Although salt, or sodium chloride, is one of the de-icing tools used to keep roads and sidewalks safe in winter, it leaves a lasting impression.
“Anything that lands on the ground goes into the Lake Superior watershed very, very quickly,” Superior Mayor Jim Paine told participants during a December webinar on reducing salt use at the municipal level.
That includes sodium chloride. From there, it travels along waterways to Lake Superior. That’s where it stays, according to Megan Hogfeldt, water resources specialist with the city of Superior. No natural processes clean chloride out of water, she said. Only reverse osmosis, a desalination process, can do so.
Chloride is considered a permanent pollutant. It only takes 1 teaspoon of salt to pollute five gallons of water to a level that is toxic for freshwater ecosystems, according to the Salt Wise coalition. The group’s mission is to “keep our freshwater fresh,” and that involves smart salting practices.
Salt can be overused. That’s something the groundskeeping staff at the University of Wisconsin-Superior learned during a smart salting training provided by the Minnesota Pollution Control Agency in November.
“After going through it, we realized a few areas where maybe we were over-salting,” said Brayden Ward, unit director for SSC Services for Education, which provides groundskeeping services to the campus. “We’re trying to correct those areas and help with the environment and save some money on our end too.”
SSC crew members use a sand/salt mixture on campus parking lots. There are some sidewalks and entrances where sand or a sand/salt mix can also be used, Ward said, providing traction instead of removing all the ice. The grounds crew is cutting down on quantity, as well.
Ward said hearing the crunch of salt under a person's feet means too much salt has been used.
One 12 oz. coffee cup full of salt is sufficient to de-ice a 70-foot sidewalk, two parking stalls or 320 square feet, Hogfeldt said. If too much salt is applied, the excess could be swept up, dried and reused.
Prevention is also key. Manually clearing walkways and other areas with shovels or plows before snow turns to ice keeps the need for de-icing and salt use to a minimum.
There are alternatives to salt, as well. Sand or sand/salt mixes offer traction with less sodium chloride, although sand can clog storm drains in the spring. Using bird seed for traction serves a dual purpose.
“You can also feed the birds and squirrels,” Hogfeldt said.
A brine mixture of salt and water can be used, both as a pre-treatment before a snow event starts and to help clear the sidewalk of ice after shoveling. Brine breaks down ice quicker than salt, Hogfeldt said, and is effective at lower temperatures.
Since 2014, the city of Superior has been focused on reducing salt use. That has included a focus on plowing and adding a brine truck that uses potassium acetate, which is not technically a salt, to the city’s snow removal arsenal. In the past two years, the city has used 1,000 fewer tons of road salt and saved over $60,000. More important than the cost savings, Paine said, is the impact on the environment.
“We survey the public regularly about what they value about living in Superior,” he said. “When you ask them what they like, what they value, it's always, always Lake Superior.”
Salt Awareness Week kicks off in Wisconsin Monday, Jan. 11. Everyone is invited to visit the Wisconsin Salt Wise website for daily half-hour webinars on ways to reduce salt use. The webinars take place from 12:30-1 p.m. daily on the Wisconsin Salt Wise YouTube channel.
Property owners can also attend a free virtual training session on smart salting practices from 8 a.m. to noon Thursday, Jan. 14.
Visit the coalition's website to learn more about the property manager class and follow the link to registration.