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230550 HydroCAD
Concept HydroCAD-230550 Type II 24-hr 2-yr Rainfall=3.60"
Prepared by Lane Engineering, LLC Printed 5/26/2025
HydroCAD® 10.00-17 s/n 03788 © 2016 HydroCAD Software Solutions LLC Page 2

Summary for Subcatchment 1S: PRE-1 (Yellow)

Runoff = 1.87 cfs @ 12.29 hrs, Volume= 0.292 af, Depth> 1.69"

Runoff by SCS TR-20 method, UH=Delmarva, Weighted-CN, Time Span= 0.10-24.01 hrs, dt= 0.03 hrs
Type II 24-hr 2-yr Rainfall=3.60"

Area (sf) CN Description
254 98 Paved parking, HSG D
90,018 80 >75% Grass cover, Good, HSG D
90,272 80 Weighted Average
90,018 99.72% Pervious Area
254 0.28% Impervious Area

Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
28.8 250 0.0200 0.14 Sheet Flow, a-b sheetflow
Grass: Dense n= 0.240 P2= 3.40"
1.9 181 0.0100 1.61 Shallow Concentrated Flow, b-c shallow grass
Unpaved Kv= 16.1 fps
30.7 431 Total

Subcatchment 1S: PRE-1 (Yellow)
Hydrograph

Runoff
2
1.87 cfs
Type II 24-hr
2-yr Rainfall=3.60"
Runoff Area=90,272 sf
Runoff Volume=0.292 af
Flow (cfs) 1 Runoff Depth>1.69"

Flow Length=431'

Tc=30.7 min
CN=80

0
2 4 6 8 10 12 14 16 18 20 22 24
Time (hours)

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