Work of the 50’s, aimed mainly at irrigation, is one of the largest in northern Alentejo. The artifical lake is located in an area of plain and the viewpoint of Maranhão allows you to enjoy the view over the reservoir, pastures and the typical Alentejo areas.
Located in the tagus river basin, in Ribeira de Seda, this dam feeds, together with the Montargil Dam and the Magos Dam, the Sorraia Canal, a Portuguese agricultural irrigation system , which benefits about 1500 hectare owners.