Editing Teddington Lock (section)

==History==
===First lock, 1810===
The [[Navigation Acts|Navigation Act]] obtained in April 1771 by the Thames Navigation Commission did not allow them to build locks below [[Maidenhead Bridge]],{{sfn |Skempton |1996 |p=153}} but from 1802, several plans for locks in the First District of the Thames, stretching from Staines to Teddington, were drawn up. Stephen Leach took over the post of Clerk of Works for the First District in 1802, following the retirement of Charles Truss at the age of 82. Just before his retirement, Truss proposed locks at Molesey and Teddington, each having a weir with long tumbling bays, similar to modern practice. [[John Rennie the Elder|John Rennie]] had suggested a series of long cuts in 1794, and Truss adopted the same idea. Rennie and [[William Jessop]] again proposed four long cuts in 1805, each about {{convert|1.5|mi|km}}, but the Navigation Committee were thwarted by strong opposition from landowners.{{sfn |Skempton |1996 |p=165}}

Zacchary Allnutt, by then Surveyor for the Second and Third Districts, stretching from Staines to [[Mapledurham Lock|Mapledurham]] near Reading, suggested locks at Chertsey, Sunbury and Teddington in 1805. Rennie submitted new proposals in 1809 for nine locks between Staines and Twickenham; two would be without weirs, seven would require large weirs to be built. Finally Leach drafted plans in 1810, which he suggested were "at once practicable and expedient, the least expensive, and the most likely to pass through Parliament without opposition and yet calculated to remedy the most prominent evils complained of." An [[Act of Parliament]] was obtained by the [[City of London Corporation]] in June 1810, which authorised construction of locks and weirs at [[Chertsey Lock|Chertsey]], [[Shepperton Lock|Shepperton]], [[Sunbury Lock|Sunbury]] and Teddington. Each would be {{convert|150|by|20|ft|m}} with the associated weirs having ample capacity for flood conditions. Rennie, Leach and the Navigation Committee visited the sites in July, to finalise the positioning of the lock.{{sfn |Skempton |1996 |p=165}}  Leach then took charge of the work, which was undertaken by contractors Joseph Kimber and John Dows who also built Sunbury Lock.<ref>{{cite book |url=https://books.google.com/books?id=jeOMfpYMOtYC&pg=PA397 |title=A Biographical Dictionary of Civil Engineers in Great Britain and Ireland |editor-first=Alec W. |editor-last=Skempton |publisher=Thomas Telford, on behalf of the [[Institution of Civil Engineers]] |location=London |year=2002 |volume=1 |pages=14,397 |isbn=978-0-7277-2939-2 |oclc=223272473}}</ref><ref name="Thacker1914">{{cite book |first=Fred. S. |last=Thacker |title=The Thames Highway |url=https://archive.org/stream/thameshighwayhis00thacrich#page/206/mode/2up |year=1914 |publisher=Fred S. Thacker |location=Holborn, London |lccn=15024238 |pages=206–208}}</ref>

Work at Teddington started in September 1810, but there were delays caused by flooding in November and December, and Leach awarded the contractors an extra £500. The lock was finished and opened in June 1811, but the weir was incomplete. The cofferdam protecting the works would need to be removed as river levels rose in the winter, which would have delayed completion until the following July, and so again Leach stepped in, awarding advance payments to the contractors, which enabled them to finish on time.{{sfn |Skempton |1996 |p=166}} The lock was further upstream than the present lock complex at the point where the footbridge now crosses. It comprised three pairs of gates as stipulated in the act.<ref name="Thacker1914" /> Total cost for lock, cut, weir, ballast and ground was £22,035 10''s.'' {{frac|7|1|2}}''d.'' ({{Inflation|GBP|22035.5|1810|r=-3|fmt=eq|cursign=£}}) of which the land from [[Wilbraham Tollemache, 6th Earl of Dysart|Lord Dysart's]] estate cost £282 10''s.'' 5''d.''.<ref>{{cite web |url=https://books.google.com/books?id=1hdDAAAAcAAJ&pg=PA843 |title=Journal of the House of Commons |year=1813 |publisher=[[HMSO]] |volume=69 |page=844 |postscript=. (Appendix)}}</ref> The lock was, at first, highly unpopular with the local fishermen and bargemen. After attempts to smash it, the lock keeper was granted permission to keep "a [[blunderbuss]] with [[bayonet]] attached thereto" to ward off attacks.<ref name="Croad2003">{{cite book |last=Croad |first=Stephen |title=Liquid History: The Thames Through Time |url=https://books.google.com/books?id=wI9nAAAAMAAJ |year=2003 |publisher=Batsford |isbn=978-0-7134-8834-0 |page=27}}</ref>

===Rebuild, 1857===
By 1827 the [[timber]] lock needed considerable repair and in 1829 the weir was destroyed by an accumulation of ice. It is noted that in 1843 the lock keeper prevented a steam vessel from ascending the lock. At that time steam vessels were limited to travel as far (upstream) as Richmond. As originally built, the lock had timber sides up to normal head water level, and turf above that. The crest of the weir was {{convert|3.5|ft|m}} above low water level at Teddington, but following the removal of the piers of old [[London Bridge]] (demolished 1831) in 1832, the drop increased to {{convert|4.5|ft|m}} and increased to {{convert|6|ft|m}} when dredging of the river was carried out.{{sfn |Skempton |1996 |p=166}} At tidally lower water occasional grounding of [[barges]] took place below the bottom sill.

Consideration was given to removing the lock altogether in 1840.<ref>{{cite journal |url=https://books.google.com/books?id=kxJAAAAAYAAJ&pg=PA66 |title=Number II, The Mapledurham Scheme |journal=The Civil Engineers and Architect's Journal |date=February 1840 |volume=13 |page=66}}</ref> However, it was decided to rebuild the lock and in June 1854 proposals included providing capacity for seagoing craft with a side lock for pleasure traffic. In June 1857 the first stone of the new lock was laid at the present position, the central of the three, opened in 1858 together with the narrow [[Thames skiff|skiff]] lock,{{refn|group=n|Nicknamed among lock-keepers and lock users "the coffin"}}. The boat slide, separate, was added in 1869 and in the 1870s the weir collapsed twice causing enormous damage. After the weir had been rebuilt in 1871, sluice bays spanned around {{convert|240|ft|m}}, similar to the tumbling bays.{{refn|group=n|The terms sluice bay and tumbling bay are two types of weir structures; the first, suspended and the second, a rising or fixed barrier.}}{{sfn |Skempton |1996 |p=166}}

===Footbridges and barge lock===
The [[Teddington Lock Footbridges|footbridges]] were opened in 1889 and finally the barge lock, the largest lock on the river, was built in 1904–1905.<ref>{{cite book |first=Fred. S. |last=Thacker |title=The Thames Highway: Volume II Locks and Weirs |year=1920 |publisher=republished 1968 David & Charles |isbn=978-0-7153-4233-6 |url-access=registration |url=https://archive.org/details/thameshighway0000thac }}</ref> {{convert|7000|cuyd|m3}} of the extracted gravel was used to raise the level of [[Cross Deep Ait]], a former [[ait]] adjacent to [[Swan Island, London|Swan Island]] downstream, to protect it from flooding.<ref>{{cite web |url=http://friendsofradnorgardens.org.uk/public/index.php/plan/site/ |title=Site Description |publisher=Friends of Radnor Gardens |access-date=9 June 2015}}</ref> The footbridges are [[Listed building|Grade II listed]].<ref>{{National Heritage List for England |num=  1391392|desc=Teddington Lock Footbridges|date= 3 October 2005|access-date= 30 June 2017}}</ref>

===World War II===
In 1940 Teddington Lock was the assembly point for an enormous [[flotilla]] of small ships from the length of the River Thames to be used in the [[evacuation of Dunkirk]].

=== 21st century===
{{update|section|date=July 2020}}
Early twenty-first century renovation and improvement work in the area around the locks was undertaken as part of the Thames Landscape Strategy Teddington Gateway project.<ref>{{cite web |url=http://www.thames-landscape-strategy.org.uk/teddingtongateway/ |title=Thames Landscape Strategy Teddington Gateway project |access-date=14 November 2005 |archive-url=https://web.archive.org/web/20080724194751/http://thames-landscape-strategy.org.uk/teddingtongateway |archive-date=24 July 2008}}</ref><ref>{{cite web |url=http://www.environment-agency.gov.uk/news/144214.aspx?page=6&month=11&year=2012 |publisher=[[Environment Agency]] |title=Oldest timber lock gates on the Thames treated to a makeover |date=15 November 2012}}</ref><ref>{{Cite web |title=Teddington Lock footbridges improvement works |url=https://www.richmond.gov.uk/services/roads_and_transport/transport_planning_schemes/transport_schemes/teddington_lock |access-date=2025-05-20 |website=London Borough of Richmond upon Thames |language=en-gb}}</ref>

<!-- [[Ham Hydro]] redirects here -->
In 2009, a local community group initiated a feasibility study for exploiting Teddington's weir for electricity generation, inspired by similar community-led generation schemes; [[Torrs Hydro]] and [[Settle Hydro]]. The study was encouraging and the ''Ham Hydro'' project now proposes using three reverse-[[Archimedes' screw|Archimedean screws]] with a total output of {{convert|492|kW|hp}}.<ref>{{cite web |url=http://www.hamhydro.org/from-idea-to-reality |title=From Idea To Reality |publisher=Ham Hydro |access-date=30 June 2013}}</ref> Environmental concerns, notably those raised by anglers about the potential effect on fish populations, prompted further environmental surveys during 2012. The outcome of these considerations is awaited before the [[London Borough of Richmond upon Thames]] will determine whether planning permission is to be granted for the scheme.<ref>{{cite web |url=http://www.rivertac.org/thames-hydropower/hydropower-at-teddington-weir/ |title=Hydropower at Teddington Weir |publisher=Thames Anglers Conservancy |access-date=30 June 2013}}</ref><ref>{{cite news |url=http://www.yourlocalguardian.co.uk/news/local/richmondnews/9441054.Hydro_electric_application_submitted/ |title=Teddington weir hydro-electric application submitted |date=28 December 2011 |first=Christine |last=Fleming |newspaper=Richmond Guardian}}</ref>