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From page 43... ... 43 This chapter shows the state DOT how to develop pollutant-specific compliance strategies. It provides practitioners with a conceptual approach that can be integrated into the TMDL planning process. Read the entire page →
From page 44... ... 44 Approaches for Determining and Complying with TMDL Requirements Related to Roadway Stormwater Runoff Pollutant-based compliance strategies provide a more effective implementation of control measures that are geared toward watershed benefit. Compliance strategies are focused on establishing mitigation measures based on the primary POCs for highway runoff. Read the entire page →
From page 45... ... Compliance Strategies Approach 45 strategies. The pollutant source, partitioning, and speciation impact the selection of a compliance strategy: a. Read the entire page →
From page 46... ... 46 Approaches for Determining and Complying with TMDL Requirements Related to Roadway Stormwater Runoff the watershed. In addition, proximity to receiving waters, magnitude of TMDL exceedance, and cost are important considerations when comparing on-site and off-site mitigation strategies. Read the entire page →
From page 47... ... Compliance Strategies Approach 47 • Erosion Control: Vegetation coverage, slope and outfall protection, and construction BMPs to prevent sediment release from erosion. Refer to erosion and sediment control guidance manuals for specifics on this category (AASHTO Center for Environmental Excellence 2017) Read the entire page →
From page 48... ... 48 Approaches for Determining and Complying with TMDL Requirements Related to Roadway Stormwater Runoff to the pollutant source. Source control considerations for specific POCs are further elaborated on in the discussion of individual pollutant compliance strategies. Read the entire page →
From page 49... ... Fundamental Process Category UTP Operational Components Pollutants Treated/Controlled Coarse Debris Sediment Oil and Grease Nutrients Organics Metals Bacteria Chloride Hydrologic Operations Flow Alteration Peak flow reduction (detention) Xa Xa Volume Reduction Infiltration, evapotranspiration, or reuse (retention) Read the entire page →
From page 50... ... 50 Approaches for Determining and Complying with TMDL Requirements Related to Roadway Stormwater Runoff hyperaccumulators (Salt et al. Read the entire page →
From page 51... ... Compliance Strategies Approach 51 establishing mitigation measures based on primary pollutants of concern for highway runoff. These strategies ensure that the responsibility placed on state DOTs is commensurate with department contributions to the receiving water body impairments and actual watershed loads. Read the entire page →
From page 52... ... 52 Approaches for Determining and Complying with TMDL Requirements Related to Roadway Stormwater Runoff Due to an increase in surface area, smaller sediment fractions carry the majority of other particulate-bound pollutants (Morquecho and Pitt 2005) Read the entire page →
From page 53... ... Compliance Strategies Approach 53 • Maintenance access: To maintain the function of structural practices, sediment removal and practice rehabilitation are required over time. System design should consider available space and how maintenance personnel and equipment can safely access the site, as well as sediment disposal requirements. Read the entire page →
From page 54... ... 54 Approaches for Determining and Complying with TMDL Requirements Related to Roadway Stormwater Runoff gravitational sedimentation. Settleable stormwater solids typically have specific gravities between 1.5 and 3.0 (Li et al. Read the entire page →
From page 55... ... Compliance Strategies Approach 55 Compliance Strategy Method Components Applicability Critical Considerations Critical Constraints Traction Control Plan Source control Reduce sand application rate or switch to alternative material Cold weather climate in which road sanding has been identified as a contributor to sediment loading Identify methodology and consequences of implementing change to traction material application • Public safety • Institutional coordination • Equipment availability • Maintenance • Accessibility • Cost Erosion Control Source control Vegetation or material coverage of exposed soil, channel banks, or outfalls Construction sites or bare areas in state DOT jurisdiction Erodible landscapes or flow paths identified in the watershed Identify applicable erosion control practices and areas for implementation • Longevity • Maintenance • Accessibility • Cost Street Sweeping/ Catch-Basin Cleaning Source control Routine removal of solids from road surface or catch-basin sumps using a Vactor truck or sweeper truck Solids-size fraction of concern has been identified and is removable using prescribed methods Identify anticipated frequency and removal method to achieve pollutant load reduction • Institutional coordination • Equipment availability • Operational costs • Material disposal • Maintenance • Accessibility • Cost Infiltration Volume reduction Basins, vaults, trenches, underground injection controls, or dispersion Applicable to all situations if constraints met Identify available space and moderate to high permeability soils • Soilinfiltration capacity • Groundwater contamination • Space • Clogging • Maintenance • Accessibility • Cost Detention Flow attenuation, separation Detention ponds, wet ponds, or wetlands Solids-size fraction of concern is settleable (≥20 µm) Inclined plate settlers or coagulation– flocculation enhancements for fine solids-size fractions (<20 µm) Read the entire page →
From page 56... ... 56 Approaches for Determining and Complying with TMDL Requirements Related to Roadway Stormwater Runoff remove, requiring sorption or biological mechanisms. The difference in chemical characteristics of dissolved nutrients -- including charge and oxidation state -- has significant implications for selecting compliance strategies (Table 27) Read the entire page →
From page 57... ... Compliance Strategies Approach 57 Source Cause State DOT Controllable Dry Deposition Air currents deposit fine particles on the road surface from nearby sources, such as industrial, agricultural, and exposed vacant land areas. These particles can have particulate nutrients associated with them. Read the entire page →
From page 58... ... 58 Approaches for Determining and Complying with TMDL Requirements Related to Roadway Stormwater Runoff Compliance Strategy Method Components Applicability Critical Considerations Critical Constraints Vegetation Management Source control Removal of leaves and mowing of overgrown vegetation to prevent decay and nutrient release Areas with high concentrations of trees, vegetated medians, or shoulders Identify locations of concern, frequency, and timing of maintenance • Equipment availability • Institutional coordination • Maintenance • Accessibility • Cost Erosion Control Source control Vegetation or material coverage of exposed soil, channel banks, or outfalls Erodible landscapes or flow paths have been identified in the watershed Identify applicable erosion control practices and areas for implementation • Longevity • Plant establishment • Maintenance • Accessibility • Cost Infiltration Volume reduction Basins, vaults, trenches, or dispersion Applicable to all situations if constraints are met Identify available space and soils with moderate to high permeability • Soilinfiltration capacity • Groundwater contamination • Space • Clogging • Geotechnical stability • Maintenance • Accessibility • Cost Detention Flow attenuation, separation Detention ponds, wet ponds, or wetlands Particulate nutrients are associated with settleable solids (>20 µm) Identify available space and determine if settleable fraction is large enough to be useful in reducing nutrient loads • Space • Maintenance • Accessibility • Cost Filtration Filtration/ sorption Bioretention filters, filter amendments Particulate nutrients and possibly dissolved phosphorus or TKN are of concern Identify available space and filter media parameters • Space • Clogging • Maintenance • Accessibility • Cost Multistage Filtration with Anaerobic Zone Microbially mediated transformation Bioretention filters with saturated zone, electron donor material Particular concern for dissolved nitrogen, especially nitrate and nitrite Identify available space, filter media parameters, potential for anoxic zone • Space • Clogging • Maintenance • Accessibility • Cost Vegetated Conveyance Uptake and storage Vegetated swale or filter strip with or without amended soils Dissolved nutrients, areas where plants are not dormant during wet season Identify available space and maintenance plan for vegetation harvesting • Space • Clogging • Maintenance • Accessibility • Cost PFC Pavement Filtration/ sorption PFC-paved roadways TKN, nitrate Identify feasibility of pavement replacement maintenance plan and life span needs. Read the entire page →
From page 59... ... Compliance Strategies Approach 59 runoff. Vegetated columns improved ammonia removal in gravel and sand mesocosms when comparing vegetated to unvegetated columns (Henderson et al. Read the entire page →
From page 60... ... 60 Approaches for Determining and Complying with TMDL Requirements Related to Roadway Stormwater Runoff brake parts, and road surfaces. The fraction-form metals not bound to particulates exist in a dissolved state as free metal ions, as inorganic complexes, or bound to dissolved organic chemicals. Read the entire page →
From page 61... ... Compliance Strategies Approach 61 Treatability. Runoff characterizations have indicated that the concentration of metals in highway runoff is often correlated to TSS. Read the entire page →
From page 62... ... 62 Approaches for Determining and Complying with TMDL Requirements Related to Roadway Stormwater Runoff Compliance Strategy Method Components Applicability Critical Considerations Critical Constraints Street Sweeping/ Catch-Basin Cleaning Source control Routine solids removal from road surface or catchbasin sumps using a Vactor truck TSS are a concern for metals and are removable using prescribed methods. Identify anticipated frequency and removal method to achieve pollutant load reduction. Read the entire page →
From page 63... ... Compliance Strategies Approach 63 waterborne diseases, such as dysentery and cholera, are associated with certain strains of E coli. Read the entire page →
From page 64... ... 64 Approaches for Determining and Complying with TMDL Requirements Related to Roadway Stormwater Runoff feedlots; and uncontrolled manure storage areas in rural or agricultural areas. The point sources tend to have the most profound influence on receiving water bodies during dry conditions. Read the entire page →
From page 65... ... Compliance Strategies Approach 65 strategies identified within Table 35. Therefore, they require similar treatment processes. Read the entire page →
From page 66... ... 66 Approaches for Determining and Complying with TMDL Requirements Related to Roadway Stormwater Runoff natural sources of chloride (such as atmospheric deposition) exist, these contributions tend to be significant only in coastal areas (Granato et al. Read the entire page →
From page 67... ... Compliance Strategies Approach 67 2. Space availability: Some of the best options for dealing with chloride TMDLs may involve evaporation or retention. Read the entire page →
From page 68... ... Compliance Strategy Method Components Applicability Critical Considerations Critical Constraints Traction Control Plan Source control Reduce salt application rate, method, or locations of salt application; use of alternative materials; educational programs for operators Cold weather climate in which road salting has been identified as a contributor to chloride loading Identify methodology and consequences of implementing change to traction chemical application. • Public safety • Institutional coordination • Equipment availability Alternative Paving Materials Source control Construction of alternative road surfaces or roadway heating mechanisms Cold weather climates with access to sufficient power or natural sources of heat; key areas, such as bridges, corners, or locations near affected waterways Identify key locations and economic feasibility. Read the entire page →
From page 69... ... Compliance Strategies Approach 69 agricultural by-products -- such as those from beet juice, molasses, and milk processing -- have also been investigated for use in deicing applications in recent decades (Fay and Shi 2012) Read the entire page →

From page 43...

... 43 This chapter shows the state DOT how to develop pollutant-specific compliance strategies. It provides practitioners with a conceptual approach that can be integrated into the TMDL planning process.