Reservoir of El Grado Nature · El Grado, Somontano de Barbastro, Huesca The El Grado reservoir is located next to the municipality of El Grado, in the province of Huesca, in Somontano de Barbastro, downstream of the Mediano reservoir and on the Cinca River. The gravity dam that forms it was completed in 1969, and its water surface covers 1,273 hectares with a maximum capacity of 400 hm³, flooding the valley that lay downstream of Mediano. The Cinca canal rises from it, forming part of the Alto Aragón irrigation system and supplying the Cinca and the Aragón y Cataluña canals; its waters are also used to generate hydroelectric power. It is managed by the Confederación Hidrográfica del Ebro, and its main function remains irrigation, followed by electricity production. Photo: Juanje 2712 (CC BY-SA 3.0) What to see and do in El Grado