Advanced Waterworks Mathematics, 2019a

Q (cfs) 3.18 cfs
A (ft ) = = = 1.17777 ft = 1.2 ft
V (ft/sec) 2.7 fps
2 2 2
Area = 0.785
D
2
Area 1.2 ft
D = = = 1.5286624 ft
0.785 0.785
2
2 2
2 2
D = 1.5286624 ft
D = 1.236390 ft
12 in
1 ft
= 14.8366 in = 15 in
5. A 20-mile aqueduct flows 22,200 AFY at an average velocity of 0.32 fps. If the distance
across the top is 20 feet and the depth is 6 feet, what is the distance across the bottom?
Q =
3
22,200 AF 325,851 gal 1 year 1 day 1 hr 1 min 1 ft
year 1 AF 365 day 24 hr 60 min 60 sec 7.48 gal
Q (cfs) 30.7 cfs
A (ft ) = = = 95.9375 ft
V (ft/sec) 0.32 fps
2 2
b b
Trapezoid Area =
2
20 ft ? ft
2
1 2
2
96 ft = 6 ft
2
20 ft ? ft 96 ft
= = 16 ft
2 6 ft
20 ft ? ft = (16 ft)(2) = 32 ft
H
= 30.6664728 cfs
? ft = 32 ft - 20 ft = 12 ft
299 | A dvanced Waterworks Mathematics