Monday, March 9, 2015

The Impact of Applying Salt on our Streets

Only 4 pounds of salt are needed to treat
1,000 square feet of icy surfaces.
That's only 1/2 cup of salt for one parking space.

By Nicole Soderholm
If you’ve been an avid reader of this blog over the past couple years, you probably recall reading some articles on the dangers of a “high sodium” diet for Minnesota’s water bodies. (See The Slippery Slope of Salt article from January 2014). We’re referring, of course, to using salt for deicing streets and sidewalks. While we haven’t had much snow this winter, it's helpful to reflect on how we treat our streets.

The Bad News: Our Freshwater is Turning Salty

High salt (chloride) concentrations have been increasing in Minnesota’s metro lakes and streams for decades as our population grows and land becomes more developed. Many water bodies have been listed as impaired for chlorides. Chloride impairment means that the lake or stream in question is receiving too much salt to support its intended uses (examples: swimming, fishing, recreation, etc.). 

Salt often finds its way to our water resources from roads and sidewalks via our storm sewer system. You may even notice that roads appear white in the winter, or that salt can do a “number” on your car. According to the Minnesota Pollution Control Agency (MPCA), it only takes 1 teaspoon of road salt to permanently pollute 5 gallons of water.

Image from the video
Improved Winter Maintenance: Choices for Clean Water
Mississippi Management Organization

Permanently, you ask? Remember that salt entirely dissolves in water, so once the salt is in our lakes and streams it becomes impossible to remove without using expensive desalinization systems.

The MPCA has also detected increased salt concentrations in our groundwater, a primary drinking water source for many Minnesotans. In a report released on the condition of Minnesota’s groundwater based on data collected from 2007-2011, the MPCA concluded that 30% of wells in the Twin Cities metro area had chloride concentrations that were too high.

Road salt is impairing streams and lakes in the Metro area,
but it is also impacting our groundwater according to recent studies by the MPCA.
Photo by Chesapeake Stormwater Network.

The Good News: We Can Reverse the Trend!

We’ve all driven in slippery conditions and can probably agree that deicers are necessary for public safety. Water professionals do not generally recommend eliminating this practice altogether, but it has come to light in recent years that there are smarter ways to apply salt that result in more economic and environmental benefits for all.

In fact, many professional road salt applicators are already making great strides in improving the times and rates at which they apply salt. The results? Safer roads, cost savings, and decreased salt runoff to our water resources. To date, over 4,000 individuals from local governments and private companies have attended voluntary grant-sponsored training to become certified in road salt application best practices. Funded by a 319 grant from the EPA through the MPCA, the trainings are taught by Fortin Consulting at various times and locations throughout the state. Visit their website for more information. 

Since many of our readers are not professional salt applicators, let’s review what WE can do as individual homeowners to contribute to the cause.

The next time a snowstorm hits ... later this spring or next winter ... follow these tips.

Shovel Early and Often.

Shoveling is still the most effective and environmentally friendly means of snow removal. When the snow starts to fall, try to shovel early in the storm and throughout its duration to prevent ice formation.

Cartoon by Randy Bish

Less is More.

When it comes to salt, you need less than 4 pounds of salt per 1,000 square feet to do the job. A good way to remember this formula: This is about equal to half of a large coffee mug of salt for an average-sized parking space. Test it out on your driveway sometime so that you can remember what the application looks like. Adding more salt does not increase the speed of melting, but it will increase the amount of salt that winds up in our nearby water bodies.

Image from the video
Improved Winter Maintenance: Choices for Clean Water
Mississippi Management Organization

Know Salt's Limits.

Sometimes in Minnesota it’s simply too cold for salt to be effective at melting ice. Regular ol’ salt does not work below 15 degrees F. Adding more and more salt when really cold temperatures hit just doesn’t work. Instead, use sand for slippery areas or a different deicing product designed for lower temps.

Sweep Up, Clean Up.

When salt has done its job and you’re left looking at salt particles on dry pavement, sweep up the remaining product so that it doesn’t get washed away during the next snowmelt or rainstorm. The best part is you can reuse this leftover salt for the next storm.

Identify Ice-Prone Areas.

We’re all familiar with that one dip in the pavement or section of the driveway that collects water. These are the biggest problem areas when it comes to ice. Try to identify these areas and fix them during the summer. Not only will your property be safer in icy conditions, but there will be fewer areas that require salt.

Hire a Professional.

If you choose to hire someone to remove snow for you, look for a contractor that has earned a salt applicator certification. A list of contractors, as well as other information on road salt, can be found on the MPCA’S Road Salt and Water Quality webpage.

Watch this Video.

Improved Winter Maintenance: Choices for Clean Water is a video filmed by Senator Foung Hawj that answers these questions:
  • What are the best tools homeowners can use to keep driveways and sidewalks safe?
  • What deicers work under icy conditions and should we be using them?
  • What do deicers and sand do to our lakes, streams and groundwater?
If you care about the health of our waters, watch this video to find out what you can do to minimize your impact on the environment as you manage snow and ice on your property.

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