Graham Place Subdivision <br />Type IA 24-hr 10-Year Rainfall=4.46"5468_HydroCAD_2-17-26_BAW <br /> Printed 7/9/2026Prepared by A&O Engineering LLC <br />Page 8HydroCAD® 10.20-8a s/n 04993 © 2025 HydroCAD Software Solutions LLC <br />Time span=0.00-48.00 hrs, dt=0.05 hrs, 961 points <br />Runoff by SBUH method, Split Pervious/Imperv. <br />Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method <br />Runoff Area=51,005 sf 15.29% Impervious Runoff Depth=2.49"Subcatchment 1489S: Existing Conditions <br /> Flow Length=210' Slope=0.0140 '/' Tc=13.1 min CN=77/98 Runoff=0.62 cfs 0.243 af <br />Runoff Area=3,223 sf 90.47% Impervious Runoff Depth=4.05"Subcatchment 1491S: Basin #1 <br /> Tc=10.0 min CN=80/98 Runoff=0.07 cfs 0.025 af <br />Runoff Area=2,394 sf 0.00% Impervious Runoff Depth=2.43"Subcatchment 1495S: Adjacent Landscape <br /> Tc=10.0 min CN=80/0 Runoff=0.03 cfs 0.011 af <br />Runoff Area=2,841 sf 100.00% Impervious Runoff Depth=4.22"Subcatchment 1496S: Water Surface <br /> Tc=0.0 min CN=0/98 Runoff=0.07 cfs 0.023 af <br />Runoff Area=13,983 sf 78.70% Impervious Runoff Depth=3.84"Subcatchment 1511S: Basin #2 <br /> Tc=10.0 min CN=80/98 Runoff=0.29 cfs 0.103 af <br />Runoff Area=16,146 sf 92.04% Impervious Runoff Depth=4.08"Subcatchment 1512S: Basin #3 <br /> Tc=10.0 min CN=80/98 Runoff=0.36 cfs 0.126 af <br />Runoff Area=13,627 sf 79.48% Impervious Runoff Depth=3.86"Subcatchment 1513S: Basin #4 <br /> Tc=10.0 min CN=80/98 Runoff=0.28 cfs 0.101 af <br /> Inflow=0.52 cfs 0.388 afReach 1480R: Public System <br /> Outflow=0.52 cfs 0.388 af <br />Avg. Flow Depth=0.00' Max Vel=0.00 fpsReach 1481R: Catch Basin #2 Outlet <br />8.0" Round Pipe n=0.010 L=30.0' S=0.0063 '/' Capacity=1.25 cfs Outflow=0.00 cfs 0.000 af <br />Peak Elev=422.68' Storage=0.001 af Inflow=0.90 cfs 0.388 afPond 1479P: CB #1 (PUMP) 240 <br /> Outflow=0.52 cfs 0.388 af <br />Peak Elev=422.42' Inflow=1.00 cfs 0.354 afPond 1492P: Catch Basin #2 <br />8.0" Round Culvert n=0.010 L=28.0' S=0.0068 '/' Outflow=1.00 cfs 0.354 af <br />Peak Elev=422.55' Inflow=0.93 cfs 0.329 afPond 1497P: Catch Basin #3 <br />8.0" Round Culvert n=0.010 L=63.0' S=0.0090 '/' Outflow=0.93 cfs 0.329 af <br />Peak Elev=422.76' Inflow=0.64 cfs 0.227 afPond 1498P: Catch Basin #4 <br />8.0" Round Culvert n=0.010 L=108.0' S=0.0050 '/' Outflow=0.64 cfs 0.227 af <br />Peak Elev=422.91' Inflow=0.28 cfs 0.101 afPond 1507P: Catch Basin #5 <br />6.0" Round Culvert n=0.010 L=99.0' S=0.0051 '/' Outflow=0.28 cfs 0.101 af <br />Peak Elev=422.38' Storage=4,917 cf Inflow=1.10 cfs 0.388 afPond 1508P: Rain Garden <br /> Outflow=0.90 cfs 0.388 af <br />Total Runoff Area = 2.370 ac Runoff Volume = 0.631 af Average Runoff Depth = 3.20" <br />51.32% Pervious = 1.216 ac 48.68% Impervious = 1.154 ac