Abstract
Groundwater is an essential and vital component of our life support system where it is used for drinking, irrigation, and industrial purposes. Wadi Sayyah is one of the most important wadis in the western part of Saudi Arabia to the northeast of Jeddah city. A total of 42 groundwater samples are collected from hand dug wells in this area and they are analyzed for various physical and chemical parameters. The sequence of the abundance of the major ion is in the following order: Ca2+ > Na+ > Mg2+ > K+ and Cl- > SO42- > HCO3- > NO3-. The dominated hydrochemical facieses of groundwater are: CaCl, and mixed CaMgCl, and the alkaline earths(Ca2+, Mg2+) and strong acids (SO42-, Cl-) are dominating over alkalis (Na+, K+) and weak acids (HCO3-, CO3-). Statistical analysis indicates positive correlation among most of the chemical parameters. Based on the analytical results, groundwater in the study area is generally hard to very hard, fresh to brackish and alkaline in nature. The rock weathering and evaporation are among the most dominant processes in controlling water quality. The chloro-alkali indices illustrate that 80 % of the water samples have positive indicating exchange of Na+ and K+ from water with Mg2+ and Ca2+ from the rock. The suitability of water for drinking and irrigation is determined using WHO standards for drinking; some indices for irrigation purposes and it indicate that the groundwater in the study area can be used for drinking purposes in most of the locations (31 wells), while it is suitable for irrigation uses.