The Madu River flows through a wetland ecosystem near the small town of Balapitiya along the Colombo-Galle Southern Highway. It is an estuary with its many mangrove islets and constitutes a complex coastal wetland. It has a high ecological, biological and aesthetic significance, home to approximately 303 species of plants belonging to 95 families and 248 species of vertebrate animals. The inhabitants of its islets produce peeled cinnamon and cinnamon oil. It was named Ramsar Wetland in 2003.