Vertical Electrical Sounding for Groundwater Vulnerability in Arochukwu South Eastern Nigeria

This study focuses on the application of the Vertical Electrical Sounding (VES) technique to assess groundwater vulnerability in Arochukwu, Southeastern Nigeria. The Vertical Electrical Sounding (VES) method, utilizing the Schlumberger electrode arrangement, was employed to map subsurface resistivity profiles at four locations (VES 1 to VES 4). This method involves placing electrodes in a specific configuration to measure resistivity, enabling the identification of potential aquifers and assessing their susceptibility to contamination through detailed analysis of resistivity variations across different depths.The research aims to provide insights into sustainable groundwater management by analyzing the subsurface structure and distribution of aquifer zones.The study involved the collection and analysis of resistivity data, which were used to model subsurface profiles. The computer-modeled curves showed a root mean square (rms) value of less than 4, indicating high accuracy in the modeling process. All VES points produced Q-type curves, suggesting consistent subsurface conditions favorable for groundwater accumulation.Quantitative results indicated significant variations in apparent resistivity, depth, and thickness of the subsurface layers across the study area. VES 3, located in the central part of the study area, recorded the highest apparent resistivity of 3263 Ωm for the topsoil, while VES 1 in the northern region had the lowest resistivity of 301 Ωm. The depth and thickness of the topsoil also varied, with VES 3 exhibiting the deepest and thickest topsoil layer at 1.32 meters. The resistivity of deeper layers showed a similar trend, with the highest values at VES 3, suggesting a more resistive material composition in the central region.Qualitative analysis of the data indicated that the subsurface conditions in Arochukwu are favorable for groundwater storage, particularly in the central and southern parts of the study area. The variation in resistivity, depth, and thickness across different VES points highlights the spatial heterogeneity of the subsurface layers.The discussion underscores the importance of understanding these variations for effective groundwater management. The correlation between the modeled and theoretical curves reinforces the reliability of the VES technique in delineating aquifers and assessing their vulnerability to contamination. This study provides valuable insights into the subsurface characteristics of Arochukwu, contributing to the sustainable management of groundwater resources in the region. The novelty of this research lies in its comprehensive analysis of aquifer vulnerability using VES data, offering a robust framework for groundwater exploration and management in similar geological settings