Analysis - Failure NOAA 24-hr D 10 YR-C Rainfall=5.38" Prepared by Civil Core Consulting Printed 12/19/2025 HydroCAD® 10.20-8a s/n 13637 © 2025 HydroCAD Software Solutions LLC Page 138
Summary for Pond 3P: PERVIOUS PAVEMENT 2B
Inflow Area = 8,276 sf,100.00% Impervious, Inflow Depth = 5.14" for 10 YR-C event
Inflow = 0.89 cfs @ 12.12 hrs, Volume= 3,547 cf
Outflow = 0.58 cfs @ 12.21 hrs, Volume= 3,543 cf, Atten= 35%, Lag= 5.4 min
Primary = 0.58 cfs @ 12.21 hrs, Volume= 3,543 cf
Routed to Pond 33P : INELL TRATION BASIN 2
Routed to Pond 33P : INFILTRATION BASIN 2
Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs / 3 Peak Elevation = 94.84' @ 12.22 hrs Surf. Area = 9,225 sf Storage = 975 cf Plug-Flow detention time = 134.8 min calculated for 3,542 cf (100% of inflow) Center-of-Mass det. time = 134.4 min (883.4 - 749.1)
VolumeInvertAvail.StorageStorage Description
#193.80'615 cfStone Storage Bed (Prismatic)Listed below (Recalc) 1,538 cf Overall × 40.0% Voids
#294.30'231 cfSurface and Base Course (Prismatic)Listed below (Recalc) 1,538 cf Overall × 15.0% Voids
#394.80'1,538 cfSurface (Prismatic)Listed below (Recalc)
2,383 cfTotal Available Storage
Elevation (feet)Surf.Area (sq-ft)Inc.Store (cubic-feet)Cum.Store (cubic-feet)
93.803,07500
94.303,0751,5381,538
Elevation (feet)Surf.Area (sq-ft)Inc.Store (cubic-feet)Cum.Store (cubic-feet)
94.303,07500
94.803,0751,5381,538
Elevation (feet)Surf.Area (sq-ft)Inc.Store (cubic-feet)Cum.Store (cubic-feet)
94.803,07500
95.303,0751,5381,538
DeviceRoutingInvertOutlet Devices
#1Device 393.80'2.5" Vert. Orifice C = 0.600
#2Device 394.80'48.0" x 48.0" Horiz. Grate C = 0.600
#3Primary92.08'12.0" Round Culvert L = 38.0' RCP, groove end projecting, Ke = 0.200Inlet / Outlet Invert= $ 92.08'/91.65' $ S = 0.0113'/' Cc = 0.900n=0.011, Flow Area=0.79 sf
Primary OutFlow Max=0.58 cfs @ 12.21 hrs HW=94.84' TW=94.23' (Dynamic Tailwater) 3=Culvert (Passes 0.58 cfs of 3.43 cfs potential flow) 1=Orifice (Orifice Controls 0.13 cfs @ 3.76 fps) 2=Grate (Weir Controls 0.45 cfs @ 0.67 fps)