Stormwater Management Report Revised as of 01282026 4936 0314 8685 v2

24-223 DRAINAGE DESIGN-EXISTING-UPDATE NOAA 24-hr D 10-Year-2020 Rainfall=5.38", 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 27 Summary for Subcatchment E1C: E1C Pervious-w-offsite-Undisturbed Runoff = 1.02 cfs @ 12.27 hrs, Volume= 8,060 cf, Depth= 2.49" Routed to Link E-DP 1 : EXIST 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 10-Year-2020 Rainfall=5.38", P2=3.47" Area (sf) CN Description * 708 98 Roof-offsite * 1,220 98 Impervious 2,721 71 Meadow, non-grazed, HSG C * 32,886 70 wooded 1,240 74 >75% Grass cover, Good, HSG C 38,775 72 Weighted Average 36,847 95.03% Pervious Area 1,928 4.97% 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