CIRAM CASE STUDY 5: THORNEY ISLAND

CONTENTS

Introduction ................................................................................................................2

Summary of Site Information ......................................................................................3

Summary of Projected Climatic Information ....................................................................... 3

Identification of Risks and Adaptation Measures………………………………………....5

Summary of Key Risks .............................................................................................17

Conclusion…………………………………………………………………………………..18

Glossary of Abbreviations.........................................................................................20

Annex A ...................................................................................................................21

Annex B ...................................................................................................................26

Crown Copyright

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INTRODUCTION

Climate Impacts Risk Assessment Methodology (CIRAM)

1. CIRAM has been developed by Defence Estates (in partnership with specialist

climate risk consultants, Acclimatise) with the aim of assessing potential threats to MOD sites as a result of projected climate change and help maintain each estates operational capability and capacity. The outcomes of CIRAM can inform management planning and decision making e.g. through Integrated Estate Management Plans (IEMPs) and Business Continuity Plans.

2. Additionally under the UK Climate Change Act (2008) and Government

Sustainable Operation of the Government Estate (SOGE) targets, the MOD is required to carry out an assessment of the risks from the impacts of climate change on its critical sites by 2013, and also to report on the development of adaptation plans.

3. As part of the tool’s development, CIRAM process was trialled at five MOD sites. The outcomes and lessons learned from each of these pilots informed the development of CIRAM. This paper reports on Thorney Island, the fifth of the pilot studies and indentifies climate change risks to the establishment’s objectives and critical operational functions as a result of current and future climate conditions, as well as identify the management actions to build resilience.

CIRAM workshop 4. The CIRAM workshop at Thorney Island took place on the 11 Feb 10 and was

split between 5 working sessions, 4 on each climate variable and 1 exploring interactions.

5. Each climate variable working session comprised of:

• A presentation on climate change science, focussing on observed trends and projected impacts to the UK.

• Presentations on the site specific impacts using the latest UK climate projections in each climate variable (temperature, precipitation, storminess and sea level rise) and their interactions.

• The identification, recording and scoring of potential risks to the site (on a risk register).

• The identification of existing and potential risk management options. 6. The interactions session expanded upon risks and management options identified

in each climate variable working session.

Participants 7. The following roles were represented at the workshop:

• Representatives from the military regiments and ATC on site (RHQ 2IC 47 Regt RA, RHQ 2IC 12 Regt RA, 12 RA HQ USA)

• Business continuity

• Estate focal point for Property/Facility management

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• Station Staff Officer

• Site Delivery Manager

• Site Facilities Management

• Contract management RPC representative (PRIDE)

• Sustainable Development and Infrastructure Army advisory team

• HQ Estates Requirement Officer (4 DIV, 2 Bde)

SUMMARY OF SITE INFORMATION

8. Baker Barracks on Thorney Island is home to 12 Regt RA (Close Air Defence

CAD Regiment, 47 Regt RA (Unmanned Aerial Vehicle UAV Regiment) and TA Signals. There is also SFA on the island. The site was first used by the Royal Air Force in 1935 as a fighter station and later a for Coastal Command base during the WWII. In 1984, the site was taken over by the Army.

9. The built estate is made up of three main areas:

Airfield Area: The runways and perimeter tracks are in reasonable condition and used for military driver training.

Technical Area: The technical area in the centre of the island to the west of the main runway is used for the majority of desk and workshop based training on site. It includes former aircraft hangers, ranges and an assault course.

There is also housing and a primary school to the north-west.

West Thorney Village: The village is made up of the officer’s mess, church and service family accommodation. There is also a sailing clubhouse and workshops, with a jetty into Thorney Channel.

The airfield and facilities were constructed for the RAF prior to the WWII. Many of the buildings have been adapted to fit with the needs of the Army. The site was subject to an extensive upgrade (Project Thornwood), as a result of the last Strategic Defence Review.

10. Thorney Island is situated in Chichester Harbour, West Sussex on the South

coast of England. There is one road connecting the mainland with the island. See Annex A for further information.

SUMMARY OF PROJECTED CLIMATIC INFORMATION

11. UKCP09 provides climatic information for the UK (broken down into 25km2) up to

the end of the century. A number of projections are given based on a number of emission scenarios (low, medium and high). For Thorney Island, the high emissions scenario was used. This indicates that:

• Mean summer temperature: By the 2050s it is very likely that the average summer temperature will increase by between +1.4 oC to +5.3 oC. There is a high likelihood that by the 2050s, mean summer temperatures will increase.

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• Number of hot days annually (days above 25oC): By the 2080s (2070 – 2099) and under the medium emissions scenario it is very likely that there will be between 20 hot days in every 9 in 10 years and 90 hot days in every 1 in 10 years in the area around Thorney Island. There is a high likelihood that by the 2080s the frequency and/or length of hot periods will increase.

• Change in winter mean precipitation: By the 2050s it is very likely that winter precipitation will increase by between +1.5% to +44%. There is a high likelihood that by the 2050s the precipitation in winter will increase.

• Change in precipitation on the wettest day in winter: By 2050 it is very likely that the average precipitation on the wettest day in winter will increase by +1.2% to +34.3%. There is a high likelihood that by the 2050s winter precipitation will become more intense.

• Change in summer mean precipitation: By the 2050s it is very likely that summer precipitation will change by between +2.4% to -51%. There is high likelihood that by the 2050s summers will become drier.

• Sea level rise: There is a 90% probability that the sea level will rise by between +11.3cm and +40.4cm (5% and 95% probabilities) by 2050 (against the 1980–1999 baseline). It is likely that coastal flooding around the harbour will increase; this may lead to increased erosion rates and changes in deposition rates.

• Storm surge height: The storm surge height is likely to increase by between 0.2mm and 2 mm by 2050. For a 20 year return period, the linear trend of the skew surge level increases 0.4mm/year with respect to the 1980-1999 baseline. There is a high likelihood that coastal flooding will increase during storms.

See Annex B for further information.

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IDENTIFICATION OF RISKS AND ADAPTATION MEASURES

OBJECTIVES AND SUCCESS CRITERIA THORNEY ISLAND The critical operational functions identified for the establishment are:

• Operating Station infrastructure;

• Delivery of training;

• Essential services/utilities (water supply, power);

• Security of personnel;

• Provision of Support Services (food supply, messes);

• Provision of Service Family Accommodation (SFA). The wider SD/Environmental legislative and policy obligations that could impact on the establishment’s reputation are:

• Minimal impact to the environmentally and ecologically sensitive Chichester Harbour and surrounding Site of Special Scientific Interest (SSSI) areas;

• Contamination avoidance;

• Compliance with all legislative requirements;

• Provide buildings with comfortable interior environment/temperatures.

• Minimise disruption and nuisance to the local community and promote the base as a good neighbour;

• Maximise opportunities for partnership working and community engagement activities;

• Maximise opportunities for the use of local suppliers;

• Compliance with all legislative requirements. Resource performance

• Value for money;

• Low maintenance costs;

• Avoidance of damage costs from flooding event. RISK SCORE = L x I

Likelihood (L): 3= Probable (60%) 2= Possible (30-60%) 1= Remote (<30%)

Impact (I): 3= Major 2= Significant 1= Minor

Sub-objectives:

• To protect health and wellbeing of users

• To increase resilience of assets / building performance and reduce repairing / maintenance / operation costs

• To ensure environmental / sustainability compliance

Overall objective: Identify and increase resilience to climate related risks likely to impact on the operational capacity of the site

M H H

L M H

L L M

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ood

Impact

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CLIMATE VARIABLE A: TEMPERATURE (warmer summers, warmer winters, increased likelihood of heatwaves)

Risk Score (LxI) CLIMATE RELATED RISKS

Current Future EXISTING

MANAGEMENT FUTURE ACTIONS

PROCESS & OWNER

Building design (poor air ventilation and circulation, high solar gain, internal overheating)

Increased risk of thermal discomfort of users in Orderly Room. Reduced working efficiency. Increased risk of room becoming un-operational if maximum temperature legislation is established

3 x 1 3 x 1 Open windows, natural ventilation, desk fans

Consider moving room to different building. Install Solar shading, black-out windows or air-conditioning. Change work hours.

CO, SETL

Increased risk of thermal discomfort of users in hangar offices, reducing working efficiency.

3 x 1 3 x 1 Open windows, natural ventilation, desk fans

Install Solar shading, black-out windows or air-conditioning. Alter working hours.

CO, SETL

Increased risk of thermal discomfort of users in Officers’ Mess due to orientation and high solar gain for 60% of building

3 x 2 3 x 3 Shut curtains, open windows.

Study refurbishment options including climate proofed design.

QM

Increased risk of thermal discomfort of users in the accommodation ‘H and T Blocks (c.1938)’ (only an issue since the refurbishment of the facilities)

3 x 2 3 x 3 Open doors, windows (H&S restrictions)

Investigate and determine why the new design is less climate proofed than previous blocks and consider the possibility of upgrading the blocks. Consider construction of new blocks. If refurbished again then ensure climate-proofed.

QM, SETL

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Increased risk of thermal discomfort of users in the portacabins.

3 x 2 3 x 3 Natural ventilation Consider construction of new blocks that are climate-proofed.

QM

Increased risk of thermal discomfort inside the school. Increased risk of school closure might create the need for childcare provision.

2 x 2 3 x 3 Blinds, natural ventilation, classes held outside.

Provide after school clubs. Provide air conditioning. Engage with LEA over funding.

LEA

Increased risk of shutdowns and operational disruption due to increased risk of overheating/air conditioning failure in IT Systems server room.

1 x 3 3 x 3 Air conditioning with response maintenance contract.

Consider if higher spec system is needed. Engage with DII team.

SETL, DE&S DII IPT.

Increased risk of thermal discomfort inside kitchens.

2 x 1 2 x 1 Extraction system, natural ventilation (windows/doors)

Upgrade system at end of life. Ensure replacement is climate proofed.

QM, SETL

Infrastructure

Increased risk of damage to roads, tarmac from extreme high and low temperatures e.g. freeze/thaw damage

2 x 1 2 x 1 Contract, reactive maintenance.

Monitor damages and reflect issue in new contract when due for renewal.

SETL

Training

Increased risk of Heat Stress - Physical Training levels may be increased due to pre-deployment training for operations

3 x 1 3 x 2 Change routines, Heat Stress Index checks, water coolers.

Study provision of shading for sports pitches. Provide additional cooling in Gym.

PTIs SETL Commanders

Pests & Diseases

Increased risk of health related issues due to potential increase in the number of mosquitoes

2 x 2 3 x 2 Management regime in place.

Monitor. Research Integrated Pest Management Plan.

4 DIV Environmental Health Team SHEF

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Biological & ecological change

Increased risk of habitat and species change in the island (but also surrounding estuary) which may affect SSSI and land use conditions and generate new risks (including reputational)

1 x 1 2 x 2 IRMP, engagement with stakeholders e.g. Natural England, Chichester Harbour Conservancy

Continue engaging with NE and Chichester Harbour Conservancy and review their work/research on climate change for the area. Monitor SSSI conditions. Update IRMP as necessary.

DE LMS. DE PTS. CHC. NE. EH IRMP

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CLIMATE VARIABLE B: PRECIPITATION (drier summers, wetter winters, increased precipitation in wettest days)

Risk Score (LxI)

CLIMATE RELATED RISKS Current Future

EXISTING MANAGEMENT

FUTURE ACTIONS PROCESS & OWNER

Building design (rainwater ingress, flooding, mould)

Increased risk of rainwater ingress in the Bagnold Lodge Compound in between the double glazing windows, making windows heavy and creating H&S risks.

3 x 1 3 x 2 Not currently being managed.

Consider replacing windows and seals.

SETL. RFCA.

Increased risk of rainwater ingress in the Bagnold Lodge Compound through eaves in garages.

3 x 1 3 x 2 Water swept out of garages when necessary.

Consider seals. SETL. RFCA.

Increased risk of flooding in hangars (stores and offices) due to overwhelming of drain pipes which are within the building’s interior. High roof impedes access.

2 x 1 3 x 2 Access restrictions, move equipment to away from water.

Resolve roof and drainage issues. Add to FMP.

SETL, Aquatrine, RPC

Increased risk of mould in Married Quarters due to increased risk of saturated walls (groundwater ingress and rising damp). Increased risk of health problems and damage to kit.

3 x 2 3 x 3 Vacate property, remove paint, treat with chemicals.

Further surveys needed. Longer term solution needed.

DE Ops Housing, MHS

Drainage systems

Increased risk of damage to flap valves which are critical for the drainage of groundwater on the island

2 x 1 2 x 1 Check valves regularly.

Increase checks. Ensure obligations are added to contract.

SETL Aquatrine

Increased risk of surface water flooding from increased risk of overwhelming of drainage systems

2 x 1 2 x 1 Reactive maintenance?

Improve capacity and maintenance. Ensure obligations are added to contract.

Aquatrine

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High water table

Increased risk of groundwater flooding 2 x 1 2 x 1 Check valves regularly.

Increase checks of valves and monitor groundwater levels. Ensure obligations are added to contract.

Aquatrine

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CLIMATE VARIABLE C: STORMINESS (stronger winds, increase in the frequency and intensity of wind storms and wave

storms, increased rate of coastal erosion)

Risk Score (LxI) CLIMATE RELATED RISKS

Current Future EXISTING

MANAGEMENT FUTURE ACTIONS

PROCESS & OWNER

Asset damage

Increased risk of damage to buildings – hangars vulnerable to high winds.

2 x 2 3 x 2 Out of bounds area around debris. Reactive maintenance.

Monitor frequency of repairs. Investigate options to improve design

SETL

Increased risk of damage to Antenna Sites 1 x 3 2 x 3 In-house repairs. Contractors to repair. RQMS. Contractors.

Increased risk of trees causing damage to buildings, block roads/footpaths, health and safety risks.

2 x 1 3 x 2 Tree management Tree management. SETL RPC

Increased risk of damage from increased frequency and intensity of wave storms impacting on the sea defences (breaching, overtopping). Damage is occurring continually and increasing the risk of tidal flooding of the site. Critical.

3 x 1 3 x 3 Cordon off flooded areas. No management of defences.

Repairs and upgrade needed. Targeted upgrades around critical areas. Funding required. Managed retreat possible in SW corner. Full options study required inc cost/benefit analysis. Strategic approach with full stakeholder engagement.

HQ 4 DIV.

Power supply Increased risk of external power supply outages during stormy weather. No backup supplies. Power comes across causeway.

1 x 3 2 x 3 No management actions in place

Reflect in Business Continuity plan. Engage with supplier over supply security. Review renewable energy options.

2 Bde (Energy Advisor)

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CLIMATE VARIABLE D: SEA LEVEL RISE (higher tides, increase in the frequency and intensity storm surges, higher waves,

increased rate of coastal erosion)

Risk Score (LxI) CLIMATE RELATED RISKS

Current Future EXISTING

MANAGEMENT FUTURE ACTIONS

PROCESS & OWNER

Asset damage

Increased risk of damage to the flood defences from higher sea levels (higher tides & higher waves) overtopping the defences. Damage is occurring continually. Critical.

3 x 1 3 x 3 Cordon off flooded areas. No management of defences.

Repairs and upgrade needed. Targeted upgrades around critical areas. Funding required. Managed retreat possible in SW corner. Full options study required inc cost/benefit analysis. Strategic approach with full stakeholder engagement.

HQ 4 DIV LMS

Flooding Increasing risk of tidal flooding to the establishment from high tides and waves overtopping and breaching the flood defences.

3 x 1 3 x 3 Cordon off flooded areas. No current funding to upgrade flood defences.

Repairs and upgrade needed. Targeted upgrades around critical areas. Funding required. Managed retreat possible in SW corner. Full options study required inc cost/benefit analysis. Strategic approach with full stakeholder engagement.

HQ 4 DIV LMS

Increased risk of groundwater flooding due to increased sea levels.

1 x 1 2 x 2 Not currently an issue. Study processes and geology and monitor conditions.

DE LMS

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Coastal erosion Increased rate of coastal erosion increasing the deterioration rate of the sea defences in the south coast of the island and increasing the risk of losing the flood defences.

2 x 1 3 x 2 Not being managed at the moment.

Monitor the rate of coastal erosion and investigate/consider issue when reviewing the IRMP and developing the Flood Defences Full Options Study.

DE LMS HQ 4 DIV

Surrounding environmental damage

Increased risk of sewage pollution form the pumping station due to increased risk of flooding

1 x 3 2 x 3 Reactive. Pumped out with tankers.

Monitor so that pollution risks from system are minimised.

Aquatrine

Increased risk of erosion and lowering of the intertidal foreshore surrounding habitats due to MOD existing flood defences - create reputational risks

2x1 3x2 Engagement with the North Solent Coastal Management forum

Keep engaging with the North Solent Coastal Management Forum and Chichester Harbour Conservancy.

HQ 4 Div LMS

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INTERACTIONS BETWEEN RISKS

Risk Score (LxI) CLIMATE RELATED RISKS

Current Future EXISTING

MANAGEMENT FUTURE ACTIONS

PROCESS & OWNER

Changes in precipitation ↔ Soil conditions ↔ Tree stability

Increased risk of tree instability causing damage to buildings, block roads/footpaths, health and safety risks.

2 x 1 3 x 2 Tree management. Tree management. SETL

High temperatures ↔ Reduced precipitation ↔ Security of water supply

Increased risk of reduced water availability and/or hosepipe bans during drought conditions

- 1 x 3 To date no hosepipe bans have affected the site.

Engage with Aquatrine to ensure security of supply.

Aquatrine

Intense precipitation events ↔ Flooding ↔ Pollution

Increased pollution risks from flooding of interceptors from vehicle washdown areas, petrol, oils and lubricants (POL) points, fuel tanks (underground), MT oil, cookhouse oil etc.

1 x 3 3 x 3 Bunds, underground seals etc. Spillage plan.

Monitoring and maintenance of interceptors. Ensure early warning system and pollution control plan in place.

47 Regt QMT

Intense precipitation ↔ Saturated ground ↔ Groundwater flooding ↔ Surface water flooding ↔ Access road ↔ Deliveries

Increased risk of the access road being flooded by different sources of flooding impeding the access to the establishment for site staff, emergency services, supplies. Critical.

2 x 1 3 x 3 Divert traffic. Control of high water inlet. Options study of flood defences for road, potentially elevate roadway.

DE LMS SETL Southern Water

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Intense precipitation ↔ Saturated Ground ↔ Groundwater flooding ↔ Surface water flooding ↔ High spring tide ↔ Storm

Increased risk of flooding to the establishment

1 x 3 2 x 3 Evacuation Plan in development (OP FALUCA).

Ensure Business Continuity plan is updated.

Regt HQ

Intense precipitation ↔ High water table event followed by cold snap

Increased risk of freezing of surface water on roads within the establishment, causing dangerous conditions that could create risks to the safety of drivers and pedestrians.

1 x 3 1 x 3 Divert and restrict traffic. Monitor conditions. Consider issue in H&S risk assessments

RSM H&S

Higher sea levels ↔ Increased frequency & Intensity waves ↔ Coastal erosion ↔ Damage to flood defences & Coastal footpath

Increased risk of higher sea levels and more frequent and intense wave storms are likely to increase the rate of damage to the flood defences and could increase the rate of coastal erosion. This could increase risk of loosing the public footpath in the south coast of the island with additional reputational risks.

2 x 1 3 x 2 Currently there is no funding available to upgrade the flood defences.

Engage with County Council, Chichester Harbour Conservancy, DE PTS ART, DE LMS. Consider and review in IRMP.

DE LMS SETL

Adaptation actions ↔ Reduced funding ↔ Assets becoming older ↔ Extreme events ↔ Asset damage ↔ Increased maintenance costs

Increased risk of funding not being available to pursue adaptation actions and upgrade assets becoming older, increasing the risk of damage to those assets from climatic events - more maintenance likely to be required.

3 x 3 3 x 3 Currently no funding for adaptation actions.

SETL to monitor and report maintenance and repairing costs of damages from climatic events to D Infra. D Infra to pursue funding.

SETL D Infra

Hot weather ↔ Long period of dry weather ↔ Increased public access ↔ Fire

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Increased risk of fire risk due to increased numbers using the public access footpath during the warm and dry weather (from litter, cigarettes etc) – large areas of scrub/open grassland. Potential issues with access and smoke.

1 x 1 1 x 1 Grounds maintenance. Raise fire awareness around the island. As part of the day-to-day management, advice from the MET Office Fire Severity Index service could be followed.

RSM

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SUMMARY OF KEY RISKS

Temperature

• Increased risk of thermal discomfort (overheating) inside offices accommodation blocks, hangars, orderly room, portacabins.

• Increased risk of thermal discomfort inside the school facilities with increasing

risk of needing child care provision. • Increased risk of problems with the cooling of IT server rooms.

• Increased risk of mosquitoes causing nuisance and health problems to the

users of the establishment.

Precipitation

• Increased risk of water ingress at Bagnold Lodge compound. • Increased risk of flooding in hangars due to drain pipes being overwhelmed. • Increased risk of mould problems in Married Quarters.

• Increased risk of flooding to the only access road disrupting staff travel and

supplies.

Storminess

• Increased risk of wind damage to hangars. • Increased risk of tree damage causing damages to buildings and

roads/footpaths and health and safety risks.

• Increased risk in the frequency and intensity of wave storms damaging the flood defences.

Sea level rise

• Increased risk of high tides and waves overtopping the flood defences, causing further damage to the defences and flooding of the site.

• Increased risk of coastal erosion could exacerbate the existing rate of

damage to the flood defences in the south coast of the island.

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Interactions between risks

• Increased risk of the only access road being flooded due to a combination of intense rainfall events saturating the ground and causing surface water flooding and groundwater flooding.

• Increased risk of flooding to the site form the combination of intense rainfall

events (increased risk of saturated ground & high groundwater levels) and high tides.

• Increased risk of the flood defences being damaged due to a combination of

higher sea levels (higher tides, higher waves) and stormier weather (more intense wave action).

• Restrictions on budgets cause failing of maintenance standards which reduce

the resilience of the assets to weather events. CONCLUSION Summary discussion of key risks and issues 12. Many of the high rated risks relate to thermal discomfort due to overheating in a

range of buildings, some of which are critical to operation of the island. Increased temperatures will further heighten these risks. It was discussed at the CIRAM workshop the possibility of installing air conditioning in some of the buildings but this option is not recommended as it will cause increased energy consumption therefore higher energy bills and greenhouse gas emissions from the site. The most suitable actions to manage this issue will be to explore options to adapt the buildings physically with adaptations such as solar shading. These steps may be necessary should any maximum office temperature legislation be introduced, which would make some of the buildings un-operational.

13. Maintaining access to the island is also a critical risk. Recent heavy precipitation event caused flooding of the single access road on and off the island caused disruption to staff and visitors gaining access to the island. There could be severe consequences should access be cut off completely, with no land access for emergency services or supplies (except by sea or air). Critical staff based on the mainland may be unable to reach the island, which could also affect operational efficiency.

14. The island is subject to continuous geological sinking (as the rest of the South

East of England), increasing sea levels and higher and more intense waves, with many of the sea defences currently experiencing damage and in need of repair. The sea has breached, over-topped and undercut the existing defences, therefore it is recommended a full options study is undertaken to determine the extent of the damage and identify where defences need to be upgraded. There are risks to the perimeter footpath that goes round the island, as parts of it may erode away, forcing the public to stray further into MOD land. The design of any upgrades or new flood defences realigning the defence line need to follow the Planning Policy Statement (PPS) 25 and also the Chichester Conservancy Policy on sea defences.

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15. Another major risk is the combination of high tides and surface water flooding at

the same time, which could leave large areas of the island flooded. It is important that all potential pollutants such as the POL point and sewage pumping station are protected from floodwater to prevent contamination, which could spread to groundwater. Past flooding events have shown this water takes a long time to drain away. Further risks may occur should this water freeze, which could affect health and safety.

16. There are also ecological issues associated with the designated sites surrounding

the island. Future ecosystem change may have adverse affects on SSSI condition, and it will be important to fully engage with stakeholders such as Natural England and Chichester Harbour Conservancy. Any upgrades to the flood defences should ensure environmental impacts are minimized, as there is potential to cause continued erosion and lowering of intertidal foreshore habitats. The island could be affected by changing patterns of bird migration. Climate change may also make conditions more favourable to mosquitoes, and increased management may be needed.

17. Continued budgetary restrictions imply that routine maintenance will increasingly

become prioritised. This is likely to have the effect of the infrastructure becoming more vulnerable to the effects of climate change.

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GLOSSARY OF ABBREVIATIONS

ADMINCON Administrative Control BC Business Continuity BMS Building Management System CAD Close Air Defence CESO Chief Environment and Safety officer CEstO Customer Estate Organisation CIRAM Climate Impact Risk Assessment Methodology CO Commanding Officer DE Defence Estates DE Ops Defence Estates Operations Directorate DE&S Defence Equipment and Support DII Defence Information Infrastructure FM Facilities Manager FMPs Forward Maintenance Plans H&S Health and Safety IEMP Integrated Estate Management Plan IRMP Integrated Rural Management Plan IPT Integrated Project Team LA Local Authority MODPGA MOD Police and Guarding Agency NGEC Next Generation Estate Contracts RPC Regional Prime Contract SETL Site Estate Team Leader SHEF Safety, Heath, Environment and Fire SOGE Sustainable Operations on the Government Estate SSD&C Safety, Sustainable Development and Continuity Directorate STW Sewage Treatment Works TLB Top Level Budget holder UAV Unmanned Aerial Vehicle

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ANNEX A

SITE INFORMATION: THORNEY ISLAND Thorney Island is home to Baker Barracks and West Thorney Service Families Accommodation (SFA). Thorney Island was first used by the Royal Air Force in 1935 as a fighter station and later a for Coastal Command base during the WWII. In 1984, the site was taken over by the Army and is now the home base for two Royal Artillery Regiments. The island is the base for 47th Regiment Royal Artillery a UAV regiment. The regiment is a sub-unit of 1 Arty Bde but is ADMINCON to 2 SE BDE at Shorncliffe, part of 4 Div. The 12th Regt RA is also based on the island, and provides CAD defence protection for 1st (UK) Armoured Division using the High Velocity Missile System (HVM). 47 Regt RA is an air defence regt equipped with High Velocity Missile Self Propelled (HVM SP) STORMER (Fig. 1).

Figure 1 - HVM SP STORMER (Source: Defence Image Database)

The built estate is made up of three main areas:

• Airfield Area: The runways and perimeter tracks is in reasonable condition and used for military driver training;

• Technical Area: The technical area in the centre of the island to the west of

the main runway is used for the majority of offices, garages and workshop based training on site. It includes former aircraft hangers, a range and an

assault course. There is also housing and a primary school to the north-west.

• West Thorney Village: The village is made up of the officer’s mess, church and service families accommodation. There is also a sailing clubhouse and workshops, with a jetty into Thorney Channel.

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The airfield and facilities were constructed for the RAF prior to the WWII. Many of the buildings have been adapted to fit with the needs of the Army. The site was subject to an extensive upgrade (Project Thornwood), as a result of the last Strategic Defence Review.

Figure 2 - Satellite View of Thorney Island (Source: GEODE)

Thorney Island (Fig 2 & 3) is situated in Chichester Harbour, West Sussex on the South coast of England. There is one road connecting the mainland with the island. The island is surrounded by the tidal estuary of Chichester Harbour and is cut off from the mainland by a stretch of water known as the Great Deep, which is protected from the disturbance by the tides by a series of sluices and only partly flushed on each tidal cycle. When the tide turns, the sluice gates open and water flows west to east, flushing the channel. Drainage ditches in the west of the island feed into the harbour, while those in the north of the island enter the Great Deep. There are a range of habitats within Thorney Island, with nearly half covered by grassland, comprising permanent pasture, haymeadow, amenity grassland and rough grassland with scrub. The other large component is the inter-related intertidal, subtidal and coastal grouping, consisting of saltmarsh, mudflat, sand dune and shingle, and representing about one fifth of the holding. The built up and arable areas occupy about 12% and 10% respectively. There are a variety of wetland habitats: saline lagoons, ponds, ditches, streams and reedbeds. Woodland, hedgerows and amenity planting form the other main group of habitats present. There is one tenant farmer farming the land on Thorney Island.

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Figure 3 Map of Thorney Island and surrounding area Environmental issues Designated Nature Conservation Areas Thorney Island lies within Chichester Harbour Site of Special Scientific Interest (SSSI). The site is also internationally designated within Chichester and Langstone Harbour Special Protection Area (SPA) and Ramsar, and Solent Maritime Special Area of Conservation (SAC) for the significant numbers of wintering wildfowl and waders, as well as breeding birds both within the harbour and in the surrounding permanent pasture fields and woodlands. There are several Local Nature Reserves (LNRs) nearby including Eames Farm, Nutborne Marshes and Pilsey Island. Landscape The site lies within Chichester Harbour Area of Outstanding Natural Beauty (AONB). The coast has tidal inlets that lead inland from the harbour mouth via an open water

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pool, around and adjacent to Thorney Island to the A259 road which generally forms the northern boundary of the AONB. The area is also designated as an Amenity Area. Chichester Harbour Conservancy was established by the Chichester Harbour Conservancy Act 1971 with a duty to conserve, maintain and improve the Harbour and the Amenity Area for recreation and leisure, nature conservation and the natural beauty. The Conservancy also acts as the Joint Advisory Committee for the Area of Outstanding Natural Beauty (AONB) and is the Harbour Authority. Archaeology and Cultural Heritage Archaeological data suggests a long human presence on the island from at least the Neolithic continuing to the present day. Little systematic archaeological work has been carried out on the island and the majority of information was gathered during the development of the RAF station during the Second World War.

There are a number of notable buildings on site, including St Nicholas Church, the former Second World War RAF guardroom, HQ and officers’ mess.

Access and Recreation The Chichester Harbour Conservancy estimates that visitor numbers to the Chichester Harbour AONB exceed 1.5 million/year. About 25,000 people use the Harbour for water related activities each year. There is a public footpath surrounding the island and access details can be found on the MOD Access website. Water/Sewage Discharges One of the two main surface water discharge ditches into Emsworth Channel for the technical area drains into the sea north of Marker Point. The other drains into the Great Deeps between the Western Sluice Gate and the main causeway. There is a drain through Flap Valve (FV) 22 which discharges the surface water from most of the Technical Site into the Great Deeps between the causeway and the East sluice gate. There are also a number of ditches and drains carrying surface water run-off from the airfield entering Thorney Channel through FV. The Environment Agency monitors surface water discharge. The Thornham Sewage Works treats the sewerage created by Baker Barracks and the other local communities. The discharge from Thornham Sewage Works is cleaned and then discharged through the Great and Little Deeps reed beds and the Eastern sluice structure. The Great and Little Deeps reed beds act as a filtration system. Land Quality Assessment (LQA) Various LQAs undertaken in 2004 identified the presence of DDT in the environment on Thorney Island but remediation work during 2007 resolved the problem. There are also localised areas of heavy metals, hydrocarbons and organochlorine pesticide contamination arising from waste disposal in the Stanbury Point landfill, on the east coast of the island.

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Aquifer The Baker Barracks site is underlain by the Upper Chalk, a major aquifer. Groundwater currently appears to be of good quality, although it may be subject to saline intrusion. There are no local groundwater abstractions. The drift geology includes marine deposits, low permeability clay soils that appear to hinder migration of contaminants to the chalk from the surface.

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ANNEX B

SUMMARY OF CURRENT AND FUTURE CLIMATIC INFORMATION FOR THORNEY ISLAND UK Climate Projections (UKCP09) Unless otherwise stated the scenarios described below relate to the projected changes by 2050s relative to the 1961 – 1990 baseline and give the projections by season under the ‘high emissions scenario’ from UKCP09 (the UK’s most-up-to date climate change projections). The Emissions scenarios were created by the IPCC (Intergovernmental Panel on Climate Change) as a way of exploring the potential trends in global developments and green house gases (GHG) emissions, as well as the key influential drivers. Temperature a) Observed changes: In South East England, the annual daily mean temperature

has increased by +1.62oC from 1961 to 2006. In summer this it has risen by 1.77oC and in winter by 2.0oC.

b) Projected change in mean summer temperature: By the 2050s it is very likely

that the average summer temperature will increase by between +1.4 oC to +5.3

oC. c) Projected Number of hot days annually (days above 25oC): By the 2080s

(2070 – 2099) and under the medium emissions scenario it is very likely that there will be between 20 hot days (where 25oC is likely to be exceeded every 9 in 10 years) and 90 hot days (where 25 oC is likely to be exceeded every 1 in 10 years) in the area of Thorney Island. Under the 50% probability it is very likely that there will around 76 hot days (where 25oC is likely to be exceeded every 1in 2 years).

d) Projected change in average temperature of the warmest day in summer: By

the 2050s it is very likely that the maximum daily temperatures in summer will increase by between +1.7oC to +7 oC under the high emissions scenario.

e) Projected change in average daily maximum temperatures in summer: It is

very likely that summer average daily maximum temperatures will be between +21 oC and 27 oC. Daily maximum temperatures in summer are projected to increase in all months but the highest temperatures are likely to be reached in July (between 21.4 – 27.8 oC) and August (22.1 – 27.2 oC) as oppose to the current baseline (average for 1971 – 2000) of 20.5 oC in July and 20.7 oC in August.

f) Projected change in mean winter temperature: By the 2050s it is very likely

that winter temperature will increase by between 1.4 oC to 3.8 oC under the high emissions scenario.

g) Projected change in average temperature of the coolest day in winter: By

the 2050s it is very likely that the temperature on the coolest day in winter will increase by between -0.1 oC to +4.1 oC under the high emissions scenario.

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Precipitation a) Observed changes: In SE England the summer precipitation has decreased by

13.1% and winter precipitation has increased by 23.3% from 1961 to 2006. b) Observed changes in humidity: Total annual humidity has decreased by -3.8%

from 1960 – 2006 in SE England based on a linear trend. Summer humidity has decreased by -4.7% and winter humidity has decreased by -3.3%.

h) Projected change in mean summer precipitation: By the 2050s it is very likely

that summer precipitation will change by between +2.4% to -51% .

c) Projected changes in mean winter precipitation: By the 2050s it is very likely

that winter precipitation will increase by between +1.47% to +44%. d) Change in precipitation on the wettest day in winter: By 2050 it is very likely

that the average precipitation on the wettest day in winter will increase by +1.2% to +34.3%.

Sea level rise a) Observed changes in sea temperatures: The average coastal sea-surface

temperature has increased by an average of 0.7 oC around the UK. b) Observed changes in sea levels: The Marine Climate Change Impacts

Partnership has observed rises of 0.55mm/year at Sheerness, Kent, compared with the baseline at Newlyn, Cornwall since 1916.

c) Projected changes: It is very likely that the sea levels will increase by be

between +11.3cm and +40.4cm (5% and 95% probabilities) by the 2050s.

Storms a) Observed changes in storminess: Severe windstorms around the UK have

become more frequent in the past few decades, although not above that seen in the 1920s. Robust projections of changes in storm track are not yet possible.

b) Projected Storm surge height: By the 2050s and under the medium emissions

scenario the estimated increase is of 0.2mms/year for a 20 year return period with respect to the 1980 – 1999 baseline.

CURRENT AND HISTORICAL ISSUES Flooding Thorney Island is located in an area designated as tidal floodplain and according to EA flood data is at high risk of tidal flooding (Figure 12). Thorney Island is covered in the Environment Agency’s (EA) Arun and Western Streams Catchment Flood Management Plan (CFMP). EA policy for this area states that they will keep flood risks under review to ensure the most effective management. The draft North Solent Shoreline Management Plan (SMP), also published by the EA (currently on consultation until the 23 April 2010), states that whilst there is minimal

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coastal erosion risk, an extensive area of MOD land and the single access road are at risk from tidal flooding. The North Solent SMP also indicates that existing flood defences will continue to be maintained by MOD for as long as MOD occupies the site although this will cause continued erosion and lowering of intertidal foreshore habitats that would need to be compensated for elsewhere. But if ownership would change in the future, there would be opportunities for coastal realignment.

Figure 2 - Thorney Island Flood Risk Map (Source: GEODE)

Waves and Tides The coastline of Thorney Island is exposed to the sea on the west (Emsworth Channel), east (Thorney Channel) and south (Southern Coastline). The sea defences are exposed to tidal forces at high water when the sea level rises above the mudflats. The fetch on the East and West sides is estimated at a maximum of 2 km. The Southern Coastline is exposed to waves coming from the English Channel through the shallow mouth of Chichester Harbour

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Geological hazards Information from the British Geological Survey atlas Britain beneath Our Feet shows that there is currently moderate risk of geological hazards in the Thorney Island area. However, climate change may alter the properties of these risks:

• Landslide potential – low to nil

• Swell-shrink potential (subsidence) – significant

• Soluble rocks (solution potential) - low

• Compressibility / Collapsibility potential – moderate

• Running sand potential – moderate

• Groundwater flooding potential – high

• Flooding in the recent geological past - no Climate change may alter the properties of these risks.