O'Neill Forebay

 lake, reservoir, aqueduct

The O'Neill Forebay is a balancing reservoir that receives water from the California Aqueduct and the Delta-Mendota Canal. Water can be pumped up into the San Luis Reservoir, conveyed southeast to farms and wildlife refuges in the DMC, or south to farms and to southern California for domestic uses in the San Luis Canal/California Aqueduct. The latter supplies more than 40 percent of the water supply for the Los Angeles area. Water in San Luis Reservoir can be released back into the O'Neill Forebay to generate electricity, or it can pumped westerly to Santa Clara County (Silicon Valley).
It is jointly operated by the California Department of Water Resources as part of the State Water Project and US Bureau of Reclamation as part of the Central Valley Project.
Local winds make this a fabulous place for wind-surfing.