O'Neill Dam
Introduction '''O'Neill Dam''' is an earthfill dam on San Luis Creek,  west of Los Banos, California, United States, on the eastern slopes of the Pacific Coast Ranges of Merced County. Forming the O'Neill Forebay, a forebay to the San Luis Reservoir, it is roughly  downstream from the San Luis Dam.
Background Built from 1963 to 1967, the dam is an earthfill and rockfill construction stretching over  across the valley of San Luis Creek. A morning-glory type spillway lies at the left bank of the reservoir. At  high, with a maximum reservoir depth of , the crest of the dam is  long, at an elevation of . The spillway is, as mentioned before, a morning-glory (inverted bell) design, capacity  per second, and with a circumference of .
O'Neill Forebay reservoir The O'Neill Forebay reservoir is fed by releases from the San Luis Dam as well as from the Delta–Mendota Canal. Water from the Delta–Mendota Canal is lifted a vertical distance of  into a channel running  into the forebay. The peak inflow to the forebay is  per second, from both the San Luis Dam and the Delta–Mendota Canal. Drainage area of the reservoir downstream of the San Luis Dam is only .
O'Neill Pumping-Generating Plant The O'Neill Pumping-Generating Plant produces . Irregular water releases from the San Luis Dam and William R. Gianelli Powerplant are collected in the reservoir of the O'Neill Dam, which has a capacity of .
See also *List of dams and reservoirs in California
Notes
References *
External links *