Illustration by Tabitha Walters
It was a snowy winter, and Ann Arbor used a lot of road salt to clear its streets: 4,057 tons as of March 19, according to city communications specialist Robert Kellar. That’s 656 tons more than last winter, though still around 1,800 tons shy of the most recent high in the winter of 2021–2022. Along with ice-melter applied by contractors and homeowners, some of it ends up in storm sewers and the Huron River tributaries they feed.
Huron River Watershed Council water quality specialist Kelly McCabe says that Malletts Creek, Millers Creek, and Swift Run all have average chloride concentrations of 300 to 500 milligrams per liter; Honey, Traver, and Allen creeks also have higher-than-healthy levels. She adds that the Huron itself, the source of most of Ann Arbor’s drinking water, has “acceptable chloride levels.”
McCabe says HRWC’s observations indicate that salt has “built up in the groundwater, likely over time, and then is replenished in the winter months.”
“There is potential that aquatic life is being affected” in those urban tributaries, she says, though other stressors make it difficult to pinpoint the exact impact. And while she calls road salt “the major one,” there are other potential chloride contributors: fertilizers, detergents, water softeners, human and animal waste, even natural geological and weathering processes.
“The City follows industry best practices to achieve a balance between traffic safety and environmental impacts,” emails Kellar: investing in plows that clear more of the street, spreaders that distribute salt more efficiently, and staff training. To keep ice from forming, roads are pretreated with a salt brine made with better-for-the-environment calcium chloride and beet juice. Plows remove snow and slush before spreading pre-wetted salt—it sticks better—and environmentally sensitive areas receive a salt-sand mixture.
Related: Plowing the Neighborhoods
Crash
The Michigan Department of Transportation clears I-94, M-14, and US-23. MDOT media rep Aaron Jenkins says they also aim to use salt efficiently, but statewide salt use was up “about 30 percent” this winter from its average of 450,000 tons.
The only way to fully remove salt from waterways would be to stop using it and wait for it to eventually flush out. The next best thing is reducing salt use. People can help when clearing their own driveways and sidewalks.
The most environmentally friendly way to remove snow and ice is with a shovel; for any ice that remains, the Salt Smart Collaborative advises that a twelve-ounce coffee mug of salt, spread evenly, is enough to deice ten sidewalk squares.
