GROUNDWATER POTENTIAL DELINEATION IN ZARIA: AN APPLICATION OF VERTICAL ELECTRICAL SOUNDING (VES) AND WATER SAFETY PLANNING

Abstract

This study presents a geophysical investigation to delineate groundwater potential and assess aquifer vulnerability within the ICSA/Rahmat Hostel area at Ahmadu Bello University, Zaria, Nigeria. In this crystalline basement complex, groundwater occurrence is primarily controlled by the thickness of the weathered overburden and secondary fracture zones. Four Vertical Electrical Sounding (VES) stations were established using the Schlumberger array, with electrode spacing (AB/2) extending to 100 m to ensure sufficient depth of investigation. Data were processed using IP2WIN software to produce geoelectric models. The results identified varying curve types (KH, HKH, and A), reflecting distinct weathering profiles. VES 3 was identified as the most viable location for groundwater development, exhibiting an HKH-type curve with a five-layer model and a weathered overburden of approximately 10.5 m. VES 1 and VES 2 showed moderate potential, characterized by KH-type curves and aquiferous layers exceeding 9 m in thickness. Conversely, VES 4 displayed an A-type curve, indicating a low potential due to the absence of significant fracturing. To evaluate environmental safety, the Total Longitudinal Conductance (G) was calculated. Stations VES 1, 2, and 3 were rated as Moderate, with G values ranging from 0.3370 to 0.3973 S, suggesting the clay-rich overburden acts as a natural filter. VES 4 was rated Poor, offering limited protection. The study recommends prioritizing borehole construction at VES 3 for a sustainable water supply. The paper recommends mandatory hydrochemical screening before water point commissioning, enforcement of borehole construction standards aligned with Nigeria's National Water Policy, and establishment of a formal ABU Campus Water Safety Planning framework aligned with WHO guidelines and SDG 6 commitments.