scientists evaluate madeira river hydro energy projects

Improve the quality of the environmental, social and economic evaluation, as well as explore energy alternatives

Scientists concur after analyzing the proposed hydro-energy infrastructure in the Amazon

© Jorge Molina / IHH-UMSA

La Paz, May 20th, 2009 – It is essential to improve the environmental, social and economic evaluation regarding the hydro-energy projects underway and planned for the Madeira river watershed, and that these criteria serve as the basis for decision making in relation to sustainable energy development in the Amazon. These were among the main conclusions reached during the International Symposium "Environmental Impacts Assessment of Large Hydroelectric Dams in Tropical Regions: The case of the Madeira river ", held in La Paz, Bolivia, from May 19th to 20th, 2009.

Mr. Jorge Molina from the Institute of Hydraulics and Hydrology from the Main San Andrés University (IHH/UMSA), and responsible for leading the event together with the Institute for Research and Development (IRD) and WWF, the global conservation organization, showed that the Brazilian dams of Jirau and Santo Antonio would cause hydraulic and hydrological impacts in Bolivia, including an increased risk of floods.

IHH, IRD and WWF have been supporting research and dissemination of technical information related to the possible impacts that might occur in Bolivia as a result of the construction of dams on the Madeira river in Brazil, aiming to provide input for stakeholders to be able to influence decision makers, minimize negative impacts and promote the development of sustainable energy infrastructure in the Bolivian Amazon. The scientists’ main concerns revolve around the sensitivity of the northern Amazon in Bolivia in regards to the dams, and the need for improved evaluations.

It is estimated that 80% of fish in the Bolivian Amazon are migratory, and some of the species with an important value from a commercial and subsistence point of view could be affected. “Within the possible impacts are the gradual reduction in fishing, which could affect at least 16,000 Bolivian families whose livelihood depends on this activity”, indicated Paul Van Damme, from the FaunAgua Association.

Mr. Marc Pouilly, from IRD, also warned that “there is considerable data that is precise and which predicts that floods will occur as a consequence of the dams, which could affect the use of natural resources and increase diseases such as malaria, yellow and dengue fevers. It is very important to carry out further studies to estimate the extension of the area of the Bolivian Amazon that could be flooded, as well as the impacts in the dams’ nearby areas and down river”.

According to Mr. Jean Remy Davée Guimaraes, from the Federal University of Rio de Janeiro (UFRJ), other impacts that have been observed in dams that are constructed in tropical areas is the increase in mercury in fish (in the reservoir and mainly down river), deforestation in the area along the power lines, contamination with herbicides to maintain these power lines, retention of sediments and erosion on river banks.

Mr. Miguel Petrere from the Paulista State University (UNESP) in Brazil, indicated that, based on the experience with tropical dams, we know that these do not offer clean energy, “the diversity, population and size of fish considerably diminished after dams were constructed. The scientific community can help find alternative energy, as well as locations for the dams, so as to minimize the repercussions for humans and the environment”.

In terms of socioeconomic impacts, Mr. Manuel Antonio Valdés, from the Rondonia Federal University (UNIR), added that, in the case of Brazil, 65% of the population that was visited in the area of the Madeira river (close to 1,100 families) will very likely have the need to move, leaving behind their animals, crops, customs and ways of life in harmony with the river. Of these, only 30% have land property titles, which would make social compensation efforts difficult.

During the inauguration, the Director for IRD, Ms. Marie-Danièlle Demelas, highlighted the important role of the dams for human development, but also reminded the audience that in many cases these have generated unacceptable costs and which are many times unnecessary in both social and economic terms.


Scientists from Bolivia, Brazil, Ecuador, the United States and France participated in this Symposium as speakers. They have been developing research on the possible economic, social and environmental impacts that would result as a consequence of building the dams in the Amazon watershed, and in particular the Madeira river watershed.

The Madeira river is the Amazon’s main tributary and supplies the greatest quantity of water and sediments, allowing for its unique biodiversity and balance in the entire Amazon basin.

For further information:

Jorge Molina, IHH/UMSA:

Marc Pouilly, IRD:

Nardyn Pizarro, WWF:

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