Amazon River
From Wikipedia, the free encyclopedia
The Amazon river (also named Rio Amazonas (Amazon river) in Portuguese and Spanish) is a river that flows in tropical forests of South America, mainly Brazil. It flows to the Atlantic Ocean. This river is the biggest by the amount of water it carries. It moves more water than the next eight rivers by amount put together. The Amazon, has the largest drainage basin in the world. It accounts for about one fifth of the world's total river flow. During the wet season parts of the Amazon exceed 120 miles (190 km) in width. Because of its size, it is sometimes called The River Sea.
Contents |
[change] Size and Path
It is one of the longest rivers in the world. There are different studies, that tried to measure its length. It is therefore difficult to say which of these rivers are really the Amazon. Also note that during the rainy season, the length of the river changes. Several studies from Brazil, Spain and Chile say it is the longest river in the world, longer than the Nile. The Nile has a length of 6.571 km. The Amazon may have a length of 6.937,08 kilometres, about 140 km longer than the Nile.[1][2][3] The Spanish daily newspaper El País gives its length at 6.850 kilometres.[4] This would make it about 40 kilometres longer than the Nile. In 2007, scientists from Peru and Brazil calculated a length of 6.800 km.[5]
A study done in 1969 says that the Amazon has a length of 6448 km. This was measured from a part of the River Apurimac. Until the 1970s, it was thought that the Marañón River was the source of the Amazon. In 2001, an expedition found that Nevado Mismi was in fact the source of the Amazon.[6] Another document of the Geographic society of Lima gives the length of the Amazon at over 7.000 km.[7]
The source of the Amazon lies in the Andes in Peru. The river that is called Amazon rises from the meeting of three source rivers, which are called Marañón, Huallaga and Ucayali. In 1909, Wilhelm Sievers said the source of the Amazon is that of the Marañón, Lake Lauricocha in central Peru. The Marañón is 1600 km long, and has the most water of the three rivers. The Ucayali is longer than the Marañón. Of its tributaries, the Apurímac River is the longest one. In 1975, the Apurímac was found to be the source of the Amazon. This was confirmed by an expedition in 2001.
[change] Flooding
The amount of water carried by the Amazon and its tributaries varies during the seasons. When there is a lot of water, the river will flood the surrounding forests. This creates a unique ecosystem known as Várzea. It also means that the size of the river can grow to be over hundred kilometres wide. For most of its course, the Amazon runs in an area where it is very flat. On average, the river only "drops" 3.5 centimeters over one kilometre. This means that rivers which are close together in the river system are often joined by natural "waterways".
[change] Estuary
The estuary of the Amazon is about 330 kilometres (205 mi) wide. The width of the mouth of the river is usually measured from Cabo do Norte to Punto Patijoca. Generally, the outlet of the Para River is included. It is 60 km (37 mi) wide, and forms the estuary of the Tocantins . The estuary also includes the island of Marajó, which lies in the mouth of the Amazon. This means that the Amazon is wider at its mouth than the entire length of the Thames in England.
Along the coastline, near Cabo do Norte, there are many islands partially covered with water. There are also sandbanks. The tides of the Atlantic generate a wave that reaches into the Amazon river. This wave goes along the coast for about 160 kilometres (99 mi). The phenomenon of this wave generated by the tides is called tidal bore. Locally it is known as pororoca. The pororoca occurs where the water is less than 7 m (23 ft) deep. It starts with a loud noise, and advances at a speed of 15–25 km/h (9–16 mph). The bore is the reason the Amazon does not have a delta. The ocean rapidly carries away the large amount of silt brought by the Amazon. This makes it impossible for a delta to grow past the shoreline. It also has a very large tide, that can reach 6 metres (20 ft). The place has become popular for river surfing.[8]
A phenomenon that is very similar occurs at the mouth of the Orinoco.
[change] Population
No bridges have been built over the Amazon.[9] This is not because the river would be too wide to bridge. For most of its length, engineers could build a bridge across the river easily. For most of its course, the river flows through tropical rainforest, there are very few roads and cities. Most of the time, the crossing can be done by a ferry, there is no need to build a bridge.
The river and its tributaries for the most part, flow through the Rainforest. Most cities lie on the banks of the river. The river is the main route of traffic in the region. The biggest city on the river is Manaus, which is also the capital of the Brazillian State of Amazonas. Many native peoples live in the Amazon, such as the Urarina[10] who live in Peru.
[change] Trade route
Big ocean ships can get up the river until Manaus's, which is almost 1500 kilometers from its mouth. Smaller ocean ships of 3,000 tons [11] and 7.9 m (26 ft) draft[12] can reach as far as Iquitos in Peru, 3,700 km (2,300 miles) from the sea. Smaller riverboats can reach 780 km (486 mi) higher as far as Actual Point. Beyond that, small boats frequently go up to the Pogo Ode Escherichia's, just above Actual Point.
[change] References
- ↑ Caderno Ciência, pág. 1, Folha de São Paulo, 3 July, 2008.
- ↑ Arce, Jean (1 May, 2007). Amazonas supera o Nilo como rio mais longo, dizem cientistas (Portuguese). Retrieved on 11 May 2008.
- ↑ Almeida, Maciel (16 May, 2007). Amazonas é o rio mais extenso (Portuguese). Retrieved on 5 November 2008.
- ↑ El río más largo del mundo (June 16, 2007).
- ↑ Amazon Longer Than Nile River, Scientists Say. National Geographic (2007).
- ↑ Explorers Pinpoint Source of the Amazon. National Geographic News (December 21, 2000).
- ↑ The Amazon River without Secrets (PDF) (2008).
- ↑ Pororoca: surfing the Amazon. Retrieved on 1 August 2008.
- ↑ Amazon (river). Microsoft Encarta Online Encyclopedia. Retrieved on 12 August 2007.
- ↑ http://www.upf.com/book.asp?id=DEANXS07
- ↑ Amazon - MSN Encarta
- ↑ Peru port information
[change] Other websites
