The Izki River or Izkiz is a river located in Spain. It is a tributary of the Ega River, corresponding to the Ebro basin, that runs entirely through the province of Álava crossing the region of Montaña Alavesa. The river begins in the Izki Natural Park and it heads east passing through the towns Corres and Bujanda to flow into the Ega River near Santa Cruz de Campezo after obtaining water from the Berrón River. The Izki river forms part of the ZEC (Zona de Especial Conservación-The Zone of Special Conservation) Ega-Berrón (previously named LIC Ega-Berrón ES2110020) and in terms of fauna species of interest, the presence of the European mink (Mustela lutreola), a cataloged mammal "in danger of extinction", stands out . Also present in its waters is another mustelid who in the past years has seen an increase in its populations: The nutria (Lutra lutra), for which it has been classified as an Area of Special Interest for the Species Management Plan drawn up by Diputación Foral de Álava, the Provincial Council of Álava. The river's course The Izki River has a length of 15.74 km and it constitutes the central hydrologic axis of the National Park of Izki, its basin occupying about 60% of its surface. Practically all of its basin is located in an extensive forested area occupied by sands, forming a valley characterized by the existence of a large number of short-distance water courses. Upon arriving at an abrupt area dominated by calcarenite near Corres, the valley is encased in the Corres ravine, a beautiful gorge located between the Soila mountains (990 m) and the Muela (1056 m) that opens up to reach a wide alluvial plain at its convergence with the Berrón River. At that point its average annual flow is 610 L/s. In the summer, the dry season can be very marked, suffering strong drops in continuous dry periods, becoming dull in some sections. Regarding hydraulic uses, it is worth highlighting the hydraulic infrastructure installed in the Izki River ravine which consists of a dam (Aranbaltza dam) from which a surface channel starts that transports an average of 200-300 L/s. Another similar channel starts from the Berrón river, north of the town of Atauri. Both canals join in a surface deposit located near Bujanda, whose altitude (with an elevation difference of about 70m) is used by a small hydroelectric plant in Antoñana, built