The Yantze River Basin report, by Brenda Biersteker
Yangtze Kiang
Length: 6300 km
Runoff: 29.000 m3/s
Enviromental issues - The largest river of China
- During the monsoon-rains in spring the water level rise
Problems
For a century there has been spoken about placing a big dam in the three-gorges-area, a part of the Yangtze where the river floats through 3 very small gorges for more than 200 kilometres. When the dam rises, a lake of 175 metres deep, a kilometre wide and 200 kilometres long will appear. When heavy rain falls it is possible to use this lake to store the big flood of water caused by the monsoon. But when most of the rain falls downstream of the dam, the dam will have no influence on the possible flooding of the Yangtze-valley.
More than a million people had to move before the building of the dam started. They all had to start again on another place before the water of the Yangtze rises and forms a lake. The rising will flood thousands of cities and villages and a big part of all the fertile ground of China will be lost. The higher parts of the surrounding mountains are not suitable for building houses and growing crops, because the ground is to steep on many places.
Chang Jiang, or Yangtze Kiang in China
The Chang Jiang, known as the Yangtze Kiang is the largest river of China and the third largest of the world. Yangtze Kiang is the name given by the Chinese, meaning Long River and that’s what the Yangtze is with 6300 kilometre length.
The source of the Yangtze lays in Tibet, on the north side of the Tanglia-mountains, on the altitude of about 5000 metres. The source rivers are the Oelan, Moer, Moeroei, Oessoe and Agdam. The mouth of the Yangtze exists of a 36 kilometre wide estuary, and then it streams into the East-Chinese Sea at Shanghai.
On its way between source and mouth it passes seven different provinces and downstream, when the highland is traded for the Hoekwang-basin and the Yangtze reaches the wideness of 1000 metres, there are many big cities. Many sandbanks en islands in the middle of the wide stream, often surrounded by cliffs or handmade sand walls and dikes, mark the Yangtze.
For many years the catchments-area of the Yangtze was used to produce as lot food as possible and on a small piece of fertile ground for as many people as possible. That is why big parts of the surrounding slopes next to the Yangtze had to be made suitable for growing crops or building cities. Many trees were torn out and that’s why the ground cannot hold as much water as it used to be able to hold and when a lot of rain falls, the ground doesn’t take enough of it and a great part streams down the mountain to the river. Big dikes along the river keep the inhabitants of the Yangtze-area safe from the high water level, but the Yangtze cannot store the extra rain in area’s along the river as it used to do.
During the monsoon-rains in spring the water level can rise within a few hours for at least three and at most 40 metres, restricted by de wideness of the Yangtze at that point.
This can mean big trouble for the inhabitants of the Yangtze-valley, when the dikes cannot hold the big stream of water anymore. That is why the government of China wanted to find a solution to this problem of water rising in the spring.
The normal runoff of the Yangtze is about 29.000 m3/s, at high water level this can become more than 40.000 m3/s. In extreme cases a runoff of 83.000 m3/s was measured, this runoff caused serious flooding and a short of capacity to store this big flood of water.
For a century there has been spoken about placing a big dam in the three-gorges-area, a part of the Yangtze where the river floats through 3 very small gorges for more than 200 kilometres. When the dam rises, a lake of 175 metres deep, a kilometre wide and 200 kilometres long will appear. When heavy rain falls it is possible to use this lake to store the big flood of water caused by the monsoon. But when most of the rain falls downstream of the dam, the dam will have no influence on the possible flooding of the Yangtze-valley.
For the big shortage of energy in China the dam will be a good alternative because enough energy will be produced to supply all the new industry the dam will bring along and for the new cities high in the mountains.
Some fear that the three-gorges-project (Sanxia-project) will cause more sedimentation in the Yangtze on the point where the river flows into the lake. The Yangtze is a real sedimentation-river, it brings much sand and sediment what only sediments when the rate of flow is not too high. Now the most sedimentation is seen downstream, in the form of sandbanks and little islands in the river. When the lake comes to existence the flow rate of the stream will decrease even back to zero m/s, what causes fine sand and sediment to fall down instead of float along the stream. On the mouth of the lake a big sand bank will appear.
The shipping on the Yangtze can nowadays move until past the three-gorges-area, but when a dam rises, it won’t be possible anymore to follow this route. There are plans to create an elevator for ships, up to a certain volume, to lift them on the other side of the dam. But when there will be a sand bank on the mouth of the lake, the passage of ships will be limited. The Yangtze used to be called the Golden Waterway, but that is to be changed when the dam rises.
Also the animals in the Yangtze suffer under the building of the dam. A rare species of fresh-water dolphin lives in the Yangtze and eats a certain fish. But this fish swims upstream to breath. When the dam rises the fish will not longer be able to bring offspring and the end of the dolphin is near.
More than a million people had to move before the building of the dam started. They all had to start again on another place before the water of the Yangtze rises and forms a lake. The rising will flood thousands of cities and villages and a big part of all the fertile ground of China will be lost. The higher parts of the surrounding mountains are not suitable for building houses and growing crops, because the ground is to steep on many places.
When all benefits and disadvantages are considered it still is the question if the government of China does well by building the dam. The best reason, the safety of the people cannot be assured, when the monsoon strikes downstream from the dam. The economy of China will be better because the energy-yield and the new industries to be located. Positive economical function is often seen above any ecological disadvantage.
Catchments of the Yangtze River.
The following links contain useful information about the Yangtze Kiang and the Tree Gorges Dam:
http://www.ctgpc.com/HTML/Information/hottalks/inht0201-1.htm
http://www.nextcity.com/ProbeInternational/ThreeGorges/background.html
http://www.nextcity.com/ProbeInternational/ThreeGorges/3gphoto1.html
http://www.dse.nl/bewoners/svberlo/index.html
Welcome to China
Welcome to China II
Officiële site van het project
Drei-Schluchten Project, Duitse site
Three Gorges dam campaign
sediment problems at three gorges dam
meer info over de gevolgen voor de chinese cultuur
Three Gorges Dam on the Yangtze
Relocations for China Dam are found to lag
History of dams in China
Silence on Three Gorges Dam grows deeper
Resettlement disaster
Jiang Zemin\\\\\'s Speech
Ted case studies, Three Gorges Dam
http://www.ctgpc.com/HTML/Information/hottalks/inht0201-1.htm
http://www.hrichina.org/pr/english/980312.html
http://www.solidsoftware.com.au/yangtze/flood.html
http://www.solidsoftware.com.au/yangtze/Default.htm
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