Coastal Slope Research Articles

Coastal vulnerability index for the indented coastline of Primorje-Gorski Kotar County, Croatia

The study explores the general vulnerability of the coastline, with a focus on assessing vulnerability using the coastal vulnerability index (CVI) along the highly indented coastline of Primorje-Gorski Kotar County (PGC), Croatia. Vulnerability was assessed every 25 m of the 1235 km long coastline by calculating the CVI based on five representative variables: geological setting, coastal slope in relation to terrain instabilities (rockfalls and landslides), significant wave height, coastal flooding, and beaches, which were also integrated into a single overall CVI. The length of the coastline, characterised by different relief forms, and the scale of available data required an adaptation of the commonly used methodology. The results show a low overall vulnerability, mainly due to the prevalence of relatively resistant carbonate sedimentary rocks along the coasts. However, almost a quarter of the investigated coastline is highly or very highly vulnerable to coastal flooding. Of particular concern is the fact that many of the most vulnerable areas are inhabited. Analyses at this scale are suitable for regional spatial planning. The results of the conducted research are available publicly online, which enables their practical application for planning and management of coastal areas. Adaptation to the impacts of climate change is highly dependent on the location itself, but overall, this assessment provides indications of the most vulnerable locations in the PGC, where it is necessary to limit interventions in the coastal area.

IC-IE-AKS-O: an automatic recognition method for coastal slope landslide areas

Automatically and accurately identifying the deformation zone of coastal slope landslides is crucial for exploring the mechanism of landslides and predicting landslide disasters. To this end, this study proposes an integrated automatic recognition method combining Image Clipping (IC), Image Information Enhancement (IE), Adaptive K-means Clustering Segmentation (AKS), and Optimization (O): IC-IE-AKS-O, which achieves precise extraction of the deformation area in coastal slope landslide images. Firstly, due to the more complex natural environment of field slopes, to extend the monitoring duration, we introduce a hierarchical operation algorithm based on the HSV color model, which effectively mitigates the impact of sunlight, rain, and foggy weather on image recognition accuracy. Secondly, this study proposes a 2D landslide image segmentation technique that combines K-means clustering with global threshold segmentation for landslide images, enabling the segmentation of small image regions with precision. Finally, we combine image information enhancement technology with image segmentation technology. To verify its effectiveness, we identify a landslide image of a coastal slope in Pingtan. The method displays an average relative error of 5.20% and 5.14% in the X and Y directions, respectively. Its advantages are threefold: (1) The combination of image information enhancement and segmentation techniques can more accurately identify landslide areas that appear blurred in the image; (2) expanding the temporal dimension of coastal slope monitoring; (3) providing excellent boundary conditions and segmentation results. The practical application of this method ensures the stable and accurate operation of the coastal slope monitoring system, providing a safeguard for the sustainable development of marine safety.

Coastal Vulnerability Index (CVI) Assessment: Evaluating Risks Associated with Human-Made Activities along the Limassol Coastline, Cyprus

Coastal risk assessment is crucial for coastal management and decision making, especially in areas already experiencing the negative impacts of climate change. This study aims to investigate the coastal vulnerability due to climate change and human activities in an area west of the Limassol district’s coastline, in Cyprus, on which there have been limited studies. Furthermore, an analysis is conducted utilising the Coastal Vulnerability Index (CVI) by exploiting eight key parameters: land cover, coastal slope, shoreline erosion rates, tidal range, significant wave height, coastal elevation, sea-level rise, and coastal geomorphology. These parameters were assessed utilising remote sensing (RS) data and Geographical Information Systems (GISs) along a 36.1 km stretch of coastline. The results exhibited varying risk levels of coastal vulnerability, mainly highlighting a coastal area where the Kouris River estuary is highly vulnerable. The study underscores the need for targeted coastal management strategies to address the risks associated with coastal erosion. Additionally, the CVI developed in this study can be exploited as a tool for decision makers, empowering them to prioritise areas for intervention and bolster the resilience of coastal areas in the face of environmental changes.

Effect of soil hydrological conditions on rainfall erosion on coastal saline soil slopes

Effect of soil hydrological conditions on rainfall erosion on coastal saline soil slopes

Evaluation of coastal risks to Sea level rise: Case study of Nile Delta Coast

One of the most effective strategies for coastal management in Egypt is analyzing how the Nile Delta shoreline is adapted for climate change and rising sea levels and identifying the most vulnerable and hotspot sites. Thirteen geological, physical, and socioeconomic factors were identified and assessed to ascertain the level of vulnerability of the Egyptian Delta coast. The rank for each parameter was integrated using two different techniques (Gornitz’s method and Analytical hierarchy process, AHP) to estimate the coastal vulnerability index, CVI. Based on the CVI, similar values gained from both models (72 % correlated), the Nile Delta shoreline is categorized into five vulnerability levels (very high, high, moderate, low, and very low), with about 20 % equal predomination for each. The most vulnerable region is Abo-Khashba Bay, with approximately 60 % of the shoreline bay categorized as very high vulnerability. By contrast, the moderate-very low vulnerability categories predominate the Burullus headland (more than 75 % of the shoreline). The study also reveals that the factors that most influence the vulnerability level in the study area are geomorphology, land elevation, coastal slope, bathymetry, wave exposure, the presence of artificial structures, and land use changes. The findings outlined in this study are significant for future development and could be a basis for future decision-making to prevent further damage to the Nile Delta shoreline.

Study into the reshaping process of large reservoir banks using remote sensing

Background. During the first 10—20 years after the creation of large reservoirs, the process of processing of coastal territories is activated, which leads to the loss of land resources, has a negative impact on the existing coastal infrastructure and changes in the depth of the reservoir as a result of activation of the process of rock accumulation, destruction of coastal slopes. Shoreline retreat is 10—15 meters per year. The paper considers the process of recycling of reservoir banks on the example of the Volgograd reservoir.Aim. Development of a methodology for studying and forecasting the process of reshaping of reservoir banks using remote sensing.Materials and methods. The data of 1980—1990 on the actual magnitude of bank reprocessing of the Volgograd reservoir were collected, processed and analyzed, and the coastal territory was typified. It is proposed to use remote sensing materials to obtain the values of coastal overbanking for the period from the 1990s to the present time. Forecasting of the process of reformation of reservoir banks is carried out on the basis of application of mathematical statistics methods.Results. On the basis of solving the set tasks, a universal new methodology for studying and forecasting reservoir bank reformation was proposed. The methodology was tested on the materials of the Volgograd reservoir.Conclusion. The proposed new methodology makes it possible to obtain data on the dynamics of the Volgograd reservoir bank reformation process and to make a forecast for the next 10 years. This methodology can be used to study the process of bank reformation of large reservoirs.

Assessment of shoreline dynamics and vulnerability along the Central Kerala Coast using a geospatial approach

Coastal areas are susceptible to coastal processes, such as sea level rise and natural disasters, making them highly dynamic and vulnerable. The study examines factors such as shoreline changes, coastal slope, wave height, tidal range and landforms and shows distinct erosion, accretion and stability patterns across six littoral cells. Coastal slope and sea level rise are crucial for vulnerability assessment, with low slopes and rising sea levels indicating areas of higher risk. The Coastal Vulnerability Index categorizes zones as low, medium and high risk based on physical variables, while the linear regression method calculates an average shoreline change of −2.41 m/year erosion and 2.59 m/year accretion from 1990 to 2015. The results show that 68.14% of the shoreline is classified as low risk, 17.82% as stable and 14.18% as high risk.

Seismic analysis of coastal slope stability considering strength nonlinearity and tension cut-off

Tensile stresses may lead to cracks forming at the crest of coastal slopes and subsequent slope failure, particularly under seismic load conditions. Traditional shear strength failure criteria often overestimate the tensile strength of geomaterials, and in turn the factor of safety against sliding. This paper presents an improved nonlinear analysis method for assessing the stability of slopes, while considering tension cut-off in the failure criterion as well as the detrimental effects of inertial seismic loading and pore water pressure. The method employs the principle of energy consumption to obtain solutions for the geometry of the potential sliding surface and stress distribution, while the critical slope height and the stability factor are determined by means of a particle swarm optimization algorithm. Comparison with existing methods is conducted to validate the effectiveness and accuracy of this method. Results showed that the tensile strength of geomaterials had a significant impact on the stability of the slope and its associated failure mechanism, particularly for the vertical slope. This study could avoid the assumptions of the dilatancy angle on the velocity discontinuity and critical slope sliding surface, and reflect the tensile and nonlinear characteristics of the geomaterials well.

Evaluating Sea Level Rise Impacts on the Southeastern Türkiye Coastline: a Coastal Vulnerability Perspective

Coastal areas are inherently sensitive and dynamic, susceptible to natural forces like waves, winds, currents, and tides. Human activities further accelerate coastal changes, while climate change and global sea level rise add to the challenges. Recognizing and safeguarding these coasts, vital for both socioeconomic and environmental reasons, becomes imperative. The objective of this study is to categorize the coasts of the Mersin and İskenderun bays along the southeastern coast of Türkiye based on their vulnerability to natural forces and human-induced factors using the coastal vulnerability index (CVI) method. The study area encompasses approximately 520 km of coastline. The coastal vulnerability analysis reveals that the coastal zone comprises various levels of vulnerability along the total coastline: 24.7% (128 km) is categorized as very high vulnerability, 27.4% (142 km) as high vulnerability, 23.7% (123 km) as moderate vulnerability, and 24.3% (126 km) as low vulnerability. Key parameters influencing vulnerability include coastal slope, land use, and population density. High and very high vulnerability are particularly prominent in coastal plains characterized by gentle slopes, weak geological and geomorphological features, and significant socioeconomic value.

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

Bangladesh is a maritime nation situated on the northern side of the Bay of Bengal (BoB), blessed with substantial natural resources and opportunities. However, natural disasters and climate-induced hazards are threatening these opportunities as well as destroying the recourses. Coastal vulnerability assessment aids in the prevention of loss of life and resource devastation since it provides forewarning of impending calamitous consequences and facilitates taking mitigative measures. The study has endeavored to make a composite coastal vulnerability index (CVI) for the exposed coast of the southeastern coastal region of Bangladesh, combining physical and social vulnerability indexes using several physical and social parameters. The CVI was developed by using nine physical parameters, namely (a) Coastal Elevation, (b) Coastal Slope, (c) Annual Average Rainfall, (d) Storm Surge Height, (e) Soil Salinity, (f) Average Wind Speed, (g) Rate of SLR, (h) Soil Permeability, (i) Mean Tidal Range and six social parameters namely (a) Literacy rate, (b) Household Structure, (c) Land Use Land Cover (LULC), (d) Population Density (e) Number of Disabled People and (f) Number of Population (Age: <5 & >65). With the aid of field and secondary data, thematic layers of each physical and social parameter were prepared by defining five distinct vulnerability classes (i.e., very high, high, moderate, low, and very low) and assigning vulnerability ranks. The final CVI was estimated using geospatial techniques such as GIS and remote sensing, coupled with Physical Vulnerability Index (PVI) and Social Vulnerability Index (SVI), and relevant values were categorized into five distinct groups as before. The findings show that 25.9% of the exposed coast in the southeast coastal region, which comprises Banshkhali, Chakaria, Maheshkhali, and Cox's Bazar Sadar is high to very high vulnerable to multiple hazards. Comparatively, 28.29% have been classified as moderately vulnerable, and the remaining 45.8% in the areas of Hathazari, Mirsharai, Sitakunda, Sandwip, and Chittagong City (Kotwali), Kutubdia show that they are very low to low vulnerable to such multi-hazards. Based on this vulnerability assessment result, sustainable coastal management policy-making and development planning can be taken to mitigate the risk and loss of the southeastern coastal region due to climatic hazards and natural disasters such as floods and storm surges. The outcome information will also help to make an Integrated Coastal Zone Management (ICZM) plan for the proper and sustainable utilization of the coastal resources. Additionally, it will assist as ground information to establish a framework for prioritizing community resilience-building initiatives or developing appropriate adaptation strategies to lower catastrophe risk.

Assessment of coastal vulnerability index (CVI) and its application along the Labuhan Maringgai coast, east Lampung Indonesia

The Coastal Vulnerability Index (CVI) is one of the simplest and commonly used methods to assess coastal vulnerability. In this way, it is a common tool contributing to the decision-making process in long-term coastal planning and management. This study aims to assess the level of coastal vulnerability according to coastal typology of Labuhan Maringgai Coast section. The variable formulation of CVI is divided into hydrodynamic factors (mean significant wave heights, mean tide range, and mean sea level rise) and morpho dynamics factors, i.e. geomorphology, coastal slope, and average width of emerged beach. The morpho dynamics data were obtained through observation, direct measurements in the field by systematic sampling, extraction from aerial photographs and digital surface model (DSM). The results of modelling and predictions by several agencies are derived to obtain the hydrodynamics data. The coast of Labuhan Maringgai was divided into 12 transects and the coastal vulnerability index were classified into three categories such as low, moderate, and high. The results of CVI method showed that the most vulnerable transect is located at Desa Bandar Negeri characterized by mud flats and damaged mangroves.

Effect of sea level drawdown on coastal clay slope stability considering two strength criteria

For coastal slopes, the effects of sea level drawdown on slope stabilities with linear and nonlinear criteria are lack of research. This paper employed tangential method to carry out limit analysis for coastal slope stability with Power-law criterion. The upper bound solutions were derived on base of work-energy equations for two cases of sea level rapid drawdown and sea level slow drawdown. For two slope examples, presented comparative charts illustrated that slope critical height associated with nonlinear or linear criterion decreases in case of sea level rapid drawdown. As sea level rapidly drops near slope toe, using linear criterion will significantly overestimate the stability of steep slopes. The slip surface with nonlinear criterion becomes shallower, and the slip surface with linear criterion becomes deeper first and then remains unchanged. Under the condition of sea level slow drawdown, nonlinear and linear solutions decrease first and then increase, and their maximum declines reach about 34% and 42%, respectively. The slip surfaces associated with nonlinear and linear criteria both become slightly shallower. 3D geometry has a more obvious impact on the stability of gentle slopes with B/H ≤ 15. The presented results can provide guidance on disaster prevention and control for coastal slopes.

Slope stability analysis of coastal geotechnical structures under combined effects of earthquake and rainfall

The primary factors responsible for inducing landslide disasters are earthquakes and rainfall. Using the strength reduction method within the finite element analysis software Abaqus, a study was conducted to analyze the stability of coastal geotechnical slopes. This investigation considered the combined influence of rainfall and earthquakes, taking into account the geological conditions and characteristics specific to these coastal areas. The results indicate that, under the same seismic acceleration amplitude, the shear strength of the slope soil gradually decreases as the water content increases, resulting in a decrease in the stability coefficient. Similarly, with a constant water content in the slope, an increase in seismic acceleration amplitude leads to heightened soil shear stress, consequently decreasing the stability coefficient. Maintaining constant water content while increasing seismic acceleration results in elevated soil shear stress, reduced shear strength, and a subsequent decrease in the stability coefficient. The simultaneous occurrence of intense rainfall and a strong earthquake pushes the slope to its most precarious state, causing the most significant reduction in the stability coefficient. Incorporating anti-slip piles substantially enhances the slope’s stability coefficient, and an optimal arrangement of anti-slip piles for the most unfavorable conditions is proposed.

ВЛИЯНИЕ ТЕМПЕРАТУРЫ ВОЗДУХА, КОЛИЧЕСТВА ОСАДКОВ И УРОВНЯ ВОДЫ НА БЕСПОЗВОНОЧНЫХ ПРИБРЕЖНОЙ ПОЛОСЫ ЗЕЙСКОГО ВОДОХРАНИЛИЩА

The authors presents the results of analysis concerning the weather conditions and water level affect on the invertebrates number in the Zeya Reservoir, noted in the inventory for 2011–2023, on the «experiment» and «control»coastal slope areas. It is found that rising water levels in reservoirs influence the number of certain taxa from the pedobionts group. The current year temperature and precipitation have had an evident affect on the number of invertebrates and macrotaxonomic richness and diversity indices (MTD) within the reservoir zone (the «experiment» site). There is a correlation between the MBR indices and those of the current year precipitations in the «living Gilyuya» zone (the «control» area); the influence of other parameters is small. The influence of last year weather conditions has not been identified.

Geoecological and economic consequences of creation, drainage and possible variants of restoration the Kakhovsky reservoir

In the article, in the aspect of engineering and geological safety of structures and communications, the long-term hydrogeological consequences of the support and drainage effects at coastal areas of destroyed Kakhovsky hydro node reservoir as a leading eco-forming component of a giant natural and man-made geosystem are considered. In particular, it included Zaporizhia NPP, the largest in Europe, and the largest irrigation systems in Ukraine. The consequences of the hydrodynamic disaster due to explosion of Kakhovskaya HPP, the dynamics and current state of drainage of the bed of its reservoir are briefly described, according to the data of GIS analysis of space images. And also – the state of hydrogeological and engineering-geological conditions in the reservoir support zone at the time of disaster and in retrospect. A calculated assessment of changes in hydrogeological conditions for the next 10-15 years has been carried out. Long-term natural and man-made threats that arose as a result of such changes in hydrogeological (geofiltration and geodynamic) conditions are named. The set of socio-economic threats that arose due to the negative consequences of Kakhovsky reservoir existence and draining is described. It is emphasized that the restoration of hydrotechnical and water management parameters of the reservoir in the previous values (according to the conservative version) will lead to secondary geospatial water saturation of subsiding loess-loamy silty-clay floatingable rocks that have already undergone deformations due to a decrease in geotechnical stability during the initial flooding and subsequent drainage. This will start a new stage in the formation of dangerous violations of stress-deformed state of coastal slopes, of Zaporizhzhya NPP responsible structures foundation and in nearby cities and towns. A socially and ecologically favorable option for the rehabilitation of affected region is possible only on the modern European ideological and technological basis of taking into account the maximum permissible changes in the hydrological network, i.e. by means of: creating a cascade of low support channel reservoirs with locks and small hydroelectric power stations, reconstruction of riverside ponds and water supply systems, transfer of domestic water supply to underground sources, irrigated lands – for drip irrigation, ecological reclamation and afforestation of drained lands.

Evolution of an earthquake-induced landslide complex in the South Island of New Zealand: How fault damage zones and seismicity contribute to slope failures

Abstract Tectonic deformation within fault damage zones can influence slope stability and landslide failure mechanisms due to rock mass strength effects and the presence of tectonic structures. Here, we used detailed site investigations to evaluate controls on deformation within the Half Moon Bay landslide complex, located ~1 km from the surface trace of the Hope fault in the South Island of New Zealand. During the 2016 Mw 7.8 Kaikōura earthquake, the slope experienced up to ~13 m of displacement and partially transitioned into a rock avalanche (with a volume of ~350,000 m3). Deep-seated deformation of the entire slope predated the 2016 earthquake. Results of geomorphological analysis, field mapping, geophysical surveys, slope displacement, and a 60-m-deep borehole in the incipient portion of the landslide indicated the presence of a subvertical tectonic fabric and intense fracturing and weathering of the rock mass, which gradually decrease with depth. Based on these results, we established a conceptual model wherein the landslide failure mechanism is a combination of flexural toppling along the subvertical structures coupled with joint-step-path sliding along preexisting, closely spaced discontinuities within the graywacke rock mass. Coseismic slope displacements revealed a large area of incipient failure behind the headscarp of the 2016 rock avalanche, which will likely result in further avalanching at the site. This case study demonstrates that inherited tectonic structures (combined with seismicity and weathering in an oversteepened coastal slope) play an important role in the evolution of hillslopes near active faults.

Coastal rocky slopes instability analysis and landslide frequency-area distribution alongside the road network in west Mediterranean context (northern of Morocco)

Coastal rocky slopes instability analysis and landslide frequency-area distribution alongside the road network in west Mediterranean context (northern of Morocco)

The influence of environmental factors on the composition of the petrophytic-steppe communities in the south of the Sverdlovsk and in the north of the Chelyabinsk regions

The investigated petrophytic-steppe communities of the Middle Urals do not belong to the zonal vegetation type. Their growth in the region is associated with an unusual combination of environmental conditions - well-drained, well-heated rocky riverbank slopes of the southern and close exposures of slopes. The aim of the work was to identify the key environmental parameters that determine the composition and structure of petrophytic-steppe communities in the south of the Sverdlovsk and north of the Chelyabinsk regions. The communities of the coastal slopes of the Iset, Bagaryak, Patrushikha, Sysert and Neiva rivers were studied. An array of 74 geobotanical releves of communities from 8 plots was collected, considering environmental factors, and the composition and structure of plant communities on plots of 1 m2 were also detailed. Using the CCA method of ordination, the contribution of environmental parameters to the variation in vegetation cover characteristics was estimated. It was shown that the parameters characterizing the type of rocks, as well as indicators of the amount of precipitation, have the greatest contribution. Four variants of combination of species in the studied communities, gravitating to certain sets of environmental parameters, were identified, for each of the groups a stable composition of dominant species was noted, and species characterized by a high level of constancy were identified.

Indeks Kesesuaian Wisata Pantai Batu Bolong, Canggu, Badung

The tourism suitability index (TSI) is criteria of resources and the environment to meet the needs of tourism development. The tourism suitability index research was carried out at Batu Bolong Beach, Canggu with the aim of knowing tourism suitability index and tourism area utilization zone for beach recreation activities. Method used field observation by purposive sampling at 4 station points which are divided into a beach length of 640 m. Data retrieval in the form of 10 parameters: water depth, beach type, water current velocity, coastal slope, water base material, beach width, water brightness, dangerous biota, fresh water availability, and coastal land cover. Tourism suitability analysis based on TSI matrix with considering classification of four types categories. The limiting factors at Batu Bolong Beach are the brightness of the waters and the closure of coastal land. The value of tourism suitability for tourism activities in the beach recreation category based on assessment of stations I, II, III, and IV are different, namely 98.80%, 94.04%, 95.23%, and 91.67%. So this indicates that each station in the coastal area can be declared very suitable category for recreational tourism activities. The zones for use of coastal tourism areas include sports, walks, sunbathing, swimming, and surfing. The sunbathing, walking, swimming, and surfing zones can be done at all stations, while the sports zone can be done at stations I and IV. The sacred zone is located in the northern area, stations I and III which are adjacent to station II.

Forecast of changes in the beach condition of the Yuzhne city under the influence natural factors

The study of the factors of degradation and the forecast of the state of recreational areas of the coast to prevent their negative changes is relevant. Purpose. Forecast of changes in the condition of the Yuzhne beach, provision of general proposals for its protection from degradation. Methods. Mathematical statistics, linear analysis and mathematical modeling, comparative analysis, cartographic and grapho-analytical studies. Results. The beach of Yuzhne is located on the coast of the Black Sea. Its length is approximately 700 m. The southern direction in the sector 180±22.5⁰ is dangerous for waves. The distance from the beach to the opposite shore (wave acceleration) is 540-610 km. The boundary between the shallow and deep water zones is at a distance of approximately 200 km with a depth of 75 m. With southerly winds, recurring once every 25 years, on the approach to the shallow water zone with a depth of 50-75 m, a developed disturbance with extreme wave parameters is formed, which, transforming in the shallow water zone, significantly affects the coast. A profile of relative dynamic equilibrium with a length of 1,200 m and a depth at this distance of 11.2 m is formed during the calculated disturbance. From the water cut, the boundary between the near-cut and surf zones is located at a distance of 220 m with a depth of 3.6 m. Regardless of the standing water level, the calculated storm destroys the original shore at the extreme parts of the beach. When the sea level is high, the disturbance moves the destroyed material with the beach material into the cut-off zone, while the water cut at the 0.0 m BS mark does not change its planned location. The amount of beach material on the upper part of the coastal slope may decrease significantly. At an average level of the sea, the washing away of destroyed and beach material is accompanied by the advance of the water cut toward the sea for a distance of up to 20 m, but at the same time, a decrease in beach material on the above-water part of the coastal slope is also observed. Conclusion. Without taking special protection measures, the beach of the Yuzhne city will degrade in the future. In areas of the beach, in order to prevent its erosion, it is necessary to erect a retaining wall with a backfilling layer. An option for an active method of protection can be the construction of permeable bunkers on the beach or an intermittent breakwater at a distance from the shore. Such protection will not impede the alongshore transport of sand. Dunes or waves will contribute to the accumulation of sand on the beach. At the same time, after strong storms from the southern direction, with high sea level, episodic additions of sand to the beach are necessary