The Deduru Oya (Tamil: à ®®à ®¾à ®¯à ®µà ®©à ¯ à ®Âà ®±à ¯Â) is the sixth-longest river of Sri Lanka. The long river runs across four provinces and five districts.
Its catchment area receives approximately 4,313 million cubic metres of rain per year, and approximately 27 percent of the water reaches the sea. It has a catchment area of 2,620 square kilometres.