Water

Cold Weather Stormwater Management

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As the winter season commences, stormwater management shifts to cold weather practices in much of the US. It brings inherent challenges, especially the effects of deicing salt, sand, and chemicals and concerns about runoff into nearby water bodies.

There is also concern about the effect of freeze/thaw cycles on permeable pavements, including potential damage to the pavers or pavement itself, as some tend to have more open space than traditional asphalt. Sometimes snowplow blades can damage the surface or displace individual pavers. On the other hand, because water does not stand for long periods on the surface, there tends to be less ice buildup than on traditional pavement.

The effects of cold weather on other green infrastructure such as bioswales and engineered wetlands can influence planting choices, such as opting for salt-tolerant species. And many cities limit or suspend their street sweeping programs during the winter because it’s difficult or impossible to operate the sweepers in snow and ice.

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Fairbanks, AK
Fewer places face more severe stormwater management challenges from snow and freezing temperatures than Fairbanks, AK.

While winter temperature averages are trending upward, temperatures here can dip as low as 50°F below zero in January and February, says Andrew Ackerman, environmental manager for the City of Fairbanks. He adds that the low temps are due to the lack of sunlight between November and early March and that it is a dry cold.

The region can get an average annual snowfall of 65 inches, according to US Climate Data.

The city of Fairbanks—with a population of fewer than 35,000 people—is the main urban core area in the overall metropolitan area of the Fairbanks North Star Borough, which has a population fewer than 100,000.

Most of the area is covered by an MS4 storm sewer permit, says Ackerman, adding that as part of its MS4 permit, the region also collaborates with the Alaska Department of Transportation and the City of North Pole and partners with the University of Alaska Fairbanks.

There is continuous permafrost in some areas of the city that can reach a meter below the surface, he says.

“Other areas of Fairbanks have discontinuous permafrost, so there may be a meter or so of soils and then you hit a permafrost lens, and may go down and hit another lens, depending on what part of town you’re in,” says Ackerman.

The spring brings a freeze/thaw.

“We get melting,” he says. “Even if we had a rain event on top of an initial warm-up event with some melting or rain, there is not much percolation because of the frozen ground, so there is a lot of horizontal runoff. Our storm drains are basically the only thing that keeps everything from flooding.”

The metropolitan area storm sewer system includes nearly 100 miles of storm drain infrastructure within the city, which has more than 2,500 drain inlets.

Fairbanks has implemented some green infrastructure and stormwater detention, “but for the most part, it’s hard to design those types of facilities so that they allow a slow percolation into the groundwater at a steady flow because we have such variable soils and permafrost,” says Ackerman.

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On the main arterial road of Cushman Street, which runs through the downtown urban core, city workers recently installed tree wells: areas of loose snow around a tree trunk enclosed in deep snow. Ackerman notes there is a grate on the surface that allows water to drop down into the tree well.

The city also has used small grants to help local businesses install permeable pavers.

“Each year, we have given out a few rain barrels to local businesses or private property owners,” says Ackerman. “We have re-engineered some of our park areas downtown along the river such that rather than having stormwater being directed into the river, we use some inlets to drop the water to a catch basin and a Stormceptor before going into the river. That filters out some of the petroleum products and fines before allowing the water to then pass into our storm sewer system.”

“Our public works department does a lot of maintenance on the system. They do continuous spring sweeping of the system and then respond to any illicit discharges or potential spills. We then collaborate with the Alaska Department of Environmental Conservation spill response staff.”

The Fairbanks North Pole stormwater management program requires best management practices to prevent erosion on new construction for projects exceeding an acre.

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“Here in the city limits, we have a stricter threshold; for anything over 10,000 square feet resulting in a ground disturbance, we enter a review and require best management practices,” notes Ackerman.

Other efforts are put forth by the Tier 1 Center for Environmentally Sustainable Transportation in Cold Climates, a consortium of three universities, led by the University of Alaska Fairbanks and including Montana State University and Washington State University. The consortium provides multidisciplinary research, education, and technology transfer focused on transportation issues for environmental sustainability.

The organization’s research site includes a section on completed and ongoing studies in managing stormwater runoff in cold climates through improved training, monitoring, advanced technology, and pervious concrete. (See www.cem.uaf.edu/cesticc/research.aspx.)

Recently, the consortium has been testing various deicers.

“One of the things we are challenged with here in Fairbanks is that it gets so cold that traditional salt brines or sodium chloride salt don’t really perform that well,” says Ackerman. “We are not using a lot of salt. We put down sand or we try to scarify the snow or the ice so there is a little more traction.”

While the city is not applying salt or salt brine, the state’s transportation department—which is responsible for the larger arterials and highways in or around Fairbanks—does use salt brine mix, he adds.

“They are looking at it because it’s very corrosive,” he says. “It impacts the machinery and the trucks. They’re looking at different types of mixes using organics or potassium.”

While some stormwater management practices are unique to Alaska, the state’s research on various methodologies may prove useful elsewhere, says Ackerman.

Case in point: work with cryoprotectants, which change the temperature at which something freezes.

Alaska’s cold climate brings on a number of pressing issues in stormwater management.

“We have challenges associated with putting in green infrastructure like permeable pavement because of the way that material behaves in really cold temperatures and also because of the subsurface—the geologies, soils, and the permafrost,” says Ackerman. “It doesn’t perform as well as it would even in some of the northern latitudes in the lower 48.”

He continues, “We don’t have as much flexibility with implementing some green infrastructures. We can implement a lot of green infrastructure elements within a typical right of way with sidewalks and typical roadway. We even have put aboveground planters along roadways.”

“There’s the general challenge from the standpoint of how we develop in cold climates and in northern latitudes in general,” says Ackerman. “It’s more expensive to implement some of these things and bring in supplies.”

Ackerman cites what he calls a “cultural attitude” that comes with living in a remote part of the US.

“There may not be as much of a proactive approach to implementing some of these green strategies,” he says. “Even though it’s a social issue, it’s pretty real as far as getting support. We’ve done quite a lot working internally with our partner agencies, but we also have some partners in the nonprofit world that have helped us to implement some of our green strategies and projects here in Fairbanks.”

Effective cold weather stormwater management is actually a year-round effort, notes Ackerman.

Case in point: spill response. “There has been a big push in the last couple of years where we have been doing more trainings with our public works staff in trying to get to the spills quicker and report them quicker,” says Ackerman.

Public outreach is a strength in Fairbanks as the city collaborates through its MS4 program with other entities, he says.

“We do a storm drain art contest and we pick a street in Fairbanks where we allow 10 to 12 artists to go out and paint the storm drains with a message about not polluting,” he says. “They have become very visible, and they’re a great way of bringing attention to the fact that our storm drain and storm sewer system is connected directly to the river and it does not go to our sewage treatment plant.”

Additionally, the city hosts a stream cleanup event on a June weekend that attracts up to 40 volunteers. The group collected more than 900 pounds of garbage this year.

Fairbanks puts street sweeping on hold for the winter.

“It’s all about shoveling and snowplowing,” says Ackerman. “If we get a lot of snow in a short period of time, we push the snow to the edge of the roadway just to make it so vehicles can get through. We also have smaller equipment to plow or the brush mechanism on the front of smaller Bobcats that can brush off snow from the sidewalks.

“In the springtime, after the snow melts and there is a lot of gravel or sand on the roadways, then we get the sweepers out and they go around to try to get everything as clean as possible.”

Philadelphia, PA
Meanwhile, in the densely populated northeast region of the US, cities like Philadelphia, PA, grapple on an ongoing basis with the best approach to cold weather stormwater management.

According to US Climate Data, the average annual snowfall in Philadelphia is 23 inches, with the annual low temperature being 47°F.

The city of Philadelphia’s current detailed snow and ice operations plan points out that Philadelphia is like other northeastern US cities in that it often faces winter storms that bring potentially dangerous accumulations of ice, sleet, freezing rain, and snow.

Philadelphia’s geographic position contributes substantially to forecasting uncertainties, with the mountains to the west and the Atlantic Ocean to the east. The March 1993 blizzard was originally forecasted as a 3-inch storm, but it mushroomed into a major storm bringing upward of 12 inches, including sleet and freezing rain. Two other snowstorms in subsequent years also brought on surprises, necessitating flexibility in planning and response.

The city’s wastewater system currently serves the city of Philadelphia and parts of Bucks, Montgomery, and Delaware counties with a total service area population of approximately 2.3 million, including approximately 1.5 million living within the city and some 750,000 residents in outlying municipalities. The service area population is distributed over 364 square miles, with 230 square miles in suburban communities and 134 square miles in the city, notes Marc J. Cammarata, deputy commissioner for the Philadelphia Water Department, Planning and Environmental Services Division.

The wastewater collection system consists of approximately 3,714 miles of collector system piping. Of the 19 pumping stations, 16 are owned by the water department and three by others.

The system also includes 94,293 manholes, 25 storm relief structures, and 71,926 stormwater inlets. There are approximately 763 miles of sanitary, 740 miles of stormwater, and 1,852 miles of combined sanitary/stormwater mains.

Sewers range from 8-inch-diameter pipes to 21- by 24-foot arch-shaped conduits primarily constructed of brick, vitrified clay, or reinforced concrete. The wastewater system consists of three drainage districts, each served by a treatment plant, says Cammarata.

The use of road salt across Philadelphia’s watershed during the winter results in readily noticed water-quality changes, he says. When road salt reaches the rivers, there is an increase in the conductivity of the water—a measure of the water’s ability to carry an electrical current.

“As road salt washes into the river, we can track the increase in conductivity,” he says. “This increase is largely due to sodium chloride, a common form of salt used for deicing the roadways. Therefore, the sodium and chloride levels in water increase during this time. These events are typically short-lived, lasting a day or several days at a time.”

Philadelphia is currently developing salt and deicing best management practices (BMPs) for salt storage and handling on municipal sites as part of a municipal good housekeeping program. The BMPs outline pollution prevention practices that will reduce stormwater runoff containing salt from municipal sites, says Cammarata.

In the winter of 2008, Philadelphia Water Department (PWD) began accepting used aircraft deicer fluid (ADF) from the Philadelphia International Airport to feed the anaerobic digesters at its Southwest Water Pollution Control Plant. The addition of ADF increases the production of energy-rich methane gas that PWD can use to decrease fossil fuel consumption, thereby reducing the department’s dependence on non-renewable energy sources, says Cammarata.

“It’s a unique resource recovery-related project,” he says.

Credit: iStock/Modfos

The city’s snow and ice operations plan prioritizes routes, indicates the appropriate distribution of resources, and identifies the duties and responsibilities of all city employees enlisted in the response. It accommodates uncertainties in planning as well as operations. City agencies work in concert to clear and make safe more than 2,500 miles of streets and roadways to enable businesses and city agencies to maintain normal operations during most weather events.

The city’s streets are divided into primary, secondary, and tertiary route systems, including 25 miles of private streets where residents contract for private snow removal. When a snow emergency is declared, primary routes are the first priority, followed by the rest.

Some 148 primary and secondary route systems are salted as soon as significant moisture has accumulated on roadways to minimize potentially dangerous travel conditions. Plowing begins when there is such a sufficient buildup of snow that salting is no longer effective.

The city’s response is based on the number of inches of snow that fall. Partial clearing is conducted on higher terrain when 1 to 5 inches fall, and a full deployment for 135 routes is executed when snowfall exceeds 5 inches.

The responsibility for maintaining the roadways during winter storms is shared among the Pennsylvania Department of Transportation (PennDOT), the Fairmount Park Commission, and the Philadelphia Streets Department, which serves as the primary response agency for anti-icing and deicing events.

Of the 360 miles of state roads, PennDOT maintains 50 miles of limited-access state highways, including I-95 and I-76, and contracts the remaining 310 state miles with the city for snow and ice removal for a total of 2,525 miles of city and state roads that the city maintains.

The Fairmount Park Commission removes snow and ice from 35 miles of park roads, with snow and ice removal on the remaining 2,490 miles of city streets being the responsibility of the Streets Department.

In storms of large accumulation, the Sanitation Division is mobilized to supplement the snow removal effort with vehicles outfitted with plows, with supplemental services from private contractors.

The city’s operations phase begins when the forecast is for temperatures consistent with snow, ice, sleet, or freezing rain, with at least a 50% chance of precipitation.

Salting operations begin once the storm arrives and falling precipitation creates icy or snow-covered streets. Certain roads may also be pretreated with salt brine as conditions warrant so snow does not bind to the roadway, although for pre-storm forecasts of rain to snow, brine is not pre-applied if it is apparent it will wash away.

Additionally, some trucks are equipped with a pre-wet system that brines the salt before it is spread. Salt trucks are deployed to cover the route structure, and salting continues until it is no longer necessary or has become ineffective.

Salt, a brine solution, or sand and other abrasives are used to help clear the roads. The salt brine is a liquid containing a 23% sodium chloride solution applied at rates of 30 gallons per lane mile in an effort to effectively melt the first 2 inches of snow before reapplication is necessary.

The time of the year affects the department’s winter storm response. In the late fall and early spring months when temperatures are warmer, the city might use only salt to address a 4- to 5-inch accumulation. In colder months, plowing is necessary. Low temperatures increase the amount of salt necessary to melt off precipitation. Stronger winds can hamper snow-fighting efforts by spreading snow across cleared roadways.

The city’s Highway Division endeavors to maximize every application of deicing salt to maintain the safest roads possible in the most economical way while protecting the environment. Procedures include training personnel in salt application, updating or replacing equipment as needed, properly calibrating the spreaders, using automatic controls to ensure correct amounts are being applied, adequately covering storage areas, and using proper maintenance procedures around storage areas.

The city’s plan points out that salt and deicing materials should be used in a manner that safeguards the environment. If misused or improperly stored, deicing materials can get into wells or groundwater. Excessive salt use can be damaging to certain plants and trees when runoff leaves sodium chloride in the soil.

The application of salt alone depends on the type of precipitation, temperature, and snowfall intensity. When there is adequate frozen precipitation on the pavement at a non-plowable depth and the temperature is above 25°F, straight salt is used. When temperatures dip lower, a mixture of salt and abrasives is used.

The initial treatment of the roadway before plowing operations begin is to reduce ice or snow bonding to the pavement. Salt application rates range from 200 to 800 pounds per two-lane mile depending on the storm conditions.

Salt can be applied in a windrow or full width. Plowing operations are timed to allow maximum melting. Salt reaction time is usually 20 to 30 minutes, with reaction time increasing as temperature decreases.

Spreaders including tailgate and V-box spreaders are used to apply salt or sand. Application rates are set for various conditions following Salt Institute guidelines.

Snow removal equipment—including the pre-wet system—is cleaned following each storm, with spreaders and plows removed.

Because the Streets Division’s fleet inventory for snow operations is aging, the department has set up lease agreements to provide supplemental equipment for large and residential streets to ensure reliable operations.

The salt inventory is dictated by storage capacity, including salt domes at secure satellite locations citywide; availability of product; and environmental concerns. The city has the capacity to store more than 50,000 tons of salt. Anti-skid material may be added to the salt if the inventory starts to run low or if the temperatures is so cold that the salt might not be as effective.

The city has design details and standards that account for the impact of freeze/thaw with regard to stone layers and geomembranes, says Cammarata.

Because Philadelphia gets its share of cold weather and snow, “a lot of the vegetation we use goes dormant, and snow getting dumped onto it sometimes damages it,” he says. “We replant it the next year either because of damage from the snow or people treading through some of our surface-based practices. We try to use salt-tolerant species that are OK in this climate. We have no history of what 20 or 30 years of salt application will do to our vegetation and our practices yet. They’re not out there long enough.”

Philadelphia contracts out its snowplowing on permeable streets, says Cammarata. Philadelphia Water’s Green Infrastructure Maintenance Manual sets forth procedures for pervious pavement winter maintenance that indicate snow piles containing sand cannot be stored on pervious pavement and that all deicers used in the rights of way (ROWs) must be approved by the owner/operator and be PennDOT-approved products.

Deicer is applied as a pre- and post-treatment for every snow event greater than 0.25 inch, for sleet and freezing rain events, and after every plowing event.

Sodium formate is applied at a rate of 10 pounds per 1,000 feet for all non-ROW pervious pavement and all non-ROW pervious concrete constructed in the previous two years.

Calcium chloride is applied in flake form at a rate of 21 pounds per 1,000 feet for all pervious pavement in the ROW constructed in the last two years.

Pervious pavement is plowed for snow events with snow accumulation of more than 2 inches. The rubber plow blade is to be raised to a half-inch above the surface.

Des Moines, IA
When snow systems move across the midwestern US, communities such as Des Moines, IA, put into action cold weather stormwater management plans.

The average annual snowfall in Des Moines is 35 inches, with an annual low temperature of 41.4°F, according to US Climate Data. Some 215,000 residents live in 82.6 square miles in Des Moines.

As is the case with other municipal entities, roadway agencies are always looking for ways to economize and have been aggressively seeking to reduce salt consumption with one eye on the environment and another eye on the bottom line, notes Jonathan Gano, Des Moines’ public works director.

“An excellent technique in many snow-fighting agencies’ playbook is to pre-treat the roads with a spray of salt brine ahead of the event,” he says. “The salt brine is a very dilute mixture of water and salt that lets the overall salt application before and after be markedly reduced from what a traditional snowplow-mounted rock salt spreader would need to achieve the same results.”

In Des Moines, the effect of freeze/thaw on permeable pavement is negligible “as there is plenty of open-air space for residual moisture to expand into upon freezing,” says Gano. “A properly designed, maintained, and functioning installation of green infrastructure will not be holding water longer than 24 hours, which under most circumstances is enough time to drain down before freezing temps can penetrate through the soil.”

At one time, Des Moines’ Public Works Department parked street sweepers once temperatures stayed below freezing and wouldn’t start sweeping until the temperatures permitted, usually mid-November until March, says Craig Shepherd, public works section chief. But that has changed. “We now have six new waterless sweepers that allow us to sweep year-round,” he says of the addition of Elgin waterless street sweepers to the fleet. “We can sweep traction material after a storm to prevent it from becoming dust, and we are able to get to the trash and debris in the gutter line sooner.

“We also find that without having to stop for water refills, we are getting our curb lane miles swept much quicker and capturing more of the fugitive dust that used to get weighted down by the water.”

Aberdeen, SD
Robin Bobzien, public works director and city engineer for Aberdeen, SD, says his department has several factors to consider in managing stormwater for a community of fewer than 30,000 residents. The average snowfall here can be in the 3-foot range, he says. The annual low temperature is 31.5°F, according to US Climate Data.

“A huge consideration for us is in trying to determine what types of potential flooding we could end up with, and those would be likely significantly different than a big 8-inch, 24-hour-period rain,” he says. “Typically, most of our designs are driven by that 8-inch-type flood event, and we can end up with some interesting things due to the cold weather. We could end up with several feet of ice that we’re dealing with in our channels. We could end up with surges of water coming through where the ice is preventing actual flow through the channels.”

Bobzien says Aberdeen has a 4-foot trough level, which is significantly less than in towns farther north. With shallower storms, he says, “It can be a real problem because they’ll gradually ice up and they won’t convey anything when we need them to when the spring operation is coming.”

Bobzien’s department handles everything within the city limits, including state highways that run through town.

Aberdeen, not unlike Fargo and Grand Forks, has very flat grades, “so stormwater capacities become a huge problem for us. Your pipes are not going to have the slopes that sometimes are required for good conveyance,” says Bobzien.

“We do not use any sand for deicing, because the sands will end up affecting our capacity over time,” he adds. “We’re using straight salt for our deicing processes. We found that we are not going back multiple times over the course of an event once we apply it. Our operators can move on to something else for the night.”

Bobzien says the city’s Public Works Department has the option of using some pre-wetting solutions, an approach crews resort to only infrequently. “One problem is there are winds in this part of the country that oftentimes will blow the snow back over the top of stuff we’re melting, and it ends up actually making ice. It becomes a unique situation for us because we can start the process and it will eventually undo itself and it just makes more ice instead of dealing with the little bit that we have.”

Aberdeen uses a traditional salt mix on the roads “primarily because of the equipment we have available right now,” says Bobzien. “We’re going to be exploring some equipment purchases that would give us additional capabilities in dealing with it in a different manner.”

Aberdeen has not installed permeable pavement. “As harsh as our temperatures can be, I’m having trouble with the concept of wanting moisture to enter the pavement and letting it freeze,” says Bobzien. “I know some places have done it successfully, but we’re going to stand back and see if the test of time works for those pavements because while they appear to be working, I don’t know about long-term additional maintenance.”

Aberdeen has a weekly sweeping program. “We want to keep as much of that debris picked up on a weekly basis as we can so we don’t end up with it down in our storm sewers and entering streams, which over time affects our capacity for managing stormwater,” he says.

Aberdeen has 80 miles of storm pipe ranging from 18 to 96 inches, several ditches, and 10 miles of conveyance channels.

Bobzien says many upper Midwest stormwater managers and public works managers will gather to share ideas on stormwater management. “I love going into roundtables where I’m able to hear a number of different folks speak on their challenges,” he says. “Usually it’s topic-specific, and we end up with three or four communities that have a different approach.

“Sometimes you can come out with a lot of great ideas that will help your community by picking the brains of others who have tried and sometimes failed, and they come up with a better method after they have goofed up a couple of times.”

Credit: iStock/ookinate23

More Than One Approach
Steve Bytnar, vice president of research and quality for EnviroTech Services, says there are several ways entities can approach deicing practices.

“Our primary focus on winter road maintenance is the use of products and training to teach folks how to use less to achieve better deicing and better results, providing safer roads by using less product,” says Bytnar.

One approach is the use of products on the market that are developed to be higher performing—they’ll melt more snow and ice when applied on the road and less product is needed, says Bytnar.

“The other part of that is modifying some of the existing products like road salt,” he says. “There are products available that if you coat the salt, you can reduce your salt applications by 30 to 50%—not because it makes the salt melt any better, but because it sticks it on the road and prevents the bounce and scatter.”

Bytnar says a number of studies dating back to the 1990s show that when salt is applied to the road, within the first five or six passes, up to 80% of the salt is off of the road and on the shoulder and the borrow ditch, “which isn’t doing any good. We modify that by putting materials on it that stick it to the roads so the traffic doesn’t remove it from the road surface. That’s one of the quickest and easiest ways to do it. You can reduce your salt applications by 30 to 50% just by doing that.”

EnviroTech employs former transportation department and public works employees to conduct training tours for those looking for strategies to maximize deicing efficiencies, says Bytnar. While part of the program entails education on how to use less product, it also includes information on how to schedule routes in order to use less, he says.

“You might have to go out one more time on a route, but if you apply 200 pounds per lane mile twice, that’s better than 600 pounds once,” Bytnar says.

EnviroTech Services uses sensors in its lab research to measure the roadway friction and temperature. They are fixed in place. The company also uses sensors attached to vehicles to gather field data.

“You can drive the roads and determine the amount of ice and snow on them,” he says. “You can determine the temperature of the road and then use that as a guiding principle. Maybe you can spread 80 gallons per lane mile of liquid deicer in contrast to the typical 120 gallons. You can use this as a decision-making tool so as to not overapply.”

Bytnar points out that when the sun comes out after a storm passes and the road dries and turns white, that is salt residue—indicating there was too much of it applied on the road.

EnviroTech Services provides a range of deicing and anti-icing products. Choosing the appropriate product begins with establishing goals, says Bytnar.

“How cold of temperatures do they really get? What are the average snowfalls? What are their goals? What is their policy? Some folks just want to get a layer of anti-icing down. They do what they can. They plow a lot, but they’re really waiting for the weather to break and the temperatures to warm up before the roads really get clear again.”

Some municipalities such as in Denver have a wet-road policy. “When they go out to work on the primary roads, their goal is to never let them snowpack. They do whatever they can to prevent that from happening. Denver International Airport is the same way,” says Bytnar. “We joke here a lot that planes might not be leaving the airport because of a snowstorm, but you can get to the airport.”

Another consideration is whether a municipality has multiple storage tanks that can hold different products as opposed to being constrained to using one product because of limited storage. EnviroTech Services customizes a program for end-users that enables them to make the best decision based on available options, he says.

For cities near water bodies, the company focuses on the use of its high-performance products because it doesn’t take as much to be effective, says Bytnar. For instance, Apex liquid deicer is designed to be high performance. MeltDown Apex is designed for a higher improvement in freeze point, with the performance-enhanced magnesium chloride (MgCl2) brine producing results at lower temperatures and improving the ability to combat snow and ice buildup on road surfaces. It can be used as a standalone product or blended with salt to expedite snow and ice melt and enhance traction.

“Depending on the temperature, it will melt 40 to 60% more snow and ice than standard mag chloride alone,” says Bytnar.

For those using dry materials, the company recommends the use of Ice Slicer granular ice melt, a homogenous product containing naturally occurring minerals such as complex chlorides, sulfur, iron, iodine, zinc, copper, manganese, phosphorous, and more than 50 trace minerals. Its red color absorbs more heat than white products and therefore speeds up ice melt, and it also alerts motorists that roads have been treated.

Another alternative is to use treated rock to reduce the bounce and scatter as it sticks to the road and doesn’t end up on the shoulder and in the ditch, says Bytnar.

“The key is to maintain as much product on the road for as long as possible,” he adds. “When you do that, it melts more snow and ice and you’re using less material. If you have less material melting more snow and ice, it’s significantly diluted to a much higher level.”

EnviroTech Services worked with Golden Valley, MN, to run a test on its products using friction sensors. Different products were placed on opposing lanes of the same stretch of road. The test enabled city employees to quickly figure out the products’ efficiencies and how they could lower their application rates, notes Bytnar.

“Anytime an entity has the time to get more data to make better decisions, we are big fans of that,” says Bytnar. “We’ve become big advocates for the use of the friction sensors so that they can gather as much data as possible to make good decisions.” SW_bug_web

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