Most of the district lies in the watershed of the Hemavathi River, a tributary of the Kaveri River. The general level of Hassan district slopes with the course of the Hemavati, from the peaks of the Western Ghats downwards to the southeast. The chief tributary of the Hemavathi is the Yagachi River, which flows southward from Belur taluk to join the Hemavathi near Gorur. In 1981 the Hemavathi Dam was completed near Gorur, downstream from the confluence with the Yagachi, creating a reservoir of 8000 hectares. The Hemavathi passes through Holenarsipur taluk in a southerly direction and joins with the Kaveri near Hampapura in Mysore district, close to the border of Hassan district. The Kaveri flows through the southernmost part of the District.