African Unification Front
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AFRICA'S LARGEST WATERSHED
THE CONGO BASIN
Click on this line to see notes on the River Congo
Image of Africa's Densest Hydrographic Region
 This basin is the largest river basin in Africa, covering over 12% of the continent. It extends over nine countries and the largest area is in the DRC. With its tributaries it drains more than 4,100,000 square kilo-meters. The length of the Congo and its tributaries is 5,000 kilometers. Each second the Congo River pours 34,000 cubic meters of water into the Atlantic Ocean.
The basin extends west and north into Gabon, Cameroon, and the Central African Republic. To the south it reaches into Angola and Zambia; to the east, into Uganda, Rwanda, Burundi, and Tanzania. 99% of the DRC is located within the Congo Basin. About 75% of the state, which is over 170 million hectares, is covered by natural forest. Of these 170 million hectares, about 139 million hectares are considered exploitable and capable of producing 700 million m3 of industrial wood per year (or 5 m3 per ha). At present 0.5 million m3 per year is produced, managed by foreign logging firms. The area still has low infrastructure and transport. Of the remaining 63 million hectares, only 6 million ha is cultivated.
For some 320 kilometers upstream of Kisangani the Congo is about 6 to 14 kilometers wide. Most of the river's 4,000 islands are in this section. The river has cut deep into the ocean floor, and the brown of its silt-filled waters may be seen 50 kilometers out to sea.
The Congo River rises as two headstreams - the Luapula and the Lualaba. One of its other tributaries drains to Lake Tanganyika, estimated at 2 km3/year, and the Luapula drains to Lake Mweru, where the flow at the outlet is estimated at over 41 km3/year. The Luapula begins in a Zambian swamp fed by the Chambezi River. It flows northwest to Lake Mweru, emerges from the northern end of the lake as the Luvua, and continues northwest. The Lualaba drains the rich mining area of the Katanga in the southeast of the DRC. It flows north to meet the Luvua. Here the river is a 0.8 kilometer wide and 520 meters above sea level.
The Lualaba flows northward for 720 kilometers. The chief navigable tributaries of the Congo are the Kasai, Lomela, Lomami, and Ubangi. The Congo River basin spreads out from both sides of the equator. The basin receives up to 90 inches (230 centimeters) of rainfall a year. Tropical rain forests cover much of the land.
The flows in Burundi drain mainly into Lake Tanganyika and those in Rwanda into Lake Kivu, which is connected with Lake Tanganyika through the Rusizi river between the DRC, Rwanda and Burundi.
In the north about two-thirds of the Central African Republic lie within the Congo Basin. It is a humid region, with many sources flowing into the Oubangui River, a major tributary of the Congo River and forming the border between the CAR and the DRC. At Bangui, its discharge is estimated at over 126 km3/year.
The tributaries originating within Cameroon flow either to the Central African Republic in the east or to Congo in the south, where the discharge of the Sangha River at the border is over 52 km3/year. The Oubangui tributary forms the border between DRC and Congo-Brazaville, then flows into the Congo River which continues to be the border until the far south-west where it enters DRC. Many other tributaries originate in Congo.
To the south is Angola, where the Kasai River, another major tributary, originates together with many other smaller tributaries.
The discharge of the Congo River reaching Kinshasa and Brazzaville is about 1269 km3/year, which is equal to 32% of the renewable water resources for the whole of Africa. The river then continues to the south-west and forms the border between Angola and Zaire before flowing into the sea.
IRRIGATION POTENTIAL & WATER REQUIREMENTS
It is difficult to find reliable estimates of the irrigation potential of the very humid regions like the DRC, the Central African Republic, Congo-Brazaville, and Angola. In fact, neither water nor land is a limiting factor to agricultural development in these countries and other factors have to be taken into account in order to have some kind of realistic estimates of potential.
Zambia has a state water plan. The identified irrigation potential in the Congo basin in Zambia has been estimated at 101,000 ha, of which 15,000 ha by renewable groundwater and 20,000 ha of wetlands. The Luichi Delta near Kigoma on the shores of Lake Tanganyika contains a large area of good land which is seasonally flooded and unusable. Reclamation of 3000 ha has been proposed by means of a flood control dam and improved drainage.
For Burundi, about half of which is located in the Congo basin, the irrigation potential has been estimated at about 105,000 ha in the basin, of which 75000 ha for fully or partially controlled irrigation in the plains and the remaining area consisting of valley bottoms (bas-fonds). About 25 % of Rwanda is in the Congo basin and the irrigation potential here is estimated at 9000 ha, mainly consisting of valley bottoms.
Of the total irrigation potential of the Central African Republic, evaluated at 1.9 million hectares, about 1.4 million hectares are estimated to be within the Congo basin.
For Cameroon 50,000 ha are estimated to be in the Congo/Zaire basin. The
potential of Congo-Brazaville is estimated at between 40,000 and 340,000
ha, where the Congo basin occupies 75 % of the country.
Irrigation potential figures for the DRC vary between 4 and 20 million hectares. The total area cultivated at present is about 7 million ha. Land suitable for agriculture has been estimated at 80 million ha. When considering that no forest land will be converted into agricultural land, this area is reduced to 60 million ha, about half of which is used for other purposes. Like for Angola, the estimates for the irrigation potential are at 3% of the total area of the country, or 7 million ha. This area requires 108.50 km3/year of water for irrigation, which is about 12 % of the internal renewable water resources of Congo, estimated at 935 km3/year. Of these 7 million ha, 10,000 ha are considered to be in the Nile basin and 10,000 ha in the West Central Coast region. The remaining area, 6.98 million hectares, is considered to be in the Congo basin.
Angola has 6.7 million hectares with irrigation potential. According to the Direction of the Hydraulical Service about 420,000 ha could be irrigated at present, considering land and water as well as human resources. The irrigation potential is at about 3% of the area of the country, which corresponds to 3.7 million hectares. It has been distributed over the six basins on the basis of the percentage of the country covered by each basin, except for the Okavango and the South Interior, which are less humid than the other basins.
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