251203_42 ERW_Stormwater Report

251202_42 ERW Waystone - Future Rainfall NOAA 24-hr D 100-Year Rainfall=11.52" Prepared by Colliers Engineering & Design HydroCAD® 10.20-5c s/n 04431 © 2023 HydroCAD Software Solutions LLC Printed 12/3/2025 Page 67 Time span=0.00-72.00 hrs, dt=0.05 hrs, 1441 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment PR 1A-P: Runoff Area=13,167 sf 0.00% Impervious Runoff Depth=8.71" Flow Length=203' Tc=5.9 min CN=78 Runoff=2.86 cfs 0.219 af Subcatchment PR 1B-I: Runoff Area=36,906 sf 100.00% Impervious Runoff Depth=11.28" Flow Length=136' Tc=1.5 min CN=98 Runoff=10.27 cfs 0.796 af Subcatchment PR 1B-P: Runoff Area=77,195 sf 0.00% Impervious Runoff Depth=8.85" Flow Length=195' Tc=7.7 min CN=79 Runoff=16.19 cfs 1.307 af Subcatchment PR 2-P: Runoff Area=7,405 sf 0.00% Impervious Runoff Depth=8.44" Flow Length=84' Slope=0.0833 '/' Tc=4.6 min CN=76 Runoff=1.64 cfs 0.120 af Reach 10R: Inflow=23.63 cfs 2.103 af Outflow=23.63 cfs 2.103 af Reach DP1-PR: Inflow=14.42 cfs 1.772 af Outflow=14.42 cfs 1.772 af Reach DP2-PR: Inflow=1.64 cfs 0.120 af Outflow=1.64 cfs 0.120 af Pond BASIN: Peak Elev=19.87' Storage=0.531 af Inflow=23.63 cfs 2.103 af Discarded=0.58 cfs 0.550 af Primary=12.86 cfs 1.553 af Outflow=13.44 cfs 2.103 af Total Runoff Area = 3.092 ac Runoff Volume = 2.442 af Average Runoff Depth = 9.48" 72.60% Pervious = 2.244 ac 27.40% Impervious = 0.847 ac