Pollution Expert, Public Works Leaders Reflect on Low-Salt Winter
Bleak forecasts lead to relatively clear roads, which is much different from last year’s historic winter. Plymouth Public Works Operations Manager Abbie Browen has now seen both extremes.
“Going from that to this year of not having that– its been very different,” Browen said.
It has made for a unique winter for public works departments, who typically spend much of the winter clearing roadways to keep drivers safe. Thankfully for staff, there’s no shortage of tasks to tackle.
“We are finding other work for them to do,” Browen said. “This year, we [street] swept in January for the first time!”
Browen said Plymouth usually uses 2,000 tons of rock salt a year. So far this winter, they’ve only used 370 tons.
A pile of salt stands tall on Plymouth Public Works’ property.
While this doesn’t affect the already-set budget, it does leave Plymouth with plenty of rock salt for future winters.
“It is so unpredictable on what could happen in any snow season. None of us have that crystal ball to know,” Browen said.
A break from the salt is also a break for the environment. Rock salt contains chloride, which is harmful in waterways.
Salting Smart
Amy Reigel is the city’s senior engineering technician in water resources. She said Plymouth uses a number of methods to keep salt use down in regular years. That includes temperature controls to assess which salt types to use on each truck. It also includes using brining, a technique mixing rock salt with water. It uses less salt than typical salting processes. Plymouth creates brine in-house.
“This is where we actually mix salt with water,” Reigel said, gesturing to a number of tanks on the public works property.
Reigel said every plow driver for the city of Plymouth is trained in smart salting techniques.
That training is offered by the Minnesota Pollution Control Agency. Brooke Asleson is the MPCA’s chloride reduction program coordinator. She explained that the chloride present in rock salt is toxic to fish and insects in wetlands. Once it hits the water, the chemical sticks around.
“We say about one teaspoon of salt in a five-gallon bucket of water is the level at which it starts to cause problems,” Asleson said.
Problems such as water impairments: Brooklyn Center’s Shingle Creek is on the list for chloride impairment. Asleson said it is not the only one.
Shingle Creek is one of a number of waters in the Twin Cities metro impaired by chloride.
“I don’t think Shingle Creek is necessarily that different from other urban streams. We just happen to have that data, that information a little bit sooner,” Asleson said.
This year, Asleson said, MPCA plans to add 13 new waters impaired by chloride to the list.
The warmer weather gives Minnesota roads a break from frequent salting, but researchers are still seeking solutions.
“If it is followed by a winter where we put a fair amount of salt down again, that is not enough time for our water resources to recover,” Asleson said.
In the long term, icy or not, Asleson and the city officials agree: it is important to strike the balance between clear roads and waterways.
If you have roads to clear in the winter, Asleson recommends removing snow and ice physically first. Then, make sure you are using the right products for the conditions; standard rock salt doesn’t work below 15 degrees. She also recommends not over-salting: it takes just a mug’s worth of salt to clear ten sidewalk squares.
Related: Environmental Leaders Launch ‘Low Salt, No Salt’ Campaign
