THE OTAGO HARBOUR.

Otago Daily Times, Issue 19904, 25 September 1926, Page 11

THE OTAGO HARBOUR.

TO THE EDITOB. Sir. —The Dunedin Harbour Board is composed of ns clover a set of men as Dunedin can produce, and in consequence I suppose thev will resent anything an outsider may toll them. 'VV oil. a little knowledge is a dangerous thing. I notice that the board sent a deputation to Wellington to interview the Government about a survey of the East Coast of the South Island. If' it would look up the early history of New Zealand it would find all the survey it needs. 1 wonder if it ever occurred to tho members to inquire why there are only 4ft Sin rise and fall of the tide at the Dunedin wharves and 2ft more at Lawyer s Head and 13ft at tho Auckland wharves. The same land and the same sea: why the Bft difference? If wo had Bft more water in our harbour, it would make a wonderful difference. Now, there must be some good and sufficient reason for this difference. Lot us see the reason. Why, tho bottom of the ?ea under the water is somewhat like the land above the water: it, is coinnosed of hills and valleys, gorges wider and narrower in places, through which the currents flow more or less rapidly according to the width and depth. One such channel site is in the neighbourhood of Svdnev. .and passes along the coast of the South Island, very close to the Otago treads and exhausts itself in the neighbourhood of Stewart Island. This is proved by tho fact that logs of cedar that are washed down the New South Wales rivers are picked up at Stewart Island. I have purchased some of these logs and that, when cut up. they were not affected bv salt water, this proving that they had been a very short time in tho sea. It is also found that outside tho Heads no bottom can be found, not because there is none, but because tho current is so strong that it carries off the sinker and also carries off the incoming tide, and Dunedin gets only the back-wash which amounts to 4ft 9in. Now. the question is how to harness this strange current. Everyone is agreed that current is what is requued in our harbour, sufficient to scour tbo sand out of tho channel. Now. let us profit by what others say and do. Recently we had a report from Captain M‘Donald. in which ho said that at one time tho peninsula had been a separate island, and that the water there was very doop, thiat it had been filled in by drifting sand which connected it to the mainland. It is also reported that Captam Cook sailed through. To my knowledge, a road has been driven down 60ft in the flat and no bottom found. Let us keep these things in mind and profit by what our neighbours have done. Quite recently it was published that 50 years ago there was a considerable loss of life and shipping at Timaru. I remember the occurrence. The Harbour Board there decided that if it was going to make Timaru a safe harbour it must build a protection wall. Therefore, it drove two rows of piles and laid a railway far enough out to stop the oction of tho sea and prevent the gravel from washing in. Large blocks of stone were quarried and tipped on both sides of the railway, thus making a double barrier tho same as at Now Plymouth. Now. then, for our scheme. Lawyer s Bead has the stones required on the spot. Why not copy Timaru and carry out a double rock wall to arrest the sand that. Captain M'Uonald says comes from tho Soullnand rivers and creeps along the coast and is washed in at tho Heads and is lodged m the channel without sufficient scour to carry it out. When that is done, then put the present and the proposed now dredge, one at each end. and dredge out this sand 25ft or 30ft below low water. With the Southern Ocean continually scouring, you would not only clean out the channel out tiio whole of the harbour and make it equal to that of Wellington, I should say that tho course of the canal should bo up through Anderson’s Bav and straight through Tainui to Lawyer’s Hoad, the land all along, which would become very valuable. being reclaimed. The sea would reclaim St. Clair half a mile nearer White Island, which would become tho property of the board. There would bo ymic minor difficulties, such as property to acquire at Tainui, but after tho reclamation had been done, it would be worth much more than it would cost. There is tho drainag outfall, which could be syphoned under the channel or put in a septic tank, as it should have been at the first, there will bo some bridges on roads, but I can see no difficulty in the way. To those who can remember. there was a company in London some 50 years ago which offered to take over the board’s endowments and do this very thing at no other cost to Dunedin. Of course it intended that the entrance to Dunedin should be from Lawyer’s Head, not from Por-t Chalmers. Why not? 1 think I hear someone saying: Yes, block up the harbour at both ends with sand. Not so. lot us profit bv the Auckland Harbour Board’s operations. This board drove rows of concrete piles—some of them Jtfft long and braced them together, and made concrete reinforced slabs 10ft or 12ft square. 6in at the outside and 9in in the centre. These were nut at tho back of tho piles and in between the braces which kept them in their places and, as the material was dredged from the front and lied in at the back, these slabs sunk ,wn to the bottom and prevented what, in our case would bo the sand from getting into the channel. This would only be required on one side,—the rock would be on the other side. Were this done it would cost some money but so does continual dredging, and the land reclaimed would pay for the whole of it. Besides Dunedin would have a harbour as good as its neighbours, its shipping would be assured. 'I here is much more that could be said. hut. this letter !■; alreadv 100 long.— i am, etc., Duxedinite.