Over thereChina ponders: Are a few big hydropower projects better than many small ones?

Published 16 October 2009

China is moving aggressively to build dams along the upper reaches of the Yangtze River, in part to protect the Three Gorges Dam, but can such hydropower development be done better? “It’s not just dams versus no dams,” one expert says; “It’s about elegant dams”

The proposed Xiaonanhai Dam would stand athwart the mighty Yangtze River some thirty kilometers upstream of the industrial metropolis of Chongqing. The dam represents the single largest project in that municipality’s 11th five-year plan, costing roughly $3.5 billion. The growing city hopes to harvest 1.7 gigawatts of electricity from the river current of the Chang Jiang, as the Chinese call the third longest river on Earth.

David Biello writes in Scientific American that the dam is just one of nineteen proposed dams on the upper reaches of the Yangtze, upstream from the massive Three Gorges project near Yichang-and one of nearly 200 proposed dams on the Yangtze and its tributaries. China is building hydropower at a record pace that has resulted in more dams — 26,000 — than in any other country. In the last decade more than 60 percent of all hydropower projects worldwide were in China and Three Gorges alone will avoid the emission of an estimated 95 million metric tons of carbon dioxide a year-more than the combined output of Norway and Sweden.

Within 30 to 50 years, hydropower will be the main energy we should rely on,” Lai Hun Suen, a professor of sustainable development at Chongqing University and municipal government official, explained to me during a visit to the city in 2008. “It is a choice we made when we had no other choice.”

Biello writes that that choice has consequences: At least 1.2 million people moved to Chongqing, displaced by the rising waters behind Three Gorges. Decomposing submerged vegetation burps methane-a greenhouse gas which traps 25 times as much heat as CO2 over a century. A planned dam, Xiaonanhai, that would be built in the middle of the last remaining untouched habitat of the Yangtze sturgeon, giant salamander and 66 other fish species of concern, says Yan Xie, China Program director for the Wildlife Conservation Society. In fact, the proposed dam borders the “core protected area” of the Upper Yangtze Native and Rare Fish Reserve-an area set aside to mitigate some of the impacts of the construction of Three Gorges Dam.

There are 338 kinds of freshwater fish in the Yangtze River and 162 of them are endemic to the river-that is, found nowhere else,” says ecologist David Dudgeon of the University of Hong Kong. “It seems obvious that many or all of them could be impacted by a dam in the middle of