Integrated geophysical and lithological analysis of a semi-arid karst basin for sustainable water management: Wadi Zouzfana (South-Western Algeria)

Abstract

Semi-arid regions are often characterized by strong spatial heterogeneity of geological formations, surface processes, and groundwater circulation, which critically control water availability and land use planning. This study investigates the subsurface structure of the Wadi Zouzfana basin (south-western Algeria) using an integrated approach combining vertical electrical sounding (VES) and lithological data from three core boreholes (21-30 m depth). Twenty-four VES measurements were conducted using the Schlumberger configuration (= 200 m) and calibrated against borehole logs to establish reliable resistivity-lithology relationships in a karstified carbonate environment. Five main geoelectrical units were identified, corresponding to recent alluvium, karstified limestone, transitional carbonates, weathered dolomite, and compact bedrock. Low resistivity values (100-600 Ω•m) dominate the wadi axis, reflecting water-saturated alluvial deposits and karstified limestone, while higher resistivities (>1200 Ω•m) characterize structurally uplifted carbonate formations along the basin margins. Spatial interpolation of resistivity data within a GIS frame-work reveals an asymmetric bedrock morphology controlled by NE-SW tectonic structures, with a central depression guiding surface runoff concentration and groundwater storage. The results highlight the strong geomorphological and structural control on groundwater distribution and infiltration potential in this semi-arid karst basin. The integrated geophysical-lithological methodology provides a cost-effective framework for site-scale subsurface characterization applicable to similar semi-arid karst environments and supports sustainable water resource management and land planning in data-scarce arid environments.