O'Neill Forebay is a
forebay to the
San Luis Reservoir
The San Luis Reservoir is an artificial lake on San Luis Creek in the eastern slopes of the Diablo Range of Merced County, California, approximately west of Los Banos on State Route 152, which crosses Pacheco Pass and runs along its north ...
created by the construction of
O'Neill Dam across
San Luis Creek approximately west of
Los Banos, California
Los Banos ( ), alternatively Los Baños ( ), is a city in Merced County, California, United States. It is located in the San Joaquin Valley in central California, near the junction of State Route 152 and Interstate 5. Its population was 45,532 ...
,
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
, on the eastern slopes of the
Pacific Coast Ranges
The Pacific Coast Ranges (officially gazetted as the Pacific Mountain System in the United States) are the series of mountain ranges that stretch along the West Coast of North America from Alaska south to Northern and Central Mexico. Although the ...
of
Merced County
Merced County ( ), is a county located in the northern San Joaquin Valley section of the Central Valley, in the U.S. state of California.
As of the 2020 census, the population was 281,202. The county seat is Merced. The county is named after ...
.
Background
Roughly downstream from the
San Luis Dam
San Luis Dam is a major earth-filled dam in Merced County, California, which forms San Luis Reservoir, the largest off-stream reservoir in the United States. The dam and reservoir are located in the Diablo Range to the east of Pacheco Pass and ab ...
, O'Neill Forebay collects irregular water releases from the San Luis Dam and the 424 MW
pumped-storage hydroelectric
Pumped-storage hydroelectricity (PSH), or pumped hydroelectric energy storage (PHES), is a type of hydroelectric energy storage used by electric power systems for load balancing. The method stores energy in the form of gravitational potential ...
William R. Gianelli Powerplant in its basin. A
morning-glory type spillway lies at the
left bank
In geography, a bank is the land alongside a body of water. Different structures are referred to as ''banks'' in different fields of geography, as follows.
In limnology (the study of inland waters), a stream bank or river bank is the terrai ...
of the reservoir. The reservoir is fed by the
California Aqueduct
The Governor Edmund G. Brown California Aqueduct is a system of canals, tunnels, and pipelines that conveys water collected from the Sierra Nevada Mountains and valleys of Northern and Central California to Southern California. Named after Cali ...
and the
Delta–Mendota Canal
The Delta–Mendota Canal is a aqueduct in central California, United States. The canal was designed and completed in 1951 by the U.S. Bureau of Reclamation as part of the Central Valley Project. It carries freshwater to replace San Joaquin R ...
. Water from the canal is lifted a vertical distance of into a channel running into the forebay.
O'Neill Dam
O'Neill Dam, constructed from 1963 to 1967, is an , earthfill and rockfill dam, stretching over across the valley of San Luis Creek. With a maximum reservoir depth of , peak inflow to the forebay is per second, from both the San Luis Dam and the Delta–Mendota Canal. The drainage area of the reservoir downstream of the San Luis Dam is only . The O'Neill Pumping-Generating Plant stores 28 megawatts hours of energy.
[
]
Recreation
The California Office of Environmental Health Hazard Assessment
The Office of Environmental Health Hazard Assessment, commonly referred to as OEHHA (pronounced oh-EEE-ha), is a specialized department within the cabinet-level California Environmental Protection Agency ( CalEPA) with responsibility for evaluatin ...
(OEHHA) has developed an advisory for O'Neill Forebay because of mercury and PCBs found in fish caught here. The advisory provides safe eating advice for multiple fish species.
The largest striped bass
The striped bass (''Morone saxatilis''), also called the Atlantic striped bass, striper, linesider, rock, or rockfish, is an anadromous perciform fish of the family Moronidae found primarily along the Atlantic coast of North America. It has al ...
caught in California was caught in the O’Neill Forebay. The fish, and weighing , was caught on August 5, 2008, by Frank Ualat of Gilroy, California
Gilroy is a city in Northern California's Santa Clara County, south of Morgan Hill and north of San Benito County. Gilroy is the southernmost city in the San Francisco Bay Area, with a population of 56,766 as of the 2019 U.S. Census Projection ...
.
See also
*List of dams and reservoirs in California
Following is a list of dams and reservoirs in California in a sortable table. There are over 1,400 named dams and 1,300 named reservoirs in the state of California.
Dams in service
:''Please add to this list from the below sources.''
Former ...
*List of lakes in California
There are more than 3,000 named lakes, reservoirs, and dry lakes in the U.S. state of California.
Largest lakes
In terms of area covered, the largest lake in California is the Salton Sea, a lake formed in 1905 which is now saline. It occupies ...
References
*
External links
*
{{authority control
Reservoirs in Merced County, California
Central Valley Project
Reservoirs in California
Reservoirs in Northern California