GIS-based groundwater potential mapping within Dengi area, North Central Nigeria

Abstract

The need for integration of various methods with Remote Sensing (RS) and Geographical Information System (GIS) techniques to increase accuracy in water exploration is undeniable. Spatial observation of the translation of effluent rivers to influent rivers as the flow across the crystalline rock-sedimentary rock contact (CRSRC) led to the incorporation contact proximity thematic layer into the GIS-based model for this research. RS Digital Elevation Model data was used for generation of the thematic maps of slope, lineament and elevation while conventional maps were used to generate the thematic maps of soil, drainage density and drainage proximity. Geological field mapping and ground truthing gave rise to the thematic maps of geology and contact proximity. Weighting of thematic layers was consequently done by pair-wise comparison even as modeling was done by weighted overlay technique in a GIS environment. Groundwater potential modeling of the area revealed three zones: low potential zone coinciding with rugged and high relief areas; medium potential zone coinciding with areas on the crystalline basement with lower relief; and high potential zone which occur in the sedimentary terrain within the study area. In terms of areal extent the low, medium and high groundwater potential zones cover 249, 391 and 130 square kilometers respectively. Groundwater potential map agrees reasonably with field conditions. However, the need for drillers including government agencies to keep data such as pumping test is recommended as it will aid in validating models like this.