Medmerry Case Study Coastal Realignment

Medmerry, West Sussex, on the south coast of England, is Europe’s largest coastal realignment scheme.

Medmerry Coastal Realignment

Why was the Medmerry coastal realignment scheme needed?

Medmerry had long faced problems with flooding from the sea, with regular breaches of the shingle bank, most recently in 2008, when over £5m of damage was caused. Several hundred thousand pounds were spent repairing and maintaining the shingle bank every year. Without annual maintenance, 348 properties in Selsey, a water treatment plant and the main road between Chichester and Selsey would be flooded, along with many holiday homes and rental cottages. The last time the sea breached the shingle bank in 2008, it caused damage totalling £5 million.

What is the Medmerry coastal realignment scheme?

Medmerry is the largest managed realignment of the open coast in Europe, and the first in the UK, on the stretch of the southeast coast most threatened by coastal flooding. The scheme has created an intertidal habitat, replacing vital areas lost in the Solent, allowing new defences to be built and protecting thousands more properties along the coastline.

The scheme is recognised locally, nationally and internationally as an exemplar scheme and is one of the most sustainable projects the Environment Agency has delivered.

Aerial view of the Medmerry Coastal Realignment Scheme – Image: Environment Agency

Work began on the Medmerry Coastal Realignment Scheme in 2011 following a public consultation. It was completed in 2014. The project was achieved by:

Constructing a new 7km embankment using clay from within the area. The embankment created a new intertidal zone, protecting properties behind it from coastal flooding.
A channel was built behind the embankment to collect draining water. This water is taken back into the intertidal zone via four outfall structures.
Sixty thousand tonnes of rock from Norway was used to build up rock armour on the seaward edges of the embankment, linking to the remaining ridge.
Once the rock amour and embankment were complete, a 110-metre breach was made in the shingle bank on the beach, allowing the sea to flood the land and creating the new intertidal zone.

What are the positive effects of the Medmerry Coastal Realignment Scheme?

What are the social benefits of the Medmerry Coastal Realignment Scheme?

Selsey now has the best protection from coastal flooding, with only a 1 in 1000 chance of coastal flooding. 348 properties and sewage works are now protected to a standard of 1 in 100 years (previously just 1 in 1 year). The scheme avoided a possible breach during severe winter storms in 2013.
The area now has ten kilometres of footpaths, seven kilometres of bike paths, and five kilometres of bridleways compared to the previous two small footpaths before the scheme was developed.

What are the economic benefits of the Medmerry Coastal Realignment Scheme?

Caravan parks and Selsey’s main road route are now protected to a standard of 1 in 100 years (previously just 1 in 1 year).
The local economy has received a boost from an increase in green tourism, and the caravan parks have been able to extend their season, generating income and jobs. Two new car parks and four viewing points give easy access.
Vegetation on the salt marsh supports extensive cattle farming, producing expensive salt-marsh beef.

What are the environmental benefits of the Medmerry Coastal Realignment Scheme?

The site contains 300 hectares of habitat of principal importance under the UK Biodiversity Action Plan, including mudflats, reed beds, saline lagoons and grassland. This includes 183 hectares of newly created intertidal habitat important to wildlife on an international level. It is crucial in compensating for losses due to development around The Solent, allowing the region to meet its European directive targets. Birds and other new wildlife appeared at the site long before completion.
The area is now a huge nature reserve managed by the RSPB.

What issues and conflicts resulted from the Medmerry coastal realignment scheme?

What are the social issues of the Medmerry Coastal Realignment Scheme?

Some residents feel that the Environmental Agency should have explored other options, such as an offshore reef or continued beach realignment, and not have given up on the land so easily.
Some opponents from outside the area resented a significant sum of money being spent on a scheme in such a sparsely populated area.

What are the economic issues of the Medmerry Coastal Realignment Scheme?

The project was expensive at £28 million compared to £0.2 million a year to maintain the shingle wall. Though with rising sea levels, this can be challenged quite easily.
Good agricultural land was abandoned, leading to the loss of three farms growing winter wheat and oilseed rape.

What are the environmental issues of the Medmerry Coastal Realignment Scheme?