The Amazing Amazon River
The Amazon River is the second longest river in the world about 4,000 miles or 6,450 km long, second only to the Nile River. In terms of volume, the Amazon is the largest river in the world, it contains one fifth of the earth’s fresh water. Its width varies according to the rain season; at its widest point it can be 6.8 miles or 11km during the dry season and 24.8 miles or 40km during the rainy season. Where the river meets the Atlantic Ocean its width reaches 150 miles or 240 km. The river is so wide that in some parts it is impossible to see from one bank to the opposite; people sometimes refer to the Amazon River as the “river sea”. Learn more about Amazon River facts.
Amazon River and its tributaries. Click on map to enlarge.
The Amazon River flows east from the Peruvian Andes across Brazil and empties into the Atlantic Ocean. In 2000, a National Geographic Society expedition found that its most distant source is the melting snow cap of a mountain called Nevado Mismi in the Peruvian Andes. The stream of melting snow forms the Apurimac River which later joins the Ucayali River in east central Peru. The Ucayali River meets the Marañon River near the city of Iquitos, Peru forming the mighty Amazon River.
Melting glaciers in the Andes is the source of the Amazon River
The Amazon River is more than just one river, hundreds of small streams join larger ones until they reach the Amazon itself. This area is called the Amazon basin and covers more than 50% of the South American continent including most of Brazil and part of Peru, Colombia, Venezuela and Bolivia covering a total area of 2.5 million square miles or 6.5 million square km.
The Amazon has the largest number of tributaries more than any other river in the world. As many as 15,000 tributaries flow into the Amazon River and along its course the river system drains from parts of Bolivia, Brazil, Colombia, Ecuador, French Guyana, Guyana, Peru, Suriname and Venezuela.
The main tributaries of the Amazon River are:
- Marañon – 1600 km / 994 miles
- Putumayo – 1600 km / 994 miles
- Xingu – 1979 km / 1230 miles
- Japurá – 2414 km / 1500 miles
- Tapajós – 2010 km / 1249 miles
- Negro – 2400 km / 1491 miles
- Madeira – 3241 km / 2014 miles
- Trombetas – 756 km / 470 miles
- Purus – 3211 km / 1995 miles
- Napo – 1120 km / 696 miles
- Tocantins – 2699 km / 1677 miles
- Javari – 966 km / 600 miles
- Juruá – 1448 km / 900 miles
After flowing 4000 miles / 6450 km the Amazon empties into the Atlantic Ocean. As it approaches the Atlantic the current slows down and the water becomes muddy. The change in the color of the water is due to sediment, fragments of rocks from the Andes, left on the banks of the river forming a puzzle of islands and a number of channels that pour into the ocean. The largest island is the Island of Marajó which is about the size of Denmark. These islands continuously change shape as the sediment builds up and during the raining season water erodes it away.
The Amazon basin is one of the wettest regions in the world. It rains all year round but there are times when the rain is heavier particularly between mid-December to mid-May. During this wet season the water level can increase by up to 50 feet (15 meters) and many places flood creating pools of water where marine life strives.
The river has eroded the land flat and removed its nutrients leaving behind a soil composed mostly of inert acidic clay not suitable for agriculture.
Amazon River’s Economic Impact
People have lived in the Amazon River basin for thousands of years relying on it for fresh water, food and transportation.
The building of river ports along the Amazon River and its tributaries have been an important source of development. The Amazon River is the only method of transportation for local residents and companies doing business in the area. Many natural resources such as trees, agricultural crops and minerals make their way out navigating the rivers and into the cities.
Deforestation, the price of prosperity
Dams have been built along the Amazon River and its tributaries to produce hydroelectricity. Economic development and human activities are threatening the river. Pollution and deforestation from trade, mining, logging and agriculture are affecting the area’s ecology and possibly contributing to climate change.
Gold mining is an important industry in the Amazon rainforest. There are two ways to mine the gold. One is to dig and sift for gold dust and another is to pan for gold in the water of the rivers. The most popular technique and certainly not the most effective but available to anyone is the second one, this process require time and experience. Using this technique the men stand in the water with a small pan to test the sand for the amount of gold that it contains. If it the sand has enough gold then they will use a larger and flatter pan where they will swirl the sand and water. The lighter particles of sand will float and the heavier gold will stay at the bottom. Once the gold is mostly separated silver mercury is added making the gold flakes adhere. Later the mixture is heated and becomes solid. The amount of mercury released is polluting the river system and endangering its biodiversity.
More than three quarters of the Peruvian territory lies east of the Andes. The jungle or Selva has two parts, the high and the low Selva.
Mining and oil extraction are very controversial economic activities as they bring wealth and economic development but pollute the environment.
The Amazon river is home to many species of animals and many of them are in danger of extinction. Some of them are the pink dolphin, the Amazonian manatee and the giant river otter.
Between 1890 and 1920 the economy of the region suffer a boom due to the demand for its rubber.
Economic development is taking its toll among native Indians, many of them have fled deep inside the jungle, some have died of starvation and others have adapted to modern live.