The Niger River, the main river of West Africa, stretches approximately 4,180 kilometers (2,600 miles). It is the third-longest river in Africa, after the Nile and the Congo. The Niger River begins in the Guinea Highlands in south-eastern Guinea near the Sierra Leone border. It flows in a crescent shape through Mali, Niger, on the border with Benin, and then through Nigeria, discharging through a massive delta, known as the Niger Delta, into the Gulf of Guinea in the Atlantic Ocean.
Along its course, the Niger is known by several names, including the Joliba (Malinke: “great river”) in its upper course; the Mayo Balleo and the Isa Eghirren in its central reach; and the Kwarra, Kworra, or Quorra in its lower stretch.
The river's drainage basin spans 2,117,700 km2 (817,600 sq mi) in area. The Niger River is a key water source for agriculture, fishing, and transportation in West Africa, supporting millions of people.
The Unique Course of the Niger River
The Niger River has a unique course. Instead of flowing directly to the ocean, it forms a large bend in Mali and Niger, creating an inland delta before turning south toward Nigeria, where it reaches the Atlantic. The Niger takes one of the most unusual routes of any major river, a boomerang shape that baffled geographers for two centuries.
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Its source (Tembakounda) is 240 km (150 mi) inland from the Atlantic Ocean, but the river runs directly away from the sea into the Sahara Desert, then takes a sharp right turn near the ancient city of Timbuktu and heads southeast to the Gulf of Guinea. This strange geography apparently came about because the Niger River is two ancient rivers joined together.
Physical Features and Physiography
The Niger rises in Guinea at 9°05′ N and 10°47′ W on the eastern side of the Fouta Djallon (Guinea) highlands, only 150 miles (240 km) inland from the Atlantic Ocean. Issuing as the Tembi from a deep ravine 2,800 feet (850 metres) above sea level, it flows due north over the first 100 miles (160 km).
It then follows a northeasterly direction, during the course of which it receives its upper tributaries-the Mafou, the Niandan, the Milo, and the Sankarani on the right and the Tinkisso on the left-and enters Mali. Just below Bamako, Mali’s capital, the Sotuba Dam marks the end of the upper river.
From there the Niger once dropped more than 1,000 feet (300 metres) in about 40 miles (60 km) into a valley formed by tectonic subsidence; but the rapids in this stretch have been submerged by the waters backed up by the Markala Dam, located some 150 miles (240 km) downstream of the Sotuba Dam near Sansanding. In this stretch, at Koulikoro, the river takes a more east-northeasterly direction, and its bed becomes fairly free from impediments for about 1,000 miles (1,600 km).
At Mopti the Niger is joined by the Bani, its largest tributary on the right, after which it enters a region of lakes, creeks, and backwaters that is often called the “internal delta” of the Niger. These lakes are chiefly on the left bank and are connected to the river by channels that undergo seasonal changes in the direction of flow. At high water most of the lakes become part of a general inundation. Largest of the lakes in this region is Lake Faguibine, which is nearly 75 miles (120 km) long, 15 miles (25 km) wide, and more than 160 feet (50 metres) deep in places.
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The labyrinth of lakes, creeks, and backwaters comes to an end at Kabara, the port of Timbuktu (Tombouctou). There, the river turns almost due east, passing its most northern point at latitude 17°05′ N. At low water the strong current there endangers navigation. A short way downstream the river turns to the southeast and widens considerably, flowing to Gao across a floodplain 3 to 6 miles (5 to 10 km) wide.
The middle course of the Niger River is navigable to small craft during high water as far downstream as Ansongo-some 1,100 miles (1,770 km) in all. Below Ansongo, 430 miles (690 km) downstream from Timbuktu, navigability is interrupted by a series of defiles and rapids. The river becomes navigable to small vessels again at Labbezanga-from which it flows into Niger-and continues to be navigable to the Atlantic Ocean.
Downstream from Jebba, in Nigeria, the Niger enters its lower course, flowing east-southeast through a broad and shallow valley 5 to 10 miles (8 to 16 km) wide. About 70 miles (110 km) from Jebba it is joined by the Kaduna River-an important tributary that contributes about one-fourth of the annual discharge of the river below the Niger-Kaduna confluence-and about 25 miles (40 km) above Lokoja the river turns to the south.
At Lokoja the river receives the water of its greatest tributary, the Benue, thereby approximately doubling the volume of its annual discharge. At their confluence the Niger is about three-fourths of a mile (1 km) wide, and the Benue more than a mile. Together they form a lakelike stretch of water about two miles wide that is dotted with islands and sandbanks.
From Lokoja downstream to the town of Idah, the Niger flows in a restricted valley, enclosed by hills and in some places flanked by sandstone cliffs up to 150 feet (45 metres) high. Between Idah and Onitsha the banks are lower and the country flatter. At Onitsha, the largest town on the Niger’s banks in Nigeria and the third largest riverine town after Bamako and Niamey (Niger), the valley narrows as the river flows through what is probably a fault in the area’s sandstone.
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It emerges at Aboh, separating into many branches before reaching the Gulf of Guinea via Africa’s largest delta. The Niger delta, which stretches for nearly 150 miles (240 km) from north to south and spreads along the coast for about 200 miles (320 km), extends over an area of 14,000 square miles (36,000 square km). Within the delta the river breaks up into an intricate network of channels called rivers. The Nun River is regarded as the direct continuation of the river, but some of the other important channels include (from west to east) the Forcados, the Brass, the Sambreiro, and the Bonny.
The Benue (meaning “Mother of Water” in the Batta language) rises at 4,400 feet (1,350 metres) above sea level on the Adamawa Plateau in northern Cameroon at about 7°40′ N and 13°15′ E. In its upper course, which extends north-northwest to its confluence with the Mayo Kébi, close to the town of Garoua, it is a mountain torrent, falling more than 2,000 feet (600 metres) over a distance of 110 miles (180 km). The river then turns westward into Nigeria and, for the greater part of its course, flows over a broad and fertile floodplain.
Together with its tributaries, the Niger drains a total area of some 730,000 square miles (1,900,000 square km). The Niger drainage system is bounded in the south by such highlands as the Fouta Djallon, the Banfora Cliffs in Burkina Faso, the Plateau of Yorubaland, and the Cameroon highlands. With the exception of such highlands as the Jos Plateau, the Iforas and Aïr massifs, and the Ahaggar Mountains to the north and east, the northern edge of the Niger basin is, however, less clearly defined than the southern edge.
Climate and Hydrology
Within the Niger basin, climate shows great variability. Mean annual precipitation levels decrease northward from more than 160 inches (4,100 mm) in the delta area to less than 10 inches (250 mm) in Timbuktu. Both the upper and the lower stretches of the river, however, drain areas with more than 50 inches (1,300 mm) of precipitation per year.
The middle Niger is an area where precipitation decreases and is also the sector where the greatest amount of evaporation takes place. It is estimated that in the lake region the Niger loses some two-thirds of the annual volume of discharge that flows past Mopti.
The great bend of the Niger River, seen from space, creates a green arc through the brown of the Sahel and Savanna. The river loses nearly two-thirds of its potential flow in the Inner Delta between Ségou and Timbuktu to seepage and evaporation. The water from the Bani River, which flows into the Delta at Mopti, does not compensate for the losses. The average loss is estimated at 31 km3/year but varies considerably between years.
The river is then joined by various tributaries but also loses more water to evaporation. The most important tributary is the Benue River which merges with the Niger at Lokoja in Nigeria.
The water in the Niger River basin is partially regulated through dams. In Mali the Sélingué Dam on the Sankarani River is mainly used for hydropower but also permits irrigation. The water resources of the Niger River are under pressure because of increased water abstraction for irrigation.
The Inland Delta of the Niger River
On the edge of the Sahara Desert lies one of the world’s most productive wetlands. The Inland Delta of the Niger River in Mali is a vast expanse of lakes, channels, and marshes. The Niger River divides into countless channels and forms the largest wetland in Western Africa.
This delta floods seasonally from September to December, as rainfall from the river’s headwaters in the Guinea Highlands reaches the delta’s vast flat floodplain. The southern part of the delta is low-lying floodplain with expanses of wetland grasses and reeds. The northern part has sand ridges that emerge from the water during the flood season. The seasonal flooding supports fisheries, pasture, and rice farming.
The Niger River and its Inner Delta are vital for agriculture, livestock, fisheries, transport, energy, tourism, and water filtration, as well as a habitat for a range of fish and other aquatic animals, including a variety of protected species.
Historical Significance
The Niger River has been central to West African civilizations for centuries. Ancient empires such as Ghana, Mali, and Songhai flourished along its banks. The ancient kingdoms of Gao and Mali emerged in the area, using the inland delta as a source of water, food, and commerce. The trading port of Timbuktu stands at the northeastern end of the delta.
The northern part of the river, known as the Niger bend, is an important area because it is the major river and source of water in that part of the Sahara. This made it the focal point of trade across the western Sahara and the centre of the Sahelian kingdoms of Mali and Gao.
Classical writings on the interior of the Sahara begin with Ptolemy, who mentions two rivers in the desert: the "Gir" (Γειρ) and farther south, the "Nigir" (Νιγειρ). The first has been since identified as the Wadi Ghir on the north-western edge of the Tuat, along the borders of modern Morocco and Algeria. While the true course of the Niger was presumably known to locals, it was a mystery to the outside world until the late 18th century.
Modern Importance and Challenges
The Niger River is a vital energy source for West Africa, with an installed hydropower capacity of 2,000 MW. However, only a fraction of its potential has been harnessed. However, there is still room for increasing energy production through the construction of further dams.
Environmental threats, such as mining and deforestation, pose risks to water quality. The diverse agroecological zones demand controlled irrigation, set to increase from 265,000 ha (2005) to 1.6 million ha by 2025.
The functionality of this vital system is not determined within Malian borders alone: nine countries share the Niger River Basin. Multiple uses and possible trade-offs need to be considered and assessed along this transboundary watershed, especially against the backdrop of climate change and demographic trends.
The World Bank Group is providing support to the Niger Basin Authority to strengthen well-informed decision making around the Fomi dam, in neighboring Guinea. The Fomi dam, to be built along the Niger River, is intended to increase the hydroelectric and irrigation potential of Guinea and Mali.
Unsurprisingly, the Niger Delta has been declared a wetland of international importance, or Ramsar site, hosting millions of migratory birds from Europe and further afield every year, as well as hippos and manatees.
During the flood months, the river is also a key transportation link, enabling the mobility that underpins economic activity. Approximately 40% of Mali's livestock migrate to the Delta region during the scorching dry months (over 2 million cows and 4 million goats and sheep). Freshwater fisheries provide additional food security. It is a regional safety valve given that livestock from Mauritania and Niger also flock to the Delta, following pastoralist traditions that stretch back for centuries.
The River Niger: West Africa's Lifeline
Key Data on the Niger River Basin
Here's a table summarizing key data related to the Niger River Basin:
| Parameter | Value |
|---|---|
| Length | 4,180 km (2,600 miles) |
| Drainage Basin Area | 2,117,700 km2 (817,600 sq mi) |
| Installed Hydropower Capacity | 2,000 MW |
| Flow in Koulikoro, Mali | 32.5 km³ per year (average 1970-1998) |
| Irrigation Potential | 2.8 million hectares |
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