Deicing salt is essential for winter road safety and mobility. Although The Center for Watershed Protection indicates that Sodium Chloride has little effect on Aquatic Biota in large or flowing bodies at current road salting amounts, the City of River Falls uses a number of different strategies to minimize any possible impacts to the environment from traditional deicing techniques. These include: applying less salt, applying alternate deicers, changing the timing of application, modifying spreaders and implementing salt storage regulations.

• Application Rate

  Decreasing the application rate can significantly decrease environmental impacts. The City of River Falls typically applies salt only at intersections and to a select few higher volume roadways within the City.

• Alternative Deicers

  The City is staying up to date on alternative deicers. Unfortunately, most deicers have some negative environmental impacts. The City currently utilizes some magnesium chloride in addition to the typical sodium chloride.

• Timing of Application

  By applying deicers at the appropriate time, the amount of deicing material needed can be decreased. The City of River Falls attempts to apply deicers before snow falls, based on forecasts. If the forecasted storm does occur, it will take less deicing material to melt snow in this condition. The drawback to this method is that, if forecasting is inaccurate, deicers are applied unnecessarily.

• Modified Spreaders

  Deicers are often over-applied because much of the material bounces off the road surface. The City has modified its' equipment to pre-wet salt during application. Pre-wetting provides moisture to make brine resulting in faster melting action that reduces overall application rates. In addition, the wet salt has less tendency to bounce or be blown off the road by traffic reducing application rates by an estimated 20% to 30%.

• Salt or Deicer Storage

  The City of River Falls stores Salt on an impervious surface to prohibit groundwater contamination. Furthermore, salt piles are placed in a structure protected from rainfall, eliminating contamination of runoff by exposed salt. This Salt storage facility is licensed annually by the state of Wisconsin.

Related Links

Center for Watershed Protection

Rating Deicing Agents- Road Salt Stands Firm (Article 139 from "The Practice of Watershed Protection")

The Stormwater Managers Resource Center

The Stormwater Center has created a manual for storm water practices in cold climates.  Chapter 8 is Pollution Prevention and discusses road salting and deicers.