   the river rother, a waterway in the northern midlands of england, gives its name to the town of rotherham and to the rother valley parliamentary constituency. it rises near clay cross in derbyshire and flows in a generally northwards direction through the centre of chesterfield, where it feeds the chesterfield canal, and on through the rother valley country park and several districts of sheffield before joining the river don at rotherham in yorkshire. from the 1880s the water quality deteriorated rapidly, as a result of coal mining and its associated communities. the river became unable to sustain life, and by 1974, was the most polluted of the rivers within the river don catchment. the pollutants came from coking plants, from inefficient sewage treatment plants, and from the manufacture of chemicals. major investment in upgrading the sewage treatment works took place, and in the treatment of industrial effluent before it was discharged to the river. the closure of the main coking plants has also aided the recovery of the river, and enabled restocking with fish to begin in 1994. by 1996 there was evidence for self-sustaining fish populations, and the river  supports organised angling. a short section of the river in chesterfield was once navigable, and may become so again as part of a development project, while there are plans to use the course from rother valley country park to rotherham for the rother link, which would connect the chesterfield canal to the river don navigation. the lower river is managed because of flood risk: three regulators can restrict its flow. their operation normally causes flooding of washlands, rather than of centres of population, which might otherwise be inundated. ==course== the source of the river is at pilsley near clay cross in derbyshire, from where it flows to the west for a short distance, before turning to the north. the valley is shared with the derby to rotherham railway, which makes the first two of a total of 20 crossings before the river reaches the eastern edges of danesmoor. it is joined by another stream before passing to the west of north wingfield, after which the red lead mill brook joins from the west. before reaching [[chesterfield, england
Rivers_of_Derbyshire Rivers_of_Rotherham Rivers_of_Sheffield Tributaries_of_the_River_Ouse,_Yorkshire