Opak River

Opak River is a river that flows from the lower slopes of Mount Merapi and passes to the east the location of Yogyakarta and west of Kota Gede.

It also passes the historical locations of Plered, Karta, and Imogiri before draining into the Indian Ocean in the southern part of Bantul.

The river basin that it lies in is significant as the aquifer is in a heavily populated part of Java