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.