Sites Reservoir Project

As California’s climate shifts to longer dry periods punctuated by massive storm events and higher temperatures that will cause snowpack to melt more quickly, the state’s need for expanded water storage capacity becomes obvious.  The proposed Sites Reservoir in Colusa and Glenn Counties north of Sacramento will create just such a new supply, providing a reliable dry-year water supply for urban and rural water users alike.

Thirty water agencies from northern and southern California are participating in the project, with south-of-Delta agencies, including the Metropolitan Water District of Southern California, securing rights to a portion of the reservoir by committing to covering three-quarters of its cost.

Like the Metropolitan Water District’s Diamond Valley Reservoir in Southern California, Sites will be an off-stream reservoir, meaning that no major rivers will be dammed to create it, so many of the negative environmental impacts typically associated with new reservoirs are avoided.  When completed, it will be able to hold 1.5 million acre-feet of water, which is enough to serve 7.5 million people for a year.  Were it not for longstanding opposition from groups opposed to new water infrastructure, the Sites Reservoir could have been filled to capacity by precipitation that fell from the fall of 2022 to the spring of 2024 – but unfortunately all this water flowed to the ocean instead.

Current Status
Governor Newsom’s administration supports construction of the reservoir, and it has been certified under SB 149 to receive CEQA fast-tracking.  However, anti-growth environmental groups that have fought the proposal for decades are expected to maintain their opposition as their litigation against the project continues.