ARAPUNI.

Hauraki Plains Gazette, Volume XXXX, Issue 5465, 23 August 1929, Page 2

ARAPUNI.

THE EXISTENT DANGER. FAULTY COUNTRY. Despite all statements to the contrary, grave danger threatens Arapuni— danger that has been known to exist practically from the putset of constructional works. The danger does not include the actual dam or spillway—they are as sound as Armstrong Whitworth’s reputation. The whole trouble lies with the composition of the surrounding country. Nowhere near any of the constructed works is there solid ground. Composite areas of rock are entirely absent, the majority of the terrain being merely a sort of <eompressed sandstone. Taking this fact into consideration when building the dam, Messrs Armstrong Whitworth flung underground concrete extension walls on either side of the dam for many feet inland ; but even those did not prevent the seepage of water. All was well until the tunnel was closed and the water diverted from its historical to pre-his-torical bed, across which, lower down, the spillway is built. Then the trouble started. Soon tiny trickles of water made their appearance at either side of the dam, insignificant trickles at first which soon grew to miniature rivulets 2ft and 3ft wide. Inside the dam the inspection chambers which honeycomb it were flooded, so that one could only descend a few feet down the manholes on the roadway. At the base ingress by tunnels was also pre vented, as a few feet in was water. The dive •’« ion tunnel, which is concrete lined, has once more been put forward as a palative to those who are apprehensive of danger. It has lately been said that in the event of any potential danger the sluice-gates could be opened and thus the waters banked behind the dam could rush through the tunnel until the water had reached its pre-dam level, which would leave both dam and spillway dry. The practicability of this is very much to be doubted. When the tunnel was first experimented with the behaviour of the ground above and around it caused doubts to be expressed as to the tunnels’s use as an emergency outlet. The ground shook and trembled, reminding one of nothing so much as a miniature earthquake. It was originally intended to maintain the tunnel ready for emergency for a short while and then fill it in for good. The tremulous nature of the ground, though, resulted in the opinion being arrived at that the sooner it was filled in the better. As matters are at present, even if the gates were opened ever so little at a time until the full force of the water was running through, the vibration caused by the terrific volume of water thundering underground would cause the disintegration and final collapse of the tunnel. What would happen then can best be left to the imagination. As for the spillway, directly below which grave danger now exists, the question of excessive erosion arose immediately after the water first reached its level and flooded over. The diverted river in its mad rush below the spillway took a course away altogether from the expected one carefully marked out by little white rags on sticks. It spread over quite a considerable area, tearing away millions of tons of the rotten terrain, to what effect was soon only too forcibly realised by those living in Hamilton and further down the Waikato. On the right bank, some little distance below the spillway, lay a large, deep pit wherefrom sand had been excavated, for the mixing of concrete. The gradually widening river came within an ace of entering this, and thus careering clean across to the gorge. Had that happened it is not pleasant to contemplate what the consequences would have been. As it was, the dividing bank was reduced to the matter of one foot. As the river continued on its new course it dug deeper into the soft ground, so that to the great relief of all concerned the waters receded and the river confined itself to a route more like the originally expected one. At the waterfall below the spillway great, danger also existed, but a knoll on the right which was composed of stouter stuff than the pumice conglomeration successfully withstood for some time the terrific force of the water. Then the back of the knoll gave way and the water poured around, making an island of it. Had the water been allowed to run the whole knoll would have gone the way of the other millions of tons to annoy Hamilton, clog Horahora, and silt up the Waikato. It was given no chance, however, and gangs of men working feverishly soon dammed the impromptu reach of the river. Now. however, the fact is admitted that even this bulwark of a knoll is threatened with disintegration; in fact, it is falling to bits already. It is also at last admitted that serious erosion is taking place practically at the foot of the spillway. Why not “the truth, the whole truth, and nothing but the truth ?” It is a deadly serious matter, and the country has every right to know the truth, whether ’t be distasteful oi' not. Coming events are more than likely to prove the good sense of a Labour member who, in the House, after a million pounds had been expended on the mad scheme, proposed the cessation of work with the loss of a million, instead of continuation with the consequent and ultimate loss of millions.

In an interview on Wednesday the Minister of Public Works said : “Owing to the dam and conversion works being completed, and the powerhouse construction being abandoned by the constructors, the result was that the whole flow of the river has been for over a year and a half passing down the old channel over the previously mentioned old waterfall site.”’ Why, in all truth, try and foist the responsibility and blame on Armstrong’s in a palpably weak excuse ?

The Minister said : “To explain the position properly, it was necessary to enter into a little explanation in order to refresh readers’ minds.” Then why

not in all fairness refresh ti e “readers’ minds” on both sides of the case, instead of leaving an uncalled-for slur on the original contractors ? Armstrong Whitworth abandoned the construction of the powerhouse on the grounds that the site did not come up to the bearing strength given by the Public Works Department engineers in the contract. The prophesied solid foundation was not encountered, and Armstrong Whitworth considered it a breach of contract on the* Government’s part. Whether as an excuse to get out of the contract or not, the Government knew Armstrong’s opinion on the subject, and their reason for not proceeding with the construction of the ' powerhouse at the scheduled time. Whoever is to blame in the matter it is for a commission to say; but that there is fault—grave fault—to be placed in some quarter is only too obvious, and not to be blinked at. Sooner or later the truth will out, whether by dire catastrophe or the further throwing away of millions in the endeavour to salvage a scheme rotten from the outset by the nature of the land.