Originating at an altitude of 1650 m above sea level, to the north of the Hanumanathi is the river Karuppanathi. After traversing its way downhill, the river joins its tributary Vembunathi in the plains. It finally merges with Hanumanathi below the Urmelalagian dam built across the river. Mostly serving the irrigational needs of the state, the river from its source to its merger with the Hanumanathi has six dams constructed across it.
