Beaufort's Dyke

Beaufort's Dyke is a natural trench between Northern Ireland and Scotland within the North Channel. The dyke is 50 km (30 miles) long, 3.5 km (2 miles) wide and 200–300 m (700–1,000 ft) deep.

Beaufort's Dyke

Geomorphology

Beaufort's Dyke is a submerged tunnel valley caused by glacial erosion during the last glacial period, and has been prevented from filling with sediment by strong tidal currents.[1]

Dumped munitions
Beaufort's Dyke, showing the position of the munitions dump, from an Admiralty chart published in 1913. Depth in fathoms

Because of its depth and its proximity to the Cairnryan military port, Beaufort's Dyke became the United Kingdom's largest offshore dump site for surplus conventional and chemical munitions after the Second World War: it had been used for the purpose since the early 20th century. The Ministry of Defence estimated that well over a million tonnes have been dumped there.[2] In July 1945, 14,500 tonnes of 5-inch (130-millimetre) artillery rockets filled with phosgene were dumped.[3]

Munitions have since been deposited by the tide on nearby beaches. In 1995, phosphorus bombs washed up on Scottish coasts, coinciding with the laying of the Scotland-Northern Ireland pipeline (SNIP), a 24-inch (610-millimetre) gas interconnector constructed by British Gas. In the prior five years, antitank grenades had been washing up on Northern Irish and Isle of Man shores.[4]

An explosion was registered as a 2.5 Magnitude earthquake on 08 Feb 1986 https://earthquake.usgs.gov/earthquakes/eventpage/usp0002qu8/executive

Nuclear waste

According to documents from the Public Record Office, approximately two tonnes of concrete-encased metal drums filled with radioactive laboratory rubbish and luminous paint were dumped in the dyke during the 1950s.[5]

Crossings

Projects for a tunnel or Irish Sea fixed crossing between Northern Ireland and Scotland have been suggested at various times from the late 19th century onwards. The dyke has always been an important problem for such proposals, in terms of both practicality and cost.[6]

In February 2020, the UK government announced an initial investigation into a Scotland–Northern Ireland bridge. Two possible routes were proposed: Portpatrick–Larne and Kintyre peninsula–Torr Head. The Portpatrick route would cross the dyke.[4] Explosive ordnance advisers Exord cast doubt on the Portpatrick route saying “any intrusive works such as piling associated with the construction of bridges would pose an unacceptable level of risk”.[7]

References
  1. Callaway, Alexander; Quinn, Rory; Brown, Craig J.; Service, Matthew; Long, David; Benetti, Sara (May 2011). "The formation and evolution of an isolated submarine valley in the North Channel, Irish Sea: an investigation of Beaufort's Dyke" (PDF). Journal of Quaternary Science. 26 (4): 362–373. doi:10.1002/jqs.1460.
  2. "UK's undersea 'ticking timebombs'". BBC. 26 November 2004. Retrieved 10 September 2019.
  3. Dr. Lewis Moonie, Member for Kirkcaldy (23 April 2002). "Beaufort Trench (Mustard Gas)". Parliamentary Debates (Hansard). House of Commons. col. 192W–193W.
  4. Edwards, Rob (10 February 2020) [1995]. "The WW2 bombs dumped off western Scotland washing up on beaches". New Scientist. Retrieved 11 February 2020.
  5. Arthur, Charles (1 July 1997). "Ministers admit nuclear waste was dumped in sea". The Independent. London: INM. Retrieved 29 April 2015.
  6. Walker, Stephen (2 March 2018). "Bridging the gap from NI to Scotland". BBC. Retrieved 10 September 2019.
  7. Sabbagh, Dan (14 February 2020). "Bombs dumped in Irish Sea make bridge plan 'too dangerous'". Retrieved 16 February 2020.
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