The potential negative effects of hydroelectric dams have strengthened opposition against the Brazilian government's plan to build two on the Madeira River, the largest tributary of the Amazon and which starts in the Bolivian Andes. “The Jirau dam would flood an area greater than the project plans, due to the sedimentation that could elevate the Madeira riverbed by six meters,” Glenn Switkes, of the International Rivers Network, told Tierramérica.

The Madeira carries half the sediment that ends up in the Amazon River, he said, corroborating the fears of the report released Oct. 3 by the Bolivian Forum of Environment and Development, about changes that could hurt fish populations and the water quality of Bolivian rivers.

The authorization for both dams lacks complementary studies about sedimentation, and public hearings have yet to be held, so the debate will be extended into next year, predicts Switkes