Outer Trial Bank

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search

Outer Trial Bank
Outer Trial Bank (aerial).jpg
TypeNature reserve
LocationThe Wash, East Anglia, England
Coordinates52°50′30″N 0°14′35″E / 52.8418°N 0.2431°E / 52.8418; 0.2431Coordinates: 52°50′30″N 0°14′35″E / 52.8418°N 0.2431°E / 52.8418; 0.2431
Area4.265 hectares (10.54 acres)

The Outer Trial Bank is a circular artificial island in the Wash, East Anglia, England. It is one of two islands constructed during the 1970s for a governmental water resources scheme.[1]


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 to build a freshwater reservoir.[1] 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.[2]

Construction of the banks[edit]

As part of the test, the approval to build an artificial island 2 miles (3.2 km) off the Lincolnshire coast was given in November 1974.[3][4] Building work began in February 1975.[3] The bank (known locally as "the doughnut" due to its biconcave shape[4]) was constructed of a sand fill protected by limestone riprap.[3] Measuring 250 metres (820 ft) in diameter, the island contained a small reservoir measuring 1 hectare (2.5 acres) in the centre.

A smaller and cruder trial bank is connected by a causeway on Terrington Marsh, Norfolk (52°49′7.05″N 0°17′15.28″E / 52.8186250°N 0.2875778°E / 52.8186250; 0.2875778). It was constructed prior to the larger offshore version.[3]


The study, which was published in 1976 as "The Wash storage scheme",[5] found that the trial alone proved financially unfeasible (costing £3 million),[4] and that the freshwater was too close to the tidal estuary to ensure low salinity and minimal silt levels.[1] The trial was soon abandoned and the plans for the scheme shelved.[4]

Present use[edit]

The 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.[1]


  1. ^ a b c d Richards, Matt (8 October 2008). "Investigation of Wash Island". BBC Look North. BBC. Retrieved 1 March 2010.
  2. ^ "The Past". The Wash Project. The Wash Estuary Strategy Group. Archived from the original on 11 October 2006. Retrieved 1 March 2010.
  3. ^ a b c d "Wash Water storage scheme" (PDF). News and Views. British National Committee on Large Dams (16): 15–16. 1975. Retrieved 2 March 2010.
  4. ^ a b c d "Abandoned: What's in the Wash?". BBC Lincolnshire. BBC. 15 October 2008. Retrieved 1 March 2010.
  5. ^ "The Wash storage scheme: report on the feasibility study". Central Water Planning Unit. The National Archives. 1976. Retrieved 1 March 2010.