Application of geochemical modeling using NETPATH and water quality index for assessing the groundwater geochemistry in the south Wadi El-Farigh area, Egypt

Abstract

Groundwater quality assessment is of utmost importance for water security in arid areas, such as south of Wadi El-Farigh due to deficiency of recharge, high evaporation rates and groundwater demand for agricultural and drinking utilities. The physicochemical parameters of 25 groundwater samples were investigated. Major ion occurrence was sequenced as Na+ ˃ Ca2+ ˃Mg2+ ˃K+ and Cl− ˃ SO42- ˃HCO3 − ˃ CO3 2- . The main groundwater hydrochemical facies was the (Na++K+) (Cl− + SO42-) type. The studied samples were fresh to brackish and weakly alkaline in nature. The chloro-alkaline indices demonstrate the exchange of Ca2+ and Mg2+ in groundwater with Na+ and K+ from the rock. The water quality index revealed that 80% of samples were appropriate for drinking, 8% were classified as poor, and 12% excellent. Depending on the calculated sodium absorption ratio, the studied samples were categorized as excellent for irrigation. All samples have a good level of residual sodium carbonate. The sodium absorption ratio and electric conductivity were plotted on the diagram of U.S. salinity laboratory and revealed that the moderate and high salinity with low sodium absorption ratio values could cause a negative impact on the crops. It is concluded that, silicate weathering, ion exchange and halite dissolution are the key factors affecting the chemical composition of water in the area of interest. So, the best solution would be to cultivate crops that are resistant to high salinity.

Keywords

• Groundwater
• Wadi El-Farigh
• Egypt
• Hydrochemical analysis
• Water quality
• Geochemical modeling