A group of Peruvian scientists and environmentalists is urging caution and transparency as authorities weigh a Peru-Brazil “energy-integration” plan that is expected to call for construction of five to 15 hydroelectric dams in Peru’s portion of the Amazon Basin.

The first project on the list, a US$4 billion, 2,200-megawatt dam at the confluence of the Inambari and Araza rivers in southeastern Peru, would have about twice the capacity of Peru’s largest existing dam. It already has stirred passions on both sides, with some government officials touting the revenues the project could generate, while small farmers are fighting the project because it would flood their communities.

The project would be built by Egasur, a Brazilian consortium consisting of the Brazilian construction company OAS and the Brazilian state-run electricity companies Eletrobrás and Furnas. A dam on the Inambari River would not only take advantage of the greater generating capacity and smaller required footprint of a sloping site on the eastern flank of the Andes, but also would permit the regulation of water flows downstream to dams being built on the Madeira River in Brazil.