2026 05 Storm Water Management Report rcd 5 6 2026

2026-04 Proposed & Existing Conditi NOAA 24-hr D 2-Year-Current Rainfall=3.47", P2=3.47" 2026-04 Proposed & Existing Conditi NOAA 24-hr D 2-Year-Current Rainfall=3.47", P2=3.47" Prepared by Dynamic Engineering Printed 5/5/2026 Prepared by Dynamic Engineering Printed 5/5/2026 HydroCAD® 10.20-7a s/n 08640 © 2025 HydroCAD Software Solutions LLC Page 11 HydroCAD® 10.20-7a s/n 08640 © 2025 HydroCAD Software Solutions LLC Page 12 Summary for Pond 1P: UG BASIN Pond 1P: UG BASIN Hydrograph Inflow Area = 0.142 ac,100.00% Impervious, Inflow Depth = 3.24" for 2-Year-Current event Inflow = 0.51 cfs @ 12.10 hrs, Volume= 0.038 af 0.51 cfs Inflow Primary Outflow = 0.24 cfs @ 12.12 hrs, Volume= 0.038 af, Atten= 53%, Lag= 1.2 min 0.55 Primary = 0.24 cfs @ 12.12 hrs, Volume= 0.038 af 0.5 Inflow Area=0.142 ac Routed to Link 4L : POI #1 0.45

0.142 ac Routed to Link 4L : POI #1 0.45 Peak Elev=618.91' Routing by Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.001 hrs Peak Elev= 618.91' @ 12.12 hrs Surf.Area= 0.006 ac Storage= 0.005 af 0.4 Storage=0.005 af 0.35 Plug-Flow detention time= 7.0 min calculated for 0.038 af (100% of inflow) Flow (cfs) Center-of-Mass det. time= 7.0 min ( 758.9 - 751.9 ) 0.3 0.24 cfs 0.25 Volume Invert Avail.Storage Storage Description #1 617.75' 0.020 af 48.0" Round Pipe Storage 0.2 L= 70.0' 0.15 Device Routing Invert Outlet Devices 0.1 #1 Primary 617.75' 15.0" Round RCP_Round 15" 0.05 L= 15.0' RCP, rounded edge headwall, Ke= 0.100 Inlet / Outlet Invert= 617.75' / 617.55' S= 0.0133 '/' Cc= 0.900 0

Outlet Invert= 617.75' / 617.55' S= 0.0133 '/' Cc= 0.900 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 n= 0.012 Concrete pipe, finished, Flow Area= 1.23 sf Time (hours) #2 Device 1 617.75' 3.0" Vert. Orifice C= 0.600 Limited to weir flow at low heads #3 Device 1 620.25' 6.0" Vert. Orifice C= 0.600 Limited to weir flow at low heads #4 Device 1 621.45' 4.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s) Primary OutFlow Max=0.24 cfs @ 12.12 hrs HW=618.91' (Free Discharge) 1=RCP_Round 15" (Passes 0.24 cfs of 4.42 cfs potential flow) 2=Orifice (Orifice Controls 0.24 cfs @ 4.89 fps) 3=Orifice ( Controls 0.00 cfs) 4=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs)