Salinity Increasing in Vermont’s Lakes
Prevention is Key to Protection
A new study on increasing salinity levels in freshwater lakes around North America has been in the news recently. The study used data from 371 lakes, including Lake Champlain and several others Vermont lakes. The study found that chloride, the major contributor to salinity in freshwater, has been increasing in many lakes around North America during the last several decades. If the trend continues, chloride levels could become high enough to harm some lake organisms. Much of this chloride is getting into surface waters through winter road de-icing. The study notes that impervious surfaces, such as parking lots, roofs, roads, and other hard surfaces are a strong predictor of chloride trends in the Northeast.
Lake Champlain Impacted
Lake Champlain was highlighted as one of the lakes showing an increasing chloride trend. The Lake Champlain Long-Term Water Quality and Biological Monitoring Project has been
tracking chloride since 1990 and has documented increased chloride in all areas of the lake. Because of these findings and other data from around the Northeast, the Watershed Management Division added chloride criteria to the Vermont Water Quality Standards in 2014, representing the maximum level allowable without harm to aquatic life. The Watershed Management Division and other partners and stakeholders identify watersheds around Vermont with elevated chloride levels so that outreach and chloride reduction efforts can start. While the increasing trend in chloride in Lake Champlain is noteworthy, levels are very low relative to the Vermont Water Quality Standards limits.
Prevention
Winter de-icing practices around Northeast use road salt (sodium chloride) and some calcium chloride to keep roads safe. The Vermont Agency of Transportation and many local municipalities have implemented smart de-icing practices that include applying the amount of sodium chloride needed to keep roads open for travel while reducing the impact on water. Homeowners, business owners, and private maintenance companies can also protect our waters by carefully applying de-icing salts and other products throughout the winter.
To learn more about the harmful impacts of salt on aquatic organisms, read the Watershed Management Division’s summary of chloride impacts. Homeowners and business owners can watch this video to learn about the best tools to remove snow and ice.