The Severn Tunnel/Chapter 9

by Thomas Andrew Walker

CHAPTER IX.

A WEEK OF TROUBLES.

Progress of the work—1883On the 10th October, 1883, all the work was going on favourably. Everyone connected with it was in high spirits, thinking of rapid completion; and at six o’clock on the evening of that day, when the miners, who had worked the day-shift, fired their round of holes, no extra difficulties and no impending trouble were foreseen.

I had left the works just after six o’clock, after speaking to the foreman of the miners about the number of holes fired in the westward heading at Sudbrook just as I was leaving the office; but I had not been at home more than an hour, when the same foreman drove up to my house to report to me that the Great Spring had broken into the tunnel in larger volume than we had ever yet met with, and that it was rapidly gaining upon the pumps.

I went down with him at once to the works, and on descending the shaft found a river 16 feet or 17 feet wide of bright clear water, flowing along the invert of the tunnel, and leaping down the old shaft Progress of the work—1883. into the lower workings. As it had a drop there of more than 40 feet, the roar of the water, when you were in the tunnel, was deafening. My first action on reaching the bottom of the shaft was to taste the water. To my great relief I found that it was fresh, and we, therefore, had no reason to suppose that we should not be able to contend with this difficulty, as we had with so many before.

It was evident, however, that the water was coming in at a rate very much exceeding our power to pump it out, and therefore the time that would elapse before it rose through the lower workings must be spent in precautionary measures. It was impossible to approach the head-wall in the lower heading, and the door there was open ; but men went up to see that the door in the upper heading was properly closed, and to put additional timbers in the sloping heading to secure the head-wall there.

As there was a hole existing from the tunnel at Sudbrook to the new pumping-shaft on the south side of the line, bricklayers were at once started to close this hole with brickwork in cement. As soon as these works were started, I ascertained the following facts with regard to the inburst of the water.

The night-gang, working in the bottom heading westwards, had gone to work shortly after six o’clock, taking up skips with them, and had begun to shovel up the loose rock dislodged by the blasting, when the ganger said:

‘There is more water here than usual—the Progress of the work—1883.

“Grip” ’ (a small ditch at the side of the heading) ‘must be blocked. Push back a skip or two to clear it out.’

The men had hardly done so, when, to use the words of the ganger, ‘the water broke in from the bottom of the face of the heading, rolling up all at once like a great horse,’ It swept the men and the iron skips like so many chips out through the door and into the finished tunnel; and it was only when the water spread itself over the whole width of the tunnel that they were able to gather themselves up, and save themselves from being precipitated down the old shaft into the lower works. They were swept through the door without the power to check their passage, but they at once endeavoured to work their way back again up the heading, holding one another and clinging to the timbers at the side, to shut the door, if it were in any way possible. All their efforts failed, for the water was running down the heading in a stream 10 feet wide and 3 feet 6 inches deep, and with such rapidity and force that no man could stand against it.

Anxiously we watched the rising of the water. We found that it was rapidly gaining upon the pumps; that it was already 10 or 12 feet deep in the tunnel under the shoots; that the men had all escaped; but that the horsekeeper had, in his terror, ridden off on one of the cobs, and left three others to drown.

Finding, on my arrival at the shaft, that the Progress of the work—1883. pumps were running twelve strokes per minute, I ordered them slowed down to ten. I was particularly anxious that there should be no panic.

A messenger was sent over by the last ferry-boat, to order the men on the Gloucestershire side of the river to at once commence to build a head-wall of brick in cement across the finished tunnel, west of the Sea-Wall Shaft. The men worked all the night and the next day, and completed the head-wall, leaving only a door 3 feet square at the top; but the water never rose so high as to reach the bottom of this head-wall. On the morning of the 11th the water had risen against the pumps to the height of 52 feet. On the 12th, the pumps, still working steadily, held the water at 132 feet from the surface.

A council of war was held, and it being the opinion of all that the inburst of the water might be from a subterranean reservoir, which would shortly exhaust itself, and that we should only have the same quantity of water ultimately to pump that we had before the inburst occurred, it was decided to continue the pumping for two or three weeks longer. After holding it a depth of 132 feet from the surface for two days, the pumps began to gain slowly. By the 22nd they had gained 9 feet 9 inches, and by the 26th, 13 feet.

The cubical contents of the tunnel and other works filled by the water, while the pumps were continually pumping at the rate of 11,000 gallons per minute, was accurately measured; and we found

The Temporary Engine Houses, Sudbrook.

The Permanent Engine Houses, Sudbrook.

Progress of the work—1883.

that the water must have run in at least at the rate of 27,000 gallons per minute, or 16,000 gallons more than we had pumping-power to lift.

Having thus obtained a fairly accurate measurement of the quantity of water we had to contend with, I again engaged the services of Lambert, the diver who had on a previous occasion closed the door in the long heading, as well as the use of one of Fleuss’s diving dresses, in which he had previously done the work. On the 29th he tried to reach the door in the Fleuss dress, but found it impossible to do so.

I think at the time his health was bad, as he had just returned from Australia, where he had been engaged in raising a vessel, the Austral, in Sydney harbour.

On the 30th, however, assisted by two other divers, he went up again, dressed in his ordinary dress, and this time succeeded in closing the door.

By the 3rd November the pumps had again entirely cleared the tunnel of water, and the Great Spring was imprisoned, as it had been in January, 1881.

On the 12th October, just when the water of the Great Spring had gained its highest level and wholly drowned the works at Sudbrook and under the river, the largest of the pumps at 5 miles 4 chains broke, and in a few hours that pit also was drowned, and the works full of water.

At 7 p.m. on the 17th October, the night-shift, Progress of the work—1883. consisting of about 90 men, had descended the Marsh Pit, to proceed with their work.

About 450 yards of tunnel were completed at the bottom of this pit, and two break-ups were being worked, and were in various stages of progress west of it.

It will be remembered that the gradient of the tunnel at this point rose 1 in 90 to the west.

A perfect storm of wind was blowing at the time from the south-west, and it was known that one of the highest tides of the year would occur that night, but no tide had ever been known to come so high as the works at this shaft.

Between the shaft and the river itself, in a south-westerly direction, were a number of small cottages, built by the men employed upon the works, of stone and timber; and there were also several brick cottages, owned by the firm who carried on the Tinplate Works, and inhabited by their men.

Suddenly, in the darkness, a great tidal-wave burst over the whole of the low-lying ground between the shaft and the river. It must have come on as a solid wall of water, 5 or 6 feet high. It entered all the houses, most of which were only of one storey, and rose above the beds on which the children were asleep. The children were saved by being placed upon high tables, or even on shelves.

The bedding, blankets, and many articles of furniture, were entirely destroyed. Fortunately the houses were not thrown down.

Tidal wave, men in boat sawing the timber.

Progress of the work—1883.

The tidal-wave passing beyond the houses reached first the boilers that worked the winding and pumping-engines at the shaft, extinguishing the fires, and then flowed down the pit with a fall of 100 feet. There was a ladder-way from the top to the bottom of the shaft, and by it, when the first force of the water had passed, one or two men who were in the bottom, managed to make their escape; one unfortunate man, after climbing the ladder for about half the height, was thrown back by the force of the water and killed.

Eighty-three men were imprisoned in the tunnel at the bottom of the shaft. As the water rose, they retreated before it up the gradient.

In the darkness, and with the whole of the shaft surrounded by water, it was extremely difficult for the two or three who were on the top to communicate with the works at Sudbrook; but at last one man made his way through the water and gave the alarm. The principal foreman of the works, with his brother and one or two of the assistant engineers and other employés, reached the shaft, not without difficulty—some following the line of the tramway, wading through more than 3 feet of water; some passing over the Great Western line, the rails of which were, opposite the shaft, at least 6 inches under water, and then wading through a shorter distance to the shaft. On reaching the pit-head, where by this time the tide was of course lower than it had been at the first rush of the wave, everything that could be Progress of the work—1883. gathered, water-proof clothing, sacks, timber, and such-like things, were used to try to form a dam round the top of the shaft to stop back the water.

In spite of all that could be done, the water rose in the tunnel at the bottom of the shaft, to within 8 feet of the crown of the arch. Then the tide going back, and the dam at the top being more effectually made, preparations were made to rescue the men who were imprisoned below. The whole of the bottom of the tunnel and heading was under water, and the men had retreated to a stage in one of the break-ups, where they sat not knowing what their fate would be.

The men who had by this time gathered round the top of the pit were sent for a small boat, which was lowered down the pit, and launched on the water in the tunnel, a few men with lights getting into the boat pushed up the tunnel to rescue their comrades; but after going a short distance they came to timbers placed across the tunnel from side to side, which blocked their progress. Returning to the shaft they obtained a cross-cut saw, and commenced to cut away the timbers. They had been at work but a short time, when the saw dropped overboard, and they had to wait until another was procured; but at last the men were all rescued, and brought safely to bank on the morning of the 18th.

The tidal wave had not only drowned the Marsh Pit, but had come up with sufficient force to flow

Cutting, flooded after the high tide October 17th 1883.

Progress of the work—1883.

in considerable quantity over the sea-wall on the Gloucestershire side of the river, and the meadows around the shaft were, on the morning of the 18th, covered with water, which stood 8 inches over the rails of the tramway.

To the westward of the Marsh Pit the same tidal wave had flooded the whole of the meadows, and the sea bank round the cutting at the western end of the tunnel not being completed, the cutting was full of water. Fortunately, the heading from this cutting to the tunnel had not at that time been completed, or the works at the Hill Pit would also have been drowned by the action of this tidal wave.

On the morning of the 18th the works of the tunnel were in a worse position than they had been since January, 1881; and though each difficulty had been successfully contended with as it arose, it was yet to be ascertained whether we could hope, without great delay, to arrange sufficient pumping machinery to cope with the body of water which it was evident we had met with between Sudbrook and 5 miles 4 chains.

The pits at 5 miles 4 chains and the Marsh were soon clear of water, and work was resumed at the Marsh Pit on the 23rd, and at 5 miles 4 chains on the 19th. As soon as the pumps cleared the tunnel under the river of water, on the 3rd November, the work upon the Gloucestershire side of the river was resumed with the full force of men; but as an Progress of the work—1883. additional precaution against the Great Spring, for fear of the rising heading (which had not been thoroughly secured, and was in bad ground) giving way, a large head-wall of brick in cement was built across the full-sized tunnel, 260 feet west of the Sudbrook Pit; at the same time a concrete wall was built round the boilers, engines, and pit at the Marsh, so that even if we were visited by another wave of corresponding height, we should at least save that pit from being drowned, and the fires in the boilers from being extinguished.

The height of the tidal wave was found to be 10 feet above the calculated height for the tide on that night.

Large quantities of timber, which had been stacked at the Marsh Pit, were floated away to some distance, and one large larch-tree, 15 inches in diameter, was landed upon the top of the post-and-rail fence east of the Marsh Pit; the fence being 4 feet 6 inches above the level of the meadows.