After rushing out of Nanjin Pass, the Yangtze River slows down and widens from 300
meters to about 2,000 meters. Three kilometers east, in the suburbs of Yichang City, a
huge dam lies across the river. This is the Gezhouba Dam, a major part of the
multi-purpose water control project to bend the Yangtze to human purposes.
The main channel here was closed off on January 4, 1981,and navigation and power
generation began in June the same year, marking the completion of the first phase of the
key project. Beyond Nanjin Pass, two islets-Gezhouba (from which the dam project gets its
name) and Xiba-divide the river into three waterways, the main, second and third channels.
The main channel is filled with water all year round while the other two are dry during
the low-water season. The possibility of diverting the water of one into the others so
that construction work can be carried out makes the site ideal for the water conservancy
scheme.
Overview
With the closure of the main channel, the Yangtze has changed its age-old course to
roll forward through the second channel. Building a dam across the main section of a river
which is wide, deep and has an enormous flow is something unheard-of before.
Now the 2,561-meter-long dam has created a reservoir upstream with a holding capacity
of 1.58 billion cubic meters. The project involved the removal of 55 million cubic meters
of earth and rock, the installation of 65,000 tons of metal structures, and the pouring of
10 million cubic meters of concrete. This last figure equaled the combined total for the
five other key water conservancy projects in the country - the Liujiaxia, the Sanmenxia,
the Danjiangkou, the Gongzui, and the Xin'anjiang -and is enough to build a 10-meter-wide
and 50-centimeter-thick road extending from Guangzhou to Beijing.
The designing and construction of the dam and the installation of the equipment were
all undertaken by Chinese personnel. As far as the amount of work and the technical
standard are concerned, this cross-river structure ranks first among China's hydropower
projects.
A major component of the future Three Gorges multipurpose water conservancy scheme,
Gezhouba project consists mainly of power stations, ship locks, spillways silt-scouring
sluices, silt-prevention dykes and auxiliary dams.
Waiting for gate to open and come out of the shiplock.
There are two Power stations at the dam site one in the main channel the other in the
second channel. They have sets of turbo-generators, with a total installed capacity of
2.715 million KW to generate about 14.1 billion KWH of electricity a year. The biggest in
China today, they supply power to the central China grid, greatly promoting industrial and
agricultural Production in Hubei, east Sichuan, north Hunan and southwest Henan.
There are three shiplocks at Gezhouba. Lock No. 1 in the main channel and Lock No. 2 in
the third channel each have a chamber 280 meters long and 34 meters wide, with a depth of
five meters, allowing the passage of 10,000-ton passenger or cargo ships. They both rank
among the world's largest before Three Gorges Dam. Lock No. 3 in the third channel is 120
meters long and 18 meters wide, with a depth of 3.5 meters. It can handle vessels below
3,000 tons and local boats.
Two silt-scouring sluices and two silt-prevention dykes have been built to facilitate
navigation. When the reservoir is filled with water, the water level at the dam can be
raised by 20 meters. In the dry season, the water can retreat 180 kilometers, to the west
end of Wu Gorge, while at flood time, the water can move back as far as Badong, a distance
of 100 kilometers. With the conclusion of the first phase of the project, the water level
along the Three Gorges has been elevated by 10 meters and many shoals have been submerged,
greatly improving navigation.
Fully loaded No. 2 shiplock
The simultaneous operation of the 27-bay spillway and the three silt-scouring sluices
can discharge a water volume of 110,000 cubic meters per second, the maximum figure of the
1870 flood. Moreover, a railway-highway bridge has been built atop the dam. The bridge
surface can be raised or lowered to allow large ships to pass, the Maximum lift being 18
meters.
Apart from economic benefit, the Gezhouba project is a boon to tourism. With its
overall completion, a number of gardens will appear along this section of the river
together with tree-shaded roads at the sites of the three channels. Chinese and foreign
travelers visiting the Three Gorges will be tempted to include Gezhouba project in their
itinerary. They will find this man-made wonder a feast to the eye and the imagination, a
monument to human ingenuity in taming China's longest river.