SWP Benefits
The multipurpose State Water Project delivers water supply to its contracting agencies, provides flood control, generates power, enhances fish and wildlife habitat, power, releases freshwater flows to control salinity intrusion into the Delta, and offers a variety of recreational opportunities.

Water Supply
The SWP's main purpose is water supply--to divert and store surplus water during wet periods and distribute it to 29 public agencies which contract for SWP water supplies. Spring snowmelt runoff captured and stored in Oroville, together with unstored runoff available in the Delta, constitute its major sources.

Although designed to deliver 4.2 million acre-feet of water a year, the Project's existing facilities can typically supply only about 3 MAF. Their capacity to deliver full water supply requests in a given year depends of probabilities of rainfall, snowpack, runoff, water in storage, pumping capacity from the Delta, and regulatory constraints on SWP operations, especially in the Delta.

Of the contracted water supply, 70 percent goes to urban users and 30 percent to agricultural users. SWP water provides supplemental supplies to most of its contracting agencies’ local surface water, groundwater, and imported water sources.