Contribution of Remote Sensing and GIS to the Mapping of Fractured Reservoirs in the Donga Department (Northwestern Benin) for a Sustainable Management of Their Resources

Groundwater is a vital resource for meeting the freshwater needs of communities. The objective of this study is to map the hard rock aquifers of the Donga department and to analyze their hydrodynamic properties for a rational management of their resources. The methodology adopted starts with the use of OLI images for the mapping of fracture networks using spatio-directional filtering methods. Then GIS was used to generate the fracture-induced permeability map and the node map formed by the fracture intersections. Structural mapping using remote sensing generated a major fracture map with 745 fractures that could form hard rock aquifers. The calculated transmissivity values range from 3.01 × 10−07 to 4.88 × 10–03 m2/s. The fracture-induced permeability values range from 1.224 × 10−8 to 3.75 × 10–6 m/s. The fracture-induced permeability map reveals three main groundwater flow corridors and reservoir recharge axes. The node density map has 27,665 nodes with an average of 165 nodes per grid cell.