Coastal Sector Research Articles

Analysis of the Rockfall Phenomena Contributing to the Evolution of a Pocket Beach Area Using Traditional and Remotely Acquired Data (Lo Zingaro Nature Reserve, Southern Italy)

The coastal domain of central western Sicily is characterized by the presence of rocky coasts, which mainly consist of pocket beaches situated between bedrock headlands that constitute ecological niches of great touristic and economic value. In this peculiar morphodynamic system, the sedimentary contributions are mainly derived from the rockfall that affects the back of nearby cliffs or the sediment supply of small streams that flow into it. In this study, we investigated the geomorphological processes and related landforms that contribute to the evolution of a pocket beach area located in a coastal sector of NW Sicily Island. The cliffs in this are affected by several rockfalls, and deposits from these rockfalls also add to the rate of sedimentary contribution. The analysis was conducted through the application of traditional approaches and contemporary methods that have previously been used to forecast the collection of input data in the field, often under difficult conditions due to the accessibility of the sites, and which have been supported by UAV surveys. Through the analysis of the digital models of terrain and orthophotos, geometrical and multitemporal analyses of landforms were carried out. A dedicated software was utilized for the detection of rockfall runout zones and block trajectories and for defining the automatic extraction of rock mass discontinuities. The data were compared with those derived from traditional geomechanical surveys. The availability of the existing and acquired remote sensing data proved essential for this study for both defining the reference geological model and for performing the site-specific analysis of rockfall.

On the development of Sand Deposits in the Southern Part of the Curonian Spit

As part of paleogeographic studies on the Curonian Spit (geological section GS 024), a coastal section was studied from the sea in the area of the village Lesnoy in the place where relic lagoon oozes come out. The granulometric, chemical and mineral compositions of slope sands were studied for the first time. The heterogeneity of the conditions for the formation of sand strata was confirmed. A high probability of a secondary change in the composition of sediments as a result of weathering processes was revealed. The results of the study indicate a gradual advance of sand deposits on the coastal part of the lagoon, which began about 10 thousand years ago. Differentiation of the sand stratum into the lower and upper parts relative to the interlayer-marker of coarse-grained sand identified in the section may reflect different stages of generation of the sand stratum: from the supposed shallow swell formed during sea level rise to beach and eolian sands.

Study on Seismic Response and Vibration Reduction of Shield Tunnel Lining in Coastal Areas

The construction of subway tunnels in the coastal section is affected by special soil quality, with complex construction conditions of unstable soil and vulnerability to groundwater corrosion. The design difficulty of subway tunnels is greatly increased, and the safety performance in the event of an earthquake is greatly reduced. To study the changes in shield tunnel lining structure under earthquake and propose damping measures, ANSYS software is used to conduct tunnel soil numerical simulation. Firstly, static analysis and modal analysis are carried out, and it is found that the maximum displacement deformation occurs at 3.8 cm of the arch crown, and the maximum stress occurs at 2.6 × 107 Pa of the left and right wall corners, 8 easily deformed points are obtained at the same time. Input EI_Centro EW forward 19 s seismic wave is used to analyze the displacement, acceleration and stress vibration characteristics of tunnel lining. The upper part of the lining is more vulnerable to earthquake, and the right arch waist is subject to the maximum stress, reaching 1.37 × 10−4 Pa, the maximum displacement deformation point is 3.65 × 10−10 m at the right wall. To reduce the impact of earthquakes on tunnel lining, the damping scheme of adding an isolation layer is adopted. Using foam concrete isolation material can reduce the stress of the arch waist by 74.6%, and rubber isolation material can reduce the stress by 80%. In consideration of groundwater corrosion and subsequent engineering construction, it is recommended to use foam concrete as the material for the isolation layer. This study can provide a theoretical basis for the design of metro tunnels in offshore areas.

Assessment of local coastal vulnerability based on a global model: A case study in Jaguaruna, southern Brazil

Coastal vulnerability is the trend of the coast to respond negatively to hazards. The vulnerability to which the coastal zone of the Municipality of Jaguaruna is exposed is linked to the propensity to suffer damage or loss to erosion, flooding, and storm waves. The Jaguaruna shorefront was chosen because it has shown, over the years, an unplanned urban sprawl. Regarding the populational aspect, the study area is predominantly occupied in summer periods, characterized as a space for the construction of second residences. This problem made the environment especially vulnerable. Furthermore, the research becomes important as this study area is part of the Right Whale Environmental Protection Area. To assess the most exposed locations, a multicriteria coastal vulnerability index was generated using the geometric average of biogeophysical variables and socioeconomic data of the area of interest. The results of the biogeophysical exposure index combined with the mean population distribution index allowed us to assess the coastal sectors that are most vulnerable to coastal hazards. The maximum value of coastal vulnerability was observed in Torneiro and high values in Campo Bom and some regions of Camacho. The results are effective to be used with Government, because the recognition of the most vulnerable sectors can contribute to the identification of priority areas for coastal management and even indicate areas that need a priority mitigation plan against extreme events. Furthermore, we reinforce that the human presence on the coasts of the world modifies the natural environment and contributes decisively in increasing coastal vulnerability.

Development of an integrated coastal vulnerability index and its application to the low-lying Mandarmani–Dadanpatrabar coastal sector, India

Development of an integrated coastal vulnerability index and its application to the low-lying Mandarmani–Dadanpatrabar coastal sector, India

Plio-Quaternary coastal landscape evolution of north-western Sicily (Italy)

ABSTRACT We present and discuss the results of a geomorphological and geological study aimed at reconstructing the Plio-Quaternary evolution of the NW Sicily coastal belt , a low strain rate region in the central Mediterranean Sea. We performed morphometric and field analysis of Quaternary marine terraces extracting more than 300 shoreline location points subdivided into six orders. The obtained dataset was validate by investigating the morphological changes along topographic profiles and comparing the extracted locations and elevations with the stratigraphic boundaries in the Plio-Quaternary units. We distinguished two contiguous coastal sectors characterized by different paleo-shoreline elevations and Plio-Quaternary evolution, whose estimated uplift rates fit well with the well-known, regional eastward uplift rate increase along the Northern Sicilian continental margin. Obtained results, summarized in a geomorphological map and a morpho-evolutionary model, provide new valuable data to characterize the active deformation processes and the seismotectonic setting in this critical sector of the Africa-Europe plate boundary.

Erozja polskiego wybrzeża wydmowego przez spiętrzenia sztormowe w sezonie 2018/19, w tym spiętrzenie Zeetje

This paper presents the rate of dune erosion on the Polish Baltic coast by storm surge Zeetje in January 2019. The results were based on field measurements on coast profiles located on dune sections of the Polish coast. Presented are the hydro-meteorological parameters of all storm surges that formed before Zeetje since Autumn 2018. The hydro-meteorological parameters of storm surges that occurred during this period were analised. The amount of dune retreat after selected surges was calculated. Following smaller storm surges in the fall of 2018, dune erosion was observed in erosional sections, where beaches are usually narrower and lower. The greatest erosion of the dunes was observed after the Zeetje storm, on average up to 3 m and a maximum of 10–12 m. The average and maximum erosion of the dunes varied on individual sandbars. The average dune erosion depended on the height of water inflow onto the shore during a storm and the height of the beach. Greater erosion occurred in sections with beach heights lower than the inflow of water during the storm. The average erosion of dunes at sea level above 1.3 m was 2.5–4.0 m. The maximum erosion values were observed on the western shores of the headlands located on the central and eastern coast. Dune erosion was not observed in places where the beach height exceeded 2.5 m above sea level and was higher than the maximum water inflow during storm Zeetje.

Application of GIS technologies for engineering geodynamic zoning of mountain territories

The lack in practise of applying special engineering-tectonic studies in the course of standard engineering surveys does not allow us to fully take into account the features of engineering-geological conditions of mountainous territories.In the work for the section of the Black Sea coast from Gelendzhik to Tuapse, which is part of the Afipsko-Defanovskaya orographic stage, a detailed study of discontinuous structures was carried out using cartographic constructions. The use of the GIS technology tool made it possible to carry out an overlay analysis of maps of morphometric indicators, as well as to draw up a diagram of tectonic blocks. The results showed good convergence with the data obtained earlier on a smaller scale. This provided the basis for zoning the territory according to the degree of favorability of engineering and tectonic conditions with the involvement of morphometric and tectonic features. The study of this territory was conducted for the first time and contributes to the clarification of its neotectonic structure, expanding the scope of application of structural and geomorphological methods based on GIS technologies in engineering and geological research.

A Methodological Tool to Assess Erosion Susceptibility of High Coastal Sectors: Case Studies from Campania Region (Southern Italy)

High coastal sectors constitute the most widespread coastal environment and, under the present accelerated sea-level rise scenario, are suffering huge impacts in terms of erosion. The aim of this paper is the proposal of a new methodological approach for the assessment of their susceptibility to erosive processes. The method is based on the combination of two matrices, i.e., a matrix considering the main physical elements (essentially morphological and geotechnical characteristics) that determine the proneness to erosion of a specific high coastal sector, and a forcing matrix, which describes the forcing agents affecting the considered sector. Firstly, several variables were selected to construct each one of the two matrices according to existing studies and, in a second step, they were interpolated to obtain the susceptibility matrix (CSIx). The approach was applied to Procida Island and Cilento promontory, both located in southern Italy. Results obtained were validated by comparing them with cliff retreat data obtained by means of aerial photographs and satellite images. The analysis shows that the greater part of the analyzed high coastal sectors belongs to the high-susceptibility class due to the combination of adverse morphological, geotechnical and forcing characteristics. Such sectors can be considered “hotspots” that require an increase in monitoring programs and, at places, urgent protective actions.

Plant diversity and species composition of the abandoned mines of the Iglesiente mining district (Sardinia, Italy): A restoration perspective

The ‘metalliferous ring’ of Iglesiente was for centuries the most important mining district of Italy. After a marked decline in mining activities, alternative management strategies were proposed to face issues mainly related to unemployment and environmental pollution. We focused on the coastal section of the mining district, in order to evaluate the development of vegetation after disturbance and assess the conservation value of the study area. The floristic composition in terms of species richness, number of endemics, evenness, life form diversity, vegetation and cryptogamic covers were analysed for 96 vegetation samples. Three main plant assemblages with 227 vascular plant species and 18 endemics were described. The most influential variable in determining species composition was the herbivory, which negatively affects species richness, endemic species richness and life form diversity and, positively, the evenness. Other influential variables were elevation, positively associated with species and endemic species richness, and the degree of debris/rock flow, which negatively influences species richness and life form diversity. Soil grain size positively influences evenness and negatively life form diversity and vegetation cover. The number of years of mining inactivity was only positively influencing life form diversity. Each identified community, especially those characterised by perennial herbs and small shrubs, can provide surrogate habitats for many endemic plants, which can be in turn used for phytostabilization and remediation. Further indications for strategic management of these mining environments, where policy and long-term monitoring are necessary interrelated strategies, were provided.

Dynamics of Low-Lying Sandy Coast of the Gydan Peninsula, Kara Sea, Russia, Based on Multi-Temporal Remote Sensing Data

The retreat rates of Arctic coasts have increased in recent decades at many sites, and an essential part of coasts considered accumulative before have turned erosional due to global climate changes and construction in the coastal zone. In this paper, we study a 7 km long coastal section of the western Gydan Peninsula in a new construction area. Based on the interpretation of multi-temporal satellite imagery, we assessed coastal dynamics in distinct periods from 1972 to 2020. We analyzed the geological structure of the coast as well as changes in hydrometeorological parameters with time, and considering the human impact, we proposed the main drivers of spatial and temporal variations of coastal dynamics. The studied low-lying sandy accumulative marine terrace was more or less stable in the period before construction (1972–2014). However, with the area’s development, the coast dynamics changed drastically: in 2014–2017, three-quarters of the studied area experienced retreat, and the average retreat rate amounted to 5.8 m/yr, up to 28.5 m/yr near the construction sites. We relate this coastal erosion intensification to human impact combined with the growth of hydrometeorological forcing. Although coastal erosion slowed down after 2017, the retreat trend remained. In the coming years, with Arctic climate warming, erosion of the studied coast will continue.

Deciphering natural and anthropogenic effects on the groundwater chemistry of Nago City, Okinawa Island, Japan

A qualitative assessment of groundwater resources is significant in islands that largely depend on individual aquifers. In Okinawa Island, Japan, limestone aquifers are valuable groundwater reservoirs. However, these aquifers are sensitive to contamination due to high permeability in the conduit network. Although human activity has increased in recent decades, there remains insufficient hydrological information to assess the impact of anthropogenic loading on groundwater quality in Okinawa Island. To address this, we analyzed 4 seepage, 16 river, and 14 shallow (<10 m in depth) groundwater samples to obtain baseline chemistry and anthropogenic impact information on groundwater resources in central Nago City, northern Okinawa Island. We divided the region into three landscape units: lowland (<30 m asl), eastern, and western areas. Except for a limited number of water samples collected in the eastern mountain and coastal section of the lowland, the hydrochemistry was characterized by Ca–HCO3 type, indicating carbonate weathering within limestone-bearing lithology and Quaternary deposits. Divergent water 87Sr/86Sr values (0.707723–0.712102) with lower Sr concentrations (0.1–1.6 μmol/L) in the mountains and convergent values (0.708859–0.709184) with higher Sr concentrations (0.3–17.6 μmol/L) in the lowland suggest that the water–rock interactions in the lowland aquifer composed of Quaternary deposits are mostly responsible for the hydrochemistry of groundwater resources. The local meteoric water line (δD = 6.38 δ18O + 3.36) indicated that the water originates from precipitation, the altitude effect, and evaporation. The δ15N and δ18O in NO3− indicated the addition of manure and septic waste in the lowland aquifer. The results imply that detecting source areas of anthropogenic NO3− prior to serious groundwater pollution is important (regardless of the NO3− concentration), and isotope analyses would aid in developing appropriate action plans to mitigate or prevent future water pollution by NO3− in island regions.

Rainfall conditions leading to runoff-initiated post-fire debris flows in Campania, Southern Italy

Wildfires increase surface runoff and erosional processes from short and intense rain bursts. In steep mountain watersheds, the progressive entrainment of material induced by surface runoff can lead to the formation of post-fire debris flows (PFDFs) downstream. Campania region, in Southern Italy, is heavily affected by wildfires, mostly in the period between June and September, and is also exposed to geo-hydrological hazards due to geological, topographic and climatic conditions. In this work, a catalog with spatial and temporal information on the occurrence of 113 PFDFs, that hit this region in the period 2001–2021, is presented and analyzed. The average number of events per year is 5, with a peak in 2017 (38 PFDFs). The rainfall conditions associated with the initiation of the PFDFs are reconstructed and analyzed, investigating their structure and magnitude. In particular, the return times of the peak cumulative rainfall of the triggering bursts in 10, 20, and 30 min have very short values (median values from 1.3 to 1.4 years, 75° percentiles from 2.7 to 3.2 years), indicating that these rainfall events are neither rare nor extreme, as also observed by other authors worldwide. Differences are observed in return times of the rainfall amounts and spatial distribution of the PFDFs that occurred in two sub-periods, such as “July–September” (higher rainfall magnitudes and longer return times) and “October–December” (PFDFs concentrated in the inner part of the region rather than the coastal sector). Moreover, the rainfall thresholds for the initiation of PFDFs in the study area are calculated. Interestingly, the minimum triggering conditions are similar to those observed in different geographical contexts. Finally, the triggering conditions identified in the present work are compared with the currently operating warning system in the region, finding that PFDFs cannot be correctly predicted with this system. Research outcomes reported in this work can provide reliable and effective support to reduce the risk posed by such events in the Campania region, which might increase in the near future.

Novel insights into the sea level evolution along the coast of Bozburun Peninsula (Turkey): A study on submerged Bronze Age harbor in Çamçalık

AbstractA recent discovery of a Bronze Age harbor site in Çamçalık provides new data for the relative sea level history along the coast of the Bozburun Peninsula over the last 3600 years. In this study, we compared the new and previously published data from nearby sites to determine the long‐term relative sea level changes. Further comparison of the observed sea level data and newly produced glacial isostatic adjustment (GIA) models clarified the tectonic contribution to the relative sea level changes. Our results suggest a nonlinear tectonic subsidence trend in the coastal zone since 3600 B.P. The increase in the relative sea level accelerated over the last 1400 years, mostly due to the seismic events controlled by the tectonic regime of the southeastern Aegean Sea. We can conclude that, as in the past, this active tectonic process will have a major impact on the future sea level evolution of the coastal sector of the Bozburun Peninsula. Notably, our study can be used to understand the historical trend of sea level rise while providing a foundation for future trend prediction.

Risk Assessment of NH3 and H2S in Coastal and Complex Sectors in Egypt by Using AirQ+ Software

The aim of the present study is to assess the health risks of NH3 and H2S gases in two different sectors in Egypt, one of them is a complex sector (represents a residential, industrial and agriculture sector) and the other is a coastal tourism sector. Hospital admissions respiratory disease (HARD) cases living in the two Sectors was also estimated during one year, due to exposure to NH3 and H2S gases using the AirQ+ Software. Concentration levels of gaseous pollutants (NH3 and H2S) were measured from December 2019 to November 2020.&#x0D; Daily mean concentrations of NH3 and H2S at the mixed sector (68.15, and 50.06 µg/m³, respectively) were higher than those in the coastal sector (23.92 and 24.10 µg/m³, respectively). The daily mean concentrations of NH3 in both sectors were less than the Egyptian and international Permissible limits.&#x0D; Non-carcinogenic risk (HQ) of H2S in the mixed region was higher than 1; indicating high adverse chronic health effects occur due to exposure to H2S according to US EPA. In addition, the estimated number of hospital admissions respiratory diseases (HARD) Cases per 100,000 population living were 3 (1 - 6) and 4 (2 - 7) for NH3 and H2S, respectively in the coastal sector, while they were 392 (358 - 410) and 569 (347 - 576) for NH3 and H2S, respectively in the mixed sector. Finally, Air Q+ Software is a valid and reliable tool for estimating short-term risk effects of NH3 and H2S, and can predicts hospital admissions respiratory diseases (HARD) cases attributed to NH3 and H2S gases.

Diet and debris ingestion of skuas on Fildes Peninsula, King George Island, Antarctica.

Using pellet analysis, we characterized the diet and plastic and non-plastic debris ingestion of skuas (Catharacta spp.) during 2017-2020 summer seasons along the coastal sector of Fildes Peninsula (King George Island, Antarctica). In addition, we conducted the same analysis during the 2020 breeding season on reproductive territories of south polar (Catharacta maccormicki) and brown (Catharacta antarctica lonnbergi) skua. Our results confirm the generalist and opportunistic habits of both skua species. Additionally, it has been proposed that brown skua displaces south polar skua from penguin breeding colonies given its higher competitive abilities, and our results suggest this might not have happened during the study period. Along with evidence from other studies, this work underlines the idea that potential local anthropogenic sources of plastic and non-plastic debris at Fildes Peninsula need to be further addressed to improve current mitigation efforts.

Anatomy of a border: transition between Southwestern Atlantic tropical and Warm Temperate marine provinces as revealed by marine mites

A previous study found that the division between the Southwestern Atlantic Tropical and Warm Temperate Provinces for marine mites do not occur in Cabo Frio (~23°S), as usually assumed in marine biogeographical studies, but somewhere around the Abrolhos Plateau and the Vitória-Trindade Chain (~20-15°S). New sampling localities along this section of Brazilian coast and sequences from mitochondrial and nuclear genes of three species or species complexes of halacarids (Agauopsis legionium, A. bilophus and Rhombognathus levigatoides) deepened the understanding of this region by showing different scenarios for the different species.

Grain size analysis and characterization of sedimentary environment of the surface sediments along the Syrian Coast, Umm al-Tuyour (Latakia)

Detailed sedimentary study of a section of the Syrian coast (Umm al-Tuyour, Latakia) was carried out in order to determine the grain size analysis and characterization of sedimentary environment. Twenty-two samples of surface sediments were collected along the coastal area during the summer period of 2022. This research used an integrated methodology of analysis and software to determine the dynamic beach environment in the study area. The observation from this study shows that the sediments are coarse to very coarse grain size, moderately sorted, near symmetrical, and finally mesokurtic. These data confirm that the deposition occurred under high-energy conditions with continuous mixing of sediments by waves and ocean currents, where erosion processes are active. The results of the linear discriminant function analysis performed on the samples indicate beach, shallow marine deposition environment and the influence of fluvial processes. Analysis of sediments using CM diagram suggests that sediment deposition is mainly by rolling under tractive current conditions.

Identification of littoral cell and its impact on shoreline dynamics along the Purba Medinipur–Balasore coastal stretch, Bay of Bengal, India: A numerical modelling and geospatial study

The northern boundary of Bay of Bengal, between Subarnarekha and Rasulpur River is divided into five coastal sectors by the four inlets, namely, Talsari, Ramnagar, Jaldha, and Pichaboni. Each sector being characterized by severe coastal erosion, beach lowering and narrow beach segments. To bring such coastal areas under proper coastal management, delineation of littoral cell and sub-cell boundaries and assessment of sediment budget is required. This study attempts to identify these hydrodynamic characteristics, by investigating the wave-induced radiation stress of dominant wave, derived from offshore wave in order to simulate longshore current and associated sediment transport using the two-dimensional deterministic MIKE 21/3 Coupled Model that is based on two dimensional shallow water, Reynolds averaged Navier–Stokes equations and fully spectral wave action conservation equation. The shoreline dynamics in terms of shoreline retreat or spit formation, is quantified by Digital shoreline analysis system (DSAS)The result of the simulation shows the dominant westerly and comparatively weaker easterly longshore flow and the resultant bed level changes. By analysing the diverging and converging flow pattern of littoral current, rate of bed level change and magnitude of shoreline oscillation, six and five littoral sub-cell (LSC) have been identified for westerly and easterly circulation respectively. The coastal inlets indirectly influence the flow direction through the development of different depositional features at mouth. Because of that inlet mouths often function as littoral cell boundaries.Periodic observation reveals that the introduction of shore-normal engineering structures has positive impact on beach nourishment and inlet stability.

Coastal inundation scenarios in the north-eastern sector of the Island of Gozo (Malta, Mediterranean Sea) as a response to sea level rise

ABSTRACT According to the most recent scenarios, sea level is expected to keep rising during the next decades because of global warming. In this context, coastal areas are highly vulnerable to marine and climate-related processes, such as erosion and inundation. Such processes are expected to cause shoreline retreat and local morphological variations with consequent loss in natural ecosystems, exploitable coastal land, and significant socio-economic impacts. This paper aims at outlining future scenarios of potential coastal inundation along the NE coastal sector of the Island of Gozo (Malta). The study assessed expected coastline positions for the investigated coastal stretch by analysing high-resolution topographic data coupled with sea level projections for the years 2050 and 2100, accounting also for the contribution of storm surges. Results are expected to sensitize local authorities and communities about potential threats derived from sea level rise that could affect coastal areas in the near future.