96
MINUTE BY
MR. A. B. PURVES, M.INST.C.E.
Hon. D.P.W.,
I have little to add to the very full report prepared by Mr. Woodward: the figures given are indisputable and generally I agree with the report.
The consumption recorded during the past few months, with a constant supply, is extraordinarily high and has entirely upset all previous estimates.
Mr. Woodward's estimates of future requirements cannot be regarded as high and if consumption continues to increase as forecasted, the present works will soon be inadequate to maintain a constant supply.
Filtration and distribution difficulties are increasing rapidly and it was just possible to avoid the introduction of restrictions last August when consumptions of 17.37 and 10.22 M.G.P.D. were recorded on the island and mainland respectively over a period of a fortnight.
As regards storage, the present position is relatively similar to that in 1920, when 2 years previously the island storage had been trebled by the completion of the Tytam Tuk Reservoir.
It was then thought and stated that Hong Kong water troubles were over for many years, but from 1922-1936, without a single exception, annual restriction of the island supply had to be imposed.
From 1920-1935 inclusive, approx. $20,000,000 had been spent on new Water Works, and already, despite the newly completed Jubilee Reservoir, the safety margin between resources and requirements for a constant supply is very small and by next year will have disappeared.
The programme of work outlined in Appendix VI is a formidable one and re- presents an outlay of probably $5,000,000. The time required to complete these works will depend on the staff provided. The present staff of the Water Works Construction Sub-department is quite inadequate to carry out this programme within a reasonable time and could deal only with the items of greatest urgency.
The following are the principal difficulties pertaining to the island supply which require immediate consideration.
1. Deficiency in raw water resources.
2. Increasing and safeguarding the delivery from the mainland to the island. 3. Lack of facilities on the island for taking fuller use of mainland water. 4. Additional filtration plant.
The deficiency in raw water resources can be met, temporarily, by constructing the Tai Mo Shan and other Catchwaters draining into the Shing Mun Valley, as shown in Appendix I and referred to in Paras. 32 and 33 of Report.
It is estimated that these Catchwaters, dealing with a total drainage area of 3888 acres, would increase the Shing Mun resources by 5 M.G.P.D.
As however about 4 years would be required to complete these works, the position on completion would be little better, relatively, than at present if the estimates of future consumption are borne out.
Further increases of the Shing Mun resources may be found economically possible, but at present it is considered that the works shewn on Appendix I re- present the final development of the Scheme.
It is accepted in Great Britain that water works resources should maintain a 5 years lead over requirements. If this practice is to be applied in Hong Kong, and there seems every reason why it should be, the only solution is to seek fresh sources of supply in the New Territories.