250701_42 ERW_Stormwater Report

NOAA 24-hr D 2-Year Rainfall=3.44" 250624_42 ERW Waymaker Prepared by Colliers Engineering & Design HydroCAD® 10.20-5c s/n 04431 © 2023 HydroCAD Software Solutions LLC Printed 7/1/2025 Page 8 Summary for Subcatchment PR 1A-P: [49] Hint: Tc<2dt may require smaller dt Runoff = 0.50 cfs @ 12.13 hrs, Volume= Routed to Reach DP1-PR : 0.037 af, Depth= 1.45" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.05 hrs NOAA 24-hr D 2-Year Rainfall=3.44" Area (sf) 9,975 3,192 13,167 13,167 CN 74 89 78 Description >75% Grass cover, Good, HSG C Gravel roads, HSG C Weighted Average 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.6 100 0.0725 0.30 Sheet Flow, Grass: Short n= 0.150 P2= 3.44" 0.3 103 0.1090 5.32 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 5.9 203 Total Subcatchment PR 1A-P: Hydrograph 0.55 Runoff 0.50 cfs 0.5 0.45 0.4 Flow (cfs) 0.35 0.3 0.25 0.2 0.15 NOAA 24-hr D 2-Year Rainfall=3.44" Runoff Area=13,167 sf Runoff Volume=0.037 af Runoff Depth=1.45" Flow Length=203' Tc=5.9 min CN=78 0.1 0.05 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)