suny esf workshop shohreh karimipour, p.e. enhanced phosphorus removal standards new york state...
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SUNY ESF Workshop
Shohreh Karimipour, P.E.
Enhanced Phosphorus
Removal Standards
Enhanced Phosphorus
Removal Standards
NEW YORK STATE DEPARTMENT OF ENVIRONMENTAL CONSERVATION
PurposePurpose• To develop an effective and
technically defensible criteria to address stormwater design standards in phosphorus-limited watersheds– EOH NYC Water Supplies Watersheds
– Greenwood Lake
– Onondaga Lake
• A supplement to the Existing New York State Stormwater Management Design Manual for enhanced phosphorus control– Provide consistency with NYCDEP watershed rules
– Enhanced Criteria consistent with the current State standards
OverviewOverview• Existing Stormwater Design
Standards– New York State – Watershed Rules
• Enhanced Standards (Supplement)– Defining Enhanced Phosphorus Removal– Overview of Development Process– Recommendations
• Design Standards– Sizing Criteria– Performance Criteria
Marcus Quigley, P.E. Project Manager Eric Strecker, Principal-In-Charge GeoSyntec Consultants
Robert Pitt, Senior Technical Specialist and Technical Review
NYS DEC, Project Management
Technical Advisory Group (TAG)NYCDEPNYSSWCCNYSOAGRiver Keepers (CEA)Insite Engineering
The Project Team
University of Alabama
Design StandardsNYS RequirementsDesign StandardsNYS Requirements
• Sizing Criteria– Capture & treatment 90% Design Storm– Channel protection and flood controls
• Performance Criteria– Removal Efficiency: 80% TSS 40% phosphorus– Standard management practices– Design Specifications
• Can capture and treat the full water quality volume• Provide pretreatment• Have acceptable longevity in the field
Features of Standard SystemsFeatures of Standard Systems
Examples:• Embankment Specifications• Principal/Emergency Spillway
• Inlet Protection• Adequate Outfall Protection
• Sediment Forebay• Media specifications
• Adequate WQv• Multiple Treatment Pathways• Minimum Geometry
• Pond Benches • Pondscaping Plan• Wetland Elements• Pond Buffers / Setbacks
• Non-clogging Orifice• Riser in Embankment• Adjustable Gate Valve• Safety Features
• Maintenance Responsibility• Maintenance Access• Maintenance Schedule
Watershed RulesWatershed Rules
• The Croton Watershed– Sizing Criteria
• Detention of 2-yr., 24-hr. storm• TR-55 calculation method• Pollutant load analysis• 2-yr, 10-yr, 25-yr, 100-yr peak control
– Performance Criteria• infiltration, retention, detention
• Onondaga Lake• Greenwood Lake
Defining EnhancedDefining Enhanced• Performance Criteria
• How much stormwater is prevented? – Hydrologic Source Control– Evapotranspiration– Infiltration
• How much of the remaining stormwater is treated?
– Hydraulic function– Capture and treatment– Bypass
• What is the effluent quality of the treated runoff?
– Effluent quality of the discharge– Seasonal Performance Criteria
Phosphorus and TreatabilityPhosphorus and Treatability• Particulate vs. dissolved forms• Particulate size or settling
velocities• International BMP Database• Research by Pitt, et al. (Wisconsin)• P association with particles < 10 µm
51,90063,10078,8006,6402,16017,2006,400Average
mgP/kgSS
0.45-1 µm
1-2 µm
2-10 µm
10-45 µm
45-106 µm
106-250 µm
>250 µmParticle size
• Sizing analysis as a function of• Treatment volume • Detention time• Permanent pool• Particle settling theory
– Continuous simulation SWMM modeling
• 44 yr hourly data (Carmel)• 120 Model runs
– Event simulation by HydroCAD®• Detention time• Seven scenarios (WQv)
Permanent Pool
Extended Detention outlet
Channel Prot. outlet
Overbank outlet
Outlet riser
Defining EnhancedMethodologyDefining EnhancedMethodology
Continuous Simulation Analyses Performed to Ascertain Performance
Continuous Simulation Analyses Performed to Ascertain Performance
Hydrologic Processes SWMM Representation
runoff
precipitation
evapotranspiration
infiltration
BMP
Development area
Precipitation (hourly)
Surface runoff hydrograph
ETInfiltration
GW recharge
ET
Impervious areas(runoff block)
Precipitation (hourly)
Stormwater runoff
hydrograph
BMP (Storage treatment block)
Outflow hydrograph (to receiving waters)
Pervious areas(runoff block)
Disconnected runoff
Base flows (not considered for Burgundy Rose)
Hydrologic Processes SWMM Representation
runoff
precipitation
evapotranspiration
infiltration
BMP
Development area
runoff
precipitation
evapotranspiration
infiltration
BMP
Development area
Precipitation (hourly)
Surface runoff hydrograph
ETInfiltration
GW recharge
ET
Impervious areas(runoff block)
Precipitation (hourly)
Stormwater runoff
hydrograph
BMP (Storage treatment block)
Outflow hydrograph (to receiving waters)
Pervious areas(runoff block)
Disconnected runoff
Base flows (not considered for Burgundy Rose)
Precipitation (hourly)
Surface runoff hydrograph
ETInfiltration
GW recharge
ET
Impervious areas(runoff block)
Precipitation (hourly)
Stormwater runoff
hydrograph
BMP (Storage treatment block)
Outflow hydrograph (to receiving waters)
Pervious areas(runoff block)
Disconnected runoff
Base flows (not considered for Burgundy Rose)
Median particle size distribution
35%
40%
45%
50%
55%
60%
65%
70%
75%
80%
85%
90%
95%
100%
0.5 2.0 3.5 5.0 6.5 8.0 9.5 11.0 12.5 14.0 15.5 17.0 18.5 20.0
WQv (af)
% P
arti
cula
te P
ho
sph
oro
us
Cap
ture
25% PP - 24hr drawdown 25% PP - 48hr drawdown 25% PP - 72hr drawdown
50% PP - 24hr drawdown 50% PP - 48hr drawdown 50% PP - 72hr drawdown
Current design standard (WQv = 1.35 ac-ft)
1-year 24-hour (WQv = 5.33 ac-ft)
2-year 24-hour (WQv = 8.08 ac-ft)
Wet Extended Detention Pond (Particulate Phosphorous Treatment)
Extended Detention PondExtended Detention Pond
1yr
- Im
pe
rv
2x1
yr
- Im
pe
rv
2p
ctI
A -
Im
pe
rv
2yr
- Im
pe
rv
4x9
0p
ct
- Im
perv
DE
C -
Im
pe
rv
NY
CD
EP
- Im
pe
rv
1yr
- P
erv
2x1
yr
- P
erv
2p
ctI
A -
Perv
2yr
- P
erv
4x9
0p
ct
- P
erv
DE
C -
Perv
NY
CD
EP
- P
erv
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Particulate-associated Phosphorus
% P
art
icu
late
Ph
osp
ho
rus C
ap
ture
1yr - Imperv 2x1yr - Imperv 2pctIA - Imperv 2yr - Imperv 4x90pct - Imperv DEC - Imperv NYCDEP - Imperv
1yr - Perv 2x1yr - Perv 2pctIA - Perv 2yr - Perv 4x90pct - Perv DEC - Perv NYCDEP - Perv
Impervious Pervious
Infiltration SystemsInfiltration Systems
DE
C -
Im
pe
rv
1y
r -
Imp
erv
2y
r -
Imp
erv
DE
C -
Pe
rv
1y
r -
Pe
rv
2y
r -
Pe
rv
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Infiltration System Sizing Method
Perc
en
t fl
ow
vo
lum
e t
reatm
en
t
DEC - Imperv 1yr - Imperv 2yr - Imperv DEC - Perv 1yr - Perv 2yr - Perv
Impervious Pervious
• 1 year-24 hour Sizing Method estimated to achieve > 80% treatment for both storage and flow through systems.
• Decreasing marginal gain in treatment performance as WQv size increases
• Results in– Alternative that modifies WQv sizing– Use of TR-55/TR-20 methods– Incorporate physical characteristics of the site
RecommendationRecommendation
Performance Goals: source controlPerformance Goals: source control
Goal 1 - Reduce runoff volumes to the maximum extent practicable– Hydrologic Source Control– Evapotranspiration– Infiltration
• Infiltration Requirement– Infiltration credit– Incorporate soil in sizing– Site evaluation
Percentage of Impervious area routed through BSD
Hydrologic Soil Group
% Impervious area
A
30%
B
20%
C
10%
D 5%
Performance Goals: source controlPerformance Goals: source control
• Evaluation Requirements
– Imp. area disconnection
– Standard Infiltration
– Better Site Design– Low Impact Development– Green infrastructure– Sustainable Ecosystem
Better Site DesignBetter Site Design
Preserve undisturbed areas
Conservation Design
An approach to development An approach to development design design
that seeks to:that seeks to:
Better Site DesignBetter Site Design
Reduce impervious cover
Roads Parking lots Driveways
An approach to development An approach to development design design
that seeks to:that seeks to:
Better Site DesignBetter Site Design
Use pervious areas for stormwater treatment
An approach to development An approach to development design that seeks to:design that seeks to:
Performance Goals: source controlPerformance Goals: source control
• Post Construction
– Increased Curve Number– Soil Decompaction
• Deep Ripping• Decompaction
• Resourceshttp://www.dec.ny.gov/chemical/8694.html
• Goal 2 - Achieve less than 15% effective treatment bypass of the long term runoff volume.– Focus on hydraulic control– Capture and treatment– Bypass
• Simulated hydraulic function in SWMM• Applied design in TR-55, TR-20
Performance Goals: sizing criteriaPerformance Goals: sizing criteria
Sizing CriteriaSizing CriteriaSizing 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
ApplicationApplication• Precipitation Data
– Source of Isographs of Design Storms• TP-40• North East Climate Center Atlas of Precipitation Extremes
– Storm distribution
• Examples– Storage– Flow through– BSD
Good Drainage ParadigmGood Drainage Paradigm
Conventional Site DesignConventional Site Design
Collect Collect Concentrate Concentrate Convey Convey Centralized Centralized ControlControl
Credit: HWG
Rain Garden Rain Garden
Treatment Train ApproachTreatment Train Approach
Bioretention CellStorm Drain System
Bioretention CellFlow Path
Grass Swale Grass Filter Strip
Credit: HWG
Quantity ControlsQuantity Controls
• Channel Protection– 24 hour detention of 1 year, 24 hr storm
• Integrated in extended detention systems
• Need additional storage in flow through systems.
• Flood Control– 10 & 100 year control not exceeding pre
construction peak discharge.
• Goal 3 – median effluent concentration of particulate phosphorus shall be at or below 0.1 mg/L
• Goal 4 - median effluent concentration of dissolved phosphorus shall be at or below 0.06 mg/L– Effluent quality of the discharge– International Stormwater
BMP Database
http://www.bmpdatabase.org– Research by Pitt, et al.
(NSWQ Database)
http://rpitt.eng.ua.edu/Research/
ms4/Paper/Mainms4paper.html
Performance Goals: performance criteriaPerformance Goals: performance criteria
Performance Goals: performance criteriaPerformance Goals: performance criteria
• Performance Specifications: design details not specified in this section shall, at minimum, meet spec. in Chapter 6– Practice options– Design geometry– media specification– optimum vegetative cover– Maintenance
SummarySummary• An effective and technically defensible
criteria to address stormwater design standards in P-limited watersheds consistent with NYCDEP requirements – 1 year-24 hour Sizing Method estimated to
achieve > 80% treatment for both storage and flow through systems.
– Effluent concentration criteria – Hydrologic source control
• Better Site Design• Infiltration requirement
– Improved design specifications– TR-55 calculation method– Update precipitation values