Flood prevention 2003 (≈ 2003)
Dams avoid major flooding.
2009
Celebration of 50 years
Celebration of 50 years 2009 (≈ 2009)
Discovery day and fireworks.
2013
Tourism Convention
Tourism Convention 2013 (≈ 2013)
EDF is committed to maintaining the water level.
Aujourd'hui
Aujourd'hui
Aujourd'hui Aujourd'hui (≈ 2025)
Position de référence.
Key figures
Henri Marty - Architect
Co-conceptor of the Grandval Dam.
Louis Marty - Architect
Co-conceptor of the Grandval Dam.
Origin and history
The Grandval Dam is a French hydroelectric project in the Central Massif, built in 1960 by architects Henri and Louis Marty. It is located on the Truyère, in the Cantal department, between the communes of Fridefont and Lavastrie, in the Auvergne-Rhône-Alpes region. This 88-metre-high multi-chamber, concrete buttress dam has been operated by Électricité de France (EDF) since 1958. It allows annual production of 125 GWh thanks to two production groups of 34 MW each.
Construction of the dam began in 1955, with water entry from the dam in 1959 and commissioning in 1960. The lake, with an area of 1,100 hectares and a volume of 271 million cubic metres, extends 28 kilometres and waters several municipalities of the Cantal and Lozère. It is dominated by the castles of Alleuze and Longevialle, and crossed by the viaduct of Garabit.
In 2003, the dam played a key role in preventing Truyère floods, avoiding floods similar to those of 1977. In 2013, EDF signed a convention to maintain the lake water level to support local tourism. The dam was also used as a backdrop for films such as L'Enfer d'Henri-Georges Clouzot and La Grande Vadrouille, shot in 1966.
The site celebrated its fifty years in 2009 with discovery days and fireworks. The Grandval plant, equipped with Francis turbines, remains a major component of the Central Massif hydropower production. The dam is also a tourist attraction, with its lake and surrounding landscapes.
The tributaries of the Truyère, such as the Bes and Ander, feed the restraint, while works such as the Garabit viaduct add to the attractiveness of the site. The dam illustrates the alliance between modern engineering and natural heritage, while contributing to the management of the region's water and energy resources.
