WATER RESOURCES SUMMARY FOR 

SOUTHERN CALIFORNIA, 1957 
, 
UNITED STATES DEPARTMENT OF THE INTERIOR 

FRED A. SEATON, Secretary 

GEOLOGICAL SURVEY 

Thomas B. Nolan, Director 

GEOLOGICAL SURVEY CIRCULAR 404 

WATER RESOURCES SUMMARY FOR 

SOUTHERN CALIFORNIA, 1957 

By William C. Peterson 

Washmgton, D. C. 1958 

Free on application to the Geological Surtey, Washington 25, D. C. 

CONTENTS 

Page 

Abstract..................................................... 1 

Introduction................................................. 1 

Water resources for the water year 1956-57 ...... 3 

Precipitation...................... . . . . . . . . . . . . . . . . . . . . .. 3 

Runoff.................................................... 3 

Annual runoff for the water year 1956-57 .... 5 

Current dry period............ . . .. .. .. .. .. .. .. .. .. 8 

Surface storage......................................... 8 

Ground water............................................ 9 

Western San Diego County........................ 9 

Riverside County.................................... 11 

San Bernardino Valley............................. 11 

Page 

Water resources for the water year 1956-57-Con. 

Ground water-Con. 

San Gabriel Valley.................................... 11 

Coastal plain........................................... 11 

Oxnard plain............................................ 12 

Santa Maria Valley.................................. 12 

Antelope Valley........................................ 12 

Artificial recharge of ground water............. 12 

Imported water........................................... 12 

Annual runoff for the water year 1955-56............ 13 

Areal distribution....................................... 13 

Unit runoff. . . . . . . . . . ........... ·. . . . . . . .. . . . . . . . . . . . . . . . . . . 19" 

ILLUSTRATIONS 

Figure 1. 

2. 

3. 

4. 

5. 

6. 

7. 

Page 

Location of selected gaging stations and observation wells........................................................ 2 

Progressive 10-year mean annual precipitation....................................................................... 4 

Annual runoff distribution, 1896-1957 •.. ~ ........................................................................... ~.... 6 

Mean annual runoff for different periods, 1896-1954........................................... .................... 7 

Water-level fluctuations at selected obs-ervation wells.............................................................. 10 

Water imported into southern California ............................................................................... . 13 

Areal distribution of annual runoff for the water year 1955-56 ................................................... . 18 

TABLES 

Page 

Table 1. Annual precipitation............................................................................................................ 5 

2. Annual runoff for the water year 1956-57 and the average annual runoff for 

the dry period 1944-57 at selected gaging stations...................................................... .. ........ 8 

3. Storage in selected surface reservoirs.................................................................................... 9 

4. Annual runoff for the water year 1955-56.... ... ............... ....................................... ....... ............. 14 

III 

WATER RESOURCES SUMMARY FOR SOUTHERN CALIFORNIA 

1957 

By William C. Peterson 

ABSTRACT 

Current water requirements for southern California 

are more than 2 million acre-feet per year. These 

requirements are being satisfied by supplementing 

limited local water reserves with imported water. 

The average annual precipitation ranges from about 

2 inches in parts of the desert to about 50 inches in the 

higher mountains. Also, there is a great variation in 

annual precipitation at any one place, 

The annual variation is not entirely random in that 

the annual precipitation tends to occur in sequences of 

wet and dry years. Records of the 1956-57 climatol~gical year indicate that the dry period which began in 

1944 continues unabated. 

Runoff follows the same cyclic pattern of wet and dry 

periods established by precipitatiqn, but with even 

greater variability. Annual i·unoff for the 1956-57 

water year at 15 selected gaging stations ranged from 

0, 0 to 5, 0 inches with departures from the average 

annual runoff for the 35-year base·-mean period, 1920-

55, ranging from minus 100 to minus 52 percent. The 

average annual runoff for the 1956-57 water year was 

1. 41 inches, a departure of minus 65 percent from the 

base mean. The average annual runoff for the 13-·year 

dry period 1944-57 ranged from 0, 24 to 6, 9 inches 

with an average departure of minus 44 percent. 

As result of these continuing dry years, most of the 

reservoirs storing natural runoff were practically dry. 

The combined contents of 12 selected reservoirs in 

September 1957 was only 7. 5 percent of total capacity. 

The trend in ground-water depletion that began in 

1944 continued during the year. Although the increased 

use of imported water for recharge of ground-water 

basins reduced the rate of decline in some areas, water 

levels in most observation wells were the lowest of the 

period of record. In areas entirely dependent on local 

ground-water reserves for their supply, the problem 

of obtaining sufficient water became more critical. 

The rapid increase in requirements of water stepped 

up the importation of water from the Colorado River 

from 20, 000 acre-feet in 1944 to 597, 000 acre-feet in 

1957. During the same period, importations from 

Owens Valley were running close to aqueduct capacity; 

331,000 acre-feet was imported from this source 

during 1957. 

Annual runoff data for the 1955-56 water year from 

all currently published gaging-station records establish 

that year as one of the driest in recent years in southern California, 

INTRODUCTION 

This water-resources summary is the 15th in a 

series issued annually since June 1944. Its main 

purpose is to present a brief analysis of those phases 

of local water supply associated with the work of the 

Geological Survey in southern California, 

The first part of this summary deals with water 

resources for the water year ending September 30, 

1957. It contains a brief analysis of annual precipitation, annual runoff (provisional) at selected gaging 

stations, water reserves in both surface and underground reservoirs, and supplemental imported water. 

The second part of this summary gives, in detail, 

annual runoff for the preceding water year ending 

September 30, 1956. A period of about 1 year, beginning at the end of the water year, is usually required 

to complete computations of daily discharge for all 

the gaging stations. An additional 6 months to a year 

is required to process and present the data in published form in the annual Geological Survey water-supply 

papers. Consequently, this summary represents the 

first opportunity to release data on magnitude of runoff 

for all stations now operated in southern California for 

the water year 1955-56, 

Some of the information presented in this summary 

was included in previo-qs issues. The repetition is 

made so that each summary will be complete and 

entirely independent of previous issues, 

For the purpose of this summary, southern California is that part of the State extending southward along 

the coast from the Arroyo Grande basin to the international boundary and inland to include all the area to 

the Colorado River and Nevada State line south of the 

Tehachapi Mountains and Inyo County. The inland part 

of this 47, 000-square-mile area is predominantly an 

arid desert. Consequently most of the population 

centers and agricultural areas of the region are concentrated in the long narrow band of coastal land. The 

chief exceptions are Antelope Valley in the Mojave 

Deser.t and Coachella and Imperial Valleys in the Colorado Desert. The area covered in this summary is 

shown in figure 1. 

Because of many desirable climatic and economic 

factors, the population growth of southern California 

has been phenomenal, probably the greatest in the 

Nation. A population of about 300, 000 in 1900 increased to about 5. 7 million by 1950. About 80 percent of 

this population increase occurred in the three decades 

since 1920. Since 1950 the population growth has 

continued, and it is estimated that the present population of southern California is about 8 million. 
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WATER RESOURCES FOR THE WATER YEAR 1956-57 3 

Such a vast increase in population greately intensifies the water problems in these arid and semiarid 

regions of limited water reserves. It has been estimated that the water requirements for urban and agricultural purposes in the coastal areas were about 

1.8 million acre-feet in 1950 and have been steadily increasing at a rate of about 40, 000 acre-feet per year. 

As a result, the water situation has changed from good 

to extremely critical in many areas. Just how critical 

the situation is depends largely upon the magnitude of 

the local ground-water reserves and the ability of the 

community to import water from outside the basin. 

Southern California has been forced to obtain its water 

supply from distant ·sources because of its limited local 

water reserves; as a result this area pays more for its 

water than any other area of comparable size in the Nation. 

WATER RESOURCES FOR THE WATER YEAR 1956-57 

Precipitation 

Very few areas in the United States experience 

ranges in average annual precipitation that are as wide 

as those observed in southern California. Because of 

modifications in the atmospheric-moisture circulation 

by local physiographic features, the observed average 

annual precipitation ranges from 2. 24 inches at Bagdad 

in the Mojave Desert to 51. 53 inches at Morse near 

Squirrel Inn in the San Bernardino Mountains. 

On an areal basis the average annual precipitation of 

southern California is about 9. 5 inches, or only about 

32 percent of the national average of 30 inches. Not 

more than 2 percent of southern California has an 

average annual precipitation equal to or larger than 

that of the United States. More than 50 percent of 

southern California is arid, with an average annual 

precipitation of 5 inches or less. 

In addition to the great range in average annual precipitation from place to place, there is often an even 

greater variation in annual precipitations at any one 

locality. For instance, the annual precipitation at 

Los Angeles for the climatological year, July 1 to 

June 30, has ranged from 5. 59 inches in 1898-99 to 

38. 18 inches in 1883--84, and averaged 14. 99 inches 

for a 80-year period of record ending in 1957. At 

Indio, in the desert area of southern California, the 

annual precipitation has ranged from 0. 40 inch in 

1B79-80 to 11. 50 inches_ in 1939-40, and averaged 

3. 16 inches for a 79-year period of record ending 

in 1957. 

The variation in annual precipitation is not entirely 

random as the annual preCipitation occurs in sequences 

of wet and dry years. The sequences represent a time 

distribution in which the wet years predominate, alternating with other periods in which dry years predominate-resulting in an irregular cyclic pattern. This 

distribution in time is most pronounced on the coastal 

side of the mountains and least defined in the arid 

desert reg~ons. 

Possibly the longest existing record of these wet and 

dry sequences is to be found in the growth of annual 

tree rings in certain types of trees gi'owing in the 

mountains of southern California. Schulman 1 has 

been able to measure the annual tree-ring growth in 

big-cone spruce for the 560-year period of 1385 to 

1944. These records indicate a definite cyclic pattern, 

with the average length of dry periods amounting to 

14. 5 years and wet periods amounting to 12. 5 years, 

giving an average cyclic period of 27 years. Not all 

the individual years within a wet period are wet, but 

the wet years predominate; likewise, not all the individual years within a dry period are dry, but the dry 

years predominate. 

A diagram showing the progressive 10-year means 

(fig. 2) is frequen,tly used to show the existence o{ 

the alternating wet and dry periods. Points used 

to define these three curves represent the departures of the 10-year mean annual precipitation from 

the average annual precipitation for the period of 

record at Los Angeles, Santa Barbara, and San 

Diego for successive 10-year periods. The three 

pronounced highs in this diagram represent wet 

periods; the lows repr_esent dry periods. Final 

points for the last 10-year period of these curves 

represent the mean annual precipitation from July 1, 

1947, to June 30, 1957. 

The observed 1957 annual (climatological year, 

July 1 to June 30) precipitation at these three typical 

southern California stations is given in table 1. During 

this year, the 13th year of a predominately dry period, 

the annual precipitation at all three stations was less 

than the average for the period of record; in fact, 

during the 10-year period 1948-57 there was only 

1 year with above-average precipitation at each location. The influence of the 1957 precipitation is such 

as to reverse the trends at San Diego and Los Angeles 

and to continue the upward trend at Santa Barbara. 

(See fig. 2.) 

Runoff 

The precipitation, after first satisfying the soilmoisture deficiencies in the root zone of the native 

vegetation in mountain and foothill areas and of the 

agricultural crops in the valley-floor areas, recharges 

the ground-water reservoirs or drains into the stream 

channels as runoff. That part of the precipitation 

appearing as runoff follows the same cyclic tenden<;:y 

shown in figure 2. However, this cyclic tendency is 

often more pronounced because the annual runoff may 

represent only a very small part of annual basinwide 

precipitation. For example, the annual runoff for San 

Gabriel River near Azusa has ranged from as little as 

0. 86 inch throughout the basin for the water year ending September 30, 1899 to a maximum of 36·. 4 inches 

for the water year ending September 30, 1922, with an 

average of 9. 7 inches for a 62-year period of record. 

This range in annual runoff, together with its time 

sequence, is shown in figure 3 for the gaging station 

on San Gabriel River near Azusa and the gaging station 

on Santa Ana River near Mentone. Both stations reflect the runoff from rugged mountain basins within 

the San Bernardino and the Angeles National Forests 

where efforts are made to protect and maintain a 

native vegetative cover. The records for these two 

1schulman, Edmund, 1947, Tree-ring hydrology 

in southern California: Univ. Ariz. , Lab. of Treering Research, Bull. 4. 
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WATER RESOURCES FOR THE WATER YEAR 1956-57 5 

Table 1. -Annual precipitation 

Period of record 

Station 

Length Average annual 

(years) precipitation 

(inches) 

San Diego. ....•......•................ 107 9.94 

Los Angeles ......................... 80 14.99 

San Barbara ......................... 90 17.91 

stations are assumed to be typical of the mountain runoff in those areas where the basinwide average annual 

precipitation ranges from 30 to 40 inches. Both records display the same cyclic tendencies shown by the 

annual precipitation. To accentuate this distribution, 

the records have been segregated into the generally 

accepted wet and dry periods of the region, with the 

average annual runoff for each of these periods shown 

by the crosshatched area. 

One of the methods used for determining wet and dry 

periods is that of cumulative departures as shown in figure 4. The diagrams show cumulative departures-of annual runoff from the mean annual runoff, in percent, from 

1895 to 1954 for San Gabriel River near Azusa and from 

1896 to 1954 for Santa Ana River near Mentone. A continuously downward trend represents a dry period; a 

continuously upward trend represents a wet period. 

It is evident from an inspection of figure 4 that both 

records contain 3 dry and 2 wet periods and consequen_tly the means for the periods of record tend to be 

biased because of the greater number of dry years. 

On the basis of the records for San Gabriel River near 

Azusa, the 49-year period of 1896-1944 and the 50-

y.ear period of 1905-54 represent the least biased records because each contains 2 wet and 2 dry periods. 

For Santa Ana River near Mentone, the least biased 

records are those for the 47-year period 1897-1943 

and for the 49-year period 1906-54. As there are but 

a few gaging stations in southern California where records are of sufficient length to contain these optimum 

time periods, it is necessary to consider the use of 

shorter periods, each containing a single wet and dry 

sequence. The beginning and the ending of each of 

these periods, together with the mean annual runoff 

for each period, are included in figure 4. 

The obvious variability of the short-period data 

suggests that it is doubtful that the longtime mean can 

be used as a direct measure of dependable runoff for 

any randomly selected period. Consequently the longtime mean annual runoff becomes merely an indirect 

measure of the relative runoff among basins rather 

than a measure of usable or available water during 

extended critical periods. 

Despite the shortcomings of the longtime mean in 

reference to most of southern California's water 

problems, the use of mean values as a measure of 

central tendency is desirable for brevity. Furthermore, mean values based on a common time period 

are more suitable for the purpose of the water resources summary than longtime means based on 

periods of varying length. Admittedly, any selected 

· 10-year period 

1957 annual precipitation 1948-57 mean annual 

precipitation 

Departure Departure 

Inches from average Inches from average 

(percent) (percent) 

8.89 -10.6 8.62 -13. 3 

9. 54 -36.4 11. 92 -20. 5 

13.86 -22.6 15. 53 -13.3 

time period will be arbitrary because of areal differences in the beginning and ending dates of the sequences of wet and dry groups of years and lack of 

definition of the sequences in drainage areas of meager 

precipitation. But base means developed from a 

common time period are more directly comparable 

between basins that are longtime means developed 

from different length periods and, when properly interpreted, have considerable significance in many parts 

of southern California. 

For the water resources summary, the 30-year 

period beginning October 1920 and ending September 

1950 was initially selected for a base mean, and was 

used in recent editions of the summary. October 1920 

was chosen as the beginning date so that the base period 

would conform closely to that of the standard period 

October 1920 to September 1945 for which median 

monthly discharge is computed and used for national 

coverage in the Water Resources Review of the U. S. 

Geological Survey and the Canadian Water Resources 

Division. The choice of this beginning date also enabled the inclusion, in the base-mean period, of many 

shorter runoff records that could be extended back to 

October 1920 with a minimum loss of accuracy. 

Beginning with this edition of the summary, the 

35-year period from October 1920 to September 1955 

is used for computing base means. It is contemplated 

that the 35-year period will be used through the 1961 

edition of the summary. 'The base means for the 

35-year period are a few percent lower than those for 

the 30-year period, which should be borne in mind 

when comparing percentage departures in this edition 

of the summary with those in Circular 399 and 

earlier editions. 

Annual runoff for the water year 1956-57 

Annual runoff for the water year 1956-57 at the 15 

gaging stations shown on figure 1 is briefly summarized in table 2 and compared to the average-annual 

runoff for the 35-year base period of 1920-55. 

The intent of table 2 is to provide a general index of 

the surface runoff throughout southern California for 

the water year ending September 30, 1957. The wide 

range of the 1956-57 runoff, 0. 0 to 5. 0 inches, is 

typical of the region and is due largely to the areal 

distribution of precipitation. Departures of the 

1956-57 runoff from the 35-year base means we~e 

about the same as those of the preceding 1955-56 

water year, with the exception of the Huasna River in 

the San~a Maria basin and Arroyo Grande in the Arroyo 
San Gabriel River near Azusa, Calif. 

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Mean==----

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Figure 3. -Annual runoff distribution, 1896-1957. 

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WATER RESOURCES FOR THE WATER YEAR 1956-57 

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WATER YEARS 

Figure 4. -Mean annual runoff for different periods, 1896-1954. 

7 

1950 1960 
8 WATER RESOURCES SUMMARY FOR SOUTHERN CALIFORNIA, 1957 

Table 2.--Annual runoff for ~he water year 1956-57, and the average annual runoff for the dry period 

1944-57 at selected gaging stations 

Locali ty Drain- 1920-55 no. age base mean on Station area annual 

fig. (square runoff 

1 miles) (acrefeet) 

Pacific Slo2e Basins: 

799 Cottonwood Creek at Morena Dam 120 11,250 304 Santa Ysabel Creek at Sutherland Dam------------- 58 12,340 

721 Murrieta Creek at Temecula---- 220 9,380 102 Santa Ana River near Mentone-- 202 55,680 

616 Cucamonga Creek near Upland--- 10.1 5,710 

765 East Fork San Gabriel River near Camp Bonita----------- 88.2 48,910 4 Arroyo Seco near Pasadena----- 16.4 6,270 

377 Santa Anita Creek near Sierra 

Madre---------------------- 10.5 4,360 182 Sespe Creek near Fillmore----- 254 70,980 845 San Jose Creek near Goleta---- 5.54 -- 638 Huasna River near Santa Maria- 119 12,540 821 Arroyo Grande at Arroyo Grande 106 14,940 

The Great Basin: 

647 Palm Canyon Creek near Palm 

Springs-------------------- 94.0 4,390 666 Deep Creek near Hesperia------ 137 44,271 499 Big Rock Creek near Valyermo-- 23.0 12,100 

Grande basin. Runoff in these excepted basins at the 

extreme northern end of. coastal southern California 

decreased a small percent of the base mean to magnitudes roughly comparable to those of the 1954-55 

water year. 

The average annual runoff for the 1956-57 water 

year was 1. :t 1 inches over the 1, 464 square miles of 

mountain drainage listed in table 2, or about 35 percent of the 35-year base runoff. During the 1955-56 

water year the average annual runoff for this group of 

basins was 1. 77 inches, or about 1. 25 times that of 

1956-57. 

Current dry period 

The typical southern California runoff distribution 

shown on figure 3 indicates that the water year ending 

September 30, 1957 was among the driest during the. 

observational period. Furthermore, this dry year 

was the 13th in a predominately dry period that has 

persisted since October 1944-and may not end for 

some time. The tree-growth studies by Schulman 

suggest that southern California may have experienced 

dry periods of more than 40 years. 

A measure of the relative dryness of the dry periods 

is afforded by numbering the 10 driest years, fur each 

of the stations shown in figure 3, in their order of dryness. Of these 20 years at both stations, 9 occurred 

in the very dry 9 -year period ending September 30, 

1904. The current dry period is next in order with 8 

years, and the 14-year period ending September 30, 

1936 was the least dry,· containing only 3 of the 

20 years. 

The average runoff for the current dry period and 

its relation to the base mean is included in table 2. 

Average annual runoff 

1956-57 runoff for 1944-57 dry period 

Departure Departure 

from from 

Acre- Inches base mean Acre- Inches base mean feet annual feet annual 

runoff runoff 

(percent) (percent) 

263 0.04 -98 2,970 0.46 -74 

940 .30 -92 4,410 1.4 -64 

997 .08 -89 3,390 .29 -64 

26,400 2.5 -53 36,910 3.4 -34 

1,840 3.4 -68 3,730 6.9 -35 

23' 630 5.0 -52 31,390 6.7 -36 

1,150 1.3 -82 3,220 3.7 -49 

1,570 2.8 -64 2,580 4.6 -41 

23,540 1.7 -67 36,710 2.7 -48 

784 2.7 -- 836 2.8 -- 681 .11 -95 6,130 .97 -51 

3,320 .59 -78 8,700 1.5 -42 

9.2 0 -100 1,260 .24 -71 

20,450 2.8 -54 26,000 3.6 -41 

4,420 3.6 -63 7,620 6.2 -37 

At most of the stations the average runoff for the 

period 1944-57 was less than that for the period 

1944-56. The average departure of the runoff from 

the 35 -year base mean during the 13 -year dry period 

for the basins listed was minus 44 percent. 

Surface storage 

Currently there exists about 1. 5 million acre-feet 

of surface storage in southern California for municipal, domestic, and irrigational uses. Most of this 

storage has been obtained by building dams across 

mountain stream channels. However, because of the 

many adverse topographic features, such as steepness 

of the stream channels and narrowness of the canyons, 

construction costs are high and reservoir capacities 

small. Only 5 reservoirs of 115 built have a capacity 

in excess of 100, 000 acre-feet. Because of these 

relatively small reservoir capacities, it is impossible 

in many instances to carry over the excessive flood 

runoff occurring during wet periods for use in the 

following dry periods. Furthermore, some of these 

reservoirs were not built for the purpose of storing 

local flood runoff but were intended for the storing and 

distribution of imported waters from Owens Valley and 

the Colorado River. 

Because of the necessity for flood control in the 

valley-floor areas, additional storage of more than 

400, 000 acre-feet has been developed. Even though 

these flood- control reservoirs are primarily for 

retarding the flood runoff, a certain amount of water 

conservation is accomplished because provision is 

made, when possible, to control releases for efficient 

recharge of ground-water basins. 

Data regarding the behavior of 12 reservoirs during 

the current dry period are given in table 3. These 
WATER RESOURCES FOR THE WATER YEAR 1956-57 9 

Table 3 --Storage in selected surface reservoirs 

Average Present Storage Storage on 

annual capacity Storage Sept. 30 1956 Sept. 30 1957 Change Sept. 30, 1944 Change in 

Reservoir 1920-55 at spill- ratio Percent Percent in ·percent storage 

inflow way level (years) Acre-feet of Acre-feet of storage Acre-feet of 1944-57 

(acre-feet) (acre-feet) capacity capacity (acre-feet) capacity (acre-feet) ------·--

Morena and Barrett----- 24,800 94,970 3.8 1,410 1.5 1,270 1.3 -140 89,900 86 -88,630 El Capitan---- 38,600 112,810 2.9 6,690 5.9 2,540 2.2 -4.,150 79,700 68 -77,160 Lake Hodges--- 33,280 33,550 1.0 a2,640 7.9 a3,460 10 +820 31,100 93 -27,640 Lake Henshaw-- 24,410 194,300 8.0 bl,800 1.0 bl,080 .6 -720 144,000 74 -142,300 

Vail Lake----- 9,810 49,370 5.0 810 1.6 560 1.1 -250 -- -- -- Big Bear Lake- -- 72,200 -- 2,830 3.9 1,950 2.7 -880 47,600 66 -45,650 

Santiago------ 11,220 25,000 2.2 2,830 11 3,700 15 +870 20,400 82 -16,700 

Matilija------ 20,910 7,020 .34 5,560 79 5,250 75 -310 -- -- -- Jameson Lake-- 3,840 6,760 1.8 3,030 45 bl,260 19 -1 '770 6,050 89 -4,790 

Gibraltar----- 30,540 14,780 .48 11' 660 79 10,340 70 -1,320 6,120 38 +4,220 

Cachuma-- - - 60' 700 210,000 3.5 36,600 17 30,150 14 -6,450 -- -- -- Total c268,000 820,760 3.1 75,860 9.2 61,560 7.5 -14,300 424,870 78 -398,650 

aMostly Colorado River water. bApproximately. c Includes estimate for Big Bear Lake. 

reservoirs were built for the purpose of supplying 

domestic, municipal, or irrigational water. Except 

for Lake Hodges, the only source of inflow to each 

reservoir during 1957 was from local runoff. The 

combined capacity of these 12 reservoirs is about 55 

percent of their total capacities thus far developed for 

. the purposes they were built. 

The Morena and Barrett Reservoirs in the Tia Juana 

River basin are the most southerly of this group. At the 

end of the preceding dry year-on September 30, 1956-

these reservoirs were almost empty. At the end of the 

equally dry 1957 water year the reservoirs were still 

almost empty. This is typical of the larger reservoirs 

where the average annual inflow is small in comparison with storage capacity and where· the holdover storage from the preceding wet period has long -been exhausted. Farther north, however, at the Matilija Reserv:oir1 the storage at the end of the 1956 water year 

amounted to 79 percent of capacity, and at the end of 

the 1957 water year amounted to 75 percent of capacity. 

This relatively large retention is typical of those reservoirs in which the average annual inflow is large in 

terms of the reservoir's capacity. 

Column 4 of table 3 gives storage ratio, which is defined as the ratio of usable capacity to average annual 

runoff. It is expressed in years and is the time required, assuming average runoff, to impound a volume of 

water equal to the usable capacity of the reservoir. 

Ground water 

Over a large part of southern California, the most 

readily available and best distributed water reserve is 

the water stored in the deep alluvial deposits of the 

valley-floor area. A major part of the water requirements of the region has been and is being supplied by 

pumping from this source. The magnitude of these 

water reserves is difficult to :measure; however, they 

have been estimated by Eckis2' to be about 7. 5 million 

acre-feet in the alluvial deposits in the basins of the 

Los Angeles, San Gabriel, and Santa Ana Rivers in a 

zone 100 feet thick extending from 50 feet above to 

50 feet below the January 1933 water levels. 

The rapid growth of the industrial and urban developments has overtaxed these reserves. As a 

2Eckis, Rollin, 1934, Geology and ground-water 

storage capacity of valley fill (South Coastal Basin 

Investigation): California Dept. Public Works, Div. 

Water Resources, Bull. 45. 

consequence the current rate of extraction often 

exceeds the average rate of recharge, creating an 

overdraft. Currently, many ground-water basins in 

southern California now have, or are threatened by, 

overdrafts. 

The usefulness of a ground-water reservoir, like a 

surface-water reservoir, is dependent upon its size, 

the magnitude of the annual increments of recharge, 

and the annual rate of withdrawal. Also, like a surface reservoir, the ground-water reservoir must 

capture its water in the wet periods and retain it in 

storage to meet the needs of the following dry periods. 

The valleys of southern California contain a large 

number of ground-water basins, many of which have 

complex geologic and hydrologic features. Changes 

in water levels differ considerably from basin to basin, 

depending upon the relationship between natural recharge and pumping draft. Consequently it has been 

necessary to confine the detailed analysis of the 

changes in water levels to the few observation wells 

indicated on figure 1. 

The records of change in water level in six selected 

observation wells for their period of record are 

shown on figure 5. The division of wet and dry periods 

is based arbitrarily on figure 4. A light dashed line 

indicates the rate of decline during each dry period 

and is based chiefly on the group of years having the 

least precipitation during the period. Assuming that 

ground-water recharge during all dry periods is 

small and of about the same magnitude, an increase 

in the rate of decline becomes a measure of the increase in ground-water extractions. 

At the end of the 1957 water year, almost all water 

levels were the lowest for the period of record-a 

reflection of the great increase in regional water 

requirements and the excess of withdrawals over the 

small increments of recharge during the current 

13-year dry period. 

Western San Diego County 

Ground-water levels in the coastal alluvial valleys 

of western San Diego County, including the basins of 

the Tia Juana, Otay, Sweetwater, San Diego, San 

Dieguito, and San Luis Rey Rivers, declined during 

the 1957 water year, continuing a downward trend 

which began about 13 years ago. By September 30, 
10 WATER RESOURCES SUMMARY FOR SOUTHERN CALIFORNIA, 1957 

80---t----

2340 

2320 

~--Dry-+--~---+- Wet Dry 

2280 

2260 

2240 

2220 

Figure 5. -Water-level fluctuations at selected observation wells. 
WATER RESOURCES FOR THE WATER YEAR 1956-57 11 

1957, the levels in many wells were the lowest of 

the entire period of record. Near the coast in the San 

Luis Rey and Otay River basins, the water levels were 

below sea leve 1 during all or part of the year. At the 

present time, areas of known or threatened sea-water 

intrusion exist in the basins of the Tia Juana, Otay, 

San Diego, and San Luis Rey Rivers. 

Riverside County 

The ground-water levels in the arid and semiarid 

San Jacinto basin have declined steadily since the first 

observations of 1904. The Riverside County Flood 

Control and Water Conservation District reports that 

the water level in the observation well 4S/ 1 W-35RI, 

near the city of San Jacinto, was about 200 feet below 

land surface in September 1957; this well was flowing 

in 1917. Similarly the water level in a second well 

4S/ 3W-33RI, near the city of Perris, was about 186 

feet below the land surface during September 1957 in 

an area where the water level was about 20 feet below 

the land surface during March 1904. Both areas now 

are using a limited amount of Colorado River waterat double the cost of locally pumped water-in an effort 

to supplement .the declining water reserves. 

At the end of the 1957 water year, ground-water 

levels in certain areas of the Riverside and Whitewater 

basins were about 7 feet below those observed during 

the fall of 1956; and at the Wildomar School in the 

Murrieta- Temecula basins, the ground-water level 

declined almost 14 feet during the year. A reversal of 

the general downward trend was observed in the 

Elsinore basin where ground-water levels rose 2-10 

feet. The rise was- generally attributed to the importation of Colorado River water to the valley area of the 

basin. 

San Bernardino Valley 

The San Bernardino Valley is a ·relatively deep 

alluvial valley in the upper Santa Ana River basin east 

of metropolitan Los Angeles. The water needs of the 

valley's prominent agricultural and urban developments 

are supplied from local surface and ground-water 

sources. 

The longest available record of changes in groundwater levels is that for the Williams well 

(1S/3W-17C1). This record (fig. 5) began in 1892 and 

indicates the response to seasonal changes caused by 

pumping and recharge and to the long-term changes 

associated with wet and dry periods tending to give 

the water-level fluctuation a general cyclic time 

distribution that coincides closely with the wet and dry 

periods shown on figure 4. 

The rate of decline during the first and second dry 

periods amounted to about 4. 2 feet per year. However, 

during the current dry period the rate of decline increased to about 10 feet per year. This increase in 

rate of declil).e reflects an increase in ground-water 

use that, when contrasted with the average rate and 

duration of recharge during wet periods of record, 

forecasts a condition of overdraft in the near future. 

The San Bernardino Valley Water Conservation 

District reports that the valley's ground-water levels 

at the end of the 1957 water year averaged about 110 

feet below the levels at the beginning of the current 

dry period. Owing to the increasing export of water 

from the area above the San Jacinto fault, many wells 

have either gone dry or the yields have diminished to 

the point where the wells have become unusable. 

Among these was the Williams well, which went dry in 

July 1956 and was still dry in January 1957. Waterlevel records obtained since March 1957 are from a 

companion well (1S/ 3W -1 7C2) drilled to replace the 

Williams well. Deepening of wells, lowering of 

pumps, and increased pumping costs are imposing 

serious economic hardships on water users, particularly those in the fringe areas of the valley. 

San Gabriel Valley 

The San Gabriel Valley is a deep alluvial valley in 

the San Gabriel River basin along the toe of the San 

Gabriel Mountains. The ground-water-storage capacity of these deposits is believed to be about 1.2 million 

acre-feet in a zone 100 feet thick, ranging from 50 

feet ab<;we to 50 feet below the January 1933 water 

level. 2 The once extensive agricultural acreage in 

this valley is rapidly being converted into an urban 

area .. Most of the valley's water requirements are 

met from local ground-water reserves. 

The record obtained at the Baldwin Park observation 

well 1S/ 10-18 (fig. 5) is assumed to represent groundwater conditions throughout the valley. During the 

dry period 1922-36, the average rate of water-level. 

decline was about 3.9 feet per year and increased to 8.8 

feet per year during the current dry period. During 

the last few years, this rate of decline has moderated, 

owing partly to the wet year 1951-52 and partly to the 

increased use of imported Colorado River water in 

the area. 

Coastal plain 

The coastal plain is the broad, flat area extending 

along the coast from Santa Monica to Newport Beach 

and inland to the Santa Monica and Santa Ana Mountains, the Puente and San Jose Hills, and lesser foothills. Three major streams-the Santa Ana, San 

Gabriel, and Los Angeles Rivers--cross this plain to 

discharge into the ocean. The rich agricultural lands 

of the plain have been converted gradually into extensive urban and suburban areas. Currently, the coastal plain is the most densely populated and industrialized section of southern California. 

The fresh-water-bearing deposits underlying the 

plain are composed of marine and alluvial material 

that locally attain a thickness of 2, 500 feet or more. 

Less than 20 years ago the water stored in these 

deposits was the principal source of water for the 

area. Because of the rapid increase in water needs 

during recent years, it has been necessary to import 

a substantial part of the water requirements from 

Owens Valle..Y and the Colorado River. Even with 

these imported waters, the ground-water reserves 

have been so depleted that sea water has intruded 

these deposits along many sections of the coast. 

2see footnote p. 9. 
12 WATER RESOURCES SUMMARY FOR SOUTHERN CALIFORNIA, 1957 

Systematic observations of change in ground-water 

level in the coastal plain have been noted at the Neff 

well 4S/ 10-22L2 and its companion wells near Anaheim 

since 1898. These records (fig. 5) have been used as an 

index of changes in the water level of the coastal plain. 

During the 59-year period of record at this site, a net 

decline of 132 feet (from 112 feet above sea level to 

20 feet below sea level) was observed. This decline, 

which has not been uniform, was concentrated largely 

in the three dry periods. An average rate of decline 

of 3. 9 feet per year in the first dry period increased 

to 4. 6 feet per year during the second dry period and 

to 7. 6 feet per year in the current dry period. During 

the last few years, this rate of decline has moderated 

owing partly to the wet year 1951-52 and partly to 

greater use of imported waters. 

The Orange County Water District reports an average rise in ground-water level of 15. 5 feet throughout 

the eastern part of the coastal plain during 1957. This 

level is about 5. 5 feet higher than the average level 

at the end of the 1956 water year and reflects the 

spreading of 102, 000 acre-feet of Colorado River 

water to replenish the underground basin. In addition 

to the water purchased by the Orange County Water 

District, about 46, 000 acre-feet of Colorado River 

water was purchased by cities and other water users 

for direct use in areas previously supplied from the 

district basin. 

Oxnard plain 

The Oxnard plain is one of the most important 

agricultural and urban areas in Ventura County. Waterlevel observations made by Ventura County Water 

Resources Division, at well 9- U-9 in the city of Oxnard 

(fig. 5) ar~ assumed to represent changes in the 

ground-water reserves beneath this broad coastal 

plain. Since 1943 the water level at this site has declined almost continuously. Between 1943 and 1951 the 

average rate of decline was about 7. 4 feet per year. 

This trend was reversed temporarily by recharge in 

the wet year 1951-52. However, since 1953 the decline in water level has resumed at a rate somewhat 

less than that before 1952. 

The Ventura County Water Resources Division reports that the ground-water levels of the Oxnard plain 

were generally about 25 feet below sea level in the fall 

of 1957. At this same time the water levels were about 

63 feet below sea level in Pleasant Valley, an eastward extension of the Oxnard plain. There is evidence 

of sea-water intrusion in wells near the ocean. 

Santa Maria Valley 

Changes in water level in well 10/34-14E2 (fig. 5). 

near the center of the Santa Maria Valley, genera'iiy 

reflect the status of ground water in storage for a 

large part of the valley. The records from this well 

show a continuous and almost uniform decline in water 

level at a rate of 4. 0 feet per year during the dry years 

1917-36. As a result _of the large ground-water recharge during the w~t period extending through 1944, 

the water level in this well rose about 35 feet. During 

the current dry period, the water level declined at an 

average rate of 7. 4 feet per year to the lowest level 

on record, indicating a substantial increased draft on 

the ground-water reserves. 

Antelope Valley 

Antelope Valley is in the extreme west end of the 

Mojave Desert in Los Angeles and Kern Counties. Parts 

of this arid valley have been farmed successfully for 

more than 60 years. However, the steadily increasing water needs for agricultural and other uses have 

created a critical overdraft in the valley. 

Figure 5 shows the changes in water level in a well 

near Lancaster; they are assumed to be an index of 

changes in the large, heavily pumped part of the 

valley. During the last 26-year period the water level 

in this and nearby wells has declined about 145 feet. 

This decline, which persisted even during the wet 

years, clearly indicates that extractions exceeded the 

recharge. A rate of decline of about 3. 4 feet per 

year during the 1922-36 dry period has increased to 

8. 1 feet per year during the current dry period. 

Artificial recharge of ground water 

The Metropolitan Water District of Southern California reported that it sold about 152, 000 acre-feet of 

Colorado River water at a cost of more than $1. 5 

million to the people of Los Angeles and Orange 

Counties during the 1957 water year for the major 

purpose of retarding the rapid rate of decline in 

ground-water levels. This water was permitted either 

to infiltrate into the stream-channel deposits or 

to spread into highly permeable specially prepared 

basins overlying. the main ground-water bodies. 

About 3, 500 acre-feet of Colorado River water was 

put into injection wells along the coast in the vicinity 

of Manhattan Beach to maintain a fresh-water barrier 

against sea-water intrusion. 

An additional 9, 000 acre-feet of local storm runoff 

from the mountain and foothill areas during the 1957 

water year was diverted from natural stream channels 

into specially prepared basins for the purpose of recharging the ground-water reservoirs in Los Angeles 

County. 

Imported water 

Southern California extends over a predominately 

arid region which has less than 2 percent of the State's 

natural water supplies. Consequently, to satisfy the 

ever-increasing water requirements of the area, water 

must be imported from distant sources. 

Since 1913 the city of Los Angeles has diverted water 

from the Owens Valley east of the Sierra Nevada for 

use in the city some 250 miles to the south. During 

the 1957 water year the Owens River aqueduct, operating at full capacity as in previous years, delivered 

331,000 acre-feet to the Los Angeles area. 

By means of a 1, 617-foot pumping lift and a 242-

mile aqueduct from the Colorado River, the Metropolitan Water District of Southern California delivered 

597, 000 acre-feet to the greater Los Angeles and 

San Diego areas during the 1957 water year. 

As ~ridicated ,on figure 6, these annual imports have 

increased from 329, 000 acre-feet in 1945 to 928, 000 

acre-feet in 1957-a net increase of 182 percent. About 
ANNUAL ,RUNOFF FOR THE WATER YEAR 1955-56 13 

1000~----------~------------~-----------.-------------.------------, 

t:w 

I.J.J 

LL.. 

w 

0::::: 

u 

<t 

LL.. 

BOO 

0 600 (/) 

0 

z 

<t 

----Wet 

I 

i' 

I 

I 

I 

I 

I 

General c!tinotic distribution 

I 

Dry .L Wet Dry 

I 

I 

I 

I 

I 

I 

Annual diversion from the Colorado River by the (/) 

::) 

0 ,, Metropolitan Water District of Southern :r: 

1-

z 

~ 

LL.. 0400 

z 

::) 

0::::: 

_J 

<t 

::) 

z 

z 

<t 

200t------

I 

I 

I 

I 

I 

::::::: ::::::::::::::::::::::::::::;An nua I ):l_1yers1q~::: f ror11 :::the_:: Owens :::Y a It ey.::::::::::::::::::::: 

dW~mlllil.lili ~1111 Ill, II Ill IIIII 111111 Ill ill 1.11' -llilli !ill.~ II· I il!i I !!~.1 l:f.i ilil~ II ilillilllililli II i'lillilli liilliil.illl I I fl!f OL---~~~~~~~~~~~~~~~~~~~~~~~~~~~=-~~ 

1910 1920 1930 1940 1950 1960 

Figure 6. -Water imported into southern California. 

45 percent of the annual water requirements in the 

coastal areas are now met by imported water. 

ANNUAL RUNOFF FOR THE WATER YEAR 1955-56 

Annual runoff data for the water year ending September 30, 1956, for all southern California gagingstation records currently published by the Geological 

Survey, are presented in table 4. The mean and 

median values of the annual runoff for the period of 

record and the relation of the annual runoff to the base 

mean are included for the stations with a record of 

sufficient length. 

Areal distribution 

The normal storm tracks moving over southern 

California are such that the precipitation along the 

coast generally decreases from north to south. The 

eastward movement of these storms is blocked by the 

high mountain barriers which cause the greatest precipitation on the windward side of these barriers. 

Across the barriers the precipitation decreases rapidly 

to near zero in the desert areas. 

A generalized areal distribution of the annual runof:r* 

for the water year ending on September 30, 1956, is 

shown on figure 7. The runoff quantities used to 
14 WATER RESOURCES SUMMARY FOR SOUTHERN CALIFORNIA, 1957 

Table 4.--Annual runoff for the water year 1955-56 

[Basic data furnished by: acity of San Diego; bcal1forn1a Water and Telephone Co.; cHelix Irrigation District; dVista Irrigation District; hMontecito County Water District; ic1ty of Santa 

Barbara. 

Records furnished by: 6 0range County Flood Control District; fLos Angeles County Flood Control 

District; uventura County Water Resources Division. 

Imported water: *Adjusted for 21,690 acre-ft of Colorado River water; **Adjusted for 31,590 acre- ft of Colorado River water; tAdjusted for 12,770 acre-ft of Colorado _River water; ttAdjusted 

for 4,005 acre-ft of Owens River water] 

Basin and stream 

fACIFIC SLOPE BASINS 

Tia Juana River basin: 

Drainage 

area 

(square 

miles) 

Cottonwood Creek at Morena Dam a -------- 120 

Cottonwood Creek at Barrett Dam, near Dulzura-------------------------- 250 

Cottonwood Creek above Tecate Creek, 

near Dulzura-------------------------- 316 

Campo Creek near Campo------------------ 84 

.Tia Juana River near Dulzura------------ 478 

Tia Juana River near Nestor-------------~,668 

Otay River basin: 

Jamul Creek near Jamul------------------

Otay River at Savage Dam----------------

Sweetwater River basin: 

Sweetwater River at Loveland Dam, near Alpine b ------------------------- Sweetwater River at Sweetwater Dam b ----

San Diego River basin: 

Boulder Creek at Cuyamaca Reservoir, 

near Julianc ------------------------- San Diego River at El Capitan Dam a -----

San Diego River near Santee-------------

San D1egu1to River basin: 

Santa Ysabel Creek at Sutherland Dam----

Santa Ysabel Creek near Ramona----------

Guejito Creek near San Pasqual----------

Guejito Creek at San Pasqual------------

Santa Maria Creek near Ramona-----------

San D1egu1to River at Lake Hodgesa -----

San Luis Rey River basin: 

San Luis Rey River at Lake Henshaw, 

near Mesa Granded -------------------- San Luis Rey River at Monserate Narrows, near Pala-----------------------------

San Luis Rey River near Bonsall---------

San Luis Rey River at Oceanside---------

Santa Margarita River basin: 

Temecula Creek at Vail Dam, 

near Temecula-------------------------

Murrieta Creek at Temecula--------------

Santa Margarita River near Temecula-----

Santa Margarita River near Fallbrook----

Santa Margarit~ River at Ysidora--------

San Juan Creek basin: 

72 

98 

100 

181 

12.0 

190 

380 

58 

110 

24 

28 

58 

303 

209 

383 

514 

557 

319 

220 

592 

645 

740 

~955-56 annual 

Acrefeet 

Acre- per 

feet square 

mile 

131 

1,380 

0 

22 

44 

0 

1,140 

1,047 

542 

1,172 

398 

1,801 

178 

860 

792 

564 

412 

-699 

1,782 

1,150 

0 

0 

1,370 

997 

3,750 

1,750 

0 

'-:.: ·' 

1.09 

5.52 

0 

.26 

.09 

0 

1.58 

10.7 

5.42 

6.48 

33.2 

9.48 

.47 

14.8 

7.20 

23.5 

14.7 

0 

-2.31. 

8.53: 

3.00 

0 

0 

4.29 

4.53 

6.33 

2. 71 

0 

San Juan Creek near San Juan CapistranoTrabuco Creek near San Juan Capistranoe 

110 5, 710 

36.5 1,360 

5.19 . 37.3 

Aliso Creek basin: 

Aliso Creek at El Toro 6 ---------------- 8.5 427 50.2 

runoff Period of record :Sase mean Departure 

from 

base '-'ength mean (years) 

(percent) 

-99 

-91 

-99 

-93 

-93 

-100 

-86 

-89 

-80 

-92 

-100 

-61 

-17 

20 

11 

20 

20 

20 

21 

16 

20 

12 

69 

12 

11 

41 

35 

23 

9 

11 

17 

40 

34 

13 

27 

24 

33 

26 

33 

31 

32 

28 

26 

26 

Mean 

annual 

runoff 

(acrefeet) 

10,910 

9,240 

7,750 

2,310 

12,520 

38,300 

Medlar 

annua 

runoff 

(acrefeet) 

Mean 

annual 

runoff 

1920-55 

(acrefeet) 

6,100 11,250 

4,200 ------

1,880 ------ 1,520 ------ 4,200 ------ 8,690 ------

4,310 2,000 ------

2,090 

10,980 

20,920 

15,570 

731 

557 

4,060 

1,060 4,360 

5,000 ------ 3,620 20,410 

8,500 12,340 

140 

650 

22,030 12,700 24,410 

8,470 

18,530 

15,930 

8,900 

7,750 

17,490 

22,160 

25,390 

2,820 ------ 7,170 21,970 

1,450 ------

4,940 

2,170 

7,190 

8,460 

9,390 

9,810 

9,380 

19,030 

23,090 

27,450 

3,740 580 3,530 

550 220 514 
ANNUAL RUNOFF FOR THE WATER YEAR 1955-56 15 

Table 4.--Annual runoff for the water year 1955-56--Continued 

1955-56 annual runoff Period of record Base mean 

Basin and stream 

Peters Canyon Wash basin: 

Drainage 

area 

(square 

miles) 

San Diego Creek near Irvine------ --------

Santa Ana River basin: 

Santa Ana River near Mentone-----

Mill Creek near Yucaipa----------

Mill Creek near Mentone----------

Plunge Cree.k near East HighlandsSanta Ana River near San 

Bernardino---------------------

Little San Gorgonio Creek near Beaumont------------------

San Timoteo Creek near Redlands--

San Timoteo Creek near Lorna Linda 

East Twin Creek near 

Arrowhead Springs-------------- Waterman Canyon Creek near Arrowhead Springs--------------

City Creek near Highland---------

Devil Canyon Creek near San Bernardino-----------------

Lytle Creek near Fontana---------

Cajon Creek near Keenbrook-------

Lone Pine Cr~ek near Keen~rook--­

Lytle Creek ~east channel) 

at San Bernardino--------------

Warm Creek near Colton-----------

Santa Ana River at Riverside 

Narrows, near Arlington--------

Day Creek near Etiwanda----------

Cucamonga Creek near Upland------

San Jacinto River near San Jacintc 

Bautista Creek near Hemet--------

San Jacinto River near Elsinore--

Temescal Creek near Corona-------

San Antonio Creek near ClaremontSanta Ana River below Prado Dam--

Santa Ana River at county line, 

below Prado Dam----------------

Santiago Creek at Santiago Dam, near Villa Park----------------

Santiago Creek near Villa Park----

Santiago Creek at Santa Ana-------

Santa Ana River at Santa Ana-----

San Gabriel River basin: 

East Fork San Gabriel River 

near Camp Boni ta.f-. ------------- , 

West Fork San Gabriel River ~ at Camp Rincon f ---------------

San Gabriel River near Azusa-----

Rogers Creek near Azusa----------j Fish Creek near Duarte-----------

San Gabriel River below Santa Fe 

Dam, near Baldwin Park---------

San Dimas Creek near San Dimas---

Dalton Creek near Glendora-------~ 

Li8i~~d~;~~~-~:==~-~=~:---------~ San Jose Creek near Whittier/---~ 

San Gabriel River above 1 

Whittier Narrows Dam-----------

San Gabriel River at Pico f -------

San Gabriel River at Spring Street, near Los Alamitos------

Brea Creek below Brea Dam, near Fullerton-----------------

Brea Creek at Fullerton e ---------

Fullerton Creek below Fullerton 

Dam, near Brea-----------------

Fullerton Creek at Fullertone ---- Coyote Creek near Artes·ia f -------

Carbon Creek near Yorba Linda-----

202 

39.9 

16.9 

2.61 

123 

8.6 

4.55 

19.8 

6.16 

46.9 

40.9 

15.0 

4.8 

10.1 

140 

39.4 

717 

16.9 

63 

83.8 

2,418 

88.2 

102 

211 

6.4 

6.5 

231 

18.3 

7.5 

2.7 

85.2 

584 

23.4 

26.2 

6.2 

110 

20.4 

Acrefeet 

Acre- per 

feet square 

mile 

Departure 

from 

base 

mean 

(per 

cent) 

987 ------ ---

26,890 133 

9,870 247 

351 ------ 2,910 172 

2,950 ------

23 8.81 

194 1.58 

1,170 ------

1,660 193 

896 197 

2,860 144 

1,410 229 

13,450 287 

2,110 51.6 

199 13.3 

311 

19,630 

*26 ,440 

1,300 

2,100 

4,800 

56 

0 

35 

6,820 

72,440 

71,310 

271 

208 

34.3 

1.42 

0 

404 

7,683 122 

628 7.49 

1,290 ------ 3,810 1.58 

22,200 252 

12,350 121 

36,380 172 

772 121 

1,100 169 

0 0 

799 43.7 

356 47.5 

211 78.1 

4,990 58.6 

**8,960 ------ t 11,280 ------

9,390 16.1 

378 16.2 

551 21.0 

310 ------ 1,100 177 

7,280 66.2 

206 10.1· 

-52 

-60 

-85 

-51 

-53 

-62 

-40 

-55 

-69 

-83 

-51 

-67 

-63 

-80 

-58 

-32 

-73 

-80 

-55 

-75 

-65 

-66 

-63 

-76 

-15 

-67 

+30 

Length 

(years) 

7 

60 

28 

17 

37 

11 

8 

30 

2 

36 

38 

37 

37 

52 

36 

25 

27 

36 

26 

27 

27 

36 

9 

40 

27 

39 

16 

37 

25 

36 

27 

33 

23 

29 

61 

39 

39 

14 

39 

36 

18 

27 

1 

28 

29 

14 

26 

15 

21 

27 

7 

Mean 

annual 

runoff 

(acrefeet) 

Medlar. 

annual 

runoff 

(acre 

feet) 

Mean 

annual 

runoff 

1920-55 

(acrefeet) 

1,220 ------ -------

61,750 51,700 

23,960 17,40( 

1,980 510 

6,430 

65 

1,090 

3,390 

1,970 

7,450 

1,010 

430 

2,460 

1,300 

5,600 

2,330 1,650 

31,560 25,900 

6,540 4,270 

956 360 

40,650 

3,920 

5,550 

24,000 

449 

29,900 

2,960 

4,130 

13,600 

2,800 43 

15,710 11,600 

12,970 

3,970 

14,760 

7,800 

580 

2,080 

55,680 

24,500 

1,300 

3,420 

1,900 

7,530 

2,340 

29,730 

6, 720 

1,160 

53,860 

3,950 

5, 710 

24,550 

16,120 

11,220 

4,750 

19,300 

51,470 34,800 48,910 

46,910 26,100 49,640 

110,000 79,600 104,200 

2,130 1,090 2,240 

2,860 1,810 3,010 

3,140 

492 

6,040 

1,880 

220 

3,840 

3,290 

5,860 

32,120 14,000 34,270 

19,020 

492 

849 

543 

5,840 

188 

1,990 

220 

364 

220 

3,150 5,620 
16 WATER RESOURCES SUMMARY FOR SOUTHERN CALIFORNIA, 1957 

Table 4.-Annual runoff for the water year 1955-56-:-Continued 

1955-56 annual runoff Period of record Base mean 

De parDrain- Acre- ture Mean Medlar Mean 

age feet from annual annual annual 

Basi.n and stream area Acre- per base wength runoff runoff runoff 

(square feet square mean (years} (acre- (acre 1920-55 

miles} mile (per- feet} feet) (acrecent) feet} 

Los Angeles River basin: 

Los Angeles River at Sepulveda Dam- 155 tt13,405 86.5 --- 13 12,,770 9,260 ----- Pacoima Creek near San Fernando f -- 28.2 1,250 44.3 -82 39 6,650 .5,110 6,920 

Tujunga Creek below Mill Creek, 

near Colby Ranch f --------------- 64.9 1,810 27.9 --- 8 4,000 ------ ------ Tujunga Creek near Sunland f ------- 106 4,700 44.3 -78 39 20,270 10,900 21,190 

Haines Creek near Tujunga---------- 1.2 31 25.8 --- 24 282 140 ·----- Little Tujunga Creek near San Fernando f -------------- 21.0 381 18.1 -81 28 1,860 510 2,020 

Tujunga Creek below Hansen Dam----- 148 25 .17 --- 16 15,020 2,900 ------ Los Angeles River at Los Angeles/- 510 35,890 70.4 -12 27 41,770 25,300 40,790 

Arroyo Seco near Pasadena---------- 16.4 2,160 132 -66 42 6,660 3,620 6,270 

Los Angeles River near Downeyf ---- 614 66,440 108 --- 28 69,860 44,900 ------ Sawpit Creek near Monrovia--------- 5.3 835 158 -56 39 1,820 1,300 1,880 

Santa Anita Creek near Sierra Madre 10.5 2,230 212 -49 40 4,140 2,610 4,360 

Little Santa Anita Creek near Sierra Madre---------------- 1.9 278 146 -58 39 637 360 665 

Eaton Creek near Pasadena---------- 6.5 895 138 -68 38 2,690 1, 710 2,820 

Rio Hondo near Montebello f -------- ------ 16,180 ------ -59 28 38,010 26,800 39,240 

Mission Creek near Montebello f ---- ------ 2,310 ------ --- 26 11,510 10,900 ------ Rio Hondo near Downey f ------------ ------ 14,540 ------ --- 28 19,550 7,960 ------ Los Angeles River at Long Beachf -- 822 96,820 118 +10 27 ~02,800 69,500 88,040 

Ballona Creek basin: 

Ballona Creek near Culver City f --- 88.6 34,590 390 --- 28 ------ ------ ------

Topanga Creek basin: 

Topanga Creek near Topanga Beach f - 17.9 1,030 57.5 -72 25 3,920 1,450 3,690 

Malibu Creek basin: 

Malibu Creek at Crater Camp, 

near Calabasas/ ----------------- 103 4,680 45.4 -63 25 14,050 4,630 12,760 

Santa Clara River basin: 

Santa Clara River at Los AngelesVentura county line u ------------ ------ 5,510 ------ --- 4 ------- ------ ------ Piru Creek above Piru Reservoir---- ------ 10,850 ------ --- 1 1------- ------ ------ Piru Creek below Santa Felicia Dam- ------ 8,100 ------ --- 1 1------- ------ ------ Piru Creek near Piru--------------- 432 8,400 19.4 -79 29 39,700 18,100 40,600 

Hopper Creek near PiruU ----------- 23.0 1,640 71.3 --- 24 3,480 1,590 ------ Sespe Creek near Wheeler Springs--- 50 2,550 51.0 --- 8 3,460 ------ ------ Se-spe Creek near Fillmore---------- 254 29,600 117 -58 29 70,660 39,800 70,980 

Santa Paula Creek near Santa Paula- 39.8 5,260 132 -60 29 13,320 6,950 13,330 

Ventura River basin: 

Matilija Creek above reservoir, near Matilija Hot Springs-------- 51 7,940 156 --- 8 9,630 ------ ------ Matilija Creek at Matilija Hot Springs------------- 55 6,600 120 -68 29 20,910 10,000 20,910 

North Fork Matilija Creek at Matilija Hot Springs u ----------- 15.5 2,500 161 -57 27 6,150 2,970 5,860 

San Antonio Creek at Casitas Springsg ---------------- ------ 1,150 ------ --- 7 2,440 ------ ------ Coyote Creek near Ventura---------- 41.1 6,180 150 -28 28 8,980 3,550 8,620 

Ventura River near Ventura--------- 187 15,040 80.4 -68 29 47,470 23,750 46,590 

Carpinteria Creek basin: 

Carpinteria Creek near Carpinteria- 13.8 357 25.9 --- 15 1,070 290 ·-----

Atascadero Creek basin: 

Atascadero Creek near Goleta------- 18.3 2,640 144 --- 15 1,520 580 ------ San Jose Creek basin: 

San Jose Creek near Goleta--------- 5.54 2,230 392 --- 15 992 580 .. _____ 
ANNUAL RUNOFF FOR THE WATER YEAR 1955-56 17 

Table 4.--Annual runoff for the water year 1955-56--Continued 

Basin and stream 

Santa Ynez River basin: 

Santa Ynez River at Jameson 

Lake, near Montecitoh ---------- Santa Ynez River above Gibraltar 

Dam, near Santa Barbara i ·-------

Santa Ynez River below Gibraltar 

Dam, near Santa Barbarai ------- Santa Ynez River below Los 

Laureles Canyon, near Santa Ynez 

Santa Cruz Creek near Santa Ynez--

Cachuma Creek near Santa Ynez-----

Santa Ynez River near Santa Ynez--

Santa Agueda Creek near Santa Ynez 

Zanja Cota near Santa Ynez--------

Santa Ynez River at Grand 

Avenue, near Santa Ynez---------

Santa Ynez River at Solvang-------

Santa Ynez River at Buellton------

La Zaca Creek at Buellton---------

Santa Ynez River near Buellton----

Santa Ynez River at Santa Rosa 

Damsite, near Buellton---------- Santa Ynez River at Cooper's Reef, near Lompoc--------------- Santa Ynez River below Santa 

Rita Creek, near Lompoc--------- Salsipuedes Creek near Lompoc----- Santa Ynez River at narrows, near Lompoc--------------------- Santa Ynez River near Lompoc------ Santa Ynez River at H Street, near Lompoc--------------------- Santa Ynez River at 13th Street, near Lompoc--------------------- Santa Ynez River at barrier, near Surf-----------------------

San Antonio Creek basin: 

Drainage 

area 

(square 

miles) 

13.8 

216 

216 

277 

73.8 

20.5 

435 

56.4 

579 

39.5 

668 

47.0 

790 

790 

816 

895 

1955-56 

Acrefeet 

752 

12,654 

3,480 

9,780 

9,410 

1,750 

1,900 

1,200 

1,380 

4,760 

12,140 

15,820 

76 

16,620 

16,930 

15,710. 

16,940 

15,610 

28,760 

28,860 

26,700 

23,670 

27,310 

San Antonio Creek near Casmalia--- -------- 3,970 

Santa Maria River basin: 

Cuyama River near Ventucopa------- Cuyama River near Santa Maria-----

Alamo Creek near Santa Maria------

Huasna River near Santa Maria-----

Sisquoc River near S1squoc--------

La Brea Creek near Sisquoc-------- Tepusquet Creek near Sisquoc------ Sisquoc River near Garey---------- Santa Maria River at Guadalupe----

Arroyo Grande basin: 

Arroyo Grande at Arroyo Grande----

THE GREAT BASIN 

Sal ton Sea basin: 

Whitewater River at Whitewater'---

Tahquitz Creek near Palm Springs--

Palm Canyon Creek near Palm Springs-------------------- Andreas Creek near Palm Springs--- Coyote Creek near Borrego Springs- Palm Canyon Creek near Borre~o Springs-----------------

Mojave River basin: 

Deep Creek near Hesperia---------- West Fork Mojave River near Hesperia------------------- Mojave River at lower narrows, near Victorville----------------

Mojave River at Barstow-----------

Mojave River at Afton-------------

Antelope Valley: 

Big Rock Creek near Valyermo------ . Little Rock Creek near Ll. ttle Hockf --------------

90 

912 

87.7 

119 

290 

86.7 

28.9 

442 

1,763 

106 

57.4 

94.0 

8.78 

21.7 

137 

74.8 

530 

23.0 

49.0 

2,630 

3,730 

3,330 

10,430 

14,060 

2,070 

1,160 

8,360 

4,200 

17,320 

5,320 

538 

.2 

946 

1,580 

267 

16,980 

2,120 

21,740 

0 

902 

4,800 

5,470 

annual runoff Period of record l3ase mean !DeparAcre- ! ture · feet : from 

per ; base '-'ength 

square 1 mean (years) 

mile · (percent) 

54.5 

58.6 

16.1 

35.3 

128 

85.4 . 4.37: 

21.3 

21.0 

1.92 

24.9 

332 

36.4 

36.5 

32.7 

29.2 

4.09 

38.0 

87.6 

48.5 

23.9 

40.1 

18.9 

2.38 

163 

92.7 

0 

108 

12.3 

124 

28.3 

41.0 

209 

112 

-80 

-59 

-73 

-17 

+16 

-100 

-62 

-91 

-63 

-100 

-60 

-59 

25 

36 

36 

9 

14 

6 

26 

15 

2 

2 

18 

2 

15 

4 

2 

2 

2 

15 

4 

31 

9 

2 

3 

1 

11 

26 

13 

26 

13 

13 

13 

15 

15 

16 

7 

9 

21 

8 

6 

6 

43 

44 

31 

26 

6 

33 

24 

Mean 

annual 

runoff 

(acrefeet) 

Mediar: Mean 

annual annual 

runoff runoff 

(acre- 1920-55 

feet)· (acrefeet)' 

4,320 2,010' ~.840 

30,040 11,500 30,540 

25,850 

1

17,380 

7,380 

2,220 

1

63,400 

1,680 

31,220 

7,960 

5,430 

14,500 

720 

9,920 

188 22 ------

5,300 2,170 ------

85,950 30,900 ------

3,850 

14,770 

3,210 

13,830 

17,190 

2,820 760 

16,430 

14,120 

2,750 

7,240 

1,520 

5,600 

11,200 

580 

430 

6,660 

2,100 

13,970 

12,540 

16,100 8,690 14,940 

5,320 

1, 770 

3,490 

1,450 

1,930 

391 

940 4,390 

55,110 ~1,700 44,270 

31,650 ~0,300 24,510 

56,580 ~3,400 58,270 21,430 72 25,690 

2,110 r----- ------

11,090 6,780 12,100 

12,670 6,810 13,500 
-'() 

"V 

(' 

/ 

-- 1 - - r ----- - -----'--:-- ------r---

~ 

'-'I// I \/ ~>~~ ~ L, 

), L f.r ', \ 'tL / 

0 B 1

1

SPO :::-~/ 

L.., 

l_-, 

/ 

(' 

~ 0 'C::9 

EXPLANATION 

Departure from 1920-55 mean annual runoff, in percent 

+30 

~ to -10 

[:;:;::-:-:)5'!,j 

-11 to -40 

fSD!EO -41 to -70 

[/d 

-71 to -100 

"""- "' -....J 

K 

0 

c 

10 0 50 Miles 

'r~·~ /,..,...-/ ....___./ .· 

\ r 

,/_j - ,- \. 

--. ,..L._./ l I \.. ~ ... 

,~-~.~ 

<'..-' 

t: r -· E / .~ 

R \.... 

/ N .....--- ........ 

\ 

""'-.-.._ __ .-----.. 

\ \. 

E 

4 tv ~ 

~ 

~ 

,............,.. . ...-.,....,. 

1>--o~ E ) \ 

\ 

~~'-".~---:-

~<eJ· -~~r . '· ~ . [ "· ~-- I 

j \..u\:...~---~-----:---":", ·.::· .: :'\. / ...... < ,_,__ ____ ·. • so~J ·"'·. - .•. ··"' "-(_)• •· ~-"~-\- .\ ;; - ... . . .. . -- i· :.: . j' . /"_·· ..... Y-.J.c~ '-· r~ _1-· -, :: r~..,-.-! '-

/';-·~: A'~N-:- 0 I E ,G 0 \ 

~·-'r-( ;.90, R·~~C~;; /·r,~:Y:>+- ·-·.,s~~.~. . :" .· River.f"' r . • 1 

~-~~ . , a\~f':_:~ _r:- _··_{; San Diegolr:::\0 _ , •• ~~}'-' ~ )_(;_'/. ) 

<~ ''. ' '(''-:"-' •.. :• ) 

_; . .-":-~ /~- .:~~ ~, 

Figure 7. -Areal distribution of annug-1 runoff for the water year 1955-56. 

..... 

~ 

~ 1---,3 

trj 

:;.:1 

:;.:1 

trj 

U1 

0 

q 

~ trj 

U1 

U1 

q 

~ 

~ 

~ 

~ 

0 

:;.:1 

U1 

0 

q 

1---,3 

p:: 

trj 

:;.:1 

2: 

n 

:t> 

~ ~ 

0 

:;.:1 

~ 

? 

..... 

co 

(J1 

-.J 
ANNUAL RUNOFF FOR THE WATER YEAR 1955-56 19 

define this distribution were obtained from table 4; the 

quantities are relative as they express the departure, 

in percent, of the runoff for the 1956 water year from 

the mean of the 35-year period 1921-55. 

The 1956 water year was a very dry year-the 

12th year in a series of dry years-and the annual 

runoff from many valley streams in the agricultural 

areas was zero or nearly zero, representing departures as much as 100 percent below the 35-year 

base mean. 

In sharp contrast, and reflecting precipitation on the 

paved streets and roofs of buildings, annual runoff in 

many highly urbanized valley-floor areas in or near 

metropolitan Los Angeles exceeded the base mean by 

as much as 30 percent. Pepartures of this magnitude 

-are (fig. 7) quite comparable to the departures 

experienced in the relatively natural areas at the 

extreme northern end of coastal southern California. 

Unit runoff 

Unit rates of runoff generally decrease rapidly as 

the streams cross the valley-floor areas and discharge into the ocean. In the predominantly agricultural areas, the 1956 runoff into the ocean was zero from 

the basins of the Tia Juana, San Luis Rey, and Santa 

Margarita Rivers. In contrast, the highly urbanized 

areas tributary to the Los Angeles River discharged 

into the ocean the equivalent of 118 acre-feet per 

square mile, or 2. 2 inches, over the basin. The street 

drainage in the Beverly Hills and Hollywood areas 

produced a 1956 runoff of 390 acre-feet per square 

mile, or 7. 3 inches, over the Ballona Creek basin. 

INT.-DUP. SBC., WASH., D.C. H950