COASTAL FLOOD RISK THINKING FOR TOMORROW, ACTING TODAY

Transcription

1 COASTAL FLOOD RISK THINKING FOR TOMORROW, ACTING TODAY SUMMARY REPORT November 2006 Entec UK Limited, in association with Risk Management Solutions and Risk & Policy Analysts

2 Disclaimer: The analysis presented in this paper is based on research undertaken by Entec UK Limited, Risk Management Solutions and Risk & Policy Analysts for the Association of British Insurers (together referred to as the author ) and does not necessarily reflect the views of the Association of British Insurers, its member companies or its contributors. Although the author has taken reasonable efforts to ensure the accuracy of the information and analysis in this paper, save where (and to the extent that) it has not taken such reasonable efforts, the author shall not have any liability for any loss or damage arising in connection with the publication or use of this paper or the information in it. ABI, Entec UK Limited, Risk Management Solutions and Risk & Policy Analysts are not authorised for the conduct of investment business (as defined in the Financial Services and Markets Act 2000) and this paper is not intended as, and shall not constitute, investment advice. Copyright: Association of British Insurers, The information may only be used for private or internal use (provided that fair attribution of copyright and authorship is made). This paper shall not be used for commercial purposes (except for internal use, provided that the copyright and any other proprietary notices are not removed). Reproduction in whole or in part, or use for any commercial purpose (save as provided above) requires the prior written approval of the Association of British Insurers and such consent may be withheld or made subject to conditions. ISBN

3 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS 1 ACKNOWLEDGEMENTS An electronic copy of this report, along with the full technical research report containing further details of all methods and results, are available from The Association of British Insurers (ABI) publishes research that explores public policy and other issues relevant to the insurance industry and its customers. Matt Crossman in the Property and Creditor Team at the ABI managed this project and the consultants team was led by Neil Thurston of Entec UK Limited. The ABI commissioned and funded Entec (in collaboration with Risk Management Solutions and Risk & Policy Analysts) to carry out this research. The work was undertaken in partnership with the Environment Agency through the provision of data. However, the report and conclusions belong exclusively to the ABI. The Association of British Insurers All rights reserved. The Environment Agency flood zone mapping reproduced in this report is: based upon information supplied by the Ordnance Survey Licence based on information supplied by the Centre for Ecology and Hydrology NERC based on information supplied by UK Hydrographic Office Crown Copyright Environment Agency copyright and/or database right All rights reserved. The flood mapping reproduced in this report was originally produced to provide an indication of relative flood risk to areas of land and is not detailed enough to relate to individual properties. Some of the information was not prepared to meet the specific requirements of this study and has not been explicitly assessed as suitable for the purposes for which it may have been used in this study. The Environment Agency regularly updates its information and may hold additional relevant information that has not been incorporated in this report. Acknowledgements The project team of Entec UK Limited, Risk Management Solutions and Risk & Policy Analysts would like to acknowledge the assistance of the following organisations: Defra Flood Management Division Halcrow HR Wallingford Proudman Oceanographic Laboratory Environment Agency Hastings Borough Council Met Office Eastern Daily Press (cover picture) Research Partners: RPA

4 2 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS FOREWORD On 31st January 1953, Britain confronted the worst natural disaster in northern Europe for two centuries. Flood water broke through coastal defences on the East Coast in 1200 places; 32,000 people were evacuated from their homes; tragically, 307 people died. A large number of coastal flood defences were built or upgraded in the years following those dramatic events. Today, many of them are reaching the end of their useful lives. But the threats that they face have been multiplied by climate change and are even more powerful than before. Sea levels are already rising at a faster rate than was predicted latest research shows a 3cm rise in the last ten years. Latest estimates from the UK Climate Impacts Programme suggest that the East Coast could see further rises in relative sea levels of 40cm by 2050 and 80cm by At the same time, climate change is making it likely that storm surges will occur more frequently, and that they will be more destructive when they do. The insurance industry has played a major role in recent years in promoting understanding and debate about the effects of climate change in the UK and across the world. We support the growing consensus that tough targets should be set to reduce carbon emissions. We want to see further action to encourage businesses and every individual to play a more active role in tackling this threat. But we also know that some climate change is inevitable; it is already built into our world. Action is needed now to adapt and prepare for its impact. The ABI s Statement of Principles on Flooding and Insurance provides homeowners and businesses in flood risk areas with vital reassurance; insurance will be available provided that the Government maintains its programme of public investment in flood defences. The forthcoming Comprehensive Spending Review must enable this partnership to continue through to But 3-year spending plans are clearly not enough. Britain needs a sustained and prolonged programme of investment in coastal flood defences over a period of at least 25 years. As Sir David King, the Government s Chief Scientist, has argued: We must either invest more in sustainable approaches to flood and coastal management or learn to live with increased flooding. On the cautious basis set out in this research, we estimate that 8 billion more will have to be spent on the East Coast alone. The best time to start is now. Stephen Haddrill Director General Association of British Insurers

5 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS 3 CONTENTS 1. EXECUTIVE SUMMARY AND RECOMMENDATIONS 4 2. OUR APPROACH 6 3. COASTAL FLOODING 9 4. ASSESSING THE REGIONAL THREAT ASSESSING THE LOCAL IMPACT INSURANCE OF FLOOD RISK FUTURE SOCIETY AND MANAGEMENT RESPONSES KEY REFERENCES 47

6 4 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS 1. EXECUTIVE SUMMARY AND RECOMMENDATIONS What would happen to the East Coast of England today if the storm of 1953 was repeated? And what would be its impact when sea levels have risen, as they almost certainly will, by a further 0.4m? This study uses an insurance catastrophe model to examine the effects of a rise in sea levels on flood risk, and to assess the need for further spending on coastal flood defences in eastern England. To aid the analysis, it focuses on five case studies: Kingston-upon-Hull, Great Yarmouth and Lowestoft, Canvey Island and Southend, East London, and Hastings. It also draws on published data about climate change from government and other authoritative sources. Research findings The impact of climate change Climate change will lead to rising sea levels and may increase chances of extreme storm surges in the North Sea. A sea level rise of 0.4m is highly likely by the end of this century and could happen as early as At the same time, levels of protection against flooding are declining along many parts of the East Coast, due in large part to the effects of climate change. By using insurance catastrophe models we can anticipate the likely effects of these changes on levels of flood risk. This is then combined with postcode based property data to estimate the financial impact of storm and flood events. The rising costs of major events Using these modelling techniques, the research calculates that: The number of properties at risk of flooding in eastern England rises by 48% from 270,000 to 404,000 following a rise in sea levels of 0.4m. (This assumes no new building between now and the middle of this century.) Assuming current levels of flood defences in eastern England are not improved, the financial cost of a single major coastal flooding event will rise to between 7.5 billion and 16 billion once sea levels rise by 0.4m. This is a cautious estimate, since it does not include the long-term economic effects of this major level of disruption, nor the impact on essential public services such as hospitals, schools and emergency services. The number of older people living in coastal communities is projected to rise in the first half of this century, particularly those over 75 years old. This is likely to increase the vulnerability of these areas to flood risk, and the human and financial cost of flooding when it occurs. Improving flood defences Investment now in improvements to coastal flood defences could reduce the number of properties at risk from 270,000 to 170,800. A rise in sea levels of 0.4m would then increase this to 287,400 properties, roughly the same as today. Improvements to flood management could reduce the costs of a single major coastal flood event by between 3.7 billion and 6.8 billion.

7 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS 5 Recommendations Increase spending of improving coastal flood defences on the East Coast of England and in the Thames estuary The ABI has put forward specific proposals to the Government for increased spending on flood defences and flood risk management in the three years of the next Comprehensive Spending Review. However, we also now believe that a sustained additional programme of investment is needed in order to meet the threats that are identified in this research paper. Recent studies confirm that the benefits to cost ratio of this investment is around 7:1. The research estimates that the minimum cost of improving coastal flood management to maintain acceptable levels of risk on the East Coast alone would be: Thames Barrier and central London Tidal Thames east of the Barrier Other East Coast communities from Ramsgate to Hull billion billion billion Improve planning and development It is clear from our findings that more effort is needed to ensure that regional planning strategies take account of climate change risks. Current approaches, which are medium-term at best, cannot capture these satisfactorily. Longer-term strategies are needed, looking 50 and 100 years ahead, to ensure that development and infrastructure plans are resilient, and that vulnerable activities are moved over time to safer locations. Government investment in infrastructure and regeneration equally needs to take account of the sustainability of projects in coastal flood risk areas. Investment appraisals should incorporate realistic long-term flood risk assessments, together with the cost of flood risk management measures. The Government s planning guidance (PPS25) is being revised. It is essential that this is used effectively to ensure that, wherever possible, critical infrastructure projects such as hospitals, schools, emergency services and key transport links are not situated in high-risk areas, particularly those facing deep or rapid flooding. Enable insurance to continue to play a positive role The UK is unique in the developed world; protection against the risk of flooding is a standard part of household and business insurance policies. The British insurance industry wants to keep it that way. Following the inland floods of autumn 2000, the insurance industry agreed a Statement of Principles on Flooding and Insurance, committing itself to providing insurance for existing customers if the Government put plans in place to improve flood defences and flood management. Considerable progress has been made. Changing coastal flood risks will, however, lead insurers to keep these commitments under review. The continued availability of cover for flood risk as a standard part of household and business policies will inevitably come under pressure as a result of climate change. Insurers will continue to signal to government and customers where the pressures are becoming unsustainable.

8 6 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS 2. OUR APPROACH The impact of climate change in the UK will be felt most rapidly in coastal areas. There is an urgent need not just to reduce further climate change by limiting greenhouse gas emissions, but also to adapt to existing changing climate risks as well. The recent Foresight Future Flooding study 1 highlighted that if no action is taken, and depending on the rate of climate and socio-economic change, the annual cost of damage in England and Wales due to coastal flooding could increase by between 1.0 billion and 13.5 billion by the end of the century. The proportion of national flood risk attributable to coastal flooding is also projected to rise from about 50% to between 60% and 70% 2. The Government s chief scientist, Sir David King, has argued that..we must either invest more in sustainable approaches to flood and coastal management or learn to live with increased flooding. Sir Nick Stern, the Government s chief economist, has commented that Adaptation is the only response available for the [climate change] impacts that will occur over the next several decades before mitigation measures can have an effect Governments can contribute through long term policies for climate-sensitive public goods, including coastal protection and emergency preparedness. Recent research using satellite measurements shows that global sea levels are increasing faster than had previously been understood, up from 1.8mm per year to around 3.2mm per year. (Figure 2.1). Figure 2.1 Global sea-level rise satellite measurements and IPCC projections Source: The Future Oceans Warming up, Rising High, Turning Sour. German Advisory Council on Global Change. 1 Office for Science and Technology (2004) Foresight Future Flooding available from 2 Hall, J., Sayers, P., Walkden, M., and Panzeri, M (2006) Impacts of climate change on the coastal flood risk in England and Wales: Phil. Trans. Royal Society, A 364 (2006)

9 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS 7 These changes, combined with post-glacial sinking of the land 3 make the low lying coastal areas of England and Wales increasingly vulnerable to the effects of extreme storm surges. But government funding of flood management has remained almost flat since 2005 at a little over 570 million per year and is now falling in real terms. (Figure 2.2.) As a consequence, increases in coastal flood risk will present considerable long-term challenges for government, local authorities, homeowners, businesses and the insurance industry. Figure 2.2 Flood management funding for England in real terms funding increased by 60 million per year million (2005/06) flat cash settlement from CSR / / / / / / / / /11 Financial Year This study examines the likely future development of coastal flood risk due to climate change and the related need for increased investment in flood management to cope with major East Coast storm events. The project complements studies undertaken by government and has focused on likely impacts of extreme storm surge events. It makes use of a catastrophe model employed by the insurance industry to assess exposure and aggregate damage costs. It provides an insurance industry assessment of residential and commercial property losses and reviews the potential social and economic impacts of flooding of vulnerable sites (schools, ambulance/fire services, hospitals) and critical infrastructure (key ports, transport links, refining and energy infrastructure). Areas at risk in England and Wales are shown in Figure 2.3 with the study area and case study locations. 3 Shennan, I and Horton, B (2002) Holocene land- and sea-level changes in Great Britain. Journal of Quaternary Science 17:

10 8 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS Figure 2.3 Coastal and inland flood risk areas of England and Wales

11 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS 9 3. COASTAL FLOODING The risk of coastal flooding along the East Coast of England is influenced by four major factors: (a) (b) (c) (d) rises in relative sea level; North Sea storm surges; local tidal conditions and seabed/shoreline configuration; coastal defences and flood management measures. Climate change will directly influence the first two of these factors and reduce the effectiveness of the last. As a result flood risk will increase in this already vulnerable region. 3.1 Climate change and sea level rise Analysis of long-term tidal records has shown that global sea levels rose by an average of 1-2mm per year during the 20th century. Sea levels are expected to rise faster over the next century, largely as a response to thermal expansion of the oceans and the melting of land ice. One recent estimate suggests that mean global sea level rise is now at 3.2mm per year up from the 1.8mm per year recorded during the 1990s 4. The Government has recently increased the sea level rise allowances for the east of England from 6mm per year to 8.5mm per year at the middle of the century and 15mm per year by the end of the century 5. The regional patterns of relative sea level change are also influenced by land movements (due to adjustment resulting from the last Ice Age) and local patterns of warming. In 2002 the United Kingdom Climate Impacts Programme (UKCIP) published scenarios indicating that a net sea level rise of up to 34cm is possible around the East Coast of England 6 by the middle of the century, increasing to over 60cm above those for the 1961 to 1990 reference period by the end of the century (Table 3.1). Table 3.1 Estimates of Range of Mean Sea Level Change (cm) Relative to 1961 to 1990 Levels Location 2010s-2030s 2040s-2060s 2070s-2090s Kingston on Hull Grimsby, Immingham and Barton-upon-Humber Kings Lynn Great Yarmouth and Lowestoft South Essex East London Note: Values quoted incorporate land movement estimates, uncertainty due to regional effects and a range of emission scenarios (Low and High, UKCIP02). 4 Reported at World Climate Research Programme meeting on Understanding Sea Level Rise and Variability, June Supplementary Note to Operating Authorities Climate Change Impacts. Defra, October Climate change scenarios for the United Kingdom: the UKCIP02 Scientific report -

12 10 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS These estimates have recently been revised as a result of a better understanding of regional land movements and it is now suggested that relative sea level rise on the East Coast could reach more than 42 cm around the middle of the century and nearly 80cm before the end of the century North Sea storm surges Although sea level rise is an important influence on coastal flood risk, storm surges (i.e. abnormally high sea levels) pose the greatest threat. Storm surges are caused by low air pressure which raises the height of the sea, combined with onshore winds which push the sea. Shallow waters, as on the continental shelf, magnify these effects; the shape of the North Sea produces a funnelling effect, concentrating the surge in a decreasing area. The most extreme storm surges occur when these events coincide with particularly high seasonal tides. Significant storm surges which caused widespread damage and disruption along the East Coast occurred in 1901, 1906, 1944, 1953, 1976, 1978, 1982 and On 31st January and 1st February 1953, weather and tidal conditions combined to produce an extreme storm surge, resulting in the worst natural disaster in northern Europe in 200 years. The surge was generated by an intense, rapidly moving, low-pressure weather system which travelled south-eastwards across the North Sea. The surge height reached 2.74m at Southend, 2.97m at King s Lynn and 3.36m in the Netherlands. A subsequent government inquiry into the causes of the floods identified that coastal defences breached in 1,200 different places along the 1,600 km (1,000 miles) of the East Coast of England. In total 307 people died, 647 square kilometres (160,000 acres) of land were flooded, and 24,000 houses were damaged, of which 500 were totally destroyed. Around 200 industrial facilities were also damaged by floodwater. A massive military assistance exercise was mounted to evacuate 32,000 people from the floodwaters, and to repair and stabilise the damaged defences. Whilst central London escaped serious flooding on this occasion, the warning was clear. Nevertheless, it was not until 1982 that the Thames Barrier became operational, planned to last until Storm surges and climate change scenarios Whilst sea level rise is inevitable and relatively well understood, there is still considerable uncertainty around the impact of climate change on extreme storm surges affecting the UK coastline. UKCIP research has highlighted that climate change scenarios may increase the severity of future storm surges along the East Coast. However, the changes are difficult to model and other research has shown increases in different locations. In eastern England, surge heights with a 2% chance of happening in any year, and more than 80% chance of happening during an 80 year lifetime, could increase by over 1 metre 8 (Figure 3.1). 7 Update to estimates of net sea-level change for Great Britain (2006) Climate change scenarios for the United Kingdom: the UKCIP02 Scientific report -

13 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS 11 Figure 3.1 Change in 50-year return period surge height for the 2080s (metres) Source: UKCIP02 Climate Change Scenarios (funded by Defra, produced by Tyndall and Hadley Centres for UKCIP). The same research also showed that 1.5 metre surge heights at Immingham, currently expected once every 120 years (i.e. less than 1% chance of happening in any one year and just over 50% chance of happening during an 80 year lifetime) could occur once every seven years by the end of the century. That equates to 14% chance of happening in any year or more than 99.9% chance of happening in an 80 year lifetime. (Figure 3.2). Figure 3.2 Extreme High Water Return Period Curves for Immingham 3.0 Water Level (m) Increasing frequency Increasing magnitude Return Period (yr) Present Future (2080s) Source: UKCIP02 Climate Change Scenarios (funded by Defra, produced by Tyndall and Hadley Centres for UKCIP). Similar analysis for the Thames Estuary has indicated that, under present climate conditions, a 1.45 metre surge has a 2% chance of occurring in any year but that this same surge height

14 12 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS is expected to have a 50% chance of occurring in any year by the 2080s under credible climate change scenarios Modelling storm surge events along the East Coast Insurers use catastrophe models to assess their potential exposure to catastrophic loss and to determine risk mitigation strategies, including the need for reinsurance or other capital requirements. These models calculate the costs of storm or earthquake damage from events of different frequencies and severity. This study used the Risk Management Solutions (RMS) storm surge model 10 to assess the current and future impacts of coastal flooding along the East Coast. The model calculates the effects of changes in relative sea and land heights and in the vulnerability, likelihood of failure or overtopping of individual defences along sections of the coastline 11. These changes influence how much water passes through the coastal defences for a given storm surge scenario. The model can also be adapted to reflect changes in relative sea level and the characteristics of the wind driven surges. By combining the outputs of this modelling with postcode-based property data, the values of commercial and residential exposure can be mapped. This allows losses to be estimated for the modelled storm event. 9 Jason Lowe, Hadley Centre, Met Office, pers. comms. 10 This model covers an area running from the Holderness coastline (East Yorkshire) to Deal in Kent, and has been developed as part of the wider RMS European windstorm catastrophe model. It is used by over 70 insurance companies 11 Muir-Wood, R, Drayton, M, Berger, A, Burgess, P and Wright, T (2005) Catastrophe loss modelling of storm surge flood risk in eastern England. Phil. Trans, R. Soc A (2005) 363,

15 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS ASSESSING THE REGIONAL THREAT Storm surge modelling Using the RMS model, we investigated three storm scenarios in order to understand the likely impact of rising sea levels. These were: 1953 event a repeat of the major 1953 storm surge event ( year return period) concentrated on the Norfolk, Suffolk and Essex coastlines; Humber event a year return period event concentrated on the Humber estuary; Thames event a year return period event concentrated on the Thames estuary. These events have a 27-33% chance of occurring at least once within an 80-year lifetime or 33-40% within a 100-year asset life of much coastal infrastructure. Many rating and regulatory agencies use events of this frequency to assess the ability of insurance companies to continue to trade when a relatively infrequent but high impact event occurs. The above probabilities all relate to the current climate, and will increase if climate change increases the likelihood of extreme events. The modelling did not alter any characteristics of the storm surges themselves, merely the base sea level. The magnitude of the surge for the three storm scenarios at different locations within the study area is shown in Figure 4.1. The larger circles indicate more extreme conditions at the different locations. Although the type of event modelled is rare, with an annual probability of around 0.5%, the consequences could be catastrophic. As the above figures show, in the medium to long term the likelihood of this type of event occurring increases to a significant figure. Risk is often defined as probability multiplied by consequence and government and stakeholders, including the insurance industry, are responsible for managing the risk. This study provides insight into the consequences of some possible extreme flood events.

16 14 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS Figure 4.1 Magnitude of modelled storm surge events and maximum extent of flooding under existing conditions For each storm surge scenario, four individual models were generated. These were a baseline model (i.e. the event occurring under existing sea level conditions) and three future models with increases in mean sea level of 0.1m, 0.2m and 0.4m. A sea level rise of 0.4m is highly likely by the end of this century and could happen as early as 2040 (Section 3.1). To investigate the benefits of better flood risk management (such as improved coastal defences, flood resistant and resilient buildings, tougher planning policies and land-use change or managed coastal realignment) each of the storm surge models was re-run using enhanced flood protection levels.

17 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS 15 These were: rural areas defended to a minimum 1:50 year Standard of Protection (SoP); small towns defended to a minimum 1:200 year SoP; larger towns defended to a minimum 1:500 year SoP; strategically important areas such as the Thames Estuary defended to 1:10,000 year SoP. All of these standards of protection relate to existing conditions and will be reduced by sea level rise. These changes broadly replicate the highest ( World Markets ) flood protection targets used in the Foresight Future Flooding study. 4.2 Assessing financial and social costs We have assessed the number of properties at risk from flooding, direct financial losses arising from damage to these properties, and indirect financial losses. Indirect losses include road traffic and railway disruption, agricultural losses and emergency response costs. These were found to be equivalent to around 50% of total direct property damage in the flooding during Autumn The impact on critical infrastructure, including ambulance, fire and police stations, hospitals and GPs surgeries, and schools, was also assessed. All of the regional calculations have been undertaken using the following assumptions: residential and commercial loss values were generated using 2005 property locations with no allowance made for future population or housing growth; and all costs were evaluated using present day values. Details of the datasets and analysis methods used are provided in the study s technical report. 4.3 Residential and commercial property Impact under current flood protection levels At present, around 270,000 properties (236,500 residential and 33,500 commercial properties) are located within the maximum flood extent of the three storm surge events that we modelled. Many of these properties face a relatively low likelihood of being flooded (Figure 4.2). However, since risk reflects both the probability of an event occurring and the consequences if it does, the high number of properties (around 1% of total UK housing stock) gives considerable cause for concern. The number of properties at risk increases by 48% to over 404,000 (352,800 residential and 51,200 commercial) following a rise in sea level of just 0.4m. Despite the relatively low probability of flooding affecting many of these additional properties, the increased proportion of national housing stock affected is significant. It is equivalent to about three quarters of the additional housing the Government is seeking to build in the four Growth Areas planned for south and eastern England.

18 16 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS Figure 4.2 (a) Maximum extent of flooding and affected critical infrastructure today

19 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS 17 (b) Increased extent and impact of flooding following 0.4m sea level rise

20 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS 18 (c) Effect of improved defences in limiting flooding with 0.4m sea level rise

21 Please open to view all three maps.

22 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS 20 The increase in flood risk varies along the East Coast and some locations will have much higher increases in properties caught within the extended coastal floodplain. The number of properties affected in Essex would double; affected properties in Norfolk would increase by 77%. Effectiveness of improved flood protection The number of properties currently at risk of coastal flooding from one or more of the three storm events reduces from 270,000 to 170,800 (148,700 residential and 22,100 commercial) if the standard of coastal defences is improved (Section 4.1). There is a marked reduction in the number of properties facing significant flood risk. Properly planned improvements in flood protection could also reduce the impact of flooding by limiting the depth of flooding and reducing the speed of water flows. In 1953 many houses were severely damaged by deep and fast flooding. However, the offsetting effects of a 0.4m sea level rise result in increased numbers of properties within the maximum floodplain. The total of 287,400 (250,300 residential and 37,100 commercial) is broadly in line with current risk levels at many locations. 4.4 Financial losses Impact under current flood protection levels The total financial losses for the storm surge events with existing sea level varies from 2.5 billion to 6.2 billion (at today s prices) (Figure 4.3). Figure 4.3 Financial losses existing levels of protection 18 billion event Humber event Thames event Existing Present Day Present Day Sea level rise (m) Sea level rise (m) Sea level rise (m)

23 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS 21 A high percentage of these losses would occur in communities with current standards of protection between 1 in years (1% and 0.5% annual probability). These include several smaller towns along the East Coast. Losses will rise substantially to between 7.8 billion and 16 billion (at today s prices) as a result of 0.4m sea level rise. The increase in total damages results from both increased probability and depth of flooding within vulnerable areas and in strategic areas such as South Essex and East London. These estimates do not capture the full range of costs, particularly the regional economic effects which could result from widespread damage leading to abandonment and migration. Effectiveness of improved flood protection Losses at current sea levels would be reduced to between 1.3 billion and 3.4 billion (at today s prices) following improvements to coastal defences. That is, the cost of damages would be less than half those expected under current protection levels (Table 4.1 and Figure 4.4). In addition, the total benefits accruing to these improvements would include the cost of damage avoided completely in less extreme but more frequent storm surges. Current investments in flood and coastal management typically give a benefit-cost ratio of 7:1, much higher than for other public sector capital investments 12. Table 4.1 Benefits of defence upgrades for a single storm surge event Savings billion saved due to enhanced flood management measures 1953 event Humber event Thames event Existing sea level m sea level rise m sea level rise m sea level rise Flood and Coastal Erosion Risk Management ZBR - 41st Defra Flood and Coastal Management Conference July 2006

24 22 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS Figure 4.4 Financial losses enhanced flood management measures 18 billion event Humber event Thames event Existing Existing Existing Sea level rise (m) Sea level rise (m) Sea level rise (m) Direct and indirect losses Loss reduction Larger coastal towns such as Great Yarmouth and Lowestoft benefit particularly from improvements in protection. These coastal communities are currently protected to standards of between 1 in 100 to 200 years (0.5 and 1% annual probability). However even with improved flood management measures, financial losses still increase to as much as 9.2 billion (at today s prices) with 0.4m sea level rise (Figure 4.4). 4.5 Key infrastructure The capacity of coastal communities to respond and recover from a major storm surge is closely related to the vulnerability of key infrastructure located in coastal floodplains. The systemic effects of damage to infrastructure were graphically demonstrated in the floods which hit the Carlisle area in January 2005, resulting in over 3,500 homes (6,000 residents) being flooded. Failure of critical infrastructure, particularly the main electricity sub-station, hampered early responses and affected additional homes and businesses. Many of the main road routes within the town were inaccessible and the Civic Centre, main police and fire stations and bus station were completely flooded to depths over 0.5m. The Carlisle floods highlighted the regional and national consequences of a major flood event. This included the need for external emergency support, prolonged reinstatement of badly damaged homes (over 6 18 months) and long term business continuity and community issues. These effects were seen on a greater scale in New Orleans following Hurricane Katrina. Just as in Louisiana, large scale flooding on the East Coast of England, affecting up to 100 times the number of homes flooded in Carlisle, would have impacts far beyond the immediate physical damage.

25 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS 23 People whose homes were directly affected would need to be relocated most likely a considerable distance from their community and place of work. Disruption to transport and major energy infrastructure (oil and gas supplies) would also have regional and national consequences. It is likely that a significant proportion of the businesses within the region would be unable to operate normally whether or not they were directly flooded. Several of the UK s most important ports are located on the East Coast (Felixstowe, Harwich and Tilbury together handle more than half of the UK s container traffic) and their operation would almost certainly be disrupted through immediate damage and, perhaps more importantly, the prolonged repairs to road and rail links (including some of the UK s busiest and most congested) and to warehousing in the immediate hinterland. Similarly, much of the UK s chemical industry clustered around the Humber would be affected, with potentially costly and extremely long-term impacts if hazardous materials escaped. The natural environment could take many years to recover and tourism in a wider part of the region could be badly affected by the direct and indirect impacts of flooding. The Carlisle floods also highlighted the need for close working and training between and within local authorities, emergency services and central government departments, to ensure that the response is effective and long term. Whilst recent legislation 13 has put in place the necessary structures, procedures and planning to deal with such civil emergencies, nothing on this scale has been experienced in the UK since the 1953 floods. Impact under current flood protection levels Under current flood protection levels, the number of key service buildings within the maximum flood extent of the three storm events is 1,474 today, rising to 2,156 following a sea level rise of 0.4m (Figure 4.2). The immediate response to a storm surge affecting the East Coast today could be significantly hampered as around 15% of fire and ambulance stations within the affected local authorities are located in the maximum flood extent of the storm surges. Major damage to a large number of these sites would restrict the emergency services ability to conduct search and rescue, and evacuation tasks. The response would be hampered further by the fact that around 40% of electricity sub-stations and 15% petrol stations are also at risk. The impact upon local communities will also be affected since 12% of community halls and leisure centres (typically used as evacuation centres), hospitals, health centres and schools within the affected local authority boundaries are located in flood risk areas. Major damage to these facilities would clearly influence the long-term recovery of these areas. 13 Civil Contingencies Act, 2003

26 24 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS Effectiveness of flood protection Improved coastal defences would protect a greater number of these key facilities, returning risk to levels roughly equivalent to those of today, even after 0.4m of sea level rise. However, the systemic impacts remain significant, suggesting that planning for emergency and critical infrastructure needs to move these to less vulnerable locations over time (Figure 4.2). Although many of these assets are likely to be difficult to relocate (due to land availability, social considerations and infrastructure costs), the Autumn 2000 and Carlisle floods highlighted the importance of siting these types of facilities in locations that would enable them both to respond quickly to a flood and to aid long-term recovery following an event. This will require looking beyond the traditional 20 year planning horizon. The effectiveness of long term strategies depends on the development and implementation of properly considered Regional Planning Guidance, Strategic Flood Risk Assessments, Local Development Frameworks and government planning policies at all levels of central and local government. 4.6 Table 4.2 Enhanced coastal flood management costs and benefits Based on data from recent flood management schemes on the East Coast, we estimate that the benefits described above could be delivered through investment in flood defence of between billion. These calculations cover construction costs only (excluding land purchase costs, long term maintenance, compensation for environmental impacts and other costs) at current prices. Cost of defence upgrades to enhanced standard Current standard of protection (SoP) New Standard of Protection (SoP) Cost ( billion) Less than 1:50 SoP No action 0 1:50-1:200 SoP Upgrade to 1:200 SoP :200-1:500 SoP Upgrade to 1:500 SoP :1000 SoP Upgrade to 1:10,000 SoP Total Around billion needs to be invested to deliver the modelled improvements in the eastern Thames Estuary (urban areas to the east of the Thames barrier as far as South Essex) and a further billion is needed for the parts of the East Coast within the study area where improved defences are likely to be justified. Preliminary estimates 14 of the cost of providing continuing protection to the Thames estuary are around 4-6 billion. This sum includes the barrier and associated gates as well as defences in central London to the west of the barrier. The combined costs of providing this improved protection to London and the regional coastal improvements on much of the East Coast total billion (Table 4.3). 14 Thames Gateway and Flood Risk Management A Preliminary Assessment, Environment Agency, 2003

27 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS 25 Table 4.3 Combined costs of improved East Coast flood protection Thames Barrier and central London Tidal Thames downstream of the barrier Remaining East Coast (Ramsgate to Hull) Total billion billion billion billion Capital spending on flood and coastal erosion risk management improvements is currently around 270 million per year. If this remained constant in cash terms it would take more than 40 years to deliver these improvements at the lower cost estimate, based on 6% construction cost inflation without any provision for any other flood or coastal protection elsewhere in England. Realistically it would take a minimum of years to deliver this scale of coastal defence improvements. Given that sea level rises of 0.4m could be experienced as early as the 2040s, and that risk levels will rise significantly in advance of this, action needs to be taken now to start on this strategic programme. In order to do this, sustained real term year on year increases in flood management spending will be needed each year over the next 20 years, starting with a 60 million year on year increase during the next Spending Review period (Figure 4.5).

28 2006/ /19 26 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS Figure 4.5 Flood management expenditure profile to deliver enhanced protection Assumes improvements inflation = 6% per year, other activities inflation = 3% per year Total flood management funding increasing by 60 million year on year 1400 million Additional investment to deliver enhanced East Coast protection by 2030s Additional investment required for other activities Existing spend on flood management / / / / / / / / / / / / / / / / / / / / / /30 Financial year

29 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS Table 5.1 ASSESSING THE LOCAL IMPACT Profiles of case study areas A detailed analysis of current and future coastal flood risk has been conducted within five case study areas along the East and South coast of England. This has been designed to complement the regional analysis and highlight, in more detail, the likely impacts of major storm surge events. This includes indirect flood losses (transport and business disruption), social impacts and environmental consequences of a major storm surge event. The case study locations (Figure 2.3) are described in more detail in the technical report. Case study areas No. Area 1 Kingston-Upon-Hull, Humberside 2 Great Yarmouth and Lowestoft, Norfolk 3 Canvey Island and Southend, Essex 4 East London, including Barking Riverside and Thamesmead 5 Hastings, Kent Current standard of protection (SoP) 90% of defences designed to protect to 1:200 year SoP Standard defences variable between 1:42 and 1:500 SoP Urban areas currently protected to 1:1000 SoP. Condition status of defences currently unknown Urban areas currently protected to 1:1000 SoP. Condition status of defences currently unknown Current defences considered insufficient. New plans in place are designed to offer protection for the 1 in 50 year storm event against overtopping and the 1 in 200 year storm event against breach Vulnerability of the area Very large urban area located on coastal floodplain. Significant area of property and infrastructure protected by existing flood defences. However defences variable in quality/ condition and subject to ongoing programme of maintenance and upgrade, Important regional and tourist town, and hub of important infrastructure routes. Great Yarmouth is currently protected by existing coastal defences but the current condition and status is variable. Canvey Island Large area of residential property vulnerable to coastal flooding. Previous history of severe property losses and loss of life (1953 storm surge event). Southend Some areas vulnerable to coastal flooding and focus area of new development as part of Thames Gateway growth area. Very large urban area located on tidal floodplain of the River Thames. Significant area of property and infrastructure protected by high grade flood defences. This area is also a focus of concentrated future development as part of Thames Gateway development. An important regional centre along the south coast, dominated by a combination of tourism related developments (e.g. hotels and attractions) and residential properties. The first four of these case studies have been evaluated using the storm surge models. The Hastings case study is not covered by the RMS storm surge model and has been evaluated using a variety of additional data sources. 5.2 Local impacts of a major storm surge For each case study, a profile of the likely financial, social and environmental consequences associated with a major storm surge has been developed. These are outlined in the following pages. Further details of the methods used to integrate the modelled flood depth and probability data, and hence derive the expected numbers of properties at risk and total financial losses are outlined in the study s full technical report.

30 28 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS Kingston-upon-Hull and Humber Estuary A major storm surge with a 0.5% annual probability could affect up to 66,200 homes and commercial properties under current climatic and defence conditions. However, existing flood defences would limit major flooding to around 4,000 properties and flood losses of 266 million, broadly comparable to the flooding in Carlisle in Many of the properties which might be affected are located in areas of Hull and Barton-upon-Humber with a relatively low likelihood of flooding (0-25% chance of flooding during the modelled event). During a major event it is likely that railway links between Hull, North Ferriby, Immingham, Grimsby and Barton-upon-Humber would be disrupted. Access would also be severed to the RNLI station at Spurn Head, Hull bus station, and Humber docks and ferries would be disrupted. The lack of access to and from Hull, Immingham and Barton-upon-Humber would directly affect employees, tourists and shoppers, who would be unable to get into/around major conurbations, business districts, hotels or shopping centres, or to deal with flooding in their homes. A major event would also restrict access to west and east Hull, Immingham, Bartonupon-Humber and Hedon from the south for ambulance, fire and police services. This could hamper potential evacuation as well as search and rescue efforts and hence increase the social consequences of a major event. An increase in mean sea level of 0.4m would increase the estimated number of properties affected by significant flooding to 19,100 and overall financial losses to 1.4 billion. This is an overall increase in flood losses of 440% from the present day, assuming no major changes in the current levels of flood protection. A future storm surge event would be characterised by greater depth of flooding and loss of access to many essential services. It would also increase the number of people affected and the likely need for large scale evacuation. The scale of the event would result in long term impacts upon community fabric and social cohesion in what is already the ninth most deprived local authority district out of 354 in England. The increased extent and depth of flooding would affect more transport routes (including potential flooding on parts of the B1445 and A1033, A1173, A1077, the railway link for Bartonupon-Humber and increased risk of flooding to Brough British Aerospace Airport). A major flood event would also have increased implications for nationally important ecological (SSSIs) and recreation features located on the Humber estuary. Business could be severely affected even if not directly flooded - the local port facilities handle a significant proportion of trade between the UK and Europe and include specialist chemical handling facilities, vital to the chemical industry in the surrounding area. The fishing docks and processing industry could be severely affected.

31 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS 29 Figure 5.1 Kingston-upon-Hull flood extent and key sites at risk

32 30 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS Great Yarmouth and Lowestoft A major storm surge with an annual probability of about 0.5% could affect up to 3,900 homes and commercial properties under current climatic and defence conditions. However, existing flood defences would limit major flooding to around 950 properties and flood losses of 62 million. Many of the properties potentially affected would be located in areas of Lowestoft with a less than 20% chance of flooding from the event. No flooding would be expected in Great Yarmouth under current climate and defence conditions. A future storm surge event would result in serious disruption to local routes within Lowestoft and to main feeder roads, limiting access from outside the immediate locality. Key links which could be affected include the A1117, A146 and A12, severance of links between north and south Lowestoft, and flooding of the railway line linking Lowestoft to Norwich and Ipswich. The area s ports would also be disrupted and this would have wider impacts on fishing and offshore energy activity in the North Sea as well as the economies of Norfolk and Suffolk. In addition, there would be flooding to large areas of conservation importance within the Norfolk and Suffolk Broads, affecting tourist industries. Flooding could sever links within the urban areas and cause problems for emergency services including access to hospitals, police and fire stations. Sea level rise of 0.4m would increase the estimated number of properties affected by significant flooding to 17,600 and overall financial losses to 578 million. This represents an increase of 830% from the present day, assuming no major changes in the current levels of flood protection. The areas most at risk would be Lowestoft and surrounding marshes (around 80-90% likelihood of flooding); central Great Yarmouth (30-50% likelihood of flooding), and the north and west of Great Yarmouth (20-40% likelihood of flooding). A future event would increase the extent and depth of flooding and hence increase possible transport disruption including flooding on parts of the A12, A47, A1064 and the main Great Yarmouth railway station and railway line to Norwich. A future flood event would also have increased implications for the local tourist industry (including impacts upon guest houses, hotels and tourist facilities), flooding of the local stadium and racecourse. Deeper, more prolonged flooding would cause increased disruption of heliports, restricting evacuation capabilities. Major flooding could result in large numbers of people having to move out of their homes (probably for extended periods), imposing additional costs in the east of England s second most deprived local authority area. In addition, Great Yarmouth and the surrounding areas are important holiday centres. They make a significant contribution to the wealth of the area and any reduction in tourists caused by real or perceived damage to recreational infrastructure and services would have wider impacts on the surrounding area.

33 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS 31 Figure 5.2 Great Yarmouth and Lowestoft flood extent and key sites at risk

34 32 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS South Essex A major storm surge with a 0.5% annual probability could affect up to 7,400 residential and commercial properties under current climatic and defence conditions. However, existing flood defences would probably limit significant flooding to around 1,400 properties and flood losses to 86 million. Many of these properties would be located in areas of Southend and Shoeburyness with a less than 20% chance of flooding from the event (including the aquarium and associated commercial properties). Due to the high current standards of protection, no significant flooding is anticipated for Canvey Island, an area which was very badly affected during the 1953 storm surge event. A major storm surge of this scale could lead to disruption of the railway line between Southend and Shoeburyness and potentially at Hadleigh Marsh a major route to and from London for commuters. Flooding of the main coast road (B1016) would lead to severance of links to the west from Shoeburyness and eastern Southend, with significant implications for residents and business locally. A number of key sites are located within the potential flood risk areas, including the main hospital in Shoeburyness, gas supply equipment in Shoeburyness and four primary schools. As shown in the Carlisle floods of 2005, reduction of flood risk for these locations is an important consideration for future flood management policies. Following 0.4m sea level rise the number of properties affected by significant flooding would increase to 24,200 and overall financial losses to 336 million. This is an increase of 290%, assuming no major changes in the current levels of flood protection. The areas at highest risk would be the eastern part of Southend and Shoeburyness (30-50% likelihood of flooding). It is possible that Canvey Island would be flooded but the likelihood of major inundation would be less than 10% in the events modelled here. The likelihood of flooding of the access routes to and from Canvey Island increases following sea level rise. Access is currently only possible by two roads (A130 and B1006), both of which are connected to the same roundabout. Any disruption to these routes would hamper evacuation and severely limit access to the industrial areas on Canvey Island, including potential disruption to gas terminals and oil storage depots. This would have significant implications for the national economy since Canvey Island is one of the main gas distribution centres for the UK.

35 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS 33 Figure 5.3 South Essex flood extent and key sites at risk

36 34 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS East London A major storm surge with a 0.5% annual probability could affect up to 22,500 homes and commercial properties under current climatic and defence conditions. However, existing flood defences would probably limit significant flooding to only 340 properties and losses to around 25 million. Most of East London would be very unlikely to flood but there is a small likelihood of localised flooding in low lying areas of Kent Thameside and Gravesend. The low number of properties affected reflects the high standard of protection (currently about 0.1% annual probability of flooding) within this area. Following 0.4m increase in sea level the number of properties affected by significant flooding would increase to about 2,300 and overall financial losses to 195 million. This is an increase in risk of 680%, assuming no major changes in the current levels of flood protection. Although losses are still relatively small even after sea level rise, the frequency of major storm surges may also increase (although this has not been quantified as part of the current study) with major storms potentially occurring times more often by the end of the century. This means that the likelihood of a larger storm surge (i.e. greater than 0.5% annual probability) affecting East London will also increase. This area contains around 140,000 existing homes, with plans for around 120,000 new homes by 2016, and a large concentration of commercial facilities, including high tech industry, oil and gas storage facilities and industrial premises. There is a major car factory at Dagenham, power stations at West Thurrock and Dagenham, and numerous electricity sub-stations and sewage treatment works and pumping stations. Given the high standard of protection and nature of existing defences it is likely that any defence failure would result in rapid flooding with fast flowing water, posing considerable risk to life for those living and working in the area. There are a variety of major road and railway routes which could be disrupted by a large coastal flood. This would have direct impacts on key business and trade activities in London. The Port of London, one of the UK s largest ports, which handles around 10% of all UK trade, serves 30% of the UK s population and creates 2.7 billion of revenue per annum. Loss of commuter access for key city workers would disrupt financial institutions and markets and major high tech industrial, computing and service industries. A major event would also have knock on impacts for suppliers and distributors for specific services. The residual risk for the East London area is very high and clearly warrants an exceptional standard of flood management protection.

37 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS 35 Figure 5.4 East London flood extent and key sites at risk

38 36 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS Hastings Hastings is served by good transport links provided by the A259 running east to west across the frontage and the A21 running north / south. The area is also served by rail links and improving links to London has been identified as an area for development. The Environment Agency Flood Map identifies risk seaward of the promenade and to the west of the town, but a recent assessment shows that the A259 is at risk from wave overtopping of the seawall close to the junction with the A21. A storm in 1999 (estimated to be about a 1:10 return period event) caused flooding of part of the area and wave damage to seafront buildings. There is also significant risk of coastal erosion (potentially affecting nearly 400 properties and considerable infrastructure). It is expected that continued climate change, reflected in increased sea levels and resulting larger waves at the sea wall will exacerbate the existing problems (Figure 5.6). Figure 5.6 Volume of water overtopping defences at Hastings 180 Overtopping Rate (litres per metre of defence per second) m sea level rise m sea level rise 0.2m sea level rise 40 Now 20 0 Annually 1 in 10 1 in in 1000 Frequency The area has been identified for urgent works designed to protect against overtopping in a 1:50 year storm and a breach of the seawall in a 1:200 year storm. Hastings is an important regional centre on the south coast, dominated by a combination of tourism-related developments (e.g. hotels and attractions) and residential properties. The town supports 86,000 people in 38,000 households and this is predicted to rise to 91,000 people by The beach and seafront activities are important to the economy of the town. Tourism is the major contributor providing some 3,000 jobs, while the commercial and recreational activities that line the A259 are also important sources of employment. Increased flood risk would badly affect tourism and consequently have wider community impacts. Hastings and neighbouring Bexhill have been recognised as priority areas for regeneration and a 10-year investment programme was announced in May 2002, with initial funding of 38 million. The aims of the regeneration programme are to provide space for commercial and educational activities, new jobs and businesses, improved educational attainment and new homes. This could be jeopardised if the risk of flooding and coastal erosion are not appropriately managed. It is vital that the risk of all sources of flooding and coastal erosion are adequately understood and that the regeneration and development of the town is planned with this in mind to ensure sustainability in the face of inevitable sea level rise.

39 COASTAL FLOODING: FUTURE RISKS AND INVESTMENT REQUIREMENTS 37 Figure 5.5 Hastings flood extent and key sites at risk