Three Gorges Dam
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What is the Three Gorges Dam?
The Three Gorges Dam is a dam on the Yangtze River in China's Hubei province, west of Yichang. Officially started in 1994, it became the world’s largest dam structure upon completion in 2006 and reached full generating capacity in 2012.
The dam facilitates oceangoing freighters' navigation and generates hydroelectric power. While intended to provide flood protection, its effectiveness is debated. The Three Gorges Dam has been a controversial project, resulting in the displacement of approximately 1.3 million people and the destruction of natural features as well as architectural and archeological sites. The dam's reservoir has also been blamed for an increase in landslides and earthquakes in the region.
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Where is the Three Gorges Dam located?
The Three Gorges Dam is located on the Yangtze River (Chang Jiang), just west of Yichang in Hubei province, China. About 25 miles (40 km) upstream from Yichang, the dam sits at the Three Gorges section of the Yangtze, within the Xiling Gorge and southern Daba mountain ranges to the west.
Construction officially began in 1994, and when completed in 2006, it was the largest dam structure in the world. The dam facilitates navigation for oceangoing freighters and generates hydroelectric power. It also aimed to provide flood protection, though its effectiveness is debated. The dam has a maximum height of 185 metres (607 feet) and a length of 2,335 metres (7,660 feet).
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Why was the Three Gorges Dam built?
The Three Gorges Dam on China's Yangtze River was built to manage disastrous flooding, facilitate inland trade, and provide power for central China. Construction officially began in 1994, and reached full generating capacity in 2012. The dam is a straight-crested concrete gravity structure, 2,335 metres long with a maximum height of 185 metres.
The dam has the capacity to generate 22,500 megawatts of electricity, making it the most productive hydroelectric dam in the world. The dam also allows oceangoing freighters to navigate 2,250 km inland from Shanghai to Chongqing.
However, the dam has faced criticism. Its construction led to the displacement of at least 1.3 million people, the destruction of natural features, and the obliteration of architectural and archeological sites. There are also concerns that the reservoir could trigger earthquakes and landslides.
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How does the Three Gorges Dam produce electricity?
The Three Gorges Dam produces hydroelectric power using 32 turbine generator units, giving it a generating capacity of 22,500 megawatts. As water flows through the dam, it spins these turbines, which are connected to generators that convert the mechanical energy into electricity. Limited power production started in 2003 and increased until 2012, when all turbine generators became fully operational. In 2020, the dam set a world record for annual power generation volume at 111.88 terawatt hours.
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What are some benefits of the Three Gorges Dam?
The Three Gorges Dam on China's Yangtze River provides several benefits:
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Hydroelectric power The dam has the capacity to generate 22,500 megawatts of electricity, and in 2020, the hydroelectric plant produced a world record of 111.88 terawatt hours.
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Navigation The dam has created a deepwater reservoir, which allows oceangoing freighters to navigate 2,250 km inland from Shanghai to Chongqing. Vessels navigate the dam and reservoir using five-tier ship locks and a ship lift.
The dam was also intended to protect millions of people from periodic flooding, but its effectiveness has been debated.
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What are some environmental and social impacts of the Three Gorges Dam?
The Three Gorges Dam on the Yangtze River has had considerable environmental and social effects. The dam's construction led to the displacement of at least 1.3 million people, the destruction of natural features, and the obliteration of rare architectural and archeological sites.
The dam's reservoir is blamed for an increase in landslides and earthquakes in the region. Critics have expressed concerns that human and industrial waste would pollute the reservoir and that the large amount of water impounded could trigger seismic events. There are also fears that the waters downstream from the dam, now largely free of their silt burden, will erode surrounding banks rather than build them up and may cause much land degradation.
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Three Gorges Dam, dam on the Yangtze River (Chang Jiang) just west of the city of Yichang in Hubei province, China. When construction of the dam officially began in 1994, it was the largest engineering project in China. At the time of its completion in 2006, it was the largest dam structure in the world. The dam and accompanying hydroelectric plant were built in phases and over the course of many years. It reached its full generating capacity in 2012. The dam allows the navigation of oceangoing freighters and generates hydroelectric power. It was also intended to provide protection from floods, but efficacy on this point is unclear and has been debated.
While the construction of the Three Gorges Dam was an engineering feat, it has also been fraught with controversy: construction of the dam caused the displacement of at least 1.3 million people and the destruction of natural features and countless rare architectural and archaeological sites. The dam’s reservoir is blamed for an increase in the number of landslides and earthquakes in the region.
Physical description and capacity of the Three Gorges Dam
A straight-crested concrete gravity structure, the Three Gorges Dam is 2,335 meters (7,660 feet) long with a maximum height of 185 meters (607 feet). It incorporates 28 million cubic meters (37 million cubic yards) of concrete and 463,000 metric tons of steel into its design. Submerging large areas of the Qutang, Wu, and Xiling gorges for some 600 km (375 miles) upstream, the dam has created an immense deepwater reservoir (storage capacity, 39.3 billion m3) allowing oceangoing freighters to navigate 2,250 km (1,400 miles) inland from Shanghai on the East China Sea to the inland city of Chongqing. Navigation of the dam and reservoir is facilitated by the five-tier ship locks at both ends of the complex, which allow vessels of up to 10,000 tons to navigate past the dam, and a ship lift, which allows vessels of up to 3,000 tons to bypass the ship locks and travel past the dam more quickly. At the time of its completion in late 2015, the lift, which was 120 meters (394 feet) long, 18 meters (59 feet) wide, and 3.5 meters (11 feet) deep, was the largest ship lift in the world.
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- Location and river system: Yangtze River (Chang Jiang), near Yichang, Hubei Province, China
- Structural type: Straight-crested concrete gravity dam
- Dimensions: Length, 2,335 meters (7,660 feet); height, 185 meters (607 feet)
- Reservoir storage capacity: 39.3 billion m3
- Hydroelectric output: 22,500 megawatts installed capacity; generated a world-record 111.88 terawatt hours of electricity in 2020
- Construction timeline: Construction commenced in 1994, completed in 2006, reached full generating capacity in 2012
- Primary functions and purpose: Flood moderation for the Yangtze basin; facilitation of inland navigation and trade; power generation for central China
Limited hydroelectric power production began in 2003 and gradually increased as additional turbine generators came online over the years until 2012, when all of the dam’s 32 turbine generator units were operating. Those units, along with 2 additional generators, gave the dam the capacity to generate 22,500 megawatts of electricity, making it the most productive hydroelectric dam in the world. In 2020 the hydroelectric plant produced 111.88 terawatt hours, setting a new world record for annual power generation volume.
The dam also was intended to protect millions of people from the periodic flooding that plagues the Yangtze basin, although just how effective it has been in this regard has been debated. In 2020 China experienced its heaviest floods in more than three decades, and the dam’s reservoir neared maximum capacity, reaching the highest levels since it began retaining water in 2003. Officials said that the dam reduced damage and loss of life from the floods, while critics asserted that the heavy floods served to highlight the limitations of the dam as an effective flood-control tool.
