The Sites Project Authority has advanced California’s proposed Sites Reservoir into an investment period following revisions to the project’s draft water right permit, moving the $6.2 billion-plus project closer to construction. The State Water Resources Control Board is expected to consider the final permit Nov. 4.

The proposed off-stream reservoir west of Maxwell in the Sacramento Valley would have a storage capacity of approximately 1.5 million acre-feet. The project is designed to capture water from the Sacramento River and local creeks during high-flow periods for later use during dry conditions.

The revised draft permit includes changes to the conditions governing when the project can divert Sacramento River water. According to the Sites Project Authority, the revisions allow the project to divert during high-flow conditions while maintaining protections for fish, wildlife and the Sacramento River and Delta. The Authority said the revised terms could support a viable project.

Once operational, Sites Reservoir is expected to provide up to 200,000 acre-feet of captured water for use during emergency-declared droughts. The project would also provide water to wildlife refuges and provide flood-control and recreation benefits.

The California Water Commission currently estimates total project costs at $6.2 billion to $6.8 billion, with the project conditionally eligible for approximately $1.363 billion in Water Storage Investment Program funding. The commission's current schedule anticipates water-right and other permitting approvals in 2026, with construction and commissioning extending into the 2030s.

The Sites Project Authority has also begun moving toward construction contracting, including its selection process for a construction manager at risk for the reservoir and roads portion of the project.