251203_42 ERW_Stormwater Report

250903_42 ERW Waystone - Future Rainfall NOAA 24-hr D 2-Year Rainfall=4.09" Prepared by Colliers Engineering & Design HydroCAD® 10.20-5c s/n 04431 © 2023 HydroCAD Software Solutions LLC Printed 11/25/2025 Page 4 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 EDA-1 (IMPERV): Runoff Area=13,913 sf 100.00% Impervious Runoff Depth=3.85" Flow Length=275' Tc=2.8 min CN=98 Runoff=1.36 cfs 0.103 af Subcatchment EDA-1 (PERV): Runoff Area=102,351 sf 0.00% Impervious Runoff Depth=1.66" Flow Length=501' Tc=13.1 min CN=74 Runoff=3.48 cfs 0.326 af Subcatchment EDA-2 (PERV.): Runoff Area=0.423 ac 0.00% Impervious Runoff Depth=1.66" Flow Length=121' Tc=7.2 min CN=74 Runoff=0.77 cfs 0.059 af Reach DP1-EX: Inflow=3.95 cfs 0.428 af Outflow=3.95 cfs 0.428 af Reach DP2-EX: Inflow=0.77 cfs 0.059 af Outflow=0.77 cfs 0.059 af Total Runoff Area = 3.092 ac Runoff Volume = 0.487 af Average Runoff Depth = 1.89" 89.67% Pervious = 2.773 ac 10.33% Impervious = 0.319 ac