DETERMINING THE DISTRIBUTION AND MOVEMENT OF SALT CONTAMINATION IN AN ALLUVIAL AQUIFER IN CENTRAL NEW YORK

Water produced from two municipal wells in Waterville, New York has shown increasing concentrations of sodium and chloride since the wells were installed twenty years ago. Because these ions are not regularly analyzed in municipal water, the elevated concentrations were not discovered until about four years ago, hence the timing of contamination is unknown. An earlier investigation concluded that the source of the salt is an uncovered road salt storage site located about 2 km upgradient of the municipal wells. However, there are no wells between the salt storage area and the municipal wells. The results of the earlier study were based on a combination of numerical modeling and the spatial and temporal variation of chloride in monitoring wells adjacent to the well field and a stream that bisects the area. In our study, we used an electromagnetic induction (EM) tool to map the electrical conductivity of groundwater in the area between the salt storage site and the well field to determine the distribution of salt-affected water in the aquifer. We also studied the stream to examine spatial variability of chloride in baseflow and to determine how seasonal changes in discharge affect shallow groundwater flow and the distribution of salt in the aquifer.