What is the Pacheco Reservoir Expansion Project?
The project is a collaboration between Valley Water, the San Benito County Water District and the Pacheco Pass Water District to expand Pacheco Reservoir in southeastern Santa Clara County. The proposed project would increase the reservoir’s capacity from 5,500 acre-feet to up to 140,000 acre-feet, enough water to supply 1.4 million residents for one year during an emergency.
How does this project improve our future water supply needs?
An expanded Pacheco Reservoir would allow us to hold water during wet years to use during droughts. The enlarged reservoir will capture more runoff from the North Fork Pacheco Creek watershed than the existing reservoir does today. It will also provide storage for some of the Central Valley Project water that is supplied by the Bureau of Reclamation to the San Benito County Water District and Valley Water. That water is fed from San Luis Reservoir, which holds water from the state and federal government, that lies at a higher elevation to the east.
The Pacheco Reservoir Expansion Project also enables a lower cost storage for dry years through purchase of water from the state and federal government during wet years.
How will Valley Water fill the reservoir during a drought? Will climate change impact our ability to fill the reservoir if we are expected to see more rapid snowmelt?
Weather is expected to be more extreme because of climate change, including more frequent and severe droughts with warmer spring rainstorms resulting in less snowpack (for early to mid-summer supplies) and more winter snowmelt in the Sierra Nevada.
Climate change models suggest more water will be available but at much shorter windows to pump from the Delta. This is exactly the scenario a reservoir such as Pacheco is needed. We can fill the reservoir at times when excess flow at the Delta is available for delivery to us. That gives us the ability to store it locally and use during the dry months. When we applied for funding through California’s Water Storage Investment Program, we researched the impacts of climate change forecasted out to 2030 and 2070 to make sure the reservoir is not only viable now, but also in the future.
Will recreation be allowed at the new reservoir?
Valley Water is discussing with other government agencies who handle recreation to see if they would partner with us. Adding this in would require some more work on the environmental impacts. We’ll continue to discuss plans for public access and recreation as we move forward with the project and give the public, landowners, non-profits, and other agencies more opportunities to speak out at upcoming meetings about what they want.