 The real creation of Mahaweli ganga starts at Polwathura(at Mahawila area), a remote village of Nuwara-Eliya District in bank Nawalapitiya of Kandy District by further joining of Hatton oya and Kotmale oya.The river reaches the Bay of Bengal on the southwestern side of Trincomalee Bay.The bay includes the first of a number submarine canyons, making Trincomalee one of the finest deep-sea harbors in the world.As part of Mahaweli Development programme the river and its tributaries are dammed at several locations to allow irrigation in the dry zone, with almost of land irrigated.