THE HARBOURS OF NEW ZEALAND (REPORTS ON, BY SIR JOHN COODE, C.E., TOGETHER WITH COPIES OF DRAWINGS). [In continuation of E.-9, 1880.]

Appendix to the Journals of the House of Representatives, 1881 Session I, H-19

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1881. NEW ZEALAND.

THE HARBOURS OF NEW ZEALAND (REPORTS ON, BY SIR JOHN COODE, C.E., TOGETHER WITH COPIES OF DRAWINGS). [In continuation of E.-9, 1880.]

Presented to both Houses of the General Assembly by Command of His Excellency.

GISBORNE, POVERTY BAY (TURANGANUI RIVER) Bin, — 5, Westminster Chambers, London, S W., December, 1880. I beg now to present my report upon the works which I have to recommend as best adapted for the improvement of the Harbour of Gisborne, in Poverty Bay The coasting trade of Gisborne is at present carried on partly by steamers, which call and discharge and take in cargo whilst at anchor in the bay, and partly by small vessels drawing, for the most part, from 6 to 8 feet of water, which latter, notwithstanding the smallness of their draught, frequently experience great difficulty in effecting an entrance into the Turanganui, owing to the general shallowness of the bar and the narrow and tortuous character of the channel. The normal depth over the bar is only from 3to 4 feet at low water of spring tides. As the rise at springs is generally only from 4 feet 9 inches to 5 feet, it is obvious that the river in its present condition is not accessible by any other vessels than those of the smallest class of coasters, and by these only at the time of high water. It is true that the depth on the bar is subject to occasional improvement by the scouring action of floods, but any benefit so gained is but of comparatively short duration; having regard to the surrounding conditions it could not well be otherwise. An example of such improvement and subsequent loss of depth is given in the " Notes " by Mr T Perham, an assistant engineer in the Public Works Department, who made the survey for the purposes of this Report. Mr Perham states that, at the time of completing his survey, 2nd May, 1879, there had been no flood in the river for three years, but after a flood, lasting from May 3rd to Bth, the sand was scoured down to the rock (papa), the bar being forced out to about 10 chains from its former position, with 8 to 9 feet at low water. He adds : " On 24th June I again took soundings, and found the bar working rapidly back to its former position, with from sto 6 feet at low water . Calling at Gisborne on 20th August, I again sounded and got from 3 to 4 feet on the bar, which had then shifted in to about 4 chains off the edge of the western reef." This is precisely analogous to what occurs elsewhere under similar conditions, and I may here state that there would be no possibility of keeping down the bar at Gisborne without the construction of very long and expensive breakwater piers on each side of the entrance; but in this case there is the further difficulty arising from the presence of a ledge of papa rock at 3 feet below low water, immediately in the entrance. The precise extent of this papa is not defined by the sections; but, from general indications on the plan and sections, I have not the slightest doubt that it extends at a depth of somewhere about 3 or 4 feet below low water for a considerable length seaward of the entrance. Having regard to the physical conditions in this case, as above described, I have arrived at the conclusion that it would be altogether inexpedient, at any rate under the present circumstances of the trade of the district, to incur any expenditure in an attempt to improve the entrance of the Turanganui and the channel within, otherwise than on a very small scale, because I feel convinced that the results would not justify the outlay If harbour accommodation in the ordinary sense of the word —by which I mean a harbour haying such a depth of water as would admit of coasting and intercolonial steamers and sailing 2—H. 19.

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vessels entering or leaving and lying afloat at all times of tide, and properly sheltered in all states of weather, with adequate quay accommodation—is to be provided at Gisborne, the proper course will be to construct such works as I have shown by red colour in general design on the accompanying Drawing No. 1, and in detail on Drawing No. 2, and more particularly described hereunder. Works of Improvement Having regard to the great extent of sandy beach within the bay—extending, in fact, for several miles to the southward of the town and river entrance—and also to aspect and exposure of the bay itself, I am unable to recommend any solid structure between the shore and the line of three fathoms at low water, feeling assured, as I do, that a serious amount of sanding up on the inner or western side would inevitably follow, and to an extent that, to say the least, would be highly prejudicial to the present river entrance and to the utilization of the new work. By referring to Drawing No. 1, it will be seen that I propose to commence the external works at the point A, about fifty yards south-east of the salient angle of Maori Point, and to run therefrom in a south-west direction for a length of 550 feet as a solid structure, or root, shaped in plan as shown on Drawing No. 1 The sides of this root would be formed by substantial walls of rubble masonry, set in cement, founded on the bare papa rock ; this work, being about 120 feet south-east of the " Boat Harbour," would not interfere with that useful little creek. From the outer end of the root, and in a similar direction, I would construct an open viaduct of 1,410 feet in length, consisting of wrought-iron piles, supporting a deck formed of three rows of longitudinal wrought-iron girders, with proper cross girders and joists to carry the timber deck, the level of the latter being at least 15 feet above high water of ordinary spring tides. This viaduct will allow the heaviest seas to pass through and underneath it, with almost undiminished force, and, consequently, will insure such an amount of agitation and circulation as will prevent the deposition of sand in the vicinity of the entrance to the river, and shoreward of the proposed outer harbour As already explained, were a solid structure substituted for this open viaduct, the shelter provided thereby would inevitably conduce to the filling up with sand of the bight north-west of the work itself. From the outer end of the viaduct I propose to commence a solid breakwater pier, consisting of concrete blocks of about 22 tons each, placed in position by a portable overhanging setting machine, travelling outwards as the pier progressed. These blocks would be founded on bags of concrete, in the manner shown in detail on Figures 4 to 7 inclusive, Drawing No. 2. The inner portion of this pier would extend the viaduct in a south-west direction for a length of 500 feet, bending thereafter towards the north-west by a curve of 300 feet radius, the outer portion bearing W. by S. The quay surface of this pier would be 25 feet in width, and protected throughout on the seaward side by a massive parapet, also of concrete, a " bull-nose" course being provided to throw off the sea during gales. The level of the roadway on the root would vary from 9 feet 6 inches to 15 feet, the latter being the level of the viaduct deck, as already described, the ascent being made by a gradient of lin 100. The coping of the solid pier would be 8 feet above high water, or 7 feet below the deck of the viaduct, thereby necessitating an incline, which I have fixed at 1 in 50, to join these two levels. It is requisite that the viaduct should be kept at the height proposed, in order to raise the deck above the heaviest seas, whilst, on the other hand, the level shown for the surface of the pier will be more convenient and economical than if at a higher level. Figures 4to 7, Drawing No. 2, show the pier as a solid structure throughout. It will be seen from Figure 1 of this sheet that this work, shortly after leaving the end of the viaduct, would pass over the Pinnacle Rock. At this point, level benchings for the reception of the blocks would be formed around the Pinnacle by bags of concrete, in the manner indicated. Seaward of this rock the footings of the pier would be protected by an apron of concrete bags, arranged as shown on Figure 7— i.e., for such length as may not be founded on the bare rock. From the western termination of the pier I have shown a West jetty, of 300 feet in length, running N.W by N., with a return 120 feet long in a N.E. direction. At the eastern or shoreward termination of the pier I have laid down an East jetty, of 350 feet in length, in a NNW direction, with a kant 80 feet in length pointing S.W. The distance between the terminations of the proposed East and West jetties is shown as 560 feet. The jetties would be formed of cribwork, of the character indicated on Drawing No. 2 — i.e., of piling and stronglybraced timber framing, filled with a hearting of rubble stone. The heads of the jetties would in each case consist of a mass of Portland cement concrete. The total length of sheltered quayage provided would be 1,600 feet, having a depth varying from 21 to 30 feet at low water of spring tides, the rise of these tides being taken at 5 feet. A light would be provided at the head of the concrete pier, and a small port lantern fixed at the termination of the West jetty The viaduct has been proportioned so as to adapt it for carrying the 22-ton concrete blocks required for the construction of the breakwater pier Railways on the colonial gauge, so that they might be connected with the Government system, would be laid down throughout the works. Sufficient information is not available here to enable me to determine, with such certainty as is desirable, the line of approach road which it would be requisite to construct from point A, at the shoreward end of the works previoudsly escribed, to the town, including a bridge across the

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river. Before this can be done, a special examination of the site would be requisite; but Ido not gather that difficulties of any moment would arise in the execution of a satisfactory line of communication between, say, Gladstone Street and the root of the external works at Maori Point. I estimate the cost of the before-mentioned external works as follows :— £ Masonry root to viaduct, 550 feet in length 10,750 Iron viaduct, 1,410 feet in length . 48,980 Breakwater pier, 900 feet in length 135,180 West jetty, 430 feet in length, measured along the outside 30,790 East jetty, 430 feet in length, measured along the outside 20,700 £246,400 The above amounts include contingencies, and the provision of the requisite plant; they are based upon such prices as I believe would be found sufficient, having regard to my experience ox the prices applicable to other New Zealand harbours; although the local rates upon which the prices have been based are taken as much lower than named in the schedule attached to Mr. Perham's memorandum, to which I observe that Mr Blackett has appended a note that he considers the rates given " to be rather high," in which I concur. The works described, if carried out in their entirety, would afford very perfect accommodation to the steamer and other trade ; but important benefits would arise from the execution of the root, viaduct, and pier, omitting for a time the erection of the East and West jetties, in which case the expenditure on the three works would amount to £194,910. Unless this sum can be appropriated for external improvements at Gisborne, it is not advisable that they should be commenced. Internal Works. With regard to the question of improvements in the river itself, near the town, I may say that the conditions of the site are such as would not, in my opinion, justify the outlay that would undoubtedly be required to produce satisfactory results. For instance, a half-tide training bank would be required on the east side of the channel, and for its whole length, in oi'der to concentrate the currents in connection with the breastwork and wharf proposed by Mr Drummond, the Town Engineer. With respect to the design for the breastwork, described in the specification and shown in the drawing sent to me from the colony, I may remark that the structure contemplated in these documents would need to be considerably strengthened if it were at any time determined to carry it into execution. Mr Perham has called attention to the fact that during floods the waters from the Waimata " head " back those from the Taruheru. If considered expedient, this might be remedied by the construction of a V-shaped tongue from the point of land lying immediately at the junction of the two rivers, and, in connection therewith, the removal of the wharf and salient point on the west side, where the two rivers unite and form the Turanganui. It is only right to mention that Mr Blackett, the Marine Engineer of the Colony, greatly facilitated my inspection at Gisborne, as at the other ports and rivers which I examined when in New Zealand; also that Captain Chrisp, the Harbourmaster at this place, gave me much valuable information as to the local conditions in respect of seas, tides, &c. I have, &c., The Secretary, Marine Department, New Zealand. Jno. Coode.

WAITARA. Sir, — 5, Westminster Chambers, London, S.W., December, 1880. Having duly considered the physical conditions of the tidal compartment of the Waitara, which were observed and noted as far as practicable at the time of my local inspection, and having carefully studied the various features which have been more fully ascertained and recorded in the plan and sections made by Mr. x\. Atkins, in conformity with a memorandum left by me when in the colony, I have now the honor to submit my report on the question of the improvement of the bar and entrance of this river. The volume of the fresh-water discharge of the Waitara, when compared with that of many of the rivers of New Zealand, is, relatively speaking, but limited, the area of watershed being 500 square miles. The mean annual rainfall is, however, somewhat above the average, being recorded by Dr. Hector as 56 inches. The distance from the sea of the head of the tide—in other words, the length of the tidal compartment —is about three miles. The range of ordinary spring tides is 9 feet at the bar, 6 feet 8 inches at the bridge (which is situated one statute mile from the sea, immediately under the south-western extremity of the Manukori pa), and 2 feet at the furthest point to which the observations extend, viz., 1J mile above the bridge. Although the range of ordinary spring

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tides at the lower end of the new wharf, just below the bridge, has been ascertained to be 6 feet 9 inches, the highest tide recorded at the same point was 9 feet. In the notes furnished by Mr Atkins on completion of the special survey, in July, 1879, he mentions that the range of the highest spring tide outside the bar for the previous twelve months had been 12 feet. I find from the Harbourmasters^ daily records for the year 1877, that the greatest depth over the bar at high water of spring tides was 11 feet 6 inches, but this was found only on four days. The records also show that a depth of 11 feet and upwards was found on twenty-four days, and from 10 to 11 feet on seventy-one days, in the same year. The minimum highwater depth recorded during the same period was 6 feet. Depths ranging between 7 and 8 feet were recorded on seventy days, these last named occurring, as might be expected, at the time of neap tides. The yearly average depth on the bar at high water during the six years, 1872 to 1877, both inclusive, appears to have ranged between 8 feet in 1875, and 9 feet 9 inches in 1872. Throughout the whole length of its tidal compartment the Waitara is greatly encumbered by deposits of shingle, brought down from the back country in times of heavy flood. At the entrance, i.e., immediately within the line of high water on the coast, there is, on the right or eastern bank, a considerable spit of sand and shingle intermixed. This spit causes an inconvenient bend in the navigable track of vessels when entering or leaving the river There is also an isolated bank of shingle, about 400 yards long, and averaging about 60 yards wide, situated half a mile below the bridge. This bank has the effect of dividing the river's course into two branches, thereby robbing both the tidal and fresh-water streams of much of their useful scouring effect at this part of the river. When making my inspection, the Harbourmaster (Mr Cameron), called my attention to what he regards as the advantage the entrance of the Waitara derives from the Airedale Reef, "which lies about three-quarters of a mile on the north-east of it, and from another reef of about the same size on the south-west. With the wind from north-east or from south-west, these reefs will doubtless have the effect of mitigating, to some extent, the force of the sea at the immediate entrance, but, having regard to the fact that the heaviest seas always tend to break directly on to the shore, or just to the westward of north (magnetic), I think the value of these reefs is somewhat overrated, and that this will be more clearly seen by reference to Drawing No. 1, which shows the position of the reefs with regard to the entrance. There can be no doubt that, as Mr. Cameron stated to me, the Waitara entrance is one which vessels very easily get away from, or, speaking nautically, is one which has a good " loose "; this is unquestionably a great advantage, as is also the fact, mentioned to me by the Harbourmaster, that the holding ground outside the entrance is unusually good. It appears, from information obtained at the time of my inspection, that there is a growing trade out of the port, even in its present natural or unimproved condition, in respect of cattle and sheep which are rapidly fattened in the rich pasture lauds of the surrounding district ; and it was further stated that this trade, as well as that in agricultural produce generally, would become very considerably increased if the harbour were improved. Works of Improvement. As is usually the case in dealing with harbours of this kind, the works of improvement may here be advantageously classed under two heads, viz. : (a.) Works adapted for the removal or improvement of the bar which impedes the ingress to and egress from the port; and (b.) Works for the amelioraiion both as regards depth of water and alignment of the navigable channel within, together with the provision of berthage and quay accommodation for loading and discharging vessels engaged in the sea-borne traffic. These works I shall now proceed to describe in the order above indicated, merely premising that, after much careful consideration, I have satisfied myself that smaller or less comprehensive works cannot be expected to secure permanently the depths shown in red on the section, which are by no means greater than would be called for if the port is to be made available at all times for steamers of the size properly suitable for, and generally engaged in, the coasting traffic of New Zealand. If, as is probable, the present or immediately prospective trade will not warrant the expenditure for the works hereinafter described under both heads, it may nevertheless be a matter for consideration whether the outlay necessary for executing those under the second head (6.) would not only be reasonable, but fairly demanded by the requirements of the case. External Works. A reference to the drawings, and especially to No. 2, will show that the southern breakwater or training pier would commence at a point on the shore marked A, about one hundred yards westward of the wreck of the s.s. "Patterson," and, running therefrom in a north by west direction, would gradually curve around westward until it pointed N.N W at its seaward termination, marked B, the total length of this arm from A to B being 1,600 feet. The northern external work would commence at the point C, on the north-eastern shore, at about 500 feet from the centre of the channel, and, running therefrom in a N.W by W

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direction for 500 feet, would thence curve to the eastward until, at its outer end, it pointed N.N.W., leaving a distance or clear water-way of 200 feet between it and the southern work ; the total length of the northern arm C. to D. would be 1,50) feet. The width of 200 feet for the entrance has been determined after due consideration of all the conditions of the case. The south breakwater would terminate in 1.2 feet at low water, or 21 feet at high water of spring tides ; whilst, in the case of the northern arm, the depths would be 9 feet and 18 feet respectively, which latter would represent the depths that could be relied upon as available for navigation on completion of the piers to the full extent above described. The channel in the entrance would be subject to some temporary reduction in depth, say, to the extent of 2 feet, after heavy on-shore gales, but the normal depths above-named would be speedily restored on the recurrence of settled weather. It will thus be evident that, subject as the entrance would be to the temporary reduction of depth just explained, training piers of less length would fail to afford such an approach to the Waitara as would be desirable if any material improvement is to be effected. Although the data available here as to the physical features of the river, and the coast immediately adjoining thereto, are amply sufficient for determining the principle on which the external works of improvement should be based, and also for indicating with certainty the proper lines for and extent of these works, the information now at hand does not suffice to enable me to determine with reasonable confidence upon the best mode of construction for these works, or to frame an estimate of their cost. If, however, it should be contemplated to proceed with these outer piers, now or hereafter, I would suggest that the matter should be placed in the hands of the Colonial Marine Engineer, in order that the requisite data may be procured in the locality, and an estimate framed by him, founded upon such mode of construction as he may consider best, having regard to the character and prices of the materials available, and the nature of the bottom along the lines of the two arms. Internal Works. The works for the improvement of the river channel, taken in the order of their importance, are : (1.) The training banks on either side just within the coast line, marked respectively E, F, and G, H, on Drawing No. 2, the former measuring 1,200 feet in length, and the latter 800 feet; the low-water distance, or breadth of channel, being 200 feet. These banks would consist of rubble stone deposited as pierres perdues, and brought up to 3 feet above the level of high water of ordinary spring tides. The spaces between the outer ends of these embankments and the inner ends of the external training breakwaters, if and when the latter were constructed, would form wave-basins, which would be found very advantageous in absorbing any undulations that might enter between the breakwaters. Prior to the commencement of the training bank on the north side, the point of the shingle-spit should be excavated down to the level of low water of spring tides, and the remainder, which the strength of the currents may not suffice to scour, should be removed by a small dredger, if such can be procured, or by some other appliance suitable for the purpose. (2.) Reverting to the isolated shingle-bank, mentioned in the early part of this report as existing about half-a-mile below the bridge, I have to recommend that a small half-tide training bank, 650 feet in length, be constructed on the curved line shown in red on Drawing No. 2, thereby directing the whole force of the outgoing and incoming currents into the main channel, and thus utilizing their scouring effects to the greatest practicable extent at the smallest possible cost. The construction of this training bank will necessitate the protection by fagoting of the south bank of the river, between X. and V on the drawing, being a length of 1,200 feet. As explained in the note on the drawing, the execution of this fagoting should precede that of the training bank. (3.) In order to stop the back-channel, between the island and the north bank of the river, a barrier bank 180 feet in length should be constructed as shown. This work would further aid in concentrating the scour of the currents in the main river course. I estimate the cost of the foregoing internal works as follows, namely : — Two training banks (marked E, F, and G, H, on plan) just within the £ entrance, together with the removal of the shingle-spit to the extent crossed by red lines . 12,250 Curved half-tide training bank, about half-a-mile below the bridge, together with fagoting on south bank, from X to V, also barrierbank from the island to the north bank of the river . 1,510 Total . . £13,760 River Channel. With a view to an increase of the tidal volume, and also to effect an improvement in the navigation to and from the wharves below the bridge, I have laid down on the plan and section, Drawing No. 2, lines indicating the position and depth of the new channel, the formation of which would, I apprehend, require some assistance from dredging. It will be seen that along the south bank, from the bridge to the point X, a distance of 1,200 yards, the line I have adopted corresponds with that previously laid down by Mr Blackett,

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I do not put forward this rectification of the channel below the bridge as a work necessary for immediate execution, seeing that the scouring action of the currents, when aided by the effect to be derived from the training and stop banks, may be fairly expected to bring about a very decided improvement both in the line and depth of the channel course; it could only be determined after the lapse of a reasonable time—say twelve or eighteen months —how far the newly-trained currents would assist, without dredging, in the creation of such a channel as is shown upon the drawing. The training and deepening above-bridge, shown by red colour on plan and section, Drawing No. 2, would still further improve the tidal development and add to the scouring effect, but, like the channel deepening below the bridge, I do not put them forward for immediate execution. I desire, in conclusion, to express my thanks to Mr Halse (the Chairman) and to Colonel Trimble and Mr Webster, members of the Waitara Harbour Board, who accompanied me at the time of my visit to the locality, and rendered me every possible facility in the course of my inspection ; nor must I omit to mention that Mr F A. Carrington, of New Plymouth, accompanied me on my visit to the Waitara, and was good enough to furnish me with a copy of a plan made from a survey of the tidal compartment and entrance of the river, admirably executed by him, in the years 1841-42-43, and showing its condition at that time. I have, &c, The Secretary, Marine Department, New Zealand. Jno. Coods.

WESTPORT, BULLER RIVER. Sir, — 5, Westminster Chambers, London, S.W., December, 1880. I have the honor to submit my report on the works which I have to recommend for the improvement of the entrance of the Buller River, at Westport, in order to remove the bar which now obstructs it, and for the deepening and training of the channel up to and beyond the existing coal-staiths and wharves along the frontage of the town. With this report I beg to forward three drawings, which, with the description and explanation hereinafter given, will fully elucidate my views and recommendations. Drawing No. 1 contains a plan and section of the Buller River, based on a survey by Mr O'Connor, C.E., which was made in accordance with a memorandum framed by me when in the colony • this plan and section show the course of the river, and the levels of the bed, together with the several waterlines between the Nine-mile Ferry and the sea, on a scale of 1,000 feet to the inch. Drawing No. 2 has been prepared in order to show in detail the works referred to ; these works are in each case indicated by red colour Drawing No. 3 gives sections and other particulars indicative of the mode of construction I should recommend for adoption. Physical Features. Watershed and Rainfall. —The Buller River (Kawatiri) takes its rise for the most part in the district lying on the western flanks of the two lofty ranges known as the Spencer and St. Arnaud Mountains (Mount Franklin, situated in the former, being 10,000 feet above the sea), and on the eastern and western flanks of the Victoria Range; there are also a few minor tributaries of the Buller which flow down from the southern slopes of the Merino Mountains. The river enters the sea in a due northerly direction at the Town of Westport, where the coast runs due East and West, and about eight miles to the eastward of Cape Foulwind. Only one of its tributaries is trapped by a lake (Rotoiti), and, therefore, as remarked by Dr. Hector, it is subject to exceptionally heavy floods. The total area of the watershed of the Buller is 2,340 square miles, and the average annual rainfall 95 inches. The floods in this river are occasionally very severe, more especially when, as often happens between October and January, heavy rainfall may occur, simultaneously with such a temperature as to cause the snow to melt in the higher regions. In proof of the extent to which the Buller is affected by floods, I may mention that at the head of the tidal compartment —viz., opposite Waimea Creek, which is about five miles from the sea— ordinary floods will raise the water-surface to the extent of 18 feet above the level of high water of average springtides ; whilst the flood of November, 1877, raised the water in this part of the river no less than 28 feet above high-water springs. Depth on the Bar under existing conditions. —It will be readily understood that floods of such magnitude cause a considerable scour on the bar, but the Harbourmaster, Captain Leech, states in his register that " heavy floods have a tendency to widen and flatten the bar rather than to increase the depth." This remark, although correct under certain conditions of wind and sea, will not hold good on all occasions of heavy river flooding, as very much must depend upon the character of the sea on the coast and bar at the time when the floods may occur. According to exact records kept since October, 1875, it appears that the average depth on the bar at highwater springs, from that date to March of last year, was 14 feet. When at Westport, Captain Leech stated to me that from January, 1873, to July, 1876, the depth at high-water springs averaged about 16 feet, but that about the latter date shoaling commenced, and continued until

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towards the end of 1877, when the water on the bar was again deepened by the exceptionally heavy flood which occurred on 4th and sth November; the improved condition of the entrance holding good until the end of March, 1878. The fact of the maintenance of a depth averaging nearly 16 feet at high water of spring tides for so long a period as three and a half years— namely, from January, 1873, to July, 1876, as above stated —cannot, I think, be regarded as otherwise than most encouraging, seeing that it indicates a much greater approximation to a balance between the forces which tend to heap up the bar, and those which operate to keep it down, than will be found at any other river entrance on the west coast of the South Island. I attribute this favourable state of things mainly to the circumstance previously alluded to, that the direction or trend of the line of coast on which the Buller enters the sea is practically East and West, or, speaking generally, almost at right angles to the line of discharge of the other rivers adverted to. It should be noted that, whilst the embouchures of all the large West Coast rivers are for all practical purposes as much exposed to the southerly and south-westerly as to the northerly and north-westerly seas, the mouth of the Buller is quite sheltered from the southerly and south-westerly quarters of the compass. Such being the case, the power of the sea to cast up the sand, &c, in the form of a bar at the Buller mouth, is much less than at the other western rivers, whilst the fresh-water discharge is much greater. I must not omit to remark that, whilst the conditions as regards the aspect of the entrance, and the volume of fresh water, are exceptionally favourable, the lengths of the sheltering and guiding breakwaters requisite to insure a permanently good depth will necessarily be great. Upon referring to Drawings 1 and 2 it will be seen that the mouth of the river is incumbered by shoals and banks, flanking the bar proper on either side, so that a depth of 12 feet at low water of spring tides is only reached at a distance of about 6,000 feet seaward of the high-water lines of those tides on the East side of the entrance. It follows, therefore, that works of unusual length will be necessary to form an entrance in a sufficient depth for the regular ingress and egress of such vessels as may be expected to visit the port. Works recommended. The works 1 have to recommend for execution with a view to improve the entrance to ne Buller, and also for the rectification of the internal banks and line of channel at the seaward end of the river, are shown b}' red color on Drawings 1 and 2, detail cross-sections of the respective works illustrating the mode of construction to be adopted being given on Drawing No. 3. The proposed works may be divided into two groups—viz : those for the improvement of the entrance, which are of primary importance, and those for the internal rectification of the channel, which latter may be undertaken after the outer works have advanced to a sufficient extent to concentrate and train the tidal and flood waters so as to scour and maintain a channel having a satisfactory navigable depth across the bar. External Works. These works consist of two training breakwaters or moles, one on each side of the entrance. The west breakwater would commence at the point C on Drawing No. 2, and run at the outset in a northerly direction, gradually curving therefrom so that the outer portion shall point N.N W until reaching the proposed termination marked D, the total length from high-water mark of ordinary spring tides to the end being 4,400 feet. The east breakwater would start from the point A, and extend therefrom in a north-westerly direction, curving thereafter towards the East, the outer portion being parallel to the western work, and terminating at the point B, the clear water-way or entrance between the breakwaters being 600 feet. Calculation here has shown that this width of 600 feet will be sufficient for the passing seawards of the flood waters without throttling Should it, however, appear during the execution of the moles, that either a greater or less width of opening is desirable, the lines of the arms have been so laid down that their outer portions may either converge, or be placed further apart, as experience may determine, although it is not probable that any deviation from the width of 600 feet will be required. A N.N W aspect for the entrance has been decided upon, after careful consideration, as being better suited than any other to the circumstances of the case. This direction has been found to afford a longer continuance of deep water on the bar under existing conditions, after the occurrence of freshets, than when the channel has pointed more to the East or to the West; and there are other reasons, associated wiih facility for entering and leaving the port, which indicate that the permanent entrance should bear N.N W The principle upon which the two training moles or breakwaters have been designed corresponds with that upon which I framed the projected works at Greymouth. The object of the breakwaters is to concentrate the efflux and reflux currents, so that they shall be compelled to run over a definite and fixed track of proper proportions, instead of spreading, and consequently losing their scouring effect, on their arrival at the embouchure of the river as they do at present. The west breakwater is shown to overlap that on the east side to the extent of 400 feet. This overlap is necessary in this case in order to provide for the normal travel of the beach in an easterly direction, although the transportation of material from this source at Westport will be small when compared with similar forces which are in operation at many of the New Zealand river entrances.

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It is considered that the training breakwaters above referred to would produce, when fully executed, a depth of 12 feet at low water of spring tides in the entrance, being equal to 15 feet at low-water neap tides, 20 feet 8 inches at high water of those tides, and 23 feet 4 inches at high water of spring tides. In considering the net navigable depth in the entrance of this river, an allowance of 6 feet should be made for " scend," or wave-undulation, during heavy weather, and of 3 feet for clearance under the keel, so that vessels drawing up to 14 feet would be able to enter the Buller during an onshore gale at spring tides; whilst during fine weather the full draught of 23 feet 4 inches at high water of spring tides, and 20 feet 8 inches at high water of neaps, less, say 2 feet for clearance under the keel, would be available for navigation purposes. Having regard to ordinary conditions, it is not desirable to provide for a less ultimate depth iv the entrance than that above stated, and therefore works of less length cannot be relied upon to produce altogether satisfactory results. Moreover, by placing the entrance in this depth it will be less subject to fluctuation from disturbance of the bottom in consequence of wave-action, than if formed in shallower water. Should the requisite funds not be forthcoming for the construction of the two breakwaters in their entirety, which is not improbable, then any works which may be undertaken with a view to increase the depth on the bar ought to be executed, as far as it may be practicable to carry them, upon the lines laid down on the drawings which accompany this report, so that they may be extended hereafter, with a view to the ultimate attainment of the permanent deep-water entrance to the Buller which I have described. Drawing No. 3 shows in full detail the character of the works proposed. It will be seen that they are intended to consist mainly of pierres perdues, the inner portions, where not exposed to the full stroke of the sea, being deposited from " end " and " side-tip " waggons, as rubble embankments, whilst the outer or terminating lengths would be tipped from a suitable timber staging. The stone for both breakwaters would be procured from Fairdown Hill, about seven and half miles from Westport, and conveyed therefrom on a branch railway, about one and a quarter miles in length, connected with the main Government line. The stone at Fairdown is quartzose sandstone, in the form of boulders along the hill-side. The outer portions of each of the breakwaters over the lengths shown on the longitudinal sections, Drawing No. 3, would be coated with concrete blocks of 22 tons each, arranged " pell-mell " so as to protect the rubble from the wash of the sea. In this manner much less stone will be consumed than would be required for a mole entirely of rubble, and a more stable mound will be produced; moreover the judicious combination of concrete with stone will be more economical than if the latter material were alone employed. Along the crest of the west breakwater there would be a rib of concrete-in-mass, deposited within frames in situ, as indicated on Figures 4 and 5, Drawing No. 3, in order to afford an approach to the small cast-iron lighthouse proposed to be erected at the end of that work. The outer end of the eastern breakwater, for a length of 1,000 feet, would be brought up only to half-tide level, with a view to provide for the more ready escape of flood waters ; this length of low level mound might be reduced, if necessary, or be raised upon, should it prove from experience that the relief which it is intended to afford could be diminished or dispensed with. Internal Works. These consist of training banks of rubble stone, with their tops formed at half-tide level, commencing on the west side of the river, at a point opposite to 4,000 feet above Bentham Street, and extending seawards therefrom by lines of easy curvature in the position indicated by striped red color on Drawing No. 2. There would be an opening left in the western bank abreast of the entrance to the " Future Floating Basin " to which reference is made hereafter The bank on this side would terminate at a point about 300 feet seaward of a line drawn from the commencement of the west breakwater, and distant 1,200 feet therefrom, so as to form a wavebasin for the dissipation of " scend " or undulation which might enter between the breakwaters during gales. On the east side the internal works would consist in joining up the existing wharves, and in constructing a half-tide training-bank seaward thereof, and parallel to the bank on the west side, so as to form, in conjunction with the latter, a low-water channel of 500 feet in width. The outer end of the eastern bank would finish at a point 1,200 feet seaward of the commencement of the eastern breakwater, and at a distance of 800 feet from that work, thus forming a wave-basin on the east side for a similar object to that previously described on the west side. There would be a small port light placed on the ends of each of the training banks for facilitating the entry of vessels at night. Formation of Channel. There cannot be a doubt that the execution of the external and internal works previously described will have the effect, by scour alone, of materially improving the depth in the channel opposite the town and seaward thereof. It is more than probable, however, that this scour would have to be supplemented by dredging; in any case it is desirable that the permanent bed of the channel should be formed at the level, and to the gradients, shown on the longitudinal section, Drawing No. 1 In the following estimate I have assumed that one-half the materials now overlying the bed of the proposed channel will be removed by scour, and that the remaining half must be dredged.

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Estimate. I estimate the cost of the foregoing works as follows : — West breakwater, completed to the full length of 4,400 feet, including £ staging and the provision of such railway approaches, with a temporary bridge across the river, as will be required to convey the stone from Fairdown to the works 266,400 East breakwater, with railway approaches, &c, completed to the full length of 6,000 feet . . 172,376 Total for the two breakwaters 438,776 Dredging the new channel to the extent previously described, including up-keep and working expenses of all plant, but not the first cost of the dredger .. 50,000 Total .. .. .. . £488^776 The above sums include a fair allowance for contingencies, and for the provision of plant. They will no doubt appear large for the execution of the works, but I feel confident they cannot be carried out in a permanent and satisfactory manner, having regard to the unfavorable conditions of the site with respect to the distance of deep water from the shore; nor can a thoroughly effective deep-water entrance to the Buller be formed for a less total outlay than that abovenamed, although, as previously explained, a pro raid benefit may be expected to accrue from the partial execution of the two external breakwaters. I have not considered it desirable to estimate the cost of the internal training banks, seeing that these may well be left for future consideration, and may be undertaken hereafter, when the trade of the port shall have grown to such an extent as to warrant the further outlay which would be required for their execution. In framing the design previously described, I have kept in view the necessity for providing plain substantial structures adapted to the circumstances of the case, and such as, in my view, will be required at no distant date for meeting what will prove the growing requirements of this, which may be expected to become, the coal port of New Zealand. The two external breakwaters, for similar lengths to those described, might be constructed in timber for the sum of £162,200 for the west breakwater, and £183,900 for the east breakwater; or together, £346,100, as compared with £438,776, if formed of stone and concrete. I would not, however, recommend this mode of construction, seeing that timber works will inevitably prove a constant source of outlay in up-keep and maintenance; and it is in every sense desirable that the two external works, to whatever extent they may be executed, should, in the first instance, be carried out in a permanent manner. Future Dock. Having regard to the extensive beds of high-class coal in the surrounding district, and the consequent probable large development in the trade of Westport at some future, and possibly not very remote, date, I have thought it desirable to indicate, as I have done by thick dotted red lines on both of the accompanying drawings, the general outlines for a project for a floating basin, to be formed in the lagoon on the western side of the entrance. It will be seen on reference to the drawings that this lagoon would admit the formation of a very extensive basin, in which vessels could lie to ship coals, the railway being carried across the river for this purpose, say at a point between Fonblanque Street and Mill Street, as shown. I regard this scheme as worthy of consideration when the shipping facilities of the port shall require extension, seeing that vessels lying in the river must occasionally be exposed to great risks from the exceptional violence of occasional floods, one of which I witnessed at the time of my visit; and I may remark that, as the number of vessels frequenting the port may increase, the greater will be the risk of damage occurring to them, by reason of the greater obstruction they would offer to the passing waters; and, the greater the number of vessels lying in the river, the greater in all probability would be the amount of damage that would be caused. Moreover, vessels lying in such a basin would be quite free from the great risk of injury to which they would be liable from the trees (many of which are very large) brought down with dangerous velocity at the time of heavy floods. It should be noted that the physical conditions of this site are such that the basin might b& commenced on a comparatively small scale, and extended from time to time according to the requirements of the trade. New Relief Channel. I gather from the longitudinal and transverse sections taken in January of the present year,, and forwarded to me with the other documents, that the making of a new " relief" channel between the upper end of Sluice-box Falls and the lower end of Snag Falls, near Oamaru Creek, which I stated when in New Zealand would be preferable to repairing the old bank, has thus far been attended with satisfactory results. It is not improbable that the bed of the river between the lower end of this relief channel and a point almost a furlong south of gauge No. 13, may eventually require some artificial aid, to reduce the bottom to a closer approximation to an uniform gradient than can be accomplished by natural agency alone. I mention this as a matter 2—H. 19.

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deserving the attention of the colonial engineers, because it should have the effect of lowering the normal level of the upland water at this point, and, in a corresponding degree, would increase the length and consequently the volume of the tidal compartment, whilst it would certainly improve the discharging capacity of the river. If the relief channel should continue to increase in sectional area, it is quite probable that, in course of time, this may become the main channel of the Buller, a result which I regard as very desirable, and which should be encouraged. If the scouring action of the river passing through the relief channel should cause the erosion of the materials on either side to such an extent as to tend to the creation of an unduly wide or tortuous course, it would be well that this tendency should be controlled, by fagoting the sides at such points, and to such extent, as circumstances may indicate to be necessary. Landmarks. The three Steeples rocks, lying immediately to the North of Cape Foulwind, visible, as they are, at fully ten miles from the coast, and the two remarkable white patches in the cliffs to the northward, near Pukukongu Point, serve as admirable marks for approaching the port by day; whilst the revolving light on the cape itself, which is visible from eighteen to twenty miles in the offing, serves equally as a guide to the mariner in making for the port by night; the sea approach to Westport is therefore more than usually well-defined. Conclusion. I desire to record my obligations to Mr. Dobson, the Resident Engineer, and Captain Leech, Harbourmaster, for the local information supplied and facilities afforded me during my inspection of the port and river; to Mr. Blackett, Chief Marine Engineer of the colony, who accompanied me, my thanks for assistance rendered are especially due and hereby recorded. I have, &c, The Secretary Marine Department, New Zealand. Jno. Coodb.

Authority: Gbobgb DIDSBraT, Government Printer, Wellington.—lBBl.

NEW ZEALAND HARBOURS Sketch Copy of Plan referred to in Report

NEW ZEALAND HARBOURS Sketch Copy of Plan referred to in Report

NEW ZEALAND HARBOURS Sketch Copy of Plan referred to in Report WAITARA

WAITARA NEW ZEALAND HARBOURS SKETCH COPY OF PLAN REFERRED TO IN REPORT

NEW ZEALAND HARBOURS Sketch Copy of Plan referred to in Report West port

NEW ZEALAND HARBOURS Sketch Copy of Plan referred to in Report