Malwathu Oya

The Malwathu Oya (මල්වතු ඔය Malwathu Oya, அருவி ஆறு Aruvi Aru) is the second longest river in Sri Lanka. The river originates in the North Central Province of Sri Lanka and enters the sea on the northwest coast, into the Gulf of Mannar, near Vankalai. It is a seasonal river that spans over 164 km through paddy and forest lands, which are used by the inhabitants to cultivate for their survival.

The river basin covers an area of 3,284 km2 (with a length of 125 km, a maximum width of 40 km at an average height of 85.5 m above sea level). The average annual rainfall in the basin area is 1,223 mm. The Ritigala mountain range, which comprises four main peaks (the highest of which is over 900 m high), in the upper reaches of the river, serves as the main catchment.

Tributaries

 * Kanadara Oya
 * Maminiya Oya
 * Kadahatu Oya
 * Kal Aru
 * Narivili Aru