The below submission is from Kevin Strauss, of the Cannon River Watershed Partnership (CRWP)
When cold weather hits, some people try to stay inside as much as possible. We try to limit outdoor activity to short forays, to shovel snow or get the mail.
So, it’s not surprising that in this season of cold, some people forget that what they do on their property, even in the middle of our near-arctic winters, can add pollution to the Cannon and Straight rivers.
As you might have guessed, I’m talking about excessive sidewalk salt.
We have used salt for decades to keep sidewalks and streets safe and clear of ice. Salt, or sodium chloride (NaCl), lowers the freezing point of ice, effectively “melting” it on pavement. Unfortunately our use of salt is also adding salt to our rivers, lakes, and in some cases, even our drinking water. Salt is one of two river pollutants (the other being nitrogen fertilizers) that are actually increasing in the Straight and Cannon rivers. So, it’s a problem we need to deal with.
In addition to polluting our rivers and lakes, excess salt can corrode sidewalks, roads and bridges, costing taxpayer money when cities need to fix those surfaces. That’s why many cities and businesses in Minnesota have been retraining crews to keep streets clear, while at the same time, using the bare minimum of salt or brine in the process.
While it’s great to see cities and businesses reducing their salt use, we use salt on our property as well. So as winter comes to our region, the Minnesota Pollution Control Agency (MPCA) has these tips for winter salt application:
• Shovel First, Second, and Third. The more snow and ice you remove manually, the less salt you will have to use and the more effective that salt can be. Whether you use a shovel, snow blower, snow plow or ice scraper, get out there as early as you can and keep up with the storm. Once you’re done, you may even decide that you don’t need to apply any salt to keep your sidewalk or driveway clear of ice. Keep in mind that if you let snow sit, and get trampled by pedestrians, it will turn into packed snow and eventually ice.
• 15°F is too cold for salt. Most salt stops working at this temperature. Use sand instead for traction, but remember that sand does not melt ice, it just helps people and car tires to get a grip on that ice.
• Slow down. Winter is a time for slippery roads, no matter how much salt road workers are applying. Drive for the conditions and make sure to give plow drivers plenty of space to do their work.
• Be patient. Just because you don't see salt on the road doesn't mean it hasn't been applied. These products take time to work.
• More salt does not mean more melting. This is one case where “too much of a good thing is not a good thing.” Use fewer than 4 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. Consider purchasing a hand-held fertilizer spreader to help you apply a consistent amount of salt.
• Sweep up the extra salt and sand. If salt or sand is visible on dry pavement, it is no longer doing any work. And when the snow and ice melt in the spring, that water will wash these potential water pollutants into nearby rivers and lakes. You can use this salt or sand somewhere else or throw it away. Excess salt can also damage pavement over time. So, there are several reasons to clean up excess salt.
If we all do our part, we can help keep the Cannon and Straight rivers clean and healthy while at the same time also keeping our sidewalks, driveways and roads clear of ice this winter.