Geoelectrical Sounding Survey For Aquifer Determination In Some Northern Parts of Edo State - Nigeria

Abstract

31 Geoelectrical soundings investigation comprising 17 soundings in Auchi VES 2 and 14 soundings in Igarra VES 3 all in the northern part of Edo State has been carried out. The aim of the survey was to explore the ground water potential of the areas and ascertain the structures that are needed for the occurrence of ground water. Schlumberger electrode configurations were used for data acquisition which was thereafter reduced to apparent resistivity values. The true depths and resistivity values were determined by curve matching and iterative processing techniques. From the interpretation of results, it was found that ten geoelectrical layers characterized Auchi VES 2 while seven geoelectric layers characterized the Igarra VES 3. For the Auchi sounding, the thicknesses of wet top soil to dry sand vary from 0.71 – 176m with resistivity values of 145 – 8122 ohm-m while for Igarra sounding, the thicknesses of lithology (top soil to fresh basement) ranges from 0.45 – to 16.63m with corresponding resistivity values of 293.00 – 1187.92 ohm-m. A borehole is thus recommended at 25.37m depth for Auchi VES 2 while at Igarra VES 3 a borehole at 8.10m depth is recommended.