THE WATER SUPPLY

Evening Post, Volume CXV, Issue 121, 25 May 1933, Page 12

THE WATER SUPPLY

WORK UNDER LOANS

PLANS TO GO TO BOARD

UNAVOIDABLE DELAY

Though the ratepayers have cx-^ pressed their agreement with the pro-1 ! posals of the City Council to spend approximately £70,000, part of the £113,000 loft over from the big waterworks loan (£561,900) authorised in 1920, and though a commencement of the works to be undertaken would help materially in relieving unemployment and improving things generally in tho city, it will not be possible for construction work to bo commenced for some time. Probably the first work will be done about July. As the success of the poll was regarded as very doubtful before the vote was taken, for no one anticipated that three ratepayers would say yes to'every one Who would say no to the proposals' that the money should be spent, only scheme plans were prepared. Immediately the result of the poll was known instructions were issued for the drawing of detailed construction plans, and this work is now in hand for all jobs, and will bo sent on to the Local Bodies Loans Board for approval. The next meeting of the board will take place iv June, and though full approval may then be given by the board there will still be unavoidable delay, at any rate as far as work on the mains is coneerned,_as' the business of calling for and considering tenders for material must occupy some weeks. If the tenders include quotations from English or other overseas manufacturers the delay may be considerably longer before a sufficient supply of pipes and other material is oil hand to allow trenching and laying of new mains to proceed without interruption. Tho excavation of the suburban service reservoirs is a fairly straight ahead job. but the reorganising of the city and suburban main system must be carried through according to carefully drawn and co-ordinated plans to maintain an uninterrupted supply. • SUPPLY FROM ARTESIAN WELLS. The other loan .proposal approved is that the present supplies from tho Wainui and Orongorongo systems should be augmented by water obtained from artesian bores at Gear Island ar.d pumped into the mains from Wainui to the city. "All the Corporation's mains pass through the selected locality within a few feet of the proposed well location," said the City Engineer, Mr. G. A. Hart, in a further explanation of this scheme. '' A considerable amount of investigation was carried out by the department in collaboration with the Government geologist, before this site was decided upon. The area was proved by sinking five small 3in test wells across the/ bottom of Gear Island approximately at right angles to the flow of tho underground stream. AMPLE FLOW ANTICIPATED. "These wells have been flowing continuously since before the Christmas holidays, and although, put down primarily for the purpose o?. testing tha area, a flow of approximately one million gallons per day has been obtained regularly from them alone. As the proposed development is only required to provide an additional supply of three million gallons per day, it is considered that this strip will easily provide this quantity, and probably, more, ■without any appreciable alteration to the conditions of flow of the underground supply,, This view is endorsed by the Government Geologist, who has examined in detail all the data obtained by the City Engineer's Department during tests. "The development of the area and tho arrangement of pumping machinery necessary to deliver the water into the existing mains ana the necessary alterations to the reticulation system oi the city, will take some time to complete, and it will, probably be well on in the ensuing year before this development is in operation. "One of the first works to be undertaken when, these supplies are available will be the cleaning out of the Wainui dams and mains. This system has been in constant operation for a period of about fifty years. The dams have been materially affected by siltation, and the discharging „ capacity of the mains seriously reduced by encrustation. This problem has confronted previous engineers, who, however, have not becu in a position to undertake cleaning operations to the mains owing to the necessity of maintaining without interruption the supply to Wainui."