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Severn Estuary Special Area of Conservation (SAC)

Severn Estuary SAC Zone of Influence Map 2017 (7.7km)

The Severn Estuary is one of the largest estuaries in Europe and is internationally important for the habitat and species the estuary supports. Saltmarsh fringes the coast backed by grazing marsh with freshwater ditches and occasional brackish ditches. The subtidal seabed is rock and gravel with subtidal sandbanks. The site also supports reefs of the tube forming worm Sabellaria Alveolata.  The estuary's classic funnel shape, unique in the UK, is a factor causing the Severn to have one of the highest tidal ranges in the world. A consequence of the large tidal range is an extensive intertidal zone, one of the largest in the UK. The site qualifies as a Special Area of Conservation (SAC) for a range of coastal habitats and for three fish species. The Severn Estuary Special Protection Area (SPA) is classified for its waterbird assemblage and for a range of species that occur on passage/over winter including a range of both wildfowl and wader species. The Ramsar interest overlaps with the SAC and SPA features and includes the bird interest.

The bird populations associated with the estuary move widely and make use of a range of sites away from the estuary during the course of the winter. Waterbodies, wetlands and low-lying farmland within the can provide important feeding and roost sites which may vary in importance within a season and across years, depending on water-levels, food availability and a range of other factors. While such sites lie outside the SPA they are functionally linked in that they play a role in supporting the relevant bird interest. Key locations within the Vales are described by Palmer and Smart (2021) who identified 21 sites that held more than the equivalent of 1% of the SPA population of one or more species for 50% or more of months within one or more of three WeBS counting seasons. 

A new visitor survey report was therefore commissioned in 2022. It was recognised that while baseline levels of recreational pressure on the Estuary are relatively low, disturbance would still have a high impact and recreational use was likely to increase with new housing, employment and tourism. A likely significant effect on the conservation status of the SPA’s qualifying features could not be ruled out in the 2021 HRA. Whilst there is an established a mitigation strategy (Stroud District Council, 2017)  the Council recognise a review and update would be required.  This work was completed in March 2024 and the Council adopted the new mitigation strategy at Environment Committee on the 21 March 2024. The 2022 visitor survey results  helped inform the production of an updated mitigation strategy. The new strategy will seek to address the cumulative effects of housing growth across a wide area, spanning multiple authorities in Gloucestershire.

Payment of this obligation is secured through agreed planning obligation S106.

This will apply for applications submitted from 31st May 2024. The old 2017 mitigation strategy will remain in place until then, so there is no mitigation policy gap.


Severn Estuary SAC Zone of Influence Map 2024 (21.6km):

Last reviewed: