ADVANCED TECHNIQUES FOR DEFINING OPTIMAL BOREHOLE SITES IN LOKOJA’S BASEMENT COMPLEX

Abstract

The best borehole location has been pinpointed using empirically derived aquifer hydraulic parameters. Geoelectric properties were obtained by analyzing seventeen VES data points through partial curve matching and 1D Forward modeling. The study area displayed various geo-electric earth-layer models, with H-type and HA-type curves being most predominant. The conceptual aquifer model revealed a majority of Weathered/fractured systems common in basement complex environments. Aquifer resistivity ranged from 5.6 - 751.6 ohm-m, with lower values corresponding to clay materials. Aquifer layer thickness varied from 1.6 m to 48.3 m, averaging 13.6 m. Hydraulic conductivity in the study area ranged from 0.005 - 11.99 m/day, while transmissivity spanned from 0.03 - 141.6 m2/day. The study area was divided into five groundwater potential zones using the Krasny Classification Scheme. Results indicated that 80% of the area had Very Low and Low transmissivity, appropriate for small water withdrawals only. The optimal borehole location was identified in a small, high-transmissivity area, suitable for regional water abstraction purposes