Upper Kotmale Hydropower Project

Not to be confused with Kotmale Hydropower Project

Upper Kotmale Hydropower Project
The Upper Kotmale Hydropower Project, also known as Upper Kotmale Dam/Reservoir (Sinhala: ඉහළ කොත්මලේ ජලාශය), is a major hydropower project located in Talawakelle in Nuwara Eliya District, Sri Lanka.

The Sri Lankan government took initial steps to utilize the waters of the Kotmale Oya with a Master Plan for Mahaweli Development by the United Nations Development Programme (UNDP) and Food and Agriculture Organization (FAO) in 1968 (Kodituwakku & Moonesinghe, 2004). In 1980, the Upper Kotmale Hydropower Project entered the planning process when the Ceylon Electricity Board (CEB) and German Technical Cooperation (GTC) proposed a cascade of power plants, of 64-93 MW capacity, as part of a Master Plan for Electricity Supply (Kodituwakku & Moonesinghe, 2004). After a feasibility study funded by the Japan Bank for International Corporation (JICA) in 1985-1987, the hydropower project was formulated by a team of Japanese consultants (Kodituwakku & Moonesinghe, 2004). The initial proposal suggested that Caledonia is the ideal site for creating a reservoir (Amanda, 2018). However, it has also shown that there are sites in Talawakelle, Lindula, Yoxford and Wavahena suitable for dam construction (Amanda, 2018).

In 1992, the Ceylon Electricity Board decided to consider the proposed hydropower project seeking financial assistance from the Government of Japan (Kodituwakku & Moonesinghe, 2004). Although the project was proposed with a capacity of 248 MW, it was later reduced to 150 MW and the Talawakelle was chosen as the dam site (Amanda, 2018; Kodituwakku & Moonesinghe, 2004). In 1994 the Ceylon Electricity Board proposed to commence the hydropower project to contribute 530 GWH of energy to the national grid annually (Nandalal, 2007).

Delay of the project
At the conceptual stage of the project in the late 1980’s, the project was not much known to the public hence there was very little public involvement at the planning stage of the project (Nandalal, 2007). Although the project feasibility report was available to the public in 1992, the project forum was really open to them when the Environmental Impact Assessment (EIA) for the project was opened for public comments in 1995 (Nandalal, 2007). This caught up in the whirlwind of events delaying the project for about 10 years causing a huge waste of money (Nandalal, 2007). The project faced many protests due to the expected impact on the environment, waterfalls and tourism industry (Nandalal, 2007).

In 2005 the Cabinet of Ministers decided to proceed with the project after doing significant modifications such as curtailing the water diversions to minimize adverse impacts on the waterfalls and environment (Nandalal, 2007). Diversion of water from all the other waterfalls except St. Clair's Falls was curtailed in the modified project (Nandalal, 2007).

The completed project was declared open in 2012.

Dam and Reservoir
Located on the western slopes of the Great Western Mountain Range, the project area extends over the altitudes of 700-1,200 m, upstream of the existing Kotmale Reservoir and Kotmale Oya, one of the largest tributaries of the Mahaweli Ganga River (Kodituwakku & Moonesinghe, 2004; Nandalal, 2007). It harnesses the water of several streams such as Devon Oya, St. Andrews Stream, Pundal Oya, Puna Oya, Ramboda Oya, St. Claire’s and Holyrood by diverting water above several waterfalls (Kodituwakku & Moonesinghe, 2004; Nandalal, 2007).

The primary feature of the project is the concrete gravity dam which is 34 m in height (Kodituwakku & Moonesinghe, 2004). It diverts the waters through a 12.8 km long head race tunnel and 796 m long underground type penstock to an underground hydropower station installed with two generating units with two identical vertical Francis turbines with a unit capacity of 77,000 kW (Kodituwakku & Moonesinghe, 2004; Nambe, 2013)

Environmental impact
A significant environmental impact of the Upper Kotmale Hydropower Project is the reduction of water flow over several waterfalls including St. Clair's Falls (Ranawake, 2006). The Sri Lankan Government published a gazette extraordinary making the release of water from the reservoir, to maintain the waterfall compulsory (Ranawake, 2006). The other major harmful consequences associated with the project included geological instability and inundation (Kodituwakku & Moonesinghe, 2004).

Upper Kotmale Hydropower Project
1) Amanda, H.A.H., 2018. The Economic comparison of reservoir type and run of the river type hydropower plants: a case study for Upper Kotmale. Dissertation submitted in partial fulfilment of the requirements for the degree Master of Science. Department of Electrical Engineering; University of Moratuwa. pp.4-5.
2) Kodituwakku, D. and Moonesinghe, V., 2004. The EIA Process and the Upper Kotmale Hydropower Project. SARID Journal, 1(1).
3) Namba, T., 2013. Turbine design for upper Kotmale hydropower plant. pp.16-22.
4) Nandalal, H.K., 2007, October. Importance of public participation in project implementation: upper Kotmale hydropower project in Sri Lanka. In International Conference on Small Hydropower-Hydro Sri Lanka (Vol. 22). pp.1-7.
5) Ranawake, R.A.L., 2006. Waterfall maintenance of the upper Kotmale hydropower project (Doctoral dissertation).

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This page was last updated on 14 August 2023
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