Hurd's Deep Explained

Hurd's Deep (or Hurd Deep) is an underwater valley in the English Channel, northwest of the Channel Islands. Its maximum depth is about 180 m (590 ft; 98 fathoms), making it the deepest point in the English Channel.

Toponym

The feature was named after the British Royal Naval Captain Thomas Hurd (1747–1823), who was the second Hydrographer of the Navy. It was chosen by the RN marine cartographer Admiral Martin White.[1]

Geology

Hurd's deep began to form in the Pleistocene of the late Quaternary period (in the last 750,000 - 500,000 years). Successive melting periods after ice ages caused water to gouge out a deep water trench through a river valley system that now forms the seabed in the eastern part end of the English Channel. At some point a catastrophic flood from the southern North Sea basin created Hurd's Deep. It's believed that the collapse of a chalk ridge that once dammed the Strait of Dover let flood waters from a huge proglacial lake flow through the former river systems scouring down to the bedrock forming the trench.[2] [3]

During the Last Glacial Period, which ended 11,700 years ago, sea levels dropped again to the point that the English Channel became an area of river valleys. Due to its depth, Hurd's Deep likely remained flooded by seawater. It might have been a glacial refugium.[4]

Hurd's Deep has an approximate length of 150round=5NaNround=5 with a width of between 2and. It terminates abruptly at the western end. The seafloor around the trench is typically flat with a depth range of NaN-1NaN-1. But within the trench the maximum depth is 170m (560feet).[5] Hurd's Deep is the deepest point in the English Channel.

History

Deep sea ordnance disposal

Following the First World War, Hurd's Deep was used by the British Government as a dumping ground for both chemical and conventional munitions.[6] Following the Second World War, it was used to dump military equipment, munitions and weaponry left behind by the ousted German invaders of the Channel Islands.[7] Routine dumping of British munitions carried on until 1974.[6] [8]

Between 1946 and 1973 the area was also used for the dumping of low- and intermediate-level radioactive wastes. 28,500 barrels of waste – including plutonium, which has a half-life of 24,100 years – were disposed of into the Deep during this period.[9] [10]

Wrecks

was scuttled there in 1921. The British submarine sank in Hurd's Deep in 1951 with the loss of 75 lives.[11]

In popular culture

In Harry Collingwood's science fiction stories about the Flying-Fish airship-submarine, the Flying-Fish is hidden in Hurd's Deep between adventures.

Citations

References

Further reading

49.5°N -37°W

Notes and References

  1. Martin White RN. La Société Jersiaise. Martin. Davies. 1973. 3 March 2019. live. https://web.archive.org/web/20190227221412/https://www.theislandwiki.org/index.php/Martin_White_RN. 27 February 2019. dmy-all. The Island Wiki.
  2. Smith. Alec J.. A catastrophic origin for the palaeovalley system of the eastern English Channel. Marine Geology. 1985. 64. 1–2. 65–75. 10.1016/0025-3227(85)90160-4. 1985MGeol..64...65S.
  3. Gupta. Sanjeev. Collier. Jenny S.. Palmer-Felgate. Andy. Potter. Graeme. Catastrophic flooding origin of shelf valley systems in the English Channel. Nature. 2007. 448. 7151. 342–345. 10.1038/nature06018. 17637667. 2007Natur.448..342G. 4408290 .
  4. Provan. Jim. Bennett. K.D.. Phylogeographic insights into cryptic glacial refugia. Trends in Ecology and Evolution. 2008. 23. 10. 564–571. 10.1016/j.tree.2008.06.010. 18722689.
  5. Book: Geology of Siliciclastic Shelf Seas. De Batist, M. . Jacobs, P.. Geological Society. 117. 7 October 1996. Detailed survey of the western end of the Hurd Deep (English Channel): new facts for a tectonic origin. Lericolais. G.. Guennoc. P.. Auffret. J. P.. Bourillet. J. F.. Berne. S.. 978-1897799710.
  6. Replacement Metallic Return Conductors - Marine Environmental Report. December 2014. 16 August 2019. D3–D4. 4. live. https://web.archive.org/web/20190816073956/http://www.mutual-energy.com/downloads/moyle-repair-project/er-vol4.pdf. 16 August 2019. dmy-all. Moyle Interconnector Ltd.
  7. Book: Carr, Gilly. Legacies of Occupation: Heritage, Memory and Archaeology in the Channel Islands. 30. 7 March 2014. 978-3319034065. Gillian Carr.
  8. News: Alderney Hurd Deep radioactive waste 'not dangerous'. 15 August 2019. 18 April 2013. BBC. live. https://web.archive.org/web/20160213232035/https://www.bbc.co.uk/news/world-europe-guernsey-22198566. 13 February 2016. dmy-all.
  9. http://news.bbc.co.uk/1/hi/sci/tech/1766365.stm Nuclear dumping leak sparks concern
  10. Web site: Thousands of radioactive waste barrels rusting. Greenpeace. https://web.archive.org/web/20090628103243/http://www.greenpeace.org.uk/media/press-releases/thousands-of-radioactive-waste-barrels-rusting-away-on-the-seabed. 28 June 2009. dead. 19 June 2000. dmy-all.
  11. News: 1951: Fears for crew of lost British submarine . 17 April 1951 . 31 December 2007 . https://web.archive.org/web/20080307120444/http://news.bbc.co.uk/onthisday/hi/dates/stories/april/17/newsid_2847000/2847935.stm . 7 March 2008 . live .

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