural vegetation. 236 DIVISION OF WATER RESOURCES Export In Table 194 estimated exports of water and sewage for each year since 1927-28 are presented. Water from both gravity and pumped sources is exported to Riverside- Arlington Area and Cucamonga Basin, while sewage goes to Puente Basin. During the 11-year period an annual average of 1,380 acre-feet of water and 550 acre-feet of sewage was exported, a total of 1,930 acre-feet. Estimated average annual export of water under present conditions is 1,710 acre-feet, and of sewage 1,110 acre-feet, a total of 2,820 acre-feet. The values for water and for sewage are equal to the historic average for the four-year period, 1941-42 to 1944-45, inclusive, and the 1944-45 value, respectively. TABLE 194. EXPORT FROM CHINO BASIN (Acre-feet) Year Water Sewage Year Water Sewage 1927-28 1,600 1928-29 1,440 1929-30 1,420 1930-31 1,580 1931-32 1,440 1932-33 390 1933-34 1,040 1934-35 1,310 1935-36 1,340 430 1936-37 1,760 700 480 1937-38 1,830 690 480 1938-39 1,570 690 530 1939-40 1,600 710 530 1940-41 1,580 760 490 1941-42 1,480 870 530 1942-43 1,700 1,050 610 1943-44 1,940 1,110 610 1944-45 1,740 1,110 Surface Outflotv During 1 1 -Year Period Estimated surface outflow from Chino Basin averages 83,570 acre- feet annually. Of this 83,330 acre-feet is to Santa Ana Narrows Basin, and is the difference between measured discharge at Station 15822 and estimated inflow to that basin between its upper boundary and the station. The remaining 240 acre feet is to Riverside- Arlington Area, and the estimate is based on the assumption that within the area tributary to Station 16953, 50 percent of the inflow from Rialto Basin, 75 percent of the inflow from 1,310 acres of tributary hills and 1 percent of the precipitation on 6,750 acres of valley land in Chino Basin enters Santa Ana River above that station. Subsurface Outflotv to Santa Ana Narrows Basin In 1939, during early stages of construction of Prado Dam on Santa Ana River, Paul Bailej^, Engineer for Orange County Water District, conducted experiments to determine underflow at or just upstream from the dam site. From measurements of extractions of water from deep pits across the canyon floor, and observation of water table fluctuations in a series of test wells, he concluded that underflow was greater than 2.75 second-feet, but less than 4.00 second-feet. It is believed that the true value of subsurface outflow to Santa Ana Narrows Basin is somewhat less than the average of the above two observations, and an estimated annual value of 2,400 acre-feet is used herein for both 11-year and long-time average subsurface outflow at Prado. SOUTH COASTAL BASIN INVESTIGATION 237 Stchsurface Outflow to Spadra Basin Assuming that all items involved have been correctly evaluated, subsurface outflow to Spadra Basin during the 11-year period, must, in accordance with principles set forth in Chapter V, have averaged 710 acre-feet annually, as derived in Table 195. It is improbable that the actual subsurface outflow at this point is any less than this, and it is probably not significantly greater so far as evaluation of overdraft is concerned. A decrease of 0.1 foot in value of unit consumptive use assigned garden and field crops in Chino Basin alone would increase derived subsurface outflow by about 1,700 acre-feet, with no change i§ estimated overdraft. A similar decrease in value for avocado and citrus would increase calculated outflow by 2,250 acre-feet, and decrease esti- mated overdraft by only about 40 acre-feet. TABLE 19 5. ESTIMATED AVERAGE ANNUAL SUBSURFACE OUTFLOW FROM CHINO TO SPADRA BASINS DURING THE 11-YEAR PERIOD, 1927-28 TO 1937-3 8, INCLUSIVE Acre-feet Water entering basin Precipitation '. 205,960 Surface inflow • 68,490 Subsurface inflow 22,660 Import 39,150 Water coming from storage in basin 22,810 Total 359,070 Water leaving basin, other than by underflow to Spadra Basin Surface outflow 83,570 Subsurface outflow 2,400 Export 1,930 Consumptive use 270,460 Total 358,360 Subsurface Outflow — to Spadra Basin 710 Rising Water Originating in Chino Basin Discharge of Santa Ana River, measured at Station 15822 near Prado throughout the 11-year period, averaged 84,760 acre-feet annu- ally. It included all inflow to the river originating in runoff from moun- tains and hills tributary to Santa Ana Narrows Basin above the station, surface and subsurface inflow from Temescal Basin and Riverside- Arlington Area, water flowing across the surface of Chino Basin, and rising water from Chino Basin. All of these items but the last two are evaluated in discussion of the basins involved. Surface outflow from Chino Basin in Santa Ana River, other than rising water and that orig- inating in above-named basins, includes part of the inflow from directly tributary mountains and hills, runoff originating in precipitation on valley and folded land overlying the basin, and part of the outflow from Claremont Heights, Pomona, Cucamonga and Rialto Basins. Inflow from mountains directly tributary to Chino Basin is in small streams which seldom flow far into the basin. The distance from the 238 DIVISION OF WATER RESOURCES mouths of their canyons to Santa Ana River averages 15 miles. Spread- ing grounds on cones below Deer and Day Canyons augment natural percolation from these streams. While the residue is in part carried on paved roads extending southward across the basin, average outflow is relatively small, and is estimated at 5 percent of inflow. The greater part of inflow from directly tributary hills is into Chino Creek, which follows the northeasterly toe of Puente Hills for about 12 miles. Soil flanking these hills is hesiYj, and in lower reaches of the stream the water table is near the surface. Inflow from hills west of Riverside soon reaches the river. Outflow in Santa Ana River of water originating in the directly tributary hills is estimated to be 40 percent of the inflow therefrom. Of precipitation on valley land overlying Chino Basin, 1 percent is estimated to reach Santa Ana River at Station 15822 as outflow, together with 5 percent of precipitation on folded lands. Inflow from Claremont Heights Basin is in San Antonio Creek, which flows in an unpaved channel about seven miles to the upper reaches of Chino Creek. That from Pomona Basin crosses the boundary in streets and small channels, which carry it either to San Antonio or Chino Creeks. Outflow in Santa Ana River from these two basins is estimated at 40 percent of inflow. Inflow from Cucamonga Basin is in Cucamonga Creek, which in times of great flood, flows in a poorly-defined channel 10 miles south to Santa Ana River. Inflow from Riaito Basin is in several small channels which enter the basin about 12 miles from the river. Only 5 percent of inflow from Cuca- monga and Riaito Basins is estimated to reach Prado. Subtracting the sum of all other increments, as shown in Table 196, from the measured surface discharge at Prado gaging station, results in an estimated increment of rising water originating in Chino Basin which averages 17,910 acre-feet annually during the 11-year period. This is the net value after all consumptive use along the river between Riverside Narrows and the lower boundary of the basin has been subtracted. SOUTH COASTAL BASIN INVESTIGATION 239 TABLE 196. ESTIMATED AVERAGE ANNUAL RISING WATER ORIGINATING IN CHINO BASIN DURING THE 11-YEAR PERIOD, 1927-28 TO 1937-38, INCLUSIVE Acre- feet Surface discharge in Santa Ana River at Prado 84,760 Inflow to Santa Ana River below Riverside Narrows From mountains and hills tributary to Santa Ana Narrows Basin 1,250 From Temescal Basin To Santa Ana Narrows Basin 180 To Chino Basin Surface 1 3,260 Subsurface -^ 8,770 From Riverside-Arlington Area At Riverside Narrows Surface 47,170 Subsurface 500 Near Arlington, surface 800 From Chino Basin, excluding rising water Originating in directly tributary mountains 420 Originating in directly tributary hills 1,020 Originating in precipitation on valley and folded land 2,000 Originating in surface inflow from other basins Claremont Heights 1,190 Pomona 150 Cucamonga 60 Rialto 80 Subtotal 66,850 Rising Water Originating in Chino Basin 17,910 * Includes rising water in lower portion of Temescal Basin. Long-time Average Annual Surface Outflow During any considerable period of time there is no net change in storage in the immediate vicinity of Santa Ana River between Riverside Narrows and Prado. Therefore during the 32- and 21-year periods all water which enters the river between those points and is not consumed there must flow out of Chino Basin into Santa Ana Narrows Basin, either in or beneath the river. This includes flow across the surface of Chino Basin from the north, the basis for estimate of which is stated in the preceding article, rising water originating in Chino Basin which is assumed the same in all three periods, and surface and subsurface inflow from Riverside-Arlington Area and Temescal Basin which have been evaluated as outflow from those areas. Of this, 2,400 acre-feet leaves Chino Basin as underflow, and the remainder, averaging 116,040 acre-feet annually in the 32-year period and 88,300 acre-feet in the 21-year period, flows out in Santa Ana River. Assuming the ratio of runoff to pre- cipitation to be the same in the 32- and 21-year periods as during the 11-year period, estimated surface outflow from Chino Basin to Riverside- Arlington Area averages 240 acre-feet and 250 acre-feet, respectively, in the two periods. 240 DIVISION OF WATER RESOURCES Twenty-one year mean annual discharge at Prado gaging station under present conditions, estimated on the above basis, is 89,770 acre-feet, as compared with the historic 21-3^ear mean of 97,890 * acre-feet. Con- sumptive use in basins upstream from the station has increased, and some water has come out of storage during the 21-year period, so the comparison provides a check on the assumptions made. TABLE 197. ESTIMATED SURFACE OUTFLOW FROM CHINO BASIN Average annual for 32-year period, 1904-0 5 to 193 5-3 6, inclusive, and 21 -year period, 1922-23 to 1942-43, inclusive (Acre-feet) S2-year 21-year period peirod To Santa Ana Narrows Basin Estimated, originating in Directly tributary mountains 510 440 Directly tributary hilis 1,030 1,040 Precipitation on valley and folded land 2,020 2,040 Rising water originating in Chino Basin 17,910 17,910 Surface inflow from other basins Claremont Heights 780 800 Pomona 160 160 Cucamonga — 70 50 Rialto 80 90 Riverside-Arlington Area At Riverside Narrows — 77,230 52,220 Near Arlington 770 810 Temescal 4,380 3,040 Subsurface inflow from other basins Riverside-Arlington Area 500 500 Temescal 13,000 11,600 Total 118,440 90,700 Subsurface 2,400 2,400 120 130 30 30 90 90 240 250 Surface outflow at Prado 116,040 88,300 To Riverside-Arlington Area Surface, originating in Surface inflow from Rialto Basin Directly tributary hills Precipitation on valley land Total surface outflow to Riverside- Arlington Area__ Total Surface Outflow — from Chino Basin 116,280 88,550 Overdraft Assuming that the 21-year period is the cycle of long-time mean supply, estimated annual overdraft is 17,780 acre-feet, as derived in Table 198. If 32-year mean values are substituted in the table, the derived overdraft is 17,360 acre-feet. * Measured discharge corrected for inflow between stations 15822 and 15851A since 19 40-41. SOUTH COASTAL BASIN INVESTIGATION 241 TABLE 198. ESTIMATED ANNUAL OVERDRAFT IN CHINO BASIN UNDER PRESENT CONDITIONS ASSUMING THE 21 -YEAR PERIOD, 1922-23 TO 1942-43, INCLUSIVE, TO BE ONE OF LONG-TIME MEAN SUPPLY (Acre-feet) Estimated Actual long-time 11-year lean annual base under period present average Differ- conditions annual ence Average annual drop in storage during base period _ 22,810 Items tending to increase the drop Consumptive use 273,740 270,400 3,280 Export __ 2,820 1,930 890 Surface outflow 88,550 83.570 4,980 Subsurface outflow 3,110 3,110 Subtotal to be added 9,150 Items tending to decrease the drop Precipitation 210,150 205,960 4,190 Import 42,040 39,150 2,890 Surface inflow 72,760 68,490 4,270 Subsurface inflow.. 25,490 22,660 2,830 Subtotal to be subtracted 14,180 OVEEDRAFT 17,780 IRVINE BASIN (33d) Irvine Basin * occupies the extreme southeasterlj^ portion of the Coastal Plain, and covers about 46 square miles. It is bounded on the northeast by foothills of Santa Ana Mountains, on the southeast by South Coastal Basin boundary, on the southwest and south by San Joaquin Hills, on the west by East Coastal Plain Pressure Area, and on the north- west by Santa Ana Forebay Area. Topography of most of the surface is smooth, with slope generally toward the west averaging 80 feet per mile. Along bordering hills and in the extreme southeasterly portion it is more irregular, with a somewhat steeper slope toward the axis of the valley. Elevations range from 15 to 600 feet above sea level. Soils covering the surface range from lighter members of the Hanford series through Ramona sandy loam to Yolo clay adobe. The last is quite impervious. Domestic development occupies about 2 percent of the area, about 63 percent is devoted to agriculture, and the remainder is in a more or less natural state. Irrigated culture is about evenly divided between garden and field crops, and orchards, the greater part of the latter being citrus. The local water supply, utilized almost entirelj^ through pumping from ground water, originates in precipitation on valley lands, inflow from 25,240 acres of hills directly tributary to the basin, and inflow on the surface from Santa Ana Forebay Area. Imported water provides a relatively large addition to the supply. * There is no physical barrier to movement of ground water into the pressure area, and the classification as a separate basin is for convenience only. 16—71061 242 DIVISION OF WATER RESOURCES A considerable part of surface inflow and runoff originating in precipitation on the valley flows out into the pressure area of East Coastal Plain, together with relatively large underflow. A small amount of water is exported to Santa Ana Forebay Area, and there is some sewage outflow to the ocean. In this basin, long-time mean annual net supply under present con- ditions is less than present annual demand, so an overdraft exists. Evaluation of items required * to estimate its amount follows. Inflow Assuming that 10 percent of precipitation on the hills runs off, esti- mated annual inflow from 25,240 acres of hills directly tributary to the basin averages 3,390 acre-feet during the 21-year period, and 3,290 acre- feet during the 11-year period.! Estimated annual inflow on the surface from Santa Ana Forebay Area averages 490 acre-feet in the 21-year period, and 480 acre-feet during the 11-year period. Total estimated inflow from all sources averages 3,880 and 3,770 acre-feet annually in the respective periods. Subsurface inflow, other than that relatively small amount included with surface inflow from the hills, is considered negligible. I'mport In Table 199 estimated imports of water for each year since 1927-28 are presented. There is no import of sewage. Water is imported from East Coastal Plain Pressure Area, Santa Ana Forebay Area, Santiago Basin, and from Colorado River, and is from both gravity and pumped sources. During the 11-year period an annual average of 7,300 acre-feet was imported, of which 2,510 acre-feet was from Santiago Creek and Reservoir. It is estimated that average annual import of water under present conditions is 9,440 acre-feet. Average annual import from Santa Ana Forebay Area under present conditions is assumed to equal the historic average for the four-year period, 1941-42 to 1944-45, inclusive. Tliat from Colorado River and from East Coastal Plain Pressure Area is assumed the same as in 1944-45. Import from Santiago Basin consists of diversions from Santiago Reservoir and Creek, and from Fremont Canyon. The estimate of that from the reservoir is based on an operation study carried through the 21-year period, and on established rights to releases. Average annual import by diversion from Fremont Canyon and from Santiago Creek below the reservoir is assumed to equal the historic average for the 13-year period, 1932-33 to 1944-45, inclusive. TABLE 199. IMPORT TO IRVINE BASIN Year Acre-feet Year Acre-feet Year Acre- feet 1027-28 6,680 1933-34 8,600 1939-40 8,870 1928-29 5,130 1934-35 5,820 1940-41 9,290 1929-30 5,270 1935-36 7,350 1941-42 11,810 1930-31 5,330 1936-37 8,980 1942-43 10,620 1931-32 5,990 1937-38 11,830 1943-44 10,720 1932-33 9,280 1938-39 11,080 1944-45 10,670 * Values of change in storage and precipitation, also required, are presented in Tables 5 and 7. t If runoff from hills is assumed to follow the same regimen of flow as Santa Ana River, average annual inflow from that source for the 11-year period is 3,330 acre-feet. SOUTH COASTAL BASIN INVESTIGATION 243 Consuw-ptive Use In Table 200 estimates of consumptive use based on culture surveys conducted by the Division of Water Resources in 1932 and 1942 are presented. Unit values are discussed in Chapter V. A small part of the City of Santa Ana and all of Tustin overlie the basin. Light brush, weeds and grass cover the unused lands. TABLE 200. ESTIMATED AVERAGE ANNUAL CONSUMPTIVE USE IN IRVINE BASIN Type of culture Valley area Garden and field Avocado and citrus Deciduous Alfalfa Domestic and industrial. Unirrigated 21-year period 11-year period Subtotal 21-year period 11-year period Hill area Garden and field _. Avocado and citrus Subtotal Grand total 21-year period — 11-year period Unit con- sumptive 1932 19.\ \2 use, feet Acres Acre-feet Acres Acre- feet 1.3 3,785 4,920 9.380 12,194 1.9 7,396 14,052 7,933 15,073 1.7 1,666 2,832 1,289 2,191 2.5 45 112 1.4 599 839 619 867 16,205 10,475 — — — . ^ 0.9 „__ 9,428 0.886 14,358 29,696 29,696 0» 0.7" 30 312 342 30,038 37,113 218 218 37,331 30 342 372 30,068 39,753 239 239 39,992 * Difference between irrigated culture and natural vegetation. Export In Table 201 estimated exports of water and sewage for each year since 1927-28 are presented. Water is exported to Santa Ana Forebay Area, while sewage goes directly to the ocean. During the 11-year period an annual average of 140 acre-feet of water and 180 acre-feet of sewage was exported, a total of 320 acre-feet. Estimated average annual export of water under present condi- tions is 160 acre-feet, and of sewage 300 acre-feet, a total of 460 acre-feet. It is assumed that the historic export during the four-year period, 1941-42 to 1944-45, inclusive, and that during 1944-45 alone, represent present average annual exports of water and sewage, respectively. 244 DIVISION OF WATER RESOURCES TABLE 201. EXPORT FROM IRVINE BASIN (Acre-feet) Year Water Sewage Year Water Sewage 1927-28 150 180 1936-37 160 220 1928-29 150 180 1937-38 120 240 1929-30 150 170 1938-39 130 250 1930-31 150 170 1939-40 90 250 1931-32 160 170 1940-41 100 230 1932-33 140 160 1941-42 40 220 1933-34 100 160 1942-43 210 260 1934-35 140 190 1943-44 220 310 1935-36 110 190 1944-45 160 300 Surface Outflow Outflow on the surface includes part of the inflow from directly tributary hills, part of that from Santa Ana Forebaj^ Area and runoff originating in precipitation on the overlying valley. Assuming that 50 percent of inflow from directly tributary hills, 75 percent of inflow from Santa Ana Forebay Area, and 5 percent of precipitation on overlying valley land leave the basin, estimated outflow averages 3,830 acre-feet and 3,720 acre-feet in the 21- and 11-year periods, respectively, as derived in Table 202. TABLE 202. SURFACE OUTFLOW FROM IRVINE BASIN Average annual for 21 -year period, 1922-23 to 1942-43, inclusive, and 11 -year period, 1927-28 to 1937-38, inclusive (Acre-feet) 21-year 11-year period period Estimated, originating in Directly tributary hills 1,700 1,650 Inflow from other basins 370 360 Precipitation on valley and folded laud 1,760 1,710 Total 3,830 3,720 Overdraft Assuming that the 21-year period is the cycle of long-time mean supply, estimated annual overdraft is 2,740 acre-feet, as derived in Table 203. SOUTH COASTAL BASIN INVESTIGATION 245 TABLE 203. ESTIMATED ANNUAL OVERDRAFT IN IRVINE BASIN UNDER PRESENT CONDITIONS ASSUMING THE 21 -YEAR PERIOD, 1922-23 TO 1942-43, INCLUSIVE, TO BE ONE OF LONG-TIME MEAN SUPPLY (Acre-feet) Estimated Actual long-time 11-year mean annual hase under period present average Differ- conditions annual ence Average annual drop in storage during base period 3,120 Items tending to increase the drop Consumptive use 39,990 37,330 2,660 Export 460 320 140 Surface outflow 3,830 3,720 110 Subtotal to be added 2,910 Items tending to decrease the drop Precipitation 35,200 34,160 1,040 Surface inflow 3,880 3,770 110 Import 9,440 7,300 2,140 Subtotal to be subtracted 3,290 Overdraft 2,740 Subsurface Outflow Assuming that all items involved have been correctly evaluated, subsurface outflow during the 11-year base period, must in accordance V7ith principles set forth in Chapter V, have averaged 6,980 acre-feet annually, as derived in Table 204. TABLE 204. ESTIMATED AVERAGE ANNUAL SUBSURFACE OUTFLOW FROM IRVINE BASIN DURING THE 11 -YEAR PERIOD, 1927-28 TO 1937-38, INCLUSIVE Acre-feet Water entering basin Precipitation 34,160 Surface inflow 3,770 Import 7,300 Water coming from storage in basin 3,120 Subtotal 48,350 Water leaving basin on surface Surface outflow 3,720 Exported water 140 Exported sewage 180 Consumptive use 37,330 Subtotal 41,370 Subsurface Outflow — to East Coastal Plain Pressure Area 6,980 246 DIVISION OF WATER RESOURCES LOWER SANTA ANA RIVER AREA Santa Ana Forebay Area (3 3c) East Coastal Plain Pressure Area (3 3f ) Yorba Linda Basin (3 5) Santa Ana Narrows Basin (37) Santiago Basin (50) There is no physical barrier to movement of ground water from Santa Ana Narrows and Santiago Basins into Santa Ana Forebay Area, or from the forebay area into East Coastal Plain Pressure Area. A large part of the supply to Yorba Linda Basin is imported from Santa Ana Narrows Basin. Because of these natural or artificial interconnections between its component parts, the group of basins comprising the Lower Santa Ana River Area is treated as a unit. Topography of most of the area, including nearly all of Santa Ana Forebay Area and the pressure area is relatively smooth, with average slope of less than 20 feet per mile. The direction of slope changes gradu- ally from westerly in the vicinity of the boundary between Santa Ana Forebay Area and Yorba Linda Basin, to southerly in the vicinity of Santa Ana. Topography of Yorba Linda Basin is rolling and irregular. In Santa Ana Narrows Basin relatively smooth bottom lands are bordered by steeply sloping alluvium flanking the hills on either side. In Santiago Basin topography is generally rolling, but rougher than in Yorba Linda Basin. Elevations range from sea level to 1,100 feet above. Virtually all of Santa Ana Forebay Area west of Santa Ana River is covered with soils of the Hanford series. Farther south extensive areas of the finer textured Chino soils appear. East of the river Yolo soils predominate, with considerable areas of Ramona soils on mesa lands nearer the coast. In Yorba Linda and Santiago Basins, Yolo and Ramona soils, both only moderately permeable, predominate. In Santa Ana Narrows Basin these soils cover the steeper lands, and lighter Hanford soils the bottom lands. Municipal development occupies about 8 percent of the area, about 60 percent is covered by irrigated crops, and the remainder is either in a natural state or temporarily lying fallow. This area resembles Lower Los Angeles and San Gabriel Rivers Area in that downward percolation into the pumping aquifers of East Coastal Plain Pressure Area is negligible. The local water supply, utilized by both large gravity diversions and extensive pumping from the ground water, originates in precipitation on the valley, inflow from 42,670 acres of mountains and 53,250 acres of hills directly tributary to the non- pressure portion of the area, surface inflow from La Habra, Chino and Temescal Basins, and subsurface inflow from Chino Basin. Some water is imported, the greater part of it for municipal use. While a large part of the inflow is rising water in Santa Ana River, regulated in upstream ground water basins to a fairly uniform flow, there is still considerable outflow onto the pressure area and thence to the ocean. Water and sewage are exported from the nonpressure portion of the area in relatively large amount. For Lower Santa Ana River Area as a whole, long-time mean net supply under present conditions is less than present annual demand, so an overdraft exists. In estimating the amount of this overdraft significant items are change in storage, precipitation on, and surface inflow and SOUTH COASTAL BASIN INVESTIGATION 247 import to the nonpressure portion of the area ; surface outflow, consump- tive use and export leaving the nonpressure portion ; and extraction from the pressure area. Evaluation of each of these items * follows. Inflotv to Nonpressure Portion of Area Since deep percolation in the pressure area is negligible, only that inflow entering the nonpressure portion of the area is here considered. Estimated annual surface inflow averages 110,280 acre-feet and 102,860 acre-feet in the 21-year and 11-year periods, respectively, as derived in Table 205. None of the inflow from directly tributary mountains and hills is measured at point of entry. Assuming, however, that precipitation on valley lands tributary to Santiago Creek above Station 15728 is balanced by consumptive use on those lands and underflow at the station, metered discharge at the station, corrected for upstream diversions and regula- tion, measures the inflow from mountains and hills above that point. The estimate of inflow from the remaining 6,050 acres of mountains and 40,440 acres of hills is based on the assumption that 10 percent of the precipitation thereon runs off. Inflow from Chino and Temescal Basins in Santa Ana River and from La Habra Basin in Brea and East Fullerton Creeks, is discussed in connection with outflow from the respective basins. Subsurface inflow, other than that indicated by note in Table 205, is from Chino Basin and is estimated to amount to 2,400 acre-feet annually. TABLE 205. SURFACE INFLOW TO NONPRESSURE PORTION OF LOWER SANTA ANA RIVER AREA Average annual for 21-year period, 1922-23 to 1942-43, inclusive, and 11-year period, 1927-28 to 1937-38, inclusive (Acre-feet) 21-year 11-year period period From directly tributary mountains and hills Measured during part of period 14,320 12,300 Estimated * 6,240 6,050 From other basins La Habra 1,240 1,000 Chino and Temescal 88,480 83,510 Total 110,280 102,860 « Includes a relatively small amount of underflow. Import to Nonpressure Portion of Area In Table 206 estimated values of import of water from East Coastal Plain Pressure Area, from Irvine and La Habra Basins, and from Colo- rado River to the nonpressure portion of Lower Santa Ana River Area for each year since 1927-28, are presented. There is no import of sewage. During the 11-year period an average of 1,320 acre-feet was imported annually. Assuming that the historic average annual imports from La Habra and Irvine Basins during the four-year period, 1941-42 to 1944-45, inclu- * Values of change in storage and precipitation are presented in Tables 5 and 7. 248 DIVISION OF WATER RESOURCES sive, and the 1944-45 imports from Colorado River and from East Coastal Plain Pressure Area represent average annual imports under present conditions, the value so estimated is 4,680 acre-feet. TABLE 206. IMPORT TO NONPRESSURE POPvTiON OF LOWER SANTA ANA RIVER AREA Year Acre- feet Year Acre-feet Year Acre-feet 1927-28 1,400 1928-29 1,360 1929-30 1,410 1930-31 1,420 1931-S2 1,330 1932-33 1,250 1933-34. 1934-35. 1935-36. 1936-37. 1937-38. 1938-39. 1,220 1.210 1.270 1,290 1,310 1,340 1939-40 1,300 1940-41 2,440 1941-42 1,940 1942-43 2.370 1943-44 2,690 1944-45 4.690 Consumptive Use in Nonpressure Portion of Area In Table 297 estimates of consumptive use based on culture surveys conducted by the Division of Water Resources in 1932 and 1942 are presented. Unit values are discussed in Chapter V. The Cities of Anaheim and Orange, and portions of Santa Ana and FuUerton, overlie the area. Acreage devoted to crops other than citrus is relatively very small. Unirri- gated lands are covered for the most part with grass and weeds, with water-loving vegetation bordering the river in Santa Ana Narrows Basin. TABLE 207. ESTIMATED AVERAGE ANNUAL CONSUMPTIVE USE IN NON- PRESSURE PORTION OF LOWER SANTA ANA RIVER AREA Unit con- sumptive 1932 1942 Type of culture use, feet Acres Acre-feet Acres Acre-feet Valley and folded area Garden and field__— — 1.3 1,454 1,890 1,249 1,624 Avocado and citrus 1.9 43,986 83,573 45,343 86,152 Deciduous 1.7 4,200 7,140 2,480 4,216 Alfalfa and irrigated grass 2.5 146 365 256 640 Domestic and industrial 1.4 4,109 5,753 4,284 5,998 River-bed brush (water-loving) ___ 4.0 1,100 4,400 1,100 4,400 Unirrigated 17,479 17,762 21-vear period 0.9 15,986 11-year period 0.886 15,486 Evaporation from Santiago Reservoir " -_ 540 1,050 Subtotal 72,474 72,474 21-year period 120,066 11-year period 119,147 Hill Area Garden and field O.O*" 95 85 Avocado and citrus 0.7" 1,163 814 1,198 839 Domestic and industrial 0.2'' 38 8 98 20 Subtotal 1,296 822 _1,381 859 Grand total 73,770 73,855 21-year period 120,925 11-year period 119,969 » Difference between evapora* ion from water surface and rainfall on reservoir surface. *> Difference between irrigated culture and natural vegetation. SOUTH COASTAL BASIN INVESTIGATION 249 Export FroTtt Nonpressiire Portion of Area In Table 208 estimated values of exports of water and sewage from the nonpressiire portion of Lower Santa Ana River Area for each year since 1927-28 are presented. Water is exported to Irvine Basin and to East Coastal Plain Pressure Area, and sewage goes directly to the ocean. During the 11-year period an annual average of 9,270 acre-feet of water and 3,120 acre-feet of sewage was exported, a total of 12,390 acre-feet. Export of water from Santiago Basin to Irvine Basin consists of diversions from Santiago Creek and Reservoir, and from Fremont Can- yon. Based upon a study of operation of Santiago Reservoir for the 21-year period, and upon established rights to releases from the reservoir, estimated export available annually from that source under present con- ditions averages 4,330 acre-feet. Average annual export by diversion from Fremont Canyon, and from Santiago Creek below the reserA^oir, is assumed to equal its historic average for the 13-year period, 1932-33 to 1944-45, inclusive. Mean annual export from Santa Ana Forebay Area to Irvine Basin and the pressure area is assumed the same as its historic average for the four-year period, 1941-42 to 1944-45, inclusive. Average annual sewage outflow under present conditions is assumed equal to its historic value for 1944-45. Estimated total annual export from the non- pressure portion of the area under present conditions is 16,390 acre-feet, consisting of 11,240 acre-feet of water, and 5,150 acre-feet of sewage. TABLE 208. EXPORT FROM NONPRESSURE PORTION OF LOWER SANTA ANA RIVER AREA (Acre-feet) Tear Water Seicage Year Water Sewage 1927-28 9,000 2,660 1936-37 — 10,700 3,9G0 1928-29 6,890 2,920 1937-38 13.640 4,800 1929-30 7,100 2,800 1938-39 12,830 4,660 1930-31 7,150 2,810 1939-40 10,550 4,650 1931-32 7,640 2.910 1940-41 10,620 4,720 1932-33 11,900 2,640 1941-42 14,060 4,830 1933-34 11,090 2,670 1942-43 12,670 4,600 1934-35 7,250 2,960 1943-44 12,410 5,070 1935-36 9,590 3,160 1944-45 12,050 5,150 Surface Outflow From Nonpressiire Portion of Area Outflow on the surface includes part of the inflow from directly tributary mountains and hills, a part of that from La Habra, Chino and Temescal Basins, and runoff originating in precipitation on overlying valley and folded land. It is estimated to average 25,510 acre-feet and 21,450 acre-feet annually in the 21- and 11-year periods, respectively, as derived in Table 209. While some error on the conservative side is no doubt introduced by so doing, it is assumed that long-time mean annual outflow in the river under present conditions is represented by the historical average annual flow, measured at Station 14495 during all but the first three months of the 21-year period. Studies indicate that operation of Prado Reservoir, completed in 1940, has reduced the annual discharge at Santa Ana little if any. Had Santiago Reservoir, completed in December, 1931, been in 250 DR'ISIOX OF WATER RESOURCES operation throughout the period, it is estimated that 21-year mean annual discharge at Station 15728 would have been reduced by about 1,000 acre- feet. Percolation between that station and Station 14495 would, however, also have been reduced, and inflow somewhat increased by cultural changes. The error introduced by assuming historical 21-year average and present long-time mean annual to be identical is therefore small. It is assumed that total discharge of East Fullerton Creek, measured at Stations 15611 or 1192 since 1930-31, and of Brea Creek, measured at Stations 1171 or 1172 during the same period, flows out of the nonpressure portion of the area. Runoff in these creeks prior to 1930-31 is estim^ated from its relationship ^vith precipitation as represented by the Coastal Plain Group. From that part of Santa Ana Forebaj' Area which is tributary to Irvine Basin, outflow is estimated to consist of 90 percent of inflow from directly tributary hills, and 5 percent of precipitation on valley land. From the remainder of the f orebay area not tributary to gaging stations, outflow is estimated as 5 percent of precipitation on valley land. Addi- tional outflow from the nonpressure portion of the area consists of an esti- mated 25 percent of unmeasured inflow to Santa Ana Forebay Area from Yorba Linda Basin. Such inflow is estimated as 10 percent of precipi- tation on hills, and 5 percent of that on valley and folded land. TABLE 209. SURFACE OUTFLOW FROM NONPRESSURE PORTION OF LOWER SANTA ANA RIVER AREA Average annual for 21-year period, 1922-23 to 1942-43, inclusive, and 11-year period, 1927-28 to 1937-3 8, inclusive (Acre-feet) 21-year 11-year period period Measured during all or part of period Santa Ana River 21,070 17,350 East Fullerton Creek 460 430 Brea Creek 1,020 800 Estimated, originating in Directly tributary hills 720 700 Precipitation on valley and folded land 2,240 2,170 Total 25,510 21,450 Extractions From East Coastal Plain Pressure Area Under the procedure followed in estimating- the difference between present and 11-year average extractions from the pressure area as set forth in Table 210, a decrease of 20 acre-feet has occurred. "While use of water within the area has increased, the introduction in 19-43-44 of Colo- rado River water to the service areas of the City of Santa Ana and South Coast Municipal Utility District has balanced the increased demand. A relatively small part of the total extraction has been measured, but this portion includes that of the principal municipal and industrial producers whose 1944-45 extractions were significantly different than those of the 11-year period. These are presented first in the table. SOUTH COASTAL BASIN INVESTIGATION 251 Acreage devoted to garden and field crops, constituting nearly two- thirds of the irrigated land in East Coastal Plain Pressure Area, has varied from year to year during and since the 11-year period, but has demonstrated no consistent trend. Acreage in citrus and alfalfa increased consistently until 1937-38, and has since remained almost constant, while deciduous acreage has decreased consistenth^ during and since the 11-year period. In the second part of the table, the change in acreage between 1932 and 1942, assumed to represent the difference between the average for the ll-j^ear period and the present value, respectively, is multiplied b}' the estimated average duty for each of the three crops in which a consistent change has occurred. TABLE 210. ESTIMATED DIFFERENCE BETWEEN 11 -YEAR AVERAGE AND PRESENT ANNUAL EXTRACTIONS FROM EAST COASTAL PLAIN PRESSURE AREA 11-year average, 19^^4-45, Decrease, acre-feet acre-feet acre-feet Measured extractions Municipalities 5,510 3,120 2,390 Districts and water companies 3,540 3,870 — 330 Industrial users 1,660 1,770 —110 Cadet Center 400 —400 Decrease in measured extractions 1,550 Acres served Duty, 1932 19Jf2 Decrease feet Unmeasured extractions Citrus 12,811 13,669 —858 1.3 —1,120 Alfalfa 5,599 6,109 —510 1.8 —920 Deciduous 1,181 546 635 0.8 510 Decrease in unmeasured extractions — 1,530 Total decrease in extractions 20 Subsurface Outflow From East Coastal Plain Pressure Area While the boundary between Bast Coastal Plain Pressure Area and Central Coastal Plain does not follow a physical barrier to movement of ground water, contours of the water table indicate that very little ground water crosses the general course of Coyote Creek in either direction. Creation of a gradient sufficient to produce appreciable underflow could only result from excessive lowering of the water table on the downstream side of the selected boundar3^ Such lowering did not occur during or since the 11-year period, nor is it considered probable that it will occur in the future. Contours of the water table adjacent to the ocean indicate that subsurface outflow in that direction, during and since the 11-year period, has been negligible. Overdraft Assuming that the 21-year period represents a cycle of long-time mean suppl}', estimated annual overdraft is 10,240 acre-feet, as derived in Table 211. 252 DIVISION OF WATER RESOURCES TABLE 211. ESTIMATED ANNUAL OVERDRAFT IN LOWER SANTA ANA RIVER AREA UNDER PRESENT CONDITIONS ASSUMING THE 21 -YEAR PERIOD, 1922-23 TO 1942-43, INCLUSIVE, TO BE ONE OF LONG-TIME MEAN SUPPLY (Acre-feet) Estimated Actual long-time 11-year mean annual base under period present average Differ- conditions annual ence 14,690 Average annual drop in storage during base period Items tending to increase the drop Nonpressure portion of area Consumptive use 120,920 119,970 950 Export 16,390 12,390 4,000 Surface outflow 25,510 21,450 4,060 Pressure area Extractions — 20 Subsurface outflow Subtotal to be added Items tending to decrease the drop Nonpressure portion of area Precipitation 89,460 86,800 2,660 Surface inflow 110,280 102,860 7,420 Import 4,680 1,320 3,360 Subtotal to be subtracted Overdraft 8,990 13,440 10,240 PUBLICATIONS DIVISION OF WATER RESOURCES PUBLICATIONS OF THE DIVISION OF WATER RESOURCES DEPARTMENT OF PUBLIC WORKS STATE OF CALIFORNIA When the Department of Public Works was created in July, 1921, the State Water Commission was succeeded by the Division of Water Rights, and the Department of Engineering w^as succeeded by the Division of Engineering and Irrigation in all duties except those pertaining to State Architect. Both the Division of Water Rights and the Division of Engineering and Irrigation functioned until August, 1929, when they were consolidated to form the Division of Water Resources. The Water Project Authority was created by the Central Valley Project Act of 193 3. STATE WATER COMMISSION ♦First Pweport, State Water Commission, March 2 4, to November 1, 1912. ♦Second Report, State AVater Commission, November 1, 1912, to April 1, 1914. ♦Biennial Report, State Water Commission, March 1, 1915, to December 1, 1916. ♦Biennial Report, State Water Commission, December 1, 1916, to September 1, 1918. ♦Biennial Report, State Water Commission, September 1, 1918, to September 1, 1920. DIVISION OF WATER RIGHTS ♦Bulletin No. 1 — Hydrographic Investigation of San Joaquin River, 1920-1923. ♦Bulletin No. 2 — Kings River Investigation, Water Master's Report, 1918-1923. ♦Bulletin No. 3 — Proceedings First Sacramento-San Joaquin River Problems Confer- ence, 1924. ♦Bulletin No. 4 — Proceedings Second Sacramento-San Joaquin River Problems Confer- ence, and Water Supervisors' Report, 1924. ♦Bulletin No. 5 — San Gabriel Investigation — Basic Data, 1923-1926. Bulletin No. 6 — San Gabriel Investigation — Basic Data, 1926-1928. Bulletin No. 7 — San Gabriel Investigation — Analysis and Conclusions, 1929. ♦Biennial Report, Division of Water Rights, 1920-1922. ♦Biennial Report, Division of Water Rights, 19 22-192 4. Biennial Report, Division of Water Rights, 192 4-19 26. Biennial Report, Division of T\'ater Rights, 1920-1928. DEPARTMENT OF ENGINEERING ♦Bulletin No. 1 — Cooperative Irrigation Investigations in California, 1912-1914. ♦Bulletin No. 2 — Irrigation Districts in California, 1S87-1915. Bulletin No. 3 — Investigations of Economic Duty of Water for Alfalfa in Sacramento Valley, California, 1915. ♦Bulletin No. 4 — Preliminary Report on Conservation and Control of Flood Waters in Coachella Valley, California, 1917. ♦Bulletin No. 5 — Report on the Utilization of Mojave River for Irrigation in Victor Valley, California, 1918. ♦Bulletin No. 6 — California Irrigation District L^fws, 1919 (now obsolete). Bulletin No. 7 — Use of Water from Kings River, California, 1918. ♦Bulletin No. 8 — Flood Problems of the Calaveras River, 1919. Bulletin No. 9 — Water Resources of Kern River and Adjacent Streams and Their Utilization, 1920. ♦Biennial Repqrt, Department of Engineering, 1907-1908. ♦Biennial Report, Department of Engineering, 1908-1910. ♦Biennial Report, Department of Engineering, 1910-1912. ♦Biennial Report, Department of Engineering, 1912-1914. ♦Biennial Report, Department of Engineering, 1914-1916. ♦Biennial Report, Department of Engineering, 1916-1918. ♦Biennial Report, Department of Engineering, 1918-1920. DIVISION OF WATER RESOURCES Including Reports of the Former Division of Engineering and Irrigation ♦Bulletin No. 1 — California Irrigation District Laws, 1921 (now obsolete). ♦Bulletin No. 2 — Formation of Irrigation Districts, Issuance of Bonds, etc., 1922. Bulletin No. 3 — Water Resources of Tulare County and Their Utilization, 1922. Bulletin No. 4 — Water Resources of California, 1923. Bulletin No. 5 — Flow in California Streams, 1923. Bulletin No. 6 — Irrigation Requirements of California Lands, 1923. ♦Bulletin No. 7 — California Irrigation District Laws, 19 23 (now obsolete). ♦Bulletin No. 8 — Cost of Water to Irrigators in California, 1925. Bulletin No. 9 — Supplemental Report on Water Resources of California, 1925. ♦Bulletin No. 10 — California Irrigation District Laws, 1925 (now obsolete). Bulletin No. 11 — Ground Water Resources of Southern San Joaquin Valley, 1927. ♦ Reports and Bulletins out of print. These may be borrowed by your local library from the California State Library at Sacramento, California. (254) i SOUTH COASTAL BASIN INVESTIGATION 255 Bulletin No. 12 — Bulletin No. 13- Bulletin ♦Bulletin ♦Bulletin Bulletin Bulletin Bulletin Bulletin ♦Bulletin Bulletin ♦Bulletin Bulletin No. 14 No.18- No. 18 No. 18 No. 18 No. 18 No. 18 No. 18 No. 18 No. 18 No. 19 1931 Revision. 1933 Revision. 1935 Revision. Revision. Revision. 1937 1939 Bulletin No. 20 — Bullet Bullet Bullet Bullet ♦Bullet Bullet Bullet Bullet Bullet Bullet Bullet Bullet Bullet Bullet Bullet Bullet Bullet Bullet Bullet Bullet Bullet Bullet n No. n No. n No. n No. n No. n No. n No. n No. n No. n No. n No. n No. n No. n No. n No. n No. n No. n No. nNo. n No. n No. n No. 21 21 21 21 21 21 21 21 21 21 21 21 21 21 21 21 22 23 24 25 26 27 Bulletin No. 28 Bulletin Bulletin Bulletin Bulletin Bulletin Bulletin Bulletin Bulletin Bulletin Bulletin Bulletin No. 28 No. 29 No. 31 No. 3 2 No. 33 No. 34 No. 35 No. 36 No. 37 No. 38 No. 39 Bulletin No. 39 Bulletin No. 39 Bulletin No. 39 Bulletin No. 39 Bulletin No. 39 Bulletin No. 39 Bulletin No. 39 Bulletin No. 39 Bulletin No. 39 ♦Bulletin No. 39 Bulletin No. 39 Summary Report on the Water Resources of California and a Coor- dinated Plan for Their Development, 1927. —The development of the Upper Sacramento River, containing U. S. R. S. Cooperative Report on Iron Canyon Project, 1927. —The Control of Floods by Reservoirs, 1928. -California Irrigation District Laws, 1927, Revision. A — California Irrigation District Laws, 1929 Revision. B — California Irrigation District Laws, C — California Irrigation District Laws, D — California Irrigation District Laws, E — California Irrigation District Laws, F — California Irrigation District Laws, G — California Irrigation District Laws, 1941 Revision. H — Water Code, Divisions 10 and 11, Irrigation District Laws 1943. —Santa Ana Investigation, Flood Control and Conservation (with packet of maps), 1928. Kennett Reservoir Development, an Analysis of Methods and Extent of Financing by Electric Power Revenue, 1929. —Irrigation Districts in California, 1929. A — Report on Irrigation Districts in California for the year 1929. B — Report on Irrigation Districts in California for the year 1930. C — Report on Irrigation Districts in California for the year 1931. D — Report on Irrigation Districts in California for the year 1932. E — Report on Irrigation Districts in California for the year 1933. F — Report on Irrigation Districts in California for the year 1934. G — Report on Irrigation Districts in California for the year 1935. H — Report on Irrigation Districts in California for the year 1936. I — Report on Irrigation Districts in California for the year 1937. J — Report on Irrigation Districts in California for the year 1938. K — Report on Irrigation Districts in California for the year 1939. L — Report on Irrigation Districts in California for the year 1940. M — Report on Irrigation Districts in California for the year 1941. N — Report on Irrigation Districts in California for the year 1942. O — Report on Irrigation Districts in California for the year 1943. —Report on Salt Water Barrier (two volumes), 1929. —Report on Sacramento-San Joaquin AVater Supervisor, 1924-1928. —A proposed Major Development on American River, 1929. — Report to Legislature of 1931 on State Water Plan, 1930. Sacramento River Basin, 1931. Variation and Control of Salinity in Sacramento-San Joaquin Delta and Upper San Francisco Bay, 19 31. — Economic Aspects of a Salt Water Barrier Below Confluence of Sacra- mento and San Joaquin Rivers, 1931. A — Industrial Survey of Upper San Francisco Bay Area, 1930. —San Joaquin River Basin, 1931. —Santa Ana River Basin, 1930. —South Coastal Basin, a Cooperative Symposium, 1930. —Rainfall Penetration and Consumptive Use of Water in Santa Ana River Valley and Coastal Plain, 193 0. — Permissible Annual Charges for Irrigation Water in Upper San Joaquin Valley, 193 0. — Permissible Economic Rate of Irrigation Development in California, 1930. — Cost of Irrigation Water in California, 1930. — Financial and General Data Pertaining to Irrigation, Reclamation and Other Public Districts in California, 1930. —Report of Kings River Water Master for the Period 1918-1930. —South Coastal Basin Investigation, Records of Ground Water Levels at Wells, 1932. A — Records of Ground Water Levels at Wells for the Year 1932, Seasonal Precipitation Records to and including 1931-1932. (Mimeographed. ) -B — Records of Ground Water Levels at Wells for the Year 1933, Precipitation Records for the Season 19 3 2-33. (Mimeographed.) -C — Records of Ground Water Levels at Wells for the Year 1934, Precipitation Records for the Season 1933-34. (Mimeographed.) -D — Records for Ground Water Levels at Wells for the Year 193 5, Precipitation Records for the Season 1934-35. (Mimeographed.) -E — Records of Ground Water Levels at Wells for the Year 193 G, Precipitation Records for the Season 1935-36. (Mimeographed.) -F — Records of Ground Water Levels at Wells for the Year 1937, Precipitation Records for the Season 1936-37. (Mimeographed.) -G— Records of Ground Water Levels at Wells for the Year 193 8, Precipitation Record for the Season 1937-38. (Mimeographed.) -H — Records of Ground Water Levels at Wells for the Year 1939, Precipitation Records for the Season 1938-39. (Mimeographed.) -I — Records of Ground Water Levels at Precipitation Records for the Season -J — Records of Ground Water Levels at including San Jacinto and Antelope record. Precipitation records for the Season 1940-41. -K — Records of Ground Water Levels at Wells for the Year 1942 Precipitation Records for the Season 19 41-42. Wells for the Year 1940, 1939-40. (Mimeographed.) Wells for the Year 1941 ; Valleys from beginning of * Reports and Bulletins out of print. These may be borrowed by your local library from tlie California State Library at Sacramento, California. 256 DIVISION OF WATER RESOURCES Bulletin No. 39-L/ — Records of Ground Water Levels at Wells for the Year 1943. Precipitation Records for the Season 1942-43. Bulletin No. 40 — South Coastal Basin Investigation, Quality of Irrigation Waters, 1933. ♦Bulletin No. 40-A — South Coastal Basin Investigation, Detailed Analyses Showing Quality of Irrigation Waters, 1933. Bulletin No. 41 — Pit River Investigation, 1933. Bulletin No. 42 — Santa Clara Investigation, 1933. Bulletin No. 43 — Value and Cost of V^ater for Irrigation in Coastal Plain of Southern California, 1933. Bulletin No. 44 — V^ater Losses' Under Natural Conditions from Wet Areas in Southern California, 1933. Bulletin No. 45 — South Coastal Basin Investigation, Geology and Ground Water Storage Capactiy of Valley Fill, 1934. Bulletin No. 46 — Ventura County Investigation, 1933. Bulletin No. 46-A — Ventura County Investigation, Basic Data for the Period 1927 to 1932, inclusive. (Mimeographed.) Bulletin No. 47 — Mojave River Investigation, 1934. (Mimeographed.) ♦Bulletin No. 48 — San Diego County Investigation, 1935. (Mimeographed.) Bulletin No. 48-A — San Luis Rey River Investigation, 1936. (Mimeographed.) Bulletin No. 49 — Kaweah River — Flows, Diversions and Service Areas, 1940. Bulletin No. 5 — Use of Water by Native Vegetation, 19 42. Bulletin No. 51 — Irrigation Requirements of California Crops, 1945. Bulletin No. 52 — Salinas Basin Investigation. Bulletin No. 52-A — Salinas Basin Investigation — Basic Data. Bulletin No. 52-B — Salinas Basin Investigation — Summary Report, Bulletin 53 Biennial Report, Division of Engineering and Irrigation, 1920-1922. Biennial Report, Division of Engineering and Irrigation, 1922-1924. Biennial Report, Division of Engineering and Irrigation, 1924-1926. Biennial Report, Division of Engineering and Irrigation, 1926-1928. PAMPHLETS Dams Under Jurisdiction of the State of California, 1941. Water Code, 1943. Water Rights, Divisions 1, 2 and 4 of Water Code, 1943. Supervision of Dams, Division 3 of Water Code, 1943. State Water Plan, Authorities and Boards, Division 6 of W^ater Code, 1943. California Administrative Code, Title 23, Waters. Rules and Regulations Pertaining to Supervision of Dams in California, 1946. Rules, Regulations and Information Pertaining to Appropriation of Water in California, 19 46. Rules, Reguations and Information Pertaining to Determination Rights to the Use of Water in California, 19 46. Rules and Regulations pertaining to Protests and Hearings, 1946. COOPERATIVE AND MISCELLANEOUS REPORTS ♦Report of the Conservation Commission of California, 1912. ♦Irrigation Resources of California and Their Utilization (Bull. 254, Office of Exp. U. S. D. A.), 1913. ♦Report, State Water Problems Conference, November 25, 1916. ♦Report on Pit Pviver Basin, April, 1915. ♦Report on Lower Pit River Project, July 1915. ♦Report on Iron Canyon Project, California, 1914. ♦Report on Iron Canyon Project, California, May 1920. ♦Sacramento Flood Control Project (Revised Plans), 1925. Report of Commission Appointed to Investigate Causes Leading to the Failure of St. Francis Dam, 1928. P^eport of the California Joint Federal-State Water Resources Commission, 1930. Conclusions and Recommendations of the Report of the California Irrigation and Reclamation Financing and Refinancing Commission, 1930. ♦Report of California Water Resources Commission to the Governor of California on State Water Plan, 1932. ♦Booklet of Information on California and the State Water Plan Prepared for United States House of Representatives' Subcommittee on Appropriations, 1931. ♦Bulletin on Great Central Valley Project of State Water Plan of California Prepared for United Sta.tes Senate Committee on Irrigation and Reclama- tion, 1932. WATER PROJECT AUTHORITY Bulletin No. 1 — Publicly Operated Electric Utilities in Northern California, 1941. ♦Report on Kennett Power System of Central Valley Project, 1935. ♦Report on the Programiming of Additional Electric Power Facilities to Provide for Absorption of Output of Shasta Power Plant in Northern California Market, 1938. The Story of the Central Valley Project of California, 1940. ♦Electric Power Features of the State W^ater Plan in the Great Central Valley Basin of California, 1941. Auxiliary Electric Power Facilities Required for Central Valley Project, 1942. ♦ Reports and Bulletins out of print. These may be borrowed by your local library from the California State Library at Sacramento, California. O 71061 3-47 2700 THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW MAR 1 '65 BOOKS REQUESTED BY ANOTHER BORROWER ARE SUBJECT TO IMMEDIATE RECALL Becewtu otcs \9SC 11 LIBRARY, UNIVERSITY OF CALIFORNIA, DAVIS Book Slip— Series 458 wateiL^:espurce^ PHYSICAL SCIENCES LIBRARY 75 01001 9555 ^^.»i.-« DAVIS 111613