QUESTION 4
(a) What does the term hydraulic gradient mean?
(1 mark)

(b) On Fig. 1 below, draw a line showing the hydraulic gradient line if outlet C is open.
DRAW OFF AT LOWEST POINT
Fig 1.

PLEASE SEE PDF FOR DIAGRAM

(1 mark)

(c)  For Figure 1 explain what happens to the flow of water at the intermediate draw-off points, labelled
A and B, when the outlet at the lowest point C is flowing at full volume.
(2 marks)

(d)  State the most frequent cause of airlocks in low pressure water supply systems, and explain how
airlocks occur.
(3 marks)

(e)  A pipeline is supplied from a storage tank in a low pressure system. It is not possible to alter the
pressure of the supply or the gradient of the pipe. Describe how an air lock in the pipeline can be
permanently eliminated.
(1 mark)
Total 8 marks


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