The Sunnyvale East Channel is approximately 6.5 miles long and extends from the Guadalupe Slough to near Highway 280.
The Sunnyvale West Channel is approximately 3 miles long and extends from the Guadalupe Slough to Maude Avenue. The channels flow south to north draining predominately urban watershed areas which are located in portions of the Cities of Sunnyvale, Mountain View, Cupertino, and unincorporated Santa Clara County. The watersheds receive an average annual rainfall ranging from 17 inches in the headwaters to 12.5 inches near San Francisco Bay.
The Sunnyvale East and West Channels were constructed by the water district in the 1960’s and 1970’s to convey a 10-year storm from the storm drain systems of Sunnyvale and Cupertino 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.
Flooding can result in millions of dollars in damages to homes, businesses and schools. In addition, disruption to businesses and transportation networks can result in significant loss of productivity and revenue. The goal of the project is to provide protection to property, avoid transportation shutdowns and prevent potential damages that could exceed $33.6 million (1999 value) per event.
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 Santa Clara Valley Water District has completed the planning phase of this flood-protection project and is 60% complete with the design phase. The final design is targeted for completion in December 2013.