Ezka
The Ezka river is a tributary of the Aragon river that flows along 51 kilometers, mainly through the region of Navarra and to a lesser extent through Aragon. It rises at the junction of the Belagua and Uztárroz rivers in the Navarre town of Isaba and flows south through the valley to its mouth at the Yesa Reservoir, downstream from the Aragonese town of Sigüés.