Impact of geologic setting on the groundwater occurrence in wadis El Sanab, Hashem, and Khrega using geoelectrical methods-northwestern coast, Egypt

The present study deals with the complex relationships between the geomorphology and the condition of the groundwater occurrence of three different wadis along the northwestern coastal zone of Egypt in order to provide water for supplementary irrigation and water supply. From the measurements of the geoelectrical techniques (1D and 2D), it is clear that the upstream of wadi El Sanab at the plateau is a promising area where the salinity of drilled well is 2,752 ppm at vertical electrical sounding (VES) no. 1. The delta exhibits lateral facies change that affects the quality of groundwater, and it is clear from the results of water sample analysis of wells. According to the values of resistivity at wadi Hashem, it can be predicted the presence of water-bearing layer may be the third and the last layers. The fifth geoelectrical layer acts as a water-bearing fractured limestone at wadi Khrega, but the potentiality of groundwater is low due to increased clay content that causes low permeability and more salinity in groundwater. Finally, the best side for drilling water wells is in wadi Hashem at VES no. 2 with a depth greater than 75 m. and at wadi Khrega at VES no. 4 with a depth of 70 m. Detecting the save yield for drilled wells is important at wadi El Sanab, especially to maintain the quantity and quality of the groundwater for a long period.