Courtright Reservoir is a

reservoir A reservoir (; ) is an enlarged lake behind a dam, usually built to water storage, store fresh water, often doubling for hydroelectric power generation. Reservoirs are created by controlling a watercourse that drains an existing body of wa ...

Fresno County, California Fresno County (), officially the County of Fresno, is a county located in the central portion of the U.S. state of California. As of the 2020 United States census, the population was 1,008,654. The county seat is Fresno, the fifth-most popu ...

. The reservoir is at an elevation of 8,170 feet (2,490 m) in the Sierra National Forest, in the

Sierra Nevada The Sierra Nevada ( ) is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primari ...

Mountain Range, bordering the

John Muir Wilderness The John Muir Wilderness is a wilderness area that extends along the crest of the Sierra Nevada of California for , in the Inyo National Forest, Inyo and Sierra National Forests. Established in 1964 by the Wilderness Act and named for naturalist ...

and the Dinkey Lakes Wilderness. The high Sierra reservoir is formed by Courtright Dam in Helms Creek canyon and has a capacity of . The

dam A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, aqua ...

is composed of rock-fill and is 315 feet (96 m) tall, measured from the crest to the original streambed. It was completed in and is owned by

Pacific Gas and Electric The Pacific Gas and Electric Company (PG&E) is an American investor-owned utility (IOU). The company is headquartered at Kaiser Center, in Oakland, California. PG&E provides natural gas and electricity to 5.2 million households in the norther ...

. In 1984 the Helms Pumped Storage Powerhouse was added to the reservoir allowing it to pump water from Wishon to Courtright. Its primary purpose is

hydroelectricity Hydroelectricity, or hydroelectric power, is Electricity generation, electricity generated from hydropower (water power). Hydropower supplies 15% of the world's electricity, almost 4,210 TWh in 2023, which is more than all other Renewable energ ...

production. The lake is an "off-river" (or "off-channel") storage reservoir. In addition to the small amount of conventional hydroelectricity production from the flow of Helms Creek, Courtright Reservoir serves mainly as the upper reservoir for the Helms Pumped Storage Plant. Wishon Reservoir, an on-channel reservoir a couple of miles downstream on the Kings River, is the lower reservoir and main water source. During times of peak demand for

electricity Electricity is the set of physical phenomena associated with the presence and motion of matter possessing an electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by Maxwel ...

, when it is most expensive, water is drained from Courtright Reservoir, run through the 1,212 MW Helms Power Plant and empties into Wishon Reservoir. When demand and prices for electricity are low, water is pumped from Wishon Reservoir to Courtright Reservoir using the

power plant A power station, also referred to as a power plant and sometimes generating station or generating plant, is an industrial facility for the electricity generation, generation of electric power. Power stations are generally connected to an electr ...

's reversible

turbines A turbine ( or ) (from the Greek , ''tyrbē'', or Latin ''turbo'', meaning vortex) is a rotary mechanical device that extracts energy from a fluid flow and converts it into useful work. The work produced can be used for generating electrical ...

. Helms Power Plant is 1,000 feet (300 m) underground in a chamber carved out of solid

granite Granite ( ) is a coarse-grained (phanerite, phaneritic) intrusive rock, intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly coo ...

at the north end of Wishon Lake. It is similar to

Southern California Edison Southern California Edison (SCE), the largest subsidiary of Edison International, is the primary electric utility company for much of Southern California. It provides 15 million people with electricity across a service territory of approximate ...

's Eastwood Powerhouse near Shaver Lake, which is also a pumped-storage plant. Courtright Reservoir is a haven for weekend and outdoor enthusiasts seeking to camp, fish, hike, boat, swim, rock climb, and 4x4 among others. It is surrounded by unique domes of granite that are essentially in the center of the Sierra Batholith and are highly sought after by rock climbers from all around. It is also used during warmer-weather months by local astronomers, such as members of the Central Valley Astronomers, who take advantage of its 8,170 feet (2,490 m) elevation and excellent location for night sky viewing free from light and air pollution. As with many outdoor areas there are some animal transmittable diseases to be aware of.

Ticks Ticks are parasitic arachnids of the order Ixodida. They are part of the mite superorder Parasitiformes. Adult ticks are approximately 3 to 5 mm in length depending on age, sex, and species, but can become larger when engorged. Ticks a ...

in the area have been known infect people with the

bacterium Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the ...

that causes

tick-borne relapsing fever Relapsing fever is a vector-borne disease caused by infection with certain bacteria in the genus '' Borrelia'', which is transmitted through the bites of lice, soft-bodied ticks (genus ''Ornithodoros''), or hard-bodied ticks (Genus Ixodes). S ...

. The

yellow-bellied marmot The yellow-bellied marmot (''Marmota flaviventer''), also known as the rock chuck, is a large, stout-bodied ground squirrel in the marmot genus. It is one of fourteen species of marmots, and is native to mountainous and semi-arid regions of south ...

is known to carry

cryptosporidium ''Cryptosporidium'', sometimes called crypto, is an apicomplexan genus of alveolates which are parasitism, parasites that can cause a respiratory and gastrointestinal illness (cryptosporidiosis) that primarily involves watery diarrhea (inte ...

, which can be infectious to humans. Additionally due to the elevation and the thinner atmosphere there has been slightly higher but not dangerous levels of radiation recorded here.

References

External links

United States Forest Service
{{authority control Reservoirs in Fresno County, California Lakes of the Sierra Nevada (United States) Sierra National Forest Reservoirs in California Reservoirs in Northern California

See also

References

External links