Madeira River

The Madeira River is one of South America's major rivers. It is part of the Amazon Basin and is the largest and most important tributary of the Amazon River. It accounts for approximately 15% of the water in the Amazon Basin. The Madeira's indigenous name was "Cuyari"; however, the Portuguese called it "Madeira," which means "Wood River."

The headwaters of the Madeira are located in the Bolivian Andes, approximately 3,300 km (2,050 mi) from its confluence with the Amazon and about 4,600 km (2,850 mi) from the Amazon's mouth. From its confluence with the Madre de Dios and Mamoré rivers and downstream to the Abuna River, the Madeira flows northward, forming the border between Bolivia and Brazil.

The Madeira traverses Brazil for approximately 1,425 km (885 mi) through the states of Rondônia and Amazonas before discharging into the Amazon near the town of Itacoatiara in the metropolitan region of Manaus.

The Madeira is formed by the confluence of the Madre de Dios/Beni and Mamoré rivers. Waters flowing into the Madeira include:

• the Madre de Dios River

• the Beni River

• the Mamoré River

• the Guaporé River

• the Machado River

• the San Miguel River

• the Blanco River

• the San Martin River

During the wet season, the Madeira River floods to about 15 m (50 ft) in height, inundating the forests on its flanks. Its climate differs as it flows from one area to another, from arid to more humid.

_{Map depicting the Amazon River drainage basin with the Madeira River highlighted}

Madeira Basin

Encompassing approximately 1,300,000 sq km (502,000 sq mi), the Madeira Basin covers about 19% of the Amazon Basin. Most of the Madeira Basin is within the lowland rainforest zone except in the south. Savanna predominates throughout the southern part of the basin. About 50% of the Madeira Basin is in Bolivia, 40% in Brazil and 10% in Peru. Brazil and Bolivia share a border along the Mamoré and Guaporé-Iténez rivers.

Wetlands cover a significant area within the Madeira Basin. The most extensive wetlands are the floodable savannas of the Llanos de Mojos region in the Department of Beni in Bolivia. Occupying approximately 180,000 sq km (69,500 sq mi), the Llanos de Moxos wetlands are the most extensive savanna wetlands in the Amazon Basin.

The Madeira Basin has high biodiversity, providing habitat to the spotted jaguar, giant otter, pink dolphin and many other endangered mammal species. In addition, an estimated 750 fish species migrate up to 4,500 km (1,700 mi) each year to spawn and feed in the nutrient-rich, muddy waters of the upper Madeira.

_{Map depicting the Madeira River watershed in Brazil, Bolivia, and Peru}