Kotmale Oya

Kotmale Oya

Kotmale Oya (Sinhala: කොත්මලේ ඔය; Tamil: கொத்மலை ஆறு) Kothmale Oya is one of the seven major tributaries of the  Mahaweli Ganga , the longest river in Sri Lanka (Johansson, 1989). At Kadadora village, about 6.6 km upstream from the confluence of the Mahaweli Ganga and the Kotmale Oya, the latter has been impounded forming the Kotmale Reservoir  (Johansson, 1989; Silva, 1996). River basin Located in Nuwara Eliya District, the river is approximately 70 km long and drains a basin of about 571.20 sq. km, which is about 18.8 % of the total extent of the Upper Mahaweli Catchment (Amarathunga et al., 2014). The average annual rainfall of the basin ranges from 2,000 mm to above 4,500 mm, and the elevation ranges from 600 m to 2,524 m at Pidurutalagala (Amarathunga et al., 2014). The Agra Oya, Dambagastalawe Oya and Nanu Oya are the main tributaries of the Kotmale Oya (Silva, 1996). The Agra Oya and Dambagastalawe Oya descend along steep gradients and join together at the Caledonia Estate and flow w…