THE HONGKONG GOVERNMENT GAZETTE, 27TH SEPTEMBER, 1890.
escape of rain-water. Mr. LEIGH states also that in lieu of only four points of out-fall he would prefer many more and so avoid concentration of sewage inatter at so few as four places. There might be something in this contention if the water in the harbour were stagnant, but as Mr. COOPER's proposed outlets of sewage-delivery are swept by tidal currents, Mr. LEIGH's multiplication of ont-falls does not appear to me to be necessary, but whether necessary or not, the question is disposed of with regard to the Central and Western districts now that we are to have a general reclamation of the foreshore from Murray Pier to West Point; because it is certain that the erection of the new quay wall further out into the harbour along deeper water will tend to im- prove the velocity of the inshore currents and thus promote the more rapid dispersion of the effluent.
In lieu of these inter-
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9. Mr. LEIGH's third and final objection is to the proposed intercepting sewers. cepting sewers Mr. LEIGH recommends the direct consigning into the sea-of the contents of each descending He impugns main-sewer as soon as the latter has been carried down to the Praya level-by the shortest route. the propriety of collecting together the aggregate sewage of several knots or groups of foul-water drains, and contends that this gathering in of converging foul waters into one trunk-pipe running parallel with the shore- line will not work, because the incline will be so flat as to preclude flow and thereby choke the trunk-pipe. In the previous paragraph I have already explained that there will be a self-cleansing velocity, and that as the But trunk-pipe has been designed to be self-cleansing, the block anticipated by Mr. LEIGH will not occur. again here the new Reclamation Scheme which was elaborated subsequently to the Drainage Project will neces- sitate a reconsideration of the latter in that branch of it which relates to the intercepting sewers, and as we shall now have in the central and western town a marine embankment in deep water throughout, I am of opinion that it will be found preferable to adopt the modification set forth in the small alternative plan prepared by Mr. COOPER and dated the 29th of December, 1888, which plan together with a Report from Mr. COOPER in reply Mr. COOPER'S
Report of 29th to Mr. LEIGH's criticisms is now submitted. In the Eastern portion of Victoria where no sea-reclamation is December,
1888, and contemplated the first or original scheme prepared by Mr. COOPER would remain unaltered.
10. All those passages in Mr. LEIGH's letter wherein he urges the increased ventilation of the main sewers in connexion with his Combined Project, are, as stated before, concurred in by Mr. COOPER and myself provided the main sewers are continued in use as foul-water conduits. If sewage liowever is diverted from them into separate glazed stoneware pipe-drains as advocated by us it will obviously be unnecessary to embark in any system of increased ventilation for channels that are destined to carry only rain-water.
The question of the adoption or the rejection of the Separate System must therefore be settled first, and that of the ventila- tion of the present sewers second, and on this point I would like to point out that all the ventilation in the world will be useless so long as each private house-drain connected with such ventilated main continues to remain an elongated cesspool of putrid sewage, without fall or without flow. Mr. COOPER and myself have pre- ferred to advise the reconstruction of defective house-drains as the first remedy and increased ventilation of mains as the second. Mr. LEIGH joins issue with us, and clamours for the increased ventilation of mains while he relegates the removal of the noxious house-drains and their substitution by properly built ones to a second place in the order of importance. To illustrate my point by a simile: Mr. LEIGH brings into the room a dead cat far gone in decomposition and then with his handkerchief to his nose begins to clamour about the defective ventilation of the room. Our reply is a simple cominon-sense reply; we say: "As however wide we may open the door and window to improve the ventilation, the smell will not disappear, your best plan will be to remove the cause of smell first." With regard to defective house-drains however, it may be stated that the Public Health Ordinance, having now made sanitary reform compulsory a marked improvement may be expected within the next few years in the drainage of native tenements, and this together with the ample ventilating facilities shewn in Mr. COOPER's proposed pipe-sewers under the Separate System, will provide the true remedy for the evil odours complained of.
enclosure.
948.]
11. At page 5* of his letter Mr. LEIGH proposes to reserve exclusively for the passage of through-streams [ Gazette, p. from the Mountain side,-all the present drains of a larger size which traverse the Chinese districts. No sewage is to enter these larger main drains, but duplicate sewers are to be built alongside of them for the escape of the local rainfall in the particular district subserved, and for the district sewage combined. This looks to mne very much like the Separate System, and if Mr. LEIGH acknowledges in respect of the larger main-drains the advantage of dissociating foul waters from storm floods, why not extend his support to the lesser drains which are only in one degree less subjected to the same conditions, and at once espouse Mr. COOPER's propositions? But Mr. LEIGH'S proposition of large sized double-barrelled main drains down the same valley lines besides being clumsy and complicated will involve if adopted, an outlay so large as to represent in this particular feature alone, about one quarter of Mr. COOPER's entire estimate of cost, and if to this outlay we add the expense of providing new combined sewers in all those streets which at present do not possess them we shall find that Mr. LEIGH's estimates of cost will exceed those of Mr. CoOPER with the difference that under the carefully elaborated plans of the latter we shall acquire a thoroughly comprehensive