Lake Débo
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Lake Débo is a
lake A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from ...
in the central part of
Mali Mali, officially the Republic of Mali, is a landlocked country in West Africa. It is the List of African countries by area, eighth-largest country in Africa, with an area of over . The country is bordered to the north by Algeria, to the east b ...
, formed by the seasonal flooding of the
Niger River The Niger River ( ; ) is the main river of West Africa, extending about . Its drainage basin is in area. Its source is in the Guinea Highlands in south-eastern Guinea near the Sierra Leone border. It runs in a crescent shape through Mali, Nige ...
basin. It is in the
Inner Niger Delta The Inner Niger Delta, also known as the Macina or Masina, is the inland river delta of the Niger River. It is an area of fluvial wetlands, lakes and floodplains in the semi-arid Sahel area of central Mali, just south of the Sahara Desert. ...
of the
Niger River The Niger River ( ; ) is the main river of West Africa, extending about . Its drainage basin is in area. Its source is in the Guinea Highlands in south-eastern Guinea near the Sierra Leone border. It runs in a crescent shape through Mali, Nige ...
. During high water stages of the river, the delta formed by lakes, creeks, and backwaters form part of Lake Débo. The inner delta has many wide channels, which are shallow and flooded marshes; this delta extends over a length of with a width of . Lake Débo during high flow season, is at a distance of from Mopti on its upstream, on the southern end and from
Timbuktu Timbuktu ( ; ; Koyra Chiini: ; ) is an ancient city in Mali, situated north of the Niger River. It is the capital of the Tombouctou Region, one of the eight administrative regions of Mali, having a population of 32,460 in the 2018 census. ...
at its downstream, on the north-eastern end. It is the largest of many such seasonal wetlands and lakes which form the
Inner Niger Delta The Inner Niger Delta, also known as the Macina or Masina, is the inland river delta of the Niger River. It is an area of fluvial wetlands, lakes and floodplains in the semi-arid Sahel area of central Mali, just south of the Sahara Desert. ...
, and the largest lake within Mali. Its size is largely reduced during the dry season of September to March. The existence of this lake called the "Great Lake" in the inner delta of
Niger River The Niger River ( ; ) is the main river of West Africa, extending about . Its drainage basin is in area. Its source is in the Guinea Highlands in south-eastern Guinea near the Sierra Leone border. It runs in a crescent shape through Mali, Nige ...
between Jenne and
Timbuktu Timbuktu ( ; ; Koyra Chiini: ; ) is an ancient city in Mali, situated north of the Niger River. It is the capital of the Tombouctou Region, one of the eight administrative regions of Mali, having a population of 32,460 in the 2018 census. ...
in Mali has been established after extensive study of maps of the region extending over a period from 1000 to 1900 AD; 400 maps were studied for the period.


History

This lake, called the "Great Lake" in the inner delta of
Niger River The Niger River ( ; ) is the main river of West Africa, extending about . Its drainage basin is in area. Its source is in the Guinea Highlands in south-eastern Guinea near the Sierra Leone border. It runs in a crescent shape through Mali, Nige ...
between Jenne and
Timbuktu Timbuktu ( ; ; Koyra Chiini: ; ) is an ancient city in Mali, situated north of the Niger River. It is the capital of the Tombouctou Region, one of the eight administrative regions of Mali, having a population of 32,460 in the 2018 census. ...
in Mali, was known to Europeans from very early times. The earliest known report of it was in the first millennium BC.
Ptolemy Claudius Ptolemy (; , ; ; – 160s/170s AD) was a Greco-Roman mathematician, astronomer, astrologer, geographer, and music theorist who wrote about a dozen scientific treatises, three of which were important to later Byzantine science, Byzant ...
described it as having the shape of a
barbell A barbell is a piece of exercise equipment used in weight training, bodybuilding, Olympic weightlifting, weightlifting, powerlifting and strongman, consisting of a long bar, usually with weights attached at each end. Barbells range in length ...
. Study of more than 400 maps of the region created over a period from 1000 to 1900 AD found that the lake appeared on 95 percent; the only feature depicted on more maps was the
Nile The Nile (also known as the Nile River or River Nile) is a major north-flowing river in northeastern Africa. It flows into the Mediterranean Sea. The Nile is the longest river in Africa. It has historically been considered the List of river sy ...
. The lake has been known variously as Nigrite Palus, Lake Sigisma, Lake Guber, Lake Guarda, Bog/Morais of Guarda, Lake Maberia, Bahar Seafeena, Lake Dibbie, but it is now known as Lake Débo. The Niger River is assessed as a young river of 2000 years age and is yet to stabilize. However, the natural channels have undergone many meandering changes.


Geography

The lake is formed upstream of the confluence of Niger and
Bani River The Bani River is the principal tributary of the Niger River in Mali. The river is formed from the confluence of the Baoulé and Bagoé rivers some east of Bamako and it merges with the Niger near Mopti. Its length is about . Geography The ...
s. It is the best known
lacustrine A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from t ...
lake in Mali, which has diameter of and shallow and hence large vessels can not pass through the lake. In the upper highland reaches of these rivers, the highland terrain slopes are very gentle resulting in the retardation of flows and creation of this lake. The slope reported before the creation of the lake is per . The lake is divided by a barrier into two zones, the upper and the lower. The barrier extends several kilometres southwards. Beyond the barrier, the lake is narrow and long and its outreach is not visible. The Bara Lisa River joins the Niger above
Dire Dire may refer to: Places * Diré, a town in Tombouctou Region, Mali * Diré Cercle, an administrative subdivision of Tombouctou Region, Mali * Dire (Aanaa), a woreda in Oromia Region, Ethiopia People * Dire Tladi (born 1975), South African law p ...
. It exits the deltas from the northern shores of Lake Debo and flows east. The Issa Baris, the main arm of the lake, exits from the lake in a westerly direction and turns northeast to join the Bara Lisa. Geological formations recorded at the bed of the lake are "from dense
crystalline rock A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macrosco ...
of
Precambrian The Precambrian ( ; or pre-Cambrian, sometimes abbreviated pC, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of t ...
sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...
compacted in the broad Taoudeni
Syncline In structural geology, a syncline is a fold with younger layers closer to the center of the structure, whereas an anticline is the inverse of a syncline. A synclinorium (plural synclinoriums or synclinoria) is a large syncline with superimposed ...
as an
alluvial fan An alluvial fan is an accumulation of sediments that fans outwards from a concentrated source of sediments, such as a narrow canyon emerging from an escarpment. They are characteristic of mountainous terrain in arid to Semi-arid climate, semiar ...
and covered by a hard layer of cemented-
laterite Laterite is a soil type rich in iron and aluminium and is commonly considered to have formed in hot and wet tropical areas. Nearly all laterites are of rusty-red coloration, because of high iron oxide content. They develop by intensive and prolo ...
." The flat slopes and geology of the beds has resulted in creating a meandering and multi-channel flow pattern, which has resulted in the formation of inner delta of the Niger. The inner delta thus has many wide channels, which are shallow and flooded marshes; this delta extends over a length of with a width of . It is inferred from the study of nearly 400 maps that it is the delta which is the origin of the lake and that the lake is the largest in the delta. It is integral to the wide river channel with its size fluctuating with variation of the water level in the lake. It also provides confirmation of the nature of blocked water and also includes the
Erg of Bara The erg is a unit of energy equal to 10−7joules (100 nJ). It is not an SI unit, instead originating from the centimetre–gram–second system of units (CGS). Its name is derived from (), a Greek word meaning 'work' or 'task'. An erg is the ...
region. The maximum flood in the lake and the delta occurs during November and December. Below Lake Debo, the Niger valley is marked by a large number of lakes, which are lower than the river level. As part of the central delta, the lake is the largest. As it is a part of the Niger River, its size varies with the fluctuation in the water level. and maximum flood occurs in the river during November and December. The lake has a vast expanse of water extending on all sides. The river that is formed at the outlet of the lake has a width of for a length of downstream, where after it narrows down, gets spilled into many channels; marshy islands are formed and depth of water is in the range of . Foolahs, the
nomads Nomads are communities without fixed habitation who regularly move to and from areas. Such groups include hunter-gatherers, Nomadic pastoralism, pastoral nomads (owning livestock), tinkers and Merchant, trader nomads. In the twentieth century, ...
who live here, use these marshes as pastures in the dry season and thereafter they go back to their habitats in the interior of the basin. During the high flood stage, flood waters arriving at the lake are reported as . This was absorbed in the vast lake, as storage, and the out flow from the lake is thus moderated to only when it reaches
Niamey Niamey () is the capital and largest city of Niger. As the Niamey Urban Community (, CUN), it is a Regions of Niger, first-level division of Niger, surrounded by the Tillabéri Region, in the western part of the country. Niamey lies on the Nige ...
, the capital city of Niger. Since 1962, even a extra flow from the lake could now cause increase of water level in the Niamey area by , rising to the level .


Climate

The lake in the
Sahel The Sahel region (; ), or Sahelian acacia savanna, is a Biogeography, biogeographical region in Africa. It is the Ecotone, transition zone between the more humid Sudanian savannas to its south and the drier Sahara to the north. The Sahel has a ...
, just south of the Sahara desert, has climatic conditions which are reported to be a transitional zone of humid Guinean climate in the south to a dry climate at border with the Sahara. The rainy season in the south lasts from July to October, with an average annual rainfall of . However, the rainy season in the north lasts from July to September, with an average annual precipitation recorded at . Temperatures vary with strong seasonal emphasis. The average maximum temperature recorded in May at Tombouctou is and at
Mopti Mopti (Fulfulde: Mobti) is a town and an urban commune in the Inner Niger Delta region of Mali. The town is the capital of the Mopti Cercle and the Mopti Region. Situated 630 km northeast of Bamako, the town lies at the confluence of the ...
is . The cooler climatic season is from December to January with temperatures dropping to a mean minimum of to in the northern part of the delta. Lake Débo during high flow season when it has the maximum dimensions of water spread, is from Mopti on its upstream, on the southern end, and from
Timbuktu Timbuktu ( ; ; Koyra Chiini: ; ) is an ancient city in Mali, situated north of the Niger River. It is the capital of the Tombouctou Region, one of the eight administrative regions of Mali, having a population of 32,460 in the 2018 census. ...
at its downstream, on the north-eastern end. It is the largest of many such seasonal wetlands and lakes which form the
Inner Niger Delta The Inner Niger Delta, also known as the Macina or Masina, is the inland river delta of the Niger River. It is an area of fluvial wetlands, lakes and floodplains in the semi-arid Sahel area of central Mali, just south of the Sahara Desert. ...
, and the largest lake within Mali. Its size is largely reduced during the dry season of September to March.


Vegetation

The inundated Lake Débo and Walado Débo (Inner Niger Delta in Mali) form the pasture lands which are collectively known as the flooded forest savannah with aquatic herbaceous and two dominant species of
acacia ''Acacia'', commonly known as wattles or acacias, is a genus of about of shrubs and trees in the subfamily Mimosoideae of the pea family Fabaceae. Initially, it comprised a group of plant species native to Africa, South America, and Austral ...
. These pastures are known locally as '' bourgou'' grass. Palms like ''
Hyphaene thebaica ''Hyphaene'' is a genus of palms native to Africa, Madagascar, the Middle East, and the Indian subcontinent The Indian subcontinent is a physiographic region of Asia below the Himalayas which projects into the Indian Ocean between the Bay ...
'', and ''
Borassus aethiopum ''Borassus aethiopum'' is a species of '' Borassus'' palm from Africa. In English, it is variously referred to as African fan palm, African palmyra palm, deleb palm, ron palm, toddy palm, black rhun palm, rônier palm (from the French). It is wid ...
'' are also reported on the fringes of the lake. There are three types of pasture lands, defined on the basis of its management. These are: Resident Fulani's pastures which are controlled by the Amiro (the chief Joro); the "Harima" (meaning: a local convention) with the chief of village and other members responsible for its usage; and the several small holdings (within the ''bourgou'') parceled to private individuals. the perennial grasses grown are edible and easily digestible with botanical names of ''
Echinochloa stagnina ''Echinochloa stagnina'' (Burgu millet, bourgou, hippo grass) is a species of '' Echinochloa'' widespread in tropical Africa and Asia, with an invasive status in many Pacific islands. It was once one of the major grasses cultivated in the Inner ...
'' (a perennial plant) and '' Vossia cuspidata'', and which grow in varying depths of water (). The crop variety, which is extensive, is of
wild rice Wild rice, also called manoomin, mnomen, psíŋ, Canada rice, Indian rice, or water oats, is any of four species of grasses that form the genus ''Zizania'', and the grain that can be harvested from them. The grain was historically and is sti ...
(
Oryza longistaminata ''Oryza longistaminata'' is a perennial species of grass from the same genus as cultivated rice (''O. sativa''). It is native to most of sub-Saharan Africa and Madagascar. It has been introduced into the United States, where it is often regarded ...
and bartti). Another plant species that acts as barrier to sand deposition is the '' Vetiveria nigritiana,'' when the water stages in the lake and the delta is high. The aquatic plants sustain varying levels of water in the lake and the soil types dictates the
ecology Ecology () is the natural science of the relationships among living organisms and their Natural environment, environment. Ecology considers organisms at the individual, population, community (ecology), community, ecosystem, and biosphere lev ...
of the region. The sloping banks of the lake have shrubs interspersed with grasses and vacant patches, and woody species, generally of acacia species. Akkagoun and Dentaka are the forested areas surrounding the lake and the delta, which are home for many water birds.
Algal bloom An algal bloom or algae bloom is a rapid increase or accumulation in the population of algae in fresh water or marine water systems. It is often recognized by the discoloration in the water from the algae's pigments. The term ''algae'' encompass ...
s are also reported from the lake which could result in reduction of the water transparency.


Fauna

The
West African manatee The African manatee (''Trichechus senegalensis''), also known as the West African manatee, is a species of manatee that inhabits much of Western Africa – from Senegal to Angola. It is the only manatee species to be found in the Old World. Ta ...
is the most prominent fauna species in the lake which is reported as its last habitat in the world.
Hippo The hippopotamus (''Hippopotamus amphibius;'' ; : hippopotamuses), often shortened to hippo (: hippos), further qualified as the common hippopotamus, Nile hippopotamus and river hippopotamus, is a large semiaquatic Mammal, mammal native to su ...
s are also reported from the lake (the hippo population is estimated at 40 to 60 individuals).
Nile crocodile The Nile crocodile (''Crocodylus niloticus'') is a large crocodilian native to freshwater habitats in Africa, where it is present in 26 countries. It is widely distributed in sub-Saharan Africa, occurring mostly in the eastern, southern, and ce ...
is also reported from the flood plains. Within the basin area of the lake and the delta mammal species reported include: roan antelope,
dorcas gazelle The dorcas gazelle (''Gazella dorcas''), also known as the ariel gazelle, is a small and common gazelle. The dorcas gazelle stands about at the shoulder, with a head and body length of and a weight of . The numerous subspecies survive on veget ...
,
dama gazelle The dama gazelle (''Nanger dama''), also known as the addra gazelle or mhorr gazelle, is a species of gazelle. It lives in Africa, in the Sahara desert and the Sahel. A critically endangered species, it has disappeared from most of its former ra ...
,
red-fronted gazelle The red-fronted gazelle (''Eudorcas rufifrons'') is widely but unevenly distributed gazelle across the middle of Africa from Senegal to northeastern Ethiopia. It is mainly resident in the Sahel zone, a narrow cross-Africa band south of the Sahar ...
, whilst reptile species include
Nile monitor The Nile monitor (''Varanus niloticus'') is a large member of the monitor family (Varanidae) found throughout most of Sub-Saharan Africa, particularly in drier regions, and along the Nile River and its tributaries in East Africa. Additionally, th ...
and
African rock python The Central African rock python (''Python sebae'') is a species of large constrictor snake in the family Pythonidae. The species is native to sub-Saharan Africa. It is one of 10 living species in the genus ''Python''. Africa's largest snake and ...
. The
avifauna Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight ...
found within the lake area, which forms one of the major wetlands in the
Sahel The Sahel region (; ), or Sahelian acacia savanna, is a Biogeography, biogeographical region in Africa. It is the Ecotone, transition zone between the more humid Sudanian savannas to its south and the drier Sahara to the north. The Sahel has a ...
, is represented by species from both the
Palearctic The Palearctic or Palaearctic is a biogeographic realm of the Earth, the largest of eight. Confined almost entirely to the Eastern Hemisphere, it stretches across Europe and Asia, north of the foothills of the Himalayas, and North Africa. Th ...
and
Afrotropic The Afrotropical realm is one of the Earth's eight biogeographic realms. It includes Sub-Saharan Africa, the southern Arabian Peninsula, the island of Madagascar, and the islands of the western Indian Ocean. It was formerly known as the Ethiopi ...
ecozones. Over one million birds have been recorded as using the lake;, including a large number of migratory and resident species, such as
sand martin The sand martin (''Riparia riparia''), also known as collared sand martin or common sand martin, and in the Americas as the bank swallow, is a migratory passerine bird in the swallow family Hirundinidae. It has a wide range in summer, embracing ...
and yellow wagtail,
reed cormorant The reed cormorant (''Microcarbo africanus''), also known as the long-tailed cormorant, is a bird in the cormorant family Phalacrocoracidae. It breeds in much of Africa south of the Sahara, and Madagascar. It is resident but undertakes some seas ...
,
glossy ibis The glossy ibis (''Plegadis falcinellus'') is a water bird in the order Pelecaniformes and the ibis and spoonbill family Threskiornithidae. The scientific name derives from Ancient Greek ''plegados'' and Latin, ''falcis'', both meaning "sickle" a ...
,
spoonbill Spoonbills are a genus, ''Platalea'', of large, long-legged wading birds. The spoonbills have a global distribution, being found on every continent except Antarctica. The genus name ''Platalea'' derives from Ancient Greek and means "broad", refe ...
,
great white egret The great egret (''Ardea alba''), also known as the common egret, large egret, great white egret, or great white heron, is a large, widely distributed egret. The four subspecies are found in Asia, Africa, the Americas, and southern Europe. R ...
,
purple heron The purple heron (''Ardea purpurea'') is a wide-ranging heron species. It breeds in Africa, central and southern Europe, and southern and eastern Palearctic. The Western Palearctic populations migrate between breeding and wintering habitats whe ...
,
ferruginous duck The ferruginous duck (''Aythya nyroca''), also known as ferruginous pochard, common white-eye or white-eyed pochard, is a medium-sized diving duck from Eurosiberia. The scientific name is derived from the Ancient Greek word, (), an unknown se ...
,
white-winged black tern The white-winged tern, or white-winged black tern (''Chlidonias leucopterus'' or ''Chlidonias leucoptera''), is a species of tern in the family Laridae. It is a small species generally found in or near bodies of fresh water across much of the wo ...
,
ruff Ruff may refer to: Places *Ruff, Virginia, United States, an unincorporated community *Ruff, Washington, United States, an unincorporated community Other uses *Ruff (bird) (''Calidris pugnax'' or ''Philomachus pugnax''), a bird in the wader famil ...
and
black-tailed godwit The black-tailed godwit (''Limosa limosa'') is a large, long-legged, long-billed shorebird first described by Carl Linnaeus in 1758. It is a member of the godwit genus, '' Limosa''. There are four subspecies, all with orange head, neck and ches ...
. However, a number of Afrotropical species such as the rare
black crowned crane The black crowned crane (''Balearica pavonina'') is a part of the family Gruidae, along with its sister species, the grey crowned crane. It is topped with its characteristic bristle-feathered golden crown. It is usually found in the shallow we ...
are dwindling. A sea side feeling is felt around the lake and the delta, as the air is filled with the sounds of water birds and
gull Gulls, or colloquially seagulls, are seabirds of the subfamily Larinae. They are most closely related to terns and skimmers, distantly related to auks, and even more distantly related to waders. Until the 21st century, most gulls were placed ...
s. As the lake is an important stopping place for
migratory birds Bird migration is a seasonal movement of birds between breeding and wintering grounds that occurs twice a year. It is typically from north to south or from south to north. Migration is inherently risky, due to predation and mortality. The ...
,
UNESCO The United Nations Educational, Scientific and Cultural Organization (UNESCO ) is a List of specialized agencies of the United Nations, specialized agency of the United Nations (UN) with the aim of promoting world peace and International secur ...
has classified it as a Ramsar zone under the title whole of Lake Walado Débo, which is part of the inner delta with 350 species of birds, including 118 migratory species. The '' Synodontis gobroni'' and the ''
Gobiocichla ''Gobiocichla'' is a small genus of rheophilic cichlids native to the Cross ( Manyu) and Niger Rivers in Africa. Species There are currently two recognized species in this genus: * '' Gobiocichla ethelwynnae'' T. R. Roberts, 1982 * '' Gobiocich ...
wonderi'' are two endemic species of fishes in the lake which is part of the inland delta. The aquatic fauna in the delta as a whole, which is reflective of the lake also, consists of 130 species mostly of the species in the families of
Mormyridae The Mormyridae, sometimes called "elephantfish" (more properly freshwater elephantfish), are a superfamily of weakly electric fish in the order Osteoglossiformes native to Africa. It is by far the largest family in the order, with around 200 sp ...
,
Mochokidae The Mochokidae are a family of catfishes (order Siluriformes) that are known as the squeakers or known as upside-down catfish (although not all species swim upside-down). There are nine genera and about 200 species of mochokids. All the mochokid ...
, and
Cyprinidae Cyprinidae is a family of freshwater fish commonly called the carp or minnow family, including the carps, the true minnows, and their relatives the barbs and barbels, among others. Cyprinidae is the largest and most diverse fish family, and t ...
. There are many migratory fish species which migrate along the river to this region; out of these migrating fishes the
African tetras African tetras (family Alestidae, formerly spelled Alestiidae) are a group of characiform fish found exclusively in Africa. This family contains about 18 genera and 119 species. Among the best known members are the Congo tetra, and African tiger ...
''
Brycinus ''Brycinus'' is a genus of ray-finned fish in the family (biology), family Alestiidae, the African tetras. Like other "African characids", they were formerly included in the Characidae but are actually somewhat more distantly related Characiforme ...
leuciscus'' travels long distances up to the delta and also up to the toe of the Markala Dam.


Culture

When the
Niger Niger, officially the Republic of the Niger, is a landlocked country in West Africa. It is a unitary state Geography of Niger#Political geography, bordered by Libya to the Libya–Niger border, north-east, Chad to the Chad–Niger border, east ...
and
Bani River The Bani River is the principal tributary of the Niger River in Mali. The river is formed from the confluence of the Baoulé and Bagoé rivers some east of Bamako and it merges with the Niger near Mopti. Its length is about . Geography The ...
s are in spate, fishing operations are carried out in the lake using trawlers. The ethnic Bozo fisherman, resident on the shores of the lake are involved in these operations. During the dry season, the many ethnic
Fula Fula may refer to: *Fula people (or Fulani, Fulɓe) *Fula language (or Pulaar, Fulfulde, Fulani) **The Fula variety known as the Pulaar language **The Fula variety known as the Pular language **The Fula variety known as Maasina Fulfulde *Fula alpha ...
nomads come to this lake area as their terminus destination during the seasonal
transhumance Transhumance is a type of pastoralism or Nomad, nomadism, a seasonal movement of livestock between fixed summer and winter pastures. In montane regions (''vertical transhumance''), it implies movement between higher pastures in summer and low ...
migration along with their herds from the north.


References

{{DEFAULTSORT:Lake Debo Debo Debo Niger River