The Cadagua or Kadagua River drains the Biscayan area of Encartaciones (Basque: Enkarterriak), from the Castilian valley of Mena to Barakaldo and Bilbao, where it forms the border between these municipalities and ends at the Estuary of Bilbao. Another important town that this river crosses is Balmaseda.
Four small hydropower plans produce electricity thanks to the river Cadagua. Until the last decades of the 20th century, this water power was also used by several mills that can be nowadays seen by the river basin.
