Congo River


The Congo River, formerly also known as the Zaire River, is the second-longest river in Africa, shorter only than the Nile, as well as the third largest river in the world by discharge volume, following the Amazon and Ganges–Brahmaputra rivers. It is the world's deepest recorded river, with measured depths of around. The Congo–Lualaba–Luvua–Luapula–Chambeshi River system has an overall length of, which makes it the world's ninth-longest river. The Chambeshi is a tributary of the Lualaba River, and Lualaba is the name of the Congo River upstream of Boyoma Falls, extending for.
Measured along with the Lualaba, the main tributary, the Congo River has a total length of. It is the only major river to cross the equator twice. The Congo Basin has a total area of about, or 13% of the entire African landmass.

Name

The name Congo/Kongo originates from the Kingdom of Kongo once located on the southern bank of the river. The kingdom in turn was named after the indigenous Bantu Kongo people, known in the 17th century as "Esikongo". South of the Kingdom of Kongo proper lay the similarly named Kakongo kingdom, mentioned in 1535. Abraham Ortelius labelled "Manicongo" as the city at the mouth of the river in his world map of 1564. The tribal names in Kongo possibly derive from a word for a public gathering or tribal assembly. The modern name of the Kongo people or Bakongo was introduced in the early 20th century.
The name Zaire is from a Portuguese adaptation of a Kikongo word, nzere, a truncation of nzadi o nzere. The river was known as Zaire during the 16th and 17th centuries; Congo seems to have replaced Zaire gradually in English usage during the 18th century, and Congo is the preferred English name in 19th-century literature, although references to Zahir or Zaire as the name used by the inhabitants remained common. The Democratic Republic of the Congo and the Republic of the Congo are named after it, as was the previous Republic of the Congo which had gained independence in 1960 from the Belgian Congo. The Republic of Zaire during 1971–1997 was also named after the river's name in French and Portuguese.

Basin and course

The Congo's drainage basin covers, an area nearly equal to that of the European Union. The Congo's discharge at its mouth ranges from, with an average of. The river transports annually 86 million tonnes of suspended sediment to the Atlantic Ocean and an additional 6% of bedload.
The river and its tributaries flow through the Congo rainforest, the second largest rainforest area in the world, after the Amazon rainforest in South America. The third-largest river in the world by discharge volume, following the Amazon and Ganges–Brahmaputra–Meghna rivers; the second-largest drainage basin of any river, behind the Amazon; and is one of the deepest rivers in the world, at depths greater than. Because its drainage basin includes areas both north and south of the Equator, its flow is stable, as there is always at least one part of the river experiencing a rainy season.
The sources of the Congo are in the highlands and mountains of the East African Rift, as well as Lake Tanganyika and Lake Mweru, which feed the Lualaba River, which then becomes the Congo below Boyoma Falls. The Chambeshi River in Zambia is generally taken as the source of the Congo in line with the accepted practice worldwide of using the longest tributary, as with the Nile River.
The Congo flows generally toward the northwest from Kisangani just below the Boyoma Falls, then gradually bends southwestward, passing by Mbandaka, joining with the Ubangi River and running into the Pool Malebo. Kinshasa and Brazzaville are on opposite sides of the river at the Pool, where the river narrows and falls through a number of cataracts in deep canyons, running by Matadi and Boma, and into the sea at Muanda.
Lower Congo constitutes the "lower" parts of the great river; that is the section of the river from the river mouth at the Atlantic coast to the twin capitals of Brazzaville and Kinshasa. In this section of the river, there are two significant tributaries, both on the left or south side. The Kwilu River originates in the hills near the Angolan border and enters the Congo some 100 km upstream from Matadi. The other is the Inkisi River, that flows in a northerly direction from the Uíge Province in Angola to the confluence with the Congo at Zongo some downstream from the twin capitals. Because of the vast number of rapids, in particular the Livingstone Falls, this section of the river is not operated continuously by riverboats.

Drainage basin

The Congo basin covers ten countries and accounts for about 13% of Africa. The highest point in the Congo basin is in the Ruwenzori Mountains, at an altitude of around above sea level.
Distribution of the Congo basin area between countries:

Discharge

[Kinshasa] and [Brazzaville]

Width and depth

Tributaries

Lower Congo Downstream of Kinshasa, from the river mouth at Banana, there are a few major tributaries.
Middle Congo
Upper Congo
  • Lilu
  • Ruiki
  • Lilo
  • Lowa
  • * Oso
  • Ulindi
  • * Lugulu
  • Kasuku
  • Ambe
  • Elila
  • Loho
  • Lubutu
  • Kunda
  • Luama
  • Luika
  • Lukuga
  • * Rusizi
  • * Malagarasi
  • ** Ugalla
  • ** Gombe
  • *** Moyowosi
  • Luvidjo
  • Luvua
  • * Kalungwishi
  • * Luapula
  • ** Chambeshi
  • Kalumengongo
  • Lovoi
  • Lufira
  • Lubudi
  • Lufupa

    Economic importance

Although the Livingstone Falls prevent access from the sea, nearly the entire Congo above them is readily navigable in sections, especially between Kinshasa and Kisangani. Large river steamers worked the river until quite recently. The Congo River still is a lifeline in a land with few roads or railways. Railways now bypass the three major falls, and much of the trade of Central Africa passes along the river, including copper, palm oil, sugar, coffee, and cotton.

Hydroelectric power

The Congo River is the most powerful river in Africa. During the rainy season over of water per second flows into the Atlantic Ocean. Opportunities for the Congo River and its tributaries to generate hydropower are therefore enormous. Scientists have calculated that the entire Congo Basin accounts for 13 percent of global hydropower potential. This would provide sufficient power for all of Sub-Saharan Africa's electricity needs.
Currently, there are about 40 hydropower plants in the Congo Basin. The largest are the Inga dams, about southwest of Kinshasa. The project was launched in the early 1970s, when the first dam was completed. The plan called for the construction of five dams that would have had a total generating capacity of 34,500 megawatts. To date only the Inga I and Inga II dams have been built, generating 1,776 MW.
In February 2005, South Africa's state-owned power company, Eskom, announced a proposal to expand generation through improvements and the construction of a new hydroelectric dam. The project would bring the maximum output of the facility to 40,000 megawatts. It is feared that these new hydroelectric dams could lead to the extinction of many of the fish species that are native to the river.

Natural history

The current course of the Congo River formed between 1.5 and 2 million years BP, during the Pleistocene. It is likely that during this period many upper tributaries of the Congo were captured from adjacent river basins, including the Uele and upper Ubangi from the Chari system and the Chambeshi River alongside a number of upper Kasai River tributaries from the Zambezi system.
The Congo's formation may have led to the allopatric speciation of the bonobo and the common chimpanzee from their most recent common ancestor. The bonobo is endemic to the humid forests in the region, as are other iconic species like the Allen's swamp monkey, dryas monkey, aquatic genet, okapi, and Congo peafowl.
In terms of aquatic life, the Congo River Basin has a very high species richness and among the highest known densities of endemics., almost 800 fish species have been recorded from the Congo River Basin, and large sections remain virtually unstudied. For example, the section in Salonga National Park, which is about the size of Belgium, had still not been sampled at all in 2006. New fish species are scientifically described with some regularity from the Congo River Basin, and many undescribed species are known.
The Congo has by far the highest diversity of any African river system; in comparison, the next richest are the Niger, Volta and Nile with about 240, 140 and 130 fish species, respectively. Because of the great ecological differences between the regions in the Congo basin—including habitats such as river rapids, deep rivers, swamps, and lakes—it is often divided into multiple ecoregions. Among these ecoregions, the Livingstone Falls cataracts has more than 300 fish species, including approximately 80 endemics while the southwestern part has more than 200 fish species, of which about a quarter are endemic.
The dominant fish families—at least in parts of the river—are Cyprinidae, Mormyridae, Alestidae, Mochokidae, and Cichlidae. Among the natives in the river is the huge, highly carnivorous giant tigerfish. Three of the more unusual endemics are the whitish and blind Lamprologus lethops, which is believed to live as deep as below the surface, Heterochromis multidens, which is more closely related to cichlids of the Americas than other African cichlids, and Caecobarbus geertsii, the only known cavefish in Central Africa. There are also numerous endemic frogs and snails. Several hydroelectric dams are planned on the river, and these may lead to the extinction of many of the endemics.
Several species of turtles and the slender-snouted, Nile and dwarf crocodile are native to the Congo River Basin. African manatees inhabit the lower parts of the river.