Surface water is produced by melted snow runoff and rainfall in northern California that is captured and stored at Lake Oroville. When needed, it is released into the Feather River, which flows into the Sacramento River to the Sacramento-San Joaquin Delta. In the Delta, the State Water Project pumps water from its Delta pumping plant into the California Aqueduct.
Some water is pumped into the North Bay Aqueduct to supply Napa and Solano counties and supply flows into the South Bay Aqueduct to serve areas in Alameda and Santa Clara counties. The rest continues flowing south to southern California ending its long journey at various reservoirs and then to treatment facilities, reaching its final destination to millions of homes and businesses.
In winter, when water supplies are generally high, but demands are low, water is diverted and stored in San Luis Reservoir south of the Delta. In spring, when demands increase as farmers begin planting crops, water is taken from both the Delta and San Luis Reservoir. As summer approaches, additional water is released from Lake Oroville and Delta pumping is increased to meet the needs of cities and farms.
Photo Credit: California Department of Water Resources