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Alqueva Dam

Alqueva Dam
Alqueva dam.JPG
Downstream face of the dam
Alqueva Dam is located in Portugal
Alqueva Dam
Location of Alqueva Dam in Portugal
Official name Barragem do Alqueva
Country Portugal
Location Alqueva/Moura
Coordinates 38°11′51″N 7°29′47″W / 38.19750°N 7.49639°W / 38.19750; -7.49639Coordinates: 38°11′51″N 7°29′47″W / 38.19750°N 7.49639°W / 38.19750; -7.49639
Purpose Water supply, irrigation, power, tourism
Status Operational
Construction began 1995
Opening date 2002
Construction cost US$1.7 billion
Dam and spillways
Type of dam Arch
Impounds Guadiana
Height 96 m (315 ft)
Length 458 m (1,503 ft)
Width (crest) 7 m (23 ft)
Dam volume 687,000 m3 (898,562 cu yd)
Reservoir
Inactive capacity 4,150,000,000 m3 (3,360,000 acre·ft)
Catchment area 250 km2 (97 sq mi)
Power station
Commission date 2004, 2013
Type Conventional/Pumped-storage
Turbines 4 x 129.6 MW (173,800 hp) reversible Francis-type
Installed capacity 518.4 MW (695,200 hp)

The Alqueva Dam is an arch dam and the center-piece of the Alqueva Mutlipurpose Project. It impounds the River Guadiana, on the border of Beja and Évora Districts in south of Portugal. The dam takes its name from the town of Alqueva to its right bank. It creates a large reservoir with an inter-annual regulation capacity from which water may be distributed throughout the region. The dam was completed in 2002 and its reservoir reached the full level, for the first time, in 2010. The 518.4-megawatt (695,200 hp) power station was commissioned in two stages, stage I in 2004 and stage II in 2013. The Alqueva Dam constitutes one of the largest dams and artificial lakes (250 square kilometres (97 sq mi)) in Western Europe.

During the 1950s, the Portuguese Prime Minister, António de Oliveira Salazar, ordered a study of the feasibility of the dam project. The potential benefits of the Alqueva dam were discussed for decades. An initial effort was undertaken after the Carnation Revolution of 1974, but it was abandoned in 1978. The Portuguese government eventually made a firm decision to build the dam in the 1990s, during the Cavaco Silva and António Guterres governments.

Aldeia da Luz, a small village that lay in the projected flood zone of the dam, was completely rebuilt on a new site.

The construction of the new dam was carried out by a joint venture of Bento Pedroso Construções, Cubiertas y MZOV, Dragados and Somague - Sociedade de Construções.

On February 8, 2002, the 96-metre (315 ft) high floodgates of the Alqueva dam were closed. In January 2010 the lake was filled to the planned level, with a surface area of 250 km2.

In 2004, the first stage of the hydroelectric power station was commissioned, with a capacity of 259-megawatt (347,000 hp) megawatts. The second stage, with an additional 259 MW, was commissioned in 2013. The power station contains four 129.6-megawatt (173,800 hp) reversible Francis turbines. With these turbines, the power station is afforded a pumped-storage capability. Power is generated during high demand periods and at times of low demand, the turbines reverse and pump water from a much smaller reservoir below the dam back into the main reservoir. Pedrogao Dam forms the lower reservoir.


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