How it began
The Nurek Dam was built by the Soviet Union on the Vakhsh River in what was then the Tajik Soviet Socialist Republic, in a deep gorge about 75 kilometers east of Dushanbe. Construction began in 1961. The first generating unit was commissioned in 1972 and the last in 1979, and the whole project was completed in 1980. On completion it was the tallest dam in the world. A town also called Nurek was built nearby to house engineers and plant workers.
How it works
Nurek is an embankment dam: a mound of rock and earth about 300 meters high and 700 meters long, with a volume of 54 million cubic meters, built around a central impermeable core that stops water seeping through. Behind it the reservoir stretches more than 70 kilometers, covers 98 square kilometers and holds 10.5 cubic kilometers of water.
Water drives nine Francis turbine generators. They were first rated at 300 megawatts each and were refitted between 1984 and 1988 to 335 megawatts each, for an installed capacity of 3,015 megawatts.
What changed first
An estimated 5,000 people were resettled from the area flooded by the reservoir. The stored water was put to use for farming as well as power: a 14 kilometer tunnel carries irrigation water to about 700 square kilometers of land in the Dangara area. Filling the reservoir is also suspected of having triggered earthquakes, and Nurek became a studied case of reservoir-induced seismicity.
What lasted
Nurek became the backbone of Tajikistan's electricity supply after independence. In 1994 it made up most of the country's 4 gigawatts of hydropower capacity, which met about 98 percent of national electricity needs. The World Bank says the plant generates about half of the energy demanded in Tajikistan each year, and another recent estimate puts its share at 70 percent. The dam also held the height record for more than three decades, until China's Jinping-I arch dam was completed in 2013. Guinness World Records lists Nurek as the tallest embankment dam.
Where it stands today
After four decades of operation the plant's usable capacity had fallen from over 3,000 megawatts to about 2,320 megawatts. A two-phase rehabilitation financed by the World Bank, the Asian Infrastructure Investment Bank and other lenders is replacing generating units and improving dam safety. The dam is owned and operated by the state utility Barqi Tojik. Upstream on the same river, the Rogun Dam is under construction and may exceed Nurek in height when finished.
