Groundwater quality assessment in Wadi Fayd, Western Saudi Arabia

Groundwater in Wadi Fayd, western Saudi Arabia, is the main source of water for domestic and agricultural uses. Groundwater occurs under an unconfined condition in the Quaternary alluvial deposits filling the course of the wadi, where water table lies at shallow depths ranging from 1.08 to 27.40 m. Twenty representative groundwater samples were collected from the wadi. These samples were chemically analyzed for major cations and anions in order to understand the different geochemical processes affecting the groundwater quality. Groundwater has variable total dissolved solid (TDS) values ranging from fresh to saline water. Piper plot of the collected samples indicates that Ca and Mg exceed Na and K in most samples, whereas Cl and SO4 are the dominant anions. HCO3 is the predominant anion in few samples, indicating the effect of dissolution of carbonate minerals in the soil and silicates in the aquifer matrix. Groundwater quality assessment for drinking and irrigation purposes was carried out based on TDS, salinity, and sodium hazards. This indicated that groundwater can be used for drinking in some locations based on the WHO drinking water standard. On the other hand, most groundwater is suitable for irrigation purposes based on sodium and salinity hazards. However, soil type as well as proper selection of plants should be taken into consideration.