Sanaga River

Sanaga River
The Sanaga River after the Edea Hydroelectric Power Station
Map of the Sanaga River drainage basin
Location
CountryCameroon
RegionsEast Region, Centre Region, Littoral Region
CitiesEdéa, Nanga Eboko, Bélabo
Physical characteristics
SourceConfluence of Djérem River and Lom River[1]
 • coordinates5°19′26″N 13°23′52″E / 5.323772°N 13.397769°E / 5.323772; 13.397769
 • elevation628 m (2,060 ft)
MouthBight of Biafra
 • coordinates
3°33′34″N 9°39′08″E / 3.559338°N 9.652175°E / 3.559338; 9.652175
 • elevation
0 m
Length603 km (375 mi), with Djérem River 1,067.5 km (663.3 mi)
Basin size
132,990 km2 (51,350 mi2)
Discharge 
 • locationEdéa
 • average1,985 m3/s (70,100 cu ft/s)
 • minimum234 m3/s (8,300 cu ft/s)
 • maximum6,950 m3/s (245,000 cu ft/s)
Discharge 
 • locationBight of Biafra, Cameroon (near mouth)
 • average2,072 m3/s (73,200 cu ft/s)[2]
 • minimum473 m3/s (16,700 cu ft/s)[2]
 • maximum5,700 m3/s (200,000 cu ft/s)[2]
Basin features
River systemSanaga River
Tributaries 
 • leftLong River, Tete River, Sele River, Mfam River, Ngoba River
 • rightMbam River, Mbuku River, Ligene River, Djam River, Dorong River, Jape River, Uem River
WaterbodiesSong Loulou Hydroelectric Power Station, Edea Hydroelectric Power Station
BridgesJapoma Bridge

The Sanaga River (formerly German: Zannaga) is the largest river in Cameroon located in East Region, Centre Region and Littoral Region. Its length is about 603 km (375 mi) from the confluence of Djérem and Lom River. The total length of Sanaga-Djérem River system is about 1,067.5 km (663.3 mi). Djérem is the longest source of Sanaga River with a total length of 464.5 km.

Course

The Sanaga River has its source at the Adamawa Plateau.[3] It is formed by the confluence of the Djérem and Lom Rivers in the north of the East Region. Djérem River has a total length of 464.5 km (288.6 mi) and Lom River a total length of 424.2 km (263.6 mi). Apart from these originating rivers, the largest tributary of the Sanaga is Mbam River with a total length of 548 km (341 mi).[4]

Slope of Sanaga River
Slope of Sanaga River[1]

Basin and Tributaries

The Sanaga river is situated in the central of Cameroon, and it is one of the essential headstreams, the Agoua and the Djérem meet to form the Sanaga which is about 56 miles (90km) north, northwest of Bertoua. The river then flows about 325 miles (525km) southwest across the central plateau past Nanga-Eboko, Djérem. It extends to a wide estuary that roughly bisects or divides Cameroon's Atlantic coastline 30 miles (48km) south of Douala.

Climate

The Sanaga River forms a boundary between two tropical moist forest ecoregions. The Cross-Sanaga-Bioko coastal forests lie to the north between the Sanaga River and the Cross River of Nigeria, and the Atlantic Equatorial coastal forests extend south of the river through southwestern Cameroon and Equatorial Guinea, Gabon, the Republic of the Congo, Cabinda and the Democratic Republic of the Congo.

Hydrology

The flow of the river was measured at Edéa in m3/s:[1]

0100020003000400050006000JanMarMayJulySeptNovdischarge in m³/s

Dams and reservoirs

Beginning at the headwaters, there are 2 dams on the Sanaga River:

Dam Nameplate capacity
(MW)
Reservoir Surface area
(km2)
Total capacity
(million m3)
Song Loulou 384 10
Edea 264

Impact of rainfall variability

The main forcing of river discharge variability is Climate change. However, having the comprehension of their simultaneous impacts on river discharges remains limited in some parts of the world like central Africa. The changes that occur in river discharges generally result from interactions between climate change and/or land-use changes, although it is also admitted that the physical characteristics of the watershed (size, slope system, type of soil, etc.) increase their sensitivity to these factors.[5]

Transport

Edea bridge on the Sanaga
Forest around the Sanaga River
Around the Sanaga River

Biodiversity and conservation

The Sanaga River supports one of Central Africa's richest freshwater ecosystems and contains numerous endemic fish species that are restricted to the Sanaga basin. The river also provides habitat for freshwater molluscs, aquatic plants, and migratory bird species associated with riparian wetlands.[6][7]

Hydroelectric development has modified sections of the river, particularly through the construction of dams such as Edéa, Song Loulou, Lom Pangar, and Nachtigal. While these projects contribute substantially to Cameroon's electricity production, they have also raised concerns regarding fish migration, sediment transport, and ecological connectivity.[8][9]

Conservation efforts increasingly focus on balancing hydropower production with environmental flow management and the protection of aquatic biodiversity throughout the Sanaga basin.[10][11]

References

  1. 1 2 3 PDF about the Hydrology of Cameroon (french)
  2. 1 2 3 "FAO".
  3. ↑ Knaap, M. van der (1994). Status of Fish Stocks and Fisheries of Thirteen Medium-sized African Reservoirs. Food & Agriculture Org. p. 11. ISBN 9789251035818.
  4. ↑ Runge, Jürgen (2012-05-30). Landscape Evolution, Neotectonics and Quaternary Environmental Change in Southern Cameroon: Palaeoecology of Africa Vol. 31, An International Yearbook of Landscape Evolution and Palaeoenvironments. CRC Press. p. 148. ISBN 9780415677356.
  5. ↑ "Impact of rainfall variability and land-use changes on river discharge in Sanaga catchment (forest–savannah transition zone in Central Africa)".
  6. ↑ Lévêque, C. (1992). The Fresh and Brackish Water Fishes of West Africa. IRD Editions.
  7. ↑ Stiassny, M. L. J. (2007). "Freshwater biodiversity in Africa". Annual Review of Ecology, Evolution, and Systematics.
  8. ↑ Lom Pangar Hydroelectric Project (Report). World Bank. 2012.
  9. ↑ Nachtigal Hydropower Project Environmental and Social Impact Assessment (Report). International Finance Corporation. 2018.
  10. ↑ Integrated Water Resources Management in Cameroon (Report). Global Water Partnership. 2020.
  11. ↑ Winemiller, K. O. (2016). "Balancing hydropower and biodiversity in tropical rivers". Science. 351 (6269): 128–129. doi:10.1126/science.aac7082.

Further reading

3°33′33.62″N 9°39′07.83″E / 3.5593389°N 9.6521750°E / 3.5593389; 9.6521750