Aquifers Characterization and Classification Using Electromagnetic and Galvanic Resistivity Methods in Basement Complex, Katsina-Ala, Central Nigeria

Abstract

Integrated approach involving electromagnetic (EM) and vertical electrical soundings (VES) have been used in this research to map out, characterize and statistically classified estimated characteristic in order to develop underground water productivity map in a basement complex terrain of Katsina-Ala, Central Nigeria. 15 EM conductivity traverses were carried out using Geonics EM-34 from which qualitative interpretation of conductivity data revealed points of inflexions which were subjected to further investigation using VES. A total of 26 VES points were occupied in the present study using ABEM Terrameter SAS 300C for Schlumberger array at half current spacing of 65 m to 160 m, from which geo-electric parameters were determined. A χ transform equal to 10.7762  was estimated from the result of borehole pumping test conducted carried out in the area which effectively transform geo-electric data into hydraulic parameters. Thus, hydraulic conductivity ranging from 0.0672 m/day to 0.4854 m/day with average of 0.2 m/day and transmissivity ranging from 0.8621  to 12.9520  with average value of 4.7133  was estimated. Statistical classification Transmissivity values estimated revealed three classes; very low, low and intermediate classes with a variation of 0.3264 which signified a fairly heterogeneous formation thus justifying the use of our χ transform in the area.