The magic 5 metre tide level and its effect on Anglo Saxon History.

Anglo Saxon
History
Map Position

This map is centered on Crawley in Sussex.

Map Logic

This map is shows the 5 metre high tide level around the coast of the South East of England. As you can see there is a marked difference between this map and current maps mainly due to Sea Defence work. The Pevensey and Romney marshes were tidal salt marshes with a few small islands protruding through the water as is the area between Worthing and Fareham.
If our current sea defenses were removed then the coastline would revert to this shape.
This map is created by http://flood.firetree.net and is a brilliant way of visualising historic sea levels even though it wasn't designed for this purpose.


 
 

The map above shows the 5 metre tide level over the South East of England, I will now try to show you why I believe this is relevent to the history of the Saxons.

Lets take an area I know - the Pevensey Levels in Sussex.

and look at the Saxon place names which refer to islands these places are all derived from the Saxon word æg
which has been shown to refer to modern place names starting in eg, ending in ay or et or ey or ly or ney or sea or sey or ye, containing eye or island.
So lets take a look at modern Pevensey and see if we can make it into an island.

The following images are derived from Google Maps with the sea level overlays provided by Alex Tingle http://flood.firetree.net


The map above shows the current sea level, Pevensey is not an island


This map shows what the land would look like if the Sea Level rose by 1 metre, Pevensey is still land based.


This map shows what the land would look like if the Sea Level rose by 2 metres, Pevensey is starting to look more like an island.


This map shows what the land would look like if the Sea Level rose by 3 metres, Pevensey is still not an island.


This map shows what the land would look like if the Sea Level rose by 4 metres, Pevensey is looking more like an island but still not there yet.


This map shows what the land would look like if the Sea Level rose by 5 metres, Pevensey is now an island.

Is this 5 metre mark valid across the country, so lets take a look at the area around the Wash.


This map shows the 5 metre mark near the Wash, as you can see Thorney, Wattlesey, Ramsey, Southery and Ely are all islands with the sea level at this height.

So the logical conclusion is that the high tide level was up to 5 metres higher than today, or the modern sea defenses are blocking this rise.

I think this is a valid argument for a 5 metre sea level so we need to overlay all our maps with this and see what this shows, the map at the top of the page shows what effect this would have on the South East of England. As you will see on the top map, most of the river valleys would have been accessible from the sea, the Romney and Pevensey Marsh areas together with the area around Worthing were salt marshes.

The 'Time Team' carried out a dig at 'Bawsey st Peter' in Norfolk and found a causeway to the island there, this also ties in with the increase in high tide level by about 5 metres, the Saxon name Bawsey either means 'Pasture Island' or 'Boars Island' so more evidence that the 5 metre mark is valid.

Current translation for Crawley
  craw derived from crawe - the bird - crow
  ley derived from æg/leah - an island near the sea / woodland clearing if inland
Place name translation provided by www.saxonhistory.co.ukClick here to use this translation on your website


External References in no particular order :-
Original Manuscripts of the Anglo Saxon Chronicles
Online Anglo Saxon dictionary
Online Etymology dictionary
Open Domesday Book - The first free online copy of the Domesday Book
The Ermine Street Guard Roman re-enactment and research Society
The "Kent A" cadastre - page 5 - Peterson 2002
Archaeologia Cantiana Online
Romney Marsh Research Trust
Romney Marsh the Fifth Continent
VillageNet the reference guide to villages in Kent & Sussex
Global warming Flood Maps
The Anglo Saxon Chronicles
Google Maps - the core of the system
GeoPlaner - Useful site for plotting map data
Julius Caesar's Gallic Wars 55BC(Books 4 & 5)
Wikipedia - Caesar's invasions of Britain
Wikipedia - Portus Istus
The Geography of Claudius Ptolemy (Bill Thayers)
Roman Britain.org
Runetree Beowulf
Bayeux Tapestry Online
The Secrets of the Norman Invasion

 

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Author: Simon M       Document Created: 2016-12-28
Data is derived from a number or sources including the Ordnance Survey Gazetter data overlayed onto Google Maps