POWERHOUSE AT ARAPUNI

Dominion, Volume 22, Issue 175, 20 April 1929, Page 10

POWERHOUSE AT ARAPUNI

> PROGRESS OF THE WORK HAVE THEY TAMED THE TANIWHA? (By E.A.AJ Down below the road that leads to the top of Arapuni dam men are busy to-day giving the last tweak to the tail of the Taniwha that lives In the gorges. The Maoris say that this dragon of the gorge ean never be tamed, however cunningly he be caged he will break loose again. He has made a terrific fight this Taniwha. He has cost the country millions more than was anticipated before he was even moderately tamed. He has put up a fight for two long years beyond the calculated date, but the engineers at Arapuni seem confident to-day that the time has come when he will soon give his last wild wriggle before taking up the electrical burdens of a nation. The pent up powers in the waters of Waikato at Arapuni will not be wastefl much longer. In under two months man will gingerly turn on taps and valves, switches will “snap over” at Arapuni for the first time, water will take its headlong rush from the pentstocks to the turbine waiting down below, one more link will be added to the electrical schemes of New Zealand. There was intense activity in the vicinity of the power house. Men were busy everywhere concentrating on the complicated bridles that will hold in check this Taniwha. “Although there was a lot of talk about foundation difficulties,” said Mr. Rabone, the engineer in charge, “as a matter of fact the work to be done, once we had stopped leakages, was practically as forecasted beforehand. One cavity some fifteen feet across had to be filled in unexpectedly, but that was all, and the foundations rest on good solid rock, '■apable of withstanding all the strains and stresses likely to be imposed upon them.”

A compressed air drill filled the gorge with hilarious echoes. Cranes turned hither and thither, lifting huge loads. A man was assiduously brushing a steel brush over the curious iron walking sticks that are stuck In the cement every foot or so. Cleaning-up parties were busy below the outlet in the bed of the old river, where once Waikato reigned unchallenged. Inside the Power House, Inside the power house, which is three-quarters completed as regards the building itself, an army of electricians were concentrating on the installation. Two turbines not yet completed were partially embalmed in concrete like curious giant shells washed up on the shore. The other alternator turbine was ready practically to the last screw, and the huge 200-ton alternator was in place—carefully sheathed in white cloth to prevent dust and dirt from entering. Men were busy About this god of electricity. Some were putting the finishing touches to the iron work, others were chipping and smoothing the concrete. Snaky cables thicker than a fist trailed away neatly from the monster and lost themselves in the concrete cellars and caves below. The air was fragrant with the curious incense of molten pitch burnt to propitiate the god of the cables and incidentally keep out damp at the joints. We crawled below and saw the steel shaft that links .the turbine to the generator perpendicularly above. This shaft, as thick as a man’s body, had just been linked together. Men were busy at this altar attending to the wants of the god below. Blinding lights of hundreds of candle-power lit them as they worked. Curious shadows played upon them until the whole atmosphere seemed full of furtive stealth and the shrill click of steel .on steel.

A tunnel rose at a sharp angle to the world above where the transformers do their work and huge switches control the power. The cables from the generators filled this tunnel which narrowed into perspective as it rose until a tiny dot marked the entrance at the top. There were over two hundred and seventy steps to clamber up in that tunnel, where all the power to feed a thousand industries will rush to its work.

A travelling crane, the Sampson of the power-hohse, crawled about the rafters like a beetle,- lifting odd bits of metal here and there. The generators were lifted into place by this crane. Each piece weighed a hundred tons and required fitting into place with the precision of a cog in a watch. The generator itself when completed, the engineer explained, would break down In a few seconds if it was put on a ' load without drying out. At a voltage of 11,000 the smallest Scrap of moisture means trouble. Nearly a month before the power is turned on full this generator will have to be carefully dried out, first by hot air, then by running it slowly and letting it warm itself up with its own work. 'A Last Twist. In the old river bed where the water will soon flow once again men . were busily engaged. The “get-away” for the water, must be smooth and correctly sloped so that the generators shall deliver their maximum efficiency. Over 100,000 tons of rubble and boulders had been blasted away for a distance of nearly half a mile. The river bed looked as smooth as a canal bottom smooth enough for tennis courts. All the pot holes had been flattened out. •A small stream trickled down one side and was numned away by powerful pumps as fast as it flowed. Over 600 gallons a second has to be dealt with from natural springs. A series of detonations echoed down the gorge. “Still blowing up rocks in the bed,” said the chief engineer. “Tons of explosives have been used on that job.” Every extra foot of outflow obtained I was told, meant a thousand additional horse-power. A thousand extra horse-power when converted via the meter into cash means a lot of extra income in a year, so money spent on the old bed is money well spent. Although the water will flow nearly as fast as in the original river bed, it will do so much more smoothly and there will be nothing inspiring about it like there was before the dam was made. “When all the turbines are turned oh, the water will not rise more than 10 or 12 feet below the power house,” said the engineer. “It will merely flow quicker.” It is thought that six turbines will take all the water the river has to give “The waterfall to the sunken forest,” I asked, “what will become of that?"

“There won’t be one then,” he said. “The diversion below the race will be empty.” So the Taniwha at present gnawing and tearing and thundering at the falls below the race will be turned to other work—who knows? —the six turbinesare not yet running. The engineers are confident of success. However, they will not cease to fear the Taniwha till its last kick has been officially taken out and the mattei reported to headquarters on the correct and proper form —in triplicate.