**This blog is part of a sustainability series written by student members of the BSOS Sustainability Task Force. To find out more about the task force, click here.**
Written by: Aaron Bogage
While walking around campus do you often feel the crunch of gravel under your feet? Have you noticed the patches of deteriorated sidewalk throughout campus? Corroding sidewalk is not ideal for the environment, it gets into the streams and pollutes the Chesapeake Bay. This is just one of the negative effects associated with corroding sidewalk due to poor snow and ice removal practices.
What causes the sidewalk to corrode? Turns out it is salt. During winter we dump large amounts of salt to keep ice from forming. This is effective, however, this salt can stick around until summer time. During that length of time it is taking a toll on sidewalks and aquatic life.
Just like the sidewalk pieces, the salt is washed into the Chesapeake Bay. Oysters are largely researched in the bay and their existence is vital to the local community. While increased salinity is ideal for oysters reproduction there is also an increase in diseases. MSX and Dermo are the two main diseases found in the bay that can quickly decrease oyster populations.
While it is not entirely clear how salt damages concrete there are a number of known factors for how salt exposure contributes to the deterioration of concrete. First because salt is mildly acidic it can increase the pore size of the concrete. This allows water to seep into the concrete and over repetitive freeze/ thaw cycles the concrete is broken down. Also salt is hygroscopic which causes it to attract and retain water. The increased absorbed water leaves less room for expansion in the concrete. There then is more pressure in the concrete when it freezes causing it to chip and flake. Corroding sidewalk and associated salt clearly are a problem and it is imperative that the University of Maryland addresses this issue. To do this, the administration needs to reevaluate their current snow and ice removal practices.
What We Currently Do
The University currently uses a pretty typical process to remove snow and ice during the winter season. The main tactic is to remove most of the snow mechanically, with snowplows, tractors, snow blowers, and with University employees shoveling. For the most part, using machines and manual labor to remove snow works pretty well.
Ice on the other hand, is much more difficult to remove, and, as I am sure you have experienced, using the shovels and machines does not always work. For these cases, the University uses different kinds of ice melt materials, and salt to melt the ice. There are three primary kinds of ice melt, sodium chloride, magnesium chloride, and calcium chloride - each one with different effects on the ice and environment.
I spoke with Patrick Rhodes, Assistant to the Assistant Director of Maintenance of the Department of Residential Facilities, and he outlined the ways that the University utilizes the different kinds of ice melt. He mentioned that the University primarily uses two kinds of ice melt for the sidewalks and brick pavers on campus. Calcium chloride is primarily used for the brick portions on campus, while sodium chloride should not be used on brick, and instead is used on sidewalks and concrete. He mentioned that the University strives to keep the products separate, and only use the appropriate material on the correct surfaces in order to keep the environment and campus clear. There are minimal negative effects to the environment if the materials are used correctly. However, research indicates that the commonly used Sodium Chloride salt does in fact cause the problem addressed earlier.
Still, there are more ways we can strive to have more sustainable snow removal.
What we can do
- Eco-friendly ice melt substances as an alternative to rock salt.
Calcium magnesium acetate (CMA) “has less potential to affect the environment and is not as corrosive as salt”. It is made from limestone treated with acetic acid. However, CMA does tend to be more expensive and harder to find.
There are also products like “Ice B’Gone Magic”, advertised as being “safer for plants, people, and pets” and not as corrosive to concrete. It is “de-icing agent made from a patented blend of magnesium chloride and condensed distiller solubles”. Magic Salt claims to work faster and last longer, saving the consumer 30%-50% in salt use.
Another, more DIY option used in Duluth, Minnesota, is to mix brine with salt to reduce salt consumption. In Joliet, Illinois, the city has gone to a 50/50 “mixture of salt and grit on neighborhood streets and began mixing beet juice with its salt piles”. “The mixture has lowered the corrosiveness of the salt, resulting in less damage to streets, parkways, vehicles and receiving waterways. Joliet also pre-wets pavements [with the mixture] before snow and ice storms, which reduces the amount of salt that needs to be applied during a storm.” This also helps keep snow and ice from freezing to pavement.
- Battery, electric, or hybrid-powered snow blowers instead of gasoline-powered ones.
Using these kinds of snow blowers instead of gas guzzling ones can significantly reduce the carbon footprint of snow removal. This is especially important for UMD because so many of the surfaces that need to be cleared are not roads, but the large network of sidewalks.
- Heated floor mats.
UMD wouldn’t economically be able to cover the entire campus with heated floor mats, but in a few strategic locations, like in front of Stamp or McKeldin, heated floor mats on sidewalks (or built into new sidewalks!) could prove energy and economically efficient. One benefit of external heated floor mats is that they are removable! Because of this, UMD wouldn’t need to buy heated floor mats to cover the entire campus; but could have maximum benefits if traded from location to location.
- Make plow routes more efficient.
The city of Duluth, Minnesota has harsh winters, but also an active salt-reduction plan and sustainability objectives. One of their tactics is to calibrate their “plow routes so they can be completed as efficiently as possible, reducing fuel consumption”.
- Create a snow site-engineering plan.
Sustainable snow removal requires careful planning ahead of time. Evaluating trends, working out logistics, and acquiring the right tools should happen months before snow is falling. Long-term planning will help ensure environmental sustainability as well as economic efficiency. A snow site-engineering plan should include priority areas, location of strategic points (e.g., emergency exits, fire hydrants), bulk salt loading and storage areas, on-site snow relocation areas, and no-snow areas. In a built environment as rapidly changing as the UMD campus, a snow site-engineering plan should be updated often.
Aside from getting a day (or week) off from school, Patrick also mentioned that the students are typically very helpful and understanding during these times. He mentioned that it is important for students and faculty to stay away from the equipment, even when it is off, in order to stay out of harm’s way.
Even with all of these different methods of snow and ice removal, it is sometimes not enough. In 2014 there was a petition that reached over 2,000 signatures to cancel school due to the dangerous walking conditions for students. The link below will take you to the petition.
All in all, the University needs to reevaluate their current practices to make the conditions on campus safer for students and the community.