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

WATER RESOURCES OF CALIFORNIA
RELATED SUBJECTS
For reasons later indicated, certain subjects relating in various
degree to the water resources of California have been excluded from the
scope of this bulletin.
The relatively large water storage capacity of valley fills in California
comprises one of the more important natural resources of the
State, its great value stemming from its natural regulation and conservation
of precipitation and runoff. However, ground water storage
capacity in itself is not an additional water resource, and has not been
evaluated in the present inventory. It is briefly discussed in the ensuing
section, "Natural Regulation of Water Resources."
Recent technological advances have called attention to sea water
conversion and to cloud seeding as possible means of adding to the water
resources of California. Similarly, reclamation of sewage and waste
waters for beneficial use, which already has been accomplished in certain
instances, is under discussion and investigation. Possible augmentation
of the water resources of the State by these methods has not been considered
in the present inventory. However, the three methods are briefly
discussed in ensuing sections, and a tentative evaluation of potential
reclamation of sewage and waste water is contained in an appendix to
this bulletin.
Natural Regulation of Water Resources
The extensive ground water basins of California provide natural
regulation for runoff from tributary mountain and foothill drainage
areas, and for precipitation directly on overlying mesa and valley floor
lands. More than half of the State's water presently utilized on irrigated
lands, and for domestic, municipal, and industrial purposes, is regulated
in ground water basins.
Additional natural regulation of water resources would be provided
if presently unused ground water storage capacity were utilized to the
full extent of safe yield of the ground water basins. Furthermore, as
additional surface water supplies are developed and made available for
storage in ground water basins, safe yield of the underground reservoirs
will be increased. Under ultimate development of water resources in the
State, the maximum amount of firm water could be made available on
demand through operation of surface reservoirs on an average yield
basis in conjunction with cyclic underground storage. Such coordinated
operation would necessitate an adequate supply of energy to pump
ground water in a series of dry years.
Usability of a ground water basin as a natural regulator of water
resources is dependent upon method and rate of replenishment of stored
water, as well as extraction from the basin for beneficial use. The largest
bodies of usable ground water storage capacity in California are in the
Sacramento and San Joaquin Valleys in the Central Valley Area. Other
important natural regulators of lesser magnitude are those in Santa
Clara, Napa, Santa Rosa, and Livermore Valleys, and the Niles Cone in
the San Francisco Bay Area; the Pajaro, Salinas, Santa Maria, and Santa
Ynez River Basins in the Central Coastal Area ; the Ventura, Santa Clara,
Los Angeles, San Gabriel, and Santa Ana River Basins in the South
Coastal Area; Antelope, Owens, and Mojave Valleys in the Lahontan
Area; and the Coachella Valley in the Colorado Desert Area.
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