Search Results (95)

Boao Jade Beach, on the east coast of Hainan Island, is a typical sandy beach and is one of the areas where typhoons frequently land in Hainan. This study examined wind speed, wind direction, and sediment transport data obtained from field meteorological stations and omnidirectional sand accumulation instruments from 2020 to 2024 to study the coastal aeolian environment and sediment transport distribution characteristics in the region. The findings provide a theoretical basis for comprehensive analyses of the evolution of coastal aeolian landforms and the evaluation and control of coastal aeolian hazards. The research results showed the following: (1) The annual average threshold wind velocity for sand movement in the study area was 6.13 m/s, and the wind speed frequency was 20.97%, mainly dominated by easterly winds (NNE, NE) and southerly winds (S). (2) The annual drift potential (DP) and resultant drift potential (RDP) of Boao Jade Belt Beach from 2020 to 2024 were 125.99 VU and 29.59 VU, respectively, indicating a low-energy wind environment. The yearly index of directional wind variability (RDP/DP) was 0.23, which is classified as a small ratio and indicates blunt bimodal wind conditions. The yearly resultant drift direction (RDD) was 329.41°, corresponding to the NNW direction, indicating that the sand on Boao Jade Belt Beach is generally transported in the southwest direction. (3) When the measured data from the sand accumulation instrument in the study area from 2020 to 2024 were used for a statistical analysis, the results showed that the total sediment transport rate in the study area was 39.97 kg/m·a, with the maximum sediment transport rate in the S direction being 17.74 kg/m·a. These results suggest that, when sand fixation systems are constructed for relevant infrastructure in the region, the direction of protective forests and other engineering measures should be perpendicular to the net direction of sand transport. Full article

Accurate predictions of beach user numbers are important for coastal management, resource allocation, and minimising safety risks, especially when considering surf-zone hazards. The present work applies an XGBoost model to predict beach attendance from automatically video-derived data, incorporating input variables such as weather, waves, tide, and time (e.g., day hour, weekday). This approach is applied to data collected from Biscarrosse Beach during the summer of 2023, where beach attendance varied significantly (from 0 to 2031 individuals). Results indicate that the optimal XGBoost model achieved high predictive accuracy, with a coefficient of determination ($R^2$) of 0.97 and an RMSE of 70.4 users, using daily mean weather data, tide and time as input variables, i.e., disregarding wave data. The model skilfully captures both day-to-day and hourly variability in attendance, with time of day (hour) and daily mean air temperature being the most influential variables. An XGBoost model using only daily mean temperature and hour of the day even shows good predictive accuracy ($R^2$ = 0.90). The study emphasises the importance of daily mean weather data over instantaneous measurements, as beach users tend to plan visits based on forecasts. This model offers reliable, computationally inexpensive, and high-frequency (e.g., every 10 min) beach user predictions which, combined with existing surf-zone hazard forecast models, can be used to anticipate life risk at the beach. Full article

Rip currents at featureless beaches (i.e., beaches lacking sandbars or channels) are often hydrodynamically controlled, exhibiting intermittent and unpredictable behaviors that pose significant risks to recreational beach users. This study assessed occurrences of rip currents under a range of idealized morphology configurations and hydrodynamic wave forcing parameters using a wave-resolving Boussinesq-type model. Numerical experiments revealed that rip currents with durations on the time scale of 10 min are generated in the forms of vortex pairs, intensified eddies, mega-rips, and eddies shedding from longshore currents. In general, the key conditions that promote rip current formation at featureless beaches include shoreline curvature, headlands, moderately mild beach slopes (e.g., 0.02–0.03), normal or near-normal wave incidence, and large wave heights. Most importantly, this study highlights inherent uncertainties in rip current occurrences, particularly under conditions usually perceived as low risk: low wave heights, short wave periods, oblique wave incidence, and straight shorelines. These conditions can lead to transient rip currents and pose an unexpected hazard that coastal communities should be aware of. Full article

Coastal habitats are crucial in mitigating the impact of coastal hazards on society. However, the shortage of information about the role of these habitats in reducing floods in Rivers State, Nigeria, is limited. This study aims to assess the contribution of mangrove habitats in protecting coastal communities from flooding using the InVEST coastal vulnerability model (version 3.10.2). The model analyzes various data inputs and assigns relative numbers, ranging from 1 to 5, indicating different levels of exposure. Data on population, bathymetry, shoreline type, land use land cover, and continental shelf were obtained from relevant websites and the InVEST model package. The findings indicate that the mangrove habitats in Rivers State offer minimal protection against coastal flooding due to their degraded state caused by oil spills and over-exploitation. Additionally, sandy beaches provide little to no protection, and the socio-economic conditions in the communities contribute to increased vulnerability to flooding. The study recommends awareness programs to educate the public about the importance of mangroves for coastal protection in addition to their conservation and restoration. Full article

China has the world’s largest area of coastal aquaculture ponds, accounting for 39% of the total coastal aquaculture pond area worldwide. The rapid development of coastal aquaculture can significantly reduce global food shortages and support the development of marine economies on the Chinese mainland. However, coastal aquaculture ponds have been recognized as a beach hazard because they require pipes to be laid on the surface of the beach to discharge wastewater, polluting the beach and artificially dividing it into multiple segments. Based on a well-conceived remote sensing analysis, the erosion of beaches backed by densely distributed coastal aquaculture ponds was determined to be 10 m/y. A high-efficiency shoreline evolution model was verified using a satellite-derived shoreline dataset. For the present case, the Brier Skill Score (BSS) was calculated to be 0.55, indicating a moderate match between the modeled and satellite-derived shoreline datasets. The verified ShorelineS model was then used to predict the future evolution of a shoreline backed by densely distributed coastal aquacultural ponds. The retreat distance of the erosion hotspot was predicted to increase from 150 m in 2025 to 240 m in 2040. It is expected that the beach will lose the entirety of its dry part in the future. Potential strategies for beach protection include reasonable management and the ecological restoration and nourishment of the beach. Full article

The northern Portuguese coast has been increasingly subjected to wave-induced coastal flooding, highlighting a critical need for comprehensive overwash assessment in the region. This study systematically evaluates the total water levels (TWLs) and swash regimes over a 120 km stretch of the northern coast of Portugal. Traditional approaches to overwash assessment often rely on detailed models and location-specific data, which can be resource-intensive. The presented methodology addresses these limitations by offering a pragmatic balance between accuracy and practicality, suitable for extended coastal areas with reduced human and computational resources. A coastal digital terrain model was used to extract essential geomorphological features, including the dune toe, dune crest, and/or crown of defense structures, as well as the sub-aerial beach profile. These features help establish a critical threshold for flooding, alongside assessments of beach slope and other relevant parameters. Additionally, a wave climate derived from a SWAN regional model was integrated, providing a comprehensive time-series hindcast of sea-states from 1979 to 2023. The wave contribution to TWL was considered by using the wave runup, which was calculated using different empirical formulas based on SWAN’s outputs. Astronomical tides and meteorological surge—the latter reconstructed using a long short-term memory (LSTM) neural network—were also integrated to form the TWL. This integration of geomorphological and oceanographic data allows for a straightforward evaluation of swash regimes and consequently overwash potential. The accuracy of various empirical predictors for wave runup, a primary hydrodynamic factor in overwash processes, was assessed. Several reports from hazardous events along this stretch were used as validation for this method. This study further delineates levels of flooding hazard—ranging from swash and collision to overwash at multiple representative profiles along the coast. This regional-scale assessment contributes to a deeper understanding of coastal flooding dynamics and supports the development of targeted, effective coastal management strategies for the northern Portuguese coast. Full article

The study assesses coastal evolution and the vulnerability of archaeological sites in Southeastern Crete. Shoreline dynamics since the 1940s were examined through the interpretation of high-resolution aerial photographs and satellite images. A set of climatic variables, as well as data on geomorphological and geological factors obtained from fieldwork, images interpretation, archives, and open-source datasets, were analysed. The influence of these variables on coastal dynamics was evaluated using regression analysis, correlating their spatial distribution with rates of shoreline retreat/advance. Based on this, variables for the Coastal Vulnerability Index (CVI) calculation were selected, and the weighting for the weighted CVI (CVI_w) was determined. The classical CVI identified 13.7% of the study area’s coastline as having very high vulnerability to coastal hazards, 15.5% as highly vulnerable. In the case of CVI_w, 17.5% of the coasts of the area were classified as having very high level of vulnerability, 39.6%—as highly vulnerable. Both approaches, the CVI and the weighted CVI, highlighted the most vulnerable areas in the north, east, and southeast of Koufonisi Island, as well as the north and east of Chrisi Island. The least vulnerable areas include the wide beaches in enclosed bays, such as Gra Lygia, Ierapetra, and Ferma, along with rocky capes east of Ierapetra. Among the five archaeological sites examined, two (Lefki Roman Town and Stomio Roman Villa) fall within zones of high or very high coastal vulnerability. This study provides the first in-depth analysis of coastal dynamics and vulnerability of Southeastern Crete, a region with significant cultural heritage yet previously under-researched. Full article

This work reports the findings of an investigation aimed at assessing, for the first time, the natural and anthropogenic radioactivity content of marine sediments collected from selected areas of Sicily, Southern Italy. In particular, it focused on evaluating the average activity concentration of detected radionuclides and the radiological hazard for humans, above all considering the use of this material for nourishing actual eroded beaches. To this aim, the quantification of the average specific activity of ²²⁶Ra, ²³²Th, and ⁴⁰K natural and ¹³⁷Cs anthropogenic radioisotopes was addressed through the employment of High-Purity Germanium (HPGe) gamma-ray spectrometry. Furthermore, the absorbed gamma dose rate (D), the annual effective dose equivalent outdoor (AEDE_out), the external hazard index (H_ex), and the excess lifetime cancer risk (ELCR) were also calculated to evaluate the radiological hazard for humans related to external exposure to ionizing radiations. Furthermore, the average specific activity of ¹³⁷Cs was found to be less than the lowest detectable activity in all cases, excluding anthropogenic radioactive contamination of the investigated samples. Finally, Pearson correlation, principal component analysis (PCA) and hierarchical cluster analysis (HCA), i.e., multivariate statistics, were carried out by analyzing detected radioactivity and radiological characteristics to evaluate their relationship with the sampling locations. Full article

Erosion poses a significant threat to infrastructure and ecosystems on coastlines worldwide. Public infrastructure such as US 101—a critical conduit linking coastal communities and renowned destinations—can be costly to maintain due to erosion hazards. Erosion is episodic and varies both spatially and temporarily; hence, forecasting erosion patterns to identify vulnerable infrastructure is immensely challenging. This study presents an innovative Geographic Information Systems (GIS) algorithm to forecast sea cliff erosion progression utilizing imagery datasets (hereafter referred to as ‘rasters’). This approach is demonstrated for an approximately 300 m segment of sea cliffs near Spencer Creek Bridge in Beverly Beach State Park, Oregon, USA. First, Digital Elevation Model (DEM) rasters are created from multiple epochs of terrestrial lidar point clouds using two approaches: Triangular Irregular Networks (TINs) and Empirical Bayesian Kriging (EBK). These DEMs were integrated into a multidimensional raster to generate trend rasters. Based on these trend rasters, forecast DEMs were created based on several different combinations of training and forecast epochs. The forecast DEMs were evaluated against the original lidar data, to calculate residuals to determine optimal model parameters. It was revealed that four combinations warrant particular attention: EBK with harmonic and linear regression of trend rasters, and TIN with harmonic and linear regression of trend rasters. These methods demonstrate consistent decreases in residuals as the number of epochs used for interpolation increases. Under these circumstances, it is expected that the forecasting DEMs will exhibit residuals lower than 10 cm. This outcome is contingent on the condition that the time between the epochs used for prediction and the forecasted epochs does not increase. Full article

Environmental pollution from plastic debris is raising concerns not only for the vulnerability of marine species to ingestion but also for potential human health hazards posed by small particles, known as microplastics. In this context, marine areas suffer from a lack of constant shoreline cleanups to remove accumulated debris, preventing their degradation and fragmentation. To establish optimal strategies for streamlining plastic recovery and recycling operations, it is important to have a system for recognizing plastic debris on the beach and, more specifically, for identifying the type of polymer and mapping (e.g., topologically assessing) the distribution of plastic debris on shoreline sands. This study aims to provide an operative tool finalized to perform an in situ detection, analysis, and characterization of plastic debris present in the coastal environment (i.e., beaches), adopting a near-infrared (NIR)-based hyperspectral imaging (HSI) approach. In more detail, the possibility of identifying and classifying polymers of plastic debris by NIR-HSI in three different areas along the Pontine coastline of the Lazio region (Latina, Italy) was investigated. The study focused on three distinct beaches (i.e., Foce Verde, Capo Portiere, and Sabaudia), each characterized by a different type of sand. For each location, the adopted approach allowed for the systematic classification of the various types of plastic waste found. Three Partial Least Squares Discriminant Analysis (PLS-DA) classification models were developed using a cascade detection strategy. The first model was designed to distinguish plastics from other materials in sand samples, the second to detect plastic particles in the sand, and the third to classify the type of polymer composing each identified plastic particle. Obtained results showed that, on the one hand, plastics were correctly detected from sand and other materials (i.e., sensitivity = 0.892–1.000 and specificity = 0.909–0.996), and on the other, the recognition of polymer type was satisfactory, according to the performance statistical parameters (i.e., sensitivity = 1.000 and specificity = 0.991–1.000). This research highlights the potential of the NIR-HSI approach as a reliable, non-invasive method for plastic debris monitoring and polymer classification. Its scalability and adaptability suggest possible future integration into mobile systems, enabling large-scale monitoring and efficient debris management. Full article

Due to increasing coastal flooding and erosion in changing climate and rising sea level, there is a growing need for coastal protection and ecological restoration. Artificial sandbars have become popular green coastal infrastructure to protect coasts from these natural hazards. To assess the effect of an artificial sandbar on wave transformation over a beach under normal and storm wave conditions, a high-resolution non-hydrostatic model based on XBeach is established at the laboratory scale. Under normal wave conditions, wave energy is mainly concentrated in short wave frequency bands. The wave setup is negligible on the shoreface but becomes more significant over the beach face, and wave nonlinearity increases with decreasing water depth. The artificial sandbar reduces the wave setup by 22% and causes considerable changes in wave skewness, wave asymmetry, and flow velocity. Under storm wave conditions, as the incident wave height increases, the wave energy in the long wave frequency bands rises, while it decreases in the short wave frequency bands. The wave dissipation coefficient of an artificial sandbar increases first and then decreases with increasing incident wave height, and the opposite is true with the transmission coefficient. It features that the effect of an artificial sandbar on wave energy dissipation strengthens first and then weakens with increasing incident wave height. Additionally, an empirical formula for the wave runup was proposed based on the model results of the wave runup for storm wave conditions. The study reveals the complex processes of wave–structure–coast interactions and provides scientific evidence for the design of an artificial sandbar in beach nourishment projects. Full article

Cigarette butts (CBs) are a major source of persistent pollution in coastal ecosystems, introducing harmful chemicals and microplastics into the environment. This study assesses the ecotoxicological impact of CB leachates on Marbella Beach, Chile, by analyzing the metal contamination and its phytotoxic effects on Lactuca sativa and Lolium perenne. Three scenarios were evaluated: CBs alone, CBs mixed with sand, and sand alone. Leachate analysis revealed significant concentrations of iron and zinc, with higher toxicity observed in scenarios involving CBs. Ecotoxicological assays demonstrated that cigarette butt leachates severely inhibited seed germination and plant growth, particularly in Lactuca sativa, which showed greater sensitivity compared to that of Lolium perenne. The results underscore the partial mitigating role of sand, although it was insufficient to prevent the toxic effects of CBs. The persistence of cellulose acetate in the environment and the continued release of hazardous chemicals highlight the ecological risks posed by cigarette butt pollution. These findings emphasize the need for improved waste management strategies and the development of biodegradable cigarette filters to reduce environmental contamination in coastal areas. Full article

Beach litter, an anthropogenic and hazardous component, can interact with psammophilous plant species and communities. These are particularly prominent in the Mediterranean Basin, renowned for its highly specialized and unique flora but recognized as one of the areas that is globally most severely affected by marine litter. To provide a comprehensive picture and outline possible future directions, data on beach litter in the Mediterranean coastal ecosystems were collected through a bibliographic research. Overall, 103 studies investigated the presence of beach litter on the Mediterranean coasts, of which only 18 considered its relationship with psammophilous plant species and communities. Our research highlights that this topic is rather underexplored in the Mediterranean Basin and the need to develop a standardized protocol for the assessment of beach litter that can be applied consistently across different beaches and countries. Information collected through a standardized protocol might improve the management and conservation strategies for these fragile ecosystems. Full article

Rockslides are one of the most dangerous hazards in mountainous and hilly areas. In this study, a rockslide that occurred on 30 November 2022 in Castrocucco, a district located in the Italian municipality of Maratea (Potenza province) in the Basilicata region, was investigated by using pre- and post-event high-resolution 3D models. The event caused a great social alarm as some infrastructures were affected. The main road to the tourist hub of Maratea was, in fact, destroyed and made inaccessible. Rock debris also affected a beach club and important boat storage for sea excursions to Maratea. This event was investigated by using multiscale and multisensor close-range remote sensing (LiDAR and SfM) to determine rockslide characteristics. The novelty of this work lies in how these data, although not originally acquired for rockslide analysis, have been integrated and utilized in an emergency at an almost inaccessible site. The event was analyzed both through classical geomorphological analysis and through a quantitative comparison of multi-temporal DEMs (DoD) in order to assess (i) all the morphological features involved, (ii) detached volume (approximately 8000 m³), and (iii) the process of redistributing and reworking the landslide deposit in the depositional area. Full article

In the past fifteen years, the contamination of the Italian marine coastal environments by asbestos cement materials (ACMs) represents a known crux mostly reported or denounced by mass media and environmental associations. A recent research reporting compositional and textural data related to ACMs found in the beach deposits of a protected natural reserve (Cape Peloro, Messina, Italy) induced the author to perform new petrographic and textural analyses on the Cape Peloro beach sands, pebbles, cobbles (BSPC), and technofossils (bricks, tails, slab, concrete), associated with the previously studied ACMs, in order to compare the data with those of the ACMs previously reported in the literature. The petrographic investigations allowed the author to determine that beach sands and weakly gravelly sands were characterized by a quartzo–lithic signature, being mainly composed of metamorphic grains of quartz (50–60%) and metamorphic lithics (40–50%, mainly composed of polymineral quartz + microcline, quartz + plagioclase, quartz + biotite, quartz + muscovite grains, and monomineral opaque minerals, plagioclase, k-feldspar, and almandine garnet grains), whereas the pebbles and cobbles were made of acid intrusive (granitoids) and metamorphic rocks (gneiss, augen gneiss prevailing). Pebbles and cobbles made up of porphyroids could derive from the cannibalization of the underlying lower to middle Pleistocene siliciclastic deposits of the Messina Formation. Differently, the gneiss, augen gneiss, and granitoids forming the beach pebbles and cobbles, being present both in the crystalline rocks of the Aspromonte Unit and in the clasts of the SGMF, could originate from both of them. Textural investigations allowed the author to characterize grain size, shape parameters, and roundness in the beach deposits. These were mostly composed of sands and weakly gravelly sands with medium grains. Parameters, such as elongation and flatness, showed higher values in the BSPC than in the technofossils. The shapes of the BSPC were mostly from oblate to equant, whereas the shapes of the technofossils were mostly from bladed to oblate. The main differences depended on the original shape of the technofossils, being mostly platy, and their softer composition. The roundness was from angular to sub-rounded. In the Ionian coast of the Cape Peloro peninsula, the source areas for the well-rounded ACM found on the beach and in the beach deposits could have at least four different origins: (i) Possible landfills widespread since the 1970s in the intensively urbanized coastal areas. (ii) Direct abandonment in the coastal area. (iii) Direct abandonment in the streams. (iv) Activities to counteract the erosion/lack of sediment using non-conforming materials. Considering the diffused damage caused by the coastal erosion affecting most of the Italian coast and the obvious increasing dispersion of the asbestos fibers from the ACMs over time, effectual counter actions to prevent further contamination and guidelines for clean-up efforts are necessary. Full article