The Lyttelton Times. SATURDAY, OCTOBER 20, 1866.

Lyttelton Times, Volume XXVI, Issue 1823, 20 October 1866, Page 2

The Lyttelton Times. SATURDAY, OCTOBER 20, 1866.

The Provincial Engineer's report on the overflow of the Waimakariri is of a character to frighten the public of Christchurch very seriously. A natural dam formed by a bank of shingle, Mr. Dobsontellsus,hasbeen broken through by the late fresh at a point about 17 miles from town; and the only obstacle between the present main body of the river and its old bed, which comes down to Christchurch, has been thereby removed. Prom this time forward all the water which in a time of flood may rise above the temporary southern hank of the Waimakariri will make its way into the Avon. This is bad enough, but it is by no means all. The Provincial Engineer goes on to warn us that, though he does not apprehend any immediate danger of the main body of the torrent coming down this way, yet in a few years a considerable portion of the river must be expected to return to its old channel, and flow through Christchurch. Mr. Dobspn very emphatically warns the mill-owners on the Avon and its tributaries, that their properties are in great danger; aud in so doing he implies a warning, which perhaps he does not care to make more plain, to the owners of other property in lowlying spots, and situations contiguous to these streams. We do not suppose that the greatest danger to be apprehended goes any further. The general level of the plain—the greater part of Christchurch, for instancemust be out of all real peril, from the simple fact that the spread of water in the highest imaginable flood must be so wide as to seriously affect only the watercourses themselves and such depressions in the surface as may be reached by the overflow. Perhaps the most alarming part of the report, looked at as a warning to those concerned, is the calm equanimity with which the Engineer states that his best efforts must for the present be confined to waiting and watching. He hopes that the spring freshes this year will not do much damage: but whether they do or not, he cannot take steps to avert the danger during their continuance. We are at least glad to infer that all hope of devising protective measures for the future is not abandoned. Mr. Dobson is not sanguine of success, but at any rate he is not a pure fatalist on the river question ; aud we are glad of it. We have had too much of the theory that nothing can be done, and, therefore, that nothing ought to ' ■■> attempted. Even in the. very sei-iou ■ i;ase of the Kaiapoi Island tln-re haa been proof that opposition may be successfully made to the Waimakariri. That a simple embankment stood against the current, and did good service is a great fact. The best form of construction for'embankments and their proper position and extent may yet have to be devised; but there seems every reason to believe that even such rivers as the Waimakariri in a fresh may be restrained by 'artificial banks at the weak points, Justus effectually as they nre by natural banks in the rest of their course.

What we may call the "impossible" theory of fivers seems to us to rest upon fallacious grounds. It is argued hat the Btreum must flow towards the

sea along the natural dip of the surface ot the land, In the case of Kaiapoi Island, for instance, the Waimakariri must sooner or later change its course to a more northerly one, in obedience to this law, and cannot be prevented. In the case of the eruption above the old river bed, the same irresistible law is to bring the Waimakariri to the 'southward. But if the facts on which the theory is founded are fully ascertained, and we believe they are, they only prove that up to this time the river has not been flowing in obedience to the natural law which is declared to be irresistible. A bed of shingle here and a stiff clay bank there have sufficed to keep the river in check hitherto. And canuot art imitate the devices of nature ? It is too absurd to say that there exists a natural law which has not yet come into operation, but is to take effect from this time forth. The theory destroys itself. We are glad to find that Mr. Dobson does not prostrate himself before the Waimakariri in a spirit of fatalism, though we are aware from his often recorded opinions and acts that he approaches the question of river conservation with great reserve; and we can only trust that his experience and skill will enable him not only to protect Ohristchurch, but even to avert the calamity which so seriously threatens Kaiapoi.