Hydroelectric dams may jeopardize the Amazon's future
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Hundreds of built and proposed hydroelectric dams may significantly harm life in and around the Amazon by trapping the flow of rich nutrients and modifying the climate from Central America to the Gulf of Mexico. These findings, published in Nature, emerge from a multidisciplinary, international collaboration of researchers from 10 universities, led by scientists at The University of Texas at Austin.
To meet energy needs, economic developers in South America have proposed 428 hydroelectric dams, with 140 currently built or under construction, in the Amazon basin—the largest and most complex network of river channels in the world, which sustains the highest biodiversity on Earth. The rivers and surrounding forests are the source of 20 percent of the planet's fresh water and valuable ingredients used in modern medicine.
While these hydroelectric dams have been justified for providing renewable energy and avoiding carbon emissions, little attention has been paid to the major disturbances dams present to the Amazon floodplains, rainforests, the northeast coast of South America and the regional climate, the researchers said.
Rivers in the Amazon basin move like a dance, exchanging sediments across continental distances to deliver nutrients to "a mosaic of wetlands," said Edgardo Latrubesse, UT Austin geography and the environment professor and lead author of the study. Sediment transported by rivers provides nutrients that sustain wildlife, contribute to the regional food supplies and modulate river dynamics that result in high habitat and biotic diversity for both aquatic and nonaquatic organisms.
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Read more at: https://phys.org/news/2017-06-hydroelectric-jeopardize-amazon-future.html#jCp
Full paper: https://www.nature.com/nature/journal/v546/n7658/full/nature22333.html
"More than a hundred hydropower dams have already been built in the Amazon basin and numerous proposals for further dam constructions are under consideration. The accumulated negative environmental effects of existing dams and proposed dams, if constructed, will trigger massive hydrophysical and biotic disturbances that will affect the Amazon basin’s floodplains, estuary and sediment plume. We introduce a Dam Environmental Vulnerability Index to quantify the current and potential impacts of dams in the basin. The scale of foreseeable environmental degradation indicates the need for collective action among nations and states to avoid cumulative, far-reaching impacts. We suggest institutional innovations to assess and avoid the likely impoverishment of Amazon rivers."
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