The Mahaweli River (Sinhala: Mahaweli Ganga; literally: The Great Sandy River)[1] is a 335 km (208 mi) long river, currently ranking as the longest river in Sri Lanka. Its drainage basin is the largest in the country, and covers almost 1/5th of the total area of the island. The river reaches the Bay of Bengal at the north-east end of Trincomalee. It continues as a major submarine canyon, making Trincomalee one of the finest deep sea harbors in the world.[2] Due to the production of hydroelectricity, the river is heavily dammed at multiple locations. The river is also used for irrigation, which had resulted to almost 1,000 km2 (386 sq mi) of land irrigated.[3] One of the many sources of the river is the Kotmale Oya.
