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

24 WATER RESOURCES OF CALIFORKIA
No. 31 discussed briefly the plans for diversion and transmission of
Colorado River water to the South Coastal Basin under the project of
the Metropolitan Water District of Southern California.
OBJECTIVE OF STATE-WIDE WATER RESOURCES INVESTIGATION
Although investigations that led to the State Water Plan were conceived
as comprehensive and state-wide, they were never completed in
that pattern. All phases were not considered for certain areas of the State,
and important projects were omitted and left for future study. Furthermore,
although adopted by the Legislature in 1941, the plan was formulated
in 1930 and was based on investigations and studies conducted in
the preceding decade. Since 1930 the population of California has almost
doubled, and the need for flood control, water conservation, and power
has more than kept pace with population and industrial growth.
Objective of the current state-wide water resources investigation is,
therefore, the preparation of a revised and more complete plan for the
fullest conservation, control, and utilization of the water resources of
California, both surface and underground, to meet present and future
water needs for all beneficial purposes and uses in all areas of the State,
so far as is practicable. This plan has been dt'signated "The California
Water Plan."
SCOPE OF BUUETlN
The present bulletin-the first of four to be concerned with preparation
of the California Water Plan-comprises an inventory of the water
resources of the State. As the state-wide water resources investigation
progresses, this bulletin will be followed by others concerned with present
utilization and ultimate water requirement in California, the California
Water Plan for development of the water resources of the State to meet
the ultimate requirement, and finally a summary of the t'arlier bulletins
and restatement of the California Water Plan.
This bulletin outlines and describes the drainage basins of California
by major hydrographic areas. with a summary of "mountain and foothill"
and "valley and mesa" lands. It discusses conditions relating to
precipitation and runoff, on a state-wide basis, and contains estimates of
the probable frequency of floods on principal streams. Since this bulletin
comprises an inventory of the water resources of the State, it includes
available records of precipitation and runoff at most stations or points
of measurement, and records or estimates of the natural flow of streams
of all drainage basins. Finally, it summarizes available data regarding
quality and suitability for beneficial uses of both the surface and underground
waters of California.
Consideration is given to the principal sources of ground waters of
the State. These consist of surface inflow from mountain and foothill
lands tributary to ground water basins, and precipitation on valley and
mesa lands overlying the basins. However, subsurface inflow from tributary
drainage basins is not included in the present inventory. Subsurface
inflow is known to be locally significant in certain underground basins,
but in most tributary drainage areas the soil mantle is either nonwaterbearing,
or too thin to transmit appreciable subsurface flow. On a statewide
basis, the aggregate of such flow is small compared. with recharge of
ground water basins from surface runoff and from precipitation on overlying
lands.