In cold, snowy climates, winter road safety is an ever present concern. Our most common tool to reduce icy conditions is the use of salt applied to the road surface to lower the freezing point of the water and improve traction for cars and trucks. Salt is very effective at this job.
Unfortunately, salt is used in such high volumes and often without regard to sensitive adjacent ecosystems that we are now measuring widespread salinization of freshwater resources. Watershed is involved in long term, year round data collection efforts of chloride levels in streams, rivers, wetlands, and soils to deepen our understanding of impacts locally. The news is concerning, but similar to reports from elsewhere in the country:
- A spike in stream chloride concentration is noted during winter thaw periods – routinely above standards for chronic (230 mg/L) and acute (860 mg/L) toxicity to aquatic organisms
- Spring melt and later summer storms can result in further chloride spikes, from a lag in release likely from temporary storage of the ions in roadside and wetland soils and pore water
- Once in the receiving water body, chloride cannot be removed. The only solution to improving conditions is reducing loading from the source.
Not satisfied with simply identifying the extent of the problem and knowing the elimination of salt as a method to control ice is currently impractical, we are actively engaged in developing technologies to reduce the movement of chloride to waterways and are seeking partners to trial some solution designs on the ground. Please reach out to our Water Quality Program Manager if you are interested to learn more.