The Central Valley Project

Posted by: Aqua Blog Maven on August 19, 2008 at 4:15 pm

The Central Valley Project is California’s largest water supplier, delivering on average over 7 million acre-feet per year, mostly for agricultural use. The CVP irrigates 3 million acres of farmland in the San Joaquin Valley, as well as provides water for urban and industrial use in Contra Costa, Santa Clara, and Sacramento counties. The Central Valley Project is the largest of the Bureau of Reclamation’s 17 irrigation projects.

California is the nation’s leading agricultural producer, but it wasn’t always that way. The San Joaquin Valley in the mid 1800s was more of a seasonal marsh, flooding frequently. It is estimated that the valley once contained over 500,000 acres of permanent wetland habitat. It was also home to Tulare Lake, the largest freshwater lake in the Western U.S.

The Central Valley Project was Initially conceived by state engineers and approved by the state legislature in 1933. However, the state was unable to finance the project due to the depression, and the state asked the federal government to step in.

Construction of the Central Valley Project began in 1937, with the first deliveries to Contra Costa County in 1940. Construction continued into the 1990s, and today, the Central Valley Project consists of 20 dams and reservoirs with a storage capacity of 11 million acre-feet, 11 power plants, three fish hatcheries, and 500 miles of canals and aqueducts.

Shasta Dam is the CVP’s largest dam and reservoir, and is one of the largest dams in the world. Located 12 miles north of Redding, it can store 4.5 million acre-feet of Sacramento and Trinity River water. Water released from Shasta dam, flows downstream towards the Delta, providing for irrigation and municipal uses in Sacramento and the Bay Area.

Water moves through the Delta south towards the project’s pumps at the Delta’s southern edge near the town of Tracy. The C. W. “Bill” Jones Pumping Plant was completed in 1951 and is the main transfer point for CVP water. Located near the state-run Harvey O. Banks pumping plant, six pumps life water 197 feet into the Delta Mendota Canal, where it then travels south into the Central Valley.

Not all portions of the CVP use the Delta for conveying water. Friant Dam, 25 miles northeast of Fresno, intercepts the flows of the San Joaquin River, creating Millerton Lake. Water released from Friant Dam is used for irrigation in the eastern portion of the Central Valley.

Described once by the Supreme Court as ‘an imaginative engineering feat’, California Water II describes the project as such: “In short, the CVP turns part of the Trinity River around to supplement Sacramento River flows, turns part of the San Joaquin River around to supply areas south of the river, and fills in the middle with Sacramento River and Delta water. (California Water II, page 24)

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