Visualizing Aquifer Architecture: A Stratigraphic Approach Using VES-Derived Fence Diagrams and Section Plots

Abstract

Understanding subsurface aquifer geometry is essential for effective groundwater exploration and management, particularly in regions facing increasing water scarcity. This study uses Vertical Electrical Sounding (VES) data to visualise aquifer architecture across selected Local Government Areas (LGAs) in south-eastern Nigeria, spanning longitudes 7.00°E to 7.175°E. Section plots and pseudo fence diagrams were used to interpret stratigraphic continuity, depth variability, and the spatial distribution of aquifer intervals to depths of 300 metres. Field-based VES surveys using the Schlumberger array, combined with inversion techniques, revealed a heterogeneous aquifer system, with maximum thickness exceeding 250 metres between 7.050°E and 7.100°E, which is indicative of a depositional depocentre, and thinning towards 7.150°E, suggesting erosional or structural controls. The section plot delineated variable top and bottom depths, ranging from 50 to more than 250 metres, with the thickest interval around 7.12°E. The correlation heatmap showed strong positive relationships between thickness and bottom depth (0.95) and between thickness and resistivity (0.95), reflecting lithological and structural influences. These visualisations simulate geological cross-sections, highlighting aquifer stacking, pinch-outs, and lateral extent, and they are interpreted within a sequence-stratigraphic framework that suggests sediment aggradation, erosion, and tectonic activity. The study demonstrates that VES-derived fence diagrams are useful tools for stratigraphic profiling, providing analytical depth and communicative clarity. It also supports expanded surveys, including electrical resistivity tomography (ERT), to improve imaging resolution and strengthen groundwater-resource assessment.