PORT OF GREYMOUTH

Grey River Argus, 5 February 1930, Page 6

PORT OF GREYMOUTH

NEW IMPROVEMENT SCHEME By Foremost Scottish Engineer PROVISION TOR BREAKWATER HARBOUR. What may be destined to mark a now era in the history of the port of Greymouth was the report which th? Chairman of the Harbour Board, Mr Joseph McLean, last evening submit ted to the Board at the ordinary meeting. This report outlines a schem? quite new to the local Board, in the form of the construction of two curu ed breakwaters, roughly each of a length of between three and four Thousand feet. from the foreshore, at either side of the existing harbour entrance. These structures would, roughly speaking, be for their entire length a distance from the present walls of say between thirteen and sixteen chain. The object of their erection is succintly explained by the Engineer responsible for the scheme, Mr R. Gordon Nicol, 0.8. E., AI.Inst.C.E., Al.I. Mech.E., J.P., Harbour Engineer of Aberdeen, and Consulting Engineer to the Fishery Board for Scotland, who is regarded as perhaps the leading harbour engineer in Britain to-day. The Report

The following is the text of the report received by Mr McLean from Air Gordon Nicol, 0.8. E., M.lnst.C.E., M.l.Mech.E., J.P., Harbour Engineer, Aberdeen, and consulting engineer to the Fishery Board for Scotland:— Harbour Engineer’s Office, Aberdeen, 18th November, 1929: Dear Mr McLean. —Improvement of Greymouth Harbour, New Zealand: —Referring to our interviews in August and again ♦luring the last few days regarding the improvement of Greymouth Harbour. I have given the matter careful consideration and I beg to submit the following observations: — In considering the question of the improvement of Greymouth Harbour, New Zealand, it is impossible, without full local information and a personal study of the conditions, to put forward a detailed scheme for improving the harbour. I have, however, carefully studied the information which you have placed at my disposal, and the engineers’ reports and plans which you loaned me.

The problem is complicated by he existence of the Grev River, which is

a stream subject at times to intense floods carrying large quantities of detritus and also by the littoral drift of sand and shingle fnom south to north along the sea coast. The existing breakwaters are designed as training vyalls for the river, and these have been extended from time to time with a view to reaching

deeper water, as the combined action of river and sea has caused the deposit of material in the channel of the river, winch forms the entrance chan nel to the harbour.

The most probable effect of a further extension of the existing breakwaters is the reproduction of the existing state of affairs at a point further seaward than at present, and it is doubtful whether sufficient scouring effect can be obtained under normal conditions from the tint rush of tidal water from the river ami lagoons to provide for an in creased depth of water in the entrance channel. The littoral drift of sea, sand and shingle will tend to produce shallow water about the extended pierheads and to cause an accretion of material principally outside the South Breakwater, and the river will continue to bring down detritus which it will depos. t in the form of shoals in the entrance channel to the harbour. These conditions may be improved to some extent by controlling the flow of water in the entrance channel from the lagoons, but I am doubtful whether such betterment will be sufficient to improve the harbour entrance permanently. As the size of ships frequenting the port increases, requiring an increased depth of water en trance channel, these difficulties will become more acute. It appears to me that the harbour of Greymouth has now reached a stage in its development when further improvement is difficult along the present lines and when it is advisable to supplement the existing training works by the construction of seaworks designed to secure the entry of large vessels into the harbour in all weathers. I would recommend a policy of providing the harbour with an entrance which would afford easy access to shipping and off maintaining the required depth of water in the entrance channel principally by means of dredging. T,o provide for the requirements of navigation it is necessary that the entrance to the harbour should be in deep water. that the entrance should face the direction of the worst seas, that it should be sufficiently wide to admit of the entrance of vessels of the largest size likely to use the harbour and sufficiently narrow to exclude storm waves as far as possible, and that immediately inside the entrance an expanse of protected water should be provid ed to reduce the storm waves passing through the entrance. Keeping these principles in view I would put forward the I

following outlines of a scheme of seaworks for Greymouth Harbour. The scheme would provide for the construction of two long curved breakwaters extending from the foreshore, one on each side of the existing harbour entrance. Those breakwaters would leave an <ntranee of about 800 feet in width at low water level, the width of rhe entrance being reduced at the sea bottom by the slopes of the breakwaters. They .might be formed of heavy rubble mound construction, and I understand that there is an abundance of stone in the neighbourhood, suitable for this purpose. I consider that the South Breakwater is the more important of the two and that its construction might be carried out in advance of the North Breakwater. The two breakwaters would enclose a large additional water area'outside the present, piers, and this area would form an effective stilling basin so that vessels entering the harbour would have no difficulty in passing between the existing pierheads.

T have prepared a sketch plan, on which J have indicated suggested lines for the two breakwaters, and 1 send you duplicate copies of this. The problem of maintaining the depth in the entrance channel would be met by dredging material deposited by the river, probably by means of a suction dredger. The depth of water in which these breakwaters are constructed would be sufficient to prevent filling nt the entrance due to the action of the sea. 'Die littoral drift along this coast would tend to an accretion of sand and shingle outside the South Breakwater, but I do - not anticipate that the deposit would encroach on the entrance channel to the harbour to any appreciable extent. A study of the problem on general lines and with the information which T have does not seem at present any more satisfhdt ory solution than the one I have outlined. The plan which T have prepared is in the nature* of an outline plan and before estimates or working drawings could be prepared it would, be necessary to have careful surveys made of the harbour entrance and a study of local prices and conditions.

If it is. considered that such a scheme is unwarranted by the prospects of the trade of Greymouth and it is necessary to consider alternative proposals, T do not consider it advisable in the interests of navigation to reduce the existing width of the entrance between the pierheads. The improvement of the lagoons by dredging and the utilisation of the water flowing out of the river and lagoons with the ebb tide will help to scour the entnance channel, but I am of opinion that the channel will always require a considerable amount of dredging to maintain its depth. I have not dealt with the internal development of the harbour. T under stand that the existing wharfage is sufficient to deal with the present trade of the harbour. It appears to me that future extension of wharfage when required might be provided by converting a portion of the lagoon area south of the harbour into a dock with an improved entrance from th” /ver on the site of the present outlet from the lagoons into the river.—l am, yours faithfully: (Signed) R. Gordon Nicol, Harbour Engineer.

The report was accompanied by the following covering letter:— Dear Mr McLean, —T am sending you a statement of my opinion upon Ihe improvement of the Greymouth Harbour in the form of a letter ano I return, under separate cover, the Reports and Plans which you left with me, as follows:— Reports: Greymouth Harbour. Report by Wm. Ferguson. M.lnst.C.E., F. W. Furkert. M.lnst.C.E., and J.' Blair Mason, February. 1925; Greymouth Harbour Board. Report on the Harbour Works by C. W. Darley, M.lnst.C.E., 3rd March. 1913; Greymouth Harbour Board. Report on the Harbour Works by R. W. Holmes. M.lnst.C.E., sth August. 1907 and 22nd Xugust, 1910, and J. Burnett, M.lnst.C.E., 23rd August, 1910; Greymouth Harbour. Report on the conditions of the Port and Works by C. Napier Bell, M.E.Inst.C.E., 1900; Greymouth Harbour. Report on present conditions and future requirements by C. Napier Bell, C.E.. and W. TI. Hales. C.E., 22nd June, 1895; Report on the Greymouth Hartfour Works by Sir John Goode. C.E., December, 1879 to accompany W. H. Hales’ and C. Napier Bell’s Report; Greymouth Harbour Board, Annual reports and Balance Sheets, 1926 and 1927; Greymouth, Book of Views.

Plans: Greymouth Harbour and Westport Harbour, Blue print of Westport Harbour; 'Greymouth Harbour, Drawing Nos. 1,2 and 3; Set of 1 blue print and 3 drawings to accompany Report, by Messrs Ferguson, Furkert and Mason. Map of coast line of New Zealand adjacent to Greymouth. Blue print of Greymouth Harbour to accompany Report by Sir John Goode. I have retained one copy of the Report by Messrs Ferguson. Furkert and 'Mason as you loft two copies with nie. T trust that you will find the views expressed in my letter helpful in considering the question of improving Greymouth Harbour. If there any points upon which you would like further information, I shall be glad to add what T can on hearing from you. I send you a copy of the Annual Recounts of Aberdeen Harbour, for year ending 30th September, 1928, which you will find of interest. —With kind regards. 1 am, yours sincerely: (Signed) R. Gordon Nicol, Harbour Engin-

In presenting the report, Mr McLean c aid that he had been extremely fortunate in securing the services of Mr Gordon Nicol, who was recognised as bne of the leading harbour engineers of the world. He felt sure that one and all would like to see the harbour improved. He also was sure that this scheme was a practical one. He had,

in fact, shown the scheme to the En gineer in Chief, Air F. W. Furkert, who had been considerably impressed by it. Roth the Engineer in Chief and the i Board’s own Engineer Air Johnston, I had studied the scheme, and they wer? vach of the opinion that it could be done out of revenue. It was only the fact that it was from a national standpoint that he had been able to interest Air Nicol in the matter and to se•cure his scheme. Air J. W. Greenslade said that the discussion that evening was' but a preliminary to this question. In his position as Mayor, he would certainly extend his congratulations to Air AleLean for taking such an interest i»i the welfare of the district, and securing the report. Every consideration should be given to the scheme, an t, 'although it had been suggested in a paper that Mr McLean should be accorded a vote of thank*, but that the Board proceed along tho same lines as 'they had done before, he (Air Green slade) felt that this report should be considered in its entirety. It would ’be everyone’s wish that the scheme would prove a practical one, but even 'if it did not, the fact remained that Mr McLean, in securing it, had done his very best to further the welfare of the district. Air Greenslade then moved that the scheme be referred to the Engineer in Chief (Air Furkert) and the Board’s Engineer (Air T. A Johnston) to make, a report upon it the Board to bear the cost of such preliminary investigation. In seconding Mr Greenslade’s motion, Air G. E. Perkins also extended *his hearty congrtaulations to Air McZLean upon obtaining such a concise and such an emphatic report. The Chairman deserved the approval of all by his public-spirited action in obtaining the report at his own expense. Mr D. Tennent also congratulated Air AfcLean, but stated that, in his opinion, the Board could not overlook the fact that it had the opinions of three other prominent New Zealand engineers aS to the improvement of the f bar.

Air McLean then thanked the mem piers for their eulogistic remark?, and ’he at the same time suggested that Air Nicol should be thanked for the interest which he had shown in their port by preparing the scheme. The Chairman’s suggestion was greeted 'with approval by the members.