It is classified as a Site of Community Importance in the Natura 2000 Network. It is born in the Mountain of Leomil and runs 110 km to find the left bank of the Douro River in Castelo de Paiva. After several centuries. Rio Paiva was a source of sustenance for the populations of Castro Daire. through the fishing activity and the grinding of the diverse cereals cultivated in its slopes. today. the river provides recreational and leisure zones and is a strong attraction for the pratice of extreme sports. being considered as one of the best for practicing activities like rafting.