Mahadayi or Mandavi River takes it birth in the Western Ghats, at an altitude of 600 m above the sea level, in Belgaum District. Maderi is the sub tributary of Mahadayi River. The Mahadayi River has a catchment area of 2,032 sq km of which 412 sq km are in Karnataka. Before reaching the Arabian Sea, the river flows for 29 km in Karnataka before entering Goa, where its length is 52 km. The catchment area of Mahadayi River receives heavy rainfall during the southwest monsoons.