Determination of hydraulic characteristics of an aquifer using vertical electrical sounding within the permanent site Adamu Augie College of Education Argungu, NW Nigeria

Abstract

Twenty (20) vertical electrical soundings were acquired using ABEM SAS 300 terrameter in order to determine the hydraulic characteristics of the identified aquifers within Adamu Augie College of Education Argungu near Birnin Kebbi, Northwestern Nigeria. The data were interpreted and seven sounding curves were obtained (KH, HQ, HA, HK, AA, A, and Q). The generated geoelectric sections characterized the subsurface into six lithologic units (topsoil, clayey sand, sandstone, clay, shale and sand) with sandstone and sand constituting the major aquifers in the area. The resistivity layer parameters delineated across the entire area were used to determine the hydraulic characteristics of the identified aquifers. The delineated layers above the aquifers showed transverse resistance ranging from 333.06Ωm2 to 23100.61Ωm2 , longitudinal conductance S from 0.025047 to 1.226506 mhos, hydraulic conductivity K from 0.44 m/day to 25.57 m/day, transmissivity T from 7.144 m2 /day to 465.374m2 /day, and coefficient of anisotropy from 0.98 to 1.0. The protective map shows that about 75% of the area falls within poor overburden protective capacity, 20% constitute moderate protective capacity, while the remaining 5% have good protective capacity rating. Therefore, the hydraulic characteristics of the area suggest that the materials above aquifers are less protected, and by implication vulnerable to infiltration.

Keywords

• geoelectrical method
• groundwater exploration
• transmissivity
• hydraulic conductivity
• protective capacity
• resistivity contrast