DRAINAGE PLAN.

Auckland Star, Volume LXVII, Issue 116, 18 May 1936, Page 8

DRAINAGE PLAN.

BROWN'S ISLAND.

PROGRESS WITH SCHEME.

SERIES OF CURRENT TESTS,

The Auckland and Suburban Drainage Board recently authorised further investigations concerning the proposal of establishing sewage treatment works on Brown's Island, with an outfall into the adjacent tidal waters. This is to provide for tlie drainage scheme recommended by the secretary-engineer, Mr. H. H. Watkins, and under consideration for the southern area of the proposed Auckland metropolitan drainage district. The chairman of the board, Mr. Ernest Davis, stated to-day that further current tests, using meters and floats, of an exacting nature had been made over an extensive area of the waters surrounding the island. These had been under the supervision of the actingsuperintendent of the Auckland Harbour Board, Mr. D. Holderness. The results of the tests permitted of the most suitable area being determined for the outfall.

Soundings would now be taken to find the levels of the sea bed of tlie#selected area, so that the most advantageous site available might be chosen for the construction of the outfall. This, it was planned, should consist of several pipe lines with multiple outlets. The direction and velocities of the tidal currents in the vicinity of the outfall site would then be further examined, under varying tidal conditions and wind directions.

Arrangements were also in hand for Dr. W. Gilmour, pathologist at the Auckland Hospital, and his staff to conduct a series of chemical and bacteriological .tests of the sea water in the vicinity of the Orakei outfall during discharge operations. The analyses obtained would form a basis for estimating the demand likely to be made upon natural purifying agencies of the sea water in the process of dilution and disposal of the clarified sewage efflueftt proposed to be discharged from the new outfall. Mr. Davis added that in view of the vital importance of the matter the authorities concerned were leaving nothing to chance.

Mr. Davis has already announced that, if the investigations confirm the desirability of Brown's Island for the site of the treatment works and outfall, he will invite members of the Drainage Board and representatives of other interested local authorities to accompany him on a visit of inspection of the locality. The results of the present investigations will be embodied in a report, with explanatory drawings, for consideration at a special meeting of the board.