Browsing by Author "Umar ISSA"

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    GEOPHYSICAL AND HYDROCHEMICAL CHARACTERIZATION FOR QUANTITATIVE AND QUALITATIVE ANALYSES OF GROUNDWATER WITHIN ILORIN NW, SHEET 223 SOUTHWESTERN NIGERIA
    (School of Post Graduate Studies, Kwara State University, Malete, 2022-06) Umar ISSA
    The study area covers parts of Ilorin Northwest Sheet 223 which is underlain by the Basement Complex rocks of southwestern Nigeria. The need for groundwater system evaluation within the study area arises to provide a standard database for consumption and Agrarian purposes. The study aims at determining the quantity and quality of the groundwater in the area. The objectives of the study are to determine the groundwater time-dependent variations to obtain the perennial groundwater level fluctuation, analyze the magnetic anomalies to derive lineaments’ distribution, investigate the geophysical study of vertical electrical sounding to establish the potentiality of the groundwater, and, conduct the hydrochemical analysis of groundwater samples of 35 sampling points within the area to determine their quality for human and agrarian usability. The methodology adopted for this research includes; (i) Peizometric measurement of water level in the area for perennial groundwater level fluctuation determination, (ii) analyzing aeromagnetic dataset to obtain magnetic anomalies of the underlain rocks within the area (iii) vertical electrical sounding of Schlumberger array techniques to investigate resistivity changes of the underlying lithologies and, (iv) assessment of groundwater quality through in-situ and laboratory methods. The findings from this study revealed that the area is underlain by lithologies comprising; migmatite gneiss, banded gneiss, augen gneiss, granite gneiss, quartz-mica-schist, and fine grained granite. The time-dependent variation studies show higher groundwater levels in the southern part of the study area than in the rest parts. The magnetic anomalies are also higher in the southern part, while they are moderate and low in the western and the eastern parts respectively. The vertical electrical sounding (VES) identified three to five geo-electric layers; the topsoil, the lateritic horizon, the weathered basement, the sandy clay/clayey sand, and the underlying fractured basement rock with the depth varying from 1.05 to 41.8 m. The range of concentrations of the measured physical parameters; including turbidity (50-470 NTU), pH (3.7-7.9), temperature (29-35 °C) and electrical conductivity (50-940 µS/cm) and average of chemical parameters (mg/l) Ca (0.85), Na (1.23), K (0.35), Mg (0.56), Cu (0.03), Fe (0.03), Mn (0.1), Zn (0.02). Pb (0.03), Cd (0.05), SO4 3- (0.02), PO4 2- (0.11), Cl- (1.43), HCO3 - (65), CO3 - (157), and NO3 - (0.47), fall below the World Health Organization (WHO) standards. The study concludes that the crystalline rocks within the Ilorin Northwest Sheet 223 have a moderate to low permeability, therefore, are aquiferous with modest groundwater potential, especially in the southern part. The high lineament density mapped also confirms the above deductions. The physio-chemical assessment of groundwater samples revealed values that fall below the maximum desirable and permissible limits of the WHO standard, which suggest that the groundwater in the study area is good for human consumption and suitable for Agricultural purposes