Water resource schemes of the Sahel
by Poku Adaa
Two dams are currently being constructed in Senegal and Mali in West Africa to desalinate the Senegal river estuary, to irrigate the entire drought-ridden valley of the river estuary and to tap hydropower. In Nigeria and Chad, the waters of the shallow Lake Chad has been harnessed to boost agricultureSenegal, Mali, Mauritania, Chad and the Nigerian States of Borno, Kano and Kaduna lie in the semi- desert, drought-stricken belt of West Africa. This is an area where pro- longed dry seasons and the downward creeping drift of the Sahara desert have wrought considerable economic damage to the regions and agriculture and peoples' livelihood for many years. Within this dust-blown area lie the Senegal River with its major tributary, the Bafing, and Lake Chad, the mighty oasis of the arid sands.
The Senegal river rises in the Fouta Djalone mountains in Guinea and travels for over 1500 kilometres through Mali where it is joined by the river Bafing at the town of Bafoulabe and traverses the boundary between. Senegal and Mauritania before empty- ing into the Atlantic ocean near the Senegalese port of Saint Louis. Lake Chad forms a common border between Nigeria, Chad and Cameroon. Within the past ten years, attempts have been made to harness these water bodies in order to alleviate the effects of drought on agriculture and to develop sources of hydropower for industrial development.
The Senegal River Development Organisation was formed in 1972 by the governments of Mali, Mauritania and Senegal to jointly develop the entire valley of the river spanning the three countries. The development scheme that emerged from joint studies and negotiations were for the construction of two dams, one in Mali and one in Senegal.
The Diama dam is at the mouth of the Senegal river near the port of St. Louis. Work on this started in 1979 and consists of a 1.6 kilometre wide tidal barrage whose main function will be to blockade the flow of sea-water into the river and hence allow fresh water to be obtained for use in irrigation. The dam has been estimated to cost about $173 million.
The Manantali dam is to be situated on the river Bafing, a tributary to the Senegal in Mali about 90 kilometres south of the town of Bafoulabe. The dam, which will be 208 metres high, will have a water fill capacity of approximately 11x109 kilolitres and power capacity of 800 kw per year. The original cost estimate was $463 million although this had shot up to about $636 million by the end of 1981.
The two projects are envisaged to stimulate development of agriculture, hydro-electric power and industrial resources in the region, 400,000 hectares of land are expected to be irrigated which can support cereals and other crops. Besides, about 900 kilo- metres of the Senegal river will be made navigable to improve transportation to the hinterlands. The projects thus promise a real potential for meet- ing the energy needs of the region and enable bauxite, iron and phosphate deposits in Mali and Mauritania to be exploited.
The three countries have, after tremendous difficulties and delays, managed to obtain funds for the projects, mainly form France, West Germany, the U.S. and several Arab countries. The Manantali dam was started in 1982 and both projects are expected to take ten years to complete. The objectives of the projects were defined by the three governments in a communique issued after one of their several series of meetings in 1982 as:
"To secure and extend the benefits of the River Senegal to the people of the basin and the surrounding areas. To ensure the harmonious develop- ment of human and natural resources within the region and in the affected areas of the three countries. To reduce the deleterious effects of climate on the three countries. To accelerate the economic development of the three coun- tries both by inter-state co-operation and by regional development.
Despite these lofty objectives, the projects have had a considerable number of criticisms from both financiers and environmental groups. France, one of the donor countries has questioned the huge size of the scheme and expressed fears about the ability of the countries to repay the loans and had actively promoted the abandoning of the Manatali dam in favour of the anti-saline dam at Diama.
On the other hand, West Germany, another donor country, has lobbied for the Manantali dam in Mali. A Chinese study team has recommended that Manantali dam ought to be replaced by a number of smaller dams which could be built in stages to spread the cost over many years. Criticisms from environmental groups have centred on the likely impacts of the projects on the social, health and traditional patterns of the people in the region.
The consulting Expert Group, Gannet-Fleming-Couddry-Carpenter from USA, have been reported to have voiced concern over the possible inten- sification of malaria, river blindness, and bilharzia due to the probable creation of vast swampy areas. Independ- ent studies have estimated that up to 13,000 people might be displaced by flooding and that eventually the traditional farming practices of raising food crops such as rice, groundnuts, millet, vegetables and sorghum will be disrupted by the introduction of mechanised agriculture and cash crop farming of sugar and cotton.
Pastoral farmers, who have hitherto enjoyed independence might be taken up under the umbrella of state market- ing and supply agencies with all their inherent social disadvantages and inefficiencies. Thus the project shows a tendency to ignore traditional farming practices and create havoc in the religious and social orders. One effect identified by critics is the absence of a fishing loch at the site of the Diama dam which may have devastating consequences in terms of food nutrition and aquatic occupations.
Landlocked Lake Chad is also another area in the Sahel region where irrigation schemes have transformed a previously barren land. The lake is fed by two rivers, the Yobe and the Chari and because the waters of the lake are not salty, it has been considered ideal for purposes of irrigation. Survey and feasibility studies for harnessing of the waters of the lake began in 1968 by the consulting engineers, M. Macdonald & Partners, and in 1970, a pilot project was undertaken under the initiative of the Commonwealth Development Corporation.
In 1973, the Nigerian government established the Chad Basin Develop- ment Authority to implement a South Chad Irrigation Project. Estimated to cost about $1,000 million, it was one of the largest irrigation schemes in Africa. The scheme consists of the directing of water drawn from the lake through a 29 kilometre intake channel to a main pumping station at Kirinowa. This intake channel was constructed by a Greek-Nigerian company, Edok-Eter- Mandilas Limited. From the main pumping station, a further 22 kilo- metre channel leads to a confluence point where subchannels take the water to the individual plots of land waiting to be irrigated. The whole scheme is a tangled web of some 700 kilometres of channels, canals and other waterways.
The scheme has been criticised for its dependence on fossil fuel for power to operate it. A 30 MW station, diesel- fuelled, has been installed and fortunately, the availability of oil in Nigeria, appeared to provide an easy option for the time being at least. Should extra power be needed in future, it may have to be tapped from the hydroelectric station in Bauchi State nearby where at the moment, an earthfill dam is being constructed on the Balanga River at a cost of £30 million by Balfour Beatty, a British construction comp- any. The face of the arid plains around Lake Chad has been changed dramatic- ally as over 60,000 hectares are being gradually brought under irrigation. Family settlements of 4 hectare hold- ings are being allocated to farmers, however, the priority being given to commercial plantations has eliminated any direct benefit to the pastoral nomads who have lived in the region for centuries.
There is a great need for the authorities to take sufficient notice of the views of the population in these areas and to take measures to redress all possible adverse effects on the people and the environment in which they live.
In the Chad sector of the lake, small dams are being built with assistance from the World Food Programme. Villagers in and around Bol in the plains bordering the lake are actively constructing barrages though self-help community schemes and terrains along the lake are being massively developed for cultivation of rice and other cereals. Water supply and irrigation projects are under way and plans for reforestations are being pursued. At Dongui, north of N'djamena, the capital town of Chad, a research station has been involved for many years in the selection of variants and breeds of cereals for the new conditions of farming around the lake.
At the fourth Afro-Asian Conference of the International Commission of Irrigation and Drainage in Lagos in January 1982, the full benefits of the Lake Chad Irrigation Project was unveiled, with the harvesting of 11,000 tonnes of wheat and 70,000 tonnes of other grain varieties by the end of 1991, eight years after Nigeria initiated the scheme.
The future of the scheme however is causing concern due to the basic nature of the lake itself, Lake Chad is a shallow lake with an average depth of less than 300 cm so that the water level becomes very low during the dry season.
It is therefore not possible for the operators of the scheme to guarantee a sufficiently high and constant water level at all times. On the other hand, even slightly heavy rains can cause considerable flooding of the area currently being occupied by the main pumping station. The shrinking of the water in the dry season due to excessive evaporation increases the fear of less continuous regular irrigation of the agricultural lands.
Taken together, these giant water schemes are all aiming at progress towards agricultural and rural develop- ment and in stemming the march of the desert into the Sahel. There is a great need for the authorities to take sufficient notice of the views of the population in these areas and to take measures to redress all possible adverse effects on the people and the environment in which they live.
"Water sellers" use donkey carts mounted with oil barrels.
UNHCR/K. Burni
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