Nervión

The Nervión river runs through the city of Bilbao, Spain into the Cantabrian Sea (Bay of Biscay). Its lowermost course, downstream of its confluence with the Ibaizabal River, is known as the Estuary of Bilbao.

Geography

The river is 72 kilometres (45 mi) long from its source at the Burgos and Alava provincial limits to the sea and runs in South to North direction. Soon after its source, the river forms a spectacular 300-metre (980 ft) waterfall in the Delika canyon (Alava) and then enters the Biscay province through the town of Orduña. It goes into Alava again through the towns of Amurrio and Llodio. Then the river runs again into the Biscay province until the Cantabrian sea, entering the Bilbao metropolitan area at Ugao-Miraballes. The tidal influence reaches 15 kilometres (9 mi) inland from the sea, at Bilbao's old town.

The main tributaries are:

Ibaizabal is considered by some to be an equally important river, so the whole system is often called Nervion-Ibaizabal and the final tract just "Estuary of Bilbao". The basin area is 1,900 square kilometres (730 sq mi).