Snow and Salt

Here’s what the Minnesota Pollution Control Agency has to say about the salt we use when it snows.

For the sake of our lakes, keep your pavement on a low-salt dietSt. Paul, Minn. – As Minnesota begins to deal with heavy snowfall and cold temperatures, most of us will rely on a crucial tool to clear the roads and sidewalks: salt. It is estimated that we use more than 350,000 tons of salt on the metro area roads, parking lots and sidewalks annually.  According to the Minnesota Pollution Control Agency (MPCA), our waters should follow the advice our doctors have been giving for years: stick to a low-salt diet. Rock salt, which contains chloride, is the most commonly used de-icer. But, much like table salt, rock salt’s benefits are peppered with danger. Salt saves icy roads but can have the opposite effect on the nearby environment. Its public safety benefits come with environmental drawbacks like polluted waters and poisoned aquatic wildlife.

In the Twin Cities metro area, 78 percent of the salt applied to roads stays within the region’s watershed. Chloride from salt eventually finds its way into the groundwater. Once in the water, it becomes a permanent pollutant and continues to accumulate in the environment over time. In other words it doesn’t melt or go away.

High levels of salt can be harmful to fish and other freshwater life and can affect groundwater and drinking water supplies, infrastructure, vehicles, plants, soil, pets, and wildlife.

“Too much chloride has serious water quality consequences.” said Brooke Asleson, chloride project manager at the MPCA. “Less is more when it comes to applying deicing salt. It only takes one teaspoon of road salt to pollute five gallons of water.”

To address these issues the MPCA partnered with local and state experts in the 7-County Twin Cities Metropolitan Area (TCMA) to create a plan for effectively managing salt use to protect our water resources in a responsible and strategic approach. The goal of this plan is to provide strategies to help local partners reduce salt use while providing safe conditions for the public.

Improving practices for de-icing roads, parking lots and sidewalks will not only benefit water quality, but also lead to long-term cost-savings as a result of purchasing less salt and reduced impacts on vegetation and corrosion of infrastructure and vehicles.

A key challenge in reducing salt usage is balancing the need for public safety with the growing expectation for clear, dry roads, parking lots, and sidewalks throughout the winter. Notable efforts to improve winter maintenance and reducing salt usage while maintaining public safety have already been made by a number of winter maintenance organizations. The intent of the plan is to build on those efforts and to assist agencies, local governments and other stakeholders to determine salt reduction strategies to restore and protect Minnesota’s water resources.

How can you make a difference?

Currently, there are no satisfactory alternatives to salt that are environmentally safe, effective and inexpensive. However, we can reduce salt at the source through application strategies.

Each person contributes to the attitudes and practices that have created a high and steadily growing volume of salt that is used each year. Citizens set the expectation that winter maintenance crews must meet, and they use salt on personal property such as sidewalks and driveways in the winter. Below are a few simple steps the public can take to protect water resources.

Support smart salting. Support local and state winter maintenance crews in their efforts to reduce salt use.

Shovel first.  The more snow and ice you remove, the less salt you will have to use and the more effective it can be. After the ice has been broken up, you can decide whether deicer is even necessary to maintain traction.

Apply salt before the storm. Salting before can prevent snow and ice from building up on roads, therefore reducing overall salt use.

Slow down.  Drive for winter conditions, and be courteous to slow-moving plows. The slower they drive, the more salt will stay on the road where it’s needed.

More salt does not mean more melting. Use less than four pounds of salt per 1,000 square feet (an average parking space is about 150 square feet). One pound of salt is approximately a heaping 12-ounce coffee mug. And be patient: salt takes time to work. Applying more will lead to unnecessary contamination.

15 degrees is too cold for most salt to work. Most salts stop working at this temperature. In frigid conditions, use sand for traction.

Sweep up extra salt. If salt or sand is visible on dry pavement, it is no longer doing any work and will be washed away.  The excess can be swept up and reused for the next snow or disposed of in the trash.

Your actions matter. Get involved. The public has a critical role in helping solve this challenge of providing safe winter travel conditions and protecting our valuable water resources.

For more on what you can do to reduce chloride in our waters, or to read more about MPCA’s role on this issue, visit the agency’s Twin Cities Metro Area Chloride Project webpage.

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