Identification of groundwater potential zones in the hard and soft rock terrains of Kogi State, North Central Nigeria: an integrated GIS and remote sensing techniques

Abstract

The availability of groundwater varies from region to region, place to place, sometimes within a few meters and even within the same geological formation. In the study area, an integration of various thematic maps such as geomorphologic, slope, drainage density, land use/land cover maps derived from remote sensing images, geological and lineament density maps and soil map helped in generation of groundwater potential zone map using the weighted overlay analysis in ArcGIS by assigning suitable weights on the Saaty’s scale according to their importance in occurrence of groundwater. However, the assigned weights of the thematic layers and their features were then normalized by using AHP. The groundwater potential zones in the study area were grouped into four classes, and their distributions are: excellent (10.23%), good (51.35%), moderate (34.26%) and poor (4.16%). Excellent groundwater prospect map which covered only 10.23% of the study area falls within the lowlands and plains. For the accuracy of the groundwater potential zone map of the study area based on RS and GIS-based model, it was validated with the data on existing boreholes which was collated for 60 boreholes in the study area and shows positive correlation.