Reservoir of Porma, Reservoir in the province of León, Spain

The Reservoir of Porma is a reservoir on the Porma River in the municipality of Boñar, León Province, impounded by a concrete gravity dam 77.6 m high above its foundations and 251.4 m long along the crest. The dam, renamed Presa de Juan Benet in 1994, holds back up to 317 hm³ of water spread over roughly 11.5 km² at the normal level of 1096 m. Water also arrives from the Curueño through a tunnel about 6 km long beneath the mountain.

Construction of the dam began in 1961 and was completed in 1968, creating a reservoir of 317 hm³ that submerged the villages of Vegamián, Campillo, Ferreras, Quintanilla, Armada and Lodares. The concrete gravity dam, 77.6 m high with a 251.4 m crest, was designed by engineers including the Madrid-born writer Juan Benet; in 1994 the wall was renamed Presa de Juan Benet.

Locals also call it Embalse de Vegamián, after the village submerged beneath its waters. The dam wall was renamed Presa de Juan Benet in 1994, the year the Madrid-born engineer and writer who worked on its design died; the reservoir itself keeps the official name Embalse del Porma. In 2017 the Fundación Cerezales Antonino y Cinia held an exhibition on the dam's impact on the comarca.

The dam lies in the municipality of Boñar, and the reservoir is reached by road from Boñar and from León. The villages of Rucayo and Valdehuesa were long cut off by a narrow dirt track, asphalted in the 1980s and widened at the start of the 21st century. The dam crown stands at 1,098 m above sea level, so weather can change quickly.

The dam wall was renamed Presa de Juan Benet in 1994, after the death of the Madrid engineer and writer who had worked on its design; the reservoir itself keeps the official name Embalse del Porma. Locals still call it embalse de Vegamián, after the village submerged beneath the water.