Groundwater potential zone (GWPZ) mapping using analytical hierarchy process (AHP), remote sensing and GIS for Enugu metropolis, Nigeria

Abstract

Enugu state is highly dependent on surface water as a result of the scarcity of ground water resources. The number of boreholes being drilled in and around the city failed because of inadequate groundwater prospecting prior to drilling. This aimed to assess the ground water potential of Enugu metropolis using geographic information system (GIS) and remote sensing. The factors considered were geology, slope gradient, hydraulic conductivity, lineament density, drainage density, rainfall distribution, land use and land cover, geomorphology, and soil type. The Analytical Hierarchical Process (AHP) was used to weigh the various parameters in accordance with their impact on the presence of groundwater in the research area. Thematic maps were developed for each of these factors. The weighted index overlay was carried out and the groundwater potential map produced was classified as very low, low, moderate, high and very high groundwater potential zones covering 16.8%, 26.62%, 22.39%, 19.53% and 14.61% of the study area respectively. It was seen that the metropolis had the worse groundwater potential. The high groundwater potential zone was spread all round the study area but occurred mostly in the north-western part of Enugu State and was the most suitable location for the exploitation of potable water for urban use.