Major elements hydrochemistry and groundwater quality of Wadi Fatimah, West Central Arabian Shield, Saudi Arabia

Abstract

Wadi Fatimah is the largest NE-SW trending low topographic area in the west central Arabian Shield, Saudi Arabia. It is bounded by in the NW side by the faulted and folded volcano-sedimentary succession of Fatima Formation and in the SE side by the metamorphic rocks of Jeddah Group. Some massive gabbros and granites and foliated amphibolites are also present along both sides and in the upstream of Wadi Fatimah. The groundwater of Wadi Fatimah is present in the shallow Quaternary alluvial deposits and also in the underlying fractured Precambrian bedrocks. The description of the chemical composition of the groundwater of Wadi Fatimah includes the variations of the groundwater salinity, the major and trace constituents as well as the groundwater character. According to the chemical analysis and the trilinear and durov diagrams, the prevalent chemical character is calcium chloride followed by sodium chloride water types. All the sub-basins of Wadi Fatimah are characterized by a relatively low to medium saline water. Highly mineralized water zone marked the lower part of the wadi, e.g., Al Jumum-Bahrah area, where the groundwater salinity reached up to 26,500 μS/cm with an average of about 9,500 μS/cm. Major and trace elements analyses of the groundwater samples from the different tributaries of Wadi Fatimah revealed its suitability for irrigation purposes.