Project location:
Sunnyvale East Channel is approximately 6 miles long and extends from Guadalupe Slough to near Highway 280.
Sunnyvale West Channel is approximately 3 miles longs and extends from the Guadalupe Slough to Maude Avenue. The channels flow south to north draining predominately urban watershed areas which includes portions 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.
Flooding history:
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 Sunnyvale East and West channels during a major storm. The Santa Clara Valley Water District has initiated planning of this flood-protection project along the approximately three miles of Sunnyvale West Channel from just upstream of U.S. 101 to Guadalupe Slough, and the approximately six miles of Sunnyvale East Channel from Interstate 280 to Guadalupe Slough.