POST DEV NOAA 24-hr D 2 YEAR Rainfall=3.42" Prepared by Professional Design Services Printed 12/31/2025 HydroCAD® 10.20-6a s/n 02223 © 2024 HydroCAD Software Solutions LLC Page 19
Summary for Pond 8P: SSIB #2 UNDERGROUND
[82] Warning: Early inflow requires earlier time span
Inflow Area = 0.460 ac, 58.70% Impervious, Inflow Depth > 1.71" for 2 YEAR event Inflow = 0.93 cfs @ 12.08 hrs, Volume= 0.066 af Outflow = 0.09 cfs @ 12.99 hrs, Volume= 0.065 af, Atten= 91%, Lag= 54.4 min Discarded = 0.09 cfs @ 12.99 hrs, Volume= 0.065 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= 108.37' @ 12.99 hrs Surf.Area= 0.064 ac Storage= 0.025 af Plug-Flow detention time= 100.6 min calculated for 0.065 af (99% of inflow) Center-of-Mass det. time= 98.8 min (834.8 - 736.1)
VolumeInvertAvail.StorageStorage Description
#1A107.50'0.048 af41.95"W x 66.33"L x 3.00"H Field A
0.192 af Overall - 0.072 af Embedded = 0.120 af x 40.0% Voids
#2A107.83'0.057 afADS N-12 24" x 36 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 36 Chambers in 12 Rows 40.28' Header x 3.10 sf x 2 = 249.8 cf Inside
0.105 afTotal Available Storage
0.105 af Total Available Storage
Storage Group A created with Chamber Wizard
DeviceRoutingInvertOutlet Devices
#1Discarded107.50'1.000 in/hr Exfiltration over Surface area Conductivity to Groundwater Elevation = 105.00'
#2Primary109.00'8.0" W x 4.0" H Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads
Discarded OutFlowMax=0.09 cfs @ 12.99 hrsHW=108.37' (Free Discharge)
1=Exfiltration ( Controls 0.09 cfs)
Primary OutFlowMax=0.00 cfs @ 5.00 hrsHW=107.50' (Free Discharge)
2=Orifice/Grate ( Controls 0.00 cfs)