Designing a Lower Salt Future: Examining Chloride’s Environmental and Infrastructure Impacts
The following article is a peer-reviewed accepted manuscript submitted to the Journal of Soil and Water Conservation. You can read the final published work through Taylor & Francis Online. Note: you must either be a Taylor & Francis Online subscriber to view the full article, or you can view purchase options for full article access.
Connie Fortin1, and Carolyn Dindorf2
1Water Resources Senior Project Manager, Bolton & Menk, Inc., 3300 Fernbrook Ln North, Suite 300, Plymouth, MN, 55447-5324; email: [email protected] (Corresponding author)
2Water Resources Limnologist, Bolton & Menk, Inc., 3300 Fernbrook Ln North, Suite 300, Plymouth, MN, 55447-5324; email: [email protected]
INTRODUCTION:
In preparation for winter in cold weather places, plows are tuned up and salt is stockpiled. What could be wrong with that? After all, preparation is a good thing, isn’t it? Not when you’re talking about excess salt!
The most commonly used deicer is rock salt (sodium chloride). Rock salt is selected for many reasons: it is inexpensive, it works well, it has been used for the last 50 years, and we are comfortable with it. Most people do not think of salt as dangerous (after all, we eat it) and subsequently do not know of the enormous backend costs we pay for using it.
Once salt is applied, the chloride component of salt travels from the road or sidewalk into water sources. It may infiltrate through the soil into groundwater, run across the land, or flow into a pipe to surface water. It is invisible as it dissolves and moves through the environment, and it typically is not given a second thought—but it should.
Chloride’s Impacts on Water and Soil
Chloride is used in many industries and found in a variety of products such as road salt, water softening salt, dust suppressants, and fertilizer. For stormwater management, deicing salt is the primary method. To minimize chloride’s impact, source reduction is the answer.
In the US, the United States Environmental Protection Agency (USEPA) sets water quality standards for a variety of pollutants, including chloride, which is currently a top pollutant of concern in Minnesota. According to the USEPA, chloride is toxic to aquatic life at 230 mg/l (federal chronic standard). Salt can damage fish eggs and small organisms in freshwater. Just one teaspoon of salt pollutes five gallons of water to the 230 mg/l threshold.
In addition to water contamination, the sodium in deicer salt affects soil structure. It works like a water softener in which sodium ions displace calcium and magnesium ions, weakening the soil’s integrity. This can increase erosion potential, reduce infiltration, and decrease plant viability on roadsides.
In addition to the environmental impacts of chloride, there are also significant infrastructure impacts. According to the Minnesota Pollution Control Agency (MPCA), infrastructure damages from deicer salt range from US $1,700 to US $17,000 per ton (Minnesota Pollution Control Agency, 2023a). Local governments might have funds to load the plow trucks with salt and apply it, but can they bear the cost of fixing crumbling bridges, building foundations, and roadways as well as cleaning contaminated water?
Chloride is a permanent pollutant; it never biodegrades or breaks down. Removing chloride from water is very difficult, expensive, and energy intensive. Even if it is removed through processes like reverse osmosis, chloride remains in waste streams.
Creating a Chloride Management Plan
The first step in reducing chloride sources is to identify the sources in your area of concern and develop a chloride management plan to address each source. The area may be a watershed, city or county, river or lake, including regions where environmental stewardship is a priority. Minnesota has a statewide chloride management plan (Minnesota Pollution Control Agency, 2023b). Salt is Minnesota’s largest source of chloride, followed by fertilizer and wastewater treatment plants (with major contributions from water softening and industrial sources; Figure 1). In other cold-climate states in the United States, within developed areas, road salt is likely the number one source as well. Fertilizer or wastewater treatment plants may be larger sources in rural areas, with livestock waste and dust control also contributing significantly.
A chloride management plan should identify sources, categorize the users and the reasons they use salt, and formulate salt reduction strategies. Typical users may be winter maintenance professionals, farmers, or water softener users. Typical reasons for salt use may be icy roads, hard water, a need for potassium in fertilizer, dusty roads, fear of lawsuits if someone slipped on one’s property, and so on. For some sources of chloride, such as agricultural fertilizers that use potassium chloride, there are limited practices for reducing chloride, or the costs for non-chloride alternatives prevent their use. Example reduction strategies may include shifting from granular to liquid deicers, designing highway ramps so that snow will not melt across them, using more salt efficient water softeners, following potassium recommendations based on soil tests, and using non-chloride dust suppressants.
Chloride management plans range from simple to complex. A simple plan may only identify sources, users, and reasons for salt use and offer reduction strategies. A more rigorous plan might include modeling these chloride sources to better understand how they impact a water source of concern. The Minnesota Pollution Control Agency (MPCA) Smart Salting Tool, initially created by Connie Fortin and her former company in collaboration with the MPCA and now managed by Bolton & Menk staff, assists governmental and private organizations in identifying chloride sources and best management practices for salt reduction (MPCA Smart Salting, 2025). The tool is free for anyone to use and relies on default values for chloride sources, which can be improved with local data. In addition, incorporating an education and outreach component into your plan will help chloride users understand the problem and the need for chloride reduction.
Implementation of the plan includes steps that each contributor can take to reduce chloride use. The plan could include strategies for preventing the need for salt in the first place, such as designing infrastructure for superior winter performance.
Finally, observe the plan’s progress by establishing a long-term monitoring program to track chloride changes in impacted waters, such as lakes, streams, wetlands, and groundwater, as well as wastewater treatment facilities’ discharge and stormwater ponds. Ask or require large salt users to track their salt use and provide you with that data. Don’t expect to see chloride reductions in the water quickly. It likely will take many years to see noticeable changes, but it will increase without intervention.
The next section offers some examples of chloride reduction strategies related to winter maintenance practices, followed by a simple but innovative set of low salt design strategies to minimize the need for salt.
Salt Reduction Efforts in the Winter Maintenance Industry
As previously mentioned, deicers are a primary area of concern as a chloride source. Winter maintenance professionals are trained to keep road and sidewalk surfaces safe in winter but may be uninformed on the long-term dangers of salt. There is still a need within this industry for education on the environmental impacts of salt use and an industry shift toward more precision and salt efficient maintenance practices. Precision practices would include staff training, high-performance and calibrated equipment, and improved mechanical snow and ice removal. Other practices include selecting appropriate granular and liquid materials for pavement conditions; following best practices for timing, plowing, and applying deicers; and leveraging science and technology to achieve pavement recovery at a lower salt cost.
Dindorf and Fortin, with the funding support of the MPCA and local watershed organizations as well as the support of local technical advisors, created training materials and conducted training on best management practices for winter maintenance professionals in Minnesota. The success of their MPCA Smart Salting program has informed other states’ development of low salt winter maintenance training: the Wisconsin Salt Wise program (Wisconsin Salt Wise, 2025), the Illinois Smart Salt Collaborative (Salt Smart Collaborative, 2025), and the New Hampshire Green SnowPro program (New Hampshire Department of Environmental Services, 2025). Clear Roads is a research hub funded by Department of Transportation (DOT) organizations in cold-climate states that offers insight into the growing desire to move winter maintenance toward a precision industry (Clear Roads, 2025). Winter maintenance training and chloride awareness are recommended for all who deal with winter—from policymakers, homeowners, and private contractors to city, county, and state maintenance workers.
In their decades of training public and private winter maintenance professionals through the MPCA Smart Salting program, Dindorf and Fortin noticed a common complaint about our built world regarding infrastructure in winter. Program participants frequently asked, “Who is designing these roads and parking lots, and why don’t they think more about winter?” Winter maintenance professionals cited common problem areas such as ice patches under bridges, clover leaf that forms a sheet of ice, the contour of an accessibility ramp that is too narrow for their plow blades, snow that continually drifts across front steps, and roof snowmelt that drains onto sidewalks and forms ice patches overnight.
To get at the root of the salt problem—better design to reduce the need for salt—Dindorf and Fortin approached Bolton & Menk. A multidisciplinary engineering firm, Bolton & Menk designs all types of surfaces used in day-to-day life that get salted: bridges, roads, parking lots, sidewalks, trails, and more. Once the vision for designing better performing winter infrastructure had support to train civil engineers, the company created an in-house low salt design initiative to give winter a bigger seat at the design table.
Fortin reminds designers that the plow driver’s job is to remove the snow that falls from the sky from saltable surfaces, whereas the civil engineer’s job is to not let snow get back onto those saltable surfaces. This idea is something they may not have considered before this initiative. For more insights on innovative approaches to salt reduction, listen to the River of Ideas Podcast (River of Ideas Podcast, 2025).
Great Things Happen When We Design for Winter
If we design for winter, we can speed up pavement recovery and reduce the repeat offenders of blowing snow and meltwater sprawl. Many areas of the United States are experiencing more meltwater events than in past years. Managing the meltwater sprawl, which reduces the refreeze area, is a climate action plan to improve winter safety.
Why haven’t we been designing for winter? Typically, engineers do not have design checklists or performance criteria established for the winter performance of a road or site, unlike performance criteria used for managing the effects of rain on infrastructure. Snowmelt volume and rate typically fall within the parameters we use to design for rain, leaving other snow issues largely disregarded.
In the Low Salt Design initiative, we identified several categories of thought (Figure 2):
- Drainage (horizontal and vertical): Understand snow placement and anticipate meltwater sprawl (Figure 3) to minimize the footprint of saltable surfaces.
- Plow access: Ensure easy plowing by avoiding obstacles, as more snow left on surfaces requires additional salt for safety.
- Salt storage: Designate and manage temporary or seasonal salt storage to control environmental risks, storing salt at higher elevations than adjacent snow.
- Snow storage: Ensure adequate snow storage space and control meltwater spread, avoiding obstacles like trees, benches, and bushes in storage zones.
- Use the sun: Place critical high-traffic areas (e.g., front steps, braking zones, crosswalks) in sunny spots for faster winter recovery and better returns on investment.
- Vegetation: Landscape architects and maintenance crews can improve winter performance by selecting vegetation compatible with snow storage areas, considering tree placement, and using deciduous species to allow winter sunlight to reach critical areas.
- Outsmart the wind: Understand winter wind angles and implement measures to intercept wind-blown snow before it reaches your site.
Pavement alternatives and reduction: If simple, inexpensive options don’t work, consider pavement alternatives that minimize hard surfaces to reduce ice and salt usage.
Taking Action
We have outlined the chloride problem, encouraged you to identify the chloride sources in your area, and provided examples of strategies to reduce salt usage, such as progressive winter maintenance and low salt design. While our focus has been on reducing the use of deicing salts, we are also raising awareness and promoting salt-saving strategies for fertilizers, dust suppressants, and water softeners, all of which affect our surface and groundwater.
We encourage you to integrate chloride pollution solutions into your work alongside conservation efforts around nutrients and sediment. Since chloride pollution is permanent, the most cost-effective approach is to focus on source reduction. As the leaders in conservation, we have confidence that you will lead us toward a lower salt future.
You can join in on the lower salt conversations virtually at the 26th Annual Salt Symposium on Tuesday, August 5th.
DATA AVAILABILITY STATEMENT:
No data, models, or code were generated or used during the study (e.g., opinion or dataless paper).
FUNDING DETAILS:
No funding was received.
DISCLOSURE OF INTEREST:
The authors report there are no competing interests to declare.
REFERENCES:
Clear Roads. (2025). Clear Roads Research Hub. Retrieved from https://www.clearroads.org/
Minnesota Pollution Control Agency. (2023a). Chloride and water quality. Retrieved from https://www.pca.state.mn.us/sites/default/files/p-tr1-13.pdf
Minnesota Pollution Control Agency. (2023b). Statewide Chloride Management Plan. Retrieved from https://www.pca.state.mn.us/sites/default/files/wq-s1-94.pdf
MPCA Smart Salting. (2025). Smart Salting Training. Retrieved from https://www.pca.state.mn.us/business-with-us/smart-salting-training
New Hampshire Department of Environmental Services. (2025). Municipal Green SnowPro Certification. Retrieved from https://www.des.nh.gov/land/roads/road-salt-reduction/municipal-green-snowpro-certification
Overbo, A., Heger, S., & Gulliver, J. (2021). Evaluation of chloride contributions from major point and nonpoint sources in a northern U.S. state. Science of The Total Environment, 764, 144179. https://doi.org/10.1016/j.scitotenv.2020.144179
River of Ideas Podcast. (2025). Designing for a Low-Salt Future with Connie Fortin. Mississippi Watershed Management Organization. Retrieved from https://www.youtube.com/watch?v=OHsYCMN2qlw
Salt Smart Collaborative. (2025). Illinois Smart Salt Collaborative Overview. Retrieved from https://saltsmart.org/overview/
Wisconsin Salt Wise. (2025). Wisconsin Salt Wise Program. Retrieved from https://www.wisaltwise.com/
AUTHOR LINKS & BIOS:
Connie Fortin has been working for 20 years with winter maintenance professionals trying to reduce salt by integrating science into winter maintenance. Now she finds herself in an engineering firm, Bolton & Menk, working to integrate low salt concepts into infrastructure design. Improved winter design is the most cost-effective way to get on top of the chloride problem and she is energized to share this new strategy.
The limnologist on the Bolton & Menk team, Carolyn began her professional career in 1986. Her love for the natural environment can be encapsulated with her expertise in chlorides, aquatic invasive species, shoreline restoration, and research and education pertaining to reducing impacts of winter and turfgrass maintenance. Carolyn’s work revolves around protecting and improving water resources—contributing her extensive knowledge to environmental projects to reduce risks to the environment and its inhabitants.
Learn more about the chloride problem, and download your free Low Salt Design Guide on our Low Salt Solutions page!
