Potential impacts of planned Andean dams may outweigh benefits, say SNAPP-supported scientists

An international team of scientists investigating the effects of six planned or potential Andean dams on the Amazon river system has found that major negative ecological impacts can be expected both above the dams and throughout the lowland floodplains and the Amazon Delta.

The authors warn that, if not well planned, the construction of these dams and other infrastructure development in the Andes headwaters could have catastrophic effects across the entire Amazon River basin and threaten the food security of millions of people.

The study, entitled “The potential impact of new Andean dams on the Amazon fluvial ecosystem,” was published on August 23rd in PLOS ONE and conducted by the Amazon Waters Initiative, an offshoot of the former Amazon Waters working group supported by the Science for Nature and People Partnership (SNAPP), one of NCEAS’ collaborative initiatives.

According to the study’s models, the most dramatic effect of the six dams, which would be built in Peru and Bolivia, could be a reduction in the sediments flowing downstream by 894 million tons per year. This reduction represents 69 percent of all sediments flowing out the Andes and 64 percent of the entire Amazon sediment supply, impacting the entire central floodplain and delta region.

The Andes Mountains occupy only 11 percent of the Amazon basin, but supply 93 percent of the sediments and most of the nutrients carried by the Amazon river system. Sediment dynamics play an important role in shaping the Amazon’s fluvial landscape, moving and depositing sand, rocks, soil, and nutrients from the Andes to the rest of the Amazon basin.

“The expected reduction of sediment and nutrients beyond the dam sites would be catastrophic for the region’s wildlife as well as countless communities that rely on the river for their agricultural needs,” said lead author Bruce Forsberg, scientist for Instituto Nacional de Pesquisas da Amazonia.

Continue reading the full press release by our partner Wildlife Conservation Society.

Image credit: Ian Bell, Wildlife Conservation Society

 

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Posted on August 24, 2017