Three Gorges Probe
May 8, 1996
A world renowned expert in river sedimentation has written the United States Export-Import Bank warning that the “inherent risks” of sedimentation at the Three Gorges dam constitute a “strong reason to refrain from providing US support” for the project.
The Ex-Im Bank is currently considering granting hundreds of millions of dollars in export credits to US companies seeking to become involved in the controversial Chinese dam project.
In a paper titled “Sediment Problems at Three Gorges Dam,” Luna B. Leopold, Emeritus Professor of Geology at the University of California Berkeley, warns that “Projections of controlling sedimentation within the [Three Gorges] reservoir are subject to significant uncertainties.” “These uncertainties,” Leopold continues, “lead to the conclusion that “the financial benefits expected [from the project] may be in error and that investing in the project would be unwise.”
Leopold is also a member of the National Academy of Sciences, Fellow of the American Academy of Arts and Sciences, and recipient of the National Medal of Science.
According to Chinese authorities, the Three Gorges dam will store clear water and flush out sediment-filled water, thereby minimizing sedimentation problems in the massive reservoir. But the Yangtze River, which the Three Gorges is damming, is the world’s fourth most sediment-laden river. And, as Leopold warns, “the world’s experience with this type of operation is very meagre.” Only 17 reservoirs in the world operate in the manner proposed and the largest of them, Sanmenxia in China, is only a fifth of the size of the Three Gorges.
The experience of the Sanmenxia dam does not bode well for Three Gorges. The rate of sedimentation at Sanmenxia was grossly underestimated when it was built and the tons of sand that were deposited in the reservoir by the Yellow River’s waters crippled the dam after only two years of operation. As a result, the dam had to undergo radical and costly redesign. It will never function as planned, and is widely regarded outside China as an economic white elephant.
“The Three Gorges Dam is designed to operate under conditions practically untested in the world and never before tested in such a large structure,” says Leopold. Projections of reservoir sedimentation for the Three Gorges project “involve many assumptions of unverified reliability,” and any difference between the forecast and actual performance, writes Leopold, “has large financial, environmental and humanistic implications.”
The Ex-Im Bank has been slow to decide whether to provide support for US companies interested in contracts to build Three Gorges. Last September, the White House sent a letter to then Ex-Im president Kenneth Brody stating that the White House thought it “unwise for the US Government to align itself” with so controversial a project. Since then, Ex-Im’s ability to make decisions regarding loans to China has been dogged by worsening US-China relations and most recently by China’s alleged sale of nuclear materials to Pakistan.
The Three Gorges dam would be the world’s largest hydroelectric project. Two kilometres wide, with a reservoir stretching 600 kilometres upstream of the dam, the project will uproot 1.3 million people from their homes and endanger a number of rare aquatic species. Official Chinese estimates put the cost of the project at US$30 – US$50 billion, but unofficially the accepted price tag is in the neighbourhood of US$74 billion.
To read Professor Leopold’s submission to the Export-Import bank of the United States click here.
Categories: Beijing Water