NYS Department of Environmental Conservation NYSDEC Stormwater Permits TMDL Conditions and Retrofit Options Shohreh Karimipour, P.E.
NYS Department of Environmental Conservation
NYSDEC Stormwater Permits TMDL
Conditions and Retrofit Options
Shohreh Karimipour, P.E.
NYS Department of Environmental Conservation
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
NYS Department of Environmental Conservation
NYS Department of Environmental Conservation
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
NYS Department of Environmental Conservation
NYS Department of Environmental Conservation
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)
NYS Department of Environmental Conservation
Enhanced Phosphorus Removal Sizing Criteria
Sizing Criteria for Enhanced Phosphorus Removal
Water Quality (WQv)
WQv = 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, Qp, Qf)
Refer to existing requirements*Cpv
Integrated in extended detention systems
Need additional storage in flow through systems.
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
NYS Department of Environmental Conservation
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
NYS Department of Environmental Conservation
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
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 ~ 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
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
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)
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
NYS Department of Environmental Conservation
NYS Department of Environmental Conservation
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
NYS Department of Environmental Conservation
NYS Department of Environmental Conservation
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
NYS Department of Environmental Conservation
NYS Department of Environmental Conservation
NYS Department of Environmental Conservation
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
NYS Department of Environmental Conservation
NYS Department of Environmental Conservation
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
NYS Department of Environmental Conservation
Questions