Detecting Salinization of a Small, Rural Watershed and Municipal Water Supply: Road Salt, Infrastructure Risk, and Monitoring Approaches in Hamilton, New York, USA

Road salt-driven salinization threatens drinking water quality, public health, and water infrastructure in cold-climate regions, such as central New York. While rising sodium and chloride levels in surface water and groundwater are well-documented in the Mohawk River basin and Adirondacks region, the extent of salinization across New York are unknown. Here, we provide a case study examining salinization of Payne Brook, a losing stream connected to the shallow alluvial aquifer that is used by the village of Hamilton, New York, as a municipal drinking water supply, to evaluate whether deicing practices are salinizing Hamilton’s surface waters and how salt runoff may affect groundwater quality, infrastructure, and public health. By combining analysis of historical water quality data with seasonal surface-water sampling and complementary weather and stream-gage time-series data, we find steadily increasing sodium concentrations over time in Hamilton’s village water supply and indicators of road salt inputs characterized by elevated chloride-to-sulfate mass ratios in Payne Brook water that are consistent with a high potential for infrastructure corrosion. As a result of engaging with this case study, readers will learn how low-cost monitoring can detect potential freshwater salinization. The case study provides a framework for comparable municipalities looking to maintain winter road safety while preserving freshwater resources and reducing risks to public health.