Funded by INTERREG IIIB North West Europe

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Branch - Coastal Work Package Sea-Level Rise and
Coastal Habitats - impacts and adaptation
assessment Sarah Gardiner, Robert J. Nicholls,
Julie Richards - University of Southampton Simon
Jude, Zhong Zhang, Andy Jones - University of
East Anglia Alan Williams, Pennie Smith -
Hampshire County Council Isabelle Rauss, Pascal
Hacquebart Conservatoire du Littoral
Funded by INTERREG IIIB North West
Europe www.branchproject.org
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Outline

• Introduction to the Coastal Work Package
• Scale of Project
• Objectives of Coastal Work
• Case Study Sites (UK and France)
• Case Study Example (UK)
• Key Issues
• Conclusions

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Information at a number of levels

• Information available at a habitat and species
  scale
• At local, regional, national, Northwest Europe
  and EU25
• Using different emissions scenarios for climate
  impacts
• Over different timescales (2020, 2050, 2080)
• But different analysis at different levels

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Objectives of the Coastal Work

• To develop a transferable methodology to assess
  the potential impact of sea-level rise on
  designated coastal habitats.
• To apply this methodology at case study sites in
  France and UK.
• To examine adaptation options for habitats.
• To extend the methodology to the regional scale
  and examine potential mitigation sites in the UK.
• To engage relevant stakeholders, including novel
  communication tools.
• To provide information and guidance for coastal
  managers and strategic planners.
• Note that species level change is also considered
  (by ECI, Oxford University).

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Case study sites in France and UK
1.Studland 2.Pennington 3.Isle of Wight
Cliffs 4.Newtown Estuary 5.Hamble
Estuary 6.Langstone Harbour
French Case Study Sites
1.Baie du Mont Saint-Michel 2.Havre de
Regnéville 3.Mare de Vauville 4.Utah Beach 5.Baie
des Veys 6.Ver-sur-mer 7.Graye-sur-mer
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Modelled Saltmarsh Distribution
Present Day
Medium High Scenario
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Present day
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Med/High Scenario 2080
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Managed Realignment Options
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UK Key Issues

• All sites experience either gains or losses
• Coastal grazing marsh especially threatened
• Saltmarsh/intertidal flats more amenable to being
  engineered
• What scale of assessment?

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Integrated Habitat Assessment Approach at Cell 5
Level
Influenced by Planning
Coastal Grazing Marsh
Saline Lagoons
Managed Realignment Unplanned Realignment
Erosion Submergence
Saltmarsh
Mudflat
Sedimentation
Erosion
Sedimentation
Erosion Submergence
Open Water
Plus artificial creation of compensatory Fluvial
Grazing Marsh within river floodplains (if
possible)
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Example of fluvial relocation of coastal grazing
marsh within Cell 5
Approximately 29,000 ha floodplain available for
habitat recreation (at a loss to other habitats
or agricultural land)
Un-designated areas within the fluvial
floodplain
Existing floodplain grazing marsh
Floodplain within cell 5 after extracting urban
and already designated areas
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Conclusions

• Current losses of intertidal habitats will be
  exacerbated by accelerated sea-level rise.
• There are re-creation opportunities behind sea
  defences, but they are more limited than cursory
  analysis suggests
• Competition between designated habitats, e.g.,
  grazing marsh and saltmarsh
• Often low-lying land, unsuitable for saltmarsh
  creation
• Land use conflicts.
• To sustain coastal habitats a wider and
  longer-term view is required.
• Scope for soft engineering to raise low-lying
  realigned areas.
• Coastal grazing marsh presents particular
  problems can we substitute with fluvial grazing
  marsh?
• Use of this research is leading to better spatial
  planning decision-making across Europe.

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A partnership project
www.branchproject.org