California's largest new reservoir in more than 50 years has cleared its last regulatory hurdle. The State Water Resources Control Board has approved the final water-right permit for Sites Reservoir, Governor Gavin Newsom announced on Thursday, November 5, ending decades of planning and clearing the way for construction of a 1.5 million acre-foot lake in the Sacramento Valley foothills of Glenn and Colusa counties.

Source: Office of the Governor of California

Sites is an off-stream reservoir: instead of damming a river, it will capture water from the Sacramento River during eligible high-flow periods — the big storms and wet winters when the river runs far beyond what farms and cities can use — and store it for the prolonged dry periods that follow. The reservoir site sits about 65 miles northwest of Sacramento, roughly 10 miles west of the town of Maxwell, and will use new and existing infrastructure to move water from the river near Red Bluff and Hamilton City into storage.

Source: California State Water Resources Control Board, via Maven's Notebook

How the permit works — and what it does not cover

Because Sites sits off the river rather than across it, the reservoir will not block fish migration or spawning, and the permit sets conditions for when and how much water can be diverted so that environmental protections for the Sacramento River are built into the project, the Water Board said. This week's approval covers diversions from the Sacramento River only. 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.

California Secretary for Natural Resources Wade Crowfoot said: "Our water system was built for a climate that no longer exists. To adapt, we need to capture water during huge storms and wet winters to get us through worsening droughts — and that's exactly what Sites Reservoir will do. All regulatory approvals have now been provided and California is on the verge of breaking ground on this critical investment for our communities, economy, and environment." Once complete, the Governor's office says, Sites will also provide flood-management benefits by capturing storm flows, deliver water to wildlife refuges including the Sacramento National Wildlife Refuge Complex, the Upper Butte Basin Wildlife Area and the San Luis National Wildlife Refuge, hold up to 200,000 acre-feet for use during emergency-declared droughts, and create recreation for an estimated 187,000 visitors a year.

Background: decades in the making, the biggest build since 1979

Sites has been studied and debated for decades, and it would be the largest new reservoir built in California since the federal government opened New Melones Lake in 1979 — the state's eighth-largest reservoir when finished. The project has drawn support across party lines: the federal Bureau of Reclamation issued its record of decision approving the environmental review in January 2026, an earlier federal loan commitment of $2.2 billion dates from 2022, and cost estimates reported earlier this year put the build at roughly $6.2 to $6.8 billion. In Sacramento, Newsom signed the SB 149 infrastructure-streamlining law in 2023 and used it to fast-track Sites, which then defeated a CEQA environmental challenge in court. In June 2026 the Governor announced nearly $269 million in additional funding, bringing total eligible state funding to approximately $1.36 billion.

Source: Mercury News reporting, via Phys.org (January 2026 background)

Why this matters: water is the Central Valley's economy

State projections cited by the Governor's office say California could lose 10 percent of its water supply by 2040 as hotter, drier conditions shrink the mountain snowpack, while the reliability of the State Water Project could decline by as much as 23 percent. For the Sacramento and San Joaquin valleys — where Punjabi and other immigrant families farm almonds, peaches, rice and vegetables, run trucking fleets that haul the harvest, and staff the packing houses and cold stores along Highway 99 and Interstate 5 — water reliability is not an abstraction: it decides what gets planted, what gets harvested and what gets hauled. A reservoir designed to bank wet-year water for dry years is aimed squarely at that cycle, and supporters from the Bay Area Council to Southern California water agencies argue the benefits run the length of the state, while the permit's diversion conditions are the state's attempt to balance those supplies against the river's fish and water quality.

What happens next

With the water right approved, the Governor's office says the project has cleared all regulatory approvals needed to initiate construction. The Sites Project Authority and its participating water agencies now turn to advancing the financing needed to begin building; Bay Area Council president Libby Schaaf, a supporter, said California is "prepared to break ground next year on the largest reservoir built in the state in generations." Two dates frame the next phase: the separate Water Board hearing on Funks and Stone Corral creeks opens in January 2027, and earlier project schedules reported this year pointed to construction running toward completion around 2033. Fritz Durst, chair of the Sites Project Authority Board of Directors, said: "Sites has been decades in the making, and we are closer than ever to making it a reality. With this decision, we're ready to move forward and turn years of planning into action."