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230550 HydroCAD
Concept HydroCAD-230550 Type II 24-hr 100-yr Rainfall=8.10"
Prepared by Lane Engineering, LLC Printed 5/26/2025
HydroCAD® 10.00-17 s/n 03788 © 2016 HydroCAD Software Solutions LLC Page 20

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

Runoff = 6.39 cfs @ 12.28 hrs, Volume= 0.976 af, Depth> 5.65"

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 100-yr Rainfall=8.10"

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

7 Runoff
6.39 cfs
Type II 24-hr
6
100-yr Rainfall=8.10"
Runoff Area=90,272 sf
5
Runoff Volume=0.976 af
Flow (cfs) Runoff Depth>5.65"
4

3 Flow Length=431'
Tc=30.7 min
2 CN=80

1

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

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