Sites Reservoir is a proposed $5.2-billion offstream reservoir project west of Colusa in the Sacramento Valley of northern California, to be built by the California Department of Water Resources. The project would pump per year of the winter flood flow from the Sacramento River upstream of the Sacramento–San Joaquin River Delta, through existing canals to an artificial lake away. Annual yield will depend on precipitation and environmental restrictions. The California State Water Project would operate the $5.2-billion project. Estimated economic benefits are around $260 million per year, with an operating cost of $10–20 million. Preliminary studies were conducted at a cost of $50 million during 1996–2014. In 2018, the state awarded the reservoir project $820 million from a bond, half the funding originally sought. Project backers were displeased with the funding shortfall. Additional funding was tentatively pledged from water agencies in the Sacramento Valley, Fresno and urban agencies including Los Angeles. Each agency will be entitled to store water in the lake, in proportion to its share of the construction funding. In view of the shortfall, the pledges are being reassessed. The reservoir would be reduced in size if funding were cut back, but backers believe the project would still be built., construction was to begin in 2023 and be completed in 2030. The state will fund 16% or $820 million of the $5.2 billion project in exchange for rights to nine percent of the yield or per year, to protect habitat for endangered Delta smelt and for wildlife refuges.
History
The Sites Reservoir was proposed in the 1980s. California had serious droughts in 2006–2010 and 2011–2017, raising concern about water insecurity. The project is intended to improve reliability of supply during drought conditions.
Cost and funding
The estimated cost of the reservoir is $5.2 billion. In 2018, the state awarded $820 million from a bond to the reservoir project. About 30 water agencies in California have tentatively committed funding. The high cost of storage has led irrigation districts in the Sacramento Valley to reduce their funding and share of ownership. Water agencies in southern California and the San Joaquin Valley have increased their share. Crops grown in the San Joaquin Valley, such as pistachios and almonds, have a higher value than typical crops in the Sacramento Valley. The San Joaquin Valley and urban agencies can afford to acquire higher-cost water. However, by state law, agencies in the Sacramento Valley control the entire governing board for the project. The federal Bureau of Reclamation could put $1 billion into the project.
Specifications
The reservoir would be formed by several dams located in the east foothills of the California Coast Ranges, flooding the long and narrow Antelope Valley. The main dams, Sites and Golden Gate, would be built across Stone Corral and Funks Creeks, respectively. Six smaller saddle dikes would hold in the north end of the lake. The total capacity would be between. Capacity could be expanded in the future, by raising the surrounding dikes. The maximum inflow,, will be carried by the existing Tehama-Colusa and Glenn-Colusa Canals and a new pumping station on the Sacramento River near Red Bluff. The project is a pumped-storage hydroelectric plant, similar to San Luis Reservoir in the San Joaquin Valley, and would be a net power consumer; however, it would be able to generate peaking power. It will provide large-scale grid energy storage.
Environmental impacts
The proposed reservoir is not located on a major river but would affect salmon fisheries, because as part of California infrastructure to provide water to state agricultural interests it would impound water diverted from salmon-bearing watersheds, particularly the Trinity River via Lewiston Dam, with major negative impacts to imperiled salmon species already diminished by current and past water diversions to agriculture far from the sensitive watersheds of the north state. The state government's planning had not taken these impacts to threatened and endangered species into account as of early 2020. Diversions could take 60 percent of the Sacramento River's flow at times, potentially harming salmon and other fish. The reservoir itself would affect habitat for 23 sensitive, threatened or endangered wildlife species. Evaporation from the reservoir would remove per year. To protect fisheries, the pumping stations along the Sacramento River will have fish screens. There are potential modifications upstream at Shasta Dam that could increase the supply of cold water. The intakes at the Tehama-Colusa and Glenn-Colusa Canals will be modified. State regulators announced environmental restrictions in 2018 that would limit river withdrawals to protect fish, but environmental protections are under attack by the current federal administration and the state has not included strong protections in infrastructure plans. The water supply could fall short of projections.
