Mr. Blackett's Report on the Harbor Works.

Hawera & Normanby Star, Volume X, Issue 1917, 30 April 1888, Page 2

Mr. Blackett's Report on the Harbor Works.

{Continued.)

(united press association.) WELLINGTON, April 26. Had the weather of the past 12 months been of an ordinary character, it is doubtfut whether the sand difficulty would have yet made its appearance, but an almost uninterrupted course of strong westerly and south-westerly winds has doubtless precipitated the result. As an evidence of this is may be stated that in the opinion of the engineer to the Harbor Eoard it would not have .been possible to have constructed more than one or two 18 feet sections of the breakwater during that time had it been desired to do so. The first appearance of the sand beyond the end of the breakwater was in September, 1887, and since then the formation of the spit has been continuous and is still slowly progressing, the rate of progress depending on the direction and force of the wind and sea. As before said, these have been such as to accelerate the formation of the sand spit. As far as this has already extended, it is of very slight detriment to the easy and safe navigation of the harbor, but should its growth proceed at the same rate as heretofore it will at no very distant date render it difficult for vessels to enter or leave the harbor with ease or safety in bad weather. To avert such a contingency, it will be necessary to prevent the further passage oi sand around the end of the breakwater, and this can be temporarily secured by the construction of a groin, or wall, to connect the island of Mikotahi with the mainland, which work could be performed at a moderate cost, and should at once be undertaken. This work would have the practical effect of interposing a barrier of about 900 feet long against the movement of the sand (that is, 450 feet of artificial work and 450 feet of the island itself). But there is little doubt that the sand would still find its way round the end of the islaud, and a further means must be sought by which, after this minor work is done, a complete stoppage of the sand could be effected. This could he accomplished by a prolongation of such groin, or wall, beyond Mikotahi to the Lion Rock — a distance of about 1400 feet — and eventually from thence to Moturoa, a rocky island about 1500 feet further, thus making a protective groin, including the island mentioned, of about 3000 feet long. Such a groin would form a complete barrier against the movement of the sanJ, and would indefinitely postpone the occurrence of any further trouble from such a cause. The groin between the islands would rise from the bottom to about water level, and would be composed of heavy rock work tipped trom a staging. It would have the additional effect of sheltering the breakwater itself from heavy seas rolling in from the west. I have made an approximate estimate of the cost of the various works numerate J as follows, viz: — 1. Erection of rubble stone groin, or wall betwpon the blockyard and Mikotahi, including the laying of a line ot rails to connect with the present line leading to the quarries, —£1000. 2. Construction of heavy rubble stone groin from Mikotahi to the Lion Rock, including road and line

around Mikotahi, staging, etc.,

etc.,— £56,000. o. Construction of heavy rubble stone groin from Lion Rock to the island of Moturoa,— £lo,ooo. 4. Wagon stock, additions to cranes, etc., £4000; contingencies, say, £7000 ;— total, £78,000. Of the above items No. 1 is the first that should be carried out, and the work could he completed out of funds now in the hands of the Harbor Board, viz., £1838. The works under the heads 2 and 4, amounting to £60,000, might be spread over several years, say for the year after No. 1 is completed £10,000, and for each succeeding year say £6000 to £8000 until the gap was closed up to the Lion Bock, the work between which and Moturoa would be undertaken only if iound absolutely necessary. The effect of this work should be well watched as it proceeded, as it might be found that a partial closing of the gap would answer the intended purposes,' and thus save further expenditure, or, at any rate, it might be found that a smaller expenditure per year would be sufficient. Further work would be needed in the removal of the sand spit already formed in the harbor, or as much of it as would permit of direct access to the wharf. This will not be a serious matter, as the Harbor Board has an excellent small dredge, which, however, needs a stronger crane than the one now fitted ; this could be supplied for, say, £250 to X'3oo, and probably a similar amount or a little more would secure all the necessary dredging. To summarise the results of my observations, I may say that at New Plymouth the Harbor Board baß expended on all workß a total sum of about £220,000. For this expenditure they have (besides certain plant and material on hand) an excellent harbor of moderate but good capacity, whero vessels such as trade between the provincial ports have every convenience necessary for loading and discharging while lying in Batety at a good wharf. It seems desirable that such a favorable state of things should in the interests of the country be conserved, and this can be done, as has been shown above, by the expenditure of a moderate sum of money per year, the funds being already available" for the first necessary piece of work, which should at once be undertaken. The importance of maintaining a harbor of such a character is great, and in my opinion would justify even exceptional measures to secure the necessary amount required per year. In conclusion, I most strongly recommend that this view of the subject

should meet with serious and favorable consideration. — I have, etc.,

John Blackftt.

Attached hereto is a plan, showing generally the features described in this report.