Ciram Case Study 5: Thorney Island

Home , Chichester, Eames Farm, Pilsey Island, West Thorney

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

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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 2

• 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 25km 2) 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 o C to +5.3 o C. There is a high likelihood that by the 2050s, mean summer temperatures will increase.

• Number of hot days annually (days above 25 oC): 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.

IDENTIFICATION OF RISKS AND ADAPTATION MEASURES

Overall objective: Su b-objectives: • To protect health and wellbeing of users Identify and increase resilience • To increase resilience of assets / building to climate related risks likely to performance and reduce repairing / impact on the operational maintenance / operation costs capacity of the site • To ensure environmental / sustainability compliance

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

M H H Likelihood (L): Impact (I):

L M H 3= Probable (60%) 3= Major 2= Possible (30-60%) 2= Significant

Likelihood L L M 1= Remote (<30%) 1= Minor

Impact 5

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

Risk Score (LxI) EXISTING PROCESS CLIMATE RELATED RISKS FUTURE ACTIONS Current Future MANAGEMENT & OWNER

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

Increased risk of thermal discomfort of 3 x 1 3 x 1 Open windows, natural Consider moving room to CO, SETL users in Orderly Room. Reduced working ventilation, desk fans different building. efficiency. Increased risk of room Install Solar shading, black-out becoming un-operational if maximum windows or air-conditioning. temperature legislation is established Change work hours. Increased risk of thermal discomfort of 3 x 1 3 x 1 Open windows, natural Install Solar shading, black-out CO, SETL users in hangar offices, reducing working ventilation, desk fans windows or air-conditioning. efficiency. Alter working hours. Increased risk of thermal discomfort of 3 x 2 3 x 3 Shut curtains, open Study refurbishment options QM users in Officers’ Mess due to orientation windows. including climate proofed and high solar gain for 60% of building design. Increased risk of thermal discomfort of 3 x 2 3 x 3 Open doors, windows Investigate and determine why QM, SETL users in the accommodation ‘H and T (H&S restrictions) the new design is less climate Blocks (c.1938)’ (only an issue since the proofed than previous blocks refurbishment of the facilities) and consider the possibility of upgrading the blocks. Consider construction of new blocks. If refurbished again then ensure climate-proofed.

Increased risk of thermal discomfort of 3 x 2 3 x 3 Natural ventilation Consider construction of new QM users in the portacabins. blocks that are climate- proofed. Increased risk of thermal discomfort inside 2 x 2 3 x 3 Blinds, natural ventilation, Prov ide after school clubs. LEA the school. Increased risk of school closure classes held outside. Provide air conditioning. might create the need for childcare Engage with LEA over funding. provision. Increased risk of shutdowns and 1 x 3 3 x 3 Air conditioning with Consider if higher spec system SETL, operational disruption due to increased risk response maintenance is needed. Engage with DII DE&S DII of overheating/air conditioning failure in IT contract. team. IPT. Systems server room. Increased risk of thermal discomfort inside 2 x 1 2 x 1 Extraction system, natural Upgrade system at end of life. QM, SETL kitchens. ventilation Ensure replacement is climate (windows/doors) proofed.

Infrastructure

Increased risk of damage to roads, tarmac 2 x 1 2 x 1 Contract, reactive Monitor damages and reflect SETL from extreme high and low temperatures maintenance. issue in new contract when e.g. freeze/thaw damage due for renewal.

Training

Increased risk of Heat Stress - Physical 3 x 1 3 x 2 Change routines, Heat Study provision of shading for PTIs Training levels may be increased due to Stress Index checks, sports pitches. SETL pre-deployment training for operations water coolers. Provide additional cooling in Commander Gym. s

Pests & Diseases

Increased risk of health related issues due 2 x 2 3 x 2 Management regime in Monitor. 4 DIV to potential increase in the number of place. Research Integrated Pest Environmen mosquitoes Management Plan. tal Health Team SHEF 7

Biological & ecological change

Increased risk of habitat and species 1 x 1 2 x 2 IRMP, engagement with Continue engaging with NE DE LMS. change in the island (but also surrounding stakeholders e.g. Natural and Chichester Harbour DE PTS. estuary) which may affect SSSI and land England, Chichester Conservancy and review their CHC. NE. use conditions and generate new risks Harbour Conservancy work/research on climate EH (including reputational) change for the area. Monitor IRMP SSSI conditions. Update IRMP as necessary.

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

Risk Score (LxI) EXISTING PROCESS CLIMATE RELATED RISKS FUTURE ACTIONS Current Future MANAGEMENT & OWNER

Building design (rainwater ingress, flooding, mould)

Increased risk of rainwater ingress in the 3 x 1 3 x 2 Not currently being Consider replacing windows and SETL. Bagnold Lodge Compound in between the managed. seals. RFCA. double glazing windows, making windows heavy and creating H&S risks. Increased risk of rainwater ingress in the 3 x 1 3 x 2 Water swept out of Consider seals. SETL. Bagnold Lodge Compound through eaves in garages when RFCA. garages. necessary. Increased risk of flooding in hangars (stores 2 x 1 3 x 2 Access restrictions, Resolve roof and drainage issues. SETL, and offices) due to overwhelming of drain move equipment to Add to FMP. Aquatrine, pipes which are within the building’s interior. away from water. RPC High roof impedes access. Increased risk of mould in Married Quarters 3 x 2 3 x 3 Vacate property, Further surveys needed. DE Ops due to increased risk of saturated walls remove paint, treat Longer term solution needed. Housing, (groundwater ingress and rising damp). with chemicals. MHS Increased risk of health problems and damage to kit.

Drainage systems

Increased risk of damage to flap valves which 2 x 1 2 x 1 Check valves Increase checks. SETL are critical for the drainage of groundwater on regularly. Ensure obligations are added to Aquatrine the island contract. Increased risk of surface water flooding from 2 x 1 2 x 1 Reactive Improve capacity and Aquatrine increased risk of overwhelming of drainage maintenance? maintenance. systems Ensure obligations are added to contract.

High water table

Increased risk of groundwater flooding 2 x 1 2 x 1 Check valves Increase checks of valves and Aquatrine regularly. monitor groundwater levels. Ensure obligations are added to contract.

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) EXISTING PROCESS CLIMATE RELATED RISKS FUTURE ACTIONS Current Future MANAGEMENT & OWNER

Asset damage

Increased risk of damage to buildings – 2 x 2 3 x 2 Out of bounds area Monitor frequency of repairs. SETL hangars vulnerable to high winds. around debris. Investigate options to improve Reactive maintenance. design 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 2 x 1 3 x 2 Tree management Tree management. SETL buildings, block roads/footpaths, health and RPC safety risks. 3 x 1 3 x 3 Cordon off flooded areas. Repairs and upgrade needed. HQ 4 DIV. Increased risk of damage from increased No management of Targeted upgrades around frequency and intensity of wave storms defences. critical areas. impacting on the sea defences (breaching, Funding required. overtopping). Damage is occurring Managed retreat possible in continually and increasing the risk of tidal SW corner. flooding of the site. Critical. Full options study required inc cost/benefit analysis. Strategic approach with full stakeholder engagement.

Power supply

Increased risk of external power supply 1 x 3 2 x 3 No management actions Reflect in Business Continuity 2 Bde outages during stormy weather. No backup in place plan. (Energy supplies. Power comes across causeway. Engage with supplier over Advisor) supply security. Review renewable energy options. 11

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) EXISTING PROCESS CLIMATE RELATED RISKS FUTURE ACTIONS Current Future MANAGEMENT & OWNER

Asset damage

Increased risk of damage to the flood 3 x 1 3 x 3 Cordon off flooded areas. Repairs and upgrade needed. HQ 4 DIV defences from higher sea levels (higher tides No management of Targeted upgrades around LMS & higher waves) overtopping the defences. defences. critical areas. Damage is occurring continually. Critical. Funding required. Managed retreat possible in SW corner. Full options study required inc cost/benefit analysis. Strategic approach with full stakeholder engagement.

Flooding

Increasing risk of tidal flooding to the 3 x 1 3 x 3 Cordon off flooded areas. Repairs and upgrade needed. HQ 4 DIV establishment from high tides and waves No current funding to Targeted upgrades around LMS overtopping and breaching the flood upgrade flood defences. critical areas. defences. Funding required. Managed retreat possible in SW corner. Full options study required inc cost/benefit analysis. Strategic approach with full stakeholder engagement. Increased risk of groundwater flooding due to 1 x 1 2 x 2 Not currently an issue. Study processes and geology DE LMS increased sea levels. and monitor conditions.

Coastal erosion

Increased rate of coastal erosion increasing 2 x 1 3 x 2 Not being managed at Monitor the rate of coastal DE LMS the deterioration rate of the sea defences in the moment. erosion and HQ 4 DIV the south coast of the island and increasing investigate/consider issue the risk of losing the flood defences. when reviewing the IRMP and developing the Flood Defences Full Options Study.

Surrounding environmental damage

Increased risk of sewage pollution form the Reactive. Pumped out Monitor so that pollution risks Aquatrine pumping station due to increased risk of 1 x 3 2 x 3 with tankers. from system are minimised. flooding Increased risk of erosion and lowering of the 2x1 3x2 Engagement with the Keep engaging with the North HQ 4 Div intertidal foreshore surrounding habitats due North Solent Coastal Solent Coastal Management LMS to MOD existing flood defences - create Management forum Forum and Chichester reputational risks Harbour Conservancy.

INTERACTIONS BETWEEN RISKS

Risk Score (LxI) EXISTING PROCESS CLIMATE RELATED RISKS FUTURE ACTIONS Current Future MANAGEMENT & OWNER

Changes in precipitation ↔ Soil conditions ↔ Tree stability

Increased risk of tree instability causing 2 x 1 3 x 2 Tree management. Tree management. SETL damage to buildings, block roads/footpaths, health and safety risks.

High temperatures ↔ Reduced precipitation ↔ Security of water supply

Increased risk of reduced water availability - 1 x 3 To date no hosepipe Engage with Aquatrine to Aquatrine and/or hosepipe bans during drought bans have affected the ensure security of supply. conditions site.

Intense precipitation events ↔ Flooding ↔ Pollution

Increased pollution risks from flooding of 1 x 3 3 x 3 Bunds, underground Monitoring and maintenance of 47 Regt interceptors from vehicle washdown areas, seals etc. Spillage plan. interceptors. QMT petrol, oils and lubricants (POL) points, fuel Ensure early warning system tanks (underground), MT oil, cookhouse oil and pollution control plan in etc. place.

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

Increased risk of the access road being 2 x 1 3 x 3 Divert traffic. Control of high water inlet. DE LMS flooded by different sources of flooding Options study of flood SETL impeding the access to the establishment for defences for road, potentially Southern site staff, emergency services, supplies. elevate roadway. Water Critical .

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

Increased risk of flooding to the 1 x 3 2 x 3 Evacuation Plan in Ensure Business Continuity Regt HQ establishment development (OP plan is updated. FALUCA).

Intense precipitation ↔ High water table event followed by cold snap

Increased risk of freezing of surface water on 1 x 3 1 x 3 Divert and restrict traffic. Monitor conditions. RSM roads within the establishment, causing H&S dangerous conditions that could create risks Consider issue in H&S risk to the safety of drivers and pedestrians. assessments

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

Increased risk of higher sea levels and more 2 x 1 3 x 2 Currently there is no Engage with County Council, DE LMS frequent and intense wave storms are likely funding available to Chichester Harbour SETL to increase the rate of damage to the flood upgrade the flood Conservancy, DE PTS ART, defences and could increase the rate of defences. DE LMS. coastal erosion. This could increase risk of Consider and review in IRMP. loosing the public footpath in the south coast of the island with additional reputational risks. Adaptation actions ↔ Reduced funding ↔ Assets becoming older ↔ Extreme events ↔ Asset damage ↔ Increased maintenance costs Increased risk of funding not being available 3 x 3 3 x 3 Currently no funding SETL to monitor and report SETL to pursue adaptation actions and upgrade for adaptation actions. maintenance and repairing D Infra assets becoming older, increasing the risk of costs of damages from climatic damage to those assets from climatic events events to D Infra. D Infra to - more maintenance likely to be required. pursue funding.

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

Increased risk of fire risk due to increased 1 x 1 1 x 1 Grounds maintenance. Raise fire awareness around RSM numbers using the public access footpath the island. during the warm and dry weather (from litter, cigarettes etc) – large areas of As part of the day-to-day scrub/open grassland. Potential issues with management, advice from the access and smoke. MET Office Fire Severity Index service could be followed.

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.

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.

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.

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

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 47 th 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 12 th 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.

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. 22

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

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. 24

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.

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 +1.62 oC from 1961 to 2006. In summer this it has risen by 1.77 oC and in winter by 2.0 oC. 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 25 oC): By the 2080s (2070 – 2099) and under the medium emissions scenario it is very likely that there will be between 20 hot days (where 25 oC 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 25 oC 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 +1.7 oC 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.

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 o C 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 27

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

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.