Press Release: New Analysis Finds Sites Reservoir Would Be 80 Percent Full After Recent Storms If It Were Operational Today

By Sarah February 15, 2024

New Analysis Finds Sites Reservoir Would Be 80 Percent Full After Recent Storms If It Were Operational Today

2023 and 2024 storms combined would have yielded 1.2 million acre-feet of water

SACRAMENTO, CA – The Sites Project Authority (Authority) announced that with the recent storms, Sites Reservoir could have diverted and captured 1.2 million acre-feet of water in 2023 and 2024 to date. Based on 2023 flows and significant storms this January and February, it is estimated that Sites Reservoir would be 80 percent full today following the critically dry prior years when Sites water would have been depleted.

“These latest storms show the need for Sites Reservoir to capitalize on California’s rainy season and store excess stormwater for the betterment of communities, farms, and the environment,” said Fritz Durst, Chairman of the Sites Project Authority Board of Directors. “While the exact amount of water will vary from year to year, we need to be prepared to capture water from major storms when they happen and save it for the next inevitable dry period. With hotter and drier weather threatening California’s water supply, we have no time to waste.”

Sites Reservoir is specifically designed to capture and store water generated by extreme storm events, like the atmospheric rivers that seasonally make landfall in California, to increase water flexibility, reliability, and resiliency in drier years.

The analysis found Sites Reservoir could have safely diverted a relatively small part of Delta outflow, leaving a significant natural flow in the Sacramento River and the Delta for ecosystem needs. Estimates show that during these most recent two months of 2024 storms and projecting diversions through mid-March, approximately 450 thousand acre-feet (TAF) could have been stored so far in 2024. There are still about two months of wet season remaining with the potential to raise water levels even more. A single acre-foot of water is enough to exceed the average annual indoor and outdoor water use of one to two California households, according to the Water Education Foundation.

This latest study shows that during major storms, and after all other needs being met, Sites Reservoir would be able to store excess water while meeting the project’s protective diversion criteria. This real time observation is consistent with the Authority’s robust water availability analyses, as presented in the Sites water right application currently being considered by the State Water Resources Control Board, where multiple analytical methods used predicted there is enough water for Sites, the environment, and existing senior water right holders in the Delta Watershed under a variety of water supply scenarios, now and in the future.

“The entire Sites team is invested in ensuring there will be water for Sites Reservoir while not harming the environment, which is why we conducted the most extensive water availability analysis in California history for this project,” said Jerry Brown, Executive Director of the Sites Project Authority. “The real-time data matches what the models are saying and demonstrates Sites can viably capture and store water for drier periods. We are confident in our analysis and are asking the State Water Resources Control Board to expeditiously come to the same conclusion and issue our water right permit, so we can get busy building this new, badly needed facility to provide more water certainty for all of California.”

Sites Reservoir is an off-stream reservoir that will capture and store a portion of stormwater from the Sacramento River—after all other water rights and regulatory requirements are met—and release water to California communities, farms, business, and wildlife during drier years. Sites Reservoir has broad statewide support from cities, counties, water agencies, and irrigation districts throughout the Sacramento Valley, San Joaquin Valley, Bay Area, and Southern California which are working together to advance the project. The Sites Reservoir Project is locally led by the Sites Project Authority, which is made up Sacramento Valley water districts, cities, and counties.

Sites is an off-stream reservoir proposed north of the Sacramento-San Joaquin Delta, where it would provide unique water supply and environmental benefits during dry periods, especially during extended drought. Additional information can be found at or on Facebook and Twitter at @SitesProject.

Download a PDF of this news release here.