Report 4 13 2026

29906 15 Ridgeway West Orange Final NOAA 24-hr D 2-Year-2050 Rainfall=4.09", P2=4.09" Prepared by Ensurplan Inc Printed 4/20/2026 HydroCAD® 10.20-8a s/n 11646 © 2025 HydroCAD Software Solutions LLC Page 21 Summary for Subcatchment 1S: Existing Conditions Study Area Runoff = 0.57 cfs @ 12.19 hrs, Volume= 0.050 af, Depth= 1.39" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs NOAA 24-hr D 2-Year-2050 Rainfall=4.09", P2=4.09" Area (sf) CN Description 18,843 70 Woods, Good, HSG C 18,843 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.8 100 0.0370 0.25 Sheet Flow, Grass: Short n= 0.150 P2= 4.09" 4.1 244 0.0400 1.00 Shallow Concentrated Flow, Woodland Kv= 5.0 fps 10.9 344 Total Subcatchment 1S: Existing Conditions Study Area Hydrograph 0.6 0.57 cfs Runoff 0.55 NOAA 24-hr D 0.5 2-Year-2050 Rainfall=4.09" 0.45 P2=4.09" 0.4 Runoff Area=18,843 sf Flow (cfs) 0.35

0.4 Runoff Area=18,843 sf Flow (cfs) 0.35 Runoff Volume=0.050 af 0.3 Runoff Depth=1.39" 0.25 Flow Length=344' 0.2 Tc=10.9 min 0.15 CN=70 0.1 0.05 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours)

29906 15 Ridgeway West Orange Final NOAA 24-hr D 10-Year-2050 Rainfall=6.37", P2=4.09" Prepared by Ensurplan Inc Printed 4/20/2026 HydroCAD® 10.20-8a s/n 11646 © 2025 HydroCAD Software Solutions LLC Page 22 Summary for Subcatchment 1S: Existing Conditions Study Area Runoff = 1.31 cfs @ 12.19 hrs, Volume= 0.112 af, Depth= 3.10" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs NOAA 24-hr D 10-Year-2050 Rainfall=6.37", P2=4.09" Area (sf) CN Description 18,843 70 Woods, Good, HSG C 18,843 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.8 100 0.0370 0.25 Sheet Flow, Grass: Short n= 0.150 P2= 4.09" 4.1 244 0.0400 1.00 Shallow Concentrated Flow, Woodland Kv= 5.0 fps 10.9 344 Total Subcatchment 1S: Existing Conditions Study Area Hydrograph 1.31 cfs Runoff NOAA 24-hr D 10-Year-2050 Rainfall=6.37" 1 P2=4.09" Runoff Area=18,843 sf Flow (cfs) Runoff Volume=0.112 af

Runoff Volume=0.112 af Runoff Depth=3.10" Flow Length=344' Tc=10.9 min CN=70 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours)

29906 15 Ridgeway West Orange Fin NOAA 24-hr D 100-Year-2050 Rainfall=11.52", P2=4.09" Prepared by Ensurplan Inc Printed 4/20/2026 HydroCAD® 10.20-8a s/n 11646 © 2025 HydroCAD Software Solutions LLC Page 23 Summary for Subcatchment 1S: Existing Conditions Study Area Runoff = 3.17 cfs @ 12.18 hrs, Volume= 0.274 af, Depth= 7.61" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs NOAA 24-hr D 100-Year-2050 Rainfall=11.52", P2=4.09" Area (sf) CN Description 18,843 70 Woods, Good, HSG C 18,843 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.8 100 0.0370 0.25 Sheet Flow, Grass: Short n= 0.150 P2= 4.09" 4.1 244 0.0400 1.00 Shallow Concentrated Flow, Woodland Kv= 5.0 fps 10.9 344 Total Subcatchment 1S: Existing Conditions Study Area Hydrograph 3.17 cfs Runoff 3 NOAA 24-hr D 100-Year-2050 Rainfall=11.52" P2=4.09" Runoff Area=18,843 sf 2 Runoff Volume=0.274 af Flow (cfs)

2 Runoff Volume=0.274 af Flow (cfs) Runoff Depth=7.61" Flow Length=344' Tc=10.9 min 1 CN=70 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours)

​ENSURPLAN, INC.​ ​ ww.Ensurplan.​​net​ w ​ ivil Engineers & Land Surveyors C Ph: (732) 469-0400​ ​Certificate of Authorization 24GA27997700​ ​STORMWATER DRAINAGE REPORT​ ​04/13/26​ ​Minor Subdivision 15 Ridgeway Ave West Orange, NJ​ ​Proposed Conditions Information and Hydrographs​ ​24​ ​Mailing Address: Post Office Box 4304, Warren, NJ 07059​

29906 15 Ridgeway West Orange Final NOAA 24-hr D 2-Year-2020 Rainfall=3.47", P2=3.47" Prepared by Ensurplan Inc Printed 4/20/2026 HydroCAD® 10.20-8a s/n 11646 © 2025 HydroCAD Software Solutions LLC Page 25 Summary for Subcatchment 13S: Bypass Infiltration, Overland to Study Point at Inlet Runoff = 0.03 cfs @ 12.13 hrs, Volume= 0.002 af, Depth= 3.24" Routed to Reach 12R : Study Point At Inlet Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs NOAA 24-hr D 2-Year-2020 Rainfall=3.47", P2=3.47" Area (sf) CN Description * 384 98 Misc Impervious To Rear Property 384 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.3 65 0.0600 0.17 Sheet Flow, Grass: Dense n= 0.240 P2= 3.47" Subcatchment 13S: Bypass Infiltration, Overland to Study Point at Inlet Hydrograph 0.032 0.03 0.03 cfs Runoff 0.028 0.026 NOAA 24-hr D 0.024 2-Year-2020 Rainfall=3.47" 0.022 P2=3.47" 0.02 Runoff Area=384 sf Flow (cfs) 0.018 Runoff Volume=0.002 af 0.016

a=384 sf Flow (cfs) 0.018 Runoff Volume=0.002 af 0.016 0.014 Runoff Depth=3.24" 0.012 Flow Length=65' 0.01 Slope=0.0600 '/' 0.008 Tc=6.3 min 0.006 0.004 CN=98 0.002 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours)

29906 15 Ridgeway West Orange Final NOAA 24-hr D 10-Year-2020 Rainfall=5.38", P2=3.47" Prepared by Ensurplan Inc Printed 4/20/2026 HydroCAD® 10.20-8a s/n 11646 © 2025 HydroCAD Software Solutions LLC Page 26 Summary for Subcatchment 13S: Bypass Infiltration, Overland to Study Point at Inlet Runoff = 0.04 cfs @ 12.13 hrs, Volume= 0.004 af, Depth= 5.14" Routed to Reach 12R : Study Point At Inlet Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs NOAA 24-hr D 10-Year-2020 Rainfall=5.38", P2=3.47" Area (sf) CN Description * 384 98 Misc Impervious To Rear Property 384 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.3 65 0.0600 0.17 Sheet Flow, Grass: Dense n= 0.240 P2= 3.47" Subcatchment 13S: Bypass Infiltration, Overland to Study Point at Inlet Hydrograph 0.05 0.048 0.046 0.04 cfs Runoff 0.044 0.042 NOAA 24-hr D 0.04 0.038 10-Year-2020 Rainfall=5.38" 0.036 0.034 P2=3.47" 0.032 0.03 Runoff Area=384 sf Runoff Volume=0.004 af Flow (cfs)