Hydrogeophysical study at an arid area: case study at Ayun Musa hot springs, Sinai, Egypt

A geoelectrical resistivity survey supported by hydrochemical analysis was managed in Ayun Musa area to detect the groundwater aquifer, differentiate the subsurface layers and estimate the groundwater quality of Ayun Musa springs. A suit of 29 vertical electrical soundings (VES) of AB/2 varying from 1 up to 1000 metres were measured in the study area to achieve the goals. Water samples were collected from ten localities in the study area. Interpretation of the VESes using 1D and 2D algorithms indicates the presence of five geoelectric units of different resistivities. The main water bearing formation related to the Lower Cretaceous represented by the fifth layer and located at depth range from 205 to 256 m below the surface. On the other hand, Interpretation of hydrochemical analysis reveals that the groundwater in Ayun Musa area is brackish in nature. The sequence of the abundance of the major ions is in the following order Na+> Mg+2 > Ca+2 and Cl−> SO4−2> HCO3−. This suggests active dissolution and ion exchange processes and the high chloride and sodium concentrations indicate a major influence by seawater. Generally, the groundwater samples in the study area are not suitable for domestic purposes.