ROCHESTER, Minn. (KTTC) - Each year, more than 48 billion pounds of salt are poured on roadways nationwide. While all five of the biggest road salt users are in New England, there is still concern here in Minnesota about how sodium chloride on our roads could have negative impacts.
While salt is a necessity for keeping roads safe during hazardous Minnesota winters, an excess amount can degrade roads and bridges, contaminate drinking water and harm the environment.
"It can affect water quality," said Olmsted County Water Resources Coordinator Caitlin Brady. "One of the biggest concerns is at concentrations high enough, it can affect aquatic life."
Road salt can rust water pipes much like it does to cars, leading to worries about possible contamination of drinking water.
"There has been some concern, especially in the Twin Cities metropolitan area, with some surface water that is starting to exceed the threshold they've set for the amount of chloride that is safe in the water," said Brady.
In response, MnDOT has GPS and special software in its plows to reduce the amount of salt being put down.
"We've compiled date on each and every snow event," said MnDOT Rochester subarea supervisor Robert Langanki. "We can actually program our trucks, which have calibrated sanders in them, to be able to put down just enough salt to deal with what's on the road surface itself."
Alternative methods rely on anticipating a snow event before it happens. MnDOT can put down an anti-icing brine solution on the roadways, which uses less salt and sticks better.
MnDOT also designs the storage sheds to prevent any leaking of salt into the water through runoff.
"Every shed is built so that if we have rainfall, everything runs back in the shed so it stays contained in there until we need it," said Langanki.
However, reducing the effect of road salt is not just MnDOT's priority.
"There's a big role that players like the City of Rochester plays in their stormwater design," Brady said. "They've done a really good job with their storm water program."
When temperatures get even colder, MnDOT has to use calcium or magnesium chloride to melt the snow and ice. Therefore, plow drivers receive extensive training before they are tasked with clearing the roadways.