Montanhas Mágicas® have an abundant and high-quality hydrographic network, integrating basins of the Douro in the North - municipalities of Arouca, Castelo de Paiva, Castro Daire and Cinfães, and the Vouga river in the south - Vale de Cambra, São Pedro do Sul and Sever do Vouga municipalities.
This means that the northern region is drained by the left bank of the Douro river, with emphasis on the Arda, Paiva, Bestança and Cabrum tributaries. The southern region is drained by the right bank of the Vouga river, especially by its affluents: Caima, Mau, Arões, Teixeira, Varoso, Sul and Mel. Also noteworthy are the Paivô,
Frades, Ardena, Tenente e Vidoeiro rivers, tributaries of the Paiva river.
Most of these rivers offer exceptional conditions for all sort of adventure sports, whereas the Paiva river is the best rafting spot in Portugal.