Irrigation reservoir performance : a case study of Lunugamvehera reservoir

Abstract

Lunugamwehera reservoir is a large water body with a storage capacity of 170,000 Act, constructed under the Kirindi Oya Irrigation and Settlement Project (Figure 1). The Kirindi Oya development project was commissioned in March 1986. Lunugamwehera reservoir under this project is located in the relatively dry zone in South-East quadrant of Sri Lanka at a distance of approximately 260km from Colombo. Lunugamwehera at full capacity spreads over an area of 7450 acres. Lunugamwehera reservoir which is constructed across Kirindi Oya has a drainage area of 353 square miles. Drainage basin of Kirindi Oya is narrow and extends from Bandarawela at 6350 ft MSL for a distance of 75 miles to the sea at Kirinda. Total watershed area of Kirindi Oya is 455 sq. miles (Dharmasena 1986). The Lunugamwehera reservoir consists of a left bank and right bank canal system. It provides water to about 25 small villages with 5000 families located at close proximity. There is a drinking water supply scheme to serve people in the region and water supply is extended to an animal and diary development project to develop livestock resource. Other than the above, approximately 10,500 acres in Tissa region receives water through a network of 5 old tank network downstream of the Lunugamwehera reservoir.