JMA02P003 262 270 Main Street Development Stormwater Management Report

Proposed Flows NOAA10 24-hr D 10-Year-Future Rainfall=6.31" Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Printed 5/26/2026 HydroCAD® 10.20-8a Sampler s/n S05110 © 2025 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Summary for Pond 5P: Porous Pavement B Inflow Area = 16,284 sf, 94.43% Impervious, Inflow Depth = 5.93" for 10-Year-Future event Inflow = 2.65 cfs @ 12.06 hrs, Volume= 8,041 cf Outflow = 0.15 cfs @ 13.37 hrs, Volume= 8,041 cf, Atten= 94%, Lag= 78.3 min Discarded = 0.07 cfs @ 8.75 hrs, Volume= 6,043 cf Primary = 0.08 cfs @ 13.37 hrs, Volume= 1,997 cf Routed to nonexistent node 6L Routing by Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.05 hrs Peak Elev= 97.56' @ 13.37 hrs Surf.Area= 5,690 sf Storage= 3,162 cf Plug-Flow detention time= 246.7 min calculated for 8,035 cf (100% of inflow) Center-of-Mass det. time= 246.8 min ( 992.1 - 745.3 ) Volume Invert Avail.Storage Storage Description #1 97.00' 14,225 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 97.00 5,690 0 0 98.00 5,690 5,690 5,690 99.00 5,690 5,690 11,380 99.50 5,690 2,845 14,225 Device Routing Invert Outlet Devices #1 Primary 97.20' 2.5" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #2 Discarded 97.00' 0.500 in/hr Exfiltration over Surface area Discarded OutFlow Max=0.07 cfs @ 8.75 hrs HW=97.03' (Free Discharge) 2=Exfiltration (Exfiltration Controls 0.07 cfs) Primary OutFlow Max=0.08 cfs @ 13.37 hrs HW=97.56' (Free Discharge) 1=Orifice/Grate

ed OutFlow Max=0.07 cfs @ 8.75 hrs HW=97.03' (Free Discharge) 2=Exfiltration (Exfiltration Controls 0.07 cfs) Primary OutFlow Max=0.08 cfs @ 13.37 hrs HW=97.56' (Free Discharge) 1=Orifice/Grate (Orifice Controls 0.08 cfs @ 2.42 fps)