Coastal Erosion Risk Research Articles

Research, policy and practice for the conservation and sustainable use of intertidal mudflats and saltmarshes in the Solent from 1800 to 2016

Improvements in both knowledge and actions are required to realize the conservation and sustainable use of intertidal mudflats and saltmarshes in the UK, specifically in terms of decision-making. The research presented in this paper constructed a timeline of events pertaining to the conservation and sustainable use of intertidal mudflats and saltmarshes in the Solent from the perspective of those involved, in order to establish what is actually happening, why, how, and by who. The evidence demonstrates an abundance of research and consultation for legislation and policy development purposes, with a relative lack of practice to actively conserve and sustainably use intertidal mudflats and saltmarshes. The majority of the events identified in this study indirectly influenced the conservation and sustainable use of intertidal mudflats and saltmarshes, and were primarily concerned with some other purpose, such as coastal flooding and erosion risk management, and dock development. Research, legislation and policy, and practice are interconnected in a complex web, with changes in one domain being reflected in another. Yet despite the significant investment in research and consultation processes by many people over numerous years, no clear end point appears to have been reached in terms of realizing intertidal mudflat and saltmarsh conservation and sustainable use. Based on the findings of this study, it is imperative that further in-depth studies be undertaken in order to identify and evaluate changes to improve the decision-making process through which more informed, timely decisions and more effective, concerted actions to conserve and sustainably use intertidal mudflats and saltmarshes can be taken. The concepts and methods applied in this study are transferable to other complex decision-making situations in the UK and elsewhere.

An integrated risk assessment of coastal erosion based on fuzzy set theory along Fujian coast, southeast China

Coastal erosion and accumulation has always existed and contributed to the shaping of the present coastlines. However, coastal erosion now is largely intensified due to human activities, causing severe land loss and aggravated financial burden, which is not acceptable. This paper presents an integrated methodology for risk assessment of coastal erosion, aiming at assessing and mapping coastal erosion risk by integrating hazard, exposure and coping capacity to give risk priority and risk mappings to guide coastal erosion risk management. Delphi method, the analytic hierarchy process and the fuzzy set theory were adopted in the study to establish the methodology. Fujian province situated at southeast China was taken as a case study; the final result was effectively supported by the data and provided lots of important information for coastal management. The final risk priority recorded the risk disparities from place to place and ranked them with distinct levels to emphasize those places of higher risk levels which needed urgent mitigation measures for risk reduction, and risk mapping gave a visual and clear impression of risk distribution. The risk priority and mapping was only the first step to coastal erosion management; identification of priority areas, implementation of mitigation measures and regular maintenance and monitoring are advanced jobs need to be done.

Guidelines for the strategic management of flood risks in industrial plant oil in the Brazilian coast: adaptive measures to the impacts by relative sea level rise

This study provides guidelines for strategic management in industrial oil plants linked to uncertainties of climate change through the development of integrated planning methodology with focus on coastal flooding events caused by relative sea level rise (RSLR). The research site is in Redonda Island, located in Guanabara Bay, Rio de Janeiro City, Brazil, and since 1960, it constitutes an industrial oil plant facility. The region suffers interaction with storms and meteorological tides from extratropical cyclones over the South Atlantic Ocean, being vulnerable to risks of disasters, floods, and coastal erosion. A Program on Vulnerability and Adaptation Assessments to Relative Sea Level Rise (“Programa de Avaliacao e Adaptacao as Vulnerabilidades de Elevacao do Nivel Relativo do Mar—PAAVENRM”) was developed to avoid compromising the regional and local development in the industrial system of the island, which is an ad hoc instrument designed to anticipate and reduce risks, damages, and losses by occurrence of extreme climatic events in coastal areas prone to flooding caused by RSLR. Results from computer simulation modeling indicate 37 prospective qualitative scenarios that consolidate the conditions of future climate vulnerability of the plant, starting from United Nations Intergovernmental Panel on Climate Change (IPCC) information for RSLR up to 2100. Three quantitative forecasting scenarios were simulated, under boundary conditions preset for different altimetric ranges subject to submersion, based upon ordinary and extraordinary tides measured in the area in relation to RSLR, which allowed the evaluation of the industrial infrastructure at risk. Furthermore, three thematic maps were elaborated for the planning of specific coastal protection interventions. Percentages of physical damage and property losses were estimated. The importance of applying guidelines for medium and long-term corporate strategy management, integrating the risk of flooding, the rigging of civil defense systems, meteorology, and of the plans, programs, and existing systems and others to be developed is highlighted. From this perspective, the proposed scenarios help to identify the most relevant alternatives for mitigation and adaptation under technical criteria for decision making in the study area.

Using geospatial business intelligence paradigm to design a multidimensional conceptual model for efficient coastal erosion risk assessment

One of the main challenges in Coastal Erosion Risk Assessment (CERA) is integrating and analysis of conflicting data in various time periods and spatial scales through dissimilar environmental, social, and economic criteria. Currently, Geographical Information Systems (GIS) are widely used in risk assessment despite their drawbacks and limitations as transactional systems for multi-scales, multi-epochs, and multi-themes analysis. Hence, an analytical conceptual framework is proposed in this paper based on geospatial business intelligence paradigm to develop a Spatial Multidimensional Conceptual Model (SMCM) to assess coastal erosion risk. The model is designed based on Spatial On-Line Analytical Processing (SOLAP) platform, on the top of both analytical and transactional paradigms, to allow fast synthesis of cross-tabulated data and easy comparisons over space, scales, epochs, and themes. This objective is achieved through a comprehensive integration of multiple environmental, social, and economic criteria as well as their interactions at various scales. It also takes into account multiple elements at risk such as people, infrastructure, and built environment as different dimensions of analysis. Using this solution allows decision makers to benefit from on-demand, interactive, and comprehensive information in a way that is not possible using GIS alone. The developed model can easily be adapted for any other coastal region through the proposed framework to perform risk assessment. The advantages and drawbacks of the proposed framework are also discussed and new research perspectives are presented.

Development of the European Tidal Database and its Potential Application to Marine Renewables

ABSTRACT Lawless, M.R and Rodger, D.W., 2013. Development of the European Tidal Database and its Potential Application to Marine Renewables Tidal flows, sea levels and currents influence coastal flood and erosion risk, flood defence design, coastal management and renewable energy production. Historically data for these variables have been obtained from tide gauge records. However, this information is limited in both time and space. Consequently, analysis and planning for sites between gauges has traditionally been established through simple interpolation techniques, thereby leading to higher levels of uncertainty than desirable. For a more reliable application to coastal and ocean engineering, a more holistic approach is required. Initially developed as a response to the increasing threat of flooding from the sea, JBA developed a comprehensive suite of high-resolution hindcast tide-surge models for Western Europe, collectively called the European Tidal Database. The models within this suite simulate every...

Regional patterns of changing beach morphology at a decadal scale

Bradbury AP, Cope SN, Wilkinson C and Mason TE, 2013. Regional patterns of changing beach morphology at a decadal scale In: Conley, D.C., Masselink, G., Russell, P.E. and O’Hare, T.J. (eds.), Proceedings 12 th International Coastal Symposium (Plymouth, England), Journal of Coastal Research, Special Issue No. 65, pp. 452-457, ISSN 0749-0208. The Southeast Regional Coastal Monitoring Programme commenced in 2002 and is on-going. In excess of 1000 km of open coast and estuarine shoreline are monitored at high resolution with a number of tools and at a range of spatial and temporal scales. The programme provides input to flood and coastal erosion risk management at a range of scales, from region-wide shoreline management plans, to detailed and localised geomorphological assessments. Detailed baseline surveys are repeated typically once every 5 years and three full surveys exist now for the entire coast. Sampling of the baseline surveys is conducted typically at biannual temporal interval. Annual analysis is conducted summarising coastal changes within coastal sub cells at a scale of typically 10-100 km. All data from the project are currently freely available via the project website (www.channelcoast.org). Examples are used to illustrate the challenges associated with analysis of coastal geomorphological change over decadal and annual temporal scales. Differentiation between natural coastal processes and management practices are explored.

Management and Protection of Coastal Area, the Importance of Coastal Processes during the Planning Phase

Coastal processes should be one of the main issues in coastal zone management; ignoring it could lead to wrong decisions which, in turn, could lead to environmental disaster. This letter shows some examples of coastal structures that are built without taking into account coastal processes, and discusses their impact on the environment, with the hopes that the examples provided can serve as a warning for any future decisions. The analyzed zone is the coast of the Calabria Region in southern Italy. The coast is being studied as part of an agreement between the Mediterranea University of Reggio Calabria and the Calabria Basin Authority, concerning the redaction of the Coastal Erosion Risk Mitigation Plan. All data and results are obtained from a preliminary study of the coastal processes in Calabria. Calabria, with more than 700 km of coasts, is affected by coastal erosion, so the proper management and protection of the coastal zone represents an important issue that cannot be avoided.

On the coastal erosion risk assessment indexes

China is one of the most severely affected countries by coastal erosion. About 70% of the sandy beaches and most of muddy tidal flat in open water regions are erode. Coastal erosion results in the width of beach being narrowed, bathing beach destruction, coast-protection facilities and roads collapse, and wetland deterioration. These destructions bring many losses to the local people. However, previous coastal erosion studies focused on the hazard of erosion and paid less attention to the risk of erosion. Therefore, it’s necessary to study the mechanism of coastal erosion and build the coastal erosion risk assessment system for the effective coastal management. On the basis of the existed researches, this paper builds the coastal erosion risk assessment index system which contains hazard index system and vulnerability index system. The index system is expected to provide a practical theoretical basis for coastal erosion risk assessment.

Multivariate return periods of sea storms for coastal erosion risk assessment

Abstract. The erosion of a beach depends on various storm characteristics. Ideally, the risk associated with a storm would be described by a single multivariate return period that is also representative of the erosion risk, i.e. a 100 yr multivariate storm return period would cause a 100 yr erosion return period. Unfortunately, a specific probability level may be associated with numerous combinations of storm characteristics. These combinations, despite having the same multivariate probability, may cause very different erosion outcomes. This paper explores this ambiguity problem in the context of copula based multivariate return periods and using a case study at Durban on the east coast of South Africa. Simulations were used to correlate multivariate return periods of historical events to return periods of estimated storm induced erosion volumes. In addition, the relationship of the most-likely design event (Salvadori et al., 2011) to coastal erosion was investigated. It was found that the multivariate return periods for wave height and duration had the highest correlation to erosion return periods. The most-likely design event was found to be an inadequate design method in its current form. We explore the inclusion of conditions based on the physical realizability of wave events and the use of multivariate linear regression to relate storm parameters to erosion computed from a process based model. Establishing a link between storm statistics and erosion consequences can resolve the ambiguity between multivariate storm return periods and associated erosion return periods.

A Perspective on Sea Level Rise and Coastal Storm Surge from Southern and Eastern Africa: A Case Study Near Durban, South Africa

Recent coastal storms in southern Africa have highlighted the need for more proactive management of the coastline. Within the southern and eastern African region the availability of coastal information is poor. The greatest gap in information is the likely effects of a combination of severe sea storms and future sea level rise (SLR) on the shoreline. This lack of information creates a barrier to informed decision making. This research outlines a practical localized approach to this problem, which can be applied as a first order assessment within the region. In so doing it provides a cost effective and simple decision support tool for the built environment and disaster professionals in development and disaster assessments. In a South African context the newly promulgated Integrated Coastal Management Act requires that all proposed coastal developments take into consideration future SLR, however such information currently does not exist, despite it being vital for informed planning in the coastal zone. This practical approach has been applied to the coastline of Durban, South Africa as a case study. The outputs are presented in a Geographic Information System (GIS) based freeware viewer tool enabling ease of access to both professionals and laypersons. This demonstrates that a simple approach can provide valuable information about the current and future risk of flooding and coastal erosion under climate change to buildings, infrastructure as well as natural features along the coast.

GEOGRAFIA URBANA QUE FAZEMOS

This paper presents an overview about the state-of-art of studies on oceanic sandy beaches from the State of São Paulo, within the Coastal Geomorphology point of view. These studies embrace a sort of thematic issues, in special: beach profile monitoring, textural (grain size) parameters, heavy minerals assemblage and related indices, beach sedimentary dynamics, beach sedimentary budget, sediment transport patterns (morpho-textural and wave modeling methods), long term shoreline changes (remote sensing analyses), morphodynamic classification, coastal erosion and associated risk, and environmental sensitivity for oil spill. Some results related to morphodynamic classification, grain size parameters behavior, longshore drift patterns, and coastal erosion (indicators, causes and risk assessment) are showed for the seven morphodynamic sectors that this coast is comprised.

PRAIAS ARENOSAS OCEÂNICAS DO ESTADO DE SÃO PAULO (BRASIL): SÍNTESE DOS CONHECIMENTOS SOBRE MORFODINÂMICA, SEDIMENTOLOGIA, TRANSPORTE COSTEIRO E EROSÃO COSTEIRA

This paper presents an overview about the state-of-art of studies on oceanic sandy beaches from the State of São Paulo, within the Coastal Geomorphology point of view. These studies embrace a sort of thematic issues, in special: beach profile monitoring, textural (grain size) parameters, heavy minerals assemblage and related indices, beach sedimentary dynamics, beach sedimentary budget, sediment transport patterns (morpho-textural and wave modeling methods), long term shoreline changes (remote sensing analyses), morphodynamic classification, coastal erosion and associated risk, and environmental sensitivity for oil spill. Some results related to morphodynamic classification, grain size parameters behavior, longshore drift patterns, and coastal erosion (indicators, causes and risk assessment) are showed for the seven morphodynamic sectors that this coast is comprised.

Real Options in flood risk management decision making

AbstractEffective flood risk management involves the quantification of flood risk and the implementation of cost‐effective, sustainable, and environmentally and socially acceptable measures that reduce flood risk. However, making decisions on the most appropriate long‐term intervention investments can be challenging; this is primarily because of the uncertainties associated with future climate change and socioeconomic development. Real Options analysis is a widely recognised approach for encouraging appropriate climate change adaptation and mitigation investment decisions. To date, however, there has only been limited use of Real Options Analysis Techniques within the Flood and Coastal Erosion Risk Management community. In this paper, a methodology is described that has the capability to assess the most appropriate set of interventions to make in a flood system, given the future uncertainties. The methodology captures the concepts of Real Options and has the capability to value the flexibility associated with potential flood risk management intervention options across a range of future climate change and socioeconomic scenarios. The novel Real Options approach has been tested and verified on a real‐life case study situated in the Thamesmead area of the Thames Estuary. The results obtained demonstrate the potential for substantial cost savings under future uncertainties when Real Options are used instead of more traditional, precautionary approaches.

The impact of DEM data source on prediction of flooding and erosion risk due to sea-level rise

Digital elevation model (DEM) elevation accuracy and spatial resolution are typically considered before a given DEM is used for the assessment of coastal flooding, sea-level rise or erosion risk. However, limitations of DEMs arising from their original data source can often be overlooked during DEM selection. Global elevation error statistics provided by DEM data suppliers can provide a useful indicator of actual DEM error, but these statistics can understate elevation errors occurring outside of idealised ground reference areas. The characteristic limitations of a range of DEM sources that may be used for the assessment of coastal inundation and erosion risk are tested using high-resolution photogrammetric, low- and medium-resolution global positioning system (GPS)-derived and very high-resolution terrestrial laser scanning point data sets. Errors detected in a high-resolution photogrammetric DEM are found to be substantially beyond quoted error, demonstrating the degree to which quoted DEM accuracy can understate local DEM error and highlighting the extent to which spatial resolution can fail to provide a reliable indicator of DEM accuracy. Superior accuracies and inundation prediction results are achieved based on much lower-resolution GPS points confirming conclusions drawn in the case of the photogrammetric DEM data. This suggests a scope for the use of GPS-derived DEMs in preference to the photogrammetric DEM data in large-scale risk-mapping studies. DEM accuracies and superior representation of micro-topography achieved using high-resolution terrestrial laser scan data confirm its advantages for the prediction of subtle inundation and erosion risk. However, the requirement for data fusion of GPS to remove ground-vegetation error highlighted limitations for the use of side-scan laser scan data in densely vegetated areas.

Looking for evidence of climate change impacts in the eastern Irish Sea

Abstract. Although storminess is often cited as a driver of long-term coastal erosion, a lack of suitable datasets has only allowed objective assessment of this claim in a handful of case studies. This reduces our ability to understand and predict how the coastline may respond to an increase in "storminess" as suggested by global and regional climate models. With focus on 16 km of the Sefton coastline bordering the eastern Irish Sea (UK), this paper analyses available measured datasets of water level, surge level, wave height, wind speed and barometric pressure with the objective of finding trends in metocean climate that are consistent with predictions. The paper then examines rates of change in shoreline position over the period 1894 to 2005 with the aim of establishing relationships with climatic variability using a range of measured and modelled metocean parameters (with time spans varying from two to eight decades). With the exception of the mean monthly wind speed, available metocean data do not indicate any statistically significant changes outside seasonal and decadal cycles. No clear relationship was found between changes in metocean conditions and rates of shoreline change along the Sefton coast. High interannual variability and the lack of long-term measurements make unambiguous correlations between climate change and shoreline evolution problematic. However, comparison between the North Atlantic Oscillation winter index (NAOw) and coastline changes suggest increased erosion at times of decreasing NAOw values and reduced erosion at times of increasing NAOw values. Erosion tends to be more pronounced when decreasing NAOw values lead to a strong negative NAO phase. At present, anthropogenic changes in the local sediment budget and the short-term impact of extreme events are still the largest threat likely to affect coastal flooding and erosion risk in the short- and medium-term. Nevertheless, the potential impacts of climate change in the long-term should not be ignored.

Flood and coastal erosion risk management policy evolution in Northern Ireland: “Incremental or leapfrogging?”

Climate change poses a significant challenge for the future of Northern Ireland’s coast due to impacts that include, inter alia, mean sea level rise of between 13 cm and 74 cm by 2050. Whilst flooding is regarded as a major hazard in the United Kingdom (UK), to date Northern Ireland’s experiences of coastal flooding have been infrequent and less severe compared to those in England and Wales. Similarly, coastal erosion has historically been, and remains, only a minor concern in Northern Ireland. Partly as a result of this, Government administrative arrangements for Flood and Coastal Erosion Risk Management (FCERM) in Northern Ireland operate in the absence of any statutory provision for coastal erosion, as well as without formal or strategic shoreline management planning and any integrated flood and coastal erosion risk management policy. This paper provides a commentary on Northern Ireland’s approach to FCERM, comparing this with its UK counterparts, highlighting both congruence and divergence in policy evolution and development. It is noted that the recent EU Floods Directive has been a significant catalyst and that the current institutional landscape for FCERM is in flux.

Flood Insurance Coverage in the Coastal Zone

We explore behavior and test theory regarding the determinants of flood insurance coverage in the coastal zone using household-level data for nine southeastern counties. We use Tobit regression models to assess the importance and magnitude of insurance cost, risk factors, community characteristics, and household attributes on flood insurance purchase for residential building structures. Overall estimates indicate price inelastic demand, though subsidized policyholders are more sensitive to price and hold greater flood insurance coverage (controlling for value of asset at risk). We find support for rational choice in the coastal zone, with flood insurance coverage positively correlated in the level of flood risk. We find evidence that coastal erosion risk effects flood insurance demand, and that community level erosion hazard mitigation projects influence flood insurance holdings, with shoreline armoring appearing to act as a substitute and beach replenishment appearing to act as a complement.

A review of coastal risk management in the UK

This paper reviews the approaches that have been developed in the UK in order to deliver sustainable policies for managing risks from coastal erosion and flooding. One of the most important facilitators has been the adoption of a strategic framework at a national scale. This framework involves several scales of plans (shoreline management plans and strategy plans) as well as schemes. The recognition that funding sources are finite, and therefore need to be spent wisely, has also encouraged the development of more sustainable schemes. This has necessitated the development of a national appraisal methodology under which only the highest priority schemes achieve central government funding. The government also funds a national research programme to support flood and coastal erosion risk management. This paper gives examples of some of the outputs of this programme, which have included studies that have led to an improved understanding of coastal processes, coastal evolution, and risk levels, as well as the development of national data sets and management tools. The paper suggests some further improvements that could be made to the research programme. The discussion focuses on the likelihood of increasing choice of ‘managed realignment’ and ‘no active intervention’ policies in the future, their potential unpopularity with local stakeholders, and the current work under way to deal with these issues. The paper concludes with some thoughts on the priorities for coastal management over the next decade.

What really determines policy? An evaluation of outcome measures for prioritising flood and coastal risk management investment in England

AbstractIn April 2008, outcome measures (OM) replaced the old priority scoring system for the prioritisation of flood and coastal erosion risk management (FCERM) capital expenditure in England. In the context of the governance arrangements for this investment, the purpose of this paper is to provide a critical evaluation of this change: (1) to assess the ‘fitness for purpose’ of OMs for achieving government policies and goals in the delivery of sustainable FCERM and (2) to examine the capacity of the Environment Agency's proposed methodology to deliver projects against the targets set. The analysis concludes that it is far from clear whether the new OM system will deliver all the targets; offers any greater transparency, clarity or accountability; offers ‘better’ value for money across the spectrum of projects; and matches the ambitious policy aims of the government or the appraisal system within which it is a part. More positively, OMs do offer important progress and are suggestive of the ‘right’ direction of travel.

A stochastic method for predicting average beach shape

Coastal flooding and erosion is a key problem for coastal management, and is complicated by features arising from the combination of meteorological and morphological characteristics. Variability in the position and level of beaches introduces uncertainty into predictions of coastal flood and erosion risks. In the present study the problem of the variability of the shoreline in an embayment was addressed. A simple but efficient statistical method to estimate the mean of a crenulated-shaped bay from its equilibrium shape is proposed with input as the wave climate. The mathematical modelling is based on ensemble averaging and an equilibrium bay shape model. In this work, the effects of the coefficients in the crenulated-shaped bay on the estimation are investigated in a sequence of problems of successive generality. As a specific example, the method has been applied to Christchurch Bay in the UK. The results indicate that the ensemble average approach could provide an efficient means of estimating beach response to random wave conditions