The following page lists most dams in Sri Lanka . Most of these dams are governed by the Mahaweli Authority, while the Ceylon Electricity Board operates dams used for hydroelectric power generation. Hydroelectric dams, including small hydros accounts for nearly half of the installed power capacity of Sri Lanka.
Sri Lanka is pockmarked with many irrigation dams with its water resource distributed across nearly the entirety of the island for agricultural purposes via artificial canals and streams. Utilization of hydro resources for agricultural production dates back pre-Colonial era, with current crop productions now largely dependent on these water resources.
Irrigation dams with a length and height of more than 100 m (330 ft) and 10 m (33 ft) are listed, including all the state-run hydroelectric power stations. Privately owned "small-hydro" facilities (which are limited to a maximum nameplate capacity of 10 MW ), are not included in this list. Nearly all hydroelectric dams are also used for providing water resource for irrigation purposes, hence for the sake of identifying the hydroelectric dams, any dam with hydroelectric involvement is stated as such in the below table, even if the primary purpose of building the dam is to retain water for irrigation.
|Lower Malvathu Oya||Irrigation|
The Mahaweli River, is a 335 km (208 mi) long river, ranking as the longest river in Sri Lanka. It has a drainage basin of 10,448 km2 (4,034 sq mi), the largest in the country, which covers almost one-fifth of the total area of the island. The real beginning of Mahaweli Ganga starts at Polwathura(at Mahawila area), a remote village of Nuwara-Eliya District in bank Nawalapitiya of Kandy District by further joining of Hatton Oya and Kotmale Oya. The river reaches the Bay of Bengal on the southwestern side of Trincomalee Bay. The bay includes the first of a number submarine canyons, making Trincomalee one of the finest deep-sea harbors in the world.
The Kotmale River is the longest tributary of Mahaweli River. The river begins as the Agra Oya, in the Horton Plains. The Central Plains have an annual rainfall of between 125 and 200 inches a year. The river is approximately 70 km (43 mi) long and drains a basin of about 58,534 ha. The river flows through a traditional area of ancient villages and tea plantations. King Dutugemunu spent his youth here. The Kotmale Oya flows into the Mahaweli shortly at Pallegama. Tributaries of the Kotmale Oya include the Nanu Oya, the Pundalu Oya, the Puna Oya, and the Dambagastalawa Oya.
St. Clair's Falls is one of the widest waterfalls in Sri Lanka and is commonly known as the "Little Niagara of Sri Lanka". It is one of six waterfalls affected by the Upper Kotmale Hydropower Project.
Victoria Dam is an arch dam located 130 mi (209 km) upstream of the Mahaweli River's mouth and 4 mi (6 km) from Teldeniya. Its main purposes are irrigation and hydroelectric power production. It is the tallest dam in Sri Lanka, and supports a 210 MW power station, the largest hydroelectric power station in the country. Construction of the dam commenced in 1978, and was ceremonially completed by then-President Jayewardene in April 1985.
The Samanala Dam is a dam primarily used for hydroelectric power generation in Sri Lanka. Commissioned in 1992, the Samanalawewa Project is the third-largest hydroelectric scheme in the country, producing 405 GWh of energy annually. It was built with financial support from Japan and the United Kingdom. It is notable for a large leak on its right bank. Power production continues as planned despite the leakage, and the water from the leak now provides two thirds of the water issued by the reservoir for agriculture in downstream areas.
The electricity sector in Sri Lanka has a national grid which is primarily powered by hydro power and thermal heat, with sources such as photovoltaics and wind power in early stages of deployment. Although potential sites are being identified, other power sources such as geothermal, nuclear, solar thermal and wave power are not used in the power generation process for the national grid.
The Upper Kotmale Dam is located in Talawakele, within the Nuwara Eliya District, in the Central Province of Sri Lanka. The dam feeds the third largest hydroelectric power station in the country.
The Broadlands Dam is a 35 MW run-of-the-river hydroelectric complex currently under construction in Kitulgala, Sri Lanka. The project is expected to be completed in 2020, and will consist of two dams, and a power station further downstream.
The Moragahakanda Dam, officially as Kulasinghe Reservoir, is a large gravity dam, and the main component of the larger and more complex Moragahakanda — Kalu Ganga Project, across the Amban River at Elahera, in the Matale District of Sri Lanka. Construction began on 25 January 2007 and was completed in 2018. The maiden waters of the dam was released in January 2017. Morgahakanda/Kaluganga project is the last of the Great Mahaveli project
The Kalu Ganga Dam is a large gravity dam, and the second vital component of the larger and more complex Moragahakanda — Kalu Ganga Project, currently under construction across the Kalu Ganga at Pallegama, in the Matale District of Sri Lanka. Construction of the project was launched by President Mahinda Rajapaksa on 25 January 2007. The maiden waters of the dam was released in July 2018.
The Maskeliya Dam is a large gravity dam at Maskeliya, in the Central Province of Sri Lanka. Along with the Castlereigh Dam, the dams are the highest point and beginning of the Laxapana Hydropower Complex, involving a number of dams, penstocks, and hydroelectric power stations. The dam creates the Maskeliya Reservoir over the route of Maskeliya Oya, a major tributary of the Kelani River, which is the 4th longest in the country.
The Polgolla Barrage, is a barrage built across the Mahaweli River at Polgolla, in the Central Province of Sri Lanka. The barrage is used to increase the volume of water, for transfer to the hydroelectric power station located 8 km (5 mi) north, via penstock.
The Laxapana Dam is a gravity dam built across the Maskeliya Oya, 2.8 km (1.7 mi) downstream of the Laxapana Falls, in the Central Province of Sri Lanka.
The Gal Oya Dam is an embankment dam in the Uva Province of Sri Lanka. The dam creates one of the largest and most iconic reservoirs in the country, the Gal Oya Reservoir. Water from the reservoir is used primarily for irrigation in the Uva and Eastern provinces, in addition to powering a small hydroelectric power station. Construction of the dam and reservoir began in August 24, 1949, completing four years later in 1953.
The Deduru Oya Dam is an embankment dam built across the Deduru River in Kurunegala District of Sri Lanka. Built in 2014, the primary purpose of the dam is to retain approximately a billion cubic metres of water for irrigation purposes, which would otherwise flow out to sea. Site studies of the dam began in 2006 and construction started in 2008. It was ceremonially completed in 2014, with the presence of the then President Mahinda Rajapaksa.
Iranamadu Tank is an irrigation tank in northern Sri Lanka, approximately 3 mi (5 km) south east of Kilinochchi.
The Mahaweli Development program is known as the largest multipurpose national development program in the history of Sri Lanka and is also considered as the keystone of the government's development program that was initiated in 1961.
The Uma Oya Hydropower Complex (also internally called Uma Oya Multipurpose Development Project or UOMDP) is a irrigation and hydroelectric complex currently under construction in the Badulla District of Sri Lanka. Early assessments of project dates back to 1989, when the first studies was conducted by the country's Central Engineering and Consultancy Bureau. The complex involves building a dam across Dalgolla Oya, and channelling water over a 3,975 m (13,041 ft) tunnel to Mathatilla Oya, both of which are tributaries of the Uma Oya. At Mathatilla Oya, another dam is constructed to channel 145,000,000 m3 (5.1×109 cu ft) of water per annum, via a 15,290 m (50,160 ft) headrace tunnel to the Uma Oya Power Station, where water then discharged to the Alikota Aru via a 3,335 m (10,942 ft) tailrace tunnel. The Alikota Aru is a tributary of the Kirindi Oya.
The Moragolla Dam is a planned hydroelectric dam in Moragolla, Sri Lanka. The dam is to be 35 m (115 ft) high and is planned to create the 1,980,000 m3 (70,000,000 cu ft) Moragolla Reservoir with a maximum supply level at 548 m (1,798 ft) MSL. Upon completion, the Moragolla Power Station would have a gross installed capacity of 30 megawatts from two francis turbines, capable of generating approximately 85 GWh annually.