Because of its significant salt water content, a small fraction of seawater in the mix dominates the chemical composition of the groundwater. This stage is identifiable through the reverse exchange reaction (1) (NaCa) associated with water salinization, a reaction that is assumed to be instantaneous (Kafri and Arad, 1979). Reactions of direct ion exchange (2) (CaNa), correspond to the freshening stage, and are generally associated with the wet seasons (usually in spring and autumn in Mediterranean countries), with relatively long periods of rinsing.