CO129-322 - Acting Governor May - 1904 [1-5] — Page 391

COPY.

The Honourable

Enclosure 3.

C.O.

14069

3891

Hongkong, 7th March, 1904

W. Chatham,

Director of Public Works.

Dear Sir,

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Kowloon Waterworks Gravitation Scheme.

in reply to your letter No. 218 of 25th.

February, 1904, we consider the dam for Kowloon Waterworks may

with safety be raised 5 feet and we estimate the cost of so doing

including the cost of raising the road and Eyewash Dam at $65,000.

We limit the proposed raising to 5 feet on

account of the nature of the hillsides at the south end of the

Dam, at this place the dam, instead of running into the sides of

a valley runs into the end of a ridge and consequently it is most

probable that the rock slopes away as shown on the section here-

with from both sides of the dam. The natural ground here does not

come up to the section of an ordinary earthen dam and it is bad

ground, being liable to siips when cut as flat as 1 to 1, and

cannot therefore be trusted to act as an earthen dan, especially

considering the probable slope of the rock on which it lies. Con-

sequently any raising of the dam necessitates the full section of

the dam being carried further into the hillside before it can be

reduced to the section of an ordinary stopwater trench supported

by the natural ground forming an earthen dam.

he find the additional 5 feet will give 50

million gallons additional storage.

There is no absolute proportion which it is

necessary to observe between the storage capacity of a reservoir

and its drainage area. Speaking generally 1 Square Mile will give 1,000,000 gallons a day and requires about 200,000,000 gallons

storage.