State officials say too much salt is being applied to New Hampshire roads this winter, and they worry that warmer, wetter winters could make the problem worse in future.
Nearly 50 water bodies in the state are known to have excess salt levels right now, according to Ted Diers, the watershed bureau administrator for the Department of Environmental Services.
He says too much salt runoff is bad for plants and animals. Wetter, slushier winters – expected to increase in New England with climate change – could make things worse, Diers said, as salt is washed away and reapplied more often than it would be during dry conditions.
"It's kind of counterintuitive that [in] a snowier winter, we may not use as much salt,” he said.
Diers said his counterparts in states like Virginia and Delaware often report using more salt in a given winter than New Hampshire does, due to meltier weather. Scientists expect New England's climate to become more like the Mid-Atlantic's in the coming decades.
DES is training certified salt applicators to limit their salt use based on local conditions, and Diers said residents should be trying to use less, too.
He said it's proven difficult to fight a growing cultural expectation about having plenty of salt on driveways, sidewalks and parking lots, as well as roads.
"It has become sort of normalized that if it doesn't crunch under your feet, you're simply not safe,” he said.
In fact, he said less salt is, most often, just as effective. When the state trains applicators to calibrate their salt use more carefully, he said, it immediately reduces pollution.
