Physical and biological portrait of the Rio Madeira basin

Abstract

The Rio Madeira, although overshadowed by the voluminous Rio Amazonas, of which it is a major tributary, is still one of the largest rivers in the world (Figs. 1.1 and 1.2). Its headwaters are born on the snow covered peaks of the Bolivian Andes, just east of La Paz, and flow over 1,500 km before reaching the Rio Amazonas. In the family of tributaries contributing to the Rio Solimoes-Amazonas, it is unequalled in total drainage area, embracing about 1.3 million km2, or nearly one-fifth of the entire Amazon basin. The Rio Madeira’s total discharge is estimated to be about one trillion m3 per year, or more than one-fifth of the total annual volume of the Rio Anazonas; the massive Rio Negro, however, has a larger annual discharge which is estimated to be on the order of 1.4 trillion m3 per year (Hidrologia 1975–1979). The Rio Madeira’s annual volume is about twice that of the Mississippi’s and nearly equal to that of Africa’s largest river, the Zaire (Fig. 1.2).