Reservoir of Irueña
It is the responsible for controlling the Agueda river, in which the small reservoir of Agatha is also, and is one of the most beautiful rivers in the basin of the Duero. It rises in the Sierra de Gata, near Portugal, and has a length of 133 kilometers.
Irueña¿s dam takes its name from an old, very Romanized, Celtic fort and which apparently was inhabited until the late Middle Ages. This fort, located at the confluence of the Agueda river with the stream of Rolloso, is placed 30 meters above the waters of the reservoir.