Major and irreversible damage may befall Brazil's Amazon river basin should an extensive dam-building project be set into motion there, a group of international scientists warned Wednesday, June 14.
The Amazon river basin currently has 140 hydroelectric dams already built or under construction. The extensive new dam project aims to increase that number to 428. However, researchers warn that such a program would devastate the complex river system and endanger the lives of unique species in the Amazon.
Building Dams For Renewable Energy
With more than 6 million square kilometers (2.4 million square miles) of cover, the Amazon river basin has become a key area for the construction of hydroelectric dams. This complex river system, considered as the largest on Earth, encompasses nine countries and preserves the highest concentration of biodiversity.
"The Amazon is the most important river basin on the planet," said Victor Baker, coauthor of the report. "It's a microcosm of our issues of today involving environment, energy and health of the planet."
Although building dams has been defended because it reportedly curbs carbon emissions and provides renewable energy, scientists say less consideration has been given to the cascade of effects that these dams present to the Amazon rainforests, floodplains, the regional climate, and South America's northeast coast.
This happens because most researchers only examine the environmental impact of a single dam, not the entire system. However, Baker said separating an individual dam assessment from the bigger system is "scientifically invalid."
"The river and its individual pieces cannot be separated out," he added.
Irreversible Damage In The Environment
That makes the issue of dam construction more urgent, researchers say.
In the new report, the team revealed a way to measure the impact of this dam construction project across a comprehensive range of criteria, known as the Dam Environmental Vulnerability Index (DEVI).
The DEVI, which ranges from one to 100, with 100 being the most vulnerable, considers the overall changes that occur in the river systems, such as erosion, changes in sediment deposition, runoff, possible land use changes, and the effects on the region's food supply and biodiversity.
Using the DEVI, Baker and his colleagues discovered that the largest Amazon tributary — the Madeira River watershed — will receive the greatest negative impact from the dam construction project. Baker and his team assigned that river an 80 in the DEVI.
Edgardo Latrubesse, lead author of the study, said the dams could prompt a change in the flow of sediments into the Atlantic Ocean and disrupt regional climate. Such damage may be irreversible.
"We are massively destroying our natural resources, and time urges us to find some rational alternatives for preservation and sustainable development," added Latrubesse.
In the end, researchers conclude that people living in countries covered by the Amazon river basin will ultimately decide whether hydroelectric power is worth the price of causing profound damage to this complex river system.
If the decision is made within the context of a comprehensive understanding of the system, the authors believe that the benefits of the rivers to humans and wildlife could be conserved.
Details of the report were published in the journal Nature.