The ordinates represent the percentages of anions:the percentage of chloride represents sea water and the percentage of bicarbonate or sulfate (depending on the dominant anion in fresh water) characterizes the recharge water. In other words, the percentages of SO2−4 and During the intrusion phase, the exchange reactions are more evident, while during the recovery phase, the water samples are positioned close to the trend line that represents simple binary mixing between fresh water and sea water (although one can recognize facies typical of this new stage by incipient reactions of direct ion exchange).