Mahaweli

The Mahaweli River is the longest river in Sri Lanka, measuring 335 kilometers (208 miles). It possesses the country's largest drainage basin, at 10,448 km2 (4,034 sq mi), covering over one-fifth of the island's total surface. Its rank as one of the longest rivers in Sri Lanka. The Mahaweli Ganga begins in Polwathura (at Mahawila region), a rural village in Nuwara-Eliya District, on the bank of the Nawalapitiya in Kandy District, where Hatton Oya and Kotmale Oya connect. On the southwestern edge of Trincomalee Bay, the river flows into the Bay of Bengal. Trincomalee is one of the world's best natural deep-sea harbours, with the first of a series of submarine canyons.

The Mahaweli River and its tributaries have been dammed at many locations as part of the Mahaweli Development Program to allow irrigation in the dry zone, with about 1,000 km2 (386 sq mi) of land irrigated. More than 40% of Sri Lanka's electrical demands are met by hydroelectricity generated by the Mahaweli system's six dams. Throughout history, the river has provided water for agriculture in the surrounding areas. The Kotmale Oya is one of the river's several origins. Numerous freshwater fish species live in the river, which also has pockets of plantations and grassland along its banks, as well as flowering plants and ferns. Pollution, human encroachment, alien species, unlawful development in the river's reservation section, and excess hydropower projects are all major dangers to the river.

The Mahaweli is thought to begin in the Sri Pada mountain range in Sri Lanka. The Mahaweli draws its water from the Thotupola mountain range and the Horton Plains in Kirigalpoththa.

Length: 10,448 km2 (4,034 sq mi)