Lac de Cap-de-Long is a man‑made reservoir situated in the French Pyrenees, in the department of Haute‑Garonne, Occitanie region. The lake is formed by the Cap‑de‑Long dam on the Lez River, a tributary of the Garonne, and lies near the commune of Bagnères‑de‑Luchon.
Location
- Geographic coordinates: approximately 42°44′N 0°31′E.
- Altitude: about 1,850 m (6 070 ft) above sea level.
- Administrative area: Haute‑Garonne, Occitanie, France.
- The reservoir is located within the Pyrenees mountain range, close to the border with Spain.
Physical characteristics
- Surface area: roughly 0.44 km² (44 ha).
- Maximum depth: approximately 61 m, corresponding to the height of the dam.
- Total water volume: estimated at 15 hm³ (15 million m³).
- Catchment area: the Lez River watershed, encompassing alpine terrain.
History and construction
- The Cap‑de‑Long dam was constructed between 1909 and 1912 to harness hydro‑electric power for the surrounding region.
- The dam is a concrete arch structure, designed to withstand the high alpine hydrological conditions.
- The reservoir was initially intended to support industrial electricity generation and later expanded its role to include water supply and flood regulation.
Uses
- Hydroelectric generation: The water stored in Lac de Cap‑de‑Long is utilized by Électricité de France (EDF) for electricity production through the associated power plant.
- Recreation: The lake is a popular destination for fishing (notably brown trout), sailing, kayaking, and hiking. Several marked trails lead to and around the reservoir, providing access for tourists and outdoor enthusiasts.
- Water management: The reservoir contributes to regional water regulation, including downstream flow control for the Lez and Garonne rivers.
Ecology
- The alpine environment surrounding Lac de Cap‑de‑Long supports a range of flora and fauna typical of high‑altitude Pyrenean ecosystems, such as dwarf shrub communities, alpine grasses, and bird species including the golden eagle (Aquila chrysaetos).
- The lake’s cold, oxygen‑rich waters provide a habitat for trout and other cold‑water fish species.
Access and infrastructure
- The lake is reachable via the D618 road, which connects Bagnères‑de‑Luchon to the high‑mountain passes of the Pyrenees.
- Parking areas and modest visitor facilities are available near the dam, enabling day‑trippers and hikers to access the site.
- Seasonal weather conditions can restrict access during winter months due to heavy snowfall and ice.
References
- French hydro‑electric operator (EDF) technical publications on the Cap‑de‑Long dam and reservoir.
- Topographic maps of the Haute‑Garonne department (IGN).
- Regional tourism guides for the Pyrenees (Occitanie tourism board).
Note: All data presented are derived from publicly available technical and geographic sources; where specific measurements are approximated, they reflect the most recent reliable publications.
