DRAINAGE SCHEME.

Auckland Star, Volume LXVI, Issue 251, 23 October 1935, Page 8

DRAINAGE SCHEME.

NORTHERN AREA.

I MR. H. H. WATKINS' REPORT. ST. LEONARD'S OUTFALL. Aspects of the comprehensive drainage scheme as it affects the North Shore were dealt with in a report presented to the Nortbcote Borough Council last evening by Mr. H. H. Watkins, engineersecretary to the Auckland and Suburban I Drainage Board. Following the reading j of the report the Mayor, Mr. R. Martin, I told the council that the North Shore boroughs would be included in the scope of the investigations to be made by the visiting drainage experts. The Northcote borough would give every possible ! assistance. I The report was made in answer to a question as to the possibility of the utilisation of the St. Leonard's sewer 1 outfall at Takajmna, as the main outfall of the northern area of the proposed metropolitan drainage district. Mr. AVatkins , reply was as follows:— District Spreading North. "Such a possibility was considered in the course of my investigations of the drainage problem of this area, and I have to advise that it would be practicable to use the outfall for a limited portion of the area. The scheme that I have recommended for the northern area was determined, however, upon the supposition that it is desired to concentrate the whole of the sewage flow from the districts to be eventually embraced in the area to one suitable point of discharge. Having regard to this very desirable objective, and the further advisability of planning for the future expansion of populated areas which must necessarily be in a northerly direction, the adoption of the St. Leonard's outfall as the main outfall for the northern area would present the following disadvantages, as compared with the scheme I have recommended.

"(a) The locality of the outfall cannot be regarded as a central one, if any consideration is to be given to the probable ultimate development of the district. In thi3 connection it is already apparent that the coastal district, lying to the north of the borough of Takapuna, is approaching a stage of development, at which it will become necessary to provide proper drainage facilities.

"(b) The foreshore in the vicinity of the outfall is not as suitable for the establishment of treatment works as the site near Ranopara Point, which I have recommended.

"(c) The sewage flow from a very extensive portion of the borough of Takapuna is already concentrated at the Black Rock outfall,- which is considerably nearer to the Ranopara site than to the St. Leonard's outfall.

Alternative Scheme. "Before determining my proposals with regard to the northern area, I gave some considerable thought to an alternative project, which involved the establishment of treatment works at the head of Shoal Bay in the Waitemata harbour. The St. Leonard's outfall would have been used for the discharge of the clarified effluent from the treatment works, and a separate pipe-line would have been constructed for the transfer of sludge from the treatment works to the foreshore of Rangitoto Channel, for shipment to the- deep waters of the Hauraki Gulf. I considered that such a project would be unsuitable, however, and made no recommendation with regard thereto."