In the water supply system shown in Fig. 1, water is pumped from the ground reservoir to the Vi1lage ABCD (elevation 120.00 m) through the water main PA. The value of C for all pipes is 100. A water meter located on pipe DC indicates a flow of 20 L/s. The following network data are provided:
Pipe d, mm L, m
PA 500 10,000
AB 250 500
AC 200 700
AD 200 500
BC 250 1,000
CD 150 1,000
Fig. 1 Water System for Problem 1
(a) Determine the flow in each pipe as well as the flow delivered to point C (Qc).
(b) Calculate the pumping head, if the residual pressure at point C is not to be less than 150 kPa
2. The water supply system shown in Fig. 2 is designed to serve a small town ABDCA. The flow from the reservoir is delivered to the town by gravity through the 400 mm main. All pipes have a Hazen-Williams C of 100.
(i) Determine the flowrate in each pipe.
(ii) What is the flow in the mains from the reservoir to ABCD?
3. A circular gate 4m in diameter is to be placed on the incline of a reservoir as shown in Fig. 3. TThe gate rotates about a shaft installed on an axis parallel to the water surface and through the diameter (see figure) and is prevented from opening by a stopper. Given that the free surface is 10m above the shaft, (i) what is the magnitude and location of the resultant force by the water acting on the circular gate? (ii) what is the moment about the shaft?