Using hydrochemical and isotopic data to determine sources of recharge and groundwater evolution in arid region from Eastern Desert, Egypt

In arid areas, identifying the recharge sources and hydrogeochemical evolution of groundwater is essential for effective water resource management. The hydrogeological, hydrogeochemical, and isotopic methods are used to understand the origin of water and associated groundwater recharge processes and conceptualize the groundwater flow within the major aquifer systems in the Idfu-Esna Area. In the study area, two main aquifers are studied: the unconfined Quaternary aquifer and the confined Nubian Sandstone aquifer. The groundwater from the two aquifers is characterized by distinct stable isotope signatures. This difference in isotopic compositions is interpreted in terms of difference in origin and recharge mechanisms. The recharge mechanisms are dominated by direct infiltration of precipitation, lateral flow from the surface water and leakage from deep aquifer system through the main faults. The hydrochemical results indicate that the dissolution of carbonate and silicate minerals, leaching of soils and/or ion exchange are the main processes controlling groundwater mineralization. Established conceptual model has clarified the groundwater hydrodynamics within the studied aquifer systems. Based on this model, groundwater mixing can occur between the different aquifers.