Case Study # 5

Salt Reductions through a New Approach to Winter Maintenance Practices - Otterburn Park, Quebec

Overview

In the early 1990's, the Town Council for Otterburn Park became concerned with the amount of salt being used on its roads. To address this concern, the Town began a program to reduce its salt use. In the period from 1995 to 2000, Otterburn Park was successful in reducing its total salt use by 73% through improved training, better plowing practices and the use of pre-wetted salt.

Background

In the 1995-96 winter season, the Town of Otterburn Park used approximately 1,100 tonnes of salt to service approximately 30 km of road. The following graph shows the reduction in salt use that occurred over the subsequent four winter seasons as a result of the winter maintenance program introduced. These reductions were achieved despite the fact that the Town added an additional 20 km of roads to its system over the same period.

Description of Winter Maintenance Practices

Before the change in winter maintenance practices, the Town followed a traditional winter maintenance approach. All roads were salted and plowed as needed. Some of the plowing operations were contracted out, while the remaining were done in-house. The Town did not prioritize its road network, and therefore treated all roads equally. In addition, because the Town's equipment was single-purpose, separate trucks were necessary to spread salt and to plow afterwards.

Initiatives Introduced

The following discusses the various initiatives undertaken by the Town over the two winter seasons - 1996-97 and 1997-98.

1. Training
   At the request of the Town Council, management began to adjust their winter maintenance approach. The first initiative was to provide specific training to the equipment operators - not only to increase their understanding of best practices and salt chemistry, but to also obtain buy-in for the need for change. In addition, all winter maintenance staff was trained in best salt management practices. Management recognized that the staff had confidence in their previous methods and that detailed instructions and a good rationale for the changes would be required to gain acceptance of the new approaches. The results of the training were not immediately apparent; however, gradually the operators began to accept the new approaches. Their increased commitment to the new approaches soon became evident in reduced salt use.
   
   
2. Public Information Campaign
   The public originally had an expectation that the town roads would be treated until bare. To address this perception, winter maintenance staff introduced a public information campaign to increase awareness of the costs and environmental effects of excessive salt use, and to demonstrate that public safety could still be maintained with a reduced standard of treatment on Town roads. The public's acceptance of this reduced standard is attributable to the community's high level of environmental sensitivity.
   
   
3. Identification of Priority Areas
   Staff recognized that not all roads provide the same function in the community. Some areas need to be treated to a bare pavement standard because they pose a greater risk or have greater use. The Town began to treat only hills, curves, intersections and roads with higher traffic volumes (e.g., those adjacent to schools and churches) to this standard.
   
   
4. Equipment Improvements
   To improve the efficiency of operations, staff added an underbody plow to their spreader. This allowed operators to plow snow and spread materials at the same time, giving the operators the ability to apply the most suitable method of treatment to the existing road conditions. This change in equipment also improved plowing operations by ensuring that salt was not applied to heavy snow, or plowed off the road too soon after being applied.

Truck with underbody plow and pre-wetting unit.

Calcium Chloride Storage Tank.

In addition, to improve the effectiveness of the salt used, the Town outfitted its spreader with an on-board pre-wetting kit and began applying 25 litres of liquid calcium chloride to each tonne of salt. The modification for pre-wetting involved installing saddle type tanks on the truck with a pump and a feeder line to the spinner. Staff installed a 5,000-litre storage tank to hold the liquid calcium chloride at the maintenance yard.

Costs

The following outlines the incremental cost to implement the changes in salt management practices at the Town over two winter seasons, beginning in 1996-97.

Training

The total estimated cost for training was $5,000 to train five operators. This training occurred in the first year of the program.

Underbody Plow

An underbody plow was added to the main spreader at a total cost of $15,000.

Pre-wetting Equipment

The Town installed a 5,000-litre storage tank for liquid calcium chloride with a transfer pump and put a pre-wetting kit onto their salt spreader. The total cost for this equipment was $20,000.

Calcium Chloride Costs

The Town uses 25 litres of calcium chloride per tonne of salt. If we assume that all salt was pre-wetted at this rate over the 4 seasons, then approximately 50,000 litres were used at a cost of $13,700.

Benefits

The following outlines the estimated incremental benefits of introducing best salt management practices at the Town of Otterburn Park.

Salt Reduction

During the 4-year period from 1996 to 2000, the Town saved approximately 2,400 tonnes of salt over what they would have used if they continued to apply at the 1995 rate. At an average cost of $63 per tonne of salt (delivered), the savings are $151,200. In the two seasons (1996 - 97 and 1997 - 98) the salt savings were 875 tonnes over the 1995 rate, or $55,125.

Environmental Benefits

The chloride reduction associated with a 2,400 tonne salt reduction is 1,456 tonnes¹ . This will reduce the incremental environmental impacts and corrosion.

¹ A kilogram of road salt (NaCl) produces a chloride (Cl-) load of 0.6066 kilograms.

Cost/Benefit Assessment

The following table summarizes the costs and benefits over the four winter seasons, beginning in 1996-97 and ending in 1999 - 00². The benefit to cost ratio is approximately 2.8 : 1 over this period. It should be noted that the benefits listed below are understated because they do not include any environmental benefits or benefits from reduced corrosion. Moreover, the investment in the underbody plow and pre-wetting equipment may generate benefits beyond 1999-2000, which are not captured here.

² The costs and benefits provided are cumulative for the period 1996 to 2000. No adjustments have been made for inflation within this period.

Conclusions

The Town of Otterburn Park undertook a salt reduction program during the later half of the 1990's. With modest investments in equipment and training, the Town was able to achieve a 73% reduction in salt use between 1995 and 2000, despite a 66% increase in the length of road serviced.

The improvements introduced by staff have been received positively and winter operations personnel from other municipalities visit the Town to learn about the salt reduction strategies introduced by Otterburn Park. This has increased buy-in by the Town's operators, who are proud to showcase their accomplishments. This change in organizational culture will make the introduction of future innovations easier.

For Further Information:

Contact:
Mr. Alain Gilbert
Manager
Ville d'Otterburn Park
Voice: (450) 536-0299
Fax: (450) 467-8260
Email: alaingilbert@ville.otterburnpark.qc.ca

Websites: http://ville.otterburnpark.qc.ca/

Other Resources: TAC Syntheses of Salt Best Management Practices

Case Study Author: McCormick Rankin Corporation / Ecoplans Limited

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