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Sunnyvale East and West Channels Flood Protection*

About This Project

In the early stages of the project design process, Valley Water project team decided to join both improvement projects into a single flood protection project with a single Environmental Impact Report (EIR) to reduce construction costs and minimize construction coordination issues between the 2 channels.

The West Channel extends approximately 3 miles and upgrades existing channel capacity to provide 1% (or 100-year) riverine flood protection for 47 acres of highly valuable industrial lands, including the Onizuka Air Force Base. The East Channel extends approximately 6.4 miles and upgrades existing channel capacity to provide 1% riverine flood protection for 1,618 parcels. Both projects decrease channel turbidity and sediment by repairing erosion sites, thereby improving water quality.


*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 2007/ Finish FY 2023
Safe, Clean Water Fund ($60.0 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

One-hundred percent design is on-going and is expected to be completed in the fall of 2019.

To date, 5 permanent rights-of-way acquisitions, all necessary for project construction, have been acquired. Valley Water is working to acquire final leasing agreements, as well as temporary construction easements from Santa Clara County and San Francisco Public Utilities Commission (SFPUC). All acquisitions are anticipated to be final by December 2019.

In June 2017, Valley Water submitted all the required permit applications from the various state and federal regulatory agencies. The permit process is currently ongoing and anticipated to be received by spring 2020. Project construction is anticipated to begin in summer 2020 and to be completed by December 2022.

In October 2017, Valley Water was approached by Google, LLC with a proposal to partner on an enhancement project along 1,100 linear feet of the Sunnyvale West Channel (Caribbean Drive upstream to Caspian Court) in association with their proposed development project. Valley Water staff and Google representatives developed a Memorandum of Understanding (MOU), which the Valley Water’s Board of Directors approved in April 2018. Valley Water entered into this MOU partnership to enhance existing public infrastructure, explore on-site mitigation opportunities with Google, thereby possibly accelerating receipt of the required regulatory permits, while maintaining the project objectives for the Sunnyvale East and West Channels Flood Protection Project.

Google LLC, with the City of Sunnyvale as the lead California Environmental Quality Act (CEQA) agency, are expected to complete their final CEQA documents by December 2019 for their proposed development including the West Channel Enhancement Project. Once the Google’s CEQA documents are certified, Valley Water and Google will enter into a cost sharing agreement for Google’s West Channel Enhancement project, where Valley Water financial contribution will be based on Valley Water’s cost to construct their proposed prior flood protection improvements for this 1,100 linear foot section of the existing Sunnyvale West Channel.

Updated August 2019

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

Key Performance Indicator for the Safe, Clean Water Program 

  1. Provide riverine flood protection for 1,618 properties and 47 acres (11 parcels) of industrial land, while improving stream water quality and providing for recreational opportunities. 


  • Provides 1% flood capacity for approximately 6.5 miles of channel along Sunnyvale East and approximately 3 mile 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 stream water quality, by providing erosion control measures to decrease sediment and turbidity

  • Identifies opportunities to integrate recreation improvements with the City of Sunnyvale and others as appropriate 

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.

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 Valley Water website.