How Many More Dams in the Amazon?

by Emil Morhardt

There are a great many hydroelectric dams already operating in Brazil, supplying 80% of Brazil’s electricity—most of them in the Amazon Basin. There could be many more. The existing dams produce 80 million kilowatts annually, and the proposed dams in the Amazon Basin could double that. A just-released study maps these dams, and its Brazilian authors both warn of the damage their construction and operation could do societally and environmentally, and optimistically hope for “ An integrated ecological and environmental management with a holistic and systemic approach considering the entire spectrum of solutions, such as technology, socio-environmental conditions, and economy…” to avoid that damage. For sure, this ought to be a goal, and they note that just such studies are taking place on the Tocantins River where a 200 km stretch is proposed to remain free of dams. They note other mitigations taking place in other hydroelectric systems under development, including feasibility studies in the Tapajós River which suggest keeping reservoirs small with low retention times, and in the Araguaia River in which a proposed reservoir of almost 1,300 square kilometers was reduced to a much smaller artificial lake of 230 square kilometers with a retention time of 4 days.

All of this good, and I hope that the authors, all affiliated with academic institutes studying just these issues, will continue their studies and provide a much richer source of information about the current state of hydropower development in Amazonia. Without the kind of planning and implementation they discuss, it is likely that such development will result in massive environmental and socio-economic impacts in an undeveloped area that has the greatest existing biological complexity and sensitivity (and hydropower potential) in the world, and some of the last remaining undisturbed native human populations. The Brazilian authors are in a good position to provide this information. I hope they will be more comprehensive in future publications.

Tundisi, J., Goldemberg, J., Matsumura-Tundisi, T., Saraiva, A., 2014. How many more dams in the Amazon? Energy Policy DOI: 10.1016/j.enpol.2014.07.013. Abstract at:


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