Drainage Report and Supplement 82625

2025-08-13_Stormwater Calculations NOAA 24-hr D 100-Year-2050 Rainfall=11.52", P2=4.09" Prepared by Stonefield Engineering & Design HydroCAD® 10.20-5c s/n 10626 © 2023 HydroCAD Software Solutions LLC Printed 8/13/2025 Page 50 Summary for Subcatchment E-2: Existing Drainage to Nicholas Avenue Runoff = 36.07 cfs @ 12.10 hrs, Volume= Routed to nonexistent node POI-2 110,742 cf, Depth= 9.24" Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.01 hrs NOAA 24-hr D 100-Year-2050 Rainfall=11.52", P2=4.09" * * * Area (sf) 35,530 58,832 4,420 27,460 17,504 143,746 108,216 35,530 Tc (min) 0.0 Length (feet) 4 0.0 3 0.2 29 0.3 45 1.1 107 0.7 77 0.1 27 0.1 24 0.1 17 0.0 16 0.0 7 0.2 52 2.8 408 CN 98 74 70 74 96 82 77 98 Description Impervious Surface >75% Grass cover, Good, HSG C Woods, Good, HSG C Sand Riding Area Gravel surface Weighted Average 75.28% Pervious Area 24.72% Impervious Area Slope Velocity Capacity Description (ft/ft) (ft/sec) (cfs) 0.2410 2.21 Sheet Flow, D1-D2 Smooth surfaces n= 0.011 P2= 4.09" 0.2930 10.99 Shallow Concentrated Flow, D2-D3 Paved Kv= 20.3 fps 0.0340 2.97 Shallow Concentrated Flow, D3-D4 Unpaved Kv= 16.1 fps 0.0220 2.39 Shallow Concentrated Flow, D4-D5 Unpaved Kv= 16.1 fps 0.0100 1.61 Shallow Concentrated Flow, D5-D6 Unpaved Kv= 16.1 fps 0.0130 1.84 Shallow Concentrated Flow, D6-D7 Unpaved Kv= 16.1 fps 0.0370 3.10 Shallow Concentrated Flow, D7-D8 Unpaved Kv= 16.1 fps 0.0420 3.30 Shallow Concentrated Flow, D8-D9 Unpaved Kv= 16.1 fps 0.1170 5.51 Shallow Concentrated Flow, D9-D10 Unpaved Kv= 16.1 fps 0.1220 5.62 Shallow Concentrated Flow, D10-D11 Unpaved Kv= 16.1 fps 0.2860 8.61 Shallow Concentrated Flow, D11-D12 Unpaved Kv= 16.1 fps 0.0580 3.88 Shallow Concentrated Flow, D12-D13 Unpaved Kv= 16.1 fps Total

2025-08-13_Stormwater Calculations NOAA 24-hr D 100-Year-2050 Rainfall=11.52", P2=4.09" Prepared by Stonefield Engineering & Design HydroCAD® 10.20-5c s/n 10626 © 2023 HydroCAD Software Solutions LLC Printed 8/13/2025 Page 51 Subcatchment E-2: Existing Drainage to Nicholas Avenue Hydrograph 40 Runoff 38 36.07 cfs 36 34 32 30 Flow (cfs) 28 26 24 22 20 18 16 14 12 NOAA 24-hr D 100-Year-2050 Rainfall=11.52" P2=4.09" Runoff Area=143,746 sf Runoff Volume=110,742 cf Runoff Depth=9.24" Flow Length=408' Tc=2.8 min CN=77/98 10 8 6 4 2 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 50 52 54 56 58 60 62 64 66 68 70 72 Time (hours)

2025-08-13_Stormwater Calculations NOAA 24-hr D 100-Year-2050 Rainfall=11.52", P2=4.09" Prepared by Stonefield Engineering & Design HydroCAD® 10.20-5c s/n 10626 © 2023 HydroCAD Software Solutions LLC Printed 8/13/2025 Page 52 Summary for Subcatchment P-1: Proposed Drainage to Woodland Avenue Runoff = 8.08 cfs @ 12.10 hrs, Volume= Routed to nonexistent node P0I-1 24,971 cf, Depth= 9.29" Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.01 hrs NOAA 24-hr D 100-Year-2050 Rainfall=11.52", P2=4.09" * * Area (sf) 11,698 9,040 11,500 32,238 20,540 11,698 Tc (min) 1.7 Length (feet) 23 0.1 9 0.2 41 0.2 43 0.2 36 0.1 26 2.5 178 CN 98 74 74 83 74 98 Description Impervious Surface >75% Grass cover, Good, HSG C Sand Riding Area Weighted Average 63.71% Pervious Area 36.29% Impervious Area Slope Velocity Capacity Description (ft/ft) (ft/sec) (cfs) 0.0652 0.23 Sheet Flow, B1-B2 Grass: Short n= 0.150 P2= 4.09" 0.0110 2.13 Shallow Concentrated Flow, B2-B3 Paved Kv= 20.3 fps 0.0220 3.01 Shallow Concentrated Flow, B3-B4 Paved Kv= 20.3 fps 0.0470 4.40 Shallow Concentrated Flow, B4-B5 Paved Kv= 20.3 fps 0.0280 3.40 Shallow Concentrated Flow, B5-B6 Paved Kv= 20.3 fps 0.0310 3.57 Shallow Concentrated Flow, B6-B7 Paved Kv= 20.3 fps Total

2025-08-13_Stormwater Calculations NOAA 24-hr D 100-Year-2050 Rainfall=11.52", P2=4.09" Prepared by Stonefield Engineering & Design HydroCAD® 10.20-5c s/n 10626 © 2023 HydroCAD Software Solutions LLC Printed 8/13/2025 Page 53 Subcatchment P-1: Proposed Drainage to Woodland Avenue Hydrograph 9 Runoff 8.08 cfs 8 7 Flow (cfs) 6 5 4 3 NOAA 24-hr D 100-Year-2050 Rainfall=11.52" P2=4.09" Runoff Area=32,238 sf Runoff Volume=24,971 cf Runoff Depth=9.29" Flow Length=178' Tc=2.5 min CN=74/98 2 1 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 50 52 54 56 58 60 62 64 66 68 70 72 Time (hours)

2025-08-13_Stormwater Calculations NOAA 24-hr D 100-Year-2050 Rainfall=11.52", P2=4.09" Prepared by Stonefield Engineering & Design HydroCAD® 10.20-5c s/n 10626 © 2023 HydroCAD Software Solutions LLC Printed 8/13/2025 Page 54 Summary for Subcatchment P-2: Proposed Drainage to Nicholas Avenue Runoff = 36.01 cfs @ 12.10 hrs, Volume= Routed to nonexistent node P0I-2 110,505 cf, Depth= 9.23" Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.01 hrs NOAA 24-hr D 100-Year-2050 Rainfall=11.52", P2=4.09" * * * Area (sf) 34,911 69,978 22,575 16,145 143,609 108,698 34,911 Tc (min) 0.0 Length (feet) 4 0.0 3 0.2 29 0.3 45 1.1 107 0.7 77 0.1 27 0.1 24 0.1 17 0.0 16 0.0 7 0.2 52 2.8 408 CN 98 74 74 96 82 77 98 Description Impervious Surface >75% Grass cover, Good, HSG C Sand Riding Area Gravel surface Weighted Average 75.69% Pervious Area 24.31% Impervious Area Slope Velocity Capacity Description (ft/ft) (ft/sec) (cfs) 0.2410 2.21 Sheet Flow, D1-D2 Smooth surfaces n= 0.011 P2= 4.09" 0.2930 10.99 Shallow Concentrated Flow, D2-D3 Paved Kv= 20.3 fps 0.0340 2.97 Shallow Concentrated Flow, D3-D4 Unpaved Kv= 16.1 fps 0.0220 2.39 Shallow Concentrated Flow, D4-D5 Unpaved Kv= 16.1 fps 0.0100 1.61 Shallow Concentrated Flow, D5-D6 Unpaved Kv= 16.1 fps 0.0130 1.84 Shallow Concentrated Flow, D6-D7 Unpaved Kv= 16.1 fps 0.0370 3.10 Shallow Concentrated Flow, D7-D8 Unpaved Kv= 16.1 fps 0.0420 3.30 Shallow Concentrated Flow, D8-D9 Unpaved Kv= 16.1 fps 0.1170 5.51 Shallow Concentrated Flow, D9-D10 Unpaved Kv= 16.1 fps 0.1220 5.62 Shallow Concentrated Flow, D10-D11 Unpaved Kv= 16.1 fps 0.2860 8.61 Shallow Concentrated Flow, D11-D12 Unpaved Kv= 16.1 fps 0.0580 3.88 Shallow Concentrated Flow, D12-D13 Unpaved Kv= 16.1 fps Total

2025-08-13_Stormwater Calculations NOAA 24-hr D 100-Year-2050 Rainfall=11.52", P2=4.09" Prepared by Stonefield Engineering & Design HydroCAD® 10.20-5c s/n 10626 © 2023 HydroCAD Software Solutions LLC Printed 8/13/2025 Page 55 Subcatchment P-2: Proposed Drainage to Nicholas Avenue Hydrograph 40 Runoff 38 36.01 cfs 36 34 32 30 28 Flow (cfs) 26 24 22 20 18 16 14 12 10 NOAA 24-hr D 100-Year-2050 Rainfall=11.52" P2=4.09" Runoff Area=143,609 sf Runoff Volume=110,505 cf Runoff Depth=9.23" Flow Length=408' Tc=2.8 min CN=77/98 8 6 4 2 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 50 52 54 56 58 60 62 64 66 68 70 72 Time (hours)

NOAA 24-hr D 2-Year-2020 Rainfall=3.47", P2=3.47" Printed 8/13/2025 Prepared by Stonefield Engineering & Design 2025-08-13_Stormwater Calculations HydroCAD® 10.20-5c s/n 10626 © 2023 HydroCAD Software Solutions LLC Primary Comparison 2 1.84 cfs Primary (cfs) 1.73 cfs 1 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 50 52 54 56 58 60 62 64 66 68 70 72 Time (hours) Subcat E-1 Subcat P-1

NOAA 24-hr D 2-Year-2020 Rainfall=3.47", P2=3.47" Printed 8/13/2025 Prepared by Stonefield Engineering & Design 2025-08-13_Stormwater Calculations HydroCAD® 10.20-5c s/n 10626 © 2023 HydroCAD Software Solutions LLC Primary Comparison Time Subcat E-1 Subcat P-1 (hours) (cfs) (cfs) 0.00 0.00 0.00 0.05 0.00 0.00 0.10 0.00 0.00 0.15 0.00 0.00 0.20 0.00 0.00 0.25 0.00 0.00 0.30 0.00 0.00 0.35 0.00 0.00 0.40 0.00 0.00 0.45 0.00 0.00 0.50 0.00 0.00 0.55 0.00 0.00 0.60 0.00 0.00 0.65 0.00 0.00 0.70 0.00 0.00 0.75 0.00 0.00 0.80 0.00 0.00 0.85 0.00 0.00 0.90 0.00 0.00 0.95 0.00 0.00 1.00 0.00 0.00 1.05 0.00 0.00 1.10 0.00 0.00 1.15 0.00 0.00 1.20 0.00 0.00 1.25 0.00 0.00 1.30 0.00 0.00 1.35 0.00 0.00 1.40 0.00 0.00 1.45 0.00 0.00 1.50 0.00 0.00 1.55 0.00 0.00 1.60 0.00 0.00 1.65 0.00 0.00 1.70 0.00 0.00 1.75 0.00 0.00 1.80 0.00 0.00 1.85 0.00 0.00 1.90 0.00 0.00 1.95 0.00 0.00 2.00 0.00 0.00 2.05 0.00 0.00 2.10 0.01 0.00 2.15 0.01 0.00 2.20 0.01 0.00 2.25 0.01 0.00 2.30 0.01 0.00 2.35 0.01 0.00 2.40 0.01 0.01 2.45 0.01 0.01 2.50 0.01 0.01 2.55 0.01 0.01 Time Subcat E-1 Subcat P-1 (hours) (cfs) (cfs) 2.60 0.01 0.01 2.65 0.01 0.01 2.70 0.01 0.01 2.75 0.01 0.01 2.80 0.01 0.01 2.85 0.01 0.01 2.90 0.01 0.01 2.95 0.01 0.01 3.00 0.01 0.01 3.05 0.01 0.01 3.10 0.01 0.01 3.15 0.01 0.01 3.20 0.01 0.01 3.25 0.01 0.01 3.30 0.01 0.01 3.35 0.01 0.01 3.40 0.01 0.01 3.45 0.01 0.01 3.50 0.01 0.01 3.55 0.01 0.01 3.60 0.01 0.01 3.65 0.01 0.01 3.70 0.01 0.01 3.75 0.01 0.01 3.80 0.01 0.01 3.85 0.01 0.01 3.90 0.01 0.01 3.95 0.01 0.01 4.00 0.01 0.01 4.05 0.01 0.01 4.10 0.01 0.01 4.15 0.01 0.01 4.20 0.01 0.01 4.25 0.01 0.01 4.30 0.01 0.01 4.35 0.01 0.01 4.40 0.01 0.01 4.45 0.01 0.01 4.50 0.01 0.01 4.55 0.01 0.01 4.60 0.01 0.01 4.65 0.01 0.01 4.70 0.01 0.01 4.75 0.01 0.01 4.80 0.01 0.01 4.85 0.01 0.01 4.90 0.01 0.01 4.95 0.01 0.01 5.00 0.01 0.01 5.05 0.01 0.01 5.10 0.01 0.01 5.15 0.01 0.01 Time Subcat E-1 Subcat

0 0.01 0.01 4.65 0.01 0.01 4.70 0.01 0.01 4.75 0.01 0.01 4.80 0.01 0.01 4.85 0.01 0.01 4.90 0.01 0.01 4.95 0.01 0.01 5.00 0.01 0.01 5.05 0.01 0.01 5.10 0.01 0.01 5.15 0.01 0.01 Time Subcat E-1 Subcat P-1 (hours) (cfs) (cfs) 5.20 0.01 0.01 5.25 0.01 0.01 5.30 0.01 0.01 5.35 0.01 0.01 5.40 0.02 0.01 5.45 0.02 0.01 5.50 0.02 0.01 5.55 0.02 0.01 5.60 0.02 0.01 5.65 0.02 0.01 5.70 0.02 0.01 5.75 0.02 0.01 5.80 0.02 0.01 5.85 0.02 0.01 5.90 0.02 0.01 5.95 0.02 0.01 6.00 0.02 0.01 6.05 0.02 0.01 6.10 0.02 0.01 6.15 0.02 0.01 6.20 0.02 0.01 6.25 0.02 0.01 6.30 0.02 0.01 6.35 0.02 0.01 6.40 0.02 0.01 6.45 0.02 0.02 6.50 0.02 0.02 6.55 0.02 0.02 6.60 0.02 0.02 6.65 0.02 0.02 6.70 0.02 0.02 6.75 0.02 0.02 6.80 0.02 0.02 6.85 0.02 0.02 6.90 0.02 0.02 6.95 0.02 0.02 7.00 0.02 0.02 7.05 0.02 0.02 7.10 0.02 0.02 7.15 0.02 0.02 7.20 0.02 0.02 7.25 0.02 0.02 7.30 0.02 0.02 7.35 0.02 0.02 7.40 0.02 0.02 7.45 0.02 0.02 7.50 0.02 0.02 7.55 0.02 0.02 7.60 0.03 0.02 7.65 0.03 0.02 7.70 0.03 0.02 7.75 0.03 0.02

NOAA 24-hr D 2-Year-2020 Rainfall=3.47", P2=3.47" Printed 8/13/2025 Prepared by Stonefield Engineering & Design 2025-08-13_Stormwater Calculations HydroCAD® 10.20-5c s/n 10626 © 2023 HydroCAD Software Solutions LLC Primary Comparison (continued) Time Subcat E-1 Subcat P-1 (hours) (cfs) (cfs) 7.80 0.03 0.02 7.85 0.03 0.02 7.90 0.03 0.02 7.95 0.03 0.02 8.00 0.03 0.02 8.05 0.03 0.02 8.10 0.03 0.02 8.15 0.03 0.02 8.20 0.03 0.02 8.25 0.03 0.02 8.30 0.03 0.02 8.35 0.03 0.02 8.40 0.03 0.02 8.45 0.03 0.02 8.50 0.03 0.02 8.55 0.03 0.02 8.60 0.03 0.02 8.65 0.03 0.03 8.70 0.03 0.03 8.75 0.03 0.03 8.80 0.03 0.03 8.85 0.03 0.03 8.90 0.03 0.03 8.95 0.03 0.03 9.00 0.03 0.03 9.05 0.03 0.03 9.10 0.03 0.03 9.15 0.04 0.03 9.20 0.04 0.03 9.25 0.04 0.03 9.30 0.04 0.03 9.35 0.04 0.03 9.40 0.04 0.03 9.45 0.04 0.03 9.50 0.04 0.03 9.55 0.04 0.04 9.60 0.04 0.04 9.65 0.05 0.04 9.70 0.05 0.04 9.75 0.05 0.04 9.80 0.05 0.04 9.85 0.05 0.04 9.90 0.05 0.04 9.95 0.05 0.04 10.00 0.05 0.04 10.05 0.05 0.04 10.10 0.05 0.04 10.15 0.05 0.04 10.20 0.06 0.04 10.25 0.06 0.05 10.30 0.06 0.05 10.35 0.06 0.05 Time Subcat E-1 Subcat P-1 (hours) (cfs) (cfs) 10.40 0.06 0.05 10.45 0.06 0.05 10.50 0.06 0.05 10.55 0.07 0.06 10.60 0.07 0.06 10.65 0.08 0.06 10.70 0.08 0.07 10.75 0.09 0.07 10.80 0.09 0.07 10.85 0.09 0.08 10.90 0.10 0.08 10.95 0.10 0.09 11.00 0.11 0.09 11.05 0.12 0.10 11.10 0.12 0.10 11.15 0.13 0.11 11.20 0.14 0.12 11.25 0.15 0.13 11.30 0.15 0.13 11.35 0.16 0.14 11.40 0.17 0.15 11.45 0.18 0.16 11.50 0.19 0.16 11.55 0.24 0.21 11.60 0.26 0.23 11.65 0.27 0.24 11.70 0.28 0.25 11.75 0.36 0.32 11.80 0.39 0.35 11.85 0.52 0.47 11.90 0.57 0.51 11.95 0.91 0.82 12.00 1.03 0.94 12.05 1.62 1.49 12.10 1.84 1.72 12.15 0.96 0.90 12.20 0.69 0.65 12.25 0.53 0.50 12.30 0.49 0.47 12.35 0.39 0.37 12.40 0.36 0.34 12.45 0.35 0.33 12.50 0.35 0.33 12.55 0.28 0.27 12.60 0.26 0.25 12.65 0.25 0.23 12.70 0.24 0.23 12.75 0.23 0.22 12.80 0.22 0.21 12.85 0.21 0.20 12.90 0.20 0.19 12.95 0.19 0.18 Time Subcat E-1 Subcat