Spatial assessment of groundwater degradation using physicochemical analysis and GIS: Case study of the basement complex of Ado Ekiti, southwest Nigeria

Abstract

Spatial assessment of groundwater degradation has been carried out in Ado–Ekiti using physicochemical analysis and Geographical Information System (GIS). Groundwater samples from 108 wells were analyzed on a regional basis. Application of GIS enabled the preparation of various thematic maps which were analysed in terms of groundwater quality standards for drinking and domestic utility. The thematic maps of pH, Total Hardness, Total Dissolved Solids (TDS), Chloride, Calcium and Nitrate concentrations produced were re-classified for integration in a GIS environment to produce the groundwater quality map. Anthropogenic influences were observed on the groundwater quality status of the study area as non-potable groundwater was delineated at the built-up areas and regions adjacent to streams and rivers. The integration of the thematic maps proved useful for the delineation of zones of groundwater quality suitable for human consumption and domestic purposes. Spatial analysis of the groundwater quality is essential for a proper understanding of the present environmental challenges and a projection into the future. This will facilitate quick decision-making for holistic groundwater development and management.