Elmer Rock Groynes

The old wooden groynes at Elmer proved ineffective in maintaining the shingle beach. In order to address the problem offshore breakwaters were installed. The shore defences at Elmer are examples of these breakwaters (see South Downs Coastal Group).

Elmer: Aerial view east

Elmer: Aerial view east

This approach as been used to stabilise the coastline at a number of places in the UK including Leasowe Bay on the Wirral, Monk’s Bay on the Isle of Wight, between Happisburgh and Winterton in Norfolk, and at Elmer, West Sussex. The bulk of the work was carried out 1992/3 involving 200,000 cubic metres of shingle and 100,000 tonnes of rock.
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Each ‘breakwater’ is created by forming ‘reefs’ from mounds of rubble and represent a simple design solution for the stabilisation of the renourished frontage at Elmer. The breakwaters reduce wave energy in the lee of the structures allowing the beach to evolve into a responsive barrier stopping the sea from overtopping the old seawall with subsequent flooding but allowing some littoral drift to carry on. Sand and gravel salients (coastal formation of beach material resulting from wave refraction and diffraction) have formed in the lee of each breakwater separated by broad embayments.

Elmer rock groyne looking west

Elmer rock groyne looking west

Drift is reduced considerably compared to the open coast, but studies have demonstrated that some sediment may pass through the scheme at the salients. The salient and bay systems developed to a greater degree than was originally anticipated and some remedial works have been required. By 2001 the scheme had very effectively intercepted drift from the west and a wide stable foreshore has formed along this sector.
For further information see: Ecological impact of coastal defense structures on sediment and mobile fauna…  Advances in Coastal Structures… and Application of Offshore Breakwaters to the UK: A Case Study at Elmer Beach

Sponges
Halichondria panicea      Breadcrumb sponge
Dysidea  fragilis              Goosebump sponge
Cnidaria
Actinia equina                 Beadlet anemone         Both red and green varieties
Anemonia viridis             Snakelocks anemone   Both green / purple and grey varieties
Actinothoe sphyrodeta   Sandaled anemone      White anemone in deep crevices
Sertularia sp                       Whiteweed
Dynamena pumila         a seafir
Kirchenpaueria pinnata  a seafir
Worms
Lanice conchilega         Sand mason
Arenicola marina           Lugworm
Spirorbis sp                   Spiral worm
Eulalia vividis                Green  leafworm,   eggs

Molluscs
Crepidula fornicata       Slipper limpet
Gibbula cineraria         Grey top shell
Gibbula umbilicalis       Purple top shell
Littorina saxatilis          Rough winkle
Littorina littorea             Edible winkle
Nucella lapillus             Dog whelk
Patella vulgata              Limpet
Pholas dactylus            Piddock, holes
Buccinum undatum      Common whelk,  eggs; drift only
Mytillus edulis               Blue mussel
Crustacea
Carcinas maenas         Shore crab
Austrominius modestus    Darwin’s barnacle
Pagurus bernhardus    Hermit crab
Palaemon elegans      A prawn
Bryozoa
Electra pilosa               Frosty sea mat
Bugula sp
Sea squirts
Styela clava                 Leathery sea squirt, drift only
Corella eumyota          a sea squirt
Ascidiella sp.               a sea squirt, drift only
Fish
Juvenile flatfish          ? Pleuronectes platessa, Plaice
Fish fry
Scyliorhinus canicula  Lesser spotted dogfish/Cat Shark, eggcase
Ray     eggcases
Seaweeds/algae
Saccharina latissima    Sugar kelp
Enteromorpha sp         Gutweed
Ulva lactuca                 Sea lettuce
Fucus serratus             Serrated wrack
Fucus vesiculosus        Bladderwrack
Chondrus crispus         Irish Moss
Corallina officinalis       Coralweed
Hildenbrandia sp
Crustose pink algae     various species
Furcellaria lumbricus    Clawed Fork Weed
Colpomenia peregrina  Oyster Thief    * interesting record
Mastocarous stellatus   Grape Pip Weed, drift only

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