The Kala Oya is the third longest river in Sri Lanka. The 145 km (90 mi) long river has a basin size of 2,873 km2 (1,109 sq mi),[1] and more than 400,000 rural population live by the river basin.[2]
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.[3]
^Emerton, Lucy (2005). Values and Rewards: Counting and Capturing Ecosystem Water Services for Sustainable Development. IUCN. p. 93. ISBN9789558177433.