Ice removal on highways balances cost, other factors
With one of the wettest Decembers in a decade, Hubbard County highway workers kept busy making the roads safe by removing ice. The county's ice removal program strikes a balance between cost, efficiency and environmental impact. "We try to give p...
With one of the wettest Decembers in a decade, Hubbard County highway workers kept busy making the roads safe by removing ice.
The county's ice removal program strikes a balance between cost, efficiency and environmental impact.
"We try to give people the best service we can at the best economy we can," said maintenance supervisor Ed Smith.
Smith said the highway department uses a mixture of sand and salt to combat the ice on county roads.
The ratio varies depending on the temperature and type of precipitation.
"There are 65,000 combinations of storms listed. I think we get every one here," Smith joked.
Generally, the trucks disperse a mixture containing between 11 and 32 percent salt with the sand. The salt aids in de-icing, but is less effective at lower temperatures.
At 30 degrees, one pound of salt can melt more than 45 pounds of ice. At zero degrees, the same salt melts less than one-tenth as much.
Salt loses any efficacy at -6 degrees, explained Smith, so the highway department usually waits after subzero snowstorms until the temperature warms to apply a higher concentration of salt.
"We want to get the best bang for the buck," he said.
Environmental advocates, like the Environmental Literacy Council, say any choice of de-icer carries both advantages and drawbacks.
In large quantities, runoff from salt can seep into nearby soil and the water table, hindering growth of plant life.
High levels of salt also contribute to rust damage on bridges and automobiles.
As an alternative to salt, sand poses less direct environmental harm, but if not properly cleaned up, can clog drainage systems and deposit in wetlands or other waterways.
Environmental Services Office administrator Eric Buitenwerf said the county has not documented any environmental damage from road de-icing, but added some roadside trees may be affected by the salt in more heavily-traveled areas.
Biodegradable de-icers, such as calcium magnesium acetate (CMA) or potassium acetate, break down easier in the ecosphere, but have prohibitive costs preventing widespread application. CMA is also less effective than salt below 23 degrees.
"When it comes down to it, between something that costs $200 a ton and $50 a ton, we will use the $50 chemical," Smith said. "Basically, everyone goes back to sodium chloride."
According to Smith, Hubbard County contracts for street cleaning each spring to sweep the roads and retrieve as much sand as is feasible.
Cleaning crews also scour bridge decks and curb and street drains to prevent clogging and rust damage.
Smith said the highway department uses an average of 250 cubic yards of sand mixture per full road application, typically more than 300 tons, depending on the ratio.
Over an average winter, the highway department will use between 4,000 and 7,000 cubic yards of sand, about 5,600 to 9,000 tons.
Smith added the full complement of 12 trucks can apply mixture to all 522.1 county roads in four to five hours, barring any problems.
The trucks pay special attention to curves, hills and intersections to increase safety, said Smith.
Smith said despite all the precipitation, this winter has generally been less troublesome for road conditions.
So far, the county has used 1,200 of its 3,000 tons of total contracted chemicals, including the salt sold to Park Rapids and some townships, said Smith.
Hubbard County escaped freezing rainstorms earlier this winter. Ice requires more work to keep roads safe, said Smith.
Additionally, Smith said, roads need less maintenance after mid-January, as sunlight and the chemical composition on the road protect driving surfaces more effectively.
Generally, the public understands the road treatment process and takes conditions into account, according to Smith.
"I think the public has been very tolerant," he said. "We try to make the roads as safe as we possibly can."