GREAT LAKE TO BE EMPTIED

Dominion, Volume 23, Issue 218, 11 June 1930, Page 12

GREAT LAKE TO BE EMPTIED

ARAPUNI TURBINES STOP TO-DAY

BRIDGE TOWER OUT OF PLUMB NO FURTHER EARTH MOVEMENT RECORDED 1 Dominion Special Service. Auckland, June 10. to Je SV?S race “1 tower tor the WrMnes, Th. be so reduced th po p w> Furkert, chief engineer of ?n an pnhik- Works Department, said to-day that the emptying of the lake will be continued. The eastern tower of the suspension bridge has been '"“LI by . diver yesterday, It Is reported that ~ nrnnk between the spillway and the entrance to the penstocks exterls two feet St? tangenUnto the foundations of the weir and tapers from two inches to a point. The crack has been packed with sacking.

One very assuring circumstance is that where the crack meets the mud there is no flow. If there were, mud would be washed away. This is strong evidence that the fault does not penetrate into the bed of the head-race and supports the assumption that the fault is localised and that it is trivial on the geological scale. No further earth movement has been recorded.

No Fault On West Side. A most careful search for evidences of fault on the west side of the headrace has failed to reveal any signs of dislocation there. Checks, however, are now being made. Old survey marks are being located and the engineers will soon know definitely if any movement has taken place on that side. Bridge Tower Out of Plumb. On the east side, outside the main line of the fault, stands one of the towers which carry the suspension bridge across the gorge. This has been found to be slightly out of plumb. This circumstance might support the theory that the movement of the country has been eastward. But it is not definite at all. Indeed, it might have no relation to the movement, or it may be evidence only of one of the minor cracks branching off the main one. It has been persistently affirmed that there is a fracture in the weir. This is not so. All that supports the story is that at the angle of the junction between the weir and the penstock intakes structure, the irregularity of the break involves a break in the projecting ledge on the upstream side. The crack does not penetrate the body of the weir. Weir Structure Sound. It can be affirmed with the authority of Mr. F. W. Furkert, chief engineer of the Public Works Department to support it, that the structure of the

weir is sound, and that the only break Is at the point of junction. Rain Increases Water Level. Heavy rain last night and to-day is increasing the volume of water flowing into the lake and adding to the amount of water to be discharged before the level of the penstock tunnels is reached, when the station will have to close. Nevertheless, at the present rate of discharge this point will be reached to-morrow evening. To-day the diversion tunnel is carrying 9200 cubic feet of water a second, and two turbines are discharging a total of 3000 cubic feet, the aggregate being 5000 cubic feet more than the normal flow of the river. It will take about four days after the machines stop to lower the lake to stop the flow into the head-race, but even then the bed will not be ready for examination, for a certain amount of water will be impounded by the weir. This will have to be pumped out, and the probabilities are that a week will elapse before the bed will be completely unwatered and ready for inspection and the start of remedial measures. COMPLETE SURVEY REPORT TO CABINET Th Minister of Public Works (Hon. W. B. Taverner) returned to Wellington yesterday from a short visit to Arapuni, where he made a thorough inspection in company with departmental experts. He repo-‘"d upon the occurrence of the faults to Cabinet in the afternoon, the whole position being fully explained. Public Works Department engineers and the Government geologists are remaining at Arapuni in order to carry out an exhaustive examination of the country surrounding the works as soon as the water level in the headrace channel falls sufficiently? Until this takes place, nothing definite can be done, and no developments are expected for a few days unless there are further earth movements.