Future proofing our dynamic coast requires an appropriate buffer zone

The winter storms of the first weeks of 2018 brought into sharp focus how dynamic our coastline is. However, it also raised the spectre of how vulnerable many communities in the South West of England are to coastal flooding and erosion.

The formation of impressive dune cliffs at Crantock, the erosion of beaches at Bude and Perranporth, cliff falls on The Lizard and other locations, the destruction of coastal infrastructure at Portreath, and coastal flooding at many locations was all too familiar, especially for those with good memories of the havoc wreaked during the 2013/14 winter.

Coastal erosion and flooding, and consequent damage to infrastructure, disruption of services and modifications to the coastal landscape will become more common over the next century due to climate change. Rising sea levels will increase the probability of extreme coastal water levels and this could be exacerbated by potentially larger and more frequent extreme waves due to changes to the wave climate.

Much of our coastline in the South West of England is already eroding, as testified by the dominance of coastal cliff scenery. At the same time, our coastal zone is far from natural with numerous clifftop properties and extensive development at the back of beaches, on top of dunes and in low-lying coastal valleys. It is obvious, therefore, that coastal communities are facing significant future challenges.

Much existing coastal development took place when our understanding of coastal dynamics was limited and when climate change, and its consequences for the coast, was not yet a reality. That development is already under threat, and the scale of the threat will only increase in the future.

Dealing with this issue requires a balanced consideration of the various adaptation strategies, ranging from ‘hard’ coastal protection such as sea walls, to more sustainable solutions such as supplementing the amount of sand on our beaches and even managed realignment.

If we wish to avoid piling ever-increasing costs – in both financial and environmental terms – on future generations, we should avoid more development in the dynamic coastal zone unless it is absolutely essential. But while that might seem a largely sensible notion, how can it be implemented?

A new planning instrument is already available to help decide where coastal development may not be appropriate. The National Planning Policy Framework (NPPF) requires councils to identify Coastal Change Management Areas (CCMAs), where necessary.

A CCMA is defined as 'an area identified in Local Plans as likely to be affected by coastal change (physical change to the coastline through erosion, coastal land slip, permanent inundation or coastal accretion'.

The landward limit of CCMAs represents the estimated 100-year erosion line with an additional buffer of ten metres. It is based upon analysis of shoreline trends and an upward adjustment based on the anticipated acceleration in the rate of sea-level rise.

This policy is now in the process of being rolled out across the South West, with the Newquay Neighbourhood Plan, which is currently under consultation, using the CCMA to suggest some sensible planning policy advice.

For example, it states that proposals for development in the CCMA should only be supported where they are for 'small, temporary structures that will not add to the erosion risk'. That rules out residential development. 

Proposals for redevelopment, enlargement or extension of existing buildings that fall within the exclusion zone, and proposals to change the use of existing buildings into residential usage, will not be supported either.

In order to future proof our dynamic coast, we need to implement an appropriate buffer zone, along the lines of the CCMA plans, to inform coastal planning decisions. And it is vital that such sensible policy suggestions should be included in a legislative framework and taken into account when considering planning applications related to the development of our coastal zone.

Unfortunately, this does not seem to be happening at the moment as in Carbis Bay a number of two- and three-storey luxury apartments are currently being built on the beach. Meanwhile in Newquay, ahead of the Neighbourhood Plan coming into being, permissions have been granted for the development of new properties within ten metres of clifftops.

Our research has previously shown that the 2013/14 winter storms were the most energetic on record, and at Porthleven in Cornwall, 1,350 cubic metres of cliff face was eroded along a 300-metre stretch of coastline in just two weeks. Meanwhile at Torcross in Devon, the beach level was reduced to such a degree that the foundations of the sea wall were exposed.

With the impact of global warming and rising sea levels, there is every reason to suspect such incidents might become more frequent in years to come. To combat this threat, buffer zones will need to be site-specific and science-based, and would require regular updating in light of new data, understanding and predictions of climate change and its consequences.

We need to recognise that avoiding further development of the dynamic coastal zone will save us money in the end, whilst at the same time preserving the coastal landscape. Continued investment into the coastal zone will reduce its natural capability of the coast to response to hazards, whilst at the same time passing the financial burden of protecting such coastal development onto future generations.

Coastal Marine Applied Research (CMAR)

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