Sunday, April 5, 2015

Road Salt Use Wasteful, Damaging

TOS_SALT_BRINEAll of a sudden, sap season is here and winter’s on its way out. Chances are though, a few more snow or ice squalls are still to come. The next time you find yourself driving behind a big plow truck, take a look at what’s coming out of the spreader. What is used makes a difference for wildlife, especially as the snow melts.

Since the 1940s, rock salt, and lots of it, has been a boon to Northeast drivers. As a tool, it is simple and effective. The crystals are dropped evenly along the road, mixing into the slush over time by the weight of passing vehicles. The slush melts away because the combination of salt and water freezes at a lower temperature than water does alone.

However, the traditional approach of spreading dry rock salt is remarkably wasteful. Studies show that 30 to 40 percent of dry rock salt spread bounces and scatters off the road into the grass or nearby woods. This is bad for transportation budgets, and it’s also harmful to the environment. Most immediately, it’s a hazard for birds, that will die if they ingest too much of it, and to other wildlife which it attracts to busy roads.

As the salt dissolves into meltwater, and breaks down into sodium and chloride ions, it causes other problems. In high concentrations, the chloride can brown leaves and needles, sometimes killing trees and shrubs near the roadways. It can also end up deep in the ground, sometimes ruining the taste of well water. But its largest effects are not ones you can immediately see or taste. When the salt reaches our lakes and rivers, it changes the water chemistry.

The concentration of chloride ions in waterways has gone up steadily over the past seven decades in northern states where rock salt is used. Scientists now regularly find readings between three and ten times what they were in the early twentieth century. Amounts much higher than that, by a factor of 100 or 1,000, have been found in small ponds and streams downstream from large highways and parking lots. At these higher levels, chloride can kill aquatic insects and even fish.

In response to these concerns, as well as the rising cost of rock salt (around $60 a ton to around $80 over just the past two years), state transportation agencies in the Northeast have been increasingly using a salt brine slurry. Wetting the rock salt with brine eliminates salt clumps and makes the salt stick immediately to the road. That increases melting efficiency and reduces the amount of salt needed to clear our roads.

To read more about salt use on Adirondack roads and its environmental impacts, click here.

Kristen Fountain is a freelance writer living in Vermont’s Northeast Kingdom. The illustration for this column was drawn by Adelaide Tyrol. The Outside Story is assigned and edited by Northern Woodlands magazine and sponsored by the Wellborn Ecology Fund of New Hampshire Charitable Foundation: wellborn@nhcf.org

 

 


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4 Responses

  1. Bruce says:

    The slurry is being used as far south as North Carolina and beyond, too. Until we find a better system, we’re stuck with salt in all of its forms. Whatever goes on the roads, will eventually find its way into the waterways and the ground. Studded tires, and even chains are a viable alternative to the constant use of salt. Learning how to drive on snow and ice are good, too. Every winter I see 4WD and AWD vehicles in ditches, some upside down. This is not caused by the conditions as much as the drivers believe those features make them invincible.

    One of the first winters I lived in North Carolina (from Oswego Co. NY) I had a very rough time getting home from work one night (30 min became 5 hours) because the roads had a thin skim of fresh snow, and I had so-called “All Weather” tires. The traffic was backed up for nearly 15 miles because of a wreck on a bridge. I eventually pulled my Volvo off the road and let a neighbor bring me the last few miles with his 4WD truck. Like the Adirondacks, western NC is mountainous, having few alternatives to the main arteries. The next day, it was as if nothing ever happened. I went back to get my car about lunch time. Right after that, I went to a tire dealer to get a set of studded tires installed. I was able to go again, no matter what came down from the sky the rest of that, and subsequent winters until I bought my first AWD vehicle (a Subaru).

    My point is this: there are alternatives to the constant salting, but people like to feel state and county DOT’s; will make it possible for them to get back and forth as if snow and ice were not real issues. Whatever happened to getting up early and allowing an extra 30 minutes for iffy conditions? Have we become too convenience oriented?

    • Big Burly says:

      What may become a powerful inducement to reducing salt use will be cost. The highway / DOT budget in local towns is typically the largest component of the property tax levy, after school taxes. Convenience or not, until the economy begins to expand again, there are a lot of property taxpayers asking why not find a better, less destructive and less expensive way of keeping roads passable. Common sense, practiced when I was growing up, dictated that leaving earlier to allow for “iffy” conditions was the smart and safe option. Car bodies didn’t rust out so soon either.

  2. M.P. Heller says:

    Bruce makes excellent points about all season tires and the false security of AWD or 4WD. There is simply no such thing as an all season tire in this part of the world. Thinking otherwise is simply the act of falling into a clever marketing trap. With many out of area readers on this website, it’s an important message for readers who hail from distant locations to understand. Simply put, the rubber compound used in all season tires starts to severely lose its ability to grip road surfaces at temperatures below 45°F as compared to a winter rated tire which uses a compound that remains more supple at temps below 45 and therefore has a much greater degree of traction in these conditions. Tread design differences also play a factor between these two varieties of tires as well, but the single biggest difference maker is the material used to produce them. Oftentimes a worn winter tire will provide better traction in cold and snowy conditions than a brand new all season one will. This is because of the material difference and has much less to do with the tread type or condition.

  3. Charlie S says:

    “Have we become too convenience oriented?”

    I think you know the answer Bruce.