Doiras HPP, A reservoir on the Navia River, in the municipality of Boal, Asturias, Spain.

Doiras HPP is a reservoir in Bual, Asturias, created by a dam across the Navia River. The water stretches across a large area bordered by rolling hills and serves primarily for electricity generation through hydroelectric stations.

The reservoir was built in 1934 as the second dam on the Navia River and later expanded in the 1950s. This project transformed the landscape and became a major source of regional electricity supply.

The reservoir's name comes from the parish of Doiras in Boal, where the dam stands. Its water also reaches the parishes of Illano and Pesoz, and the rivers Agüeria and Urubio flow into the Navia here. Besides power generation, the reservoir is used for sport and leisure.

The dam stands in the parish of Doiras, in the municipality of Boal, with the reservoir also reaching into Illano and Pesoz. The Doiras power station is about 300 m from the dam on the left bank of the Navia, while the Silvón station is about 50 m away. The reservoir is also used for sport and leisure.

The dam is a concrete arch-gravity structure 89 m high with a 165 m crest, holding back 231,000 m³ of concrete. Its spillway can discharge up to 2,393 m³/s, while the bottom outlet handles 62 m³/s. The Doiras and Silvón power stations stand close to the dam, the Silvón house only about 50 m from it.