Sites Project Authority says reservoir could have captured 168,000 acre-feet during recent storms

The Sites Project Authority says recent atmospheric river events underscore the potential value of the proposed Sites Reservoir, estimating the project could have captured more than 168,000 acre-feet of water between late December 2025 and the end of January 2026 if it were operational.

According to the authority’s analysis, the estimate is based on actual Sacramento River flows and supports the project’s ability to capture excess water during wet periods for use in dry years. The authority noted that Sites Reservoir has already demonstrated strong performance potential, with analyses showing it could have diverted about 1.35 million acre-feet of water during the 2024 and 2025 diversion seasons.

“Weather events like this highlight the critical role Sites Reservoir could play during wet years by capturing excess water when it is available and holding it for the dry times ahead,” said Fritz Durst, chair of the Sites Project Authority Board of Directors, in a press release. “As California faces increasingly intense storms, expanding our water storage capacity is essential to ensure reliability during dry times, which is why the Sites Project continues to move forward.”

The authority emphasized that issuance of a water right order from the State Water Resources Control Board remains the key approval needed to advance construction. Continued delays in issuing the order are increasing project costs by an estimated $20 million per month, the authority said.

Sites Reservoir is designed as an off-stream storage project that would divert water from the Sacramento River during high-flow periods. The authority added that a single acre-foot of water can exceed the average annual indoor and outdoor use of two to three California households, highlighting the potential drinking water and supply reliability benefits of large-scale storage.