African Regional Working Group

|The Lake Chad Basin |The Congo Basin |The Niger Basin | The Nile Basin | The Orange Basin | The Zambezi Basin |

Major Basins of the Group

There are six major river basins in Africa summarized as follows :

The Chad Basin
The Congo Basin
The Niger Basin
The Nile Basin
The Orange Basin
The Zambezi Basin

The Lake Chad is an important international shallow freshwater source that depends for 90-95% of its supply from the Chari Rivers system and its surface area varies from 2 000 km2 to 25 000 km2 depending on the annual amount of rainfall. The population within the basin from Cameroon, Chad, Central African Republic, Niger and Nigeria, is estimated at over 20 million people. The associated floodplains of the Lake Chad cover almost 100 000 km2 where water demand is increasing while drought and desertification are attenuating water flow in the three sub-basins that constitutes the Lake Chad basin. This system is the second largest wetland in Africa and hosts biodiversity of global significance while the floodplains support a wide range of economic activities - recession agriculture, pastoralism, forest regeneration, fish breeding and production and drought fallback security and tourism potential.

The region is characterized by profound situation of poverty and environmental fragility. The 20 million people have no alternative to Chad basin resources for their survival. Use, overuse and/or abuse of wetlands and their resources are deeply threatening wildlife and livelihoods because of the lowering of basin yields due to drought and human impacts. Lake Chad now covers merely 1,350 km2 (521 sq. miles) down from 25,000 km2 (9,653 sq miles) forty (40) years back.

Disturbed by these complex problems, the Heads of States and Governments of the Lake Chad Basin, namely Cameroon, Chad, Central African Republic, Niger, and Nigeria agreed to establish the Lake Chad Basin Commission in 1964 to encourage cooperation in developing the Lake Chad region and to attract financial and technical assistance for research and development. The recent program of action emphasized anti-desertification measures, coordinated protection of crops, animals and forestry, and of Lake Chad. Improvement in road and railway links between member countries is also a major concern of the commission.

The 8th Summit of the Commission held in Abuja in March, 1994 approved the document of the Master Plan for the Development and Environmentally Sound Management of the Natural Resources of the Lake Chad Conventional Basin. This document consisted of 36 projects relating to water resources, agriculture, forestry, biodiversity management, livestock, and fishery developments within the Lake Chad Conventional Basin.

It was at this summit that an international campaign to save Lake Chad was launched. The Summit instructed the executive secretariat to organize a donors' conference in consultation with United Nations' and other donor international organizations/agencies to mobilize international support for the implementation of the Commission's Master Plan.

SPECIAL WORK TEAM ON LAKE CHAD BASIN (ST-LCB) [IEC - Agenda, Minutes]

Lake Chad Basin - GIWA Regional Assessment 43

Report of the regional workshop on "developing guidelines for inter-basin water transfers for policy makers in Africa"

Presentation : Managing water resources of the Lake Chad Basin (Engr. Muhammad Sani Adamu)

Ecosystems Management in Africa – Case Study : Lake Chad River Basin Commission (Stephanie Hodge)

With a total area of about 1,335,000 square miles, the Congo basin consists of a vast shallow depression that rises by a series of giant steps to an almost circular rim of highlands through which the river has cut a narrow exit into the Atlantic Ocean. The present exit is geologically relatively recent, the previous exit being to the north of the present one.

The Congo River is some 2,900 miles in length. Its many waterfalls and rapids cause its valley, like that of the Nile, to lose elevation quickly. The river's course is often constricted by gorges. The best-known are the Boyoma (Stanley) Falls at Kisangani, where the river swings through an arc to flow westward; in fact, the Boyoma Falls are no more than a series of unevenly spaced rapids at no great height, extending along a 60-mile stretch of the river. Downstream from Kisangani, the Congo is joined first by the Ubangi from the right and then by the Kasai-which rivals the Ubangi in the size of its drainage basin-from the left. Below its confluence with the Kasai, the main river cuts through the Cristal Mountains in a deep gorge, which at one point expands into Malebo (Stanley) Pool, a shallow lake measuring 22 miles in length and 14 miles in width. The Congo enters the sea through a swampy estuary that is about 6 miles wide at its mouth.

The Niger basin is the largest river basin of western Africa. The Niger River, which rises in the mountains of Guinea, enters the sea through its delta in southern Nigeria; itis about 2,600 miles in length. Rapids interrupt its course at several points, although some of these (such as below Bamako, Mali) have been submerged in waters impounded by dams.

The Niger receives its largest tributary, the Benue, which flows in from its left bank, in Nigeria. The valleys of both the Niger downstream from Taoussa and the Benue appear to be faulted troughs dating from the Early Cretaceous Period. Originally, the middle Niger was separate from the upper Niger, which flowed into an inland lake, the remnants of which now form the inland Niger delta. The middle Niger flowed southeastward to the sea; its valley eroded toward its headwaters, eventually tapping the inland lake and linking the middle with the upper Niger.

There are two theories concerning the development of the Nile, which, it appears, originally consisted of two sections. The first theory is that the lower Nile had its source at about latitude 20° N, whence it flowed directly into the sea, while the upper Nile, issuing from Lake Victoria, flowed into an inland lake that covered the As-Sudd region in what is now The Sudan. The lake became filled with water, which then spilled over atits northern end and flowed into what is now the lower Nile. According to the second theory, the upper section originally flowed into a vast lake between Mount as Silsilah (near Luxor, Egypt) and what is now Asw(n; this was tapped by the lower section of the Nile after the so-called Sebile erosion (which takes its name from the fact that the breakthrough by the lower Nile was identified at Sebile).

The Nile, which is about 4,132 miles long, is the longest river in the world. From Lake Victoria it flows, as the Victoria Nile, into Lake Albert, from which it emerges as the Albert Nile. Farther north it is known as the Al-Jabal River. Thereafter, having received several tributaries, it becomes the White Nile, and finally the Nile, emptying at last into the Mediterranean Sea. Its major left-bank tributary is the Al-Ghaz(l, and the largest right-bank tributaries are the Sobat, Blue Nile, and Atbara. Because of the numerous rapids and waterfalls, the Nile descends fairly rapidly from source to mouth, as do its major right-bank tributaries. This is especially true of the Blue Nile, which, after issuing from Lake Tana on the Ethiopian Plateau at a height of approximately 6,000 feet, flows for most of its length through a steep gorge. Swamps also interrupt the river's course. Of these, the largest is the As-Sudd, a vast area of floating swamp reeds, mostly papyrus.

The river's regime is now controlled by a series of dams situated on the Nile itself or onone of its various tributaries; of these, the largest is the Aswan High Dam on the main Nile.

The Orange River is the longest in South Africa. Flowing across almost the entire widthof the country, it makes its way from the highlands in the east through the Kalahari depression in the west to empty into the South Atlantic Ocean. Its major tributary, the Vaal River, is one of its northern headwaters; the two rivers together have a combined length of about 1,300 miles. Together with other major rivers on the continent, the Orange-Vaal river system shares the characteristic of flowing over steep gradients for numerous stretches of its course. The largest drop (about 400 feet) occurs at the Augrabies Falls.

The Zambezi River is about 2,200 miles in length; it occupies a basin with an approximate area of 463,000 square miles. Originally, there were two rivers, corresponding to the upper and lower courses of the present river; the valley of the lower section eroded toward the headwaters until it captured the waters of the upper section. Although there are stretches of the river where the gradient is very gentle-a drop of only about three inches to the mile-the valley as a whole has a fairly steep gradient. There are numerous waterfalls, the most spectacular of which is the Victoria Falls. After these falls, the river winds through a number of deep gorges cut out of basalt and, after flowing through a broad valley, enters Kariba Gorge, which is more than 16 miles in length and is cut through paragneiss (a gneiss, or coarse-grained rock, in which bands rich in granular minerals alternate with bands containing schistose minerals, formed out of sedimentary rock). The Kafue and the Luangwa, the two main tributaries, which both flow through gorges, join the Zambezi on its left bank downstream from Kariba. At the mouth of the main river is a delta about 37 miles wide.