State Water Board approves water right for Sites Reservoir

SACRAMENTO – As California responds to a changing climate, more extreme droughts and floods, and a growing need to store water during wet periods, the State Water Resources Control Board today approved a water right for a new reservoir that incorporates critical environmental safeguards to protect the state’s largest river.

The Sites Reservoir Project, located about 65 miles northwest of Sacramento, is an off-stream storage project that would divert water from the Sacramento River during relatively high flows and store it for farms, cities and the environment. Sites will use new and existing infrastructure to transfer water from the river near Red Bluff and Hamilton City to a new reservoir 10 miles west of the town of Maxwell.

The water right permit for the reservoir, which would be the largest surface water storage infrastructure built in California in more than 50 years, allows diversions of up to 986,000 acre-feet per year, or enough to supply about 8.4 million people annually.

Today's approval only covers diversions from the Sacramento River. Whether the project may also capture water from Funks and Stone Corral creeks, two local streams at the reservoir site, will be decided in a separate hearing that begins in January 2027.

Among the permit conditions, the project can only divert between November and mid-June, and when water is surplus to the needs of senior water right holders, Delta water quality and fish. It also must comply with water quality protections in the newly updated Bay-Delta Plan, which initially defaults the project to unimpaired flow requirements established by the regulatory pathway.

"With the adoption of last week's Bay-Delta Plan update, the State Water Board has established a durable framework that enables projects like Sites to be operated in a way that is protective of important river systems but flexible enough for the development of new water supplies critical to California's ability to adapt to hydrologic fluctuations brought on by climate change," said Chair E. Joaquin Esquivel. "Climate change is here, and we must lean into new ways of managing water to adapt to it. Expanding opportunities to increase supplies through storage makes sense, with robust environmental protections in place."

In addition to complying with the Bay-Delta Plan, the permit includes the following environmentally protective measures:

• Bypass flow requirements to ensure water is diverted only during relatively high flows.
• Restrictions on diversions during periods of fish migration.
• Authorization for a portion of the stored water to be used for wildlife refuges.
• The use of screens that prevent fish from being drawn into diversion facilities.
• New studies to confirm that minimum bypass flow requirements will prevent unreasonable harm to fish.
• Water quality requirements on reservoir releases to protect the river and Delta from harmful algal blooms, high temperatures and elevated mercury levels.

Once completed, the project will deliver water from the reservoir through canals or the river system to Sites proponents, which include state and federal agencies, public irrigation districts in the Sacramento and San Joaquin Valleys and urban water suppliers serving the Bay Area and Southern California.

Today's decision is the culmination of proceedings conducted by the board's Administrative Hearings Office, an independent unit created in 2019 to conduct neutral, fair and efficient evidentiary hearings on water rights matters. The hearings took place on 32 separate days over two years and involved 41 parties, 60 witnesses and over 2,100 evidentiary documents.

Staff with the hearings office prepared the draft decision and draft water right permit at the direction of the board, whose members were involved throughout the process. The board adopted the final decision after two public comment periods on drafts released in March and September.

More information about the Sites Reservoir water right application and hearing process can be found on the board's website.

The State Water Board's mission is to preserve, enhance and restore the quality of California's water resources and drinking water for the protection of the environment, public health and all beneficial uses, and to ensure proper resource allocation and efficient use for present and future generations.