CIVIC WATER SCHEME

Sun (Auckland), Volume 1, Issue 16, 9 April 1927, Page 10

CIVIC WATER SCHEME

ENGINEERING APPROVAL TAUPO UNNECESSARY TUNNEL WOULD COST £BOO,OOO Professional approval of the various schemes carried out by the Auckland < *ity Council and also those set down for future additions to the city’s water supply was given by Mr. R. W. Holmes of Wellington, late engineer-in-chief of the New Zealand Public Works Department, in giving evidence before the Water Commission yesterday afternoon. Dealing with the question of rainfall Mr. Holmes stated that from a long experience of rainfall on the western coast he considered that the rainfall in Auckland from 1833 to 1920 averaged 44 inches per annum, that also including the period between 1872 to 1915, during which rainfall was much below the average. No record had been kept of the rainfall in the Waitakere Ranges, and he assumed that a. fair addition above that which fell in Auckland would be 50 per cent., giving 66 inches per annum. That assumption, said Mr. Holmes, was afterwards borne out by the city engineer’s observations. Of that amount he considered that over the whole period approximately 50 per cent, of the rainfall would reach the streams and be available for storage, giving a run-off of 33 inches. TAUPO TUNNEL In regard to the Lake Taupo scheme he considered that about twice the money estimated by Messrs. Gray and Rogers would have to be spent before the scheme could be developed. He did not think that a tunnel 7ft. high »nd 6ft. wide could be driven for a length of ten miles, and was of the opinion that a tunnel for the purpose required would cost approximately £ 800,000 instead of £220,000 estimated, for the purpose of putting the tunnel through he was decidedly of the opinion that it would need to be at least lift, wide, and the walls 6ft. high at the sides and of a height of 9ft. or 10ft. in the centre. When the Waitakere water was filtered. concluded Mr. Holmes, he did not think there would be any need to go to Lake Taupo. He knew the works that had been carried out by the City Council, and as an engineer approved of them. At the conclusion of yesterday’s evidence the commission adjourned to resume on Thursday, April 28.