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Moving from Accretional or semi-stable (State 2) to Erosional
(State 1) beaches
A key issue when considering the restoration of coastal shingle lies in determining
the principle aims, and whether these are for sea defence purposes or nature
conservation and amenity. Whilst coastal defence requirements seek to create
stable structures, there is an increasing recognition of the value of allowing
the natural dynamic to reassert itself. It has been argued that this can be
a healing force in degraded systems, especially where the surface shingle has
been removed or grossly disturbed (Doody 1992b).
A number of scenarios can be identified:
- Breach in a shingle bar with associated 'roll-back' and flooding of the
land behind. An example of this is Porlock
Weir in north Somerset;
- Rollover
of a shingle barrier onto terrestrial land (including grazing marsh), tidal
areas (including lagoons) or other coastal habitats;
- Remobilisation of progressive ness formation which has been arrested by
artificial interference with its natural progression. An example is Dungeness
where erosion takes place from west to east as the ness attempts to move in
an easterly direction. Beach
nourishment is used to keep the beach in front of the power station
in situ.
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Guidance: At the present time this is a little used and little
understood method of restoration. However given the major losses that
have occurred at many of the larger sites it is a change that could generate
considerable conservation benefit.
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References
Doody, J.P.
1992b.
Sea defence and nature conservation: threat or opportunity.
Journal of Aquatic Conservation, 2., 275-283.
Abstract...
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