By Jessica Bies
Encompassing 35 counties, California’s Central Valley Project provides electrical power and water to farms, homes, and factories located within a 500-mile north-south stretch.
One of the largest water conservation developments in the U.S., it was constructed to protect the Central Valley Basin from water shortages and floods. Approved by President Roosevelt in 1935, the project continued through the 1940s and ’50s and eventually grew to involve various federal and state government agencies but was headed by the Bureau of Reclamation, a branch of the U.S. Department of the Interior.
The era of large dam building had waned by the 1960s and during the next several decades the Central Valley Project would become the focus of numerous political and environmental debates. By 1969, the chinook salmon and steelhead trout populations began to decline, prompting environmentalists and anglers to seek widespread change.
In 1992, the Central Valley Project Improvement Act was passed, reallocating 800,000 acre-feet of water from farmers for the restoration of Central Valley fisheries, despite strong objections from local politicians. About the same time, the National Marine Fisheries Service imposed a 12 C (54 F) maximum temperature limit on the upper Sacramento River.
One of the biggest threats facing chinook salmon is loss of habitat. While an estimated 16 million salmon populated U.S. waters before human settlement, today less than 2% of salmon have survived. While many fingers point to the U.S. government’s excessive utilization of hydroelectric and irrigation programs, today’s developments in dam design and management plus innovations such geosynthetic materials can mitigate these effects.