Pantà de Sallente, Reservoir in Spain

The Pantà de Sallente lies at 1,765 m in the Vall Fosca, Pallars Jussà, and is fed by the Estany Gento, which gathers about 26 glacial lakes through underground pipes. The reservoir is 1 km long, covers 29 ha, reaches 80 m deep and has a 2 km perimeter. Its only role is to store the water the reversible Sallente power station uses by day and pumps back up to Gento by night.

The reservoir was built in 1985 to store water for a hydroelectric power station, though the system is based on tunnels and channels created in the early 1900s for earlier construction projects. This engineering infrastructure connects water from multiple glacial lakes through underground passages to generate electricity.

The name Sallente comes from the Flamisell valley, and the reservoir's water is used by the reversible Gento-Sallente plant, which pumps it back up to Estany Gento at night. Since 1992 the funicular built in 1981-1982 to carry construction material between Sallente and Gento has run for summer tourists, climbing 354 m over 692 m.

You can drive from La Torre de Cabdella on a paved road to reach the reservoir area, or walk a marked trail following an old railway line built in 1912 that takes a few hours. Bring your own water since there are no shops or fountains along the way, and wear comfortable shoes and sun protection.

The four penstocks linking Estany Gento to the Sallente plant drop 600 m at a gradient of 104.6%, and the same turbine that generates power also pumps water back up. Pumping costs about 30% more kilowatts than the descent yields, but because it happens at night, when power is four to five times cheaper, the operation pays off.