POST DEV NOAA 24-hr D 10 YEAR Rainfall=5.38" Prepared by Professional Design Services Printed 12/31/2025 HydroCAD® 10.20-6a s/n 02223 © 2024 HydroCAD Software Solutions LLC Page 47
Summary for Pond 9P: SSIB #3 UNDERGROUND
[82] Warning: Early inflow requires earlier time span
Inflow Area = 0.460 ac,100.00% Impervious, Inflow Depth > 4.66" for 10 YEAR event Inflow = 2.35 cfs @ 12.10 hrs, Volume= 0.179 af Outflow = 0.14 cfs @ 13.59 hrs, Volume= 0.127 af, Atten= 94%, Lag= 89.8 min Discarded = 0.14 cfs @ 13.59 hrs, Volume= 0.127 af Primary = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af Routed to Reach 10 : COMPOSITE Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Peak Elev= 112.59' @ 13.59 hrs Surf.Area= 0.085 ac Storage= 0.087 af Plug-Flow detention time= 170.1 min calculated for 0.127 af (71% of inflow) Center-of-Mass det. time= 99.5 min ( 833.8 - 734.2 )
VolumeInvertAvail.StorageStorage Description
#1A110.80'0.063 af55.75'W x 66.33'L x 3.00'H Field A
0.255 af Overall - 0.096 af Embedded = 0.159 af x 40.0% Voids
#2A111.13'0.076 afADS N-12 24" x 48 Inside #1 Inside = 23.8"W x 23.8"H => 3.10 sf x 20.00'L = 62.0 cf Outside = 28.0"W x 28.0"H => 3.92 sf x 20.00'L = 78.4 cf 48 Chambers in 16 Rows 54.08' Header x 3.10 sf x 2 = 335.3 cf Inside
0.139 afTotal Available Storage
0.139 af Total Available Storage
Storage Group A created with Chamber Wizard
DeviceRoutingInvertOutlet Devices
#1Discarded110.80'1.000 in/hr Exfiltration over Surface area Conductivity to Groundwater Elevation = 108.00'
#2Primary113.00'12.0" W x 6.0" H Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads
Discarded OutFlowMax=0.14 cfs @ 13.59 hrs HW=112.59' (Free Discharge)
1=Exfiltration ( Controls 0.14 cfs)
Primary OutFlowMax=0.00 cfs @ 5.00 hrs HW=110.80' (Free Discharge)
2=Orifice/Grate ( Controls 0.00 cfs)