Congo River and Basin

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Congo River and basin

The Congo River (also known as the Zaire River) is the third longest river in the world, and the second longest in Africa (after the Nile River in northeastern Africa). Its river basin, one of the most humid in Africa, is also the largest on that continent, covering over 12% of the total land area.


The equatorial region of Africa has been inhabited since approximately the middle Stone Age. Late Stone Age cultures flourished in the southern savannas after about 10,000 B.C. and remained functional until the arrival of Bantu-speaking peoples during the first millennium B.C. In a series of migrations taking place from about 1,000 B.C. to the mid-first millennium A.D., many Bantu-speakers dispersed from an area west of the Ubangi-Congo River swamp across the forests and savannas of the region known as the modern-day Democratic Republic of the Congo.

In the precolonial era, this region (modern-day Democratic Republic of the Congo) was dominated by three kingdoms: Kongo (late 1300s), the Loango (at its height in the 1600s), and Tio. Portugese navigator Diogo Cam was the first European to sail up the mouth of the Congo in 1482. After meeting with the rulers of the Kingdom of Kongo, Cam negotiated intercontinental trade and commerce agreementsincluding the slave tradebetween Portugal and the region. And a long history of colonialism began.

Over the centuries, the Congo River has inspired both mystery and legend, from the explorations of Henry Morton Stanley and David Livingstone in the 1870s, to Joseph Conrad, whose novel, Heart of Darkness transformed the river into an eternal symbol of the "dark continent" of Africa.


The Congo River is approximately 2,720 mi long (4,375 km), and its drainage basin consists of about 1.3 million mi2 (3.6 million km2). The basin encompasses nearly the entire Democratic Republic of the Congo (capital: Kinshasa), Republic of Congo (capital: Brazzaville), Central African Republic, eastern Zambia, northern Angola, and parts of Cameroon and Tanzania. The river headwaters emerge at the junction of the Lualaba (the Congo's largest tributary) and Luvua rivers. The flow is generally to the northeast first, then west, and finally south to its outlet into the Atlantic Ocean at Banana, Republic of Congo.

The Congo basin comprises one of the most distinct land depressions between the Sahara desert to its north, and the Atlantic Ocean to its south and west. The river's tributaries flow down slopes varying from 900 to 1,500 ft (274 to about 457 m) into the central depression forming the basin. This depression extends for more than 1,200 mi (about 1931 km) from the north to the south, from the Congo Lake Chad watershed , to the plateaus of Angola. From the east to west of the depression is another 1,200 mi (about 1931 km)from the Nile-Congo watershed to the Atlantic Ocean. The width of the Congo River ranges from 3.5 mi (about 5.75 km) to 7 mi (about 11.3 km); and its banks contain natural levees formed by silt deposits. During floods, however, these levees overflow, widening the river.

With an average annual rainfall of 1,500 mm of rain (about 60 in), about three-quarters returns to the atmosphere by evapotranspiration ; the rest is discharged into the Atlantic. The river is divided into three main regions: the upper Congo, with numerous tributaries, lakes, waterfalls, and rapids; the middle Congo; and, the lower Congo. The middle Congo is characterized by its seven waterfalls, collectively referred to as Boyoma (formerly Stanley) Falls. It is below these falls that navigation on the river becomes possible. The river has approximately 10,000 mi (about 16,000 km) of waterways, creating one of the main transportation routes in Central Africa.

Economic and environmental impact

Due to its size and other key elements, the Congo River and its basin are crucial to the ecological balance of an entire continent. Although the Congo water discharge levels were unstable throughout the second half of the twentieth centurythe hydrologic balance of the river has provided some relief from the drought that has afflicted the river basin. This relief occurs even with dramatic fluctuations of rainfall throughout the various terrain through which the river passes.

Researchers have suggested that soil geology plays a key role in maintaining the river's discharge stability despite fluctuations in rainfall. The sandy soils of the Kouyou region, for example, have a stabilizing effect in their ability to store or disperse water.

In 1999, the World Commission on Water for the twenty-first century, based in Paris and supported by the World Bank and the United Nations, found that the Congo was one of the world's cleanest riversin part due to the lack of industrial development along its shores until that time. However, the situation is changing.

The rapidly increasing human population threatens to compromise the integrity of Congo basin ecosystems. Major threats to the large tropical rainforests and savannas, as well as to wildlife , come from the exploitation of natural resources . Uncontrolled hunting and fishing, deforestation (which causes sedimentation and erosion near logging operations) for timber sale or agricultural purposes, unplanned urban expansion (which increases the potential for an increase in untreated sewage and other sources of pollution that could harm nearby freshwater systems), and unrestrained extraction of oil and minerals are some of the major economic and environmental issues confronting the region. And these issues are expected to have a global impact as well.


According to the World Wildlife Fund , the Congo River and its basin, also known as the "Congo River and Flooded Forests ecoregion," is home to the most diverse and distinctive group of animals adapted to a large-river environment in all of tropical Africa.

The Congo river had no outlet to the ocean during the Pliocene Age (5.42.4 million years ago) but was instead a large lake. Eventually, the water broke through the rim of the lake, emerging as a river that passed over rocks through a series of rapids, then entered the Atlantic. Except for the beginning and end of its course, the river is uniformly elevated.

With more than 700 fish species , 500 of which are endemic to the river, the Congo basin ranks second only to the Amazon in its diversity of species. Nearly 80% of fish species found in the Congo basin exist nowhere else in the world. The various species live both in the river and its attendant habitatsswamps, nearby lakes, and headwater streams. They feed in a variety of ways: scouring the mud at the river's bottom; eating scales off of live fish; and eating smaller fish. Certain fish have even adapted to the river's muddy waters. For example, some have reduced eye size, or no eyes at all, yet easily maneuver through the swift current. The Congo's freshwater fish are a crucial protein source for Central Africa's population; yet the potential for over-fishing near the urban areas along its banks threatens the available supply.

There are also a wide variety of aquatic mammalssuch as unusual species of otters, shrews, and monkeysthat are indigenous to the river basin. Rainforests cover over 60% of the Democratic Republic of the Congo, and represents nearly 6% of the world's remaining forested area, and 50% of Africa's remaining forests. Many of the world's endangered species live near the river, including gorillas.

River trafficwar, power, and tourism

At the end of May 2001, the United Nations Security Council announced that the Congo River would finally reopen to commercial traffic after a more than two-year blockage due to the war in the Democratic Republic of the Congo. Because of the desperate state of roads throughout the regionor the complete lack of roadsindividuals, business, and other agencies have relied primarily on river transportation.

The river had been divided in two at the front line of warring factionsthe government forces and their foreign allies on one side, and the rebels backed by Uganda and Rwanda on the other. Massive starvation resulted from the blockage, halting supplies from the United Nations and other humanitarian aid agencies.

With the drought that was running rampant through the early years of the twenty-first century, and those droughts that were anticipated in some areas of southern Africa, distribution of water remains a major challenge. In the fall of 2000, the Southern African Development Community, a group of Congolese business people, began to look to the Congo River for a solution to these water problems.

These developers launched a plan to pump water from the Congo River, by building two long-distance pipelines (known as the Solomon pipelines)one across the mouth of the Congo River to Walvis Bay in Namibia, 621 mi (about 1,000 km) away; the other, running through civil war zones. They would supply water to the Middle East by way of Port Sudan, a distance of nearly 1,242 mi (about 2,000 km).

The company initiating the plan, Westrac, claimed that the project would create hundreds of jobs, provide for the building of hospitals along the route, and lay fiber-optic communications links as wellthereby boosting the economy of the region and enhancing the lives of the native population. Detractors of the plan countered that the plan would be cost-prohibitive and hazardous to the environment. According to the California-based International Rivers Network, it was "premature to investigate such a complex plan when simpler and cheaper solutions haven't been fully explored," as reported by Radio Netherlands.

With political issues far from resolved as of 2002, and the potential for widespread pollution if industry and the population exploits the resources of the river, future plans could remain unresolved for decades to come. Yet, Salomon Banamuherem, the Democratic Republic of the Congo's minister of tourism, hoped that the project would tap into another great natural resource of the country and its rivertourism. In its entire history, even in times of peace, the countryAfrica's third largest countryhas attracted no more than100,000 visitors per year.

Despite unresolved political and economic issues, protecting the biodiverse resources and ecosystem of the Congo River and basin is perhaps the most important and challenging task facing this region in the future.

[Jane E. Spear ]



Fish, Bruce and Becky-Durost Fish.Congo: Exploration, Reform, and a Brutal Legacy. Philadelphia: Chelsea House Pub., 2001.

Tayler, Jeffrey.Facing the Congo. St. Paul: Ruminator Books, 2000.

The Congo Basin: Human and Natural Resourcs. Amsterdam: Netherlands Institute for IUCN, 1998.


Congo-pages. Congo River Basin. June 3, 2002 [cited July 2, 2002]. <>

Eureka Alert. Congo River Basin: Geology and soil type influence impact. January 11, 2002 [cited July 1, 2002].<>

Johnson, David. Africana. "Congo River called one of the world's cleanest." December 3, 1999 [cited June 2002]. <>


World Wildlife Fund, 1250 24th St. N.W, P.O. Box 97180., Washington, DC USA 20090-7180 Fax: 202-293-9211, Toll Free: 1-800-CALL-WWF, ,