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Geography: The Amazon River

February 06, 2010

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The Amazon is the world's largest river in terms of volume. Its total river flow is greater than the combined flow of the next eight largest rivers of the world and accounts for nearly one-fifth of the total river flow of the world and is also the world's largest drainage basin. A drainage basin is a part of land where water from melting snow or rain flows into a river, reservoir, lake, sea or ocean.

The Amazon River, due to its enormous size is also called as The River Sea, because during the rainy season, some parts of the river exceed a width of 190 kilometres. The area of the Amazon River is nearly 6,915,000 square kilometres and covers almost 40 per cent of South America. The Amazon drains into the Atlantic Ocean and during the rainy season, the amount of water Amazon drains is nearly 11,000,000 cubic feet per second.

It is also the world's second longest river with a total length of almost 6,400 kilometres.

Amazon's total depth during the rainy season reaches nearly 120 feet. The point of origin of the Amazon is Nevado Mismi, which is an 18,363 feet high mountain peak of volcanic origin, located in Peru's Andes mountain range. The Andes mountain range are the largest continental mountain range in the world situated at the western coast of the South Africa, nearly 7,000 kilometres long having a height of almost 13,000 feet.

The first explorer to navigate through the length of the Amazon River was a Spanish explorer, Francisco de Orellana. In 1542, when Francisco de Orellana arrived in this region, he was searching for gold. During his expedition, his crew was attacked by the natives, which included female warriors as well. And so, Francisco de Orellana gave this river the name of Amazon, as in Greek mythology 'Amazon' is referred to a nation of female warriors.

Apart from being a mighty river, the Amazon is part of the Amazon Rainforest, which is the world's richest and largest rainforest with nearly one-third of all species in the world living there. The forest occupies an area of almost 5.4 million square kilometres and has more than three thousand species of fishes.

There are nearly 1,100 tributaries of the Amazon and out of which 17 tributaries are more than 1,500 kilometres long. Some of the famous tributaries are Branco River, Casiquiare canal, Caqueta River Huallaga River, Madeira River, Tigre River and Tocantins River.

The Amazon is also significant as it drains one-fifth or 20 per cent of the fresh water which flows in the world's oceans. About 15 million years ago, the Amazon used to flow towards the west and drained into the Pacific Ocean. But after the continental shift, when the South American plate moved, the tectonic plates of this area rose and the flow of the river was blocked by the Andes Mountains. Over millions of years, the river gradually found another route and nearly 10 million years ago it started flowing towards east where its current drainage point lies in the Atlantic Ocean.