An integrated approach to hydro-geological lineament mapping of a semi-arid region of West Africa using Radarsat-1 and GIS

In the 21st century, water resource management will be a major socioeconomic issue and an essential component of progress in semi-arid regions. The Soudano-Sahelian region of Africa suffers from a chronic lack of reliable hydro-geological maps for local water resource managers. To provide better tools for groundwater exploration, this paper focuses on hydro-geological lineament mapping using remote sensing data. The objectives were (1) evaluate the potential of multi-angular and multi-temporal Radarsat-1 images for extracting lineaments in semi-arid regions and (2) provide map of potential hydro-geological lineaments. No significant relationship was found between lineament yield and incidence angle of Radarsat-1 images, while lineament spatial distribution was in good agreement with the land use and geology of the study area. The high scores observed for NNE–SSW and NNW–SSE orientations match the results of local lineament studies of the region. Radarsat-1 image acquired on May 01, 2001 offers the greatest potential, due to the reduced effect of vegetation during this region's dry season. Potential hydro-geological lineaments were mapped using the weighting of well location, presence of green vegetation during the dry season, preferential lineament orientations and presence of cross-points. The mapping revealed five classes (Very low, Low, Moderate, High and Very high) of potential hydro-geological lineaments with high and very high potential poorly represented. Results also reveal that most wells are far enough from lineaments or cross-points and hence the inefficiency of existing drilling programs.