text-only page produced automatically by LIFT Text Transcoder Skip all navigation and go to page contentSkip top navigation and go to directorate navigationSkip top navigation and go to page navigation
National Science Foundation Home National Science Foundation - Engineering (ENG)
Engineering (ENG)
design element
ENG Home
About ENG
Funding Opportunities
Awards
News
Events
Discoveries
Publications
Advisory Committee
Career Opportunities
See Additional ENG Resources
View ENG Staff
ENG Organizations
Chemical, Bioengineering, Environmental, and Transport Systems (CBET)
Civil, Mechanical and Manufacturing Innovation (CMMI)
Electrical, Communications and Cyber Systems (ECCS)
Engineering Education and Centers (EEC)
Emerging Frontiers in Research and Innovation (EFRI)
Industrial Innovation and Partnerships (IIP)
Proposals and Awards
Proposal and Award Policies and Procedures Guide
  Introduction
Proposal Preparation and Submission
bullet Grant Proposal Guide
  bullet Grants.gov Application Guide
Award and Administration
bullet Award and Administration Guide
Award Conditions
Other Types of Proposals
Merit Review
NSF Outreach
Policy Office
Additional ENG Resources
NSF National Nanotechnology Initiative
Other Site Features
Special Reports
Research Overviews
Multimedia Gallery
Classroom Resources
NSF-Wide Investments

Email this pagePrint this page


Press Release 13-090
Small Dams on Chinese River Harm Environment More Than Expected

Large dams previously thought to pose greater threat

Photo of the Nu River flowing near the Yunnan-Tibet border.

The ecologically diverse and scenic Nu River flows near the Yunnan-Tibet border.
Credit and Larger Version

May 28, 2013

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.

Large dams have been considered more harmful than their smaller counterparts.

But researchers' surveys of habitat loss and damage at several dam sites on the Nu River and its tributaries in Yunnan Province revealed that the environmental effects of small dams are often greater--sometimes by several orders of magnitude--than of large dams.

"Small dams have hidden detrimental effects, particularly when effects accumulate" through multiple dam sites, said Kelly Kibler, a water resources engineer who led the study while at Oregon State University.

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

She and Desiree Tullos, also a water resources engineer at Oregon State, report their findings in a paper accepted for publication in Water Resources Research, a journal of the American Geophysical Union (AGU).

"These researchers have taken advantage of what is essentially a natural experiment that allowed them to compare the effects of hydroelectric dams of different sizes," said Tom Baerwald of the National Science Foundation's (NSF) Directorate for Social, Behavioral & Economic Sciences, which co-funded the research with other NSF directorates. "The results are applicable beyond this region."

To compare the effects of small and large dams, Kibler investigated 31 small dams built on tributaries to 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 affected, 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 publicly-available information from hydropower companies, development agencies, and academic literature.

After evaluating data from the field, hydrologic models, and Environmental Impact Assessment reports on the small dams, Kibler and Tullos concluded that effects of the small dams exceeded those of large dams on nine out of the 14 characteristics they studied.

One particularly detrimental effect of the small dams is that they often divert the flow of the river to hydropower stations, leaving several kilometers of river bed dewatered, Kibler said.

From its headwaters in the Tibetan Plateau, the Nu River flows through China, Myanmar (Burma) and Thailand.

"While the number of small hydropower dams in operation or planned for tributaries to the Nu River is unreported," the authors state in their paper, "our field surveys indicate that nearly one hundred small dams currently exist within Nujiang Prefecture alone."

Thirteen large hydropower dams are proposed for the mainstem of the Nu River in Tibet and Yunnan Province in China.

Environmental, social, and economic factors make the Nu River basin extremely sensitive to hydropower installations.

In addition to supporting several protected species, the region is home to a large proportion of ethnic minorities and valuable natural resources, the authors report.

While large hydropower projects are managed by the central government, and both large and small hydropower projects undergo environmental impact assessments, decisions about small hydropower projects are made at a provincial or other regional level and often receive less oversight, Kibler and Tullos state.

The lack of regulation paired with a dearth of communication between small dam projects in China allows for the effects to multiply and accumulate through several dam sites, the authors write.

To mitigate the detrimental effects of small dams, there's a need for comprehensive planning for low-impact energy development, said Kibler and Tullos.

"The lack of analyses of the cumulative effects of small hydropower," Kibler said, "is a significant research gap with important policy implications."

-NSF-

Media Contacts
Cheryl Dybas, NSF, (703) 292-7734, cdybas@nsf.gov
Peter Weiss, AGU, (202) 777-7507, pweiss@agu.org

The National Science Foundation (NSF) is an independent federal agency that supports fundamental research and education across all fields of science and engineering. In fiscal year (FY) 2014, its budget is $7.2 billion. NSF funds reach all 50 states through grants to nearly 2,000 colleges, universities and other institutions. Each year, NSF receives about 50,000 competitive requests for funding, and makes about 11,500 new funding awards. NSF also awards about $593 million in professional and service contracts yearly.

 Get News Updates by Email 

Useful NSF Web Sites:
NSF Home Page: http://www.nsf.gov
NSF News: http://www.nsf.gov/news/
For the News Media: http://www.nsf.gov/news/newsroom.jsp
Science and Engineering Statistics: http://www.nsf.gov/statistics/
Awards Searches: http://www.nsf.gov/awardsearch/

 

Collage of two photos showing a river flowing before a dam and the old river bed dry after the dam.
A tributary of the Nu River is dry below a dam, its waters diverted by a hydropower project.
Credit and Larger Version

Small hydropower plant discharges water from tributary to main channel of the Nu River.
Small hydropower plant discharges water from tributary to main channel of the Nu River.
Credit and Larger Version

housed in the town of Liuku on the Salween (Nu) River banks in Yunnan.
Town of Liuku on the Salween (Nu) River in Yunnan.
Credit and Larger Version

Photo of boats and people on the Salween river forming the boundary between Burma and Thailand.
Salween, or Nu, River forming the boundary between Burma and Thailand.
Credit and Larger Version

Photo of the Salween Delta as seen from outer space.
The Salween Delta from space (south is to the upper left).
Credit and Larger Version



Email this pagePrint this page
Back to Top of page