What is a State Water Project allocation?

The State Water Project (SWP) is a system of reservoirs, canals, and pumping plants that was built by the California Department of Water Resources (DWR) in the 1960s to provide water supply, flood control, wildlife habitat, and recreation. Water supplies from the SWP were always intended to fluctuate with California precipitation, which naturally swings between flood and drought. The SWP delivers water to 29 public water agencies based on long-term water supply contracts. Each year, starting in December, DWR announces to those water agencies – called SWP contractors – approximately how much water the project is likely to be capable of delivering in the coming year. Once a month for several more months, DWR assesses the water supply for “allocation” and may update the allocation if conditions warrant. The allocation is expressed as a percentage of the 29 public water agencies’ maximum water supply contract, such as 15 percent or 75 percent. DWR announces the final allocation in May or June, then make deliveries to contractors based on the final allocation and subsequent contractor demands. (more)