Abeykoon Mayadunnage Harsha Kumara Abeykoon,N. M. A. L. B. Nawarathna, National Water Supply and Drainage Board, Kelaniya Right Bank Water Treatment Plant Project, harsha80000@gmail.com
Abstract
The Kelani River and its tributaries are the main source of supply of potable and industrial water to Greater Colombo area. The present capacity of Ambatale water treatment plant is around 120MGD representing 65% to 70% of the drinking water supply of the area. With an expected increase of demand up to 175MGD in the year 2020, the ability to extract water from Kelani River is a key issue for Colombo Water Supply. The bed level of Kelani river is below 0 MSL up to about Hanwella and during low flow season, salt water of the sea propagates along the river when there is high tide, reaching Ambatale intake in the worst case, and inducing a limitation in the treated water production experienced almost every year. Among the several solutions proposed, the erection of a Salinity Barrier across the Kelani river in the vicinity of Ambatale intake has been found as the most effective solution and now it has come to its construction stage. But the sustainability of this solution is a vital topic. This paper illustrates an overall study carried out to identify the social and environmental impacts that could arise from this solution and possible mitigations.
Keywords: Salinity intrusion, Environment, Mitigation