The Ahar River is a tributary of the Berach River (itself a tributary of Banas River, which in turn is a tributary of Chambal river, itself a tributary of Yamuna River, which in turn is the most important tributary of Ganges River). The river flows through the Udaipur city and is its larger drainage body. The spill water of the famous Pichola and Fatehsagar lake of Udaipur district gets into the Ahar river. Though ironically, this historically important river is at present functioning as the drainage body of the Udaipur city filled with sewage and garbage.