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THE CONSTRUCTION OF BILBERRY RESERVOIR

Bilberry Reservoir was constructed in the year 1840, at the head of a narrow gorge or glen, leading from Holmebridge to the high bluff of land called Good Bent, and is supplied by two streams flowing through the cloughs, running to the north east and south east of Good Bent, and draining the moors of Holme Moss on the one side, and the hills running up to Saddleworth on the other, including some thousands of acres of moorland. 

The extent of the surface drained is estimated at 14,000 acres, which, reckoning at 2 inches of rain in twenty-four hours, would give 101,640,000 cubic feet of water. 

The confluence of the two streams takes place between two large hills, called Hoobroom Hill and Lumb Bank, and which run parallel with each other for a distance of about 150 yards, when they open out, and form an extensive oval basin of not less than three hundred yards in diameter. 

The reservoir was formed by blocking up the valley below this basin, so as to enclose some fifteen or twenty acres of surface.  Situated as it is, at the top of a narrow gauge or glen, it presented engineering difficulties of no common character.

These difficulties were taken into consideration to begin with, and Mr. George Leather, C.E., was engaged to prepare the plans and specifications. 

The construction of the reservoir was let to Messrs. Sharp and Sons, of Dewsbury, for £9,324 and the construction was proceeded with under this contract. 

The embankment was so formed that it was presumed it would constitute a barrier secure enough against any accumulation of water the heaviest rains could supply.

The embankment was about three hundred feet across, and about sixty seven feet high, and was formed of earth, stones, etc., such as the district supplied, with a wall of what is called “puddle” through its centre, sixteen feet thick at the bottom, and eight feet thick at the top.  This puddle was composed of clay, gravel, etc., and the object of introducing it was to render the embankment water tight, and so prevent leakage of the water. 

The bye-wash, or waste-pit, which was a circular chimney about five yards in diameter, was on the south or the right hand side of the reservoir, and was sunk through the embankment near to its junction with Hoobroom Hill, and communication with a tunnel, emptying itself on the lower or outer side of the embankment.  Its height from the bed of the reservoir was fifty-nine feet. 

The outlet of water was by an open culvert., along the bed of the reservoir, communicating with the tunnel referred to by two patent trap-doors, or shuttles, situated directly parallel to each other at the bottom of the chimney, and were worked by perpendicular rods raised by a common screw on a platform at the top of the chimney.  In the event of the trap door being insufficient to carry the surplus water away during extraordinary supplies, the water, on rising to the level of the chimney or bye-wash, would meet with a source of escape presumed to be adequate to all contingencies.

At a subsequent period the embankment considerably settled in one or two places near the centre, and its surface was thus lowered below the level of the bye-wash, which was thereby rendered useless for the taking away of surplus or flood water. 
Whilst the embankment was being constructed, a dispute arose with Messrs. Sharp and Sons, and the contract with them was broken.  Messrs. David Peter and Brothers undertook in 1848 to complete the work. 

It was stated at the time that in blasting the rock for the purpose of getting a firm foundation for the puddle-wall, the workmen struck into a spring about the thickness of a man’s arm, and instead of this being carried off so as not to interfere with the work, an attempt was made to carry it up the embankment, and force it into the inside. 

This injured the puddle by keeping it too soft, and it appears to have been the first great error in the construction of the embankment.  Mr Leather, the engineer, however, on the other hand, declared an oath before the coroner’s jury that he never heard of the spring; but the workmen declared that they waited five or six weeks for him to come and look at it, and that this delay cost the contractors £200 or £300. 
When Messrs.

Potter took the work in hand, they opened the embankment, and put in a great amount of material, with the view of preventing a rupture.  When the work had been going on for some time, they informed the Commissioner that they had got low enough, and that a further opening would have to be made, and more puddle put in if the evil was to be remedied. 

But the commissioners declined to go to further expense, as the construction of Homestyes and Boshaw Whams reservoirs, and sundry law expenses, had been so heavy.

Thus the embankment from the first was leaky, and these leaks increasing in number and power, caused the embankment to sink below the water pipe.  Sometimes these leaks were so serious that they would supply the mills without his having to attend to the shuttles.

In February, 1852, one of these shuttles was under repair, and the workman had suspended the work until he could learn who was to pay him his wages; and the other shuttle was so blocked up with stones, ling, &c., that very little water would escape.  This was the condition of the shuttles on the night of the 4^th of February, 1852.