The Kotmale Dam is a large hydroelectric and irrigation dam in Kotmale, Sri Lanka. The dam generates power from three 67 MW turbines, totalling the installed capacity to 201 MW, making it the second largest hydroelectric power station in Sri Lanka. Construction on the dam began in August 1979 and was ceremonially completed in February 1985.
This is a rock filled dam which is constructed across the Kotmala Oya at Kadadora. That dam is 87m in height and it is 600m long. This was a project which was carried out as a sub project under the rapid Mahaweli Development Project. The financial aid was provided by the Sweden.
Kotmala Oya is a branch river of the Mahaweli River. This dam has being constructed about 6.5 km upper to the place where Kotmala Oya meets the Mahaweli River.
A large number of people (about 3000) lose their living places due to this project. They were moved to alternative areas in the country. In addition to that there were many temples sunk in the reservoir. Mahaweli maha seya is a new pagoda which was built in a memory of those temples.