Upper Kotmale Dam
Encyclopedia
The Upper Kotmale Dam is a large hydroelectric dam currently under construction in Talawakele, within the Nuwara Eliya District
, in the Central Province of Sri Lanka
. Once completed in late 2011, the facility will be the third largest hydroelectric dam in the country.
funded a study between 1985 and 1987 to further examine the hydroelectric potential in the upper reaches of Kotmale River. The feasibility study included five sites and eight alternative development schemes, and concluded with two sites which were more technically and economically feasible.
The two sites were a conventional type at Caledonia, and a run-of-the-river
type at Talawakele
. The project at Caledonia involved the displacement of over 2,700 families and inundation of large areas of land used for tea plantations
, and thus the Caledonia site was dropped. Further funding was then provided by Japan for the engineering study, which included a review of the feasibility study, selection of an optimal development plan, development of the detailed design, and the preparation of tender documents and an environmental impact assessment report.
The environmental impact assessment report was completed in September 1994, with the final design report completed in March 1995. The environmental assessment identified key issues associated with the project, which includes impact on St. Clair's Falls aesthetics due to stream flow reductions, social impacts due to resettlement of affected people, possible effects on ground water due to tunnelling, impacts on downstream water uses due to de-watering of streams, and impacts on biodiversity. These impacts led large delays in project development.
As per the National Environmental Act of 1998, the environmental clearance was then granted to the project. The project initially faced several objections, before being officially permitted by courts of law. Construction work on the project then began in 2006, and is expected to be completed by the end of 2011.
.44 billion, of which Rs.5.931 billion was funded by the Ceylon Electricity Board
, and ¥
33.265 billion by the Japan Bank for International Cooperation
. The entire project covers an area of approximately 540 square kilometre, and is developed in five phases:
A total of 2,250 construction workers are employed at the site, of which 2,100 are locals, and 150 are foreign.
respectively, while the tailwater
level is 703 m (2,306 ft) AMSL. Water from the reservoir will be used for both irrigation
development and hydroelectric power generation
.
, before stretching a further 5.5 km (3.4 mi) north-west towards Kumbaloluwa and ending up at its powerhouse at the Kotmale River near Niyamgamdora
, at approximately 07°02′33"N 80°39′23"E, 2 km (1.2 mi) downstream of the confluence of Pundal River and the Kotmale River. Excavation on the tunnel was completed and ceremonially opened by President
Mahinda Rajapaksa
on the 4th of November, 2010.
. It has installed electrical capacity of from two turbines
, capable of producing up to of power annually. Water arrives at the powerhouse from the dam via the 12.89 km (8 mi) long Upper Kotmale Tunnel, which then feeds the 793 m (2,602 ft) penstock
. The initial 745 m (2,444 ft) of the penstock is single-lane, while the latter 48 m (157 ft) splits into two lanes, feeding the two generators respectively.
The powerhouse consists of the two three-phase vertical-axis Francis turbine
-generators, two three-phase transformer
s, and a 220kV
Gas Insulator Switchgear
(GIS) substation. An outdoor switchyard measuring 36.5 m (119.8 ft) by 130 m (426.5 ft) would then connect the powerhouse to the national grid via an 18 km (11 mi) long double-circuit transmission line
which connects the switchyard to the national grid at the existing Kotmale Substation at 07°07′18"N 80°34′51"E. Two megawatts from each of the generators will be utilized to run the Upper Kotmale facility itself, thus the net production will be instead of .
The line consists of 45 towers and has a length of 15.5km. The double circuit transmission line has a capacity of 220MW
per circuit.
Similar most other dam's impacts on rivers around the world, the Upper Kotmale Dam will periodically stop the St. Clair's Falls, located 2.2 km (1.4 mi) downstream of the dam, and a further 2.9 km (1.8 mi) of the Kotmale River downstream of St. Clairs Falls, before the river is restored by water from the Devon River, the river forming the picturesque Devon Falls
. As ordered by the Government Extraordinary, the St. Clair's waterfall will maintain a continuous flow of 47250 cubic metre of water for 10 hours and 30 minutes daily, between sunrise and sunset.
Nuwara Eliya District
Nuwara Eliya District is a district in Central Province, Sri Lanka. Its area is 1,228 km². Nuwara Eliya town is a tourist attraction.-Demographics:...
, in the Central Province of Sri Lanka
Sri Lanka
Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka is a country off the southern coast of the Indian subcontinent. Known until 1972 as Ceylon , Sri Lanka is an island surrounded by the Indian Ocean, the Gulf of Mannar and the Palk Strait, and lies in the vicinity of India and the...
. Once completed in late 2011, the facility will be the third largest hydroelectric dam in the country.
History
The project was initially planned in 1968 by the local authorities, before the Government of JapanGovernment of Japan
The government of Japan is a constitutional monarchy where the power of the Emperor is very limited. As a ceremonial figurehead, he is defined by the 1947 constitution as "the symbol of the state and of the unity of the people". Power is held chiefly by the Prime Minister of Japan and other elected...
funded a study between 1985 and 1987 to further examine the hydroelectric potential in the upper reaches of Kotmale River. The feasibility study included five sites and eight alternative development schemes, and concluded with two sites which were more technically and economically feasible.
The two sites were a conventional type at Caledonia, and a run-of-the-river
Run-of-the-river hydroelectricity
Run-of-the-river hydroelectricity is a type of hydroelectric generation whereby a considerably smaller water storage called pondage or none is used to supply a power station. Run-of-the-river power plants are classified as with or without pondage...
type at Talawakele
Talawakele
Talawakele is a town in Nuwara Eliya District in Sri Lanka. It is the center of Dimbula tea planting district, the largest tea growing area in Sri Lanka. It is situated on A7 Avissawella-Nuwara Eliya highway. The altitude of Talawakele is 3,932 feet. Talawakele railway station is one of the major...
. The project at Caledonia involved the displacement of over 2,700 families and inundation of large areas of land used for tea plantations
Tea production in Sri Lanka
Tea production in Sri Lanka, formerly Ceylon, is of high importance to the Sri Lankan economy and the world market. The country is the world's fourth largest producer of tea and the industry is one of the country's main sources of foreign exchange and a significant source of income for laborers,...
, and thus the Caledonia site was dropped. Further funding was then provided by Japan for the engineering study, which included a review of the feasibility study, selection of an optimal development plan, development of the detailed design, and the preparation of tender documents and an environmental impact assessment report.
The environmental impact assessment report was completed in September 1994, with the final design report completed in March 1995. The environmental assessment identified key issues associated with the project, which includes impact on St. Clair's Falls aesthetics due to stream flow reductions, social impacts due to resettlement of affected people, possible effects on ground water due to tunnelling, impacts on downstream water uses due to de-watering of streams, and impacts on biodiversity. These impacts led large delays in project development.
As per the National Environmental Act of 1998, the environmental clearance was then granted to the project. The project initially faced several objections, before being officially permitted by courts of law. Construction work on the project then began in 2006, and is expected to be completed by the end of 2011.
Construction and development
This project is estimated to cost a total of up to RsSri Lankan rupee
The rupee is the currency of Sri Lanka, divided into 100 cents. It is issued by the Central Bank of Sri Lanka and is generally written Rs. The rupee (Sinhala: රුපියල , Tamil: ரூபாய்) (sign: ₨; code: LKR) is the currency of Sri Lanka, divided into 100 cents. It is issued by the Central Bank of Sri...
.44 billion, of which Rs.5.931 billion was funded by the Ceylon Electricity Board
Ceylon Electricity Board
The Ceylon Electricity Board , is the largest electricity company in Sri Lanka. With a market share of nearly 100%, it controls all major functions of electricity generation, transmission, distribution and retailing in Sri Lanka. It is one of the only two on-grid electricity companies in the...
, and ¥
Japanese yen
The is the official currency of Japan. It is the third most traded currency in the foreign exchange market after the United States dollar and the euro. It is also widely used as a reserve currency after the U.S. dollar, the euro and the pound sterling...
33.265 billion by the Japan Bank for International Cooperation
Japan Bank for International Cooperation
The , also known by its acronym, JBIC, is a Japanese public financial institution and export credit agency, and was created on October 1, 1999, through the merging of the Japan Export-Import Bank and the Overseas Economic Cooperation Fund ....
. The entire project covers an area of approximately 540 square kilometre, and is developed in five phases:
- Phase 1: Site preparations, construction of employers and workers living quarters, construction of access roads, and relocation of affected people.
- Phase 2: All key civil engineering works, such as construction of tunnel, dam, underground power house etc. This takes about 50% of the project cost.
- Phase 3: Hydro-mechanical works such as construction of spillways, penstocks, intake gates, etc.
- Phase 4: Electro-mechanical works such as generation installations, construction of the switchyard, fire fighting system, communication system, etc.
- Phase 5: Construction of the 15.5 km (10 mi) double-circuit power transmission lineOverhead power lineAn overhead power line is an electric power transmission line suspended by towers or utility poles. Since most of the insulation is provided by air, overhead power lines are generally the lowest-cost method of transmission for large quantities of electric energy...
.
A total of 2,250 construction workers are employed at the site, of which 2,100 are locals, and 150 are foreign.
Dam and reservoir
The gravity dam measures 35.5 m (116.5 ft) tall, and 180 m (591 ft) wide, impounding the Kotmale River and creating the Upper Kotmale Reservoir. Once filled, the reservoir will have a surface area of 250000 square metre with an average storage capacity of 800000 cubic metre. The minimum and maximum operating water levels are 1190 m (3,904 ft) and 1194 m (3,917 ft) AMSLAbove mean sea level
The term above mean sea level refers to the elevation or altitude of any object, relative to the average sea level datum. AMSL is used extensively in radio by engineers to determine the coverage area a station will be able to reach...
respectively, while the tailwater
Tailwater
Tailwater refers to waters located immediately downstream from a hydraulic structure, such as a dam , bridge or culvert. Tailwater can refer to a type of fishery...
level is 703 m (2,306 ft) AMSL. Water from the reservoir will be used for both irrigation
Irrigation
Irrigation may be defined as the science of artificial application of water to the land or soil. It is used to assist in the growing of agricultural crops, maintenance of landscapes, and revegetation of disturbed soils in dry areas and during periods of inadequate rainfall...
development and hydroelectric power generation
Hydroelectricity
Hydroelectricity is the term referring to electricity generated by hydropower; the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy...
.
Tunnel
The 4.5–5.2 m (14.8–17.1 ft) diameter, 12.89 km (8 mi) long Upper Kotmale Tunnel, the longest excavated tunnel in Sri Lanka, will be used to deliver the water to the powerhouse. The tunnel begins at the dam site, and stretches north at a distance of approximately 7.4 km (4.6 mi) towards PundaluoyaPundaluoya
Pundaluoya is a village in Sri Lanka. It is located within Central Province.-External links:*...
, before stretching a further 5.5 km (3.4 mi) north-west towards Kumbaloluwa and ending up at its powerhouse at the Kotmale River near Niyamgamdora
Niyamgamdora
Niyangandora is a village in Sri Lanka. It is located within Central Province.-External links:*...
, at approximately 07°02′33"N 80°39′23"E, 2 km (1.2 mi) downstream of the confluence of Pundal River and the Kotmale River. Excavation on the tunnel was completed and ceremonially opened by President
President of Sri Lanka
The President of Democratic Socialist Republic of Sri Lanka is the elected head of state and the head of government. The President is a dominant political figure in Sri Lanka. The office was created in 1978 but has grown so powerful there have been calls to restrict or even eliminate its power...
Mahinda Rajapaksa
Mahinda Rajapaksa
Percy Mahendra "Mahinda" Rajapaksa ; ; born November 18, 1945) is the 6th and current President of Sri Lanka and Commander in Chief of the Sri Lankan Armed Forces. A lawyer by profession, Rajapaksa was first elected to the Parliament of Sri Lanka in 1970, and served as prime minister from April 6,...
on the 4th of November, 2010.
Powerhouse
The powerhouse measures 66.3 m (217.5 ft) long, 18.8 m (61.7 ft) wide, and 36.5 m (119.8 ft) tall, and is located underground at NiyamgamdoraNiyamgamdora
Niyangandora is a village in Sri Lanka. It is located within Central Province.-External links:*...
. It has installed electrical capacity of from two turbines
Water turbine
A water turbine is a rotary engine that takes energy from moving water.Water turbines were developed in the 19th century and were widely used for industrial power prior to electrical grids. Now they are mostly used for electric power generation. They harness a clean and renewable energy...
, capable of producing up to of power annually. Water arrives at the powerhouse from the dam via the 12.89 km (8 mi) long Upper Kotmale Tunnel, which then feeds the 793 m (2,602 ft) penstock
Penstock
A penstock is a sluice or gate or intake structure that controls water flow, or an enclosed pipe that delivers water to hydraulic turbines and sewerage systems. It is a term that has been inherited from the technology of wooden watermills....
. The initial 745 m (2,444 ft) of the penstock is single-lane, while the latter 48 m (157 ft) splits into two lanes, feeding the two generators respectively.
The powerhouse consists of the two three-phase vertical-axis Francis turbine
Francis turbine
The Francis turbine is a type of water turbine that was developed by James B. Francis in Lowell, Massachusetts. It is an inward-flow reaction turbine that combines radial and axial flow concepts....
-generators, two three-phase transformer
Transformer
A transformer is a device that transfers electrical energy from one circuit to another through inductively coupled conductors—the transformer's coils. A varying current in the first or primary winding creates a varying magnetic flux in the transformer's core and thus a varying magnetic field...
s, and a 220kV
KV
-In physics and chemistry:* Voltage-gated potassium channel,a large family of potassium channels* Kilovolts , 1000 volts* The rating of RPMs per volt as used in reference to the rotational speed of brushless motors...
Gas Insulator Switchgear
Switchgear
The term switchgear, used in association with the electric power system, or grid, refers to the combination of electrical disconnects, fuses and/or circuit breakers used to isolate electrical equipment. Switchgear is used both to de-energize equipment to allow work to be done and to clear faults...
(GIS) substation. An outdoor switchyard measuring 36.5 m (119.8 ft) by 130 m (426.5 ft) would then connect the powerhouse to the national grid via an 18 km (11 mi) long double-circuit transmission line
Overhead power line
An overhead power line is an electric power transmission line suspended by towers or utility poles. Since most of the insulation is provided by air, overhead power lines are generally the lowest-cost method of transmission for large quantities of electric energy...
which connects the switchyard to the national grid at the existing Kotmale Substation at 07°07′18"N 80°34′51"E. Two megawatts from each of the generators will be utilized to run the Upper Kotmale facility itself, thus the net production will be instead of .
Transmission Line
The 220kV transmission line of the Upper Kotmale Hydro-power Project connects the power station located at Niyamgamdora, Kotmale to the national grid via Kotmale switch yard located in Atabage, Gampola.The line consists of 45 towers and has a length of 15.5km. The double circuit transmission line has a capacity of 220MW
MW
-Transportation:* Maintenance of way, railroad upkeep* Maya Island Air IATA airline designator-Games:* Mafia Wars, a game on Facebook* MechWarrior, a profession in the fictional universe of BattleTech...
per circuit.
Social and environmental impact
The construction of the dam, tunnel, and powerhouse, required the relocation of families from 495 houses. New homes were built away from the site with access to vital facilities such as water and power. The relocated families are provided with concessionary loans to start new self-employment ventures, while additional facilities such as the Talawakele Central College, places of worship, a cinema hall, a library, and a community centre, are being established.Similar most other dam's impacts on rivers around the world, the Upper Kotmale Dam will periodically stop the St. Clair's Falls, located 2.2 km (1.4 mi) downstream of the dam, and a further 2.9 km (1.8 mi) of the Kotmale River downstream of St. Clairs Falls, before the river is restored by water from the Devon River, the river forming the picturesque Devon Falls
Devon Falls
Devon Falls is a waterfall in Sri Lanka, situated 6 km west of Talawakele, Nuwara Eliya District on A7 highway. The falls is named after a pioneer English coffee planter called Devon, whose plantation is situated nearby the falls. The Waterfall is 97 meters high and ranked 19th highest in the...
. As ordered by the Government Extraordinary, the St. Clair's waterfall will maintain a continuous flow of 47250 cubic metre of water for 10 hours and 30 minutes daily, between sunrise and sunset.
See also
- Energy in Sri LankaEnergy in Sri LankaEnergy sources in Sri Lanka consists primarily of hydro, coal, fossil fuel and biomass, with sources such as photovoltaics and wind power in early stages of development...
- Kotmale DamKotmale DamThe Kotmale Dam is a large hydroelectric and irrigation dam in Kotmale, Sri Lanka. The dam generates power from three turbines, totalling the installed capacity to , making it the second largest hydroelectric power station in Sri Lanka...
- List of dams and reservoirs in Sri Lanka
- List of power stations in Sri Lanka