IntroductionHydrogeochemical modeling of an aquifer cannot only characterize the spatial and temporal variations, but can also be useful in understanding the interaction between the groundwater and the aquifer matrix. Different techniques and methods of studying the chemical composition of the groundwater provided an understanding of the main factors that contribute to the groundwater salinity (Hammer et al., 2005, Wischusena et al., 2004). Composite diagrams have been used as a tool to interpret the groundwater chemistry data in various parts of the world. Back (1966), Howard and Mullings (1996), Marie & Vengush (2001), Gosselin et al. (2001), and Cloutier (2004) used composite diagrams to identify salinity sources. The saturation indices (SI) for representing minerals of the rock can serve as a useful tool in understanding the interactions between the groundwater and the host rock. Calculation of these saturation indices has been performed by a number of researchers (Nordstorm et al., 1989, Jeong, 2001).