“We’ve reduced our winter salt use from 1200 pounds per year to 800,” says Shawn Sanders, Public Works Director for the City of Stillwater. In Forest Lake, Dave Adams shares a similar story, “We’ve reduced our winter salt use and are currently only treating intersections.”
Communities across the Twin Cities are currently waging a battle against time, as they work to curb the flow of salt into lakes, rivers, streams and groundwater before it’s too late. Currently, 54 lakes and streams in Minnesota are listed as impaired due to excess chloride (salt) and the MPCA plans to add an additional 13 water bodies to the list in 2024. Frighteningly, an additional 120 water bodies are tottering near the threshold for chloride impairment and could be added to the list in the next five years if salt use in their surrounding watersheds isn’t dramatically reduced.
Most people understand that chloride is toxic to freshwater animals such as fish, aquatic bugs, mussels, and amphibians. In addition, high chloride levels can also disrupt natural processes in aquatic ecosystems, leading to more cyanobacteria, increased internal nutrient loading, more frequent anoxic conditions, and mobilization of radon, mercury, and lead. Unlike phosphorus and sediment, chloride is considered a permanent pollutant because there is no practical way to remove it from surface and groundwater resources once it is there.
In Washington County, almost every community has sent their staff to SMART Salt certification programs run by the Minnesota Pollution Control Agency (MPCA), and many have purchased specialized plow equipment with pavement temperature sensors and weather prediction software to help their staff reduce salt use without compromising public safety. Even so, more action is needed.
One major challenge is how to reduce the amount of winter salt applied by private contractors and property owners. Changing public expectations and behavior can be a hurdle as well. Property owners often over-apply salt to parking lots and sidewalks to avoid the risk of slip-and-fall lawsuits, even though more salt doesn’t necessarily translate into safer conditions for walking and driving.
Connie Fortin of Bolton & Menk helped to develop Minnesota’s SMART Salt training program and has been a thought-leader on the issue of chloride pollution for nearly two decades. “It’s time for cities to think creatively and take the next steps beyond staff training,” she says. “I talk to them about low-salt design strategies. We’ve spent a lot of time thinking about how to manage stormwater runoff in the summer, but it’s winter half of the year.” Some of Fortin’s recommendations include siting parking lots in the sun instead of the shade so that ice is less likely to form, thinking about the best place to store snow piles to prevent meltwater from refreezing on parking lots and sidewalks, and planting trees to create natural snow fences along the edges of roads and parking lots.
At the state level, local government and concerned citizens are requesting new legislation to incentivize SMART Salt training and reduce the liability for businesses and landowners that are implementing best practices.
A final, intriguing, long-term solution comes from Holland, Michigan, where the city uses heated water from a nearby power plant to melt snow and ice on sidewalks and streets in its downtown historic district. The snowmelt system pumps hot water through 168 miles of tubing coiled beneath the pavement and is designed to melt an inch of snow per hour at 20°F, with 10 mph winds. The price tag is substantial – $8 million to install and $20k-$80k per year to operate – but the city has seen cost savings due to less wear and tear on roads and sidewalks and less need for salting and plowing.
As a community resident, you can help to protect Minnesota’s water from chloride pollution with a few simple changes. At your home, always shovel before applying salt and only use sodium chloride if the pavement is warmer than 15°F. One 12-oz coffee cup full of salt is enough to melt 10 sidewalk squares or a typical 20-ft driveway. Be cautious as well with deicers labeled “eco-friendly” or “pet-friendly” – if there is chloride in the product, it is still a salt. Finally, be a good citizen and a hardy Minnesotan. Put on a pair of boots, drive slow, and thank your city plow crews for working to keep us safe.
East Metro Water 