{{Short description|Artificial island in the Wash}} {{Use dmy dates|date=April 2025}} {{Use British English|date=April 2025}} {{Infobox park | name = Outer Trial Bank | image = Outer Trial Bank (aerial).jpg | image_size = 220 | image_alt = | image_caption = | type = Nature reserve | location = The Wash, East Anglia, England | coordinates = {{coord|52.8418|0.2431|type:landmark|display=inline,title}} | area = {{convert|4.265|ha|acre}} | created = | operator = | visitation_num = | status = }}
The '''Outer Trial Bank''' is a circular artificial island in the Wash, East Anglia, England. It is one of two artificial islands constructed during the 1970s for a proposed UK governmental water resources scheme.<ref name="looknorth">{{cite news|url=https://news.bbc.co.uk/2/hi/uk_news/england/7659304.stm|title=Investigation of Wash Island|date=8 October 2008|first=Matt|last=Richards|work=BBC Look North|publisher=BBC|access-date=1 March 2010}}</ref>
== History ==
In 1972, the British government undertook a study to assess the feasibility of building a tidal barrage across half of the Wash. The idea was to capture the freshwater from the River Witham, River Welland, River Nene and Great Ouse, the four main rivers which flow into the Wash, in order to build a freshwater reservoir.<ref name="looknorth" /> The study also intended to establish potential improvements to the navigation of sea locks, provide recreational facilities and develop an area of land for a power station.<ref name="washproject">{{cite web|url=http://www.washestuary.org.uk/details.cfm?id=117 |title=The Past |work=The Wash Project |publisher=The Wash Estuary Strategy Group |accessdate=1 March 2010 |url-status=dead |archiveurl=https://web.archive.org/web/20061011192316/http://www.washestuary.org.uk/details.cfm?id=117 |archivedate=11 October 2006}}</ref>
=== Construction of the banks === As part of the test, the approval to build an artificial island {{convert|2|mi|km}} off the Lincolnshire coast was given in November 1974.<ref name="BNCOLD" /><ref name="bbclincs" /> Building work began in February 1975.<ref name="BNCOLD" /> The bank (known locally as "the doughnut" due to its biconcave shape<ref name="bbclincs" />) was constructed of a sand fill protected by limestone rubble.<ref name="BNCOLD" /> Measuring {{convert|250|m|ft}} in diameter, the island contained a small reservoir measuring {{convert|1|ha|acre}} in the centre.
A smaller and cruder trial bank is connected by a causeway on Terrington Marsh, Norfolk ({{nowrap|{{coord|52|49|7.05|N|0|17|15.28|E|scale:5000|display=inline}}}}). It was constructed prior to the larger offshore version.<ref name="BNCOLD">{{cite journal|year=1975|title=Wash Water storage scheme|journal=News and Views|publisher=British National Committee on Large Dams|issue=16|pages=15–16|url=http://www.britishdams.org/publications/News%20and%20Views/No16,%201975,%20News%20&%20Views.pdf|accessdate=2 March 2010}}</ref>
=== Conclusions === The study, which was published in 1976 as ''"The Wash storage scheme"'',<ref name="natarchives">{{cite web|url=http://www.nationalarchives.gov.uk/catalogue/displaycataloguedetails.asp?CATID=451605&CATLN=6&Highlight=&FullDetails=True|title=The Wash storage scheme: report on the feasibility study|year=1976|work=Central Water Planning Unit|publisher=The National Archives|accessdate=1 March 2010}}</ref> found that the trial alone proved financially unfeasible (costing £3 million),<ref name="bbclincs" /> and that the freshwater was too close to the tidal estuary to ensure low salinity and minimal silt levels.<ref name="looknorth" /> The trial was soon abandoned and the plans for the scheme permanently shelved.<ref name="bbclincs">{{cite web|url=https://www.bbc.co.uk/lincolnshire/content/articles/2008/10/08/abandoned_wash_feature.shtml|title=Abandoned: What's in the Wash?|date=15 October 2008|publisher=BBC Lincolnshire|accessdate=1 March 2010}}</ref>
== Present use == thumb|Outer Trial Bank at sunset from West Bank, Sutton BridgeThe outer bank is a nesting ground for seabirds within the national nature reserve of the Wash. In 2008, an estimated 3,000 pairs of birds nested on the island.<ref name="looknorth" />
== See also == *Centre Port, a plan for a tidal barrage across The Wash
== References == {{reflist}} {{Commons category|The Outer Trial Bank}}
Category:Artificial islands of England Category:Landforms of Lincolnshire Category:Landforms of Norfolk Category:Islands of England