- September 14, 2020
- Posted by: RSIS Team
- Categories: Geography, IJRIAS
International Journal of Research and Innovation in Applied Science (IJRIAS) | Volume V, Issue III, February 2020 | ISSN 2454–6186
Nwosu, Leonard. I.
Department of Physics, University of Port Harcourt, Nigeria
Abstract :- Electrical resistivity method was adopted in mapping sand/gravel beds for commercial mining and delineation of water table in Njaba river bank and environs. To achieve this, 10 vertical electrical soundings (VES) were carried out within the study area. Along the Njaba river bank, one profiling using the Wennerelectrode array was also carried out to determine the lateral extent of the sand/gravel beds. Field data were acquired using the Ohmega-500 resistivity metre and accessories. The Schlumberger electrode configuration with maximum electrode spread of 700m was adopted. At each VES point, the coordinates and elevation were measured using the Global Positioning System (GPS). The field data were interpreted using Advanced Geosciences Incorporation (AGI) 1D software and the Schlumberger automatic analysis version. The results revealed that the area is underlain by multi-geoelectric layers with about 7 to 9 lithologic units identified. Sand and gravel were mapped along Njaba river bank to a depth of about 5 to 10 m and at Amucha erosion site. The beds are thick enough for commercial mining for building and construction materials. The profiling along Njaba river bank shows the lateral extent of the sand/gravel bed with concentration increasing towards the river. The depth to aquifer varied across the study area while aquifer resistivity ranged from 0.10Ωm to 14978.2Ωm. The aquifer is thick enough especially around Njaba area for drilling water boreholes as alternative source of potable water to the polluted Njaba river.
Keywords: Resistivity, Gravel bed, Groundwater, Sand, River bank.
