Lac de Tignes

Lac de Tignes is a major reservoir located in the Tarentaise Valley of the French Alps. Created by the damming of the upper Isère river, it lies at an altitude of approximately 1,800 meters near the commune of Tignes. The lake is a central feature of the Tignes and Val-d'Isère ski area, forming part of the Espace Killy, and plays a crucial role in hydroelectricity generation, water supply, and alpine tourism.

Geography and Hydrology

The lake is situated in the Vanoise Massif, within the Graian Alps, and is fed primarily by the Isère river along with meltwater from several glaciers, including the Grande Motte glacier. It occupies a natural glacial basin that was significantly enlarged by the construction of the Chevril Dam. The reservoir's watershed encompasses high-altitude terrain within the Vanoise National Park, contributing to its inflow from seasonal snowmelt and precipitation. The outflow continues as the Isère, which eventually joins the Rhône near Valence.

History and Construction

The creation of the modern reservoir was driven by post-war energy demands and the development of the Tignes ski resort. The original village of Tignes was submerged following the completion of the Chevril Dam in 1952, a project undertaken by Électricité de France. The construction and flooding were controversial, leading to significant local opposition and the forced relocation of residents. The dam itself, an arch-gravity structure, was a major engineering feat of its time and facilitated the subsequent expansion of winter sports infrastructure in the Tarentaise Valley.

Tourism and Recreation

Lac de Tignes is a hub for year-round alpine activities. In winter, its frozen surface is integrated into the Espace Killy ski domain, hosting cross-country skiing tracks and serving as a landing area for helicopter skiing operations. The surrounding slopes are laced with lifts operated by Compagnie des Alpes and feature events like the X Games and stages of the Alpine Ski World Cup. During summer, the lake is used for sailing, windsurfing, paddleboarding, and fishing, while the surrounding trails attract hikers and mountain bikers. The Tignes resort also hosts the annual Tignes Ice Diving competition.

Environmental Aspects

The reservoir's operations interact with the sensitive ecosystems of the Vanoise National Park. Management practices aim to balance water level fluctuations for power generation with the preservation of riparian habitats. Studies monitor impacts on local flora and fauna, including species like the Alpine ibex and Alpine marmot. The presence of the lake also influences local microclimates and sediment transport in the upper Isère basin. Environmental regulations enforced by the French Office for Biodiversity govern activities to protect water quality and alpine biodiversity.

Infrastructure and Management

The Chevril Dam and associated hydroelectric plant are key assets of Électricité de France's network in the Rhône-Alpes region. Water management is coordinated with other reservoirs in the Tarentaise Valley, such as Lac du Chevril, to optimize electricity production and ensure downstream water supply. The infrastructure supporting tourism includes the Tignes funicular, numerous gondola and chairlift systems, and extensive snowmaking facilities. The lake's shores are developed with promenades, marinas, and the Tignes leisure center, all managed by the local commune and the Savoie departmental council.