THE HONGKONG GOVERNMENT GAZETTE, 27TH SEPTEMBER, 1890. 973
time that the foundation is uncovered by the tide. To give the necessary sectional area, to the storm-water channels, they should be made wider and shallower than has, hitherto, been usual. To this end also, the covering of the channel will be most conveniently made flat, of concrete supported on iron girders; or iron or steel trough-plates; the concrete forming the road-way.
31. A storm-water channel, on this principle, is now under construction in Jubilee Street, the covering being carried on old rails, returned from Tytam Works. The reconstruction of this channel was undertaken, because the old one ran under the site of the Central Market.
32. It will be well, in order to save expense, to reduce the number of storm-water chanuels, which cross the reclamation, to the minimum, consistent with sufficient discharging-capacity. The construction of the proposed sewers will allow of the abandonment of many of the minor outlets, which now exist along the Praya; and which serve as out-falls, for both sewage and rain-water. The sewage will be intercepted by the proposed sewer, which will have sufficient capacity to carry the rain-water, to the nearest storm-overflow, where it will escape to the storm-water channel.
33. It will be well to keep the cost of altering or reconstructing the storm-water drains separate from that of the sewerage-system proper. Minor alterations and repairs may be, legitimately, charged to the usual vote-Main Drainage and Sanitary; whilst alterations, on account of the new Praya Reclamation, will be properly charged to that undertaking.
34. Inasmuch as dirty water often thrown into the side-channels of the streets; and the rain-water which flows down them, at the commencement of showers, is little better than sewage, trapped gulleys should be provided in them, in connec- tion with the sewers, in addition to the ordinary gulleys, communicating with the storm-water channels.
35. When the proposed works are complete, there will be no objection to the use of water-closets, by those who desire to do so: provided always, that proper appliances for flushing are used in connection with them. The introduction of water- closets will be a great boon to the European community; for, as the prosperity of the community increases, there will be more and more difficulty in having hand-removal properly carried out.
36. I do not contemplate the introduction of the water-carriage system, universally, as I do not consider that the popu- lation generally is ready for it; notwithstanding its superiority to any other. In Hongkong, moreover, the facilities for complete and efficient hand-removal, which exist in China, do not exist; as there is no extensive area of agricultural land, in the vicinity of the town. If water-closets are largely introduced in European houses, their use may spread to the Chinese also. If such a tendency does shew itself, it should not be resisted.
37. Were this the case, complete diversion of the sewage might perhaps become desirable. In the preparation of the present project, regard has been had to the possibility of meeting such a demand. The proposed arrangements are such that this could be effected, without material alteration of the general project.
38. It is unnecessary to go into the details of the arrangements, for complete interception. The most convenient and economical means of doing this will be to lay a cast-iron pipe along Queen's Road and Praya, working under pressure; with branches, carried up the side-streets, to intercept the sewage, at sufficient elevation to carry it, by gravity, to the desired out- fall. The sewage of the district below, this elevation, must be pumped into this main. The pumping could be effected by hydraulic motors, established at the proposed out-falls, worked by water from the water-works, or by water under still higher pressure, supplied from some central pumping station, and which would also be available for working Hydraulic cranes.
39. The estimated cost of the sewerage of the district, now under consideration, is as follows :-
31,454 yards of sewer varying from 21′ to 6′′ diameter principally 9", Man-holes, ventilators, street gulleys; and syphons for crossing the storm-water channels, .. Flushing tanks, &c.,
Out-falls,.
Total,
.$105,094.65
32,012.00
5,000.00
3,000.00
$145,106.65
40. This sum does not include the cost of making connections to house-drains; as this is, for the present, done by the house-holders. It is most desirable that the actual connection should be made, and the trap fixed, by the Drainage Depart- The discussion of this question, however, involves the consideration of the whole subject of House-drainage, which is so important that it will be dealt with in a separate report.
ment.
41. The works described in this report may be completed in three years, from date of order to commence. Pipes, etc. are in stock, to the value of about $50,000, which will be available for the work.
To
The Honourable W. M. DEANE, C.M.G.,
Acting Colonial Secretary.
I have the honour to be,
Sir,
Your obedient Servant,
OSBERT CHADWICK.