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Dengie experimental saltmarsh restoration
Sales Point, Marsh House and Deal Hall are three locations along
the Dengie peninsula, Essex. At each site the approach was different:
- Sales Point - 11 Thames lighters were placed 200m offshore,
spaced 20m apart, to create a wavebreak 'protecting' 600m of eroding
saltmarsh were installed in 1986. In 1989 shore-lighter connecting
brushwood groynes were erected;
- Marsh House - 16 Thames lighters were placed 500m offshore,
spaced 20m apart, in 1984. Two groynes (clad with geotextile material
rather than the traditional brushwood) were constructed in 1986
at either end of the wavebreak. Spartina
was also planted in 'gripped'
areas towards the landward side of the polder (see picture opposite);
- Deal Hall - Two 400m square polders were constructed
in 1980 using brushwood groynes. The enclosed tidal mudflats were
'gripped' in 1981 and again in 1989. A third polder was constructed
1987/8 but not 'gripped'.
Caption:
Marsh House polder. Note the sunken barges in the distance.
Comment: Preliminary results and descriptions of these
sites (Holder
& Burd 1990) suggested that their effectiveness
was patchy. More recent inspection (see Cudmore
Grove) suggest that they may have made little difference
to the establishment of new saltmarsh. These and other restoration
sites might repay further investigation especially where they
now form part of realignment schemes, such as at Orplands.
References
Holder, C.L. & Burd, F.
1990.
Overview of Saltmarsh Restoration Sites in Essex: an Interim Report.
Nature Conservancy Council.
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