Indios of several tribes frim western Amazon have joined to criticize the Brazilian government for the construction of large hydroelectric dams in the Amazon, including dams on the Madeira river. The tribes organsed a gathering "of the Four Rivers", to protest against dams on the Madeira, Tapajos, Teles Pires and Xingu rivers: "We condemn the privatization of our natural resources, which brings insecurity and damages whole peoples, cultures and knowledge which have been around for thousands of years, as well as our forests, our rivers and our socio-biodiversity", and demanded the complete and immediate suspension of the construction of large dams on their rivers.

Following discussions with river-dwellers, non-governmental organizations and representatives of the Attorney General's office about the disastrous impacts the dams are bringing, the Indios participated in a protest march "in defense of life and against the construction of hydroelectric dams in the Amazon" and expressed their anger at the government's authoritarianism" in its push to build the dams.

The construction of the Santo Antonio and Jirau dams on the Madeira river in the western Brazilian Amazon is bringing large-scale immigration to the area, deforestation, the death of fish, dengue epidemics, and increased rates of prostitution and violence. The indigenous communities who are affected have not been adequately consulted and have not given their consent for the project to go ahead.

At least five groups of uncontacted Indians live in the area and their lives are at risk as land is being deforested and outsiders are bringing diseases to which they have little resistance.
European companies such as France's GDF Suez and banks such as Banco Santander are involved in the Madeira river project.

Survival International published a report highlighting the hugely negative impacts of hydroelectric dams on indigenous peoples worldwide.