OVER DIVERSION WALL

Poverty Bay Herald, Volume LXIII, Issue 19023, 25 May 1936, Page 3

OVER DIVERSION WALL

HARBOUR SILT DISPOSAL GREAT SAVING OP! TIME BOARD CH AIR M A N'S PLAN A proposal that the board should arrange I'or the disposal of .-ill dredged out of the Kaili "basin by tin' dredge A.C., by pumping it over I lie training wall iiiro the diversion cut, was put before members of the Gisborne Harbour Board to-dnv by the chairman, Mr. J. Tombleson, who pointed out that an immense paving of nine could b,e made by eliminating the effects of bad weather upon rlie operations ot the maintenance dredge.

The outline of Mr. Tombleson V proposals was given in the following report : "The board's dredger A.C. is doing excellent work, ami the new style Priest man sand-grab i.-- giving good results.

'"l'lic present transport method ot lowing out and back is, I think, faulty, because it is uneconomical, and I ask the board to consider as an alternative the idea of disposing of the dredged material by pumping or otherwise discharging through the training wall above Hood level into the river.

"Towing has several disadvantages, taking never less than one hour even when close to the entrance where hie sand channel is now being widened. When work starts in the basin it will be nearer two hours, and I see no hope of continuing two run loads per day with the longer html. The barge itself is unwieldy and very bad to steer, and to remedy this to some extent, she carries permanently several fathoms Of heavy cable so as to put her down by the stern, and for the same reason and purpose the forward grab stops working some time before the other. These precautions mean loss of weight each load and add up in the course of a week. "In a strong westerly, the board's Launch requires, and will continue to require, assistance to clear the entrance This i,- an added cost. CONDITIONS OUTSIDE GROYNE "The most serious disability with regard to towing and the greatest loss to the board lies in the fact that in any average year there are a number of days when the. dredger could work inside, but owing to conditions in the bay could not go outside to unload. The harbourmaster estimates the number of these days at lOC per annum. Dredging operations are always carried on with the foregone expectation of considerable lost time through adverse weather conditions. L'his was so with the Maui and Korua, and ;we expected no better with the A.C, but J have felt from the start of the new work that this ought not to be taken I'or granted, and that the fact of the A.C. having no solids to pick up made the problem much easier to solve. The river as a dumping ground for our spoil lies only 1811. away from our dredging area," and there is only the, handicap of the wall. "On the start of the present dredging operations'. 1 mentioned the- matter of the lost days and my idea that it ought to he feasible to discharge into tin; river, to the harbourmaster and the dredgemaster, asked lor their advice ami alter several conversations this report is Lhc rosult. The harbourmaster thinks we might expect to discharge three loads instead of two per day and that the saving of tiic hundred or so days per milium is without, question. As tiiis idea will, it approved by the board, be altogether a new departure in our method of transport, and may lead in flic first place- to considerable expense in installing a motor pump and power line connections, 1 advise that both works and finance committees be asked for a. careful and detailed report on the. whole matter. "In actual operation the scheme would work as follows: The dredger would load her full 4C(J lons, bring if alongside the training wall near to. but not. masking, the slip. The question of cost as againsl saving of time lhen comes in for consideration. She could with no expense except that of making a sloping platform for each crane, drop a load at each plat form and pick it up again. If a motor and sand pump arc favoured and installed on lhc wall, Iherc are tit least two methods to consider—either pump out of the hoppers or *lrnp the load and pump .iff lhc floor while the dredging continues." COST 01'' LOST TIME, Introducing his report, the chairman pointed out that the cost of lost time in dredging, with men standing by, was estimated at at least £3f)o per annum. He thought thai the board should ask the finance and works committees lo go into lhc project thorough I v. Mr.' M. T. Trnlford seconded the chairman',- motion to refer the project to committees for investigation, lie said, thai there would be heavy capital charges involved in the scheme, and that it would need careful considoral ion.

Mr. A. .1. Ni.-ol slated thai he did not. object lo having the commit tees consulted, but he was not favourable to the proposal advanced by the chair man. Certain losses of time were inevitable in dredging, and he did not consider that a saving of .Clod would cover the capital charges involved by the chairman's scheme.

Messrs. George Smith and T. Corson considered that the hoard could not hope to effect any great saving. .Mr. C. 11. Williams argued that these considerations could bo taken up by the committees, which should have an opportunity of dealing with the plan. Mr. !\ E Wilson supported this view. The possible saving of 100 days dredging, together with the depositing of an extra load per day, should be worth while, he felt. Mr. I. .1. Quigley considered that whatever other benefits might be secured, the board -could not hope to deal with an extra load of spoil per da v.

The chairman's motion was carried, and the matter was referred lo the committees.