page_title: River Thames
section_title: Navigation
hierarchical_section_title: River Thames / The active river / Navigation
caption_attribution_description: English: A Rubbish Trap on the River Thames near the Millenium Bridge in the central London, England.
context_page_description: The River Thames, known alternatively in parts as the Isis, is a river that flows through southern England including London. At 215 miles, it is the longest river entirely in England and the second-longest in the United Kingdom, after the River Severn.
  It flows through Oxford, Reading, Henley-on-Thames and Windsor. The lower reaches of the river are called the Tideway, derived from its long tidal reach up to Teddington Lock. It rises at Thames Head in Gloucestershire, and flows into the North Sea via the Thames Estuary. The Thames drains the whole of Greater London.
  Its tidal section, reaching up to Teddington Lock, includes most of its London stretch and has a rise and fall of 23 feet. Running through some of the driest parts of mainland Britain and heavily abstracted for drinking water, the Thames' discharge is low considering its length and breadth: the Severn has a discharge almost twice as large on average despite having a smaller drainage basin. In Scotland, the Tay achieves more than double the Thames' average discharge from a drainage basin that is 60% smaller.
  Along its course are 45 navigation locks with accompanying weirs.
context_section_description: The Thames is maintained for navigation by powered craft from the estuary as far as Lechlade in Gloucestershire and for very small craft to Cricklade. The original towpath extends upstream from Putney Bridge as far as the connection with the now disused Thames and Severn Canal at Inglesham, one and a half miles  upstream of the last boat lock near Lechlade. From Teddington Lock to the head of navigation, the navigation authority is the Environment Agency. Between the sea and Teddington Lock, the river forms part of the Port of London and navigation is administered by the Port of London Authority. Both the tidal river through London and the non-tidal river upstream are intensively used for leisure navigation.
  The non-tidal River Thames is divided into reaches by the 45 locks. The locks are staffed for the greater part of the day, but can be operated by experienced users out of hours. This part of the Thames links to existing navigations at the River Wey Navigation, the River Kennet and the Oxford Canal. All craft using it must be licensed. The Environment Agency has patrol boats (named after tributaries of the Thames) and can enforce the limit strictly since river traffic usually has to pass through a lock at some stage. A speed limit of 8 km/h (4.3 kn) applies. There are pairs of transit markers at various points along the non-tidal river that can be used to check speed – a boat travelling legally taking a minute or more to pass between the two markers.
  The tidal river is navigable to large ocean-going ships as far upstream as the Pool of London and London Bridge. Although London's upstream enclosed docks have closed and central London sees only the occasional visiting cruise ship or warship, the tidal river remains one of Britain's main ports. Around 60 active terminals cater for shipping of all types including ro-ro ferries, cruise liners and vessels carrying containers, vehicles, timber, grain, paper, crude oil, petroleum products, liquified petroleum gas etc. There is a regular traffic of aggregate or refuse vessels, operating from wharves in the west of London. The tidal Thames links to the canal network at the River Lea Navigation, the Regent's Canal at Limehouse Basin and the Grand Union Canal at Brentford.
  Upstream of Wandsworth Bridge a speed limit of 8 knots (15 km/h) is in force for powered craft to protect the riverbank environment and to provide safe conditions for rowers and other river users. There is no absolute speed limit on most of the Tideway downstream of Wandsworth Bridge, although boats are not allowed to create undue wash. Powered boats are limited to 12 knots between Lambeth Bridge and downstream of Tower Bridge, with some exceptions. Boats can be approved by the harbour master to travel at speeds of up to 30 knots from below Tower Bridge to past the Thames Barrier.
caption: Rubbish traps are used on the Thames to filter debris as it flows through central London
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