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.