The Ibaizabal (wide river in Basque) is a river that drains southeastern Biscay to the Estuary of Bilbao. It is 43 kilometres (27 mi) long from its source at Elorrio to the Nervión, and it passes by the towns of Durango and Amorebieta and joins the Nervión river at Basauri. Both rivers run then together for a short length until they merge with the sea at Bilbao. It is disputed which river is the one that actually reaches Bilbao. It is commonly agreed that it is the Nervión, but there are some who argue that the Ibaizabal carries more water.

Ibaizabal
Ibaizabal river in Abadiño
Location
Country	Spain
Physical characteristics
Source
• location	near Elorrio
Mouth
• location	Cantabric sea
Length	43 km (27 mi)
Basin size	1,900 km2 (730 sq mi)
Discharge
• average	11.8 m3/s (420 cu ft/s)