Abstract
Understanding the processes governing the groundwater chemistry in an area plays an important role in water management and conservation plans. The objective of this study was to assess the factors influencing the groundwater chemistry in Rabigh area along the western coast of Saudi Arabia. To ascertain the factors, hydrochemical data from 49 groundwater samples were analyzed and interpreted using graphical hydrochemical as well as geostatistical techniques. The most conspicuous feature of the groundwater samples was the high EC (average: 5973S/cm) and TDS (average: 3697.25mg/l) values which showed a gradual decrease from the coast to inland areas. Based on interpretation of ionic relationships, Piper plot and extended Durov plot, it is concluded that natural processes such as saline water-fresh water mixing, evaporation, rock-water interaction, and base ion exchanges are the main processes which control the groundwater chemistry. The statistical technique of dimension reduction that is principal component analysis was used to reduce the large dataset to a small number of meaningful principal components (PCs). Five PCs were extracted based on the Eigenvalues which accounted 74.4% of the total data variability. Significant factor loadings of different parameters in each PC supported the findings from the graphical hydrochemical techniques (natural processes) except for PC2. PC2 which showed significant factor loading of K, NO3, and F points towards agricultural pollution in the study area.