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Small dams on Chinese river harm environment more than expected, study finds
http://www.agu.org/news/press/pr_archives/2013/2013-22.shtml[font face=Serif][font size=5]Small dams on Chinese river harm environment more than expected, study finds[/font]
28 May 2013
AGU Release No. 13-22
[font size=3]WASHINGTON—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.”
…
To compare the impacts of small and large dams, Kibler investigated 31 small dams built on tributaries of China’s Nu River and four large dams proposed for the main stem of the Nu River. She assessed the environmental effects of these dams in 14 categories, including the area and quality of habitat lost, the length of river channel affected, the amount of conservation land impacted, and the landslide risk. Because information regarding large dams is restricted under the Chinese State Secrets Act, Kibler modeled the potential effects of the four large dams using publically-available information from hydropower companies, development agencies, and academic literature.
After evaluating data from the field, hydrological models, and Environmental Impact Assessment reports about the small dams, Kibler and Tullos concluded that impacts of the small dams exceeded those of large dams on nine of the 14 characteristics they studied.
…[/font][/font]
http://dx.doi.org/10.1002/wrcr.2024328 May 2013
AGU Release No. 13-22
[font size=3]WASHINGTON—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.”
…
To compare the impacts of small and large dams, Kibler investigated 31 small dams built on tributaries of China’s Nu River and four large dams proposed for the main stem of the Nu River. She assessed the environmental effects of these dams in 14 categories, including the area and quality of habitat lost, the length of river channel affected, the amount of conservation land impacted, and the landslide risk. Because information regarding large dams is restricted under the Chinese State Secrets Act, Kibler modeled the potential effects of the four large dams using publically-available information from hydropower companies, development agencies, and academic literature.
After evaluating data from the field, hydrological models, and Environmental Impact Assessment reports about the small dams, Kibler and Tullos concluded that impacts of the small dams exceeded those of large dams on nine of the 14 characteristics they studied.
…[/font][/font]
