The 2020 Nelson Institute Water Resources Management Cohort presented their findings Wednesday from their study on University of Wisconsin salt usage and made recommendations to make winter salting and water softeners more sustainable.

The study is a part of a masters program through the Nelson Institute. The members of the cohort partner with Madison Metropolitan Sewerage Department and were tasked with assessing UW’s salt usage and finding ways to lower the campus’s overall usage by 25%.

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The cohort monitored chloride levels (chloride is a common water toxin from salt) in bodies of water located on campus. They also analyzed data collected from past studies to gauge which areas experienced chloride toxicity. Cohort member Michael Webber said a body of water has chronically toxic levels of chloride when it reaches 230 mg/L of chloride and acutely toxic levels when it surpasses 757 mg/L.

“At the acute level, adverse effects and even mortality have been observed in some small freshwater species,” Webber said. “More saline waters also benefit invasive species. While native species are adapted to freshwater environment, many invasives, like the zebra mussel, are adapted to more brackish environments.”

The cohort also collected data from campus facilities on the amount of salt used in water softeners and during winter street salting. Cohort member Lydia Salus said the total amount of salt used by the university in 2018 was 1,708 tons.

Salus said this is an underestimate because not all salt usage was reported. Additionally, salt usage fluctuates each year because of demand and temperature, Salus said.

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“1,708 tons of salt is enough to fill 60% of Camp Randall,” Salus said. 

To reduce salt usage on campus, the group recommended creating a standard salting policy for all of campus, replacing outdated equipment, expanding data collection and increasing campus-wide awareness for why limiting salt is necessary.

Cohort member Wei Tang said another strategy to incorporate salt sustainability into campus curriculum could be encouraging chemistry courses to measure salt content in water and art classes to create salt awareness posters. 

Cohort member Abigail Ernst said more salt does not mean less ice because salt becomes less effective as temperatures drop. Cohort member Tristyn Forget said the cohort acknowledges that winter salting is important for public safety.

“It’s important the university work to become a more salt sustainable campus,” Forget said. “We would like to clarify that by salt sustainable, we are not recommending the university stop using salt. The key is finding a balance between safety and sustainability.”