Madeira River

The Madeira River is a massive waterway located in South America.

It serves as the largest tributary of the Amazon River. This means it is the most significant river that flows into the Amazon system. The Madeira is responsible for approximately 15% of the total water in the Amazon basin. Because it carries so much water, it is one of the largest rivers in the world by discharge. Its volume is about half the discharge of the Congo River. The river is vital for the ecology and economy of the entire region.

The river forms through the meeting of several great rivers. The main stem begins at the confluence of the Madre de Dios and Mamoré rivers. From this starting point, the Madeira flows northward. It acts as a natural border between the countries of Bolivia and Brazil. After this section, the river changes direction toward the northeast. It then travels through the Brazilian states of Rondônia and Amazonas. Finally, it reaches its junction with the Amazon River.

The Madeira's catchment area is incredibly large. This area collects water from many different locations. It receives drainage from the north-eastern slopes of the Andes mountains. It also collects water from the south-western slope of the Brazilian Mato Grosso. This catchment area is almost equal in size to the countries of France and Spain combined. Many large rivers flow into the Madeira to increase its volume. These include the Guaporé, the Baures, the Blanco, the Itonamas, the Mamoré, the Beni, and the Madre de Dios. The climate in the upper area varies from humid in the west to semi-arid in the south.

Historically, the river has been known by different names. An indigenous name for the river was Cuyari. A map from 1747 shows this pre-colonial name. The Portuguese called it Madeira, which means "Wood River." Many different indigenous groups have lived in this basin for centuries. These groups speak many different languages, such as Arawakan, Tupian, and Panoan. The river has also been a path for early technology.

Old steamships once traveled these waters to move people and goods.

Navigation on the Madeira depends heavily on the seasons. During the rainy season, the river can rise more than 15 meters. Large ocean vessels can travel up to the San Antonio falls near Porto Velho, Brazil. However, the dry months occur from June to November. During this time, only smaller craft can navigate the river. In the past, the river had famous rapids like the falls of Teotônio.

These rapids have a higher flow rate than the Boyoma Falls in Africa. Today, many of these rapids are submerged by the Santo Antônio Dam reservoir.

The river is a major highway for modern trade. It is one of the most active waterways in the Amazon basin. Large barges carry nearly four million tons of grains every year. These grains, mainly soy and corn, are loaded at facilities in Porto Velho. The barges travel downstream to ports like Itacoatiara or Santarem. From there, massive Panamax-type ships export the food to Europe and Asia. The river also moves fuel from the REMAN refinery in Manaus. This fuel supplies gasoline to the states of Acre, Rondônia, and Mato Grosso.

The ecology of the Madeira is remarkably diverse. The river is classified as "whitewater" because it is turbid. This means it has high levels of sediment, which makes the water look brown. This sediment comes from the high Andes mountains. The Madeira is one of the richest freshwater systems in the world. It contains more than 900 different species of fish. It is also the only home for the Bolivian river dolphin. This species is restricted to the upper Madeira River system. However, the construction of hydroelectric dams like the Jirau and Santo Antônio projects causes concern. Scientists worry that if fish ladders fail, migratory fish species could face extinction.