Stretching from Contra Costa to Monterey, the South Bay region includes major cities such as San Jose, Oakland, Walnut Creek and San Mateo. Although some local streams and rivers have been developed to provide drinking water, much of the region’s surface water is imported from the Mokelumne, Tuolumne, Sacramento and Feather rivers. San Francisco’s Hetch Hetchy project supplies not only the city and county itself but also Hayward, San Jose and Palo Alto. Contra Costa County obtains its supplies directly from the Delta. The State Water Project’s South Bay Aqueduct supplies water to Alameda and Santa Clara counties. Groundwater is another major source of supply for the Santa Clara area, while farther south, such as in the city of Monterey, it is the only water source.