MMO1135 Potential Habitat Creation Sites Within the Current Floodplain

Currently defended floodplain areas in England which could be suitable for managed realignment and / or Regulated Tidal Exchange (RTE) (to create mudflats and saltmarshes) are identified. Polygon data developed in 2018, by excluding /deleting unsuitable areas from the base layer (the Environment Agency's floodplain layer). Unsuitable areas included urban areas, major infrastructure, and existing managed realignment sites. With regard to limitations, this datalayer should only be viewed as a high level indication where managed realignment or RTE may be feasible. Sites are not ranked according to their suitability, nor does the layer indicate whether or not land is actually available for intertidal habitat creation (e.g. landowners may well not be interested to sell). Whilst a validation exercise showed that using the Floodplain 3 datalayer would generally lead to the identification of sites which could support mostly intertidal habitat if they were breached, the likely actual habitats achieved would depend on the regional and site conditions. Further investigations should be undertaken once a site has been judged as being of potential interest. Further limitations of the datalayer include that the larger sites identified are unlikely to be suitable for intertidal habitat creation across their entirety, for example due to potential difficulties relating to getting water to all areas of the site, or because very large sites may have undue impacts on the adjacent estuary. Thus, in reality, large sites will likely need to be sub-divided, and those areas closer to the shoreline preferentially targeted. RTE tidal amplitude is also generally lower than for fully breached sites, and with any site identified for RTE, it is thus unlikely that the full extent of a given site included in the datalayer would be inundated.