The CORONER: It was not drained.
Mr. JACKSON: That is not in evidence. I have not the least doubt the proximate cause of the bursting of the reservoir was the drawing of the joints of one or more of the pipes, a leakage along the side of the pipes, or both causes together. It is possible there might have been a leakage through a fissure inside coming out under the outside slope of the embankment.
In reply to the Jury: I cannot say whether the joints were drawn or merely sprung. If the valves had been inside of the dam there would have been no tendency in the valves to draw the joints. Moreover, if a joint were drawn, and the water got to the puddle, the embankment would be torn away before any means of preventing it could be adopted, even if the valves were inside the dam.
By the CORONER: It is possible for a leakage from the fissures of the rocks to have re appeared directly under the seat of the outside slope. That would be of itself a cause sufficient to burst the bank unless the water had free vent. That free vent can be obtained in one or two ways. By having the seat of the embankment under the outside slope efficiently drained by cutting trenches and filling them with large stones, that would admit a free passage for the water. Another plan would be to collect all the water in a longitudinal drain at the bottom of the puddle trench, carried all the length of the puddle trench if necessary to the lowest point, and then transversely and up to the surface of the ground, or to the bottom of a drain under the seat of the outside slope. That is a perfectly safe way of getting rid of water, provided the bottom of the puddle trench be all rock. After the evidence of Mr. Gunson yesterday, I do not think anything of this kind necessary.
The CORONER: Then all this evidence is unnecessary.
By the JURY: It is possible for water to have got under the outside slope, without being observed; the ground might absorb it. I cannot tell whether the ground under the embankment at Bradfield would do so without seeing it.
By MR. RAWLINSON: If the outlet pipes have been depressed by settlement of the embankment, it is possible that the puddle may not have followed it. There may thus have been an open space left between the top of the pipe and the puddle.
By the JURY: Could a vertical pressure press down the pipe and not the puddle ?
Mr. RAWLINSON: The pressure would not be equal. The pressure on the two sides may have depressed the pipe faster than the puddle from the side pressure being more rapid then the centre pressure; and the water is there to avail itself of the least opening; and if water thus got in, the consequences would be what we have seen. I have no desire to say a harsh word against those who made this dam, but the embankment has been destroyed; there must be a cause for its destruction, and it is our business to find out that cause if we can.
The CORONER: And the cause is a fault of some sort.
Mr. RAWLINSON: I do not go so far as that.
Mr. PAWSON (foreman of the July) said he concurred in the view of the desirableness of finding out the cause of the accident, and expressed his regret that the engineers of the Water Company, who necessarily knew most about it, had manifested so much reserve.
By the JURY: It might have been advantageous to have had a better and more rapid discharge of water than the two 18 inch pipes when danger was apprehended. I could have devised such a means. A tunnel might have been driven through the solid, round the end of the embankment, That, in my opinion, is by far the best way, and in any work I may have to do again I should lay pipes in a tunnel through the solid, and not under the embankment. Another mode is this -- the stream supplying the reservoir might have been brought round to the by wash by a channel, along the side of the reservoir, 60 as to have given complete control over the flood water. The pressure upon the bank could then have been eased by the outlet pipes.
Mr. GUNSON, re called, said the water was carried along an artificial course during the whole time of the construction of the dam.
Mr. JACKSON resumed, in reply to the Jury: I have constructed larger reservoirs than this in Australia, but none so deep, and it is depth that involves danger. Another suggestion for the safety of the dam is to construct the by wash at a lower level than it is intended ultimately that the water should stand. This plan was suggested to me last night by Colonel Ford, and is valuable, as the water might thereby be regulated by lifts according to circumstances until the bank is thoroughly consolidated. It would be a great protection to a new bank. The by wash might be ultimately raised to the height, required by erecting sluices along the top of it.
By the JURY: If my reservoir at Melbourne had not had valves inside, it would have burst like this. It is better to have them inside because then, if a leakage occurs in the pipe, the water can be shut off. I am of opinion that the accident has not occurred from the rising of water under the outer slope of the embankment, because Mr. Gunson's evidence shows that the rock to which the puddle trench was sunk was impervious.
By Mr. B. SMITH: The works I constructed at Melbourne were 3000 acres, the contents were 38,000,000 of cubic yards, and the depth 25 feet. I have been an engineer since 1846. The wagons on the bank are not what are ordinarily understood as railway wagons; they are much smaller. They are, however, wagons running on rails. Leslie advises six inch layers, and I two feet layers. Engineers, like lawyers, disagree. I have carried pipes under embankments. That has been the universal practice until now. There has been no great disaster from it until now. It has been an error of judgement committed by the most eminent engineers. I should not, after what has occurred here, again lay pipes under or through the embankment. I should take the water through the solid, round the end of the embankment, by culverts or otherwise. I laid my pipes at Melbourne on stone, not puddle, like Mr. Gunson. The two plans have their advantages and disadvantages. Neither of them are good jobs. I collared my pipes and bestowed great pains upon them. My plan was therefore not the right one, but I saved the embankment by having valves inside the reservoir. The pipes would be more liable to fracture on the stones than on puddle. The shields might cut the puddle, and prevent its adhesion to the pipe. I still think they are the best, but another engineer might think differently. After my experience at Melbourne and here, it seems to me foolish to think of placing pipes under an embankment again.
Mr. B. SMITH suggested that the question for the jury was not so much what was to be done in future, but whether the servants of the Water Company had used reasonable care and skill in the construction of the reservoir.
The CORONER: No. That your men have used reasonable care and skill there is no doubt; but we want to get at the real cause of the accident.
Mr. B. SMITH: This inquiry has to do with criminal responsibility only.
The CORONER: Strictly, that is so; but I repeat, we want to find out the cause of the accident.
Mr. B. SMITH: Mr Rawlinson is here to pursue that inquiry. He will find that out, no doubt, and his report to the government will be published.
Mr. PRIDEAUX suggested that if the outlet pipes were bared, the jury would get at the information at once.
Mr. JACKSON: If that is done, you will find it as I say, I have no doubt. What we want to know is, whether there is a leak outside the puddle, because that would settle it.
The CORONER: We can shorten this inquiry if the Water Works Company will be at the expense of baring their pipes, as we could arrive at a result at once. I, of course, have no means of paying for it.
Mr. B. SMITH: I cannot pledge the Water Company to anything without consideration. They want, for their own satisfaction as well as for that of the public, to ascertain the cause of the accident, and will take such means as are in their power to do so. At present, however, we are fighting in the dark, and I must again submit that the question for the jury is simply whether anybody is criminally responsible.
The CORONER: If you wish us to do so, we can soon find Mr. Leather guilty of manslaughter, and send the matter for further investigation at York.
Mr. SMITH: That is a matter for the jury.
The CORONER: The jury have made up their minds not to find anybody guilty of manslaughter. The cause of the accident is too remote to involve such criminality.
Mr. SMITH: We can carry on an inquiry from day to day if you think that is the best course; but I very much doubt whether the Coroner's Court is the best medium for such an inquiry.
Mr. BLAND (a Juror): Is there no means of ascertaining what we want to know without baring the pipes ?
Mr. JACKSON: A few at the end might be bared, and if they have started you might safely come to the conclusion that others have started too.
Mr. RAWLINSON: YOU might bare the outer end, plug up the pipes; then bare the inner end, plug up the pipes and use hydraulic pressure.
Mr. JACKSON: That would answer the same purpose.
Mr. BEARDMORE: But there was such a violent disturbance of the embankment when the bursting took place; the whole ground was shaken, and that may have done mischief to the pipes. If, therefore, you find that mischief has been done to the outlet pipes you won't know when it was done, or when the embankment gave way whether it was done before. That is the real difficulty.
Mr. SMITH: Mr. Beardmore has anticipated what I was about to say. The bursting of the reservoir created a violent commotion of the ground, which may have broken the pipes, however perfect they were before. The fact of the pipes being broken or drawn now, is no proof that the accident arose from that.
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