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Chloride management is a challenging issue in Minnesota and requires a balance between public safety and the environment. In addition to the balance, chloride management is complex since every winter event is different. The different events can be a result of the type of precipitation, temperature, longevity of the event, timing of the event, etc. In addition to variations in each event, winter seasons can be highly variable from year to year.
Snow and ice maintenance practices vary between road authorities and private applicators. Training, equipment, available resources, client expectations, and political pressure all factor into the amount of deicer being applied.
There is no single BMP that can cost-effectively remove snow and ice and maintain an appropriate level of service for all of the various situations. Chloride management can only be achieved through implementation of an array of different BMPs. The BMPs vary by effectiveness in reducing chloride application and cost of implementing the BMP.
The CMP includes an arsenal of BMPs, which give chloride applicators multiple ways to reduce chloride. This provides BMPs that can be used by high-use/high-experience entities all the way down to low-use/low-experience entities. A wide range of BMPs also allows greater flexibility in the timing and extent of implementation of BMPs.
Traditional BMP strategies can be implemented by chloride applicators. The primary recommended strategies include, but are not limited to:
These strategies are centered on the continued use of chloride containing products in the most efficient and effective manner possible. This approach assumes maintaining the same level of service. There are several industry shifts that are needed to reduce salt waste. These changes are applicable to all winter maintenance areas in which a high level of service is expected: roads, parking lots, and sidewalks. Implementing the strategies above will lower salt use, but it may not be reduced enough to protect or restore all water resources.
As part of the stakeholder process to develop the CMP, a TechEx was developed and consists of hands-on salt applicators and suppliers. The TechEx was engaged to better understand the state of the practice and the BMPs available to the winter maintenance industry. The TechEx provided valuable information on specific BMPs that are currently being used by various entities and the benefits of implementing these salt reducing BMPs. This team has been instrumental in the development of the WMAt that will assist winter maintenance organizations in developing their own customized salt reduction plan. Their knowledge, experience, and dedication to using smart salting techniques has been utilized to create this first ever comprehensive evaluation of all available chloride BMPs. Utilization of this planning tool will allow the user to track progress over time and show the results of the efforts.
The tool can serve as both a reporting mechanism to understand the current practices and as a planning tool to understand future practices. The planning part of the tool will help the user understand the challenges and costs associated with improved practices. The WMAt provides a more detailed and comprehensive list of the BMPs available to winter maintenance professionals.
While the preferred and most effective approach for developing a chloride reduction plan for individual winter maintenance programs is to utilize the WMAt, here are a few BMPs that have been proven to reduce salt use.
These BMPs may not be practical for all winter maintenance programs and should not be considered the best or only options for salt reducing activities, but rather a list of BMPs that many programs have already begun implementing and are seeing reduced salt use as a result. To determine the activities appropriate for each organization please visit the MPCA’s Stormwater Manual to utilize the WMAt.
The MnDOT is a leader in winter maintenance related research in the state. Research reports and technical summaries on the latest research can be found on the MnDOT Research Services website.
The continued use of chloride containing deicing materials to provide safe winter conditions may not be a sustainable long-term solution. Therefore, considering practices that fall outside the current and common methods for winter maintenance are worth evaluating. When evaluating non-traditional methods, it is important to consider the environmental impacts of the methods.
Non-traditional approaches require public acceptance in terms of costs, expectations, and changes in behavior. Implementation of these practices will require a combination of messaging to the public which includes discussion of the potentially significant costs to individuals and government. Five of the main areas where change may be considered include:
In this scenario, the public would be given a lower level of service on the roadways, parking lots, and/or sidewalks. Physical removal of snow would likely remain the same but the salting would diminish. There are many ways in which winter maintenance professionals could change their level of service. For example, roads could be salted less frequently or perhaps less of the road could be salted. Instead of roads free of ice and snow from shoulder to shoulder, the melted zone could be reduced, perhaps to the middle of the drive lane. Salting could be restricted to critical areas such as intersections, ramps, hills, and high speed roads. Road salt would still be used, but to a lesser extent.
Winter speed limits – alter the speed limits to match the driving conditions during winter storm events or super cold weather times when black ice is present. The MnDOT currently uses a managed traffic lane approach for dealing with high traffic volumes and congestion on the interstate system within the TCMA. It provides a way for the MnDOT to suggest a speed that will reduce braking and further congestion. This same approach could be utilized to manage the expectations of drivers in terms of speed during snow and ice conditions. The temporary winter speed limit approach has been taken in several states including Illinois, Pennsylvania, Colorado, Maine, and Oregon.
In this scenario, government transportation agencies and private industry would adopt different forms of pavement that can be kept clear with less or without the use of salt. This could include various forms of heated roadways, new types of improved traction surfaces, surfaces constructed with internal anti-icing features, solar roadways which could generate heat as well as electricity, permeable pavements, and flexible pavements. Narrower roadways may also allow for less application of deicing material.
Urban design methods such as parking ramps and covered parking, skyways or covered walkways, porous paving, public transit, transit-oriented development, and higher density development may also help to reduce impervious surfaces, reduce impervious surfaces requiring deicing, and reduce the overall chloride use.
Use of winter tires or other types of tires with improved traction could be required. This might possibly reduce the expectations for a high level of service, and any salt savings would need to be linked to this secondary step of diminished road melting. There remain concerns that driver behavior would not change enough to allow less salt use. Some types of tires have been associated with increased road wear and subsequent pollution, and Minn. Stat. 169.72, prohibits studded tires. The challenge with this approach lies again with public acceptance and driver education on how to safely use winter tires. There would also be a direct cost to consumers and the enforcement of such a requirement. Increased maintenance to roads would likely be an indirect cost associated with this approach, which the resulting salt savings would be modest at best.
Work with large employers to establish a work from home policy during snow events for employees who have suitable jobs. Possibly this will reduce traffic enough during critical times to allow maintenance to be more effective with less salt.
There is a fairly wide variety of other chemicals that can be used for anti-icing and/or deicing, chemicals which do not contain chloride. However, there are significant environmental concerns with most of the existing alterative products. In general the toxicity of non-chloride based deicers is often more severe to surface water organisms in the short term as the chemicals breakdown. There are fewer long-term concerns with non-chloride deicers, which should be evaluated against the long-term permanency with chloride. Of the four strategies, this may be the easiest to implement, but the environmental impacts of these alternatives are the highest of the options listed and needs to be better understood.
See MnDOT’s Transportation Research Synthesis Report: Chloride Free Snow and Ice Control Material for further information on non-chloride deicers and other non-traditional strategies such as permeable pavement, reducing road widths, solar, and others.
Snow melting equipment may be a viable solution in some cases. However, the costs, practicalities, and other environmental consequences of snow melting equipment should be explored further before implementing this method.
More training and professional development opportunities can be found in Appendix D. MS4 Permit Implications/Strategies/Reporting
One of the challenges for public road authorities is the variability in road types, conditions, and meeting driver expectations. Each municipality is faced with unique challenges and circumstances that will play a role in determining the specific BMPs implemented. Development of winter maintenance policies/plans that are proactive and aim to minimize salt use is a critical first step for all winter maintenance programs to begin implementing the BMPs in an effective and strategic way. Training and regular professional development for all applicators is another key strategy to allow winter maintenance programs to reduce overall chloride use while providing an appropriate level of service.
Municipalities in the TCMA make up the most significant portion of salt applicators and would be expected to take on the majority of the BMP activities for reducing chloride. Those municipalities with a National Pollutant Discharge Elimination System (NPDES) Permit with the MPCA in a chloride impaired watershed will be required to report progress on the implementation of the salt reducing BMPs beginning after issuance of the next Phase 2 MS4 permit, which is expected to occur in 2019. The Phase 1 MS4s, (St. Paul and Minneapolis) will be asked to report their progress in 2016.
The WMAt is a valuable resource to MS4s in terms of prioritizing and implementing the BMPs. Use of the WMAt is not a requirement but will allow each MS4 to determine their own priorities that may be based on cost, location, ease of acceptance, or other important factors unique to the MS4’s particular situation. The WMAt provides the specific BMPs related to all areas of winter maintenance to aid in the development in a detailed plan that meets the unique conditions of each individual program and can be prioritized and implemented according specific needs and constraints.
Another valuable resource for public road authorities is their peer group. Several public road authorities have improved practices, significantly reduced chloride use, and have recognized cost savings by implementing BMPs. These success stories, when shared between entities can be a great way to demonstrate specifically how chloride reductions have been successfully achieved. Case studies describing some of these local success stories and specific areas of improvement are discussed below in Section 3.5.
The MS4 reporting will consist of discussion of the BMPs that have already been implemented and the BMPs that are planned, including a timeline for implementation. Further information on reporting requirements can be found on the MPCA MS4 program website.
A major challenge in the overall reduction of chloride use in the TCMA is getting private applicators to reduce chloride usage. There are five primary hurdles related to this effort:
Two potential approaches to educating/training private applicators include a required training approach and a voluntary training approach, both discussed further below. A required training assumes that an ordinance or other regulatory mechanism is adopted by a governing body that requires training. A voluntary approach assumes that there is no ordinance or regulatory mechanism in place.
Potential Required Training Approach: for watersheds with chloride impairments (or suggested reductions)
Voluntary Training Approach:
The winter maintenance industry has changed since the MPCA Smart Salting training program started in 2006. The training itself has also changed. By making the training valid for a fixed number of years, this will encourage on-going awareness of the winter maintenance BMPs, keep the industry current with regulations, and strengthen communication between maintenance organizations and strengthen communication between the environment and maintenance. For optimal success these considerations should be made:
In addition to education, legislation that limits liability for private applicators that are certified under the Smart Salting training program would enable them to use less deicer without fear of litigation. An important aspect to a statute like this is requiring training in order to maintain an appropriate level of service. The State of New Hampshire passed a new law, RSA 489-C effective November 1, 2013, which limits the liability of business owners who contract for snowplowing and deicing as long as the applicator is certified through the New Hampshire Green SnowPro Program. The entire law can be found at: www.gencourt.state.nh.us/rsa/html/NHTOC/NHTOC-L-489-C.htm.
Feedback from stakeholders in Minnesota has indicated that many of the private applicators over-apply salt because of concerns about litigation. A law similar to New Hampshire’s RSA 489-C could change salt application behaviors of private applicators by limiting their liability.
In some cases, compensation for winter maintenance is based on the amount of salt used, which can incentivize over-application of salt. In this case, a boilerplate should be developed and performance based contract for private entities to use when contracting for winter maintenance services. Performance based contracting methods and the boilerplate contract could be part of the education and training programs for private applicators.
A clear message on why reducing chloride is important for the environment, important for saving money, and how to effectively apply chloride will be the key to changing salt application behaviors by homeowners and small businesses. This messaging should be carried out by various state and local governmental entities in order to reach a broad range of people in the TCMA.
Nine Mile Creek approached this by providing a measuring cup type salt scooper to homeowners and small businesses in order to raise awareness of the amount of salt they are using. Homeowners currently not using salt should be encouraged to continue without salt. See detailed survey results in Appendix C and Section 3.4 for additional information on public education.