POWER SUPPLY CRIPPLED

New Zealand Herald, Volume LXV, Issue 19932, 28 April 1928, Page 10

POWER SUPPLY CRIPPLED

NEW PLYMOUTH WORKS. EXTENSIVE SLIP OCCURS. * COLLAPSE OF HILLSIDE. RESTRICTION OF THE OUTPUT. [BY TELEGRAPH.—OWN CORRESPONDENT.] NEW PLYMOUTH. Friday. A portion of the water-race, some 100 ft. in length, at the New Plymouth hydroelectric works, was carried away, when an extensive slip occurred about 7 o'clock this morning at the south end of the syphon pipe which carries water across the Mangamahoe gully. The bulk of the generating plant in the power-house at Mangorei is now idle, and permanent repairs \yill cost several thousand pounds. The position is so serious that some days must elapse before even temporary repairs can be made to carry water to the race on the other side of the valley, and thus to the surge chamber above the power-house. The slip occurred with remarkable suddenness, and transformed the whole configuration of the immediate locality. The whole hillside for hundreds of feet suddenly moved westward into the Mangamahoe Stream below, and immediately water poured from the race, which was running to capacity owing to a flood in the Waiwakaiho, down through the gap, where it gouged out the soft clay to a depth of 4Clft. or 50ft.

Clay and Broken Concrete. An impressive scene confronted visitors this morning. The race, which carries water several chains from a small storage lake that is fed directly from the Waiwakaiho Stream through No. 1 tunnel, instead of emptying itself into the syphon pipe, ended abruptly in mid-air. Forty or fifty feet below were huge masses of clay, mingled with broken concrete. The floor of the valley was flooded by the waters of the Mangamahoe and the surplus that had been diverted from the upper entrance to the race into the Mangamahoe Stream. Across a chasm a small remnant of the end of the race joined to the syphon pipe was precariously perched on a crumbling hillside. The occurrence was observed by the Borough Council's caretaker, Mr. Smith, who was making his morning rounds. He suddenly saw the hillside bulge outward, as though pushed by some gigantic power. A great mass of land swept down into the stream below. Then came water from the severed race, and it. quickly began to gouge out the loose earth. Vast Scouring Occurs. Mr. Smith immediately went to the storage lake, from which the water was drawn, and opened the overflow into the Mangamahoe Stream, thus diverting the water from the race. Even in the brief period the water was running immense scouring occurred, and but for the fact that somebody was handy to act as the caretaker did, the consequences might have been even more serious. A small crack had developed in the race just previously, and steps were being taken to have it repaired. One explanation is that the dry weather had opened up many fissures in the hill, and the leakage, combined with heavy rain, forced its way through, causing the hill to slip. Over a wide area the ground has cracked and small falls are likely to occur at any time. Tram Service Curtailed. The power supply for New Plymouth is being partially maintained by plant, working on a low head, which is obtaining its water from the MangamaEoe Stream. This plant is capable of generating only about 700 horse-power, and other assistance is being received from the fertiliser works and the Tariki power system. Consumers found current very feeble to-day. The tram service is to be suspended daily between 11 a.m. and noon, and in the evening, and further curtailment is likely if some other assistance cannot be obtained.

The Borough Council held an emergency meeting this afternoon to consider the position. The engineer, Mr. C* Clarke, said he believed the hillside had contracted during the long spell of dry weather, and recent rains and the heavy fall of last night had undermined it. Ho recommended repairs that could be done in under two weeks. The engineer was empowered to proceed with the work and have it carried out by three shifts daily if possible.