Massive Surface Water Projects Built to Transport Water from North to South

The toll of groundwater overdraft was instrumental in leading the federal government and the state of California to build two mammoth aqueduct projects – the Central Valley Project and the State Water Project. These brought surface water from the mountains, through the Sacramento-San Joaquin Delta, and on to the Central Valley and points far south – over 700 miles of canals and pipelines.

Average Use (2005-2010)
Million Acre‑Feet
Surface Water
Central Valley Project
State Water Project
Additional Information
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Average Groundwater Usage
Based on average annual data for years 2005 to 2010, groundwater use was near 16.5 million acre feet and accounted for about 39 percent of the total water supply in California.
Source: DWR Groundwater Report
State Water Project
The SWP’s 20 major reservoirs can hold 5.8 million acre-feet, with annual deliveries averaging up to 3 million acre-feet.
SWP deliveries are 70 percent urban and 30 percent agriculture, meeting the needs of 20 million Californians and more than 600,000 irrigated acres, respectively.
Central Valley Project
The CVP's 22 reservoirs have a combined storage of 11 million acre-feet, of which 7 million acre-feet is delivered in an average year. CVP water irrigates more than 3 million acres of farmland and provides drinking water to nearly 2 million consumers.
Agricultural Areas Reservoirs Major Rivers

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A series of articles exploring the use and management of California’s precious resource.