TCMA Chloride TMDL - Implementation Strategy Summary

Implementation Strategy Summary

Implementation strategies to restore the TCMA waters impaired by chloride are presented in Figure 10 below and discussed further in this section. Additional information is included in Section 3 of the TCMA CMP. While these strategies apply generally across the TCMA, individual entities, such as the WDs or cities, may want to develop individual plans for specific impaired and high risk waters. Prioritizing reduction activities is a local decision and requires evaluation of local conditions and variables. Section 3.1 of the CMP offers some suggestions.

Implementation Strategy to meet the TCMA Chloride TMDLs

Performance-Based Approach for Achieving TMDLs

Deicing salt is the most common and the preferred method for meeting the public’s winter travel expectations. There is currently no environmentally safe and cost-effective alternative that is effective at melting ice. Therefore, continued use of salt as the predominant deicing agent for public safety in the TCMA can be expected. Setting a specific chloride load reduction target for each individual winter maintenance chloride source is challenging, as is measuring actual chloride loads entering our surface and groundwater from salt and other nonpoint sources in the TCMA. Therefore, priority should be put on improving winter maintenance practices to use only a minimal amount of salt, also referred to as smart salting, across the entire TCMA. With these considerations in mind, the implementation approach for achieving the TMDLs and protecting all waters in the TCMA is to focus on performance of improved winter maintenance practices as well as continuing to monitor trends in local waterbodies. A standard approach to the TMDL implementation is to translate the WLA component of the TMDL directly to a numeric permit limit, which is typical for permitted facilities with monitoring requirements. In the case of urban stormwater regulated through a MS4 Permit, the WLA may be presented in the form of a percent reduction from a baseline condition. The specified percent reduction is then included in the MS4 Permit. With a performance-based approach, the numeric WLA is translated to a performance criterion. This can include the development and implementation of a winter maintenance plan which identifies a desired level of BMP implementation and a schedule for achieving specific implementation activities. Progress made towards those goals are documented and reported, along with annual estimates of salt usage and reductions achieved through the BMPs implemented.

In cases where it is not “feasible” to calculate a numeric effluent limit, federal regulations allow for the use of BMPs as effluent limits (40 CFR § 122.44(k)). Such a performance-based or BMP approach to compliance with the WLAs is being taken by states to address the Chesapeake Bay TMDL for nutrients. The TMDL is being implemented through state Implementation Plans. Some states are taking a performance-based approach to addressing urban stormwater sources, requiring minimum levels of BMP implementation rather than requiring specific levels of pollutant load reductions.

A performance-based approach will be tracked through documentation of existing winter maintenance practices, goals for implementing improved practices including schedules, and reporting on progress made. Entities may choose to use the WMAt, which is a smart salting BMP tracking tool, to assess and document practices and set goals, or another approach of their choice. More information about the WMAt can be found in Appendix B of the TCMA Chloride Management Plan. Entities should track progress and document efforts, including, to the extent possible, estimates of reduced salt usage as a result of improved practices. Entities that have achieved their goals for winter maintenance will have documented their practices in a winter maintenance plan. This plan should be reviewed annually and evaluated against the latest knowledge and technologies available for winter maintenance.

The performance-based approach does not focus on specific numbers to meet, but rather on making progress with BMPs. Progress is measured by degree of implementation and trends in ambient monitoring. In a traditional approach with numeric targets, progress would be measured by accounting for salt applied and comparing to the targets. The performance-based approach is intended to allow for flexibility in implementation and recognize the complexities involved with winter maintenance. Because the performance-based approach doesn’t provide a specific numeric target, a limitation of the approach is that it is not definitive on when enough progress has been made. This can only be determined by continued ambient monitoring that demonstrates compliance with water quality standards.

MS4 and Roads=

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, 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 across the TCMA. 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 in which to reduce chloride. This provides the 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 the BMPs.

Traditional BMP strategies can be implemented by chloride applicators. The primary recommended strategies include, but are not limited to:

1. Shift from granular to more liquid products and higher liquid to solid ratio blends
2. Improved physical snow and ice removal
3. Snow and ice pavement bond prevention
4. Training for maintenance professionals
5. Education for the public and elected officials

This strategy consists of the continued use of chloride containing products in the most efficient and effective manner possible. This approach assumes we maintain 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.

Winter Maintenance Assessment tool

A tool called the WMAt has been developed by the MPCA and is available for use by all winter maintenance professionals. The WMAt is a voluntary tool that can be used to understand current practices, identify areas of improvement, and track progress.While optional, everyone that is involved in winter maintenance is highly encouraged to use the WMAt. The tool is intended to streamline and simplify implementation goals and strategies. The tool can also be a great way to compare practices with other entities and learn from each other in order to achieve the greatest chloride reductions while providing a high level of service. Utilization of this planning tool will allow the user to track their progress over time and show the results of their 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 side of the tool will help understand the challenges and costs associated with improved practices.

The WMAt provides a more detailed and comprehensive evaluation of all the BMPs available to winter maintenance professionals. More details about the WMAt can be found in Appendix B of the TCMA CMP.

Examples of salt saving BMPs for winter maintenance programs

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.

1. Calibrate all equipment regularly (both liquid and granular systems)
2. Integrate liquids (avoid applying dry material)
3. Develop a Winter Maintenance Policy/Plan and share it with supervisors, crew and customers
4. Provide state of the art winter maintenance training, education, and professional development for all who work in the industry
5. Store salt indoors and on an impermeable pad
6. Anti-ice before events to reduce bonding of snow to pavement
7. Use ground speed controllers
8. Upgrade to equipment that can deliver low application rates
9. Select products that will work well given the pavement temperatures and conditions
10. Select application rates based on road temperatures and trends, the product used, cycle time, and other factors
11. Start mechanical removal as soon as possible, and continue throughout the storm
12. Use a variety of methods to reduce bounce and scatter of salt
    1. Reduce speed
    2. Higher liquid to granular ration
    3. Lower spinner elevation
    4. Chutes or skirts
    5. Reduced spinner speed or turn off
    6. Target crown of the road or near the center
13. Refine application rate charts and continually test lower rates

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.