The Three Gorges Dam, key water control project of the Three Gorges on the Yangtze River was formally started on December 14 1994, and the total time of construction is expected to be 18 years.
The first phase of the project was completed in October 1997 when the great dam closed. The second phase was completed in 2003 while the water level upstream of the dam was raised to 135 meters above sea level. After third phase completed, and according to plan, the water level upstream of the dam was raised to 165 meters above sea level by 2006, and to 175 meters by 2009.
This is a feat in the history of China's development of her water resources, and adds a new wonder, beside the wonder by nature, to the Three Gorges on the Yangtze, the gold tourist route in China.
First, the great dam itself is a great modern work of man. Situated in the open valley in Xiling Gorge, it is connected to the 1,637-meter high Baiyanjian Peak on the southern bank, and to the 1,598-meter high Tanzi Peak on the northern bank, and the body of the dam is 1,983.15 meters long, not including the bridge approach and the span of the ship lock. And the top of the dam reaches 185 meters in height.There are ten locks on five stages in two directions, each lock is 34 meters wide, 280 meters long and the water is 5 meters deep. The total head drop is 113 meters, equal to 5 locks of the Gezhouba Dam. The flood discharge section of the dam is 483 meters wide and 94 meters high on three levels when it is relasing flood if needed. Such a waterfall is greater than any natural waterfall in China. Therefore, the great dam makes a splendid scene.
Second, the supporting projects of the great dam is also manificent. The Xiling Bridge that had been already completed, for instance, is 1,118.6 meters long and 18 meters wide, with a clear height of 30 meters and a single span of 900 meters. This single span is considered the longest one in China at present.
Third, when the water level upstream, of the dam reached 175 meters, an enormous body of water appears which is about 620 kilometers long and more than 1,100 meters wide on the average; and a great lake appears from the dam upstream, 7 to 8 kilometers long and 3 to 4 kilometers wide, covering a total area of 20 square kilometers. Naturally the great dam affects the existing scenery. But there is no doubt that the positive effects outweigh the negative ones.