Coastal Squeeze and Rollback

It is generally accepted that sea-levels are rising in Britain, although there are many opinions about the causes and the rates. Most scientists believe that the rate of sea-level rise has already accelerated and will continue to do so until levels of atmospheric carbon-dioxide start to be reduced.

Regardless of the cause or rate of sea-level rise the effects are the same, in a natural system land is “lost” and becomes sea. With a high coastline this manifests itself as erosion of the cliffs, but with a gently rising coastline the result is a slow movement of the shoreline inland – so over time a particular piece of land will change from dry land to shoreline shingle or mud, then foreshore and eventually to sea. The rate of change will depend on sea-level rise, but also on how “dynamic” the environment – how exposed it is to tide and waves.

In the case of a defended coastline if defences are maintained and increased to take into account the sea-level rise (Hold the Line in SMP’s etc) this results in the seaward side of the defence continuing to develop naturally – ie change from foreshore to sea, but the landward side remains the same. The result, known as “Coastal Squeeze” is that the foreshore (Sand, shingle or salt-marsh) is slowly lost together with the natural transition zone from land to sea.

The habitats of these ephemeral transition zones are both rare and important and as a result many are designated under international, European and National designations which require them to be protected.

We are very fortunate locally as the New Forest Coastline contains some of few areas where there is natural gently rising coastline. This is rare, particularly in Southern England, where most of coastline is heavily managed and defended to provide flood and erosion protection. These areas show a natural graduation from farmland, often to a narrow strip of woodland, then to a foreshore, often with the remains of fallen trees, to foreshore and salt-marsh.

The narrow strip of woodland provides a unique habitat, and the tree-roots will slow, and control the rate erosion. The fallen trees also provide a unique habitat and make the shoreline interesting and very different from most other places.

Within the Solent Protection Society we believe that these unique habitats should be maintained, by natural processes, and that they cannot be maintained by traditional engineering works. The most effective way to maintain the habitat is to allow natural roll-back. This should be done by allowing natural regeneration of indigenous vegetation, particularly woodland, along a margin between farmland and the coastal strip.

We would welcome members opinion of how these habitats should be managed and whether this should be funded by public authorities, or whether the landowner should be expected to manage appropriately.

Langstone Sea Defences

SPS was made aware of concerns regarding the imminent preach of the sea defences and lack of action at Southmore Lane, Langstone.

Havant BC had released a press notice last week announcing £376,000 funding had been secured for options appraisal for coastal defence study at Langstone because of flood risk for 86 homes and Hayling Bridge. It has been agreed by the SPS Couincil that a member would join the Eastern Solent Coastal Partnership stakeholder working group and will monitor activities.

As part of this activity, we will take note of any potential impact on the National Coast path.

City of Portsmouth – Flood Defences

Proposals for new sea defences for the island city of Portsmouth are gaining increasing visibility among local residents, with two seemingly opposing views both now being publicly debated.  This work is in response to the Environment Agency Flood Risk Assessment, which predicts the sea level rising by up to 1.2 metres within the next one hundred years.  The “Old Portsmouth and GunWharf” Neighbourhood Forum meeting last night was treated to presentations by the Eastern Solent Coastal Partnership and Portsmouth University School of Architecture lead Walter Mendeth on their respective proposals for improved flood defences for Portsea Island.  It was clear from the reaction of more than one hundred residents present that this essential program of work on the North Solent shore will attract high profile and high quality debate in coming years.  The SECP spokesman gave a comprehensive presentation on the process being followed by the organisations concerned, essential for the securing of appropriate central government funding of a ‘Hold the Line’ approach, while Walter Mendeth offered a more visionary, but as yet un-costed solution to this significant requirement for Portsmouth.


Solent Protection Society are watching these proposals with keen interest and would support a collaborative approach to the evolving design. While the ‘Hold the Line’ approach provides the essential backbone to a program of work which will attract the essential government funding, the lateral thinking introduced by the broad academic team which made up the ‘Elephant Cage’ project will inject an element of flair into the upcoming design stages which could give the final outcome the global appeal which it surely deserves.

Recognising the importance of Portsmouth as the United Kingdom’s only island city puts it on the same level as a small but historically significant island cities built worldwide from which significant maritime history has evolved. Placing Portsmouth on the same level as Venice may appear to be stretching the point, but we believe that it is critical that the plans for the city’s sea defences pay due regard to its heritage.

The new IPCC report.

The new report from the International Panel on Climate Change substantially confirms previous findings. Full details are available here. You can read the summary here.There is no disagreement among the authors about the confidence of the predictions.

Only one dissenting author expressed disappointment at the lack of emphasis on mitigation and adaptation. There is no doubt that action at government level to reduce emissions needs to be vigorously encouraged, but we will have to learn to cope with significant climate change impacts already built into the system.. But that is at a global and international level. Locally we need to think what  can be done to alleviate the effects of flooding, prolonged drought and potential changes in weather patterns.

For the first time, the IPCC have clearly acknowledged that in addition to vigorous measures to reduce the effect of emissions on the climate, there is already so much change built nto the climate system that we are going to have to learn to adapt to inevitable changes at some level. The SPS Council will be considering the report when the promised third part of its review is published. This part should cover ,inter alia, the action that the IPCC believes is necessary to adapt to climate change. Such action is likely to have implications for the Solent and could eventually become the subject of legislation

In the Solent we are already seeing changes that maybe attributable to changes in weather patterns. It is not good enough to simply allow changing weather to wipe out important features such as the saltmarsh areas of the West Solent and Portsmouth Harbour. Already we are seeing rapid declines in some Solent bird populations. compensation projects such as Medmerry are welcome, but not enough on their own.

Protection of the environment needs to have a human context.

Having conveniently ignored sound science for the past sixty years, we are sadly now only able to address ‘damage limitation’  (adaptation and mitigation) rather than ‘damage avoidance’ (prevention).  However while there are many other coastal areas of the world far more fragile than the Solent, that does not mean we should continue to ignore the topic –  it won’t go away and will become increasingly critical.


Can we create saltmarsh?

Hannah Mossman’s presentation to the SPS Council and invited guests on 3rd March bubbled with enthusiasm for the subject, and clear technical understanding.It was yet another step in the efforts of SPS to understand the issues arising from saltmarsh loss in the Solent. This interest was focussed in a conference that SPS organised in 2008. (click  here to view the conference proceedings)

Hannah Mossman
Hannah Mossman

Many of us have heard of grand coastal realignment schemes such as that £25 million project at Medmerry near Selsey. Such things are way beyond the scope of small charities such as SPS. But Hannah’s efforts to improve the quality of newly created saltmarsh were on a much more modest scale-but no less important. She is trying to re create the conditions in which marsh flowers can thrive so that the new saltmarsh can reproduce that which is being lost to coastal squeeze.

It was fascinating, and may even have shown a way in which local people con collaborate to help get the best from Coastal projects.

The slideshow from Hannah’s presentation can be viewed by clicking here.

MCZ tranche 2 update

The RYA have published details of a DEFRA announcement of the next tranche of MCZs to be investigated. We agree with RYA that the decision to include the management measures in the consultation process is to be welcomed.

Sites at Bembvidge; Norris to Ryde ( Osborne Bay); Yarmouth to Cowes; and the Needles are all included in this tranche. Although not in the Solent, the proposed MCZ at Studland is of particular interest because it has already been the subject of research that may give a guide to the management measures that could be applied to the Solent MCZ sites.

The designations are due to be determined by 2015. Full details of the process, and the list of the 37 sites to be reviewed is included in the RYA announcement

Habitat Creation Conference presentation downloads available

The presentations given at the ABP Mer Conference in November (and the formal proceedings) are now available for download via Linked In. The conference report is available from the Resources section of this website (go to Proceedings where SPS is a sponsor or participant)

The conference, for which Solent Protection Society was one of the sponsors was titled “Habitat Creation: Are we Delivering?”. It was aimed at environmental professionals and reviewed a number of recent and current habitat creation projects. A full report of the conference has already been published as a blog item .
Solent Protection Society has arranged a follow up meeting to be held in Lymington on 20th February.There has been growing concern about the rapid erosion of saltmarsh in the West Solent, compounded by the alleged effect of the new larger ferries. Several compensatory projects have been undertaken in the area, and ABP Mer have been involved in several of them. So it is singularly appropriate that Colin Scott from ABP Mer will be delivering this, the third in the SPS series of Winter lectures.

For more information, and to book, click here


Work to Start at East Head

This is a good news story about cooperation between the voluntary sector and government agencies. Steps have been agreed which will be carried out to reduce the risk of a breach of the delicate part of the sand spit known as The Hinge at East Head, at the mouth of Chichester Harbour.

At a time when our coasts are being battered by severe weather, it is pleasing to see a positive story.


Habitat Creation – Are we delivering – feedback

What a good day it was! We were delighted to have been a sponsor.

The conference programme was balanced and sought to draw out, the experience, the problems, and the way forward. You can read the conference report by clicking here. All the conference presentations are available by clicking here.

Our hope is that our intervention in the discussion will lead to a serious re-appraisal of the beneficial use of dredged material arising from the major dredge of Southampton Water being undertaken by ABP. As things stand, some 3 million cubic metres of materials will be wasted by being dumped at the Nab. That cannot the best solution!