Upper Berryessa Creek Flood Protection*

Status

Completed

Location

Milpitas and San José

Schedule

Completed 2018

Funding

Safe, Clean Water Fund ($46.7 million); State of California; Department of Water Resources (Proposition 1E grant)

This project was done in partnership with the U.S. Army Corps of Engineers (USACE) to plan, design and construct flood improvements to protect homes in Milpitas and San José, as well as Silicon Valley’s commercial district, from a 1% (100-year) flood flow. The Bay Area Rapid Transit (BART) 10-mile extension project spans from Warm Springs Station in Fremont to the North San José Berryessa area. The new Milpitas Station is underground and is located in the Berryessa Creek floodplain. The completed Berryessa Creek project is critical to the operation and public use of the BART station.

*This project was voter approved as part of the Clean, Safe Creeks and Natural Flood Protection Plan.

In 2018, Valley Water and the United States Army Corps of Engineers (USACE) completed the Upper Berryessa Creek Flood Protection Project. The project extended along Berryessa Creek for approximately 2.2 miles, from I-680 downstream to Calaveras Boulevard. This area is now protected against a 100-year storm event. A 100-year storm event has a 1% chance of occurring in any given year (a 1 in 100 chance).

Valley Water and USACE developed a Floodplain Management Plan (FPMP). The purpose of the FPMP is to:

Document potential measures, practices, and policies that could reduce the impacts of future residual risks of flooding associated with the project, and
Help preserve flood protection levels provided by the project and enhance the natural values of the floodplain and creek.

The final FPMP is available for review.

June 2023: Valley Water provided the Post-Construction Stormwater Management Plan to the San Francisco Bay Regional Water Quality Control Board.

July 2023: Valley Water hired an environmental consultant to develop the Off-Site Mitigation Plan for the San Francisco Bay Regional Water Quality Control Board.

January 2024: The Pacific Gas and Electric utility located downstream of the Montague Expressway bridge was relocated.

January 2025: The San Francisco Bay Regional Water Quality Control Board issued a revised order for their Water Quality Certification permit that required additional mitigation planting increasing the planting acreage from 3 to 15 acres. In 2023, Valley Water and the Regional Board worked together to identify off-site areas for the additional mitigation planting. Valley Water is currently designing the mitigation planting sites and anticipates starting construction in February 2026. Plant installation will be performed during the rainy season in February-April 2026 and will take three to four years to complete by approximately March 2029. Following completion of the planting, maintenance and plant establishment work will continue until December 2030.

Valley Water and USACE are working to reconcile project costs and closeout the project by the end of 2026.

September 2025

For more information:

Karl Neuman, project manager, (408) 630-3059
Jose Villarreal, public information, (408) 630-2879
Sign up to receive project updates via email.

Upper Berryessa Creek looking downstream towards the Montague Expressway bridge along the widened earthen channel and new maintenance road.

Valley Water and USACE developed a Floodplain Management Plan (FPMP). The purpose of the FPMP is to:

Document potential measures, practices, and policies that could reduce the impacts of future residual risks of flooding associated with the project, and
Help preserve flood protection levels provided by the project and enhance the natural values of the floodplain and creek.

The final FPMP is available for review.

June 2023: Valley Water provided the Post-Construction Stormwater Management Plan to the San Francisco Bay Regional Water Quality Control Board.

July 2023: Valley Water hired an environmental consultant to develop the Off-Site Mitigation Plan for the San Francisco Bay Regional Water Quality Control Board.

January 2024: The Pacific Gas and Electric utility located downstream of the Montague Expressway bridge was relocated.

Valley Water and USACE are working to reconcile project costs and closeout the project by the end of 2026.

September 2025

For more information:

Karl Neuman, project manager, (408) 630-3059
Jose Villarreal, public information, (408) 630-2879
Sign up to receive project updates via email.

Upper Berryessa Creek looking downstream towards the Montague Expressway bridge along the widened earthen channel and new maintenance road.

Project Fact Sheets

Fact sheet

Meetings and Notices

Sept. 12, 2016 - Community meeting hosted by the U.S. Army Corps of Engineers and the Santa Clara Valley Water District.

Safe, Clean Water Program Documents

All annual reports, annual IMC audit reports and independent audits

Key Performance Indicators for the Safe, Clean Water Program

Local and federal flood damage reduction for 1,662 parcels including 1,420, 170 businesses, and 5 schools/institutions.
Using local funds only, a reduced project would extend from the confluence with Lower Penitencia upstream to Montague Expressway, modifying 2 miles of channel and protecting approximately 100 parcels.

Benefits

Protects up to 1,662 businesses and homes in Milpitas and San José from a 1% flood, saving potential damages in excess of $527 million
Provides protection for more than 30 miles of streets including Highway 237 and Montague Expressway

Geographic Area of Benefit

Milpitas and San José

Flooding History and Project Background

The Berryessa Creek Flood Risk Management Project encompasses approximately 2.2 miles of Berryessa Creek from Calaveras Boulevard to Interstate 680.

The Upper Berryessa Creek flood protection project offers a tremendous opportunity for a project to increase flood protection and stabilize the channel banks. Valley Water will continue to work with the community and cities to provide critical flood protection needs for Milpitas and San José.

Upper Berryessa Creek has a history of flooding, having experienced major events within the project area in 1982, 1983, and 1998. In 1982, the bank overflowed south of Calaveras Boulevard. To date, the creek has a 25 percent chance of flooding each year.

Flooding can result in millions of dollars in damage to homes, businesses, schools, and other infrastructure. Disruption to businesses and transportation networks such as the upcoming BART station at Montague Expressway will result in significant loss of productivity and revenue. One of the project’s goals is to avoid utility and transportation shutdowns and prevent potential damages from a 100-year storm event* exceeding $528 million (2011 value) per event. Approximately, 500 businesses and homes would be affected. The Santa Clara Valley Water District has initiated design of a flood protection project along 2.2 miles of the creek from Calaveras Boulevard to Interstate 680.

* A 100-year storm event, sometimes called a one-percent flood event, has a 1-in-100 chance of occurring in any given year.

About the Safe, Clean Water and Natural Flood Protection Program

In November 2012 the voters of Santa Clara County overwhelmingly approved Measure B, the Safe, Clean Water and Natural Flood Protection Program, as a countywide special parcel tax for 15 years with a sunset date of June 30, 2028. This Program replaced the Clean, Safe Creeks and Natural Flood Protection Plan, which voters approved in November 2000.

The Safe, Clean Water Program was developed with input from more than 16,000 residents and stakeholders and was created to match the community’s needs and values. The voters of Santa Clara County identified five priorities:

Priority A: Ensure a Safe, Reliable Water Supply
Priority B: Reduce Toxins, Hazards and Contaminants in our Waterways
Priority C: Protect our Water Supply from Earthquakes and Natural Disasters
Priority D: Restore Wildlife Habitat and Provide Open Space
Priority E: Provide Flood Protection to Homes, Businesses, Schools and Highways
Other: Six projects from the Clean, Safe, Creeks Plan have been carried forward into the Safe, Clean Water Program.

Each year, Valley Water prepares a report providing a progress update for each of these Program priorities, along with fiscal year accomplishments.

To ensure transparency and accountability to the voters, the ballot measure also created an Independent Monitoring Committee, appointed by the Santa Clara Valley Water District Board of Directors. The Independent Monitoring Committee annually reviews the Program’s progress to ensure the outcomes are achieved in a cost-efficient manner and reports its findings to the Board.

In addition, the Program requires three independent audits, the first of which was conducted in FY 2017.

View the Safe, Clean Water Program’s annual reports, annual IMC audit reports, and independent audits, including a staff response, on the District website.