Vulnerable Coastal Areas Research Articles

An Integrated Bayesian Risk Model for Coastal Flow Slides Using 3-D Hydrodynamic Transport and Monte Carlo Simulation

The literature suggests two forms of flow slides: breaching and liquefaction. Both forms of failure have comparable ultimate circumstances, but the progression and sand movement mechanisms of breaching failure diverge from those of liquefaction. The first type, breaching, occurs in densely packed sand and is characterized by slow sand grain discharge throughout the dilation of the failing soil particles and negative excess pore pressures. The latter form, known as liquefaction, is the process by which a mass of soil abruptly begins to behave like a flowing liquid, and as a result, it can flow out across overly mild slopes. The process begins in compacted sand and is linked to positive surplus pore water pressures that are caused by the compaction of the sand. Despite the available literature on flow slide failures, our understanding of the mechanisms involved remains limited. Since flow slides often begin below the water surface, they can go undetected until the collapse reaches the bank above ground. The complexity of flow slides requires the use of cutting-edge technological instruments, diving equipment, advanced risk assessment, and a variety of noteworthy probabilistic and sensitivity analyses. Hence, we developed a new sensitivity index to identify the risk of breach failure and vulnerable coastal areas to this risk. In addition, we developed a sophisticated hybrid model that allows for all possibilities of flow slides in sync with random variables used in this new sensitivity index. In this new hybrid model, three distinctive models exist. The 3D Hydrodynamic Model addresses waves, wind, current, climate change, and sediment transport. The Monte Carlo Simulation is responsible for sensitivity analysis, and the Bayesian Network focuses on joint probabilities of coastal flow slide parameters of this new index that incorporates all environmental parameters, including climate change. With the assistance of these three models, researchers aim to: (a) expand the application scope by presenting a method on coastal flow slides; (b) consider different particle diameters corresponding to critical angle slope failure; (c) analyze variables that can play a pivotal role in the flow slides; and (d) present a methodology for coupling coastal flow slide projections with reliable outcomes. The hybrid model incorporates random variables of retrogressive breach failures, and the new risk index considers their ranges to control the simulation. The use of such a hybrid model and risk index offers a robust and computationally efficient approach to evaluating coastal flow slides.

BLUE LINES AS A MEANS OF GRAPHIC FIXATION BETWEEN WATER BODIES IN TOWN PLANNING DOCUMENTATION

In this article the purpose of the Blue Lines of Limitation as a fixation of the spatial boundaries of water bodies in the urban planning activity is considered. The peculiarities and importance of the use of Blue Lines as boundaries of the water area for maintaining urban planning discipline are indicated. Preservation of the boundaries of water areas in an urbanized environment requires the introduction of a separate urban planning restriction in the urban planning documentation. Along with the Red, Blue, Green and Yellow lines, which are already "working" in urban planning documentation, the Blue lines will graphically display the borders of the water area, regulating the regulation of urban planning activities in certain territories, which will contribute to urban planning discipline and the preservation of water ecosystems.
 Blue lines can graphically fix the boundaries of the water area to limit urban planning and economic activity. Our proposal is to introduce the concept of Blue Lines into the new edition of DBN B2.2-12-202… «Planning and Development of Territories» in the following wording: "Boundaries of the coastline (cut of water) on the natural or artificially created water area of water bodies (reservoirs and water courses) - the internal boundaries of the water protection zone with defined regimes and rules of economic activity are defined by blue lines."
 The development of district planning schemes, general plans of settlements, detailed plans of the territory (M 1: 25000, 1:10000, 1: 2000) graphically, with the help of blue lines, should indicate:
 - cuttings of existing and artificially created reservoirs; - section of direction, channel deepening; - changing the contour of reservoirs in case of their revitalization, etc.
 Fixing the spatial boundaries of the water area with the help of Blue lines will fulfill the tasks of urban planning regulations of economic activity, which will contribute to the preservation of the natural component of the water ecosystem in an urbanized environment.
 To preserve and protect water bodies in an urbanized environment, effective urban planning restrictions are necessary. Urban planning restrictions contribute to the preservation of our settlements from chaotic and disharmonious construction, make the urban space safe and comfortable for residents. The designation of the Blue Lines is a tool for preserving the natural component in the urbanized environment, which will help solve the problem of balanced, rational and harmonious use of water areas and vulnerable coastal areas.

An ensemble-based assessment of bias adjustment performance, changes in hydrometeorological predictors and compound extreme events in EAS-CORDEX

The effectiveness of adaptive measures tackling the effects of climate change is dependent on robust climate projections. This becomes even more important in the face of intensifying extreme events. One example of these events is flooding, which embodies a major threat to highly vulnerable coastal urban areas. This includes eastern Asia, where multiple coastal megacities are located, e.g. Shanghai and Shenzhen. While the ability of general circulation models (GCMs) and regional climate models (RCMs) to project atmospheric changes associated with these events has improved, systematic errors (biases) remain. This study therefore assess capabilities of improving the quality of regional climate projections for eastern Asia. This is performed by evaluating an ensemble consisting of bias adjustment methods, GCM-RCM model runs and future emission scenarios based on representative concentration pathways (RCP) obtained from EAS-CORDEX. We show that bias adjustment significantly improves the quality of model output and best results are obtained by applying quantile delta mapping. Based on these results we evaluate potential future changes in crucial hydrometeorological predictors, univariate extreme events and compound extreme events, focusing on high wind speeds and extreme precipitation. Key findings include an increase in daily maximum temperature of 1.5 to nearly 4 °C, depending on the scenario, as well as increased levels of precipitation under RCP 8.5. Furthermore, a distinct intensification of extreme events including high temperatures and heavy precipitation is detected and this increase exceeds the increase of the overall mean of these predictors. The annual number of compound events including heavy precipitation and extreme wind speeds shows a significant increase of up to 50% for RCP 8.5 in the South China Sea as well as the adjacent coastal areas.

Coastal Geomorphology and Geospatial Beach Profile Assessment for East Coast Monsoonal Coastlines.

The main concern for this research is slope estimation and the beach profiling with verification sensor-based remotely data (high spatial resolution). Thus, surveying and satellite extraction data need to be accurat. It had been proven to support the relationship between coastal erosion with beach slope changes along Kuantan, Pahang. Therefore, the actual coastline can be mapped from last vegetation features and determine physical condition of beach on coastal habitable land where the baseline has been changes due to sea-level rise event. Hence, the aim of this study is to monitor beach profile using high spatial resolution remote sensing imagery and GIS techniques to distinguish slope estimation from different sources in Kuantan, Pahang Site-verification are done to identify beach slope profiling along Kuantan coastline, Pahang. The objectives of this research are i) to generate coastal slope estimation and beach profile in year 2006 and 2014, ii) to quantify the estimated and observed beach slope from IFSAR data and slope site surveying (by NAHRIM) and iii) to visualise in 3-D view of coastal slope profile derived using IFSAR data. The accuracy values provided for the measurements made in open area, undisturbed area with slopes less than 10 %. From early reconnaissance of Kuantan beach, most of the area are flat and sandy profile to which are suitable for this application. Besides, we found out this method are reliable to produce appropriate slope profile along identified areas in selected Pahang coastline. The findings may indicated a better strategy for monitoring coastline changes is needed especially for vulnerable coastal erosion areas for future sustainable coastal management.

Ecosystem Service Value Response to Different Irrigation and Drainage Practices in a Land Development Project in the Yellow River Delta

The potential for development of saline land is enormous; the concept has recently attracted great scientific attention regarding its use and development. It is especially crucial to consider the issue of ecological balance when carrying out large-scale land remediation in the Yellow River Delta region since the saline land there is rich in resources and is also typically an ecologically delicate area. In order to quantitatively estimate the value of ecosystem services under various irrigation and drainage modes, this paper uses an undeveloped land development project in the Yellow River Delta as an example, simulates five different irrigation and drainage modes, and combines the market value method and the calculation method of factor equivalents. A quantitative estimation of the ecosystem service value under different irrigation and drainage modes is carried out, exploring the impact of different irrigation and drainage modes on the ecosystem from the perspective of ecosystem service value. The findings revealed that while the “Pipeline irrigation + concealed pipe” irrigation and drainage model increased the area of cultivated land by 4.04 km2, the overall ecological value increased by only Renminbi (RMB) 6.707 × 106. It is clear that only an increase in the area of cultivated land will not increase the ecological value as a whole. Through comparison, it is found that the ecological value of ‘Pipeline irrigation + open ditch’ irrigation and drainage pattern increases the most, which is RMB 28.405 × 106. It can increase the area of cultivated land and protect the ecological benefits to a greater extent, which can better meet the requirements of the current comprehensive development. The study’s findings can serve as a foundation for the sustainable development of the area and the scientific selection of development in ecologically vulnerable coastal areas.

Economic valuation of ecosystem services for application of circular economy approach in conservation of Kundapura mangroves of Karnataka, India

AbstractCoastal areas are overwhelmingly rich in resources and support the livelihoods of the local communities. Coastal mangrove ecosystem provides a wide range of goods and services for human needs and wellbeing. To value conservation benefits of 252.29 ha extent of Kundapura mangrove ecosystem's goods and services, an economic valuation study was conducted using Systems of Environmental Economics Accounting (SEEA) framework. In total, seven ecosystem benefits were identified under provisioning, regulating and cultural services categories of SEEA. Identified baskets of benefits are fisheries, timber, fuelwood, protection against storms and floods, water quality maintenance, carbon sequestration, recreation and tourism. Out of seven benefits, the present study has found that the disturbance regulation benefit's contribution, which is about 92.65% of overall benefits with its economic value, US$1.786 million per year (17.86 lakh). Disturbance regulation benefit has significant role in reducing the impact of vulnerability from coastal hazards and sheltering 4354 individuals of population occupying 1088 houses. Despite that fact, Kundapura mangrove's assets are being degraded by various negative externalities. Particularly reclamation for aquaculture purpose and consequent discharging of the effluents, and dumping of sludge and municipal solid wastes (MSWs). These externalities would exacerbate the environmental problems and impacts on the flow of benefits. Hence, circular economic approach as pioneering to renovate the current linear system into circular one through 3R's strategy (reduce, reuse, and recycle) in the process of production, distribution, and consumption of ecosystem goods and services. This research paper explains about the application of circular economic approach in conservation management by assessing economic valuation of Kundapura mangrove's specific services. This approach is expected to finally result in aiding decision‐making process to limit the quantity of polluting residuals and control the degradation activities thereby sustain the mangroves in good health. Further the regeneration and expansion of mangrove extent would improve the mangrove‐dependent fishery, promote sustainable tourism, and maximize the coastal protection and economic benefits in this region. This will go a long way in sustaining the health of the otherwise fragile mangrove ecosystem of Kundapura coastal stretch, which is under the category of Critically Vulnerable Coastal Areas (CCVAs), identified under CRZ of India.

Land Subsidence Detection in the Coastal Plain of Tabasco, Mexico Using Differential SAR Interferometry

Land subsidence (LS) increases flood vulnerability in coastal areas, coastal plains, and river deltas. The coastal plain of Tabasco (TCP) has been the scene of recurring floods, which caused economic and social damage. Hydrocarbon extraction is the main economic activity in the TCP and could be one of the causes of LS in this region. This study aimed to investigate the potential of differential SAR interferometric techniques for LS detection in the TCP. For this purpose, Sentinel-1 SLC descending and ascending images from the 2018–2019 period were used. Conventional DInSAR, together with the differential interferograms stacking (DIS) approach, was applied. The causes of interferometric coherence degradation were analyzed. In addition, Sentinel-1 GRD images were used for delimitation of areas recurrently affected by floods. Based on the results of the interferometric processing, several subsiding zones were detected. The results indicate subsidence rates of up to −6 cm/yr in the urban centers of Villahermosa, Paraíso, Comalcalco, and other localities. The results indicate the possibility of an influence of LS on the flood vulnerability of the area south of Villahermosa city. They also suggest a possible relationship between hydrocarbon extraction and surface deformation.

An ASBPA White Paper: U.S. community perspectives on coastal flooding

Coastal flooding, from both extreme events and sea level rise, is one of the top management challenges facing U.S. coastal stakeholders today. The intensity of coastal flooding is expected to increase with global sea level rise. This paper focuses on flooding challenges from the perspective of coastal communities. The myriad of flood mitigation strategies that have been implemented across the U.S. vary based on a multitude of factors including spatio-temporal scale of the coastal flooding hazard. ASBPA administered a survey of 106 coastal stakeholders from around the U.S. to assess specific community challenges and needs related to coastal flooding in late 2021. A majority of respondents indicated that their community includes an underserved population or neighborhood (54%) or nearby communities do (25%). While the vast majority of survey respondents indicated that flooding was a major challenge, only 24% of respondents’ communities have a coastal flooding adaptation plan. Improvements to drainage systems are the most commonly implemented gray infrastructure strategy in the Southeast and Gulf coast regions. Respondents from all regions noted that beach and dune restoration has been the most widely implemented nature-based flood mitigation strategy. Interest is now high in other nature-based solutions with application in low-lying, vulnerable coastal areas such as thin-layer placement on marshes, living shorelines, and hybrid projects on estuarine shorelines. This paper does not provide an exhaustive review of the science, forcings, or policies on coastal flooding in the U.S.; rather, it captures the perspectives of coastal communities and aims to inform and prioritize future research investments related to coastal flooding.

Compound Wind and Precipitation Extremes in Global Coastal Regions Under Climate Change

AbstractCompound wind and precipitation (CWP) extreme events can cause a significant increase in socio‐economic loss in coastal regions. This study investigated the potential impact of climate change on CWP events using Coupled Model Intercomparison Project model outputs for the coastal areas impacted by tropical cyclones on a global scale. We identified global hotspots of higher dependence between extreme wind and precipitation events. Under climate change, the results show a substantial increase in precipitation extremes compared to individual wind extreme events. The likelihood of CWP events under climate change indicates an increase (about 40%–50%) in most coastal regions in North Atlantic, East, and South Asia. The results of this study can help to identify hotspot regions under climate change and further assist in minimizing the impact of future disasters in vulnerable coastal areas.

A synthetic water-heat-vegetation biodiversity nexus approach to assess coastal vulnerability in eastern China

Climate change pressure and biodiversity degradation in coastal regions have caused an increase in urban vulnerability. Current coastal vulnerability studies fail to consider the interactions among the perturbations. Increases in such interactions contribute to the indeterminate changes in the ecosystem productivity and impact on human well-being. Therefore, by integrating water, heat, and vegetation biodiversity (WHB) indicators using catastrophe theory in the study, the interaction among subsystems was explored to expound on the multi-effect of the urban. The results showed that (1) the overall vulnerability of China's coastal cities has increased, and high-value areas were mainly distributed in the three southern provinces; (2) the spatial-temporal pattern of vulnerability was highly heterogeneous. As low-low clusters, Shanghai and its surrounding cities exhibited spatial aggregation characteristics; (3) social, physical and financial capitals were the first three main adaptive capacity factors. The distance-based linear model (DistLM) evidenced that per capita GDP, and road density explained about 30 % and 10 % of the difference in vulnerability variation. The proposed framework could help decision-makers detect how vulnerable coastal areas exposed to WHB impacts are, with crucial implications for future sustainable management.

Assessing household perception, autonomous adaptation and economic value of adaptation benefits: Evidence from West Coast of Peninsular Malaysia

Climate change is causing sea-level rise, intense and frequent storm surge flooding, and significant shoreline erosion in Malaysian coastal areas. Consequently, coastal properties, infrastructure, and livelihoods are threatened. It has become apparent that adaptation at the household and community level is necessary to offset the adverse impacts of coastal hazards. The community needs to be made aware of the risks, acquire knowledge about adaptation options, and be empowered to take their own actions. Public perception and preference are therefore crucial for design and implementation of effective planning for climate change. Thus, this study assesses households' perception, adaptation measures and empirically estimates willingness to pay and preference for planned adaptation measures to guide policy instruments through public engagement. In Malaysia, ten highly vulnerable coastal areas in the Selangor coast were surveyed at the household level (n = 1016) through face-to-face interviews using a structured questionnaire. Regarding households’ perception and adaptation methods, most of the households in the highly exposed areas perceived less risk of inundation and sea-level rise threat and adopted less proactive adaptation and limited risk reduction behaviours during the extreme event. The study found that 66.9% of households were willing to pay for planned adaptation measures despite the limited income capabilities and in favour of moderate adaptation (23.9%). The binomial and ordinal regression results indicated that the probability of willingness to pay for planned adaptation measures significantly increases with age, prior exposure to coastal hazards, awareness, risk perception, community participation, being affected by property damage and loss of income due to extreme events. With increased monthly household income and access to telecommunication services, households will probably pay higher for better adaptation measures. A significant amount of perceived yearly adaptation benefits in the coastal districts revealed the economic value of extensive (22,969.50 MYR/5462.43 USD), moderate (21,853.20 MYR/5196.96 USD) and minimal adaptation measures (8022.90 MYR/1907.94 USD) that can be utilised to incentivise coastal adaptation plans. The findings suggest policies to incorporate social values to reduce vulnerability, enhance community resilience, and contribute to the knowledge gap of adaptation research in the coastal areas.

Systemic vulnerability of coastal territories to erosion and marine flooding: A conceptual and methodological approach applied to Brittany (France)

The attractiveness of the coasts tends to increase their exposure to erosion and marine flooding risks. This exposure is exacerbated by the effects of climate change, in particular sea level rise. To contribute to strategic thinking on the vulnerability of coastal areas, it is essential to develop, share and collectively maintain relevant knowledge on risks. This article will present the thinking behind the setting up of a coastal risks observatory in Brittany, a region located in north-western France. It relies on a conceptual approach to systemic vulnerability based on four components: hazards, assets, management, and social representations. Hazards and assets underpin the notion of risk and tend to increase the vulnerability, management tends to mitigate it, and representations can play a part in increasing or decreasing it depending on the context. To understand and analyse this system of vulnerability, our approach is based on the generation of a set of 62 indicators combined into different types of indices. A web-GIS interface was developed to navigate through and map this system of vulnerability. The difficulties associated with this type of synthetic approach will be discussed, whether they are related to data availability, to the links between scientific research and operational territorial management requirements, or to an understanding of the dynamics of all of the vulnerability components and their interactions. Ultimately, the approach developed has been successful in mobilising scientific and operational stakeholders around the co-construction of a diagnosis of territories with regard to their vulnerability to coastal risks.

A Vision of Sustainable Design Concepts for Upgrading Vulnerable Coastal Areas in Light of Climate Change Impacts: A Case Study from Beirut, Lebanon

Rapid urbanization combined with the effects of climate change has increased the vulnerability of poor urban communities to natural hazards, particularly to informal settlements located in coastal areas. Apart from socio-economic challenges, the effects of climate change threaten the very existence of these settlements. They are particularly vulnerable due to their poor structural quality and lack of adequate infrastructure to mitigate the consequences of any natural event. The article highlights an informal settlement belt, located on the coastline of the southern suburb of the capital Beirut. This area is an example of a complex urban, social, and economic structure. As a result, this research speculates on the possible sustainable design solutions and tested development strategies through urban, architecture, and landscape design proposals, derived from interventions that succeed in facing similar challenges compatible with the studied context. The aim is to advocate for comprehensive consideration and transformation of coastal informal settlements that can be used to encourage neutralizing the obvious challenges of climate change in urban settings. Therefore, planning specifications and quality aspects for future coastal informal settlements are proposed and extracted. The research involves analysis of qualitative data rather than quantitative data, as there is not much definite information available in terms of statistics, such as review of publications and grey literature. The scope of the study ranges from microscale improvement to providing usable and accessible city-wide ecological urban settings and sustainable spaces with new standards for coastal informal settlements as a potential backbone.

Current and Future Salinity Intrusion in the South-Western Coastal Region of Bangladesh

The southwestern coastal regions of Bangladesh (SWCRB) are highly exposed to saltwater intrusions brought about through cyclones and storm surges. These salinity intrusions are contributing to soil and water salinity in the coastal areas. This study aimed to determine the impact of these salinity intrusions on the quality of water and soil in three vulnerable coastal areas. In this investigation, water and soil samples were collected and analysed for pH, electrical conductivity (EC) and other trace elements. The analysis found many of the parameters to be higher than the recommended values. The study found that in soil samples there was a significant correlation between OM and ECe dS/m, as well as K and TN; and a highly significant correlation between TN and OM. This study further examined the historical salinity data at low and high tides to determine any patterns occurring alongside storm surges and cyclones. Water salinity statistics were obtained from the three locations of the Bangladesh Water Development Board (BWDB), which neighbours the study area. A Digital Evaluation Model (DEM) predicts the salinity induced by storm gushes in the corresponding impacted zones. Lastly, the study compared projections for future storm surges at current and predicted sea levels. Potential storm gushes circumstances from 1 to 9 m can impact up to 33% of the nation and 97% of the Shyamnagar Upazila. The occurrence of cyclone-related storms will increase and make cultivation and settlement in the region difficult. The predicted sea-level rises and saltwater contamination will intensify the adverse effects of salinity.

Analysis of environment, socio-economic, and stakeholder partnership for integrated coastal management in Semarang City, Indonesia

Land transformation is the main factor that may increase ecological vulnerability in coastal areas in Semarang City, Indonesia. Therefore, environmental damage in coastal areas should be restored using an integrated management strategy based on the ecosystem, social and economic condition, as well as stakeholder partnership. This research aimed to measure the resilience score of environmental and socio-economic conditions and to identify stakeholder partnership in arranging integrated coastal area management in Semarang City. A descriptive observational study was conducted in Mangkang Kulon and Tugurejo Sub-district, Tugu District, Semarang City using in-depth interviews, field observations and survey-mapping. The ecological conditions data was collected using image analysis of aerial photographs following the concept of environmental and geophysical. Meanwhile, the social-community conditions data were diagnosed using a socio-economic assessment. The result showed that changes in the coastline occured due to the disappearance of some area of mangrove that were turned indented close to the ocean. However, the socio-economic index showed a medium to a high score, which means high opportunities for the local community to develop their livelihood. Therefore, various community empowerment programs initiated by government, academics, the private sectors, and non-government organizations have increased the resilience of the community.

Spatial–Temporal Land Loss Modeling and Simulation in a Vulnerable Coast: A Case Study in Coastal Louisiana

Coastal areas serve as a vital interface between the land and sea or ocean and host about 40% of the world’s population, providing significant social, economic, and ecological functions. Meanwhile, the sea-level rise caused by climate change, along with coastal erosion and accretion, alters coastal landscapes profoundly, threatening coastal sustainability. For instance, the Mississippi River Delta in Louisiana is one of the most vulnerable coastal areas. It faces severe long-term land loss that has disrupted the regional ecosystem balance during the past few decades. There is an urgent need to understand the land loss mechanism in coastal Louisiana and identify areas prone to land loss in the future. This study modeled the current and predicted the future land loss and identified natural–human variables in the Louisiana Coastal Zone (LCZ) using remote sensing and machine-learning approaches. First, we analyzed the temporal and spatial land loss patterns from 2001 to 2016 in the study area. Second, logistic regression, extreme gradient boosting (XGBoost), and random forest models with 15 human and natural variables were carried out during each five-year and the fifteen-year period to delineate the short- and long-term land loss mechanisms. Finally, we simulated the land-loss probability in 2031 using the optimal model. The results indicate that land loss patterns in different parts change through time at an overall decelerating speed. The oil and gas well density and subsidence rate were the most significant land loss drivers during 2001–2016. The simulation shows that a total area of 180 km2 of land has over a 50% probability of turning to water from 2016 to 2031. This research offers valuable information for decision-makers and local communities to prepare for future land cover changes, reduce potential risks, and efficiently manage the land restoration in coastal Louisiana.

Coastal adaptation to climate change through zonation: A review of coastal change management areas (CCMAs) in England

Climate change and accelerated rates in sea-level rise are expected to increase flooding and erosion on the world's coastlines. Coastal managers and planners face the challenge of helping communities to adapt to the changing coast. Traditionally hard engineering has been used to defend communities on the coast, but as this option becomes unsustainable and financially unviable, coastal managers are increasingly employing planning policy to mitigate the risk posed by coastal change. Zonation of coastal change areas and delineation of erosion extents, such as set-back lines, are used globally to restrict development in the coastal zone. In England there is policy in place to allow planning authorities to restrict certain development in areas expected to be affected by coastal change. This study aims to examine how coastal planning authorities in England have implemented coastal change adaptation policies, specifically Coastal Change Management Areas (CCMA). These areas should include sections of coast that will experience significant change over the next 100 years through erosion, accretion or flooding. Through an analysis of planning documents, we have found that since the policy was introduced in 2012, only 15% of coastal planning authorities have designated a CCMA, with just 5.7% of the coast of England designated as a CCMA. We have found that inadequate and ambiguous guidance has reduced the effectiveness of the national policy with coastal planning authorities unsure of which datasets to apply for delineating areas of coastal change. This has led to vulnerable coastal areas being omitted from CCMAs. The datasets that are available for mapping the coastal change areas are found to vary in erosion extent and do not account for expected increases in the rate of sea-level rise. We suggest that for coastal zonation and climate change adaptation policy to be successful, a robust methodology, including a classification of coastal typologies and their response to sea level rise, is needed to delineate the extent of erosion or coastal change over the next 100 years. Understanding and mapping coastal response to sea level rise will aid planning authorities to build more resilient communities on the coast.

Impact of risk experience and personal exposure on coastal flooding and coastal erosion risk perception and coping strategies

The increasing vulnerability of coastal areas to climate change and coastal Risks, is now clearly established due to sea level rise. These events, which have become commonplace, constitute a danger for residents and for public facilities, roads, homes, etc. and make these areas more and more vulnerable. Although measures to reduce this vulnerability of coastal cities have been identified by experts and authorities, a resistance exists to their implementation by the inhabitants of these areas exposed to coastal risks. The aim of our study is to investigate risk perception and coping strategies used by inhabitants of areas at risk of coastal flooding and coastal erosion, and to identify potential differences between these two types of coastal risks. More precisely, this study seeks to identify the major predictors of the willingness to cope using Bayesian regression. 208 inhabitants of coastal areas exposed at risk of coastal flooding and erosion in Pays de la Loire, region of western France, participated to our study. Results reveal that coastal erosion is perceived as a greater threat, essentially because it is perceived as more frightening than coastal flooding. Moreover, our results showed that past experiences of coastal risks had an impact on the willingness to use active coping strategies and that there were major differences in the choice of strategy depending on the risks. These results are discussed in terms of risk management.

Development of Seawater Intrusion Vulnerability Assessment for Averaged Seasonality of Using Modified GALDIT Method

Climate change and anthropogenic activities are necessitating accurate diagnoses of seawater intrusion (SWI) to ensure the sustainable utilization of groundwater resources in coastal areas. Here, vulnerability to SWI was assessed by classifying the existing GALDIT into static parameters (groundwater occurrence (G), aquifer hydraulic conductivity (A), and distance from shore (D)) and dynamic parameters (height to groundwater-level above sea-level (L), impact of existing status of seawater intrusion (I), and aquifer thickness (T)). When assessing the vulnerability of SWI based on observational data (2010–2019), 10-year-averaged data of each month is used for GALDIT dynamic parameter for representing the seasonal characteristics of local water cycles. In addition, the parameter L is indicated by the data observed at the sea-level station adjacent to the groundwater level station. The existing GALDIT method has a range of scores that can be divided into quartiles to express the observed values. To sensitively reflect monthly changes in values, the range of scores is divided into deciles. The calculated GALDIT index showed that the most vulnerable month is September, due to relatively low groundwater level. The proposed method can be used to apply countermeasures to vulnerable coastal areas and build water resources management plan considering vulnerable seasons.

Vulnerability Assessment for Sea Level Rise Impacts on Coastal Systems of Gamasa Ras El Bar Area, Nile Delta, Egypt

The objective of the current study was to assess the vulnerability of coastal systems to sea level rise (SLR) impacts in the Gamasa Ras El Bar area, which is one of the most vulnerable coastal areas in the Nile delta, Egypt. To achieve the study objective, a field campaign was carried out to investigate, measure and collect data. These data, as well as historical data, were analyzed to identify projected inundation areas, erosion and accretion rates, shoreline changes, wave climate and saltwater intrusion, as well as drainage infrastructure efficiency. The results of a 73-cm SLR, projected up to the end of current century in the study area, indicate the following. Inundation areas will be about 2.16% of the study area. Although the significant wave height increased by 3.1 cm per year from 1999 to 2010, the results are indicative and might be taken into consideration in future coastal management plans. The expected variation in groundwater heads due to sea level rise will lead to an increase in groundwater heads ranging from 0 to 0.5 m above the current level. The change expected in groundwater will lead to saltwater intrusion by 1 km landward. The analysis of our results showed that about 271 km2 (60%) of the area under study will be negatively affected by rising groundwater. This area is occupied by about 70% of the localities in the study area. The analysis of the projected groundwater level rise showed that it will increase the discharges of the sub-drainage system by about 10% of the current rates and less than 1.2% for the open system. It is concluded that the drainage system has the sub-capacity to host the expected increase in drainage discharges without any modifications of the cross-sectional area of most of the drains. In addition, the coastal groundwater aquifer was found to be the most vulnerable system in the study area.