On The Road to Less Salt Use in Minnesota Cities

By Connie Fortin

Minnesotans are all too familiar with below-zero temperatures and the early morning shovel and salt routine. When cold weather encompasses our state, we manage snow and ice with plows, shovels, snow blowers, and tons of salt.

Salt, a commonly used deicer, is viewed as a helpful companion to soften our water and clear our roads of snow and ice. In fact, Minnesota taxpayers spend more than 100 million dollars each year purchasing salt for city, county, and state roads. Unfortunately, salt also has a downside.

Rock salt, also known as sodium chloride, is used in various applications statewide. It then runs off into our lakes and streams — endangering our freshwater fish and other aquatic life — and seeps into our groundwater that supplies our drinking water.

Winter training today

For Minnesota, the land of 10,000 lakes and with more miles of shoreline than California, Florida, and Hawaii combined, it’s no surprise that there is a massive statewide effort to reduce salt use. Minnesota is at the forefront of the nation for providing educational opportunities related to lower-salt winter maintenance technologies, strategies, and tools for winter maintenance pros, from private operations through every level of government.

But even when winter maintenance operations are at the top of their game, the chloride problem will still be growing, albeit at a much slower rate. To maintain Minnesota residents’ comfort and safety and the health of our environment for current and for future generations, something needs to be done about salt usage.

Reducing salt use through infrastructure design

It is time to challenge our engineers to enhance winter performance by designing infrastructure with low salt use in mind. As engineers are challenged to do more with less, complaints are often heard about infrastructure not being designed for winter maintenance. By presenting this insight to design teams, engineering standards can be enhanced to provide better performance during the frozen months of the year.

All potentially salted infrastructure can benefit from winter design criteria. Through redesign, nature can be used to our advantage by capitalizing on the sun’s energy to melt critical ice patches, and better managing the prevailing winter winds to prevent drifting snow.

Another method to enhance infrastructure design is focused on reducing the meltwater footprint, which also reduces the need for salt. Every thaw-and-freeze cycle (meltwater) creates a salting event. By directing meltwater away from braking/ stopping zones and high pedestrian areas to mitigate refreezing, the need for salt is reduced and safety is improved.

Refocus on tackling snow

Why has winter been partially overlooked in our snowy state? Perhaps it is because the emphasis, requirements, and expectations placed on engineers are centered around handling the volume, rate, and routing of stormwater.

These elusive elements of winter are not more complicated than summer stormwater management but are often forgotten or given lower priority. Rain is handled when it falls from the sky, but the same snow is handled multiple times, as it blows, drifts, melts, runs, and refreezes, creating multiple salting events for the same snow. Our stormwater ponds and rain gardens perform well in the summer, but the salt from snow and winter meltwater impair the function of these stormwater management strategies.

High performance should be designed for all four seasons by using snow gardens, areas designated for snow storage that help reduce meltwater sprawl, improve safety, and reduce salt use. The first snow garden prototypes were installed in a Greater Minnesota school district, where an annual average of 46 thaw/meltwater sprawl/freeze events are experienced. By changing from a three- to a four-season solution in sustainable thinking, engineers can provide more cost efficient and higher performing infrastructure.

Designing for winter and a better future

Engineers, architects, and planners should work to provide sustainable winter infrastructure solutions. Following are five, winter low-salt design principles to consider when working on an infrastructure project:

• Keep angle of the sun in mind to ensure it reaches and melts critical icy patches.
• Consider direction of prevailing winter wind to prevent drifting snow and blow.
• Consider directional flow of meltwater and mitigate refreezing across roads, parking lots, etc.
• Ensure proper salt storage to prevent runoff.
• Consider pavement alternatives such as permeable pavements, which drain meltwater more efficiently and require less salt.

There is no place better than in the frozen north to address low-salt winter design. The freshwater future is calling!

Connie Fortin is a water resources senior project manager with Bolton & Menk (bolton-menk.com). Bolton & Menk is a member of the League’s Business Leadership Council (lmc.org/sponsors).