Stormwater Management Report 03302026

24-223 DRAINAGE DESIGN-PROPOSED-2026-03-30 NOAA 24-hr D 10-Year-2020 Rainfall=5.38", P2=3.47" Prepared by Jarmel Kizel Architects & Engnrs Printed 3/30/2026 HydroCAD® 10.20-6a s/n 12607 © 2024 HydroCAD Software Solutions LLC Page 29 Summary for Subcatchment P1-P: P1 PERVIOUS Runoff = 0.19 cfs @ 12.07 hrs, Volume= 1,197 cf, Depth= 2.67" Routed to Link 11L : Proposed Disturbed Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.50 hrs NOAA 24-hr D 10-Year-2020 Rainfall=5.38", P2=3.47" Area (sf) CN Description 5,380 74 >75% Grass cover, Good, HSG C 5,380 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.3 83 0.0660 0.19 Sheet Flow, Grass: Dense n= 0.240 P2= 3.47" 0.1 36 0.0280 9.54 11.71 Pipe Channel, Yard Inlet 15.0" Round Area= 1.2 sf Perim= 3.9' r= 0.31' n= 0.012 0.2 325 0.0450 31.77 898.40 Pipe Channel, 72" Culvert 72.0" Round Area= 28.3 sf Perim= 18.8' r= 1.50' n= 0.013 7.6 444 Total

24-223 DRAINAGE DESIGN-PROPOSED-2026-03-30 NOAA 24-hr D 10-Year-2020 Rainfall=5.38", P2=3.47" Prepared by Jarmel Kizel Architects & Engnrs Printed 3/30/2026 HydroCAD® 10.20-6a s/n 12607 © 2024 HydroCAD Software Solutions LLC Page 30 Subcatchment P1-P: P1 PERVIOUS Hydrograph Runoff 0.2 0.19 cfs 0.19 0.18 NOAA 24-hr D 0.17 10-Year-2020 Rainfall=5.38" 0.16 0.15 P2=3.47" 0.14 0.13 Runoff Area=5,380 sf 0.12 Runoff Volume=1,197 cf Flow (cfs) 0.11 0.1 Runoff Depth=2.67" 0.09 Flow Length=444' 0.08 0.07 Tc=7.6 min 0.06 0.05 CN=74 0.04 0.03 0.02 0.01 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours)

24-223 DRAINAGE DESIGN-PROPOSED-2026-03-30 NOAA 24-hr D 10-Year-2020 Rainfall=5.38", P2=3.47" Prepared by Jarmel Kizel Architects & Engnrs Printed 3/30/2026 HydroCAD® 10.20-6a s/n 12607 © 2024 HydroCAD Software Solutions LLC Page 31 Summary for Subcatchment P2: P2 Pervious-w-offsite-Undisturbed Runoff = 1.22 cfs @ 12.27 hrs, Volume= 9,574 cf, Depth= 2.49" Routed to Link P-DP 1 : PROP DP 1 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.50 hrs NOAA 24-hr D 10-Year-2020 Rainfall=5.38", P2=3.47" Area (sf) CN Description * 708 98 Roof-offsite * 1,220 98 Impervious-offsite 2,721 71 Meadow, non-grazed, HSG C * 32,255 70 wooded 1,240 74 >75% Grass cover, Good, HSG C * 7,915 72 Woods/grass comb., Good, HSG C 46,059 72 Weighted Average 44,131 95.81% Pervious Area 1,928 4.19% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 11.3 100 0.0900 0.15 Sheet Flow, sheet flow Woods: Light underbrush n= 0.400 P2= 3.47" 0.6 123 0.5000 3.54 Shallow Concentrated Flow, SC Woodland Kv= 5.0 fps 1.7 445 0.0470 4.40 Shallow Concentrated Flow, Parking lot Paved Kv= 20.3 fps 13.6 668 Total

24-223 DRAINAGE DESIGN-PROPOSED-2026-03-30 NOAA 24-hr D 10-Year-2020 Rainfall=5.38", P2=3.47" Prepared by Jarmel Kizel Architects & Engnrs Printed 3/30/2026 HydroCAD® 10.20-6a s/n 12607 © 2024 HydroCAD Software Solutions LLC Page 32 Subcatchment P2: P2 Pervious-w-offsite-Undisturbed Hydrograph Runoff 1.22 cfs NOAA 24-hr D 10-Year-2020 Rainfall=5.38" 1 P2=3.47" Runoff Area=46,059 sf Runoff Volume=9,574 cf Flow (cfs) Runoff Depth=2.49" Flow Length=668' Tc=13.6 min CN=72 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours)

24-223 DRAINAGE DESIGN-PROPOSED-2026-03-30 NOAA 24-hr D 10-Year-2020 Rainfall=5.38", P2=3.47" Prepared by Jarmel Kizel Architects & Engnrs Printed 3/30/2026 HydroCAD® 10.20-6a s/n 12607 © 2024 HydroCAD Software Solutions LLC Page 33 Summary for Subcatchment P3A-IMP: P3A IMPERVIOUS Runoff = 0.27 cfs @ 12.01 hrs, Volume= 1,731 cf, Depth= 5.14" Routed to Link P-DP 2 : PROP DP 2 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.50 hrs NOAA 24-hr D 10-Year-2020 Rainfall=5.38", P2=3.47" Area (sf) CN Description * 4,040 98 DRIVE/SIDEWALK 4,040 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 0.8 100 0.0500 2.07 Sheet Flow, Pavement Smooth surfaces n= 0.011 P2= 3.47" 1.2 335 0.0500 4.54 Shallow Concentrated Flow, shadow concentrate Paved Kv= 20.3 fps 2.0 435 Total

24-223 DRAINAGE DESIGN-PROPOSED-2026-03-30 NOAA 24-hr D 10-Year-2020 Rainfall=5.38", P2=3.47" Prepared by Jarmel Kizel Architects & Engnrs Printed 3/30/2026 HydroCAD® 10.20-6a s/n 12607 © 2024 HydroCAD Software Solutions LLC Page 34 Subcatchment P3A-IMP: P3A IMPERVIOUS Hydrograph Runoff 0.28 0.27 cfs 0.26 NOAA 24-hr D 0.24 10-Year-2020 Rainfall=5.38" 0.22 P2=3.47" 0.2 Runoff Area=4,040 sf 0.18 Runoff Volume=1,731 cf Flow (cfs) 0.16 0.14 Runoff Depth=5.14" 0.12 Flow Length=435' 0.1 Slope=0.0500 '/' 0.08 Tc=2.0 min 0.06 CN=98 0.04 0.02 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours)

24-223 DRAINAGE DESIGN-PROPOSED-2026-03-30 NOAA 24-hr D 10-Year-2020 Rainfall=5.38", P2=3.47" Prepared by Jarmel Kizel Architects & Engnrs Printed 3/30/2026 HydroCAD® 10.20-6a s/n 12607 © 2024 HydroCAD Software Solutions LLC Page 35 Summary for Subcatchment P3A-P: P3A PERVIOUS Runoff = 0.21 cfs @ 12.06 hrs, Volume= 1,319 cf, Depth= 2.67" Routed to Link P-DP 2 : PROP DP 2 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.50 hrs NOAA 24-hr D 10-Year-2020 Rainfall=5.38", P2=3.47" Area (sf) CN Description 5,928 74 >75% Grass cover, Good, HSG C 5,928 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.1 100 0.0600 0.27 Sheet Flow, sheet flow Grass: Short n= 0.150 P2= 3.47" 0.1 29 0.0550 3.78 Shallow Concentrated Flow, Lawn Unpaved Kv= 16.1 fps 6.2 129 Total

24-223 DRAINAGE DESIGN-PROPOSED-2026-03-30 NOAA 24-hr D 10-Year-2020 Rainfall=5.38", P2=3.47" Prepared by Jarmel Kizel Architects & Engnrs Printed 3/30/2026 HydroCAD® 10.20-6a s/n 12607 © 2024 HydroCAD Software Solutions LLC Page 36 Subcatchment P3A-P: P3A PERVIOUS Hydrograph Runoff 0.23 0.22 0.21 cfs 0.21 NOAA 24-hr D 0.2 0.19 10-Year-2020 Rainfall=5.38" 0.18 0.17 P2=3.47" 0.16 0.15 Runoff Area=5,928 sf 0.14 Runoff Volume=1,319 cf Flow (cfs) 0.13 0.12 Runoff Depth=2.67" 0.11 0.1 Flow Length=129' 0.09 0.08 Tc=6.2 min 0.07 0.06 CN=74 0.05 0.04 0.03 0.02 0.01 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours)

24-223 DRAINAGE DESIGN-PROPOSED-2026-03-30 NOAA 24-hr D 10-Year-2020 Rainfall=5.38", P2=3.47" Prepared by Jarmel Kizel Architects & Engnrs Printed 3/30/2026 HydroCAD® 10.20-6a s/n 12607 © 2024 HydroCAD Software Solutions LLC Page 37 Summary for Subcatchment P3B-IMP: P3B IMPERVIOUS Runoff = 0.06 cfs @ 12.00 hrs, Volume= 420 cf, Depth= 5.14" Routed to Link P-DP 2 : PROP DP 2 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.50 hrs NOAA 24-hr D 10-Year-2020 Rainfall=5.38", P2=3.47" Area (sf) CN Description * 980 98 SIDEWALK AREA 980 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 0.6 100 0.0900 2.61 Sheet Flow, sidewalk Smooth surfaces n= 0.011 P2= 3.47" 0.5 88 0.0220 3.01 Shallow Concentrated Flow, shadow concentrate Paved Kv= 20.3 fps 1.1 188 Total

24-223 DRAINAGE DESIGN-PROPOSED-2026-03-30 NOAA 24-hr D 10-Year-2020 Rainfall=5.38", P2=3.47" Prepared by Jarmel Kizel Architects & Engnrs Printed 3/30/2026 HydroCAD® 10.20-6a s/n 12607 © 2024 HydroCAD Software Solutions LLC Page 38 Subcatchment P3B-IMP: P3B IMPERVIOUS Hydrograph 0.07 Runoff 0.06 cfs 0.065 NOAA 24-hr D 0.06 10-Year-2020 Rainfall=5.38" 0.055 P2=3.47" 0.05 0.045 Runoff Area=980 sf Runoff Volume=420 cf Flow (cfs) 0.04 0.035 Runoff Depth=5.14" 0.03 Flow Length=188' 0.025 Tc=1.1 min 0.02 CN=98 0.015 0.01 0.005 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours)