The evaluating coastal zone Physical vulnerability, Sefidrood River Delta

This study aims to characterize the physical vulnerability of the western coast of Santa Catarina Island by applying the Smartline methodology. Erosion and flooding processes can endanger the installed human infrastructure in the coastal zone, with the degree of vulnerability of a given site being dependent on its natural characteristics, or even due to changes induced by human action. The methodology applied in this research adopts a multiscale approach and considers, using coastline segmentation, the specificities of the analyzed coastal sectors. Each identified segment receives a classification regarding its physical vulnerability, resulting from the integration of several attributes, which must be selected according to the coastal hazard that one wishes to represent. In the analysis, three distinct levels of physical support and behavior of the coastal processes are considered. The first-order attributes are structural, and their characteristics are broad; the second-order ones are transitional between structural and dynamic and, the third-order attributes are dynamic, with specific characteristics. The methodology was applied on the west coast of Santa Catarina Island, a sector sheltered from oceanic waves, characterizing a low energy environment. Eight descriptors were selected for erosion and coastal flooding, these being: “geology” having two classes, distributed along 12 segments and “geomorphology”, three classes in eight segments, both of which were considered first-order variables. “Average astronomical tide current speed” (five classes in 15 segments), “average backshore height” (four classes in 20 segments), and “degree of exposure to wind waves” (five classes in 28 segments) compose the second order, while “backshore features” (seven classes in 28 segments), “grain size” (five classes in 26 segments) and “beach face slope” (three classes in 30 segments) describe third-order processes. By the integration of first-order attributes an Indicative Map of Vulnerability to Erosion and Flooding was generated, which classified the coast into “very Low”, “low”, “moderate”, and “high” vulnerability classes. As a final result of the analytical process the coastline, first-, second-, and third-order attributes were mathematically integrated by means of spatial analysis techniques, with the studied coastline represented as a segmented line according to the different classes of attributed physical vulnerability, highlighting the sectors with the most propensity to erosion and flooding. This Map of Physical Vulnerability to Erosion and Flood indicated that the west coast of Santa Catarina Island can be divided into sectors of low and moderate vulnerability in similar proportions, with occasional occurrences of high vulnerability in specific sectors.

Coastal erosion vulnerability assessment along the eastern coast of Bangladesh using geospatial techniques

The shoreline of Kalutara, Sri Lanka has become more prone to erosion because of environmental changes caused by natural and anthropogenic factors including climate change. The study aimed to assess and map the physical and social vulnerability to coastal erosion in the shoreline between the Kalu and Bolgoda River mouths in Southwest Sri Lanka. This study relied on secondary data sources such as topographic, digitized, and satellite maps obtained from the Survey Department and the website of the United States Geological Survey (USGS). The Coastal Vulnerability Index (CVI) was calculated using only five variables namely coastal slope, geology, soil, shoreline change (End Point Rate), and Land Use and Land Cover (LULC). On the other hand, for the Social Coastal Vulnerable Index (SVI), several socioeconomic variables were examined. Kalutara North and Thotupala have been identified as having a higher risk of Physical and Social Coastal Vulnerability. This research, therefore, revealed that the coastal zone along Kalutara – Panadura in Sri Lanka is vulnerable both physically and socially due to the accelerating rate of coastal erosion. Because of the potential effects of climate change and rising sea levels, this scenario would pose a serious threat to the environment and communities in the foreseeable future.

Abstract. Assessing coastal vulnerability to climate change at regional scales is now mandatory in France since the adoption of recent laws to support adaptation to climate change. However, there is presently no commonly recognised method to assess accurately how sea level rise will modify coastal processes in the coming decades. Therefore, many assessments of the physical component of coastal vulnerability are presently based on a combined use of data (e.g. digital elevation models, historical shoreline and coastal geomorphology datasets), simple models and expert opinion. In this study, we assess the applicability and usefulness of a multi-criteria decision-mapping method (the analytical hierarchy process, AHP) to map physical coastal vulnerability to erosion and flooding in a structured way. We apply the method in two regions of France: the coastal zones of Languedoc-Roussillon (north-western Mediterranean, France) and the island of La Réunion (south-western Indian Ocean), notably using the regional geological maps. As expected, the results show not only the greater vulnerability of sand spits, estuaries and low-lying areas near to coastal lagoons in both regions, but also that of a thin strip of erodible cliffs exposed to waves in La Réunion. Despite gaps in knowledge and data, the method is found to provide a flexible and transportable framework to represent and aggregate existing knowledge and to support long-term coastal zone planning through the integration of such studies into existing adaptation schemes.

Coasts are highly dynamic and geo-morphologically complex systems that are exposed to several factors such as waves, extreme meteorological events and climate change. It is also well-recognized that coastal zones, characterized by an increasing population growth, are vulnerable to climate change. In addition, coastal erosion, resulting from natural environment changes and human activities, acts worldwide. Consequently, it is necessary to quantify coastal hazards vulnerability and develop tools to monitor coastal risks and support making targeted climate adaptation policies. In this paper, a framework to estimate coastal vulnerability to flooding and erosion has been developed for the Ionian Basilicata coast. It is based on two methods: the integrated vulnerability index (flooding and erosion) and the CeD physical vulnerability index (multi-risk assessment). Our results are in agreement with the recent shoreline evolution: the integrated coastal risk of the Ionian Basilicata coast is generally medium to high, while the “physical erosion vulnerability” is generally high to very high. In addition, the results highlight a spatial variability of the vulnerability, probably due to the morphology of the beach, which requires developing a strategic approach to coastal management and defining mitigation measures, considering relevant risk aspects as the vulnerability and exposure degree.

Increasing risks from sea-level rise and other climate impacts call for a focus on physical coastal attributes, emphasising the need for region-specific tools to address the vulnerability of different coastlines. This paper presents the development of a Physical Coastal Vulnerability Index (PCVI) for climate change impacts like sea-level rise, erosion, and storm surges, which is applied to the Croatian coast of the Istrian Peninsula. The methodology provides a detailed, site-specific vulnerability assessment focusing on physical parameters such as coastal aspect, slope, elevation, and coastal type. Eight different grid cell sizes were evaluated to map the coastline, demonstrating, as expected, that smaller cells (5 × 5 m) captured more detailed variability in vulnerability. Among seven evaluated calculation methods, the second root of the self-weighted arithmetic mean (M3) proved the most effective, emphasising high-risk regions by prioritising critical physical variables. The results show that the western Istrian coast is more vulnerable due to its morphological properties, with nearly 50% of highly vulnerable coastlines. This paper emphasises the importance of using high-resolution grids to avoid oversimplification of vulnerability assessment and recommends using PCVI as a basis for further socio-economic assessments. The proposed PCVI methodology offers a framework that can be adapted to assess the physical vulnerability of the eastern Adriatic coast and other similar coastal regions, particularly in the Mediterranean, enhancing its relevance for integrated coastal zone management and global climate change mitigation strategies.

This study aimed to evaluate the landslide risk map in the Algerian Western coasts. This evaluation was based on three steps. The first step requires evaluating the landslide hazard. To reach this, a field surveys data, combined with Geographical Information System (GIS) analysis and Remote Sensing (RS) image processing were carried out. Seven controlling factors were considered: lithology, geomorphology, slope, land use, distance to stream, rainfall and distance to fault. A topographic map of 1/ 25 000 was used to generate a Digital Elevation Model (DEM) with 15 × 15 m of resolution. From this DEM, the slope was extracted. Based on knowledge approach, the different factors were weighted according a scale value ranging from 1 to 9. The lowest values were assigned to the factors which have a minor influence on landslide triggering, and the highest values were given to the important parameters for landslide occurrence. These factors were combined using weighted linear combination (WLC). The landslide hazard map was classified into five levels: very low, low, moderate, high and very high. The landslide vulnerability was evaluated through the identification of the elements at risk. Three vulnerabilities aspects were considered: physical, environmental and socio-economic. The weights of each factor were given depending on the magnitude and the rate of landslide. Landslide Vulnerability Map (LVM) for Algerian western coasts was generated by the combination of the physical, environment and socio-economic vulnerability maps. Landslide risk was evaluated by combining the hazard map and the vulnerability map, and it was divided into four classes: very low, low, moderate and high.

Hurricane Maria, a category 4 tropical cyclone, hit the US non-incorporated territory of Puerto Rico on September 20, 2017. Widespread physical and natural infrastructure damage was observed, especially in already vulnerable coastal communities. As public sector funding availability for natural infrastructure (ex. coastal ecosystems) increases, mechanisms for its efficient and equitable allocation are lacking. An accessible and replicable coastal vulnerability indicator framework is presented to assist state and federal policy makers in the allocation of funding for coastal natural infrastructure recovery. To assess funding priorization gaps and test the applicability of the proposed framework, spatial patterns in the estimated funding need identified in state-led post-Hurricane Maria assessments for natural infrastructure rehabilitation efforts were compared to physical and social coastal vulnerability estimations. Three main challenges that emerge during the implementation of a vulnerability indicator framework were considered for its design: (1) the compressed time frame in which decisions are made after an extreme weather event, (2) the availability of data to calculate indicators in a reduced time frame, and (3) the accessibility of results to a broad variety of stakeholders. We propose a vulnerability indicator framework that can become operational in a relatively short period of time, attempts to simplify data gathering efforts, and uses methods that aim to be more transparent and understandable to a broad group of stakeholders.

Tropical cyclone (TC) landfalls are among the most damaging natural disasters. The North Indian Ocean (NIO) experiences ~12% of all cyclones every year. TC damage is primarily due to high wind gusts, rainfall, storm surges, waves and coastal flooding which pose serious risks to life, property and coastal ecosystems. Extreme wave activities, vegetation loss due to gale winds and saltwater intrusion during coastal inundation cause coastal erosion and turn agricultural land infertile over extended periods of time. The rate of TC devastation also depends on coastal Land Use and Land Cover (LULC: vegetation density, barren lands, agricultural fields, etc.). TCs in turn change the LULC and soil characteristics, thus modulating the land surface properties. The extent of physical and social vulnerability due to TCs are directly associated with population density, coastal infrastructure and TC frequency and intensity. Improved forecast and advanced preparedness are crucial to reduction in TC related fatalities with early risk assessment being key to disaster mitigation. The coastal vulnerability and impact of land-falling TCs in the NIO were analyzed. Assessment frameworks, observational tools and mitigation strategies were reviewed and critical factors for better disaster preparedness and mitigation of TC impacts in the coastal regions were identified.KeywordsTropical cyclonesCoastal vulnerabilityHazard assessmentNorth Indian OceanDisaster mitigationRemote sensing

An oil risk management system based on high-resolution hazard and vulnerability calculations

Continued population growth and development in exposed areas across Coastal Louisiana has created a new geography of hazards and disasters within the coastal zone. Increasing storm frequencies coupled with sea level rise will undoubtedly intensify the intersection between flood hazards and coastal residents. Accordingly, the baseline (inherent) capacity of places to adequately prepare for and rebound from disaster events will be negatively impacted. This paper summarizes the value of incorporating research‐based techniques into a non‐structural assessment of flood vulnerability within the Northshore Region of Louisiana. The exploratory nature of the methodology employed in this study was focused on determining the value of non‐structural measures of vulnerability in mitigation planning and the role of research in evidence‐based decision support for public officials. The outcome of the study highlighted new perspectives for measuring vulnerability within a policy environment, offering community officials a more robust understanding of the dynamic intersection of the physical threats, social vulnerability, and economic components of flood risk. This knowledge is currently being used by decision makers in the region to cultivate enhanced mitigation tactics that have traditionally been structurally focused. By incorporating the biophysical, economic, and social vulnerability into a qualitative “place” vulnerability matrix for the study area, the authors have been able to gain a more robust understanding of the flood risks across the region. By integrating this new understanding of risk into potential mitigation strategies, planning for risk reduction expenditures can more appropriately consider the drivers of place‐specific vulnerability.

In the present research work, an attempt has been made to assess the coastal vulnerability of the Konkan stretch between Bankot and Dabhol creeks, Maharashtra, using GIS and various sources of geospatial data. The study area comprises the coast of Mandangad and Dapoli tahsils in the northern part of Ratnagiri district. The study area is bounded by two west flowing rivers debouching into the Arabian Sea viz.: Savitri River in the north and Vashishti River in the south. The study area is a part of Western Ghats and coastal plains agroecological region. The tropical cyclones in the Arabian Sea in recent years have stressed the importance of assessing the vulnerability of coastal areas to flooding and inundation. The coastline of Ratnagiri district, which has many beaches, tourism places, fishing villages, ports and towns, has been facing risk from cyclones, floods and erosion. The major objective of the present work is analysis and integration of physical variables with socio-economic variables to assess the coastal vulnerability. The physical coastal vulnerability index (PCVI) parameters are coastal geomorphology, shoreline changes, coastal slope, sea level rise rate, significant wave height and tidal range. The socio-economic coastal vulnerability index (SCVI) parameters are population density, coastal land use, coastal roads and economic activities. A composite coastal vulnerability index (CCVI) based on physical and socio-economic parameters has been calculated for every coastal segment, which reveals the overall coastal vulnerability. A coastal zone management action plan has been prepared to mark the coastal segments requiring higher priority for coastal protection viz.: Harnai-Paj Pandhari beach (No Development Zone under CRZ-IIIA), Murud village, Dabhol (Vashishti River mouth), etc. Ecologically sensitive areas viz. turtle nesting grounds, mangrove swamps, etc. have also been analyzed. The coastal vulnerability map is useful in decision-making for disaster management and integrated coastal zone management. Keywords: Erosion; PCVI; SCVI; CCVI; GIS

The study area (the Gulf of Bejaia) is a coastal zone of about 70 km long in the eastern-central part of the Algerian coast. The coastline characterized by sandy beaches, hotels and tourist facilities, airport, port, villages and towns has known during these last decades several threats like storms, floods and erosion. The present work concerns the mapping of the physical and socioeconomic vulnerability of the Gulf Coast of Bejaia to sea level rise, using Coastal Vulnerability Index (CVI) and geospatial tools. The Physical CVI (CVIPhys) is calculated from seven physical variables: geomorphology, coastal slope, coastal regional elevation, sea level rise rate, shoreline erosion/accretion rates, tidal range and significant wave height. On the other hand, the parameters population, cultural heritage, roads, railways, land use and conservation designation constitute, for their part, the socioeconomic CVI (CVIeco). The values obtained from the calculation of CVIPhys vary between 3.53 and 81.83. These results revealed that 22.42 km of the studied coastline has a low physical vulnerability, 21.68 km a high vulnerability and 15.83 km a very high vulnerability, indicating that the most part of the coastline (53.59%) is vulnerable to sea level rise. According to the obtained values of CVIeco, the most vulnerable areas of high and very high risk represent 31.81 km of the total coastline. They were found along the western (Bejaia and Tichy) and eastern (Aokas, Souk El Tenine and Melbou) coast, while the least vulnerable stretches, covering 38.19 km of the total length of the coast, occupy the rest of the area. This study highlighted areas that will be most affected by future sea level rise (SLR) and storm events. It revealed that several development projects of Bejaia Gulf Coast, including tourist expansion areas, are planned in sites identified as very vulnerable. The results obtained from this assessment could guide local planners and decision-makers in developing coastal management plans in the most vulnerable areas.

Coastal vulnerability assessment to multi hazards in the exposed coast of Southeastern Coastal Region of Bangladesh

Coastal areas face increasing threats from extreme weather and rising sea levels, exposing both human populations and delicate ecosystems. This study evaluates the physical vulnerability in the Santa Elena Bay (SEB) coastline, which is setting in the active margin of Ecuador, which is highly influenced by geological vertical movements. The results of this study permit us to give some recommendations to coastal management. Employing the Coastal Vulnerability Index (CVI), we analyze variables such as lithology, geomorphology, beach slope, coastal indentation, shoreline displacement, and wave height. The CVI categorized the coast into four vulnerability ranks: Low, Moderate, High, and Very High. Results indicate that low-lying beaches, especially in the Northern zone, where there are higher waves, are the most vulnerable. The Northern zone of SEB exhibits substantially higher vulnerability, with 15.80% of the coast classified as High and 41.76% as Very High. Key factors contributing to Very High vulnerability include low indentation (63.96%), high wave heights (58.69%), and quaternary sediments (57.41%). Conversely, the Southern zone primarily demonstrates High and Low vulnerability, however critical areas can be found which have some important infrastructure to tourism, i.e. Monteverde, San Pablo, Punta Barandúa, Ballenita, and Salinas. The findings highlight the urgency of implementing mitigation measures and integrating adaptive management strategies into urban development policies to reduce the vulnerability of coastal communities and protect local ecosystems.