GROUNDWATER POTENTIAL ESTIMATION USING DAR ZARROUK PARAMETER APPROACH IN NEW FELELE, IBADAN

This study employs the Dar Zarrouk parameter approach to investigate the groundwater potential and hydrogeological characteristics of a basement complex terrain using Vertical Electrical Sounding (VES) data. Eight VES points were analyzed to derive critical geoelectrical parameters such as aquifer resistivity, overburden thickness, transverse resistance, coefficient of anisotropy, and reflection coefficient. The overburden thickness ranged from 16.41 m to 52.37 m, suggesting moderate to good aquifer protection across the area. Transverse resistance values varied significantly from 1,569.04 Ω·m² to 12,508.32 Ω·m², indicating heterogeneous transmissivity and potential for groundwater development, with certain zones exhibiting high-yield prospects. The coefficient of anisotropy ranged from 1.00 to 1.68, reflecting mild to moderate lithological heterogeneity, while reflection coefficients between 0.72 and 1.00 suggest a sharp geoelectric contrast at the basement interface in several locations. All VES points indicated the presence of a weathered layer with medium yield potential, reinforcing the area’s suitability for groundwater abstraction through shallow boreholes. Curve types such as H, KH, and HK further corroborated the presence of conductive and transmissive subsurface layers. Conclusions drawn from the Dar Zarrouk parameters affirm that zones with higher overburden thickness, elevated transverse resistance, and moderate anisotropy are more likely to sustain productive aquifers. Consequently, the study recommends drilling at VES locations with thick weathered layers and high transverse resistance for optimal groundwater yield. Additionally, geophysical results should be supplemented with hydrogeological and pumping test data to improve borehole success rates. This integrated interpretation validates the Dar Zarrouk method as a cost-effective and efficient technique for groundwater exploration in crystalline basement terrains.