Thames (tĕmz) [key], Rom. Tamesis, principal river of England, c.210 mi (340 km) long. It rises in four headstreams (the Thames or Isis, Churn, Coln, and Leach) in the Cotswold Hills, E Gloucestershire, and flows generally eastward across S England and through London to the North Sea at The Nore. In its upper course—around and above Oxford—it is often called Isis. The Thames drains c.5,250 sq mi (13,600 sq km); its tributaries include the Windrush, Cherwell, Thame, Kennet, Wey, Mole, Lea, Roding, and Medway. It is joined by canals (including the Oxford, Thames and Severn, and Grand Junction) that cover a wide area. The river is navigable by barges to Lechlade, below which there are a number of locks. The Thames is tidal to Teddington; there is a 23-ft (7-m) difference between low and high tide at London Bridge. The part of the stream near London Bridge is known as the Pool. The main part of the port of London stretches from London Bridge to Blackwall. The Thames Conservancy Board was established in 1857; the docks and the tidal part of the river below Teddington have been administered by the Port of London Authority since 1908. Part of the river is of great beauty, is much used for boating, and is still popular for fishing. The upper valley of the Thames is a broad, flat basin of alluvial clay soil, through which the river winds and turns constantly in all directions. At Goring Gap the valley narrows, separating the Chiltern Hills from the Berkshire Downs. The lower valley forms a second broad basin through which the Thames also meanders. The land around the river was formerly marshy, and the ancient roads were far from the river banks. In the Middle Ages the valley was very prosperous, with many religious houses and several large towns, including Reading and Windsor. Between Oxford and London, the valley is predominantly agricultural, with scattered villages; Reading is the only industrial town there. The Greater London conurbation along the river's lower course is one of the most important industrial regions of Great Britain. Among the many interesting archaeological discoveries made in the valley are fossils of seashells and a human skull from the Paleolithic period. In London the river is crossed by 27 bridges, including the new London Bridge, Westminster Bridge, Waterloo Bridge, and Tower Bridge. There are two main tunnels under the river in London, and one between Dartford and Purfleet, as well as several footpaths and 5 railroad tunnels. In 1963 governmental efforts began to combat pollution of the waters through a series of rules and regulations. At parts along the river downstream flood barriers were constructed, which became operational in 1982, to prevent London from damage by North Sea gales.
See study by J. Schneer (2005).