Student Intern Column: Madison Residents Promote Sustainable Road Salting Practices

Brine tracks on Linden Drive in Madison. Photo by Nathan Jandl.
Brine tracks on Linden Drive on the UW-Madison campus. Brine, which is applied by facilities crews, helps reduce the amount of salt necessary to keep the roads safe. Photo by Nathan Jandl.

Norma Behrend-Martinez is a sophomore double majoring in Journalism and Environmental Studies. Brought up on Gene Roddenberry, Norma values differences in ideas and hopes to spread discussion on issues as an environmental journalist. She began interning at the Office of Sustainability in the summer of 2019 as part of the Communications and Green Office teams. During her free time, she can be found analyzing books and movies, jamming to classic rock, and cooking Hispanic food.

In a small blue townhouse in the Marquette neighborhood, the barking of an excited border collie vibrated through the kitchen and into the living room. Moments later, the big black dog jumped onto my lap and gave me a slobbery kiss on the cheek. The dog’s name is Maddie, and her owners, Donna Boucher and Sue Mills, expressed concern over the impacts that road salt had on the 3-year-old dog.

Watching Maddie lick her paws, Mills adjusted her glasses and said, “If there’s a lot of salt, it burns her paws. So, we did get some little booties for her. Especially after it snows and we know people throw them down a lot, we put the booties on.”

Mills took out her phone and showed a video of Maddie struggling to walk in her red booties. If she doesn’t wear them and goes out in the snow, salt could harm the skin of her paws. And if her paws aren’t cleaned afterwards, she could accidentally ingest the salt and develop different issues such as hypertension, vomiting, and seizures, according to WI Salt Wise.

Graphic explaining the effects of salt contamination on local watersheds. Courtesy of Wisconsin Salt Wise.
Graphic explaining the effects of salt contamination on local watersheds. Courtesy of Wisconsin Salt Wise.

WI Salt Wise, an informal partnership between the Madison Metropolitan Sewerage District (MMSD) and other stakeholders of Madison’s watershed, was created in 2014. MMSD had noticed high concentrations of chloride, which is a component of salt, in its wastewater.

Salt has also been on the rise elsewhere in Madison. Wells 14, 16, 6, 15 and 23 of the City of Madison have seen a rise in chloride levels; so too has Lake Wingra, whose small size and urbanized watershed causes it to have higher concentrations of chloride compared with the other lakes in the Madison chain.

Chloride does not biodegrade and removing it from water is a costly ordeal. It would cost between $400 million and $2.3 billion for  MMSD to install equipment to remove chloride, according to Pollution Prevention manager Kathy Lake. The process would also require major energy usage.  “In order to remove just the salt from … our wastewater,” Lake added, “[it] would take more energy than we use to run the entire plant.”

Research matters

Tristyn Forget, a second-year graduate student at UW-Madison, is a part of the Nelson Institute’s Water Resources Management cohort. The group of graduate students has been working for about two years to create a blueprint to reduce UW-Madison’s salt use. Forget said her team found that 50% of UW-Madison’s salt use came from road salting, while the other 50% was found in water softeners.

Each of these sources can be partially mitigated. According to a MMSD study, upgrading water softeners to newer models could improve their efficiency by 27% as well as reduce chloride usage by 50%.

Meanwhile, alternatives also exist for road salt. Boucher and Mills prefer to use sand, not only because it saves their dog’s paws, but because it does not have a freezing point. Road salt, on the other hand, is ineffective under 15° F.

Boucher has also seen neighbors in Marquette re-using kitty litter in place of salt or sand on their sidewalks. Magnesium Chloride or Calcium Chloride are also superior to normal salt, since they do not decrease the permeability of soil, according to the Minnesota Stormwater Manual.

Preparing for snow

In Wisconsin, winter storms are not uncommon, so how should residents prevent slippery, dangerous surfaces? While the City of Madison is doing a good job pre-treating roads, Madison residents and businesses are responsible for sidewalks, driveways and parking lots.

Graphic demonstrating the amount of salt for roads, driveways, and sidewalks. Courtesy of Wisconsin Salt Wise.
Graphic demonstrating the amount of salt for roads, driveways, and sidewalks. Courtesy of Wisconsin Salt Wise.

Placing salt on snow does nothing, but pre-treating with a salt brine before a storm hits can be very beneficial. “When you do use [brine] correctly, it does reduce the amount of salt that you use by 20 to 30%,” Forget commented. Still, the biggest thing residents can do, according to Boucher, Mills, Forget, and Lake, is to shovel right after the storm. Then, if a resident is using salt rather than sand, scattering it lightly works better than throwing piles on the ground.

Since the WI Salt Wise program started, the spread of sustainable road salting is changing Madison residents’ attitudes towards salting. “Other sources of chloride are decreasing, too, but we have to stay vigilant,” Lake said. “While chloride mass has been decreasing from existing sources, we also have a lot of new construction. Each time a new water softener is added, it adds more chloride to the wastewater – which ultimately ends up in a freshwater stream.”