National Network of Regional Coastal Monitoring Programmes
CoastalRes: Coastal Resilience in the face of Sea Level Rise
Background
Credit: Jon French, University College London
Climate change and sea-level rise pose a significant threat to most coasts, including the likelihood of increased coastal erosion and flooding. In the UK, these hazards have been managed from a risk-based perspective over the last few decades, requiring an evaluation of the costs and benefits of different management approaches. This is exemplified in government project appraisal guidance and studies such as the Foresight Future Flood and Erosion Study published in 2004 and subsequent national assessments.
In the last 10 years, a resilience-based perspective towards coastal flooding and erosion has become increasingly prominent in national policy documents. Resilience is a broader concept that incorporates risk, but goes beyond it to consider the ability to anticipate and recover from adverse events that will inevitably occur. Despite its attraction, the concept of resilience remains ill-defined in many policy documents and largely qualitative. This greatly limits the potential the development and application of an overarching resilience-based framework to guide and shape coastal erosion and flood hazard management.
This 12-month project funded by the SPF UK Climate Resilience Programme set out to develop and demonstrate prototype methods to assess realistic pathways for strategic coastal erosion and flood resilience in the light of climate change, and to consider how resilience might be operationalized as a robust evidence-based framework for achieving more sustainable, equitable and societally acceptable adaptive responses to climate change at the coast. The main challenge was to devise a robust framework for quantifying resilience, such that comparative geographical assessments and forward modelling of temporal changes and the effects of specific adaptation pathways become possible.
The CoastalRes methodology was developed using local case studies and the entire coast of England as a case study, and demonstrates the practicality of formalising and quantifying resilience at multiple scales. This includes a pragmatic definition of resilience that encompasses not only the physical and ecological but also the socio-economic dimensions of coastal systems. Scenarios are used to model the impact of external drivers (e.g. climate change, land use, etc.) exploring likely response to selected policy options. Capitalising on the increasingly availability of open-source geospatial datasets, multi-variate measures are mapped over the flood and erosion hazard zone and combined using Multi Criteria Analysis (MCA) model to create spatially and temporally variable resilience indices. Subjective weightings within MCA are used constructively to provide an explicit and transparent representation of diverse stakeholder views.
Key aspects of the project include:
- Identifying an appropriate definition of resilience.
- A series of stakeholder workshops, which examined the current status of shoreline management planning, and the status of resilience in these policy processes. This contributed to and helped to assess the utility of the CRM.
- Assessment of national datasets suitable for examining coastal risk and resilience.
- Development of a tool (the Coastal Resilience Model (CRM)) to quantitatively measure resilience to coastal erosion and flood hazard.
A pragmatic definition of resilience
The realisation of resilience to coastal erosion and flooding for the English case study. These objectives are maximised or minimised to enhance coastal resilience, and are quantified using indicators and associated data-driven metrics.
Like sustainability, resilience is an elusive concept and its practical application has been hampered by inconsistencies in definition. Here a pragmatic definition adopted by the US Army Corps of Engineers (USACE) that emphasises “the ability of a system to prepare, resist, recover, and adapt to disturbances in order to achieve successful functioning through time” is used as a basis. The USACE have adapted this to their circumstances and have focused on coastal disaster risk management and recovery, especially the response to hurricanes. In the Coastal Resilience Model, we have adapted this definition to an English context as illustrated in the image.
Relevant papers on coastal resilience
Linkov et al (2014) Changing the resilience paradigm, Nature Climate Change 4, 407–409 https://doi.org/10.1038/nclimate2227
Rosati et al (2015) Quantifying coastal system resilience for the US Army Corps of Engineers, Environment Systems and Decisions 35, 196–208 https://doi.org/10.1007/s10669-015-9548-3
National datasets for examining coastal risk and resilience
Example of variables used to represent the components of coastal risk: hazard is represented by (a) likelihood of flooding and (b) shoreline change; exposure is defined by (c) population and (d) buildings; and vulnerability is described by (e) coastal defences and (f) social disadvantage.
Credit: Figure and data synthesis by Sofia Aldabet (University of Southampton)
As a precursor to a more detailed analysis of coastal system resilience, a snapshot of coastal flood and erosion risk at the national scale was produced, using publicly accessible datasets covering the entire coastline of England.
The datasets used were categorised to indicate which aspect of risk (hazard, exposure or vulnerability) they represent:
- hazard
- likelihood of flooding, from the EA "Risk of Flooding by Rivers and Sea" dataset (EA 2019)
- Landsat-derived measurement of long-term shoreline change between 1984–2016, from the Deltares AquaMonitor (Luijendijk et al., 2018)
- exposure (within the delineated coastal floodplain)
- population, using "OpenPopGrid" – a gridded population dataset that spatially redistributes 2011 UK census data over a grid based on Ordnance Survey residential building footprints (Murdock, 2015)
- building footprints, from the EDINA Digimap OS Open Map Local data layer (Ordnance Survey Service, 2019)
- vulnerability (within the delineated coastal floodplain)
- coastal defences, using the UK National Defences dataset held by the Channel Coastal Observatory (CCO, 2014)
- social disadvantage, using the national "River and Coastal Flood Disadvantage Index" (Lindley et al., 2011) – which accounts, at least in part, for social factors that influence vulnerability, using indicators that refer to the adaptive capacity, enhanced exposure, and personal sensitivity of the population at risk of flooding (England and Knox, 2014).
This exercise demonstrated that there remains much that England (and by implication the whole UK) can improve regarding the open-accessibility and spatial/temporal coverage of its national coastal datasets. A particular and urgent need is for a comprehensive inventory of coastal defences, including infrastructural histories (year of installation, years of maintenance) and specifications.
Taking this onboard, the prototype Coastal Resilience Model was constructed with the available open access datasets as explained in Carpenter and Hill (2020). The approach is designed to be flexible and adaptable, including allowing for improved datasets.
Coastal Resilience Model
Geographical variation in coastal Resilience Index (composite of economic, social and environmental perspectives) around the English coast with the distribution of RI values. Hexagons are 90 km2 output areas.
The prototype Coastal Resilience Model (CRM) quantifies the economic, environmental and social dimensions of resilience with reference to a suite of performance measures that can be assessed using open-access geospatial datasets. The analytical approach uses Multiple-Criteria Analysis (MCA) to derive a composite Resilience Index derived from a broad set of diverse measures and data, as well as stakeholder weightings.
MCA has sometimes been criticised for its inherent subjectivity in the identification of the measures, and their normalisation (scoring) and relative weighting. In this context, this subjectivity can be used constructively to provide an explicit and transparent representation of different stakeholder perspectives and priorities, which are an essential component of evaluating resilience.
The CRM expands current risk-based shoreline management planning to take account of some of the complexity of community characteristics and local priorities, while recognising that these occur within a much broader coastal system. In addition to mapping the current state of coastal resilience, the CRM can also represent past and future resilience. Given suitable hazard and socio-economic scenarios, modelled resilience time trajectories can be created using CRM to reveal the impact of alternative coastal development and adaptive pathways.
Resilience is shown to have high local variability although, at a national scale, clear geographic patterns emerge. The geographic patterns in the Resilience Index computed for simulated economic, social and environmental stakeholder perspectives also differ markedly.
An online public version of the CRM has been developed and is available at: https://coastalresilience.uk/crm/. This version is designed to encourage users to think about coastal resilience and how they could apply the concept to real world problems. There are many value judgements which need to be made and the portal provides the opportunity for users to explore the potential implications of such judgements. We think further development is needed to establish an operational coastal resilience tool, especially with respect to data coverage and scenario modelling, and the portal provides a demonstrator to help advance the idea and its practical application.
Stakeholder workshops
Credit: Ian Townend, University of Southampton
This research has taken a strongly participatory approach to understand the current status of coastal erosion and flood management and how it might evolve in the future. The major policy instrument for England is the current Shoreline Management Planning (SMP) framework, including the SMP2 Refresh. Accordingly, we examined the SMPs and the extent to which these are appropriate as a framework that can deliver the enhancement of coastal resilience that is advocated by recent policy statements and climate change adaptation guidance.
During 2019 a series of workshops were held in London, Havant and York to discuss shoreline management planning today, and the challenges faced in a changing climate. These workshops were attended by coastal managers, engineers, coastal process scientists, heritage experts, environmentalists, planners, academics, councillors, government representatives and supported by consultations spanning 45 organisations, representing all of England and Wales at both national and regional levels.
The workshops considered the current status of coastal risk management and shoreline management planning, and how change is anticipated to develop strategic proactive management plans. Discussions covered the physical and the socio-economic aspects of the coastal system and how these are likely to evolve in response to climate change. The following messages were apparent:
- Coasts need a new and possibly radical vision for the future or new methodologies to achieve current aims as more of the same is unrealistic. Where radical change is needed this will help coastal communities prepare for and cope with this change
- Many of the policy transitions envisaged above and in existing SMPs (e.g., moving from 'hold the line' to 'managed realignment') are more profound than just coastal engineering and also transform the associated coastal community and landscape.
- The future vision needs implementation, and evolving management processes should be able to deliver on this. There are opportunities to be found in: ensuring adequate funding streams to areas experiencing change, co-developing action plans based on trigger points, and education and engagement to reconnecting people and nature to improve understanding of coastal change.
- Together these should take a step towards creating a more resilient coast with a reduced potential for coastal blight over short (<10 years) and medium (up to 50 years) timescales.
Acknowledgements
Credit: Robert Nicholls, Tyndall Centre for Climate Change Research
This work was undertaken by the University of Southampton, University College London, Middlesex University, University of East Anglia, Bournemouth University and the Channel Coastal Observatory, supported by the SPF UK Climate Resilience Programme through UK Research & Innovation award NE/S016651/1. Project partners included ABPmer, the Coastal Group Network, National trust, RSPB, Wildfowl and Wetlands Trust, National Flood Forum, Natural England and Network Rail. The East Solent Coastal Partnership and the Scarborough District Council hosted our regional workshops.
Further resources:
| UK Climate Resilience Programme webinar (28/10/2020) |
| CoastalRes Methodology Report Townend et al (2020) |
| CoastalRes Technical Report Carpenter and Hill (2020) |
| Policy brief - Improving the resilience of our coastal communities |
| Final Workshop presentation |
| Workshop summary |
| Townend, B. I. H., et al2021. Operationalising coastal resilience to flood and erosion hazard: A demonstration for England. Science of The Total Environment, 783, 146880. https://doi.org/10.1016/j.scitotenv.2021.146880 |
| Townend et al (2020) 'The CoastalRes prototype resilience model' |
| Brown, S. et al. 2023. Transitions in modes of coastal adaptation: addressing blight, engagement and sustainability, Frontiers in Marine Science, 10. https://www.frontiersin.org/articles/10.3389/fmars.2023.1153134 |
| weADAPT: Improving the resilience of UK coastal communities |
| Lazarus, E. D. et al 2021. The UK needs an open data portal dedicated to coastal flood and erosion hazard risk and resilience, Anthropocene Coasts 4 (1), 137-146, https://doi.org/10.1139/anc-2020-0023 |
| NEW Poster - Coastal Resilience Nicholls R J, French J R, Penning-Rowsell E C, Carpenter S, Lazarus E, Aldabet S, Tompkins E L, Thompson C E L, Brown S, Haigh I D, Townend I H, Hill C T, Waldock I, Sadler J |
| Online public version of CRM (2022) |
