Determination of the Aquifer System of the Northern Sector of Bida Basin, Nigeria Using Electrical Resistivity Method

Abstract

<p>The northern sector of the Bida Basin extends from Gulu in the south to Kontagora in the north, where it contacts the crystalline rock of the Basement Complex system. It lies between latitudes 5^o80' and 10^o50' N and longitudes 4^o50' and 7^o00' E. The Basin consists of Maastrichtian sedimentary deposits comprising of the Bida Sandstone, Sakpe Ironstone, Enagi Siltstone and Batati Ironstone Formations, with a total sedimentary pile of between 3500 to 4500 m. The aquifer is composed mainly of coarse to medium grained sandstone. Geoelectric survey was conducted using the Schlumberger configuration to a total AB/2 separation of 300 m. 140 Vertical Electrical Sounding (VES) points were established along nine profiles spread across the Basin. The resulting curves were interpreted both qualitatively and quantitatively using visual inspection of the field curve, curve fitting using standard master and subsidiary curves as well as by computer iteration (Interpex IX1D). The results indicate that the dominant curve types are the AA, QQH and KQ. Four groups of curve types were obtained in the Basin, Group 1 (H, K), Group 2 (A, AA, KHK), Group 3 (HK, HKQ, KHKQ, KHKHK, QQH) and Group 4 (QHK, KQQ, KQ, QHK, Q). Based on these four groups the Basin was divided into a northern, central and southern sectors as well as geological contact areas. Geoelectric sections, developed from geoelectric logs show that three types of aquifers exist at various depths; a perched aquifer with a depth of between 5 to 20 m, a semi confined / confined aquifer at between 30 to 60m and an unconfined aquifer with undetermined thickness. The topsoil has a resistivity range of 50-500 Ohm-meters, ferruginised sandstone, 800-2000 Ohm-meters, sandy clay, 150-500 Ohm-meters, sandstone 300-1500 Ohm-meters and clay/shale, 10 to 100 Ohm-meters. The aquifer is represented by the sandstone.</p

Groundwater Investigation Using Electrical Resistivity Method at the Edati Hill, Northern Bida Basin, Nigeria

“…Although there are no available data on the boreholes drill information, 90% of available boreholes here are nonproductive. Previous studies on the groundwater potentials (Aweda et al, 2023;Idris-Nda et al, 2013) have been focused on adjoining areas which have different physiography and water challenge from the study area. The study is aimed at understanding the subsurface distribution of the aquifer in the area, its depth, thickness and resistivity, using electrical resistivity methods with the objective of upgrading or upscaling drilling success rate in future.…”

Groundwater geochemistry and hydrochemical processes in the Egbako aquifer, Northern Bida Basin, Nigeria

“…The study area sits in the northern Bida Basin where groundwater provides over 80% of water need for domestic and agricultural activities. Previous hydrogeological studies here have focused on estimating the depth to aquifer and their hydraulic properties (Idris-Nda, 2012;Olabode et al, 2012;Idris-Nda et al, 2013) as well as assessing the groundwater quality and their suitability for human consumption (Idris-Nda et al, 2016;Sidi et al, 2016;Amadi et al, 2017;Ashafa et al, 2020). Findings from these studies revealed elevated concentration of nitrate and sulphate arising from intensive use of agrochemicals for agricultural and anthropogenic activities, with no study focused on understanding the relationship between the hydrochemistry and processes influencing them.…”