Victoria Dam is an arch dam

Arch dam

An arch dam is a type of dam that is curved and commonly built with concrete. The arch dam is a structure that is designed to curve upstream so that the force of the water against it, known as hydrostatic pressure, presses against the arch, compressing and strengthening the structure as it pushes...

 located 130 mi (209 km) upstream of the Mahaweli River's mouth and 4 mi (6 km) from Teldeniya

Teldeniya

Teldeniya is a village in Sri Lanka. It is located within Central Province.-External links:*...

. Its main purposes are irrigation and hydroelectric power production. It is the tallest dam in 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...

, and supports a power station, the largest hydroelectric power station in the country. Construction of the dam commenced in 1978, and was ceremonially completed by former 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...

 Jayewardene

Junius Richard Jayewardene

Junius Richard Jayewardene , famously abbreviated in Sri Lanka as JR, was the first executive President of Sri Lanka, serving from 1978 till 1989. He was a leader of the nationalist movement in Ceylon who served in a variety of cabinet positions in the decades following independence...

 in April 1985.

History

The Victoria Dam was constructed under the Accelerated Mahaweli Development Programme (AMDP). The project had been in planning for years but was accelerated in 1977 to address economic difficulties within the country. The plan is designed to irrigate 365000 ha (901,934 acre) of land and provide 600 MW of electricity. The Victoria Dam was originally proposed in 1964 after studies were completed by Canada's Huntings Technical Services and a team from the United Nations Development Program—Food and Agriculture Organization

Food and Agriculture Organization

The Food and Agriculture Organization of the United Nations is a specialised agency of the United Nations that leads international efforts to defeat hunger. Serving both developed and developing countries, FAO acts as a neutral forum where all nations meet as equals to negotiate agreements and...

 (UNDP-FAO). Construction of the dam was inaugurated on 14 of August 1978, by the former President Jayewardene

Junius Richard Jayewardene

Junius Richard Jayewardene , famously abbreviated in Sri Lanka as JR, was the first executive President of Sri Lanka, serving from 1978 till 1989. He was a leader of the nationalist movement in Ceylon who served in a variety of cabinet positions in the decades following independence...

 with implementation of the main structures beginning in 1980. Its completion was marked by a ceremony on 12 April 1985. Construction of the dam

Dam

A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...

 and tunnel was completed by the British Joint Venture of Balfour Beatty and Edmund Nuttall, while Costain International carried out the construction of the power station

Power station

A power station is an industrial facility for the generation of electric energy....

. The dam resettled about 30,000 people — four times the estimate.

Dam and powerhouse

The dam measures 122 m (400 ft) tall, with a crest length of 520 m (1,706 ft), crest width of 6 m (20 ft), and a base width of 25 m (82 ft). The dam creates the Victoria Reservoir, which has a surface area of 22.7 square kilometre, gross storage capacity of 722000000 cubic metre, and a catchment area of 1869 square kilometre.

Water from the dam is fed to the powerhouse at 07°12′00"N 80°48′21"E via a 5646 m (18,524 ft) long tunnel, which houses three 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....

s of 6.2 m (20.3 ft) diameter. These penstocks created a net head

Hydraulic head

Hydraulic head or piezometric head is a specific measurement of water pressure above a geodetic datum. It is usually measured as a water surface elevation, expressed in units of length, at the entrance of a piezometer...

 of 190 m (623 ft), feeding three 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...

, which are capable of generating up to of electrical energy annually.

Th dam consists of eight spillway

Spillway

A spillway is a structure used to provide the controlled release of flows from a dam or levee into a downstream area, typically being the river that was dammed. In the UK they may be known as overflow channels. Spillways release floods so that the water does not overtop and damage or even destroy...

s, each with a width and height of 12.5 m (41 ft) and 6.5 m (21.3 ft), which automatically opens when water levels are high. The dam's gates, which needs power only to close, won an award for "Innovative Design in Civil Engineering" by the Institution of Civil Engineers

Institution of Civil Engineers

Founded on 2 January 1818, the Institution of Civil Engineers is an independent professional association, based in central London, representing civil engineering. Like its early membership, the majority of its current members are British engineers, but it also has members in more than 150...

. The total effective width of the spillways is 100 m (328 ft), allowing a maximum discharge of 8200 m3/s. Two additional low-level sluice

Sluice

A sluice is a water channel that is controlled at its head by a gate . For example, a millrace is a sluice that channels water toward a water mill...

s at the base of the dam allows the purging of accumulated silts behind the dam.

See also

• List of dams and reservoirs in Sri Lanka
• List of power stations in Sri Lanka
• List of rivers in Sri Lanka