Assessment of aquifer characteristics and vulnerability to pollution in the Waza Logone Floodplain

Kolja Bosch1, Stefan Broda1, Jörg Reichling1
1 Informationsgrundlagen Grundwasser und Boden, BGR

10.1 in Hydrogeology of Arid and Semi-Arid Environments

The Waza Logone floodplain in the southern part of the Lake Chad Basin represents an important wetland which significantly contributes to the groundwater recharge in this region. The wetland loss, climate variations and the increased human water consumption showed impacts on agriculture, livelihoods and on the functionality of the ecosystem. The impact of these large changes on groundwater resources is still poorly understood because of missing monitoring data and lack of knowledge concerning the extent and the characteristics of the quaternary alluvial aquifer. As an effort improving the data situation and hence conceptual understanding of the flow system, BGR in collaboration with the Lake Chad Basin Commission (LCBC), financed by the German Federal Ministry of Cooperation and Development, drills ~ 50 reconnaissance boreholes including lithological description and construction of monitoring wells on selected sites. The drilling is accompanied with soil and sediment sampling to determine the characteristics of the unsaturated zone and to evaluate the aquifer vulnerability to pollution. In addition, potential point sources and processes, such as intensive agriculture, urban soil sealing and erosion, endangering water and soil resources, are identified using satellite imagery, and resumed in hot spot maps as tools for strategic decision making in spatial planning.