Hydrogeophysical Investigation of Groundwater Potential in the Complex Basement of Idu Industrial Area, Federal Capital Territory, Abuja

Abstract

In this study, thirty-six (36) Vertical Electrical Sounding (VES) data points were collected to evaluate the groundwater potential around Idu Industrial Area, FCT, Abuja. Data collection was done with the use of PASI Resistivity meter (model – 16GL-N) adopting the Schlumberger electrode array configuration. The data acquired were analysed and interpreted using the partial curve matching technique and the results obtained were further aided using the Winresist geophysical software. The result of the interpreted VES revealed that the area is characterized by three to five geoelectric layers: the topsoil, weathered layer/weathered (clayey), fractured basement, and fresh basement associated with H, HKH, Q, HK, QQ, KH, and QH curve types, respectively. The topsoil has resistivity values ranging from 66 – 1036 Ωm with a depth range of about 0.7 – 1.4m, the partly weathered, weathered layer, and weathered (clayey) have resistivity values ranging from 37  – 884 Ωm and extend from a depth of about 2.5 – 22.6m, the fractured basement and fresh basement. The fresh basement having resistivity values between the range of 366 Ωm – 9027 Ωm. Out of the 36 VES points, only three (3) fractured zones were delineated for possible groundwater supply beneath VES 18, 21 and 36 respectively. The resistivity values of these fractured zones range from 225 Ωm – 498 Ωm with an average thickness of about 8.8m to 25.8 m respectively. However, the fractured basement represents the aquifer unit for groundwater exploration within the area. Thus, this research revealed that the area has poor groundwater potential due to the relatively shallow depth to the basement rock (thin overburden thickness).