14K) 



FLOODS AT THE MANCHESTER WATERWORKS 



amount of pressure on the discharge pipes in case of neces- 

 sity. On the 7th a very heavy fall of rain, accompanied with 

 a hurricane from the north-east, occasioned a flood which set 

 at nought all previous calculations. When at its highest it 

 amounted to upwards of 4,000 cubic feet per second, being 

 at the rate of upwards of 50 feet per second for every 100 

 acres. After attaining this height, it flowed for the following 

 three hours at an average of 1,800 feet per second. A weir 

 on the watercourse across the Heyden Brook, which was not 

 quite finished, but which had been considered sufficiently so 

 to secure the safe passage of the water, was absolutely beaten 

 down by the force of wind and water, and a breach being 

 made through which the water passed, the watercourse was 

 thus rendered useless. The water poured into the basin of 

 the reservoir, and speedily overtopped the newly-formed piece 

 of embankment. It had been raised to a height of 24 feet, 

 and was raised 3 feet more during the progress of the flood, 

 so that when the water reached the top it was 27 feet high. 

 The bank was not long in being cut down, and a quantity of 

 water amounting to about 14,000,000 cubic feet was set at 

 once at liberty. For a short distance it carried all before it, 

 and did more or less damage for four or five miles down the 

 river. No serious mischief, however, was sustained, and 

 happily no lives were lost. The quantity of water which was 

 impounded at the time of the accident was about equal to 

 that contained in the unfortunate Bilbury Reservoir, near 

 Holmfirth, which burst on the 5th of February and did 

 such fearful injury in the valley below. The difference in 

 the circumstances of the two cases easily accounts for the 

 difference in the two results. The depth of the water in the 

 Bilbury Reservoir was about 80 feet ; at Woodhead it was 

 27 feet only. The embankment of the Bilbury Reservoir, 

 owing to its peculiar construction, gave way in a great mass 

 at once, and the valley into which this mighty wall of waters 

 was instantaneously hurled is a steep and narrow ravine, down 



