POWER FOR TARANAKI.

Taranaki Daily News, 24 September 1924, Page 6

POWER FOR TARANAKI.

THE TARIKI SCHEME. PROGRESS OF THE WORKS. TEMPORARY POWER SUPPLY. At the invitation of the Taranaki Electric Power Board, about fifty members of the Taranaki branch of the New Zealand Civil Engineers’ Association, County Council officials and others interested visited the board’s works at Tariki and Motukawa yesterday. They were 'accompanied by members of the board and were conducted over the works by Mr. H. R. Climie engineer to the board. The party met at the pole depot, Tariki. and inspected the work incidental to the manufacture of the special reinforced concrete poles designed by Mr. Climie and turned out by the board’s employees at the rate of 400 to 500 a month and a cost of 65/- each. There are now hundreds of these poles in use in Taranaki and they are giving every satisfaction. The party next visited the head works at Tariki, where much favourable comment was made upon the progress of the works. Interest centred firstly round the big weir, which formed a striking picture as the water cascaded over the weir and churned on its way down the river bed. Back in the cars again, the party travelled via Kaimata and the Tarata Zig Zag to Motukawa, where the main power house is to be erected. Here lunch was served after which the visitors were entertained to a description of the works by Mr. Climie. Later, in batches of a dozen at a time, the party were taken into the tunnel to watch rhe huge tunnel-cutting machine at work. POSSIBILITIES EXPLAINED. Mr. Climie, in explaining the possibilities of developing such a favourable scheme in Taranaki, said the Manganui river, from which the board drew the bulk of its water, converged gradually with the Waitara river, and the distance between the headwaters and the power house by the Waitara was about miles. The Manganui was the main drainage basin for that point of Taranaki round Tariki and tending through to Inglewood. It was proposed to divert this stream through tunnels and races to a point where its water would be most effective. Not only the Manganui, but other creeks and streams would also come into the broader area of the board’s complete scheme. The fall between the Manganui and the Waitara was 430 feet, about 30 feet of this fall was lost in the swamp and a further 70 feet owing to the situation of the power house. This left the board a 330 foot fall for purposes of electrical generation. From the head works the water, would flow through the Mangatea swamp in an open drain under the present scheme, and then it would be carried through a small tunnel and discharged into the stream at Ratipiko. Owing to the introduction of • fresh water the stream would be backed up for about two miles in an easterly ‘ direction. Th e main tunnel would be extended at that end in order to save deep- j ening the stream. The big tunnel would be about two miles long and pipe lines would convey the water at the Motukawa , end direct to the turbines in the power house. There would be capacity in the j tunnel for 8000 horse power and the pipe lines would have a capacity of 4000 horse power. WATER AVAILABLE. Touching the question of available water, Mr. Climie said th e Manganui flowed at the rate of 70 ed.s., which would develope 4000 horse power without any storage, It would however, be necessary to have some storage so that a resevoir could fill up during the night and be available for peak load periods in the daytime. The board had pondage in the proposed dam at Ratipiko, where 80 acres could be ' easily flooded, sufficient to develop 4000 horse power for three days. The next point in the development of the larger scheme would be the inundating of the Mangatea swamp, about 1000 acres in area to a depth ranging from 40 feet to nothing at the edges. This high resevoir would give about 8000 horse power and it would then be necessary to lay another pipe line and instal another generator. rh e initial estimated cost of the scheme was £lOO,OOO, which included the generator plant, power house, tunnelling, roading, i bousing, etc. The tenders for the pipe line I and generating plant had been so much i below the board’s expectations that instead ' of the two pipes of 2200 horse power ■ capacity it had been decided to lay one line only at present, capable of transmitting the required 4000 horse power. In order to cope iyith immediate demands for power, the board bad erected a temporary power house at Tariki, capable of generating 220 horse power. This power house was now in operation, though only loaded up to 50 per cent, of its capacity. In addition 135 horse power would shortly be drawn from the Eltham dairy factory and this Would supply the southern end of the area until the larger scheme was ready. TUNNELLING MACHINE. The outstanding feature of the works was the huge tunnelling machine now operating in the big tunnel. The machine cost £3OOO, but owing to the ease with which it did its work, and taking into consideration the length of the tunnel, it worked out at a very low cost per foot of excavation. The makers had claimed that the machine would do three feet per hour in the papa, but under actual test 3ft 3in was cut. The greatest amount cut in one hour, including the work of laying rails and removing spoil, had been five feet. At the present time they were working into hard rock and boulders were frequently encountered. When the gangs became thoroughly used to the work it was confidently expected that half a chain would be cut daily, and at this rate the tunnel would be completed in 12 months’ time. Work on the power house would commence next month, and it was expected to have this work and the laying of the pipe line completed by the end of the summer. Mr. T. M. Ball, ehairman of the Taranaki branch of the Civil Engineers’ Association, thanked Mr. Climie for the lucid explanation of the works. He congratulated the board on having such an efficient, engineer, and in company with his fellow engineers looked forward in confidence to the successful completion of the under-

taking. Mr. Ball also thanked the Power Board for their eourtesj in extending the invitation to the society and JAkshpwing njj.