California Construction News staff writer
California has approved a final water rights permit for the proposed Sites Reservoir, moving the project closer to construction while setting limits on when and under what conditions water can be diverted from the Sacramento River.
The State Water Resources Control Board’s approval covers diversions from the Sacramento River only. Whether the project can also capture water from Funks and Stone Corral creeks, two local streams at the reservoir site, will be considered in a separate hearing beginning in January 2027.
Located in Glenn and Colusa counties, Sites Reservoir is designed to capture water during high-flow periods and store it for use during prolonged dry conditions. The project would add 1.5 million acre-feet of water storage capacity, making it California’s largest new reservoir in more than 50 years.
Under the permit conditions, water can only be diverted between November and mid-June, and only when supplies are surplus to the needs of senior water rights holders, Delta water quality requirements and fish.
The project must also comply with water quality protections under the recently updated Bay-Delta Plan. Initially, this means the reservoir will be subject to unimpaired flow requirements established through the regulatory pathway.
State Water Resources Control Board Chair E. Joaquin Esquivel said the updated plan provides a framework for balancing environmental protections with the development of additional water supplies.
“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.”
California Gov. Gavin Newsom said the approval marks a major step in the state’s efforts to address long-term water storage needs following decades without construction of a comparable project.
“From 2020 to 2022, California went through its driest three-year period on record, followed by nine atmospheric rivers in just three weeks,” Newsom said. “That’s the reality we’re up against.”
California Secretary for Natural Resources Wade Crowfoot said the state’s existing water infrastructure was designed for climate conditions that have changed.
“Our water system was built for a climate that no longer exists,” Crowfoot said. “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.”
Because the proposed reservoir is located off the Sacramento River, it is designed to avoid blocking fish migration or spawning.
Once complete, Sites Reservoir is expected to provide water to wildlife refuges, including the Sacramento National Wildlife Refuge Complex, Upper Butte Basin Wildlife Area and San Luis National Wildlife Refuge. It would also provide up to 200,000 acre-feet of water during emergency-declared droughts.
The project is expected to create recreational opportunities for an estimated 187,000 visitors annually.
Preparing for changing water conditions
California’s water supplies face increasing pressure from rising temperatures, declining mountain snowpack and more pronounced swings between drought and flooding.
State projections indicate California could lose 10 per cent of its water supply by 2040 because of hotter and drier conditions. The reliability of the State Water Project could decline by as much as 23 per cent.
The challenges are outlined in the State Water Project Adaptation Strategy, which identifies measures to protect the state’s long-term water supplies.
The Sacramento River permit approval clears one regulatory hurdle for Sites Reservoir, while the separate proceedings on diversions from Funks and Stone Corral creeks remain to be completed.
