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NYS Department of Environmental Conservation NYSDEC Stormwater Permits TMDL Conditions and Retrofit Options Shohreh Karimipour, P.E.

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Presentation on theme: "NYS Department of Environmental Conservation NYSDEC Stormwater Permits TMDL Conditions and Retrofit Options Shohreh Karimipour, P.E."— Presentation transcript:

1 NYS Department of Environmental Conservation NYSDEC Stormwater Permits TMDL Conditions and Retrofit Options Shohreh Karimipour, P.E.

2 NYS Department of Environmental Conservation NY- Status of Stormwater Permits Construction (6860) & MS4 (500) –Renewed April 2008 –2 year term –Detailed and prescriptive –Address TMDL watersheds –Differentiate Non-Traditional/Land use MS4s Multi Sector (1200) No Exposure (550)

3 NYS Department of Environmental Conservation NY- Status of Stormwater Permits One Phase 1 MS4s (NYC) 495 Phase 2 MS4 354 annual reports (2008) indicate –275 Adopted Construction Law –305 Inter-municipal cooperation –48 Received public comments –302 Started plan review –304 Completed outfall mapping MS4 Permit s City, Town, Village412 County33 Federal, State25 School District14 Other Entities16

4 NYS Department of Environmental Conservation NY- Status of Stormwater Manuals Standards and Specification for E&SC SW Management Design Manual –Redevelopment Projects –Enhanced Phosphorus Removal Better Site Design Decompaction Guidance Manual For Local Officials –MS4 Model Laws –Poll. Prevention –Mapping Guidance

5 NYS Department of Environmental Conservation MS4 Permit & TMDL Designation of additional MS4s in TMDL watersheds Extend past areas to boundaries of New York City drinking water watershed East of Hudson Extend Eastward in Long Island Peconic Estuary TMDL designates Eastern Long Island

6 NYS Department of Environmental Conservation Additionally Designated Areas Criterion 1: MS4s discharging to waters for which an EPA-approved TMDL required reduction of a pollutant associated with stormwater beyond what can be achieved with existing programs (and the area is not already covered under automatic designation as UA).

7 NYS Department of Environmental Conservation

8 NYC EOH Watershed Improvement Strategy Local Requirement for E&SC - 5,000 ft 2 to 1 acre (12/31/2009) Local SWPPP Review Against Enhanced P Removal (9/30/2008) Map entire storm sewer system over 5 years Retrofit plan and schedule 3/9/2009 (alone), 12/31/2009 (RSE) Septic Inspections, Maintenance, and Rehabilitation/3 Yr. Targeted Education and Outreach Specific System Maintenance Requirements Specific Turf Management Requirements Leaf and Yard Waste Control Requirements

9 NYS Department of Environmental Conservation

10 Loading Assessments By 1/8/2013 model relative changes in load to impaired waters (no TMDL) with non- negligible changes to land areas or practices By 1/8/2013 model to assess progress in reducing the pollutant of concern to meet TMDL Modeling alternatives in responsiveness summary (Appendix D)

11 NYS Department of Environmental Conservation Standard Unified Sizing Criteria (Chapter 4 Design Manual)  Water Quality Volume (WQv) – Treat 90 % storm  Channel Protection Volume (CPv) – Detain 1 yr storm  Overbank Flood Flow (Qp) - 10 yr storm, post flow rate less than or equal to predevelopment flow rate  Extreme Storm Flow (Qf) yr storm, post flow rate less than or equal to predevelopment flow rate

12 NYS Department of Environmental Conservation Enhanced Phosphorus Removal Sizing Criteria Sizing Criteria for Enhanced Phosphorus Removal Water Quality (WQ v ) WQ v = estimated runoff volume (acre- feet) resulting from the 1-year, 24-hour design storm over the post development watershed Evaluate and implement hydrologic source control where feasible Quantity Controls (Cpv, Q p, Q f ) Refer to existing requirements *Cpv Integrated in extended detention systems Need additional storage in flow through systems.

13 NYS Department of Environmental Conservation Retrofits Retrofits are modifications or additions to existing infrastructure to reduce pollutant loadings. Examples (pp72 and 73): –Better Site Design Approaches –Storm Sewer Rehabilitation –Stabilizing Dirt Roads –Conversion of Dirt Parking to Pervious Pavement –Conversion of Dry Ponds to Detention Ponds or Wetlands –Converting Abandoned Buildings to Open Space or SMP –Control of Downstream Erosion Effects –Direct Control Erosion Effects (Plunge Pool, Velocity Dissipaters) –Upgrade of Existing Conveyance to Provide Quality and Quantity Control –Reforestation

14 NYS Department of Environmental Conservation Retrofit Permit Requirements in April, 08 MS4 Permit Identify sites with problems Choose projects based on: –Pollutant reduction potential –Use of proven technologies –Economic feasibility Procedures for design, permits, funding, O&M Approvable plans, schedules and funding sources

15 NYS Department of Environmental Conservation Retrofit Permit Requirement In April, 08 MS4 Permit East of Hudson MS4s acting alone submit approvable plan and schedule by March 9, 2009 East of Hudson MS4s in RSE submit by December 31, 2009 Onondaga, Greenwood Lake, Oyster Bay, Peconic MS4s submit by March 9, 2011

16 NYS Department of Environmental Conservation DEC Retrofit/Modeling Paper Basis for Retrofit Section of TMDL Implementation Short term expectations: simpler retrofits- e.g. ditches to dry swales, erosion repairs and disconnecting rooftops ~ lb/acre/yr Long term expectations: more sophisticated retrofits - more sophisticated targeting - considering cost effectiveness Load reductions for retrofits can be assigned using WTM or Win-SLAMM

17 NYS Department of Environmental Conservation Other Key Points Older TMDLs do not distinguish MS4 loads from non-point source MS4 load reduction would be achieved with Retrofits and non-structural BMPs Retrofits may include Redevelopment or routine system upgrades Guidance: Urban Stormwater Retrofit Practices Manual Desktop Assessment & Retrofit Reconnaissance Investigation

18 NYS Department of Environmental Conservation East of Hudson TMDL Implementation Plan EPA required EOH Plan First draft public review in 2006 First deadline for retrofit plan in EOH Implementation plan would provide direction for what would be approvable Follow similar process for other watersheds

19 NYS Department of Environmental Conservation East of Hudson TMDL Implementation Plan Concepts Establish sustainable annual mass reductions and maximum 15 year schedule Apportion reductions by MS4 – for Phosphorus, base apportions on high intensity development Allow for bubble or individual load reductions Reductions credited based on modeling projects Re-evaluate every five years ( use monitoring data/modeling)

20 NYS Department of Environmental Conservation Greenwood Lake Watershed Improvement Strategy Local SWPPP Review Using Enhanced P Removal by 9/30/2008 Watershed Based Retrofit plan and schedule 3/9/2011 Septic Inspections, Maintenance, and Rehabilitation/3 Yr Targeted Education and Outreach

21 NYS Department of Environmental Conservation

22 Onondaga Lake Watershed Improvement Strategy Local SWPPP Review Using Enhanced P Removal by 9/30/2008 Watershed Based Retrofit plan and schedule 3/9/2011 Targeted Education and Outreach

23 NYS Department of Environmental Conservation

24 Oyster Bay and Peconic Watershed Improvement Strategy (Pathogens) Watershed Based Retrofit plan and schedule by 3/9/2011 Septic Inspections, Maintenance, and Rehabilitation/ 3 Yr Targeted Education and Outreach Pet Waste Control Goose Population Management

25 NYS Department of Environmental Conservation

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27 Peconic Watershed Improvement Strategy (Nitrogen) Watershed Based Retrofit plan and schedule by 3/9/2011 Septic Inspections, Maintenance, and Rehabilitation/3 yr. Targeted Education and Outreach Specific Turf Management Requirements

28 NYS Department of Environmental Conservation

29 Other TMDL Implementation Plans EPA required TMDL Plans Follow similar process for other watersheds Potential change of criteria at end point Mostly phosphorus limited watersheds –Albany area, Monroe Co., down state Implementation plan would provide direction for what would be approvable

30 NYS Department of Environmental Conservation Questions


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