SW6220602_Design Calculations (Time of Concentration)_20220810

[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* * C. Channel slope < 5.0% for curb outlet swales
Storm Event
Rainfall Intensity
5-min
10-min
15-min
30-min
10-yr
7.99
6.39
5.39
3.90
25-yr
8.96
7.15
6.04
4.47
50-yr
9.70
7.72
6.52
4.91
100-yr
10.40
8.27
6.97
5.34
Drainage
Impervious
Grassed
TC
Storm
Rainfall
Ditch No.
C
Kerby
Kirpich
Intensity
Q (cfs)
Area (ac)
Area (ac)
Area (ac)
Event (yr)
Total Tc
Tc Used
(in/hr)
L (ft) n s
Tnv
L (ft)
S
Tch
1
0.09
0.03
0.06
0.50
n/a
115.0
0.003
2.82
2.82
5
10-yr
7.99
0.36
2
0.10
0.03
0.07
0.50
n/a
150.0
0.005
2.84
2.84
5
10-yr
7.99
0.40
3
4.39
0.68
3.71
0.40
n/a
875.0
0.007
9.71
9.71
10
10-yr
6.39
11.22
4
0.12
0.04
0.08
0.50
n/a
175.0
0.005
3.20
3.20
5
10-yr
7.99
0.48
5
0.17
0.05
0.12
0.50
n/a
250.0
0.012
3.01
3.01
5
10-yr
7.99
0.68
6
5.76
0.44
5.32
0.35
n/a
600.0
0.010
6.33
6.33
5
10-yr
7.99
16.11
7
5.83
0.45
5.38
0.35
n/a
745.0
0.010
7.48
7.48
5
10-yr
7.99
16.30
8
0.18
0.06
0.12
0.50
n/a
255.0
0.005
4.28
4.28
5
10-yr
7.99
0.72
9
0.70
0.22
0.48
0.50
n/a
500.0
0.006
6.69
6.69
5
10-yr
7.99
2.80
10
1.48
0.34
1.14
0.45
n/a
650.0
0.006
8.19
8.19
10
10-yr
6.39
4.26
11
0.66
0.15
0.51
0.45
n/a
250.0
0.008
3.51
3.51
5
10-yr
7.99
2.37
12
0.09
0.03
0.06
0.50
n/a
135.0
0.005
2.62
2.62
5
10-yr
7.99
0.36
13
2.19
0.34
1.85
0.40
n/a
1000.0
0.008
10.22
10.22
10
10-yr
6.39
5.60
14
0.29
0.09
0.20
0.50
n/a
410.0
0.005
6.16
6.16
5
10-yr
7.99
1.16
15
5.86
0.90
4.96
0.40
n/a
1100.0
0.008
11.00
11.00
10
10-yr
6.39
14.98
16
0.15
0.05
0.10
0.50
n/a
200.0
0.005
3.55
3.55
5
10-yr
7.99
0.60
17
0.42
0.13
0.29
0.50
n/a
485.0
0.008
5.85
5.85
5
10-yr
7.99
1.68
18
11.50
0.88
10.62
0.35
n/a
1400.0
0.007
13.94
13.94
15
10-yr
5.39
21.69
19
1.76
0.27
1.49
0.40
n/a
885.0
0.008
9.30
9.30
10
10-yr
6.39
4.50
20
1.32
0.20
1.12
0.40
n/a
670.0
0.005
9.00
9.00
10
10-yr
6.39
3.37
21
1.75
0.00
1.75
0.30
n/a
410.0
0.015
4.04
4.04
5
10-yr
7.99
4.19
22
4.64
0.36
4.28
0.35
n/a
765.0
0.010
7.63
7.63
10
10-yr
6.39
10.38
23
0.94
0.14
0.80
0.40
n/a
350.0
0.010
4.18
4.18
5
10-vr
7.99
3.00
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Ditch No.
Drainage
Area (ac)
hnpervious
Area (ac)
Grassed
Area (ac)
C
Tc
Storm
Event (yr)
Rainfall
lntensity
Q (cfs)
Kerby
Kirpich
Total Tc
Tc Used
L ft n s
T_
L ft
S
Tch
in/hr
24
0.91
0.14
0.77
0.40
n/a
400.0
0.015
3.96
3.96
5
10-yr
7.99
2.91
25
2.12
0.16
1.96
0.35
n/a
515.0
0.008
6.13
6.13
5
10-yr
7.99
5.93
26
1.02
0.16
0.86
0.40
n/a
360.0
0.010
4.27
4.27
5
10-yr
7.99
3.26
27
1.36
0.00
1.36
0.30
n/a
515.0
0.010
5.63
5.63
5
10-yr
7.99
3.26
28
1.65
0.25
1.40
0.40
n/a
620.0
0.010
6.49
6.49
5
10-yr
7.99
5.27
29
0.50
0.00
0.50
0.30
n/a
340.0
0.015
3.50
3.50
5
10-yr
7.99
1.20
30
0.99
0.08
0.91
0.35
n/a
425.0
0.010
4.85
4.85
5
10-yr
7.99
2.77
31
1.30
0.10
1.20
0.35
n/a
460.0
0.010
5.16
5.16
5
10-yr
7.99
3.64
32
0.82
0.00
0.82
0.30
n/a
300.0
0.020
2.84
2.84
5
10-yr
7.99
1.97
33
1.62
0.12
1.50
0.35
n/a
485.0
0.015
4.60
4.60
5
10-yr
7.99
4.53
34
2.22
0.17
2.05
0.35
n/a
550.0
0.010
5.92
5.92
5
10-yr
7.99
6.21
35
0.25
0.00
0.25
0.30
n/a
420.0
0.015
4.11
4.11
5
10-yr
7.99
0.60
36
1.30
0.10
1.20
0.35
n/a
690.0
0.010
7.05
7.05
5
10-yr
7.99
3.64
37
0.09
0.02
0.07
0.45
n/a
90.0
0.005
1.92
1.92
5
10-yr
7.99
0.32
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