Three Gorges Dam Facts: 8 Things You Need to Know
1. Three Gorges Dam is the world’s largest dam.
This is a basic Three Gorges Dam fact. The dam is the largest concrete gravity dam around the world with a length of 2,335 meters (2,553.6 yd) and a biggest height of 185 meters (607 ft.). The double-line five-grade ship lock is also the world’s largest, which is 6.4 kilometers (4 miles) long on the whole, including 1.6 kilometers (1 mile) long main part and 4.8 kilometers (3 miles) long approach channels. The height difference of ship lock is 113 meters (370.7 ft.), that’s to say, the ship has to climb over a height equally to a 40-storey building to pass through the dam.
2. It is the largest hydroelectric station in the world.
Three Gorges Dam became the largest hydroelectric power station and clean energy production base worldwide since 2012. It is also a key water control project with best comprehensive benefits all over the world so far. Except for the effects of flood control and shipping, the installed generating sets have a combined capacity of 22.5 million kWh, with the annual energy output of more than 100 billion kWh, both of which ranks the first in the world. The electricity generated there are transferred to Henan, Hubei, Hunan, Jiangxi, Chongqing, Anhui, Jiangsu, Zhejiang, Shanghai and Guangdong, etc.
3. Three Gorges Project had been planned for over 100 years! Can you believe it?
As early as 1918, Sun Yat-sen, the great leader of China’s revolution in modern times, had come up with the idea to build a dam in Three Gorges, in order to improve the shipping route and store water resources of Yangtze River. Since 1955, the survey, research and planning work of Three Gorges project were fully carried out. In 1970, Gezhouba Dam was approved to be built, from which the experience of building dam in Yangtze River Three Gorges was gathered. In 1992, the Three Gorges Dam construction was legally approved. In 1994, the project officially started to be built. In 2009, the project was completed and started to work.
4. The greatest function of Three Gorges Dam is flood control.
A fact of Three Gorges Dam you may not know before is that its first important work is flood control to save people’s life. Its flood control capacity is 22.15 billion cubic meters, and 27,000-33000 cubic meters flood can be reduced per second. Before Three Gorges Dam was built, there was a flood every decade in past 2,000 years. Now, guarded by Three Gorges Dam, a hundred-year flood would do nothing to people; when a thousand-year flood occurs, the flood flow can be controlled within 80,000 cubic meters per second in Hubei, which ensures the flood will not become a devastating disaster.
Benefits from Three Gorges Project
5. How long did it take to build the dam? 17 years!
It has taken 17 years to finish the construction of the whole Three Gorges Dam project from 1992 to 2009, which includes three stages.
The first stage took five years from 1992 to 1997 till the success of river closure. During this period, the cofferdam construction and the excavation of a diversion channel were finished, and some preparation work was also completed. Meanwhile, a temporary ship lock on the left bank of the river was constructed.
The second stage lasted six years from 1998 to 2003, when the second-staged cofferdam construction was undertaken, at the same time the permanent ship lock was constructed. The power station construction and the installation of machinery on the left bank were also completed. At the end of this period, the reservoir can store a certain amount of water, the first-batch generation unit could produce electricity power and the navigation was realized.
The third stage of the project began in 2003 and completed in 2006. The installation of all machinery, the whole construction of the power station and the dam were finished.
Schedule of Three Gorges Dam Project
6. How much did it cost to build the Three Gorges Dam?
The static investment of Three Gorges Dam project was ¥ 135 billion (US$ 20 billion), and the total investment reached ¥ 249 billion (US$ 37 billion), mainly including ¥ 87.36 billion (US$ 12.7 billion) for project construction, ¥ 85.65 billion (US$ 12.5 billion) for the resettlement of over 1.2 million people in inundated areas, and the ¥ 34.86 billion (US$ 5.1 billion) for the construction of power transmission and transformation.
Up to 2018, the accumulated income from Three Gorges Dam had reached ¥ 300 billion (US$ 43.7 billion), to the exclusion of a large number of income from tourism. The operating company of Three Gorges Hydropower Station had gained income of ¥ 51.2 billion (US$ 7.5 billion) and a retained profits of ¥ 22.6 billion (US$ 3.2 billion) in the year of 2018.
Three Gorges Dam Cost: How much did it cost to build such a huge project?
7. 1.2 million people were relocated for the construction of the dam.
Three Gorges Reservoir inundated a large area of 79,000 square kilometers (30,502 square miles) in Chongqing and Hubei, covering cultivated land of 194,000 hectare (47,939 acres), 2 cities, 11 county-level towns and 114 small towns where more than 1.2 million people lived. According to the migration fact of Three Gorges Dam construction, 115,600 people were resettled before 1997, another 532,100 people from 1998 to 2003, 349,800 people again from 2004 to 2006, and more 211,300 people from 2007 to 2009. Some people were relocated in neighboring towns or cities, while more people had to move to other parts of China, including Sichuan, Jiangsu, Zhejiang, Shandong, Guangdong, Shanghai, Fujian, Anhui, Jiangxi and Hunan provinces.
Problems Caused by Three Gorges Dam
8. Huge Difficulty in Damming the Mighty Yangtze River
It is not easy to dam the Yangtze River because of very large volume of runoff and quite wide inundated area. In the beginning, a cofferdam was built on the right bank, at the same time, temporary and permanent ship locks were constructed on the left bank. When the temporary ship lock was finished, the second river closure began. The cofferdam in right bank was dismantled and the main stream of Yangtze River was cut off, where the spillway and left hydroelectric dam body were constructed. After these constructions were done, the cofferdam in main stream was dismantled and another cofferdam was built on right bank again. When the right hydroelectric dam body was constructed, the cofferdam was removed. In such a complex method, the construction of magnificent Three Gorges Dam was finished.
Read more: Yangtze River Dam – 5 Secrets You don’t Know