A collaboration between Valley Water, the San Benito County Water District and the Pacheco Pass Water District, the Pacheco Reservoir Expansion Project is a strategic and long-term investment toward ensuring a more reliable supply of safe, clean drinking water in the face of climate change.
The project will boost Pacheco Reservoir’s operational capacity from 5,500 acre-feet to up to 140,000 acre-feet, enough to supply up to 1.4 million residents with water for one year in an emergency. The project will also reduce the frequency and severity of water shortages during droughts, protect our drinking water supply and infrastructure, and improve habitat for fish.
- (01/31/2020 update) Expanding Pacheco Reservoir will ensure a more reliable supply of safe, clean drinking water for our region.
- (Jan 2020 update) Valley Water is now offering free half-day bus tours to some of our water infrastructure facilities. To learn more about upcoming tour dates and sign up, please visit our public tours webpage.
Water is our most precious resource. Climate change, droughts, and population growth pose significant challenges for the reliability of our water supply. Preparing for future dry years by ensuring a reliable supply of safe, clean drinking water is vital for the region. The Pacheco Project will help us provide a more reliable supply for you and your family.
Join the growing list of supporters
Join our efforts to bring this project to fruition. There is much to like in the Pacheco Reservoir Expansion Project as it delivers on the promises that earned a “Yes” vote for Prop. 1 by nearly three of every four San Benito and Santa Clara county voters in 2014.
Be a part of the 62 environmental, community, non-profit and businesses organizations, along with elected leaders, who have submitted letters supporting the project. Please join this wide-ranging group of supporters.
We are committed to keeping you informed with our progress and to provide opportunities for your input on this project. Please sign up for progress updates.
- Pacheco Reservoir Expansion Project Brochure (September 2020)
- Pacheco Reservoir Project - Public Benefits Fact Sheet August 2019
- Pacheco Reservoir Expansion Project - Information Sheet March 2019
- Pacheco Reservoir Expansion Project Water Commission presentation Dec 2017
- Pacheco Reservoir Expansion Project - Public Benefits Fact Sheet 2018
- Frequently Asked Question on the Pacheco Reservoir Expansion Project (updated April 2018)
- Notice of Preparation and Initial Study (2017)
Ensuring a more reliable supply of safe, clean drinking water
Safe and Clean Drinking Water – Emergency Water Supply – Improving Habitat for Fish – Flood Risk Reduction
A collaboration between Valley Water, the Pacheco Pass Water District and the San Benito County Water District, the Pacheco Reservoir Expansion Project is a strategic and long-term investment toward building a more reliable water supply in the face of climate change. The increased storage capacity at Pacheco Reservoir will nearly equal the capacity of Valley Water’s ten other reservoirs combined.
The project will also reduce the frequency and severity of water shortages during droughts, protect our drinking water supply and infrastructure, and improve habitat for fish. The Pacheco Project has also been named as the preliminary preferred option to address an issue of algae growth at San Luis Reservoir. Read more about the connection between the Pacheco Project and San Luis Reservoir here.
What does an expanded Pacheco Reservoir mean to us?
In Santa Clara and San Benito counties, about 40% of our water supply currently comes from the Sacramento-San Joaquin Delta. In the event of an earthquake, Delta levee failure or other major catastrophe, we could lose that water for up to 18 months. The project will boost Pacheco Reservoir’s operational capacity from 5,500 acre-feet to up to 140,000 acre-feet, enough to supply up to 1.4 million residents for one year in an emergency.
In Santa Clara County, nearly half of all our water is pumped from underground basins.
During droughts and emergencies, there is a greater reliance on these aquifers, but overpumping groundwater could result in subsidence (the sinking of earth’s surface), which causes permanent damage to roads, bridges and pipelines. Expanding Pacheco Reservoir would double the amount of water we can store above ground, making us less reliant on our groundwater supply during droughts, which would replenish the groundwater supply and protect overlying infrastructure.
By expanding Pacheco Reservoir, managed water flows from the reservoir into Pacheco Creek would increase the quality of fish habitat downstream. The expanded reservoir would provide suitable flow and water temperatures to Pacheco Creek and improve approximately 10 miles of habitat to support the migration and survival of the South Central California Coast Steelhead.
The expanded Pacheco Reservoir will incidentally reduce flood risk along Pacheco Creek and downstream Pajaro River by holding back peak flows, offering some relief to disadvantaged communities in Dunneville, Watsonville and Pajaro.
About Pacheco Reservoir
Located on the lower end of North Fork Pacheco Creek, the expanded reservoir project includes the construction of an earthen dam made of rock and soil upstream of the existing dam, a pump station, a pipeline and other supporting items. The expanded reservoir would be filled by a combination of rainfall, runoff from the watershed upstream of the new dam, and imported water supplies.
Water released from the reservoir will help threatened fish by keeping the Pacheco Creek flowing, before seeping into the underlying groundwater aquifer as it winds toward where it meets the Pajaro River.
The aquifer fed by Pacheco Reservoir begins at its northern tip in Santa Clara County and extends south into San Benito County. Agricultural users served by the Pacheco Pass and San Benito County water districts pump water from this aquifer.
Funding the project
In 2017, Valley Water, Pacheco Pass Water District and the San Benito County Water District collaborated in securing $484.5 million of the $1 billion project cost to increase Pacheco Reservoir's storage capacity and deliver water supply, water quality and ecosystems benefits to the region and the Sacramento-San Joaquin Delta. Funding to expand Pacheco Reservoir, located 60 miles southeast of San Jose, was secured from California’s Water Quality, Supply and Infrastructure Improvement Act of 2014. The Act, passed by state voters as Proposition 1, provided $2.7 billion for investments in surface and groundwater storage projects, under the Act’s Water Storage Investment Program.
Currently, Valley Water has entered into an early funding agreement for $24.2 million with the California Water Commission to share project planning and environmental studies costs. Valley Water is presently conducting studies, investigations and surveys to design and evaluate potential environmental impacts and feasibility. The draft environmental impact report is expected to be released by 2022.
Staff is available to provide presentations to civic, neighborhood, and stakeholder groups. To request a presentation, please contact: Mark Gomez, [email protected], or (408) 630-2985. You may also review the project’s frequently asked questions to learn more about the benefits.
Updated: February 2020