HYDROCHEMICAL EVALUATION OF THE AZRAQ UNCONFINED AQUIFER, JORDAN
The groundwater hydrochemical characteristics of the Azraq Basin were investigated and evaluated statistically. The presence of an underground saline water body in the Qa’ Al-Azraq area has made this specific part of the basin. 38 samples from 38 GW wells were collected to understand the GW hydrochemistry of the Azraq unconfined aquifer that is mainly composed of marl, evaporites, limestone and clay formations. The PCA analysis indicates that Na, Mg, Cl, Ca, and K contribute the variance in the chemical composition of the GW samples. Piper, Durov and Wilcox diagrams indicated that the water types are mainly earth alkaline with prevailing SO4 and Cl, and alkaline water with prevailing SO4 and Cl. The main processes in the basin are dissolution or mixing and reverse ion exchange in which Na and Cl are prevailing. The GW is mainly oversaturated concerning aragonite, calcite and dolomite as indicated by the excess input of Mg and Ca ions from the rock-water interactions, while anhydrite (CaSO4), halite (NaCl), and gypsum (CaSO4.2H2O) are generally undersaturated. The effect of the agricultural activities in the study area is reflected by the positive correlation between NO3 and PC2. Wilcox diagram indicates that the samples are in the medium to very high salinity slots with the majority in the high salinity slot and in the low and medium alkali hazard zone, while few samples show high to very high alkali hazards. The simulated salinity for the next 30 years shows alarming danger and requires immediate attention as the Qa’ area is expected to become saline with TDS values of 2500 to 4600 mg/l, unsuitable to use for domestic and/or agricultural purposes.