Integrated Geoelectrical and Geospatial Assessment of Groundwater Variation in Selected Location, Port Harcourt, Rivers State, Nigeria
Abstract
Groundwater is the major source of potable water in Port Harcourt, Rivers State, Nigeria, owing to increasing degradation of surface water resources resulting from rapid urbanization, industrialization, and population growth. This study integrates Vertical Electrical Sounding (VES), Geographic Information Systems (GIS), Remote Sensing (RS), and the Analytic Hierarchy Process (AHP) to evaluate groundwater potential and aquifer vulnerability in the study area. Ten VES stations were investigated using the Schlumberger electrode configuration with current electrode spacing ranging from 2 to 200 m. The interpreted geoelectrical parameters were used to estimate aquifer hydraulic properties, including hydraulic conductivity, transmissivity, longitudinal conductance, transverse resistance, porosity, and permeability. Four groundwater conditioning factors, rainfall, geology, lineament density, and soil type, were integrated within a GIS environment using AHP to generate the Groundwater Potential Index (GWPI). The AHP weighting identified rainfall (55.8%) as the dominant groundwater conditioning factor, followed by geology (26.3%), lineament density (12.2%), and soil type (5.7%), with a consistency ratio of 0.045, indicating reliable pairwise judgments. Hydraulic conductivity ranged from 0.0839 to 28.7584 m/day, transmissivity from 6.1 to 853.1 m²/day, porosity from 0.1764 to 0.6870, and permeability from 100.32 to 34,380 mD, demonstrating considerable spatial heterogeneity in aquifer properties. The GWPI map classified the study area into Very Low, Low, Moderate, High, and Very High groundwater potential zones, with the western, northwestern, and central sectors exhibiting the most favourable groundwater conditions. Validation against VES-derived transmissivity showed 100% agreement, comprising 50% excellent and 50% good correspondence between the GIS-AHP predictions and geoelectrical interpretations. The integrated approach provides a reliable framework for groundwater exploration, borehole siting, aquifer protection, and sustainable groundwater resources management in rapidly urbanizing coastal environments.