Winter Stormwater Pollution Prevention Tips
As winter approaches and rain turns to snow, it is still important to consider stormwater pollution. Pollutants
such as soaps, fertilizers, automotive fluids, and pet waste can collect in the snow pack, accumulating until a
thaw suddenly dumps them into the storm water system. Contaminants that end up in the storm drains are
carried off, untreated, to streams and larger bodies of water that are used for drinking, swimming, or fishing.
Here are a few helpful habits to reduce the amount of harmful pollutants entering storm drains this winter
season:
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Winterizing vehicles. Check that your car is not leaking oil or other fluids. It takes only a small amount of
motor oil to pollute thousands of gallons of water. Also, dispose of drained fluids properly. Many service
stations will collect used motor oil and recycle it.
Washing vehicles. On a warm winter day, you may be tempted to break out the hose and bucket to get
some of the road grime off of your car. Take a moment to see where that runoff is going. Does it wash
down the driveway and into the storm drain? If so, all that salt and dirt will enter a stream or pond. Using
a car wash facility may cost a few dollars more, but the water will be treated before being released into
the watershed.
De-icing driveways and sidewalks. While it may be habit to stock up on salt for the winter, many people
would not consider dumping a bucket of salt on their lawn in the summer. But the results are similar. Salt
runs off of your sidewalk and onto the surrounding soil.
It’s not too early to think about environmentally-friendly ways to control ice. Here’s a brief introduction to the
world of ice management:
o Traction Agents – help prevent slipping on ice, but don’t melt it. Sand, kitty litter, and ashes can
hurt vegetation, clog sewers, and degrade aquatic habitats. Cracked corn has been suggested as
an alternative because animals can eat it before it gets washed into the storm sewers in the
spring.
o Deicers – lower the melting point of ice to help remove ice and snow from pavement.
1. Sodium chloride (rock salt) is the most common product because it’s effective & cheap.
On the other hand, it is highly corrosive and ecologically damaging.
2. Calcium chloride is very effective (even at very low temperatures), but more expensive
than rock salt. Because it is so effective, much less chemical can be applied making it
more environmentally friendly than rock salt.
3. Potassium chloride and urea are both fertilizers that can harm vegetation if they are
overused. They are more expensive, but not as corrosive as rock salt.
4. Magnesium chloride is much like calcium chloride, but the application rate has to be
twice as much because it is only 48% active.
5. Calcium magnesium acetate (CMA) is less problematic for soils, vegetation, water
supplies, and concrete. It is non-corrosive, made from corn or petroleum and converts ice
into an oatmeal-like mush. Compared to rock salt it is expensive, but a 50# bag will cost
around $10.
6. Potassium acetate is a reliable choice for smaller areas. It is a biodegradable liquid deicer
with good ice melting capacity.
7. Corn-based liquid concentrates are emerging, primarily for roadway use and are applied
as a spray.
Information courtesy of University of N. Dakota & City of Rochester, MN