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Lake Chad

Lake Chad (Arabic: بحيرة تشاد, Kanuri: Sádǝ, French: Lac Tchad) is an endorheic freshwater lake located at the junction of four countries: Nigeria, Niger, Chad, and Cameroon in western and central Africa respectively, with a catchment area of 1×10^6 km2 (390,000 sq mi). It is an important wetland ecosystem in West-Central Africa. The lakeside is rich in reeds and swamps, and the plain along the lake is fertile, making it an important irrigated agricultural area. The lake is rich in aquatic resources and is one of the important freshwater fish producing areas in Africa.

Lake Chad
Lake Chad
Lake Chad
Lake Chad
Lake Chad
Lake Chad
LocationSahelian zone at the conjunction of Chad, Cameroon, Nigeria, and Niger
Primary inflowsChari River, Yobe River, Ngadda River
Primary outflowsBahr el-Ghazal
Basin countriesChad, Cameroon, Nigeria, Niger
Surface area2,000 km2 (770 sq mi)
Max. depth2 m (6 ft 7 in)
IslandsBogomerom Archipelago
Settlements
Official nameLac Tchad
Designated17 June 2001
Reference no.1072[1]
Official namePartie tchadienne du lac Tchad
Designated14 August 2001
Reference no.1134[2]
Official nameLake Chad Wetlands in Nigeria
Designated30 April 2008
Reference no.1749[3]
Official namePartie Camerounaise du Lac Tchad
Designated2 February 2010
Reference no.1903[4]

Lake Chad is divided into deeper southern parts and shallower northern parts. The water source of the lake mainly comes from rivers such as the Chari River that enter the lake. The water level varies greatly seasonally, and the area of the lake also changes dramatically. During the African humid period, the area of Lake Chad reached 400,000 km2 (150,000 sq mi). Due to the increasingly arid climate, the lake surface gradually shrank. In the 19th century, Lake Chad still had an area of 28,000 km2 (11,000 sq mi). However, due to climate change and human water diversion, Lake Chad has been greatly reduced since the mid-1970s, and its area has fluctuated between 2,000 and 5,000 km2 (770 and 1,930 sq mi).

Prehistory and history edit

 
Lake Chad in African humid period (blue) and in 20th century (green)

The Chad Basin was formed by the depression of the African Shield.[5][6][7] The floor of the basin is made of Precambrian bedrock covered by more than 3,600 m (11,800 ft) of sedimentary deposits.[8] For most of the Quaternary, the basin had abundant water sources. Towards the end of this period the climate became drier. Around 20,000-40,000 years ago, eolianite sand dunes began to form in the north of the basin.[9] The area of Lake Chad experienced four heydays between 39,000 BC and 300 BC, leaving thick diatomaceous earth and lacustrine deposits in the strata. This has been called Mega-Chad. The maximum depth of Mega-Chad exceeds 180 m (590 ft 7 in) and covers an area of approximately 400,000 km2 (150,000 sq mi),[5] flowed into the Benue River through the Mayo Kébbi, and finally flows into the Atlantic Ocean through the Niger River.[10][11]

The vast waters formed during the African humid period provided conditions for the emergence of lakeside fishermen's settlements, and the Nilo-Saharan ethnic group also migrated to Lake Chad during this period. Agriculture also emerged in the Sahel region at this time.[12] By 1800 BC, a pottery culture known as Gajiganna had emerged, initially as pastoralists, but, starting around 1500 BC, living in settled hamlets at the side of the lake.[13] The archaeological discovery revealed wild grasses, mostly of the tribe Paniceae, and wild rice together with the earliest domesticated Pearl millet in the Lake Chad region, dating to 1200-1000 cal BC. One of the oldest domesticated Pearl millet in West Africa was found in the Chad Basin, charred together with wild grasses, and their era can be traced back to 800-1000 cal BC.[14]

Permanent villages were established to the south of the lake by 500 BC,[15] and major archaeological discoveries include the Sao civilization.[5] According to the records of Claudius Ptolemy in the mid-2nd century AD, the Romans of the 1st century AD had already come into contact with Lake Chad through their connections with Tunisia, Tripolitania, and Fezzan.[16] By the 5th century AD camels were being used for trans-Saharan trade via the Fezzan, or to the east via Darfur.[17] After the Arabs conquered North Africa during the 7th and 8th centuries, the Chad Basin became increasingly linked to the Muslim countries.[15]

Trade and improved agricultural techniques enabled more sophisticated societies.[17] Around 900 AD, the Kanem people who spoke the Kanuri language unified numerous nomadic tribes and established the Kanem Empire in the northeast of Lake Chad. At the beginning of the founding of the country, the Kanem people continued to live a nomadic life until the 11th century, when they were Islamized and settled in Njimi. Through trans-Saharan trade, the power of the Kanem Empire reached its peak in the 13th century, but as the empire declined in the 14th century, its southwestern vassal state of Bornu began to rise, causing the power center of the empire to shift to Bornu around 1400. In the second half of the 16th century, the Bornu Empire began importing firearms from North Africa, consolidating its military hegemony. The Bornu Empire declined in the 18th century, and the rebellion of the Fulani herders caused Bornu to lose its western region and be conquered by France in the late 19th century.[18]

Following the growing interest in Africa among European academic and business communities, the Lake Chad area was extensively described by Europeans in the 19th century. Three scientific expeditions were conducted between 1898 and 1909.[5] During the Berlin Conference in 1884-1885, Africa was divided between the European colonial powers. By the second decade of the 20th century, Lake Chad had been colonized and occupied by Britain, France, and Germany, defining boundaries that are largely intact with the present post-colonial states.[19][20] At the beginning of independence, the countries surrounding Lake Chad not only had a poor economic foundation, but also had more complex ethnic, religious, and political conflicts. Nigeria and Niger, which had just gained independence, experienced continuous coups, while Chad also experienced ongoing civil war. The inability of countries along the lake to consider the protection of Lake Chad has led to a series of environmental problems.[20]

Geography edit

 
Map showing the Chari River drainage basin

The Chad Basin includes Chad, Nigeria, Cameroon, Niger, Sudan, and the Central African Republic.[21] It is an extensional fault depression type rift basin, which can be divided into four secondary structural units: southern depression, northern depression, central uplift, and eastern slope. The southern depression of the basin is characterized by an asymmetric fault depression composite rift with steep slopes in the east and gentle slopes in the west on the profile, and is distributed in an NNW direction on the plane. There are two large basin‐bounding normal fault developed on both sides of the basin, with a graben style fault and depression in the middle. The east and west sides are outward dipping low angle gentle slope areas. The eastern boundary fault is steep with a dip angle of about 55 °, while the western fault has a dip angle of about 45 °. The overall thickness of the inner layer in the slope area is relatively thin. In the central area of the basin, the thickness of the sedimentary strata is large, and the thickness of the sedimentary center zone reaches over 10,000 m (33,000 ft). The northern part of the basin appears steep in the west and gentle in the east on the profile. Five fault structural zones parallel to the basin‐bounding faults have developed from west to east.[22]

Lake Chad is divided into north and south parts by a shallow sill called the Great Barrier, with the bottom of the northern basin at an altitude of 275.3 m (903 ft) and the bottom of the southern basin at 278.2 m (913 ft). When the water level in the south exceeds 279 m (915 ft) above sea level, it will flow into the north.[23] In the south, there is continuous open water at the mouth of the Chari River, and the western part of the water is covered by reed swamps,[24] and the sand dunes that are not completely submerged in the eastern waters form an archipelago.[7] The average depth of the southern lake basin is between .5 and 2 m (1 ft 8 in and 6 ft 7 in), that of the northern lake basin is between 0 and 1.8 m (5 ft 11 in), and that of the eastern archipelago is between 0 and 2 m (6 ft 7 in).[25]

The climate of the Lake Chad region is strongly influenced by continental and maritime air masses. The maritime air mass moves northward during the summer, producing seasonal precipitation. In late summer, continental air mass dominate again.[5] The average annual precipitation in the Lake Chad area is 330 mm (13 in), with an average annual precipitation of 560 mm (22.0 in) on the south bank and about 250 mm (9.8 in) on the north bank. The highest temperature in the rainy season is 30 °C, and the highest temperature rises to more than 32 °C (90 °F) when October and November enter the dry season. The temperature difference between day and night is almost twice that of the rainy season, and the lowest nighttime temperature sometimes drops to 8 °C (46 °F) in December and January. April is usually the hottest month of the year, with temperatures occasionally reaching 40 °C (104 °F) , the lowest water levels appear in June to July, and the highest water levels in November to December, with surface water temperatures ranging from 19 to 32 °C (66 to 90 °F) .[5][7]

Hydrology edit

 
Shrinking of Lake Chad over the last 7000 years, with the outline of the British Isles for size comparison
 
Lake Chad 1972–2007

The Chad Basin covers an area of about 1×10^6 km2 (390,000 sq mi), and is injected by the Chari, Logone, and Yobe Rivers.[7][5] The water supply of the lake is seasonal. Most of the precipitation comes from the Adamawa Plateau in the south of the basin, which is transported to the lake basin through the Chari River and the Logone River. The two contribute 95% of the total inflow of Lake Chad, while the Yobe River only contributes less than 2.5%.[6] The lake seeps through the underground to the lowest point of the Chad Basin, the Bodélé Depression, approximately 480 km (300 mi) northeast of Lake Chad, with the deepest point reaching an elevation of only 155 m (509 ft) above sea level. This takes away most of the salinity and maintains the low salinity of Lake Chad. The southwestern waters of Lake Chad being freshwater, and the water in the northeast is only slightly salty.[26][6]

The water volume of most large lakes in Africa depends on rainfall and evaporation, which means that temperature and precipitation are crucial for regulating the water balance of these bodies of water, and any fluctuations can cause significant changes in their water level and area.[27] Lake Chad is a shallow inland lake, and the rainfall in the Chad basin is very sensitive to small changes in atmospheric circulation, so the surface area of Lake Chad is greatly affected by climate change.[28][29] Dry climate due to vegetation loss from overgrazing and deforestation and large-scale irrigation projects that diverted water from the rivers that feed the lake are the main reasons for the shrinkage of Lake Chad.[30] the Atlantic multidecadal oscillation and the El Niño–Southern Oscillation have affected precipitation in the Sahel region. From the early 1960s to the mid-1980s, the lake water level decreased by 3 m (9.8 ft) compared to the average level from 1900 to 2010.[31]

In 1870, the area of Lake Chad was about 28,000 km2 (11,000 sq mi). The lake was able to flow out of the Bahr el-Ghazal during the rainy season. At the turn of the 20th century the area of Lake Chad shrank briefly, and reached a new high in the middle of the 20th century and overflowed from the Bahr el-Ghazal again.[5] A major drought started in the Sahel region in the late 1960s and caused severe damage in 1972 and 1984. It was thought to be related to vegetation loss, global warming, and sea surface temperature anomalies.[28] During this period, Lake Chad shrunk considerably and fluctuated in the range of 2,000 to 5,000 km2 (770 to 1,930 sq mi) thereafter.[23]

From June 1966 to January 1973, the area of Lake Chad shrank from 22,772 to 15,400 km2 (8,792 to 5,946 sq mi),[30] further shrunk to 4,398 km2 (1,698 sq mi) in 1975,[23] and only 1,756 km2 (678 sq mi) in February 1994.[30] Since then, the area of Lake Chad has entered a relatively stable stage with a slight increase.[32] From 1995 to 1998, it fluctuated within the range of 1,200 to 4,500 km2 (460 to 1,740 sq mi). The area once reached 5,075 square kilometres (1,959 sq mi) in 2000,[23] and the average area of surface water from 2013 to 2016 was about 1,876 km2 (724 sq mi), with the largest area being 2,231 km2 (861 sq mi) in July 2015.[33]

Ecology edit

 
Lake Chad flooded savanna

Part of the Chad Basin is located within the Chad Basin National Park in Nigeria, and the country and Cameroon have established the Lake Chad Ramsar Wetland with a total area of 8,225 km2 (3,176 sq mi).[34] The wetland plants in the south mainly include cyperus papyrus, etc. Reeds mainly grow in the north where the salinity is high, and the floating plant pistia sometimes covers large areas of open water. Plants such as hyparrhenia rufa grow on the shores of lakes with long floods in the south.[34] The area of permanent vegetation has increased from about 3,800 km2 (1,500 sq mi) in 2000 to about 5,200 km2 (2,000 sq mi) in 2020 as water levels have dropped and temperatures have increased.[35] The surrounding dense woodland has been converted to open forest with acacias, baobabs, palms and Indian jujube.[5]

Lake Chad is permanently or seasonally inhabited by hundreds of species of birds such as northern shoveler, Egyptian goose and marabou stork.[5] It is an important wintering ground for European anatididae and wading birds. There are raptors such as steppe eagle and booted eagle on the lakeshore,[34] and more than one million ruff can be observed on the lake at one time.[36] The once common large mammals include red-fronted gazelle, dama gazelle, patas monkey, striped hyena, cheetah and caracal, while African elephant, otter, hippopotamus, sitatunga and kob are distributed in the wetlands. At present, most of the large mammals have been hunted to extinction, replaced by a large number of cattle.[34]

The entire Chad Basin has 179 species of fish, of which 127 are the same as the Niger River Basin, 85 are the same as the Nile River Basin, 47 are the same as the Congo River Basin, and 84 fish species are distributed in the lake.[6] This makes it a rich fishing ground for communities across Nigeria, Niger, Chad, and Cameroon. The seasonal influx of floods combined with seasonal increases in air temperature leads to decreased salinity, increased turbidity, and increased trophic levels, which catalyzed a surge in the number of phytoplankton and zooplankton, allowing large fish to migrate seasonally within the watershed to feed and breed in the fertile floodplain when floods arrive.[24]

Human activities edit

 
Building a temporary house in Lake Chad region

There are more than 30 million residents in the Chad Lake Basin. There are more than 70 ethnic groups around the lake, most of whom are distributed on the south bank, where the population density exceeds 100/km2 (260/sq mi). They rely on the water source of Chad Lake for irrigation, breeding, animal husbandry and drinking.[26] Local self-sufficient crops include sorghum, maize, finger millet, beans, and vegetables. Gourd is widely planted for making utensils. The collection of forest products such as gum arabic, honey, beeswax, and firewood is of great significance in the region. However, the reduction in forest area has had a negative impact on the production of these products, and the explosive growth of cattle herds has exacerbated this impact. Cattle are the most important livestock raised, as well as poultry, goats, sheep, camels, horses, and donkeys. The animal husbandry was severely affected by the droughts of the 1970s and 1980s.[5]

Fishing has traditionally been the most important economic activity for the people of the lake area, which almost ceased during drought periods and only resumed in the mid-1990s. Most fishing products are dried, pickled, or smoked. The natron produced in the depression on the northeast bank of the lake has long been of significant economic significance. Traditionally, it has been excavated in blocks and transported across the lake to enter the Nigerian market.[5] Since the drought in the 1970s, the soil that can be planted without irrigation and fertilization has been exposed at the bottom of the lake, and it has been reclaimed as a polder for planting maize, cowpea, rice, sorghum and other crops.[37] Farmers have shifted from planting mainly dry crops, such as wheat, to rice with high water demand, resulting in more serious soil salinization and water eutrophication.[26] The adverse effects of reduced water sources on fishing, farming, and herding outweigh the benefits of new land from the receding waters. The surrounding residents who used to rely on lake water were forced to relocate, causing the economy of the lake area to continuously shrink.[38]

Since 1970, five countries in the southern part of the basin have constructed numerous water conservancy projects in the upper reaches of the Chari River, Logone River, and Yobe River to intercept river water, resulting in a sharp decrease in the amount of water entering the lake. The average annual inflow of the Chari River and the Logone River from 1970 to 1990 was only 55% of that from 1950 to 1970. Since the 1980s, one-third of the water in the Chari River and the Logone River has been diverted and intercepted by the Central African Republic located upstream for agricultural irrigation and hydroelectric power generation.[26] The dams built on the upper reaches of the rivers entering the lake changed the time and scope of seasonal floods and disrupted the migration of fish, resulting in a sharp reduction in the populations of Alestes baremoze and Nile perch, the main catches of Lake Chad, and a significant reduction in the catch.[36][6] At the same time, the conflicts between countries and ethnic groups competing for water and land are also escalating. The four countries along the lake are all facing the problem of extreme poverty, and due to the difficulty in meeting their livelihoods, some local residents have been involved in drug and arms trade.[26] This has been exacerbated by the activity of Boko Haram, an insurgency that has displaced millions of people and disrupted development through the region.[39]

Cameroon, Niger, Nigeria, and Chad established the Lake Chad Basin Commission on 22 May 1964. The Central African Republic joined in 1996, and Libya joined in 2008. The headquarters of the committee is located in N'Djamena, Chad. The commission's tasks include managing Lake Chad and its water resources, protecting the ecosystem, and promoting regional integration, peace, security, and development in the Lake Chad region.[40] The surrounding countries' water replenishment plan for Lake Chad includes the construction of a 2,400 km (1,500 mi) canal to transport 100×10^9 m3 (130×10^9 cu yd) of water from the Congo River Basin to the Chari River Basin every year, and use a series of dams along the route to generate electricity.[41]

See also edit

References edit

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  2. ^ "Partie tchadienne du lac Tchad". Ramsar Sites Information Service. from the original on 23 June 2018. Retrieved 25 April 2018.
  3. ^ "Lake Chad Wetlands in Nigeria". Ramsar Sites Information Service. from the original on 23 June 2018. Retrieved 25 April 2018.
  4. ^ "Partie Camerounaise du Lac Tchad". Ramsar Sites Information Service. from the original on 1 February 2020. Retrieved 25 April 2018.
  5. ^ a b c d e f g h i j k l Gritzner, J. A. "Lake Chad". Encyclopedia Britannica. Chicago: Encyclopædia Britannica, Inc. from the original on 22 July 2019. Retrieved 13 June 2023.
  6. ^ a b c d e Hughes, R. H.; Hughes, J. S. (1992). A Directory of African Wetlands (PDF). IUCN / UNEP / WCMC. pp. 329–330. ISBN 2-88032-949-3. (PDF) from the original on 24 September 2012. Retrieved 14 June 2023.
  7. ^ a b c d Wen Yunzhao. "Lake Chad". Encyclopedia of China (in Chinese (China)) (03 ed.). Beijing: Encyclopedia of China Publishing House. from the original on 13 June 2023. Retrieved 11 June 2023.
  8. ^ Obaje, Nuhu George (12 August 2009). Geology and Mineral Resources of Nigeria. Springer. p. 69. ISBN 978-3-540-92684-9. Retrieved 6 May 2013.
  9. ^ Wright, J.B. (30 November 1985). Geology and Mineral Resources of West Africa. Springer. p. 95. ISBN 978-0-04-556001-1. Retrieved 6 May 2013.
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  14. ^ Marlies Klee; Barbara Zach (1999). "The Exploitation of Wild and Domesticated Food Plants at Settlement Mounds in North-East Nigeria (1800 cal BC to Today)". The Exploitation of Plant Resources in Ancient Africa: 81–88. doi:10.1007/978-1-4757-6730-8_8.
  15. ^ a b Decorse, Christopher R. (2001). West Africa During the Atlantic Slave Trade: Archaeological Perspectives. Continuum International Publishing Group. p. 103. ISBN 978-0-7185-0247-8. Retrieved 6 May 2013.
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  17. ^ a b Appiah, Kwame Anthony; Gates, Henry Louis Jr. (2010). Encyclopaedia of Africa. Oxford University Press. p. 254. ISBN 978-0-19-533770-9. Retrieved 6 May 2013.
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  19. ^ Harlow, Barbara (2003). "Conference of Berlin (1884–1885)". Colonialism. ABC-CLIO. p. 139. ISBN 978-1-57607-335-3. Retrieved 6 May 2013.
  20. ^ a b 熊正坤; 张瑾 (8 April 2021). "乍得湖:从"文明摇篮"到"死亡之心"" [Lake Chad: From "Cradle of Civilization" to "Heart of Death"]. China Water Resources News. from the original on 1 January 2024. Retrieved 1 January 2024.
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  22. ^ 黄先雄; 夏斌; 万志峰; 吕宝凤; 蔡周荣 (2008). "乍得湖盆地构造特征与油气成藏规律初探" [A preliminary study on the tectonic characteristics and hydrocarbon accumulation law of the Lake Chad Basin]. 大地构造与成矿学 (03): 326–331. doi:10.16539/j.ddgzyckx.2008.03.013.
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  29. ^ Leblanc, M.; Favreau, G.; Tweed, S. (2007). "Remote sensing for groundwater modelling in large semiarid areas:Lake Chad Basin, Africa". Hydrogeology Journal. 15: 97–100. doi:10.1007/s10040-006-0126-0.
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  33. ^ Willibroad Gabila Buma; Sang-Il Lee; Jae Young Seo (2018). "Recent surface water extent of Lake Chad from multispectral sensors and GRACE". Sensors. 18 (7): 2082. doi:10.3390/s18072082. PMC 6069056. PMID 29958481.
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  35. ^ Binh Pham-Duc; Florence Sylvestre; Fabrice Papa; Frédéric Frappart; Camille Bouchez; Jean-Francois Crétaux (2020). "The Lake Chad hydrology under current climate change". Scientific Reports. 10 (5498). doi:10.1038/s41598-020-62417-w. PMC 7099084.
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  37. ^ Luxereau, A.; Genthon, P.; Ambouta, J.-M. K. (2011). . Regional Environmental Change. 12 (3): 507–521. doi:10.1007/s10113-011-0267-0. Archived from the original on 14 June 2023. Retrieved 13 June 2023.
  38. ^ Roman D. Zarate; Remi Jedwab; Federico Haslop; Carlos Rodríguez-Castelán (5 September 2023). "The Effects of Climate Change in the Poorest Countries: Evidence from the Permanent Shrinking of Lake Chad". World Bank. Retrieved 8 April 2024.
  39. ^ Olowoyeye, Oluwatuyi S.; Kanwar, Rameshwar S. (2023). "Water and Food Sustainability in the Riparian Countries of Lake Chad in Africa". Sustainability. 15 (13): 10009:2. doi:10.3390/su151310009.
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Further reading edit

  • Hughes, R. H.; Hughes, J. S. (1992). A Directory of African Wetlands. IUCN. ISBN 978-2-88032-949-5.
  • Beadle, L. C. (1974). The Inland Waters of Tropical Africa: An Introduction to Tropical Limnology Hardcover (1th ed.). Longman Publishing Group. ISBN 978-0582448520.
  • Chapman, Graham; Baker, Kathleen M. (1992). The changing geography of Africa and the Middle East. Routledge. ISBN 9780203034507.
  • Caterina Batello; Marzio Marzot; Adamou Harouna Touré (2004). The Future is an Ancient Lake. FAO Interdepartmental Working Group on Biological Diversity for Food and Agriculture. ISBN 92-5-105064-3.

External links edit

  • Lake Chad Basin Commission
  • BIOsphere and Heritage of Lake Chad (BIOPALT) project
  • The Ups and Downs of Lake Chad
  • Lake Chad in worldlakes.org
  • Lake Chad in World Lake Database
  • Lake Chad | UN News

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This article is about the lake in Africa For the lake in Antarctica see Lake Chad Antarctica Lake Chad Arabic بحيرة تشاد Kanuri Sadǝ French Lac Tchad is an endorheic freshwater lake located at the junction of four countries Nigeria Niger Chad and Cameroon in western and central Africa respectively with a catchment area of 1 10 6 km2 390 000 sq mi It is an important wetland ecosystem in West Central Africa The lakeside is rich in reeds and swamps and the plain along the lake is fertile making it an important irrigated agricultural area The lake is rich in aquatic resources and is one of the important freshwater fish producing areas in Africa Lake Chadبحيرة تشاد Arabic Sadǝ Kanuri Lac Tchad French Lake ChadShow map of ChadLake ChadShow map of CameroonLake ChadShow map of NigerLake ChadShow map of NigeriaLake ChadShow map of AfricaLocationSahelian zone at the conjunction of Chad Cameroon Nigeria and NigerPrimary inflowsChari River Yobe River Ngadda RiverPrimary outflowsBahr el GhazalBasin countriesChad Cameroon Nigeria NigerSurface area2 000 km2 770 sq mi Max depth2 m 6 ft 7 in IslandsBogomerom ArchipelagoSettlementsBol Chad Abadam Nigeria Baga Nigeria N guigmi Niger Bosso Niger Makary CameroonRamsar WetlandOfficial nameLac TchadDesignated17 June 2001Reference no 1072 1 Ramsar WetlandOfficial namePartie tchadienne du lac TchadDesignated14 August 2001Reference no 1134 2 Ramsar WetlandOfficial nameLake Chad Wetlands in NigeriaDesignated30 April 2008Reference no 1749 3 Ramsar WetlandOfficial namePartie Camerounaise du Lac TchadDesignated2 February 2010Reference no 1903 4 Lake Chad is divided into deeper southern parts and shallower northern parts The water source of the lake mainly comes from rivers such as the Chari River that enter the lake The water level varies greatly seasonally and the area of the lake also changes dramatically During the African humid period the area of Lake Chad reached 400 000 km2 150 000 sq mi Due to the increasingly arid climate the lake surface gradually shrank In the 19th century Lake Chad still had an area of 28 000 km2 11 000 sq mi However due to climate change and human water diversion Lake Chad has been greatly reduced since the mid 1970s and its area has fluctuated between 2 000 and 5 000 km2 770 and 1 930 sq mi Contents 1 Prehistory and history 2 Geography 3 Hydrology 4 Ecology 5 Human activities 6 See also 7 References 8 Further reading 9 External linksPrehistory and history edit nbsp Lake Chad in African humid period blue and in 20th century green The Chad Basin was formed by the depression of the African Shield 5 6 7 The floor of the basin is made of Precambrian bedrock covered by more than 3 600 m 11 800 ft of sedimentary deposits 8 For most of the Quaternary the basin had abundant water sources Towards the end of this period the climate became drier Around 20 000 40 000 years ago eolianite sand dunes began to form in the north of the basin 9 The area of Lake Chad experienced four heydays between 39 000 BC and 300 BC leaving thick diatomaceous earth and lacustrine deposits in the strata This has been called Mega Chad The maximum depth of Mega Chad exceeds 180 m 590 ft 7 in and covers an area of approximately 400 000 km2 150 000 sq mi 5 flowed into the Benue River through the Mayo Kebbi and finally flows into the Atlantic Ocean through the Niger River 10 11 The vast waters formed during the African humid period provided conditions for the emergence of lakeside fishermen s settlements and the Nilo Saharan ethnic group also migrated to Lake Chad during this period Agriculture also emerged in the Sahel region at this time 12 By 1800 BC a pottery culture known as Gajiganna had emerged initially as pastoralists but starting around 1500 BC living in settled hamlets at the side of the lake 13 The archaeological discovery revealed wild grasses mostly of the tribe Paniceae and wild rice together with the earliest domesticated Pearl millet in the Lake Chad region dating to 1200 1000 cal BC One of the oldest domesticated Pearl millet in West Africa was found in the Chad Basin charred together with wild grasses and their era can be traced back to 800 1000 cal BC 14 Permanent villages were established to the south of the lake by 500 BC 15 and major archaeological discoveries include the Sao civilization 5 According to the records of Claudius Ptolemy in the mid 2nd century AD the Romans of the 1st century AD had already come into contact with Lake Chad through their connections with Tunisia Tripolitania and Fezzan 16 By the 5th century AD camels were being used for trans Saharan trade via the Fezzan or to the east via Darfur 17 After the Arabs conquered North Africa during the 7th and 8th centuries the Chad Basin became increasingly linked to the Muslim countries 15 Trade and improved agricultural techniques enabled more sophisticated societies 17 Around 900 AD the Kanem people who spoke the Kanuri language unified numerous nomadic tribes and established the Kanem Empire in the northeast of Lake Chad At the beginning of the founding of the country the Kanem people continued to live a nomadic life until the 11th century when they were Islamized and settled in Njimi Through trans Saharan trade the power of the Kanem Empire reached its peak in the 13th century but as the empire declined in the 14th century its southwestern vassal state of Bornu began to rise causing the power center of the empire to shift to Bornu around 1400 In the second half of the 16th century the Bornu Empire began importing firearms from North Africa consolidating its military hegemony The Bornu Empire declined in the 18th century and the rebellion of the Fulani herders caused Bornu to lose its western region and be conquered by France in the late 19th century 18 Following the growing interest in Africa among European academic and business communities the Lake Chad area was extensively described by Europeans in the 19th century Three scientific expeditions were conducted between 1898 and 1909 5 During the Berlin Conference in 1884 1885 Africa was divided between the European colonial powers By the second decade of the 20th century Lake Chad had been colonized and occupied by Britain France and Germany defining boundaries that are largely intact with the present post colonial states 19 20 At the beginning of independence the countries surrounding Lake Chad not only had a poor economic foundation but also had more complex ethnic religious and political conflicts Nigeria and Niger which had just gained independence experienced continuous coups while Chad also experienced ongoing civil war The inability of countries along the lake to consider the protection of Lake Chad has led to a series of environmental problems 20 Geography edit nbsp Map showing the Chari River drainage basin The Chad Basin includes Chad Nigeria Cameroon Niger Sudan and the Central African Republic 21 It is an extensional fault depression type rift basin which can be divided into four secondary structural units southern depression northern depression central uplift and eastern slope The southern depression of the basin is characterized by an asymmetric fault depression composite rift with steep slopes in the east and gentle slopes in the west on the profile and is distributed in an NNW direction on the plane There are two large basin bounding normal fault developed on both sides of the basin with a graben style fault and depression in the middle The east and west sides are outward dipping low angle gentle slope areas The eastern boundary fault is steep with a dip angle of about 55 while the western fault has a dip angle of about 45 The overall thickness of the inner layer in the slope area is relatively thin In the central area of the basin the thickness of the sedimentary strata is large and the thickness of the sedimentary center zone reaches over 10 000 m 33 000 ft The northern part of the basin appears steep in the west and gentle in the east on the profile Five fault structural zones parallel to the basin bounding faults have developed from west to east 22 Lake Chad is divided into north and south parts by a shallow sill called the Great Barrier with the bottom of the northern basin at an altitude of 275 3 m 903 ft and the bottom of the southern basin at 278 2 m 913 ft When the water level in the south exceeds 279 m 915 ft above sea level it will flow into the north 23 In the south there is continuous open water at the mouth of the Chari River and the western part of the water is covered by reed swamps 24 and the sand dunes that are not completely submerged in the eastern waters form an archipelago 7 The average depth of the southern lake basin is between 5 and 2 m 1 ft 8 in and 6 ft 7 in that of the northern lake basin is between 0 and 1 8 m 5 ft 11 in and that of the eastern archipelago is between 0 and 2 m 6 ft 7 in 25 The climate of the Lake Chad region is strongly influenced by continental and maritime air masses The maritime air mass moves northward during the summer producing seasonal precipitation In late summer continental air mass dominate again 5 The average annual precipitation in the Lake Chad area is 330 mm 13 in with an average annual precipitation of 560 mm 22 0 in on the south bank and about 250 mm 9 8 in on the north bank The highest temperature in the rainy season is 30 C and the highest temperature rises to more than 32 C 90 F when October and November enter the dry season The temperature difference between day and night is almost twice that of the rainy season and the lowest nighttime temperature sometimes drops to 8 C 46 F in December and January April is usually the hottest month of the year with temperatures occasionally reaching 40 C 104 F the lowest water levels appear in June to July and the highest water levels in November to December with surface water temperatures ranging from 19 to 32 C 66 to 90 F 5 7 Hydrology edit nbsp Shrinking of Lake Chad over the last 7000 years with the outline of the British Isles for size comparison nbsp Lake Chad 1972 2007 The Chad Basin covers an area of about 1 10 6 km2 390 000 sq mi and is injected by the Chari Logone and Yobe Rivers 7 5 The water supply of the lake is seasonal Most of the precipitation comes from the Adamawa Plateau in the south of the basin which is transported to the lake basin through the Chari River and the Logone River The two contribute 95 of the total inflow of Lake Chad while the Yobe River only contributes less than 2 5 6 The lake seeps through the underground to the lowest point of the Chad Basin the Bodele Depression approximately 480 km 300 mi northeast of Lake Chad with the deepest point reaching an elevation of only 155 m 509 ft above sea level This takes away most of the salinity and maintains the low salinity of Lake Chad The southwestern waters of Lake Chad being freshwater and the water in the northeast is only slightly salty 26 6 The water volume of most large lakes in Africa depends on rainfall and evaporation which means that temperature and precipitation are crucial for regulating the water balance of these bodies of water and any fluctuations can cause significant changes in their water level and area 27 Lake Chad is a shallow inland lake and the rainfall in the Chad basin is very sensitive to small changes in atmospheric circulation so the surface area of Lake Chad is greatly affected by climate change 28 29 Dry climate due to vegetation loss from overgrazing and deforestation and large scale irrigation projects that diverted water from the rivers that feed the lake are the main reasons for the shrinkage of Lake Chad 30 the Atlantic multidecadal oscillation and the El Nino Southern Oscillation have affected precipitation in the Sahel region From the early 1960s to the mid 1980s the lake water level decreased by 3 m 9 8 ft compared to the average level from 1900 to 2010 31 In 1870 the area of Lake Chad was about 28 000 km2 11 000 sq mi The lake was able to flow out of the Bahr el Ghazal during the rainy season At the turn of the 20th century the area of Lake Chad shrank briefly and reached a new high in the middle of the 20th century and overflowed from the Bahr el Ghazal again 5 A major drought started in the Sahel region in the late 1960s and caused severe damage in 1972 and 1984 It was thought to be related to vegetation loss global warming and sea surface temperature anomalies 28 During this period Lake Chad shrunk considerably and fluctuated in the range of 2 000 to 5 000 km2 770 to 1 930 sq mi thereafter 23 From June 1966 to January 1973 the area of Lake Chad shrank from 22 772 to 15 400 km2 8 792 to 5 946 sq mi 30 further shrunk to 4 398 km2 1 698 sq mi in 1975 23 and only 1 756 km2 678 sq mi in February 1994 30 Since then the area of Lake Chad has entered a relatively stable stage with a slight increase 32 From 1995 to 1998 it fluctuated within the range of 1 200 to 4 500 km2 460 to 1 740 sq mi The area once reached 5 075 square kilometres 1 959 sq mi in 2000 23 and the average area of surface water from 2013 to 2016 was about 1 876 km2 724 sq mi with the largest area being 2 231 km2 861 sq mi in July 2015 33 Ecology edit nbsp Lake Chad flooded savanna Part of the Chad Basin is located within the Chad Basin National Park in Nigeria and the country and Cameroon have established the Lake Chad Ramsar Wetland with a total area of 8 225 km2 3 176 sq mi 34 The wetland plants in the south mainly include cyperus papyrus etc Reeds mainly grow in the north where the salinity is high and the floating plant pistia sometimes covers large areas of open water Plants such as hyparrhenia rufa grow on the shores of lakes with long floods in the south 34 The area of permanent vegetation has increased from about 3 800 km2 1 500 sq mi in 2000 to about 5 200 km2 2 000 sq mi in 2020 as water levels have dropped and temperatures have increased 35 The surrounding dense woodland has been converted to open forest with acacias baobabs palms and Indian jujube 5 Lake Chad is permanently or seasonally inhabited by hundreds of species of birds such as northern shoveler Egyptian goose and marabou stork 5 It is an important wintering ground for European anatididae and wading birds There are raptors such as steppe eagle and booted eagle on the lakeshore 34 and more than one million ruff can be observed on the lake at one time 36 The once common large mammals include red fronted gazelle dama gazelle patas monkey striped hyena cheetah and caracal while African elephant otter hippopotamus sitatunga and kob are distributed in the wetlands At present most of the large mammals have been hunted to extinction replaced by a large number of cattle 34 The entire Chad Basin has 179 species of fish of which 127 are the same as the Niger River Basin 85 are the same as the Nile River Basin 47 are the same as the Congo River Basin and 84 fish species are distributed in the lake 6 This makes it a rich fishing ground for communities across Nigeria Niger Chad and Cameroon The seasonal influx of floods combined with seasonal increases in air temperature leads to decreased salinity increased turbidity and increased trophic levels which catalyzed a surge in the number of phytoplankton and zooplankton allowing large fish to migrate seasonally within the watershed to feed and breed in the fertile floodplain when floods arrive 24 Human activities edit nbsp Building a temporary house in Lake Chad region There are more than 30 million residents in the Chad Lake Basin There are more than 70 ethnic groups around the lake most of whom are distributed on the south bank where the population density exceeds 100 km2 260 sq mi They rely on the water source of Chad Lake for irrigation breeding animal husbandry and drinking 26 Local self sufficient crops include sorghum maize finger millet beans and vegetables Gourd is widely planted for making utensils The collection of forest products such as gum arabic honey beeswax and firewood is of great significance in the region However the reduction in forest area has had a negative impact on the production of these products and the explosive growth of cattle herds has exacerbated this impact Cattle are the most important livestock raised as well as poultry goats sheep camels horses and donkeys The animal husbandry was severely affected by the droughts of the 1970s and 1980s 5 Fishing has traditionally been the most important economic activity for the people of the lake area which almost ceased during drought periods and only resumed in the mid 1990s Most fishing products are dried pickled or smoked The natron produced in the depression on the northeast bank of the lake has long been of significant economic significance Traditionally it has been excavated in blocks and transported across the lake to enter the Nigerian market 5 Since the drought in the 1970s the soil that can be planted without irrigation and fertilization has been exposed at the bottom of the lake and it has been reclaimed as a polder for planting maize cowpea rice sorghum and other crops 37 Farmers have shifted from planting mainly dry crops such as wheat to rice with high water demand resulting in more serious soil salinization and water eutrophication 26 The adverse effects of reduced water sources on fishing farming and herding outweigh the benefits of new land from the receding waters The surrounding residents who used to rely on lake water were forced to relocate causing the economy of the lake area to continuously shrink 38 Since 1970 five countries in the southern part of the basin have constructed numerous water conservancy projects in the upper reaches of the Chari River Logone River and Yobe River to intercept river water resulting in a sharp decrease in the amount of water entering the lake The average annual inflow of the Chari River and the Logone River from 1970 to 1990 was only 55 of that from 1950 to 1970 Since the 1980s one third of the water in the Chari River and the Logone River has been diverted and intercepted by the Central African Republic located upstream for agricultural irrigation and hydroelectric power generation 26 The dams built on the upper reaches of the rivers entering the lake changed the time and scope of seasonal floods and disrupted the migration of fish resulting in a sharp reduction in the populations of Alestes baremoze and Nile perch the main catches of Lake Chad and a significant reduction in the catch 36 6 At the same time the conflicts between countries and ethnic groups competing for water and land are also escalating The four countries along the lake are all facing the problem of extreme poverty and due to the difficulty in meeting their livelihoods some local residents have been involved in drug and arms trade 26 This has been exacerbated by the activity of Boko Haram an insurgency that has displaced millions of people and disrupted development through the region 39 Cameroon Niger Nigeria and Chad established the Lake Chad Basin Commission on 22 May 1964 The Central African Republic joined in 1996 and Libya joined in 2008 The headquarters of the committee is located in N Djamena Chad The commission s tasks include managing Lake Chad and its water resources protecting the ecosystem and promoting regional integration peace security and development in the Lake Chad region 40 The surrounding countries water replenishment plan for Lake Chad includes the construction of a 2 400 km 1 500 mi canal to transport 100 10 9 m3 130 10 9 cu yd of water from the Congo River Basin to the Chari River Basin every year and use a series of dams along the route to generate electricity 41 See also edit nbsp Lakes portal nbsp Earth sciences portal nbsp Water portal Inner Niger Delta an inland delta in Mali Lake Ptolemy former lake in Sudan List of drying lakes Sudd vast swamp in South Sudan Wildlife of ChadReferences edit Lac Tchad Ramsar Sites Information Service Archived from the original on 23 June 2018 Retrieved 25 April 2018 Partie tchadienne du lac Tchad Ramsar Sites Information Service Archived from the original on 23 June 2018 Retrieved 25 April 2018 Lake Chad Wetlands in Nigeria Ramsar Sites Information Service Archived from the original on 23 June 2018 Retrieved 25 April 2018 Partie Camerounaise du Lac Tchad Ramsar Sites Information Service Archived from the original on 1 February 2020 Retrieved 25 April 2018 a b c d e f g h i j k l Gritzner J A Lake Chad Encyclopedia Britannica Chicago Encyclopaedia Britannica Inc Archived from the original on 22 July 2019 Retrieved 13 June 2023 a b c d e Hughes R H Hughes J S 1992 A Directory of African Wetlands PDF IUCN UNEP WCMC pp 329 330 ISBN 2 88032 949 3 Archived PDF from the original on 24 September 2012 Retrieved 14 June 2023 a b c d Wen Yunzhao Lake Chad Encyclopedia of China in Chinese China 03 ed Beijing Encyclopedia of China Publishing House Archived from the original on 13 June 2023 Retrieved 11 June 2023 Obaje Nuhu George 12 August 2009 Geology and Mineral Resources of Nigeria Springer p 69 ISBN 978 3 540 92684 9 Retrieved 6 May 2013 Wright J B 30 November 1985 Geology and Mineral Resources of West Africa Springer p 95 ISBN 978 0 04 556001 1 Retrieved 6 May 2013 Leblanc M Favreau G Maley J Nazoumou Y Leduc C Stagnitti F van Oevelen P J Delclaux F Lemoalle J 2006 Reconstruction of Megalake Chad using Shuttle Radar Topographic Mission data Palaeogeography Palaeoclimatology Palaeoecology 239 1 2 16 27 doi 10 1016 j palaeo 2006 01 003 Archived from the original on 13 June 2023 Retrieved 13 June 2023 Mathieu Schuster Claude Roquin Philippe Duringer Michel Brunet Matthieu Caugy Michel Fontugne Hassan Taisso Mackaye Patrick Vignaud Jean Francois Ghienne 2005 Holocene Lake Mega Chad palaeoshorelines from space Quaternary Science Reviews 24 16 17 1821 1827 doi 10 1016 j quascirev 2005 02 001 Kevin Shillington History of Africa Macmillan Education UK pp 19 31 ISBN 9781137524812 Ogundiran Akinwumi 2005 Four Millennia of Cultural History in Nigeria ca 2000 B C A D 1900 Archaeological Perspectives Journal of World Prehistory 19 138 doi 10 1007 s10963 006 9003 y Marlies Klee Barbara Zach 1999 The Exploitation of Wild and Domesticated Food Plants at Settlement Mounds in North East Nigeria 1800 cal BC to Today The Exploitation of Plant Resources in Ancient Africa 81 88 doi 10 1007 978 1 4757 6730 8 8 a b Decorse Christopher R 2001 West Africa During the Atlantic Slave Trade Archaeological Perspectives Continuum International Publishing Group p 103 ISBN 978 0 7185 0247 8 Retrieved 6 May 2013 Johnston H H 1910 Lake Chad Nature 84 2130 244 245 Bibcode 1910Natur 84 244J doi 10 1038 084244a0 ISSN 1476 4687 S2CID 8682184 a b Appiah Kwame Anthony Gates Henry Louis Jr 2010 Encyclopaedia of Africa Oxford University Press p 254 ISBN 978 0 19 533770 9 Retrieved 6 May 2013 Kevin Shillington History of Africa Macmillan Education UK pp 101 103 188 190 249 256 ISBN 9781137524812 Harlow Barbara 2003 Conference of Berlin 1884 1885 Colonialism ABC CLIO p 139 ISBN 978 1 57607 335 3 Retrieved 6 May 2013 a b 熊正坤 张瑾 8 April 2021 乍得湖 从 文明摇篮 到 死亡之心 Lake Chad From Cradle of Civilization to Heart of Death China Water Resources News Archived from the original on 1 January 2024 Retrieved 1 January 2024 about map Lake Chad Basin Commission Retrieved 26 March 2024 黄先雄 夏斌 万志峰 吕宝凤 蔡周荣 2008 乍得湖盆地构造特征与油气成藏规律初探 A preliminary study on the tectonic characteristics and hydrocarbon accumulation law of the Lake Chad Basin 大地构造与成矿学 03 326 331 doi 10 16539 j ddgzyckx 2008 03 013 a b c d 刘甜甜 刘荣高 葛全胜 2013 基于多源遥感数据的非洲乍得湖水面变化监测 Monitoring of water surface change in Lake Chad in Africa based on multi source remote sensing data 地理科学进展 in Chinese China 32 6 906 912 doi 10 11820 dlkxjz 2013 06 007 a b Marie Therese Sarch Charon Birkett June 2000 Fishing and farming at Lake Chad Responses to lake level fluctuations The Geographical Journal 166 2 156 172 JSTOR 823109 Archived from the original on 18 June 2023 Retrieved 18 June 2023 Jacques Lemoalle Jean Claude Bader Marc Leblanc Ahmed Sedick January 2012 Recent changes in Lake Chad Observations simulations and management options 1973 2011 Global and Planetary Change 80 81 247 254 247 254 doi 10 1016 j gloplacha 2011 07 004 a b c d e 袁宣民 2016 乍得湖的环境 安全及其脆弱性 The environment security and vulnerability of Lake Chad 世界科学 in Chinese China 7 21 23 Archived from the original on 21 March 2023 Retrieved 13 June 2023 Richard Ogutu Ohwayo Vianny Natugonza Laban Musinguzi Mark Olokotum Shamim Naigaga 2016 Implications of climate variability and change for African lake ecosystems fisheries productivity and livelihoods Journal of Great Lakes Research 42 03 498 510 doi 10 1016 j jglr 2016 03 004 a b Evans T 1996 The effects of changes in the world hydrological cycle on availability of water resources In Bazzaz F Sombroek W eds Global climate change and agricultural production FAO John Wiley amp Sons ISBN 92 5 103987 9 Archived from the original on 18 June 2023 Leblanc M Favreau G Tweed S 2007 Remote sensing for groundwater modelling in large semiarid areas Lake Chad Basin Africa Hydrogeology Journal 15 97 100 doi 10 1007 s10040 006 0126 0 a b c Lake Chad almost gone United Nations Environment Programme UNEP Archived from the original on 16 December 2008 Retrieved 5 December 2015 Churchill Okonkwo Belay Demoz Ricardo Sakai Charles Ichoku Chigozie Anarado Jimmy Adegoke Angelina Amadou Sanusi Imran Abdullahi Nir Krakauer 15 December 2015 Combined effect of El Nino southern oscillation and Atlantic multidecadal oscillation on Lake Chad level variability Cogent Geoscience 1 1 doi 10 1080 23312041 2015 1117829 Archived from the original on 24 December 2023 Retrieved 24 December 2023 Wengbin Zhu Jiabao Yan Shaofeng Jia 2017 Monitoring Recent Fluctuations of the Southern Pool of Lake Chad Using Multiple Remote Sensing Data Implications for Water Balance Analysis Remote Sensing 9 10 1032 doi 10 3390 rs9101032 Willibroad Gabila Buma Sang Il Lee Jae Young Seo 2018 Recent surface water extent of Lake Chad from multispectral sensors and GRACE Sensors 18 7 2082 doi 10 3390 s18072082 PMC 6069056 PMID 29958481 a b c d Emma Martin Neil Burgess Lake Chad Flooded Savanna www oneearth org Archived from the original on 15 July 2023 Retrieved 15 July 2023 Binh Pham Duc Florence Sylvestre Fabrice Papa Frederic Frappart Camille Bouchez Jean Francois Cretaux 2020 The Lake Chad hydrology under current climate change Scientific Reports 10 5498 doi 10 1038 s41598 020 62417 w PMC 7099084 a b Keith J O Plowes D C H March 1997 Considerations of Wildlife Resources and Land Use in Chad PDF Report Office of Sustainable Development Africa Bureau USAID p 3 SD Technical Paper No 45 Archived from the original PDF on 18 June 2023 Luxereau A Genthon P Ambouta J M K 2011 Fluctuations in the Size of Lake Chad Consequences on the Livelihoods of the Riverain Peoples in Eastern Niger Regional Environmental Change 12 3 507 521 doi 10 1007 s10113 011 0267 0 Archived from the original on 14 June 2023 Retrieved 13 June 2023 Roman D Zarate Remi Jedwab Federico Haslop Carlos Rodriguez Castelan 5 September 2023 The Effects of Climate Change in the Poorest Countries Evidence from the Permanent Shrinking of Lake Chad World Bank Retrieved 8 April 2024 Olowoyeye Oluwatuyi S Kanwar Rameshwar S 2023 Water and Food Sustainability in the Riparian Countries of Lake Chad in Africa Sustainability 15 13 10009 2 doi 10 3390 su151310009 About us Lake Chad Basin Commission Archived from the original on 15 July 2023 Retrieved 15 July 2023 Ross Will 31 March 2018 Can the vanishing lake be saved BBC Archived from the original on 9 August 2019 Retrieved 28 January 2019 Further reading editHughes R H Hughes J S 1992 A Directory of African Wetlands IUCN ISBN 978 2 88032 949 5 Beadle L C 1974 The Inland Waters of Tropical Africa An Introduction to Tropical Limnology Hardcover 1th ed Longman Publishing Group ISBN 978 0582448520 Chapman Graham Baker Kathleen M 1992 The changing geography of Africa and the Middle East Routledge ISBN 9780203034507 Caterina Batello Marzio Marzot Adamou Harouna Toure 2004 The Future is an Ancient Lake FAO Interdepartmental Working Group on Biological Diversity for Food and Agriculture ISBN 92 5 105064 3 External links edit nbsp Wikimedia Commons has media related to Lake Chad category Lake Chad Basin Commission BIOsphere and Heritage of Lake Chad BIOPALT project The Ups and Downs of Lake Chad Lake Chad in worldlakes org Lake Chad in World Lake Database Lake Chad UN News Retrieved from https en wikipedia org w index php title Lake Chad amp oldid 1220425481, wikipedia, wiki, book, books, library,

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