952
Refutation of objection (1).
No foreshore worthy of
notice.
Proposed reclamation rendering formation of foreshore impossible.
Course of objection
said to be
made by foreshore.
Objection (3).
Caused by large rain-
water drains.
Jervois Street
and Bonham
Strand drains
described.
Mr. Chadwick's description of
Bonham Strand drains.
Inability to see
cause of
objection.
Objection (3). No ventilution
no reason for
not using
existing
Sewers,
Mr. Chadwick
on absence of ventilation.
Ventilation to main Sewers only by shafts.
Sir Robert Rawlinson on ventilation.
Sir Robert Rawlinson en
necessity for Alap valves.
THE HONGKONG GOVERNMENT GAZETTE, 27TH SEPTEMBER, 1890.
With reference to objection 1, I am unwilling to admit that there is any foreshore worthy of mention from Kennedy Town to the City Hall. The amount of silt that is brought down from the hill sides by the large main drains, being chiefly dispersed by the action of the waves and of the tidal current, the balance having been easily removed by the use of one small "Priestman" dredger.
The construction of the proposed reclamation would render the formation of any new foreshore absolutely impossible, owing to the depth of water.
;
In my opinion, the reasons of the objection are:-That the outfalls are not constructed in a suitable manner, no attempt being made to convey the dry weather or normal flow, which is practically sewage, into deep water and that the large number of the floating population, constantly near the Praya wall, cause a large amount of focal matter and garbage to be deposited there. Also, that there is an utter absence of ventilation of the sewers, and defective connection of houses, rendering the sewage matter offensive.
I fail to see, as inferred by Mr. COOPER, that any state of the numerous outlets along the Praya is a reason why the existing sewers should not be used for the conveyance of sewage.
With reference to objection 2. The sewers mentioned are, no doubt, chiefly the large rain water drains, shewn in blue lines on Plate 1, (these I in no case propose to use for sewage). There are, I am aware, some large drains which, owing to the unsuitable course taken necessitating flat gradients, should be diverted and altered.
I would mention, as an instance, the drains in Jervois Street and Bonham Strand. Instead of conveying the drainage of the district by the most direct way into the harbour, the sewers run nearly parallel with the Praya, discharging at Possession Point. As this district is low lying, the sewers are nearly level, and cause great trouble from silting up. I have mentioned, that I consider exactly similar trouble will be experienced with Mr. COOPER's proposed intercepting sewers of flat gradients.
Mr. CHADWICK mentions the sewers in this district in the following terms :-
“Much inconvenience and expense is caused by the necessity for cleaning out periodically the portions of "the sewers where they cross the low districts about Bonham Strand.”
I fail to see why, even granted that there be considerable deposits during the dry season in the large sized sewers of the lower levels, that this is a reason for not using the bulk of the sewers, already constructed, for the conveyance of sewage.
With reference to objection 3. Mr. COOPER alleges, as a reason for not using the existing sewers, that no efficient means of "ventilation exists." This is obviously no reason for not so altering the present sewers, as the cost of making ventilators cannot be so expensive as the construction of new sewers and ventilators.
The statement, that no efficient means of ventilation exists, is supported by Mr. CHADWICK in the follow- ing words, which naturally apply to the date of his report.
"There are no special ventilator openings either inlet or outlet, nor does the necessity for ventilation appear "to have been recognized. The drains, which receive the water from the ravines above the town, have open "outlets at their upper ends or intakes, and so they are to some extent ventilated. Where the drains do not run up the hill sides there is no proper ventilation. For instance, the drain along Old Bailey Street terminating in "the Caine Road. In one instance, that in Peel Street, the natural ventilation of the sewer has been prevented "purposely by the construction of a trap at the top, thus the uprising sewer gas has no means of escape except "by untrapped house drains and gully holes.”
The only attempt at ventilation, made up to the present date, are the few shafts built within the last year at the upper ends of the main drains, and it requires no argument to show, that these only ventilate a very little distance, and the open ends of the drains as before, were practically equally efficient, the only advantage gained by the shafts being the very small difference in the density of the gases for the additional height. These shafts, as I stated in my evidence before the Fever Commission, cannot ventilate any of the side junctions to the main drains, as the gases would then be called upon to descend the side branches, and ascend the main drains.
The opinion of Sir ROBERT RAWLINSON is, that :-
"Sewers formed along steep gradients therefore require to have more care bestowed on the means of venti- "lation than other sewers laid along flat districts to prevent the dangerous accumulation of sewage gases in the "upper districts. Ordinary main sewer ventilation should be provided in all cases at intervals not greater than “100 yards."
The ends of sewers and drains at their lowest outlets must be so protected that the wind cannot blow in "and force any sewage gasos back to the streets and houses. Flap valves or other contrivances may be provided
to cover and protect outlet ends of sewers and drains and so prevent the wind from blowing in."