The Times. Published on Tuesday and Friday Afternoons. Motto: Public service. TUESDAY, SEPTEMBER 14, 1920. THE WAIKATO RIVER.

Pukekohe & Waiuku Times, Volume 9, Issue 566, 14 September 1920, Page 2

The Times. Published on Tuesday and Friday Afternoons. Motto: Public service. TUESDAY, SEPTEMBER 14, 1920. THE WAIKATO RIVER.

In view of the great importance 61 the meeting to be held in Mercer next Saturday afternoon we make no excuse for devoting our leading columns once again to the subject of the improvement of the Waikato River for navigation and land drainage. That meeting will probably provide the last opportunity for some time for those interested in this great waterway urging their views upon the Government, and demanding that the promises made by numerous Ministers shall be given effect to. The promised reinstatement of the Inland Waterways' Commission will afford an opportunity for enquiring into the complicated but not unsolvable engineering problems connected with improvement, and if the Government can be induced to accede to the very reasonable proposal that this should form the first portion of the commission's labours, there would be a chance that the work might be done in a reasonable time. Otherwise we see no hope of anything being attempted for many years. The Waikato River possesses certain characteristics which make it unique among the rivers of the world. In the first places its real estuary is some miles inside its mouth. In the second place its t-rue bed is from forty to sixty feet below the level of its apparent bed, and consequently the same distance below sea-level. This is undoubtedly due to a subsidence of the land, for no river could have gouged out its bed to such a depth below low-water mark. A proof of this is to be seen in the tributaries which join it in the last third of its course, some of which are more than twenty feet deep, with hard clay bottoms. They made their beds when the land was much higher than at present, and, carrying no sand themselves, they have sufficient current to prevent the ingress of the riversand. It is this subsidence that accounts for the stumps of trees being formed "in situ" below sea-level, a fact that has puzzled some observers. In the third place the Waikato carries down vast quantities of sand, a conservative estimate placing the amount at two million yards annually. And lastly there is practically no fall in the last thirty miles Qf its course. That is to say, high-water mark at the mouth and mean summer level at Mercer are the same. We are rather Surprised at this advanced stage of the discussion to hear that some people believe that the river-bar is an obstacle to the navigation of the •Waikato, and to seriously advocate that steps should be taken for sweeping it further out. The bar is a good one, with thirteen feet of water on it at low tide, and can be safely left out of our calculations in dealing with the question of navigation, especially as it would probably cost some millions to remove it. No one expects to make the Waikato navigable for sea-going craft, and if a channel can be provided with a minimum depth of three feet it will amply meet requirements. It is not impossible, nor should it be very expensive, to secure this. Forty years ago the Waikato possessed such a channel, and people often express surprise that it has lost it, and we have even seen it suggested that the Tarawera eruption was the cause. The real reason is not far to seek. While the country was covered by its natural growth before the Waikato plain was settled sand only found its way into the river-bed in extremely limited quantities, and the river had little difficulty in carrying it out to sea. Now every drain, every road, every ploughed field and every cuttletrack between Lake Taupo and Ngaruawahia contributes its quota, and the river is unable any longer to dispose of it, unaided. To give it the necessary amount of training and assistance to restore it to the condition it was in, say, I87">. is the problem that confronts us.

The experiments that have been already tried have been more in the direction of lighting against Nature rather than of coaxing her aid to us The Kiver Board directed its energies toward the impossible task of lowering the surface of the river by four feet at Mercer. From the first we pointed out the impossibility of this Scheme, and several years' work and the expenditure of much money have shown how completely we were justified in our attitude. At no point has the river been lowered by an inch, but a long reach above Kaita-J ngata has been permanently raised. I

From tho first we advocated the training ftf the summer flow only, by a system of low groynes that would confine the current t<> a defined channel, but allow every freshet to get clear away over them. Floods we shall always have, and the more the swamps are drained and the buah cleared the faster they will eome

down to the lower reaches, and our aim should be to let them get to sea as rapidly as possible, not bottle them up as we do now. Mercer must always be subject to inundations, but a moderate expenditure guided by common-sense will prevent the floods rising so high or remaining up so long.

Rivers are notoriously kittle-cattle | to deal with. No exact engineering formula can be laid down "for dealing with them. Each of them has its own unsuspected traits and idiosyncrasies which can only be discovered by a long and intimate acquaintance with them, and the Waikato is probably as freakish as any of them. The French engineers, who appear to have been the most successful of any in dealing with rivers, and who claim to have established the exact radius of the curve at which running water makes the best | use of its fall, agree in saying that in dealing with them we must always expect them to do the unexpected. It is for this reason that we have always advocated that the control and management of the Waikato should be handed over to a body with a settled tenure of office, giving them time to watch the results of a series of carefully conducted experiments in the direction of teaching the Waikato to clean out its own bed. Tf money were no object it would be quite practicable to dredge out a channel and keep it dredged, but as the enormous sums required are not likely to be forthcoming all that can be done is to try and persuade the river to help itself. Only such a body as we have indicated will be able to do full justice to the great interests involved in the solution of the problems confronting successful land drainage and navigation, and we trust that next Saturday's meeting will prove to be a step in the direction of having it set up.