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Special Areas of Conservation

Solway Firth

Designated Special Area of Conservation (SAC)
Country England/Scotland
Unitary Authority Cumbria, Extra-Regio, South Western Scotland
Centroid* NY144648
Latitude 54.97083333
Longitude -3.336666667
SAC EU Code UK0013025
Status Designated Special Area of Conservation (SAC)
Area (ha) 43676.16
* This is the approximate central point of the SAC. In the case of large, linear or composite sites, this may not represent the location where a feature occurs within the SAC.
Location of Solway Firth SAC

General site character

  • Tidal rivers, Estuaries, Mud flats, Sand flats, Lagoons (including saltwork basins) (90%)
  • Salt marshes, Salt pastures, Salt steppes (10%)

Download the Standard Data Form for this site as submitted to Europe (PDF <100kb)

Note When undertaking an appropriate assessment of impacts at a site, all features of European importance (both primary and non-primary) need to be considered.

Annex I habitats that are a primary reason for selection of this site

  • The Solway is representative of sublittoral sandbanks on the coast of north-west England/south-west Scotland. The sandbanks comprise mainly gravelly and clean sands, owing in part to the very dynamic nature of the estuary. The inner estuary contains constantly changing channels, and a predominance of sand is characteristic of such high-energy systems. There is a transition to less extreme conditions in the outer estuary. The dominant species of the infaunal communities comprise different annelid worms, crustaceans, molluscs and echinoderms, depending on the nature of the substrate. For example, the bivalve molluscs Fabulina fabula and Spisula subtruncata occur at the edge of sandbanks in fine and medium sand respectively. These communities are richer in the less extreme conditions of the outer estuary.

  • 1130 Estuaries

    The Solway is a large, complex estuary on the west coast of Britain. It is one of the least-industrialised and most natural large estuaries in Europe. Tidal streams in the estuary are moderately strong and levels of wave energy can be high. There is considerable seasonal fluctuation in water temperature, owing to the shallow nature of the estuary. The sediment habitats present, mainly dynamic sandflats and subtidal sediment banks, are separated by six main river channels, which are continually changing their patterns of erosion and accretion. The sublittoral sediment communities are typically sparse in the inner estuary, owing to the mobility of the sediment coupled with low and variable salinity. Communities become richer towards the outer estuary, where there are less extreme environmental conditions and more varied substrates. The dominant species of bivalve molluscs, polychaete worms, crustaceans and echinoderms vary, depending on location within the estuary.

  • The Solway Firth is representative of highly mobile, predominantly sandy intertidal flats on the west coast. It contains the third-largest area of continuous littoral mudflats and sandflats in the UK. These occur within a natural estuary system substantially unaffected by human activities, such as industrial development and dredging. The Solway is an unusually dynamic estuarine system, with mobile channels and banks. Fine sandy sediments occur in the inner estuary, and more stable and diverse conditions in the outer reaches. Salinity ranges from fully marine to estuarine in character, and these gradients in physical conditions add to the ecological diversity within the site. The presence of intertidal sediment flats of fine sands, rather than muds, in conditions of estuarine salinity is a notable feature.

  • The pioneer glasswort Salicornia spp. saltmarsh in the Solway is part of a complete sequence of saltmarsh types, from pioneer communities through extensive mid-to high saltmarsh and transitions to tidal grazing marsh. It represents Salicornia and other annuals colonising mud and sand in north-west England and south-west Scotland. The pioneer marshes in this site develop in response to changing river channels and erosion of existing marsh and form part of a dynamic suite of maritime habitat types for which the site has been separately selected.

  • The Solway Firth, between north-west England and south-west Scotland, has been little affected by enclosure, with the result that it demonstrates unusually large areas of upper marsh and transitions to freshwater grassland communities. There is a greater proportion of sand in the substrate than is found in more southern saltmarshes. The mid-upper marsh is heavily dominated by saltmarsh rush Juncus gerardii community with smaller areas of the saltmarsh-grass/fescue Puccinellia/Festuca communities. The site has been selected because of its large size and uninterrupted transitions. Some of the species present, for example sea-purslane Atriplex portulacoides, common sea-lavender Limonium vulgare and lax-flowered sea-lavender Limonium humile, are at their northern limit in the UK.

Annex I habitats present as a qualifying feature, but not a primary reason for selection of this site

Annex II species that are a primary reason for selection of this site

  • 1095 Sea lamprey Petromyzon marinus

    The Solway Firth provides migratory passage for sea lamprey Petromyzon marinus to and from spawning and nursery grounds in a number of rivers, including the Eden which is designated as a cSAC for the species.

  • 1099 River lamprey Lampetra fluviatilis

    The Solway Firth provides migratory passage for river lamprey Lampetra fluviatilis to and from spawning and nursery grounds in a number of rivers, including the Eden which is designated as a cSAC for the species.

Annex II species present as a qualifying feature, but not a primary reason for site selection

  • Not Applicable

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