Drainage Report and Supplement 82625

NOAA 24-hr D 2-Year-2050 Rainfall=4.09", P2=4.09" 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 Page 29 Time span=0.00-72.00 hrs, dt=0.01 hrs, 7201 points Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv. Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Runoff Area=32,101 sf 45.25% Impervious Runoff Depth=2.65" Flow Length=147' Tc=2.5 min CN=74/98 Runoff=2.31 cfs 7,101 cf Subcatchment E-1: Existing Drainage to Runoff Area=143,746 sf 24.72% Impervious Runoff Depth=2.37" Flow Length=408' Tc=2.8 min CN=77/98 Runoff=9.65 cfs 28,391 cf Subcatchment E-2: Existing Drainage to Subcatchment P-1: Proposed Drainage to Runoff Area=32,238 sf 36.29% Impervious Runoff Depth=2.46" Flow Length=178' Tc=2.5 min CN=74/98 Runoff=2.18 cfs 6,604 cf Subcatchment P-2: Proposed Drainage to Runoff Area=143,609 sf 24.31% Impervious Runoff Depth=2.36" Flow Length=408' Tc=2.8 min CN=77/98 Runoff=9.61 cfs 28,267 cf Total Runoff Area = 351,694 sf Runoff Volume = 70,363 cf Average Runoff Depth = 2.40" 72.51% Pervious = 255,029 sf 27.49% Impervious = 96,665 sf