Shingle State 1, Erosional beaches

This state is set to be represented in those situations where a beach is more or less constantly eroding. Vegetation develops between erosion episodes when annual vegetation of drift lines (an important community within the Natura 2000 classification) becomes established. These sites are characterised by having a dynamic beach, which is moving alongshore or landward under the influence of the sea. They may have beaches with low cliffs or steep shelving shores and high ridge crests. The precise form depends on balance between sediment availability, relative sea level rise and longshore drift. The typical form is present on many shingle beaches throughout the UK, but especially on the south coast where protective structures are frequently found.

The key feature for most sites is that the sediment supply is restricted. Sea level rise and/or changes in the vulnerability of the structure brought about by gravel extraction, result in undermining by the action of waves especially during storm events. In this state natural movement may be to 'roll-over' landwards especially where sea level is rising relative to the land (see picture opposite).

Caption: The eastern end of the shingle ridge at Porlock, Somerset. At this point the shingle is regularly disturbed by storm waves hence the absence of vegetation. At the western end the beach has been maintained in the past by groynes and periodic bulldozing (reprofiling) to raise the crest height. This is one of six casework sites (Annex 01) reviewed under contract to English Nature as part of the "Guide to the management and restoration of coastal vegetated shingle".

Comment: The value of the eroding shingle is also one of the key issues being addressed by the Living with the Seas Project CHaMP for North Norfolk and at Dungeness.

Caveat: Beaches which are attempting to 'roll-over' landward may be in a state of dynamic equilibrium in relation to sediment availability. These sites should be classified as being State 2 Accretional but will be in an unstable equilibrium.