Balancing Irrigation and Hydropower: Case Study from Southern Sri Lanka

Abstract

"This report provides a case study from the Walawe river basin, in southern Sri Lanka, where a similar situation occurs. The Walawe river basin covers approximately 3,000 km2 and extends from the ridge of the central highlands of Sri Lanka, at an altitude of over 2,000 meters, down to the southern coast. The basin offers a clear contrast between, on the one hand, its highlands and its intermediate mountainous association of ridges and valleys and, on the other, the lowland plain itself. Precipitation varies significantly in the basin from over 3,000 mm in the northwestern tip to around 1,000 mm along the seashore. The highlands are cut by many valleys in which small streams, which are often perennials, can be found. They feed the Walawe river, which has an average discharge to the sea of 1.1 billion m3/yr."