San Luis Reservoir
Encyclopedia
The San Luis Reservoir is an off-stream
artificial lake in the eastern slopes of the Diablo Range
of Merced County, California
, approximately 12 mi (19.3 km) west of Los Banos
on State Route 152
, which crosses Pacheco Pass
and runs along its north shore. The reservoir stores water taken from the San Joaquin-Sacramento River Delta as the surplus water would otherwise run into the Pacific Ocean
. Water is pumped uphill into the reservoir from the O'Neill Forebay
which is fed by the California Aqueduct
and is released back into the forebay to continue downstream along the aqueduct as needed for farm irrigation and other uses. Depending on water levels, the reservoir is approximately nine miles long from north to south at its longest point, and five miles (8 km) wide. At the eastern end of the reservoir is the San Luis Dam
, or the B.F. Sisk Dam, the fourth largest embankment dam
in the United States
, which allows for a total capacity of 2041000 acre.ft making San Luis Reservoir the largest off-stream
reservoir
in the United States.
Completed in 1967, the 12700 acre (5,139.5 ha) reservoir is a joint use facility, being a part of both the California State Water Project
and Central Valley Project
, which together form a network of reservoirs, dams, pumping stations, and 550 miles (885 km) of canals and major conduits to move water across California. The San Luis Reservoir is located in Merced County
, and has a visitor center located at the Romero Outlook where visitors can learn more about the dam and reservoir. The surface of the reservoir lies at an elevation of approximately 544 ft (165.8 m), with the O'Neill Forebay
below the dam at 225 ft (68.6 m) above sea level. This elevation difference allows for a hydroelectric plant to be constructed - the Gianelli Hydroelectric Plant. Power from this plant is sent to a Path 15
substation
, Los Banos
via a short power line
. Those 500 kV
wires, carrying both the power generated here and elsewhere, leave the area and cross the O'Neill Forebay on several man-made island
s.
Camping is available at four campgrounds.
Improved boat launch ramps are offered at Dinosaur Point and the Basalt area. Due to the reservoir's water being imported from the Sacramento River Delta, San Luis shares many of its fish species with that area, including largemouth bass
, striped bass
, crappie
, bluegill
, shad
, yellow perch
, and occasional sturgeon
and salmon
.
The lake is noted for its high winds and has wind warning lights at Romero Outlook, Basalt Campground, and Quien Sabe Point.
Average annual precipitation is 10.36 inches (263.1 mm). There are an average of 57 days annually with measurable precipitation. The wettest year was 1998 with 25.06 inches and the dryest year was 1989 with 4.88 inches. The most precipitation in one month was 9.03 inches in February 1998. The most precipitation in 24 hours was 3.70 inches on May 6, 1998. Snowfall rarely falls at the reservoir, but 1.2 inches of snow fell on January 9, 2001.
Off-stream
Off-stream refers to a water body or system that is not located in a streambed or does not receive significant natural flows from the surrounding watershed. For example, instead of moving water between lakes, an offstream pumped-storage hydroelectric system could use two large tanks of water...
artificial lake in the eastern slopes of the Diablo Range
Diablo Range
The Diablo Range is a mountain range in the California Coast Ranges subdivision of the Pacific Coast Ranges. It is located in the eastern San Francisco Bay area south to the Salinas Valley area of northern California, the United States.-Geography:...
of Merced County, California
Merced County, California
Merced County , is a county located in the Central Valley of the U.S. state of California, north of Fresno and southeast of San Jose. As of the 2010 census, the population was 255,793, up from 210,554 at the 2000 census. The county seat is Merced...
, approximately 12 mi (19.3 km) west of Los Banos
Los Banos, California
Los Banos is a city in Merced County, California, near the junction of State Route 152 and Interstate 5. Los Banos is located southwest of Merced, at an elevation of 118 feet . The population was 35,972 at the 2010 census, up from 25,869 at the 2000 census...
on State Route 152
California State Route 152
State Route 152 is a state highway that runs near the latitudinal middle of the U.S. state of California from Watsonville to Route 99 southeast of Merced...
, which crosses Pacheco Pass
Pacheco Pass
Pacheco Pass, elevation , is a mountain pass located in the Diablo Range in southeastern Santa Clara County, California. It is the main road over the hills separating the Santa Clara Valley and the Central Valley....
and runs along its north shore. The reservoir stores water taken from the San Joaquin-Sacramento River Delta as the surplus water would otherwise run into the Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
. Water is pumped uphill into the reservoir from the O'Neill Forebay
O'Neill Forebay
O'Neill Forebay is a forebay to the San Luis Reservoir created by the construction of O'Neill Dam across San Luis Creek approximately west of Los Banos, California, on the eastern slopes of the Pacific Coast Ranges of Merced County.-Background:...
which is fed by the California Aqueduct
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. The Department of Water Resources operates and maintains the...
and is released back into the forebay to continue downstream along the aqueduct as needed for farm irrigation and other uses. Depending on water levels, the reservoir is approximately nine miles long from north to south at its longest point, and five miles (8 km) wide. At the eastern end of the reservoir is the San Luis Dam
San Luis Dam
San Luis Dam is a dam that creates San Luis Reservoir, which serves as an off-stream reservoir for the California State Water Project and the Central Valley Project. It is also known as the B.F. Sisk Dam, after Bernie Sisk. The earth-fill gravity embankment dam is 305 feet tall and was completed...
, or the B.F. Sisk Dam, the fourth largest embankment dam
Embankment dam
An embankment dam is a massive artificial water barrier. It is typically created by the emplacement and compaction of a complex semi-plastic mound of various compositions of soil, sand, clay and/or rock. It has a semi-permanent waterproof natural covering for its surface, and a dense, waterproof...
in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, which allows for a total capacity of 2041000 acre.ft making San Luis Reservoir the largest off-stream
Off-stream
Off-stream refers to a water body or system that is not located in a streambed or does not receive significant natural flows from the surrounding watershed. For example, instead of moving water between lakes, an offstream pumped-storage hydroelectric system could use two large tanks of water...
reservoir
Reservoir
A reservoir , artificial lake or dam is used to store water.Reservoirs may be created in river valleys by the construction of a dam or may be built by excavation in the ground or by conventional construction techniques such as brickwork or cast concrete.The term reservoir may also be used to...
in the United States.
Completed in 1967, the 12700 acre (5,139.5 ha) reservoir is a joint use facility, being a part of both the California State Water Project
California State Water Project
The California State Water Project, commonly known as the SWP , is the world's largest publicly built and operated water and power development and conveyance system. The SWP was designed and is operated by the California Department of Water Resources...
and Central Valley Project
Central Valley Project
The Central Valley Project is a Bureau of Reclamation federal water project in the U.S. state of California. It was devised in 1933 in order to provide irrigation and municipal water to much of California's Central Valley—by regulating and storing water in reservoirs in the water-rich northern...
, which together form a network of reservoirs, dams, pumping stations, and 550 miles (885 km) of canals and major conduits to move water across California. The San Luis Reservoir is located in Merced County
Merced County, California
Merced County , is a county located in the Central Valley of the U.S. state of California, north of Fresno and southeast of San Jose. As of the 2010 census, the population was 255,793, up from 210,554 at the 2000 census. The county seat is Merced...
, and has a visitor center located at the Romero Outlook where visitors can learn more about the dam and reservoir. The surface of the reservoir lies at an elevation of approximately 544 ft (165.8 m), with the O'Neill Forebay
O'Neill Forebay
O'Neill Forebay is a forebay to the San Luis Reservoir created by the construction of O'Neill Dam across San Luis Creek approximately west of Los Banos, California, on the eastern slopes of the Pacific Coast Ranges of Merced County.-Background:...
below the dam at 225 ft (68.6 m) above sea level. This elevation difference allows for a hydroelectric plant to be constructed - the Gianelli Hydroelectric Plant. Power from this plant is sent to a Path 15
Path 15
Path 15 is an portion of the north-south power transmission corridor in California, U.S. It forms a part of the Pacific AC Intertie and the California-Oregon Transmission Project....
substation
Electrical substation
A substation is a part of an electrical generation, transmission, and distribution system. Substations transform voltage from high to low, or the reverse, or perform any of several other important functions...
, Los Banos
Los Banos, California
Los Banos is a city in Merced County, California, near the junction of State Route 152 and Interstate 5. Los Banos is located southwest of Merced, at an elevation of 118 feet . The population was 35,972 at the 2010 census, up from 25,869 at the 2000 census...
via a short power line
Electric power transmission
Electric-power transmission is the bulk transfer of electrical energy, from generating power plants to Electrical substations located near demand centers...
. Those 500 kV
Volt
The volt is the SI derived unit for electric potential, electric potential difference, and electromotive force. The volt is named in honor of the Italian physicist Alessandro Volta , who invented the voltaic pile, possibly the first chemical battery.- Definition :A single volt is defined as the...
wires, carrying both the power generated here and elsewhere, leave the area and cross the O'Neill Forebay on several man-made island
Island
An island or isle is any piece of sub-continental land that is surrounded by water. Very small islands such as emergent land features on atolls can be called islets, cays or keys. An island in a river or lake may be called an eyot , or holm...
s.
San Luis Reservoir State Recreation Area
San Luis Reservoir is part of the larger San Luis Reservoir State Recreation Area (California State Parks) and therefore offers many recreational opportunities for fisherman, boaters, and campers. The park is patrolled by California State Park Peace Officers by vehicle, vessel and off-highway vehicle. In addition to camping and boating, day use picnic areas are available at San Luis Creek and an off-highway vehicle (OHV) area is available east of the main area at the intersection of Gonzaga Road and Jaspar-Sears Road.Camping is available at four campgrounds.
- The Basalt Campground on the south-eastern edge of the lake with 79 developed family campsites. Water faucets are available nearby, and some sites can handle RV's to a length of 40 feet (12.2 m).
- San Luis Creek Campground on O'Neill Forebay with 53 sites with water and electric hook-ups.
- Medeiros Campground has primitive campsites along the southern shoreline of O'Neill Forebay. This campground has drinking water at three locations and chemical toilets.
- Los Banos Creek Campground has primitive campsites and limited turn-around space. It is not suitable for trailers or motor homes. Drinking water and chemical toilets are available.
Improved boat launch ramps are offered at Dinosaur Point and the Basalt area. Due to the reservoir's water being imported from the Sacramento River Delta, San Luis shares many of its fish species with that area, including largemouth bass
Largemouth bass
The largemouth bass is a species of black bass in the sunfish family native to North America . It is also known as widemouth bass, bigmouth, black bass, bucketmouth, Potter's fish, Florida bass, Florida largemouth, green bass, green trout, linesides, Oswego bass, southern largemouth...
, striped bass
Striped bass
The striped bass is the state fish of Maryland, Rhode Island, South Carolina, and the state saltwater fish of New York, Virginia, and New Hampshire...
, crappie
Crappie
Crappie is a genus of freshwater fish in the sunfish family of order Perciformes. The type species is P. annularis, the white crappie...
, bluegill
Bluegill
The Bluegill is a species of freshwater fish sometimes referred to as bream, brim, or copper nose. It is a member of the sunfish family Centrarchidae of the order Perciformes.-Range and distribution:...
, shad
Shad
The shads or river herrings comprise the genus Alosa, fish related to herring in the family Clupeidae. They are distinct from others in that family by having a deeper body and spawning in rivers. The several species frequent different areas on both sides of the Atlantic Ocean, Mediterranean Sea....
, yellow perch
Yellow perch
The yellow perch is a species of perch found in the United States and Canada, where it is often referred to by the shortform perch. Yellow perch look similar to the European perch, but are paler and more yellowish, with less red in the fins. They have six to eight dark, vertical bars on their sides...
, and occasional sturgeon
Sturgeon
Sturgeon is the common name used for some 26 species of fish in the family Acipenseridae, including the genera Acipenser, Huso, Scaphirhynchus and Pseudoscaphirhynchus. The term includes over 20 species commonly referred to as sturgeon and several closely related species that have distinct common...
and salmon
Salmon
Salmon is the common name for several species of fish in the family Salmonidae. Several other fish in the same family are called trout; the difference is often said to be that salmon migrate and trout are resident, but this distinction does not strictly hold true...
.
The lake is noted for its high winds and has wind warning lights at Romero Outlook, Basalt Campground, and Quien Sabe Point.
Climate
The National Weather Service has maintained a cooperative weather station at San Luis Dam since 1963. Based on those records, average January temperatures are a maximum of 54.3°F and a minimum of 37.9°F and average July temperatures are a maximum of 92.0F° and a minimum of 64.0°F. There are an average of 69.3 days with highs of 90F° (32C°) or higher and an average of 14.1 days with lows of 32°F (0°C) or lower. The record high temperature was 110°F on July 24, 2006, and the record low temperature was 14°F on December 22, 1990.Average annual precipitation is 10.36 inches (263.1 mm). There are an average of 57 days annually with measurable precipitation. The wettest year was 1998 with 25.06 inches and the dryest year was 1989 with 4.88 inches. The most precipitation in one month was 9.03 inches in February 1998. The most precipitation in 24 hours was 3.70 inches on May 6, 1998. Snowfall rarely falls at the reservoir, but 1.2 inches of snow fell on January 9, 2001.