by the flood, but although steam power was gradually replacing water power elsewhere, most of those rebuilt continued to use water power, at least in part. Although the mill buildings have mostly gone, several of the weirs and dams remain, and there are still water wheels at Malin Bridge corn mill and Low Matlock rolling mill. Low Matlock Wheel is first mentioned in 1732, when James Balguy leased some land to build a cutlers wheel. The size of the wheel and the number of grinding troughs were left to his discretion, and so were not mentioned in the deeds. By 1825, the site was described as having three works, the first containing two tilt hammers, the second, two forges, and the third, two more tilt hammers and a plating hammer. The site was extensively damaged by the 1864 flood, and the owners put in a claim for over £5,000 to repair the damage. The present buildings carry the date 1882, and the rolling mill is a grade II* listed structure. Water power continued to be used until 1956, after which much of the internal machinery was retained but adapted to allow electric power to drive it. Following the sale in 1999 of most of the site for development, the rolling mill was bought by Pro-Roll Ltd, who were using teams of four men to roll high-value bar by hand in 2006. An archaeological excavation of part of the site took place in 2001, prior to redevelopment. The upper river valley is now the site of Damflask reservoir, built in the 1870s, but not completed until 1896, due to problems with leakage. It covered the sites of Dam Flask Corn Mill, which was probably part of the complex mentioned in 1219, and Dam Flask Wheel, which was variously a cutlers' wheel, a paper mill, and a scythe and sickle manufactory, between 1750 and 1861. By 1864 it was probably a wire mill, as four wire-drawers were drowned there in the flood. Water quality The Environment Agency measure 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