California is looking for ways to optimize its water supplies while confronting opposing factors of increasing demand and decreasing availability. The past winter was a boon to parts of the state when storms dropped an estimated 32 trillion gallons of rainwater and up to seven feet of snow. Reservoirs throughout the state benefited from the influx and refilled, but significant quantities were lost, flowing as run-off to the ocean. The state’s water management plan currently includes 1,000 reservoirs that capture and store run-off with another one currently in the planning phase; however, there are contrasting assessments as to whether the actual benefits and the environmental impacts are worth the cost.

The Sites Reservoir project is an off-stream reservoir located in the western Sacramento Valley that has an estimated $4.4 billion price tag. The long-awaited infrastructure was first proposed in the 1980s as part of the State Water Project; more recent shortfalls in water supplies have renewed interest in the project. It is intended to capture and store up to 1.5 million acre-feet of water from the Sacramento River during periods of high runoff; during dry periods, it is expected to supply water to 24 million people and 500,000 acres of farmland in the Central Valley.[1]  Although Sites will have a limited impact on the state’s overall water supply, it will represent a significant influx for certain water districts, such as Zone 7 Water Agency which would see a 20 percent increase in supply.[2]

As an off-stream reservoir, it is anticipated to have fewer environmental impacts than those built on existing waterways; however, several environmental groups and tribes oppose the project arguing it would further degrade the Sacramento River and threaten native wildlife, including salmon. Further, the design of the project depends on intense storms to fill it while climate change has decreased the frequency and reliability of such precipitation, provoking skepticism. If storms don’t occur, the reservoir will remain empty wasting billions of tax-payer dollars.

If Sites had been operational, the storms in January would have delivered enough water to supply between 500,000 and one million households for a year, and for a state struggling with water supply, this is a significant loss.[3]  Sites Reservoir is currently in the planning phase addressing water rights, permitting and environmental review. Initially, the project was slated to break ground in 2024 but is more likely to do so in 2025 with completion expected in 2030 or 2031.

[1] Active NorCal. “Unlocking California’s $4.4 Billion Water Solution: When Will Sites Reservoir Finally Be Completed?” Active NorCal, 4 Apr. 2023, www.activenorcal.com/unlocking-californias-4-4-billion-water-solution-when-will-sites-reservoir-finally-be-completed/.

[2] Active NorCal. “Unlocking California’s $4.4 Billion Water Solution: When Will Sites Reservoir Finally Be Completed?” Active NorCal, 4 Apr. 2023, www.activenorcal.com/unlocking-californias-4-4-billion-water-solution-when-will-sites-reservoir-finally-be-completed/.

[3] Robins, Becki. “Will California Get Enough Rain to Fill Its Pricey New Reservoir?” Undark Magazine, 17 Apr. 2023, undark.org/2023/04/17/will-california-get-enough-rain-to-fill-its-pricey-new-reservoir/.