WAITAKI HYDRO.

Auckland Star, Issue 154, 2 July 1934, Page 3

WAITAKI HYDRO.

STORY OF BUILDING. GRIT AND DETERMINATION. WORK NEARING COMPUITION. When the sluice-gates of the dam at the Waitaki hydro-electric works are closed in August, and the giant turbines begin to revolve, the final chapter will have been reached in a romantic story of how the forces of Nature were overcome by man's grit and determination and were harnessed to become the servant of the people by producing electrical energy (states the "Christchurch Times"). The harnessing of the turbulent Waitaki River, with its tendency to rise from a minimum flow of 3000 cusecs to floods of as much as 160,000 cusecs, has been a hazardous undertaking. Many risks hav° had to be run, and on a number of occasions during the progress of the construction work grave anxiety has been felt by the engineers, but they have come through their troubles with "a minimum of wastage and with an extremely low accident ratio. Six years ago. when Mr. R. H. Packwood, the resident engineer for the Public Works Department, arrived at the site of the dam with plans for the great work on which over £2,000,000 has been expended, there was nothing to be seen but a swiftly-flowing river and an expanse of river bed covered with tussock grass. Construction of Dam. Since then he has hardly left the job, having forgone all the holidays due to him, and lie has supervised the building of the greatest hydro-electric undertaking in the Dominion. Among his first tasks were the construction of a railway from Kurow to the site of the dam, a distance of about three and a half miles, and the provision of cottages and hutments for the hundreds of workers who were required. Then began the construction of the dam, one of the greatest engineering feats in the history of Now Zealand, and so risky was the work at certain stages that it was necessary for Mr. Packwood to remain constantly by his men for as much as three days on end.

Not long after the work had been got well under way, the depression caught New Zealand, and there had to be a slowing down in the rate of expenditure, but throughout the period there were never fewer than 500 men employed, and now that the final stage lias been reached there are about 700 on the job. The peak number of workers was 1250. It has been calculated that, of the total expenditure of about £2,000,000 on the construction of the works, about one-half has been paid in direct wages of employees. City Council Inspection. On Friday morning Mr. Packwood took a party from the Christehurch City Council 011 a tour of the whole of the works, visiting first the point five and a half miles from the powerhouse, where the lake will end. This lake will have an area of 1744 acres when the water is at the contour of the spillway level, and at flood level will have an area of 2200 acres. But at the normal rate of flow in the river, 8000 cusccs, it will take only two days to fill. The powerhouse is at an interesting stage at present. Forming an integral part of the dam, it is 350 feet long by 150 feet wide and reaches a height of 130 feet. Provision has been made for five turbines, each of 23,000 horse-power, operating a generator with a capacity of 10,600 kilowatts, but at present only two unite are being installed. . When two generators are under full load "the turbines will consume the entire normal winter flow of the river. At a later stage when it is necessary to increase the capacity of the powerhouse, a weir will be constructed across tliG outlet of one of the three tributary lakes, Tekapo, Pukaki and Ohau, to conserve an adequate supply of water for five turbines at all times of the year. Tlio most spectacular part of the scheme and the one that has proved most hazardous in the course of the construction work is the dam. It consists of the spillway, 1160 ft in length, and the overall length of the powerhouse 640 ft, a total of 1800 ft. Ihe maximum height of the dam proper is 120 ft, and of the cut-off wall to the crest 143 ft. From the base of the cutoff wall to the lake flood level is 15oft. The amount of concrete used in tie construction of the dam, the powerhouse and the intake structure is 500,000 tons.