The Amazon Basin and Its River System

The Amazon Basin covers approximately 7 million square kilometers, roughly 40 percent of the South American continent, spanning Brazil, Peru, Colombia, Bolivia, Ecuador, Venezuela, Guyana, Suriname, and French Guiana. At its center runs the Amazon River, which by discharge volume is the largest river on Earth, releasing an estimated 209,000 cubic meters of water per second into the Atlantic Ocean — more than the next seven largest rivers combined, according to figures compiled by Brazil's National Water Agency (ANA) and widely cited in hydrological literature. The river's length is measured at roughly 6,400 to 7,000 kilometers depending on the source point used, a long-running rivalry with the Nile for the title of longest river in the world; a 2007 study led by Brazilian scientists at INPE (National Institute for Space Research) argued for an Amazon source in the Peruvian Andes that would make it marginally longer than the Nile, though the claim remains disputed among geographers. The basin's main stem originates as the Marañón and Ucayali rivers in the Peruvian Andes, which converge near Nauta, Peru, to form the river that Peruvians and Brazilians alike call the Amazon (or, in its upper Brazilian reaches, the Solimões, before it merges with the Rio Negro near Manaus).