State Water Project

During an average water year, about half of the SCV’s water is imported, primarily through the State Water Project, which extends for more than 700 miles from north to south, terminating at Castaic Lake.

Water is first stored in Lake Oroville, located northeast of Sacramento. It then travels through various reservoirs, dams, power plants and rivers before reaching the Sacramento-San Joaquin Delta, a complex network of natural and man-made channels.

From the Delta, the water makes its way to the Harvey O. Banks Pumping Plant where it begins a 300 mile journey in the California Aqueduct. Then at the A.D. Edmonston Pumping Plant, the water is lifted 1,926 feet and enters more than eight miles of tunnels to cross the Tehachapi Mountains. From this point the water continues south through the West Branch of the California Aqueduct through Quail Lake, Pyramid Lake and finally into Castaic Lake.

Water is withdrawn from Castaic Lake and flows through large underground pipelines to supply the Agency’s treatment plants, the Earl Schmidt Filtration Plant and the Rio Vista Water Treatment Plant.

This water supply depends on several factors, including rainfall, snowpack, runoff, water in storage facilities, and pumping capacity from the Delta. The amount of water available for distribution is also influenced by the need to protect fish and wildlife, water quality, and environmental and legal restrictions. These factors determine how much the State Water Project is able to release to each of the contract agencies, such as SCV Water, each year. Sometimes we may get as much as 60% of our allotment, but during drought that could be 5%, or even zero.

The California State Water Project

The California State Water Project (SWP) is a multi-purpose water storage and delivery system that extends more than 705 miles -- two-thirds the length of California. A collection of canals, pipelines, reservoirs, and hydroelectric power facilities delivers clean water to 27 million Californians, 750,000 acres of farmland, and businesses throughout our state.

Visit the California Department of Water Resources website to learn more about the State Water Project.