Geologists warn China's dam-building frenzy in seismically-active regions is putting millions at risk

July 7, 2012 – CHINA – As the last of the turbines at China’s Three Gorges Dam was connected to the grid on Wednesday, a dams debate rages over the fate of the Upper Yangtze River and its main western tributary, the Jinsha River. Known as the “River of Golden Sands,” the Jinsha is slated for a cascade of 25 dams designed to generate as much electricity as four Three Gorges Dams put together. Earlier studies by geologists have highlighted the seismic, safety, and water security risks of out-of-control dam building in this fragile region. Experts also warn against the risk of dam-building in China’s seismically active and flood-heavy southwest, where one dam break could cause a tsunami that creates a domino effect of collapsing dams downstream. This occurred in China in 1975, when a major flood and poor communications caused dam breaks at 62 sites in Henan Province. The catastrophe killed over 26,000 people – more casualties than any other dam failure in history. While such massive floods are rare (this was a once-in-1000-years flood), dam developers have yet to factor in the affects of climate change on extreme weather events such as droughts and floods, which are common in the southwest and have serious implications for dam operation. The valleys in this region, including those formed by the Lancang/Upper Mekong and Nu/Salween, also experience disastrous landslides during the rainy season due to the steepness of the terrain. These can be exacerbated by the clearing of vegetation for dam construction and by the filling and emptying of reservoirs. The fluctuating water levels of the Three Gorges reservoir, for instance, have destabilized hundreds of miles of slopes and triggered massive landslides. A recent warning sign is the deadly mudslide that occurred on June 28, 2012, at the Baihetan Hydropower Station on the lower Jinsha River (it is under construction by the China Three Gorges Project Corporation). The mudslide killed four people and left 36 more missing – all workers and their families at the dam construction zone. –IR

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