River Aramaio. It rises at the top of Kruzeta. It receives the Espistiko, Arrekozabal, Arrejola, Kestui and other streams that flow down from the mountains of Anboto, Aranguio, San Adrián and Asketa. It irrigates the valley of Aramayona, enters Guipúzcoa and joins the Deva at Mondragón. Its course is about eight kilometres long. River Okendo or Izalde (Oquendo). It is formed by the streams that flow down from the Sierra Salvada. Its most abundant source rises in Ozeka. It passes near Quejana (Avala), the hills of Respaldiza and Menagaray, flows through the narrow valley of Zuaza, irrigates the valley of Oquendo and enters Vizcaya to drain into the Cadagua, near Sodupe. During its course, the ravines and streams of Eskorreta, Ozobaltza, Garbea, Bortaun, Mastondo and others increase its flow.