From Captain Barney, Royal Engineers, on the subject of the projected Quay at the Head of Sydney Cove. Sydney, July 16th, 1836,
Sir, — I have the honor to return herewith, the Documents which accompanied your letter of the 29th ultimo relative to the proposed Quay at the Head of the Sydney Cove.
In obedience to the order of His Excellency the Governor, I have given the subject attentive consi- deration. I have also examined the Cove and Tank Stream, and submit the following observations :— Admitting the construction of the Quay to be a measure of high importance to the prosperity of
Sydney, in every possible point of view, I will pro- ceed to consider the plan of the work : — I see no objection to the line of Quay proposed by the Committee, but it may prove advisable to take advantage of natural foundations, which may effect some unimportant alteration. It is, however, unne- cessary, to enter further on this subject at present. From the evidence before the Committee, it would seem that the great difficulty to be overcome is the Tank Stream, as the immediate agent of the deposit at the Head of the Cove. I have directed my attention more immediately to this point, and am led to consider that undue impor- tance is attached to the effect of the stream. There is, no doubt, a considerable body of matter occasion- ally brought down and deposited between high and low water-mark; indeed, under existing circum- stances, the bed of the stream is in effect the main sewer of a large portion of the town, and from local position, it becomes the channel of conveyance of hundreds of tons of sand, annually, from the nume- rous and extensive streets inclining towards it, in addition to a contribution of every species of filth, from the rear of the premises abutting upon it; but,
in reference to the simple effect of the stream itself, as connected with the deposit in the Cove, I am de- cidedly of opinion, that it is only a very partial and unimportant assistant. The deposit evidently has arisen, and continues to be fed by the soft material with which the streets are supplied, the whole, finding its way into the Cove. This, however, will effect its own remedy as the im- provement of the town progresses, and the sandy beds of the streets substituted by a more durable material, with a necessary arrangement of drainage and sewers. In this view I would propose converting the bed of the Tank Stream into a permanent common sewer, directing its course immediately to the centre of the projected Quay. This sewer, being covered, will greatly reduce the quantity of soil conveyed into it; its present unsightly appearance will be removed; the unwholesome effluvia now arising will be obviated; the improvement of the streets may be carried over it, and the spring or source of the stream, may still be preserved for public use; all tending to the im- provement of the town, and to the increase of the value of property. A portion of soil will still be deposited in the Cove by the sewer, which will probably require to be lifted once in four or five years, by means. of a dredging machine, at a trifling expense of labour. Under any circumstances, dredging must be resorted to in the Cove, which, being devoid of current, must always be subject to formations of more or less magnitude. I would here observe, that a much greater evil than the deposit at the head of the Cove, is to be found a similar deposit on its western shore, extending from Mr. Campbell's Wharf, in front of the Dock-yard, and King's Wharf; and which I also, attribute to the ample supply of material afforded by the streets. There being no current, this matter immediately sub- sides on being forced into the Cove. I think this argument fairly borne out by the ob- servation, that the Eastern shore of the Cove does not exhibit any considerable decrease of water (cor- responding with the Western shore), not possessing the never-failing supply, from the streets. The only remedy for this evil is by the means before stated, viz. the use of proper material for the streets, and an improved system of drainage. Under every view of the Committee, I consider the simple arrangement herein submitted offers the most favourable result, combined with economy of expen- diture. I am not prepared with any estimate of the expense required in the completion of the work; indeed, without the assistance of a diving bell, it is totally impossible to ascertain the extent of foundation re- quired, or the best line of formation of the Quay. Under these circumstances, should His Excel- lency entertain this or any other proposition for pro- ceeding with the work, the assistance of two diving bells will be necessary, which, however, cannot be obtained in this country. A dredging machine is also essential to the clearing of the Cove; the most effective, and eventually the least expensive, will be a dredger to be worked by steam, which will not only be applicable to the Cove, but of the utmost utility in relieving the various river courses of impediments which now operate so un- favourably to their navigation. Both bells and dredgers must be supplied from England, and should be complete to work at a depth of twenty-five feet. The framing required for the former, as well as the vessel for the latter, may be prepared in the Colony. In absence of any correct data to work upon in the formation of a general estimate, it may perhaps seem advisable to appropriate £5000 for the Sewer and Quay, and £2000 for the required machinery, should His Excellency deem it expedient to commence the work without delay. I have the honour to be, Sir, Your most obedient humble Servant, GEORGE BARNEY.