Sheffield has a poor track-record for civic monuments.

Apart from the statue of King Edward VII standing in recently spruced-up surroundings in Fitzalan Square, most of the other monuments that once graced the centre have been shipped off to suburban parks or, in the case of the Crimea Monument, dismantled:  https://www.victoriansociety.org.uk/news/sheffields-missing-crimean-war-monument.

Indeed, until recently there was no monument of any significance to those who lost their lives in the most dramatic incident in the history of Sheffield, the Great Sheffield Flood of 1864.

The Sheffield Waterworks Company, desperately trying to keep up with accelerating demand from the rapidly growing steel industry and the expanding population, devised a scheme to capture the waters of the Loxley Valley, north-west of the town.

The first of three planned reservoirs, Dale Dike, was begun in 1859 and, after its alignment had been altered to avoid unexpected disturbed strata, it was completed and filled by early 1864.

No sooner had the waters reached within two feet of the lip of the dam than cracks appeared and, within a day, the dam collapsed at 11.30pm on March 11th 1864, sending 700 million gallons of water down the Loxley Valley at a speed of around 18 miles an hour.  At least 250 people were killed, including 27 whose bodies were never recovered.  Around 800 houses were destroyed or abandoned and well over 4,000 flooded.

There was no firm agreement over the cause of the disaster, at least partly because of the Coroner’s intemperate handling of the inquest.  Among the possible contributory causes were –

• slippage of unstable strata beneath the embankment
• poor construction of the embankment surrounding the clay core
• inadequate thickness of the clay core
• settlement or undue pressure leading to fracture around the outlet pipes and consequent leakage

The jury’s verdict was that “there has not been that engineering skill and that attention to the construction of the works, which their magnitude and importance demanded…” and they went on to propose that “the Legislature ought to take such action as will result in a governmental inspection of all works of this character;  and, that such inspection should be frequent, sufficient and regular…”

Such legislation was eventually passed – the Reservoirs (Safety Provisions) Act (1930). 

Although designed in the same way as the failed dam, Agden Dam was resumed and its 629,000,000-gallon reservoir completed in 1869.  Further upstream, the Strines Reservoir (513,000,000 gallons) was finished in 1871. 

The new Dale Dyke Dam, a quarter of a mile upstream from the site of the original, was completed in 1875, though the reservoir was not brought fully into use until 1887.   It holds 446,000,000 gallons.

The final Loxley valley reservoir, Damflask, which holds 1,158,000,000 gallons, initially intended for use as compensation water, was constructed in the late 1870s but because of leakage through the strata at one side was not fully operational until a wing-trench was completed in 1896.

For many years the only physical memento of the original Dale Dyke Dam was a marker stone inscribed “CLOB” – Centre Line Old Bank – indicating the alignment of the 1864 dam.

For the 150th anniversary of the disaster, the Bradfield Historical Society cleared a trail around the reservoir and put up a memorial to the victims of the flood.

The Sheffield & Rotherham Wildlife Trust has produced a superb film about Sheffield’s vulnerability to flooding, with contributions from two particularly knowledgeable local historians, Ron Clayton and Malcolm Nunn: TORRENT: Sheffield’s Flood Story | FULL DOCUMENTARY! | Sheffield & Rotherham Wildlife Trust – YouTube.