Search Results (1,028)

Climate change is driving regime shifts across ecosystems, exposing species to novel challenges of extreme weather, altered disturbances, food web disruptions, and habitat loss. For disturbance-dependent species like the endangered piping plover (Charadrius melodus), these shifts present both opportunities and risks. While most piping plover populations show net growth following storm-driven habitat creation, similar gains have not been documented in the Eastern Canadian breeding unit. In September 2022, post-tropical cyclone Fiona caused record coastal changes in this region, prompting our study of population and nesting responses within the central subunit of Prince Edward Island (PEI). Using satellite imagery and machine learning tools, we mapped storm-induced change in open sand habitat on PEI and compared nest outcomes across habitat conditions from 2020 to 2023. Open sand areas increased by 9–12 months post-storm, primarily through landward beach expansion. However, the following breeding season showed no change in abundance, minimal use of new habitats, and mixed nest success. Across study years, backshore zones, pure sand habitats, and sandspits/sandbars had lower apparent nest success, while washover zones, sparsely vegetated areas, and wider beaches had higher success. Following PTC Fiona, nest success on terminal spits declined sharply, dropping from 45–55% of nests hatched in pre-storm years to just 5%, partly due to increased flooding. This suggests reduced suitability, possibly from storm-induced changes to beach elevation or slope. Further analyses incorporating geomorphological and ecological data are needed to determine whether the availability of suitable habitat is limiting population growth. These findings highlight the importance of conserving and replicating critical habitat features to support piping plover recovery in vulnerable areas. Full article

A surface water extent downscaling framework was developed in the past using a floodability index based on topography. We presented here a new downscaling approach including several improvements. (1) The use of a new Floodability Index (FI), including better integration of auxiliary permanent waters (i.e., presence of water during the whole time record). By using this updated FI, the new downscaling became a true data-fusion with permanent water databases originating mainly from visible observations. (2) Some discontinuities between low resolution cells have been reduced thanks to a new smoothing algorithm. (3) Finally, a coastal extrapolation scheme has been presented to deal with coarse resolution data contaminated by the ocean. This new and complex downscaling framework was tested here on the GIEMS (Global Inundation Extent from Multi-Satellite) database but the approach is generalizable and any surface water database could be used instead. It was shown that this new downscaling procedure (including several processing steps, algorithms and data sources) is a significant improvement compared to the previous version thanks to the new floodability index and the downscaling processing chain. Compared to the previous version, the downscaling results (GIEMS-D) were more coherent with the permanent water database and preserved better the original low-resolution information (e.g., mean scare error water fraction (0–1) of 0.0041 for the old version, and 0.0018 for the new version, over flooded areas in the Amazon). GIEMS-D has also been evaluated at the global scale and over the Amazon basin using independent datasets, showing an overall good performance of the downscaling. Full article

This study addresses the urgent need to move the construction sector toward carbon neutrality and climate resilience, by considering the increasingly intense impacts of climate change. The research aims to evaluate the application of advanced digital prototyping tools and regenerative design principles to identify environmental risks at different scales, with a particular focus on cultural and natural heritage. The hypothesis is that the integration of climate data and predictive models with regenerative design can overcome existing barriers to sustainable practices and significantly enhance the adaptive capacity of the built environment, particularly in safeguarding cultural and natural heritage against the multi-hazard impacts of climate change. To test this hypothesis, an experimental study is conducted using a combination of climate data, advanced modeling and regenerative design tools to assess and manage multi-hazard impacts on cultural and natural heritage. Two case studies were analyzed: Palizzi Marina, a coastal town vulnerable to sea level rise and flooding, and Palazzo Mesiani in Bova, a historic building exposed to increased solar radiation and temperatures. This type of analysis has enabled a comprehensive multi-scenario and multi-hazard assessment that offers a detailed overview of the risks to be considered in the design phase. In conclusion, the research underscores the importance of interdisciplinary approaches and emerging technologies in resilient design frameworks. By integrating climate data and predictive models with regenerative design methodologies, this study can significantly contribute to enhancing the adaptive capacity of the built environment. This approach aids in the transition of the construction sector toward sustainability and climate resilience, particularly in protecting cultural and natural heritage. 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

Shoreline configurations are a complex outcome of the dynamic interplay between natural forces and human actions. This interaction shapes unique coastal morphologies and affects sediment transport and erosion patterns along the coastline. Meanwhile, ephemeral river systems play a vital role in shaping coastlines and maintaining ecosystem sustainability, especially in island settings. In this context, the present study seeks to develop a holistic approach that views coast and watershed systems as a continuum, aiming to investigate their relationships in an island environment, while accounting for human interventions in the river regime. For this task, the empirical USLE method was employed to quantify sediment production and transport from the catchment area to the coast, while hydraulic simulations using HEC-RAS were conducted to assess sediment retention within flood-affected areas. Moreover, coastal vulnerability to erosion was evaluated by applying the InVEST CVI model in order to identify areas at risk from environmental threats. The coastal zone of Petra–Molyvos, Lesvos, Greece, was selected as the study area due to ongoing erosion issues, with particular emphasis on its interaction with the Petra stream as a result of significant human intervention at its mouth. According to the study’s findings, the examined coastal zone is highly vulnerable to combined erosion from wind and waves, while the river’s mouth receives only a small amount of sediment from water fluxes. Evidently, this leads to an increase in beach retreat phenomena, while highlighting the necessity for integrated coastal–watershed management. Full article

Demak is highly vulnerable to flooding from both fluvial and coastal storms, facing increasing pressures on its sustainability and resilience due to multiple compounding flood hazards. This study assesses the inundation hazards in Demak coastal areas by modeling the impacts of compound flooding. We modeled eight scenarios incorporating long-term forces, such as sea level rise (SLR) and land subsidence (LS), as well as immediate forces, like storm surges, wind waves, and river discharge. Our findings reveal that immediate forces primarily increase inundation depth, while long-term forces expand the inundation area. Combined effects from storm tides and other factors resulted in a 10–20% increase in flood extent compared to individual forces. Fluvial flooding mostly impacts areas near river outlets, but the combination of river discharge and storm tides produces flood extents similar to those caused by SLR. Land subsidence emerged as the primary driver of coastal flooding, while other factors, adding just 25% to area increase, significantly impacted inundation depth. These findings underscore the effectiveness of mangroves in mitigating floods in low-lying areas against immediate forces. However, the resilience and sustainability of the Demak region are challenged by SLR, LS, and the need to integrate these factors into a comprehensive flood mitigation strategy. Full article

A multiscale model is proposed to assess the impact of wave loading on coastal or inland bridges. The formulation integrates various scales to examine the effects of flooding actions on fluid and structural systems, transitioning from global to local representation scales. The fluid flow was modeled using a turbulent two-phase level set formulation, while the structural system employed the 3D solid mechanics theory. Coupling between subsystems was addressed through an FSI formulation using the ALE moving mesh methodology. The proposed model’s validity was confirmed through comparisons with numerical and experimental data from the literature. A parametric study was conducted on wave load characteristics associated with typical flood or tsunami scenarios. This included verifying the wave load formulas from existing codes or refined formulations found in the literature, along with assessing the dynamic amplification’s effects on key bridge design variables and the worst loading cases involving bridge uplift and horizontal forces comparable to those typically used in seismic actions. Furthermore, a parametric study was undertaken to examine fluid flow and bridge characteristics, such as bridge elevation, speed, inundation ratio, and bearing system typology. The proposed study aims to identify the worst-case scenarios for bridge deck vulnerability. Full article

Traditional coastal flood risk prediction often overlooks critical geographic features, underscoring the need for accurate risk prediction in coastal cities to ensure resilience. This study enhances the prediction of coastal flood occurrence by utilizing the Geospatial Artificial Intelligence (GeoAI) approach. This approach employed models—random forest (RF), k-nearest neighbor (kNN), and artificial neural networks (ANN)—and compared them to the IPCC risk framework. This study used El Salvador as a demonstration case. The models incorporated seven input variables: extreme sea level, coastline proximity, elevation, slope, mangrove distance, population, and settlement type. With a recall score of 0.67 and precision of 0.86, the RF model outperformed the other models and the IPCC approach, which could avoid imbalanced datasets and standard scaler issues. The RF model improved the reliability of flood risk assessments by reducing false negatives. Based on the RF model output, scenario analysis predicted a significant increase in flood occurrences by 2100, mainly under RCP8.5 with SSP5. The study also highlights that the continuous mangrove along the coastline will reduce coastal flood occurrences. The GeoAI approach results suggest its potential for coastal flood risk management, emphasizing the need to integrate natural defenses, such as mangroves, for coastal resilience. Full article

This research analyses beach vulnerability to erosion along the coast of Valencia province, Spain. The Coastal Vulnerability Index (CVI) is used to assess vulnerability, considering the following variables: beach width, beach erosion/accretion rate, dune width, wave height, relative coastal flood level, submerged vegetation, upper depth limit of submerged vegetation, and percentage of vegetated dune. The results show that vulnerability varies significantly along the coast. The vulnerability assessment revealed that 26.9% of the coastal sections were classified as having very low susceptibility to erosion, 34.5% as low, 22.3% as moderate, 12% as high, and 4.3% as very high. Urbanized areas with reduced dunes are more vulnerable than natural areas with wide beaches and well-developed dunes. The study highlights and discusses limitations of the CVI method and suggests using the mean instead of the square root to calculate the overall vulnerability index due to the influence of one single variable in this formula. It is concluded that natural areas characterized by the presence of dunes exhibit a diminished vulnerability to erosion when compared to highly urbanized regions devoid of dunes and marine vegetation. Full article

Understanding the salinity transport process around the sediment–water interface is important for water resources management in the upper reach of an estuary. In this study, we developed a baroclinic fluid dynamic model for investigating the flow and salt transport characteristics within the sediment–water interface under tidal forcing. The validation showed robust model performance on the salinity transport within the sediment–water interface. The results revealed that the turbulent kinetic energy, dissipation rate, and kinetic energy production rate exhibited periodic variations within the seabed boundary layer. The thickness of the viscous sublayer and the mean flow showed an inverse relationship. Water and salinity exchange within the sediment–water interface occurred predominantly via turbulent diffusion, with extreme turbulent kinetic energy production rates appearing during the tidal reversal, flood, and ebb stages. The sediment acted as a source of salinity release during ebb tides and a sink for salinity absorption during flood tides. As the sediment depth increased, fluctuations in salinity were weakened. These results clearly illustrated that the sediment layer is important in modulating the salinity transport in the upper reach of an estuary. However, such an important process was usually excluded by previous studies. The model developed in this study can be used as a sediment–water interface module that, coupled with other hydrodynamic models, can evaluate the contributions of the sediment layer to the salinity exchange in coastal water. Full article

Most river deltas worldwide are located in well-developed, densely populated lowland regions that face challenges from accelerated sea level rise. Deltas with morphological equilibrium are the foundation for associated prosperous economies and societies, as well as for preserving ecological fragile environments. And for deltas to be in morphological equilibrium, sufficient fluvial sediment supplies are fundamental. Severe droughts have significant impacts on the sediment load discharged to the sea, but this is considerably less studied compared to flooding events. This study examines the characteristics of Yangtze River sediment flowing toward the East China Sea during severe droughts. The effect of the Three Gorges Dam (TGD) was investigated by comparing the difference before and after its construction in 2003. Results indicate that the sediment load from the Yangtze River to the sea has experienced a more pronounced decrease during severe drought years since 2003. The primary cause is a substantial reduction in sediment supply from the upper reaches, resulting from the impoundment of the Three Gorges Reservoir created in 2003 and the construction of additional major reservoirs in the upper reach thereafter. Simultaneously, this is accompanied by the fining of sediment grain size. The fining of sediment and considerably reduced sediment load discharged to the sea during severe droughts after 2003 are likely to accelerate the erosion of the Yangtze subaqueous delta. The rating parameter values during severe drought years fall within the range observed in normal years, indicating that these drought events do not align with extreme rating parameter values. Less than 30% of the average discrepancy between measured and reconstructed sediment loads in severe drought years before 2003, and approximately 10% of the discrepancy after 2003, demonstrate the feasibility of reconstructing sediment loads for severe drought events using a sediment rating curve. This rating curve is based on daily water discharge and sediment concentration data collected during the corresponding period. These findings indicate that the rating curve-based reconstruction of sediment load performs well during severe droughts, with relative error slightly exceeding the average error of normal years prior to 2003 and approaching that observed after 2003. This study provides insights on sediment management of the Yangtze River system, including its coastal zone, and is valuable for many other large river systems worldwide. Full article

Climate warming exacerbates the deterioration of soil and degradation of vegetation caused by coastal flooding, impairing ecosystem climate-regulating functions. This will elevate the risk of carbon storage (CS) loss, further intensifying climate change. To delve deeper into this aspect, we aimed to integrate future land use/land cover changes and global mean sea-level rise to assess the impact of coastal floods on terrestrial CS under the effects of climate change. We compared the 10-year (RP10) and 100-year (RP100) return-period floods in 2020 with projected scenarios for 2050 under SSP1-26, SSP2-45, SSP3-70, and SSP5-85. The study findings indicate that CS loss caused by coastal flooding in China’s coastal zones was 198.71 Tg (RP10) and 263.46 Tg (RP100) in 2020. In 2050, under the SSP1-26, SSP2-45, and SSP3-70 scenarios, the CS loss is projected to increase sequentially, underscoring the importance of implementing globally coordinated strategies for mitigating climate change to effectively manage coastal flooding. The value of CS loss is expected to increase in 2050, with an anticipated rise of 97–525% (RP10) and 91–498% (RP100). This highlights the essential need to include coastal flood-induced CS changes in carbon emission management and coastal climate risk assessments. Full article

Constructing a precise and effective evaluation index system is crucial to flood disaster prevention and management in coastal areas. This study takes Lucheng District, Wenzhou City, Zhejiang Province, southeastern China, as a case study and constructs an evaluation index system comprising three criterion levels: disaster-causing factors, disaster-gestation environments, and disaster-bearing bodies. The weights of each evaluation index are determined by combining the Analytic Hierarchy Process (AHP) and the entropy method. The fuzzy matter-element model is utilized to assess the flood disaster risk in Lucheng District quantitatively. By calculating the correlation degree of each evaluation index, the comprehensive index of flood disaster risk for each street area is obtained, and the flood disaster risk of each street area is classified according to the risk level classification criteria. Furthermore, the distribution of flood disaster risks in Lucheng District under different daily precipitation conditions is analyzed. The results indicate that: (1) the study area falls into the medium-risk category, with relatively low flood risks; (2) varying precipitation conditions will affect the flood resilience of each street in Lucheng District, Wenzhou City. The flood disaster evaluation index system and calculation framework constructed in this study provide significant guidance for flood risk assessment in coastal plain cities. Full article

Coastal protection solutions can be categorised as grey, hybrid or natural. Grey infrastructure includes artificial structures like dykes. Natural habitats like seagrasses are considered natural protection infrastructure. Hybrid solutions combine both natural and grey infrastructure. Evidence suggests that grey solutions can negatively impact the environment, while natural habitats prevent flooding without such adverse effects and provide many ecosystem services. New types of protective solutions, called biomimetic solutions, are inspired by natural habitats and reproduce their features using artificial materials. Few studies have been conducted on these new approaches. This study aims to quantify wave dissipation observed in situ above a biomimetic solution inspired by kelps, known for their wave-dampening properties. The solution was deployed in a full water column near Palavas-les-Flots in southern France. A one-month in situ experiment showed that the biomimetic solution dissipates around 10% of total wave energy on average, whatever the meteo-marine conditions. Wave energy dissipation is frequency-dependent: short waves are dissipated, while low-frequency energy increases. An anti-dissipative effect occurs for forcing conditions with frequencies close to the eigen mode linked to the biomimetic solution’s geometry, suggesting that resonance should be considered in designing future biomimetic protection solutions. Full article

Coastal wetlands face threats from climate change-induced flooding and biological invasions. Plants respond to these stressors through changes in their phytochemical metabolome, but it is unclear whether stressors affecting one tissue compartment (e.g., leaves) create vulnerabilities in others (e.g., roots) or elicit similar responses across tissues. Additionally, responses to multiple simultaneous stressors remain poorly understood due to the focus on individual metabolites in past studies. This study aims to elucidate how the phytochemical metabolome of three Phragmites australis (Cav.) lineages, common in the Mississippi River Delta, responds to flooding and infestation by the non-native scale insect Nipponaclerda biwakoensis (Kuwana). Among these lineages, one is non-native and poses a threat to North American wetlands. Results indicate that metabolomic responses are highly specific, varying with lineage, tissue type, stressor type, and the presence of multiple stressors. Notably, the non-native lineage displayed high chemical evenness, while the other two showed stressor-dependent responses. The 10 most informative features identified by a machine learning model showed less than 1% overlap with known metabolites linked to water and herbivory stress, underscoring gaps in our understanding of plant responses to environmental stressors. Our metabolomic approach offers a valuable tool for identifying candidate plant genotypes for wetland restoration. Full article