AUCKLAND'S WATER

Sun (Auckland), Volume 1, Issue 12, 5 April 1927, Page 13

AUCKLAND'S WATER

SOURCES OF SUPPLY WAIKATO AND TAUPO MR. W. A. GRAY’S REPORT Evidence regarding the suitability of the Waikato River and Lake Taupo as water supply sources, and a criticism of the figures supplied by the City Engineer in regard to the present supply, were submitted to the Royal Water Commission at yesterday’s sitting. The commission, which is appointed to investigate conditions relating to Auckland’s water supply, is being presided over by Mr. A. W. Blair, Wellington, with him being associated Mr. A. Dudley Dobson, civil engineer, of Christchurch, and Mr. A. J. Baker, engineer, Public Works Department, Wellington. Mr. A. H. Johnstone is appearing for the Auckland City Council and Mr. H. M. Rogerson for the combined local bodies. GOVERNMENT ASSISTANCE Giving further evidence this morning in regard to the position of the Takapuna Borough Council, Mr. J. D. Morison, mayor of the borough, stated that the borough was threatened with injunctions arising out of the refusal of the Health Department to allow further building to be proceeded with on the watershed. He understood, however, that the Government would stand behind the borough council in indemnifying them against litigation. He did not think that it was intended to carry out sewerage operations at the lake watershed at the present time. PRESENT SUPPLY A detailed report upon possible water supply schemes and the present supply, was presented by Mr. W. A. Gray, consulting engineer. Witness stated that in conjunction with Mr. Rogers several schemes were investigated in 1924 at the request of several local bodies. It was considered that Lake Taupo should be the ultimate objective and the Waikato River the immediate supply. Although certain engineering difficulties would be presented in the country near Taupo through which the pipeline would pass, the project, from an engineering point of view, would not be difficult. After investigations made over a period of two years he still considered his scheme was a sound and suitable one.

The present Waitakere supply was investigated, and he considered that the calculations made by the city engineer were at fault. In regard to rainfall, it was necessary to exercise extreme care in estimating future rainfall from past figures. Following past records, also the city engineer’s figures, he considered that much drier seasons could be anticipated in the near future than what was estimated by Mr. Bush, and that consequently a much lower supply could be anticipated in future years. The loss through evaporation and run-off in the catchment area, in his opinion, was estimated at too low a figure, taking into consideration the allowance that should be made for a variation with wet and dry seasons. That, also, would considerably affect the supply. To the Chairman: He that in dry years the figures estimated by Mr. Bush were easily capable of dropping by one-half as a result of calculating rainfall and run-off. To Mr. Johnstone: He recommended Taupo as an ultimate source of supply and advised going to the Waikato River immediately. Te latter scheme would involve chemical purification and pumping. He did not know that the Waikato water had been condemned by some engineers. No special provision was made for the swampy country between Huntly and Mercer. TL bulk of the country was very simple to work, and he based his figures on that fact. (Proceeding.)