SW6230501_Design Calculations_20230705

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
1924-ILA'S WAY SUBDIVISION
Rainfall Intensity
Storm Event
5-min 10-min 15-min 30-min
10-yr 7.88 6.31 5.32 3.85
25-yr 8.80 7.01 5.92 4.38
50-yr 9.48 7.55 6.37 4.80
100-yr 10.10 8.05 6.78 5.19
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 (in/hr)
L(ft) n s Toy, L(ft) S Tch
1 2.82 0.43 2.39 0.40 n/a 1450.0 0.010 12.48 12.48 10 10-yr 6.31 7.12
2 0.52 0.12 0.40 0.45 n/a 740.0 0.010 7.44 7.44 5 10-yr 7.88 1.84
3 13.95 1.07 12.88 0.35 n/a 975.0 0.008 10.02 10.02 10 10-yr 6.31 30.81
4 11.17 0.86 10.31 0.35 n/a 825.0 0.009 8.42 8.42 10 10-yr 6.31 24.67
5 0.24 0.06 0.18 0.45 n/a 325.0 0.011 3.80 3.80 5 10-yr 7.88 0.85
6 0.97 0.22 0.75 0.45 n/a 430.0 0.010 4.90 4.90 5 10-yr 7.88 3.44
7 0.61 0.14 0.47 0.45 n/a 285.0 0.013 3.22 3.22 5 10-yr 7.88 2.16
8 1.09 0.25 0.84 0.45 n/a 1450.0 0.010 12.48 12.48 10 10-yr 6.31 3.10
printed:7/5/2023 11:38 AM Page 1 of 1