This section of the manual is currently under construction
Low Salt Design is a series of design concepts aimed to create safer winter surfaces by improving pavement recovery and reducing the re-entry of snow and meltwater onto saltable surfaces. Safer surfaces reduce the need for salt. As such, Low Salt Design is a pollution prevention best management practice that can be implemented at the site design phase to minimize chloride pollution exported from developed land areas.
Low Salt Design Goals
The goal of Low Salt Design is to improve winter performance of saltable surfaces for safety and to reduce the need for salt. Low Salt Design takes some pressure off of winter maintenance by reducing demand for deicers.
Potential benefits of implementing Low Salt Design practices include:
- Improved winter safety
- Reduced need for salt/de-icing chemicals
- Preservation and protection of:
- soils and vegetation
- surface and ground water quality
- aquatic habitat
- buildings and other infrastructure that can be damaged by deicing chemicals
- Cost-savings associated with each of the items listed above.
There are two overarching strategies in Low Salt Design.
- Increase the speed of pavement recovery (before the use of chemicals).
- Control the repeat offenders. Repeat offenders are the reentry of blowing snow and meltwater onto saltable surfaces.
Low Salt Design Strategies
Low Salt Design includes ten design principles or strategies that can be incorporated into site designs to create safer winter surfaces and minimize or eliminate the need for salting. There is no inherent hierarchy to this list of strategies. All can be used to improve winter performance; however, the feasibility of incorporating individual strategies will depend on site conditions and context. For description of each Low Salt Design strategy and how to apply them use the links under Low Salt Design strategies and design principles.
Intersection with stormwater permits
Construction Stormwater General Permit
There are no items in permit MNR100001, the Construction Stormwater General Permit, that specifically require the use of Low Salt Design principles or strategies. However, stormwater systems should be designed to address for winter weather considerations. Incorporating Low Salt Design principles and strategies during the design phase of a project may help designer achieve performance objectives associated with winter weather and meltwater management.
MS4 General Permit
There are no items in permit MNR040000, the Small Municipal Separate Storm Sewer Systems (MS4) General Permit, that specifically require the use of Low Salt Design principles or strategies. However, Low Salt Design principles and strategies can be used to achieve compliance with several requirements of the permit listed under MCM 1, MCM 3, and MCM 6.
| Permit item | Summary | Applicability of Low Salt Design |
|---|---|---|
| MCM1: Public Outreach and Education | ||
| 16.5 | Permittees must distribute education materials or provide outreach on the impacts to receiving water, methods for reducing, and proper storage for deicing salt each calendar year. | any/all strategies potentially apply |
| MCM 3: Illicit Discharge Detection & Elimination | ||
| 18.6 | Permittees must have a regulatory mechanism requiring proper storage of salt at commercial, institutional, and non-NPDES permitted industrial facilities. | salt storage strategy |
| MCM 6: Pollution Prevention/Good Housekeeping | ||
| 21.3 | Permittees must maintain an inventory of permittee owned/operated salt storage facilities and must implement BMPs that prevent stored salt from polluting stormwater discharges. | salt storage strategy |
| 21.5 | For permittee owned/operated salt storage areas, permittees must (a) cover or store salt indoors; (b) store salt on an impervious surface; and (c) implement practices to reduce exposure when transferring material from salt storage areas. | salt storage strategy |
| 21.7 | Each calendar year, all individuals that perform winter maintenance activities for the permittee must receive training that includes (a) the importance of protecting water quality and (b) BMPs to minimize the use of deicers. | any/all strategies potentially apply |
| Discharges to Impaired Waters with a USEPA-Approved TMDL that Includes an Applicable WLA | ||
| 22.6 | If the permittee has an applicable wasteload allocation (WLA) for chloride, the permittee must conduct an assessment of the permittee's winter maintenance operations to reduce the amount of deicing salt applied to permittee owned/operated surfaces and determine current and future opportunities to improve BMPs. | any/all strategies potentially apply |
Local Permits
At this time, MPCA has not collected data on local regulations or programs that require components of Low Salt Design in stormwater permitting or development standards. We will update this section if this information becomes available in the future.
When to Use Low Salt Design Strategies
Low Salt Design strategies should be considered in every cold climate design to add winter safety as possible where appropriate.
Some ways to introduce the principles of Low Salt Design in the project design or planning process include the following:
- Incorporate shade analysis into your design process, especially at preliminary stages of design.
- Review winter wind speed and direction for your site to evaluate the potential for blowing and drifting snow in critical areas.
- Bring Low Salt Design principles and strategies into design charrettes to inform discussion of four-season design strategy and potential design conflicts or trade-offs.
- Develop a checklist for developers and designers. Checklists can be very detailed, or very simple, and can emphasize any number of Low Salt Design concepts that are of interest to the organization in charge. See this example from the City of Hopkins, MN.
Additional examples are included in the discussion for each of the 10 Low Salt Design strategies listed above.
Potential conflicts with Low Salt Design
Within Design
Low Salt Design considerations may compete with other design considerations. For example, the desire to have high density of trees on site may be in conflict with the snow storage sizing recommendation of about 20% of the plow shed since snow storage areas should not have trees. The designer will have to consider the pros and cons of both concepts and decide the best overall approach for the site.
With Policy
As Low Salt Design strategies are considered, they may conflict with policy or standards written with other considerations in mind. For example, parking lot islands offer benefits such as traffic calming, beauty, and summer shading. Because of these benefits, islands are sometimes a required element in local design standards for parking lots. However, in winter design they are a plow obstacle and a source of meltwater sprawl, both leading to increased salting and short life expectancy for the vegetation.
Supporting Documents
Download the draft report to MPCA on Low Salt Design guidance:
External Resources
Fortin, Connie. Low Salt Design Guide, A guide to winter infrastructure design. Bolton & Menk, Inc.