Its named is due to be built next to a Celtic fort, thus named, in the province of Ávila. The reservoir of Castro de las Cogotas belongs to the Iron Age and its beginnings are from the first century BC.

It collects the water of the Adaja river because it has been assigned for the task of ensuring the supply of drinking water to several towns in the provinces of Ávila and Valladolid. Because the nearness of the reservoir to the city of Avila, the project was complemented by the construction of another mini-reservoir, called Fuentes Claras, joined the first one, which ensures the supply of drinking water in Ávila in case of emergencies.