The Dalles Hydroelectric Dam is a concrete-gravity run-of-the-river dam spanning the Columbia River, two-miles (3 km) east of the city of The Dalles, Oregon, United States. It joins Wasco County, Oregon with Klickitat County, Washington, 192 miles (309 km) upriver from the mouth of the Columbia near Astoria, Oregon. The closest towns on the Washington side are Dallesport and Wishram.

The Army Corps of Engineers commenced work on the dam in 1952 and completed it five years later. Slackwater created by the dam submerged Celilo Falls, the economic and cultural hub of Native Americans in the region and the oldest continuously inhabited settlement in North America. On March 10, 1957, hundreds of observers looked on as the rising waters rapidly silenced the falls, submerged fishing platforms, and consumed the village of Celilo.

The reservoir behind the dam is named Lake Celilo and runs 24 miles (39 km) up the river channel, to the foot of John Day Dam. The dam is operated by the U.S. Army Corps of Engineers (USACE), and the power is marketed by the Bonneville Power Administration (BPA). It is part of an extensive system of dams on the Columbia and Snake Rivers.

The Dalles Dam Visitor Center is located at Seufert Park on the Oregon shore, and was built in 1981. Visitors used to be able to ride a tour train, which has been closed since autumn 2001. The closure is due to post-September 11 concerns, the deteriorating conditions of the tracks, and a small derailment of the train. The Columbia Hills State Park is nearby.

The Dalles Dam
Locale	Klickitat County, Washington / Wasco County, Oregon, USA
Coordinates	45°36′44″N 121°08′04″W / 45.61222°N 121.13444°W / 45.61222; -121.13444 (The Dalles Dam)
Dam and spillways
Type of dam	Concrete gravity, run-of-the-river
Height	260 feet (79 m)
Length	8,875 feet (2,705 m)
Type of spillway	Service, gate-controlled
Power station
Turbines	22
Installed capacity	2,038 MW
Maximum capacity	1,779.8 MW

Hoover Hydroelectric Dam, once known as Boulder Dam, is a concrete arch-gravity dam in the Black Canyon of the Colorado River, on the border between the US states of Arizona and Nevada.

Excavation for the powerhouse was carried out simultaneously with the excavation for the dam foundation and abutments. A U-shaped structure located at the downstream toe of the dam, its excavation was completed in late 1933 with the first concrete placed in November 1933. Filling of Lake Mead began February 1, 1935 even before the last of the concrete was poured that May. The powerhouse was one of the projects uncompleted at the time of the formal dedication on September 30, 1935—a crew of 500 men remained after the dedication to finish it and other structures. To make the roof of the powerhouse proof against bombs, it was constructed of layers of concrete, rock, and steel with a total thickness of about 3.5 feet (1.1 m), topped with layers of sand and tar.

In the latter half of 1936, water levels in Lake Mead were high enough to permit power generation, and the first three generators, all on the Nevada side, began operating. In March 1937, one more Nevada generator went online and the first Arizona generator by August. By September 1939, four more generators were operating and the dam's power plant became the largest hydroelectricity facility in the world. The final generator was not placed in service until 1961, bringing the maximum generating capacity to 1345 megawatts at the time. Original plans called for 16 large generators, eight on each side of the river, but two smaller generators were installed instead of one large one on the Arizona side for a total of 17. The smaller generators were used to serve smaller municipalities at a time when the output of each generator was dedicated to a single municipality, before the dam's total power output was placed on the grid and made arbitrarily distributable. The present contracts for the sale of electricity expire in 2017.

Before water from Lake Mead reaches the turbines, it enters the intake towers and enters four gradually narrowing penstocks which funnel the water down towards the powerhouse. The intakes provide a maximum hydraulic head (water pressure) of 590 ft (180 m) as the water reaches a speed of about 85 mph (140 km/h). The entire flow of the Colorado River passes through the turbines. The spillways and outlet works (jet-flow gates) are rarely used.^[2] The jet-flow gates, located in concrete structures 180 feet (55 m) above the river and at river level, may be used to divert water around the dam in emergency or flood conditions, but have never done so, and in practice are only used to drain water from the penstocks for maintenance.^[87] Following an uprating project from 1986 to 1993, the total gross power rating for the plant, including two 2.4 megawatt electric generators that power Hoover Dam's own operations is a maximum capacity of 2080 megawatts. The annual generation of Hoover Dam varies. The maximum net generation was 10.348 TWh in 1984, and the minimum since 1940 was 2.648 TWh in 1956. The average has been about 4.2 TWh/year.

Control of water was the primary concern in the building of the dam. Power generation has allowed the dam project to be self sustaining: proceeds from the sale of power repaid the 50-year construction loan, and those revenues also finance the multi-million dollar yearly maintenance budget. Power is generated in step with and only with the release of water in response to downstream water demands. Lake Mead and downstream releases from the dam provide water for both municipal and irrigation uses. Water released from the Hoover Dam eventually reaches the All-American Canal for the irrigation of over 1,000,000 acres (400,000 ha) of land. Water from the lake serves 8 million people in Arizona, Nevada and California.

Power from the dam's powerhouse was originally sold pursuant to a fifty-year contract which terminated in 1987. When the contracts ended, the Bureau of Reclamation assumed control of the powerplant from the Los Angeles Department of Water and Power and Southern California Edison Co. The contracts were renegotiated and implemented for a 30-year period, and will expire in 2017. The Bureau of Reclamation reports that the energy generated is allocated as follows:

Area	Percentage
Metropolitan Water District of Southern California	28.53%
State of Nevada	23.37%
State of Arizona	18.95%
Los Angeles, California	15.42%
Southern California Edison Company	5.54%
Boulder City, Nevada	1.77%
Glendale, California	1.59%
Pasadena, California	1.36%
Anaheim, California	1.15%
Riverside, California	0.86%
Vernon, California	0.62%
Burbank, California	0.59%
Azusa, California	0.11%
Colton, California	0.09%
Banning, California	0.04%

Hoover Hydroelectric Dam
Official name	Hoover Dam
Locale	Clark County, Nevada / Mohave County, Arizona, USA
Construction began	1931
Opening date	1936
Construction cost	$49 million
Owner(s)	United States Government
Dam and spillways
Type of dam	Concrete gravity-arch
Height	726.4 ft (221.4 m)
Length	1,244 ft (379 m)
Crest width	45 ft (14 m)
Base width	660 ft (200 m)
Volume	3,250,000 cu yd (2,480,000 m3)
Impounds	Colorado River
Type of spillway	2 x controlled drum-gate
Spillway capacity	400,000 cu ft/s (11,000 m3/s)
Reservoir
Creates	Lake Mead
Capacity	35.2 km3 (28,500,000 acre·ft)
Catchment area	167,800 sq mi (435,000 km2)
Surface area	247 sq mi (640 km2)
Max. water depth	590 ft (180 m)
Power station
Operator(s)	U.S. Bureau of Reclamation
Hydraulic head	590 ft (180 m) (Max)
Turbines	17 main, Francis-type
Installed capacity	2080 MW
Annual generation	4.2 billion KWh

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The Bath County Pumped Storage Station is a pumped storage hydroelectric power plant with a generation capacity of 2,772 megawatts (MW). The station is located in the northern corner of Bath County, Virginia, on the southeast side of the Eastern Continental Divide, which forms this section of the border between Virginia and West Virginia. The station consists of two reservoirs separated by about 1,260 feet (380 m) in elevation.

Bath County Pumped Storage Station cost $1.6 billion, and was constructed with 2,100 megawatts (MW) capacity. In 2004 upgrades started, increasing power generation to 510MW and pumping power to 480MW per turbine. Bath County Station is jointly owned by Dominion Generation (60%) and the Allegheny Power System (40%), and managed by Dominion. It went into operation in 1985 and is still the largest-capacity pumped-storage power station in the world.

How it works

Water is released from the upper reservoir during periods of high demand and is used to generate electricity. What makes this different from other hydroelectric dams is that during times of low demand, power is taken from coal, nuclear, and other power plants and is used to pump water from the lower to the upper reservoir. Although this plant uses more power than it generates, it allows these other plants to operate at close to peak efficiency for an overall cost savings. Back Creek and Little Back Creek, the water sources used to create the reservoirs, have a relatively small flow rate. However, since water is pumped between the reservoirs equally, the only water taken from these creeks now that the reservoirs are full is to replace the water lost to evaporation. During operation, the water level fluctuates by over 105 feet (30 m) in the 265-acre (110 ha) upper reservoir and 60 feet (20 m) feet in the 555-acre (220 ha) lower reservoir.

When generating power, the water flow can be as much as 13.5 million gallons per minute (850 m³/sec). When storing power, the flow can be as much as 12.7 million gallons per minute (800 m³/sec).

Environment

A fishing habitat was created downstream of the facility. In times of drought water quality can be maintained by using nearby recreational reservoirs to supply extra water to the creeks. The creeks and recreational reservoirs have water quality sufficient for fish.

Bath County Pumped Storage Station
Country	United States
Locale	Bath County, Virginia
Coordinates	38°12′32″N 79°48′00″W / 38.20889°N 79.8°W / 38.20889; -79.8 / 38.20889; -79.8
Status	Operational
Commission date	1985
Construction cost	US$1.6 billion
Owner(s)	Dominion Generation Allegheny Energy
Reservoir information
Surface area	1.1 km2 (0.4 sq mi)
Pumped-storage station information
Upper reservoir spillway discharge	850 m3/s (30,017 cu ft/s)
Power generation information
Installed capacity	2,772 MW

The John Day Dam Hydroelectric Power is a concrete gravity run-of-the-river dam spanning the Columbia River in the northwestern United States. The dam features a navigation lock plus fish ladders on both sides. The John Day Lock has the highest lift (110 feet) of any U.S. lock. The reservoir impounded by the dam is Lake Umatilla, and it runs 76.4 miles (123 kilometers) up the river channel to the foot of the McNary Dam. John Day Dam is part of the Columbia River Basin system of dams.

John Day Dam hydroelectric power plant is located 28 miles (45 km) east of the city of The Dalles, Oregon, and just below the mouth of the John Day River. The closest town on the Washington side is Goldendale, 20 miles (32 km) north. The closest town on the Oregon side is Rufus, Oregon. Its crest elevation is approximately 570 feet (170 m) above sea level. It joins Sherman County, Oregon with Klickitat County, Washington, 216 miles (348 kilometers) upriver from the mouth of the Columbia near Astoria, Oregon.

Construction of the John Day Dam Hydroelectric Power began in 1958 and was completed in 1971, making it the newest dam on the lower Columbia, at a total cost of US$511 million. John Day Dam was built and is operated by the U.S. Army Corps of Engineers. The dam's power generation capacity is 2,480,000 kW (overload capacity).

Specifications of John Day Dam

• Altitude: 266 feet (81 m) above sea level
• Height: 183 feet (56 m)
• Length: 7,365 feet (2,327 m)
• Navigation lock:
  • Single-lift
  • 86 feet (26 m) wide
  • 675 feet (206 m) long
• Powerhouse
  • Sixteen 135,000 kW units
  • Total capacity: 2,160 MW
  • Overload capacity: 2,485 MW
• Spillway
  • Gates: 20
  • Length: 1,228 feet (374 m)

John Day Dam
Locale	Sherman County, Oregon / Klickitat County, Washington United States
Coordinates	45°42′59″N 120°41′40″W / 45.71639°N 120.69444°W / 45.71639; -120.69444
Construction began	1958
Opening date	1971
Construction cost	US$511 million
Dam and spillways
Type of dam	Concrete gravity, run-of-the-river
Length	2,327 m (7,635 ft)
Height	56 m (184 ft)
Impounds	Columbia River
Type of spillway	Service, gate-controlled
Reservoir
Creates	Lake Umatilla
Power station
Operator(s)	U.S. Army Corps of Engineers
Type	Yes
Turbines	16 × 135 MW
Installed capacity	2,160 MW
Maximum capacity	2,485 MW

The Robert Moses Niagara Hydroelectric Power Station is a hydroelectric power station in Lewiston, New York near Niagara Falls, New York, United States. The plant diverts water from Niagara River above Niagara Falls and returns the water into the lower portion of the river near Lake Ontario. It utilizes 13 generators at an installed capacity of 2,515 megawatts (MW).

The Robert Moses Niagara Hydroelectric Power Station was built to replace power production upon the collapse of the hydroelectric Schoellkopf Power Station on June 7, 1956 in Niagara Falls. It is named after Robert Moses, a mid-20th Century urban planner in New York and is directly opposite of the Sir Adam Beck Hydroelectric Power Stations in Ontario, Canada.

Origins

The land that the Robert Moses Niagara Hydroelectric Power Plant sits on has a long history of use for hydroelectricity. In 1805, Augustus and Peter Porter of Buffalo, New York purchased the American Falls from New York in a public auction. Acquiring the rights to the eastern rapids above the falls as well, the Porter brothers envisioned building a diversion canal in order to produce hydro-electricity. Before constructing the canal or powerhouse, the Porter brothers both died and several companies unsuccessfully attempted the project afterward.

In 1853, the Niagara Falls Hydraulic Power & Manufacturing Company was first chartered and began construction on the canal in 1860. The 35 ft (11 m). wide and 8 ft (2.4 m). deep canal was completed in 1861 and in 1875, the powerhouse began to operate. The power plant produced very little electricity although in the early electric age.

In 1877, Jacob Schoellkopf purchased the canal along with the water and power rights for $71,000. Schoellkopf would improve the canal and use the powerhouse for commercial uses.

In 1881 the Schoelkopf Power Station No. 1 was constructed, which would operate until 1904. In 1898, Schoellkopf completed their second power plant, the Schoellkopf Power Station No. 2, directly in front of the original, in the gorge below the falls, with a higher 210 ft (64 m). drop. In 1904, they built Schoellkopf Stations No. 3A and 3B.

In 1886, the competing Niagara Falls Power Company, owned by the Cataract Construction Company, built what is known as the Adams Power Plant. In 1900, construction began on the Niagara Falls Power Company's Powerhouse No. 2, which was completed in 1904 a total of 11 generators.

In 1918, the First World War prompted consolidation of the two existing power companies to form a new Niagara Falls Power Company. In 1921, construction began on Schoellkopf Station No. 3C, adjacent to the previous ones. This was completed in 1924 and contained three 25 Hz generators with a total capacity of 210,000 hp (160,000 kW). In 1925, the entire set of Schoellkopf Power Stations had 19 generators which could produce 450,000 HP (335 MW).

Construction of Robert Moses Niagara Hydroelectric Power

On June 7, 1956 water had seeped into the back wall of the Schoellkopf power station No. 2 and despite worker efforts to stop the flow of water, 2/3 of the power station collapsed. The power station had already long out-lived its life-expectancy though. However, one worker was killed and damage was estimated at $100 million USD.

In order to replace the Schoellkopf Power Stations, the New York Power Authority (NYPA) planned a new power-plant at a cost of $800 million USD that would take three years to build and produce 2.4 million KWh. At the time, it was called the Niagara Power Project before it was named the Robert Moses Niagara Power Station, after Robert Moses, the NYPA head at the time.

In 1957, the United States Congress approved the project and construction began that year. The NYPA had to gain the right to 550 acres (2.2 km²) of Tuscarora Indian Reservation in order to build the 1,900-acre (7.7 km²), 22 billion gallon reservoir and did so in 1960 through a United States Supreme Court decision.

During construction, over 12 million cubic yards of rock was excavated and twenty workers had died. Construction was complete in 1961. In 1961, when the Niagara Falls hydroelectric project first went on line, it was the largest hydropower facility in the Western world.

Lewiston Pump-Generating Plant

The facility is not a typical dam, in that it was constructed not to control the flow of water in a natural river, but rather to contain a man-made 1,900-acre (7.7 km²), 22 billion gallon upper reservoir which stores the water for day-time use through a tunnel from a point upstream on the Niagara River. The opposite boundary of this forebay is another dam. This dam is part of the 240-MW Lewiston Pump-Generating Plant 43°08′33″N 79°01′18″W / 43.1425°N 79.02167°W / 43.1425; -79.02167 (Lewiston Pump-Generating Plant), which houses 12 of electrically powered pumps that can move water to another higher storage reservoir behind this second dam.

At night, a substantial fraction (600,000 gallons per second) of the water in the Niagara River is diverted to the lower reservoir by two 700 ft (210 m). tunnels. Electricity generated in the Moses plant is used to power the pumps to push water into the reservoir behind the Lewiston Dam. The water is pumped at night because the demand for electricity is much lower than during the day. In addition to the lower demand for electricity at night, less water can be diverted from the river during the day because of the desire to preserve the appearance of the falls. This prevents the plant from withdrawing such a large amount water during other times of low demand, such as weekends. During the following day, when electrical demand is high, water is released from the upper reservoir through generators in the Lewiston Dam. That same water flows into the main reservoir, where it falls again through the turbines of the Moses plant. Some would say that the water is "used twice." This arrangement is called pumped-storage hydroelectricity.

This system allows energy to be stored in vast quantities. At night, the potential energy in the diverted water is converted into electrical energy in the Moses plant. Some of that electrical energy is used to create potential energy when the water is pumped into the reservoir behind the Lewiston Dam. During the day, part of the potential energy of the water in the Lewiston reservoir is converted into electricity at the Lewiston Dam, and then its remaining potential energy is captured by the Moses Dam, which is also capturing the potential energy of the water diverted from the river in real-time.

Beginning in 2012 and continuing through 2020, the pump-generating plant will be undergoing a $460 million modernization that will increase the plant's efficiency and service life. Previously, a refurbishment of the Robert Moses Plant was completed in 2006.

Robert Moses Niagara Hydroelectric Power Station
Locale	Lewiston, New York, United States
Coordinates	43°08′35″N 79°02′23″W / 43.14306°N 79.03972°W / 43.14306; -79.03972Coordinates / 43.14306; -79.03972
Commission date	1961
Power station information
Generation units	13
Power generation information
Installed capacity	2,525 MW

The Chief Joseph Dam is a hydroelectric power plant, concrete gravity dam on the Columbia River, 2.4 km (1.5 mi) upriver from Bridgeport, Washington, USA. The Chief Joseph Dam was authorized as Foster Creek Dam and Powerhouse for power generation and irrigation by the River and Harbor Act of 1946. The River and Harbor Act of 1948 renamed the project Chief Joseph Dam in honor of the Nez Perce chief who spent his last years in exile on the Colville Indian Reservation. Like the nearby Grand Coulee Dam, Chief Joseph Dam completely blocks salmon migration on the upper Columbia River.

The Construction of Chief Joseph Dam Hydro electric power plant began in 1949, with the main dam and intake structure completed in 1955. Installation of the initial generating units was completed in 1958. Eleven additional turbines were installed between 1973 and 1979, and the dam and lake were raised 3 m (10 ft), boosting the capacity to 2,620 MW, making Chief Joseph Dam the second largest hydroelectric power producer in the United States.

The Chief Joseph Dam is 877 km (545 mi) upriver from the mouth of the Columbia at Astoria, Oregon. It is operated by the USACE Chief Joseph Dam Project Office, and the electricity is marketed by the Bonneville Power Administration.

Chief Joseph Dam is a run-of-the-river dam which means the lake behind the dam is not able to store large amounts of water. Water flowing to Chief Joseph Dam from Grand Coulee Dam must be passed on to Wells Dam at approximately the same rate. With 27 main generators in the powerhouse, it has the hydraulic capacity of 6,030 m³/s (213,000 cu ft/s).

In the event more water flows to Chief Joseph Dam than could be used for power generation, the spillway gates would be opened to pass the excess water. With an average annual flow rate of 3,058 m³/s (107,992 cu ft/s), the Columbia River seldom exceeds the powerplant’s capability to pass water, and spilling of water is infrequent at Chief Joseph Dam.

The reservoir behind the dam is named Rufus Woods Lake, and runs 82 km (51 mi) up the river channel. Bridgeport State Park, on the lake, is adjacent to the dam.

Chief Joseph Dam
Locale	Douglas and Okanogan counties, United States
Coordinates	47°59′43″N 119°38′00″W / 47.99528°N 119.6333333°W / 47.99528; -119.6333333Coordinates: 47°59′43″N 119°38′00″W / 47.99528°N 119.6333333°W / 47.99528; -119.6333333
Construction began	1949
Opening date	1979
Dam
Type of dam	Concrete-gravity, run-of-the-river
Length	5,962 ft (1,817 m)
Height	236 ft (72 m)
Base width	164 ft (50 m) Crest:22 ft (7 m)
Impounds	Columbia River
Type of spillway	Service, gate-controlled
Discharge capacity of spillway	6,030 m3/s (212,947 cu ft/s)
Reservoir
Creates	Rufus Woods Lake
Capacity	516,000 acre foot (636,000,000 m3)
Catchment area	75,400 sq mi (195,285 km2)
Surface area	13.1 sq mi (34 km2)
Power station
Operator(s)	USACE
Type	Yes
Turbines	27 x Francis turbines
Installed capacity	2,620 MW