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The dam keeper's family lived directly below the reservoir. John Gunson had repo
1864 Event

March 11

Great Sheffield Flood: Dam Bursts, Over 250 Die in England's Worst Man-Made Disaster

The dam keeper's family lived directly below the reservoir. John Gunson had reported cracks in the Dale Dyke Dam embankment for days, but the Sheffield Waterworks Company's engineer dismissed his concerns. At 11:30 PM on March 11th, 1864, Gunson heard a sound like thunder and ran—the dam burst released 700 million gallons in minutes, sending a wall of water forty feet high down the Loughrigg Valley. Over 250 dead. Entire families swept away in their beds. The company had rushed construction to meet demand, filling the reservoir before the mortar fully cured. Parliament passed the Reservoirs Act five years later, but here's the thing: Gunson survived—he'd built his own house on slightly higher ground.

March 11, 1864

162 years ago

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