The Kotmale Dam is a large hydro-electric and irrigation dam. Located at Kotmale, the dam is the second largest hydroelectric power station in Sri Lanka. Construction of the dam began in August 1979 and was completed in February 1985.

The Kotmale project includes a 90 metres high rocktiled dam across the Kotmale Oya, a tributary of the Mahaweli Ganga, a six kilometres long resexvoir holding 175 million cubic metres of water and an underground power station to which water is led through a seven kilometres long tunnel. The civil works have been executed by Swedish contractor Skanska and commissioning took place in August 1985.