Exploring Groundwater Resources and Recharge Potentialities at El-Gallaba Plain, Western Desert, Egypt

Egypt has a fast-growing population rate of 2.5%/year; consequently, there is an increase in the water demand for living and launching different development plans. Meanwhile, there is intensive construction of several dams in the upstream Nile basin countries. Thus, it is necessary to search for new water resources to overcome the expected shortages of the Nile water supply by focusing on alternative groundwater resources. El-Gallaba Plain area is one of the most promising areas in the western desert of Egypt attaining the priority for new reclamation projects; however, its hydrogeological setting is not well understood. The present work aims at identifying the recharge potential of the groundwater aquifers in El-Gallaba Plain, as well as exploring the role of geologic structures as natural conduits, and evaluating the groundwater types, origin and distribution. The integration of hydrogeophysical studies (aero and land magnetic surveys, vertical electrical sounding), hydrochemical analyses and remote sensing were successfully used for assessing the groundwater development potential. The hydrogeophysical studies show a large graben bound aquifer with thickness exceeding 220 m. The hydrochemical results indicate the presence of three major water types; Na mix, NaCl, NaClHCO₃ with salinities ranging between 227 and 4324 mg/L. The aquifer receives little recharge from the western fractured calcareous plateau from past pluvial periods and scarce present flashfloods. There is no indication for recent recharge from Lake Nasser to the aquifer domain. Further modeling studies are essential for establishing sustainable abstraction levels from this aquifer.