Geophysical Contribution of Using 3D View in Landfill Site
Keywords:Benin City, Evaluate, Leachate, Pseudo section Maps, Apparent Resistivity
Geophysical techniques are very useful tools in the characterization of the subsurface to determine the degree of conductivity and predict the nature of earth materials present within the survey area. Three 2D electrical resistivity profiles were established for the purpose of this research. The field survey was carried out using Dipole-dipole array with a spread of 164 m at the only State government approved landfill site in Ikpoba Okhia local government area, Benin City, Edo State. The 3D image maps were at three different depth slices of (5 m, 18 m and 38 m) in order to determine the rate of spread and migration of leachate as we probed deeper into the subsurface. The apparent resistivity values helped in identifying the nature, lateral spread and depth of the conductive sources in the study area. The resistivity data were imported into Voxler software to achieve the objective of the study. The image results from the electrical resistivity tomography (ERT) method revealed highly conductive zones with conductivity of less than 226 Ωm and above to the depth of 38 m. The images show subsurface resistivity distribution at the Eastern part of the study area trending Eastward with prominence at the center and distributed North - East which has been interpreted as loosed or migration zones of leachate. The depth estimate revealed lateral spread of leachate from the surface to maximum depth (38 m) probed which agrees with the borehole lithology of probable materials present within the study area. The study has revealed that the area is generally highly conductive due to the presences of toxic elements while the loosed zones are prospective locations for infiltration of contaminant plums (leachate) from the 3D model view.
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