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end of the Reservoir, but this has no important bearing on the 

 subject under discussion. There may, however, be a third fault at 

 right angles to the others and running along the original bed of the 

 rivulet ; but I am at present inclined to think that the apparent 

 break in the mudstone rocks is merely one of the results of the sub- 

 aerial erosion by which the existing valley has been chiefly formed. 



It will be readily seen that in the first instance an unfortunate 

 selection of a site was made, a site which would have been objection- 

 able for any reservoir, and especially so for one which required so high 

 an embankment to hold back the necessary quantity of water. 

 Whether any geological examination of the spot was made I do not 

 know, but I imagine that the engineer was attracted by the favour- 

 able surface configuration, and did not suspect that its weakness lay 

 in its apparent strength. But it was not alone the selection of the 

 site that was in fault. Had no other mistakes been made it is quite 

 possible that the Reservoir might have done good service up to the 

 present time, though there would always have been a danger of from 

 leakage from the cause which I have described. The next mistake 

 was the laying a line of iron pipes under an earthen embankment. 

 This was quite a common practice at the time, as was shown at the 

 inquiry held after the bursting of the Sheffield reservoir ; but here 

 the pipes were not only laid under the embankment, but they were 

 supported by piers of masonry at intervals, which precipitated the 

 inevitable disaster. The unequal pressure caused by the irregular 

 settlement of the sand and clay after a time cracked the pipes, the 

 fracture being only discovered by a leakage near the outlet at the 

 bottom of the dam. Previously to this, as far as I can ascertain, 

 the inner slope of the dam had been lined with a facing of large 

 stones, and this facing, though intended for quite another purpose, 

 aided materially in preventing any serious damage to the properties 

 situated below the embankment when the final catastrophe took 

 place. 



The particulars of the last stage in the history of the reservoir, I 

 have gathered from different sources, having had no personal 

 knowledge of what was done until after the event. It seems that 

 when the fracture of the outlet pipes was discovered, it was decided 

 to make a drift-way or tunnel through the dam in order to discover 

 and repair the breakage, and this drift-way was actually carried 

 through the dam to within a few feet of its inner face. For some 

 40 feet, or thereabouts, from the entrance, it was lined with ashlar 

 masonry, but the rest— -the most dangerous part — was merely lined 

 with sawn timber, placed at intervals to support the sides and roof. 

 The result which followed was inevitable, though it might be delayed 

 for a time. Gradually the water found its way either through cracks 

 in the puddle wall, or along the line of piping, into the tunnel, 

 carrying out in solution the clay and earth which intervened 

 between the pressure and the point of least resistance, until the 

 timbered end of the tmmel caved in, and allowed it a free exit. I 

 have not been able to ascertain what depth of water there was in 

 the reservoir at the time, but there was evidently a considerable 

 pressure, and sufficient to have caused a destructive flood if it had 

 not been for the stone lined portion of the tunnel, and the stone 

 facing of the dam which I have referred to above. But for the 

 letter, the water would probably have entered the tunnel in volume 



