It is located in the municipality Ponte da Barca, in Viana do Castelo District, Portugal.

[1] On 15 August 1991 the land behind the dam lying in Spain was compulsorily acquired by Portuguese company EDP (Electricidade de Portugal), based on an old deal between dictators General Franco of Spain and António de Oliveira Salazar of Portugal.

Residents of the five villages which were going to be drowned by the dam, Aceredo, Buscalque, O Bao, A Reloeira and Lantemil, supported by left-leaning political parties, immediately began protests against the building of the dam,[2] including a ten-day hunger strike.

Minimum operating level is 280 m.[1] With the 347.9 million m³ of water, 224.6 GWh of electricity can be produced.

[7][10][6][1][5] The power station contains 2 Francis turbine-generators of 317 MW (350 MVA) each in an underground powerhouse 340 m below the surface.