USING REAL-TIME ELECTRICAL CONDUCTIVITY MEASUREMENTS TO UNDERSTAND CHLORIDE IN GROUNDWATER

Chloride contamination is of increasing concern in Minnesota and other northern states and territories. Continued dependence on salt for road deicing in the winter as well as for water softening is leading to increased buildup of chloride in the state’s surface and groundwaters. Traditional groundwater monitoring methodologies provide high-quality data on the concentrations of chloride and many other contaminants. However, the time and cost associated with these measurements make it unfeasible to test large numbers of wells with any regularity. This research aims to use electrical conductivity as a means of measuring chloride concentrations in groundwater aquifers in the Twin Cities Metropolitan Area and how those concentrations evolve over time. Since chloride contributes strongly to the electrical conductivity (EC) of natural waters, measurements of electrical conductivity taken inside groundwater observation wells will provide time series data that can be used to better understand how, where, and to what extent chloride contamination of groundwater is taking place. Preliminary results are presented along with plans for future work.