Three Gorges Dam

The Three Gorges Dam is a massive gravity dam located on the mainstream of the Yangtze River, at the town of Sandouping in the city of Yichang in China’s Hubei province. The Three Gorges Dam is the largest power station in China and since 2012, it is also considered the largest hydroelectric power station in the world in terms of both total installed capacity and annual average power generation volume. Besides producing electricity, the main purpose of constructing the Three Gorges Dam was to reduce the potential for floods as well as increase the shipping capacity of the Yangtze River.

About the Three Gorges Dam

Three Gorges Dam, China
View of the Three Gorges Dam on the Yangtze River in China. 

Located in the Xilingxia Gorge of the Yangtze River, the Three Gorges Dam Project is under the management of the China Three Gorges Corporation. The Three Gorges Dam has a length of 2,335m and the top of the dam is situated at an elevation of 185m. The base of the dam has a width of 115m while the crest has a width of 40m. It has been estimated that the entire project had used 27.2 million cubic meters of concrete, 463,000 tonnes of steel and had moved 102.6 million cubic meters of earth.

Three Gorges Dam Reservoir
The Three Gorges Dam Reservoir in China. 

The construction of the Three Gorges Dam led to the creation of the Three Gorges Reservoir, which covers a total area of 1,045 sq. km, and has a length of 660km and a width of 1.12km. Extending about 600km upstream from the dam, the reservoir holds about 39.3 cubic kilometers of water. The Three Gorges Dam contains 34 generators and two power plant generators. Of these 34 generators, there are 32 principal generators, each of which has a capacity of 700 MW and each of the two power plant generators has a capacity of 50MW.  Of the 32 main power generators, 14 generators are placed on the northern side of the dam, and 12 generators are placed on the southern side of the dam. Another six generators have been placed in the project’s underground power plant. In 2012, all the 32 hydro units of the Three Gorges Dam were commissioned to produce 22,500MW of hydroelectricity, making it the world’s largest hydroelectric power plant in terms of electricity production. In 2018, the annual electricity generation of the Three Gorges Dam was 101.6 TWh. This generation of electricity however depends upon the amount of rainfall in the Yangtze River Basin. In 2020, due to excessive monsoon rainfall, the dam’s yearly electric production was about 112 TWh, which broke the world record of 103 TWh that was set by Brazil’s Itaipu Dam in 2016.

It has been estimated that by the end of 2008, the government had already spent about 148.365 billion yuan on the Three Gorges Dam Project, of which 15.195 billion yuan was spent on financing, 68.557 billion yuan on the relocation of the affected individuals, and 64.613 billion yuan was spent on constructing the project. The Government however recovered the full cost of the Three Gorges Dam project by December 2013. It was recorded in 2011, that even when fully functional, the Three Gorges Dam supported only about 1.7% of China’s total demand for electricity.

Environmental Impacts

Since the completion of the Three Gorges dam project in 2008, more than 1.3 million people have been relocated and 140 towns, 1350 villages, and 13 cities were submerged. It is also believed that the bank collapses and major landslides upstream from the dam may relocate more than 100,000 people in the coming years. As per geologists, the dam could also trigger severe earthquakes as the reservoir is located on the Jiuwanxi and Zigui-Badong faults. The Three Gorges Dam has also threatened the biodiversity in the region leading to a reduction in the forest cover in turn affecting all the flora and fauna of the region.

Construction History

Ships rising in the locks at Three Gorges Dam
Ships rising in the locks in Three Gorges Dam, China. 

In 1919, a plan to construct a massive dam across the Yangtze River was put forth by the Chinese Statesman Sun Yat-sen, who also served as the provisional first President of the Republic of China. Sun Yat-sen believed that it was possible to construct a dam downstream of the Three Gorges, that could generate 22GW of hydroelectric power. The Nationalist Government under Chiang Kai-shek in 1932, started its preliminary work on the construction of a dam in the Three Gorges region. John L. Savage who served as the head design engineer in the United States Bureau of Reclamation surveyed the area in 1944 and submitted a proposal for constructing a dam as a part of the Yangtze River Project. However, the work was stalled by the government in 1947 amid the Chinese Civil War. After the Chinese Communist Revolution in 1949, Mao Zedong, the architect of China’s Great Leap Forward and Cultural Revolution, supported the project and also wrote a poem about his fascination for a dam on the Yangtze River. The construction of the dam was finally approved by the National People’s Congress in 1992 and the construction work began on December 14, 1994. The construction of the body of the dam was completed in 2006 and the entire project became fully functional on July 4, 2012. Since then, the Three Gorges Dam has been the world’s largest hydroelectric plant with a total generating capacity of 22,500MW.