WATER PROBLEM

Auckland Star, Volume LXXIV, Issue 75, 30 March 1943, Page 4

WATER PROBLEM

WAIKATO RIVER PLAN

MR. E. H. POTTER'S REVIEW

Commenting on the current water shortage and the earlier discussions on plans designed to supply the needs of the city and areas southward, Mr. E. H. Potter, who has taken a leading part in urging the adoption of the Taupo scheme, writes:— , . i Nineteen years have passed since the local authorities met in conference with the Health Department and resolved that the time had come for the formation of a water board. It was then stated that the rainfall precipitation over the catchment area draining into Lake Taupo would suffice for the needs of a population of many millions, so that it is for all time a reservoir for the water supply of provincial Auckland, after making full allowances for all future hydro-electric development on the Waikato. The high elevation of the lake would enable it to feed water to a chain of high service reservoirs located on the watershed of the country radiating out from the lake, so enabling water to be supplied by gravity to any part of the country for all towns as far north as Auckland and for irrigation. Purely Gravitational Scheme. The main Taupo scheme provide for supplying 15,000,000 gallons a day direct from the western bay of the lake to a reservoir on One Tree Hill at a height of 5.00 ft, the whole plan being estimated to cost £2,482,000. This scheme was purely gravitational, no pumping oi any sort being involved. Ine reticulation within the individual borough boundaries would be controlled by the local authority, hence the charges were practically limited to provision of interest and sinking The supply from the river below Cambridge involved pumping to a reservoir on a suitable site, from which the water would gravitate to Auckland. If delivery, be made to a reservoir on One Tree Hill at a height of 300 ft, a portion of the water delivered would need to be pumped to a 500 ft reservoir,- to-sup-ply the higher areas, at an estimated cost of £2,000,000. The Lower Waikato scheme was recommended as an emergency supply, to form part of the main scheme at Mercer or Tuakau, at an approximate cost of £700,000. . ■ At the Royal Commission of 1927 it was established that the council would by 1940, have to extend its sources of supply, and, further, that if the supply was not taken fronvtne lower Waikato at a point about Mercer or Tuakau, the only reasonable alternative was to draw supplies from Mangatangi - Maungatawhin and Cossey's Creek areas. The cost of the Mangatangi - Maungatawhin proposal as estimated by the council's engineers in 1927 was, for the first part of the scheme, £1,600,000, and for the complete scheme £2,700,000. Water At Cheap Rate Engineering data shows that the minimum flow at Mercer is at least 5,000,000,000 gallons daily, and the maximum quantity of water likely to be drawn would have no appreciable effect on the navigation of the river. The standard practice of filtration and chlorination would be desirable in the treatment of water from Tuakau. The Cambridge supply would ensure an absolute pure water to a larger number of consumers at a cheap rate. The actual increase in the cost of the pipe line and reservoirs compared with the cost of 15 years ago cannot ■be ascertairiable with any- degree of» accuracy; 60 per cent to 100 per cent may be accepted as an estimated increase, 'but a scheme that will give the best immediate ' results, where millions of gallons of running water can be pumped to a given point or conducted through water mains will appeal to the local authorities and general public. The Waikato River scheme at Tuakau pumping •to a reservoir on Pukekohe ~ Hill, from which the water will gravitate "to Auckland with a later extension to Cambridge, offers an immediate solution' to the water supply problem.