Carbon Credit Watch

Small dam construction to reduce greenhouse emissions is causing ecosystem disruption

(June 20, 2013) A new report says the global push to reduce greenhouse gases by building small dams, with the help of the Kyoto Protocol, is causing unanticipated and potentially significant losses to habitat and biodiversity.

“One of the things we found generally with small dams is that there was much less oversight and governance with the construction, operation and monitoring of small hydropower …. biophysical impacts of small hydropower may exceed those of large hydropower, particular with regard to habitat and hydrologic change.”

Desiree Tullos and Kelly Kibler, water resources engineers at Oregon State University, who led the five-year study of China’s Nu River on which these findings are based, say their research is relevant to not just China, but national energy policies in many nations or regions that seek to expand hydroelectric power generation.

In a press release published on June 18, Tullos notes:

“The Kyoto Protocol, under Clean Development Mechanism, is funding the construction of some of these small hydroelectric projects, with the goal of creating renewable energy that’s not based on fossil fuels. The energy may be renewable, but this research raises serious questions about whether or not the overall process is sustainable. There is damage to streams, fisheries, wildlife, threatened species and communities.

“The result can be profound and unrecognized impacts.”

Among the findings of the study as it relates to the Nu River region of China:

  • The cumulative amount of energy produced by small hydroelectric projects can be significant, but so can the ecological concerns they raise in this area known to be a “hotspot” of biological diversity.
  • Per megawatt of energy produced, small tributary dams in some cases can have negative environmental impacts that are many times greater than large, main stem dams.
  • Many dams in China are built as part of a state-mandated policy to “Send Western Energy East” toward the larger population and manufacturing centers.
  • Small dams can have significant impacts on habitat loss when a river’s entire flow is diverted into channels or pipes, leaving large sections of a river with no water at all.
  • Fish, wildlife, water quality and riparian zones are all affected by water diversion, and changes in nearby land use and habitat fragmentation can lead to further species loss.
  • The cumulative effect on habitat diversity can be 100 times larger for small dams than large dams.
  • Policies encouraging more construction of small dams are often developed at the national or international level, but construction and management of the projects happen at the local level.
  • As a result, mitigation actions and governance structures that would limit social and environmental impacts of small hydropower stations are not adequately implemented.

The press release in full is available here.

Related News

Small dams an even bigger dam problem, say researchers

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