Coastal Erosion Risk Research Articles

Master Plan of solutions to mitigate the risk of coastal erosion in Calabria (Italy), a case study

This paper describes the scientific aspects analysed in the preparatory phase of a Master Plan of interventions to mitigate the risk of coastal erosion in Calabria. The Plan has recently been developed by the regional administration to define in an objective manner a scale of priorities for the planning and intervention of the medium and long-term re-equilibrium of the coastline. The analyses developed in this paper allow us to correctly evaluate, from several points of view, the consequences of possible proposed solutions, and thence to make choices based on accurate documentation and reliable analysis of the physical, environmental, social and economic aspects, all of which are closely interrelated.Such a Master Plan is necessary in Calabria both because of the geographic shape of the land, characterized by a coastline over 700 km long and which is fundamentally important to the regional economy, and also because of the presence of a significant number of past ad hoc interventions in coastal defence, often carried out by different institutional bodies, as a matter of urgency, and in areas of limited access, generally without sound or effective design or general vision of the problem, the result of which has only served to shift, in spatial and temporary terms, the problem of coastal erosion.

Hazard, vulnerability and coastal erosion risk assessment in Necochea Municipality, Buenos Aires Province, Argentina

This contribution determines the coastal erosion risk of Necochea and Quequen cities, Necochea Municipality, Buenos Aires Province (Argentina). Both risk components, hazard and vulnerability, were assessed by the construction of indices. The hazard index is composed of four indicators: the erosion or accretion rate, coastal geomorphology, storm waves effects, and sediment supply. The vulnerability index is comprised of land use/cover, demographic, life conditions, and work and consumption indicators, and includes population census data such as demographic, education, health, sanitary, economic, production, work and population exposure aspects. The analysis concluded that coastal erosion risk ranges from very low to high along the study area, Quequen yielding the highest values. Risk levels vary in both cities based on the uneven spatial distribution of hazard. The risk assessment developed herein constitutes a practical and adequate tool that can be utilized with other elements and tasks in the elaboration of a coastal management program.

Coastal Restoration as Contested Terrain: Climate Change and the Political Economy of Risk Reduction in Louisiana

Although many studies have examined the effects of structural factors and institutional interests on risk estimation practices, little is known about the political dynamics surrounding divergent responses to risk reduction measures. This article examines the political economy of risk reduction, using a case study of Louisiana's coastal restoration planning and decision‐making process. Specifically, the article draws on documentary evidence, long‐term ethnographic field observations, and semistructured interviews to investigate the proliferation of risk conflicts and disputes surrounding the 2012 Louisiana Comprehensive Master Plan for a Sustainable Coast, the latest long‐term risk‐reduction plan to slow coastal erosion and achieve a sustainable coast. As I point out, coastal restoration in Louisiana is contested terrain where a variety of contentious groups struggle to influence and control debates over climate change risk and coastal erosion risk reduction. By examining the proliferation of contested risk definitions and risk reduction strategies in Louisiana, I aim to provide new insight into the organizational and institutional forces that shape positions on risk, the political‐economic forces that create and allocate risk, and the social construction of community identity and culture through risk debates.

Techniques for valuing adaptive capacity in flood risk management

Flood and coastal erosion risk management has always faced the challenge of decision making in the face of multiple uncertainties relating to the climate, the economy and society. Traditionally, this has been addressed by adopting a precautionary approach that seeks to protect against a reasonable worst case. However, a managed adaptive approach can offer advantages. The benefits include improved resilience to negative changes, enabling opportunities from positive changes and greater cost effectiveness. The absence of clear methods and tools to value adaptive approaches has been recognised as an obstacle to wider adoption. This paper proposes a staged approach to building in adaptive capacity, which systematically analyses uncertainties, identifies opportunities to incorporate adaptability and appraises benefits through the analysis of decision trees. A case study is presented. The methodology is set in the context of appraisal processes used in England by the Environment Agency, based on cost–benefit analysis guidance issued by HM Treasury. The approach is transferable to other situations worldwide, where decision making is based on quantified assessment of costs and benefits. The work should help decision makers fully appraise the benefits of building in adaptive capacity and make the economic and technical case for adaptive flood risk management in an uncertain environment.

Vulnerability assessment for preliminary flood risk mapping and management in coastal areas

Planning and management of coastal environment, both terrestrial and marine, is affected by several actions in environment resource conservation and improvement, paying specific attention to risk forecasting and preventing. In such context, the EU flood Directive 2007/60/EC, which requires Member States the assessment and management of flood risk, and the EU water framework Directive (2000/60/EC) are the key factors in the integrated river basin management to assure an efficient and rational use of resources. Afterwards, coastal risk assessment and mapping are a propaedeutic phase to plan and manage coastal areas. In this work, risk analysis refers to the results obtained by the combined application of coastal flooding and erosion risks in the activities carried out to prepare the Regional Coast Management Plan for the Ionian coast of Basilicata Region located in the south of Italy. In order to define the driving forces acting on the shore, high-resolution lidar data, bathymetric information and wave climate statistics referred to different acquisition times are used. The systemic vulnerability estimation is achieved by composing both hazard factors combined in the Coastal Criticality Index depending on the assessment of Coastal Flood Index and Coastal Erosion Index based on morphologic and socio-economic variables.

Nature-based solutions: lessons from around the world

This paper considers an emerging group of coastal management approaches that offer the potential to reduce coastal flood and erosion risks while also providing nature conservation, aesthetic and amenity benefits. These solutions mimic the characteristics of natural features, but are enhanced or created by man to provide specific services such as wave energy dissipation and erosion reduction. Such approaches can include beaches, dunes, saltmarshes, mangroves, sea grasses, coral and oyster reefs. The paper describes a number of innovative projects and the lessons learned in their development and implementation. These lessons include the planning, design and construction of projects, their development following implementation, the engagement of local communities and the cost-effectiveness of solutions.

Alternative business models for flood risk management infrastructure

Over the next 100 years, it is estimated that England will need £30.6-1bn annual investment to manage flood and coastal erosion risk. Given constraints on central government spending following the 2008 financial crisis, the full burden of this is unlikely to be met by government alone. There is therefore a need to consider the potential for alternative business models for flood risk management infrastructure. An infrastructure business model describes how value is created, delivered and captured over the life cycle of the infrastructure system – this includes but is not limited to funding and financing. Alternative business models are starting to emerge across a range of infrastructure sectors, predominantly motivated by two key factors: (i) mainstream approaches do not deliver the benefits that communities want, (ii) tax payer funds are too constrained to deliver all the infrastructure investment that is sought. This paper presents and discusses a number of alternative business models for flood risk management infrastructure. Those currently under consideration focus on funding and financing, important though these issues are, it is only by capturing social, environmental and other values of infrastructure will flood risk stakeholders be able to identify approaches that are best suited to deliver their objectives and for alternative business models to emerge in practise.

Long term investment scenarios and an opportunity to collaborate

In December 2014 the Environment Agency published Long Term Investment Scenarios (LTIS) for flood and coastal erosion risk management in England. It sets out the future costs and benefits of managing flood and coastal erosion risk in England in a range of different scenarios. Its major achievement in long-term risk-based resource allocation is to incorporate a rigorous national economic optimisation based on an aggregation of 3,000 flood defence systems covering the entirety of England’s floodplain. The analysis is based on the Environment Agency’s national assessment of flood risk from rivers and the sea, along with the risk of properties flooding from surface water. The risk information informs an innovative economic model to assess optimal levels of investment both in maintaining and improving the defence infrastructure, and is combined with a high level appraisal of investment in broader risk management activities (such as flood incident management). The headline results describe optimal investment profiles in the short and long term, and compare these with planned investment levels by government and external contributors. The potential to reduce flood risk in the long term is described in the context of the efficiencies required to reduce and hold down costs, the benefits of maintaining control over development in the floodplain, and the effects of climate change. There are constraints in the economic optimisation approach, as well as in the broader, inclusive overview of risk management activities, and the Environment Agency is now seeking a more open, collaborative approach – working with industry and academic partners – to develop LTIS and strengthen it further as robust, independent, world-leading evidence.

Asset Management Planning – providing the evidence to support robust and risk-based investment decisions

Over the last decade the UK’s joint Flood and Coastal Erosion Risk Management Research and Development programme has been developing methods to support a move to a risk-based approach to flood defence asset management. Looking to ensure investment is less ‘find and fix ’ and made to those assets where the biggest risk reduction can be made for the money available. In addition, providing the capability to articulate the benefits of investing in these assets quantitatively and transparently. This paper describes how the Asset Performance Tools (APT) project [1] is delivering practical methods, prototype tools and supporting guidance which, together with related initiatives such as the Environment Agency’s Creating Asset Management Capacity (CAMC) strategic programme [2] and the ‘State of the Nation ’ (SoN) [3] supportive datasets, will enable a risk-based, ‘predict and protect ’ approach to asset management. A key advance is the ability to bring in local knowledge to make national generic datasets locally relevant. The paper also highlights existing outputs that can already be used to support a more proactive approach to asset management. It will summarise the ongoing work which will further develop and fine tune performance assessment and investment decision processes within an integrated conceptual framework aligned with ISO55000, deliverable via CAMC and whose concepts can be used by all risk management authorities.

Residents' Perceptions toward Coastal and Dune Management: An Evaluation of the Hightown Dune Restoration Project (HDRP), UK

Residents' perceptions are intangible ideas that may impact tangibly on coastal and dune management strategy and contribute truly for the sustainability of coast and dune restoration project. This study utilizes a qualitative approach to investigate residents' perceptions of the effectiveness of the measures implemented by Sefton Council to protect the Hightown dunes and coast from the risks of coastal erosion and flooding, and preserve local biodiversity. Findings revealed that residents regarded the measures as ineffective and considered the area safe so long as climatic conditions remained consistent. The study highlights the necessity of local community involvement in comprehensive coast and dune management plans to ensure project sustainability.

A short guide to doing nothing at the seaside

This paper focuses upon the new landscape of strategic coastal planning and implementation in England and Wales resulting from the development of shoreline management plans (SMPs) by flood and coastal erosion risk management (FCRM) authorities; the issues raised will be very familiar elsewhere in the world. The real test is how to implement the many measures and management decisions within these SMPs. In many cases, those decisions were difficult to reach; sometimes the result was an uneasy agreement to maintain defences indefinitely, if the funding is available; elsewhere, bold decisions were taken to withdraw maintenance using the ‘no active intervention’ SMP policy option. This policy is often paraphrased as ‘do nothing’, but in reality it is usually far from being a passive exercise. Depending on the circumstances and rationale for not intervening, it may entail a lot of work and have many implications. What is the nature of current intervention? Are there existing FCRM assets in place, and if so, will they be dismantled or left to disintegrate? Either way, potential impacts upon public health and safety, the natural environment, coastal processes, amenity and local communities and businesses need attention, and the exercise needs careful planning and engagement. There may be other options to consider, such as the ‘localisation’ or transfer of assets, and management of them, to third parties – but what are the liabilities associated with this and is it sustainable? A well-planned decommissioning of assets that is written into a SMP in advance is more likely to address these implications successfully, whereas a withdrawal from maintenance in the teeth of local opposition despite an original intention to defend may become complicated. The FCRM community needs to be prepared for these decisions and their consequences in advance. Additionally, is ‘no active intervention’ compliant with European law? The Environment Agency and the Department for Environment, Food and Rural Affairs are working with local authorities and other partners on a number of initiatives that will clarify issues, review experience and provide simple, practical guidance to risk management authorities faced with implementing a ‘no active intervention’ option. This paper will highlight the results and products of some of these initiatives and reflect more widely on the ‘deliverability’ of SMPs as they stand. ‘Doing nothing’ at the coast is clearly less relaxing than it sounds.

Climate impacts on flood and coastal erosion infrastructure

Climate change can affect the performance of flood and coastal erosion risk management infrastructure (FCERMi) through a number of mechanisms. This review highlights that while it is well known that climate change can influence the performance of FCERMi in a number of ways, there is extremely poor quantitative understanding of the physical processes of time-dependent deterioration and the impact of changing loads (and the interactions between these) on the reliability of FCERMi. If FCERMi is to be more robust to future climate uncertainties, there is an urgent need for research to better understand these interactions in the long term. This must be coupled with an updated approach to design and management that considers changes in extreme values, storm sequencing, spatial coherence, or more subtle impacts from changes in temperature, solar radiation and combinatorial affects.

Coastal Dynamics of the Curonian Spit within the Russian Part of the Southeastern Baltic

The coastal dynamics of the Curonian Spit, a large accretive landform with its eroded root, is discussed. For this area, the new data on the coastal development for the last 100 years were obtained; the characteristic of current coastal state was given; mathematical simulation of the coastal processes for assessment of the sediment deficit in the near shore zone was made. Evanescence of the sediment deficit phenomenon in the area under study is demonstrated. Here, even during rather short periods of the deficit increase, the development of wave-induced destructive processes is observed; therefore three major ways to mitigate the risk of coastal erosion (i.e. the construction of impenetrable or penetrable groins, a detached breakwater and an artificial beach) are considered, including the peculiarities of the spit shores development as a result of coastal protection activities.

Methods for coastal monitoring and erosion risk assessment: two Portuguese case studies

This research was partially supported by the European Regional Development Fund (ERDF) through the COMPETE – Operational Competitiveness Programme and national funds through FCT – Foundation for Science and Technology, under the project “Pest-C/ MAR/LA0015/2013”, and partially funded by the Project ECORISK (reference NORTE-07-0124-FEDER- 000054), co-financed by the North Portugal Regional Operational Programme (ON.2 – O Novo Norte), under the National Strategic Reference Framework (NSRF), through the European Regional Development Fund (ERDF). Wave climate analyses were supported by the FCT-funded RAP project (PTDC/MAR/111223/2009).

GIS-based methodology for erosion risk assessment of the muddy coast in the Yangtze Delta

Muddy coasts are widely distributed around the world, especially adjacent to large estuaries. These regions are highly susceptible to coastal erosion with its dense population, developed economy and low-lying land. Due to immense natural and human pressures, there is an urgent need for a more comprehensive understanding of coastal erosion risk in such areas. Various models have been established, but most of them focused on sandy coasts and physical factors that influence coastal erosion while socioeconomic factors were usually ignored. Accordingly, this study presents a GIS-based risk assessment of coastal erosion for muddy coasts by combining both the physical and socioeconomic aspects of erosion. The method is used to assess coastal erosion risk in the Yangtze Delta. Based on the DPSIR (Driving forces, Pressure, State, Impact, and Response) framework, 10 vulnerability indicators and 3 impact indicators corresponding to physical and socioeconomic aspects, respectively, are identified to constitute an indicator system. These indicators are weighted using the Analytic Hierarchy Process (AHP) technique, and then are combined into a Vulnerability Index and a Hazard Index, which then are merged into a Risk Index. Then, these indexes are normalized to 0%–100%. Finally, the normalized values are ranked into 5 levels: very low (<20%), low (20% ≤ Is<40%), moderate (40% ≤ Is<60%), high (60% ≤ Is<80%) or very high (≥80%). This study is the first to comprehensively assess coastal erosion risk in the Yangtze Delta by integrating physical and socioeconomic factors at a detailed spatial scale. The results provide a clear picture of the current coastal erosion risk in the study area, despite of some limitations. The study also reveals key gaps in data gathering and coastal management practices that need to be addressed in order to develop more effective long-term coastal management.

Risk assessment of coastal erosion of Karasu coast in Black Sea

Coastal erosion occurs as a result of human ac tivity and natural phenomena. Coastal erosion causes significant economic and ecological problem. There is continuing serious coastal erosion along the Karasu coastline. This study reports on the process of determining the extent of the coastal erosion using satellite images from different time periods and the analysis of the risk to the environment. The change in the coastline over a 26-year period from 1987 to 2013 was determined using satellite images. In this study, significant coastline movements were detected for a 26-year period. For this study, the Karasu coastline was subdivided into 7 sections for analyses the coastal erosion risk. The risk of each section can be determined by using the classic risk. The results showed that both sides of the river outfall and the coastline have a moderate risk level with the area of the breakwater has a low risk.

Guide to drawdown capacity for reservoir safety and emergency planning

A key factor in avoiding and minimising the impact of catastrophic dam failure is the ability to draw a reservoir down in the event of an emergency. In the UK there is currently no single accepted approach to determining what represents an acceptable rate of reservoir drawdown. A project is therefore currently being carried out, under the joint Environment Agency/Defra (Department for Environment, Food and Rural Affairs) Flood &amp; Coastal Erosion Risk Management (FCERM) research and development programme, to research and produce guidance on the drawdown capacity required for reservoir safety. This paper summarises some of the research findings from stage 1 of this project and sets out the proposed approach to develop the guidance in the next stage of the project.

Public perception of engineering-based coastal flooding and erosion risk mitigation options: Lessons from three European coastal settings

Recent damages and losses associated with coastal floods have generated many analyses dealing with overexposure to flood risk, its consequences, associated technological choices and governance principles, and what seems to be a poor understanding of the causes and consequences of floods and working of coastal defences at the local level. While many analyses demonstrate that risks are both physically and socially constructed, in this paper we go further by analysing risk mitigation options (engineering works) as being dual (physically and socially constructed) as well.When envisioning mitigation options through stakeholders' perception, one can observe a mix of intertwined statements associated with the relevance the specific risk that is dealt with, dealing with the sometimes incomplete knowledge associated with the mitigation option and its performance at reducing risk, and, dealing with the value conflicts that may be present when envisioning a particular flood risk mitigation strategy. Our research question is “what are the drivers of stakeholder perceptions when envisioning engineering-based mitigation options.”Through qualitative empirical fieldwork conducted in three European coastal settings (Cesenatico, Santander and the Gironde Estuary) we demonstrate here that engineered mitigation solutions are socially construed by referring to individual and collective heuristics associated with these options. These heuristics may lead to poor social acceptability of envisioned mitigation options, poor acceptability not directly linked to the performance in terms of risk reduction.

An approach to assess flooding and erosion risk for open beaches in a changing climate

This paper examines the vulnerability to flooding and erosion of four open beach study sites in Europe. A framework for the quantitative estimation of present and future coastal flood and erosion risks is established using methods, data and tools from across a range of disciplines, including topographic and bathymetric data, climate data from observation, hindcast and model projections, statistical modelling of current and future climates and integrated risk analysis tools. Uncertainties in the estimation of future coastal system dynamics are considered, as are the consequences for the inland systems. Different implementations of the framework are applied to the study sites which have different wave, tidal and surge climate conditions. These sites are: Santander, Spain—the Atlantic Ocean; Bellocchio, Italy—the Adriatic Sea; Varna, Bulgaria—the Black Sea; and the Teign Estuary, UK—the northern Atlantic Ocean. The complexity of each system is first simplified by sub-division into coastal “impact units” defined by homogeneity in the local key forcing parameters: wave, wind, tide, river discharge, run-off, etc. This reduces the simulation to that of a number of simpler linear problems which are treated by applying the first two components of the Source–Pathway–Receptor–Consequence (S–P–R–C) approach. The case studies reveal the flexibility of this approach, which is found useful for the rapid assessment of the risks of flooding and erosion for a range of scenarios and the likely effectiveness of flood defences.

Modelling of Coastal Infrastructure and Delta River Interaction on Ionic Lucanian Littoral

Coastal risk and related prevention and prediction activities are key topics in coastal environment planning and management connected to coastal erosion risk assessment, flood risk and coastal inundation. Further, moving up to general environmental impact, even related to risk assessment, the realization of human activities or infrastructures along the coast generally introduce drastic changes in longshore sediment rating and wave climate effects during both wave motion and storm surge. In such case, numerical models can be effective tools in local coastal planning, scheduling and management activities in both ordinary and emergency conditions. In fact, advanced and complex computational model availability allows numerical and graphical description of such scenarios aimed to define possible mitigation and contrast measures and or interventions by simulating alternative configurations/scenarios. In the paper the results of a medium-term morphological modeling of the interaction between marina and delta river, in ionic-Lucanian littoral in Basilicata region, are showed and discussed comparing the numerical outputs to observed changes of the local morphology gained by Lidar detection