Three Gorges Probe

Leading scientists warn about impacts of Three Gorges dam

Kelly Haggart

December 20, 2002

 

Three prominent scientists who took part in the environmental impact assessment conducted by Chinese researchers 15 years ago for the Three Gorges project still stand by the conclusion of that study, which raised serious concerns about building the dam, a Chinese publication reports.

 

 

They also sound a warning about the threat the dam poses to China’s fish supply, and to rare plant species that may already have been lost forever as a result of the current effort to clear away vegetation from the bottom of the future reservoir.

Writing in News Weekly, a magazine published by China News Service (Zhongguo xinwen she), journalist Tang Jianguang reports that scientists such as Chen Guojie, who was in charge of the comprehensive environmental study and chief author of its final report, continue "to insist on the conclusion presented by researchers from the Chinese Academy of Sciences (CAS) in the mid 1980s: that purely from the standpoint of the environmental impacts, the costs of building the Three Gorges dam definitely outweigh the benefits. Prof. Chen [who is a senior researcher at the Chengdu Institute for Mountain Hazards and Environment] and many other scientists believe that it is difficult, with the current level of science and technology, to come up with precise answers and adequate solutions to the uncertainties and hidden problems that the project holds for the environment in the reservoir area."

"Many Chinese scientists agree that building the Three Gorges dam will accelerate environmental degradation in the reservoir area and in the middle and lower reaches of the Yangtze," Mr. Tang writes. ". . . The most severe impacts will centre on the following aspects: the population-carrying capacity in the reservoir area will become much smaller, soil erosion will become increasingly severe, and certain endangered species will face critical conditions. The negative impacts began with the formal start of the dam project and will last for 50 and even 100 years after the filling of the reservoir. In some cases the impacts will be hidden, unforeseen and long-term."

Mr. Tang quotes Chen Weilie, a senior scientist with the Institute for Plants, a Beijing-based branch of the CAS, as saying that four or five endangered plant species, which grow only in the Three Gorges area, cannot now be found. "’You see, everything has gone, and there is little vegetation left on the cliffs of both banks below 135 metres because of the cleanup campaign,’" he said sadly, pointing to the clean-cut cliffs and rocks along the Yangtze River."

Chen Weilie said that he and his colleagues probably will be able to save about 30 other rare plant species found in the reservoir area. They took steps to protect them by establishing, in 1996, the Three Gorges Rare Plant Resources Conservation Station in a remote mountainous part of Hubei province about 100 kilometres north of the Three Gorges area.

But perhaps the most alarming part of Mr. Tang’s article relates to the threat to fish production in the Yangtze River, which currently provides half of China’s freshwater fish supply.

"Compared with the rare plants, which could be protected in a new resettlement site, aquatic species face greater uncertainties," Mr. Tang writes. He quotes Cao Wenxuan, a CAS member and senior researcher at the Wuhan-based Institute for Aquatic Life, as warning that the dam could seriously jeopardize the Yangtze fishery by blocking fish migration routes and changing the conditions on the floodplain below the dam that fish require to spawn and grow.

"The ecosystem of the Yangtze River has evolved over millions of years. But the big dam will bring about violent and drastic changes to that ecosystem, and aquatic life will have a hard time adapting," Mr. Tang writes. "Changes in the river regime, such as water velocity and temperature, and sedimentation would significantly affect the fish habitat, especially breeding and feeding conditions. Undoubtedly, all these changes will come as major shocks to the fish living both in the upstream and downstream sections of the river. . . .

"The Three Gorges project will change the flow of water on the river, with floods controlled according to human will. But it is these same floods that provide a paradise for fish, which spawn in the floods–the bigger the better. The floods that are regarded as disasters in human terms are a necessary condition for fish production. Another problem is that a lower water temperature below the big dam is likely to shorten the fish maturation period.

"A combination of the above factors, plus other unforeseen changes in the aquatic environment, could seriously undermine the fishery in the river as a whole."

Categories: Three Gorges Probe

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