WRS Masters Defense
No More “Salt by Default”: How snow and ice management practices are developing to mitigate salt’s environmental impacts
When it snows, salt pours. It pours from trucks, buckets, and shovels onto roads, bridges, and walkways all across the Twin Cities metropolitan area. In fact, it happens in developed areas all around the world’s temperate regions. Applying salt to high-traffic surfaces allows foot and vehicle traffic to be less impacted by winter weather, but the practice has been put under new scrutiny in recent years. The salinization of freshwater regions is especially prevalent in environments that are connected to urban areas. This leads to a multitude of ecological stresses such as increased osmotic stress, chloride toxicity among plants and animals, the restriction of lake turnover, the corrosion of metals used in construction, and potential changes to soil structure and mineralogy. Chloride has also been recognized at elevated levels in shallow groundwater, which may threaten deeper aquifers and therefore be a threat to long-term sustainability and security. While the environmental consequences of unrestricted salt loading to environments could be drastic, there have been significant recent developments in winter operations that can help mitigate the related human impacts. This defense will use data and findings from a two-year continuous monitoring and adaptive management study of winter roadway runoff to examine 1) aspects of urban snow hydrology and water quality as it relates to the use of road salt and 2) contemporary developments in snow and ice management practices. This research complements previous studies that examined salt loading and retention on a regional scale.