TEN MILLION GALLONS

Sun (Auckland), Volume 1, Issue 13, 6 April 1927, Page 13

TEN MILLION GALLONS

AMPLE WATER SUPPLY THE CITY’S SERVICE ENGINEER’S ESTIMATES With a total daily supply of S£ million gallons, shortly to be increased by an additional li millions, Mr. W. E. Bush, engineer to the Auckland City Council, stated in the course of evidence given to the Royal Water Commission this morning, that the water supply for the district was available for all present requirements. Regarding the future, he considered that works, now in hand and pending, would assure an adequate supply for future demand. RAINFALL RECORDS Dealing with the history of the council's waterworks Mr. Bush said that when he arrived in Auckland in 1906 the City Council was just letting the contract for the construction of the Waitakere dam. Information legarding the rainfall at Waitakeres was very scanty, so in ino9 he prepared figures regarding rainfall and run-off. The methods of rainfall available were the Auckland and Waitakere records and stream gaugings and the particulars of run-off in districts similar to the Waitakere Ranges. In January, 1911, he installed a rain gauge and found that the rainfall at for the five years, ending December, 1915 averaged 40.3 and at Nihotupu 68 points. Working on the figures for the three dryest years as supplied by Mr. Gray the rainfall at the Waitakere’s would have been 54.17 instead of 47.35 as estimated by Mr. Gray in nis evidence. In that district a better run-off could be expected, and he had estimated that 60 per cent, of the water was taken. He did not think that any evidence could be brought to support Mr. W. Gray’s contentiqn that the run-off was only 40 per cent. The period from 1911 to 1915 over vihich the figures were taken was a particularly dry one. In 1914 the figures, 28.46 inches, were in fact the lowest on record. It would thus be seen, said Mr. Bush, that the figures were not based on the district’s largest rainfall figures as stated by Mr. Gray. CAPACITY OF SUPPLY In 1919 a very dry season was experienced, 36.41 inches being registered in Auckland and 46.71 inches at Nihotupu, and as a result an auxiliary dam was erected. At Nihotupu the catchment area was 2,374 acres and the total storage capacity was 600,000,000 gallons}, while at Waitakere the capacity was 220,000,000 gallons. The total daily supply was 8i million gallons, but that would be raised to 10 million gallons when the present Waitakere additions were completed. When the North Shore main was ready to tap Waitakere the demand would be increased from that source alone by a million gallons, but by that time the Huia works would be completed. From the figures available, and which were based upon actual experience, he was of the opinion that an ample supply would be available.