Go easy on the salt: Spreading lightly protects water quality
As the Chicago area faces wintry conditions, residents and businesses will look to road salt to provide a stable, safer path along sidewalks, walkways, and streets. The Metropolitan Water Reclamation District of Greater Chicago (MWRD) advocates for a prudent approach to the management of road salt during these challenging weather conditions.
Road salt can provide safety, but it also has unwanted ramifications for the local water environment. Rock salt (sodium chloride) and salt runoff can be harmful to pets, bodies of water and soil along roadways and sidewalks. In addition, excessive road salt can impact vegetation, as well as contaminate groundwater and drinking water.
According to the Salt Smart Collaborative, chloride levels in northeastern Illinois rivers, lakes and wetlands have been on the rise for decades. The challenge with protecting Lake Michigan and the Chicago Area Waterway System (CAWS) is that road salt use increases with urban development, and the more development, the more miles of roads and walkways that need winter deicing. All that salt eventually makes its way to area waterways, and MWRD water reclamation plants cannot always filter it out before releasing it as clean water into the CAWS.
“Road salt can enter sewers or waterways through stormwater runoff and eventually degrade local water quality,” said MWRD President Kari K. Steele. “Once chlorides enter the water, it is difficult to remove them. We urge salt users to use salt in moderation on sidewalks and streets this winter. A 12-ounce cup should be enough for a 20-foot driveway or 10 sidewalk squares. This will help protect our waterways.”
To meet new chloride limits in waterways, the MWRD partners with road salt users on the Chicago Area Waterways Chlorides Workgroup to share knowledge about current practices in winter maintenance. The watershed workgroup also provides deicing workshops to educate winter road maintenance staff, such as laborers, drivers, and hoisters.
The MWRD and partners with the Chicago Area Waterways Chloride Workgroup have developed salt application management strategies, such as calibrating salt spreading equipment, adopting different methods for using salt brines for anti-icing, implementing pre-wetting applications for the rock salt, measuring the temperature of the pavement, upgrading trucks, and tracking pounds of salt used per lane miles. Gradually over time with these new strategies and limits in place, the workgroup anticipates reductions in the chloride loadings to local waterways.
While the MWRD is not a major salt user, its mission to protect the area waterways and environment makes this topic a priority.
“While salt enhances safety and helps us melt ice, we also think it’s important to know that salt use has unwanted consequences for the local water environment,” said Vice President Patricia Theresa Flynn. “This is why we encourage the public to shovel first before using the salt.”
The MWRD has partnered with the Lower Des Plaines Watershed Group to provide the following “Salt Smart/Water Wellness” tips that can help protect the waterways from potential contamination.
1. Shovel first. Salt should only be used after the snow is removed and only in areas needed for safety.
2. Size up. More salt does not mean more melting. A 12-ounce coffee mug of salt should be enough for a 20-foot driveway or 10 sidewalk squares (250 square feet).
3. Spread. Distribute salt evenly, not in clumps. Clumped salt is wasted salt.
4. Sweep. If there is leftover salt on the ground after the ice melts, then too much salt was used. Sweep up leftover salt to keep it out of local rivers and streams.
5. Switch. Untreated salt stops working if the temperature is below 15 degrees. When temperatures drop that low, switch to sand for traction or choose a different deicer formulated for colder temperatures.
