Ventnor Coastal Protection and Slope Stabilisation Scheme Information Page

Closes 29 Sep 2028

Opened 27 Jan 2022


Ventnor undercliff

Ventnor undercliff – Ventnor town has been developed on terraces created by relic landslides

Welcome to the Ventnor Coastal Protection and Slope Stabilisation Scheme Information Page.

The Environment Agency have created this page to provide easy access to information on the Ventnor project, one of four priority coastal defence projects on the Isle of Wight. The Environment Agency will be updating this site as the project progresses, so please keep checking for what's new.

If you would like to be added to our mailing list to receive updates on this project or any other of the Isle of Wight coastal defence projects, please email us and let us know which projects you are interested in. Our email address is:

Our latest newsletter can be found here

For information about other coastal defence projects on the Isle of Wight see here.

Latest Updates

7 December 2023

7 December


The esplanade between Wheelers Bay and Bonchurch will remain open until Mid-January.

Core samples

Concrete samples, taken from Wheelers Bay esplanade, are undergoing laboratory testing. Additionally, CCTV and laser scans undertaken beneath the esplanade will inform where and how we can go forward in the next phase of works.

Trail pits and Boreholes

Our first consideration must always be to minimise the danger to all, especially when the investigations will be undertaken in a constrained and exposed location over the winter period.

Therefore a decision has been taken to  reduce the number, extent and scope of the boreholes due the significant risk associated with undertaking mitigation works ahead of drilling individual boreholes. The risk management works, in the form of stripping back the esplanade and slowly digging down five metres in each proposed borehole location, was deemed necessary due to the presence of a Southern sewerage main and potentially other unmarked services embedded within the esplanade.   

Intrusive investigation of the defences, fronting the Bonchurch Cliffs,  will potentially take place later on the scheme development, dependent upon the results derived from the trial dewatering scheme, being undertaken above Ventnor’s Western Cliffs.  

We will now focus our efforts in the vicinity of Wheelers Bay, where the coastal defences are in poorer condition.

Trial dewatering borehole

Phase 1: Above Western Cliffs 

Four of the seven monitoring boreholes have now been successfully drilled. However, the rate of drilling has been significantly slower than forecast due to the presence of sizeable boulders. Ground water samples,  taken from the constrained aquifer thirty-five meters below sea level, have shown slightly above average iron content and more siltation than anticipated.  

Additionally,  the initial results indicate the aquifer is heavily fractured, thereby limiting the area of effectiveness of an individual extraction wells. These finding will be used to inform the design and equipment to be used during Phase 2, the trial ground water extraction tests. Ground water levels and landslide movement, within the immediate area of the trial dewatering borehole, will be monitored throughout during this second phase.

Whilst the ground investigations are taking place, we will update our website on a weekly basis so that you are always aware of our most up to date programme. The dates may well change, either because of the information collected or because of adverse weather.


The next update will be published here on 14th December 2023.

April 2023

Ground penetrating radar surveys (GPR Surveys)

GPR surveys are a non-intrusive investigation approach to understand the sea defence dimensions, voiding and location of services within the defences. This is useful information that will inform the next phase of investigative works which is broadly known as Ground Investigations. Unfortunately, the GPR results were inconclusive, as is often the case when surveying reinforced concrete due to the presence of steel which disrupts the radar.

September 2022

Visual Asset Inspection

To assess the quality of the Ventnor Coastal defences and how they will react to sea rise, a specialist has observed and assessed them. This information will now be used to prioritise works and where to target further investigations.

The asset inspection looked for signs of deterioration, assigning a grading from 1 (very good) to 5 (very poor/failed). The grading estimates the assets remaining ‘useful’ life. For example,  how long until refurbishment and/or replacement of the asset is required. As part of this assessment, climate change projections such as sea level rise and increased storminess and rainfall totals are all considered. The information will help target further investigations and inform the sequence in which works are undertaken.  

August 2022

Topographic Survey of the land and coastal defences between Steephill Cove and Monks Bay

Topographic Survey of the land and coastal defences between Steephill Cove and Monks Bay.

A topographic survey is an accurate depiction of a site that shows the natural and man-made features and their levels. It is done by land surveyors using specialised equipment and skills. 

The aim of the topographic survey is to gain a better insight into how the landscape will interact with any investigative works and identify problems before works commence.

Property Level Threshold Survey

In addition to the topography survey, property level threshold surveys have been completed. This is a process that assesses the level of flood risk to a property or site based on the critical water level entry points of the property. It is required for some developments located within flood zones.

The pictures below show Property Level Thresholds being assessed in Ventnor



The Environment Agency in partnership with the Isle of Wight Council, with expert support from JBA Consulting and VolkerStevin, are exploring a sustainable future for the coastal frontages of Ventnor and Bonchurch, located on the south eastern coast of the Isle of Wight.

Ventnor Coastal Protection and Slope Stabilisation Scheme. Site location map. Credit: OS © Crown copyright (2021)

Ventnor and surrounding villages are located on ‘the Undercliff’, a large deep seated coastal landslide complex, initiated by sea level rise at the end of the last ice age (approximately 10,000 ago). It is one of the largest urbanised landslide complex in north-west Europe. As a result of the underlying geology, topography, coastal erosion and seasonal fluctuations in groundwater levels, historical landslide movements range from continuous small scale creep to less frequent, larger scale events which have caused significant damage.

Cross section through the landslide complex at Ventnor park

Cross section through the landslide complex at Ventnor Park showing multiple landslip blocks

More Information

Coastlines are naturally dynamic environments, where erosion and change is a common occurrence. To reduce risks to people, property, infrastructure, environmental habitats and the species they support, coastal erosion risk management requires a careful and holistic approach, especially in this area of potential landslide reactivation such as the Undercliff.

In the past, seawalls have protected the steepest and most developed parts of the town from toe erosion and have reduced risks, but in the face of accelerated climate changes (sea level rise and increasing winter rainfall), how will these risks be best managed in the future?

More Information

Some sections of the coastal defences are in a good condition, and are expected to offer sufficient protection for many years to come, whilst other sections are in need of repair. Areas of the coastal defences which are in poor condition leave them susceptible to significant failure within 10 years. Loss of the defences would result in coastal erosion at the base of the landslide complex, potentially increasing the risk of landslide reactivation. It is therefore proposed to replace sections of the existing coastal defences as part of the scheme.

Whilst the main cause of landslide reactivation is coastal erosion, the defences themselves remain vulnerable to damage from land movement driven by seasonal groundwater fluctuations. This risk is expected to increase due to the impacts of climate change. Management of groundwater levels, via deep drainage wells, will be explored at the next stage of the scheme's development.

More Information

The Environment Agency, on behalf of the UK government, prioritises and allocates funding to flood and coastal erosion risk management schemes using a partnership funding approach. Securing national funding is dependent on the scale of benefits and outcomes delivered by a scheme and, if required, funding contributions may be from other sources such as local levy (raised by the Regional Flood and Coastal Committees), private or public organisations.

More partnership funding details can be found here.

Current estimates suggest the Ventnor scheme would be eligible for circa £41 million of Flood and Coastal Erosion Risk Management Grant in Aid funding. However, scheme costs, benefits and potential contributions are very much dependent upon further investigations.

More Information

No decisions have yet been made about how best to address erosion risks in this area. Since September 2020 the Environment Agency have been gathering information and putting a case together for public investment in flood and coastal risk management infrastructure improvements. The Environment Agency submitted a high level business case (a ‘Strategic Outline Case’) to its internal assurance group in August 2021. Approval, received in November 2021, justifies funding for the next stage of business case development (Outline Business Case).

The ‘Outline Business Case’ stage began in 2022 and is still ongoing. The scheme is proposed to be developed over approximately 6 years. This will allow options for improving the defences and managing groundwater levels and their implications to be more fully explored.  This will include on site investigations and assessing seasonal changes.

More Information

The project is still in its early stages and the Environment Agency have identified a wide range of options to reduce the existing risk of landslide activity. The Environment Agency will, however, need your thoughts and ideas to supplement its technical assessments, to develop these options. This will take time, but the Environment Agency will increase its engagement activities in the coming months as it introduces the project, shares initial findings, and gathers views on what is valued about the coastline as well as any concerns about its future. Throughout this project there will be numerous opportunities for you to feed into its development and would encourage you to do so.

Frequently asked questions can be viewed here

Further information about current and future coastal risks at the Ventnor Undercliff area can be accessed here at the Isle of Wight Council website

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By phone: 03708 506 506


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