NOAA 24-hr D 2 YR-F Rainfall=4.04" Printed 12/19/2025 s LLC Page 102
Analysis - Proposed Conditions NOA Prepared by Civil Core Consulting HydroCAD® 10.20-8a s/n 13637 © 2025 HydroCAD Software Solutions LLC
Summary for Pond 5P: BIORETENTION BASIN 1A
Inflow Area = 70,567 sf, 24.69% Impervious, Inflow Depth = 0.98" for 2 YR-F event Inflow = 1.58 cfs @ 12.11 hrs, Volume = 5,747 cf Outflow = 0.17 cfs @ 12.89 hrs, Volume = 4,241 cf, Atten = 89%, Lag = 46.7 min Primary = 0.17 cfs @ 12.89 hrs, Volume = 4,241 cf Routed to Pond 2P : Subsurface Infiltration Basin 1
Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Peak Elev= 92.21' @ 12.89 hrs Surf.Area= 1,500 sf Storage= 3,321 cf Plug-Flow detention time= 336.9 min calculated for 4,241 cf (74% of inflow) Center-of-Mass det. time= 229.7 min ( 997.3 - 767.6 )
VolumeInvertAvail.StorageStorage Description
#190.00'8,250 cfCustom Stage Data (Prismatic)Listed below (Recalc)
Elevation (feet)Surf.Area (sq-ft)Inc.Store (cubic-feet)Cum.Store (cubic-feet)
90.001,50000
95.501,5008,2508,250
DeviceRoutingInvertOutlet Devices
#1Device 391.00'2.5" Vert. Orifice C = 0.600 Limited to weir flow at low heads
#2Device 395.00'48.0" x 48.0" Horiz. Grate C = 0.600 Limited to weir flow at low heads
#3Primary87.48'12.0" Round Culvert\n L = 28.0' RCP, groove end projecting, Ke = 0.200\nInlet / Outlet Invert= $ 87.48'/87.00' $ S = 0.0171'/' Cc = 0.900\n n = 0.012 Concrete pipe, finished, Flow Area= $ 0.79sf $
Primary OutFlow Max=0.17 cfs @ 12.89 hrs HW=92.21' TW=87.00' (Dynamic Tailwater) 3=Culvert (Passes 0.17 cfs of 9.27 cfs potential flow) 1=Orifice (Orifice Controls 0.17 cfs @ 5.07 fps) 2=Grate ( Controls 0.00 cfs)
Pond 5P: BIORETENTION BASIN 1A Orifice