On this day in history : 11th March 1864 – The Great Sheffield Flood devastates parts of Sheffield, when the Dale Dyke Dam collapses – claiming the lives of over 240 people….
It was as people slept in their beds, at just before midnight, that a raging torrent of water smashed into their homes…. Most were killed instantly as their houses were washed away…. 700 million gallons of water had swept down the Loxley and Don Valleys from the gigantic reservoir at Bradfield….
The Bradfield Reservoir had only recently been completed…. Built by the Sheffield Waterworks Company between 1859 and 1864 it had been constructed to supply the mills located across the Loxley Valley and to supply water to the city of Sheffield, about 8 miles away…. The population of Sheffield had grown rapidly in the previous 60 years, from 45,478 in 1801 to 185,157 in 1861 – so more water was desperately needed…. The water in the reservoir, which was 90ft deep in places, was held back by the Dale Dyke Dam….
The reservoir was being filled for the first time…. Around 5.30pm on the evening of the 11th William Horsefield, a quarrymen, noticed a small crack in the embankment and he reported it to local workmen…. By 7pm the crack had opened up to about an inch or so and word was sent to alert the dam’s engineer, John Gunson…. He arrived at the site just after 10pm – and thinking that he could relieve the pressure proceeded to blow-up the waste water weir…. However, in less than two hours the dam had breached….
In just over three-quarters of an hour the reservoir had emptied…. Water cascaded down the hillside at nearly 20mph….it was impossible to warn people in the valley below…. Settlements at Loxley, Bradfield, Little Matlock, Main Bridge, Damflask and countless of others were swept clean away – as were the mills and farms between them…. More than 5,000 dwellings and businesses were lost….
When it reached Sheffield the water rose to as much as 4ft deep…. Of those killed – which was at least 228 but could have been as many as 280 – the youngest was just two days old….
The following days saw a succession of onlookers wanting to see the devastation – with extra trains being laid on to bring the sightseers…. Hot chestnuts were sold on the roadside! A relief fund was set up to which Queen Victoria personally donated £200….
The dam was rebuilt in 1875….
The government faced more than 7,000 compensation claims totalling over £450,000…. A government inspector’s report found the dam’s collapse to be the fault of John Gunson and another named John Leather…. The verdict at the inquiry cited a ‘lack of engineering skill and construction of the works’…. However, a study conducted in the 1980s, over 100 years after the tragedy, found the exact cause was down to problems with the water tight barrier in the embankment….