In the winter most flow comes from shallow groundwater. In order to compare how different ions vary they are plotted as the ratio of each ion with the chloride concentration. Since chloride tends to be conservative, changes in the ion ratio are indicative of geochemical processes occurring in the watershed. The ratio of sodium to chloride is relatively constant while the ratios of calcium and bicarbonate to chloride vary with time. The final graph shows that the ion ratios depend in a systematic manner on flow rate in the river.
High flows represent irrigation releases in the summer.
Low flows occur during the winter months.