In a significant development for California’s water management, plans for the Sites Reservoir in Northern California have been finalized. The reservoir, set to become the nation’s second-largest off-stream reservoir, will significantly increase NorCal’s water storage capacity by up to 15%, according to the Bureau of Reclamation.
Situated about an hour north of Sacramento, the project area lies between the Sacramento Valley to the east and the mountainous portion of the Coast Range to the west. Currently used for livestock and cattle grazing, the reservoir will serve primarily during dry periods and droughts, ensuring a more reliable water supply. The water would be diverted from the Sacramento Valley and held by a brand new Golden Gate Dam, roughly two times the size of Folsom Dam.
Originally designed to hold 1.9 million acre-feet of water, the project has now been scaled down to 1.5 million acre-feet following an economic feasibility review. To put this into perspective, Folsom Lake can store just under 1 million acre-feet, while Shasta Lake can hold over 4.5 million acre-feet.
The estimated cost of the Sites Reservoir project is now around $3.5 billion, with completion anticipated by 2030 or 2031. This endeavor represents a new approach to water management in the face of climate change, offering resilience against intensifying floods and droughts.
“This is a really big step forward for the Sites project and another example of how state and federal agencies are working together to build our water resilience amidst climate change,” said California Natural Resources Secretary Wade Crowfoot. “Sites Reservoir promises to help us adjust to intensifying floods and droughts by storing water in big, wet winters like we just had for use during the dry years that we know will return.”
Here’s a visual look at the project:
While the Sites Reservoir would contribute a small percentage to California’s overall water supply, it represents significant water resources for certain districts. The Metropolitan Water District, which delivers 1.6 million acre-feet of imported water to 19 million people annually, would receive an additional 50,000 acre-feet from Sites, a 3% increase. The Zone 7 Water Agency, serving 270,000 people in the East Bay, would see a 20% increase in supply with the addition of 10,000 acre-feet from Sites.