ARAPUNI TUNNELS

Hokitika Guardian, 16 April 1932, Page 2

ARAPUNI TUNNELS

TWO' MILES OF GALLERIES

(By tress Association)

WELLINGTON, April 15,

A |:om' of the wontlciful subterrnnean tunnels and galleries at Arapuni, bored deep under the ’spillway weir, headrace and falls as part of the remedial measures now brought to completion, was made recently. He walked below ground for two hours, .seldom tradersing the same tunnel twice, and covered two aides under the earth before he emerged once more into the light of day. This journey through Arapuni s extraordinary catacombs revealed the gigantic amount ‘of invisible work which has been carried out in the country affected by the troub.fi ill June, 1930. Who would guess, watching the diverted Waikato pouring over the spillway and falls, that 14011. beneath the surging water men were patrolling hidden galleries day and night, watching for '.the first sign of Lakage, peering at V-no:cites embedded in the 'floors

end recording their observations in little notebooks p Two miles of tunnels, deep down in the earth, ablaze with electric light, crossing and recrossing each other—a veritable witch s maze ! Donning gmnboi.ks and an overcoat, not always essential, for the tunnels are dry for the most, part, the "Herald’’ representative was conducted on his underground journey by an engineer. A guide was necessary, for the chances are a hundred to one that a stranger, once in the bowels ot the earth, would lose Uinrseli in the battling series of intersecting tunnels, and fail to find his way out for a good many hours. AN EERIE .SILENCE.

The til'A tunnel had its entrance in he gorge near the power house. Unlocking the padlock on the gate, the guide led the way into a brightlyI ghted cavern 'that penetrated the hill underneath the transformer station. After walking for a quarter of an Dour in eerie silence, the root ot the cavern almost touching one’s head, a faint rumble was heard ahead.

"We are under the spillway,’’ said the guide. Another tunnel junctionid to the left. This, it was explained, followed the entire length of the forebay and headrace and into it ran a series of porous drainage channels. There was a considerable, quantity of water flowing through 'this tunnel under the headrace. “That is not leakage through the tiles,” said the -■nginecr, observing a questioning look on his visitor’s face. ‘That is purely seepage from the country on both sides of the headrace- We have deliberately set- ourselves to catch that water by putting in porous .shafts up to the surface.”

The journey proceeded in an upstream direction directly below the crack that developed nearly two years ngo. The gallery was perfectly dry, except tn one place where a tiny trickle of water percolated through the breccia.

“That,” said the engineer, "is part of thie crack!. Switch on the torch and you will see the filling of concrete that was forced down under pressure from the surface. We are 140 ft. underground, yet the concrete has been forced down here all ‘the way from the top. That trickle is nothing. It does not -come from the headrace, but from the .surrounding country, which has been .soaked by the recent rains. When ifc stops raining there will be no <sign of a trickle.’’ WONDERFUL GALLERY SYSTEM.

An opening aloft suddenly came into view. Looking upward, a tiny circle of daylight gleamed out of the darkness. It was the opening of one of the two great shafts, 150 ft. deep, connecting an elaborate .system of inspection galleries which run at right angles to the headrace near the point where the headrace lining commences. Every 40ft. up a gallery branched away from the shaft, enabling a minute examination to be. made, at varying depths, of an entire cross-section of the country beneath the headrace.

With a “Watch your step!” the engineer commenced to climb the. iron rungs embedded in the concrete lining of ’the -shaft which took the place of a ladder. It seemed like 10 minutes before the firsii gallery was reached. The bed was a dry as a drawingroom carpet. So was the bed ot the gallery above, only 40ft. under the water.

"That shows that not a drop of water is coming through the tih'.s that line it hr headrace,” said the guide. “Now let’s get back.’’ On the return several diversions were made and three times the travellers came out into daylight in the gorge through openings in the cliff. Under the falls the faintest rumble overhead indicated '.he spot where the water was 'tumbling ov. r a crest—a somewhat forbidding sound to the visitor, but all in 1 lie day’s work lor the engineer. On rhe way out •they stopped to look alt the glow-worms which are gradually making a new home I<r Ibemsi Ives in the tunnels. As the lock of the tunnel gate clicked behind him the guide consulted his watch. It was 3 p.m. The journey had occupied over two hours. ■tarn wntaitiMMiuJHß*