GEOLOGICAL FAILURE REPORT: RED ZONE 9 WOODLANDS

GEOLOGICAL

FAILURE REPORT

RED ZONE 9: WOODLANDS, UNDERCLIFF DRIVE

May 2014

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GEOLOGICAL FAILURE REPORT: RED ZONE 9 WOODLANDS

Title Geological Failure Report – Red Zone 9: Woodlands

Version Number 4

Document Status Final

Date of Next Review June 2014

Version Report Author Report Checked Report Approved

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Approved for Island Roads Services Limited Date Signed

GEOLOGICAL FAILURE REPORT: RED ZONE 9 WOODLANDS

Contents

1 INTRODUCTION ...... 1 2 CONTRACT RESPONSE……………………………………………………………………………………………………………….1

2.1 Contract Clause 12.1.1.1…………………………………………………………………………………………………1

2.2 Contract Clause 12.1.1.2…………………………………………………………………………………………………3

2.3 Contract Clause 12.1.1.3…………………………………………………………………………………………………4

2.4 Contract Clause 12.1.1.4…………………………………………………………………………………………………6

2.5 Contract Clause 12.1.1.5…………………………………………………………………………………………………6

2.6 Contract Clause 12.1.1.6…………………………………………………………………………………………………6

2.7 Contract Clause 12.1.2……………………………………………………………………………………………………7

APPENDICES……………………………………………………………………………………………………………………………………...i

Appendix 1: Ramboll Report – Woodlands Site 9, Undercliff Drive Geological Failure………….ii

Appendix 2: Drawing 1- Undercliff Landslip Diversion………………………………………………………….iv

Appendix 3: Drawing 2 – Extent of Ground Movement Along Undercliff Drive (2014 Event)..v

Appendix 4: Failure Costs and On-going costs……………………………………………………………………..vii

Appendix 5: Remediation Options and Approxiamte Costs………………………………………………….vi

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GEOLOGICAL FAILURE REPORT: RED ZONE 9 WOODLANDS

1 INTRODUCTION

A Geological Failure occurred at Red Risk Site 9 Woodlands on 10 th February 2014. A section of the road that has undergone movement previously has failed during the period of construction works to stabilise the road.

Clause 12.11.1 of the Highways PFI contract stipulates that Service Provider must provide a failure report detailing the nature and proposed costs of remediation, management and or rectification for each Amber or Red zone Geological Failure. This report follows on from the Failure Notice issued by the Service Provider to the Isle of Wight Council in March 2014. Below is a response to each of the clauses required within the contract. Details of the clauses within the contract are given in Table 1 of the Ramboll report in Appendix 1.

2 CONTRACT RESPONSE

2.1 Contract Clause 12.11.1.1

For details of the Geological Failure please refer to Appendix 1 Ramboll Geotechnical Report Sections 1 and 2 which provide updated and more detailed information of those matters contained in the original Failure Notice. An introduction is provided within Section 1 together with its location and also reference to construction activities that have occurred in the area. Under Section 2, information is provided on historical landslide behaviour together with findings from the inspection of the site undertaken on 10 th February 2014.

The main failure at Site 9 Woodlands occurred over 14/15 th February 2014 at the western end of the geotechnical construction scheme that was underway to stabilise the road. All excavations and construction of the ground anchor reaction beam were complete up to this point.

In addition to the information given in Appendix 1, a plan showing the extent of the ground movement caused by reactivation of the landslide along Undercliff Drive over January/February 2014 is shown in Appendix 3. The main line of the failure cuts across the completed ground beam (part of the geotechnical works), and behind it through the centre of the original carriageway along pre-existing cracks (Fig. 1a). The failure then cuts across into the garden and driveway of the property ‘Allenmore’ (Fig. 1b) and extends into the garden of ‘Mount Lavinia’. The line of failure can then be traced across this property to the south side of the Undercliff Glen Caravan Park. A separate new area of failure developed within the west bound side of the road immediately outside the property ‘Allenmore’ (Fig. 1c) and can be traced through the corner of the property and into the garden of the property ‘Mount Lavinia’.

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GEOLOGICAL FAILURE REPORT: RED ZONE 9 WOODLANDS

Figure 1a . Site 9 Woodlands Geological Failure. Location at which the failure cuts across the completed ground beam (red arrow).

Figure 1b . Site 9 Woodlands Geological Failure. Backscarp of the failure cutting across into the garden of Allenmore.

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GEOLOGICAL FAILURE REPORT: RED ZONE 9 WOODLANDS

Figure 1c . Site 9 Woodlands Geological Failure. New failure in the west bound carriageway outside the property Allenmore

Downslope of the site at Woodlands there have been metre scale movements indicated by the presence of large tension cracks, visible smooth slip surfaces and displaced vegetation. The area of movement has stretched downslope for more than 100m. A standpipe piezometer has also been destroyed through ground movement within this area of the landslide (located approx. 90m downslope of the geotechnical site).

2.2 Contract Clause 12.11.1.2

Within Appendix 1 Section 3 the implications of failure have been considered. Construction work was adversely affected from week commencing 10th February 2014 onwards. Movement continues to occur within the centre of the failure at Woodlands. Subsequent to the landslip at Woodlands, the site was made safe to the public.

Since gradual movement is still ongoing at Site 9 Woodlands the monitoring programme will be continued for the foreseeable future. Island Roads will continue to undertake weekly surveys and a CCTV system has been put in place to provide security for residents.

Groundwater levels remain high and therefore there remains a high risk that ground movements will continue. Movement continues to be detected within the area of failure at Woodlands and will continue to be monitored.

A full programme for rectification of the site has not been developed at this stage as it is dependent upon the length of time that groundwater levels remain high and there is still risk of ground instability. However a list of potential remediation options is given in

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GEOLOGICAL FAILURE REPORT: RED ZONE 9 WOODLANDS

Island Roads will continue to develop a scheme that considers the land instability further and will provide a more long term solution. Any solution will depend upon the actual recorded movement over the coming few months.

2.3 Contract Clause 12.11.1.3

Since the area is now impassable the area has been made safe by placing barriers at both the eastern and western ends with two sections of hoarding to prevent pedestrian access. Warning/danger signs have been attached to the outside of the hoarding and the access has been padlocked. Running adjacent to the hoarding is a section of Heras fencing in place to restrict access around the side of the hoarding. Three railway sleepers have also been placed outside the site with cones and a road closed sign. Inside the site the area has been completely cleared of all site cabins, construction equipment, vehicles and barriers. Photos of the current condition of the site are given in Fig. 2a, 2b and 2c.

Figure 2 a. Site 9 Woodlands Geological Failure. Hoarding, barriers and signs in place at the eastern extent of the site.

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GEOLOGICAL FAILURE REPORT: RED ZONE 9 WOODLANDS

Figure 2 b. Site 9 Woodlands Geological Failure. The current state of the site.

Figure 2 c. Site 9 Woodlands Geological Failure. Hoarding, barriers and signs in place at the western extent of the site.

A diversion has been set-up to direct traffic away from the area. Details for this diversion are given in Appendix 2.

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GEOLOGICAL FAILURE REPORT: RED ZONE 9 WOODLANDS

2.4 Contract Clause 12.11.1.4

Site inspections are undertaken regularly by Island Roads. Ground movement monitoring and groundwater level measurements are taken from existing instrumentation along the length of the site. The most recent surveys have shown that small scale movement is continuing. Further information on the current monitoring of the site is given in Ramboll Geotechnical Report Sections 2 and 4.

A number of recommendations for increased monitoring of the landslide were outlined by Ramboll in their March 2014 report (see Section 5 of Appendix 1 which includes the report updated to June 2014). The following were implemented by the Service Provider from January 2014:

• Increase inclinometer survey frequency to once per fortnight

• Monitor width of cracks and surface points in the road at Sites 8, 9 and 10 weekly

• Collect and carry out regular reviews of monitoring and rainfall data

• Review remediation proposals in view of revised ground conditions

• Once ground movement has ceased, the area seaward of the site will be re-surveyed

2.5 Contract Clause 12.11.1.5

Although final details concerning rectification of the Geological Failure cannot be produced until ground movement at the site has stopped as indicated by Ramboll Geotechnical Report Appendix 1 Section 6, a number of outline options are provided in Appendix 5 of this report and a brief description of each option is given in the main Geological Failure Report: Seven Sisters Road, St Lawrence to St Catherine’s Road, Niton

2.6 Contract Clause 12.11.1.6

Failure costs incurred to date and ongoing weekly costs associated with the failure are included within Appendix 3.

Since movement at the site is still on-going it is not yet possible to provide nor price a Proposed Failure Solution as referred to in Appendix 1 Sections 6 and 7. It is clear from the Ramboll Report that if the road is to remain in its current alignment then significant fill would be required to raise the road back to an acceptable alignment.

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GEOLOGICAL FAILURE REPORT: RED ZONE 9 WOODLANDS

2.7 Contract Clause 12.11.2

Resurfacing was due to be completed immediately after completion of the stabilisation works at Site 9 Woodlands. Seeing as the stabilisation works have not been completed due to the Geological Failure, the resurfacing works will not be completed until such time as a proposal for rectification is agreed and implemented.

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GEOLOGICAL FAILURE REPORT: RED ZONE 9 WOODLANDS

APPENDICES

i

GEOLOGICAL FAILURE REPORT: RED ZONE 9 WOODLANDS

APPENDIX 1: Ramboll Report – Woodlands Site 9, Undercliff Drive Geological Failure

ii

Intended for ISLAND ROADS

Document type REPORT

Date March 2014

ISLE OF WIGHT HIGHWAYS PFI WOODLANDS SITE 9 UNDERCLIFF DRIVE – GEOLOGICAL FAILURE

ISLE OF WIGHT HIGHWAYS PFI WOODLANDS SITE 9 UNDERCLIFF DRIVE GEOLOGICAL FAILURE REPORT

Revision 0 Date 2014/06/03 Made by Checked by Approved by Description Geological Failure Report

Ref 61030594-9-R02

Revision History

Revision Date Purpose / Document Ref. Comments Status

- 4.03.14 For Island 61030594-09-R02 Roads Review 1 4.06.14 For Island 61030594-09-R02 Incorporating Roads Review Island Roads comments

Prepared By Reviewed By Approved By

Ramboll Carlton House Ringwood Road Woodlands Southampton SO40 7HT United Kingdom

tel +44 (0)23 8081 7500 fax +44 (0) 23 8081 7600

WOODLANDS SITE 9 UNDERCLIFF DRIVE – GEOLOGICAL FAILURE REPORT

CONTENTS

1. INTRODUCTION 1 2. INITIAL OBSERVATIONS OF LANDSLIDE FAILURE/ BEHAVIOUR 2 2.1 Site Observations 2 2.2 Historical Landslide Behaviour 5 2.2.1 Ground instrumentation 7 2.3 Observations from Monitoring Data 9 2.4 Preliminary Stability Review 9 3. IMPLICATIONS OF FAILURE 10 4. INTERIM MEASURES 11 5. INFORMATION TO ASSESS EXTENT OF GEOLOGICAL FAILURE 11 6. ESTIMATE FOR TIME FRAME FOR GEOLOGICAL FAILURE RECTIFICATION 11 7. ESTIMATE OF FAILURE COST 12 8. REFERENCES 13

TABLES

Table 1 Summary of Failure Report Information ...... 2 Table 2 Summary of Landslide Forecast trigger values based on rainfall ...... 6

FIGURES

Figure 1 Location of Undercliff Drive Site 9 - Woodlands ...... 2 Figure 2 Summary of tension cracking observed on 10 and 13 February 2014 4 Figure 3 Extract of Geomorphology Map Site 9 and Site 10 ...... 5 Figure 4 Four Month Moving Average Rainfall and Landslide Events ...... 6 Figure 5 View of Site 9 taken on 12 March 2013 ...... 7 Figure 6 View of Site 9 taken on 24 July 2013 showing resurfacing carried out prior to contract award ...... 7 Figure 7 Monitoring locations, Undercliff Drive Site 9 - Woodlands ...... 8 Figure 8 Ground anchor beam monitoring points ...... 8

APPENDICES

APPENDIX A: Photographs APPENDIX B: Ground Monitoring Data APPENDIX C: Programme of completed actions

1. INTRODUCTION

Geological failure of Undercliff Site 9 – Woodlands was first reported on 10 February 2014. Site 9 is located at National Grid Reference 4525 0762 along Undercliff Drive, and is 218 metres long (Figure 1). This site lies immediately east of Undercliff Drive Site 10 – Caravan Park.

The existing road at Woodlands has been affected by repeated major land slippage some 90 metres from the western end of Site 9. Ground movement occurred in the winter 2012/13 prior to the award of the Highways PFI Contract. As a result of the 2012/13 ground movement Undercliff Site 9 was reprioritised, with work planned in the first year of the Highways PFI scheme. The highway was locally resurfaced prior to the commencement of the PFI Contract. The scheme was designed (July 2013) and construction works at this site had begun on 14 November 2013. Construction works had progressed to partial excavation of the existing carriageway, construction of the ground anchor beam and installation of eight ground anchors (unstressed). The east bound lane remained open. Construction photos are presented in Appendix A.

Following the initial notification the site was inspected by the Island Roads Geotechnical Engineer to map out the extent of surface cracking. In addition surface monitoring along the ground anchor beam and existing carriageway was initiated. A site inspection by the Ramboll Geotechnical Engineer was carried out on 13 February 2014 and 17 February 2014. The contract requires a Failure Report to include information as summarised in Table 1. This document summarises the proposed information and assessments required to assess the extent of Geological Failure.

Failure Report Text Reference in this Report Clause

12.11.1.1 Updated and more detailed information of those Section 1 and 2 matters contained in the Failure Notification and Failure Notice;

12.11.1.2 A full and detailed explanation of the impact of the Section 3 rectification, management and/or mitigation (as applicable) of the Red Zone Failure.

12.11.1.3 A full and detailed explanation of how the OpCo has See Island Roads report made the affected Project Network Parts and its surroundings safe to the public (including the remediation of all Category 1 Defects in accordance with the provisions of Schedule 2 ( Output Specification )).

12.11.1.4 A full and detailed explanation of what further Section 4 and 5 actions the OpCo is to undertake (including any inspections, tests, surveys and/or assessments in order to determine the full extent of the Red Zone Failure, Amber Zone Failure and/or Geological Failure);

12.11.1.5 A full and detailed explanation of how the OpCo Section 6 and 7 proposes to rectify, manage and/or mitigate (as appropriate) the Red Zone Failure, Amber Zone Failure and/or Geological Failure ( "Proposed Failure Solution" ) which shall, where the OpCo believes no action is required, provide a full explanation of the reasons for such belief, including any implications arising from taking no action.

12.11.1.6 An estimate of the total amount of Failure Costs See Island Roads report which the OpCo shall calculate acting reasonably (including all Failure Costs incurred up to the issue of the Failure Report) required to carry out the

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Proposed Failure Solution, together with documentary evidence such as full bills of quantity where practicable.

12.11.2 The OpCo shall at the same time as submitting the See Island Roads report Failure Report, amend and submit to the Service Provider pursuant to Schedule 20 ( Review Procedure ) any OpCo Programmes affected by the Proposed Failure Solution.

Table 1 Summary of Failure Report Information

Figure 1 Location of Undercliff Drive Site 9 - Woodlands

2. INITIAL OBSERVATIONS OF LANDSLIDE FAILURE/ BEHAVIOUR

2.1 Site Observations

The main points from the site inspections are summarised in this Section and in Appendix B and Figure 2:

• Tension cracking was first reported on 8 February 2014 at "Allenmore".

• An inspection of the site was carried out on 10 February 2014. The first tension cracks were observed to extend between "Woodlands" and "Allenmore" in the road surface (shown in red) and had in three days extended both east and west.

• The tension cracks initially appeared as either re-opening of existing features or as hairline cracks.

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• The westward extension of the tension cracks were aligned below and around "Allenmore". The tension crack in "Allenmore" driveway initially dropped approximately 100 mm in two days and external and internal damage was evident. Displacement then increased to 400 mm, and has since increased further. The north western corner to the foundations had moved along the dpc layer (Photo A1).

• New hairline tension cracks had developed along the Undercliff Drive to the western end of "Allenmore" (13 February 2014). These features continued to open up and displacement gradually developed from hairline to 200 mm wide on 17 February 2014.

• The tension crack opposite "Woodlands" and 30 metres east of "Woodlands" opened by 50 mm to 100 mm between 13 February and 17 February 2014 and began to show signs of downslope displacement.

• Inspection of the ground seaward of the site was difficult, hazardous and limited due to the extensive ivy coverage that masks underlying tension cracks. The following observations have been made:

o Tension cracks 2 metres wide and 1.5 metres deep found downslope between "Allenmore" and the western half of the ground anchor beam (approximately downslope of where tension cracking was found in Undercliff Drive) on 10 February 2014 (estimated to be 50 metres to 75 metres forward of the site). During the second visit these features were not evident; this may have been due to the vegetation cover or possibly that further ground movement has closed them up.

o Shallow ground movement downslope of the site within the Gault Clay (mudslide) debris is evident as shown in Photo A2, where the upper 3 metres of soil had moved several metres laterally.

o There are zones where trees are tilted but it is not possible to assess if these are new or old features; they do coincide with the area where more recent features are evident.

o A series of rotational blocks seaward of "Allenmore" and "Woodlands" show that the ground seaward of the exposed rotational blocks have moved relative to the blocks. These features have opened up to 300 mm to 400 mm wide tension features that were several metres deep (Photo A3) on the down slope side.

o The lateral boundary of the shallow slide was seen during the site visit on 13 February 2014 and was approximately in line with the middle eastern quarter of the ground anchor beam.

o Surface water features were encountered approximately 75 metres to 100 metres downslope of the site. It was not clear if these were spring feed and/or if the existing drainage system had become disrupted.

o There is recent shallow movement in the Gault Clay scarp slope over a 40 metre width approximately 200 metres downslope of the site along with a series of trees that have been pushed over.

• The ground anchor beam had multiple hairline cracks at its mid-point (13 February 2014). The beam was subsequently mechanically cut before the larger scale movement began, to save as much of the beam as possible.

• The existing pumped drainage system that pumped water from the landward side of the road into an existing drainage system was disconnected and a temporary surface discharge pipe allowed water to flow over the beam downslope and back into the original discharge system, outfalling to the pond at the bottom of the slope.

Site 9 Woodlands and Site 10 Caravan Park, whilst situated immediately adjacent to each other and within the landslide complex, are subject to two different landslide mechanisms. An extract of the published Geomorphology Map (Sheet 5) is reproduced in Figure 3. This shows Site 9 to

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be located in the head scarp position of an area of multiple rotational block failures that lies immediately above a retrogressing mudslide complex. The retrogressing slide complex extends approximately 160 metres downslopes of Site 9. This is in contrast to Site 10 where the mudslide complex extends to the shoreline. A zone of rotational blocks forms a feature separating the landslide complexes downslope of each site.

Figure 2 Summary of tension cracking observed on 10 and 13 February 2014

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Figure 3 Extract of Geomorphology Map Site 9 and Site 10

The site observations suggest that shallow movement within the retrogressing mudslide complex has occurred, and this is likely to have removed support to the landward rotational blocks. A rotational block appears to have reactivated in the zone separating Site 9 and Site 10, and a new feature (or old dormant feature) developed 150 metres westwards, south of the red sites, to and beneath the Caravan Park.

2.2 Historical Landslide Behaviour

In 2001 a period of heavy rainfall resulted in major sliding at various locations along the Undercliff including Site 9. Further movement and cracking has occurred, with the most recent being in the winter of 2012/2013.

Subsequent to previous large scale ground movements along the Undercliff, a landslide forecast model was developed for the Undercliff by High-Point Rendel in 1996 based on the work by Lee et al (1991). In order to try and predict the likelihood of future movements along the Undercliff, data was collected concerning the occurrence and location of previous landslides and the volume of rainfall preceding them. The model gave a threshold value of effective rainfall (the percentage of total rainfall that enters the ground) over a preceding 4 month period which would be likely to cause instability or increased ground movement rates within the Undercliff landslide complex. When comparing the occurrence of previous landslide events with the corresponding 4 month antecedent effective rainfall (4AER) value it appears to correlate with ground movement events with a good degree of accuracy (Figure 4). Once the 4AER value drops back to below the threshold value the likelihood of further movements at that point in time is reduced. The Isle of Wight Council has employed this model in order to aid assessment of the likelihood of ground movements in areas throughout the Undercliff. Table 2 summarises the trigger threshold values. This placed the rainfall during February and March 2014 as Class 3, and at risk of major instability.

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Landslide Forecast Class

Class Location

Trigger Value Major Minor (4AER mm)

Class 1 <410 Blackgang The landslip, Luccombe, Mirables

Class 2 410 - 540 The landslip, Luccombe, Woodlands Mirables, Blackgang

Class 3 540 - 640 ALL Bonchurch, Ventnor, St Lawrence

Class 4 >640 ALL ALL

Table 2 Summary of Landslide Forecast trigger values based on rainfall

Minor events at Woodlands typically occur in Class 2 events when the 4 month AER value is between 410 mm and 540 mm.

Figure 4 Four Month Moving Average Rainfall and Landslide Events

An image of the site taken on 12 March 2013 is shown in Figure 5. Localised resurfacing was carried out prior to Contract award. A site inspection was carried out on 24 July 2013 during the detailed design phase. An image taken of the site at that time is shown in Figure 6.

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Figure 5 View of Site 9 taken on 12 March 2013

Figure 6 View of Site 9 taken on 24 July 2013 showing resurfacing carried out prior to contract award

2.2.1 Ground instrumentation

A location of the available monitoring points is shown in Figure 7, which comprise piezometers installed at a range of depths to monitor groundwater, and inclinometers to 50 metres depth to measure ground movement.

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Figure 7 Monitoring locations, Undercliff Drive Site 9 - Woodlands

Figure 8 Ground anchor beam monitoring points Data from ground instrumentation are presented in Appendix C.

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During the 2012/13 landslide event surface ground markers were installed in Undercliff Site 9 and the adjacent Site 10 Woodlands. A summary of the records from this is presented in Appendix C. Surface movement of the road continued up to the last available record that was taken in 14 March 2013. The position of the ground anchor beam was re-surveyed on 11 February to compare it against the as-built location. The results are presented in Appendix C.

2.3 Observations from Monitoring Data

The following observations are made:

• Piezometers immediately landward of the site began to show increases in groundwater levels in the first two weeks in December 2013

• Groundwater levels in piezometer 2063 remained above trigger levels following the 2012/13 event until 24 September 2013. There was some evidence of ground movement affecting the road when the site was inspected during the detailed design.

• A rapid rise in levels began on 12 December 2013, and these increased significantly above trigger levels and above those recorded in the 2012/13 ground movement event. Levels here remain above landslide trigger levels.

• In contrast vibrating wire piezometers installed through the highway deeper into the landslide material do not show evidence of groundwater pressure increases.

• Groundwater levels in piezometers downslope of the site are 1 metre to 2 metres higher than previously recorded levels.

• Inclinometer 4304 located in the Undercliff Drive opposite Mount Lavinia shows start of ground movement at approximately 14 metres to 15 metres depth in the period January 2014 to date. There is approximately 10 mm incremental movement per week at this depth. Prior readings suggest negligible displacement at this level. Movement has begun to tail off at this location.

• Inclinometer I4 does not show any appreciable movement; this is located landward of Undercliff Drive, adjacent to "Woodlands".

• Inclinometer 2404 recorded 80 mm movement at approximately 9 metres depth during the 2012/2013 winter ground movement episode before becoming severed.

• In the 2012/13 event surface movement on the carriageway continued to at least the middle of March 2013, some three and a half months after its initiation.

• The change in survey position of the ground anchor beam shows a south-south easterly trend. The western half shows a drop in level of 100 mm, and a south-south east lateral movement of 100 mm to 150 mm on 13 February 2014. Movement at this location is continuing.

• Ground movement from the monitoring information ties in with surface observations. The highest movement is on the western half of the ground anchor beam, and is extending both east and west.

• Subsurface movement has also extended to the inclinometer opposite Mount Lavinia suggesting more extensive ground movement at depth in the top of the underlying Gault landslide debris.

2.4 Preliminary Stability Review

Construction at Site 9 commenced on 14 November 2013 and at the time of the geological failure excavation of the existing ground had been carried out to accommodate the ground anchor beam and select granular fill earthworks. The reinforced concrete ground anchor beam had been constructed, and eight ground anchors drilled but not connected to the beam or stressed.

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A preliminary review of stability analysis has been carried out to assess if the works were detrimental to stability of the slope. This shows that the construction works have a slight improvement on overall stability, and therefore not a component driving failure.

The landslide system downslope of the site comprises a retrogressing mudslide within landslide debris, largely comprised of disturbed Gault Clay. Typically shallow near surface instabilities are reported to occur i.e. within the upper 3 metres to 4 metres of surface levels. Groundwater levels in this zone have risen by 1 metre to 2 metres above last year’s levels, and currently approximately 3 metres below ground level (mbgl) 40 metres downslope of the site reducing to ground level approximately 120 metres downslope of the site. This is consistent with site observations of seepages/springs downslope of the site. The much higher groundwater in the shallow slide complex significantly increases the risk of the instigation of shallow slip surfaces. The increase in groundwater has been included in the stability model to assess the risk of shallow ground movement. It is found that shallow slips in the mudslide downslope of the site have factors of safety below unity and are more likely to fail than the larger slip mechanisms affecting the road directly.

It was recognised during the tender and detailed design that the stability of Undercliff Drive was sensitive to shallow landslides in the ground downslope of the site; this area lies several hundred metres outside of the designated red site and hence stabilisation of this element of the landslide is out of the scope of the current contract i.e. shallow ground movement downslope of the site was considered as a "geological failure mechanism".

The site observations and the stability model indicate that shallow slides downslope of the site had developed, with the formation of much wider tension cracks in the ground downslope of the site; at the same time hairline features and slight reopening of existing defects were apparent in Undercliff Drive. This type of movement would have led to rapid loss of support to the rotational blocks and may explain why the tension cracking and landslip features in Undercliff Drive developed in a relatively short timeframe.

It is noted that the existing drainage discharge pipe was observed to be intermittently exposed and likely to be leaking; surface water features were evident in the proximity of the discharge pipe; it is not clear if they represent one of the same feature. The current discharge system has been repaired and reconnected to the existing drainage pipe that outfalls to the pond at the bottom of the slope.

3. IMPLICATIONS OF FAILURE

• A significant Geological failure occurred prior to the installation of the proposed stabilisation solution for site 9. The failure has extended approximately 150 metres west from the previous defect and extends beyond the zone of support that would have been provided by current ground anchor strengthening solution.

• The geological failure has expressed itself in a relatively short time frame.

• The failure has occurred partly along the previous geological features, but during this event it has extended a significant distance west (by approximately 150 metres) and downslope of the red risk site boundaries, into private land. It is possible that these are new geological features or that the failure has resulted in reactivation of old dormant features.

• Groundwater levels in piezometer 2062 remained above trigger levels after the 2012/13 event. Site inspections carried out during the detailed design showed some evidence that the highway had suffered tension cracking/ settlement.

• From 12 December 2013 groundwater levels rose rapidly and continued to rise significantly higher (approximately 0.88 metres) than those recorded at the time of the 2012/13 failure.

• Site observations indicated that shallow ground movement downslope of the site was occurring in the early stages of landslide development, with tension cracks some two

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metres wide seen immediately downslope of the site. Shallow ground movement will have led to loss of support (tension cracks seaward of the exposed rotational blocks) and most likely led to the subsequent reactivation of the smaller rotational blocks and rotational blocks adjacent to the Undercliff. This loss of support may explain why movement occurred relatively quickly in the Undercliff Drive.

• Groundwater levels at the site remain high and there remains a very high risk that movement will continue.

4. INTERIM MEASURES

A large scale geological failure has been initiated and developed in a relatively short time frame. The following measures have been carried out:

• Ground anchor beam was cut to avoid total loss

• Vehicular access is no longer possible due to the landward extent of the failure

• The existing pumped drainage system was diverted over ground to avoid subsurface leakage.

• Monitoring has been established and is continuing.

5. INFORMATION TO ASSESS EXTENT OF GEOLOGICAL FAILURE

The following information and actions have been implemented to assess the extent of the geological failure.

• Review remediation proposals given the revised site conditions

• Continue to collect all monitoring data available to date and rainfall data

• Increase frequency of inclinometer readings to fortnightly

• Monitor surface points in road surface at weekly intervals

• Monitor width of cracks in road surface at weekly intervals

• Carry out regular reviews of monitoring data with Island Roads to assess continuation of movement Resurvey the ground surface seaward of the site along the same cross section as that carried out during the design to establish the change in ground profile once the landslide event is complete

• Once the current landslide event is complete the ground surface seaward of the site should be resurveyed along the same cross-section as that carried out during the design to establish the change in ground profile

6. ESTIMATE FOR TIME FRAME FOR GEOLOGICAL FAILURE RECTIFICATION

At the time of preparing this report the full extent of landslide and its effect on Undercliff Drive Site 9 is unlikely to have been fully realised. Since the first issue of this report ground movement has continued. As a result a full programme for rectification of the red site has not been developed at this stage; this is dependent on the length of time ground movement continues. Ground movement continued for a period of 3 months to 4 months during the 2012/13 landslide

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event. A timeframe for rectification will be developed subsequent to this failure report (or as to be agreed with the Isle of Wight Council). The initial outline programme of the proposed actions which have now been completed is given in Appendix D.

7. ESTIMATE OF FAILURE COST

An estimate of failure cost has not been established as the geological failure is still continuing. Given the movement that has occurred the current ground anchor solution is no longer suitable. If the road is to remain in its current alignment then significant fill would be required to raise the road back to an acceptable alignment. Remedial measures, if they were deemed possible, are likely to use a combination of techniques, and most likely include as one of the components deep wells to control groundwater levels. Groundwater control was initially proposed by during the tender stage, however subsequently not taken forward due to environmental restrictions associated with the site. A number of potential remediation proposals are presented in Appendix 5 of the Island Roads Report.

Isle of Wight Highways PFI Ramboll Woodlands Site 9 Undercliff Drive Page 12 Report Ref: 61030594-9-R02 Geological Failure Report

8. REFERENCES

Lee E M and Moore R 1991. Coastal Landslip Potential Assessment: Isle of Wight Undercliff, Ventnor. Report to the DoE.

Isle of Wight Highways PFI Ramboll Woodlands Site 9 Undercliff Drive Page 13 Report Ref: 61030594-9-R02 Geological Failure Report

APPENDIX A

PHOTOGRAPHS

Isle of Wight Highways PFI Ramboll Woodlands Site 9 Undercliff Drive Report Ref: 61030594-9-R02 Geological Failure Report

A 1 1 Photo of north west corner of Allenmore showing foundation displacement

A 1 2 Shallow sliding Downslope of the Site

Isle of Wight Highways PFI Ramboll Woodlands Site 9 Undercliff Drive Report Ref: 61030594-9-R02 Geological Failure Report

APPENDIX B

GROUND MONITORING DATA

Isle of Wight Highways PFI Ramboll Woodlands Site 9 Undercliff Drive Report Ref: 61030594-9-R02 Geological Failure Report

Appendix B- 1 Monitoring Locations, Site 9

Appendix B- 2 Groundwater Records Well 2062

Isle of Wight Highways PFI Ramboll Woodlands Site 9 Undercliff Drive Report Ref: 61030594-9-R02 Geological Failure Report

Appendix B- 3 Groundwater Records Well 2063, landward of the Highway

Appendix B- 4 Groundwater Records Vibrating Wire Piezometers 1404 with the Highway

Isle of Wight Highways PFI Ramboll Woodlands Site 9 Undercliff Drive Report Ref: 61030594-9-R02 Geological Failure Report

Appendix B - 5 Groundwater Records – Standpipe Piezometers Downslope of the Highway

Appendix B- 6 Inclinometer I/4 - cumulative deflection plots

Isle of Wight Highways PFI Ramboll Woodlands Site 9 Undercliff Drive Report Ref: 61030594-9-R02 Geological Failure Report

Appendix B- 7 Inclinometer I/4 - rate of displacement plots

Appendix B- 8 Inclinometer 4304 Cumulative Displacement Plot

Isle of Wight Highways PFI Ramboll Woodlands Site 9 Undercliff Drive Report Ref: 61030594-9-R02 Geological Failure Report

Appendix B- 9 Inclinometer 4304 Incremental Plot

Appendix B- 10 Inclinometer 2404 Incremental Plot. This instrument was severed due to ground movement during January/February 2013.

Isle of Wight Highways PFI Ramboll Woodlands Site 9 Undercliff Drive Report Ref: 61030594-9-R02 Geological Failure Report

Appendix B- 11 Surface Monitoring Points Established 2012/13 event

Appendix B- 12 Change in Ground Anchor Beam Level from construction to 14th February 2014 (Movement direction: Diff E: Easting, Diff N: Northing, Diff Z: Level).

Isle of Wight Highways PFI Ramboll Woodlands Site 9 Undercliff Drive Report Ref: 61030594-9-R02 Geological Failure Report

APPENDIX C

OUTLINE PROGRAMME

Isle of Wight Highways PFI Ramboll Woodlands Site 9 Undercliff Drive Report Ref: 61030594-9-R02 Geological Failure Report

ID Task Task Name Duration Start Finish W-2 W-1 W1 W2 W3 W4 W5 W6 W7 W8 W9 W10 W11 W12 Mode M T W T F S S M T W T F S S M T W T F S S M T W T F S S M T W T F S S M T W T F S S M T W T F S S M T W T F S S M T W T F S S M T W T F S S M T W T F S S M T W T F S S M T W T F S S M 1 Undercliff 9- Woodlands 0 days Mon 10/02/14 Mon 10/02/14 10/02 2 Initial Site Review 30.47 days Thu 13/02/14 Tue 25/03/14 3 Site Visit 1 day Thu 13/02/14 Thu 13/02/14 Deng 4 Site Visit 1 day Mon 17/02/14 Mon 17/02/14 Deng 5 Prepare Failure Notice 7 days Mon 24/02/14 Tue 04/03/14 Deng[25%],Dir[50%] 6 Issue Action Plan to IR 0 days Tue 04/03/14 Tue 04/03/14 04/03 7 Meeting IR 0 days Tue 04/03/14 Tue 04/03/14 04/03 8 IR collate monitoring data 4 days Mon 17/02/14 Fri 21/02/14

9 Finalise Action Plan and 0 days Tue 11/03/14 Tue 11/03/14 11/03 issue IR 10 Issue to IOW Council for 1 day Tue 11/03/14 Wed 12/03/14 review 11 Address IOW Comments 0 days Tue 25/03/14 Tue 25/03/14 25/03 12 Monitoring 38.33 days? Wed 12/02/14 Wed 02/04/14 13 Establish surface peg 1 day? Mon 17/02/14 Tue 18/02/14 monitoring in landslide forward of site 14 Establish surface 1 day? Mon 17/02/14 Tue 18/02/14 monitoring in road 15 Monitoring 38.33 days Wed 12/02/14 Wed 02/04/14 16 1 1 day Wed 12/02/14 Wed 12/02/14 17 2 1 day Wed 19/02/14 Wed 19/02/14 18 3 1 day Wed 26/02/14 Wed 26/02/14 19 4 1 day Wed 05/03/14 Wed 05/03/14 20 5 1 day Wed 12/03/14 Wed 12/03/14 21 6 1 day Wed 19/03/14 Wed 19/03/14 22 7 1 day Wed 26/03/14 Wed 26/03/14 23 8 1 day Wed 02/04/14 Wed 02/04/14 24 Failure Report (Cl 12.8) 66.67 days? Wed 29/01/14 Fri 25/04/14 25 Interim Failure Report 52.2 days Wed 29/01/14 Mon 07/04/14 26 Review data up to failure 2 days Tue 25/03/14 Thu 27/03/14 Deng[120%]

27 Interim monitoring 1 day Wed 29/01/14 Wed 29/01/14 Deng[94%],Dir[25%] review 28 Assess 2 days Thu 27/03/14 Mon 31/03/14 sensitivity/adequacy of existing solution 29 Prepare report 2 days Mon 31/03/14 Wed 02/04/14 Deng,Dir[50%] 30 Issue to IR 0 days Wed 02/04/14 Wed 02/04/14 02/04 31 Meeting with IR 0 days Fri 04/04/14 Fri 04/04/14 04/04 32 Address IR comments 1 day Mon 07/04/14 Mon 07/04/14 33 Issue to IOW Council for 0 days Mon 07/04/14 Mon 07/04/14 07/04 review 34 Finalise report 17.67 days? Wed 02/04/14 Fri 25/04/14 35 Review monitoring and 3 days Wed 02/04/14 Mon 07/04/14 Deng[67%] incorporate monitoring review 36 finalise assessment of 3 days Mon 07/04/14 Thu 10/04/14 Deng,Dir[17%] existing 37 Issue Report 0 days Thu 10/04/14 Thu 10/04/14 10/04 38 Meeting with IR 1 day? Thu 24/04/14 Fri 25/04/14 Dir

Task Summary External Milestone Inactive Summary Manual Summary Rollup Finish-only Project: Undercliff 9 Notice programme Split Project Summary Inactive Task Manual Task Manual Summary Deadline Date: Wed 04/06/14 Milestone External Tasks Inactive Milestone Duration-only Start-only Progress

Page 1 GEOLOGICAL FAILURE REPORT: RED ZONE 9 WOODLANDS

APPENDIX 2: Drawing 1 – Undercliff Drive Landslip Diversion

iii

1.22m RH

REW LANE Track Def

Track 210.6m Hobbit House FB Path (um) Sinks ED Bdy Wroxall Down FF The Elms 220.7m Path (um) 193.2m Path (um) FB HIGH STREET

Dismantled Railway 94.8m Sinks Path (um) Pond ED Bdy Chez NousIssues Burstalls 141.3m 1.22m RH West Winds West View Track 62.4m FB The Cottage Bagend Streamside 222.4m Underhill Forge Cottage Corner Cottage Path (um) Meadowside Cambray Little Acres Fair View 151.0m Lane End 114.2m Glenmay FB Pelham Cottage Whits-end 98.1m Pit Stockbridge Manor Farm Stockbridge Cottage Barn End 103.0m The Cottage Golf Course (disused) 101.4m Scorpies Ivy Cottage Jolliffe's Farm 127.7m Mulberry The Barn House Issues Stockbridge Manor Haywards Whitwell Station El Def Mayhill Hillside Cottages 81.5m Sub Sta 121.7m 209.0m Greenhills 4 Stone Cottage 63.6m Wren Rew Farm Waterfall Issues Fernbank Swallow Track NETTLECOMBE LANE Depot Heronfield Nettlecombe Little Thatches Cottages Wheat WILLOW CLOSE Alban Cottage Nettlecombe Robin Oars Issues Loose Barley FF Greenleas Path (um) Brookside Cottages 120.6m CLOSE Ends Issues 113.1m Pitville Bungalow CHESTNUT FB Track Track Sandstones ALBAN WAY 173.4m HAZEL CLOSE El Sub Sta 98.8m Track WHINSCOT CLOSE Sunrise Corner Nettlecombe Farm Butt Lea Cavallet Heron CF SLAY El Sub Sta 84.0m 113.9m Pond The Orchard 142.8m LANE FB Grasmere Yarborough ST MARGARETS GLADE El Sub Sta BLANK OUT 100.2m FB Slay Rise The Barn 110.5m REW LANE Und Track Rew Farm Rew Farm St Martins Lodge The Mead Rew Down House Cottages Track Bradings 117.8m Garden Issues Cottages 65.4m Glengariff 1.22m RH Estate Badgers Bierley HIGH STREET Gas Gov Playground Haven Saya Rumah 205.8m 109.4m Week Down L Twrs The Kilnside Cottage Byfield Ponds Prickles MEADOW CLOSE Ash Court 71.5m 121.1m EXISTING SIGN Track Track Chestnuts Glenfield Pit Farm Path (um) Strathwell Ferndale ROAD Cottage Ventnor Community Bexhill Cottage Strathwell El FB Dale LB L Twrs Sub Sta Early Years Old Chapel House Depot Brading Path (um) LOWTHERVILLE Beerlays BANNOCK Cottage War Meml LUDBROOK WAY Dismantled Railway NEWPORT ROAD Brooklands CF Hazel Bed BANNOCK ROAD Bay Leaf LOWTHERVILLE Path (um) Cottage TCB Track RAYNERSLOWTHERVILLE ROAD Apple Tree Wr T Blackgang Cottage 67.3m Vine Strathwell Firs Hollyberries El Sub Sta 123.7m St Margarets Path (um) Cottage ROAD Chilling Wood 102.1m Rose 125.7m 6'6" CR183.3m Cottage Springfield ED Bdy Niton Downsview 133.4m BANNOCK ROAD Path (um) Horseshoe Cottage Garage Ventnor Industrial Estate Rosewood Old School B 3327 A3055 Issues House Old FB 148.9m 1 ChurchCottages House 209.2m 2 2 miles Highclere Hillside Tumulus Eastdene FB The Old Coach House PH (site of) Reservoir (covered tank) Beech Copse Strathwell Park North House The White Clovelly Strathwell Horse Inn Wroxall Down Path (um) Copse FB Issues 109.2m South House Brookfield Whitwell DOWNLANDS 164.8m ED Bdy FB Shelter St Michaels 129.5m CP Path (um) Track LB Reservoir Shute Cottage CRES TCB Newport(covered) (A3020) LITTLETON Path (um) Hillcroft El Sub Sta Path (um) Rew Copse El Sub Sta Downside Ingadene REW CLOSE Union Cottage Rew Copse Green El Sub Sta Trenale Shelter Dolphin Highlands Andrews CLOSE Garage Track 205.5m St Godshill Pond Ventnor Farm Alma 73.3m Halcyon BANNOCK ROAD Track Cattle Grid Path (um) Cottage Greenfields Ventnor York Villas 131.9m Monks Yelding EllersieHouse Tumuli NEWPORT ROAD Alpine Industrial Whitwell Week Farm Tumulus 144.7m Lowtherville Path (um) GLOUCESTER ROAD Estate Farm (site of) Und Applegate Bay Tree Cottage Greystone Maisonettes El Sub Sta Drain 1.22m RH Pyrmont Cottage Cottage 128.4m FB Down Lane Wren Cottage YORK ROAD El STRATHWELL CRESCENT Cottages Blackgang Davmar DOWN LANE Sub Sta El Sub Stas Highcliff St Marys

Netherfield Tor Bank Pond Cottages Leswood Kingates Barn Path (um) Court Club OLD STATION ROAD Drain ED Bdy The Croft Kingates Copse El Sub Sta Wesley The Cottage PO Ppg Sta The Wighthaven Hill Court Niton FF Tavern Cottages Anchorage Cross Berryl 125.5m The Farm House FBs El Sub Sta Ravens 87.6m Windy Ridge Gas Gov 76.6m 80.9m Tumulus KEMMING Myrtle Whitwell Farm Berryl Shelter St Angelo GP 81.3m Springwood Cottage Cottages ROAD Little Orchard 82.8m St Mary and 87.6m Sottosopra North Kingates Mountside Saxons Kemming LB Green CORNWALL ROAD GP 134.9m DOWNSIDE TCB End Farm El Sub Sta Kingsmede Cottage 82.5m St Rhadegund's Gables Path (um) Church Path (um) Southend Lowfield Pennyfeathers FB Path (um) Ravenscourt Little Lodge 83.2m Week Down 197.4m Prospect Fairlight Fossip FB Cottage Berryl The Orchard CR GP 106.9m Little Garth Mount Surgery South The Cottage 80.2m The house of Farm View Grove Copperfields Adela Montrose Place Orchardleigh 95.6m St Francis 81.3m 80.6m Ash Golf Course 88.1m Melville Cottages The Dene Tumuli Kaysgarth LB KINGATES LANE Lodge The Haven Ash Glen Fairways (sites of) The Kingates Brembae Ash Dale Chantry Way Bungalow Brook Lodge Primrose Cottage Path (um) PC Cottages Kingfishers Primrose Track Villas Sunglaze OLD SHUTE Clarendon Downlands 78.2m 190.2m 131.1m Council Yard Villa CottageRose Track Jasmine Cottage Park Cottage CottageKilda Path (um) Brookside Garden Cottage Bywell 73.8m Bridleway El Sub Sta YarboroughVilla GP 71.2m Havensbush B 3327 House Path (um) 65.6m

Head Down Sunnydale The Moorings Waterdine Rew Down (playground) CW Path (um) The Old Rectory 87.7m Club House Brick Well Path (um) Wayside House Popes Orchard Roseberry Chapel GROVE ROAD 102.6m LB CW LB Ashford 1.22m RH Ppg Sta El Sub Sta Glenfield 89.4m OCEAN VIEW ROAD Pond Pond 114.0m 109.3m 95.5m Highfield Farm Cottages Vergemount 123.3m Delaner TCB Seagulls El Sub Sta Glendower STEEPHILL DOWN ROAD 78.9m BELLEVUE Pilgrims Old School House Casa Copland 69.5m Way 130.5m St Alban's Steps Nostra House Highlands UPPER ASH DRIVE Drain 95.0m Drain ASHKNOWLE LANE The CROCKER LANE Gable Ashknowle House Hall 100.0m RD Brent Hill Track St Vincent Ferrer

Church Burlington The Lodge Ponds GP 117.5m Orchard Mostyn Hotel Catherines ZIG ZAG ROAD 62.0m Cottage Waters Way House

FW St Path (um) 143.5m ST ALBAN'S ROAD Priory Lodge 72.0m Touchdown Montana Path (um) CastleBellvue The Ridge Car Park Hillside Cinxia Cottage 105.0m Upper Ash Little View House THEGROVE Cottage Beacons Chapel House MARLBOROUGH ROAD Track North View Farm Ventnor Belgrave View Garage View LB Briars St Alban's Steps Castle CR Cliff Drain 58.2m Salduns ROAD Path (um) Cliff Barian ALPINE ROAD ST ALBAN'S GDNS Hillside Farm WEEK LANE Priory Court A 3055 47.9m Elsinore Head 108.1m Down Ashwood Silos Heathcliffe ROAD Cottage 110.7m Barn Ponds Stone Path (um) GILL'S CLIFF Woodlands 53.6m ZIG ZAG El Sub Sta 113.2m Drain Fusina Grove House Dawn's The Limit View 70.2m (Surgery) Linden Lea ED Bdy 73.8m Grove Keep Cottages Crab Cottage Cove Tank Belgrave Cottage Court 35.8m Cemetery Pine Point Enmore House El Southcliff Yarborough Ct Chy-War-Dinas BELGRAVE ROAD Week Cottages Path (um) Sea Grove Pegasus Club Dismantled Railway 71.9m Sub Pond Rhosgobel Staplehay Royal Sta De 36.4m Quiet Hills LyncombeThe Montfort Pavilion Wansfell 47.7m Wind Turbine Fair Winds 106.6m Hotel ESPLANADE Elland Little VENTNOR ROAD Fairhaven LB Winyards Cottages Avalon Haven Windrush Belmont ROAD St Andrews Swiss Hilbank 41.4m Cott Skerryvore Paget House Wellington Wyngreen Claremount Hotel LB Walton Marula El Sub Sta Lindum House GILL'S GP (Hotel) CLIFF ROAD Southlands Stella Maris Cottage Medina 77.9m House Down 46.7m Path (um) 90.6m Jobsons Farm 102.9m Byrnhill Grove Trewartha FS MARINE PARADEHillbrow GP

ALMA RD Merindol Silvermere River Yar Path (um) Boathouse CandlelightLimpets Cottage 109.9m 87.0m Amusement Greenbanks Chalk Park GP Hadley Pond Path (um) Hills WHITWELL ROAD Belhaven House 34.5m ROAD Arcade St Catherines Cottage Whitewebbs Pelham Paradise Walk CASTLE ROAD Glenlyn Eversley FS BATH Cyprus Swimming PoolHotel Cleeve 6.2m Posts 5.7m Posts Cottage Path (um) Melville Hyrst Sydney ESPLANADE Lodge Lodge Sand Issues CHATFEILD ROAD Malham Heatherstone BLANK OUT EXISTING White Garth South 41.1m Anglesey 100.9m Bank Lindula Path (um) Brook House 23.0m St Lawrence ASHKNOWLE LANE GP Merrie LB St Maur The LilliesHills End Meade Cottage Mean High Water Pond Dormy The Valley Cleeve PC Drain Watcombe Bottom Thalassa Puckaster Arno Hillslea Court Groyne Collects Sports Ground House Sand Hanaper (um) Allandale House 11.9m PH Ventnor (A3055) House Reservoir Path Putting Green 105.4m The TorsSteeple High Clarance PARK AVENUE Folly Shelter Springs Bank Castle Way Claydon Path (um) House Park Cottage SIGN Fernleigh Lodge Shelter Meadow View Caravan Site Gas Gov FOXHILLS Park Aviary alternative route for large vehicles CR Pavilion Collects View Sand Path (um) War Memorial Car Park FB Track Guide 36.3m PC Ventnor Bay Drain Paradise Walk Post El Sub Sta Bandstand Pavilion Pond LB Path (um) SD Osiers 108.7m Path (um) Collects The Undercliff Track Track 37.1m FB CASTLE CLOSE Works Groyne Track 107.6m 103.2m WHITWELL ROAD Path (um) FB Ventnor Park Hoye's Farm Osiers CASTLE COURT Park 161.1m Newport (A3020) Mead Path (um) Shelter WHITWELL ROAD Clock GP GP El Sub Sta UpperHouse C Tank 89.9m GARDENS Garden Path (um) 111.5m Drain 105.6m Path (um) UNDERCLIFF Lodge Post Putting Green Quarry 32.5m Shelter Path (um) 110.7m Drain (disused) Shelter Steephill House Western Cliffs Track Drain 111.6m LB Track Blackgang Tall Boulders Rock WoodlandTimbers Pond Ramparts Issues Dean Farm 97.9m Court Glencliff 90.7m Seacroft North Butts WHITWELL ROAD 112.0m Mean High Water Burwynns Flowers Brook 6'6" 92.0m Sheldonia Highbanks Lodge Ppg Sta Boulders

Boomerang Niton St Lawrence 6'6" Dwarf 112.0m RadstoneCroft Lyndhurst Crossing Cottage Path (um) Rocky STEEPHILL ROAD The Old Bakehouse 100.6m GP 101.8m Engadine Tor

El Sub Sta Steepleton NEWPORT Tanglewood Dunnock Shipton Villas Petit Little Bevois Butt Tor El Sub Sta 21.5m Wyncroft Barleycorns Ventnor PELHAMROAD STEEPHILL COURT ROAD Holmwood Flowersbrook Steephill Water A3055 Green Flowers Brook MeanLow 1 Well Rosebank Lea Well Railway Broadview Cascade 2 2 May Flower Warbens STEEPHILL 2 miles St Rhadegund's Path Dismantled Halcyon 3 miles ROAD A3055 Glen Avon House Path (um) 24.7m Rydal Caravan Park Recreation Ground Pond

107.8m High MLW 113.7m The Haven Barn 140.4m Downs View A 3055 Bevois Path (um) 112.8m Castle Woodhaven Pipe Line South Court Sand End Manser Stones Stonehaven Letter Box Drain GDNS STEEPHILL The Inch 24.6m Stone Pinjarra 92.6m 104.7m Cricketers Rest (PH) Place Steephill Track Drifters El Sub Sta Track Roseglen Stone Place Newport (A3020) Cottage The White Boulders A 3055 House Stone CottageThe Mount Helvellyn Western The Elms Path Primrose Cott Pavilion Lines Arno Villas Sunnylea Majanders GP Steephill The Coastal Slope Heather Roost Steephill Hope Cottage House Redgun Cottage Car Park Beacon Brambles Track Godshill Bramble Path (um) Tamarisk Cottage Sea Alma Cottage CR PARK LOVE LANE Winds Scallop Shell Cottage Buffers CottageJoy 85.1m Pollard Willow Ladyacre Farm Path (um) Slipway 106.8m Buddleia Cherry Tree Cottage INGLEWOOD Blyth Cott DOWNSIDE AVENUE Bramden El Sub Sta Boulders Pan Cottage Cottage Meil'e Reservoir 31.9m PCs Cricket Dismantled Railway (covered) Western Cliffs Riguewihr Signal Point FS Ground Boulders Ivy Russett Sand Cott Cottage Path River Yar Blackgang IVY CLOSE Talsa Path El Sub Sta GP THE GREENWAY The Glenn 119.2m 119.7m Issues ST LAWRENCE SHUTE The Boathouse Track GP Cliff Dene Caynes Court West Kaster CP GP Bank End Mean High WaterCastle Cove View Farm House Thatched PRIORY Issues Cottage Niton Tudor Orchard WALK The Cabin NITON Meade PARK View T Slope Boulders Boulders Und UNDERCLIFF DRIVE West Blackgang Rosebery 85.8m Colindale GP View ROAD Melmont Downside Blenheim INGLEWOOD Genevra SHUTE HomesteadThe Methodist Cottage Track Path (um) Pond CottageApril Niton L'ancresse Kimberley 37.5m PC 6'6" Green Pastures Church Beulah Bank End Farm Ventnor Botanic Garden Path LACEY'S LANE 87.5m Path (um) DW Niton Highbank Coastal Slope The Lighthouse Cottages Pond PAN LANE NEWPORT Sunnybank Meadow Side South LOWER FIELDS GP Combe Lodge Place Path (um) Mitzvah House CHATFIELD ROAD 111.6m Slipway Slipway Daisys Cottage St Rhadegund's Path Millsea Highfield Groyne A3055 Boulders Spring Palmers Forge Tel Ex Path (um) Sand Mean Low Water Cottage Ashleigh Cottages Pelham Wood 1 Brandon Cottage Stable Golden 100.9m Lands Little Rosia Cottage Steephill Cove Rock 2 Whereaway 2 miles Elmleigh HOWARD CLOSE Villa 106.5m HawksworthTillington Verbena Springbank Bartons CottageRose Amelia MLW Spring Cottage The Undercliff Niton Manor Cottage OrchardFairways Cottage South View Boulders and Shingle Church View Cottage The New Melbury Cottage Langley Track Rectory 103.7m Nutkins Lisle Combe Cottage Mean Low Water Yar Rookley 90.6m Niton Manor Farm Pictou Cottage Cottage Seven Sisters GP Herveys Sinks GP The Doctor Henry Behrend Walk PaxIssues 93.7m Puckwell Cottages LB ALLOTMENT ROAD Walk Rock Tunnel Niton Manor RECTORY ROAD El Sub Sta Sinks Pelham House Brooklyn97.1m Lisle Combe Richmond MLW Church Cottage Random Sheep Wash 100.9m St Joseph's Stones 89.5m (disused) 29.6m Pond Lych Gate TCB TOWN END Woodpeckers Rock MLW Springs Playground George STREET R C Church The Newport (A3020) Broadacres FS CHURCH Stonebowe FISHERS Dormy House A 3055 St Lawrence Blossom Gate CP Wood Side BLANK OUT Beverley School Kingscote 89.4m Pond Well Ye Olde Niton Barns Cross Cottage House 55.6m Rocks (restored) Niton Glebe Car A 3055GP Reservoir Youth House LANE Park Breakers Sound MLW (covered) Ppg Sta Club The Stonebowe Larkrise Aprils Issues Pump Path (um) Hall Cottage The Old Cottage Boulders Godshill White Little Gardens Hall Spring

Tamarisk Cott PC Lion Stonebowe Westgate Cottage Pond Ponds Path (um) GP Sabon Gari (PH) RECTORY 60.0m Selwyns A 3055 Brook TWINING ROAD A 3055 Lodge Greenacres Rectory 90.2m ED Bdy CLOSE Home Farm Spring Rydal Cottage 81.5m Honeysuckle Cottage LB Mount Track 41.0m EXISTING SIGNS Shelter Iris Cottage 98.6m CottageSundial (Source of Collects GP St Annes GP LANE Cottage 35.0m Marine Villa PUCKWELL Station House BARN Pond River Yar) Surgery Tigenare 77.1m El Sub Sta Orchard Blackgang Spreads Shelter Pond Kings Manor Farm Frognal SISTERS Home Farm Bay Outfall River Yar Woodcliffe Liby GP ROAD 66.0m TCB El Sub Sta House 106.8m Fuchsia 71.9m Cottage Trebener Cottage SEVEN Issues Path (um) East Shute Cottage Boulders Football Ground Springhead Merryweather PO Shute Cottage The Old Rectory Winfrith HIGH STREET FB Reservoir FB Pond Badger Cottage Rose St Lawrence Niton (covered) Rest Harrow House The Forge Fairwinds Boulders 111.4m Mercia Cott Bank The Old Church FB Manor Cottage Mean High Water Manor View The Shute Blackgang Cottages Pond Douglas End Fields Woodcliffe FB Slipway Summertime Lodge Hotel Shingle Oatmeal Crag Track Eades PUCKWELL FARM 6'6" 103.6m A Mean Low Water Path (um) Niton Und Cliff Cottage La Mer Rocklands Cherry Track Spring St Rhadegund's Path (um) Bank Manor Rare Breeds and Trees Chestnut Cottage Uphill White Pines Springhead SCHOOL The Fields Nursery Waterflow Park Path (um) LANE The Haven Track Tolverne Rickess Post Office Shekinah FB Orchard Bay Lodge El Sub Sta Transmitting Station Rockmount 40.5m New Bank End A3055 Cottages Farm Spreads 1 BLACKGANG ROAD Sherwood Rill El Sub Sta St Rhadagunds 2 2 miles Track El Sub Sta Cottages April St Lawrence Farm War Meml Rocklands Cottage Track Mast Church Shingle Boulders High Hat Niton Primary School Mast Maranatha Yelf's Sunnycroft Lynwood Ballya CliftonVilla Playing Field Cottages Rockmount Pond Track Melrose Post El Sub Sta Mount Bay Clifton UndercliffMoorings St Lawrence Whyteleafe Path (um) Cottage Little Field Dene FF St Francis RH CP Woolverton BLANK OUT EXISTING Ashdown St Rhadagunds Lodge Salem Track Newport (A3020) Koinonia B UNDERCLIFF DRIVE ED Bdy Briar The Cliff Salem INSTITUTE HILL El Sub Sta St Marys Lodge Cott Rock The Haven Crag Miramar LB High St Lawrence LB Underwath MLW Track 68.7m Cottage Dene Cottage Vectis The Garth Ridge Godshill SPINDLERS ROAD PO SISTERS CLOSE 53.6m Toll Gate Gadshill Cottage SEVEN Wingcliff Freshwater A 3055 Cottage Rocklands Drain GLEN APPROACH Glenroy El Sub Sta St Catherines Silver Woolverton Cottages Boulders SIGN Def Mist House Villas Path (um) Pitcairn Farthings Bethshan 62.6m Nursery Poynings St Anns Rocks Blackgang Southward Church Locks Farm Larkrise Blackgang Niton Pumping Craigie MLW Barrington Brewers Lodge The Firs Lodge A3055 Lodge Station La Pankina Ponda Rosa Falaise Cottage Craigie El Sub Sta CLOSE La St Lawrence Heath Woody Fairways El Sub Sta Niton Bank El Hill Sunnymead Carfax Inn House Sub Sta Satis Rock Newport 114.7m St Catherines Belvedere Summerhill Hall LB Path (um) Celadon House Cottage Dilkusha GREENLYDD 68.2m Dovecote MLW Cottage 70.8m Pond THE GLEN West Wind Owl Priory Bonniface Wellworthy OLD PARK ROAD Twinkles Issues (A3022) Stones Sabah Hillside Rock Laconia Swallows Netherdene Edge Pond Sinks Rest Hunters Pond The Dale Way Fair Lee Sylvan Seas Wild Cliff Nutcombe Cottage The Old Manse Monte Bre Keewadin WOOLVERTON ROAD Wightbullys at Seacrets Woolverton Glenmoray High Madeira Maycroft South Manor Issues Bank Idle Ambion Deep The Glade CLOSE Rocks El Belvedere House Craigie Lodge Ocean Breeze Woolverton Salopia Sub Sta Thimble House Pine Tops Gardens Cottage The Bungalow Track Ventnor Wendover Path (um) Elm Cottage Pipers Beech Cott Barn Trumarton Conamara Def Woodlands HUNTS ROAD VERLANDS The Spinney Way Sonsbeek Cottage House Cheviot Fleet House High Def Cottage The Trees Windwood Sandrock Cottage Spring Vale Ambledene The Stables A3055 Thatches Retreat Marlbrook Penbryn Rondebosch Gazebo Hejira Issues ED Bdy Tidewater The Dell Sir Richard's Newtons Northern 65.2m El Sub Sta Peppercorns Morningside The Cottage Cove Path (um) Star Crathorne 1.22m RH UNDERCLIFF DRIVE Arabian Haze Knights Drakefell Highfield Caravan Site Ash Timber Little Coombe Foxes Gable Track Boniega Glenholme SHUTE End Havens LB Half Moon Cottage End Pine Path (um) Gap Boulders Track Charleswood House High The Undercliff Whyte Path (um) 67.7m Little Grange BARRACK Rock Firs Spring Green Bank Und Woodington Old Park LANE Cottages BOXER'S Allenmore 68.0m Path (um) Path (um) Dolphins House Mount Sewage Works St Lawrence Lavinia Undercliff Gardens Track Charles Wood Track Woody Bay Cottages (Nursery) Willow Wood Track MS Spring 83.5m 64.1m Ridge House FW Old Park Mean High Water The Old A 3055 Lodge Issues OLD PARK ROAD Little Orchard UNDERCLIFF DRIVE Coach House LB BPs 64.4m The Undercliff Glen Path (um) Path (um) Low Water Orchard End 59.4m Caravan Park Track Issues Mean Stone Haddon Lake House Westcliff 98.1m 71.8m Springs Chimney Woody Point A Path (um) Shingle Fountain Westcliff Lodge The Orchid House Tunnel Path South Bank Orchard FB Lake Grove (um) Corner Sinks Path (um) Path (um) Ways Longstock Track FB El Sub Sta Undercliff Drive Undercliff Drive Path (um) Pond Path (um) Issues Path (um) The Cottage Parklands West Cliff Path FF

Path Westcliff House The Orchard Sinks Path Swimming Pool Path (um) Path (um) The Undercliff Posts Fountain Studio House OLD closed after SPECIAL Path (um) closed ahead Orchard Close PARK ROAD Woody Bay SPECIAL Stone (um) Orchard Dene Sugar Loaf Ridge Path (um) Works Farmhouse Tunnel Stonelands Old Park Highview (Nursery) 71.1m Niton Undercliff Tennis Ground Old Park Hotel Stables The Well House Verwood until further notice Mirables LB Cottages Inglewood until further notice A 3055 Mirables Issues Swimming Pool Woodland Rise A 3055 A 3055 Issues due to land slip Little Westcliff due to land slip (um) Linstead Path Path 88.4m 85.0m Collects Garage Path (um) (um) Cedar 86.2m Spring Sinks Mean High Water Shingle Glen Little El Sub Sta Track Track Path The Gables Weard Track Camping Call (01983) 822440 Beechwood Stables 82.8m Ground Call (01983) 822440 Boulders, Sand and Shingle 91.5m Puckaster UNDERCLIFF DRIVE Sinks Southcliff Corner for further details for further details Badgers Way Southcliff Lodge Mean Low Water Track SIGN B Tidal Pond SIGN A High Croft Wightleaf Yaffles Pine Ridge Camping Grounds Underwood Puckaster Track Squirrels Cottage 78.2m Camping Grounds Issues Filter Bed The Undercliff The Poplar Wood Mount Cleves Sandrock Hillcroft Pole Ash Lodge FW Collects Cottage Amberwood House The Stables Track 85.7m Issues The Undercliff Drain Graytiles W Collects Ashmead ED Bdy Collects SANDROCK ROAD Puckaster House 74.2m Path (um) Boulders Collects El Sub Sta Bamenda Sea Rock Maycroft PUCKASTER LANE Pentire Homend Issues Puckaster Close Camping Ground Path (um)

Sinks Tennis Court

Whispering Winds Casa De Mar Waters End Spreads Seawynds The Issues Buddle Lane Springmead Camellia Cottage Buddle Issues El Tidal Pond Homestead Sub Ponds Mean High Water Spring Sta Uffa's Und Boulders, Sand and Shingle Paddock Cairnmount Cottage Binnel Point Sinks Tidal Ponds Binnel Bay St Catherine's House Issues Sinks Coachman's House ST CATHERINE'S ROAD Coach House PC TCB 59.3m Buddle Inn Puckaster Farm Mean Low Water (PH) Havens Reach Sinks Pucks Cottage High Barn Highfield Track Mean High Water Paddock Victoria Buddle Place Channel Spring Lodge Shelter Vale Barberry St Catherine'sIssues Terrace View Vineyard Hornbeam Cottage Car Park House Path ThaliaBay House IssuesA Boulders, Sand & Shingle Wireless

Undercliff Cottage Cottage Undercliff Drive St Catherines Cottage Seascape

Dock House Luccerne Issues Cottage East Winnowing Puckaster Reeth Lodge West Winnowing Lodge Issues Bass Rock The Old Beverley closed after Chalet Reeth Flats SPECIAL Radio Station Rocks 53.8m

Dock Lane Dock St Lawrence Admiralty CottageTank The Undercliff Path (um) Mean Low Water Binnel Bay until further notice CASTLEHAVEN LANE Issues BLANK OUT Sinks Pond due to land slip Hideaway Spreads

46.1m Sinks Sinks Cliff Call (01983) 822440 Issues Cove

Path (um) EXISTING SIGNS Cottage Knowles Haven Haven Sands 30 Sinks for further details 29.4m SIGN C Swimming Pool Issues Puckaster Cove Sinks Sand Withy Bed Tidal Ponds Castle Sinks Haven Cottage Boulders and Sand Issues Issues Reeth Bay MLW Sinks Castle Haven Issues FB MLW Caravan Site Beach Cottage Castle Haven Tidal Pond Rock, Shingle & Boulders Rock, Shingle & Boulders 10 20Mean High Water 30 40Boulders, Sand and Shingle 50 MLW Mean Low WaterShingle & Coastal Slope Boulders

Mean Low Water Mean Low Water

Path (um)

Coastal Slope Boulders Based upon the Ordinance Survey mapping with permission of the Controller of Her Majesty's Paul Herbert, Service Director, Island Roads Stationery Office. Ξ Crown Copyright Unauthorised reproduction infringes Crown copyright and Island Roads, St. Christopher House, 42 Daish Way, Newport, Isle of Wight, PO30 5XJ may lead to prosecution or civil proceedings Geological Failure Report Red Isle of Wight Council Licence No. 100019229.2008 UNMARKED Project Drawing Title Drawing 1: Undercliff Drive Zone 9: Woodlands, Undercliff Landslip Diversion Rev. Description Initials Date Drive Checked BM IS Date 30/04/14 Approved IS Date Scale Not to scale Revision Classification Contract Sheet No. Drawing Number 1 Sheet x of x 1 of 1 GEOLOGICAL FAILURE REPORT: RED ZONE 9 WOODLANDS

APPENDIX 3: Drawing 2 – Extent of Ground Movement Along Undercliff Drive (2014 Event)

iv Key Landward extent of geological High groundwater failure levels detected Tension cracks

Direction of ground movement Extent of Location of ground beam geotechnical (geotechnical works) works Ground monitoring point

Ground movement detected

Instrument destroyed by ground movement

Drawing 2: Extent of ground Movement along Undercliff Drive GEOLOGICAL FAILURE REPORT: RED ZONE 9 WOODLANDS

APPENDIX 4: Failure Costs Incurred and On-going Costs

v

Undercliff 9

Costs incurred

Item Description Quant Unit Rate Total John Peck Construction Costs

Costs from John Peck Construction for A.J Geotechnical Services Ltd (drillers) abortive cost. The cost was a settlement sum to cover 1 the rig and equipment back to the mainland, payment of hotel 1.00 sum bookings made, loss of profit due to cancellation of works etc. Island Roads agreed sum

2 De-mobilisation of John Peck. Island Roads agreed sumsum 1.00 sum

Site Hoarding as per photos provided in the Geological Failure 3 Report. 1.00 sum

4 Office and Toilet for security team (period 20/02/14 to 31/03/14) 5.00 weeks

5 Gateman (period 20/02/14 to 28/02/14) 1.00 sum

Reports Failure Report from Ramboll (note that hopefully as conditions improve, Ramboll will be able to provide further 6 recommendations, the costs of which will be considered seperately at a later date) 1.00 sum

Site Security Heras fencing (hire from Monday 10th February 2014 to 04th May 7 2014) 22 No panels 12.00 week

8 Visit to maintain fence line and check security 12.00 visit

9 Signage 8.00 No

10 Barriers & cones 1.00 sum

Surveys Weekly Survey costs from Topographical & Engineering Surveys 11 Ltd which commenced 06th March 2014 8.00 week CCTV Cameras

12 CCTV Cameras (cost split two ways between sites) 1.00 sum

Total £ 28,345.15

Ongoing Costs (w/c 05th May 2014 onwards)

Item Description Quant Unit Rate Total Weekly Survey Cost from Topographical & Engineering Surveys Ltd 1 tba week

Weekly Broadband Cost for CCTV cameras (provisional sum) 2 tba week

3 Weekly site visits to check site tba week

4 Heras Fencing Panels in conjunction with permanent hoarding tba week Total tba week 335.75 tba GEOLOGICAL FAILURE REPORT: RED ZONE 9 WOODLANDS

APPENDIX 5: Remediation Options and Approximate Costs

vi

Undercliff Highway Options

Key Access Options:

1. Re-establish Pedestrian Access Only 2. Repair and re-open road with access from one direction only 3. Repair and re-open road 4. Establish new inland access route to properties 5. Construct a temporary vehicle access route 6. Permanent road closure

Access Stabilisation Option Pros Risks Prelim outline Option cost range* No substantial removal of failed Does not address the long term geological material required risk Pathway can be moved further inland Long term loss of vehicle access Self-drill anchors and (north) to reduce requirements for 1 £250k - £500k pedestrian barrier stabilisation of slipped mass Use of flexible footpath surface to Will require regular monitoring, absorb minor movements inspection, and repair Limited impact on environment Relatively quick construction method Will require limited change inland of road route Only limited removal of slipped Location still at risk from overall geological material required failure Will require regular monitoring, Self-drill anchors and inspection, and repair 2 £1m - £2.5m deep wells Discharge of water may require new outfall to sea subject to EA Approval and Discharge consent Limited Working area, special measures may be required for safe access

Reinforced Soil Block Will allow route of road along current Removal of slipped material required, £2m - £4m 2 and Drainage alignment temp works/monitoring needed to reduce

risk of re-activation of slip Drainage helps address overall Discharge of water may require new geological failure mechanism outfall to sea subject to EA Approval and Discharge consent ‘Soft’ facing for the reinforced soil Ongoing monitoring, inspection and works to allow planting maintenance regime required

Reduced risk of geological failure but still not complete removal of risk Limited Working area, special measures may be required for safe access

Drainage and strand anchors help Hard facing not in keeping with address overall geological failure surrounding environment mechanism Hard facing reduces maintenance Discharge of water may require new requirements outfall to sea subject to EA Approval and Discharge consent Limited Working area, special measures Reinforced soil block may be required for safe access with hard facing, 3 The Environmental Impact of the £6m - £10m drainage, strand Permanent Works will require approval anchors from EA and associated agencies Reduced risk of geological failure but still not complete removal of risk Removal of slipped material required, temp works/monitoring needed to reduce risk of re-activation of slip

Provide long term solution which is Significant temporary works required for resistant to increased range of construction access Pile supported road geological failures 3 deck Reduced scope of maintenance Will require cosmetic measures to bring in £12m - £20m required keeping with local environment Can be designed to provide long term Disturbs sub-surface groundwater stabilisation for deep slips but this will environment

have a cost implication Potential for slope failure either side of the structure will need to be considered, potential need for non-piled stabilisation at either end of route Long term monitoring required Provides longer term protection for Return visits will be required to stabilise road and properties emerging failures Reduced quality route pavement can Access for works will be difficult, almost be used certainly roped access Up-slope face Route independent of overall Long term maintenance of rock slope 4 stabilised by bolting geological failure mechanism vegetation will be required £200k - £500k and netting

Provides long term protection with no Rockfalls will still occur therefore upslope measure needed continuing property risk Route independent of overall Protection structure will have a visual Establish rock fall geological failure mechanism impact 4 £300k - £500k protection structure Protection structure will require regular inspection

Low Cost Short Life solution, will require further Less than £100k works in the near future but will require Temporary Road at 5 Low environmental impact Ongoing monitoring of temporary road further Niton End of Failure and slipped zone will be required expenditure in future Permanent Road Low cost and environmental impact No vehicular or footpath access to 6 Closure properties between ‘Woodlands’ and Less than £100k Undercliff Glen Caravan Park’ *Preliminary cost estimate based on cost of comparable schemes and industry data. A more detail cost assessment can be produced following further detailing of options and assessment of length of application.

Pedestrian Safety Barrier Highway containment barrier NOTES

New access road Key Access Options: Original Profile Highway containment barrier 1. Re-establish Pedestrian Access Only Existing road 2. Repair and re-open road with access from one direction Slipped Profile Reinforced Soil Block only Self drill anchors for local face stability 3. Repair and re-open road 4. Establish new inland access route to properties

Self drill anchors for local face stability

Access Option 1 Access Option 2 Deep wells at 6m c/c Self-drill anchors and pedestrian barrier Self-drill anchors and deep wells Remove slipped soil to surface

Deep wells at 6m c/c Access Option 2 Reinforced Soil Block and Drainage

Highway containment barrier

Single lane route Original Profile

Reinforced soil block faced with gabions/ pre-cast units

Access Option 3 Reinforced soil block with hard facing, drainage, strand anchors

Self drill anchors tied to reinforcement

Deep wells at 6m c/c

Strand Anchor Highway slab Highway containment barrier

Lightweight fill Access Option 3 Pile supported road deck

Tie back anchors CFA piled foundations where needed

Rockfall netting & bolting Localised bolting where required Rock shelter Structure

New access road New access road

Existing road Existing road

Access Option 4 Access Option 4 Up-slope face stabilised by bolting and netting Rock fall protection structure

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ISLE OF WIGHT HIGHWAYS PFI UNDERCLIFF DRIVE HIGHWAY STABILISATION OPTIONS FOR REVIEW 61030594/9/SK/600/06 - Document Name