Planned Dams for Andean Amazon May Negative Ecosystem Impact

The quest to capture more electricity from hydroelectric dams along the Amazon is increasing dramatically, spurring negative ecological impacts, reports a recent study led by Matt Finer of the Center for International Environmental Law.

This study states the Andean Amazon is becoming a major frontier for new hydroelectric dams. As such the potential impacts of these planned projects suggests that there may be serious ecological concerns, which must be taken into account.

The study analyzes the full portfolio of 150 planned dams across all six major river basins connecting the Andes to the Amazon, a geographic scope spanning Bolivia, Brazil, Colombia, Ecuador, and Peru. The full report is available  in the open access journal PloS ONE.

The report states the hydroelectric projects represent a potential 300 percent increase over the number of existing dams in the region. Over half would be large dams generating over 100 megawatts.

This fact is particularly alarming: Sixty percent of the dams would cause the first major break in river connectivity between protected Andean headwaters and the lowland Amazon, threatening the current free-flowing nature of many Andean-Amazon rivers.

“These results are quite troubling given the critical link between the Andes Mountains and the Amazonian floodplain,” Finer said. “There appears to be no strategic planning regarding possible consequences to the disruption of an ecological connection that has existed for millions of years.”

The Andes supply the vast majority of the sediment, nutrients, and organic matter to the Amazon floodplain, one of the most productive ecosystems for Earth. In addition, many important Amazonian fish species spawn only in Andean-fed rivers, including a number of long-distance migrants that must travel from the lowlands to the foothills.

The authors also found that more than 80 percent of proposed dams would contribute to forest loss due to new roads, transmission lines, or inundation. Including the potential new road and transmission line infrastructure needed for dams provides a much broader assessment of the full ecological impacts of proposed dams and their secondary effects.

In combining the river connectivity and infrastructure analysis, the authors produced an overall ecological impact score for each proposed dam. Nearly half were classified as high impact, while just 19 percent as low impact.

“We conclude that there is an urgent need for strategic basin scale evaluation of new dams and a plan to maintain Andes-Amazon connectivity,” said study co-author Dr. Clinton Jenkins of North Carolina State University. “We also call for a reconsideration of the notion that hydropower is a widespread low-impact energy source in the Neotropics.”

Source: Eurekalert 

Photo:  wallygrom

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