Stormwater Management Report Revised as of 01282026 4936 0314 8685 v2

24-223 DRAINAGE DESIGN-PROPOSED-UPDATE NOAA 24-hr D 2-Year-2020 Rainfall=3.47", P2=3.47" Prepared by Jarmel Kizel Architects & Engnrs Printed 1/28/2026 HydroCAD® 10.20-6a s/n 12607 © 2024 HydroCAD Software Solutions LLC Page 11 Summary for Subcatchment P2: P-2 Pervious-w-offsite-Undisturbed Runoff = 0.47 cfs @ 12.37 hrs, Volume= 3,747 cf, Depth= 1.16" Routed to Link P-DP 1 : PROP DP 1 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.50 hrs NOAA 24-hr D 2-Year-2020 Rainfall=3.47", P2=3.47" Area (sf) CN Description * 2,744 98 Roof-offsite * 1,220 98 Impervious 1,506 71 Meadow, non-grazed, HSG C * 32,065 70 wooded * 1,240 74 >75% Grass offsite 38,775 73 Weighted Average 34,811 89.78% Pervious Area 3,964 10.22% 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" 1.8 110 0.0400 1.00 Shallow Concentrated Flow, SC Woodland Kv= 5.0 fps 0.6 115 0.0430 3.34 Shallow Concentrated Flow, Lawn Unpaved Kv= 16.1 fps 0.1 44 0.0500 12.75 15.65 Pipe Channel, Yard drains 15.0" Round Area= 1.2 sf Perim= 3.9' r= 0.31' n= 0.012 0.2 325 0.0440 31.42 888.36 Pipe Channel, Culvert 72.0" Round Area= 28.3 sf Perim= 18.8' r= 1.50' n= 0.013 14.0 694 Total