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Beach nourishment - summary
Beach nourishment is a generic term used to describe the placement of sediment
on depleted beaches as a means of counteracting erosion. In some cases, especially
those associated with shingle recharge the approach may be concerned solely
with improving sea
defence. More usually and especially in relation to the creation
of tidal sand and mud flats it is combined with attempts to re-create tidal
habitat for conservation
purposes. It tends to be associated with a sea defence policy of
'Hold
the Line'. Four types of nourishment can be identified:
- Beach nourishment with sand, as on the Lincolnshire coast (Zwiers
et al. 1996) or the Netherlands;
- Recycling shingle and/or sand, as for example is employed at Dungeness;
- Sediment by-pass, sand/shingle;
- Use of dredged
material to re-create tidal sand/mud flats and/or help with the
creation of saltmarshes.
Examples of creating tidal flats/saltmarsh with dredged silty
material:
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Guidance: Where coarser sediments, such as shingle are involved
the method itself can cause damage at the extraction point and may change
the sediment patterns in adjacent areas. Care must be taken to ensure
that these changes do not create adverse environmental consequences.
Beach recharge using finer material can be successful but is not without
its drawbacks. Amongst these the toxicity of some sediments derived from
estuarine sources can be particularly problematic in polluted estuaries.
These impacts can be avoided (at least for dredged material) with careful
foreshore recharge
management.
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Caution: Models are often used to determine
the nature of the nourishment operation but some argue that practical experience
provide an alternative,
if not better approach.
References
Zwiers, M., Dales, D. & Hunt, H.
1996.
Mablethorpe to Skegness beach nourishment: is it working?.
In: Partnership in Coastal Zone Management, ed.Taussik, J. & Mitchell, J.Samara Publishing Ltd. Cardigan, 631-637.
Abstract...
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