Three Gorges Dam (China)

Summary: The Three Gorges Dam is one of the largest hydroelectric dams ever constructed. Located in central China on the Yangtze River, the dam has made a major contribution to China's electric generating capacity in lieu of coal, which once accounted for about 80 percent of electric generation. The dam has also raised environmental concerns, including the possibility of major landslides and even earthquakes as the level of the reservoir is adjusted to account for flood season. Originally proposed in 1919, construction began in 1994. The dam’s body was completed in 2006, the power plant in 2012, and the boat lift in 2015. The projected cost of the dam was estimated at $24 billion but ended up costing $37 billion. The dam has a power capacity of 22,500 megawatts—many times the capacity of the Hoover Dam, which can produce 2,080 megawatts of power.

The Three Gorges project has generated significant controversy, both domestically and in the ongoing debate over energy, the environment, and the welfare of the people of China. Though the dam is wholly domestic and has no direct impact on other countries, it had significant impact on China and many citizens opposed it. It was a topic of criticism and protest, including during the 1989 Tiananmen Square demonstrations in Beijing. On one hand, the dam promised to generate electricity from a clean, renewable source—the flow of the Yangtze—that would otherwise be supplied by coal-fired plants, which once accounted for about 80 percent of China's growing demand for electricity, and their associated emissions of carbon dioxide and sulfur.

On the other hand, environmentalists and geologists argue that the size of the dam, which created a reservoir 370 miles (595 kilometers) long and with a surface area of 400 square miles (1,036 square kilometers), could have several environmental impacts, ranging from generating earthquakes to exacerbating the growth of bacteria downstream that could threaten some species of fish.

History and Projected Role. Harnessing the flow of the Yangtze to generate electricity has been a long-standing idea in China, dating to nationalist leader Sun Yat-sen in 1919. Engineers began planning in 1954. Implementation of the plans was long delayed, first by economic setbacks during the failed Great Leap Forward campaign and later during the political and social upheavals of the Cultural Revolution in the late 1960s and early 1970s.

Prior to the dam, China's demand for energy was rapidly increasing due to population growth. For example, China's energy use increased by 57 percent from 2005 to 2011, and that growth has continued each year. The amount of skilled labor and resources, though, were scarce.

In 2023, China claimed to produce about half of its electricity from renewable resources, primarily hydropower. Much of this came from dozens of dams built on the upper Yangtze. The dams have the power to create electricity production equivalent to 50 million tons of coal per year and, therefore, are more energy efficient.

The Project. The dam is located between high cliffs in a spot called Three Gorges, an area that begins in Sichuan Province and ends in Hubei Province, over a distance of about 120 miles in central China. (The three gorges are named Qutang, Wuxia, and Xiling.) The dam itself stretches across a narrow canyon, creating a reservoir 370 miles long and about with a surface area of 400 square miles, or 1,036 square kilometers (roughly twice the width of the natural river channel).

In June 2003, the reservoir was filled to a depth of 445 feet (136 meters). Three years later, in September 2006, the depth was increased to 512 feet (156 meters). The final depth reached 574 feet (175 meters).

Authorities periodically lower the depth to account for flood seasons, dry seasons, and navigation.

Environmental Impact. So far, the Three Gorges Dam has been implicated in major environmental situations:

Landslides. Only one month after the dam was filled to its initial depth, an estimated 700 million cubic feet (198,218 cubic meters) of rocks slid into the Qinggan River, which flows into the Yangtze, creating waves up to sixty feet (18 meters) high. Fourteen people died. Dozens of other landslides were recorded along the banks of the Yangtze. In one case, a landslide near the entrance to a railway tunnel caused a landslide onto a highway, burying a bus and killing thirty people. According to geologists, the landslides are triggered when water seeps into soil at the base of rocky cliffs, destabilizing them and making them prone to landslides. Changes in water pressure caused by periodically raising and lowering the depth of the reservoir also destabilize the land.

Earthquakes. A phenomenon called seismicity may result in earthquakes caused by the pressure of the huge reservoir. The Three Gorges Reservoir sits on top of two faults, and geologists fear the reservoir's weight and shifting pressure could trigger quakes. In the first seven months after the reservoir's level was raised in September 2006, 822 tremors were recorded in the area, though none were damaging. Some geologists blame the earthquakes near the Oroville Dam in northern California in 1985 on this phenomenon. In 2013, a 5.1 magnitude earthquake occurred in the area of the Three Gorges.

Potential Collapse. Critics of the dam, including scientists, are concerned that the dam could collapse and cause catastrophic damage, be it from an earthquake, landslide, other natural causes, or from cracks and substandard concrete and design.

Impact on Biodiversity. The impact of the reservoir-notably the reduced flow of the Yangtze-is thought to affect areas downstream from the dam, especially near the mouth of the river where it flows into the South China Sea at Shanghai. The altered flow of the river may change a delicate pattern of lakes near the river's mouth, where several unique species of fish have evolved, according to some biologists. Some fish species have also been threatened by over-fishing in the densely populated region. In early 2008, published studies said the depth of the Yangtze was the lowest measured in 142 years. Chinese authorities acknowledged that the dam had reduced water flow by 50 percent. This reduced flow, blamed on the dam, results in salt water from the South China Sea flowing farther upstream during high tides. In turn, biologists have recorded a rise in the number of jellyfish competing for food with fish in the river. Biologists have also recorded an increased incidence of schistosomiasis, a blood parasite transmitted by snails and contracted by swimming in contaminated fresh water where infected snails have released larvae. Decreased river flow is blamed for allowing an increase in the population of snails.

However, flooding can also affect the biodiversity. The 2020s saw instances of flooding both in the dam basin and in nearby bodies of water. In July 2024, the dam reservoir reached 528.5 feet (161 meters), the highest level ever recorded for that month. The flooding inundated large areas of natural habitats, disrupted the migratory patterns of fish species, and altered the river flow, which led to significant declines in both aquatic and terrestrial wildlife populations, including endangered species like the Baiji dolphin and the Chinese river sturgeon.

Social-Political Impact. Construction of the dam and the resulting reservoir has caused 1.4 million people to be relocated from two cities and 116 towns on the banks of the Yangtze. In 2007, Prime Minister Wen Jiabao reported that 22.9 million people had been relocated to make room for all the country's hydroelectric projects, including Three Gorges.

The Three Gorges Dam also underscores the complexity of lessening China's dependence on coal to generate electricity in an era when "going green"—or failure to do so—could have international trade implications. Although China claims that the environmental impact of the dam does not affect other countries, the importance of hydropower in lieu of carbon-based fuels could have international implications.

Bibliography

Carney, Trent M. “China’s Three Gorges Dam: Development, Displacement, and Degradation.” Nebraska Anthropologist, vol. 29, 2021, pp. 20-27. University of Nebraska - Lincoln, digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1193&context=nebanthro. Accessed 4 Oct. 2024.

López-Pujol, J., and M. X. Ren. "Biodiversity and the Three Gorges Reservoir: A Troubled Marriage." Journal of Natural History, vol. 43, no. 43–44, 2009, pp. 2765–2786. Taylor & Francis Online, doi.org/10.1080/00222930903220010. Accessed 4 Oct. 2024.

Toy, Mary-Anne. “Three Gorges Dam ‘Could Be Huge Disaster.’” The Age, 27 Sept. 2007, p. 12. EBSCOhost, search.ebscohost.com/login.aspx?direct=true&db=apr&AN=SYD-5GPQA5J9MT41ECFMXAXH&site=ehost-live. Accessed 4 Oct. 2024.

Qing, Dai, and Lawrence R. Sullivan. “The Three Gorges Dam and China’s Energy Dilemma.” Journal of International Affairs, vol. 53, no. 1, Fall 1999, p. 53. EBSCOhost, search.ebscohost.com/login.aspx?direct=true&db=f6h&AN=2482770&site=ehost-live. Accessed 4 Oct. 2024.

Sheridan, Michael. “The Great Wall of Water.” World Today, vol. 69, no. 11, Dec. 2013, pp. 36–39. EBSCOhost, search.ebscohost.com/login.aspx?direct=true&db=f6h&AN=92896363&site=ehost-live. Accessed 4 Oct. 2024.

Wilmsen, Brooke, et al. “Development for Whom? Rural to Urban Resettlement at the Three Gorges Dam, China.” Asian Studies Review, vol. 35, no. 1, Mar. 2011, pp. 21–42. EBSCOhost, doi.org/10.1080/10357823.2011.552707. Accessed 4 Oct. 2024.