POST DEV NOAA 24-hr D 25 year Rainfall=6.68" Prepared by Professional Design Services Printed 12/31/2025 HydroCAD® 10.20-6a s/n 02223 © 2024 HydroCAD Software Solutions LLC Page 61
Summary for Pond 3P: SSIB #1 SURFACE BASIN
[82] Warning: Early inflow requires earlier time span
Inflow Area = 1.290 ac, 55.81% Impervious, Inflow Depth > 3.48" for 25 year event Inflow = 2.75 cfs @ 12.23 hrs, Volume= 0.374 af Outflow = 1.41 cfs @ 12.65 hrs, Volume= 0.291 af, Atten=49%, Lag=25.4 min Discarded = 0.11 cfs @ 12.65 hrs, Volume= 0.093 af Primary = 1.30 cfs @ 12.65 hrs, Volume= 0.199 af Routed to Reach 10 : COMPOSITE Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Peak Elev= 112.33' @ 12.65 hrs Surf.Area= 3,460 sf Storage= 6,132 cf Plug-Flow detention time= 120.4 min calculated for 0.290 af (78% of inflow) Center-of-Mass det. time= 58.6 min ( 813.8 - 755.2 )
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 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=0.11 cfs @ 12.65 hrs HW=112.32' (Free Discharge) 1=Exfiltration (Controls 0.11 cfs)
Primary OutFlow Max=1.30 cfs @ 12.65 hrs HW=112.32' (Free Discharge) 2=Orifice/Grate (Orifice Controls 1.30 cfs @ 3.90 fps) 3=Orifice/Grate (Controls 0.00 cfs)