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The IMCORE project ran from 2008 to 2011 and was funded under the EU Interreg IVB programme.

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The Severn Estuary lies on the west coast of the British Isles and separates South West England from South Wales. It is Britain's second largest estuary (557 km2) with an extensive catchment, extending into the English Midlands and into Mid-Wales. It boasts the highest tidal range in Europe with a tidal regime which causes strong tidal streams, mobile sediments and the famous Severn Bore. For more information click here.

An important natural environment

The Severn Estuary is extremely diverse with extensive areas of open, low lying coast, salt marshes and tidal flats as well as offshore islands. It is well known for nature conservation (a Natura 2000 site: click here for more information), being internationally important for migratory fish (e.g. salmon and the rare shad) and migratory birds (e.g. the Bewick's swan and the European white-fronted goose).

Urban and industrial uses

Over one million people live close to the estuary's shores, mainly in the lowlying cities of Cardiff, Newport, Bristol and Gloucester. There are also major ports (Bristol, Newport, Cardiff, Barry) and port-related installations as well as other industries such as chemical processing plants and power stations. Deep-water channels, cooling water, cheap waste disposal and offshore aggregates (for construction) are the estuary's natural 'resources' for such activities.

Tourism and recreation value

The estuary has a number of seaside resorts (Clevedon, Weston-super-Mare, Barry, Penarth), fashionable waterfronts (Gloucester Docks, Cardiff, Bristol) as well as facilities for offshore recreational activities, such as sailing.

A future renewable energy resource?

The very large tidal range on the estuary means that there is frequent debate over the potential for offshore tidal energy generation. For more informationa on tidal power in the Severn estuary click here. However, a major government review within the IMCORE project timeline stated that it is not currently timely to develop a Severn tidal power scheme, given associated costs and risks.

A rich maritime heritage

As the Severn Estuary region has been a focus for settlement and trading over centuries, the estuary boasts a rich archaeological and maritime history including exceptional maritime discoveries of Bronze, Medieval and Roman age. Find more information here.

A complex estuary to manage

The estuary has been described as an 'estuary of contrasts'. Given the broad range of uses, it faces many complex, inter-related issues and potential conflicts many of which are likely to be exacerbated in the context of climate change. The cross-border nature of the estuary also poses additional challenges for management and for taking an integrated approach, particularly as there are many different organisations, plans and policies for the English and Welsh sides of the estuary.

Drivers of climate change

The Severn Estuary Partnership's Management Group identified the following key drivers & issues:

  • Sea level rise
  • Storm surges

 

These pose serious issues for the estuary as much of its population, industry and related infrastructure is at or close to current sea level. Storms and storm surges have occurred throughout history on the Bristol Channel, and have been the cause of substantial damage and flooding from the sea both in the past and more recently.

Based on an in-depth review of current science on climate change drivers on the estuary (including UKCP09 projections and Severn specific research) the Severn Estuary Climate Change Research Advisory Group has demonstrated the following trends and characteristics of these drivers:

Sea level rise – there has been a detectible rise in mean sea levels over the last fifteen years and a rising trend of 2.4mm/yr-1 on the estuary. It is estimated that sea levels will be 30-40cm higher than they are at present by 2080 (based on a medium greenhouse gas emissions scenario).

Storms and storm surges –. Within the Bristol Channel and Severn Estuary the size of surge expected to occur on average about once every 50 years is projected to increase by about 0.8 mm yr (not including relative mean sea level change) over the 21st century. This may be considered insignificant when compared to projected sea level rise. Recent research by Phillips and Crisp has, in fact, shown a decrease in the height of extreme high water in the Bristol Channel/Severn estuary over fifteen years, though there are variations across the estuary.

Analysis of the causes of significant storms and storm surges on the Bristol Channel has identified two specific synoptic meteorological cases:

  • surges caused by strong westerly winds, which can be particularly damaging to the Somerset coast
  • south easterly winds associated with a deep depression or trough close by, such as the events in 1981 and 2008

 

In addition, winds from the east and north east can cause significant damage to the coastline of south Wales, especially Penarth. This wind direction is not the prevailing wind direction (the south west), but is associated with the maximum (north east) fetch for the area.

Further Reading:

Please click here to view the IMCORE Severn Estuary report cards

Please click here to view the UK Climate projections website

Please click here to view the UK Marine Climate Change Impacts Partnership report card

Impacts of climate change in the case study area

One of the most significant threats to the estuary over the next hundred years comes from climate change. Potential impacts widely acknowledged by the estuary community include:

Socio-economic losses - Significant urban development and critical infrastructure on low-lying coasts needs protecting from flooding and the erosion impacts of severe storms.

Maintaining coastal defences – these are extensive, particularly around the Wentlooge and Caldicot levels on the Welsh coast and around the Somerset Levels on the English coast.

Coastal squeeze and habitat loss –a major consideration along developed and defended shorelines. This could result in a significant loss of intertidal habitat and associated internationally important conservation and heritage features.

Clearly, climate change on the estuary has many knock-on, indirect impacts as illustrated in the figure below:

 

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Impacts of climate change on the Severn Estuary (Source: Hovey, 2010)

Major limitations for adaptation:

There are significant issues associated with

  • gaps in the information base– particularly inadequate information on the social and economic characteristics of the estuary. Also, Severn–specific scientific predictions of climate change impacts are limited by monitoring deficiencies and gaps.
  • the complex institutional arrangements of a cross-border estuary - these pose issues for developing a single adaptation strategy, but provide justification for the need to develop a common understanding and approach for this shared estuary
  • the number and range of plans and strategies relating to climate change – many of these incorporate aspects of climate change, making it difficult to produce a single strategy. Plans and strategies include local government climate change strategies, spatial/development plans/frameworks, shoreline management plans and the Severn Estuary Flood Risk Management Strategy.
  • focus on climate change mitigation – many existing plans and organisations consider climate change mitigation as the priority. In the context of the latter, there has also been considerable focus on the tidal energy potential of the estuary recently.
  • different climate change projections – many organisations, plans and strategies around the estuary adopt varying predictions of climate change
  • the 1607 event – scientific opinion is divided as to whether or not the major flood even of 1607 was caused by a tsunami or a storm surge. Considerable media coverage of this has caused disquiet and concern within local community about the possibility of an event of this scale in future. However, the uncertainty regarding the origin of this even has prompted considerable interest in the science of storms on the estuary by many local stakeholders.

 

Further reading:

Click here for the Impacts of Climate Change on the Severn Estuary Inaugural Meeting of the Research Advisory Group

Click here to view the Severn Estuary Climate Change Research Advisory Group meeting reports

ICZM and institutional context

The national ICZM context:

There is no legal requirement for ICZM although ICZM strategies do exist for both England and Wales in line with the EC ICZM Recommendation. However, these appear largely defunct documents, now that the Welsh and UK Governments are focusing more on marine planning under the Marine and Coastal Access Act 2009.

Severn Estuary organisations:

Around the Severn Estuary there are many public, private and voluntary organisations with coastal responsibilities and interests, including government agencies, port and harbour authorities, and local authorities, to name but a few. Many of these bodies have interests confined to particular sectors (e.g. ports and shipping, coastal defence, environmental management) as well as to specific geographical areas (e.g. South East Wales, local authority areas). The Severn Estuary Partnership's 'Who Does What' guide provides information on many of these bodies.

The Severn Estuary Partnership (SEP):

The Severn Estuary Partnership (SEP) was established in 1995 as an independent Estuary-wide non-statutory initiative, led by Local Authorities, Statutory Agencies and Cardiff University. SEP tries to provide an integrated approach and a unique neutral role, linking people and organisations through information provision, publications and projects as well as through attending and promoting meetings and events. Its aims are summarised below.

Severn Estuary Partnership aims:

  •  to facilitate effective communication across and between organisations and individuals
  •  to establish and embed a set of 'common principles' for sustainable estuary use via Partners' strategies, policies and action plans
  •  to act as a co-ordinating body to assist the effective and efficient delivery of agreed estuary-wide actions
  •  to promote and publicise the estuary at local, national and international level
  •  to add value and fill gaps in effective estuary management, providing extra capacity when required.

Click here for more information on servern estauary partnership

Despite SEP's key role, its non-statutory status has frequently resulted in resourcing issues which make taking a long-term perspective to coastal management very difficult.

Other estuary-wide plans:

In addition to SEP, several other sectoral, estuary-wide plans and management initiatives have developed over the last decade in response to a range of legal and other requirements. These include various catchment/river basin management initiatives, the Association of the Severn Estuary Relevant Authorities and associated Management Scheme for the Severn European marine site, the Severn Estuary Coastal Group and related Shoreline Management Plan and the Bristol Channel Counter-Pollution Association (BCCPA). Details of these can be found on the Severn Estuary Gateway website.

Climate change adaptation

Local authorities and climate change:

In line with the Climate Change Act 2008, Local Authorities have a key role to play in preparing for climate change and adapting to its impacts. As Service Providers, Corporate Managers and Community Leaders, they are responsible for a wide range of functions, and as such, are in a unique position to tackle climate change. All local authorities around the Severn have signed up to 'The Nottingham Declaration on Climate Change' in England and 'The Welsh Declaration on Climate Change and Energy Efficiency'.

Local planning authorities and climate change:

Local planning authorities play an integral role in planning for a changing climate, guiding future development and land use decisions. National planning guidance attempts to explain how the land based planning system can play a part in tackling climate change. In addition to specific guidance related to flood risk, there is specific climate change guidance:

  •  In England: 'Planning Response to Climate Change' (2004) and 'Planning Policy Statement: Planning and Climate Change – Supplement to Planning Policy Statement 1' (2007). Click here for more information.
  •  In Wales: Planning Policy Wales (2011) click here to view the website.

Whilst highlighting the current uncertainty as to the precise impacts of climate change, this guidance stresses the need for planning authorities to make ensure that any new development should be adaptable.

Despite national guidance, recent IMCORE reviews have revealed that Severn Estuary local authorities and local planning authorities have taken varying approaches to climate change and have much to learn from each other in relation to climate change adaptation.

This learning portal brings together the results and lessons learned from the IMCORE project. This project was funded under the Interreg IVB programme from 2008 to 2011.

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