The Evening Star FRIDAY, SEPTEMBER 14, 1934. KAIKORAI VALLEY DRAINAGE.

Evening Star, Issue 21825, 14 September 1934, Page 8

The Evening Star FRIDAY, SEPTEMBER 14, 1934. KAIKORAI VALLEY DRAINAGE.

Tan Board of Health deputed a local committee of three gentlemen to investigate an application from the Green Island Borough Council for authorisation to instal a drainage system, at an estimated cost of £40,000, without a preliminary poll of ratepayers. That committee reported lo the Board ot Health, recommending it to issue the requisition enabling the Green island Borough Council to carry out its scheme, and the Board of Health has now approved that recommendation. At first sight it would appear that, after nearly forty years of discussion, the removal of a long-standing evil is within sight. We are not so optimistic as to accept that view unreservedly. A condition is attached to the Green Island Borough Council’s scheme which may cause that body to think twice over the prospective cost: the sewage outfall must be at a level not less than fifty feet below low-water mark, or it must be at a point in the vicinity of Black Head. The engineer (Mr A. Slinger), who carried out the major part of Dunedin’s drainage scheme, including the ocean outfall at Lawyer’s Head, subsequently made a preliminary investigation of the Kaikorai Valley drainage problem, and he considered either of the two outfall propositions mentioned above as being prohibitive in cost. Mr Slingcr’s proposal was an outfall located in the sand dunes to the east of tho- mouth 'of tho Kaikorai Stream. This, however, the committee considers, will in time become a popular resort, and, as the committee insists there must be no beach pollution, even with an ocean outfall, it is quite unlikely that the Board of Health would remotely consider discharge in the dunes.

The committee presumably has its doubts as to Green Island Borough facing the expenditure involved in a scheme hedged round with such conditions; for, even if the council adopted the shorter route with an ocean outfall near the mouth of the Kaikorai Stream, the Health Department would have the power to compel its abandonment and taking, the outfall to Black Head. A scheme to serve Green Island only, ■ and to be financed by Green Island only, appears uneconomical, in that the benefits would be disproportionate to the cost. What is needed is a comprehensive scheme to serve the whole of the Kaikorai Valley, including Green Island. Unquestionably the committee recognises .this, for it recommends that steps should be taken to constitute the Dunedin Drainage Board a “ local authority ” for the purposes of the Health Act. If that were done the Board of Health could call on the Dunedin Drainage Board to make complete, instead of (as now) only partial, provision for the drainage of the upper part of Kaikorai Valley. That, however, would still leave Green Island .to cope with its own drainage problem. Therefore the committee expresses the opinion fthough not in the form of a recommendation) favouring Mr Short’s view (1903) that one paramount authority is required, that this should be .the Dunedin Drainage Board, and that the Dunedin drainage district should be extended to include Green Island Borough and a small part of Taieri County. Furthermore, the committee states that this should be done as soon as practicable. In its opinion it must come about sometime, and the sooner the better. That desirable time might, however, be delayed indefinitely if in the meantime the Green Island Borough Council embarked on a scheme quite -independent of the Dunedin Drainage Board. It is possible that such a scheme, whether in its engineering or its financial aspect, might be at variance with the views of the Dunedin Drainage Board. One thing is evident, and that is that the committee regards remedial action as urgent and places no obstacle (excepting the stringent outfall stipulations before-mentioned) in the way of it being taken by either authority. It recommends the Health Department to enter into negotiations forthwith with the Dunedin City Council, the Dunedin Drainage. Board, and the factory proprietors to prevent pollution of the stream in the upper part of the Kaikorai Valley, this being a contributory cause to the nuisance which has provoked Green Island Borough to action. Kxisting conditions may Ire briefly outlined. In the upper part of the Kaikorai Valley household drainage is provided for by the Dunedin Drainage Board. This dr-ainage is led by gravitation through the old Caversham tunnel into the Dunedin system, together with part of the discharge pumped from three important industrial undertakings in the vicinity of the tunnel entrance. There are, however, factories along the stream above, and their effluents go back into the Kaikorai Stream. If, as recommended, the Dunedin Drainage Board Is requisitioned by the Board of Health to “ instal a comprehensive scheme of drainage which would make provision for factory- or industrial effluents as well as domestic sewage in that part of the valley within the boundaries of the drainage district,” the Dunedin Drainage Board might plead that immediate provision of this and contemplated future provision for the needs of the whole valley might be incompatible or needlessly' expensive. If such a plea were raised the committee could not logically' disagree, because the first paragraph of its report states: A complete drainage scheme for the whole of the Kaikorai Valley, to include both domestic and industrial drainage, is urgently required. This, wo think, is incontestable ; and it is also highly' desirable that this complete .scheme should be exclusively' the task of one controlling authority. Already the Dunedin Drainage Board makes partial provision for om; part of the valley. .Is the same board willing to undertake complete provision for the whole of tbo valley;- And is the Green Island Borough Council willing that the Dunedin Drainage Board should do

so? Fox- an early solution of a longstanding problem it appears that an affirmative answer to both questions is required. Not only is it an advantage that there should be one controlling authority for a' district geographically one unit, but it is very desirable that water and drainage' should be under the same authority. The, JDunedin Corporation (which now, includes the Drainage Board) controls the prospective water supply without which there can bo no drainage system. Up to the present lack of the necessary watersupply is the paramount reason for the long-standing evil continuing until now, despite many protests and investigations. Now that water is within reasonable sight we hope Green Island is within reasonable sight of relief.