Mauvoisin Dam

Geschichte

Mauvoisin Dam is a concrete variable radius arch dam across the Val de Bagnes on the Dranse de Bagnes stream, in the canton of Valais, Switzerland. Initial construction on the dam commenced in 1951 and was completed in 1957, with the reservoir filling by 1958. In 1991, the dam was raised to increase the capacity of the reservoir for winter storage. The dam's primary purpose is hydroelectric power generation.The eighth highest dam in the world, Mauvoisin stands 250m high and 520m long, with a structural volume of 2030000m3. The impounded water behind the dam forms the 4.9km Lac de Mauvoisin, which has a capacity of 211.5 million m3 (171,500 acre feet) and a full surface area of 208ha. The dam and reservoir control runoff from a catchment of 167km2. Flood waters are released by a gated spillway with a capacity of 107m3/s.Water from the dam is fed to two hydroelectric power stations with a combined capacity of 363 megawatts (MW). Mauvoisin Dam provides a hydraulic head of 482m to the Fionnay generating station, which can produce 138 MW from three Francis turbines. The water then drops another 1014m to the Riddes generating station, where it drives five Pelton turbines with a combined capacity of 225 MW. The two plants produce about 943 million kilowatt hours (KWh) each year, with Fionnay generating 278 million KWh (29.5%) and Riddes generating 665 million KWh (70.5%).