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Pages 100-110

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From page 100...
... 100 This chapter shows the state DOT how to determine the efficiency and effectiveness of innovative compliance solutions. It provides state DOT practitioners with an overview of how watershed-based strategies can be used to achieve compliance with TMDL requirements.
From page 101...
... Effectiveness of Innovative Solutions 101 which is described later in this chapter, can help state DOT practitioners evaluate and compare watershed-based compliance strategies for a given project, as well as for broader application to mitigate effects of multiple projects and of the highway network. Limitations The ability to institute watershed-based approaches depends on the flexibility of existing legal frameworks.
From page 102...
... 102 Approaches for Determining and Complying with TMDL Requirements Related to Roadway Stormwater Runoff In addition to regulatory limitations, the framework for watershed-based approaches can be difficult to establish and maintain. If a credit system is not already established within a state DOT's jurisdiction, implementation of watershed-based approaches may be limited by cost, including funding positions to develop, institute, approve, and keep accurate accounts of credits.
From page 103...
... Effectiveness of Innovative Solutions 103 Pollutant Source Control and Traditional BMPs Off-Site Mitigation or Credit Trading TSS Advantages • Removal is well understood and achievable. TSS can often be controlled using inexpensive source control measures.
From page 104...
... 104 Approaches for Determining and Complying with TMDL Requirements Related to Roadway Stormwater Runoff Major Elements of a Trading Program A crediting program must define baseline conditions, baseline requirements, trading ratios, methods for the calculation of credits, and methods for credit accounting and tracking (Samanns et al.
From page 105...
... Effectiveness of Innovative Solutions 105 Tar-Pamlico, Neuse River, Jordan Lake, and Falls Lake watersheds. A developer must either implement the on-site BMPs or join in a regional stormwater strategy before the offset nutrient options become available for buying or selling.
From page 106...
... 106 Approaches for Determining and Complying with TMDL Requirements Related to Roadway Stormwater Runoff major metropolitan areas, including the Bay Area (trash and mercury) , Los Angeles watershed programs, and the San Diego Water Quality Improvement Plans.
From page 107...
... Effectiveness of Innovative Solutions 107 • Cherry Creek Reservoir Drainage Basin Priority Trigger: Any portion of a project discharging to the Cherry Creek Reservoir Drainage Basin is a Priority Project. Nutrient Bank/Nutrient Credit Registry Nutrient banking is an alternative compliance program whereby designated nutrient credits are produced in watersheds or trading areas that result in a surplus of load credits after baseline conditions are met.
From page 108...
... 108 Approaches for Determining and Complying with TMDL Requirements Related to Roadway Stormwater Runoff FHWA Feasibility Study The FHWA Feasibility Study for the Development of a Frame work for an Effective Stormwater Quality Credit/Banking/Trading System provides state DOT-oriented guidance on how to implement a water quality crediting program (Samanns et al.
From page 109...
... Effectiveness of Innovative Solutions 109 load reduction (%TLR) targets for volume, TSS, and TN, but are unable to meet the TP %TLR target.
From page 110...
... 110 Approaches for Determining and Complying with TMDL Requirements Related to Roadway Stormwater Runoff While the WBSMT provides a proof-of-concept for comparing and evaluating on-site versus off-site and in-kind versus out-of-kind approaches for addressing TMDL WLAs, the type and extent of out-of-kind practices depend on the factors of safety and mitigation ratios that are accepted by the regulatory authorities when considering equivalency of approaches and uncertainty of the methods and data. In the example output shown in Figure 28, which uses default values in the WBSMT tool, a relatively small amount of stream improvement could potentially meet the outstanding phosphorus %TLR.

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