Uma Oya Power Station

The Uma Oya Hydropower Complex, also known as the Uma Oya Multipurpose Development Project (UOMDP), is an irrigation and hydroelectric system in Sri Lanka’s Badulla District. The project, first assessed in 1989 by the Central Engineering and Consultancy Bureau, aims to improve both power generation and agricultural irrigation in the region. It involves constructing a dam across Dalgolla Oya, a tributary of Uma Oya, and channeling water through a 3,975-meter (13,041 ft) tunnel to Mathatilla Oya, another tributary. At Mathatilla Oya, a second dam is built to divert 145 million cubic meters (5.1 billion cubic feet) of water annually via a 15,290-meter (50,160 ft) headrace tunnel to the underground Uma Oya Power Station.

The power station is equipped with two Pelton turbine generators, each with a 60 MW capacity, and is fed by a 600-meter (2,000 ft) vertical pressure shaft. The station, capable of generating up to 120 MW of power, is projected to produce 231 GWh annually. The 68,000 cubic meters (2.4 million cubic feet) of earth removed to create the underground cavern reflects the large scale of the project.

Power is delivered via a 132kV double-circuit transmission line, extending 21.5 kilometers (13.4 miles) to the Badulla Substation. This line is supported by over 70 transmission towers. The project’s agricultural component is significant as well, with 145 million cubic meters of water discharged annually through a 3,335-meter tailrace tunnel. This water irrigates 15 square kilometers (5.8 sq mi) of existing land and 45 square kilometers (17 sq mi) of newly cultivated land, benefiting 14 separate tanks.