Amazon

Topic: World Physical Features and Natural Regions · NCERT: Beyond NCERT

Meaning

The Amazon is the river of South America that rises in the Peruvian Andes and flows east across northern Brazil to the Atlantic Ocean, which it reaches close to the Equator. It carries more water than any other river: about one-fifth of all river water reaching the oceans.

It matters because it is the world's largest river by volume, and it drains the world's largest tropical rainforest. Exams often test it against the Nile, which is the longest river, and the Congo, which carries the second-most water.

Explanation

Course: from the Andes to the Atlantic

• Source: it begins high in the Andes mountains of Peru, on the western side of South America.
• Direction: it flows east, right across the continent.
• Path: it crosses northern Brazil.
• Mouth (the place where a river ends in a sea): it enters the Atlantic Ocean close to the Equator.

Volume: why it carries so much water

• Discharge means the amount of water a river carries past a point each second. It is measured in cubic metres per second (m³/s).
• Amazon's discharge: more than 175,000 m³/s [2].
• Compared with the Congo: the Amazon carries over four times the Congo's flow. The Congo carries about 41,000 m³/s [2].
• Share of the world: about one-fifth of all river water that reaches the oceans comes from the Amazon.

Climate and river regime

• Regime means the pattern of a river's flow through the year.
• Cause: the basin lies in the Equatorial climate belt, so it rains in every month of the year.
• Process: this rain falls over a very large river basin (all the land whose rainwater drains into one river and its tributaries, which are smaller rivers that join it).
• Result: the Amazon flows high all year. It does not have one short flood season.

The basin and the rainforest

• The basin holds the world's largest tropical rainforest.
• The river and the forest depend on each other. Steady rain keeps the forest green and also keeps the river full.

Where it occurs

• Source: the Peruvian Andes in Peru.
• Main course: across northern Brazil, from west to east.
• Mouth: the Atlantic Ocean, close to the Equator.
• Basin: the world's largest tropical rainforest, in the Equatorial climate belt of South America.
• Other South American rivers, for location questions:
• Orinoco flows through Venezuela to the Atlantic and drains the llanos (tropical grasslands).
• Parana flows south to the Rio de la Plata estuary (Argentina–Uruguay). It has the Itaipu Dam on the Brazil–Paraguay border, and the Iguazu is one of its tributaries.

Don't confuse with

• Nile: the world's longest river (about 6,650 km). It flows north to the Mediterranean through dry land. The Amazon is the largest by volume.
• Congo River: second in discharge (about 41,000 m³/s) and the deepest river (about 230 m) [1][2]. It drains the second-largest tropical rainforest and crosses the Equator twice. The Amazon flows east and meets the Atlantic near the Equator.
• Orinoco: another South American river that flows to the Atlantic. It drains the llanos grasslands of Venezuela, not the rainforest.
• Mississippi–Missouri: known for its bird's-foot delta in the Gulf of Mexico. Do not mix it up with the Amazon in "river–mouth" match questions.

Prelims Hooks

• Largest river by volume: Amazon, at more than 175,000 m³/s. Longest river: Nile. Trap: the two are not the same river.
• Discharge order: Amazon first, Congo second. The Amazon carries over four times the Congo's flow [2].
• Source and mouth: Peruvian Andes → flows east across northern Brazil → Atlantic Ocean, near the Equator.
• Share of world flow: about one-fifth of all river water reaching the oceans.
• River and forest: Amazon drains the largest tropical rainforest. Congo drains the second-largest.
• Regime match: Equatorial rivers (Amazon, Congo) flow high all year. Monsoon rivers (Mekong, Blue Nile) have one big flood season. Arctic rivers (Ob, Yenisei, Lena) flood in spring.

Mains Points

• Climate decides the river regime:
• The Amazon's Equatorial climate gives rain all year, so its flow stays high in every season.
• Monsoon rivers such as the Mekong and Blue Nile rise in one season only. Arctic rivers such as the Ob, Yenisei and Lena flood in spring, when their southern headwaters thaw first.

• Comparing these regimes makes a strong GS-I answer on how climate controls drainage.

• Climate change and basin planning:

• Climate change can alter rainfall patterns, and with them the river regime.

• A river fed by all-year rain, like the Amazon, depends on the climate of its whole basin. So planning has to cover the entire basin, not just the river channel (GS-I physical geography; GS-III environment).

• River and rainforest as one system:

• The world's largest river by volume drains the world's largest tropical rainforest.
• What happens to the forest and to the rainfall over the basin will shape the river's flow. This makes the Amazon a key example in GS-III answers on protecting ecosystems.

Related concepts

• Nile
• Grand Ethiopian Renaissance Dam
• Congo River
• Victoria Falls
• Danube
• Tigris-Euphrates river system
• Mekong

Read more

• Great rivers and their basins