Liza Mclatchy ’23 carefully reaches into the water with a long sampling rod—at its end is a plastic collection bottle. Her research partner Evelyn Densmore ’23  is standing a few feet away and making recordings into a logbook. Within the next 24 hours they will analyze the water samples in UVM’s Environmental Engineering Teaching Lab.

They are standing at the edge of a retention pond on the east side of campus. This will never be a beach destination, especially in early March when the surface water is still frozen. The students are investigating salt levels in the water and this pond, the Main Street Stormwater Treatment Facility East, collects runoff from parking lots on the UVM Medical Center campus. It is one of 11 containment ponds scattered across the 460-acre UVM campus.

“Eventually water from this pond flows into Centennial Brook,” says Mclatchy “And that flows into the Winooski River and ultimately Lake Champlain.”

Students have been working for the past nine months to collect and analyze samples from five of UVM’s containment ponds. The data they collect will serve as a baseline for an ambitious project aimed at reducing salt use on campus.

That makes Mclatchy and Densmore essential members of the Salt Mitigation Task Force, a group of faculty, staff and students formed last January.

“Making sure pedestrians on campus are safe while being cognizant about environmental damage salt causes is a delicate balance,” said Lynn Wood ’20, physical plant facilities manager at UVM.

Cost was another big catalyst leading to an institution-wide effort to reduce salt use, she says.

“Our rough estimate is that we’ve spent $1.7 million in unscheduled maintenance due to salt damage over the past five years. That’s a big bite out of our maintenance budgets.”

The Problem with Salt

Application of road salt, even on newer infrastructure on campus, can cause steel doors and frames to rust prematurely, concrete sidewalks and stairs to crack, and mortar in brick and stone structures to corrode.

And that’s just the above ground infrastructure. Salt also can eat away at underground utility vaults, concrete chambers that house valves and other key components that deliver steam to campus buildings. Kevin Sweeney, UVM’s deferred maintenance project manager, has the tricky job of keeping systems running while repairing vault damage.

He noted that rebuilding and waterproofing a utility vault near the University Heights complex recently cost $167,000. “We ended up increasing the elevation of the vault and bringing the vents above grade so runoff into vault wouldn’t be an issue,” Sweeney said.

As any UVM chemistry student can tell you, salt and concrete just don’t mix. Calcium hydroxide present in concrete reacts with the calcium chloride in salt, creating calcium oxychloride. When forming inside concrete, calcium oxychloride crystals expand, causing internal cracks and crumbling.

Still, salt is a natural solution for preventing accidents in wintery weather. Salt lowers the freezing temperature of water, preventing ice from forming. The problem is that salt not only damages buildings but contaminates drinking water, kills plants, reduces soil permeability and damages freshwater ecosystems.

Associate professor Kristine Stepenuck, extension program leader for Lake Champlain Sea Grant, has dedicated her career to understanding human impacts on freshwater resources. She’s explored the history of using salt as a melting agent since the early 1940s when salt was first used by the New Hampshire Department of Transportation.

“At that time about 5000 tons of salt were used per year in U.S.,” she said. “Fast forward to 2015, about 20 million metric tons of salt were used each year.”

How much is that? Stepenuck provides this illustration: “If each salt truck holds 10 tons of salt, 120 million metric tons would create a traffic jam of salt trucks from Burlington to Seattle, back to Burlington, and back again as far as Glacier National Park.”

Professionals charged with applying salt where it is needed at UVM have continued to introduce new materials and methods to reduce usage. Matt Walker, grounds manager for the physical plant department, uses magnesium chloride, an anti-icing liquid which helps break the molecular bond between ice and paved surfaces and makes cleanup more efficient. The department had previously used rock salt for this purpose.

But as the climate warms, Walker and his colleagues face an uphill battle.

“Ice events are occurring more frequently in recent years,” he says.

It’s also another expense: the university spends about $200,000 on salt each year.

Salt Talks

Funding for the task force’s work comes from UVM’s Sustainable Campus Fund (SCF), which supports proposals aimed at improving campus sustainability. The SCF is funded through a $10 per semester student fee, so projects are essentially supported by the entire student body.

Courtney Giles, lecturer in civil and environmental engineering and director of Curricular Enrichment in CEMS, wrote the successful proposal last year that garnered $40500 in funding for task force activity.

The task force represents an in-house “dream team” including staff, faculty, researchers and students.

“We have a lot of talented and knowledgeable people right here on campus. Bringing together materials scientists as well as the people who maintain our infrastructure gives us a really data-driven interdisciplinary approach,” Lynn Wood said.

The SCF grant also funded the purchase of new equipment and technology with potential to reduce salt consumption. A new Hilltip truck mounted combined spreader is already in action this winter. It can distribute both a liquid de-icing agent and rock salt on walkways. Spreading of either product is pre-programmed using geo-tracking software. “It helps take a lot of the guesswork out of the equation,” Walker said.

CEMS senior lecturer John Lens led a student project last year in conjunction with physical plant employees. An undergraduate intern in the civil and environmental engineering program documented salt damage to exposed steel and concrete structures across campus. Lens and Giles are also planning on detailed chemical analyses of de-icing salts used on campus to identify specific trace constituents potentially more harmful to infrastructure and the environment.

“Ultimately the material engineering aspects of our work will hopefully lead to design recommendations for new structures we build,” Lens said.

Final Phase

With SCF funding, the task force can coordinate their efforts on a consistent campus-wide scale. The group has been meeting monthly since January of 2021.

One of the first goals the group established was finding ways to measure results over time. That’s where students come in.

Through an REU (Research Experience for Undergraduates), environmental engineering majors Robby Tschiember ’22 and Mclatchy began taking water samples last summer, when the presence of salt, as indicated by specific conductance and measured in microsiemens per centimeter, were expected to be relatively low. 

They are still in the data collection phase, but their lab analyses show, as expected, much higher salt levels as winter progresses.

Tschiember is gratified that the work he’s doing is more than just an academic exercise. “It’s great to be able to do this along with faculty advisors who are showing me the ropes of how research works and how it can have real outcomes.”

Likewise, Mclatchy knows the work she’s doing will result in real-world benefits.

“I know the work I’m doing is going to make an impact on the Burlington community. It makes me feel like it’s part of something bigger than me. It’s not just a job—it’s way more than that.”