Sea level and coastal change in Great Yarmouth, Norfolk

British coastal areas contain a variety of important resources. These may include wind farms, marine aggregates and sensitive habitats in the offshore zone and buildings, scenic landscapes and sensitive habitats on land.

In order to manage these resources we need a good understanding of how coastal features and sediment dynamics have changed through time and how they are likely to change in the future.

This is especially important in areas such as the Great Yarmouth region of Norfolk where the coastal geomorphology (the Great Yarmouth spit) protects low-lying inland areas (the Norfolk Broads) from extensive flooding.

The Crown Estate-Caird Research Fellowship (involving the Crown Estate, National Maritime Museum and British Geological Survey) has examined coastal change in the Great Yarmouth area during the Holocene period.

Results

To understand the history of the Great Yarmouth spit, borehole records were used to build a 3D model for the pre-Holocene surface (topography) across the area.

Historic maps and aerial photographs were also used to investigate more recent changes in coastline position.

3D modelling reveals a wide estuary that would have intersected the coast in the region of Great Yarmouth at the start of the Holocene. This was flooded by the sea before the formation of a sand and gravel barrier and, latterly, a spit across the valley mouth.

Shorter-term fluctuations in the Great Yarmouth spit are more localised with different areas of the spit displaying different trends.

1884 — 2007 mean high water marks

For example, coastline retreat followed by a period of relative stability typified trends at Caister-on-Sea between 1800 and 2007 whilst North Denes showed seaward advance of the coastline after a period of erosion prior to 1890.

Predicted regional changes in sea-level and storminess are likely to cause some landward retreat of the coastline along the spit.

What is a coastal spit?

Great Yarmouth spit

A coastal spit is an elongate ridge composed of varying proportions of sand and gravel which is connected to the coast at one end and is not completely submerged at high tide.

In the case of the Great Yarmouth spit, the River Yare separates the spit from the mainland at its western and southern extremities and it is bounded by the sea to the east.

Contact

Contact Hannah Evans for more information