CHLORIDE PATTERNS IN TWO RIVERS LOCATED IN URBAN AND RURAL AREAS IN EASTERN AND CENTRAL MASSACHUSETTS
For this study, we use a robust dataset consisting of continuous temperature, specific conductance and discharge records collected by the USGS from two rivers, one located in a highly urbanized area and one located in a rural setting. Specific conductance values from each river were calibrated to chloride concentrations to indirectly measure the chloride concentrations in each river for their respective periods of record. The Stillwater River is located in central Massachusetts, has a drainage area that is 75.2% forested, and shows a peak chloride concentration under 100 ppm. In contrast, the Saugus River is located in the Greater Boston Area, has a drainage area that is 55.9% urban, and shows a peak chloride concentration greater than 1,000 ppm, above the acute exposure for aquatic life limit suggested by the EPA. Both rivers exhibit seasonal fluctuation of chloride concentrations with peak levels seen during the winter months, when road salt application rates are at their highest point. Here we compare and contrast the chloride concentrations of the Saugus and Stillwater Rivers with respect to time, precipitation, and temperature.