TUNNEL LEAK

New Zealand Herald, Volume LXXV, Issue 23083, 7 July 1938, Page 14

TUNNEL LEAK

COLERIDGE POWER REMEDIAL MEASURES INSPECTION BY MINISTER NO IMMEDIATE DANGER [BY TELEGRAPH —PRESS ASSOCIATION] CHRISTCHimCH, Wednesday The Minister of Public Works, the Hon. R. Semple, is having the closest watch kept on the situation at the Lake Coleridge power statioji, where a seepage in a tunnel has caused some alarm. It has been decided to take remedial measures as soon as possible, but in tho meantime it appears that the supply is in no immediate danger, providing tho seepage and leakage do not increase. The Minister arrived from Wellipgton on Sunday and motored immediately to the lake. He had the water shut off in the tunnel (which is the newer of two tunnels supplying water from the lake), and made a thorough inspection. The chief electrical engineer of tho Public Works Department, Mr. F. T. M. Kissel, and the Hon. G. 11. Hunter, M.L.C., accompanied the Minister, who went far into the tunnel, examining extensive seepages. Close Watch Kept

It is now stated that as soon as tho present high load on the Lake Coleridge-Waitaki system drops the Minister intends to have the water shut off in the tunnel again, so that extensive remedial measures j:an be taken along the sections where tho seepages occur. This will probably be in tho middle of September, when the demands on the system are not so high and the generators from the No. 1 tunnel can be stopped without inconvenienting tho public through any shortage. The repairs will be an extensive undertaking and may take some time.

All day long a man stands along a staging above the No. 1 surge chamber above the powerhouse at Lake Coleridge, watching closely the behaviour of the water as it passes from the No. 1 tunnel (where the seepages are occurring) into the chamber, and then into the great pipe-lines leading down the hill to the turbines. Fear ol Erosion

Apparently there is no fear that the seepage can damage the tunnel, but what is feared is that any increase in the volume of water flowing out would lead to serious erosion of the hillside and possibly a landslip, with disastrous consequences to the powerhouse and pipe-line. Erosion occurring inside the hillside and round the surge chamber is considered _as a possibility. That is why the Minister proposes to carry out remedial work as soon as it is at all possible. Apparently it is the intention of the Minister to increase the depth of the tunnel lining and to strengthen the protection at weak points. In the meantime it seems to be felt officially that there is certainly no immediate cause for alarm.