Three Dimensional Modelling of Kharga Reservoir Water, New Valley-Egypt, Using Magnetotelluric Data

Abstract

Most of the Egyptian populations live along the two banks of the Nile River in order to access water for daily needs and other purposes. About 90% of Egyptian territories is a desert with little amount of rainfall. In these arid deserts, groundwater is the only possible source that would support cultivation and civil expansions. Several Oases including Kharga are distributed in the western desert of Egypt, in which the groundwater is the main source of irrigation and daily life. The New-Valley governorate is keen on reclaiming the western desert and developing new urban areas. Previously available boreholes and geological information are used to preliminary evaluate the three dimensional (3D) subsurface structures including the reservoir water and its environment. In this study we utilize magnetotelluric (MT) recordings to spot more light on the Nubian aquifer of the Kharga Oasis. A 3D-MT inversion is applied using “w3dinvmt” code. The resultant 3D-resistivity indicates a low resistive layer associated with a Quaternary aquifer and extends from the surface down to a depth more than 50 m. Low to moderate resistivity values are found to indicate a deep Cretaceous aquifer defined at depths from 250 m to 500 m. A resistive zone is found to exist between them that can be associated with solidified limestone and phosphate layers. Furthermore, a high resistivity value appears to belong to the basement complex of Precambrian rocks in the Oasis. A constructed 3D-model is well matching with major hydro-geological structure of the Kharga Oasis that has been inferred from previous works.