Building the Three Gorges Dam
A dam across the Yangtze was first proposed by Dr. Sun Yat-sen in 1919.
A serious survey was made by Dr. J. Lucian Savage, supervisor of the design of the Hoover dam, in 1944 while the Japanese still occupied much of eastern China.
The government approved construction in 1994 and the dam was completed in July of 2012, except for the ship lift that remains under construction. (The ship lift is for small vessels.)
The dam has two purposes:
- Flood control to eliminate the devastating floods that killed hundreds of thousands over the past century.
- Generation of electricity.
Maintaining barge traffic in the Yangtze was a major concern and the site selected for the dam included an island that allowed construction to proceed in two phases. Roughly two thirds of the river north of the island was blocked with a cofferdam, which allowed construction of the dam and locks to proceed while the river continued to flow south of the island, thereby permitting barge traffic to continue unabated.
After the dam and locks were completed north of the island, the section of the river south of the island was blocked with a cofferdam which allowed the remainder of the dam to be built.
The locks permit barges to transit the dam site in both directions, thereby allowing for continued flow of barge traffic along the river when the south side of the river was blocked with a cofferdam and now that the dam has been completed.
Picture Courtesy of The Magnificent Three Gorges Project edited by Li jinlong and Yi chang
The completed dam is shown here. The red crane structures on the dam are for opening the sluice gates. There are 14 generators, rated 700 MW in the north section of the dam, 12 more in the south section and an additional 6 located at the extreme south section of the dam.
There has been considerable criticism surrounding the Three Gorges Dam. Criticism has primarily focused on environmental issues, the forced resettlement of 1.3 million people and the flooding of archeological sites.
The resettlement involved relocating people from old cities that would be flooded, to new cities built to accommodate the people being displaced.
For the most part, people moved into new buildings, such as those shown here, in a city built directly above the old city, now under water. Younger people often relocated to the larger cities, such as Shanghai.
While many archeological sites were flooded, the pagoda at Shibaozhai was protected by a cofferdam.
This year has demonstrated the value of the Three Gorges Dam for flood control. The water flow this year has reportedly exceeded the heaviest flows in the year of earlier floods, and few, if anyone, has been killed by flooding.
The Three Gorges Dam is also providing needed electricity for most of the region surrounding the Yangtze River. More about this later.
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