The Ten Ar River is fed from most of the valley by the Kumbar stream, the Manalaar River ("sand river"), the Kalyanivalasu Odai and other smaller tributaries from the higher forests and sholas to the east. At the northwest end of the valley, the Ten Ar is joined by the Varavandi Odai stream flowing from a smaller adjacent valley to the east and soon joins the Amaravati River down stream to the west. The Amaravati River then flows north to the Amaravathi Reservoir and Dam and then to the Cauvery River.