An integrated assessment approach for fossil groundwater quality and crop water requirements in the El-Kharga Oasis, Western Desert, Egypt

The El-Kharga Oasis in the Western Desert of Egypt is selected as study area due to its hyberarid climate condition and water scarcity. In this region, fossil groundwater main source; therefore, preserving quality quantity mandatory. This evaluated suitability for irrigation purposes assessed requirements cultivated crops optimize supply hyperarid regions. total, 79 deep samples were hydrochemically tested determine by assessing key parameters. Spatial distribution maps all chemical parameters, such pH, EC, SAR, RSC, SSP, TDS, total hardness, Na+, K+, Ca++, Mg++, Fe, Mn, Cl-, SO4—, developed. FAO CROPWAT 8.0 model, based on Penman–Monteith equation, was used forecast agricultural three years, 2010, 2011, 2012. had medium salinity low sodium 84% cases. comparison, high found 16% samples, indicating that can be many soil types with a risk exchangeable sodium. Except 15 wells, chloride concentrations less than 100 mg/l. sulfate ion map showed content extreme western south. annual 2011 2012 199.4, 215.1, 231.7 million m3/year, respectively, reflecting gradual increase approximately 16.57 m3/total area/year expansion area. analysis modern systems reduced amount 32% increased 45% compared conventional methods. Severe depletion occurred during dry season from March July, which exacerbated stress region. results confirmed region under stress. Accordingly, conservation urgently recommended.