bought the freehold from the Duke of Norfolk's estate in 1798, and have run the mill ever since. The water-powered snuff grinding equipment remains in place, although it is no longer used to grind snuff commercially. Stalker Wheel also known as Three-Square Dams Lying between Ecclesall Road and the high wall stone wall of Sheffield General Cemetery. Sharrow Forge Drained and filled in, 1870. The land was developed to build houses in Napier Street and St Matthias Primary School. Broomhall Cornmill Also drained and filled in, 1870. Bennett's Wheel also known as Little Sheffield Moor or Vulcan Works Dam The original grinding wheel (1810–1851) closed and the dam was leased to the Vulcan Works a forge, and rolling-mill providing water for boilers. Leadmill Dam also known as Marriott's Wheel (1732–1780s). The White Lead Works was erected in 1759 producing pigments for paint and pottery glazes and continued in use until the later 19th century. When it closed, the dam was filled in and the site used to construct a tram-depot 1910. Ponds Lane Dam The Peak Park Anniversary Cycle Route follows the Porter Brook from Bingham Park to Porter Clough near Ringinglow. Water quality The brook derives its name from its brownish colour, similar to the colour of Porter beer. The discolouration is created as the water passes through and over local iron-ore deposits. The Environment Agency measure the water quality of the river systems in England. Each is given an overall ecological status, which may be one of five levels: high, good, moderate, poor and bad. There are several components that are used to determine this, including biological status, which looks at the quantity and varieties of invertebrates, angiosperms and fish. Chemical status, which compares the concentrations of various chemicals against known safe concentrations, is rated good or fail. The Porter Brook is designated as "heavily modified", which means that the channels have been altered by human activity, and the criteria for this designation are defined by the Water Framework Directive. The water quality of the Porter Brook was as follows in 2019. The water quality in the river has deteriorated since 2013, when it was rated good for ecological status. Like many rivers in the UK, the chemical status changed from good to fail in 2019, due to the presence of polybrominated diphenyl ethers (PBDE), perfluorooctane sulphonate (PFOS) and mercury compounds, none of which had previously been included