1 / 30

Research Objectives

NCHRP 25-53 Approaches for Determining and Complying with TMDL Requirements Related to Roadway Stormwater Runoff. Research Objectives. Provide foundation of approaches for DOT compliance with TMDLs by addressing the following objectives:

conan
Télécharger la présentation

Research Objectives

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. NCHRP 25-53Approaches for Determining and Complying with TMDL Requirements Related to Roadway Stormwater Runoff

  2. Research Objectives Provide foundation of approaches for DOT compliance with TMDLs by addressing the following objectives: • Analyze data, statistics, and information about stormwater runoff from roadways • Identify strategies for determining the significance and from roadways • Identify practical feasibility of implementing traditional structural and nonstructural BMPs • Identify approaches for determining the relationship between performance and cost effectiveness. • Identify approaches for determining the efficiency and effectiveness of innovative solutions not commonly used by state DOTs Impaired Waters (303(d) listed)

  3. Contents of 25-53 Chapters • CHAPTER 1 Introduction and Project Overview • CHAPTER 2 DOT TMDL Negotiation and Engagement • CHAPTER 3 Significance of Stormwater Pollutants • CHAPTER 4 Compliance Strategies Approach • CHAPTER 5 Prioritizing Watersheds and BMPs • CHAPTER 6 BMP Pollutant Removal Performance • CHAPTER 7 BMP Cost and Effectiveness Analysis • CHAPTER 8 Effectiveness of Innovative Solutions • CHAPTER 9 Comparing On-Site and Off-Site Approaches • CONCLUSION • REFERENCES • ABBREVIATIONS AND ACRONYMS • APPENDIX A DOTs Included in TMDLs • APPENDIX B Sample Unit Area Load Results from SELDM Model • APPENDIX C Reach Prioritization Example

  4. Overview of Content • DOT Negotiation and Engagement • Pollutants of Concern and Source Analysis • Atmospheric Deposition • Background Sources • Varying Sources by Land Uses • Compliance Strategies • Structural vs. Non-Structural BMPs • TMDL Alternative Compliance • Pollutant Banking/Trading/Crediting • Watershed Stakeholder Collaboration • DOT Watershed Significance • BMP Performance and Feasibility • Cost Analysis and Effectiveness • Innovative Solutions

  5. TMDL Negotiation and Engagement • Does DOT have drainage area in watershed/TMDL? • Yes: identify primary POC and participate to develop TMDL/WLAs • No: track status and comply with DOT permit • Is POC a primary pollutant for a DOT? • Yes: participate to develop TMDL/WLAs • No: track status and comply with DOT permit (provide data results if named in TMDL) • On-site and Off-site compliance alternatives • Pollutant Based Strategies • Watershed Management (Banking/Crediting System) • Municipality collaboration • Typically when DOTs are <1% of watershed • Recommend collaborative compliance Pollutant-Based Compliance Strategies

  6. Significance of Stormwater Pollutants How to identify POCs for DOT TMDLs? Two quantification queries using US EPA ATTAINS Database: • TMDLs with Transportation Agencies Listed (Current TMDLs) • Urban Runoff Impaired Waterbodies (Possible Future TMDLs) Results: • 20% of developed TMDLs list state agencies • 21 primary pollutants of concern within 6 pollutant categories targeted for analysis • Growing number of TMDLs and decreasing number of 303(d) listings nationally TMDL pollutant categories and pollutants targeted for analysis Comparison of approved TMDLs to new impaired waterbody listings over time

  7. Significance of Stormwater Pollutants (cont.) • Factors that contribute to the relative contribution of roadways on downstream water quality? • Highway Maintenance (Salt/Sanding) • Run-on • Atmospheric Fallout • Vehicle Deposition • Project Objectives: • Create analysis protocols that allow DOT practitioners to investigate these factors for local conditions. Conceptual roadway pollutant load mass balance, adapted from Harned (1988)

  8. Significance of Stormwater Pollutants (cont.) • Background Soil Concentrations • Background soil concentrations for phosphorus and metals based on USGS North American Soil Geochemical Landscape Projects. • Soil percentiles associated with corresponding runoff concentrations. • Majority of sediment in stormwater runoff is from the top 5 cm of soil profile. • Allows practitioners to assess impact of local soil concentrations on observed runoff concentrations. Phosphorus Roadway Runoff Attributed to Soil Wash-off Phosphorus concentrations from top 5 cm. Assumes 70 mg/L TSS roadway runoff concentration. Phosphorus soil concentrations in top 5 cm Smith et al. (2014)

  9. Significance of Stormwater Pollutants (cont.) • Atmospheric Deposition • Spatial heat maps showing proportion of highway runoff concentrations potentially attributed to atmospheric deposition. • Results: • Ammonia and Nitrate: Potentially significant contributors • Chloride: Minor except in areas of salt spray • Mercury and Sulfate: Data limitations, may be significant in certain areas Ammonium Chloride Proportion of 25th percentile concentration attributed to atmospheric deposition

  10. Significance of Stormwater Pollutants (cont.) • Land Use Runoff Concentrations • Developed database of land use runoff concentrations from all known runoff databases. • Reported runoff concentration summary statistics for each POC. • Allows practitioners to compare roadway concentrations to adjacent land uses. Databases Mined: • Highway runoff database (HRDB) • National Stormwater Quality Database (NSQD) • International Best Management Practice Database (BMPDB) • Agricultural BMP Database (AgBMPDB) Land Uses Cataloged: • Highways (by traffic volume) • Commercial • Industrial • Institutional • Residential • Open Space • Agricultural

  11. Significance of Stormwater Pollutants (cont.) • Land Use Load Comparison Protocol • Compare roadway loading rates to adjacent land uses to determine anticipated contribution. • Protocol for use of Stochastic Empirical Loading and Dilution Model (SELDM) to compare loading rates. • Inputs: • Land Use Runoff Concentrations: Statistics are defined for user input into SELDM • Imperviousness: Defined by land use • Precipitation: Defined based on study location • Analyzed Constituents: Defined based on runoff concentration and distribution statistics Annual unit area loading rate exceedance for Pacific Northwest

  12. DOT Alternatives for TMDLs with Challenging Compliance Requirements • Early Engagement with state agencies (US EPA/State Regulator) • DOTs should get involved throughout 303(d) listing and TMDL development phase • Use the targeted pollutants list (POC for DOTs) • Determine DOT drainage areas in watershed/TMDL • Validate accuracy of TMDL WLAs (adjust, if necessary) • Implement Feasibility Study • For removal from TMDL (provide data results) • Waterbody specific compliance measures (source control, etc.) • Reopen and Renegotiate a TMDL with State Regulator/US EPA

  13. TMDL Compliance Strategies Compliance Strategy Identification Process

  14. TMDL Compliance Strategies (cont.) • Treatment options for a specific POC • On-Site Planning Track • Identify Applicable unit treatment processes (UTPs) based on source, form and chemical speciation. • Structural and Source Control BMPs • Off-Site Planning Track • Watershed-based compliance strategies (Banking/Crediting/Trading Credits, Restoration/Preservation). • Identify a metric equivalence for any cooperative efforts to quantify loads reduced. • Structural and Source Control BMPs Treatment processes by POC

  15. TMDL Compliance Strategies (cont.) • Pollutant Category Compliance Strategies • Compliance strategies focus on Sediment, Nutrients, Metals, Bacteria, and Chloride categories. • DOTs can use appropriate strategies and considerations based on pollutant characteristics. • Compliance approaches include institutional controls, structural retrofits, or watershed stakeholder collaborative activities (e.g., wetland restoration). • Compliance strategies identify the feasibility, critical considerations and critical constraints for each pollutant category.

  16. TMDL Compliance Strategies (cont.) • Sediment Compliance Strategy • Sources: deposition, washoff of adjacent soils, vehicular traffic and urban activities

  17. TMDL Compliance Strategies (cont.) • Nutrients Compliance Strategy • Sources: Soils, vegetation and agricultural practices

  18. TMDL Compliance Strategies (cont.) • Metals Compliance Strategy • Sources: Vehicular traffic, litter, spills, and roadway maintenance operations

  19. TMDL Compliance Strategies (cont.) • Chloride Compliance Strategy • Sources: Deicing chemicals and atmospheric deposition (coastal areas)

  20. Treatment BMPs (Stormwater Devices) Permeable Friction Course Source: Google Detention basins or Infiltration basins Bioretention Media Filter – Earthen Biofilter Strip/Infiltration Trench

  21. Evaluating Watersheds and BMPs • Overall BMP Selection Framework • Prioritize Implementing Locations • Assess Feasibility of Site Conditions • Prioritize BMP Selection • Multi-Benefit Criteria • BMP Performance • Maintenance and Safety Access • Space and Geometry Requirements • Aesthetics • Social and Ecological Benefit • Climate Adaptability • Groundwater Constraints • Soil Impacts Prioritization and feasibility framework process

  22. BMP Performance • Performance Evaluation Methodology Overview • Identify Evaluation Metrics • Determine Scale of Comparison • Select Evaluation Approach and Pollutant Removal Algorithm • Size BMP based on locally prescribed methods • Determine BMP capture efficiency • Segregate captured runoff into retention and treatment flow paths • Assign performance metrics to bypass, retention, and treatment flow paths • Compare performance • Conduct Comparative BMP Performance Assessment • Sources of BMP Performance Data (IBMPD) & Evaluations • POC based performance evaluation references BMP performance comparison methodology flowchart Conceptual model for calculation of load reduction based on flow pathways (Taylor et al., 2014)

  23. BMP Performance (cont.) • Available Tools for BMP Performance Evaluation • Structural BMPs • International Stormwater BMP Database • EPA SWMM • EPA Stormwater Calculator • SELDM • NCHRP 792: Long-Term Performance and Life-Cycle Costs of Stormwater Best Management Practices Tools • Non-Structural BMPs • Limited data sources • Highly site-specific BMP performances • No data repositories or quantitative performance planning tools • Technical studies with performance data Comparison of BMP performance evaluation tools

  24. BMP Cost and Effectiveness Analysis • NCHRP developed BMP Evaluation Tools • Long-Term Performance and Life-Cycle Costs of Stormwater Best Management Practices • Bridge Stormwater Runoff Analysis and Treatment Options • Quantity of BMPs • Feasibility study of outfalls in TMDL watersheds to identify potential BMP locations or evaluate every outfall as a potential BMP location • Use these quantities as a guide in determining the total TMDL compliance cost • Rough $$ per implemented BMP • Incremental costs for increasing BMP footprint • Cost effectiveness through off-site Compliance strategies • Collaborative Implementation • Pollutant Offset/Crediting Area-Weighted BMP Costs (after Weinstein et al. 2017)

  25. Effectiveness of Innovative Solutions • Watershed approaches for DOT TMDL Compliance • Feasible Watershed-based Approaches • Pollutant Banking, Pollutant-trading, Off-site Mitigation, Off-site Source Control • Traction Deicing Applications • Restoration/Preservation • Brake Pad Partnerships • Watershed Management/Cooperative implementation • Limitations for Watershed-based Approaches • Framework and agency receptiveness to watershed-based approaches • Feasibility of TMDL crediting approach for pollutant of concern • Funding Constraints (Right of way vs. off-site) • Context and limitations for applying watershed-based approaches to TMDL compliance • Approaches for defining offset ratio for specific pollutant • Effective Collaborative Implementation Programs • Chesapeake Bay TMDL Watershed Implementation Plans (WIPs) • Los Angeles Region Enhanced Watershed Management Plans (EWMPs) • Great Lakes Restoration Initiatives (GLRI) • Lake Elsinore/Canyon Lake Nutrients TMDL (Task Force)

  26. Effectiveness of Innovative Solutions • Successful Watershed-based Approaches • North Carolina – Nutrient Offset & In-Lieu Fee Program • First implement on-site treatment controls to meet nutrient compliance • If unable to do so, pay in to the program to off-set the nutrient load reductions • Caltrans Stormwater Compliance Program • 20-year Program • Achieve 1,650 Compliance Units (CUs) or acres of treatment within right-of-way annually • Collaborative projects achieve 1 CU per $88,000 funded on project • Colorado – New Development and Redevelopment Permanent Water Quality Mitigation Fund • Priority projects (303(d) listed, Impervious area increase of 20% or more, or project within cherry creek reservoir)

  27. Comparing On-Site and Off-Site Approaches Comparative analysis of on-site vs. off-site water quality treatment Key Resources • FHWA Feasibility Report on Crediting (Louis Berger Group et al., 2015) • Watershed Based Stormwater Mitigation Toolbox (Weinstein et al., 2016) Key Factors • Treatment Location Prioritization • Cost Benefit Analysis • Partnership Goals

  28. Overall Results Key Guidelines for DOT Practitioner Collection and characterization of monitoring data of highway runoff Get Involved Early! • Involvement and participate in TMDL development with State Regulators • Remove DOT as a stakeholder due to negligible or no impacts • Renegotiate a TMDL with inaccurate/incorrect DOT allocations Consider implementing recommended alternative strategies • Cost Effective, Innovative and Actively Implemented Nationally. TMDL Compliance tracking and data management

  29. Research team • Michael Baker International • Anna Lantin • Laura Larsen • Ankita Vyas • Michael Barrett • Geosyntec Consultants • Marc Leisenring • Kevin Koryto • Ariel Mosbrucker • LDP Consultants • Linda Pechacek

  30. THANK YOU • Questions?

More Related