The Asturian rivers run in their upper course embedded in deep valleys and gorges, which has led to the construction of reservoirs for the supply and generation of hydroelectric energy.
The rivers Nalón, Narcea and Caudal flow through the central zone of Asturias.
The Nalón River
The river Nalón is a river of 138 km, it is born in the Source the Nalona, in the port of Tarna, (Caso) and it ends between San Esteban de Pravia and San Juan de la Arena forming the Pravia estuary. Its length also considering the Pravia estuary is 153 km.
Its main tributaries are the Narcea, Caudal, Trubia, Cubia, Sama and El Aranguín rivers, on the left, and the Nora, Orlé and the Dele on the right.
The Narcea River
The Narcea River is the second most important river in Asturias, both in length and flow and is a tributary on the left of the Nalón River.
It is born in Fuentes del Narcea and flows into the Nalón River at the height of Forcinas (Pravia), being part of its upper course in the Natural Park of Fuentes del Narcea, Degaña and Ibias.
Its main tributaries are: on the right the Naviego, Onón, Genestaza and Pigüeña and on the left the Coto, Arganza, Gera, Rodical and Nonaya.
The Caudal River
The Caudal River is a river that runs through the central area of Asturias and is a tributary of the Nalón River, to which it spills its waters at the height of Soto de Ribera.
Born in Sovilla, Mieres (Asturias) to 256 meters of altitude, at the confluence of the Lena and Aller rivers.
In the eastern part of Asturias we can highlight two rivers, the Sella and the Deva.
The Sella River
The Sella River (in Asturian Seya) is a short coastal river in the north of Spain that flows into the Cantabrian Sea and runs through the provinces of León and Asturias.
Born in the Picos de Europa in the Fuente del Infierno, in the place called Jonseya, belonging to the town and municipality of Oseja de Sajambre (province of León) and flows into the Cantabrian Sea forming the Ribadesella estuary. It has a length of 66 kilometers and an average annual flow of 18,07 m³ / s. Its basin has an area of 1.284 km².
Its main tributaries are the Ponga and Piloña rivers, on the left, and the Dobra and El Güeña on the right.
The river Deva
The river Deva is a river that runs through Cantabria and the Principality of Asturias and flows into the Cantabrian Sea in the Tina Mayor estuary. It is a natural border between Cantabria and Asturias. Its source is in Fuente Dé (Cantabria), of multiple streams coming from the thaw. The Cares River is its largest tributary and this runs through the Asturian part, joining the Deva in the town of Panes. Both one and the other are famous for their salmon.
In the western area of Asturias we can highlight three rivers, the Navia, the Esva and the Eo.
The Navia River
The Navia river is one of the most important of the Cantabrian slope. It is born in Pedrafita do Cebreiro (Lugo) and flows into the Navia estuary. It has 159 km in length and the most important tributary is the Ibias. Its route is basically rectilinear.