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Thread: Regional differences in snow removal and their environmental effects

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    Cyburbian dobopoq's avatar
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    Regional differences in snow removal and their environmental effects

    I know that in the D.C./Baltimore area, salt is commonly applied both before and during snowstorms. When it snows, an armada of plows always seem to have the roads clear in less than 24 hours, and rarely allow so much as four inches to accumulate unplowed on significant arteries. But I have noticed in just the last 1-2 decades I have been conscious of it, that the quantity of salt used each winter seems to have increased a great deal (despite normal snowfall totals). It's no mystery that during said time period, average commute times have been increasing as people have chosen to live in evermore far-flung exurban developments. Concommitantly, the number of cars and miles of roads in service have also increased.

    More recently, I noticed that in the Portland, OR area, a mixture of gravel and sand was more popular. And many drivers apply chains to their wheels despite the extra wear and tear this puts on roads. Knowing that high salinity is potentially problematic to the water table and local agriculture, I suspect this is part of the reason why Portland chooses to rely on a more traction based method as opposed to a chemical melt method. Salt also tends to rust-out cars, but as fiberglass bodies have become more common in recent decades, this probably isn't as big a problem as it used to be. It may even be a cause for the increased salt use I perceive.

    So I wonder, what do people know about the trends for salt use in snow removal in the U.S., Canada and other snowy parts of the planet? Does it seem like it's been increasing over the past few decades? What is known about the consequences of salt use? What is known about the consequences of gravel and sand use? Or how about the damage done to roads by chains on tires? Are different methods more popular in part based on whether temperatures are very extreme, and or if snow totals are very heavy? Obviously, salt alone won't take care of 3 feet/1 meter of snow.

    I'm curious as to how the answers to these questions differ regionally, as well as the answers themselves. So please include locational info for the areas for which you describe snow removal methods, trends and their effects. Also, how do you explain any trends that you see are occuring? Thanks.
    Last edited by dobopoq; 26 Feb 2006 at 4:49 AM.
    "The current American way of life is founded not just on motor transportation but on the religion of the motorcar, and the sacrifices that people are prepared to make for this religion stand outside the realm of rational criticism." -Lewis Mumford

  2. #2
    Cyburbian Emeritus Bear Up North's avatar
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    Your questions led me on a Google. I looked at web sites of some of the Great Lakes' area departmetns of transportation. Some sites had "Frequently Asked Questions" that included inquiries on tons of salt and/or sand, other chemicals used, physical sie of salt and/or sand, effects of same at different temperatures and on different types of roads, etc.

    An amateur like me confused easily.....so many things to consider.

    Concerning the environmental impact, the reading I did indicates that most testing shows no real problem with these substances, if done as per the requirements for the area they are in. Here in Ohio it is rock salt, of a specific size, to the tune in an average year of 500,000 tons statewide. In Michigan, it si about 750,000 tons of rock salt and about 250,000 tons of sand.

    I know from my winter trips up north that sand and salt are sometimes mixed and some of the litte-traveled roads int he far north just get plowed, with no salt or sand. These roads get a snow base and stay that way all year long.

    Good questions. I will follow-up with a friend who works for the Ohio DOT, Lucas County office.

    BTW.....Toledo has only had about 5 inches of snow during all of January and February. That is an incredibly LOW amount. (We are expecting a whopper on Monday.....one inch!).

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    Cyburbian safege's avatar
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    Operation pre-wet

    3.** Pre-wetting and Direct Liquid Application, Monitoring of Pilot Implementations

    Pre-wetting and Direct Liquid Application (DLA) are alternative methods of applying salt to enhance plowing and remove snow in winter. Pre-wetting involves the application of a small quantity of liquid to salt granules as they are spread on the pavement. Pre-wetting improves the performance of salt by reducing bounce and scatter loss from the pavement, and by increasing the melting rate at which the salt dissolves into brine, enhancing its ability to melt snow and ice. Implementation of pre-wetting across the province began in 2000 and has now reached 59% of the spreader fleet used on provincial highways. All of MTO’s new spreading contracts require that spreaders be equipped with pre-wetting capabilities.

    Two-lane Direct Liquid Application by tanker truck

    A variable application rate system for pre-wet salt was developed from earlier years’ test data, resulting in reductions in salt application exceeding 20% under certain conditions with improvement or no change in service levels. Salt reductions associated with the switch from dry to pre-wet salt across the province are being tabulated from maintenance records for the 2002/03 season, and the 2001/02/03 test data from Elsinore will be analyzed to determine whether additional reductions are warranted.

    Pre-wetting is also being used to assist sand in adhering to ice and snow pack when the temperatures are too low for salt to be effective, reducing the number of applications of sand required to maintain traction on the road surface.
    DLA is the application of liquid chemical sprayed directly onto the road surface. The chemical prevents the formation of frost and black ice and prevents snow and ice from bonding with the road surface. Pilot implementation of DLA began in Eastern Region in 2000, and has now expanded to 9 patrol areas across the province. It has generated a positive response from MTO staff and contractors, improving service levels and reducing the number of full salting and sanding trips where it is used by as much as 30%. Experience gained during the pilot implementations suggest that application rates can be reduced and that effectiveness can be enhanced in some conditions using lower rates. These rates are being tested at Elsinore and elsewhere under closely monitored conditions. Lower rates may also decrease costs by reducing the number of spreaders needed to cover a route.

    http://www.mto.gov.on.ca/english/tra...04/03-04fs.htm

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  4. #4
    Cyburbian dobopoq's avatar
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    Wow, thanks for the info. I not sure I want to get that technical about it. I was just kind of wondering - on just a gut level, whether anyone else has perceived a trend toward using more salt over the last few decaades.

    Or for those of you who are over 40, did it seem like they used as much salt on the roads in the 60's and 70's as they do today? I'm talking in relative terms. Of course there are more people today, and more cars and roads to run them on, so you can't judge trends based just on the quantity (in tons) of salt used over the years. Maybe what I'm noticing is just peculiar to Baltimore, cause it sure seams like they've layed down a crap load of salt everywhere.
    "The current American way of life is founded not just on motor transportation but on the religion of the motorcar, and the sacrifices that people are prepared to make for this religion stand outside the realm of rational criticism." -Lewis Mumford

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    Cyburbian jmello's avatar
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    I know that in MA and RI a mixture of sand and salt is used rather heavily. Certain stretches of roadways bordering important watershed areas are labeled "No Salt Zones." Both states have an armada of state and localy owned plows and also contract out much of the work during large storms. MassHighway just forced all of its private plow operators to carry GPS tracking devices on their routes to ensure contract compliance.

    Boston is usually covered with sand by April, when the street sweepers come out.

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    Cyburbian Cardinal's avatar
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    In Wisconsin and Illinois I know that there are other chemicals mixed in with salt, which help improve the melting process. I remember the DPW director saying these chemicals were not as damaging as salt, and the amount being applied was less than it had historically been. In addition, there was a concern about snow storage. At one time they had been piling it on the lake. This evolved into loading it onto a truck and hauling it to the city garage, but even there, when it melted it would drain into the river. The city was keeping an eye out for a location where they could construct a snow storage basin which would prevent the meltwater from draining off.

    In Colorado it is mixed. The town where I lived did not plow or salt. There was no budget and no equipment. This is what happens when the population goes from 500 to 15,000 in a decade. The town's leadership never stopped to consider that the new people moving in would want services the town had never provided. On the other hand, the state has their plows and salt/gravel trucks sitting alongside the highway when there is a prediction of snow. It is a real challenge keeping I-70 open through the mountains.

    As for snow chains or studs, most midwest or Great Lakes states have banned them, as they do an incredible amount of damage to the roads. In reality, you do not need them with new tire designs, unless you have a need to negotiate steep hills. This is the reason they are required, at times, heading up some of the mountain passes.
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    Member CosmicMojo's avatar
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    I *think* in Richmond, VA they use chemicals rather than salt.
    Our problem is not so much snow, but thin dangerous layers of black ice which is hard to see on the road. That's why we need chemicals to melt it.
    Further north, they get more snow because all the air layers are colder than down here. Here, the snow falls through a warmer air layer, melting before it falls on the ground. It then freezes into ice which is much more dangerous to drive on.

  8. #8
    Cyburbian
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    It differs in UT depending on the agency. UDOT has started to use a brine solution that supposedly increases the ability of the salt to melt the snow and also keeps it from refreezing. The smaller city and county crews use mostly salt. Salt is in abundance in this area, so my guess is that it is cheaper to use. Our parking lot was white from salt after the frist snow storm this year. It took three or four rain storms to clean it up. That can't be good for the surrounding vegetation.

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    Cyburbian michaelskis's avatar
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    Michigan’s Upper Peninsula uses a combination of a de-icing chemical and contractor’s sand because it is usually too cold for salt to work. There are also many areas that will use a fine gravel about the consistency of kitty litter that is mostly a sand/clay mixture.
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    Cyburbian dobopoq's avatar
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    Quote Originally posted by jmello
    I know that in MA and RI a mixture of sand and salt is used rather heavily. Certain stretches of roadways bordering important watershed areas are labeled "No Salt Zones.".... .......Boston is usually covered with sand by April, when the street sweepers come out.
    Interesting - Talk about seasonal work.
    Quote Originally posted by Cardinal
    As for snow chains or studs, most midwest or Great Lakes states have banned them, as they do an incredible amount of damage to the roads. In reality, you do not need them with new tire designs, unless you have a need to negotiate steep hills. This is the reason they are required, at times, heading up some of the mountain passes.
    This explains why I've seen chains/studs in Portland, but not in D.C./Baltimore. Portland - the west side especially, has some very steep hills. The mid-Atlantic has some hills but they're much more rolling and gradual. Ironically, Portland roads are quite good compared to Baltimore. But Baltimore is much older and has been losing tax base for half a century. As for Portland's preference for sand/gravel as opposed to salt, it couldn't be because it too's cold for salt - The climate is milder than the east coast. I don't know about the cost, but I'm guessing salt is less popular out of some perception that salt is less damaging to the ecosystem.
    "The current American way of life is founded not just on motor transportation but on the religion of the motorcar, and the sacrifices that people are prepared to make for this religion stand outside the realm of rational criticism." -Lewis Mumford

  11. #11

    Chemicals

    Here in Sandusky, we use primarily rock salt (pure NaCl), however this year we coated some of our salt with Mg, which is supposed to reduce the corrosive effects and neutralizes rock salt to minimally effect the water table/wastewater.
    Ice forms at 32 degrees, and Rock salt is good down to 15 degrees, wheras the treated salt is good down to -35. The chemicals Mg or Ca alone are good down to -60 range. Depending on your climate/region I would vary the salt treatment. Sand usage in rural areas would eventually build up in sewer systems and does not coagulate well at the sewer plant, not to mention be a street sweeping headache. Rural areas may be fine for that use. That being said, sand alone doesn't melt snow or ice, but rather provides traction, which would be valuable near rural intersections. The excess sand would end up in the shoulder/berm areas, similar to undissolved salt.
    ODOT uses pure liquid chemicals, either Calcium Chloride or Magnesium Chloride.
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  12. #12
    Cyburbian abrowne's avatar
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    Waterloo, Ontario uses so much salt that its roads are stained white almost all winter. Deplorable.

  13. #13

    Too much salt

    Using too much salt can have negative impacts on a roadway. Most importantly, it dries out the asphalt surface, which turns it to grey rather than black. Drying out the pavement too much takes away asphalt's ability to be flexible, causing increased expenditures in seal coating and crack sealing and speeds up the deterioration process of asphalt. This greying of the pavement also reduces its ability to absorb heat from the sun like black asphalt, so it will not heat up as easily on sunny days. There is alot to be said for applying the approprtiate amount of salt according to the thickness of snow and ice. We typically apply 200-300 lbs per lane mile, which is for a standard snowfall. We use less on ice. Treated salt uses about 1/3 less (166-200 lbs/lane mile). Our policy is to salt main roads and side street intersections. We only plow side streets unless they are really icy. We put alot of expectation on drivers to be reasonable when driving around on side streets.
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  14. #14
    Cyburbian
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    Mattoon has yet to figure out that salt melts ice/snow. They spread sand on the major intersections and only plow over 4 inches. I like it when it warms up and gets slushy, then freezes hard overnite and there are 4" ruts of ice in the roads. The good thing is that seems to slow the drivers down.

  15. #15
    Cyburbian
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    Salt, Bridges, and Wisconsin

    dobopoq,
    I haven't really noticed whether the salt levels have been increased or not over the last several years, although I do agree that they put down alot, especially Baltimore County and City. There was a blurb in a recent issue of Natural History magazine (December/January or February, I think) on a newly published study by a local researcher of road salt and salinity in Baltimore streams. The upshot is that the streams around here have higher salt levels than they used to, and the increase has accelerated in the last decade or two.
    There was also an article earlier this winter, in either Popular Science or Natural History (I don't have them on hand at the moment) on a newly replaced bridge in Wisconsin that had some new design features to increase durability and extend its operational life. The only feature I remember clearly was the semi-porous paving material. WDOT (or whoever it is that plows and salts the roads there) was using a chemical that contains magnesium and may be the one Cardinal mentioned. The benefit of that feature was that the paving material retains the chemical in its pores for weeks or months at a time, so that it meltssnow and prevents ice for longer with fewer applications and less of the chemical washing away in runoff, cutting both costs and pollution. This article came the month after the salinity study, and I thought then that maybe Wisconsin had hit on a solution to Maryland's costly salting program and stream salinity.

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    Cyburbian
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    This is a pet peeve of mine. . . in Eastern Washington and Idaho they have very poor snow removal and do not use salt. Prior to a storm they use "Chemical deicer treatment" which I was told my an auto body guy is worse on cars than salt becuase it sticks to them better. . .they also plow but with such a low level of service that most residential streets (I am talking about urban areas here) do not get plowed at all. The roads stay pretty bad until it rains.

    Consequently their is widespread use of studded tires and in mountainous areas chains. . . and we have these huge rutts in the road that people like blame on tractor trailers. . .

    ug.

  17. #17
    Cyburbian dobopoq's avatar
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    Quote Originally posted by B'lieve
    dobopoq,
    I haven't really noticed whether the salt levels have been increased or not over the last several years, although I do agree that they put down alot, especially Baltimore County and City. There was a blurb in a recent issue of Natural History magazine (December/January or February, I think) on a newly published study by a local researcher of road salt and salinity in Baltimore streams. The upshot is that the streams around here have higher salt levels than they used to, and the increase has accelerated in the last decade or two.
    There was also an article earlier this winter, in either Popular Science or Natural History (I don't have them on hand at the moment) on a newly replaced bridge in Wisconsin that had some new design features to increase durability and extend its operational life. The only feature I remember clearly was the semi-porous paving material. WDOT (or whoever it is that plows and salts the roads there) was using a chemical that contains magnesium and may be the one Cardinal mentioned. The benefit of that feature was that the paving material retains the chemical in its pores for weeks or months at a time, so that it meltssnow and prevents ice for longer with fewer applications and less of the chemical washing away in runoff, cutting both costs and pollution. This article came the month after the salinity study, and I thought then that maybe Wisconsin had hit on a solution to Maryland's costly salting program and stream salinity.
    A belated thanks B'lieve. Baltimore does seem to use an awful lot of salt. I guess chemical and paving advances are a good thing. At least somebody in WDOT seems to be giving a few cents of thought to the potential consequences of all that salt.
    "The current American way of life is founded not just on motor transportation but on the religion of the motorcar, and the sacrifices that people are prepared to make for this religion stand outside the realm of rational criticism." -Lewis Mumford

  18. #18
    Cyburbian
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    chaos in montreal

    ever since the municipalities of the island of montreal have been merged into a mega-city, snow clearing in each "borough" (arrondissement) is undertaken independently. major arteries and bus routes are always cleared within 24 hours of a large snowfall (30+ cm), but sidewalks and side streets downtown have been left uncleared and icy for several days. snow is removed at an equal pace throughout the city.

    prior to the merger, downtown streets were cleared with priority. today pedestrians downtown feel threatened by sloping streets covered in sheet ice. the locals have adapted, mostly by staying in the underground city if possible. it is extremely treacherous.

    on the subject of the salt/gravel used to remove ice, the quebec rule is salt if the temperature is above -15C....soooooo much salt. and a gravel/chemical aggregate used below that. sand is rarely used here.

    quebec probably has the worst roads in north america.

  19. #19
    Cyburbian njm's avatar
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    Quote Originally posted by B'lieve
    dobopoq,
    There was also an article earlier this winter, in either Popular Science or Natural History (I don't have them on hand at the moment) on a newly replaced bridge in Wisconsin that had some new design features to increase durability and extend its operational life. The only feature I remember clearly was the semi-porous paving material. WDOT (or whoever it is that plows and salts the roads there) was using a chemical that contains magnesium and may be the one Cardinal mentioned. The benefit of that feature was that the paving material retains the chemical in its pores for weeks or months at a time, so that it meltssnow and prevents ice for longer with fewer applications and less of the chemical washing away in runoff, cutting both costs and pollution. This article came the month after the salinity study, and I thought then that maybe Wisconsin had hit on a solution to Maryland's costly salting program and stream salinity.
    Minnesota will be trying this as well. The chemical was actually developed privately (by Monsanto, I believe.)

    Most Swedish cities use coarse sand (some of) which is swept up, washed, and reused the next winter. There's always some lost into waterways either due to removal of the snow (Stockholm dumps inner-city snow into Lake Mälar) or runoff. The sand is made of crushed granite, so it is usually angular enough to aid traction. It has to be re-applied frequently if the streets have snowpack, though, as it tends to be forced into the pack by traffic.

    Vägverket (the national road administration) uses chemical melters on the primary inter- and intra-city arterials (European Highways and major national highways.)
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  20. #20
    Cyburbian jresta's avatar
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    In Philly we've been averaging 3-4 snow events a year. One usually is a foot or more of snow, one around 4-6 inches, and the other two an inch or so.

    The city hooks plows on to the front of the garbage truck fleet. We have different sized trucks depending on the neighborhood. A lot of streets here have a cartway of 6 ft. or less.

    The narrow streets normally just get plowed (some don't get plowed at all) and don't see any salt or sand. The major arteries get a mixture of salt and sand and i've noticed the pre-wetting on the expressways and suburban arteries.

    When we have a major snowfall a lot of the snow, especially in Center City, has to be taken off-site. Cities here can't dump their snow in the river since, by the time it gets plowed and scooped up it's normally heavily contaminated with the normal road surface mix, and often a heavy dose of salt as well. So they've bought a few melters (which are really just giant toaster ovens) and they dump snow in them. The melter then sends the water to the nearest storm drain.

    Some of the snow is sent to melt naturally on unused lots down by the navy yards.
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    Cyburbian zman's avatar
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    In Colorado, or at least my county, we see the Magnesium Chorlide (pre-deicer) placed on the roads when snow is predicted.
    I think that this chemical does more damage to a car than salt (or so I have heard).
    We also use gravel. I have never seen salt used, but I could be wrong.

    As far as the environmental effects, the gravel that remains on the roads of Metro Denver after the snow melt accounts for much of the winter brown cloud that surrounds much of the city by way of an inversion layer.

    A regional difference in planning for snow removal became apparent last winter. We had an application for a car dealership and their architect was from the Boise, ID area. He had phoned to ask how many extras parking spaces were needed in order to accomodate plowed snow piles for the winter.
    The snow melts too quickly in the urban cooridor for Colorado, but this was an interesting concept. Extra area given for the storage of snow "in the melting process".
    Last edited by zman; 24 May 2006 at 12:17 PM.
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  22. #22

    Here's what we use (Caliber M-1000)

    It's a combo of Magnesium Chloride and a special ingredient. Thus, it is environmentally friendly and about as corrosive as water...Here's the specs.

    http://www.anti-icers.com/m1000_perf...properties.htm

    Salt good down to 18 degrees, salt treated w/caliber good to -25 degrees. Effective on ice and packed snow.
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  23. #23
    Cyburbian
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    Quote Originally posted by zmanPLAN
    A regional difference in planning for snow removal became apparent last winter. We had an application for a car dealership and their architect was from the Boise, ID area. He had phoned to ask how many extras parking spaces were needed in order to accomodate plowed snow piles for the winter.
    The snow melts too quickly in the urban cooridor for Colorado, but this was an interesting concept. Extra area given for the storage of snow "in the melting process".
    This is a common practice in my neck of the woods too. You got to have some place to push the snow so it can melt. We don't really require additional parking, just a plan as to where they plan to puch the snow to make sure it doesn't block the sidewalks, ramps, ada spots, etc.

  24. #24
         
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    Rural Minnesota

    At my school in Rural Minnesota, one Campus uses Salt and the other Sand. The reason for the division is the sand campus is on a many many many acres forest preserve and it's a bunch of old monks who don't want to "poison" it (even though our Gemini Lakes are two of the most toxic in the state). I find the salt to be much more effective as it A) melts the snow on contact, rather than sand which relies on the friction of people walking to do it B) doesn't stick as bad to your clothes or in your home C) doesn't make indoor/non snowy area extra slippery

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