Environmental Issues in the Lake Chad Basin by Baba Ali Mustapha.
For much of my research work that follows I was deeply indebted to Professor Haruna .K. Ayuba, and Dr. A. Dami both of University of Maiduguri Department of Geography.
Background:-
The Lake Chad is located approximately between latitude, 120N and 140, 300N and longitudes 130E and 150, 300E. The Lake Chad basin originated as a result of peripheral uplift outside the basins which led to the formation of a closed inland drawage basin, with a large lake almost at the centre (Burke, 1979). Other Scholars (Sike, 1972: Carmouze and Lamoalle, 1983: Servant and Servant 1983: Grove 1958; Thambyapilly 1983:Kolawale, 1983, 1993: Dami 2008) have contributed greatly to our present knowledge of the lake.
The history of the lake is replete with periods of complete drying up followed by periods of surging back of the lake waters, Carmouze and Lamoalle, 1983 as well as Servant and Servant (1983) examined the lake sediments to throw light on the historical evolution of the lake. According to them analysis of diatomaceous materials in the sediments enable scientists to reconstruct the hydrological history of the lake. The first change in the basin, which occurred between 12, 000 and 22, 000 years ago led to the complete drying up of the lake and subsequent formation of sand dune ridges as a result of wind erosion and deposition. Climate change later led to wet conditions around 6000 years ago and resulted in the lake surging back. The lake which extended to Bama beach ridge (BBR) is referred to as Mega Chad. The Mega Chad level stood at 320 meters above sea level (asl) and the lake covered an area of 1.5 million Km2. Later, there were complex fluctuations accompanied by alternating wet and dry phase. Each phase affected the level and area covered by the lake.
The reduction of the lake to around 284 meters asl was achieved about 2500 years ago and had fluctuated around this level.
Actual measurement of the lake was started in 1911 by the French colonial masters. They recognized three levels of the lake fluctuation in recent times namely: Greater Chad, Normal or standard Chad and Lesser Chad (Sike, 1972). Greater Chad condition is when the lake level is at 283m as/or more and the area of the lake is around 25, 000km2. Normal Chad condition is when lake level is around 282m as land area of the lake is about 20,000 km2. Lesser Chad condition is when the lake level is below 280m asl, this was experienced in 1905-8, 1910 – 1916, 1972 -5 and 1983 to date.
Kolawale (1988) examined recent ecological changes associated with the present shrinking of the lake and came up with the concept of the lake floor which is the area of the lake that has become dry ground between 1962/63 and 1984. According to how the emerging dry ground is used for cultivation, grazing and settlement. The drought of the mid 1980s lowered the lake level to mere 276m asl and the area of the lake reduced to 3000km2 (Kolawale, 1993). Study by Odada et al (2004) put the area of the lake floor to be around 1350km2.
The volume, depth and area of the lake water are controlled by the lake morphology and the input-output regime of water in the lake (Carmoze and Lamoalle, 1983; Sike 1972). The input which comes from is affluence is a product of rainfall within the basin. The Chari-Lagone system accounts roughly for 90% of the lake’s inflow while the Yobe, Yedseram, Ebeji and local runoff account for the remainder (Sikes 1972, Odada et al, 2004). The output is mainly through evaporation and filtration into the soil. Therefore, the lake’s viability depends on regular and normal inflow from its affluent. Any deficit in the inflow is bound to affect the lake adversely. The south Chad irrigation Project (SCIP) and Baga Polder Project (BPP) were based on normal Chad condition. The abstraction of lake water for irrigation become stranded and collapsed because of the reduction of lake to lesser Chad condition and the emergence of rest areas the lake floor. The lake floor increased rapidly because the morphology of the lake is such that even slight fall of the lake level of only 0.5 meters is capable of reducing the area of the lake considerable (Sike, 1972; Carmouze and Lamoalle, 1983 and Servant and Servant, 1983).
Physical setting.
i. Hydrogeology :-
Hydro-geologically, the basin lies in a tectonic zone with an extensive sedimentary basin where depositional event, resetting the formation of four aquifers, had taken place in tertiary and quaternary times (LCBC, 2007). The four aquifers, which are some what modified to only three on the Nigerian sector, are; a. The phreatic aquifer of quaternary age; it is the most exploited and the most affected by climatic fluctuations; b. The perched or artesian aquifer at great depths; c. The lower Pliocene aquifer consisting of 20-70 thick of sand deposits, 300m deep on the average, separated by 100-200m thick of clay and d. The continental terminal aquifer, consisting of 40 – 60m of sand deposits about 6000m average depth, is being increasingly exploited in Nigeria particularly since the 1970s.
The Chari River, fed by its tributary the Logone provide over 90 percent of Lake Chad’s water, with a small amount coming from Yobe river in Nigeria. In spite of high levels of evaporation in the basin the lake is still a freshwater. Over half of the lake’s area it taken up by its many small Islands. Reedbeds and mud banks, whole the shorelines are largely composed of marshes. Because Lake Chad is very shallow only 10.5 meters (344ft) at its deepest- its area is particular sensitive’s to small change in average depth, and consequently it also show seasonal fluctuation in size of about 1m every year. Lake Chad has no apparent outlet, but its waters percolate into the Soro and Bodele depressions.
ii. Climate:-
The lake basin comprise of five bioclimatic zones, namely: Sahara, Sahelo-shara, sahelo-Sudanian, Sudano-Sahelian and sudana-guinea ecological zones. The south-west humid atlantic (monsoon) and the north-east hot and dry (harmattan) currents influence the climate and consequently the ecological zonation of the basin. During the winter months the cool, dry, dust-laden “harmattan” blows from the Sahara in the north, bringing low humidity, cool night and warm days. In summer months, moisture-laden winds blows from the golf of guinea in the south bringing high humidity rains and more uniform diurnal temperature. The monsoon advances from the south, so that rain start earlier, are heavier and last longer in the south wards, although in general there is high spatial and temporal variability over the entire area.
iii. Soil and Vegetation
The soil characteristic of the Chad basin region are ferruginous tropical and undifferentiated semi-arid brown soils. They cover about two-fifths of the basin while the remaining 60 percent is covered by zonal verticals, regosols and mixtures of alluvial and vertisols characterized by a high shrink-swell potential. Agboola, (1979) rated about 90 percent of the Nigerian sector of the basin as having soil potentiality of medium to high fertility. A number of major vegetation type could be described in the basin. One is wood land made up of species from the edge of the Sudan-Guinea and sahelo-sudanian zone intruding into the south of Chad. This is the wetter part receiving most of the rain and heavily a sub-humid tropical climate. The woodland vegetation gradually turns into pseudo-steppe towards the 500 millimeters 150hyets, first with andropogonae (For example Acacia Scorpiodes Var ,adstringens, , acacia Siberian, A. seyal, A. ataxacantha, A coffra Var, Compylacanth, A. Senegal, etc) and then with arisideae. The shift is marked by the occurrence of different species of tree and shrubs (example of tree species are anogeissus leiovarpus and siletrocarya birrea further north, towards 100 to 200 millimeters isohyets, the grassy carpet steadily thin out, leaving tufts with their roots often lay bare by the wind and the remaining species become fewer (Sarch and Birkeff, 2000).
Socio-Economic Characteristics.
i. Population:-
The basin carries at present a human population of approximately 20 million people with a growth rate of about 2.7 percent per year. It support, in addition, an estimated total livestock population of about 18 million unit (including cattle, goats and sheep, camel and donkeys). Adeniji (1983) estimated the livestock carrying capacity of the basin on the Nigerian side to be about 3.3 ha per unit. The carrying capacity of the entire basin may be in the neighborhood of 3.5 – 4.0 ha per unit.
ii. Economic activities.
According to the African Development Bank (ADB) report of 2006, the member countries within the basin (namely Nigeria, Cameroon, Chad, Niger, Central African Republic and Sudan) are characterized by poverty, poor health and low educational status, which reflect in the high mortality rate in the various countries. The following can be said about the six countries:
a. They were are still among the last forty on the human development index classification;
b. Household parching power in these countries has continued to decline while those of the other development countries keep increasing on the average. This keeps increasing on the average. This means that poverty is widespread and steadily on the increase while prospects for economic growth are reducing.
c. Measured calories, food consumption per person have been declining considerably, indicating that malnutrition is widespread. Food production appears to be on the increase in some of those countries, but taking into account land areas of those countries, the production in Nigeria, Cameroon and CAR but they could be from the other areas outside the basin.
iii. The Lake Chad Basin Commission (LCBC).
The Lake Chad Basin commissions (LCBC), as an inter governmental agency, was established by the fort Lamy (N’Djamena) convention and status of may 22nd, 1964, by the head of four countries notable, Cameroon, Chad, Niger and Nigeria. The Central African Republic was admitted as the fifth member of the basin on the 28th July 2000. The admission of Sudan increased the conventional area of the 1, 035, 000km2 in 2000.
According to LCBC conservation and statues, the primary responsibility of the commission are to regulate and control the utilization of water and other natural resources in the basin, initiate, promote and coordinate natural resources development projects and research within the basin area; examine complaints; and promote the settlement of disputes, thereby prompting regional co-operation. In December 1977, the LCBC signed a protocol for harmonization of regulations relating to the fauna and flora in the four member states, and adopted plan for the multi-donor approach towards major integrated development for the conventional basin. In 1994, member state approved a master plan for the development and environmentally sound management of the natural resources of the conventional basin. A strategic action plan with long-term vision (20years) for the basin that was prepared by the global environmental facility (GEF) was adopted by the member states in 1998. In March 1999, a 3year Inland fisheries project financed by the European Union started in the Lake Chad (Giwa, 2002). The fort Lamy convention recognizes the sovereign right of the member state over the water resources in the basin, but forbids any unilatered exploitation of the lake water, especially when such use has potentially negative effect on the interests of the other states. It also recognizes the other member state to plan prefects, provided that they consult the LCBC before hand. However, the member state are supposed to refrain from adopting any measures likely to alter the lake’s water balance, its exploitation by other rip balance, its exploitation by the other riparian states, the quality of its water and the biological characteristics of the fauna and flora in the basin. The member state must inform the LCBC of all project planned within the “conventional” basin.
Main Environmental Issues in the Lake Chad Basin
(i) The receding lake (from Greater/Mega Chad - Normal Chad – to lesser Chad).
The Lake Chad Basin serves as a source of freshwater to over 20 million people who depend on it for their livelihood. The Lake within it’s rich biodiversity also provide a source of fishery, pastoral and agricultural activities for the inhabitants in the Basin. However, the Lake has continued to shrink owing to natural and anthropogenic forces. It is estimated that surface area of the Lake has shrunk from 25, 000km2 to less than 3000km2 today. The lake has gone through many phases of change from the Mega – Chad, Normal Chad to the lesser Chad.
The greater (Mega Chad Lake) covered an area of about 25, 000km2 and looked more like a small Island sea level with a surface level of 283m above sea level. Navigation in the Lake was much easier. Flooding of border village was one of the major hazards when the Lake was under Greater Chad condition.
NORMAL CHAD
The area of the lake under normal Chad was around 21, 000km2 (Sikes 1972; Carmouze, et.al 1983). Water level under this condition was about 281.9m above sea level. This condition occurred in 1909-13, 1919-20 and 1964-71, under Normal Chad condition, the input-output ratio was more or less in a balance. Flooding and recession of the lake was minimal.
LESSER CHAD
Lesser Chad condition occurred in 1905-8, 1910, 1916, 1972-5 and 1983 to date (Sikes, 1972; Carmouze, et.al 1983, Kolawale 1983). The lake reduced from 9, 000km2 during the 1972-5 sahel drought (Carmouze, et.al 1983) to about 3, 000km2 by 1986 (Kolawole, 1993). The lake level fell below 280m above sea level. This rapid regression of the lake has been of great concern because of it’s multiplier effect. Aquatic life as well as social and economic activities, which depend on these natural resources and adversely affected.
The reduction in the site of the lake is associated with two main factors: climate and anthropogenesis. The climatic factors relate chiefly to the declining frequency and volume of rainfall received within and outside the basin which have affected the amount of water directly available from the rainfall as well as that coming from rivers that drawn into the basin. The anthropogenetic factors are mainly related to landuse and are driven by an increasing demand for water even as it’s supply is decreasing. The consequences of the large reduction in water availability in the basin are quite enormous. Apart from large biodiversity loss, it has also meant damage to the ecological basis that hitherto supported the several millions of people of the region. Thus, farming and livestock production which are the most important activities in the region have been severely impaired, and large movements of population out of the region have been reported.
(ii) Weeds
The major weed infestation in the Lake Chad Basin region is Typha australis (Cattail) which cover about 90% of the area. Typha is genus of about eleven species of monocotoly donous flowering plants in the monogeneric family, Typhaceae. The genus is found in variety at wetland and lakes. The common name are broad leaf, common cattail, Cooper’s Reed, Giant Reed-Male, Soft Nag, Bulrush (UK), Corn dog (America), Cumbugi (Australia), Espadana Comum (Spain), Roseau des Etan (French), Tubna-Langa (Portugese), Kachalla (Hausa).
Typha is often among the first wetland plant and colonize area of newly exposed wetmud. It spreads by Rhizones, forming dense sands often at the exclusion of other plants. Species of Typha grass include:
- Typha angustifolia, Lesser Bulrush or narrow leaf cattail.
- Typha domingensis, Souther cattail.
- Typha Latifolia or australis, common cattalia.
- Typha laximanni, Laxman Bulrush.
- Typha Minima, Dwarf Bulrush
- Typha Muelleri, Raupo
- Typha Orientalis, Raupo.
- Typha Shuttleworthii, Shuttle Worth’s Bulrush.
The species has entangled worth’s bulrush system very rapidly, blocking river canals and taking over the river system as well as the farmland. The species of cattail grass popular known as “Kachalla” in Hausa can be seen over the major rivers that discharge into the lake chad such as the Hadejia/Komodugu-Yobe floodplain in Nigeria, the Chari River in Chad and Logone River in Cameroun.
(iii) Fishing Activities
The Lake Chad Basin was known for it’s high level of fish diversity and fisheries potential: 17 species (Blache, et.al 1964): 87 species (Hopson, 1967): 19 species of commercials importance (Azees and Gubio, 1977). Records for the Nigerian Side show that 23 species were present in 1983( Ajepe, 1983). Sagua (1991) recorded 14 families. The dominant group were cashfish (claries spp. 35% frequency), cichilids (Tilapia spp. 28%) and Heterotis spp. 20%. Presently, there is no accurate data available on the standing stock of the fishery of Lake Chad, though potential maximum sustainable yield for “Normal” Lake Chad put at 100-180,000 million tones/year (Ita, 1995).
Fishing is an important economic activity for people inhabiting the Lake Chad Basin. It was estimated that there are some 20,000 fulltime fishermen in the Lake Chad Basin and about 30,000 people who fish on part time basis. Fishing practice in the lake itself, alone the Chari and Logone rivers and in Floodplain areas of the Lake and rivers. People from different ethnic groups and tribes practice fishing as a means of making a living. Fishing is done according to the seasonal fluctuations of the water in the basin. It is purely catch fishery based on traditional fishing methods and geras, it is mostly unsustainable, there is no regulation of gear type and or appropriate mesh sites. Some of the major problems affecting fishing include diminishing fish stock, high cost of fishing gears, shrinking of water bodies, too many fishermen, invasion of fishing ground by water weeds, and conflict over fishing ground.
(iv) Livestock Rearing
The Chad Basin region represents the most important livestock producing zone in the country, contributing about 30%, 20% and 17% of cattles, goats and sheep respectively to national animal production. Declining fodder availability, desertification, bushfires, diseases and decreased access to water pose serious threats to livestock production in the basin. For instance, Fulani pastoralists are frequently forced to encroach on farmlands due to shortage of fodder on the rangelands. This usually lead to bloody conflicts between farmers and pastoralists.
(v) Irrigation Activities
Large scale irrigation project have been developed within the basin in the last four decades. Those include the SEMRY in Cameroun , SODELAC in Chad and Southern Chad irrigation project and Baga Polder Project (SCIP/BP) in Nigeria. Most of these irrigation schemes, have failed largely due to the recession of the lake and partly due to poor management. The continuous and serious recession of the lake fro 1984 has affected output from crop production in the basin for all the system of production practiced. The southern Chad irrigation (SCIP) in particular was the largest irrigation project in Nigeria in 1974. It was developed with a goal of irrigating 67,000ha with an average of cropping intensity of 130% per year. This was to resettle the 55,000 farming families on the irrigated land. But the plan, was dependent on the lake water level. When the lake level fell below 27.9metres, no irrigation could take place. The system operated only for 6 years with a maximum of 7000ha irrigated. Poor management of the irrigation schemes have contributed to the problem of food insecurity within the basin.
(vi) Climate Change
The Lake Chad basin is highly vulnerable to climate change due to its geographic location at the southern edge of the Sahara desert and the strong dependence of its population on rainfed agriculture and livestock. Rainfall variability , land degradation, overgrazing, and desertification, are some of the factors that combine to make life extremely difficult in this region. The recurrent droughts of the 1970’s and 1980’s (Sahel desiccation) represented a particularly trying episode for countries within the basin, with massive losses of agricultural production and livestock, lost of human lives to hunger, malnutrition and disease, massive displacement of people and shattered economies. The factor responsible for the current state of the environment in the Lake Chad Basin involve a complex interaction of climatic and human forces.
FACTORS RESPONSIBE FOR ENVIRONMENTAL DEGRADATION IN THE LAKE CHAD BASIN
(a) Climatic/Edaphic factors
- Regional and global climate variability
- Persistent droughts
- Desertification
- High rate of evaporation
- Shrinking lake (decline in rainfall)
- Erosion - Etc
(b) Other factors
- Population pressure (total population of the Nation in the region 200 million urbanization).
- Pest
- Poverty
- Increased demand for water and other scarce resources
- Diversion of water by dams for irrigation projects
- Conflict
- Weak political commitment
- Low level of environmental education
- Absence of a regional legal framework for IWRM
- Migration (human and animal)
- Unsustainable exploitation and management of environmental resources
- Etc
CURRENT INITIATIVES INTER-BASIN WATER TRANSFER
In recent time, the idea of inter-basin that would bring fresh water from basins in the wet equatorial region of Africa into Lake Chad has engaged the interest of governments and agencies that have stake in the basin. It is being proposed to move some of the Oubanqui/Congo-Chari River waters into the lake (Sarch, 2000; LCBC Report, 2003). It is estimated that the project would transfer about 900m3/s of water annually from the Oubanqui River in a navigable canal of about 100-150km in length. The project would involve constructing a dam at the danor basin at palambo, which would also be used to produce about 30 to 35 GWH of electricity as well as improve navigation dawnstream of Bangul. This would contribute substantially towards meeting the sub-regions energy requirement (Oyebaride, et.al 2003). The water transfer canal is also expected to enhance the transportation of goods and services within the region. When there is enough particularly within the local area of the basin i.e. the lake, irrigation will become possible and this will boost agricultural production, fishing as well as re-vegetation of large areas of the basin (UN’s IRIN, 2003). On the whole, it will provide an opportunity to rebuild the ecosystem, rehabilitate the lake, reconstitute its biodiversity and safeguard it as the people, if properly educated, informed and empowered, would help maintain the ecology of the area. While this is a laudable project it is constrained by its huge financial requirement and political maneuvering. The affected countries in Africa however seem very committed to addressing the issue.
Baba Ali Mustapha is with Department Planning Research and Statistic Ministry of Environment Maiduguri Borno State Nigeria.
Reference:- Much of my research work was from the book, environmental science, an introductory text by professor Hauna. K. Ayuba and Dr. A. Dami, both of University of Maiduguri, Published by Apani Publication, Bagaruwa Road Costain, Kaduna in partnership with book wrigh (publishers/Ni.,Bodija), Ibadan.
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