The Anços River originates here, at Olhos d’Água da Redinha, and meanders through the Sicó landscape. Fed by the Orão stream, it flows between discreet valleys until it delivers its waters to the Arunca River, near Soure.
The spring, a powerful resurgence connected to an underwater cavity of which only 63 meters of depth are known, is one of the great mysteries yet to be revealed in the Sicó-Alvaiázere massif.