Brazil planning to build 30 massive dams in Amazon by 2020
By Philip Fearnside / National Institute for Research in the Amazon
Brazil’s Belo Monte Dam on the Xingu River is now under construction despite its many controversies. The Brazilian government has launched an unprecedented drive to dam the Amazon’s tributaries, and Belo Monte is the spearhead for its efforts. Brazil’s 2011-2020 energy-expansion plan calls for building 48 additional large dams, of which 30 would be in the country’s Legal Amazon region. Building 30 dams in 10 years means an average rate of one dam every four months in Brazilian Amazonia through 2020. Of course, the clock doesn’t stop in 2020, and the total number of planned dams in Brazilian Amazonia exceeds 60.
The Belo Monte Dam itself has substantial impacts. It is unusual in not having its main powerhouse located at the foot of the dam, where it would allow the water emerging from the turbines to continue flowing in the river below the dam. Instead, most of the river’s flow will be detoured from the main reservoir through a series of canals interlinking five dammed tributary streams, leaving the “Big Bend” of the Xingu River below the dam with only a tiny fraction of its normal annual flow.
The official scenario for the Xingu River changed in July 2008 when Brazil’s National Council for Energy Policy (CNPE) declared that Belo Monte would be the only dam on the Xingu River. However, the council is free to reverse this decision at any time. Top electrical officials considered the CNPE decision a political move that is technically irrational. Brazil’s current president blocked creation of an extractive reserve upstream of Belo Monte on the grounds that it would hamper building “dams in addition to Belo Monte”. The fact that the Brazilian government and various companies are willing to invest large sums in Belo Monte may be an indication that they do not expect history to follow the official scenario of only one dam.
In addition to their impacts on tropical forests and indigenous peoples, these dams would make the Xingu a source of greenhouse-gas emissions, especially methane (CH4) which forms when dead plants decay on the bottom of a reservoir where the water contains no oxygen. The Babaquara Dam’s 23m vertical variation in water level, annually exposing and flooding a 3,580 square kilometer drawdown zone would make the complex a virtual ‘methane factory’. The reservoir’s flooding of soft vegetation growing in the drawdown zone converts carbon from CO2 removed from the atmosphere by photosynthesis into CH4, with a much higher impact on global warming.