251203_42 ERW_Stormwater Report

251202_42 ERW Waystone - Future Rainfall NOAA 24-hr D 10-Year Rainfall=6.37" Prepared by Colliers Engineering & Design HydroCAD® 10.20-5c s/n 04431 © 2023 HydroCAD Software Solutions LLC Printed 12/3/2025 Page 25 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=3.91" Flow Length=203' Tc=5.9 min CN=78 Runoff=1.33 cfs 0.098 af Subcatchment PR 1B-I: Runoff Area=36,906 sf 100.00% Impervious Runoff Depth=6.13" Flow Length=136' Tc=1.5 min CN=98 Runoff=5.66 cfs 0.433 af Subcatchment PR 1B-P: Runoff Area=77,195 sf 0.00% Impervious Runoff Depth=4.01" Flow Length=195' Tc=7.7 min CN=79 Runoff=7.62 cfs 0.592 af Subcatchment PR 2-P: Runoff Area=7,405 sf 0.00% Impervious Runoff Depth=3.70" Flow Length=84' Slope=0.0833 '/' Tc=4.6 min CN=76 Runoff=0.74 cfs 0.052 af Reach 10R: Inflow=11.81 cfs 1.025 af Outflow=11.81 cfs 1.025 af Reach DP1-PR: Inflow=5.37 cfs 0.683 af Outflow=5.37 cfs 0.683 af Reach DP2-PR: Inflow=0.74 cfs 0.052 af Outflow=0.74 cfs 0.052 af Pond BASIN: Peak Elev=17.58' Storage=0.304 af Inflow=11.81 cfs 1.025 af Discarded=0.39 cfs 0.440 af Primary=4.70 cfs 0.585 af Outflow=5.09 cfs 1.025 af Total Runoff Area = 3.092 ac Runoff Volume = 1.176 af Average Runoff Depth = 4.57" 72.60% Pervious = 2.244 ac 27.40% Impervious = 0.847 ac