Ground Water Atlas of the United States -
Segment 1 California Nevada
Ground-Water Withdrawals
Surface and ground water are used conjunctively in the north San Francisco Bay
area valleys. Several municipalities obtain a significant amount of their
supplies from imported surface water, either from the Russian River or the
aqueduct systems that serve San Francisco Bay area cities to the south.
Nonetheless, ground water is used for some municipal supplies, as well as for
irrigation, stock watering, and domestic uses.
Currently (1995), ground-water recharge and discharge are approximately in
balance on an average annual basis in most areas, and withdrawals in excess of
recharge are not common. However, because of the relatively limited storage
capacity of the aquifers, as well as water-quality concerns, the amount of
additional ground water that can be withdrawn without adverse effects is
restricted. Although lowering of the water table can allow infiltration of
additional recharge that might normally be rejected, withdrawal in excess of
recharge can deplete ground-water reserves and possibly cause the migration of
poor-quality water into wells. Careful monitoring of local and regional water
levels will always be necessary to ensure proper use of the resource.
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