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.
A number of large population centers in California have developed
their own extensive water projects. The Hetch Hetchy
Project transports Tuolumne River water 156 miles
from the Central Sierra
Nevada to San Francisco and peninsula cities.
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.
