Seminar Proceedings Adaptive Water Management in the Lake Chad Basin Addressing current challenges and adapting to future needs World Water Week, Stockholm, August 16-22, 2009 Adaptive Water Management in the Lake Chad Basin Addressing current challenges and adapting to future needs World Water Week, Stockholm, August 16-22, 2009 Contents Acknowledgements 4 Seminar Overview 5 The Project for Water Transfer from Oubangui to Lake Chad 9 The Application of Climate Adaptation Systems and Improvement of 19 Predictability Systems in the Lake Chad Basin The Aquifer Recharge and Storage Systems to Halt the High Level of Evapotranspiration 29 Appraisal and Up-Scaling of Water Conservation and Small-Scale Agriculture Technologies 45 Summary and Conclusions 59 4 Adaptive Water Management in the Lake Chad Basin Acknowledgements The authors wish to express their gratitude to the following persons for their support; namely: Claudia Casarotto for the technical revision and Edith Mahabir for editing. Thanks to their continuous support and prompt action, it was possible to meet the very narrow deadline to produce it. Seminar Overview 5 Seminar Overview Maher Salman, Technical Officer, NRL, FAO Alex Blériot Momha, Director of Information, LCBC The entire geographical basin of the Lake Chad covers 8 percent of the surface area of the African continent, shared between the countries of Algeria, Cameroon, Central African Republic, Chad, Libya, Niger, Nigeria and Sudan. In recent decades, the open water surface of Lake Chad has reduced from approximately 25 000 km2 in 1963, to less than 2 000 km2 in the 1990s heavily impacting the Basin’s economic activities and food security. The shrinkage of the Lake has been driven by both global and local causes: climate change and vastly increased competing demands on the Lake and its surrounding land have accelerated its shrinkage over the past years. The problem of the Lake Chad is actually manifold, as listed below: • The variability of the hydrological regime and the dramatic decrease in freshwater availability. • The relatively high rating of water pollution mainly due to commercial cotton and rice production known to use large quantities of agro-chemicals. • The low viability of biological resources which pertains to the inability of the regenerative rates of the plant and animal resources to keep pace with exploitation and disturbances. • The loss of biodiversity, in particular loss of plant and animal species, as well as damages to ecosystem health. • The destruction and modification of ecosystem due to the change of the Lake from an open water system to a marshy environment. • The sedimentation of rivers and water courses that has led to a reduction in the inflows to the Lake. • The proliferation of invasive species. It is still possible for this situation to worsen in future and this will have significant impact on the local economy, the Lake and its tributaries (Chari and Logone). The Lake’s wildlife and riparian populations inces- santly migrate in search of areas with water around the Lake and their survival is seriously affected. The vulner- able populations are forced onto rural exodus and compelled to migrate across the borders to live as climatic refugees. Several approaches and solutions can be proposed to contribute to saving Lake Chad and in turn provide the almost 30 million people, who rely on the Lake for their livelihoods, with adequate economic and social develop- ment opportunities. Led by the conviction that there cannot be enough water saving from efficient management only, due to the high evaporation, a call was made for the adoption of measures beyond the convention of the available water resources in the Basin. The supply management has, however, been dominating while less atten- tion has been given to demand management. The combination of both as well as the introduction of emergent measures that respond to the global cause of the problem is, therefore, needed within an adaptive framework to save the Lake. This seminar will thus address the current challenges in the Basin and will explore opportunities for an Adap- tive Water Management and possible future strategies to be adopted to replenish the Lake and to safeguard its 6 Adaptive Water Management in the Lake Chad Basin surrounding livelihood. In particular it will address: • The aquifer recharge and storage systems to halt the high level of evapotranspiration. • The Chari-Longone water transfer project. • The application of climate adaptation systems and the improvement of predictability systems. • The appraisal and the up-scaling of water conservation and small-scale agriculture technologies. One of the main challenges that the Lake Chad Basin is facing is related to the high level of evapotranspira- tion caused by the high temperatures throughout the year – a value of around 2 200 mm/year has been estimated for potential evapotranspiration. The high temperatures also limit the potential of natural recharge as most of the precipitation evaporates as soon as it falls. Recharge could be artificially enhanced by injection of clean sur- face water or grey water; or by construction of subsurface dams as it has been applied in Niger. Research studies have shown that high evapotranspiration in the Lake Chad area involves not only surface water but also groundwater. The storage of large volumes of surface water into the underground could surely help to reduce its evaporation. However, the past years have shown that the healthiness of Lake Chad depends very much on the surface water availability or river discharge. Therefore, any conservation methodology like artificial recharge can be applied at small scale, when the needed volumes of water do not significantly reduce the river discharge. Artificial recharge involves injection wells and surface infiltration systems. Due to the fact that injection through wells requires some engineering skills as well as pre-treatment of the water to avoid clogging, this methodology is generally considered as cost-intensive compared to surface infiltration. On the other side, sur- face infiltration needs highly permeable soils and sufficient depth to groundwater to be practicable. However, artificial recharge in the Lake Chad Basin can be applied only at a small scale. Medium to large scale systems require large volumes of water that are also needed for the preservation of the level of Lake Chad. In order to adapt and reduce the harmful effects of climate change, the Lake Chad Basin Commission also engaged in the study of the possibility to adopt a surface water recharge system, through the transfer of some of the waters from the Oubangui Basin to the Lake Chad Basin. The aim of the water transfer project is to construct a navigable channel using some inflows from Oubangui to supply Lake Chad with water. This arrangement will have multiple goals: to ensure river transportation in order to transfer goods from east to west across Africa; to produce electricity; and to develop irrigation and agro-industry in the region. In addition to its capacity for drought control in Chad, the gradual restoration of the level of Lake Chad will also serve as a barrier against Sahara desert encroachment. The project can be used as a real impetus for the rehabilitation of fisheries and irrigated farming on the banks of the Lake and of the Chari River, and it will help to connect LCBC countries to the two Republics of Congo by a navigable channel. Also, the permanent navigability of Oubangui, which flows mainly in DRC and in the Republic of Congo, is vital to the northern areas of the two countries which are accessible only this way. Finally, the project, through the construction of the Palambo dam, will greatly extend the supply of electricity. It is nonetheless necessary to conduct profound and detailed social and environemtnal impact assessment studies, particularly considering the negative impacts the project could have on both the Lake Chad Basin and the Congo Basin. In particular, attention should be paid to the final quality of the water that results from the mix- ing of the waters of the Lake Chad Basin and the Oubangui and the effect this will have on the ecosystems. There are also often public health impacts associated with water transfer canals that can serve as water-borne disease vectors as well as severe impacts on the socio-economic activities (fisheries, animal husbandry, agriculture, etc.). Moreover, the reduction in the flow of Oubangui, as also a result of climate change, is of great concern to the riparian states when thinking about a possible transfer of part of such a volume of water into another basin. Seminar Overview 7 The feasibility study of the project may respond to this need and will identify the main environmental stakes and impacts. The effect of climate change, coupled with several anthropogenic effects, is considered as one of the main causes of the severe depletion of the Lake. Therefore, it is urgent to enhance the traditional climate change adaptation strategies already put in place on the Lake Basin though the development of effective climate predict- ability systems. Humans have been adapting to changing climatic conditions and to the impact of extreme climate events in the Lake Chad Basin for several centuries. Much of this adaptation occurred gradually and spontaneously and the economies of many local communities in the basin to this day still depend on sophisticated production and social systems adapted to manage climate risk and variability. Unfortunately, with increasing population, pov- erty, illiteracy, globalization, coupled with the rapid preponderance of climate related risks in recent decades and the resulting patterns of loss, there seems to a breakdown in the effectiveness of spontaneous adaptation and coping strategies. Knowledge of current adaptation and predictability systems to natural climate variability can reduce vulner- ability in the short-term and provide insights and experience that could enhance resilience to long-term climate change in the Lake Chad Basin, especially as it relates to water management.