What is Thames Barrier?
{{coord|51.497744|0.036679|display=title}} [[Image:Thames Barrier London.jpg|thumb|300px|right|River Thames Flood Barrier]] [[Image:Thames Barrier 059184.jpg|thumb|300px|right|The gate in the middle of this view has been raised to the maintenance position; a barge can be seen in the foreground.]] The '''Thames Barrier''' is the world's second-largest movable [[flood]] [[wikt:barrier|barrier]], after the [[Oosterscheldekering]] in the [[Netherlands]]. It is downstream of central [[London]].<ref>Downstream = towards the sea; in this case, east of London towards the Thames [[estuary]].</ref> Its purpose is to prevent London from being flooded by exceptionally high [[tide]]s and [[storm surge]]s moving up from the [[North Sea]]. It is raised (closed) only during [[high tide]]; at [[ebb tide]] it is lowered to release the water which backs up behind it. The barrier's northern bank is in the [[London Borough of Newham]] and its southern bank is in the [[London Borough of Greenwich]]. The report of [[Hermann Bondi]] into the [[North Sea flood of 1953]] affecting parts of the [[Thames Estuary]] and parts of London was what led to the building of the barrier.<ref>{{Cite web |url=http://www.westsilvertownfoundation.org.uk/Floods1953.pdf |title=1953 floods in Canning Town, Accessed 30 December 2010 |access-date=6 September 2011 |archive-date=20 November 2008 |archive-url=https://web.archive.org/web/20081120181337/http://www.westsilvertownfoundation.org.uk/Floods1953.pdf |url-status=dead }}</ref><ref>{{cite ODNB|url=http://www.oxforddnb.com/view/10.1093/ref:odnb/9780198614128.001.0001/odnb-9780198614128-e-96022|title=Bondi, Sir Hermann (1919–2005), applied mathematician and scientific administrator|doi=10.1093/ref:odnb/96022 |isbn=978-0-19-861412-8 }}</ref> == Geography == === Geographical weather system === London is 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 S