Despite lingering cold temperatures, winter 2020-21 was warmer and less snowy than a standard northern Michigan winter. That milder weather helped the City of Traverse City and Grand Traverse County reduce road salt usage significantly – good news for everything from municipal budgets to the environment. But while both the city and county are working to minimize road salt usage more permanently, critics suggest that salting roads in northern Michigan has already had dire consequences for local bridges, roads, and watersheds – and that finding a way to eliminate salt usage entirely might be necessary to preserve infrastructure and protect environmental health.
Salt is used on roadways in the winter because it lowers the freezing point of water, thus preventing ice from forming as temperatures dip below 32 degrees. It’s highly effective at keeping roads safer for drivers — but it’s also highly corrosive and can cause spalling and scaling to concrete and other surfaces.
Over the past several years, local photographer John Robert Williams has used a photo series to document the destructive effects of salt, particularly to Traverse City bridges. Williams tells The Ticker he was inspired to track the issue in part because of his father, who worked at Dow Chemical.
“His job was to sell Dow deicers to the road commissions in the State of Michigan,” Williams recalls. “And the whole reason that Dow Chemical got its start was, before refrigeration, people used salt to cure and preserve their meats. But as scientists do, they find different applications for things. And so they perfected this whole business about making salt for reducing the ice on roads. But as the engineers and the scientists and the chemical engineers told my dad – and he repeated this to me when I was a little kid: ‘When they find out what this stuff does, there’ll be hell to pay.’”
Williams says it’s easy to observe “the ravages of salt” in Traverse City, from corroded metal bridge railings to pothole-ridden streets to browned and dead pine trees along local roads. He points to the West Front Street Bridge (pictured) as a good snapshot of what salt can do to infrastructure over time.
“And when you get underneath the bridge, you can see the concrete spalling underneath that arch,” he says. “It’s just amazing how much of that bridge is gone, just from salt being poured on it.”
Salt spalling occurs when dissolved salt flows into porous building materials (such as concrete) or into existing crevices in surfaces and then crystallizes as the surface dries and the water evaporates. As the salt expands, it puts stress on the material, causing flakes (or “spall”) to break away from the surface.
Salt can also pose a risk to local rivers and lakes – something the Watershed Center Grand Traverse Bay monitors actively. According to Heather Smith, Grand Traverse Baykeeper for the Watershed Center, road salts that make their way into…