Application of Electrical Resistivity Method for Groundwater Exploration in a Sedimentary Terrain. a Case Study of Ilara-remo, Southwestern Nigeria
A geophysical evaluation using Electrical Resistivity method for groundwater exploration at Ilara-Remo, southwestern Nigeria was carried out. The investigation involved the utilization of Vertical Electrical Sounding (VES) technique with schlumberger electrode array system. The studied area is located within the sedimentary basin (Dahomey basin) of southwestern Nigeria, ferrigenous sandstone was found to be the major rock type in the study area. The data acquired from the ten (10) VES stations were interpreted using the partial curve matching method and computer assisted iteration technique. The VES results of the data revealed three to five layers which include the topsoil, clayey/sandy clay, clayey sand, conglomeratic sandstones and sandstones/wet sands with resistivity values ranging from 133. The sanstones/ wet sands constitute the main aquifer units. From the overall results the studied area can be classified as prolific zones for groundwater development. INTRODUCTION The availability of quality water resources has always been the primary concern of societies in (Semi Arid and Arid region, even in areas of more abundant rainfall, the problem of obtaining an adequate supply of quality water is generally becoming more acute due to ever increasing population and industrialization.
Geophysical investigations for groundwater in Precambrian terrains: a case history from Ikare, southwestern Nigeria
Abstract Magnetic, very low frequency electromagnetic (VLF) and electrical resistivity methods have been applied in mapping buried bedrock relief for groundwater exploration in the Precambrian terrains of Ikare, southwestern Nigeria. Quantitative interpretation of the magnetic data involved initial modelling and Euler deconvolution using elementary magnetic sources to identify applicable geological models in the spatial domain. A depth estimate of the top of the buried valley of 23 m was obtained. The application of power spectral deconvolution yielded an estimated depth of up to 67 m on the bedrock surface. The VLF data indicated the existence of subsurface lineament in the area while obtained resistivity of the sedimentary fill amounted to 260 ohm-m. The results of the three techniques have successfully delineated a buried river channel for groundwater extraction in a crystalline basement terrain.
RESISTIVITY AND MAGNETIC SURVEYS IN GROUNDWATER PROSPECTING IN VOLCANIC AREAS—CASE HISTORY MAAR OF BEAUNIT, PUY DE DOME, FRANCE*
Volcanic maar structures sometimes contain important groundwater reserves. The volcanic formations of the Beaunit maar have a much higher magnetization than their granite substrata. The structure of the maar and its volcanoclastic infill can therefore be defined by magnetic surveying and resistivity soundings. Resistivities of the geological formations present in the Beaunit maar are comparable to those recorded in other volcanic systems. The geophysical data, confirmed by drilling tests, contain useful information on the hydrogeological regime of the volcanic system under investigation.