Beyond Forge Dam, where the Porter is defined as a main river, the brook passes Wire Mill Dam, where there is a monument celebrating the life of Thomas Boulsover, the inventor of Sheffield Plate. The grade II listed structure was constructed in 1927 by a Master Cutler called David Flather, and may have been built from materials taken from the Wire Mill. Below Whiteley Wood Road bridge it is joined by a small tributary, flowing northwards from springs in the Porter Valley Woodlands Nature Reserve. Next it reaches Hangingwater Road bridge, a massive structure built around 1800, with two small segmental arches. Immediately below the bridge is the dam for Shepherd's Wheel, with the buildings at its downstream end. The dam, goit, buildings and weir are grade II* listed, as internally, the machinery is complete and still operational. The site is run as a museum.