The gigantic Three Gorges will be dammed for the second time in mid or late November, Guo Shuyan, director of Three Gorges Project Construction Committee, said Tuesday.
The Three Gorges Project Construction Committee is a body under the State Council, China's cabinet, and is in charge of the construction of the Three Gorges dam and reservoir.
The completed sections of the dam, the world's largest, were left unscathed by nearly the worst ever floods on China's longest river, the Yangtze, this summer.
The Yangtze will be dammed again for the third-phase construction on the 665-meter section to complete the 2,309-meter-long dam, the country's largest water conservancy project on the middle reaches of the Yangtze River.
Situated in the western Yichang area, central China's Hubei Province, the project consists of a 2,309-meter-long by 185-meter-high dam and 26 generating units with a combined capacity of 18.2 million kilowatts.
Upon completion in 2009, the project will be able to generate 84.7 billion kilowatts of electric power annually. Its permanent locks will allow ships of more than 10,000 DWT (dead weight tonnage) to pass. By the end of August, approximately 70 percent of the dam had been completed. According to the design plan, the dam should be able to withstand the heaviest floods which take place once every 10,000 years.
During the flooding, the cofferdams were demolished to test the dam's water tightness, and results proved to be very satisfactory.
The cofferdams had been built to allow normal navigation during the 17-year construction period. When the mainstreams of the Yangtze River were blocked in November 1997, the cofferdams were constructed on the river's left bank to form a pit in which the 1,600-meter left section of the dam and a powerhouse were built.
The second damming will block the water diversion canal, 3.7 kilometers long and 350 meters wide, which was built to serve as the only navigable channel for ships and boats from 1997 to 2002.
The second damming is more technologically demanding considering it will be conducted on the bare rock riverbed of the canal with stronger currents, according to Guo.
The damming date is dependent on water changes, but was best during a thin flow period, Guo added.
So far sand and rocks for the damming have been set in place.
The project is expected to reach the next year's three scheduled goals -- water storage, navigation and power generation.
(People’s Daily September 11, 2002)
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