J_2024 05 09_West Orange Stormwater Management Plan

Post-Developed (O-1B) West Orange HydroCAD_Post NOAA 24-hr D 2-Year_Current Rainfall=3.45", P2=3.45" Prepared by Burns & McDonnell HydroCAD® 10.20-4b s/n 08510 © 2023 HydroCAD Software Solutions LLC Hydrograph for Subcatchment 7S: PO-DA E Time Precip. Excess (hours) (inches) (inches) 0.00 0.00 0.00 0.50 0.02 0.00 1.00 0.04 0.00 1.50 0.06 0.00 2.00 0.08 0.00 2.50 0.11 0.00 3.00 0.13 0.00 3.50 0.16 0.00 4.00 0.18 0.00 4.50 0.21 0.00 5.00 0.24 0.00 5.50 0.26 0.00 6.00 0.29 0.00 6.50 0.33 0.00 7.00 0.36 0.01 7.50 0.40 0.01 8.00 0.45 0.02 8.50 0.50 0.03 9.00 0.55 0.05 9.50 0.61 0.07 10.00 0.68 0.10 10.50 0.77 0.13 11.00 0.90 0.20 11.50 1.09 0.31 12.00 1.65 0.69 12.50 2.36 1.26 13.00 2.55 1.43 13.50 2.68 1.53 14.00 2.77 1.61 14.50 2.84 1.68 15.00 2.90 1.73 15.50 2.95 1.78 16.00 3.00 1.82 16.50 3.05 1.86 17.00 3.09 1.90 17.50 3.12 1.93 18.00 3.16 1.96 18.50 3.19 1.98 19.00 3.21 2.01 19.50 3.24 2.03 20.00 3.27 2.06 20.50 3.29 2.08 21.00 3.32 2.11 21.50 3.34 2.13 22.00 3.37 2.15 22.50 3.39 2.17 23.00 3.41 2.19 23.50 3.43 2.21 24.00 3.45 2.22 Runoff (cfs) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.02 0.02 0.03 0.05 0.08 0.25 0.29 0.12 0.07 0.05 0.05 0.04 0.03 0.03 0.03 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.01 0.01 0.01 0.01 0.01 Printed 5/13/2024 Page 52

Post-Developed (O-1B) NOAA 24-hr D 2-Year_Current Rainfall=3.45", P2=3.45" West Orange HydroCAD_Post Printed 5/13/2024 Page 53 Prepared by Burns & McDonnell HydroCAD® 10.20-4b s/n 08510 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment 9S: PO-DA G Runoff = 0.59 cfs @ 12.33 hrs, Volume= Routed to Pond 3P : BR-03 0.073 af, Depth> 2.26" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-24.00 hrs, dt= 0.0100 hrs NOAA 24-hr D 2-Year_Current Rainfall=3.45", P2=3.45" Area (sf) 4,879 2,788 9,235 16,902 12,023 4,879 * CN 98 80 85 Description Impervious, Pavement, HSG D >75% Grass cover, Good, HSG D Yard Stone/Gravel Pad, HSG D Weighted Average 71.13% Pervious Area 28.87% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 22.6 100 0.0010 0.07 Sheet Flow, Gravel Sheet Flow n= 0.100 P2= 3.45" 0.7 75 0.0121 1.77 Shallow Concentrated Flow, Shallow Concentrated Flow Unpaved Kv= 16.1 fps 23.3 175 Total Subcatchment 9S: PO-DA G Hydrograph 0.65 Runoff 0.59 cfs 0.6 NOAA 24-hr D 2-Year_Current Rainfall=3.45" P2=3.45" Runoff Area=16,902 sf Runoff Volume=0.073 af Runoff Depth>2.26" Flow Length=175' Tc=23.3 min CN=WQ 0.55 0.5 0.45 Flow (cfs) 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Time (hours) 15 16 17 18 19 20 21 22 23 24

Post-Developed (O-1B) West Orange HydroCAD_Post NOAA 24-hr D 2-Year_Current Rainfall=3.45", P2=3.45" Prepared by Burns & McDonnell HydroCAD® 10.20-4b s/n 08510 © 2023 HydroCAD Software Solutions LLC Hydrograph for Subcatchment 9S: PO-DA G Time Precip. Excess (hours) (inches) (inches) 0.00 0.00 0.00 0.50 0.02 0.00 1.00 0.04 0.00 1.50 0.06 0.00 2.00 0.08 0.00 2.50 0.11 0.00 3.00 0.13 0.00 3.50 0.16 0.00 4.00 0.18 0.00 4.50 0.21 0.00 5.00 0.24 0.00 5.50 0.26 0.00 6.00 0.29 0.00 6.50 0.33 0.00 7.00 0.36 0.01 7.50 0.40 0.01 8.00 0.45 0.02 8.50 0.50 0.03 9.00 0.55 0.05 9.50 0.61 0.07 10.00 0.68 0.10 10.50 0.77 0.13 11.00 0.90 0.20 11.50 1.09 0.31 12.00 1.65 0.69 12.50 2.36 1.26 13.00 2.55 1.43 13.50 2.68 1.53 14.00 2.77 1.61 14.50 2.84 1.68 15.00 2.90 1.73 15.50 2.95 1.78 16.00 3.00 1.82 16.50 3.05 1.86 17.00 3.09 1.90 17.50 3.12 1.93 18.00 3.16 1.96 18.50 3.19 1.98 19.00 3.21 2.01 19.50 3.24 2.03 20.00 3.27 2.06 20.50 3.29 2.08 21.00 3.32 2.11 21.50 3.34 2.13 22.00 3.37 2.15 22.50 3.39 2.17 23.00 3.41 2.19 23.50 3.43 2.21 24.00 3.45 2.22 Runoff (cfs) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.02 0.02 0.03 0.05 0.08 0.20 0.45 0.16 0.09 0.06 0.05 0.04 0.04 0.03 0.03 0.03 0.03 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.01 0.01 0.01 Printed 5/13/2024 Page 54

Post-Developed (O-1B) NOAA 24-hr D 2-Year_Current Rainfall=3.45", P2=3.45" West Orange HydroCAD_Post Printed 5/13/2024 Page 55 Prepared by Burns & McDonnell HydroCAD® 10.20-4b s/n 08510 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment 11S: PO-DA I Runoff = 0.59 cfs @ 12.14 hrs, Volume= Routed to Pond 5P : BR-05 0.045 af, Depth> 2.25" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-24.00 hrs, dt= 0.0100 hrs NOAA 24-hr D 2-Year_Current Rainfall=3.45", P2=3.45" Area (sf) 2,904 1,737 5,866 10,507 7,603 2,904 * CN 98 80 85 Description Impervious, Pavement, HSG D >75% Grass cover, Good, HSG D Yard Stone/Gravel Pad, HSG D Weighted Average 72.36% Pervious Area 27.64% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.4 100 0.0237 0.26 Sheet Flow, Gravel Sheet Flow n= 0.100 P2= 3.45" 0.1 20 0.0320 2.88 Shallow Concentrated Flow, Shallow Concentrated Flow Unpaved Kv= 16.1 fps 6.5 120 Total Subcatchment 11S: PO-DA I Hydrograph Runoff 0.65 0.59 cfs 0.6 NOAA 24-hr D 2-Year_Current Rainfall=3.45" P2=3.45" Runoff Area=10,507 sf Runoff Volume=0.045 af Runoff Depth>2.25" Flow Length=120' Tc=6.5 min CN=WQ 0.55 0.5 0.45 Flow (cfs) 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Time (hours) 15 16 17 18 19 20 21 22 23 24

Post-Developed (O-1B) West Orange HydroCAD_Post NOAA 24-hr D 2-Year_Current Rainfall=3.45", P2=3.45" Prepared by Burns & McDonnell HydroCAD® 10.20-4b s/n 08510 © 2023 HydroCAD Software Solutions LLC Hydrograph for Subcatchment 11S: PO-DA I Time Precip. Excess (hours) (inches) (inches) 0.00 0.00 0.00 0.50 0.02 0.00 1.00 0.04 0.00 1.50 0.06 0.00 2.00 0.08 0.00 2.50 0.11 0.00 3.00 0.13 0.00 3.50 0.16 0.00 4.00 0.18 0.00 4.50 0.21 0.00 5.00 0.24 0.00 5.50 0.26 0.00 6.00 0.29 0.00 6.50 0.33 0.00 7.00 0.36 0.01 7.50 0.40 0.01 8.00 0.45 0.02 8.50 0.50 0.03 9.00 0.55 0.05 9.50 0.61 0.07 10.00 0.68 0.10 10.50 0.77 0.13 11.00 0.90 0.20 11.50 1.09 0.31 12.00 1.65 0.69 12.50 2.36 1.26 13.00 2.55 1.43 13.50 2.68 1.53 14.00 2.77 1.61 14.50 2.84 1.68 15.00 2.90 1.73 15.50 2.95 1.78 16.00 3.00 1.82 16.50 3.05 1.86 17.00 3.09 1.90 17.50 3.12 1.93 18.00 3.16 1.96 18.50 3.19 1.98 19.00 3.21 2.01 19.50 3.24 2.03 20.00 3.27 2.06 20.50 3.29 2.08 21.00 3.32 2.11 21.50 3.34 2.13 22.00 3.37 2.15 22.50 3.39 2.17 23.00 3.41 2.19 23.50 3.43 2.21 24.00 3.45 2.22 Runoff (cfs) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.01 0.01 0.01 0.01 0.02 0.02 0.04 0.06 0.30 0.13 0.07 0.04 0.04 0.03 0.02 0.02 0.02 0.02 0.02 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 Printed 5/13/2024 Page 56

Post-Developed (O-1B) NOAA 24-hr D 2-Year_Current Rainfall=3.45", P2=3.45" West Orange HydroCAD_Post Printed 5/13/2024 Page 57 Prepared by Burns & McDonnell HydroCAD® 10.20-4b s/n 08510 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment 12S: PO-DA J Runoff = 0.83 cfs @ 12.13 hrs, Volume= Routed to Pond 6P : BR-04 0.062 af, Depth> 2.35" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-24.00 hrs, dt= 0.0100 hrs NOAA 24-hr D 2-Year_Current Rainfall=3.45", P2=3.45" Area (sf) 5,314 3,703 4,792 13,809 8,495 5,314 * CN 98 80 85 Description Impervious, Pavement, HSG D >75% Grass cover, Good, HSG D Yard Stone/Gravel Pad, HSG D Weighted Average 61.52% Pervious Area 38.48% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.4 96 0.0336 0.30 Sheet Flow, Gravel Sheet Flow n= 0.100 P2= 3.45" Subcatchment 12S: PO-DA J Hydrograph Runoff 0.9 0.83 cfs 0.85 NOAA 24-hr D 2-Year_Current Rainfall=3.45" P2=3.45" Runoff Area=13,809 sf Runoff Volume=0.062 af Runoff Depth>2.35" Flow Length=96' Slope=0.0336 '/' Tc=5.4 min CN=WQ 0.8 0.75 0.7 0.65 Flow (cfs) 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Time (hours) 15 16 17 18 19 20 21 22 23 24

Post-Developed (O-1B) West Orange HydroCAD_Post NOAA 24-hr D 2-Year_Current Rainfall=3.45", P2=3.45" Prepared by Burns & McDonnell HydroCAD® 10.20-4b s/n 08510 © 2023 HydroCAD Software Solutions LLC Hydrograph for Subcatchment 12S: PO-DA J Time Precip. Excess (hours) (inches) (inches) 0.00 0.00 0.00 0.50 0.02 0.00 1.00 0.04 0.00 1.50 0.06 0.00 2.00 0.08 0.00 2.50 0.11 0.00 3.00 0.13 0.00 3.50 0.16 0.00 4.00 0.18 0.00 4.50 0.21 0.00 5.00 0.24 0.00 5.50 0.26 0.00 6.00 0.29 0.00 6.50 0.33 0.00 7.00 0.36 0.01 7.50 0.40 0.02 8.00 0.45 0.03 8.50 0.50 0.04 9.00 0.55 0.06 9.50 0.61 0.08 10.00 0.68 0.11 10.50 0.77 0.16 11.00 0.90 0.22 11.50 1.09 0.34 12.00 1.65 0.75 12.50 2.36 1.33 13.00 2.55 1.50 13.50 2.68 1.61 14.00 2.77 1.69 14.50 2.84 1.76 15.00 2.90 1.81 15.50 2.95 1.86 16.00 3.00 1.90 16.50 3.05 1.94 17.00 3.09 1.98 17.50 3.12 2.01 18.00 3.16 2.04 18.50 3.19 2.07 19.00 3.21 2.09 19.50 3.24 2.12 20.00 3.27 2.14 20.50 3.29 2.17 21.00 3.32 2.19 21.50 3.34 2.21 22.00 3.37 2.23 22.50 3.39 2.26 23.00 3.41 2.27 23.50 3.43 2.29 24.00 3.45 2.31 Runoff (cfs) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.02 0.03 0.03 0.05 0.09 0.44 0.17 0.09 0.06 0.05 0.04 0.03 0.03 0.03 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 Printed 5/13/2024 Page 58

Post-Developed (O-1B) NOAA 24-hr D 2-Year_Current Rainfall=3.45", P2=3.45" West Orange HydroCAD_Post Prepared by Burns & McDonnell HydroCAD® 10.20-4b s/n 08510 © 2023 HydroCAD Software Solutions LLC Printed 5/13/2024 Page 59 Summary for Pond 1P: BR-01 Inflow Area = 0.567 ac, 17.46% Impervious, Inflow Depth > 2.14" for 2-Year_Current event Inflow = 0.93 cfs @ 12.27 hrs, Volume= 0.101 af Outflow = 0.24 cfs @ 12.86 hrs, Volume= 0.099 af, Atten= 74%, Lag= 35.1 min Primary = 0.24 cfs @ 12.86 hrs, Volume= 0.099 af Routed to Pond 19P : SD-21 Routing by Dyn-Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.0100 hrs Peak Elev= 598.20' @ 12.86 hrs Surf.Area= 5,277 sf Storage= 1,470 cf Plug-Flow detention time= 76.9 min calculated for 0.099 af (98% of inflow) Center-of-Mass det. time= 66.2 min ( 888.6 - 822.4 ) Volume #1 #2 Invert 598.00' 597.50' Avail.Storage 5,850 cf 330 cf #3 596.00' 1,051 cf #4 596.00' 11 cf 7,241 cf Storage Description Filter Media Layer (Prismatic)Listed below (Recalc) Sand Layer (Prismatic)Listed below (Recalc) 880 cf Overall x 37.5% Voids Gravel Layer (Prismatic)Listed below (Recalc) 2,639 cf Overall - 11 cf Embedded = 2,627 cf x 40.0% Voids 4.0" Round 4" Underdrain Pipe Inside #3 L= 127.3' S= 0.0001 '/' Total Available Storage Elevation (feet) 598.00 599.50 602.50 Surf.Area Voids (sq-ft) (%) 1,759 0.0 1,759 21.7 1,759 100.0 Elevation (feet) 597.50 598.00 Surf.Area (sq-ft) 1,759 1,759 Inc.Store (cubic-feet) 0 880 Cum.Store (cubic-feet) 0 880 Elevation (feet) 596.00 597.50 Surf.Area (sq-ft) 1,759 1,759 Inc.Store (cubic-feet) 0 2,639 Cum.Store (cubic-feet) 0 2,639 Device #1 Routing Primary Invert 591.57' #2 Device 1 596.00' #3 Device 1 600.50' #4 Device 1 602.40' Inc.Store (cubic-feet) 0 573 5,277 Cum.Store (cubic-feet) 0 573 5,850 Outlet Devices 12.0" Vert. SD-21 Outlet (Elevation F) C= 0.600 Limited to weir flow at low heads 2.5" Vert. Water Quatity (Elevation G) C= 0.600 Limited to weir flow at low heads 12.0" W x 2.5" H Vert. Water Quantity (Elevation H) C= 0.600 Limited to weir flow at low heads 48.0" x 48.0" Horiz. Overflow Grate (Elevation I) C= 0.600 Limited to weir flow at low heads

Post-Developed (O-1B) NOAA 24-hr D 2-Year_Current Rainfall=3.45", P2=3.45" West Orange HydroCAD_Post Printed 5/13/2024 Page 60 Prepared by Burns & McDonnell HydroCAD® 10.20-4b s/n 08510 © 2023 HydroCAD Software Solutions LLC Primary OutFlow Max=0.24 cfs @ 12.86 hrs HW=598.20' TW=590.85' (Dynamic Tailwater) 1=SD-21 Outlet (Elevation F) (Passes 0.24 cfs of 9.37 cfs potential flow) 2=Water Quatity (Elevation G) (Orifice Controls 0.24 cfs @ 6.98 fps) 3=Water Quantity (Elevation H) ( Controls 0.00 cfs) 4=Overflow Grate (Elevation I) ( Controls 0.00 cfs) Pond 1P: BR-01 Hydrograph Inflow Primary 0.93 cfs 1 Flow (cfs) Inflow Area=0.567 ac Peak Elev=598.20' Storage=1,470 cf 0.24 cfs 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Time (hours) 15 16 17 18 19 20 21 22 23 24

Post-Developed (O-1B) West Orange HydroCAD_Post NOAA 24-hr D 2-Year_Current Rainfall=3.45", P2=3.45" Prepared by Burns & McDonnell HydroCAD® 10.20-4b s/n 08510 © 2023 HydroCAD Software Solutions LLC Hydrograph for Pond 1P: BR-01 Time (hours) 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 6.00 6.50 7.00 7.50 8.00 8.50 9.00 9.50 10.00 10.50 11.00 11.50 12.00 12.50 13.00 13.50 14.00 14.50 15.00 15.50 16.00 16.50 17.00 17.50 18.00 18.50 19.00 19.50 20.00 20.50 21.00 21.50 22.00 22.50 23.00 23.50 24.00 Inflow (cfs) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.01 0.01 0.01 0.01 0.02 0.02 0.03 0.04 0.06 0.12 0.33 0.53 0.20 0.12 0.09 0.07 0.06 0.05 0.05 0.04 0.04 0.04 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.02 0.02 0.02 0.02 0.02 0.02 Storage Elevation (cubic-feet) (feet) 0 596.00 0 596.00 0 596.00 0 596.00 1 596.00 4 596.01 7 596.01 11 596.02 15 596.02 19 596.03 23 596.03 26 596.04 29 596.04 31 596.04 34 596.05 38 596.05 43 596.06 50 596.07 58 596.08 68 596.09 82 596.11 100 596.14 126 596.17 186 596.26 374 596.52 1,317 597.89 1,459 598.18 1,326 597.90 1,129 597.60 930 597.31 745 597.05 576 596.81 435 596.61 325 596.45 242 596.34 183 596.25 143 596.20 118 596.16 106 596.15 100 596.14 96 596.13 93 596.13 91 596.13 89 596.12 87 596.12 85 596.12 83 596.12 81 596.11 79 596.11 Primary (cfs) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.01 0.01 0.01 0.02 0.02 0.03 0.04 0.06 0.11 0.22 0.24 0.22 0.20 0.18 0.16 0.14 0.12 0.10 0.08 0.06 0.05 0.04 0.03 0.03 0.03 0.03 0.03 0.03 0.02 0.02 0.02 0.02 0.02 Printed 5/13/2024 Page 61