Low Salt Design
The following article is a peer-reviewed accepted manuscript submitted to the ASCE Journal of Cold Regions Engineering. You can read the final published work on the ASCE Library. Note: you must either be an ASCE subscriber to view the full article, or you can view purchase options for full article access.
Connie I. Fortin1, and Timothy J. Olson, P.E., M.ASCE2
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 Assistant Group Leader, Principal, Bolton & Menk, Inc., 111 Washington Avenue South Suite 650, Minneapolis, MN, 55401-2920; email: [email protected]
INTRODUCTION:
Saltable surfaces, such as roads, bridges, parking lots, sidewalks, steps, and trails, often struggle to regain safe traction after snow or freezing rain events. These surfaces are further compromised by blowing snow and meltwater sprawl, which reenter pedestrian and vehicular travel zones. With minimal or non-existent performance standards for winter design, innovative solutions are essential. Connie Fortin and Tim Olson have introduced new design considerations aimed at enhancing the winter performance of saltable surfaces in cold weather regions have been introduced and practiced. These ideas, presented at the 2024 Cold Regions Engineering Conference, address the chloride crisis, the challenges of winter maintenance, and the potential of Low Salt Design to create a safer and more sustainable future.
Salt is used in cold climates to melt snow and ice or to prevent the bonding of snow and ice to the pavement. Most deicers are chloride-based, with rock salt being the most common. Salt is imported in great quantities to improve pavement friction for the traveling public.
Minnesota imports about 250,000 tons of salt (Clear Roads 2025) each winter for our state highways; significantly more is used on city streets and county roads, and for private use. Many states and countries follow a similar high salt use cycle to manage winter surfaces. While deicers have a short effective lifespan, they leave a long and problematic legacy. Many accept salt as a mainstay in winter travel safety without considering more sustainable alternatives.
MAIN TEXT:
Salt dissolves and moves off-site once it is applied, with the chloride component following the water. Chloride is toxic to aquatic life at low thresholds. The United States Environmental Protection Agency has set a chronic chloride standard at 230 mg/L (Environmental Protection Agency 1988), while the drinking water standard is 250 mg/L (Environmental Protection Agency 2025). A 230 mg/L solution equates to one teaspoon of salt in five gallons of water. Chloride is a conservative pollutant, meaning it does not biodegrade but instead accumulates in the water. Canada has set their standard at 120 mg/L to better protect aquatic life (Canadian Council of Ministers of the Environment 2011).
In addition to harming water, salt damages soil structure and harms plants and wildlife. In response to this threat, Minnesota has created a statewide chloride management plan, asking everyone to reduce their use of salt.
The staggering effect salt has on the stability and longevity of the built environment is recognized. The Minnesota Pollution Control Agency’s Smart Salting for Roads Manual shows that for every ton of salt applied $1,700 to $17,000 of infrastructure damage occurs (Minnesota Pollution Control Agency 2023).
Currently, there is no research quantifying the salt reduction possible with Low Salt Design. However, a shift in strategy is needed, and this shift is most cost-effective through design.
Learning From Winter Maintenance
Winter maintenance operations are now scrutinized for using vast amounts of salt. This has started an industry shift from the traditional ‘more salt is better’ approach to a precision salt use mindset. Fortin has trained over 20,000 winter maintenance professionals on the problems with salt and provided tools for integrating science and technology into winter maintenance. During these difficult conversations on the need for change, maintenance professionals have highlighted that they are not the only sector requiring reform. They have pointed to infrastructure design as a significant factor that complicates their work. Fortin and Olson have taken their knowledge of the problem, combined it with current infrastructure design standards, and created a new cold climate version of infrastructure design: “Low Salt Design.”
Low Salt Design
Low Salt Design strategies aim to improve public safety and significantly reduce reliance on salt. By minimizing the need for salt, Minnesota and other cold climate areas will receive many ecological and infrastructure longevity benefits stemming from this innovative design approach.
Low Salt Design has two basic goals – to speed up pavement recovery and to reduce the impact of the repeat offenders (meltwater sprawl and blowing snow).
Winter performance can be improved by using any combination of these design strategies:
- Using the sun to speed up melting in critical traffic areas (front steps, intersections…).
- Understanding the winter wind direction, intercepting it, and directing snow into dedicated drop zones.
- Controlling the meltwater flow and reducing the footprint of meltwater onto saltable surfaces.
- Designing adequately sized snow storage areas and controlling the resulting meltwater.
- Designing salt storage (both temporary sites such as in shopping malls and permanent sites such municipal salt sheds) to reduce leaching.
- Making surfaces easy to plow by grouping obstacles (signs, benches, lighting fixtures, parking lot islands, etc.) and avoiding acute angles and elevation changes that conflict with the rigid size and shape of a plow blade.
- Considering how vegetation affects shadows and snow storage and its role in managing blowing snow.
- Exploring pavement alternatives that may enhance winter performance, especially in challenging high-traffic areas where simple and cost-effective strategies are insufficient.
CONCLUSIONS:
The integration of Low Salt Design into cold climate infrastructure is not only a necessity but a forward-thinking approach to sustainable winter maintenance. By addressing the environmental and infrastructural impacts of salt, we can significantly reduce its usage while maintaining public safety. Research is essential to quantify the benefits and refine these strategies, ensuring they meet future performance standards.
Designing for meltwater management and understanding the dynamics of snow storage are critical areas that require further exploration. Establishing baseline metrics for current designs will help measure improvements and guide future standards. Additionally, evaluating the cost-effectiveness of snow storage solutions and the impact of thaw/freeze cycles will provide valuable insights for optimizing winter maintenance practices.
As we move towards a more sustainable future, the principles of Low Salt Design should be embraced and continuously improved by civil engineers, architects, planners, and researchers. By doing so, we can protect our environment, extend the lifespan of our infrastructure, and ensure safer travel conditions during winter months.
DATA AVAILABILITY STATEMENT:
No data, models, or code were generated or used during the study (e.g., opinion or dataless paper).
REFERENCES:
Canadian Council of Ministers of the Environment, 2011. “Scientific Criteria Document for the Development of the Canadian Water Quality guidelines for the Protection of Aquatic Life.” 12. https://ccme.ca/en/res/2011-chloride-ceqg-scd-1460-en.pdf
Clear Roads, 2025. “2023-2024 State Winter Maintenance Data and Statistics.” https://www.clearroads.org/winter-maintenance-survey/.
Environmental Protection Agency, 1988. “Ambient Water Quality Criteria for Chloride – 1988.” 8. https://www.epa.gov/sites/default/files/2018-08/documents/chloride-aquatic-life-criteria-1988.pdf
Environmental Protection Agency, 2025. “National Secondary Drinking Water Regulations (NSDWRs).” https://www.epa.gov/sdwa/drinking-water-regulations-and-contaminants
Minnesota Pollution Control Agency, 2023. “Smart Salting for Road Manuals.” 20. https://www.pca.state.mn.us/sites/default/files/p-tr1-13.pdf
Learn more about the chloride problem, and download your free Low Salt Design Guide on our Low Salt Solutions page!
