Building record MDR9942 - Masson Weir, Matlock Bath

Bowed weir across the Derwent at Masson Mill, circa 1780/84 (Arkwright). Built up on the foundations of an older weir destroyed by flood in approximately 1774. The downstream 'bow' of the weir is unusual, as most 19th century weirs upon fast current rivers were built with the bow upstream as at Belper and Milford. (1) The weir at Masson Mill is thought to have been built in its unusual convex shape because of the underlying rock structure at this point in the river. It is likely to have been an early addition to the Masson site, if not contemporary with the mill itself, which was completed by 1783. The earlier paper mill on part of this site would not have justified the construction of a weir on this scale. (2)