Guadalest River Nature · Benimantell, La Marina Baixa, Alicante The río Guadalest rises at the Puerto de Confrides pass, between the Sierra de Aitana and the Sierra de la Serrella, at about 900 metres altitude, and gives its name to the Valle de Guadalest, where Benimantell, Confrides and El Castell de Guadalest are situated, within the La Marina Baixa district. With a course of 24.9 km and a basin of 123.4 km², it has an irregular Mediterranean regime, with floods between autumn and spring and low water in summer. Its waters are regulated by the Guadalest reservoir, built for irrigation and to supply water to the coast in response to tourist demand. Already within the municipality of Altea, the Guadalest joins the río Algar before flowing into the Mediterranean. Photo: No machine-readable author provided. Rodriguillo assumed (based on copyright claims). (Public domain) What to see and do in Benimantell