River basins

Ibaizabal

Arrasate, Bergara, Elgeta

Iñurritza

Aia, Aizarnazabal, Getaria, Zarautz, Zestoa

Iparralde

Itsasoa

Deba, Donostia, Getaria, Hernani, Hondarribia, Lasarte-Oria, Lezo, Mendaro, Mutriku, Orio, Pasaia, Usurbil, Zarautz, Zumaia