The Thames Barrier is a flood control structure on the River Thames, constructed between 1974 and 1984 at Woolwich Reach, London. It is the world's second largest movable flood barrier (the largest is the Oosterscheldekering in The Netherlands). Flooding in Amphoe Sena, Ayutthaya Province, Thailand. ... This article is about the River Thames in southern England. ... , Woolwich town hall dates from when this was a borough in its own right. ... This article is about the capital of England and the United Kingdom. ... Tokyo floodgates to protect from typhoon surges. ... The Oosterscheldekering (Eastern Scheldt storm surge barrier), between the islands Schouwen-Duiveland and Noord-Beveland, is the largest of the 13 ambitious Delta works series of dams, designed to protect a large part of the Netherlands from flooding. ... Motto: Je Maintiendrai (Dutch: Ik zal handhaven, English: I Shall Uphold) Anthem: Wilhelmus van Nassouwe Capital Amsterdam1 Largest city Amsterdam Official language(s) Dutch2 Government Parliamentary democracy Constitutional monarchy  - Queen Beatrix  - Prime minister Jan Peter Balkenende Independence Eighty Years War   - Declared July 26, 1581   - Recognised January 30, 1648 (by Spain...

Located downstream of central London, the barrier's purpose is to prevent London being flooded by an exceptionally high tide moving up from the sea, exacerbated by a storm surge. It only needs to be raised for the duration of the high tide, at low tide it can be opened to release water flowing down the Thames which backs up behind it. This article is about tides in the Earths oceans. ... ...

River Thames Flood Barrier

The gate in the middle of this view has been raised to the maintenance position; a barge can be seen in the foreground.

Image File history File links Download high resolution version (1600x1200, 620 KB) File links The following pages link to this file: Thames Barrier ... Image File history File links Download high resolution version (1600x1200, 620 KB) File links The following pages link to this file: Thames Barrier ... ImageMetadata File history File links Download high resolution version (1600x1200, 342 KB) The Thames Barrier. ... ImageMetadata File history File links Download high resolution version (1600x1200, 342 KB) The Thames Barrier. ...

Description

Built across a 523 metre wide stretch of the river, the barrier divides the river into four 61m and two 31m navigable spans and four smaller non-navigable channels between nine concrete piers and two abutments. The flood gates across the openings are circular segments in cross section, and they operate by rotating, raised by hydraulics from a horizontal cill on the riverbed to form a barrier of steel and concrete. They can rotate further to allow "underspill" to allow operators to control upstream levels and a complete 180 degree rotation for maintenance. All the gates are hollow and made of steel up to 40mm thick. The gates fill with water when submerged and empty as they emerge from the river. The four large central gates are 61 metres long, 10.5 metres high (above local ground level) and weigh 3,500 tonnes; the outer two gates are 31.5 metres. Additionally, four radial gates by the riverbanks can be lowered. These gate openings, unlike the main six, are non-navigable. The gates are normally left open to allow ships to pass through, but can be rotated and closed to stop water travelling up the Thames through London. This article is about the unit of length. ... In geometry, a circular segment (also circle segment) is an area of a circle informally defined as an area which is cut off from the rest of the circle by a secant or a chord. ... A tonne or metric ton (symbol t), sometimes referred to as a metric tonne, is a measurement of mass equal to 1,000 kilograms. ...

Before 1990, the number of barrier closures was one to two per year on average. Since 1990, the number of barrier closures has increased to an average of about four per year.^[1] In 2003 the Barrier was closed on 14 consecutive tides.

Design and construction

The concept of the rotating gates was devised by Charles Draper. The barrier was designed by Rendel, Palmer and Tritton for the Greater London Council and tested at HR Wallingford. The site at Woolwich was chosen because of the relative straightness of the banks, and because the underlying river chalk was strong enough to support the barrier. Work began at the barrier site in 1974 and construction, which had been undertaken by a Costain/Hollandsche Beton Maatschappij/Tarmac Construction consortium, was largely complete by 1982. In addition to the barrier itself the flood defences for 11 miles down river were raised and strengthened. The barrier was officially opened on May 8, 1984. Total construction cost was around £534 m (£1.3 billion at 2001 prices) with an additional £100 m for river defences. The barrier was originally designed to protect London against a flood level with a return period of 1000 years in the year 2030 after which the protection would decrease but be within acceptable limits. This defence level included long term changes in sea and land levels as understood at that time (c. 1970). Since then sea level rise due to global warming has been identified. Based on current estimates ^[2]the barrier will be able to cope with projected sea level rises until around 2030–2050 and is expected to serve its full term. Since 1982 the barrier has been raised over 100^[3] times; further, it is raised every month for testing. The barrier was originally commissioned by the Greater London Council under the guidance of Ray Horner. After the 1986 abolition of the GLC it was operated successively by Thames Water Authority and then the National Rivers Authority until April 1996 when it passed to the Environment Agency. Year 1974 (MCMLXXIV) was a common year starting on Tuesday (link will display full calendar) of the 1974 Gregorian calendar. ... Costain Group plc is a British construction and civil engineering company headquartered in Maidenhead. ... You may be looking for Carillon Carillion plc (LSE: CLLN) is a British based construction services business headquartered in Wolverhampton. ... Year 1982 (MCMLXXXII) was a common year starting on Friday (link displays the 1982 Gregorian calendar). ... is the 128th day of the year (129th in leap years) in the Gregorian calendar. ... This article is about the year. ... A return period also known as a recurrence interval is an estimate of the liklihood of a flood or river discharge flow of a certain size. ... 2030 (MMXXX) will be a common year starting on Tuesday of the Gregorian calendar. ... 2050 (MML) will be a common year starting on Saturday of the Gregorian calendar. ... Arms of the Greater London Council The Greater London Council (GLC) was the top-tier local government administrative body for Greater London from 1965 to 1986. ... Thames Water, known originally as the Thames Water Authority and after privatization as Thames Water Utilities Limited, is the utility responsible for water supply and waste water treatment in parts of Greater London, Surrey, Wiltshire, and the Thames Valley in the United Kingdom. ... -1... Year 1996 (MCMXCVI) was a leap year starting on Monday (link will display full 1996 Gregorian calendar). ... (see also the List of environmental organizations) The Environment Agency (Welsh: Asiantaeth yr Amgylchedd) of England and Wales was created by the Environment Act 1995, along with the Scottish Environment Protection Agency. ...

In 2005, a suggestion that it might become necessary to supersede the Thames Barrier with a much more ambitious 16 km (10 mi) long barrier across the Thames Estuary from Sheerness in Kent to Southend in Essex was made public. , Sheerness is a town located beside the mouth of the River Medway on the northwest corner of the Isle of Sheppey in north Kent, England. ... For other uses, see Kent (disambiguation). ... Southend-on-Sea is a resort town in Essex, England. ... For other meanings of Essex, see Essex (disambiguation). ...

Previous flooding

One of the gates in Underspill(Mar 2007)

A breach at Erith after the 1953 flood

London is quite vulnerable to flooding. A storm surge generated by low pressure in the Atlantic Ocean sometimes tracks eastwards past the north of Scotland and may then be driven into the shallow waters of the North Sea. The storm surge is funnelled down the North Sea which narrows towards the English Channel and the Thames Estuary. If the storm surge coincides with a spring tide then dangerously high water levels can occur in the Thames Estuary. This situation combined with downstream flows in the Thames provides the triggers for Flood defence operations. Image File history File linksMetadata Size of this preview: 800 × 532 pixelsFull resolution (3008 × 2000 pixel, file size: 2. ... Image File history File linksMetadata Size of this preview: 800 × 532 pixelsFull resolution (3008 × 2000 pixel, file size: 2. ... Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... ... The North Sea is a sea of the Atlantic Ocean, located between the coasts of Norway and Denmark in the east, the coast of the British Isles in the west, and the German, Dutch, Belgian and French coasts in the south. ... For the Thoroughbred racehorse of the same name, see English Channel (horse). ... Several places exist with the name Thames, and the word is also used as part of several brand and company names Most famous is the River Thames in England, on which the city of London stands Other Thames Rivers There is a Thames River in Canada There is a Thames... This article is about tides in the Earths oceans. ...

According to Gilbert & Horner on 7th December 1663 Samuel Pepys recorded in his diary 'There was last night the greatest tide that ever was remembered in England to have been in this river all Whitehall having been drowned'. In 1236 the river is reported as overflowing 'and in the great Palace of Westminster men did row with wherries in the midst of the hall'. (Gilbert & Horner - 1984). Fourteen people died in the 1928 Thames flood, and after 307 people died in the UK in the North Sea Flood of 1953 the issue gained new prominence. Samuel Pepys, FRS (23 February 1633 – 26 May 1703) was an English naval administrator and Member of Parliament, who is now most famous for his diary. ... The 1928 Thames flood was a disastrous flood of the River Thames that affected much of riverside London, England, on 7 January 1928, as well as places further downriver. ... The North Sea flood of 1953 and the associated storm combined to create a major natural disaster which affected the coastlines of the Netherlands and England on the night of 31 January 1953 – 1 February 1953. ...

The threat has increased over time due to the slow but continuous rise in high water level over the centuries (20 cm / 100 years) and the slow "tilting" of Britain (up in the North and down in the South) caused by post-glacial rebound. Changes in the elevation of Lake Superior due to glaciation and post-glacial rebound Post-glacial rebound (sometimes called continental rebound, isostatic rebound or isostatic adjustment) is the rise of land masses that were depressed by the huge weight of ice sheets during the last ice age, through a process...

Early proposals for a flood control system were stymied by the need for a large opening in the barrier to allow for vessels from London Docks to pass through. When containerization came in and a new port was opened at Tilbury, a smaller barrier became feasible with each of the four main navigation spans being the same width as the opening of Tower Bridge. Shipping containers at a terminal in Port Elizabeth, New Jersey. ... Tilbury is located on the north bank of the River Thames, in the borough of Thurrock in England, at the point where the river suddenly narrows to about 800 yards/740 metres in width. ... For the bridge of the same name in California, see Tower Bridge (California). ...

An incident which had the potential to be catastrophic for London occurred on 27 October 1997. The dredger, MV Sand Kite, sailing in thick fog, collided with one of the Thames Barrier's piers. As the ship started to sink she dumped her 3,300 tonne load of aggregate, finally sinking by the bow on top of one of the barrier's gates where she sat for several days. Initially the gate could not be closed as it was covered in a thick layer of gravel. A longer term problem was the premature loss of paint on the flat side of the gate caused by abrasion. One estimate of the cost of flooding damage, had it occurred, was around £13 billion.^[4] Eventually the vessel was refloated in mid-November 1997. is the 300th day of the year (301st in leap years) in the Gregorian calendar. ... For the band, see 1997 (band). ... ...

Flood Defence Operations

A Thames Barrier flood defence closure is triggered when a combination of high tides forecast in the North Sea and high river flows at the tidal limit at Teddington weir indicate that water levels would exceed 4.87 m in central London. Forecast sea levels at the mouth of the Thames Estuary are generated by Met Office computers and also by models run on the Thames Barrier's own forecasting and telemetry computer systems. About 9 hours before the high tide reaches the barrier a flood defence closure begins with messages to stop river traffic, close subsidiary gates and alert other river users. As well as the Thames Barrier, the smaller gates along the Thames Tideway include Barking Barrier, King George V Lock gate, Dartford Barrier and gates at Tilbury Docks and Canvey Island. Once river navigation has been stopped and all subsidiary gates closed, then the Thames Barrier itself can be closed. The smaller gates are closed first, then the main navigable spans in succession. The gates remain closed until the tide downstream of the barrier falls to the same level as the water level upstream. , Teddington is an area of London, England on the north bank of the River Thames, between Hampton Wick and Twickenham. ... The bridge and weir mechanism at Sturminster Newton on the River Stour, Dorset. ... The new building on the edge of Exeter The Met Office (originally an abbreviation for Meteorological Office, but now the official name in itself), which has its headquarters at Exeter in Devon, is the United Kingdoms national weather service. ... Look up forecast in Wiktionary, the free dictionary. ... Telemetry is a technology that allows the remote measurement and reporting of information of interest to the system designer or operator. ... This article is about tides in the Earths oceans. ...

After periods of heavy rain west of London, floodwater can also flow down the Thames upstream from London. Because the river is tidal from Teddington weir all the way through London, this is only a problem at high tide, which prevents the floodwater from escaping out to sea. From Teddington the river is opening out into its estuary, and at low tide it can take much greater flow rates the further one goes downstream. In periods when the river is in flood upstream, if the gates are closed shortly after low tide, a huge empty volume is created behind the barrier which can act as a reservoir to hold the floodwater coming over Teddington weir. Most river floods will not fill this volume in the few hours of the high tide cycle during which the barrier needs to be closed. If the barrier was not there, the high tide would fill up this volume instead, and the floodwater could then spill over the river banks in London.

Popular culture

• In GLC: The Carnage Continues... Ken Livingstone is thrown off the barrier on the orders of the ex-Lord Mayor of London, who wants his job back.
• In Series 5 Episode 10 of the BBC drama Spooks, environmental terrorists take control of the barrier in order to let London flood during a spring tide.
• In the Doctor Who episode The Runaway Bride, the secret agency Torchwood is revealed to have built a secret base beneath the Thames Barrier.
• In the graphic novel V for Vendetta, Evey Hammond recounts to V how the Thames Barrier had burst during the limited nuclear war, flooding London.
• In the Flood (film) which aired on television in 2007. The Thames Barrier was used to try and prevent the flooding of London; however, it was unsuccessful.

GLC: The Carnage Continues was an episode of The Comic Strip Presents. ... Due to air in the UK 9pm 14th November 2006. ... For the music band, see The Spooks. ... The tide is the regular rising and falling of the oceans surface caused by changes in gravitational forces external to the Earth. ... For other uses, see Doctor Who (disambiguation). ... The Runaway Bride is a special episode of the long running British science fiction television series Doctor Who, starring David Tennant as the Tenth Doctor. ... The Torchwood Institute is a fictional organisation from the British science fiction television series Doctor Who and its spin-off series, Torchwood. ... This article is about the comic book series. ... Nuclear War is a card game designed by Douglas Malewicki, and originally published in 1966. ... This article is about the capital of England and the United Kingdom. ... Flood is a disaster film, with a planned release in August 2007 and directed by Tony Mitchell. ...

Gallery

The Thames Barrier, Gate F in maintenance ImageMetadata File history File links Download high resolution version (1400x1023, 577 KB) Thames Barrier File links The following pages link to this file: Thames Barrier ...	The Thames Barrier ImageMetadata File history File links Download high resolution version (1800x1292, 633 KB) Overall view of a Thames Barrier pier. ...	The Thames Barrier, Pier 6 ImageMetadata File history File links Download high resolution version (1800x1342, 649 KB) File links The following pages link to this file: Thames Barrier ...	Gate in Maintenance, from a distance ImageMetadata File history File links Download high resolution version (1800x1157, 570 KB) File links The following pages link to this file: Thames Barrier ...
Gate in Maintenance, medium view ImageMetadata File history File links Download high resolution version (1800x1212, 597 KB) A distant view of workers roped to a barrier. ...	Gate in Maintenance, close up ImageMetadata File history File links Download high resolution version (1800x1339, 662 KB) File links The following pages link to this file: Thames Barrier ...	Pier close up ImageMetadata File history File links Download high resolution version (1800x1347, 562 KB) File links The following pages link to this file: Thames Barrier ...

See also

• Thames Barrier Park
• Floodgates
• Oosterscheldekering, part of the Delta Works

Looking across the park towards the Thames Barrier The Thames Barrier Park is a 22 Acre park in Londons docklands, named after its location on the north side of the River Thames next to the Thames Barrier. ... Tokyo floodgates to protect from typhoon surges. ... The Oosterscheldekering (Eastern Scheldt storm surge barrier), between the islands Schouwen-Duiveland and Noord-Beveland, is the largest of the 13 ambitious Delta works series of dams, designed to protect a large part of the Netherlands from flooding. ... The Delta Works are a number of constructions that were built between 1950 and 1997 in the southwest of the Netherlands to protect a large area of land from the sea. ...

References

Hansard is the traditional name for the printed transcripts of parliamentary debates in the Westminster system of government. ...

Bibliography

Stuart Gilbert and Ray Horner - The Thames Barrier - Telford 1984 ISBN 0-7277-0249-1

External links

• BBC News: On The Rise, The Thames in 2100

Wikimedia Commons has media related to:

Thames Barrier

• Aerial photo of Thames Barrier. Other map and aerial photo sources.
• Thames Barrier page at the Environment Agency
• Port of London Authority for information on Navigation through the Thames Barrier
• BBC report of potential outer barrier
• Flood Londons

Coordinates: 51°29′52″N 0°02′12″E / 51.497744, 0.036679 Image File history File links Commons-logo. ... This is a list of crossings of the River Thames, downstream first, including bridges, tunnels and ferries. ... This article is about the River Thames in southern England. ... London Transport Portal The Jubilee Line is a line on the London Underground (the Tube), in England. ... Canning Town station is a major inter-modal transport interchange in East London. ... North Greenwich tube station on the Jubilee Line opened in time for the Millennium celebrations at the end of 1999 - it is adjacent to the Millennium Dome at the northern end of an area sometimes referred to as the Greenwich peninsula. ... The Woolwich foot tunnel is a tunnel crossing under the River Thames in east London from Woolwich in the London Borough of Greenwich to North Woolwich in the London Borough of Newham. ... Map of Earth showing lines of latitude (horizontally) and longitude (vertically), Eckert VI projection; large version (pdf, 1. ...