Sessional_Paper_1887-1888 — Page 327

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There are few water closets in the city their construction being prohibited by law. The system generally adopted for removing the excreta being the pail system as described in Mr. CHADWICK'S Report. I certainly agree with Mr. CHADWICK that if a sufficient water supply can be obtained the more general adoption especially in Hotels, Clubs and large mercantile and other offices, of water closets would be advisable on sanitary grounds.

There is practically no sub-soil drainage in the city except in the Wongnei- chung Valley where such drainage has been carried out during the last six months.

PROPOSED WORKS.

After careful consideration of the whole of the foregoing facts and a close study of the locality I am of opinion that the ends of efficiency and economy will be best met by:-

(1.) the construction of a new system of pipe sewers admitting only a limited quantity of surface-water and by adopting out-falls for such a system at suitable points cast and west of the city.

(2.) the utilization of the existing drains for conveying the natural streams through the city and for carrying off surface and sub-soil

waters.

Though the sub-soil drainage of malarial soils is a matter of great importance to the Public Health, this will be impracticable in the lower parts of the city at present unless such sub-soil drains are connected with the sewers, an expedient that would be attended with serious risk for it would convert such sub-soil drains into channels for the escape of sewer air through the sub-soil into the houses them- selves. Owing to the long periods of drought or of limited rain-fall and to the steep declivity of the greater part of the drainage areas, the flow of water in sub-soil drains will always be very variable and will no doubt very often be nil. In the latter case drain traps attached to sub-soil drains will prove ineffective and sewer air will freely course through such drains and issue through the interstices provided for the escape of sub-soil water.

Further, in the case of any stoppage occurring in a foul water sewer with which sub-soil drains happened to be in communication, sewage might back into the sub-soil drains and escape through the joints as just described. These objections. will be got rid of if all foul waters are diverted from the existing drains of the town into special channels of their own sub-soil drainage then becomes possible and may be led without risk into the present existing drains.

I will now briefly describe the new Separate System of sewers proposed. On looking at the plans it will be seen the city is naturally divided into four drainage districts. Three of these districts are situated to the west of the Albany Nullah, and one to the east. There are thus, four proposed main intercepting sewers which for the convenience of reference I will allude to as numbers 1, 2, 3 and 4, draining districts Nos. 1, 2, 3 and 4 respectively as marked on the accompanying plan.

Main No. 1 providing for the drainage of district No. 1 (coloured red on plan sheet No. 1,) will commence in Caine Road opposite Castle Road where it receives the sewage from Seymour Road, Castle Steps and Castle Road, it then takes a westerly course along the Caine Road, Bonham Road, Hill Road and Queen's Road West receiving the sewerage from Robinson and Richmond Roads, and ulti- mately discharging into the harbour at Belcher's Point.

The area of this district is 160 acres, and it is only thinly built over, but in order to allow for future extensions the sizes of the sewers have been calculated to discharge per 24 hours as much as 11⁄2 inches of rain-fall over the whole area.

Main No. 2 providing for the sewerage of District No. 2 (coloured brown on plan sheet No. 1,) will commence in Queen's Road Central opposite Pottinger Street and takes a westerly course along Queen's Road receiving the sewerage from those portions of the Chung-wan, Tai-ping-shan and Sai-ying-pun districts which are situated south of the Queen's Road. On reaching Centre Street this main will take a northerly course down Centre Street, and arriving at the Praya will turn again to the west and follow the line of the Praya where it will receive the sewage of a portion of the Shek-tong-tsui District and ultimately discharge into the harbour at the proposed out-fall at Belcher's Point.