The mighty Mahaweli River which runs through one of the most beautiful gardens in Sri Lanka at Peradeniya also is the source of a large percentage of the electrical energy of Sri Lanka .Mahaweli river(Ganga) is the largest of the 103 river basins found in Sri Lanka. It covers about 16% of the islands total area.The river itself has a winding course ,rising about 50km south of Kandy and flowing north then,north –east to sea near . Trincomalee covering a distance of 320 km . It is the only perennial river to cross the dry Zone . Sri Lanka’s all perennial rivers are called Ganga, while seasonal streams are called Oya. A number of rivers have now been developed both the irrigation and power. The Victoria project on Mahavali Ganga one of the largest in Asia.
Mahaweli 206 km (The longest river of Sri Lanka)
Malwattu Oya 104 km
Kala Oya 97 km
Kelani Ganga 90 km
Walawe Ganga 83 km
Manik Ganga 81 km
Kalu Ganga 81 km
Ging Ganga 70 km
Nilwala Ganga 46 km
