Reduce de-icing and dust suppressant salt use to prevent permanent surfacewater and groundwater pollution.
Best Practice of this action
- Once road and de-icing salts wash into surface and ground water, there is no feasible way to remove the chloride, which means that chloride will continue to accumulate in the environment over time. More than 1 teaspoon of chloride per 5 gallons of water is toxic to fish, aquatic bugs and amphibians. When the road density in a watershed exceeds 18%, water quality problems are likely. In Minnesota there are over 40 surface waters that exceed the water quality standard for chloride and another 40 that are approaching the standard. 75% of Minnesotans rely on groundwater for drinking water. High amounts of salt in groundwater cause drinking water to taste salty, which could restrict its use for drinking, because the cost to remove salt from drinking water using reverse osmosis is expensive. Currently 30% of Twin Cities' drinking water wells have high levels of chloride. Chloride also corrodes road surfaces and bridges and damages reinforcing rods, increasing maintenance and repair costs. Deicing salt accelerates rusting, causing damage to vehicle parts such as brake linings, frames and bumpers.
- See Chloride 101 (MPCA) for a summary of the issue, actions options and staff contacts to help your city take action.
- Pervious concrete use in roadways both reduces stormwater infrastructure and salt use, with Shorewood as a national exemplar.
- See model snow and ice management policies - for city-hired snow and ice management services, that mandate best practices to minimize environmental impacts from sand, chlorides and other chemicals - and for private snow/ice service contractors signing agreements with customers - developed in 2016 by snow and ice management professionals from cities and counties in diverse areas of Minnesota, watershed districts, the Minnesota Pollution Control Agency, the Minnesota Nursery and Landscape Association, and other stakeholders. These policies balance public interests including public safety, equipment and material cost, and environmental impact. See also a shorter model Snowplowing Policy from the League of MN Cities.
- Partnering with others, the MPCA has created and offers a Smart Salting certification program, which has a section on gravel road maintenance and use of dust suppressants, and a web-based winter maintenance assessment tool to help winter maintenance organizations assess operations, identify opportunities to reduce salt use using proven BMPs, and to track progress, which always includes cost savings. The goal is to maintain performance while reducing salt use and saving cities money.
- The biggest salt-reduction action, which is also the most effective way to prevent/melt ice and snow, is to apply liquid pre-wetting and anti-icing solutions to roads. These brines spread more evenly, stay put and begin working immediately because the salt/other components are already in solution. In Minnesota, cities that have switched to tanker trucks have reduced salt use by up to 70% and have paid back their equipment investment in a year or two.