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NYSDEC Stormwater Permits TMDL Conditions and Retrofit Options. Shohreh Karimipour, P.E. MS4 Permit & TMDL. Designation of additional MS4s in TMDL watersheds 2003 - Extend past areas to boundaries of New York City drinking water watershed East of Hudson 2003 - Extend Eastward in Long Island
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NYSDEC Stormwater Permits TMDL Conditions and Retrofit Options Shohreh Karimipour, P.E.
MS4 Permit & TMDL • Designation of additional MS4s in TMDL watersheds • 2003 - Extend past areas to boundaries of New York City drinking water watershed East of Hudson • 2003 - Extend Eastward in Long Island • 2008 - Peconic Estuary TMDL designates Eastern Long Island
NYC EOH Watershed Improvement Strategy Local Requirement for E&SC - 5,000 ft2 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
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)
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
Retrofit Permit Requirementsin 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
Retrofit Permit RequirementIn 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
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 ~ 0.3 - 0.5 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
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
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)
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
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
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
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
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