The river Dour is about four miles long with its main source at Watersend, near Temple Ewell. An estate map of 1774 shows a tributary coming in from the Alkham Valley but all that now remains of this stream are the lakes at Bushy Ruff, from where the stream flows into the main river at Kearsney Abbey. Sometimes though, at times of particularly heavy rain, this stream runs again, flowing over the fields to feed the Bushy Ruff lakes once more. From Kearsney Abbey the Dour flows on through the town until it reaches the Wellington Dock and then flows into the sea.It is to the Dour that Dover owes its existence. The valley cut by the river through the chalk cliffs provided shelter to the earliest settlers. The discovery of the Bronze Age Boat shows that the valley has been inhabited for at least 3550 years. In Roman times the wide estuary of the Dour made a convenient harbour, and for a while the Roman fleet in Britain was based here. The estuary was quite wide up to the time of the Norman Conquest but over the years it silted up and the harbour moved to the west of the river's mouth.It seems likely that the name of the town and the river come from the same root, although the two have parted company down the centuries as pronunciation and spelling changed.The Dour has had an industrial use since at least AD 762, when the first written record of a Dover corn mill was made. This mill, probably at Buckland, was also the first recorded mill in Britain. Over the years the Dour has supplied the energy for thirteen watermills, of which eight were corn mills, the others producing paper. The river has been a source of power or water for other industries, including iron foundries, saw mills and a tannery.