Thames
River
The Thames in London
Country	England
Counties	Gloucestershire, Wiltshire, Oxfordshire, Berkshire, Buckinghamshire, Surrey, Essex, Kent
Metropolitan County	Greater London
Towns/Cities	Cricklade, Lechlade, Oxford, Abingdon, Wallingford, Reading, Henley on Thames, Marlow, Maidenhead, Windsor, Staines-upon-Thames, Walton on Thames, Kingston upon Thames, Teddington, London, Dartford
Source
- location	Thames Head, Gloucestershire, UK
- elevation	110 m (361 ft)
- coordinates	51°41′39″N 2°01′47″W / 51.694262°N 2.029724°W / 51.694262; -2.029724
Mouth	Thames Estuary, North Sea
- location	Southend-on-Sea, Essex, UK
- elevation	0 m (0 ft)
- coordinates	51°29′56″N 0°36′31″E / 51.4989°N 0.6087°E / 51.4989; 0.6087
Length	346 km (215 mi)
Basin	12,935 km2 (4,994 sq mi)
Discharge	for London
- average	65.8 m3/s (2,324 cu ft/s)
Discharge elsewhere (average)
- entering Oxford	17.6 m3/s (622 cu ft/s)
- leaving Oxford	24.8 m3/s (876 cu ft/s)
- Reading	39.7 m3/s (1,402 cu ft/s)
- Windsor	59.3 m3/s (2,094 cu ft/s)

[ v t e ] Thames route map

Legend 235.84 Source of the Thames 235.06 Thames Head Bridge (A433 - Fosse Way) 233.97 A429 Bridge 216.81 A419 Bridge, Cricklade 200.96 Limit of navigation 200.83 River Coln 199.72 Ha'penny Bridge, Lechlade (A361) 199.65 St John's LockLast lock on the river; 71 m ASL 173.18 River Windrush 159.34 River Evenlode 155.46 Thames (Oxford By-pass) Bridge (A34) 148.88 River Cherwell, Oxford 146.83 Isis Bridge - Oxford Ring Road (A423) 143.34 River Thame, Dorchester-on-Thames 136.47 Abingdon Bridge, Abingdon (A415) 131.02 Appleford Railway Bridge (GWR to Birmingham) 115.41 Wallingford Bridge, Wallingford 110.10 Moulsford Railway Bridge (GWR to Bristol) 105.94 Goring Bridge (GWR to Bristol) 89.74 Caversham Bridge, Reading (A4155) 87.41 River Kennet & Kennet and Avon Canal 79.24 River Loddon, Wargrave 73.72 Henley Bridge (A4130) 60.04 Marlow By-pass Bridge, Marlow, (A404) 49.10 Maidenhead Railway Bridge (GWR to Bristol) 46.67 M4 Bridge 38.91 Windsor Bridge, Eton & Windsor 28.46 River Colne (Upper mouth) 28.45 Runnymede Bridges, Staines-upon-Thames (A30 & M25) 27.70 River Colne (Lower mouth), Staines-upon-Thames 21.34 M3 Bridge, Chertsey 11.08 River Wey and Wey Navigation, Weybridge 7.82 Hampton Court Bridge (A309) 7.45 River Mole, Hampton Court 0.64 Teddington Lock, Weir & BridgesTidal limit 0.0 Teddington Boundary Stone (PLA / DoE) -4.52 Twickenham Bridge (A316) -4.80 Richmond Lock and Footbridge -7.71 River Brent/Grand Union Canal -8.80 Kew Bridge, South Circular Road (A205) -10.86 Chiswick Bridge (A316) -17.84 Putney Bridge, (A219) -18.95 River Wandle -20.84 Battersea Railway Bridge -21.88 Battersea Bridge, (A3220) -23.66 Victoria Railway Bridge -25.24 Vauxhall Bridge (A202) -27.35 Charing Cross Bridge & Station (South Coast) -28.63 Blackfriars R'way bridge/station (Thameslink) -29.80 London Bridge (A3)8.7 m headway -30.69 Tower Bridge (A100)42.5  m headway -33.65 Regent's Canal -40.08 Blackwall Tunnel (A102) -41.06 Bow Creek, River Lea -43.51 Thames Barrier x20px x20px -45.24 Woolwich Ferry (Links A406 and A205 ) -48.55 Barking Creek/River Roding -59.25 River Darent / Dartford Creek -61.96 Dartford Tunnel (A282 (N)) -62.04 Queen Elizabeth II Bridge (A282 (S))(54.1 m) -64.76 Channel Tunnel Rail Link -69.66 Tilbury Docks -87.72 Holehaven Creek -99.42 Southend Pier, Southend-on-Sea -103.9 River Medway and Sheerness Docks -110.6 Foulness Pt/Warden Pt(PLA limit) Thames Estuary leading into the North Sea Note Distances are in kilometres. Waterway distances are shown, not footpath distances. When using imperial units, it is normal to use statute miles (1609 m) upstream of Teddington and sea miles (1853.3 m/6080 ft) downstream from Teddington.

The River Thames (ⁱ/ˈtɛmz/ TEMZ) flows through southern England. It is the longest river entirely in England and the second longest in the United Kingdom. While it is best known because its lower reaches flow through central London, the river flows alongside several other towns and cities, including Oxford, Reading, Henley-on-Thames, Windsor, Kingston upon Thames and Richmond.

The river gives its name to several geographical and political entities including the Thames Valley, a region of England around the river between Oxford and west London, the Thames Gateway, the area centred on the tidal Thames, and the Thames Estuary to the east of London. The tidal section of the river is covered in more detail under Tideway.

Summary[link]

With a total length of 346 km (215 mi), the Thames is the longest river entirely in England and the second longest in the United Kingdom. It rises at Thames Head in Gloucestershire, and flows into the North Sea at the Thames Estuary. It has a special significance in flowing through London, the capital of the United Kingdom, although London only includes a short part of its course. The river is tidal in London with a rise and fall of 7 metres (23 ft); tides reaching up to Teddington Lock. The catchment area covers a large part of South Eastern and Western England and the river is fed by over 20 tributaries. The river contains over 80 islands, and having both seawater and freshwater stretches, it supports a variety of wildlife.

The river has supported human activity from its source to its mouth for thousands of years providing habitation, water power, food and drink. It has also acted as a major highway through the Port of London for international trade, internally along its length and by its connection to the British canal system. The river’s strategic position has seen it at the centre of many events and fashions in British history, earning it a description by John Burns as “Liquid History”. It has been a physical and political boundary over the centuries and generated a range of river crossings. More recently, the river has become a major leisure area supporting tourism and pleasure outings as well as the sports of rowing, sailing, skiffing, kayaking, and punting. The river has had a special appeal to writers, artists, musicians and film-makers and is well-represented in the arts. It is still the subject of various debates about its course, nomenclature and history.

Etymology[link]

The Thames, from Middle English Temese, is derived from the Celtic name for the river, Tamesas (from *tamēssa),^[1] recorded in Latin as Tamesis and yielding modern Welsh Tafwys "Thames". The name probably meant "dark" and can be compared to other cognates such as Sanskrit tamas, Irish teimheal and Welsh tywyll "darkness" (Proto-Celtic *temeslos) and Middle Irish teimen "dark grey",^[1] though Richard Coates^[2] mentions other theories: Kenneth Jackson's^[3] that it is non Indo-European (and of unknown meaning), and Peter Kitson's^[4] that it is IE but pre-Celtic, and has a name indicating muddiness from a root *tã-, 'melt'.

Statue of Old Father Thames by Raffaelle Monti at St John's Lock

Note also other river names such as Teme, Tavy, Teviot, Teifi (cf Tafwys).

The river's name has always been pronounced with a simple t /t/; the Middle English spelling was typically Temese and Celtic Tamesis. The th spelling lends an air of Greek to the name and was added during the Renaissance, possibly to reflect or support a claim that the name was derived from River Thyamis in the Epirus region of Greece, whence early Celtic tribes were erroneously thought to have migrated.

Indirect evidence for the antiquity of the name 'Thames' is provided by a Roman potsherd found at Oxford, bearing the inscription Tamesubugus fecit (Tamesubugus made this). It is believed that Tamesubugus' name was derived from that of the river.^[5]

The Thames through Oxford is sometimes given the name the River Isis. Historically, and especially in Victorian times, gazetteers and cartographers insisted that the entire river was correctly named the River Isis from its source down to Dorchester-on-Thames, and that only from this point, where the river meets the River Thame and becomes the "Thame-isis" (supposedly subsequently abbreviated to Thames) should it be so called. Ordnance Survey maps still label the Thames as "River Thames or Isis" down to Dorchester. However since the early 20th century this distinction has been lost in common usage even in Oxford, and some historians suggest the name Isis—although possibly named after the Egyptian goddess of that name—is nothing more than a contraction of Tamesis, the Latin (or pre-Roman Celtic) name for the Thames.

Richard Coates suggests that while the river was as a whole called the Thames, part of it, where it was too wide to ford, was called *(p)lowonida. This gave the name to a settlement on its banks, which became known as Londinium, from the Indo-European roots *pleu- "flow" and *-nedi "river" meaning something like the flowing river or the wide flowing unfordable river.^[2]

Another theory of the origin of the name was published in 2009.^[6] Many ancient watery words and river names begin with a vowel, especially A. Examples include Latin amnis (big stream) and aqua, rivers Avon, Amber, Amstel, etc. Among those many rivers is the one variously called Ems (German), Emme (Switzerland), Eems, Ames (Dutch) or Amnis (Latin). The latter rivers are characterised by a big estuary or water body. From around its mouth people migrated up the Thames estuary, as early Anglo-Saxon settlers. People also left that area in the period of sea level rise before 100 BC and known as the Dunkirk 1B transgression, about when Belgae arrived in Britain according to Julius Caesar. In their region of origin they would have spoken a Germanic language, in which a locative preposition 'te', ancestral to English "at", could have supplied an initial T to 'eems' creating Temse or Temese. If so, Thames originally meant ‘at the place where the estuary begins’ and would originally not refer to the river itself but to the place where people settled (actually: London) just upstream of the dangerous tidal zone. There, travellers could be ferried to the other side. Therefore some travellers began to speak about the 'Tems' ("at the eems") as a specific (ferry-) section of the river, extending later the name to the whole river.

Tamese was referred to as a place, not a river in the Ravenna Cosmography.

For merchant seamen, the Thames has long been just 'the London River'. Londoners often refer to it simply as 'the river', in expressions such as 'south of the river'.^[7]

Physical and natural aspects[link]

Course of the river[link]

The marker stone at the official source of the River Thames near Kemble

River Thames Flood Barrier.

The Thames passes by some of the sights of London, including the Houses of Parliament and the London Eye.

The usually quoted source of the Thames is at Thames Head (at grid reference ST980994). This is about 1200 m (three quarters of a mile)^[8] north of the Kemble parish church in southern Gloucestershire, near the town of Cirencester, in the Cotswolds.^[9] Seven Springs near Cheltenham, where the river Churn rises, is also sometimes quoted as the Thames' source,^[10] as this location is furthest from the mouth, and adds some 14 miles (23 km) to the length. The springs at Seven Springs also flow throughout the year, while those at Thames Head are only seasonal. The Thames is the longest river entirely in England, but the River Severn, which is partly in Wales, is the longest river in the United Kingdom. However, as the Churn, sourced at Seven Springs is 14 miles (23 km) longer than the Thames (from its traditional source at Thames head), its length 229 miles (369 km) is greater than the Severn’s length 220 miles (350 km). Thus, the Churn/Thames river may be regarded as the longest natural river flow in the United Kingdom.

The Thames flows through or alongside Ashton Keynes, Cricklade, Lechlade, Oxford, Abingdon, Wallingford, Goring-on-Thames, Reading, Henley-on-Thames, Marlow, Maidenhead, Windsor, Eton, Staines-upon-Thames, Sunbury, Weybridge, Walton-on-Thames and Thames Ditton before entering the Greater London area. The present course is the result of several minor redirections of the main channel around Oxford, Abingdon and Maidenhead and more recently the creation of specific cuts to ease navigation.

From the outskirts of Greater London, the river passes Hampton Court, Surbiton, Kingston, Teddington, Twickenham, Richmond (with a famous view of the Thames from Richmond Hill), Syon House and Kew before flowing through central London. In central London, the river forms one of the principal axes of the city, from the Palace of Westminster to the Tower of London and was the southern boundary of the medieval city, with Southwark on the opposite bank.

Past central London, the river passes between Greenwich and the Isle of Dogs, before flowing through the Thames Barrier, which protects central London from flooding by storm surges. Below the barrier, the river passes Dagenham, Dartford, Tilbury and Gravesend before entering the Thames Estuary near Southend-on-Sea.

Catchment area and discharge[link]

The Thames River Basin District, including the Medway catchment, covers an area of 16,133 square kilometres (6,229 sq mi).^[11] The river basin includes both rural and heavily urbanised areas in the east and northern parts while the western parts of the catchment are predominantly rural. The area is among the driest in the United Kingdom. Water resources consist of ground-water from aquifers and water taken from the Thames and its tributaries, much of it stored in large bank-side reservoirs. The Thames itself provides two thirds of London’s drinking water while groundwater supplies about 40 per cent of public water supplies in the total catchment area. Groundwater is an important water source, especially in the drier months, so maintaining its quality and quantity is extremely important. Groundwater is vulnerable to surface pollution, especially in highly urbanised areas.^[11]

The non-tidal section[link]

The Jubilee River at Slough Weir.

Brooks, canals and rivers, within an area of 9,950 square kilometres (3,842 sq mi),^[12] combine to form 38 main tributaries feeding the Thames between its source and Teddington Lock, the usual tidal limit. However, high spring tides can raise the head water level in the reach above Teddington and can occasionally reverse the river flow for a short time. In these circumstances, tidal effects can be observed upstream as far as Molesey Weir^[13] which is near Hampton Court Palace. Before Teddington Lock was built in 1810–12, the river was tidal as far as Staines. The tributaries of the River Thames include the rivers Churn, Leach, Cole, Ray, Coln, Windrush, Evenlode, Cherwell, Ock, Thame, Pang, Kennet, Loddon, Colne, Wey and Mole. In addition there are many backwaters and distributaries and some man-made channels such as the Longford River.

An artificial secondary channel to the Thames, the Jubilee River, was built between Maidenhead and Windsor for flood relief and completed in 2002^[14][15]

The non-tidal section of the river is managed by the Environment Agency which is responsible for both managing the flow of water to control flooding, and providing for navigation. The volume and speed of water down the river is managed by adjusting the gates at each of the weirs and at high water levels are usually dissipated over flood plains adjacent to the river. Occasionally flooding is unavoidable, and the Agency issues Flood Warnings. During heavy rainfall the Thames occasionally receives raw sewage discharge due to sanitary sewer overflow.

The tidal section[link]

London Stone at Staines, built in 1285 marked the tidal limit of the Thames and the City of London's jurisdiction.

The lower course of the Thames in 1840.

Below Teddington Lock (about 55 miles / 89 kilometres upstream of the Thames Estuary) the river is subject to tidal activity from the North Sea. Before the lock was installed the river was tidal as far as Staines, about 16 miles (26 km) upstream.^[16] London, capital of Roman Britain, was established on two hills, now known as Cornhill and Ludgate Hill. These provided a firm base for a trading centre at the lowest possible point on the Thames.^[17] A river crossing was built at the site of London Bridge. London Bridge is now used as the basis for published tide tables giving the times of high tide. High tide reaches Putney about 30 minutes later than London Bridge, and Teddington about an hour later. The tidal stretch of the river is known as "the Tideway". Tide tables are published by the Port of London Authority and are available online. Times of high and low tides are also broadcast on Twitter.

The principal tributaries of the River Thames on the Tideway include the rivers Brent, Wandle, Effra, Westbourne, Fleet, Ravensbourne (the final part of which is called Deptford Creek), Lea, Roding, Darent and Ingrebourne. At London, the water is slightly brackish with sea salt, being a mix of sea and fresh water.

This part of the river is managed by the Port of London Authority. The flood threat here comes from high tides and strong winds from the North Sea, and the Thames Barrier was built in the 1980s to protect London from this risk.

Islands[link]

Temple Island – the start of the Henley Royal Regatta course.

The River Thames contains over 80 islands ranging from the large estuarial marshlands of the Isle of Sheppey, Isle of Grain and Canvey Island to small tree-covered islets like Rose Isle in Oxfordshire and Headpile Eyot in Berkshire. They run all the way from the Isle of Sheppey in Kent to Fiddler's Island in Oxfordshire. Some of the largest inland islands, for example Formosa Island near Cookham and Andersey Island at Abingdon, were created naturally when the course of the river divided into separate streams. In the Oxford area the river splits into several streams across the floodplain (Seacourt Stream, Castle Mill Stream, Bulstake Stream and others), creating several islands (Fiddler's Island, Osney and others). Desborough Island, Ham Island at Old Windsor and Penton Hook Island were artificially created by lock cuts and navigation channels. Chiswick Eyot is a familiar landmark on the Boat Race course, while Glover's Island forms the centrepiece of the spectacular view from Richmond Hill. Islands with a historical interest are Magna Carta Island at Runnymede, Fry's Island at Reading and Pharaoh's Island near Shepperton. In more recent times Platts Eyot at Hampton was the place where MTBs were built, Tagg's Island near Molesey was associated with the impresario Fred Karno, and Eel Pie Island at Twickenham was the birthplace of the South East’s R&B music scene.

Westminster Abbey and the Palace of Westminster (commonly known today as the Houses of Parliament) were built on Thorney Island which used to be an eyot.

Geological and topographic history[link]

Goring Gap, where the Thames broke through the Chilterns, seen from Lardon Chase.

European LGM refuges, 20,000 years ago. The Thames was a minor river that joined the Rhine, in the southern North Sea basin at this time.

  Solutrean and Proto Solutrean Cultures

  Epi Gravettian Culture

.

Geological map of the London Basin; the London Clay is marked in dark brown.

Lake in Chiswick House grounds fed by the Bollo Brook.^[18]

The confluence of Rivers Thames and Brent. The motorised barge is heading up the River Brent. From this point as far as Hanwell the Brent has been canalised and shares its course with the main line of the Grand Union Canal. From Hanwell the Brent can be traced to various sources in the Barnet area.

The River Thames can first be identified as a discrete drainage line as early as 58 million years ago, in the Thanetian stage of the late Palaeocene epoch.^[19] Until around 500,000 years ago, the Thames flowed on its existing course through what is now Oxfordshire, before turning to the north east through Hertfordshire and East Anglia and reaching the North Sea near Ipswich. At this time the river system headwaters lay in the English West Midlands and may, at times, have received drainage from the North Wales Berwyn Mountains. Streams and rivers like the River Brent, Colne Brook and Bollo Brook either flowed into the then river Thames or went out to sea on the course of the present-day river Thames.

In the most extreme Ice Age of the Pleistocene, the Anglian about 450,000 years ago, the ice sheet reached its furthest extent south, Hornchurch in north-east London.^[20] It dammed the river in Hertfordshire, causing large ice lakes which eventually burst their banks and caused the river to be diverted onto its present course through London. Progressively, the channel was pushed south to form the St Albans depression by the repeated advances of the ice sheet. This created a new river course through Berkshire and on into London, after which the river rejoined its original course in southern Essex, near the present River Blackwater estuary. Here it entered a substantial freshwater lake in the southern North Sea basin. The overspill of this lake caused the formation of the Dover Straits or Pas-de-Calais gap between Britain and France. Subsequent development led to the continuation of the course which the river follows at the present day.^[21]

Most of the bedrock of the Vale of Aylesbury is largely made up of clay and chalk that was formed at the end of the ice age and at one time was under the Proto-Thames. Also at this time the vast underground reserves of water that make the water table higher than average in the Vale of Aylesbury were created.

The last advance from that Scandinavian ice flow to have reached this far south covered much of NW Middlesex and finally forced the Proto-Thames to take roughly its present course. At the height of the last ice age around 10,000 BCE, Britain was connected to mainland Europe by a large expanse of land known as Doggerland in the southern North Sea basin. At this time, the Thames' course did not continue to Doggerland, but flowed southwards from the eastern Essex coast where it met the Rhine, the Meuse and the Scheldt^[21] flowing from what are now the Netherlands and Belgium. These rivers formed a single river—the Channel River (Fleuve Manche)—that passed through the Dover Strait and drained into the Atlantic Ocean in the western English Channel.

The ice sheet which stopped around present day Finchley, deposited Boulder clay to form Dollis Hill and Hanger Hill. Its torrent of meltwater gushed through the Finchley Gap and south towards the new course of the Thames, and proceeded to carve out the Brent Valley in the process.^[22] Upon the valley sides there can be seen other terraces of brickearth; laid over and sometimes interlayered with the clays. These deposits were brought in by the winds during the periglacial periods, suggesting that wide flat marshes were then part of the landscape, which the new river Brent proceeded to cut down. The steepness of the valley sides is witness to the very much lower mean sea levels caused by the glaciation locking up so much water upon the land masses, thus causing the river water to flow rapidly seaward and so erode its bed quickly downwards.

The original land surface was around 110 to 130 metres (350 to 400 ft) above the current sea level. The surface had sandy deposits from an ancient sea, laid over sedimentary clay (this is the Blue London Clay). All the erosion down from this higher land surface and sorting action by these changes of water flow and direction formed what is known as the Thames River Gravel Terraces. Since Roman times and perhaps earlier, however, the isostatic rebound from the weight of previous ice sheets, and its interplay with the eustatic change in sea level, has resulted in the old valley of river Brent, together with that of the Thames, silting up again. Thus along much of the Brent's present-day course one can make out the water meadows of rich alluvium, which is augmented by frequent floods.

After taking its present-day course, much of the banks of the Thames Estuary and the Thames Valley in London was partly covered in marshland, as was the adjoining Lower Lea Valley. The streams and rivers like the River Lea, Tyburn Brook and Bollo Brook drained into the river, while some islands like Thorney Island formed over the ages. The northern tip of the ancient parish of Lambeth, for example, was a marshland known as Lambeth Marshe, but it was drained in the 18th century and is remembered in the Lower Marsh street name. Sometime after the opening of Waterloo railway station in 1848 the locality around the station and Lower Marsh became known as Waterloo. Lower Marsh is a street in the Waterloo neighbourhood of London. It is the location of Lower Marsh Market.^[23]