Bulletin 1.pdf - California Department of Water Resources - State of ...

526 WATER RESOURCES OF CALIFORNIA
Number
on
Plate 2
TABLE 76
AREAS OF DRAINAGE BASINS, COLORADO DESERT AREA
In Square Miles
(Only Figures in Bold Face Type Are Carried Into "Totals, Colorado Desert Area")
Stream or stream group basin
Mountains Valley
and and
foothills mesa
Totals
1 Mojave Desert Group_______________________________ 5,833 2,T64. 8,59T
2 Whitewater River Basin. ____________________________ l,OT4. 500 l,5T4.
3 West Salton Sea Group_____________________________ 84 341 425
4 Carrizo Creek Group___ . ____________________________ 969 489 1,458
5 Coyote Wash Group________________________________ ,
96 182 2T8
6 Imperial Irrigation District Group. ___________________ 11 1,683 1,694
7 East Salton Sea Group______________________________ 63T TTl 1,4.08
Direct drainage to Colorado River
8-1 Pilot Knob Group________________________________ 81 231 312
8-2 Yuma Group____________________________________ 345 610 955
8-3 Blythe Group____________________________________ 155 563 718
8-4 Needles Group___________________________________ 644 1,667 2,311
Colorado River direct_____________________________ 1,225 3,OT! 4,296
TOTALS, COLORADO DESERT AREA IN
CALIFORNIA___________________________ 9,929 9,801 19,T30
normal. Prevailing winds are from the west, with highest velocities in
the spring. Of the 20 precipitation stations in the Area that have unbroken
records of 10 or more seasons, that at Indio has the longest record, being
unbroken since 1878. The 20 stations now maintained are insufficient to
cover adequately the 19,730 square miles in the Area.
Maximum recorded seasonal precipitation in the Area occurred at
Raywoods Flat, at an elevation of 7,200 feet in San Bernardino County,
in 1936-37, and amounted to 68.34 inches. Ave:rage seasonal precipitation
at this station is 39.22 inches. Palm Springs, at an elevation of 584 feet
in Riverside County, recorded no precipitation during 1896-97, the
seasonal average at this station being 5.77 inches. At Bagdad, at an elevation
of 784 feet in San Bernardino County, there was no precipitation
during 1917-18, and average seasonal precipitation is only 2.24 inches.
Elevations of the 20 present stations range from 250 feet below sea level
to 7,200 feet above.
Continuous recorders are maintained at nine precipitation s,tations
in the Area, as listed in Table 78, the first having been installed at Coachella
in 1939. Records provided by these recorders are not of sufficient
length to show satisfactorily rainfall intensities to be expected in the
Area. Precipitation stations with records of less than 10 years are listed
in Table 79. Data presented in Table 80, and on the bar diagrams of
Plate 88, "Distribution of Precipitation at Selected Stations, Colorado
Desert Area," relate to monthly distribution of precipitation at four
stations considered representative of the Area with respect to elevations
and topography. At each of these stations the minimum recorded precipitation
for every month of the year was zero.