Integrated Water Resources Management in the Sandougou Catchment Area (Senegal): Going beyond Soil Defence and Restoration (SDR)

The Sandougou River is the last major right bank tributary of the Gambia River. It has a catchment area of 11,668 km² and is located in Senegalese territory. The flow in this sloping basin (1‰) is favoured by the conservation of soils and vegetation. Since 1970, global rainfall trends (below the average of 800 mm) have shown a drought affecting the whole basin with an average deficit of 100 mm per year. In addition, erosion phenomenon combined with high rainfall intensities explains the rapid run-off. This constitutes a considerable loss of water resources, up to 20% in the Sandougou basin. In this rural area where primary activities predominate, anthropogenic pressure is considerable. Indeed, overexploitation of firewood, resulting from the strong dependence of local populations on this resource, is at the origin of deforestation in the Sandougou basin. Such a situation contributes to environmental degradation and also has repercussions on soil erosion. Erosion affects the water retention capacity of the soil making it more susceptible to extreme conditions such as drought. The impact of soil erosion on more remote sites is not always as apparent as the impact of erosion on the site itself. Sediment reaching watercourses can accelerate slope erosion, silt up drainage ditches and streams, silt up reservoirs, cover spawning areas and reduce water quality. Fertilizers frequently transported with soil particles can contaminate or pollute water sources. To cope with this dynamic, soil defence and restoration (SDR) techniques have long been considered as the solution to the problems. However, the multifaceted nature of environmental problems and their persistence leads to the consideration of a more holistic approach. In the Sandougou catchment area, the application of article R50 of the Senegalese Forestry Code, the implementation of planning tools (AP-IWRM), institutional development in the framework of integrated water resources management (IWRM) prove the interest of such an approach for the protection of water resources.