ON THE INDUSTRIAL USES OF THE UPPER BANN RIVER. 141 
to the depth of water in the reservoir, to give the regular supply allowed to 
the mills. The greatest depth to which the reservoir is filled over the level 
of discharge of these pipes is 384 feet; when this is the case the surface of 
the lake is about 250 acres in extent. It was intended to have been 40 feet, 
but the works were not carried out to that extent. The culvert, as Mr. 
Bateman tells us in his paper, has given some trouble, since the superin- 
tendent did not carry out the work in accordance with his designs, having 
surrounded the arch with rubble-backing. The cement, which was made on 
the ground from the specification of M. Vicat, just then published, gave way 
under the water pressure, was washed out of the joints and allowed the 
water to escape from the reservoir through the rubble-backing. Mr. Bateman 
then had part of the backing removed and replaced by puddle, and the inner 
joints of the tunnel caulked with oakum. This cured the evil for some time; 
but in a few years the leakage again appeared, and had increased so much in 
1867 that Mr. Bateman was brought over to examine it. He recommended 
as the only effectual remedy to the leakage to cut out the centre of the em- 
bankment down to the culvert, take away the rubble-backing and all loose 
material around the culvert, and erect perfectly water-tight walls closely 
connected with the existing masonry on each side of the puddle-trench. As 
it was then too late in the season to carry out this great work, he recom- 
mended as a temporary expedient to repeat the measures adopted in 1839, 
of puddling round the mouth of the inner culvert and caulking all its open 
joints, also, if necessary, to make good the concrete under the invert. The 
Directors of the Bann Reservoir Company were unwilling toincurthe expense 
of cutting out the centre of the embankment, as it would not only have cost 
a large sum for the work, but also have stopped the rates for at least a year. 
I was therefore requested to make the smaller work, recommended as tem- 
porary, if possible so effectual in moderating or stopping the leakage as to 
prevent recourse being had to the larger work. I had therefore a portion of 
the bank excavated so as to expose about six feet of the culvert close to the 
forebay or mouth, the concrete under the invert removed for about three feet, 
and a close wall of fire-brick and Portland cement built under and around 
the culvert, with which it was closely united. The excavation was then 
made up with puddle and dry peat, so staunch as to prevent access of water 
from the embankment to the backing of the culvert, and the old plan of 
caulking and cementing the open joints prevented the water getting to it 
through the inside of the arch. This caulking was not carried out as com- 
pletely as I wished, since it was then so late in the season that further delay 
in getting water into the reservoir would have been likely to entail serious 
loss ; so only the points that showed weakness were attended to, anda lining 
of cement applied to the whole of the inner culvert. 
The result was mostsatisfactory, asthe leakage was almost entirely stopped, 
and since then has given no trouble. The insignificant escape then left, 
although somewhat increased by the softening of the cement in some of the 
joints, may be stopped when a convenient opportunity occurs by caulking; or 
the difficulty of the imperfect masonry may be got over by continuing the 
iron pipes back to the mouth of the culvert, and securing them there by a 
solid plug of masonry. A portion of this leakage is probably derived from a 
spring, as it is harder than the water in the reservoir. A more detailed descrip- 
tion of these repairs may be found in a paper by me published in the ‘ Trans- 
actions of the Institution of Civil Engineers of Ireland,’ vol. ix. p. 51. 
Lough Island Reavy reservoir is 430 feet above the sea-level, and is mainly 
supplied from the Muddock river by a feeder of about one and a half mile 
