Loading...
9.d1 Dust Control Policy discussion Date: 8-18-20 From: Adam Hawkinson – Director of Public Works To: Scandia Mayor, City Council, City Administrator RE: Dust Control on Community Gravel Roads A dust control policy using Calcium Chloride (CaCl) on the community gravel roads was adopted in 2010 when the City agreed to pay for the applications. The benefits of dust control go beyond controlling the debris in the air. The added benefit of the stabilized surface, due to the chemical keeping the road moist, is that the fines are not lost and the stone and sand sized particles remain intact. When these large sized particles lose the fines that hold them in place, the surface becomes loose, wash boarding occurs, and traction is compromised. Budgeting: The City currently spends about $26,000 per year on dust control for the gravel roads in the community. There is an additional $2,200.00 that is reimbursed by Cedar Cliff. The total budgeted is $28,200 for this reason. This amount is about 20% of the Public Works road maintenance budget. At times there are requests for more applications which brings it just above the 20%. Performance: There are advantages and disadvantages to using a liquid vs granular CaCl for dust control. The advantages of liquid use are that it is widely used so contractors are equipped to apply the product and the calibrating is set the same for most roads since there is an application rate best practice. The disadvantage is that the roads need to be moist at the time of application so that the product will absorb into the surface. The absorption takes time so any traffic on the road will pick up the dust control product on their vehicles; not good because CaCl is very corrosive. Timing - application needs to occur after a rain but not when there is rain in the forecast for the next few days. At this point, two applications are needed for the liquid process. This helps control the dust longer for the community. The advantages of granular use are that it is blended into the road right after application, it can be done during dry conditions, and once it has bonded to the gravel, the corrosive effects on vehicles is very low. From the last two years of trying the granular on the roads the control has been good to very good and there has been only one application during the season. The following year’s application rate can be reduced to 0.5 to 1 pound of flake per square yard for roads treated the previous year. Since it is incorporated into the gravel base, it may be more environmentally friendly, though there are no studies to prove the point. The disadvantage is that the grader blades need to be changed to a scarifier edge which is more labor intensive. Some contractors do not have the proper equipment for this application process. Vehicles can pick up and track the CaCl just as the liquid, until it is incorporated into the gravel. Future Dust Control Calcium Chloride is still the most effective and cost-effective chemical for dust control. It is in the best interest of the City to maintain a dust control program. One proposed change to the policy would be to support the use of a granular application instead of the liquid. The continued use of the granular product would lower the future costs of dust control because of the carry-over effects from the year before. There would be one application per year which would last the entire year depending on weather conditions. Another adjustment the council may want to consider in the dust control policy is cost sharing for those residents who request dust control beyond what the City provides. Changes to the dust control policy could impact the budget for Public Works. PW staff recommends a council decision on any changes to the policy prior to the 2021 budget approval. City of Scandia Dust Control Application Policy Adopted by the City Council February 16, 2010 The City of Scandia considers that applying dust control measures improves the quality of life of its residents living on gravel roads. The application of calcium chloride improves the gravel surface by compacting the gravel, which makes for a smoother surface and thus requires less grading, as well as reducing dust. The City also encourages the application of dust control to private roads and parking lots. Dust Control on Public Roads The City of Scandia will pay for one granular application of dust control chemicals annually to the city’s remaining gravel public streets. The City’s Public Works strive to avoid grading over the “Dust Control Area” after dust control chemicals have been applied. However, safety of the traveling public is of the highest concern, and grading may be necessary as determined by the Maintenance Supervisor. Dust control applications may continue to be effective even after occasional passes by road grading equipment The City does not guarantee the performance of dust control chemicals. The material has historically performed well when the road and weather conditions were favorable. Traffic volume can also affect its performance. Any additional treatment requests will be charged to the property owner. The cost will include equipment, labor, and material. The requested area to be treated will be marked out by the requestor. Special Provisions for 185th Street Because 185th Street serves an active sand and gravel mine, the need for dust control far exceeds what would be necessary due to normal traffic volumes. Consistent with the requirements of Chapter 4 of the Development Code and the Conditional Use Permit and Annual Operators Permit (AOP) for the mine, the City will arrange for dust control applications for this street at its discretion. The operator will pay the full cost of dust control applications for this street. The location and frequency of applications may be modified by provisions of the AOP. Private Roads, Driveways and Parking Lots Business owners, residents of private roads and driveways, and other local governments may also participate in the dust control program by paying the full cost of the calcium chloride applied to the area they designate, plus fifteen percent of the contractor’s cost to cover city staff time and administration of the program. In the spring of each year, city staff will obtain a quote to establish the cost for the current year. City staff will notify such business owners and residents who have requested application in the past of the current cost, and will bill them after the application with the payment due to the city within 30 days.