Mud and other deposits had accumulated to such an extent in the Floating Harbour, that at the end of the year 1832 the directors of the Dock Company employed Mr. Brunel to suggest remedial measures.
In order to effect his object at the least possible cost, he proposed certain works, together with an improved system of managing the water of the river, so as to allow more of it to pass through the Floating Harbour, by means of which great benefit might fairly be anticipated.[178] He remarked that,—
By systematically following this course, the object of which is simply to keep in continual action all the means, however small, which can at the moment be brought to bear, and thus day by day to remove or neutralise, or merely diminish (as the case may be), the continual deposit which is going on—in fact, by applying a constantly acting remedy to oppose a constantly acting evil—I have little doubt that the formation of shoals similar to the existing ones may be entirely prevented, or at all events that they will be of such a nature as to be easily removed by two or three yearly scourings, and without that time and labour which are now expended with so little effect.
It should be observed that the yearly scourings, which became so objectionable to the trade, were not introduced by Mr. Brunel, but were part of the original arrangements of the docks.
After the reception of Mr. Brunel’s report, the Dock Company executed the works which he required, namely, the Sluice, Trunk, and Drag-Boat; but his other recommendations, as to scouring and increased supply of water, were only acted upon to a limited extent.
In 1842 the Directors again asked Mr. Brunel to report, in conjunction with Captain Claxton, upon ‘what further measures are requisite for keeping the Floating Harbour more clear of mud than it has been for a few years.’
Mr. Brunel thereupon made a report to the Directors. After having referred to his previous reports of 1833 and 1834, he remarked that ‘the efficiency of the whole system then recommended and adopted, and subsequently partially carried out, depended entirely and was founded on the supposition of the then existing mud-banks and shoals being first removed, and the Float deepened at once to the full extent required,’ according to the plans which he had pointed out; and that ‘the increasing the supply of water through the Float was one of those means on which he had most insisted’ as necessary for keeping it clean and preventing its becoming a settling reservoir. He then continued,—
The sluice at Prince’s Street Bridge, the trunk—or syphon, as it was originally, and perhaps more correctly, called—at the underfalls, and the drag-boat have alone been brought into operation. These were originally intended as mere aids, which, in conjunction with the increased supply of water, were expected, after the complete deepening of the Float, to be sufficient, with two or three yearly scourings, to keep it to the required depth: these were (perhaps unfortunately) found so effective as to induce a hope that they might be depended upon solely for the removal of the evil. The permanent interests of the port were, I cannot but think, sacrificed to temporary convenience: the scourings which were required as a preliminary step to restore the Float to its original state, or to that which was said to have been its former state, and which is now required, were indefinitely postponed.
A material improvement being notwithstanding soon perceptible from the first effects of the drag-boat and the removal of mud through the trunk, the periodical scourings which formed part of the system approved of for adoption were in a great measure given up to the objections of the traders. The precautions actually necessary against admitting into the Float the tide water of the Avon, heavily charged with mud, were gradually sacrificed for the same reasons. From all these and many other, but very similar, circumstances no further progress has been made since the first improvement, which was felt to be, and which unquestionably was at the time, very considerable. For until this period it had been the general practice to lighten all deeply laden vessels at the entrance of the Float; and, notwithstanding this precaution, it must be in the recollection of everybody that it was a common sight to see several large vessels aground at various shoals in the Float, and unable, without further discharging the cargoes, and without great consumption of time, labour, and ropes, to get up to the quays. For several years past the grounding of the deepest vessels has been the exception, not the rule, but during all this period it has been one continued and almost vain attempt to struggle against the old difficulties with insufficient means.
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