Alqueva Dam

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Alqueva Dam
Alqueva dam.JPG
Downstream face of the dam
Alqueva Dam is located in Portugal
Alqueva Dam
Location of Alqueva Dam
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 (3,364,460 acre·ft)
Catchment area 250 km2 (97 sq mi)
Power station
Commission date 2004, 2013[1]
Turbines 4 x 129.6 MW reversible Francis-type
Installed capacity 518.4 MW

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 was full in 2012. The 518 MW 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 km2) in Western Europe.

History[edit]

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.[2]

On February 8, 2002, the 96 metre 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.[3]

In 2004, the first stage of the hydroelectric power station was commissioned, with a capacity of 259 megawatts. The second stage, with an additional 259 MW, was commissioned in 2013. The power station contains four 129.6 MW 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.[1]

Supporting infrastructure[edit]

Complementing the Alqueva dam, which is equipped with a pumped-storage hydroelectric plant, is the Pedrógão Dam, located 23 kilometers downstream from Alqueva beside the settlement of the same name and also equipped with a mini hydroelectric plant. The purpose of the Pedrógão dam is the creation of a lower reservoir for the Alqueva, for the recovery of flows, also serving as a source of water for the Ardila and Pedrógão water supply subsystems. The Álamos pumping station takes water from Alqueva and distributes it throughout the entire Alqueva water supply subsystem. Another two pumping stations, Pedrógão/Left Bank and Pedrógão/Right Bank, distribute water to the Ardila and Pedrógão subsystems respectively. The main infrastructure also includes the primary and secondary networks, pumping stations, intermediate dams, reservoirs and drainage and road networks.

Benefits[edit]

The goals of the Alqueva Multi-Purpose Project have been based on the principal shortfalls of the Alentejo region. The answers to these needs make up the project's main goals: The establishment of a strategic water reserve, with a capacity sufficient to meet all the needs of at least three successive years of drought;Guaranteed water supply to the population, industries and agriculture within the project intervention area;Amendment of the Cultural Agriculture Model, with the introduction of 120 000 hectares of a new irrigated crops in the Alentejo region;The production of non-polluting electrical energy using renewable sources; The preservation of the environment, monitoring and actively participating in the improvement of the same; The promotion of quality tourism by means of cooperation with public and private entities, the execution of Land Use Plans and systematic efforts to ensure the sustainability of the interventions;The creation of a new Corporate Climate, assuring the resource of “water”, meeting the goals for the implementation of the project and helping to provide solutions for investment in the region;The dynamization of the employment market, a direct consequence of the other goals, is vital to the reversal of the main regional statistical indicators.

Cultural heritage preservation[edit]

The implementation of the Alqueva Multi Purpose Project has entailed a considerable amount of work in the development of mitigation processes related to the existing cultural heritage. The several impact mitigation plans associated with the projects already executed or in execution, have resulted in the archaeological intervention of about 1.200 cultural heritage sites, as well as in the development of numerous activities associated with his study, protection and disclosure. All these work has implied a strong financial investment. The archaeological excavations developed within the several impact mitigation plans have allowed the concrete knowledge of human settlements of various chronologies (from prehistory to modern times) and types (necropolis, residential structures, etc.).

Prehistoric engravings[edit]

Thousands of pre-historic engravings were lost due to the construction of the dam.[3]

Images[edit]

References[edit]

External links[edit]

Official
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