Abstract
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.
[Display omitted] Conceptual diagram of groundwater flow and evolution in the East Idfu and Esna area, Eastern Desert, Egypt. Based on the geologic, hydrogeologic, geomorphic, isotopic and hydrogeochemical analysis, a conceptual model of groundwater flow patterns was developed to understand the groundwater flow and evolution in the study area (Fig. 1). For the studied area, groundwater flows from northeastern to southwestern direction. As the water is recharged and flow, it leaches soluble salts in the unsaturated zone. A cation exchange and dissolution are likely the dominant processes affecting the hydrogeochemical evolution of groundwater. The stable isotope composition of 18O and D in the groundwater indicate that meteoric water is the main recharge source to the groundwater system. Distribution of 18O and D values show a variation from surface water to shallow and deep groundwater.
•Hydrogeological, hydrochemical and isotopic methods were integrated successfully.•The groundwater flow and evolution were studied.•The conceptual model for recharge and flow is developed.•The results confirmed different recharge and flow mechanisms.