Road salt and sand are a godsend in the middle of a harsh winter, when highway and public works crews drop tons of the stuff, melting snow and providing traction on Maine roads.
By summertime, however, the salt-and-sand mixture doesn’t look so good. Spring rain washes most of it away from the roads and into lakes, rivers, streams and ground wells. Over time, that harms aquatic life and water quality, threatening some of Maine’s greatest natural resources.
That’s why communities need to reconsider how they keep roads clear in the winter. New materials, and new ways for evaluating winter road maintenance, can ensure safety while minimizing the environmental damage caused every winter.
Maine communities, which have been slow to move away from the traditional sand-and-salt application, need to implement these new methods, which have been successful elsewhere at cutting the amount of salt and sand that finds its way into watersheds while lowering costs and keeping roads safe.
First, communities should cut back on the amount of sand used each winter. Drivers like to see the dark brown lines of sand over snow during a storm, but research suggests that after a few vehicles pass over it, sand may be more of an imagined safety blanket than an effective way to provide traction.
In fact, the federal Environmental Protection Agency suggests using sand only for low-speed intersections, hills and curves. In Maine, the Department of Transportation has cut its usage of sand from about 500,000 tons a year in the 1990s to about 60,000 last year, with no impact on safety.
The state was able to make that reduction at least in part because of its increased use of salt brine to coat roads before a storm hits.
Salt brine – road salt and water, sometimes mixed with a nontoxic additive such as Ice B’Gone – lowers the freezing temperature of the snow as the snow falls. This method, along with “pre-wetting,” or applying the brine to rock salt during a storm, keeps more of the chemical on the road, cutting back on wasted material and requiring less salt overall.
WHERE IT WORKS
Some Maine municipalities are doing the same. Pownal has cut in half the amount of salt it uses each storm since switching to a salt solution in 2003.
Lessons also can be learned from other states. In Minnesota, where a study found that around 70 percent of the 350,000 tons of road salt used every year in the Twin Cities area stayed in the local watershed, the state transportation department utilizes a widespread brine program, as well as plow-based technology that gauges road conditions and dispenses the optimum amount of material, cutting back on waste.
By switching to brine, road maintenance efforts in the Burlington, Vt., area went from using more than 16,000 tons of salt and 9,180 cubic yards of sand in 2000-01 to about 11,000 tons of salt and barely any sand during a similar winter 10 years later.
There is some concern that stickier salt brine is more corrosive to vehicles than regular road salt, although the evidence thus far is inconclusive. It seems more likely that the presence of far less salt on roadways will benefit vehicles, and that corrosion can be avoided with a little extra care for the car’s undercarriage.
It is unreasonable to think all Maine municipalities, and the road crews they contract with, can adopt all these new methods in a few years’ time.
But towns and cities that have done the same thing the same way for decades no doubt will find that there are places they can change and cut back, for the benefit of the community’s lakes and streams as well as its coffers.