The following information is taken from a news article (origin unknown) entitled, "The Sheffield Flood; An Old Story Re-Told".
The flood occurred on the night of Friday, 11th March 1864 when the Dale Dyke, or Bradfield Reservoir, burst. The Dyke was situated about eight miles from Sheffield and a little over a mile to the west of Bradfield. When the accident occurred, the dam had scarcely been completed, building having been started in 1859. The embankment was 500 wide at the base, 100 feet high and 12 feet wide at the summit. The building of the dam came about due to the need for a more regular supply of water to the town. However, the reservoir was filled too early and that, combined with particularly stormy weather at the time, caused the water to overflow the dam, resulting in a crack appearing in the embankment.
The disaster resulted in the greatest loss of life in England as a result of flooding of inland waters to that date. At least 250 people were killed, with bodies still being discovered months after the flood had occurred. Destruction of property was vast. According to the news report, 117 manufactories, 43 mills, 46 shops, 4,501 houses, 163 workshops, 186 malthouses, breweries, public houses and beerhouses, 11 churches, chapels and schools, 3 tanneries and skin yards; 135 other buildings; 20 bridges; 4,478 yards of fence walling; and 287 cottage and market gardens were either flooded, partially destroyed, or wholly destroyed. 4,357 houses were flooded , 798 being absolutely destroyed and abandoned.
The following section gives details of the effect of the flood on the school and schoolhouse which were located in the village of Lower Bradfield:"The village schoolmaster at Lower Bradfield a quarter of a century ago was Mr. Nicholls. His school and school-house were just below the corn-mill, at the lower corner of the school bridge, on the left bank of the river. Between the river and the school buildings was a narrow garden. On the left ran the turnpike road, just where the dozen stone steps leading from the miller's residence abuts upon it. Nicholls, as already related, had accompanied Barrett and William Ibbetson up to the embankment in the early part of the evening. Nicholls was one of those who had had previous misgivings concerning the dam, but returned home about ten o'clock that Friday night under the belief that the evil hour had not yet arrived. He was going off to bed when he noted the anxious face of his wife, who, as she said, "could not get the dam out of her head." The family, therefore, sat up around the fire talking the chances over. "Let us go and see if there is more water in the river," said Mrs. Nicholls, and the family adjourned to the outside of the house. Standing on the school bridge they narrowly watched the water. Up to ten minutes before the flood poured down they had concluded that the watercourse was no fuller than usual. Then all at once there was a very perceptible increase, owing, as was afterwards accounted for, by the water flowing through the 18-inch open pipes at the foot of the great reservoir. Still they were not greatly alarmed. Back into the house the husband and wife went. "Now, Jane, let us off to bed," cried Nicholls, "the flood's not coming off to-night." But the wife was still undecided. Throwing more coal upon the fire, Jane replied, "When this fire is burnt down, then I'll go to bed; not before." A moment after she looked out of a window on to the river, and exclaimed in terror, "Here's the flood. The water's rising fast. It's getting up to the trees by our garden hedge." Sure enough the lady was right. Before anything more could be said or done William Ibbetson was thundering at the door, and shouting, "Escape for your lives! The flood's here at last!" Husband and wife rushed out on to the turnpike road, crossed it, and ran up the dozen stone steps previously alluded to as leading to the miller's house. They were just in time. The flood was even then almost at their very heels. Nicholls, half-way up the steps, turned back, sprang across the road once more and into the house, and brought out his top coat. Mrs. Nicholls never expected to see her husband again alive. For in his absence she noted, from her elevated position near the miller's house, that the flood in immense volume was almost upon them. It was a narrow escape for the schoolmaster. As he mounted the steps a second time, Mr. Nicholls felt the spray from the flooded water blown into his face. A moment later, and he would have been catalogued as the "second human victim" of the memorable flood. The large school and everything it contained - books, educational apparatus - all were swept away a moment after the corn-mill went down, along with the two-storied schoolmaster's house. Not a vestige remained of premises which had been partly rebuilt only the year before at a cost of nearly £300. The school bridge was swept away at the same moment. Lookers-on at the time remarked that as the corn-mill vanished the bridge was seen to go, and then, the next moment, the school buildings. Sixteen years after that eventful night, when labourers were altering the course of the Loxley stream some hundred yards or so lower down, they disinterred a pair of tongs and some pence and halfpence from the bed of the stream. The tongs were recognised on the spot as those which had been bought by Mrs. Nicholls only a fortnight before the flood. They are now in the possession of Mrs. Barrett, the village postmaster, who suggests that the authorities at Weston Park Museum may have them for the asking to place beside other relics of the great disaster of 1864. Beside these tongs and money - joiners' tools, carried down from Mr. Wilson's shop, and chains and tires from the smithy, were found in the bed of the stream at the same time. When a new school was erected it was thought judicious to build it on elevated ground at the higher end of the village, far out of the reach of any possible future flood, and there it stands to this day."
Further information on the flood may be found here: