Dams and Landslides

Chinese geology experts question South-North Water Diversion Scheme’s viability

Grainne Ryder, Stephen Thomas and Mu Lan
Three Gorges Probe
August 31, 2007

Officially it’s the answer to northern China’s water crisis but senior Chinese geologists and experts are not confident that the central government’s plans for diverting water from the upper Yangtze into the parched Yellow River valley is worth the extraordinary risk and cost.

At a forum organized by China’s Academy of Geological Sciences earlier this year, experts conducting geological surveys along the western route of the south-north diversion scheme, as it’s known, questioned its technical viability.

Independent researchers, Yang Yong and Peng Hua, presented three main concerns.

First, the amount of water to be pumped from three Yangtze tributaries – about 17 billion cubic metres per year – exceeds the available water supply, in a region where glaciers are shrinking and deserts are expanding.

Second, the proposed diversion route is within a seismically active area prone to mud-rock flows and landslides.

Third, twelve large hydro projects are planned or under construction upstream from the proposed diversion, which will create “fierce competition between the hydro projects and the water diversion project authority” that will result in wasted state funds.

Peng Hua, who spent years investigating the geological conditions for the Tibet-Yunnan Railway before starting to investigate the western route, concurred that the entire region is earthquake-prone. He said building six dams and seven tunnels could induce earthquakes, disturb the groundwater system, and cause landslides around the reservoirs. And while the dams could be designed to safely withstand earthquakes, the bigger engineering challenge is the long and deep tunnels that would be subject to rock slides and high stress due to seismic activity. He concluded, however, that these problems could be solved with “more sophisticated investigations and advanced engineering technology.”

Others were less optimistic. Professor Lu Yaoru of the Academy suggested that the ministry of water resources organize a multi-disciplinary team to study the western route more thoroughly before going ahead. “It’s crucial for us to deal with each stage separately: survey, design and construction.”

Professor Zhao Wenjin, of the Chinese Academy of Sciences raised four questions that need answered:
• How much water is available for water diversion?
• Would pumping that water out damage the area?
• How can sustainable development in the project area occur if water is diverted to other regions? and
• What about the seven locations chosen to build reservoirs, are they feasible? Silt could accumulate in the reservoirs much more quickly than anticipated and, as a result, will likely have a much shorter life than anticipated because less water can be stored in the reservoirs.

Professor Zhao added that it is “inappropriate to deal with such a big project from a purely engineering point of view. The actual situation is much more complicated than we thought because the area where the project is supposed to be built is unstable as a whole. What we should try to do is have a better understanding of the relationship between nature and mankind in the concerned region.”

Ha Chengyou, senior researcher at the China Academy of Geological Environmental Monitoring, added that it was still unclear how much water can be diverted from the area, and what the impact would be on the environment in the affected areas.

The original article, published in Mandarin, appeared in Science Times (Kexue Shibao) on August 3, 2007.

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