الفهرس 
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Abstract
Egypt — the most populous country in the North African Sahara — is observing one of the highest water budget deficits in the world of more than 40 BCM/yr., which necessitates the water augmentation and the expansion of using unconventional water resources. The water deficit in Egypt is expected to be aggravated under the ongoing upstream damming on the Nile River and climate change. Groundwater exploration and aquifer characterization using integrated remote sensing and geophysical techniques have been proved efficient in several locations in Egypt. The present study utilized optical and radar satellite images to examine the various geological and geomorphological features that can be indicative of groundwater occurrences in Wadi Diit, Shalateen -Abo Ramad area, south Eastern Desert. Nine vertical electric soundings (VESs) and eleven 2D electrical resistivity profiles (ERTs) were conducted to characterize the subsurface layers and assess the groundwater potentiality. The preliminary findings suggest that the study area is dominated by a large-scale alluvium fan setting (i.e., sand and gravel over an area of approximately 450 Km2) and is surrounded by an assemblage of igneous and metamorphic rocks. Given that the large-scale alluvial fan represents the termination of major catchment with up to a seventh stream order, and that the southeastern Desert catchments receive a relatively considerable rainfall (i.e., average annual rates between 100-200 mm), the surficial analysis suggests a high potentiality of groundwater in Wadi Diit alluvial fan contingent to suitable subsurface setting. The integration between satellite-derived digital elevation model (DEM), optical satellite images (i.e., Sentinel-2 and Landsat-9) and rainfall data (Climate Hazards group Infrared Precipitation with Station [CHIRPS]) indicated that the average annual precipitation is 41.8 mm/year over the entire catchment between Egypt and Sudan and the volume of annual precipitation attains 2.035 m3 /year. Given that Wadi Diit basin share similar geological and hydrological characteristics with Wadi Hodien basin (Milewski et al., 2009), thus the soil and water assessment tool (SWAT) model-estimated transmission losses for Wadi Hodien that attained 19.4 % of the total volume of precipitation can be adopted for Wadi Diit basin. The application of the same percentage for Wadi Diit yields a total volume of transmission losses equal to 394 x106 m2, which is considered as the average annual recharge to the aquifer in Wadi Diit. Inspection of the geophysical results indicate that the subsurface of Wadi Diit alluvial fan is mainly composed of four geoelectric layers: (1) dry heterogeneous surficial layer with high true resistivity values of up to 3000 Ohm.m and an average thickness of 10 m, (2) saturated sandy layer with brackish water (i.e., the aquifer) with resistivity range between 39 and 94 Ohm.m, (3) quaternary sediment saturated with salt water with resistivity values of up to 26 Ohm.m., depending on the depth to the basement complex. (4) massive basement rocks with high resistivity values between 149 to 1095 Ohm.m. Preliminary results indicated that there is a high potential for groundwater exploration in Wadi Diit, south of the eastern desert in Egypt, in light of high structural control over groundwater flow, conditional on a suitable subsurface situation. More sophisticated analyses and additional 2D electrical resistivity tomography profiles should be conducted to better characterize the aquifer subsurface materials such as the clay lenses, fractured basement units, and sandy layers saturated with saline water near the coastline.