SW6240201_Design Calculations (Flow)_20240213

4D Site Solutions, Inc.
DITCH CALCULATIONS
NOTE: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
2005-Langdon Preserve Subdivision
Rainfall Intensity
Storm Event
5-min 10-min 15-min 30-min Runoff Coeff.
10-yr 7.61 6.09 5.14 3.72 Impervious 0.95
25-yr 8.52 6.79 5.73 4.25 Grassed 0.30
50-yr 9.16 7.30 6.16 4.64
100-yr 9.76 7.76 6.54 5.01
Tc
Drainage Impervious Grassed Storm Rainfall
Ditch No. C Kerby Kirpich Intensity Q(cfs)
Area(ac) Area(ac) Area(ac) Event(yr)
Total Tc Tc Used (m/hr)
L(ft) n s T0V L(ft) S Tc1,
1 1.33 0.51 0.82 0.55 n/a 540.0 0.007 6.75 6.75 5 10-yr 7.61 5.57
2 0.13 0.04 0.09 0.50 n/a 180.0 0.010 2.50 2.50 5 10-yr 7.61 0.49
3 0.13 0.04 0.09 0.50 n/a 180.0 0.010 2.50 2.50 5 10-yr 7.61 0.49
4 0.91 0.21 0.70 0.45 n/a 315.0 0.006 4.59 4.59 5 10-yr 7.61 3.13
5 0.59 0.14 0.45 0.45 n/a 340.0 0.012 3.84 3.84 5 10-yr 7.61 2.00
6 0.78 0.18 0.60 0.45 n/a 420.0 0.028 3.22 3.22 5 10-yr 7.61 2.67
7 2.68 0.62 2.06 0.45 n/a 690.0 0.036 4.31 4.31 5 10-yr 7.61 9.16
8 4.25 0.98 3.27 0.45 n/a 950.0 0.029 6.00 6.00 5 10-yr 7.61 14.57
9 5.12 1.18 3.94 0.45 n/a 1150.0 0.027 7.09 7.09 5 10-yr 7.61 17.55
10 5.16 1.19 3.97 0.45 n/a 1200.0 0.027 7.36 7.36 5 10-yr 7.61 17.66
11 5.19 1.20 3.99 0.45 n/a 1300.0 0.035 7.09 7.09 5 10-yr 7.61 17.78
12 5.19 1.20 3.99 0.45 n/a 1300.0 0.035 7.09 7.09 5 10-yr 7.61 17.78
13 1.22 0.28 0.94 0.45 n/a 410.0 0.026 3.27 3.27 5 10-yr 7.61 4.19
14 0.32 0.10 0.22 0.50 n/a 370.0 0.020 3.34 3.34 5 10-yr 7.61 1.20
15 0.80 0.25 0.56 0.50 n/a 620.0 0.031 4.22 4.22 5 10-yr 7.61 3.06
16 0.31 0.10 0.21 0.50 n/a 315.0 0.020 2.95 2.95 5 10-yr 7.61 1.18
17 0.50 0.15 0.35 0.50 n/a 420.0 0.025 3.38 3.38 5 10-yr 7.61 1.91
18 0.72 0.22 0.50 0.50 n/a 590.0 0.022 4.64 4.64 5 10-yr 7.61 2.72
19 1.12 0.34 0.77 0.50 n/a 820.0 0.029 5.38 5.38 5 10-yr 7.61 4.26
20 0.18 0.07 0.11 0.55 n/a 210.0 0.049 1.53 1.53 5 10-yr 7.61 0.75
21 1.32 0.40 0.91 0.50 n/a 845.0 0.030 5.43 5.43 5 10-yr 7.61 5.00
22 2.01 0.62 1.39 0.50 n/a 1100.0 0.025 7.09 7.09 5 10-yr 7.61 7.65
23 2.42 0.56 1.86 0.45 n/a 730.0 0.016 6.18 6.18 5 10-yr 7.61 8.29
printed:2/13/2024 7:28 AM Page 1 of 1