Construction of this dam was almost complete in 1864 when the wall was breached. Over 650 million gallons of water rushed down the Loxley valley towards Sheffield. Over 250 people were killed and hundreds of buildings were destroyed. Bodies were washed as far afield as Swinton near Rotherham. The disaster was recorded on photographs and lantern slides and thus became one of the first to reach national consciousness. The dam was later rebuilt. Legibility of the earlier landscape is invisible. The date of origin of the moorland is uncertain but it had probably developed in this area by the Roman period (see Bevan 2003 for discussion of environmental evidence in the area).