SW6241002_Design Calculations_20241118

Marsh Enn -ineering Services dil
DITCH CALCULATIONS
PROJECT 9-POWDER HO 11 N SU 1 DIVISION
Rainfall Intensity
Storm
Event 5-min 10-min 15-min 30-min Runoff Coefficient
10-yr 7.96 6.36 5.36 3.88 Impervious 0.95
25-yr 8.88 7.07 5.98 4.43 Grassed 0.3
50-yr 9.59 7.63 6.44 4.85
100-yr 10.30 8.15 6.87 5.26
T,
Drainage Impervious Grassed Storm Event Rainfall
Ditch No. C Kirpich Intensity Q(cfs)
Area(ac) Area(ac) Area(ac) T,Used (yr) (in/hr)
L(ft) S Tch
1 1.22 0.19 1.03 0.40 825 0.0165 6.67 5 10-yr 7.96 3.88
2 0.44 0.07 0.37 0.40 390 0.0200 3.48 5 10-yr 7.96 1.40
3 0.72 0.11 0.61 0.40 515 0.0171 4.58 5 10-yr 7.96 2.29
4 0.16 0.06 0.10 0.55 250 0.0164 2.67 5 10-yr 7.96 0.70
5 1.68 0.39 1.29 0.45 880 0.0135 7.57 10 10-yr 6.36 4.81
6 2.28 0.70 1.58 0.50 1750 0.0105 14.15 15 10-yr 5.36 6.11
7 2.47 0.76 1.71 0.50 2000 0.0116 15.13 15 10-yr 5.36 6.62
8 3.77 1.45 2.32 0.55 2150 0.0110 16.28 15 10-yr 5.36 11.11
9 1.24 0.48 0.76 0.55 1550 0.0099 13.17 15 10-yr 5.36 3.66
10 0.95 0.37 0.58 0.55 1300 0.0082 12.42 10 10-yr 6.36 3.32
11 0.36 0.14 0.22 0.55 430 0.0098 4.94 5 10-yr 7.96 1.58
12 5.47 0.84 4.63 0.40 1050 0.0140 8.55 10 10-yr 6.36 13.92
13 0.28 0.11 0.17 0.55 400 0.0108 4.50 5 10-yr 7.96 1.23
14 0.00 0.00 #DIV/0! N/A N/A 10-yr #DIV/0! #DIV/0!
15 0.00 0.00 #DIV/0! N/A N/A 10-yr #DIV/0! #DIV/0!
16 0.00 0.00 #DIV/0! N/A N/A 10-yr #DIV/0! #DIV/0!
17 0.00 0.00 #DIV/0! N/A N/A 10-yr #DIV/0! #DIV/0!
18 0.00 0.00 #DIV/0! N/A N/A 10-yr #DIV/0! #DIV/0!
19 0.00 0.00 #DIV/0! N/A N/A 10-yr #DIV/0! #DIV/0!
20 0.00 0.00 #DIV/0! N/A N/A 10-yr #DIV/0! #DIV/0!
21 0.00 0.00 #DIV/0! N/A N/A 10-yr #DIV/0! #DIV/0!
22 0.00 0.00 #DIV/0! N/A N/A 10-yr #DIV/0! #DIV/0!
23 0.00 0.00 #DIV/0! N/A N/A 10-yr #DIV/0! #DIV/0!
24 0.00 0.00 #DIV/0! N/A N/A 10-yr #DIV/0! #DIV/0!
25 0.00 0.00 #DIV/0! N/A N/A 10-yr #DIV/0! #DIV/0!