Application of electrical resistivity method for groundwater exploration at the Moghra area, Western Desert, Egypt

Moghra territory is one of the most encouraging regions for watered farming and development in the northern part of Western Desert. To achieve that development groundwater is considered the most favorable tool. Geophysical survey in terms of geoelectrical resistivity sounding has been conducted using the Schlumberger array – eleven vertical electrical soundings (VES’s) were measured on the study area. The aim of this study was to investigate the hydrogeological condition at the area under investigation. Three geoelectric sections are prepared; each of them is composed of four units. The first layer has resistivity ranging from 58 to 2029 ohm.m and thicknesses from 0.46 to 10.7 m characterizing a gravely sand facies of Quaternary age (Pleistocene to Holocene). The second geoelectrical layer has resistivity values ranging between 188 and 518 ohm.m which are comparatively high, with various depths varying between 14.7 and 25.8 m from Lower Miocene age. It is formed of sand and gravel. The third geoelectrical layer is considered the aquifer for the area under investigation with moderate electrical resistivity values (17–111 ohm.m), and could be recognized sometimes as the most extreme depth of penetration. At the maximum depth of penetration of this area, the lower layer (fourth layer) was recognized with the highest electrical resistivity values (1227–8935 ohm.m) of basaltic sheet (Precambrian age). Structurally, the study area is influenced by three faults two of them are geological/geoelectrical faults forming a graben structure at the central part; the third fault is a geoelectrical fault and is located to the west of the graben structure forming a horest structure.