No abstract

Relative sea‐level fluctuations during the Holocene period have combined with medieval to present saline floodplain embanking to reduce the inter‐tidal saltmarsh area in Essex from 40 000 ha to 4400 ha. The present loss by erosion is estimated at 2%/annum for the country, and the reduction in these areas is not only detrimental to related habitats but has caused an increasing requirement for flood‐defence financial investment. Recent initiatives by the Ministry of Agriculture, Fisheries and Food, the Environment Agency and English Nature have created mechanisms and opportunities to develop sustainable flood‐control structures where coastal re‐alignment has been the preferred option. The Orplands frontage covers 2 km of sea wall which have been deliberately breached to allow 40 ha of rare saltmarsh to re‐establish. At Abbotts Hall, an arable field of 20 ha has been converted to its former saltmarsh by creek re‐establishment and tidal inundation by reversal of existing sluices. These two schemes have (a) regenerated habitats for halophytic and semi‐halophytic plants, marine and brackish invertebrates, and (b) provided roost, feed and breeding areas for birds and nursery areas for marine fish fry. Apart from flood control and habitat creation, particular features were incorporated to provide niche locations for targeted types of wildlife.

No abstract

Approaches to coastal management have focused increasingly on ‘soft’engineering methods such as beach/foreshore recharge or the managed realignment of coastal defences. In this context, the creation/maintenance of salt marshes is often seen as being of ecological and flood‐defence importance. However, until recently, no field data of wave attenuation over Northern European salt marshes had been available; therefore the debate on the sea‐defence value of salt marshes has remained highly speculative. This paper (a) reviews results from a field and numerical modelling study at Stiffkey, north Norfolk, (b) presents a scientifically based argument for the evaluation of salt marshes as part of sea‐defence schemes, and (c) discusses the relationship between hydrodynamic parameters, salt‐marsh surface characteristics, and possible management implications and engineering guidelines.