2 NY- Status of Stormwater Permits Construction (6860) & MS4 (500)Renewed April 20082 year termDetailed and prescriptiveAddress TMDL watershedsDifferentiate Non-Traditional/Land use MS4sMulti Sector (1200)No Exposure (550)
3 NY- Status of Stormwater Permits One Phase 1 MS4s (NYC)495 Phase 2 MS4354 annual reports (2008) indicate275 Adopted Construction Law305 Inter-municipal cooperation48 Received public comments302 Started plan review304 Completed outfall mappingMS4PermitsCity, Town, Village412County33Federal, State25School District14Other Entities16
4 NY- Status of Stormwater Manuals Standards and Specification for E&SCSW Management Design ManualRedevelopment ProjectsEnhanced Phosphorus RemovalBetter Site DesignDecompactionGuidance Manual ForLocal OfficialsMS4 Model LawsPoll. PreventionMapping Guidance
5 MS4 Permit & TMDL Designation of additional MS4s in TMDL watersheds Extend past areas to boundaries of New York City drinking water watershed East of HudsonExtend Eastward in Long IslandPeconic Estuary TMDL designates Eastern Long Island
6 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).
8 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 yearsRetrofit plan and schedule 3/9/2009 (alone), 12/31/2009 (RSE)Septic Inspections, Maintenance, and Rehabilitation/3 Yr.Targeted Education and OutreachSpecific System Maintenance RequirementsSpecific Turf Management RequirementsLeaf and Yard Waste Control Requirements
10 Loading AssessmentsBy 1/8/2013 model relative changes in load to impaired waters (no TMDL) with non-negligible changes to land areas or practicesBy 1/8/2013 model to assess progress in reducing the pollutant of concern to meet TMDLModeling alternatives in responsiveness summary (Appendix D)
11 Standard Unified Sizing Criteria (Chapter 4 Design Manual) Water Quality Volume (WQv) – Treat 90 % stormChannel Protection Volume (CPv) – Detain 1 yr stormOverbank Flood Flow (Qp) - 10 yr storm, post flow rate less than or equal to predevelopment flow rateExtreme Storm Flow (Qf) yr storm, post flow rate less than or equal to predevelopment flow rate
12 Enhanced Phosphorus Removal Sizing Criteria Sizing Criteria for Enhanced Phosphorus RemovalWater Quality (WQv)WQv = estimated runoff volume (acre-feet) resulting from the 1-year, 24-hour design storm over the post development watershedEvaluate and implement hydrologic source control where feasibleQuantity Controls (Cpv, Qp, Qf)Refer to existing requirements*CpvIntegrated in extended detention systemsNeed additional storage in flow through systems.
13 RetrofitsRetrofits are modifications or additions to existing infrastructure to reduce pollutant loadings. Examples (pp72 and 73):Better Site Design ApproachesStorm Sewer RehabilitationStabilizing Dirt RoadsConversion of Dirt Parking to Pervious PavementConversion of Dry Ponds to Detention Ponds or WetlandsConverting Abandoned Buildings to Open Space or SMPControl of Downstream Erosion EffectsDirect Control Erosion Effects (Plunge Pool, Velocity Dissipaters)Upgrade of Existing Conveyance to Provide Quality and Quantity ControlReforestation
14 Retrofit Permit Requirements in April, 08 MS4 Permit Identify sites with problemsChoose projects based on:Pollutant reduction potentialUse of proven technologiesEconomic feasibilityProcedures for design, permits, funding, O&MApprovable plans, schedules and funding sources
15 Retrofit Permit Requirement In April, 08 MS4 Permit East of Hudson MS4s acting alone submit approvable plan and schedule by March 9, 2009East of Hudson MS4s in RSE submit by December 31, 2009Onondaga, Greenwood Lake, Oyster Bay, Peconic MS4s submit by March 9, 2011
16 DEC Retrofit/Modeling Paper Basis for Retrofit Section of TMDL ImplementationShort term expectations: simpler retrofits- e.g. ditches to dry swales, erosion repairs and disconnecting rooftops ~ lb/acre/yrLong term expectations: more sophisticated retrofits - more sophisticated targeting - considering cost effectivenessLoad reductions for retrofits can be assigned using WTM or Win-SLAMM
17 Other Key PointsOlder TMDLs do not distinguish MS4 loads from non-point sourceMS4 load reduction would be achieved with Retrofits and non-structural BMPsRetrofits may include Redevelopment or routine system upgradesGuidance: Urban Stormwater Retrofit Practices ManualDesktop Assessment & Retrofit Reconnaissance Investigation
18 East of Hudson TMDL Implementation Plan EPA required EOH PlanFirst draft public review in 2006First deadline for retrofit plan in EOHImplementation plan would provide direction for what would be approvableFollow similar process for other watersheds
19 East of Hudson TMDL Implementation Plan Concepts Establish sustainable annual mass reductions and maximum 15 year scheduleApportion reductions by MS4 – for Phosphorus, base apportions on high intensity developmentAllow for bubble or individual load reductionsReductions credited based on modeling projectsRe-evaluate every five years ( use monitoring data/modeling)
20 Greenwood Lake Watershed Improvement Strategy Local SWPPP Review Using Enhanced P Removal by 9/30/2008Watershed Based Retrofit plan and schedule 3/9/2011Septic Inspections, Maintenance, and Rehabilitation/3 YrTargeted Education and Outreach
24 Oyster Bay and Peconic Watershed Improvement Strategy (Pathogens) Watershed Based Retrofit plan and schedule by 3/9/2011Septic Inspections, Maintenance, and Rehabilitation/ 3 YrTargeted Education and OutreachPet Waste ControlGoose Population Management
27 Peconic Watershed Improvement Strategy (Nitrogen) Watershed Based Retrofit plan and schedule by 3/9/2011Septic Inspections, Maintenance, and Rehabilitation/3 yr.Targeted Education and OutreachSpecific Turf Management Requirements
29 Other TMDL Implementation Plans EPA required TMDL PlansFollow similar process for other watershedsPotential change of criteria at end pointMostly phosphorus limited watershedsAlbany area, Monroe Co., down stateImplementation plan would provide direction for what would be approvable
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