Key elements of snow and ice control: safe roads, money and the environment

Kathleen Schaefer
Instructor, Circuit Training and Assistance Program
Minnesota Department of Transportation
St. Paul, Minnesota

What are the key elements of snow and ice control? The traditional answer to that question has been balancing safe roads (meeting the level of service expected by the public) while staying within your budget. As though that's not enough, we now have another element that must be considered: protecting our lakes and rivers. It might seem that adding another consideration would hopelessly complicate our winter maintenance operations, but that doesn't have to be the case. In fact, measures taken to improve service and protect the environment can actually result in money saved.

At this year's Road Salt Symposium in St. Cloud, Minnesota, an annual event sponsored by the Minnesota Freshwater Society, Minnesota Local Technical Assistance Program and Fortin Environmental Consulting, Inc. environmental leadership awards were given to agencies that have successfully managed to maintain safe roads, reduce costs and protect the environment.

Ramsey County Public Works Department
In October of 2003, Ramsey County Public Works moved to a new state-of-the-art facility in Arden Hills, Minnesota. The old facility had very limited covered storage space; less than 1/8 of the total annual salt and sand could be stored inside. Prior to 2003, the County also applied sand mixed with salt to roadways. In earlier years, an 80% sand, 20% salt mix was used. This was changed to a 50/50 mix in the late 1990s. Using the salt/sand mixture required the hauling of additional thousands of tons of sand each year, anywhere from 8,000 tons to 20,000 tons depending on the salt/sand percentage.

The County's new facility now has two covered storage buildings. Presently about half the space is used for salt (NaCl) storage; the remainder is available for other materials as needed. This includes a limited amount of sand as well as ice-melting products that are being used on a trial basis to determine costs and benefits of alternative materials.

With the move to the new facility, the decision was also made to move from a sand/salt mixture to use of 100% salt in most situations. In order to control costs and minimize environmental impacts of salt, a careful program to calibrate all truck material spreaders was begun in 2005 and 2006 (30 trucks). With the change of material, all crews were trained on the importance of lower application rates. Most of the truck operators were closely involved with the calibration operations, so they would understand the procedure and would buy into the intent of the program.

Two years of experience has shown a number of significant advantages to the move to 100% salt along with the calibration program. The elimination of most sand use has greatly reduced spring road sweeping, and pavement markings last much longer and are more visible during winter and spring months.

Preliminary results show that the amount of salt used per lane mile, per event, has not increased, while the amount of sand used has decreased to near zero. Besides the benefits discussed above, the wear and tear on plow trucks has decreased because of the reduction in materials hauled and spread.

Ramsey County plans to continue their annual calibration program while looking for further improvements in materials and equipment. They consider their efforts a success as they continue to provide high-quality public service while controlling costs and mitigating environmental impacts.

University of Minnesota Duluth Facilities Management
The campus of the University of Minnesota Duluth covers 270 acres and is divided by two watersheds, Oregon Creek and West Tischer Creek (Tischer Creek is a trout stream). UMD has sought out training and enthusiastically participated in reviewing both equipment and methods to determine how salt could be reduced while still providing safe sidewalks, streets and parking lots on campus.

UMD has worked hard to redesign and calibrate equipment to apply salt at much lower rates. They altered methods to include more mechanical snow removal in order to reduce salt usage. Sidewalks are now swept after plowing to remove even more snow, which has resulted in a reduction in deicers. UMD has also adopted proactive methods such as anti-icing.

Prior to 2001, UMD used an 80% sand, 20% salt mixture. Between 2001 and 2003, they reversed the ratio to an 80% salt, 20% sand mixture. In 2004, they began applying 100% salt, pre-wetted with Caliber M2000 to the streets, parking lots and sidewalks. That same year, they also began an anti-icing program using Caliber M1000.

These changes have resulted in a dramatic reduction in the amount of deicers applied. In previous years, the average amount of NaCl used was about 550 tons of pre-wetted salt and 100 tons of MgCl. During the winter of 2006-2007, crews applied 180 tons NaCl and 18 tons MgCl, well over a 50% reduction in deicers.

Safety and lawsuits were the driving factors for using so much salt in the past, but they found the campus to be just as safe even with the lower rates. In addition to reducing salt in stormwater runoff, UMD Facilities Management is working to reduce salt damage to trees and vegetation on the campus.

City of St. Cloud, Minnesota
The City of St. Cloud Public Works Department maintains a proactive winter maintenance program. Prior to 2003, the City used an average of 10,000 tons of a 50/50 salt-sand mixture per year. The cost of spreading this material and sweeping it up, not to mention the amount that went into storm drain systems and rivers, was a driving factor toward change. Since 2003, the City has switched almost exclusively to 100% salt. To reduce their application rates, they calibrate their sanders at least once a year with a goal of 300-400 pounds per lane mile.

Over ten years ago, St. Cloud realized wet salt worked much better than dry salt, so they developed their own homemade brine-making system and equipped most trucks with onboard pre-wetting systems. In 2003, the City added a large anti-icing tank to its fleet for spraying bridge decks, arterial roads and hazardous areas. The results were great; there were no callouts for bridge deicing, and they saw less bonding of snow and ice to roads and fewer accidents at curves. With the demonstration of these benefits, the City was able to add an Epoke, a specialized sander/anti-icing and pre-wetting truck to their fleet. With this unit, the City can closely track the amount of salt and liquid applied. St. Cloud has reduced their usage of aggregate sand by 50% or more, and has reduced their salt usage by 850 tons, a 33% reduction.

Crews attend winter maintenance training classes, and stay up-to-date on the latest advances in winter maintenance. The motto "more is better" has been put to rest through detailed training on application rates along with the help of good field results, a culture of inclusiveness, and teamwork.

University of Minnesota, Twin Cities Campus
Over the past few years, the University of Minnesota recognized the need to become much more environmentally conscious with regards to winter maintenance, stormwater management and the campus environment.

In 2005-2006, they implemented many changes in their snow removal program. Two key areas were employee training and calibration of equipment. By increasing awareness of proper application rates, they were able to significantly reduce the amount of deicing chemicals used.

In 2006-2007, they started an aggressive anti-icing program with liquid magnesium chloride for sidewalks and salt brine for the streets and loading docks. The pre-storm applications were extremely successful in reducing the bond of snow and ice to walks, as well as affording an increase in response time on the front end of snow events. Mechanical removal of snow was also stressed over the "burn-it-off" approach. The university dramatically reduced the use of sand which saved time and money in spring cleanup, and long-term savings are expected in storm sewer maintenance. Small amounts of sand are still used as pattern indicators for sidewalk trucks and for use during extreme cold weather.

Due to the changes from 2005 to 2006, the university saw a total material reduction of 985 tons:

  • Rock salt usage went from 912 tons to 295 tons, with a net reduction of 68% and a savings of $29,881.
  • Magnesium chloride usage went from 123 tons to 43 tons, with a net reduction of 65% and a savings of $32,800.
  • Sand usage went from 313 tons to 25 tons, with a net reduction of 92% and a savings of $2,390.

The total material savings was $65,071; with an investment in equipment of $10,000, the university saw a net savings of $55,071.

The numbers speak for themselves; through a combination of calibration, training, anti-icing and pre-wetting, along with an attitude accepting of new ideas and changes, an agency can do all three: maintain safe roads, save money and protect the environment.

Kathleen Schaefer can be reached at (651) 282-2160 or kathleen.schaefer@dot.state.mn.us.