One might think thawing signals a winter storm’s end, but a whole host of issues just begins when the ice finally melts.
Thawing ice presents similar problems to any water runoff. According to Lebanon Stormwater Coordinator Brian Chomicki, two major contamination sources after a snowmelt event come from “brines used to keep the road de-iced and the runoff from thawing agricultural livestock wastes and pet wastes.”
“As the snow and ice melt, everything it has come in contact with potentially discharges to our surface waters. This discharge carries with it a variety of substances that affect water quality,” Chomicki said. “Successful efforts have been made in recent years to reduce the toxicity and improve the effectiveness of these road brines used by state and local governments.”
The three main types of road salt are halite, potassium chloride and calcium magnesium acetate. Halite isn’t good for roadside vegetation. Potassium chloride, a.k.a potash, is a powerful fertilizer that causes uncontrolled vegetation growth. Calcium magnesium acetate is the safest for the environment but is so expensive it’s cost prohibitive.
According to its website, the Tennessee Department of Transportation uses salt brine to help prevent snow and ice from accumulating on highways. The brine is, “a combination of water, salt and other additives that helps to prevent freezing from occurring.
Morton Salt, a nationwide contractor for many states’ departments of transportation, explains brining like this. “First, salt is spread on the snow or ice-covered road. As the salt particles come into contact with the snow or ice, melting beings and water is produced. This water containing dissolved salt is called brine. Brine freezes at lower temperatures than regular water so it remains a liquid in sub-zero degrees.”
Whether the roads get brine in advance or in response to a winter storm event, the presence of salt remains. The West Michigan Environmental Action Council addresses this issue in their state every year. According to WMEAC’s water programs manager, Kristi Klomp, “snowmelt runoff containing road salt squelches roadside vegetation and can produce high sodium and chloride concentrations in ponds, lakes and rivers, creating toxic conditions that threaten aquatic life.”
Aside from aquatic life, this runoff can impact pets. Chomicki said the compounds from salted surfaces and melted runoff can get between your pets paws and irritate them. He recommends “avoiding untreated surface waters that may be coming from urban areas due to salts and animal waste concerns until well after a melt event.”
According to the Environmental Protection Agency, a single cubic foot of compacted snow and ice can contain up to three gallons of water. So even if Wilson County only gets a few inches of snow, all that water adds up quickly. After the thaw begins, previously frozen water now has to find somewhere to go. This is how dust, debris and waste make their way to water sources. Water runoff from snowmelt can contaminate private wells by washing microorganisms into the well system.
Other contaminants like nitrates from human and pet waste reach water sources through surface water movement. Earlier this year, a Sioux Falls meteorologist went viral with a PSA about how birds’ fecal matter accumulates on rooftops during snow events. Eventually, she said, these compounds will track to a water supply, so “don’t eat the icicles.”