Coastal Erosion Vulnerability Research Articles

Derivation of Coastal Erosion Susceptibility and Socio-Economic Vulnerability Models for Sustainable Coastal Management in Senegal

Coastal erosion has posed significant challenges to sustainability and socio-economic stability along Senegal’s coastline, leading to substantial infrastructure losses. Using GIS multi-criteria decision analysis (MCDA), two sub-indices were derived for Senegal’s coastal departments: the physical susceptibility (PSI) and the social-economic vulnerability (SVI) to coastal erosion. The integrated coastal erosion vulnerability (ICER) model was derived by their aggregation. A total of 26 criteria were used, 18 for PSI and 8 for SVI. The criteria weighting coefficients of the sub-indices were determined using the analytic hierarchy process (AHP). Validation of the model accuracy was performed using receiver operating characteristic (ROC) curves that were calculated based on a created coastal erosion cadaster and true positive (TP) sites and manually acquired true negative (TN) sites. The accuracy assessment confirmed the consistency of the physical susceptibility model (PSI) and proved that existing coastal erosion sites are within (5) very high susceptibility areas. Through the generated ICER, the coastal departments were divided into areas of (1) very low, (2) low, (3) medium, (4) high and (5) very high vulnerability to coastal erosion. Very high (5) and high (4) classes cover around 31% of the coastal departments, mostly encompassing a narrow coastal strip and low river valleys and mouths. The presented coastal susceptibility and vulnerability maps, with a spatial resolution of 30 m, identified problematic areas in Senegal’s coastal departments and can help decision-makers in the construction of effective coastal zone management and sustainable development.

GIS-Based Analytical Hierarchy Process Modelling and Mapping of Erosion Vulnerability in the Coastal Areas of Rivers State, Nigeria

The problem of coastal erosion in rivers State Nigeria is a significant issue that has far-reaching consequences for the environment and local communities. Despite the efforts of previous research there remains a lack of comprehensive understanding of the factors contributing to erosion vulnerability and their relative importance, hindering effective decision-making and management practices aimed at mitigating the effects of coastal erosion in Rivers State. Therefore, this study aimed at a GIS-based analytical hierarchy process modeling and mapping of coastal erosion vulnerability in Rivers State, Nigeria. The objectives are to establish and classify the geophysical factors according to the levels of coastal erosion risk, calculate the reliability index of the classified geophysical factors, determine the coastal vulnerable areas across Rivers State using analytical hierarchical process and to produce a coastal vulnerability index map defining the extent of erosion vulnerability in Rivers State. The methodology comprises of the acquisition of primary and secondary data, image pre-processing, image classification, DEM processing, classification and standardization of factors, development of pairwise comparism, and weighted linear combination analysis. The study revealed three distinct coastal erosion vulnerability zones: high, moderate, and low vulnerability. The high vulnerability zone encompassed a total expanse of 545.29 square kilometers, constituting 6.38% of the study area. In contrast, the moderate and low vulnerability zones covered 1941.33 square kilometers and 6052.51 square kilometers, respectively, making up 22.73% and 70.89% of the total area. Bonny (139.28 sq km) was ranked as the most vulnerable due to its role as an oil and gas hub. Degema (111.28 sq km) ranked second and requires urgent erosion control. Okrika and Andoni (71.73 sq km and 62.20 sq km) were third and fourth respectively. It is recommended that an advocate for the systematic approach to coastal vulnerability zoning be introduced in the study. The categorization of areas into high, moderate, and low vulnerability zones provides a standardized framework for assessing coastal regions' susceptibility to erosion. This approach can be applied to other regions to facilitate consistent vulnerability assessments.

Preparing coastal erosion vulnerability index applying deep learning techniques in Odisha state of India

With the changing climatic and anthropogenic conditions, the natural ecosystem especially the coastal zones is at great risk. The ocean is engulfing the land through the process of coastal erosion and this is becoming a great threat to coastal communities by forcing them to relocate from their homes and destroying their livelihoods. This study has tried to use machine learning algorithms for the first time to find the probability of the vulnerability associated with this hazard along the coast of Odisha state of India using a total of 32 factors involving environmental and socio-economic conditions. A total of 2500 locations have been used to create support vector machine (SVM), random forest (RF), shallow neural network (SNN), deep neural network (DNN), and convolutional neural network (CNN) models. Various accuracy metrics have been calculated which showed the RF model outperformed all with an accuracy score of 0.96. This is followed by CNN (0.93), DNN (0.91), SVM (0.88), and SNN (0.88). Further, to find the impact of all the factors in the model sensitivity analysis has been performed. Factor importance analysis by RF has been performed at state and district levels to understand the influence of various parameters in this disaster. This novel method will broaden the approach which we use to analyze this calamity and serve as an aid in the decision-making process of the concerned authorities.

An Approach for the Validation of a Coastal Erosion Vulnerability Index: An Application in Sicily

In recent decades, coastal erosion phenomena have increased due to climate change. The increased frequency and intensity of extreme events and the poor sediment supply by anthropized river basins (dams, river weirs, culverts, etc.) have a crucial role in coastal erosion. Therefore, an integrated analysis of coastal erosion is crucial to produce detailed and accurate coastal erosion vulnerability information to support mitigation strategies. This research aimed to assess the erosion vulnerability of the Sicilian coast, also including a validation procedure of the obtained scenario. The coastal vulnerability was computed by means of the CeVI (Coastal Erosion Vulnerability Index) approach, which considers physical indicators such as geomorphology and geology, coastal slope, sea storms, wave maxima energy flux and sediment supply to river mouths. Each indicator was quantified using indexes which were assessed considering transects orthogonal to the coastline in 2020. These transects were clustered inside natural compartments called littoral cells. Each cell was assumed to contain a complete cycle of sedimentation and not to have sediment exchange with the near cells. Physical parameters were identified to define a new erosion vulnerability index for the Sicilian coast. By using physical indexes (geological/geomorphological, erosion/sediment supply, sea storms, etc.), the CeVI was calculated both for each littoral cell and for the transects that fall into retreating/advancing coastal areas. The vulnerability index was then validated by comparing CeVI values and the coastline change over time. The validation study showed a direct link between the coastline retreat and high values of CeVI. The proposed method allowed for a detailed mapping of the Sicilian coastal vulnerability, and it will be useful for coastal erosion risk management purposes.

Characteristics and evaluation of coastal erosion vulnerability of typical coast on Hainan Island

Coastal erosion vulnerability assessment is widely used to assess the loss degree of coastal zone caused by erosion, and plays an important role in coastal natural resources protection, planning, management and decision-making. Based on the natural and social characteristics of the east coast of Qiongdong and the coastal erosion vulnerability index (CVI) method, this study selected 8 assessment indicators, such as shoreline change rate (U1). The Delphi method and the entropy weight method were used to calculate the comprehensive index weight, combined with CVI method and geographic information system (GIS) technology, to quantitatively evaluate the temporal and spatial distribution characteristics of typical coastal erosion vulnerability such as coral reefs in the east of Hainan Island. The study area was divided into 5 grades: very low (31%), low (10%), moderate (28%), high (24%) and high vulnerability (7%), and the overall performance was moderate erosion vulnerability. The research showed that the interannual downward rate erosion of beach (U3) and the rate of change of the isobath (U2) of the beach were the main controlling factors affecting the vulnerability of coastal erosion in the study area, and the coastal dynamic factor had a greater impact than the other two factors. As a natural barrier, the coral reefs in the study area had good wave absorption and energy reduction, and the coral reef coasts showed low coastal erosion vulnerability, due to the complex hydrodynamic characteristics, estuary coasts is the most vulnerable areas. The verification results of the ROC-AUC method showed that the accuracy of erosion vulnerability was 68.9%, which provided an important reference for the ecological restoration of tropical coral reef biological coasts and the development and management of the Hainan Qiongdong coastal zone.

Rapid migration of mainland China's coastal erosion vulnerability due to anthropogenic changes

With the global rise in sea levels caused by climate change and frequent extreme weather processes, high-density population aggregation and human development activities to enhance coastal areas vulnerability, populations, resources, and the ecological environment are facing huge pressure. Natural coastlines are being destroyed, and increasingly serious problems, such as coastal erosion and ecological fragility, have become disasters in coastal zones. The coastal vulnerability changed by climatic variables has created a major concern at regional, national and global scales. By comparing the data of two periods in the past 40 years, coastline vulnerability of coastal erosion in mainland China were evaluated by use of reverse cloud model and AHP with 10 indicators, including natural, anthropogenic, social and economic factors, etc. The main factors controlling coastal erosion included the proportion of Quaternary strata, the gradual reclamation of marine areas as land areas (in kilometres) and the percentage decrease in coastal sediment entering the sea. The secondary impact factors included the high proportion of artificial coastlines and the impacts of waves and storm surges under the influence of relative sea level changes. Human activities could further influence coastal vulnerability, making the erosion risk a considerable concern. Legislation, coordinated management system and technology are proposed to improve the quality of the marine ecological environment.

Coastal Vulnerability Assessment for Community Resilience on Abrasion: Case of Bugel Coast, Kulon Progo Regency, Indonesia

The coastal boundary can be optimized for settlement and agriculture site based on a spatial plan for Kulon Progo Regency 2012–2032 within a minimum distance of 100m from the coastline. The location of ring 1 local transmigration settlement on the Bugel Coast is less than 100 m. The increasing trend in coastal erosion caused by climate change is a major contributing factor to the reduction of coastal borders. Thus, rapid assessment of coastal erosion vulnerability is necessary to determine an effective coastal management response. This paper aims to analyze the coastal erosion level using vulnerability assessment, geomorphology of coastal areas, and community resilience impact. The methods used in the mapping of coastal segments are smartline and coastal vulnerability index (CVI). The Smartline method is depicted with a line that runs along the coast with information on geomorphological conditions, whereas the CVI method will give weight to each physical parameter of coastal erosion vulnerability. Results showed that the average area of Bugel Coast decreased by 4,794.94 m2 /year and retreated by 4.36 m/year until the borders become closer to one another, thereby threatening the settlement area. The coastal erosion vulnerability was dominated by a moderate level of 325.14 m (30.48%) to a high level of 322.31 m (30.22%) of the total study areas. This result indicated the huge risk of coastal erosion. Therefore, effective community adaptation and mitigation strategies should be considered to reduce the degradation of coastal border resources and ensure the sustainability of local life, such as the combination of structural and non-structural mitigations that prioritize the sustainability of coastal ecosystems.

Vulnerability Evolution of Coastal Erosion in the Pearl River Estuary Great Bay Area Due to the Influence of Human Activities in the Past Forty Years

Under the dual effects of global climate change and intensive human development activities, vulnerability to coastal erosion in bay areas is becoming increasingly serious. This study focuses on 15 counties and districts along the coast of the Pearl River Estuary (PRE) Great Bay Area and selects 12 evaluation indices from five perspectives for analysis, including coastal characteristics, hydrodynamic forces, economics, population and coastal reconstruction. The analytic hierarchy process (AHP) method, Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) method, independent weight method, Jenks natural breaks method (Jenks), exposure-sensitivity-adaptation (ESA) model and obstacle degree method are used in conjunction with the above indices to construct a coastal erosion vulnerability evaluation system for the PRE. The results show that coastal erosion vulnerability in the PRE is low in the eastern hilly area and high in the central and western delta areas. Coastal characteristics, coastal lowlands and protection capability are the main controlling elements of erosion. The PRE experienced an era of rapid economic development from 1980 to 2010, and coastal erosion vulnerability gradually increased, with a cost of ecological environment destruction. Then, an era of coastal zone ecological restoration supported by policy protection occurred from 2010 to 2020. Compared with three major bay areas with similar developed economies worldwide, the PRE is characterized by comparatively late but rapid economic development. Notably, the development and utilization efficiency of coastal zones is very high, the duration of damage to the ecological environment is short, and the effects of ecological repair and restoration are obvious. The results of this study provide a reference for economic development and ecological restoration in the bay areas of China and provide scientific guidance for coastal zone development, management and planning.

Coastal Erosion Vulnerability in Mainland China Based on Fuzzy Evaluation of Cloud Models

Global climate change-induced sea-level rise and storm wave intensification, along with the large population densities and high-intensity human development activities in coastal areas, have caused serious burden and damage to China’s coasts, led to the rapid growth of artificial shorelines development, and formed a “new Great Wall” of reinforced concrete against the laws of nature. After the last ice age, transgression formed the different features of China’s coast. Depending on the types of geological and landform features, coasts are divided into 36 evaluation units, and 10 indicators are selected from natural aspects (including tectonics, geomorphology, sediment, and storms) and aspects of social economy (population, GDP, Gross Domestic Product), and cloud model theory is used to build a coastal erosion vulnerability evaluation index system in China. The results show that high grade (V), high-middle grade (IV), middle grade (III), low-middle grade (II), and low grade (I) coastal erosion vulnerability degrees account for 5.56, 13.89, 41.67, 33.33, and 5.56% of the Chinese coastlines, respectively. The coastal erosion vulnerability of the subsidence zone is significantly higher than that of the uplift zone. Reverse cloud model and analytic hierarchy process calculation show that the main factors that control coastal erosion vulnerability since the transgression after the last ice age are geological structure, topography and lithological features, and in recent years, the decrease in sea sediment loads and increase in reclamation engineering. Mainland China must live with the basic situation of coastal erosion, and this study shows that the index system and method of cloud modeling are suitable for the evaluation of the coastal erosion vulnerability of the Chinese mainland. This study provides a scientific basis for the adaptive management of coastal erosion, coastal disaster assessment and the overall planning of land and sea.

Flaws in coastal erosion vulnerability assessment: Physical and geomorphological parameters

Flaws in coastal erosion vulnerability assessment: Physical and geomorphological parameters

Are Current UK Coastal Defences Good Enough for Tomorrow? An Assessment of Vulnerability to Coastal Erosion

Coastal vulnerability and its physical, economic and social consequences at national and international scales is of high scientific, political and policy interest. Anthropogenic climate change and coastal erosion threaten the very fabric of a society. Indications, that coastal hazards are impacting diverse coastal areas severely across the world, and it is no longer a vague future threat that can’t be ignored. Rising eustatic sea levels synthesized by the growing frequency and scale of coastal hazards like storm surges, coastal erosion and coastal landslides threaten low-lying and unprotected coastal areas in the United Kingdom even if they have coastal defenses. However, there is still significant uncertainty about the degree of vulnerability along different coastal stretches, particularly in England. To fill this uncertainty, the current study estimated the coastal vulnerability of the coastal erosion hotspot Camber, England, by establishing a coastal vulnerability index. This index was developed by compounding various existing parameters and termed as Erosion Coastal Vulnerability Index (ECVI). Results illustrate that 67% of coastal area fall between high and very high vulnerability categories, and current coastal defenses are not strong enough to tackle the severe coastal erosion in Camber. Within the evaluation, thematic maps were generated to enable the intensity of the vulnerability for different coastal stretches to be identified. The evaluated vulnerable hotspot should be treated urgently by regional and national policy organizations to ameliorate the impacts of coastal erosion and other associated risks. Without action, the hotspot is likely to encounter unprecedented new vulnerabilities, disasters and humanitarian catastrophes. The current study results allow for a local, regional and national comparison that may help to evaluate changes in coastal erosion vulnerability.

Assessment of coastal erosion vulnerability and socio-economic impact along the Yangtze River Delta

Vulnerability assessment is critical for management of hazards in coastal area. However, research on erosion vulnerability assessment in delta region is still very limited. In this paper, we assessed the erosion vulnerability of 49 towns along the coast of the Yangtze River Delta by combining five physical (i.e., mean tidal range, mean wave height, suspended sediment concentration, tidal flat width, and coastal slope) and three social (i.e., embankment height, GDP per unit area, and fiscal revenue) indicators using the percentile ranking method. Population density and land use were analyzed to reveal the potential socio-economic impact of erosion. The assessment result of physical vulnerability is validated by comparison with the bathymetric change between 1980s and 2010s and previous assessment studies using different indicators and aggregation methods. Our results show that areas categorized as very high, high, moderate, low, and very low vulnerability account for 13%, 22%, 39%, 24% and 2% of the coastal towns, respectively. Vulnerable towns with very high and high socio-economic impacts are located along the coastline with narrow tidal flat and lower social coping capacities. The large variability in the physical vulnerability assessment result demonstrates that fine scale study at town level is extreme important, considering the spatial heterogeneity in geomorphological process within the fluival-tidal delta. Our method of erosion vulnerability assessment has potential use in deltaic environments elsewhere.

Understanding the coastal erosion vulnerability influence over sea turtle (Eretmochelys imbricata) nesting in NE of Brazil

Most of the studies on sea turtle nesting activity nowadays are focused on the impacts of climate change. However, there is a lack of studies gathering knowledge about the influence of coastal vulnerability to erosion and settlement to assess sea turtle nesting. This study aims to verify the influence of coastal erosion vulnerability over sea turtle nesting in five Brazilian Northeast beaches, in Pernambuco state, at Ipojuca coast. The main analyzed parameters were the urban settlement, coastal erosion indicators and the conservation status of the dunes by assessing shoreline change rates, backshore extension, vegetation cover and beaches morphodynamics associated aspects. Spearman’s rank correlation coefficient and tests of Kruskal–Wallis, Mann–Whitney, Shapiro–Wilk and Levene were employed as a set of statistical analyses. The results state that Eretmochelys imbricata is the predominant species that nests at the Ipojuca coast (93.2% of nesting females). There is a significant difference in the number of nests among the studied beaches (Kruskal–Wallis; p = 0.004). A strong and positive correlation between the backshore width and the number of nests was verified (Spearman’s rank correlation, rs = 0.881; p = 0.0002). The results indicate the preference for nesting on wave-dominated beaches, where the coastal reefs are absent and there is a well-developed backshore, mainly due to the lower urban settlement in these areas. Thus, efforts focused on preserving nesting beaches, especially those under high urbanization, are a key factor for sea turtle preservation.

Coastal resilience potential as an indicator of social and morphological vulnerability to beach management

Indicator-oriented approaches embrace several aspects of coastal erosion vulnerability assessments. Nonetheless, coastal erosion is mostly increasing because of both the lack of univocal and resolutive practices on coastal management and increasing human pressure on coastal systems. This article proposes the implementation of an Index of Social and Morphological Vulnerability (ISMV) to show how the cost of services and morphological trends can affect the distribution of benefits, produce coastal narrowing, and consequently the resilience potential of coasts. This innovative indicator framework was carried out for the Mediterranean area of San Vincenzo in Italy. The analysis highlights that administrative actions can be crucial to support or to impoverish the resilience potential. Areas of relative regeneration capacity were distinguished as high (4.11), moderate (0.37), and low (0.33). They could be enhanced just by planning resolutive beach management at a local scale. In this context, some resolutive actions are proposed in the framework of an aggregate multi-index approach that connect with the main Intervention Concerning the Erosion Causes (ICEC) strategies. The results obtained support the definition of the ISMV as an adequate policy tool to implement modifications in the maritime domain concession system aimed at sustainability and social justice.

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

Coastal zones are physically, socially, and economically important. However, many coastal zones are highly vulnerable to coastal erosion due to high population density, tourist attractions, developed economy, and lowland. Erosion vulnerability assessment with limited criteria and components cannot provide detailed and accurate results. Therefore, an integrated vulnerability assessment of coastal erosion is essential to produce detailed and accurate erosion vulnerability information to support mitigation strategies. This study aims to prepare an integrated coastal erosion vulnerability approach using geospatial techniques and examine the pattern of vulnerability to coastal erosion effects in the eastern coastal region of Bangladesh. Thirteen spatial criteria under two components of vulnerability, namely, physical and socio-economic vulnerability, were assessed. These criteria were weighted on the basis of the analytical hierarchy process (AHP) and then combined to generate individual vulnerability indices. Finally, the overall vulnerability map was produced by integrating physical and social vulnerability indices. Results showed that the area of very high vulnerability includes 11% of the region, and the area of high vulnerability was 24%. Parts of Chittagong Port, Cox's Bazar, Kutubdia, Teknaf, Ukhia, Anowara, and some portions of Moheshkhali regions close to the coastline of the study site are likely to experience high vulnerability of coastal erosion impacts. The area was classified as a low- and very-low-vulnerability zone, representing 27% and 8%, respectively. For evaluating the efficiency of the outcome, the receiver operating characteristics (ROC) technique was used to validate the physical erosion vulnerability results, which stated an 85.2% success rate and 80.1% prediction rate of the produced results. The findings can be used by concerned authorities to protect coastal erosion and minimise its effects on properties and coastal environments.

Coastal Management Software to Support the Decision-Makers to Mitigate Coastal Erosion

There are no sequential and integrated approaches that include the steps needed to perform an adequate management and planning of the coastal zones to mitigate coastal erosion problems and climate change effects. Important numerical model packs are available for users, but often looking deeply to the physical processes, demanding big computational efforts and focusing on specific problems. Thus, it is important to provide adequate tools to the decision-makers, which can be easily interpreted by populations, promoting discussions of optimal intervention scenarios in medium to long-term horizons. COMASO (coastal management software) intends to fill this gap, presenting a group of tools that can be applied in standalone mode, or in a sequential order. The first tool should map the coastal erosion vulnerability and risk, also including the climate change effects, defining a hierarchy of priorities where coastal defense interventions should be performed, or limiting/constraining some land uses or activities. In the locations identified as priorities, a more detailed analysis should consider the application of shoreline and cross-shore evolution models (second tool), allowing discussing intervention scenarios, in medium to long-term horizons. After the defined scenarios, the design of the intervention should be discussed, both in case of being a hard coastal structure or an artificial nourishment (third type of tools). Finally, a cost-benefit assessment tool should optimize the decisions, forecasting costs and benefits for each different scenario, through definition of economic values to the interventions and to the land/services/ecosystems, weighting all the environmental, cultural, social and historical aspects. It is considered that COMASO tools can help giving answers to the major problems of the coastal planning and management entities, integrating transversal knowledge in risk assessment, physical processes, engineering and economic evaluations. The integrated coastal zone management needs these tools to ensure sustainable coastal zones, mitigating erosion and climate change effects.

Effects of future sea level rise on coastal habitat

ABSTRACTSea level rise (SLR) and disturbances from increased storm activity are expected to diminish coastal ecosystems available to nesting species by removing habitat and inundating nests during incubation. We updated the United States Geological Survey's (USGS) Coastal Vulnerability Index, which provides a qualitative and relative assessment of a coastal area's vulnerability to erosion and shoreline retreat as a function of SLR and other factors, for the South Atlantic Bight. We considered a eustatic SLR projection of 14 cm by 2030. We linked long‐term survey data for 3 sea turtle species, 3 shorebird species, and 5 seabird species to future coastal erosion vulnerability to SLR to understand effects of future SLR on nesting habitats. Over 2,000 km (43%) of the South Atlantic Bight coastline is projected to have an increase in coastal erosion vulnerability by the 2030s, with respect to its present vulnerability. Future vulnerability of SLR‐induced erosion along the South Atlantic Bight is spatially variable, and the 11 coastal study species also varied in their use of coastal habitats with high future coastal vulnerability to SLR. For example, only 23% of high‐density nesting habitat for the brown pelican (Pelecanus occidentalis) is expected to be at increased vulnerability to SLR, whereas >70% of the high‐nesting density habitat for 2 seabird species (gull‐billed tern [Gelochelidon nilotica], sandwich tern [Thalasseus sandvicensis]) is predicted to have higher future coastal erosion vulnerability by 2030. We provide predictions for the level of susceptibility of the study species to erosion from future SLR, which is the first step in managing coastal species for the changing environmental conditions associated with climate change and SLR. © 2019 The Authors. Journal of Wildlife Management Published by Wiley Periodicals, Inc. on behalf of The Wildlife Society.

Historical evolution of seafront occupation in France (Bay of Biscay) and Brazil (Rio de Janeiro) face to coastal erosion vulnerability and risks (19th - 21th centuries)

Intervenções antrópicas na zona costeira ocorreram em larga escala a partir do século XIX em virtude da necessidade de se acomodar embarcações cada vez maiores nas áreas portuárias e da difusão do banho de mar nas praias como um valor social. A partir do século XX intensifica-se a urbanização das zonas costeiras onde hoje se situam algumas das mais populosas cidades do mundo, bem como importantes destinos turísticos, o que resulta em enorme fluxo de pessoas para estas áreas. No presente trabalho é apresentada a evolução histórica da ocupação do litoral na cidade do Rio de Janeiro (Brasil) e na Baía de Biscaia (França) apontando sua influência sobre as transformações da dinâmica natural das praias, a vulnerabilidade e os riscos à erosão costeira. O resgate histórico inicia-se no começo do século XIX e se estende até o momento atual, enfatizando as transformações promovidas pela ocupação urbana e o uso turístico, e sua relação com os eventos de ressaca.

Liberia's coastal erosion vulnerability and LULC change analysis: Post-civil war and Ebola epidemic

In most developing countries, data for coastal change and vulnerability assessment is hard to come by due, e.g., to data inaccessibility or incomplete dataset. In some countries, e.g., Liberia, a country that was ravaged by civil war and Ebola epidemic, such extraneous factors prevent direct observations, i.e., “boots on the ground”. This study examines temporal changes in land use/land cover (LULC), coastline changes, and coastal vulnerability to erosion and their effects on Liberia over a period of 29 years (1986–2015). The results from the post-classification change detection analysis using Landsat data (validated by moderate resolution Sentinel-2 product) show that bare land and sediment classes decreased over the entire study period by 5.07% and 0.06%, respectively. Water, vegetation, and residential classes are found to have increased during the 29 years of evaluation by 0.41%, 3.29% and 1.43%, respectively. Vegetation cover during the post-civil war era (2002–2015), however, reduced by about 0.31%. Furthermore, the results for the coastal analysis indicate more erosion during the period 1998–2002, i.e., the post-civil war period. The results also show an increase in residential areas possibly due to population growth, especially in the most populated areas such as Monrovia, the capital city.

A method for modelling coastal erosion risk: the example of Scotland

It is thought that 70% of beaches worldwide are experiencing erosion (Bird in Coastline changes: a global review, Wiley, Hoboken, 1985), and as global sea levels are rising and expected to accelerate, the management of coastal erosion is now a shared global issue. This paper aims to demonstrate a method to robustly model both the incidence of the coastal erosion hazard, the vulnerability of the population, and the exposure of coastal assets to determine coastal erosion risk, using Scotland as a case study. In Scotland, the 2017 Climate Change Risk Assessment for Scotland highlights the threat posed by coastal erosion to coastal assets and the Climate Change (Scotland) Act 2009 requires an Adaptation Programme to address the risks posed by climate change. Internationally, an understanding and adaption to coastal hazards is imperative to people, infrastructure and economies, with Scotland being no exception. This paper uses a Coastal Erosion Susceptibility Model (CESM) (Fitton et al. in Ocean Coast Manag 132:80–89. https://doi.org/10.1016/j.ocecoaman.2016.08.018 , 2016) to establish the exposure to coastal erosion of residential dwellings, roads, and rail track in Scotland. In parallel, the vulnerability of the population to coastal erosion, using a suite of indicators and Experian Mosaic Scotland geodemographic classification, is also presented. The combined exposure and vulnerability data are then used to determine coastal erosion risk in Scotland. This paper identifies that 3310 dwellings (a value of £524 m) are exposed to erosion, and the Coastal Erosion Vulnerability Index (CEVI) identifies 1273 of these are also considered to be highly vulnerable to coastal erosion, i.e. at high risk. Additionally, the CESM classified 179 km (£1.2 bn worth) of road and 13 km of rail track (£93 m to £2 bn worth) to be exposed. Identifying locations and assets that are exposed and at risk from coastal erosion is crucial for effective management and enables proactive, rather that reactive, decisions to be made at the coast. Natural hazards and climate change are set to impact most on the vulnerable in society. It is therefore imperative that we begin to plan, manage, and support both people and the environment in a manner which is socially just and sustainable. We encourage a detailed vulnerability analysis, such as the CEVI demonstrated here for Scotland, to be included within future coastal erosion risk research. This approach would support a more sustainable and long-term approach to coastal management decisions.