Integration of Geology, Remote Sensing and Geographic Information System in Assessing Groundwater Potential of Paiko Sheet 185 North-Central Nigeria

Abstract

An integrated geologic, Remote Sensing (RS) and Geographic Information System (GIS) techniques have been adopted to assess the groundwater potential of Paiko Sheet 185 North-Central Nigeria in order to reduce failure of developing groundwater resources by delineating prospective aquifer zones from poor aquiferous zones. The study area, which is about 3025 km2, is dominated by crystalline basement rocks comprising of migmatites, granites, amphibolites and schists. Sandstones and alluvial deposits are also present. Digitally enhanced colour composites and band 5 Landsat ETM+ were used to produce thematic maps of lineaments and land use/cover. Shuttle Radar Topographic Mission (SRTM) Digital Elevation Model (DEM) was utilized to map geomorphology and topographic parameters such as slope and drainage systems. Five thematic maps were produced which included land use/ land cover, drainage density, slope, lithology and lineament density. These were integrated and analysed using ArcGIS 10.0 software. All the thematic layers were then assigned weights according to their relative importance in groundwater occurrence and the corresponding normalized weights were obtained based on the Saaty's analytical hierarchy process (AHP). GIS modeling technique employing the weighted overlay method was used to produce groundwater potential map. Four groundwater potential zones were identified namely: “very good”, “good”, “moderate” and “poor”. The spatial distribution of groundwater zones show regional patterns related to lithology, lineaments, drainage systems and landforms. Very high and high potential zones correspond to areas composed of alluvial deposits, sedimentary rocks and high lineament densities. Moderate zones fall on areas within the channel plains, while the low potential zones fall around fresh rock exposures, ridges and peaks which contribute to high run-off. This study has shown that integrating remote sensing and GIS with a sound knowledge of geology is very effective in assessing groundwater potentials on regional scale.