Melting Snow, It’s Stormwater Too!

Stormwater runoff can come in many forms, including melting snow. Winter snow often brings a unique feel to North Carolina as it doesn’t happen often: making for beautiful photos and lots of family fun. However, it’s not long before the sun comes out to expose a host of issues created by the melting snow.

Heavy rains sweeping across your yard and driveway carry pollution and high volumes of water into our nearby streams, lakes, and other waterways. Melting snow does the same things. Both rain and snow melt can seriously impair North Carolina waters when they travel over the land in our developed communities.

In winter, melting snow actually causes a few unique stormwater problems. Because the ground is often frozen at the surface, melting snow can’t infiltrate into the soil the way a light or moderate rain would be able to. So even a small amount of snow can cause localized flooding on your property. When snow builds up over several small storm events without melting in between, it can turn into large winter storm impacts when it finally does melt – leading to potential community wide flooding events. In both cases, that standing and flowing water on the ground is picking up all kinds of debris, pollutants (especially deicing salts and chemicals), and litter that will find their way into nearby streams.

When shoveling/plowing snow this season, pay attention to where you place it. Try to pile snow in areas where it will have a chance to infiltrate, not runoff!

Winter Stormwater Pollution Prevention Tips

Start shoveling early! The more snow you remove, the less salt and sand you’ll need. Below are some do’s and don’ts when shoveling or plowing snow

snowmelt

Snow and Your Rain Garden

Normal snow accumulation does not pose a threat to rain gardens, so there is no need to shovel a rain garden. However, heavy snow loads can weigh down and saturate your garden and hurt plants. Pile snow uphill from the rain garden so when the snow melts the rain garden can do what it is designed to do.

Do:

  • Pile snow in locations with the most opportunity to infiltrate into the ground.
  • Pile snow in areas where water does not pond.
  • Clear away any snow that may have been thrown onto the storm drains
  • Clear your downspouts to allow melting roof snow to flow and not collect at your foundation.
  • Pay special attention to places that are eroding during snow melt, and make a plan to improve these areas in spring using plants that can slow and stop erosion, like native grasses and meadow plants or native trees and shrubs.

Don’t:

  • Do not pile snow on top of storm drains or near water bodies and wetlands.
  • Do not pile snow onto rain gardens or bio retention areas.
  • Do not over use de-icing chemicals and salts, and avoid spreading around sensitive areas like waterways and your private well.

Tips to Avoid Using Salt as a De-icer

More salt does not equal more melting snow. Follow product instructions when spreading deicing material and give it time to work. Sweep up any material remaining after the snow/ice melts.

When temperatures hit 15° F or below, salt is not effective. Consider using traction materials that contain an acetate, potassium chloride, magnesium chloride, or cracked cornmeal instead of sand or kitty litter.

Stay safe and warm this holiday season!

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