WSP10396

• File Number: 8056
• Description: Drought Preparedness
• State: CO
• Basin: Statewide
• Date: 1/1/1964
• Author: USGS
• Title: General Effects of Drought on Water Resources on the Southwest
• Water Supply Pro - Doc Type: Report/Study

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GENERAL EFFECTS OF DROUGHT ON 1!TATER RESOURCES

B47

Many activities that depend npon surface water also
have been adversely affected by drought. Recreational
facilities have been affected by drying up of several
natural lakes in the northern part of the State. For
example, Mormon Lake, south of Flagstaff, has a nor-
mal surface area of 8112 square miles and is fed by the
natural runoff from 38.3 square miles, mostly a high
pine- forested plateau. The lake has never been known
to overflow and therefore is a measure of the residual
runoff from its drainage area, The lake was dry 'at
several times during the drought that ended in 1904,
but so far as known it contained water throughout the
period 1905-46, Since then the lake has been dry in
parts of the years 1947, 1948, 1951, and 1953-56. Sev-
eral other lakes and springs in the vicinity of Flagstaff
have had histories similar to that of Mormon Lake.
Emergency measures during the drought included
some rationing of water, hauling of water 40 miles by
rail for the city of ''ViUiams, and contracts for cloud
seeding to increase precipitation, The city of Yuma,
obtaining wate.r from the Colorado River, had con-
siderable expense in maintaining a channel between its
intake and the meandering river in periods when almost
all water was diverted upstream at Imperial Dam,
New sources of supply were developed, notably by
pumping from underground ,reservoirs. In fact, de-
velopment of new wells enabled municipal and irriga-
tion uses to expand during the drought, New supplies
have also been developed by surface storage, such as
the modification of Horseshoe Dam in 1950, when the
city of Phoenix increased the height of the dam by 4
feet and installed spillway gates to provide 76,100 acre-
feet of additional storage, available for release down
the Verde River as needed (fig, 14),

CALIFORNIA

In southern California the drought of 1945-56 was
of comparable magnitude to that of 1894--1904, and
more severe than any other dry period in 75 years of rec-
ord (1" B27, 136), Nevertheless, the economic effects of
this latest drought were minor, partly because the dry
period was interrupted by the wet yea.r 1952 but chiefly
because the wate.r shortages due to natural causes were
overshadowed by those created by expanding require-
ments of a rapidly increasing population, In the boom
created by urbanization and industrializa.tion, the effect
of the drought upon the State's economy was practically
negligible. The relative insignificance of the drought
is indicated by the fact that no part of the State was
designated a drought-disaster area eligible for Federal
aid,
Because most of California's precipitation falls dur-
ing the winter, relatively few agricultural products
depend upon soil water derived directly from precipita-

tion. Those products-grass suitable for winter forage
and hay, grains, and vegetables and other crops that
can grow throughout the mild winters of several coastal
valleys-grow during the season of least evapotranspi.
ration and greatest water surplus, and their yield is
dependent more upon the timing and intensity of the
rain than upon the annual total.
The deficiency in streamflow during the drought
years had some effect upon hydroelectric power, and
upon recreational facilities dependent upon the stream-
flow. The production by hydroelectric plants on
streams in the southern Sierra Nevada fluctuated some-
what with the streamflow in the drought years; it ranged
from 512 million kwh in dry 1949 to 809 million in
wet 1952, and was greater than 710 miUion kwh in 8
of t.he 11 years 1945-55. The detrimental effects of
drought. upon recreational activities resulted chiefly
from reduced inflow t.o lakes and reservoirs. For ex-
ample, Elsinore Lake sout.heast of Los Angeles was dry
in August 1951 for t.he first t.ime since records began
in 1915, and according to newspaper reports for the
first t.ime since 1859; in 1952 there was some ,recovery
but t.he lake was dry about half the t.ime during the 5
years 1952-56. Similarly, in Big Bear Lake and other
reservoirs where storage is reWllated. for irrig;ation or
municipal use, t.he wat.er in storage in 1951 was less
than it. had been for many years; there was some in-
crease in 1952, but the st.orage by the end of 1956 was
again near the minimum of record.
Although some rationing Or ot.her emergency meas-
ures were necessary in various localities during the
drought. years, these were overshadowed by activities
seeking more permanent. alleviation of wat.e.r shortages,
either by conservation of supplies already developed
or by development. of addit.ional supplies, Among the
conservation measures might. be noted the shift to agri-
cultural products of lower water requirements, as for
example in the Camarillo and Santa Paula di.stricts
of Ventura County where some lemon groves were re-
placed by lima beans because of t.he scarcity of water.
The cit.y of San Diego has used a water-saving tech-
nique since 1946 t.o reduce evaporation losses from its
reservoir syst.em: Water that could be stored either in
EI Capit.an or in Cuyamaca Reservoir has been stored
when possible in El Capitan Reservoir, because its stor-
age capacity per acre of surface area is more than 6
times that of Cuyamaca Reservoir, and evaporation
losses are therefore less per unit of stored water,
Great strides in water conservation have been made
by various industries in southern California, as pointed
out by Pickett (1956) :
* * * For example, when plans were first developed to es.
tablish the Lever Brothers Soap and Edible Oils Plant in Ban-