Drainage Report and Supplement 82625

NOAA 24-hr D 10-Year-2020 Rainfall=5.38", 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 Page 16 Summary for Subcatchment P-1: Proposed Drainage to Woodland Avenue Runoff = 3.16 cfs @ 12.10 hrs, Volume= Routed to nonexistent node P0I-1 9,585 cf, Depth= 3.57" 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 10-Year-2020 Rainfall=5.38", P2=3.47" * * Area (sf) 11,698 9,040 11,500 32,238 20,540 11,698 Tc (min) 1.8 Length (feet) 23 0.1 9 0.2 41 0.2 43 0.2 36 0.1 26 2.6 178 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 0.21 Sheet Flow, B1-B2 Grass: Short n= 0.150 P2= 3.47" 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