The second damming of the Yangtze River for the world's largest water conservancy project will be done on November 6, about 10 days ahead of time, the builder of the project have announced.
Current favorable hydrological and meteorological conditions are the main factors behind pushing forward the damming, said the China Yangtze River Three Gorges Project Development Corporation.
The damming is to cut the man-made diversion channel, built for the passage of ships during the second-phase construction of the Three Gorges Project, a project for permanently harnessing the Yangtze.
Professor Ge Shouxi with the Yangtze River Water Resources Committee heralded the decision as being scientific and based on the actual situation. Damming of the canal was originally set for mid-November.
To successfully dam the man-made canal, water flow needs to slow to 10,300 cubic meters per second. Previous hydrological records suggested mid-November as the only possible time the water flow would meet the requirements.
However, by October 31, water flow was 9,050 cubic meters per second, down from 11,600 cubic meters per second on October 25, and is expected to continue slowing as a result of a drop in the volume of water from the upper reaches of the Yangtze and expected less rainfall on the upper reaches of the river, said Professor Ge.
Ge believed that the water level of the Yangtze at the Three Gorges Project site would not rise within one week's time.
The damming of the channel will pave way for the third-phase of construction of the huge hydroelectric dam, which will be 2,309 meters long and 185 meters high.
Following the canal damming, water will be discharged mainly from 22 diversion holes on the lower part of the main dam, each six meters wide by 8.5 meters high.
Navigation on the canal, 350 meters wide and 3.7 kilometers long, was suspended Thursday. A total of 60 million tons of cargo and 13.53 million passengers have traveled the man-made canal since it was put into navigation in 1997.
The first two phases of the Three Gorges Project were concentrated chiefly along the northern bank. The mainstream of the Yangtze, China's longest river, was first dammed in November 1997.
Construction of the Three Gorges Project, which began in 1993, is expected to be completed in 2009, when 26 power generating units with a combined capacity of 18.2 million kilowatts go into operation. The permanent locks will also be able to accommodate ships of more than 10,000 DWT (dead weight tonnage).
The first group of four power-generating units will begin operation next year.
(Xinhua News Agency November 2, 2002)
