OCSCD 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 32
Summary for Pond 3P: SSIB #1 SURFACE BASIN
nflow Area = 1.070 ac, 67.29% Impervious, Inflow Depth > 3.21" for 10 YEAR event
nflow = 2.16 cfs @ 12.22 hrs, Volume= 0.286 af
Outflow = 1.22 cfs @ 12.58 hrs, Volume= 0.281 af, Atten= 43%, Lag= 21.1 min
Discarded = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af
Primary = 1.22 cfs @ 12.58 hrs, Volume= 0.281 af
Routed to Reach 10 : COMPOSITE
Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Starting Elev= 111.50' Surf.Area= 2,825 sf Storage= 3,544 cf Peak Elev= 112.25' @ 12.58 hrs Surf.Area= 3,402 sf Storage= 5,884 cf (2,340 cf above start)
Plug-Flow detention time= 164.2 min calculated for 0.199 af (69% of inflow)
Plug-Flow detention time = 164.2 min calculated for 0.199 af (69% of inflow) Center-of-Mass det. time = 27.0 min (777.3 - 750.3)
VolumeInvertAvail.StorageStorage Description
#1110.00'12,950 cfCustom Stage Data (Prismatic)Listed below (Recalc)
Elevation (feet)Surf.Area (sq-ft)Inc.Store (cubic-feet)Cum.Store (cubic-feet)
110.002,00000
111.002,4502,2252,225
112.003,2002,8255,050
113.004,0003,6008,650
114.004,6004,30012,950
DeviceRoutingInvertOutlet Devices
#1Discarded110.00'1.000 in/hr Exfiltration X 0.00 over Surface area Conductivity to Groundwater Elevation = 106.00'
#2Primary111.50'12.0" W x 4.0" H Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads
#3Primary113.00'24.0" x 48.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads
Discarded OutFlow Max=0.00 cfs @ 5.00 hrs HW=111.50' (Free Discharge)
Discarded OutFlow Max=0.00 cfs @ 5.00 hrs HW=1111.50' (Free Discharge) 1=Exfiltration (Controls 0.00 cfs)
Primary OutFlow Max=1.22 cfs @ 12.58 hrs HW=112.25' (Free Discharge) 2=Orifice/Grate (Orifice Controls 1.22 cfs @ 3.67 fps) 3=Orifice/Grate (Controls 0.00 cfs)