We are finding salt everywhere. Studies are finding it in our lakes and rivers, in our stormwater ponds, and in groundwater aquifers. Fifty lakes in the Twin Cities Metro Area are already polluted with too much salt, and 30% of shallow groundwater aquifers tested were above recommended levels for salt.
The salt pollution is mainly from winter road and sidewalk de-icing treatments, and the effects are long term. There is no easy or feasible way to remove salt from these waters. The salt is toxic to wildlife. It damages and creates expensive repairs for roads, bridges, and cars. It prevents water in lakes and ponds from mixing because the saltier water is heavier than freshwater. The lack of mixing, in turn, means algae blooms are more likely to occur. Finally, because salt moves, the salt in those shallow groundwater aquifers could seep down into the deeper aquifers where we get our drinking water.
Salt is often over-used based on misinformation. We are accustomed to using salt as a means of melting ice in winter. While we do need some salt to keep roads and pathways clear, we end up with a lot of salt not doing any work, and instead washing off into lakes and rivers.
Since salt cannot be removed from our waters, the best way to protect lakes and rivers and ourselves is to use it more effectively, so we are using less. I hope to clear up some of the myths surrounding salt use, and at the same time keep you from slipping and keep our waters fresh.
Myth: Salt works in all temperatures and conditions.
Rock salt doesn’t work at temperatures below 15°F. Even at 15°F, it takes an hour for salt to melt ice. Rock salt shouldn’t be used when temps are below 15°F because it will get blown or tracked away before it melts anything. Use sand for traction. Don’t use salt for traction.
Myth: If you see rock salt, it’s safe.
Rock salt must be dissolved to work. Many users now get salt wet before spreading to give it a head start. It should take about 20 minutes for salt to melt ice at 20°F. At 30°F, it should only take 5 minutes. So, if you see salt on the sidewalk that doesn’t mean the sidewalk is ice free. It means the salt isn’t melting. Either the temps are too cold or there is no ice to melt (or it was very recently applied).
Myth: No salt means the area hasn’t been treated.
Many road and sidewalk maintenance staff are switching to brines. You can’t always see brines. Brines are a salt-water mix that is poured on the pavement before the storm. Sometimes it looks like stripes, and other times it looks like white pavement. Brines prevent snow and ice from bonding to the pavement. After the storm, the pavement is easier to shovel off, and brines use much less salt than rock salt.
Myth: Sand and salt together get the best of both.
Just pick one. If applied together, sand and salt work against each other. Use sand for traction until temperatures allow for shoveling, or chipping, or for rock salt to work. If you pre-wet the sand, it stays in place better.
Myth: Salt is the best method we have for getting rid of ice.
The best method is not allowing ice to form in the first place. Shovel first before applying anything. Getting the snow off the pavement prevents it from getting compacted or melting and freezing into an icy mess.
Myth: Winter travel can be just like summer travel.
No. Put on your snow boots, stick a shovel and other winter gear in your car, and don’t make unnecessary trips if you don’t have to. If possible, wait on travel till after the winter storm.
Photo credit: Clean Water Minnesota