Stormwater Management Report 03302026

24-223 DRAINAGE DESIGN-PROPOSED-2026-03-30 NOAA 24-hr D 100-Year-2020 Rainfall=9.18", 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 49 Summary for Subcatchment P1-I: P1 IMPERVIOUS PARKING Runoff = 2.73 cfs @ 12.01 hrs, Volume= 18,099 cf, Depth= 8.94" 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 100-Year-2020 Rainfall=9.18", P2=3.47" Area (sf) CN Description * 24,295 98 Uncovered Paved parking, HSG C 24,295 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 1.5 100 0.0150 1.12 Sheet Flow, sheet flow Parking area n= 0.013 P2= 3.47" 0.9 127 0.0150 2.49 Shallow Concentrated Flow, parking area Paved Kv= 20.3 fps 0.3 198 0.0449 12.08 14.83 Pipe Channel, Pipe flow 15.0" Round Area= 1.2 sf Perim= 3.9' r= 0.31' n= 0.012 2.7 425 Total

24-223 DRAINAGE DESIGN-PROPOSED-2026-03-30 NOAA 24-hr D 100-Year-2020 Rainfall=9.18", 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 50 Subcatchment P1-I: P1 IMPERVIOUS PARKING Hydrograph 3 Runoff 2.73 cfs NOAA 24-hr D 100-Year-2020 Rainfall=9.18" P2=3.47" 2 Runoff Area=24,295 sf Runoff Volume=18,099 cf Flow (cfs) Runoff Depth=8.94" Flow Length=425' Tc=2.7 min 1 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 100-Year-2020 Rainfall=9.18", 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 51 Summary for Subcatchment P1-P: P1 PERVIOUS Runoff = 0.43 cfs @ 12.06 hrs, Volume= 2,687 cf, Depth= 5.99" 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 100-Year-2020 Rainfall=9.18", 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 100-Year-2020 Rainfall=9.18", 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 52 Subcatchment P1-P: P1 PERVIOUS Hydrograph 0.46 Runoff 0.44 0.43 cfs 0.42 NOAA 24-hr D 0.4 0.38 100-Year-2020 Rainfall=9.18" 0.36 0.34 P2=3.47" 0.32 Runoff Area=5,380 sf 0.3 0.28 Runoff Volume=2,687 cf Flow (cfs) 0.26 0.24 Runoff Depth=5.99" 0.22 Flow Length=444' 0.2 0.18 Tc=7.6 min 0.16 0.14 CN=74 0.12 0.1 0.08 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 100-Year-2020 Rainfall=9.18", 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 53 Summary for Subcatchment P2: P2 Pervious-w-offsite-Undisturbed Runoff = 2.90 cfs @ 12.20 hrs, Volume= 22,046 cf, Depth= 5.74" 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 100-Year-2020 Rainfall=9.18", 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 100-Year-2020 Rainfall=9.18", 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 54 Subcatchment P2: P2 Pervious-w-offsite-Undisturbed Hydrograph Runoff 3 2.90 cfs NOAA 24-hr D 100-Year-2020 Rainfall=9.18" P2=3.47" Runoff Area=46,059 sf 2 Runoff Volume=22,046 cf Flow (cfs) Runoff Depth=5.74" Flow Length=668' Tc=13.6 min 1 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 100-Year-2020 Rainfall=9.18", 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 55 Summary for Subcatchment P3A-IMP: P3A IMPERVIOUS Runoff = 0.45 cfs @ 12.01 hrs, Volume= 3,010 cf, Depth= 8.94" 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 100-Year-2020 Rainfall=9.18", 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 100-Year-2020 Rainfall=9.18", 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 56 Subcatchment P3A-IMP: P3A IMPERVIOUS Hydrograph 0.5 Runoff 0.48 0.45 cfs 0.46 0.44 NOAA 24-hr D 0.42 0.4 100-Year-2020 Rainfall=9.18" 0.38 P2=3.47" 0.36 0.34 Runoff Area=4,040 sf 0.32 0.3 Runoff Volume=3,010 cf Flow (cfs) 0.28 0.26 Runoff Depth=8.94" 0.24 0.22 Flow Length=435' 0.2 Slope=0.0500 '/' 0.18 0.16 Tc=2.0 min 0.14 0.12 CN=98 0.1 0.08 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

0.08 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 100-Year-2020 Rainfall=9.18", 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 57 Summary for Subcatchment P3A-P: P3A PERVIOUS Runoff = 0.48 cfs @ 12.04 hrs, Volume= 2,961 cf, Depth= 5.99" 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 100-Year-2020 Rainfall=9.18", 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