الفهرس | Only 14 pages are availabe for public view |
Abstract Geoelectrical resistivity method was used in Wadi Qena area to identify the groundwater resources in the Lower Cretaceous aquifer, and to identify the subsurface geologic setting, the lithologic succession and their thicknesses and the affecting structural elements (faulting and fractured zones). The field survey comprises measuring the apparent resistivity values through 40 vertical electrical soundings (VESes). The well-known Schlumberger configuration with electrode spacing from AB/2= 3 m to AB/2= 3000 m, is selected and applied. 2 profiles were constructed, to cover the study area. An interpretation of the field VES curves obtained from the field measurements have been qualitatively and quantitatively and have been used for construction of two Iso– apparent electric resistivity contour maps at AB/2 80, 850 meters reflecting the variation of the electric resistivity along horizontal planes below the ground surface at depths about 30, 35, 100, 130, 290 and reached to 500 meter and corresponding two geoelectrical – geological sections were constructed along various profiles. The final results revealed that, the qualitative interpretation show that: Wadi Qena and its tributaries can be subdivided into 6 main sectors, meanwhile, the quantitative interpretation show that: the area of study is characterized by the presence of six geoelectrical layers. The depth of groundwater is between 20 m to 30 m, 100 m to 150 m and under 300 m. The groundwater that saturating the subsurface layer is generally brackish to fresh in nature and could be accepted for the irrigation purposes. Within the saturated zones, the high resistivity values the fresher groundwater quality and vice versa. It is recommended by the sites of all VESes for drilling, because these VESes are reached the water bearing zone in the study area. There is a possibility of groundwater findings at depth deeper than 300 m below the ground surface which is fresh water. |