The Sites Project Authority released findings Wednesday from a new analysis that projected Sites Reservoir could have diverted and captured 120,000 acre-feet of water in just two weeks if the reservoir had been operational from Jan. 3 through Jan. 15 and would continue to capture water over the next few weeks as flows continue to run high.
“This is exactly the type of scenario that Sites is being built for – short windows of extremely high flows. There is an untapped opportunity to capture and store a portion of the significant amount of flow from the Sacramento River that occurs during these rare but major storms without impacting the value of these high flows for our environment,” said Jerry Brown, executive director of the Sites Project Authority.
The project, which has been in the works for more than 60 years, hopes to turn the Sites Valley, located 10 miles west of Maxwell where Colusa and Glenn counties meet, into a state-of-the-art off-stream water storage facility that captures and stores stormwater flows in the Sacramento River – after all other water rights and regulatory requirements are met – for release in dry and critical years for environmental use and for communities, farms and businesses statewide to utilize when needed.
According to a release issued by the Authority, the analysis found Sites Reservoir could have diverted 120,000 acre-feet of water – less than 4% of Delta outflow – from Jan. 3 to Jan. 15 and long-range forecasts estimated that Sites Reservoir would continue to divert stormwater through at least Feb. 15, for a total 382,000 acre-feet of water.
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.
“The rainstorms that pummeled Northern California would have been Sites’ time to shine,” said Alicia Forsythe, environmental planning and permitting manager of the Sites Project Authority. “It would have captured a portion of the flood waters for use in future dry times by farms, families, and ecosystems, while leaving lots of water in the Sacramento River and Delta for our environment and fisheries.”
Project officials said that while recent storms caused Sacramento River flows to increase in late December, the Project would have implemented its seven-day pulse flow protection criteria and not started diverting until Jan. 3.
“The pulse flow protection criteria protects these initial high flow events as they provide value for outmigrating salmon and our river ecosystems,” the release said. “Periods of heavy rainfall are ideal opportunities to divert and capture water that accumulates quickly but is often lost to flooding and rapid runoff. Sites will not divert any water until all other water rights and regulatory requirements are met. The analysis shows that during these major storms, all these other needs can be met, and Sites would still be able to store excess water while meeting the project’s protective diversion criteria.”
The Sites Reservoir Project is locally led by the Sites Project Authority which is made up of 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,” officials said.
