DIVER'S DIFFICULTIES

New Zealand Herald, Volume LXIX, Issue 21252, 4 August 1932, Page 10

DIVER'S DIFFICULTIES

HORIZONTAL IN CURRENT AN INGENIOUS AID CAR CHASSIS SUNK UNDER-WATER CONVEYANCE [BY TELEGRAPH —SrECTAT, HSronTF,ll] ARAPTTNI, "Wednesday Tcculiar difficulties are confronting the diver who is endeavouring to find the intako of the leak in tho headrace at Arapnni. Tlio current of water flowing in tho channel is so powerful that it is impossible for him to stand upright. As soon as ho climbs over tho side of the punt, which is moored by guy ropes in mid-stream, and his hclmctcd head disappears beneath tho surface, he is swept off his feet and observers peering into the dim depths can faintly mako him out swinging with tho current in almost a horizontal position, this in spite of . his heavily-leaded boots. A ropo is lowered to him and by holding on to it he is able to crawl about the bed of the race, examining the floor for signs of a fissure. He employs no tools or instruments, merely watching the

rocky floor for a disturbance of water or an actual opening. Although it is impossible to 6co the bed of the race from the surface, the •water being 10ft. or 12ft. deep and the floor dark in colour, the sunlight makes visibility easy for the diver. The Diver's "Oar" Yesterday ho was engaged in inspection of the "tiled bath," as the special lining is familiarly known. This was even moro ticklish work, as the current in this part of tho race is speeded up on account of grade and the smooth surface of the concrete tiles. Every time he entered the

water ho was swept off his feet, his body being clearly visible in a perfectly horizontal position. To get over the difficulty, a motor-car chassis was lowered into tho water and to this the diver held on by his hands, while the cradlo on wheels was moved up and down tho bed of the race by means of cables stretchfcd to the shore. Conveyed by this contrivance with the greatest of ease, the diver was able to maka such a thorough examination that positive proof was obtained that the cause of tho leak is not to be found in the tiles or their bitumen binding. Tests by Dye

The use of a green dye by the diver was an interesting feature of this afternoon's operations. Going over the side of tho punt, he wa3 handed a bottle containing the dye and a spanner with which to break it in the water. He submerged, and it was possible to trace his movements by the released air bubbles until he arrived at tho spot where his suspicions had been aroused by the black, peaty nature of the bed. A few moments elapsed and then the water in the vicinity of the bubbles suddenly grew a vivid green. The bright coloured patch expanded and then flowed downstream until it was lost to view. A few minutes later the diver emerged, and when his helmet was removed he reported he had smashed tho bottlo in what appeared to be a crevice in the middle of the peaty patch. The time when the bottle was bi'oken was noted and observers in the shaft in the race leading to the main drain which runs the length of the tiled portion commenced to take samples of the seepage water at intervals for a period of four hours, and these were carefully compared with samples taken before the dye was used, but the results were negative. Dye tests have been very successfully employed in locating leaks in the bed of Lake Waikaremoana and have also been extensively used at Arapuni on many previous occasions. NOT BELIEVED SERIOUS MR. FURKERT'S STATEMENT SMALL AREA OF LEAKAGE [by telegraph—OWN correspondent] WELLINGTON. Wednesday The engineer-in-chief of the Public Works Department, Mr. Furkert, stated to-day that the trouble at Arapuni was not regarded as serious. Ho had inspected tho plant since the seepage was first reported some days ago and on returning to Wellington announced that the engineers considered that once they traced the source of the leak there should bo no difficulty in stemming the flow. Within the past 24 hours there had been a decrease of 25 per cent in the discharge. An important consideration was that the water coming through the drainage pipe was clear, which showed there was no erosion of the soil in tho area where the seepage was occurring. It was admitted that if tho amount of water increased tho effect on tho works might bo serious. It was apparent, said Mr. Furkert, that tho seepage was occurring at a point above the lined portion of (he headrace on tho other side of tho cut-off wall, under or round which tlio water was finding its way. A six-inch post-holo boro had been sunk near tho wall and this showed that water was present, lending colour to the opinion that it was finding its way round tho wall and under the impervious lining. Tho source of leakage had been confined to a space about 12 feet square on tho east side. If tho seepage was definitely

traced to that source its flow might be checked by tho dumping of spoil and concrete grouting. It might prove necessary to dewater tho headraco to rectify the fault, although it could not bo said at tho moment whether this would ho necessary. Tho probability -was that it would not bo necessary. As the plant was generating 50,000 kilowatts and earning £SOO a day it could bo understood that it would not bo closed down unless this course proved absolutely necessary. RIVER RISES AT HAMILTON PUMPING NOT AFFECTED [FROM OUR OWN correspondent] HAMILTON, "Wednesday The level of the Waikato River at Hamilton had risen 3ft. 6in. above normal this morning as the result of tho partial opening of the gates in the diversion tunnel at Arapuni "last evening. During tho day the level receded 6in. Pumping operations at tho borough waterworks havo not, been affected, as

little sediment is being brought down the river. EFFECT AT HORAHORA PROTECTIVE WORK SUSPENDED [from our, own correspondent] HAMILTON, Wednesday The construction of a concrete apron below the weir at the Horahora powerhouse, which has been under way for some timo, has been suspended as the result of the heavy increase in the flow of the river. A liftht railway line erected in connection with the work has been underpinned and is suspended in midair.