SW6220101_Design Calculations (Time of Concentration)_20220614

[CALCULATIONS
sheet only set up to handle Tc from 5 min to 30 min
A. Flow velocity < 2.0 fps when discharging to wetlands B. Flow velocity < 4.5 fps all other cases"
Storm Event
Rainfall Intensity
5-min
10-min
15-min
30-min
10-yr
7.80
6.24
5.26
3.81
25-yr
8.71
6.94
5.87
4.35
50-yr
9.31
7.42
6.26
4.72
100-yr
9.891
7.851
6.62
5.07
Ditch No. Drainage Impervious Grassed C
Area (ac) I Area (ac) I Area (ac)
1 1.73 0.40 1.33 0.45
2 12.06 2.78 9.28 0.45
Tc
Kerby
Kirpich
L (11)
n s
Tom
L (11)
S
80.0
0.40 0.032
9.38 490.0
0.010
80.0
0.40 0.032
9.38 490.0
0.010
C. Channel slope < 5.0% for curb outlet swales
Rainfall
Storm) Intensity Q (cfs)
vent (yr E
Total Tc Tc Used (in/hr)
T,n
5.41 14.79
5.41 14.79
15 10-yr 5.26
15 10-yr 5.26
printed: 6/14/2022 2:28 PM Page 1 of 1