In 1960, California voters approved financing for construction of
the initial features of the State Water Project (SWP).
The project includes some 22 dams and reservoirs, a Delta
pumping plant, a 444-mile-long aqueduct that carries water
from the Delta through the San Joaquin Valley to
Southern California.
About 30 percent of California’s total annual water supply comes
from groundwater in normal
years, and up to 60 percent in drought years. Local communities’ usage
may be different; many areas rely exclusively on groundwater
while others use only surface
water supplies. Contrary to popular opinion, groundwater does
not exist in underground lakes.
Many cities rely on local water projects for all or a portion of
their supplies. These projects typically were built and are
operated by local public water districts, county water
departments, city water departments or other special districts.
Nearly 600 special purpose local agencies in California provide
water to their areas through local development projects and
imported supplies.
