Papers by Mouhamed Refaat
Annals of Geological Survey of Egypt , 2019
Near surface geophysical investigation was applied for the engineering purposes through measuring... more Near surface geophysical investigation was applied for the engineering purposes through measuring two transects of the (2-D) Electrical Resistivity Tomography (ERT) and Induced Polarization Tomography (IPT) techniques on the upper plateau of El Mokattam area using Wenner-Schlumberger array with length 235 m and electrodes spacing 5m.The collected data were processed and interpreted based upon the available geological and the hydrogeological information. The (ERT) technique was used for mapping the subsurface rock units, structures and detecting the water-saturated zones or subsurface bearing water layers in the study area, which may be helpful in making the right decision at a late important stage of the decision making for the engineering program. In the study area, the subsurface horizon consists of three units, the top unit is composed of white limestone, the second unit is composed of dolomitic limestone, while the third unit is composed of alternating clay, marl, silt and limestone layers. The (ERT) technique could not clarify nor characterize the water-saturated zones n the lower clay layer that has extremely low resistivity values. So it was necessary for our target to use and exploit the (IPT) technique to overcome this problem and remove this ambiguity, especially as the lower clay layer is characterized by a relative high chargeability values while the bearing water zones were characterized by a relative low or negative chargeability values which ranged around zero value in the inverted chargeability models. The (IPT) technique detected the water-saturated zones in the same layer as well as the fractures which act as a path way for the groundwater.
Annals Geol. Surv .Egypt. V. XXXV (2018), 2018
Hydrogeological study through the analysis of Digital Elevation Model (DEM), together with the al... more Hydrogeological study through the analysis of Digital Elevation Model (DEM), together with the already existing water well information and geophysical survey using electrical resistivity survey have been carried out in El Safa City area, west of Assiut Governorate, southern Egypt. This is to delineate the geoelectrical characteristics of the sedimentary cover of the considered area and to evaluate its groundwater potentiality. A total of fourteen deep vertical electrical sounding stations were established within the site, along four traverses Schlumberger configuration was utilized for the data acquisition. The half-current electrode spacing (í µí°´í µí°µ/2) used range from 1.5 to 4000m. The quantitative interpretation of the VES curves involved the use of partial curve matching and the 1-D computer iteration technique. The interpretation of Schlumberger sounding data was first calibrated with the lithology of the available nearby wells. The depth sounding interpretation results were used to generate the geoelectrical sections, from which the aquifer was delineated. The geoelectrical sections drawn from the results of the interpretation reveal five subsurface layer which comprises of the : a top weathered or surface units of varying resistivity values from (130 to 40000 Ωm), interpreted as a mixture of sediments of wadi deposits, alluvium and clay beds, then a second layer of moderately low resistivity values (20-100 Ωm) comparable to gravel and sand sediments deposits, whose conductivity is due to the pore fluid water and/or these sediments is rich in clay contents; a
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Papers by Mouhamed Refaat