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The filtering material is fine sand varying from 2' 0" to 2' 4" in depth, overlying
fine and coarse stone.
The beds are built on the ridge and furrow system and discharge the filtered water into a covered Reservoir capable of holding about 850,000 gallons, and from which the water is passed into the cast iron pipes which form the distribution system of the City."
THE LIABILITY OF THE CATCHMENT AREA TO CONTAMINATION.
Very different opinions have been expressed as to the suitability or otherwise of this area; among the more important unfavourable opinions may be quoted that of Colonel Bedford, P.M.O., Member of the Sanitary Board who in a minute dated 1st January, 1910, states:
"In spite of arguments to the contrary, I maintain that Pokfulum area stands condemned in the eyes of practical men; and the sooner that steps are taken to extend the other sources of water supply to the Colony, and the closing of this most suspicious one, the better."
The Report of a Select Committee of the Sanitary Board appointed "to enquire into the conditions obtaining with regard to Mount Austin Nullah and the Water Supply collected from that area" 30th April, 1910, contains the following opinion :-
"We are of the opinion that no authority on sanitation could uphold for an instant the classing of a watershed (from which water for drinking purposes is collected) as ideal or under any other heading than dangerous, when the number of possible sources of contamination, the traffic and the number of houses on the area are taken into consideration."
On the other hand, opinions as strongly in favour of the area have been expressed.
The possible sources of pollution in the area are :-
(1) There are 59 European houses with their coolie quarters containing some
hundreds of Chinese in the area.
(2) The system of conservancy is the bucket system.
(3) The area is intersected by several Public Roads along which a consider-
able amount of coolie traffic takes place.
On the other hand, there is practically no cultivated ground in the area and no animals except dogs and perhaps a few deer and birds. Most of the soil is very poor.
Under these circumstances it is imposible to regard the area as in any way ideal,. the casual habits of nightsoil coolies etc. are too well known; on the other hand there is no apparent good reason for condemning the catchment area as long as a careful supervision is kept over it and efficient storage and filtration of the water carried out.
A plan of the area, prepared by Mr. Hollingsworth, is attached from which the details of the area can be seen. *
THE STORAGE OF THE WATER.
It will be noted from Mr. Hollingsworth's account of the Water Works that a considerable amount of the water especially in wet weather is never stored at all, but is led directly on to the filter beds.
There is unfortunately no means of knowing definitely what proportion of the water run on to the filter beds is stored and what is unstored; after long drought practically all the water comes from the Reservoir, and during wet weather most of the water is taken direct without any storage at all.
Between these two extremes a mixture of unknown proportion is apparently used.
* Not printed.
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