The management of the Cypress Bowl ski area, near Vancouver, B.C., has been able to cut its winter maintenance costs by 34%, while reducing the amount of chlorides released into the environment by 73%. The key is use of liquid chemicals as an anti-icing agent and as a prewetting agent for sand and road salt.
John Imlah, snow removal and grooming manager for Cypress Bowl, stated that "anti-icing and prewetting has worked so well for us that the other ski areas managed by the same group are adopting the same methods."
Anti-icing is an aggressive approach to winter storm maintenance by an application of a liquid deicer to the roadway surface ahead of the storm. Prewetting is the application of a liquid chemical to a dry solid such as sand or road salt prior to spreading on the roadway.
Cypress Bowl, in cooperation with the Insurance Corporation of British Columbia’s Road Sense safety program, took a large step toward state-of-the-art technology in winter maintenance by moving to aggressive anti-icing and liquid chemical strategies.
A case study produced by Ice & Snow Technologies LLC (IST), Walla Walla, Wash., compared the costs of the previous sand and salt strategy to the recently adopted anti-icing and prewet strategies. The months of March 2000 and March 2001 were chosen for the comparison. They had nearly identical weather, according to the Washington Department of Transportation’s winter index, which allowed for a one-to-one comparison of operational data. These months also were typical for the area, which allowed for some expanded analysis.
Setting the snow scene
Cypress Bowl is a ski area located in a provincial park adjacent to metropolitan Vancouver. The agency maintains the parking lots and spur roads for the facilities as well as the main access road. The treated roadway is roughly 8.9 miles long with an average grade of 5.5% and consists of 29.9 lane miles.
The climate at Cypress Bowl is similar to that of the Oregon and Washington Cascade Mountains, with relatively moderate winter temperatures and, at times, heavy snowfall. At a base elevation of 3,214 ft, the annual average snowfall is 244 in. The snow is generally heavy and relatively wet.
Getting it done
The winter season lasts from Nov. 1 to April 1, and there are up to five supervisory or lead people providing coverage 24 hours a day, seven days a week. The target level of service is a bare, wet pavement.
Pavement temperatures are measured with a ±1?F accuracy using a hand-held infrared radiometer. Measurements are taken as needed based on storm conditions and experience in the area. All data is recorded for future analysis. Knowledge of pavement temperature is necessary to properly apply chemicals. For example, shaded areas are often colder and need chemicals, while sunlit areas are warmer and do not.
The Cypress Bowl maintenance group has two trucks that have spreader hoppers and have been refitted with on-board prewetting equipment. The group also has one liquid application truck and a blade and loader. Originally, all three trucks had spreader hoppers.
Previously, Cypress Bowl’s strategy of choice was a 50:50 mixture of sand and road salt applied after the snow had started to accumulate. The one significant change in their operations was the use of liquid chemicals. In this case, magnesium chloride is used in direct application and as a prewet agent for both sand and salt. Prewetting involves coating the dry solid materials with a small amount of liquid chemical just as it is applied.
The strategy for the application of solid materials has changed very little. Previously, sand and road salt were applied using hopper spreaders. Now they are given a light coat of liquid chemical as they leave the hopper. The prewetting reduces loss of chemicals and sand due to traffic action. Prewetting also accelerates the action of road salt and improves its performance at colder temperatures.
Previously, frost conditions required continuous patrolling with application of sanding material. With new methods and the use of directly applied liquid chemicals (i.e., anti-icing), little or no patrolling is needed, thus reducing labor and equipment charges. In this case the chemicals are applied before the storm, based on weather forecasts and pavement temperatures. In many cases, no sand is needed to assure adequate traction.
Plowing up profits
The use of liquid chemicals, applied either directly or as a prewet for sand and salt, has resulted in a 39% reduction in materials cost and a more efficient operation with less waste.
The 64% reduction in the use of sand is due to the prewetting process. The 80% reduction in the use of salt is partly due to its replacement with magnesium chloride as well as the prewetting process. While Cypress Bowl has no roadway-sweeping program, others who are required to sweep up the sanding material should realize additional savings.
The overall reduction in equipment and labor costs was 28%. This reduction in costs between the two study periods can be attributed to lesser patrol time and reduced equipment use. Liquid chemical use made the reduced equipment use possible.
Liquid chemical use also made possible a reduction in total chloride release. The IST study included an inventory of chloride release. Taking the reduction in salt use and adding in the chlorides from the magnesium chloride, the total release of chlorides into the environment was reduced by 73%. The release for March 2000 was 574,440 lb and for March 2001 was 152,689 lb. Chlorides are known to cause problems with roadside vegetation and water quality, and sanding materials have similar issues. Thus, any reduction in the use of deicer or sanding materials is beneficial to the maintenance budget and the environment.
This year, Cypress Bowl’s mechanics noticed significantly reduced corrosion-related damage to their truck fleet, including the braking systems. The brakes were inspected and showed significantly less rust than in previous years and less scoring from sanding material. The brakes did not need to be replaced this year. The savings in this area are primarily in the cost of parts, because the annual inspection already requires a complete tear-down of the brakes.
In the past, the corrosion-related maintenance for the snow and ice control equipment has been carried out on an annual basis costing approximately $5,070 per year. This work consisted of sandblasting truck hoppers and frames along with loader buckets and frames, followed by spray painting. Grader frames were chipped and painted. Based on inspection of the equipment, Cypress Bowl expects to do this maintenance every three years in the future for an annual cost of approximately $1,690, representing annual savings of $3,380.
In March 2000, there were two crashes reported on the grounds of Cypress Bowl, one of which involved a slippery roadway. In March 2001, there were three crashes reported, none of which was related to a slippery roadway. This is not unusual in that the level of service in both periods was a bare, wet pavement.
The crew reported that there were significantly fewer snow-related crashes during the winter of 2000-01. They also noted the conspicuous absence of the usual number of minor fender benders. Because of the low number of reported crashes, no statistically significant conclusions were possible regarding accident reduction.
The initial capital investment for Cypress Bowl’s anti-icing program was about $41,960, which included the liquid applicator and on-board prewetting retrofits.
The estimated first-year savings were $72,500, which means that the total capital outlay was recovered in the first year, plus a significant bonus. After four years, Cypress Bowl should see a benefit to cost ratio of about 7:1.
The analysis shows that aggressive liquid chemical use has produced a big win for the management of Cypress Bowl as well as for the environment.