Approaches for Determining and Complying with Total Maximum Daily Load Requirements Related to Stormwater Runoff. Presented by Anna Lantin, P.E.

Transcription

1 Approaches for Determining and Complying with Total Maximum Daily Load Requirements Related to Stormwater Runoff Presented by Anna Lantin, P.E.

2 Presentation Overview / Introduction Impaired Waters Program Background Total Maximum Daily Load (TMDL) Mandates and Municipal Separate Storm Sewer System (MS4) Permits Determination of Significance (Prioritization) TMDL Compliance Strategies Watershed Programs Best Management Practice (BMP) Retrofit what, where, and how for compliance tracking?

3 Impaired Waters Under Clean Water Act Section 303(d)

4 What is 303(d) TMDLs? The "303(d) list" contains impaired and threatened waters (stream/river segments, lakes) that the Clean Water Act requires all states to submit for Environmental Protection Agency (EPA) approval every two years on evennumbered years. The states identify all waters where required pollution controls are not sufficient to attain or maintain applicable water quality standards, and establish priorities for development of Total Maximum Daily Loads (TMDLs). - EPA

5 U.S. Impaired Waters Statistics Source: EPA Website ,000 Impaired Waterbodies 75,000 Causes of Impairments 70,000 TMDLs Approved

6 U.S. Impaired Waters Statistics Source: EPA Website 2017

7 Total Maximum Daily Load What is a TMDL? A plan to achieve Water Quality Standards Maximum amount of pollutant a waterbody can receive and meet water quality standards Mass in kilograms per year or grams per day (kg/year or gm/day) Concentration in milligrams per liter (mg/l)

8 TMDL and Waste Load Allocations TMDL= numeric target x critical flow TMDL = LA Direct Air + LA Open + WLA POTW + WLA Storm Water + Margin of Safety WLA Storm Water = MS4 + General Permits Municipal Phase I MS4 Construction Phase II MS4/Small Industrial Departments of Transportation

9 The Problem Growing number of impaired waters - a challenge for regulators and the regulated community on measurable compliance. Enforceability of TMDLs through MS4 permits vary in requirements across the country Meeting numeric limits or waste load allocations Watershed management plans Other measurable compliance methods TMDL measurable compliance strategies and toolboxes vary for the pollutant types

10 TMDLs are Enforceable Individual Permits General Permits Construction Industrial Small MS4s Watershed Mandates 5/15/2017

11 Probably Sources

12 Decisions/Steps on TMDL Participation Review 303(d) List Stakeholder Notification Participation in Process Preliminary Project Report Final Report and TMDL Plan TMDL Compliance and Tracking MS4 Runoff List Pollutants Status of TMDLs Respond to requests for data MS4 a source and contributor of pollutant? Review Technical Reports Tech and Stakeholder Committees Comment Review and Submit Comments Discuss Issues Directly with TMDL Staff Review and Submit Comments Work with Other Stakeholders Submit Annual Report Compliance Strategies

13 Global Concerns - Future Efforts Future of TMDLs - what will this program look like? Multiple 303(d) listings for virtually all waterways: bacteria, metals, trash, etc. Total cost requirements: structural + operation and maintenance (O&M)? Suggested Improvements Consistent/coordinated Appropriate Water Quality Standards Longer implementation schedules Prioritization

14 Determination of Significance (Reach Prioritization factors by MS4) Impairment Status MS4 Contributing Drainage Area Connectivity to Receiving Waters Other factors Cooperative efforts with other dischargers Multiple TMDLs addressed by BMP TMDL deadlines specified Regulatory Agency Priority Safety considerations, and Multi-benefit projects contribute to water quality improvement LA River Subwatersheds Draining to Reaches

15 The Compliance Objectives Comply with TMDLs (not subject to Maximum Extent Practicable, or MEP) Implement Integrated solutions - multiple benefits Water Quality, Flood Control, Water Supply, Restoration Address TMDL Commitments Maximize project post-construction Source/Institutional Controls and pollution prevention Watershed approaches BMP Retrofit watershed scale or local BMP retrofit

16 Compliance Strategies (Examples) METALS SEDIMENTS BACTERIA NUTRIENTS Source Control Studies Source Control - erosion and sediment control Eliminate Dry Weather Runoff, Diversion to Sewer Source Control Publicly Owned Treatment Works Controls Infiltration Media Filter Low Impact Development Bioretention Infiltration Detention Low Impact Development Biofiltration Infiltration Low Impact Development Bioretention Ultraviolet Treatment Infiltration Wetbasins Constructed Wetlands Low Impact Development Watershed approach Regional, Multi-benefit Watershed Approach Regional, Multi-benefit Watershed Approach Regional, Studies Watershed approach Inlake Treatment

17 Actions Leading to Compliance (Example of Credits ) Stand-alone BMP retrofits Cooperative implementation Post-construction treatment beyond permit requirements Other pollution reduction practices Institutional controls, public education, source control Innovative approaches stormwater banking, pollutant-trading, off-site mitigation, off-site source control quantitatively demonstrated equal/greater benefit than BMPs. Watershed Implementation Plans (holistic approach)

18 Watershed Programs Focused on TMDLs Chesapeake Bay TMDL Watershed Implementation Plans (WIPs) San Diego Region Water Quality Improvement Plans (WQIPs) Los Angeles Region Enhanced Watershed Management Plans (EWMPs) NPDES Permits have TMDLs - Phase I, Phase II Small MS4s

19 Identify the sources of the pollutants and the beneficial uses of the receiving water

20 BMP Implementation Over Time

21 iwatr Process BMP Retrofit Optimization (what, how, where?)

22 Treatment BMPs (Stormwater Devices) Detention Basins or Infiltration Basins Media Filter Biofilter Strip/Infiltration Trench Media Filter - Earthen

23 More Structural BMPs Floodplain restoration Pervious Pavement with Infiltration Bed Rain Gardens/Bioretention Vegetated Swales Wet Ponds Infiltration Berm and Retentive Grading Rain Garden Bioretention Urban Areas Pervious Pavement

24 Copper TMDLs and BMP Performance Total Copper Compared to LA Region TMDLs 24

25 iwatr.com

26 Upon entering a location, iwatr delineates the watershed and provides impairment issues.

27 Watershed-wide restoration options are available when enabled under Step 3. Once a Land Use and size is selected: iwatr provides pollution risks and ascertains appropriate BMPs. Estimated Construction and O & M cost and treatment footprint are provided for selected BMP.

28 Summary Results Report Location Receiving Water info BMP options Concept Engineering info Hydrologic Soils Pollutant (High/Med/Low) BMP footprint Cost Stormwater Harvest/Use Watershed Options Schematics

29 How is iwatr helpful? Comprehensive national engineering tool focused on improving water quality User-friendly and readily available (website or mobile app) Access publicly available data needed to make sound decisions on concepts (175 GB of data accessible) Rainfall, soils, land use, receiving water, topographic/aerial data Provides decision makers, policy makers and the general public information about their watershed Automated data and water quality structure design concept Scalability (local, state, national) Jump-start long-term ideas based on current and future watershed concerns Engineers and Planners - Concepts, feasibility Grant applications (concepts to submit for funding) Watershed Plans for implementation of BMP Retrofit

30 Website: iwatr.com or Go mobile search location! iwatr.com and enter address or location Apple itunes App Android App Uses location search (like maps ) Switch to street maps, aerial/satellite, hybrid

31 Regional BMP Watershed Retrofit

32 Neighborhood Scale BMP Retrofit Characteristic BMP Type Capital Cost (O&M) BMP Size Description Bioretention Sub regional $474,000 ($17,000/year O&M) 0.5 Acre BMP Footprint 45 Acre Drainage Area

33 Turn Concepts into Operational BMPs Detention Basins or Infiltration Basins Media Filter Biofilter Strip/Infiltration Trench Media Filter - Earthen

34 NPDES permitting authorities should consider incorporating asset management provisions into their NPDES permits to ensure permittees implement sound system operation and maintenance practices.and meet water quality protection requirements.

35 Drivers for (NPDES Permit) Asset Management Phase II MS4 Order DWQ Phase I MS4 SF Bay Order R CT Order DWQ OC OrderR many more.

36 Innovative Information Technology Asset Management and TMDL Compliance Tracking Web-based tracking inventory Mobile tools data collection, inspections, photo documentation Drones- watershedscale and regionalscale inventory

37 Questions? Anna Lantin, P.E. THANK YOU!