Investigation of aquifer plausible zones and their protective capacity using hydraulic parameters in Modomo/Kajola, Ile-Ife, Southwestern, Nigeria

This study investigates aquifer plausible zones in Modomo/Kajola, Ile-Ife, using Dar Zarrouk parameters. The area, located in Universal Traverse Mercator (UTM) Zone 31N and characterized by pegmatite and granite gneiss in a Basement Complex terrain, spans between 830,000–830,500 mN and 663,000–664,000 mE. Twenty-eight Schlumberger-array vertical electrical soundings (VES) with AB/2 values from 1 to 155 m were performed using a Terrameter SAS 300C. The VES data, interpreted through partial curve matching and computer-assisted iteration, revealed three to five geo-electric layers: topsoil, lateritic/weathered layer, partly weathered basement, fractured basement, and fresh basement. The main aquifers comprise weathered materials (clay, sandy clay, clayey sand, and sand) and weathered/fractured basement, with aquifer thickness ranging from 3.3 m to 15.8 m (mean 9.9 m). Hydraulic properties indicate that longitudinal conductance varies from 0.00171 to 0.34848 mhos (mean 0.028467 Ω), hydraulic conductivity from 0.0000435 to 0.038079 m/day (mean 0.01858 m/day), and transmissivity from 0.00025 to 0.50456 m²/day (mean 0.20158 m²/day) while the GSLI ranges from 2 to 4 (mean 3). Overall, the area exhibits very low to medium aquifer potential, with the region around VES 7 favorable for groundwater abstraction.