Geochemical modeling and isotopic approach for delineating water resources evolution in El Fayoum depression, Egypt

Abstract In this study, an attempt was made to understand the hydrogeochemical processes controlling water resources (surface and groundwater) evolution in El Fayoum depression, Egypt. Hydrochemical, inverse geochemical modeling integrated with environmental isotopes applied. Forty-three surface groundwater samples were collected analyzed for major chemistry (cations, anions) stable (δ 18 O, δD). The ionic sequence based on relative molar proportions cations Na + > Ca 2+ Mg K groundwater, respectively anions HCO 3 − Cl SO 4 2− all samples. δ O δD relationship plot a typical evaporation line, enhance potential of recharging prior infiltration. Saturation index estimation revealed that affected by carbonate evaporites minerals dissolution supersaturated Goethite, Gibbsite Barite minerals. Inverse using PHREEQC used identify study area through two flow paths A, B. model constrained so primary mineral phase including calcite, Aragonite, Anhydrite Gypsum Carbon dioxide (gas) are dissolve until they reach saturation, Whereas H 2(g) , hydrogen sulphide out gas models path (A). For (B), Dolomite, tend carbon (gas), gases outgassed. Finally, resource evolution; development cation exchange process aquifer system.