Kala Oya

The Kala Oya is the third longest river in Sri Lanka. It is approximately in length. The river has a basin size of , and more than 400,000 rural population live by the river basin.
Its catchment area receives approximately 3,169 million cubic metres of rain per year, and approximately 5 percent of the water reaches the sea. It has a catchment area of 1,792 square kilometers.