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.
“People say ‘oh another dam, another river.’ It’s not. It’s the Amazon,” said Latrubesse, who is a faculty affiliate of the Teresa Lozano Long Institute of Latin American Studies. “We have to put the risks on the table and change the way people are looking at the problem. We are massively destroying our natural resources, and time urges us to find some rational alternatives for preservation and sustainable development.”
In the study, Latrubesse and collaborators introduced the Dam Environmental Vulnerability Index (DEVI), which was developed to determine the current and potential impacts of dams on rivers and their ecosystems in the Amazon basin. DEVI values quantify on a scale of 0 to 100 an area’s vulnerability to potential land use change, erosion, runoff pollution, trapped sediment and overall changes to river systems due to dams.
“To not have an integrated approach is to deny how nature works in the Amazon basin,” said Victor Baker, University of Arizona Regents’ Professor of Hydrology and Atmospheric Sciences and co-author of the study.” Our role is to show how nature works and that nature is integrated.”
Researchers found that many of the existing dams are located in areas of high sediment yield, such as the Andean Cordillera, which provides more than 90 percent of the detrital sediment to the entire system.
The Marañon and Ucayali rivers are the most vulnerable in this area (DEVI of 72 and 61, respectively), with 104 and 47 dams planned or constructed dams on each river, respectively. The researchers estimated 68 to 80 percent of the area upstream of the lowermost planned dam in these rivers will remain unprotected from dam influence, modifying the rivers’ dynamics, altering the creation of oxbow lakes and branches, decreasing floods and floodplain sediment storage, and putting thousands of species of birds, fish and trees at risk.
The Madeira River, which accounts for about half of the Amazon River system’s total sediment transported from Bolivia and Peru and is home to the most diverse fish population in the Amazon, has the highest DEVI values (greater than 80) and faces extreme risks of potential land use change, erosion, runoff pollution and trapped sediment. Here, two huge dams were recently constructed, the Santo Antônio and Jiaru dams, which led to a 20 percent decrease in the average sediment concentration in the Madeira despite unusually high flood dischargesNature in 2014 and 2015. Researchers expect a greater amount of the nutrient-rich sediment to soon be trapped by the additional trapping effect of 25 dams planned further upstream.
Other large rivers in the central highlands of Brazil are also being impacted, the researchers said. Investigation of the Tapajós River — where the main riverstem has not yet been directly disrupted, but 28 dams were recently constructed in its major tributaries — showed that the river and all its major tributaries will be impounded if developers move forward with 90 proposed dams and deforestation continues at its current rate.
“Think about putting dams in the Mississippi connecting artificial lakes from Memphis to New Orleans,” Latrubesse said. “It would be a scandal because it wouldn’t be sustainable. But this is what is proposed for the Tapajós River.”
Baker stressed that the Amazon is “the most important river basin on the planet. It’s a microcosm of our issues of today involving environment, energy and health of the planet.”
Amazon sediments nourish the largest preserved mangrove region of South America, along the coastline of northeast Brazil and the three Guianas, and past research has shown the sediments affect rainfall and storm patterns from the Amazon basin to Gulf of Mexico, Latrubesse said.
“The dimension of the impacts can be not only regional, but also on an interhemispheric scale,” Latrubesse said. “If all the planned dams in the basin are constructed, their cumulative effect will trigger a change in sediment flowing into the Atlantic Ocean that may hinder the regional climate.”
Edgardo M. Latrubesse, Eugenio Y. Arima, Thomas Dunne, Edward Park, Victor R. Baker, Fernando M. d’Horta, Charles Wight, Florian Wittmann, Jansen Zuanon, Paul A. Baker, Camila C. Ribas, Richard B. Norgaard, Naziano Filizola, Atif Ansar, Bent Flyvbjerg, Jose C. Stevaux. Damming the rivers of the Amazon basin. Nature, 2017; 546 (7658): 363 DOI: 10.1038/nature22333
University of Texas at Austin. “Hydroelectric dams may jeopardize the Amazon’s future.” ScienceDaily. ScienceDaily, 14 June 2017. <www.sciencedaily.com/releases/2017/06/170614133749.htm>.
Brazil is in the midst of a massive corruption scandal, which has implicated the current president, four former presidents, at least 50 members of Congress and thousands of politicians in ongoing bribery investigations. The scandal, coming just a year after the impeachment of former President Dilma Rousseff, furthers a crisis in which hardly any political leadership remains untouched by corruption allegations.
The resulting political environment has mixed implications for indigenous peoples. Positively, the investigation has highlighted corruption in government and in the agribusiness, extractive and infrastructure construction sectors where transparency is important for indigenous rights. But in the short term, attacks on indigenous rights appear to be accelerating. There is a real risk that amidst the political distractions, the National Congress will enact legislation which has serious long-term consequences for indigenous land rights.
This is something indigenous communities can ill-afford. Rural land conflicts are increasingly violent and have already claimed 37 lives since January. In April, ranchers attacked an indigenous settlement with machetes, hospitalizing 13 people. This continues a deadly trend: between 2003 and 2015, nearly 900 indigenous people were murdered in Brazil.
A key driver of this violence is land tenure insecurity for indigenous peoples, who face delays of years or decades in formalizing legal rights to their land, via a process known as demarcation. Stalled demarcations and evictions of indigenous persons can result in land conflict or violence. In the meantime, farmers may buy the land in good faith, not realizing it is indigenous land, creating subsequent conflicts.
Protecting indigenous land rights is crucial to addressing this violence. However, agribusiness interests opposed to greater recognition of indigenous land claims have gained political traction. Since 2016, the National Congress has proposed or enacted a range of measures designed to inhibit the demarcation process, while easing environmental and social protections around licensing for large economic projects. Demarcation has effectively ground to a halt. This is particularly disappointing because, historically, Brazil was a regional leader in terms of the indigenous land rights. Its Constitution was one of the earliest to recognize indigenous rights and remains one of the most progressive.
The last few months have seen sustained legal and political attacks on indigenous rights:
- In January, a regulatory change (Ministry of Justice Ministerial Order 80/2017) altered the process for demarcating indigenous lands to introduce a new technical group to advise on the process. Some indigenous activists have expressed concern that this introduces outsiders without expertise in indigenous affairs and undermines the role of the indigenous agency, known as FUNAI, in the process.
- A Decree issued in March (Decree 9010/2017) cut 87 out of the total 770 primary managerial positions at FUNAI. The cuts particularly affected staff dealing with the demarcation of indigenous land and environmental licensing for infrastructure projects.
- FUNAI’s budget has been cut by more than 40 percent this year, necessitating office closures and further slowing demarcations.
- Antonio Costa, the head of FUNAI, was dismissed in May, apparently due to his resistance to funding cuts to the indigenous agency and refusal to hire people without experience in indigenous affairs. Costa’s replacement, the fourth FUNAI president in the course of one year, is an army general who already faces opposition among indigenous activists.
Congress is also considering several concerning bills and has continued to move forward on restricting indigenous land rights during the political crisis:
- A proposed constitutional amendment (PEC 215/2000), would shift the demarcation process to Congress instead of an administrative process. Because Congress is currently controlled by a political bloc opposed to indigenous demarcations, this would likely halt the process.
- Two other proposed bills proposed (Draft Bills 1216/2015 and 1218/2015) would invalidate the current regulations governing demarcation, effectively stall any further demarcation, allow for broad revision to past demarcations, and allow for mining or other projects without consent where justified as in the public interest.
- A proposal to allow broad loosening of environmental licensing requirements poses additional risks to indigenous communities who are concerned about infrastructure, mining or other large-scale development activities on their lands.
- In May, a congressional panel recommended dismantling FUNAI and called for indictments against 67 persons (including FUNAI employees, anthropologists and 30 indigenous people) for supporting allegedly fraudulent indigenous land claims. The report also called for Brazil to reject certain international legal standards which protect the rights of indigenous persons.
As it stands, FUNAI is unable to carry out crucial responsibilities and indigenous peoples are unable to proceed with demarcation applications. The proposed legislation would result in long-term insecurity for indigenous persons, result in the revision of demarcations that have already been completed and undermine the right of indigenous persons to free, prior and informed consent of development projects on their land. Brazil needs to find practical ways to prevent and solve land conflicts, but this cannot occur without addressing the underlying problem of tenure insecurity for indigenous persons. It is accordingly crucial that the current political crisis does not become a convenient cover for a further erosion of indigenous land rights.