Geo-electric techniques for estimating and mapping the electro-geohydraulic properties of the shallow aquifer within the Nsukka Formation in eastern Nigeria/Tecnicas geoelectricas para la estimacion y mapeo de las propiedades electro-geohidraulicas en los acuiferos poco profundos en la formacion Nsukka, en el este de Nigeria

This study, employing Vertical Electrical Sounding (VES), was carried out within parts of Nsukka Formation located in southeastern Nigeria in order to determine the subsurface properties that aid in characterizing the subsurface. The study covers parts of Nsukka, Enugu Ezike, Obukpa and Eha Alumona in Enugu State, characterized by undulating terrain and a tropical climate with distinct wet and dry seasons. Twenty-one sounding data were acquired, and the measured data were quantitatively and qualitatively interpreted to determine the geoelectrical parameters. The interpreted resistivity curves revealed five geoelectric layers with different generic curve types. The secondary parameters estimated from modeled equations and their spatial distributions are displayed in the contour maps generated with Origin software. The estimated parameters - longitudinal conductance, transverse resistance, transverse resistivity, longitudinal resistivity, anisotropy, porosity, hydraulic conductivity, permeability, formation factor, and tortuosity-vary across the study area within the following ranges: 0.01 - 0.54, 373.90 - 11375.00, 109.56 - 5402.14, 108.72 - 4046.87, 1.01 - 1.88, 0.276 - 0.314, 0.187 - 3.509 m/day 1.02E-5 - 9.32E-6 mD, 3.092 - 3.780, and 0.200 - 1.021, respectively. The variation of these parameters may be influenced by the heterogeneous nature of the subsurface. The regression analysis reveals the mutual relationships and correlation between the different parameters when plotted against each other. The results from this study are very promising, and demonstrate the efficacy of the geophysical approach in characterizing the subsurface for sustainable groundwater management and protection. The deployment of geo-electric indices in this study is to ensure adequate characterization of the subsurface. Keywords: anisotropy; groundwater; geoelectric layer; resistivity; VES Este estudio, realizado con pruebas de Sondeo Electrico Vertical (SEV), se llevo a cabo en algunas partes de la Formacion Nsukka, ubicada en el sudeste de Nigeria, para determinar las propiedades que ayuden a caracterizar el subsuelo de la formacion. El estudio cubre partes de Nsukka, Enugu Ezike, Obukpa y Eha Alumona, en el estado de Enugu, caracterizado por terrenos ondulados y un clima tropical con distintas estaciones humedas y secas. Se recolecto informacion de 21 sondeos y esta informacion se interpreto cuantitativa y cualitativamente para determinar los parametros geoelectricos. Las curv