Strategies to help mitigate chloride from road deicers
U of M researchers measured the transport and accumulation of chloride from road deicers in a metro-area watershed. Their findings revealed a greater infiltration of chlorides into soil and subsurface waters than was previously assumed.
“The results will help investigators and policymakers explore ways to capture chlorides and mitigate their damaging environmental effects,” says William Herb, a research associate with the U of M’s St. Anthony Falls Laboratory.
Overall, the team observed substantial chloride retention via infiltration to soils and groundwater. Researchers also found that winter rain-on-snow events and the first major prolonged thaw each season moved surface chlorides most effectively into the watershed.
The research team used the data and modeling to examine potential strategies for reducing or mitigating the spread of chloride, including capturing low flows, seasonal runoff capture, and capture based on salinity.
“Based on this research, we now know that deicer chemicals are staying in the soil and moving in the watersheds, and this should change how we manage ice and snow control,” says Wayne Sandberg, deputy director of the Washington County Department of Public Works. “The next questions are what can we do with that knowledge and what changes can we make.”
- Technical summary: Examining Deicing Chloride Accumulation and Transport Through a Watershed (LRRB/MnDOT, 2017-50TS, Jan. 2018)