No. 89.
20
HONGKONG.
REPORT ON THE SEPARATE SYSTEM OF MAIN-DRAINAGE.
Presented to the Legislative Council, by Command of His Excellency the Governor.
PUBLIC WORKS DEPARTMENT,
HONGKONG, 24th August, 1888.
SIR,
I have the honour to transmit you the enclosed preliminary Report of Mr. F. A. COOPER, on the Separate System of main drainage for the city of Victoria and to recommend his propositions to the favourable consideration of His Excellency the Governor,
2. The adoption of the Separate System will be in harmony with the drainage provisions of the new Public Health Ordinance.
3. The main features of the Project are four, viz.:—
(i.) The dissociation of the sewage of houses from storm-waters.
(i.) The rapid conveyance of the town-sewage to the sea and its innocuous disposal in the tidal current by means of separate glazed stoneware drain-pipes of a bore comparatively small because of the elimination of storm-waters.
(iii.) The admission of a limited proportion of rain-fall into these proposed
foul water drains; and
(iv.) The escape of storm-waters and sub-soil drainage into the sea as heretofore through the present main drains of the city which remain undisturbed.
4. The dissociation of house-sewage from storm-waters will so greatly reduce the volume of foul water to be dealt with, and will make that volume so manageable as to enable small diameters to be used for the principal arteries, and due to this circumstance the project will be feasible at an outlay that is moderate compared with the relative expense that would attend the construction of the same length of main sewers under the Combined System which requires-in consequence of our heavy rain-falls—that all channels be of an unduly large and costly size. The estimated cost of the four proposed new foul water mains comprised in this scheme, together with their branches and all contingent works amounts to $230,000, but as the eastern district of Victoria is found to be nearly on a dead level and as it is found impossible to give the proposed eastern main a gradient or inclination sufficient to induce a self-cleansing velocity, it will be necessary eventually to dispose of the
The Honourable FREDERICK STEWART, LL.D.,
Colonial Secretary.