Medmerry, West Sussex coastal flooding

The managed realignment project at Medmerry is the biggest on the open-coast in Europe (Image: Environment Agency)
Area characterisation: 

The study area is Medmerry coastline located in south east England. Coastal flooding has long been a problem at Medmerry and a serious risk to the nearby towns of Selsey and Pagham. The previously existing defence, a 3km shingle bank, was subject to regular breach. As well as offering a deficient level of protection, the shingle bank’s maintenance had become costly and unsustainable. An issue in the wider region of The Solent has been the loss of environmentally important coastal habitat, as a result of coastal squeeze. The impacts of development and flood defence infrastructure around the large, urbanised areas of Southampton and Portsmouth have caused local sea levels to rise and wetland and intertidal habitats to be lost to the sea.

Slideshow:

Photo from Google Earth pointing the Medmerry coastline Aerial view of managed realignment at low tide - Photo credit: UK Environment Agency The managed realignment project at Medmerry is the biggest on the open-coast in Europe (Image: Environment Agency)  View of Medmerry showing the location of Selsey and features in the surrounding area (Image: Environment Agency) Excavating the medieval fishweir
Objective: 
  • Sustainable flood risk management: It will provide a higher standard of protection to the area
  • Creation of compensatory intertidal habitat: Delivering 183ha of intertidal habitat, including mudflat, saltmarsh and transitional grassland.
  • Involvement of local communities: Creating new access routes and viewpoints
Actions: 

At first the strategy by UK Environment Agency (EA) to build new inland defences from the existing coastline was not received well from the local community. In response the EA worked with a large group of concerned local people to form the Medmerry Stakeholder

Advisory Group (MStAG), a...

Potential impacts/benefits: 

Enhancing sustainable urbanisation

Restoring ecosystems and their functions

Developing climate change adaptation; improving risk management and resilience

Sustainable development of coastal regions.

Increase awareness of NbS solution & their effectiveness and co benefits.

Increase Biodiversity.

Increase quality and quantity of green and blue infrastructures.

Improve connectivity and functionality of green and blue infrastructures.

Increase achievements of biodiversity targets.

Increased cultural richness

Reduce flood risk.

Better protection and restoration of coastal ecosystems.

Transferability of the result: 

Coastal squeeze remains an issue for other managed realignment schemes, which can be subject to the same erosion processes as natural coastal wetlands. The same methodology of creating water banks can be applied to areas that are in danger by floods. Managed realignment to address intertidal habitat loss or biodiversity still remains debated so it must be studied individually and extensively for every case.

Lessons learned: 
  • Collaboration. The success of this project depended on close collaboration between a wide range of stakeholders which allowed for innovative problem-solving
  • Engaging with local residents early and often to answer questions and address concerns is critical to carrying out a successful project and creates an environment of trust
  • Forming specialist groups to manage complex issues such as habitat management, and archaeological findings that may impact construction timelines are very important for the stakeholder concerns
Contacts: 

Nick GRAY, UK Environment Agency, Worthing, England (nick.gray@environment-agency.gov.uk)

Goals:

  • Restoring ecosystems and their functions
  • Developing climate change adaptation
  • Improving risk management and resilience

NBS Actions:

  • Establishing nature-based solutions for coastal resilience

Keywords:

Better protection and restoration of coastal ecosystems, Biodiversity, Climate change, Coastal, Coastal Resillience, Developing climate change adaptation; improving risk management and resilience, Green space management, Heritage (cultural and natural), Land management, Nature-based solutions, North Sea, Open ocean, Resilience, Think Nature, ThinkNature, Improve connectivity and functionality of green and blue infrastructures, Increase achievements of biodiversity targets, Increase Biodiversity, Increase quality and quantity of green and blue infrastructures, Reduce drought risk, Increased cultural richness and biodiversity, Increase awareness of NBS solution & their effectiveness and co benefits, Restoring ecosystems and their functions, Enhancing sustainable urbanisation, Sustainable development of coastal regions

Client:

City of Medmerry

Design team:

the UK Environment Agency

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