The Sun.
London, England, 1864-03-24 00:00:00

was quarried the same as ours, and that subsequently a
large quantity of water found its way below the stratifica-
tion of the puddle bank, and leaked out a considerable dis-
tance below the embankment. I am not aware that any

special arrangements were made t 3 prevent the water creep-
ing alongside the two outlet pipes by putting collars around
them, lam not aware that one of the Birmingham reser-

voirs six or seven years ago was destroyed by the water
creeping along the cast• iron pipe and blowing a hole through
the embankment like a tunnel. I should think in any such

ease it would be detected by a previous leakage. lam not
aware that a considerable body of water was issuing under
the side wall below the embankment before the bursting of
the embankment. Ido not know how long a pipe such as

the outlet pipes would last. Everything will come to de-
struction sooner or later. Ido not know how far the two
pipes were placed apart,
John Gunson—l am the acting engineer for the Sheffield
Water Works Company, and have bad the construction of
the Bradford Reservoir from the plans of Mr. Leather. The
embankment was made in the usual way, but it was found
necessary to dig the puddle trench deeper than we origin-
ally intended, the reason being that there was so much
water. We went to a depth of 60 feet. There was a very
large flow of water, which was pumped out by two engines,
one of them working a 12-inch pipe and a 13-inch pipe.
The other pumped two 12-inch pipes. Together they would
be about 20-horse power, and they were kept constantly
working for nearly two years. This shoves that a large body
of water came through the rocks to the puddle. We gotlrid
of the water by pumping it out. The water originally came
out of the reservoir, about 100 yards north TA' the embank-
ment. It was caused by a fault or throw of the rock,
and came away from the tops of the hills, perhaps miles
away. When we got the puddle trench In, that was
an effectual barrier, and the water from that spring
was thrown back into the reservoir. The puddle trench
was cut and worked in the ordinary way. When we got
above the level of the spring the consequence was of course
that the water had to make its way back again. The trench
laid for the pipes was 9ft. or 10ft. wide, and perhaps the
depth was equal to the width, but ran up considerably
less. The pipes were laid in puddle, at a distance from
each other of 2ft. 6in. The depth of the puddle
above and beiow the pipes was 18in. It was the same
kind of puddle as the puddle-wall—the best. The trench
was filled up with the best material, thin layers of
gravel, and very solid. We put in the materials of the
embankment in layers or tips. There were- bartows used,
three-wheeled carts, two-wheeled carts, and waggons. We
did not take the material for the embankment indiscri-

minately from the banks of the reservoir, and tip it on toe
embankment. First, 24,000 cubic yards entirely of stone
was placed on the outward slope of the bank, the stone form-
ing an embankment itself up to within 50ft of the top of the
embankment. The object was to prevent the embankment
slipping on the surface it was placed on ; and to get that.
done effectually we paid 3d per yard additional for the work.
The next process was so to lay the material that the finer
sort came up to the puddle wall. The work was somewhat
similar to that which is going on at present at the Agden
reservoir. The material is also generally the same—fit, I
consider, for the work which it had to do. [Plans showing
the course of the pipes were here produced, and handed for
the inspection of the jury.] Great precautions were taken in
laying the pipes in the puddle french. The puddle trench was
40ft or 50ft below where the pipes went. The pipe trench was
about 9ft below the surface. About a couple of lengths of
pipe went through the puddle trench proper. My fear was
if nothing was provided, the puddle in the puddle trench
being deeper than in the pipe trench, it might sink; and so
we made a special arrangement for the protection of the
pipes, by an extension of the width of the puddle wall. This
was done to the extent of something like 100 ft on either
side. The pipes being socket pipes, they would admit of
some small degree of inflection without breaking. The pipes
were inserted about six inches into each other, lead being
used for from three to four inches. The pipes were laid
in good strong shale, not compressible by pressure. No
water could possibly creep along the pipes. The sockets
of the pipes were cast a little large back than they were in
the front, so that the internal pressure of the water should
not force the lead out, To do so it would have had to act
as against a wedge. There were no collars put upon the
pipes to prevent the water creeping along—the sockets of
the pipes themselves formed collars, and they were very
strong ones. The lines of pipes were 2ft Gin apart. The
sockets were so large that had they been placed opposite it
would have reduced the puddle to that extent—so I ad-
vanced one line of pipes a yard above the other.
The Court at this stage of the inquiry adjourned for half
an hour.
Mr. Gunson recalled and examined by the Coroner—The
Parliamentary plans are not here, only the working ones.
The former can be given to Mr. Rawlinson. The plans car-
ried out were not precisely the same as the Parliamentary
plans. We discovered that the ground where we first in-
tended to put the embankment was faulty; there had been
what we call a landslip. I should say that landslip was
some hundred years old. I did not observe it first: After
I discovered it would not be safe I saw Mr. Leather, and
he gave directions that it should be made where it is.
We had not begun the work at the first embankment,
but the contracts were let. The rainfall of that
district from 1859 was as follows :-1859, 46'055 inches ;
1860, 44'280 ; 1861, 37'940 ; 1562, 401060 ; 1863, 40100.
The smallest flow of water in the summer is halt a cubic
foot per second for each thousand acres of the watershed,
and the maximum 150 cubic feet per second per thousand
acres. The gauge was placed in the Rivelin valley before
we went to Parliament, and when we got the Act I had it
reconstructed. It was 18ft wide. The heaviest flood we
have had occurred in August, 1856. The overflow was 60
inches, and it took away the gauge. The gauge was kept
at Bedenires, about 1,200 ft above the level of the sea. On
the south side of the dam we have en artificial cutting. That
was to divert the stream during the construction of the re-
servoir, and we used till about a year ago. The embank-
ment was finished before then, with the exception of where
the weiring is at the south end, which is not finished yet.
Some of the materials got out of the cutting might be brought
into the embankment, others washed away. In Aug.t 1856,
we had 9 in. of rain—the highest quantity in any month. It
would take 14 or 15 inches to fill the reservoir, so no flood
could materially affect it. When we bared the rock we had
no apprehension that mischief could arise; and I was per-
fectly satisfied that no water coming from the rocks could in-
jure the embankment, because we sunk the puddle trench far
down into the rock below any excavations ia the reservoir.
It was put down into measures quite impervious to water.
The water seen coming out of the rocks where the reservoir
has been flows into the river. It is possible it might drain
into the embankment, but it would be stopped by our puddle.
It was not at all a hazardous proceeding to bare those rocks.
We might have got material elsewhere to make the em-
bankment if we had bought 100 acres of land for the pur-
pose. There are about 400,000 cubic yards in the embank-
ment. We should not have required, 100 acres if the ma-
terial was anything like. I cannot say how many acres of
the rock we have bared ; eight or ten, I should guess. We
•did not find all the material for the embankment in the
baring of the rock.
By Mr. Rawlinson—l intended to make an opening 60ft.
long in the by-wash, There was a drop in the by-wash
which would have let all the water of that breadth to go off.
We were not able to make the breach in the by-wash. I
heard the shot go off atter the embankment had burst. The
water lowered rapidly in the meantime, though I did not see
how much.
Mr. Gunson explained that he never apprehended danger
until he saw the water dashing over the embankment, and
that he thereupon sent persons to warn the nearest resi-
dents. He had no time to warn anybody lower down.
Before the jury separated, .Mr. Rawlinson, Government
Inspector, said some calculations had been prepared with
regard to the flood. The total fall from the dam-head to
0 wlerton was 4501 t,, or 72ft. per mile. The velocity between
those points of the flood was 18 miles per hour, showing
that the water passed at the rate of 261tt, per second. The
average area of the cross sections of the flood between the
same points was 3,780 feet, showing that 40,170 cubic feet
of water passed per second. At this rate the reservoir would
empty itself in 47 minutes ; the weight of water was
3,250,000 tons. After the dam broke, a Derby horse could
not have carried the warning down the valley in time to be
of service.
The inquest was than adjourned until Thursday.