GROUNDWATER PROSPECTIVITY MAPPING USING INTEGRATED GIS, REMOTE SENSING, AND GEOPHYSICAL TECHNIQUES; A CASE STUDY FROM NORTHEASTERN NIGERIA

Abstract

An integrated GIS, Remote sensing, and Geophysical techniques has been successfully applied to generate the previously non available groundwater prospectivity map for the present study area. Selected thematic maps were integrated using the weighted sum tool of the spatial analyst tool of the ArcGIS software. The five thematic maps used are: lithology map, drainage density map, slope map, lineaments density map, and the topographic map of the area. The groundwater prospectivity map generated was reclassified into low, moderate, high, and very high potential zones on the basis of their assigned layer rank, which also depends on their degree of influence on groundwater occurrence. Areas around Gombe, Wuyo, Deba, Alkaleri, Kaltungo, Misau, Nafada, Bajoga towns are the regions that showed very high prospects for groundwater occurrence. Data processing filters such as: horizontal derivatives, Analytic signal processing, 3d-euler depth estimation was applied on the magnetic data in order to map structures and lithologic contacts before its subsequent integration with other structural lineaments as a thematic layer. Vertical electrical sounding (VES) data were used to compute hydraulic conductivity, and Transmisivity etc. for the acquiferous layers identified. The results of the present study showed some regions that are classified as highly prospective to be consistent with high Transmisivity and high yield values. The final outcome (groundwater potential map) of this research demonstrated that GIS/remote sensing, and the geophysical technique employed is a very powerful tool for generating groundwater prospectivity map, which is very vital in terms of planning for groundwater exploration and exploitation.