Madeira River
From Wikipedia, the free encyclopedia
The Madeira River is a major waterway in South America, approximately 3,380 km (2,100 miles) long.
Between Guajará-Mirim and the falls, the Madeira receives the drainage of the northeastern slopes of the Andes from Santa Cruz de la Sierra to Cuzco, the whole of the south-western slope of Brazilian Mato Grosso and the northern slope of the Chiquitos sierras. In total the catchment is almost equal in area to France and Spain combined. The waters flow into the Madeira by many great rivers, the principal of which, if we enumerate them from east to west, are the Guaporé or Itenez, the Baures and Blanco, the Itonama or San Miguel, the Mamoré, Beni, and Mayutata or Madre de Dios, all of which are reinforced by numerous secondary but powerful affluents.
All of the upper branches of the river Madeira find their way to the falls across the open, almost level Mojos and Beni plains, 90,000 km2 (35,000 square miles) of which are yearly flooded to an average depth of about 3 feet for a period of from three to four months.
From the falls, the Madeira flows northward forming the border between Bolivia and Brazil for approximately 100 km (60 miles). Below the confluence of the Rio Abunã, the Madeira meanders northeastward through the Rondônia and Amazonas states of north west Brazil to its junction with the Amazon. At its mouth is Ilha Tupinambaranas, an extensive marshy region formed by the Madeira’s distributaries.
It rises more than 15 m (50 feet) during the rainy season, and ocean vessels may ascend it to the Falls of San Antonio, near Pôrto Velho, Brazil, 1070 km (663 miles) above its mouth; but in the dry months, from June to November, it is only navigable for the same distance for craft drawing about 2 m (from 5 to 6 feet) of water. The Madeira-Mamoré Railroad runs in a 365 km {227 mile) loop around the unnavigable section to Guajará-Mirim on the Mamoré River.
A subspecies of Boto (Amazon River Dolphin) is known to inhabit the Madeira river system.
