Contribution of RADARSAT-1 Images to Structural Geological Mapping and Lineament Density Assessment in the Lobo River Watershed at Nibéhibé (Centre-West, Côte d'Ivoire)

Abstract

The populations living in the Lobo watershed at Nibéhibé are experiencing difficulties in obtaining drinking water. This situation is due to several factors, including a lack of control of the hydrogeological environment. The present study assesses the fracture network that has affected the Precambrian basement aquifer of the Lobo at Nibéhibé catchment area by structural mapping and by studying the spatial distribution of the lineaments. To do this, the study exploits the contribution of radar images. Manually and with the use of adaptive and median filters, 1330 lineaments of varying lengths were derived from the RADARSAT-1 image. The validation approach was based on the comparison of the lineament’s orientations of the current study with those of previous studies, and on the position of the geophysically-implanted boreholes relative to the fractures. This approach showed that the lineaments would most often correspond to fractures and would be involved in the occurrence of groundwater. The analysis of the orientation distribution of the lineaments revealed the heterogeneity of the directions and the predominance of the N-S and E-W family directions. The lineament density map showed that the study area is intensely fractured with a proportion of 93%. The results obtained from this thematic map are useful for the implementation of high efficiency hydraulic drilling programmes and for the implementation of water resources management tools.