Coastal Erosion Management Research Articles

Using virtual environments to improve the realism of choice experiments: A case study about coastal erosion management

Choice experiment surveys are commonly used to assess the general public׳s willingness to pay for different levels of environmental quality. However, respondents need to understand what they are valuing or they will make potentially wrong assumptions based on different experiences and frames of reference. Three-dimensional computer generated models or Virtual Environments (VE) have so far seen little use in economics research, probably due to the complexity and cost of developing and delivering them to study participants. The few studies that have used them find that VE are superior to static image presentations in helping people evaluate complex data. For this study we developed virtual environments for a choice experiment about coastal erosion management using free, easy-to-use software and Google Earth© satellite imagery and presented these to respondents as video tours. Our results indicate that the VE treatment reduced choice error, reduced left-right bias and improved respondent engagement and retention when compared with static images. There were also differences in WTP between the two groups.

A Choquet Integral with DEMATEL-based Method for Coastal Erosion Decision Problem

Background/Objectives: This study aims to investigate the cause-effect relationship risk factors associated to coastal erosion decision problem using a decision model based on Choquet integral and Decision-making Trial and Evaluation Laboratory (DEMATEL) method. Methods/Statistical Analysis: In this study, DEMATEL method is used to determine the cause-effect diagram of the risk factor. DEMATEL is known as one of the tools in dealing with digraph visualization of the degree importance for factor influence. Meanwhile, a Choquet integral is used to yield the aggregation among the subjective preference judgement made by the decision makers based on normal capacity. The process of combining a several preference values into a single value is called as an aggregation process. Findings: The Choquet integral DEMATEL-based approach is applied to coastal erosion decision problem to evaluate both interactive and causal relationship of the risk factors. There are two phases involve in this method. The first phase is to illustrate the relationship digraphs of selected risk factors and the implementation of weighted eigenvector matrix comparison in DEMATEL based method. The second phase takes into aggregation of the multi-criteria decision risk factors by fuzzy measure and Choquet integral to obtain the integrated weights value. From the study, it is indicated that shoreline changes has the highest score of Choquet integral by 1.8198 that contribute the most to the coastal erosion followed by relative sea level rise (1.5791), climate change (1.1917) and wave condition (0.9315). Application/Improvements: The feasibility of the developed method can be used to improve the risk factors of coastal erosion management and assessment.

Shoreline change analysis using end point rate and net shoreline movement statistics: An application to Elmina, Cape Coast and Moree section of Ghana’s coast

Most coastlines in the world are under the threat of erosion. As such many developed nations have instituted long-term measures to control the rate of change. However, along most developing nation coastlines, little attention is given to coastal erosion management. Ghana like most developing countries has little commitment to ensure the effective monitoring and management of coastal erosion. Consequently, many of its coastal communities and important historical monuments are now under severe risk to sea erosion. This study focuses on the shoreline evolution that occurred along the Elmina, Cape Coast and Moree coast of Ghana during a thirty-eight year period using available datasets that allowed the authors to discern between what happened between 1974 and 2005, and in the most recent years, between 2005 and 2012. Shoreline data from 1974, 2005 and 2012 were incorporated in Geographic Information System (GIS) using ArcGIS for analysis. The net shoreline movement and end point rate statistics were generated by ArcGIS together with Digital Shoreline Analysis System software extension. The study identified that in all the three epochs considered, there were a general erosion trend in the shoreline changes. This study has provided valuable and comprehensive baseline information on the state of the coastline in the Elmina, Cape Coast and Moree area which can serve as a guide for coastal engineers, coastal managers and policy makers in Ghana to manage the risk.

Coastal erosion management in Accra: Combining local knowledge and empirical research.

Coastal erosion along the Accra coast has become a chronic phenomenon that threatens both life and property. The issue has assumed a centre stage of national debate in recent times because of its impact on the coastal communities. Lack of reliable geospatial data hinders effective scientific investigations into the changing trends in the shoreline position. However, knowledge about coastal erosion, by the local people, and how far the shoreline has migrated inland over time is high in the coastal communities in Accra. This opens a new chapter in coastal erosion research to include local knowledge of the local settlers in developing sustainable coastal management. This article adopted a scientific approach to estimate rate of erosion and tested the results against perceived erosion trend by the local settlers. The study used a 1974 digital topographic map and 1996 aerial photographs. The end point rate statistical method in DSAS was used to compute the rates of change. The short-term rate of change for the 22-year period under study was estimated as -0.91 m/annum ± 0.49 m/annum. It was revealed that about 79% of the shoreline is eroding, while the remaining 21% is either stabilised or accreting. It emerged, from semi-structured interviews with inhabitants in the Accra coastal communities, that an average of about 30 m of coastal lands are perceived to have been lost to erosion for a period of about 20 years. This translates to a historic rate of change of about 1.5 m/year, which corroborates the results of the scientific study. Again this study has established that the local knowledge of the inhabitants, about coastal erosion, can serve as reliable information under scarcity of scientific data for coastal erosion analyses in developing countries.

An Extreme Event as a Game Changer in Coastal Erosion Management

ABSTRACT Sorensen, C.; Dronen, N.K.; Knudsen, P.; Jensen, J., and Sorensen, P., 2016. An extreme event as a game changer in coastal erosion management. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 700–704. Coconut Creek (Florida), ISSN 0749-0208. The construction of hard protection measures along the northeast coast of Sealand, Denmark, has gradually led to profile steepening, loss of beaches, and increased storm erosion. Although the problem has been addressed for decades no common solutions have been implemented yet. However, the impact of cyclone Xaver in December 2013 with severe coastal erosion led to collaboration between the involved municipalities to work on a coherent solution for the entire coastline that involves sand nourishments, renovation and optimization of hard protection structures, and the restoration of recreational values. ...

Coastal Erosion in Ghana: Causes, Policies, and Management

ABSTRACTCoastal erosion is a serious problem that affects the safety and livelihoods of many coastal dwellers along Ghana's coast. Despite the fact that coastal erosion is a natural phenomenon, erosion trends have been largely aggravated by human-induced factors. This study analyzed shoreline change rates for three neighbouring coastal communities in the Central region of Ghana; Elmina, Cape Coast and Moree. Two epochs were analyzed, 1974–2012 (medium-term) and 2005–2012 (short-term), using ArcGIS and Digital Shoreline Analysis System. Overall, the entire study area recorded average shoreline change rates of −1.24 myear−1 and −0.85 myear−1 in the medium-term and short-term period respectively. Less consolidated shoreline segments recorded higher erosion rates in both periods while cliffs and rocky segments experienced very little erosion or high stability. Because shorelines undergoing chronic erosion do not fully recover after short-term erosion events such as storms, facilities located close to such shorelines are threatened. Taking a proactive approach to coastal erosion management, such as coastal sand mining prevention, inter-sectoral land use management and adopting a construction setback approach may be prudent for the long-term management of the coast since this recognizes future shoreline changes and safeguards coastal landscape for other uses.

SIGIEC application: an integrated system for management of coastal erosion

The contrast between antrophogenic impact and ecosystem equilibrium is a very complex problem along coastal area. SIGIEC Application is a Decision Support System built on multidisciplinary studies composed by four components: Data Module, Geo Business Intelligence, Short Term Forecast System, Long Term Forecast System (Management DashBoard).Data Module permit to search and download several data types obtained by seismic survey, sedimentological analyses, geomorphoogical mapping, etc.Geo-business intelligence is able to analyze and merge data to derive new information and create new indicators.The short term forecast system is a web form that develop a scenario of potential risk of coast erosion versus weather forecast.The Management Dashboard gives the overall view of erosion phenomenon both in physical and economic terms with or without actions to management erosion. Finally, it compounds anthropic aspects and economic issues providing a cost/benefit analysis.

Development of New Coastal Erosion Management Method using Wave Direction Control System(1); New CeM: Tendency of Coastal Erosion and Measures, and Suggestion of New CeM

The coastal erosion is largely affected either by construction of port/fishery harbor, or coastal road revetment, which of each breaks the balance of longshore sand transport and one of cross-shore sand transport in coast, respectively. The detached type breakwater have been applied to control longshore sand transport as coastal erosion measures against construction of port/fishery harbor which cause longshore sand transport. However, it also produces new coastal erosion near area. Recently, the artificial reef (A.R.) is almost constructed on the standpoint of landscape as coastal erosion measures in Korea. A.R. is a submerged breakwater with wide crest and had developed to overcome weakness on the detached and submerged breakwaters. The wave is turned into strong longshore current passing through A.R., which occasionally results in scouring erosion around the A.R by increasing the water level at the back of A.R. In this study, we examined the coastal erosion occurrence by port/fishery harbor development and tendency of erosion measures. Also, problems of A.R. are examined with review on research and application example. Based on these, this study proposes new coastal erosion management method, ‘New CeM’, for erosion measure in coast where balance of longshore sand transport is broken. Instead of directly protecting against the ingressive wave, the new method is the wave direction control system for correcting the imbalance of longshore sand transport by obliquely installing breakwater of detached type. The performance and physical phenomenon of New CeM will be introduced later.

Public perceptions of beach nourishment and conflict management strategies: A case study of Portonovo Bay in the Adriatic Italian Coast

Conflicting interests, goals, and value often shape the stakeholders' positions concerning coastal erosion management strategies. Analyses of stakeholders' perceptions of beach nourishment and conflict management strategies are lacking. Since the involvement of key stakeholders is crucial to ensure successful integrated coastal management, the aim of the current study was to investigate the stakeholders’ perceptions of beach nourishment and conflict management strategies in the community of the Portonovo Bay in the Adriatic Italian coast. During 2013, detailed, semi-structured interviews were conducted with members of the community and stakeholders regarding beach nourishment and related conflict management strategies at Portonovo Bay. The results revealed that respondents not only reported different perceptions, values, and interests but also their main goals were dissimilar. We found polarized opinions concerning antagonistic value systems shared by the participants, which were associated with quite opposed perceptions of existence and severity of the problem and efficacy and harmfulness of beach nourishment. The perceptions of the respondents were categorized into two major categories that reflect two of the philosophical views of the human-environment relationship: ecocentrism versus anthropocentrism. Four categories of proposed conflict resolution strategies were identified: (a) information, (b) dialogue and contact, (c) compromise, and (d) no solution. The adoption of a participatory approach and the implementation of conflict management skills and technique can be considered important elements of coastal management.

Managing coastal erosion hotspots along the Elmina, Cape Coast and Moree area of Ghana

Like most coastlines the world over, Ghana's coast has been receding, requiring management interventions to protect coastal communities and assets of national importance. In order to adopt sound management interventions that would have a long lasting positive impact on the coastal zone, an understanding of the historic pattern of coastline change and coastal dynamics is required. This paper presents an analysis of the historic trends in coastline changes along the Elmina, Cape Coast and Moree area of Ghana using three shoreline data that spans a period of 38 years using ArcGIS and Digital Shoreline Analysis System tools. The study found that the Elmina, Cape Coast and Moree area had been eroding at a rate of 1.22 m/year ± 0.16 m from 1974 to 2012. It was identified that the widespread practice of beach sand mining in the area has significantly contributed to the erosion of several sections of the coastline. The study also identified the lack of an existing coastline management plan for Ghana's coast as the reason for the poor coastal erosion management techniques often used by coastal managers in response to the threat of coastal erosion, which eventually causes an acceleration of local erosion rates. The study finally makes a case for the adoption of a proactive and coordinated coastline management plan for Ghana's coast similar to that of the United Kingdom shoreline management plans because of the numerous known advantages.

Sand Dynamics as a Tool for Coastal Erosion Management: A Case Study in Darwin Harbour, Northern Territory, Australia

Darwin Harbour, Northern Territory, Australia, is a semi diurnal macro-tidal embayment that is situated in a cyclone prone area. The tidal variations range up to 8 m with a mean tidal range of 3.7 m. The coastal area consists of mangrove fringes, sandy beaches, tidal flats, rocky shore platforms and coastal cliffs. The main morphological changes are movement of the sandbars and erosion of beaches and coastal cliffs. Sea level rise due to climate change and more intense cyclones and storm surges may exacerbate these processes with detrimental impacts on the coast and the adjacent city, particularly when occurring at high tide. To assist with coastal erosion management, a greater understanding of morphological changes is required. A two-dimensional depth averaged finite-element hydrodynamic model (RMA-2), coupled with a sediment transport model (RMA-11) from Resource Modelling Associates, have been used to deduce the sources and spatial patterns of sand erosion and deposition in the harbour. Geochemical analysis is also used to characterize the sand source(s). This paper presents hydrodynamic simulations focusing on culturally and recreationally significant beaches in Fannie Bay. Simulations indicate that the Cullen Bay sandbar is an indirect sand source replenishing Fannie Bay beaches. Respective geochemical results also show similar Rare Earth Element contents of the sand in the area. Considering the fast pace of development in and around Darwin Harbour, this study is essential in providing a fundamental understanding of coastal processes and to assist coastal and shoreline management in a tropical estuary.

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.

Erosion protection options of a muddy coastline in Thailand: Stakeholders' shared responsibilities

Protecting a muddy coastline from erosion is not an easy task since various constraints complicate the issue. This study presents a story on the management of muddy coastal erosion by utilizing a case study of the muddy coastline along Chachoengsao province, Thailand. The study started with collecting and analyzing site-specific fundamental data such as coastal physical, environmental, and socio-economic information. The erosion severity was examined using historical satellite imagery. Stakeholder analysis was applied to identify who was responsible for the coastal protection and why. In an attempt to derive appropriate coastal protection measures that were acceptable to every party, existing coastal structures were surveyed and categorized into three groups—low-crested revetment, sand-filled geocontainer, and bamboo fencing—that were assessed for their advantages and shortcomings. Government units responsible for each type of structure were interviewed. Their responses reflected their constraints as well as the reasons behind their actions. Opinions from coastal communities were evaluated during formal meetings as well as by a questionnaire. The final acknowledged coastal protection measure was a combination of spaced low-crested revetments and low-crested detached breakwaters, with bamboo fencing being optional. A detailed design of the structures was subsequently undertaken and received positive acceptance from the stakeholders.

Coastal Erosion and Management in the People’s Republic of China

China has a coastline of 32,000 km, third of which is occupied by sandy coast. According to the latest report of the State Oceanic Administration (SOA, PRC), 3,255 km soft coast is suffering from severe coastal erosion, 76% of which is sandy coast, the rest contributed by muddy coast. Coastal erosion results in heavy land loss and aggravates financial burden, which is unacceptable. Coastal erosion management of China, aiming at facilitating the sustainable relationship between socioeconomic development and protection of coastal environment, is a systematic process of using scientific technology, administrative and economic policy to realize a socialized, scientific and informative coastal erosion management system in order to minimize the adverse impacts of coastal erosion hazard. Since 1990's, the implementation of coastal erosion management in China has began, the theory and practice of which were depicted by lots of literatures. The causes and effects of coastal erosion, coastal erosion assessment and management, natural disaster risk assessment, geological characteristics of coastal disaster and coastal erosion mitigation measures were all involved in these literatures. The Chinese Offshore Investigation and Assessment (COIA) project launched in 2007 has accomplished the assessment of coastal erosion hazard and provided mitigation measures of hard and soft structures for controlling coastal erosion. The project of Sandy Coast Nourishment and Restoration in China (SCNR) will be finished in 2012, its main objective is to develop and test beach nourishment as a measure for reducing erosion along the sandy coast of China, based on the available scientific knowledge and practical experiences. These works did provide large amounts of fundamental data and successful experience, which guide the managers and researchers to find a more harmonious process for risk reduction of coastal erosion. Presently, the available mitigation measures for coastal erosion in China are threefold: 1) managed realignment, the most preferred measure, containing construction of SBL (setback line), transformation of LUCC (land use/cover change) and establishment of the coastal natural reserves; 2) advance the line, building new defenses on the seaward side of the original defenses such as reclamation; 3) hold the line, the most popular measure, including soft nourishment and hard engineered structures. Two thirds of Chinese mainland coastline is protected by seawall; soft nourished coastline in China amounts to 10,400 m, nourished volume more than 2 million m 3 by the end of 2009 and 20 mangrove or coral reef natural reserves has been established along the subtropical coastal areas. These mitigation measures hold the existing shoreline and keep the safety of habitants and constructions from destroying. The successful implementation of coastal erosion management in China does not imply that all problems have been solved. Issues such as climate change, development in societal pressure on the coast and increasing knowledge on coastal system, constantly challenge the existing approaches. I hope to share the coastal erosion and management status in China with people interested and welcome advice and cooperation from researchers and managers.

Public perceptions of managed realignment strategies: The case study of the Ebro Delta in the Mediterranean basin

Managed realignment strategies, based on working with physical processes and dynamic environments, are gaining weight in sustainable coastal erosion management. However, this kind of innovative adaptive strategy can give rise to major social conflicts. A proposal to implement managed realignment in the Ebro Delta in Spain is provoking intense social conflict between different socioeconomic sectors. This qualitative study, based on semi-structured interviews with key stakeholders, analyses social perceptions of three management strategies aimed at coping with coastal erosion in the Ebro Delta in order to throw some light on the main barriers to a managed realignment strategy. The results reveal the complexities of the local conflict and highlights issues such as mistrust of public authorities and limited understanding of managed realignment. A lengthy hold-the-line tradition in coastal policies in Spain and local idiosyncrasies contextualize a problem that was initially perceived as one of the typical conflict of interest between conservationists and the primary economic sector. Efforts to provide transparent information, improve participation and build trust are suggested in order to be able to implement managed realignment strategies with the cooperation of the local community.

Coastal Erosion Management in Algarve (Portugal) — A Beach Nourishment Case Study

ABSTRACT PROENCA, B., OLIVEIRA, F.S.B.F and SANCHO, F., 2011. Coastal Erosion Management in Algarve (Portugal) — a Beach Nourishment Case Study. In: Micallef, A. (ed.), MCRR3-2010 Conference Proceedings, Journal of Coastal Research, Special Issue, No. 61, pp. 328–334. Grosseto, Tuscany, Italy, ISSN 0749-0208. In the Portuguese southern coast, national and international appeal turns it into a highly relevant area concerning the country's economy. Vale do Lobo is a resort located in the centre of this coast, where the beach has been suffering from erosion problems for several years now. Local interventions have been executed in order to prevent the erosion of the beach, yet the efficiency of such strategy has not been verified. This study's main purpose is to enable a better understanding of the evolutionary trends of the coastline between the Quarteira and Ancno inlet and to analyse the efficiency of the beach nourishment interventions as a protection technique for a coastal environment with the wave energ...

Implementation of coastal erosion management in the Netherlands

The Netherlands is a low-lying country, in which 9 million people are living below sea level and 70% of the gross domestic product is being earned in areas below sea level. Therefore, protection against flooding is traditionally the primary focus of coastal policy in the Netherlands. Analysis shows that characteristics of Dutch coastal management very well comply with the recommendations and key concepts to support sustainable coastal management as issued by the EU in 2004 (EUROSION). Sediment management represents the core of erosion management in the Netherlands; key concepts like resilience, coastal sediment cells, favorable sediment status and strategic sediment reservoirs, are important building stones. Development and implementation of coastal erosion management in the Netherlands, has implicitly been guided by a systematic Frame-of-Reference. Characteristics of this approach are the definition of clear objectives at different levels (i.e. strategic, tactical and operational) and an operational decision recipe related to policy development and implementation. Application of the Frame-of-Reference to current problems and challenges in Dutch coastal management indicates its ability to reveal shortcomings of the existing approach, and to explore potential solutions. Where EUROSION offers important concepts to define coastal erosion management, the Frame-of-Reference offers a tool to discern different objectives and responsibilities. The combination of both strongly supports implementation of coastal erosion management.

Concepts and science for coastal erosion management – An introduction to the Conscience framework

The main objective of the Conscience project was to develop and test concepts, guidelines and tools for the sustainable management of erosion along the European coastline, based on the best available scientific knowledge and on existing practical experience. Four concepts are potentially capable of providing the nexus between scientific knowledge and management: coastal resilience, coastal sediment cell, favourable sediment status and strategic sediment reservoir. The project has tested the use of these concepts and found that they are useful, provided that they are positioned and linked within a logical structure that we shall call the Conscience “Frame of Reference”, defined in time and space and supported through data and monitoring. Practical experience in six coastal sites in Europe has shown that the use of this Frame of Reference together with these concepts can make management objectives explicit and transparent. It can therefore support the design of an appropriate, resilience based coastal erosion management practice.

The role of coastal setbacks in the context of coastal erosion and climate change

Coastal erosion and storms represent a source of risk for settlements and infrastructure along the coast. At the same time, coastal natural assets, including landscape, are threatened by increasing development mainly driven by tourism. The Mediterranean coast is especially vulnerable to these processes, considering its high biological and cultural diversity. An additional challenge is represented by climate change, as it will force coastal communities to apply more or less drastic adaptation strategies. Coastal setbacks, used to protect coastal communities and infrastructure from storms and erosion, and to preserve coastal habitats and landscapes from degradation, is one of the main instruments suggested by the Protocol on Integrated Coastal Zone Management of the Barcelona Convention, entered into force on the 24 of March 2011. Its implementation has the potential to influence coastal policies in other regions, such as the neighbouring Black Sea. The CONSCIENCE project has formalized concepts and conducted specific studies to provide new tools for coastal erosion management practice. The objective of this paper is to present a synthesis of the research conducted into coastal setbacks for coastal erosion management and climate change adaptation. This is done by analysing the requirement of the Protocol, current processes and management practices in two case study areas (Costa Brava Bays in Spain and Danube Delta, in Romania) and the new challenges posed by climate change.

Efficiency of an integrated habitat stabilisation approach to coastal erosion management

The present paper describes the technical solution adopted for habitat stabilisation as an integrated approach to erosion mitigation aimed at improving ecological and environmental aspects of the tropical and subtropical shorelines. Any man-made structure on the beach could have an environmental impact on the habitat and the associated biota. However, when the habitat is considered in the design process, a coastal erosion management plan can provide an effective means of coastline stabilisation and habitat enhancement. Therefore, in this study a combination of low crested breakwaters and a mangrove restoration plan was applied to an intertidal beach on the west coast of the state of Selangor, Malaysia. The study was aimed at protecting the beach and enhancing the habitat. The presence of the breakwater resulted in sediment deposition on the beach and the substrate elevation increased to a height appropriate for mangrove establishment. The calm area protected by the breakwater was also conducive to restoration work on the exposed coast. The approach provided suitable conditions for coastal rehabilitation, facilitating the natural recovery process of the coastal ecosystem.