It is well known that a region´s agriculture, economy and demographic repartition are often intertwined with its water bodies, as water sources are crucial for a number of important activities. From irrigation to navigation and building water mills, rivers have provided a propitious environment for survival since Kent´s earliest stages of human development. In terms of formation, the rivers flowing through Kent are mainly chalk rivers, which are prevalent in the south-east of England and are of superior quality in many regards. They sustain a highly diverse biocoenosis, which has also played its role in the subsistence of local communities throughout the centuries. Fish species such as trout (brown trout in particular) and salmon thrive in chalk rivers, besides a number of other wildlife species which are almost exclusive to this biotope, such as the white-clawed crayfish. Although there is a definite change in these environments due to the development of human habitats and their increasing needs, efforts are being made in order to preserve chalk rivers and halt those modifications.
Two rivers, Thames and Rother, have a limited impact on Kent as they only border it for along a relatively small area. As its source is located in East Sussex, River Rother juxtaposes with a short fraction of its border with Kent and flows into the English Channel at Rye Bay. River Rother is only partially navigable. In a similar manner, the River Thames is situated on Kent´s northern extremity, close to the point where it flows into the English Channel. The main rivers in Kent are Medway, Stour, Darent and Dour, with their many tributaries.
River Medway. The main river in Kent, it measures approximately 70 miles and enters the county through its western extremity, flowing eastwards and then towards the north east, finally reaching the North Sea, where it flows through the Thames Estuary. Throughout history it has been only partially navigable, between certain municipalities, and repeated operations were carried out in order to expand the navigable channel, such as those of 1746, 1792 or 1828. No less than nine crossings were built across it (six bridges - one dating from Roman times and refortified during the Middle Ages, two viaducts and a tunnel). Altogether, River Medway has got 9 tributaries, consisting of six rivers — Eden, Len, Bourne, Teise, Beult, Bewl, and tree streams — Loose, East Malling and Wateringbury. The river has also been used for economic as well as military purposes by invaders (for the latter, a notable example was the 43 AD Battle of Medway).
River Stour. Second in length and importance is the River Stour, which flows eastwards over 47 miles, from a location near Lenham village to Pegwell Bay were it connects to the North Sea. The toponymy of this river and its many tributaries is rather confusing as the river itself is devised into three segments, the Upper Great Stour, the Lower Great Stour and the River Stour, whereas two of its tributaries share the name as well, the East Stour and Little Stour. Aside from them, the river has got other 12 tributaries, the main ones being Nailbourne, Sarre Penn and River Wantsum. Three cities of major interest are located beside the Stour, namely Canterbury, Ashford and Sandwich, one of the historic Cinque Ports. The river is also renowned for its water milling and fishing.
River Darent. Originating from the vicinity of Westerham, near Kent´s western border, the River Darent flows northwards towards the River Thames, to which it is a tributary. Along its course it joins the river Cray, before finally reaching the Thames near Dartford. The river´s tributaries consist of 7 streams, namely those at Bradbourne, Ightham, Brasted, Chevening , plus Greatness Stream, Cranpit Stream and Guzzlebrook Stream. River Darent is particularly renowned for its notable economic role, due to the multitude of water mills located along its course.
River Dour. Dour is considerably shorter, as it measures approximately 4 kilometres, yet is significant due to its geographical position, as it flows into the English Channel at Dover. It is fed by two sources, one of them located near the village of Temple Ewel and the other one in close proximity, near the village of River, probably named after it. A single bridge was built across it, namely Buckland Bridge, situated to the left of Buckland village. River Dour presents a particular interest due to its estuary, of significant importance for the ancient Roman conquerors of Kent and developers of Dover. It was intensely used for navigation, as a natural port. A large number of water mills are located along River Dour as well.
Aside from natural waterways, in order to facilitate navigation, a number of projects were designed by local authorities towards developing more navigable canals in Kent, aside from the existing ones, yet were never completed. Another one, the Thames and Medway Canal, was used intensely during the 19th Century yet abandoned afterwards. The only currently in use are Dartford and Crayford Navigation and the Royal Military Canal.
Royal Military Canal. The canal is located in the western region of Kent and it partially crosses the border into Sussex, although merely for half a mile. As the name suggests, this canal was projected for a defensive role in a potential military conflict with France, during Napoleon´s policy of expansion of his French Empire. During early 19th century, its status was changed and regular navigation was initiated. It is 19 miles long and connects with the River Rother, running from Idem Lock (the merger point) to Hythe, where it flows into the North Sea.
Dartford and Crayford Navigation. Constituting the natural border between the district of London and Kent, it measures less than three miles (two miles and three quarters) and consists of the joined waters of River Darent and River Cray, which merge at Dartford Lock. The project was developed for four years and finally finished in 1844.
Thames and Medway Canal. Built in various phases between the municipality of Strood, which lies on the River Medway, and that of Gravesend, on the River Thames, the canal is no longer in use today. It was navigated on between its opening year , 1824, partially abandoned in 1847 and completely disused by 1934.