Page 195 - Water Engineering Hydraulics, Distribution and Treatment

Ground level at elevated water tank (C) = 612.20 m.
5.7
station is operating at a flow capacity of 125 L/s against a total
Water level in tank (C) = 30 m above ground.
dynamic head of 50 m. Determine the maximum depth of water that
can be stored in the elevated reservoir.
The lift pumps provide flow at a discharge pressure of 550 kPa.
Elevation of water level in underground tank = 500 m.
Compute the discharge Q in L/s at withdrawal point B for the
Elevation of bottom of elevated reservoir = 520 m.
following conditions:
C for all pipes = 100.
(a) If the residual pressure at point B is 200 kPa
(b) If water is neither flowing to, nor from, the elevated storage
Q = 40 L/s
Q = 50 L/s
tank
Pumps
Branch
Elevated reservoir
Branch
pipe
pipe
C
B
Ground In the water supply system shown in Fig. 5.31, the pumping The value of C for all pipes is 100. Problems/Questions 173
Elevated
water P d = 300 mm d = 250 mm
reservoir d = 400 mm d = 300 mm d = 250 mm P tank
L = 2,000 m L = 1,500 m L = 1,000 m L = 1,500 m Q L = 900 m
Water
Figure 5.31 Water system for Problem 5.7. A withdrawal
Ground
reservoir
5.8 In the water supply system shown in Fig. 5.32, water flows
by gravity from reservoir A to points C and D as well as to reservoir Figure 5.33 Water system for Problem 5.9.
E. The elevations of known points are as follows:
5.10 The water supply system shown in Fig. 5.34 is designed to
Water level A = 650.00 m. deliver water from the pumping station to city ABC. The water level
in the wet well at the pumping station is at 1,000 ft.
Elevation B = 590.00 m.
The head delivered by the pumps to the water is 100 ft. The
Elevation C = 550.00 m.
value of C for all pipes is 100. Assume the following elevations:
Elevation D = 570.00 m. A. 900.00 ft.
C B. 9l5.00 ft.
d = 300 mm
L = 3,640 m C. 910.00 ft.
Water A B D
reservoir d = 300 mm (a) Determine the required diameter of main PA, if the pressure at
d AB
L = 10,000 m L = 2,500 m point A is not allowed to drop below 52 psi.
E Water
d = 400 mm reservoir (b) Determine the required diameter of pipe BC, if the maximum
L = 11,760 allowed head loss in the network ABC is 3 ft∕1,000 ft.
Figure 5.32 Water system for Problem 5.8. (c) Calculate the actual residual pressures at points A, B, and C.
The measured residual pressures are as follows: d = 18 in.
L = 5,000 ft
Point B = 300 kPa.
C
Point C = 500 kPa. Pumping P A 2,900 gpm
station
d PA
L = 10,000 ft
The known flows are as follows: d = 14 in. d BC
L = 2,500 ft L = 2,500 ft
1,150 gpm B
Pipe BD = 30 L∕s.
Pipe BE = 75 L∕s.
C for all pipes = 100.
750 gpm
(a) Calculate the flow in line BC. Figure 5.34 Water system for Problem 5.10. Conversion factors:
(b) Find the residual pressure at point D. 1 gpm = 3.785 L/min; 1 ft = 0.3048 m;1 in. = 25.4mm.
(c) Compute the maximum water level in reservoir E.
5.11 Water is pumped from ground reservoir A to the elevated
(d) Determine the required diameter for pipe AB.
reservoir G through the network of pipes shown in Fig. 5.35.
The following data are given:
5.9 A water supply system consists of a ground reservoir with All pipes have the same diameter = 300 mm.
lift pumps (A), elevated storage (C), a withdrawal point (B), and C for all pipes = 100.
equivalent pipelines as given in the plan view in Fig. 5.33. Assume Water level in ground reservoir = 500 m.
the following elevations: Water flow rate = 80 L∕s.
Pump operating head = 70 m.
Water level in ground reservoir (A) = 600.00 m. (a) Calculate the maximum water level in the elevated reservoir
Ground level at withdrawal point (B) = 609.10 m. when valves E and F are closed.