The flood occurred when the Dale Dyke Dam, under construction above Low Bradfield on the River Loxley burst. This sent huges waves of water flooding down the valley, through Loxley and Hillsborough, and then down the River Don through central Sheffield, Attercliffe and as far as Rotherham. The estimated seven hundred million gallons of water destroyed eight hundred houses, killing 270 people, and wrecking every bridge as far as the Lady’s Bridge in the city centre.