The Madeira is the second largest river in the Amazon and the largest tributary of the Amazon River. Its basin covers a quarter of the Brazilian Amazon and has very rich biodiversity (see report: “The Amazon River’s largest tributary is under threat”, 2007, link below).
Two large dams , the Jirau and the Santo Antonio, are to be built on it in the Brazilian state of Rondonia, close to the Bolivian border. Work started in November 2008 on the Jirau dam (see Mongabay: “Brazil OKs $4 billion dam in the Amazon rainforest”, 13 Nov 08, link below).
This project has been strongly criticized for its potential damage to the environment and to the local populations. In addition to damage directly caused by the dams, opponents claim that new power lines and other developments will cause further destruction of the Amazon forest (see The Washington Post: “Doubt, Anger over Brazil dams”, 14 Oct 08, and WWF: “More studies needed for Amazon dams”, 9 Jun 09, links below).
The Madeira dams are also presented as the cornerstone of a series of projects that would see the construction of 140 dams in the Amazon basin, with 60 in the Brazilian Amazon alone (see International Rivers: “New online map plots 140 large dams planned for the Amazon”, 18 Aug 2010, link below).