Stormwater Management Report 03302026

24-223 DRAINAGE DESIGN-PROPOSED-2026-03-30 NOAA 24-hr D 10-Year-2050 Rainfall=6.37", P2=4.09" Prepared by Jarmel Kizel Architects & Engnrs Printed 3/30/2026 HydroCAD® 10.20-6a s/n 12607 © 2024 HydroCAD Software Solutions LLC Page 94 Subcatchment P1-I: P1 IMPERVIOUS PARKING Hydrograph Runoff 2 1.89 cfs NOAA 24-hr D 10-Year-2050 Rainfall=6.37" P2=4.09" Runoff Area=24,295 sf Runoff Volume=12,414 cf Flow (cfs) 1 Runoff Depth=6.13" Flow Length=425' Tc=2.6 min CN=98 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-2050 Rainfall=6.37", P2=4.09" Prepared by Jarmel Kizel Architects & Engnrs Printed 3/30/2026 HydroCAD® 10.20-6a s/n 12607 © 2024 HydroCAD Software Solutions LLC Page 95 Summary for Subcatchment P1-P: P1 PERVIOUS Runoff = 0.25 cfs @ 12.06 hrs, Volume= 1,568 cf, Depth= 3.50" 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-2050 Rainfall=6.37", P2=4.09" 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) 6.7 83 0.0660 0.21 Sheet Flow, Grass: Dense n= 0.240 P2= 4.09" 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 7.0 444 Total

24-223 DRAINAGE DESIGN-PROPOSED-2026-03-30 NOAA 24-hr D 10-Year-2050 Rainfall=6.37", P2=4.09" Prepared by Jarmel Kizel Architects & Engnrs Printed 3/30/2026 HydroCAD® 10.20-6a s/n 12607 © 2024 HydroCAD Software Solutions LLC Page 96 Subcatchment P1-P: P1 PERVIOUS Hydrograph 0.28 Runoff 0.26 0.25 cfs 0.24 NOAA 24-hr D 0.22 10-Year-2050 Rainfall=6.37" 0.2 P2=4.09" 0.18 Runoff Area=5,380 sf 0.16 Runoff Volume=1,568 cf Flow (cfs) 0.14 Runoff Depth=3.50" 0.12 Flow Length=444' 0.1 Tc=7.0 min 0.08 CN=74 0.06 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-2050 Rainfall=6.37", P2=4.09" Prepared by Jarmel Kizel Architects & Engnrs Printed 3/30/2026 HydroCAD® 10.20-6a s/n 12607 © 2024 HydroCAD Software Solutions LLC Page 97 Summary for Subcatchment P2: P2 Pervious-w-offsite-Undisturbed Runoff = 1.68 cfs @ 12.19 hrs, Volume= 12,660 cf, Depth= 3.30" 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-2050 Rainfall=6.37", P2=4.09" 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) 10.4 100 0.0900 0.16 Sheet Flow, sheet flow Woods: Light underbrush n= 0.400 P2= 4.09" 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 12.7 668 Total

24-223 DRAINAGE DESIGN-PROPOSED-2026-03-30 NOAA 24-hr D 10-Year-2050 Rainfall=6.37", P2=4.09" Prepared by Jarmel Kizel Architects & Engnrs Printed 3/30/2026 HydroCAD® 10.20-6a s/n 12607 © 2024 HydroCAD Software Solutions LLC Page 98 Subcatchment P2: P2 Pervious-w-offsite-Undisturbed Hydrograph Runoff 1.68 cfs NOAA 24-hr D 10-Year-2050 Rainfall=6.37" P2=4.09" Runoff Area=46,059 sf Runoff Volume=12,660 cf Flow (cfs) 1 Runoff Depth=3.30" Flow Length=668' Tc=12.7 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-2050 Rainfall=6.37", P2=4.09" Prepared by Jarmel Kizel Architects & Engnrs Printed 3/30/2026 HydroCAD® 10.20-6a s/n 12607 © 2024 HydroCAD Software Solutions LLC Page 99 Summary for Subcatchment P3A-IMP: P3A IMPERVIOUS Runoff = 0.31 cfs @ 12.01 hrs, Volume= 2,064 cf, Depth= 6.13" 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-2050 Rainfall=6.37", P2=4.09" 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) 0.7 100 0.0500 2.24 Sheet Flow, Pavement Smooth surfaces n= 0.011 P2= 4.09" 1.2 335 0.0500 4.54 Shallow Concentrated Flow, shadow concentrate Paved Kv= 20.3 fps 1.9 435 Total

24-223 DRAINAGE DESIGN-PROPOSED-2026-03-30 NOAA 24-hr D 10-Year-2050 Rainfall=6.37", P2=4.09" Prepared by Jarmel Kizel Architects & Engnrs Printed 3/30/2026 HydroCAD® 10.20-6a s/n 12607 © 2024 HydroCAD Software Solutions LLC Page 100 Subcatchment P3A-IMP: P3A IMPERVIOUS Hydrograph 0.34 Runoff 0.31 cfs 0.32 0.3 NOAA 24-hr D 0.28 10-Year-2050 Rainfall=6.37" 0.26 P2=4.09" 0.24 0.22 Runoff Area=4,040 sf 0.2 Runoff Volume=2,064 cf Flow (cfs) 0.18 Runoff Depth=6.13" 0.16 0.14 Flow Length=435' 0.12 Slope=0.0500 '/' 0.1 Tc=1.9 min 0.08 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

2 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-2050 Rainfall=6.37", P2=4.09" Prepared by Jarmel Kizel Architects & Engnrs Printed 3/30/2026 HydroCAD® 10.20-6a s/n 12607 © 2024 HydroCAD Software Solutions LLC Page 101 Summary for Subcatchment P3A-P: P3A PERVIOUS Runoff = 0.28 cfs @ 12.05 hrs, Volume= 1,728 cf, Depth= 3.50" 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-2050 Rainfall=6.37", P2=4.09" 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) 5.6 100 0.0600 0.30 Sheet Flow, sheet flow Grass: Short n= 0.150 P2= 4.09" 0.1 29 0.0550 3.78 Shallow Concentrated Flow, Lawn Unpaved Kv= 16.1 fps 5.7 129 Total

24-223 DRAINAGE DESIGN-PROPOSED-2026-03-30 NOAA 24-hr D 10-Year-2050 Rainfall=6.37", P2=4.09" Prepared by Jarmel Kizel Architects & Engnrs Printed 3/30/2026 HydroCAD® 10.20-6a s/n 12607 © 2024 HydroCAD Software Solutions LLC Page 102 Subcatchment P3A-P: P3A PERVIOUS Hydrograph Runoff 0.3 0.28 cfs 0.28 NOAA 24-hr D 0.26 10-Year-2050 Rainfall=6.37" 0.24 P2=4.09" 0.22 0.2 Runoff Area=5,928 sf Runoff Volume=1,728 cf Flow (cfs) 0.18 0.16 Runoff Depth=3.50" 0.14 Flow Length=129' 0.12 0.1 Tc=5.7 min 0.08 CN=74 0.06 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)