COASTAL DEFENCE SCHEMES

Below is a list of some of the more recent and most studied of the coastal defences built on the Island. Just click on the dots on the map to jump to the information relating to the scheme.

Information updated 2013.

St Helens Duver, 2012
The Isle of Wight undertook significant repairs to the seawall at St Helens Duver, Bembridge Harbour, in spring 2012. Please click here for full information about the works.

The completed St Helens Duver repairs

Seaview Coastal Defence Scheme
A £4.7 million coast protection scheme for the Seaview Duver frontage between Oakhill Road and Springvale was completed in April 2004. Constructed over a period of one year by Van Oord ACZ the project was commissioned by the Isle of Wight Council's Centre for the Coastal Environment and designed by its consulting engineers, Royal Haskoning. The scheme was grant-aided by the Department for Environment, Food and Rural Affairs (Defra).

The scheme is providing the required standard of protection against coastal erosion and sea flooding for at least the next fifty years taking full account of the predicted impacts of climate change. The scheme comprises a 550m length of stone-faced reinforced concrete seawall protected on the seaward side by a rock armourstone revetment.


The Completed Seaview Duver Scheme

Additional facilities include an upgraded slipway and pedestrian walkways on the seaward and landward sides of the wall together with seating. In order to maximise the appearance of the final scheme the Council appointed John Maine RA, a sculptor and artist, to contribute to the aesthetic qualities of the design.

The foreshore and intertidal area along this part of the Seaview coast is designated as a Special Protection Area under the European Birds Directive. In order to mitigate any impacts arising from the civil engineering works on this European site the Council has acquired, for a peppercorn rent for the next fifty years, 20 acres of marshland and reedbeds on the landward side of the former toll road from the Ball family. With the assistance of English Nature, the Environment Agency, local residents and environmental specialist consultants ECOSA a nature reserve has been developed which includes public access and the provision of a hide for bird watching. The area has been improved in order to maximise the environmental quality, particularly for wading birds, ducks and geese. The nature reserve has been named after Alan Hersey, who was for many years a Parish, Borough and County Councillor who had a great interest in the history and environment of the village of Seaview. A formal opening of the coast protection scheme by HRH The Duke of Edinburgh took place in August 2004. The scheme was awarded a special prize by the Isle of Wight Society for the quality of the conservation and landscaping work. In addition the scheme was awarded the New Civil Engineer/Association of Consulting Engineers 'Outstanding achievement award' in 2005.

Seagrove Bay Coast Protection Phase 2, Seaview
As a result of the extremely wet winter of 2000/01, when widespread landsliding occurred around the Isle of Wight coastline, the coastal slope along the frontage between the slipway at Seagrove Bay and the village was subject to varying degrees of slope reactivation. This had an impact on some of the properties in the vicinity. In consultation with the Council the residents employed a geotechnical consulting engineer to offer advice on stabilisation measures. At the same time this part of the Isle of Wight coastal frontage had been affected by a long period of easterly winds, which have led to depletion of the beach on this frontage in Seagrove Bay. This raised concerns about the stability of the seawall, and its future, as parts of the foundations were becoming exposed. The Council also commissioned a geotechnical survey of the foreshore to assess the overall slope stability situation.

In consultation with resident frontagers the Council has developed proposals for a coastal protection scheme along this part of Seagrove Bay, which would provide the necessary protection for the frontage for at least the next fifty years.

Following initial consult22 March, 2013the Environment Agency, scheme options were developed and these were the subject of consultation during the early summer of 2005. Proposals must be technically sound, environmentally acceptable and economically justifiable in cost benefit terms. Planning consent for the preferred scheme option has now been received and it is anticipated that a submission for a coast protection grant will be made to Defra during 2007.

Bembridge Frontage
The possibility of improved coastal defences along the Bembridge frontage between the Bembridge Coast Hotel and Bembridge Point has been under consideration for several years. Following completion of a comprehensive coastal defence strategy study of the Island's north-east coast the preferred policy for this frontage is slow down the rate of coastal erosion. Investigations are centring on the proposal for a beach recycling plan for the frontage, which would allow the foreshore to be recharged with shingle in order to provide protection to the cliffs, walls and properties located behind.

A range of technical and environmental studies have been undertaken and these have been discussed with the statutory consultees. The scheme will be subject of an application to the Department for Environment, Food and Rural Affairs (Defra) for coast protection grant.

Shanklin/Sandown Cliff Management
Sandown Bay is backed by 3.5km length of weak sandstone cliffs between Shanklin and Sandown on the Southeast coast of the Isle of Wight. These cliffs lie within a major tourist area and have a history of cliff falls. Cliff top recession, although relatively slow, has placed some cliff top paths at risk as well as structures in areas of public access and amenity. Furthermore the debris from rockfalls and cliff face erosion has presented a potential risk to the seafront amenities adjacent to the cliff base.

A study by the Council was carried out in order to provide data for decisions regarding the management of the area. This provided the basis for assessment of the hazard and risk along the cliff line and outline some of the remedial techniques that are being adopted to address specific prioritized areas. A more detailed explanation of this site and the approaches to cliff management is available from the Coastal Visitors Centre. Further works on cliff stabilisation in Sandown Bay, particularly at Shanklin, took place in Spring 2006.

Monk's Bay, Bonchurch
The area of Monk's Bay has long been subjected to aggressive marine erosion causing the coastal slope to become inherently unstable. Following the wet winter and severe storms of 1990/91 a scheme was developed to defend the area. It involved using a rock armoured revetment against the existing seawalls on the Western frontage together with an offshore breakwater and beach nourishment scheme protecting the Eastern half. The material used was Norwegian granite. 25,000 tonnes were imported along with 40,000 cubic metres of sand and shingle. This scheme cost in the region of £1.4 million.

Wheeler's Bay, Ventnor
Wheelers Bay forms part of the toe of the Ventnor Undercliff Landslide Complex. A study by the former Department of Environment (1988-91)highlighted the maintenance and improvement of coastal defences as a key strategic task in reducing the impact of landsliding on the local community. Ground movements within the slope behind Wheelers Bay showed there was significant risk to the existing seawall and property and infrastructure upslope. The solution consisted of moving the coastal defences seaward and reconstruction of the slope to a shallower profile. The new protection comprises a 15,500 tonne revetment with an outer layer of 6-10 tonnes of rocks. 23,000 tonnes of locally obtained chalk was used as fill material to provide a stable slope behind the revetment. The upper slope was strengthened with soil nails and grass matting. The total cost of the scheme was £1.6 million.

Ventnor Eastern Esplanade to Wheeler's Bay Coast Protection
The coastal frontage between Ventnor Eastern Esplanade and Wheeler's Bay is the only section of the defended Undercliff coast that has not benefited from improvements to coastal defences over the last fifteen years. The existing concrete wall, which is sheet-piled to its face along part of the frontage and protected by concrete tetrapods on the eastern part, has been subject to aggressive marine erosion, weathering and the impacts of slope movement from behind. The area lies within the Ventnor Undercliff landslide complex where slope movements are to be expected from time to time, however, the impact of slope movements including the passage of ground water has led to a significant deterioration on part of the existing structure.

In 2006, the Centre for the Coastal Environment investigated opportunities for attracting coast protection grant-aid for this frontage in order to provide a suitable standard of defence for at least the next 100 years. Work on this scheme is at a preliminary stage and the results of the investigations will be reported in due course.

An important consideration is that the frontage abuts the South Wight Maritime Special Area of Conservation, which designates the foreshore and intertidal habitats on account of the importance of the reefs and marine life. Any scheme must be technically sound, environmentally acceptable particularly in this respect and economically justifiable.

Western Cliffs, Ventnor
Storm Damage in 1990 resulted in aggressive marine erosion of the Western Cliffs in Ventnor which are made up of loosely consolidated chalk debris deposited at the end of the last Ice Age. If the erosion had continued unchecked there was significant risk that it would activate the ancient landslide complex behind it. It was decided to protect the base of the cliffs from erosion by providing a rock revetment of Somerset limestone which was brought in by barge. This scheme cost £1.2 million.

Castle Cove, Steephill, near Ventnor
Storm damage in the winter of 1990 resulting in the destruction of a wooden crib-work structure at the base of the slope at Castle Cove. The wet weather also prompted the slope to fail and it was decided that a scheme would be implemented to protect the area from any further erosion. The slope itself was drained and a section of topsoil removed for storage to be returned on completion of the scheme, as the area was regarded as of high nature conservation interest. A rock revetment was then built allowing vehicular and pedestrianaccess to Steephill Cove for the first time. The scheme was completed in 1995 when the topsoil was restored. Recolonisation has been slow but the site already shows considerable entomorphological and botanical interest.

Steephill Cove, near Ventnor, Coast Protection
Steephill Cove is a small bay situated approximately 2km to the west of Ventnor and is backed by residential development. The Victorian defences were partially upgraded when the Council was undertaking adjacent works on the Ventnor Western Cliffs in 1992/93. At that time it was recognised that further work may be required to the wall in the centre of the bay in years to come.

A modest project (£315,000) was approved by the Department for Environment, Food and Rural Affairs (Defra), with work being completed in summer 2006.

Castlehaven Coast Protection Scheme
Following the exceptionally wet winter of 1994 and the resulting landsliding along many parts of the Isle of Wight coast the Council started to develop a major coast protection and slope stability improvement scheme for the Castlehaven frontage at Reeth Bay to the east of St Catherine's Point, Niton Undercliff. A £6.2 million coast protection and slope improvement scheme was completed in 2004. The scheme was commissioned by the Isle of Wight Council's Centre for the Coastal Environment and was constructed by Van Oord Construction ACZ with support from drainage sub-contractors TJ Brent and specialist drainage engineers Groupe RESS from France.

The scheme comprised the construction of a 550m long rock revetment on the foreshore at Reeth Bay which will prevent erosion of the sea cliff. An extensive system of drainage pipes and syphon drains was provided in roadways in the hinterland in order to reduce ground water levels to the summer mean. For the first time in the United Kingdom a system of syphon drains is being used in order to lower ground water levels. Tested at over 100 sites elsewhere in Europe this system has proved successful in reducing ground instability by de-watering landslides of this kind.

The coastal cliffs along this part of the Undercliff are of particular importance as a habitat for species of insects including rare bees and wasps. In order to mitigate any impacts arising from the civil engineering scheme the Council has acquired 20 acres of rough pasture land along the cliff edge in the vicinity of Puckaster Farm as environmental mitigation for the scheme. A management plan for the area has been prepared by the Council's environmental consultants, ECOSA, and a programme of environmental monitoring is ongoing.

The project has been grant-aided by the Department for Environment, Food and Rural Affairs (Defra).

Blackgang
In January 1994 the impact of coastal erosion and high rainfall resulted in further extensive landslide activity on the 170m high cliffs at Blackgang a rea. These movements undermined several houses at the top of the cliff. The initial emergency response was to ensure public safety and security of the area which was co-ordinated by the Council. Further to this the Council commissioned a geomorphological investigation to identify the extent, causes and potential for further landsliding or slope movements. The study also identified a range of options for managing the problems at Blackgang, which included the installation of an early warning system and retreat ofdevelopment.

The land behind the cliff top is largely developed including a major theme park. In the absence of a financially and environmentally acceptable slope stabilisation and coast protection scheme, the policy of managed retreat of clifftop development and landuse is the only viable option (Clark et al 1996).

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Updated: 22 March, 2013