River Thames
The River Thames (/tɛmz/ ⓘ TEMZ), known alternatively in parts as the River Isis, is a river that flows through southern England including London. At 215 miles (346 km), it is the longest river entirely in England and the second-longest in the United Kingdom, after the River Severn.
"Thames" redirects here. For other uses, see Thames (disambiguation).River Thames
Proto-Celtic *tamēssa, possibly meaning "dark"
England
Cricklade, Lechlade, Oxford, Abingdon, Wallingford, Reading, Henley-on-Thames, Marlow, Maidenhead, Windsor, Staines-upon-Thames, Walton-on-Thames, Sunbury-on-Thames, Kingston upon Thames, London (inc. Twickenham, the City), Dagenham, Erith, Dartford, Grays, Gravesend
Thames Head, Gloucestershire, UK
110 m (360 ft)
Ullenwood, Gloucestershire, UK
214 m (702 ft)
Southend-on-Sea, Essex, UK
0 m (0 ft)
346 km (215 mi)
12,935 km2 (4,994 sq mi)
London
65.8 m3/s (2,320 cu ft/s)
370 m3/s (13,000 cu ft/s)
entering Oxford
17.6 m3/s (620 cu ft/s)
leaving Oxford
24.8 m3/s (880 cu ft/s)
39.7 m3/s (1,400 cu ft/s)
Windsor
59.3 m3/s (2,090 cu ft/s)
The river rises at Thames Head in Gloucestershire and flows into the North Sea near Tilbury, Essex and Gravesend, Kent, via the Thames Estuary. From the west, it flows through Oxford (where it is sometimes called the Isis), Reading, Henley-on-Thames and Windsor. The Thames also drains the whole of Greater London.[1]
The lower reaches of the river are called the Tideway, derived from its long tidal reach up to Teddington Lock. Its tidal section includes most of its London stretch and has a rise and fall of 23 ft (7 m). From Oxford to the estuary, the Thames drops by 55 metres (180 ft). Running through some of the drier 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. Its catchment area covers a large part of south-eastern and a small part of western England; the river is fed by at least 50 named tributaries. The river contains over 80 islands. With its waters varying from freshwater to almost seawater, the Thames supports a variety of wildlife and has a number of adjoining Sites of Special Scientific Interest, with the largest being in the North Kent Marshes and covering 20.4 sq mi (5,289 ha).[2]
Pollution[edit]
Treated and untreated sewage[edit]
Treated waste water from all the towns and villages in the Thames catchment flow into the Thames via sewage treatment plants. This includes all that from Swindon, Oxford, Berkshire and almost all of Surrey.
However, untreated sewage still often enters the Thames during wet weather. When London's sewerage system was built, sewers were designed to overflow through discharge points along the river during heavy storms. Originally, this would happen once or twice a year, however overflows now happen once a week on average.[79] In 2013, over 55m tonnes of dilute raw sewage overflowed into the tidal Thames. These discharge events kill fish, leave raw sewage on the riverbanks, and decrease the water quality of the river.[80][81] A 2022 investigation by the Environment Agency found "widespread and serious non-compliance with the relevant regulations".[82][83] Thames Water has also published an interactive map showing discharges as they happen.[84][85]
To reduce the release of this into the river, the Thames Tideway Scheme is currently under construction at a cost of £4.2 billion. This project will collect sewage from the Greater London area before it overflows, before channelling it down a 25 km (15 mi) tunnel underneath the tidal Thames, so that it can be treated at Beckton Sewage Treatment Works.[86][87] The project is planned to reduce sewage discharges into the Thames in the Greater London area by 90%, dramatically increasing water quality.[88] After its completion, it is estimated that two million tonnes of sewage will still enter the Thames each year.[89]
Mercury levels[edit]
Mercury (Hg) is an environmentally persistent heavy metal which can be toxic to marine life and humans. Sixty sediment cores of 1 m in depth, spanning the entire tidal River Thames between Brentford and the Isle of Grain, have been analysed for total Hg. The sediment records show a clear rise and fall of Hg pollution through history.[90] Mercury concentrations in the River Thames decrease downstream from London to the outer Estuary, with the total Hg levels ranging from 0.01 to 12.07 mg/kg, giving a mean of 2.10 mg/kg which is higher than many other UK and European river estuaries.[91][90]
The most sedimentary-hosted Hg pollution in the Thames estuary occurs in the central London area between Vauxhall Bridge and Woolwich.[90] The majority of sediment cores show a clear decrease in Hg concentrations close to the surface, which is attributed to an overall reduction in polluting activities as well as improved effectiveness of recent environmental legalisation and river management (e.g. Oslo-Paris convention).
Plastic pollution[edit]
The Thames has relatively high levels of plastic pollution, with an estimated 94,000 microplastics per second moving through some parts of the river. These microplastics come from the breakdown of larger items but also glitter and microbeads from cosmetics.[92]
One study found one-fifth of macroplastics found in the river were from food packaging.[93]
The Thames in the arts[edit]
Visual arts[edit]
The River Thames has been a subject for artists, great and minor, over the centuries. Four major artists with works based on the Thames are Canaletto, J. M. W. Turner, Claude Monet and James Abbott McNeill Whistler.[103] The 20th-century British artist Stanley Spencer produced many works at Cookham.[104]
John Kaufman's sculpture The Diver: Regeneration is sited in the Thames near Rainham.[105]
The river and bridges are portrayed as being destroyed – together with much of London – in the film Independence Day 2.[106]