Browsing by Author "Abdulkadir, Kamil, A"
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Item Comparison of Six Classical Electrode Arrays of 1D Resistivity Survey for Subsurface Delineation – Field Experiments(University of Ilorin, Nigeria, 2020) Raji, Wasiu O; Ibitoye, Philiphs E; Abiri, Olufunmbi A; Adepoju, Jamiu, A; Abdulkadir, Kamil, ASix classical Traditional Resistivity Survey methods comprising Schlumberger, Wenner, Dipole-dipole, Wenner-Schlumberger, Pole-dipole and Pole-pole arrays were tested for subsurface stratigraphic delineation in a series of field experiments conducted in the basement complex area of Ilorin, North central Nigeria. The aim of the study is to determine the suitability, strength, and weakness of the different array system for subsurface stratigraphic delineation. Interpretations and comparisons of results from the different arrays were based on the lithologic sections obtained from borehole drillers’ logs in the study area. The results of the study showed that some arrays are more reliable for geo-electric layer delineation than others. Wenner-Schlumberger and Schlumberger arrays gave the overall best results in terms of estimating the vertical extent of layers and depth to hard rock (fresh basement rock). Wenner-Schlumberger array proved to be a reasonable alternative to Schlumberger array when strong vertical resolution is needed. Dipole-dipole, pole-dipole, and Wenner arrays consistently underestimate the number of horizontal layers in most of the study locations, thereby suggesting low sensitivity of the methods to vertical resistivity changes. In situations where the four electrodes cannot be situated within the vicinity of the target, results of the study showed also that pole-pole rather than pole-dipole is a better method of resistivity survey. Interestingly, none of the methods is one hundred percent accurate when compared to the borehole lithologic sections. The study recommends Schlumberger and Wenner-Schlumberger methods for high-resolution subsurface delineation in the study area. Descriptions of the field procedure and electrodes arrangement for the six classical arrays are detailed in this paper with the goal of providing guides to non-professional geophysicists like Agriculturists, Civil and Water engineers, and new-comers in the discipline of geosciences who sometimes engage traditional methods of resistivity survey for testing soil and concrete material and citing water-wells /boreholes.Item ) Evaluation of groundwater aquifer vulnerability in Ilorin Metropolis Using Electrical Resistivity Method of Geophysics(European Water resources Associiation, 2019) Raji, Wasi O; Abdulkadir, Kamil, A; Rahman, Rasak, AAn area of 321.97 km2 in Ilorin Metropolis has been studied, using 312 Vertical Electrical Sounding data obtained in an intensive Electrical Resistivity Survey. The goal of the study is to evaluate the vulnerability of groundwater in the area to contamination with a view to advise Kwara State Government on the safe sites for locating the planned public water project in the different parts of Ilorin. VES data acquired in the area were subjected to manual and computer-aided interpretations to delineate the different geo-electric layers, their hydrogeological significance, and vulnerability of the aquifer. The area was divided into zones, namely, A, B and C. Results of the study revealed presence of five geo-electric layers and two groundwater aquifer layers. The first aquifer corresponds to weathered rock layer, has hydraulic conductivity ranging from 0.1 and 3.0 m/day, lies at shallow depths ranging between 2 and 36 m, and has overburden material whose protective capacity (𝑠) against groundwater contamination is weak (𝑠≤0.19), except in few places in zone C where protective capacity is moderate (0.2≤𝑠≤0.69). The second aquifer layer corresponds to fractured basement rock, lies at depths ranging between 5.0 and 53 m, has overburden layer whose protective capacity against groundwater contamination ranges from moderate (0.2≤𝑠≤0.69) to good (0.7≤𝑠≤4.9). Groundwater in fractured basement rock aquifers is more protected against contamination from dumpsite leachates and anthropogenic wastes than the groundwater in the weathered rock aquifers. Joint interpretation of hydro-dynamic properties of the overburden and aquifer layers of the three zones showed that zone C has the highest groundwater protection capacity, while zone A has the least protection capacity against contamination. Different safe spots were identified for citing boreholes for potable water supply in the three zones. The study recommended that all boreholes for portable water supply, except in few places in zone C, should penetrate the fractured basement rock aquifers to avoid the supply of contaminated groundwater in the future.