Barrage de Tignes

Barrage de Tignes. It is a major concrete arch dam located in the Tarentaise Valley of the French Alps, forming the vast Lac du Chevril reservoir. Completed in 1952, it was a cornerstone of post-war France's national hydroelectric development and remains one of the highest dams in Europe. Its construction necessitated the controversial submersion of the original village of Tignes, a pivotal event in the region's modern history.

History and Construction

The project was conceived in the immediate aftermath of World War II as part of a national effort led by Électricité de France to achieve energy independence. Preliminary studies were conducted by engineers from the Compagnie Nationale du Rhône, with final design and construction overseen by the renowned firm Coyne et Bellier. Construction began in 1948, employing thousands of workers, including many from Italy and North Africa, in challenging high-altitude conditions. The project faced significant opposition from the displaced residents of Tignes, culminating in protests and a high-profile visit by activist Abbé Pierre in 1952. Despite this, the dam was inaugurated that same year, and the old village was completely flooded by 1953, an event memorialized by the famous French Resistance fighter and later government minister Lucie Aubrac.

Technical Specifications

The Barrage de Tignes is a double-curvature concrete arch dam, an advanced design for its time. It rises approximately 180 meters from its foundations, with a crest length of nearly 300 meters. The structure contains over 700,000 cubic meters of concrete. The reservoir, Lac du Chevril, has a capacity of around 230 million cubic meters and a surface area of 2.7 square kilometers when full. Water is primarily fed from the Isère river and its tributaries, with the intake system feeding the underground Malgovert power plant. The dam's spillway capacity is designed to manage extreme flood events from the alpine catchment, and it incorporates a bottom outlet for sediment flushing.

Role in the Hydroelectric System

The dam is a key component of the Haute-Isère hydroelectric complex, operated by Électricité de France. It provides high-head storage for the Malgovert power station, located deep inside the mountain, which has an installed capacity of over 400 MW. The reservoir's large storage volume allows for strategic water release to meet peak electricity demand across the RTE grid, complementing the output of nuclear plants like those at Gravelines and Cattenom. It also regulates flow for downstream installations on the Isère river, including the Barrage de Sainte-Hélène, and contributes to the water supply for the Tignes and Val-d'Isère ski areas. Its operation is coordinated with other major dams in the Savoie region, such as the Barrage de Roselend.

Environmental and Social Impact

The creation of Lac du Chevril had profound and lasting consequences. The deliberate flooding of old Tignes displaced hundreds of inhabitants, a traumatic event that sparked national debate about progress versus heritage, echoed in later conflicts like those surrounding the Lac de Serre-Ponçon. Ecologically, the dam altered the Isère river's flow regime, sediment transport, and local microclimates. Modern environmental assessments focus on its effects on aquatic habitats and its role in mitigating downstream flood risks for communities like Bourg-Saint-Maurice. The dam's presence also influences glacial meltwater dynamics from nearby glaciers like the Grande Motte.

Tourism and Cultural Significance

Today, the dam and its reservoir are central to the Tignes ski resort, part of the Espace Killy domain with Val-d'Isère. The vast wall of the dam famously features a giant mural of Hercules, painted by artist Jean-Marie Pierret. Lac du Chevril is a summer hub for activities like hiking, fishing, and via ferrata, while the dam itself is a notable sight on the route of the Tour de France and a visit point for engineering enthusiasts. The story of the flooded village remains a powerful cultural narrative, explored in documentaries and literature, and is commemorated by the submerged church spire, visible during drawdown periods, serving as a poignant monument to the pre-dam Tarentaise Valley.

Category:Dams in France Category:Buildings and structures in Savoie Category:Hydroelectric power stations in Auvergne-Rhône-Alpes