Back to top

E2: Sunnyvale East and Sunnyvale West Channels Flood Protection*

About This Project

This project is to upgrade approximately 6.4 miles of the existing Sunnyvale East Channel to provide 1% flood protection (100-year event) to 1,618 parcels and approximately three (3) miles of the existing West Channel to provide 1% flood protection for 47 acres of highly valuable industrial lands, including the Onizuka Air Force Base.

The Sunnyvale East Channel and Sunnyvale West Channel improvement projects have been combined into a single flood protection project with a single Environmental Impact Report (EIR) to reduce construction costs and improve efficiencies. Both projects decrease channel turbidity and sediment by repairing erosion sites, thereby improving water quality and reducing sediment to the San Francisco Bay.


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

Sunnyvale West Channel_looking south at Carl Road
Start FY 2022 / Finish FY 2027
Safe, Clean Water Fund ($23.1 million)
News and UpdatesNews and Updates
Reports and DocumentsReports and Documents
Environmental and Community BenefitsEnvironmental and Community Benefits
History and BackgroundHistory and Background
News & Updates

Project Modification: January 2023

On January 24, 2023, the Valley Water Board held a formal public hearing and approved reallocating construction-related planned expenditures for Sunnyvale East Channel. The modification was necessitated due to construction cost escalations across the Safe, Clean Water Program impacting the program’s financial health. This will impact Valley Water’s ability to construct the full project and deliver the KPI. Valley Water will reassess the availability of funding on an annual basis as part of the Capital Improvement Program’s financial planning process.

In FY23 (July 2022 – June 2023), Valley Water completed the 100% design documents.  Design documents will be final once the City of Sunnyvale and resource agency permits are incorporated. Valley Water resubmitted the regulatory permit applications in early-FY24 (August 2023). Depending on how long permit negotiations with the various resource agencies take, Valley Water hopes to receive the regulatory permits by mid-FY24. Upon receipt of the required permits, the project will be immediately advertised for construction (FY24), with anticipated completion in FY27. The project fact sheet is available.

On February 22, 2022, the Valley Water Board of Directors (Board) approved an agreement with Google for a design change along approximately 1,100 linear feet of the Sunnyvale West Channel as part of its proposed site development for the Google Caribbean Campus Project. In 2018, Valley Water entered a Memorandum of Understanding with Google to share costs associated with integrating flood conveyance improvements on the West Channel with Google’s campus development project. The Google project will create onsite and in-kind mitigation opportunities by constructing a wider channel with larger and taller setback levees without floodwalls. It will enhance public access and provide Valley Water the opportunity to utilize excess onsite and in-kind mitigation created by the Google project to offset some impacts from the Valley Water project. Valley Water has agreed to contribute $2.6 million towards the Google project. The amount represents estimated costs for incorporating the flood protection improvements designed by Valley Water within the Google project limits that Valley Water will no longer need to construct.

In addition to coordinating with Google on the West Sunnyvale Channel, Valley Water continues to collaborate with the City of Sunnyvale Water Pollution Control Plant (WPCP) on a perimeter wall around the city's facility at the downstream end of the Sunnyvale West Channel. Valley Water and the WPCP are finalizing the design of the wall to serve both as a flood protection barrier and a secure perimeter wall for the WPCP. Construction of the city's WPCP perimeter wall is scheduled to begin in 2023.

In February 2022, the Board approved the CEQA addendum, which addresses project changes resulting from the Google Caribbean Campus Project and the Valley Water–City of Sunnyvale Wastewater Pollution Control Plant joint, shared wall project.

In December 2020, an amendment to a cost-sharing agreement between Valley Water and the City of Sunnyvale to construct recreational trails was finalized, extending an original 2016 cost-sharing agreement to December 2025.

Valley Water submitted all the required permit applications to various state and federal regulatory agencies in June 2017. However, because portions of the project have been refined and five (5) years have transpired since permit applications were originally submitted, Valley Water resubmitted the regulatory permit applications in August 2023. Valley Water expects to receive the regulatory permits in mid-2024. Project construction is anticipated to begin in late-2024 and be completed by early-2027.

August 2023

For more information: 


Reports & Documents

Project Fact Sheets

Pursuant to the California Environmental Quality Act, the Santa Clara Valley Water District, as the lead agency for the proposed project, prepared a Draft Environmental Impact Report and a Final Environmental Impact Report to evaluate environmental impacts of the proposed flood protection project. Below is a summary of the environmental reports and documents. 

Final Environmental Impact Report

The Final EIR responds to public comment received on the Draft EIR during the public review period, as well as reflects changes to the Draft EIR made to address comments received during public circulation. The Final EIR was certified on September 9, 2014 by the District's Board of Directors.

Response Letters

Draft Environmental Impact Report 

The Draft EIR identified potentially significant environmental impacts associated with aesthetics, air quality, biological resources, cultural resources, geology/soils, greenhouse gas emissions, hazardous materials, hydrology/water resources, noise and vibration, land use, public utilities, recreation, and traffic. The majority of impacts were determined to be less than significant after the implementation of mitigation measures proposed. Construction impacts related to violation of applicable air quality and noise/vibration standards were determined to be significant and unavoidable even after implementation of air quality and vibration mitigation measures.

The Draft EIR was published and circulated between November 1, 2013 and December 15, 2013. The public review period was extended to February 21, 2014 to accommodate additional review time by the public agencies.

Environmental & Community Benefits

FY22-36 Key Performance Indicator for the Safe, Clean Water Program

  1. Provide 1% (100-year) flood protection for 1,618 properties and 47 acres (11 parcels) of industrial land, while improving stream water quality and working with other agencies to incorporate recreational opportunities.


  • Provides 1% flood capacity for approximately 6.4 miles of channel along Sunnyvale East and approximately three (3)
    miles of channel along Sunnyvale West within the City of Sunnyvale, protecting 1,618 properties (Sunnyvale East)
    and 47 acres (11 properties) of industrial land (Sunnyvale West)

  • Improves channel water quality by providing erosion control measures to decrease sediment and turbidity

  • Identifies recreational opportunities that can be integrated by the City of Sunnyvale and others as appropriate

  • Addresses climate change

Geographic Area of Benefit


    History & Background

    Flooding History and Project Background 

    The Sunnyvale East and West Channels were constructed by the Santa Clara Valley Water District in the 1960’s and 1970’s to alleviate the storm drain systems of Sunnyvale and Cupertino during a 10-year storm by directing the overflow through the channels to San Francisco Bay. Since construction of the channels, the project area has experienced flooding during major storm events in 1963, 1968, 1983, 1986 and 1998.

    Each winter, thousands of households, businesses and schools in Sunnyvale are susceptible to flooding from the Sunnyvale East and West channels during a major storm. The Sunnyvale East and West Channels were identified initially as separate projects in the Clean, Safe Creeks Plan approved by voters in November 2000. In order to improve efficiency, the two projects were combined and will move forward as a single effort. In November 2012, the project was transitioned to the Safe, Clean Water and Natural Flood Protection Program.

    In 2018, Valley Water entered into a Memorandum of Understanding with Google, LLC (Google) to incorporate Google’s proposed enhancement effort along 1,100 linear feet of the Sunnyvale West Channel into the project. This portion of the project will also be part of Google’s Caribbean Campus Project. Valley Water has completed 100% design and has submitted all required permit applications for the project. Once all permits are received, Valley Water will begin construction.

    About the Safe, Clean Water and Natural Flood Protection Program

    In November 2020, voters in Santa Clara County overwhelmingly approved Measure S, a renewal of Valley Water’s Safe, Clean Water and Natural Flood Protection Program.

    The program was first passed by voters in 2000 as the Clean, Safe Creeks and Natural Flood Protection Plan, then again in 2012 as the Safe, Clean Water and Natural Flood Protection Program. The renewal of the Safe, Clean Water Program will continue to provide approximately $47 million annually for local projects that deliver safe, clean water, natural flood protection, and environmental stewardship to all the communities we serve in Santa Clara County.

    While evaluating ways to improve the 2012 program, Valley Water gathered feedback from more than 21,000 community members. That helped Valley Water create the six priorities for the renewed Safe, Clean Water Program, which are:

    Priority A: Ensure a Safe, Reliable Water Supply

    Priority B: Reduce Toxins, Hazards and Contaminants in our Waterways

    Priority C: Protect our Water Supply and Dams from Earthquakes and Other Natural Disasters

    Priority D: Restore Wildlife Habitat and Provide Open Space

    Priority E: Provide Flood Protection to Homes, Businesses, Schools, Streets and Highways

    Priority F: Support Public Health and Public Safety for Our Community

    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. Additionally, the IMC also reviews each proposed 5-year implementation plan prior to its submittal for Board approval.

    In addition, the program requires three independent audits.

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