Application of Statistical Methods, Saturation Indices, and the Composite Diagrams in the Groundwater Quality Assessment in the Kerman Plain Aquifer

The hydrogeochemical characterization of the Kerman plain aquifer, in central Iran, has been studied. Chemical characteristics from 58 deep well samples were used. Physicochemical characteristics and the major elements (Na+, K+, Ca++, Mg++, Cl-, SO4 - - and HCO3 -) were analyzed for these samples. Different methods including composite diagrams, saturation indices, and multivariate statistical methods were employed to assess groundwater quality. The results showed that the main hydrochemical facies of the aquifer representing 73% of the samples samples are (Na, K– Cl, SO4). The solubility of Calcite, Dolomite, Gypsum, and Aragonite were assessed in terms of the saturation index indicating supersaturation with respect to Calcite and Dolomite. Clustering analysis showed three distinctive groundwater groups indicating different groundwater residence time and different rock-water interaction history. The results of factor analysis indicated that five factors explain about 96.3% of the total sample variance. The first and most important factor is mainly controlled by Halite dissolution in the Kerman plain. Dissolution of Gypsum is the second most important source of salinity.