251203_42 ERW_Stormwater Report

251202_42 ERW Waystone - Future Rainfall NOAA 24-hr D 25-Year Rainfall=6.44" Prepared by Colliers Engineering & Design HydroCAD® 10.20-5c s/n 04431 © 2023 HydroCAD Software Solutions LLC Printed 12/3/2025 Page 46 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=3.97" Flow Length=203' Tc=5.9 min CN=78 Runoff=1.36 cfs 0.100 af Subcatchment PR 1B-I: Runoff Area=36,906 sf 100.00% Impervious Runoff Depth=6.20" Flow Length=136' Tc=1.5 min CN=98 Runoff=5.73 cfs 0.438 af Subcatchment PR 1B-P: Runoff Area=77,195 sf 0.00% Impervious Runoff Depth=4.07" Flow Length=195' Tc=7.7 min CN=79 Runoff=7.74 cfs 0.602 af Subcatchment PR 2-P: Runoff Area=7,405 sf 0.00% Impervious Runoff Depth=3.76" Flow Length=84' Slope=0.0833 '/' Tc=4.6 min CN=76 Runoff=0.76 cfs 0.053 af Reach 10R: Inflow=11.97 cfs 1.040 af Outflow=11.97 cfs 1.040 af Reach DP1-PR: Inflow=5.46 cfs 0.697 af Outflow=5.46 cfs 0.697 af Reach DP2-PR: Inflow=0.76 cfs 0.053 af Outflow=0.76 cfs 0.053 af Pond BASIN: Peak Elev=17.61' Storage=0.308 af Inflow=11.97 cfs 1.040 af Discarded=0.39 cfs 0.443 af Primary=4.78 cfs 0.597 af Outflow=5.17 cfs 1.040 af Total Runoff Area = 3.092 ac Runoff Volume = 1.193 af Average Runoff Depth = 4.63" 72.60% Pervious = 2.244 ac 27.40% Impervious = 0.847 ac