Small dams on Chinese river harm environment more than expected

Space Daily via SPX: A fresh look at the environmental impacts of dams on an ecologically diverse and partially protected river in China found that small dams can pose a greater threat to ecosystems and natural landscapes than large dams.

Although large dams are generally considered more harmful than their smaller counterparts, the research team's surveys of habitat loss and damage at several dam sites on the Nu River and its tributaries in Yunnan Province revealed that, watt- for-watt, the environmental harm from small dams was often greater -- sometimes by several orders of magnitude -- than from large dams.

Because of undesirable social, environmental, and political implications, the construction of large dams often stirs controversy. Current policies in China and many other nations encourage the growth of the small hydropower sector.

But, "small dams have hidden detrimental effects, particularly when effects accumulate" through multiple dam sites, said Kelly Kibler, a water resources engineer who led this study as part of her PhD research while at Oregon State University in Corvallis.

That is one of the main outcomes of this paper, to demonstrate that the perceived absence of negative effects from small hydropower is not always correct."...

Tiger Leaping Gorge in Yunnan, shot by Tdxiang, public domain