HomeMy WebLinkAboutSW6190701_Calcs_(Ditch)_201911061360-The Farms Subdivision
Ditch Calculations
Overland flow time (To) calculated by Kerby
Method
Ditch flow time (T,h) calculated by Kirpich
Method
Ditch #1
Road A Sta. 0+00 to END right
Tc = 28.4 min + 4.8 min = 33.2 min, use 30 min
Overland Flow:
403 LF, 0.7%, n=0.4, T,,= 28.4 min
Ditch Flow:
294 LF, 0.5%, Tch = 4.8 min
DA = 6.57 ac
C = 0.40
1 = 3.86 in/hr
Q = 10.10 cfs
n;+_L. u,
Road A Sta. 0+00 to END left
Tc = 12.9 min, use 15 min
Ditch Flow:
1070 LF, 0.5%, Tch = 12.9 min
DA = 1.65 ac
C = 0.45
1 = 5.33 in/hr
Q = 3.96 cfs
Ditch #3
Road B Sta. 0+00 to Sta. 1+50 right
Tc = 26.8 min + 2.5 min = 29.3 min, use 30 min
Overland Flow:
330 LF, 0.6%, n=0.4, T,,v = 26.8 min
Ditch Flow:
128 LF, 0.5%, Tch = 2.5 min
DA = 2.87 ac
C = 0.45
1 = 3.86 in/hr
Q = 4.98 cfs
Ditch #4
Road B Sta. 2+00 to Sta. 9+00 right
Tc = 59.1 min + 4.0 min = 63.1 min, use 60 min
Overland Flow:
1270 LF, 0.3%, n=0.4, T,,= 59.1 min
Ditch Flow:
237 LF, 0.5%, Tch = 4.0 min
DA = 9.57 ac
C = 0.40
1 = 2.52 in/hr
Q = 9.65 cfs
Ditch #5
Road B Sta. 2+00 to Sta. 9+00 left
Tc = 9.2 min, use 10 min
Ditch Flow:
687 LF, 0.5%, Tch = 9.2 min
DA=0.52ac
C = 0.50
1 = 6.32 in/hr
Q = 1.64 cfs
Ditch #6
Road B Sta. 0+00 to Sta. 2+00 left
Tc = 59.1 min + 6.9 min = 66 min, use 60 min
Overland Flow:
1270 LF, 0.3%, n=0.4, T,,= 59.1 min
Ditch Flow:
473 LF, 0.5%, Tch = 6.9 min
DA = 19.70 ac
C = 0.40
1 = 2.52 in/hr
Q = 19.9 cfs
Ditch #7
Tc= 59.1 min + 8.9 min = 68 min, use 60 min
Overland Flow:
1270 LF, 0.3%, n=0.4, T,,= 59.1 min
Ditch Flow:
665 LF, 0.5%, Tch = 8.9 min
DA = 22.57 ac
C = 0.40
1 = 2.52 in/hr
Q=22.8cfs
Ditch #8
Road B Sta. 9+00 to Sta. 11+50 right
Tc= 36.2 min +4.1 min = 40.3 min, use 45 min
Overland Flow:
545 LF, 0.45%, n=0.4, T,,= 36.2 min
Ditch Flow:
245 LF, 0.5%, Tc = 4.1 min
DA = 1.53 ac
C = 0.45
1 = 3.19 in/hr
Q = 2.20 cfs
Ditch #9
Road B Sta. 9+00 to Sta. 11+50 left
Tc = 4.3 min, use 5 min
Ditch Flow:
254 LF, 0.5%, Tch = 4.3 min
DA = 0.19 ac
C = 0.50
I = 7.91 in/hr
Q = 0.75 cfs
Ditch #10
Road B Sta. 11+50 to END right
Tc = 40.6 min, use 45 min
Overland Flow:
805 LF, 0.6%, n=0.4, T,,= 40.6 min
DA = 3.79 ac
C = 0.45
1 = 3.19 in/hr
Q = 5.44 cfs
Ditch #11
Road B Sta. 11+50 to END left
Tc = 35.4 min + 8.1 min = 43.5 min, use 45 min
Overland Flow:
597 LF, 0.6%, n=0.4, T,,= 35.4 min
Ditch Flow:
588 LF, 0.5%, Tch = 8.1 min
DA = 1.30 ac
C = 0.40
1 = 3.19 in/hr
Q = 1.66 cfs
Ditch #12
Tc = 50.0 min + 7.6 min = 57.6 min, use 60 min
Overland Flow:
1145 LF, 0.5%, n=0.4, T,,v = 50.0 min
Ditch Flow:
536 LF, 0.5%, Tch = 7.6 min
DA = 10.55 ac
C = 0.40
1 = 2.52 in/hr
Q = 10.63 cfs