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71. The average daily demand on the mainland amounted
to approximately 11 million gallons in 1939, the annual rate
of increase since the year 1935 having averaged about 1
million gallons per diem.
72. The function of a service reservoir is twofold:-
(1) to provide a reserve of water in case of emergencies such as fires or an accident to the main aqueduct; (2) to
provide storage of filtered water which can be draw upon when
the demand exceeds the rate at which the water can be supplied
to the filters and filtered.
73. The provision of this storage has a most important
effect, as without it, the capacity of the filters and dimension of the aqueduct would have to be greatly increased so as to meet
the maximum demand.
74. Mr. Woodward in his Report already referred to, states
that the usual provision would amount to about two days' storage
of the average annual demand and we agree that this figure
should be realised.
75. The provision of a total of 46.6 million gallons
storage would be sufficient for an average daily supply of
23.3 million gallons, which would be reached before many years
have passed if the rate of increase in demand since 1935
continues.
Existing Supplies on the Mainland.
Sources of Supply.
76. The supply of Kowloon is divided into two zones,
a high level zone, which takes water from the Jubilee, Reception and Shek-lai-pui Reservoirs, having a gross capacity
of a little over 3,150 million gallons, and a low level zone,
supplied by the Kowloon and Byewash Reservoirs with a gross
capacity of about 540 million gallons, the estimated maintainable yield of the high level sources being about 13.5 million gallons
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