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Integrating wave energy devices with coastal structures is a promising solution to reduce the cost of wave energy development along with additional shared benefits. In this study, the performance of a heaving spherical point absorber wave energy converter model in irregular waves is analysed and compared experimentally and numerically. After the fundamental investigation of models in regular waves, it is important to advance the testing in more realistic conditions before the sea trial phase. The investigations are conducted in irregular waves on a 1:30 scale model under two scenarios, (1) model heaving alone and (2) model heaving in a chambered breakwater. Irregular waves are generated based on the JONSWAP spectrum with modified parameters to suit the Indian coastal conditions. Results indicate that the wave energy converter model in the chambered breakwater produces 40.25 % higher power than the model heaving alone in irregular sea conditions. The performance of the model is found to be less compared to that in regular waves. [ABSTRACT FROM AUTHOR]

Extremely rapid rates of rise in level and discharge in a subset of flash floods ('abrupt wave front floods', AWF) are separate hazards from peak level. Such flood events are investigated for Pennine catchments in northern England using both gauged and historical information. Gauged level and flow digital records at 15‐min intervals provide recent data. Historical information for 122 AWF events is extracted from a chronology of flash floods for Britain. Historical AWF events are mapped and found to occur on every major Pennine catchment; catchment descriptors are derived as a basis for assessing catchment vulnerability. We discuss the disputed origin of AWF. Using gauged data, we contrast the rising limb of AWF and 'normal' floods. We investigate time series of historical AWF, noting a puzzling peak in the late 19th century. Current rainfall and river monitoring does not provide a reliable basis for understanding AWF processes or for operational response and we suggest improvements. Similarly, current models for design flood estimation and forecasting do not generate the observed rapid increase in level in AWF floods. [ABSTRACT FROM AUTHOR]

Erosion poses a significant threat to coastal and estuarine environments worldwide and is further exacerbated by anthropogenic activities and increasing coastal hazards. While conventional engineered structures, such as seawalls and revetments, are commonly employed to protect shorelines from wave impact and erosion, they can also cause detrimental environmental effects. By creating/restoring coastal habitats with engineered structures, hybrid living shorelines offer coastal protection and other co-benefits. Using aerial imagery, we studied the rates of shoreline change before and after living shoreline installation, and between living shorelines and adjacent bare shorelines in three estuaries in New South Wales, Australia. Mangroves had established behind most rock fillets and displayed a trend of increasing canopy cover with fillet age. In the first 3 years since installation, the rates of lateral shoreline change reduced from − 0.20, − 0.16, and − 0.10 m/year to − 0.03, − 0.01, and 0.06 m/year in living shorelines in Hunter, Manning, and Richmond Rivers, respectively. However, when compared to control shorelines, the effectiveness in reducing erosion varied among living shorelines with mean effect sizes of 0.04, − 0.28, and 1.74 across the three estuaries. A more positive rate of shoreline change was associated with an increasing percentage of mangrove canopy area and an increasing length of protected shoreline at wide channels. While hybrid mangrove living shorelines are a promising solution for mitigating erosion and creating habitats at an estuary-wide scale, they may also contribute to downdrift erosion, emphasising the importance of considering site-specific hydrogeomorphology and sediment movement when installing living shorelines. [ABSTRACT FROM AUTHOR]

A dual-pontoon WEC-breakwater system is proposed to optimise space utilisation and reduce construction costs by integrating wave energy converters (WECs) with breakwaters. Previous parametric studies on the dimensions and layout of WECs have primarily used potential flow theories, often neglecting the viscous effects in wave–pontoon interactions. In this research, I employ a fully nonlinear viscous model, OpenFOAM®, to address these limitations. I examine multiple parameters, including the gap width between the pontoons, the draft, and the structure breadth, to assess their impact on the functional performance of this hybrid system. Furthermore, I discuss the accurate hydrodynamic performance of waves interacting with multiple floating structures and explore how various parameters influence the dual-pontoon WEC-breakwater integrated system's functionality. I discuss a novel analysis of the effective frequency bandwidth, considering both wave energy conversion efficiency and wave attenuation efficiency, to reflect the overall performance of the integrated system. This paper investigates wave–structure interactions and suggests optimisation strategies for the WEC-breakwater integrated system. [ABSTRACT FROM AUTHOR]

In response to the incident of tourists falling into the sea due to waves on the seawall berm at Macau Road, Qingdao, during the passage of Typhoon "Songda" in 2022, a combination of numerical simulations and physical model experiments was performed to investigate the mechanics of the event, with emphasis on the wave flow characteristics and the flow evolution process on the seawall berm as well as the force exerted on a human body-equivalent cylinder model. The study found that the thickness of the return flow was significantly greater than that of the overtopping flow on the landward part of the berm. The recoil forces applied to the model on the berm were larger than the impact forces, and the ratio tended towards 1 as the wave height increased. In addition, the stability of pedestrians on the seawall berm was analyzed. The instability conditions for pedestrians in cross-wave flows differed slightly from those in floods. [ABSTRACT FROM AUTHOR]

In the South Carolina Lowcountry, near‐annual hurricanes and record‐breaking sea levels have led to disastrous flooding, overwhelming the region's historical tidal infrastructures and entrenched racial geographies. In response, Lowcountry governments, institutions, and residents have undertaken efforts at "perimeter protection," raising dikes and seawalls to safeguard selected urban and rural plantation spaces from tidal flooding. Although perimeter protection is presented as a neutral resilience strategy, its practices and material forms reveal a close relationship between coastal protection and efforts to preserve landscapes of white supremacy. Such logics of perimeter protection contrast with everyday affective encounters with eroding coastlines and with the futures outside of bounded edges imagined by Black Charlestonians. By situating the region's hydrological history within the legacy of slavery and plantation extraction, and by following the effects of current sea level rise, we can see how historical hydrologies—which in this case are also racial hydrologies—are entangled with landscapes of contemporary environmental injustice. [ABSTRACT FROM AUTHOR]

This study examines the stress characteristics and deformation modes of masonry walls under flood loads in a 500kV substation project in Xinyang City, Henan Province. A simplified finite element model of substation masonry walls is developed in ABAQUS, considering dynamic water loads, the stress characteristics and deformation modes of masonry walls under flood loads are studied. Flood depth, water velocity, and erosion depth are selected as variables to carry out the parametric analysis of masonry enclosure walls under flood load, to investigate the dynamic response of walls under various parameters, and to examine the damage mechanism of the wall. The research findings suggest that stress levels are elevated at critical locations, such as the bottom center of the wall, the junction between the inner wall and structural column, and the connection between the foundation and structural column during flood loading. The safety of a masonry wall is significantly compromised when flood depth exceeds 0.8 m, water velocity exceeds 2.3 m/s, or erosion depth reaches 0.4 m. A proposed measure aims to enhance the performance of masonry walls by improving stress distribution and reducing stress concentrations, thereby significantly augmenting their load-bearing capacity. [ABSTRACT FROM AUTHOR]

Many structures such as buildings, power plants, stacks, sea walls, bunkers, and tanks are built with reinforced concrete; and durability is a major concern. Corrosion of reinforcement is the most important process of deterioration. Reinforcement corrosion is prevented by maintaining appropriate quality of concrete mix, casting, and curing and by providing the requisite clear cover to reinforcement according to the postulated exposure. The provisions of several international codes were reviewed from these aspects. Many codes can be interpreted in favor of providing different clear covers on different faces of members in a reinforced concrete structure. The authors' interpretation of the Australian and New Zealand codes revealed that these specifically allow the above. However, this practice might lead to severe durability-related concerns, particularly due to corrosion of reinforcement. Case studies conducted with postulated data from a few international codes revealed that internal corrosion cracks might occur earlier than external cracks in certain cases. Internal cracks can be hidden from view and consequently lead to higher damage to the structure prior to detection. For the simultaneous occurrence of corrosion cracks on the internal and external faces of a member, the internal surface chloride concentration would have to be between 18% and 73.2% of the external, with a median of 38%. These could hardly occur in practice—except for treated air facilities. If construction periods are long, this durability issue would be applicable even for treated air facilities. Higher differences in clear cover between internal and external faces, and higher external chloride exposure – both call for larger reduction of chloride exposure from external to internal. Unless the members are designed for corrosion as specified in some (Japanese) codes, the authors advocate the conservative option of using the same cover for all faces of concrete members to achieve a lower life cycle cost of the facility. Practical Applications: Design codes across the world can be interpreted in favor of different clear covers (to reinforcement) on different faces of concrete members according to exposure conditions. Only the Australian and New Zealand codes specifically mention different clear covers for internal and external faces, by the authors' interpretation. This article examines the durability of concrete members with different clear covers on internal and external faces, with case studies generated from a few international codes. The results indicate that in such cases, corrosion cracks might occur on internal surfaces much earlier than the external surfaces. For cracks to occur simultaneously on both surfaces, the internal surface chloride concentration must be as low as 18% of the external, which is difficult to ensure in practice. Early internal cracks could be hidden from view on account of equipment or false ceiling/panels—thereby causing more damage before detection. They would be difficult to detect, to evaluate, and to carry out structural repairs. Therefore, it could be expensive to maintain and could adversely affect the service life of the structure. This study would sensitize the clients, regulators, and engineers to these concerns. The authors suggest that the conservative approach of the same clear cover may be adopted on all faces, according to the worst exposure on any face, to ensure the durability of the concrete structures. [ABSTRACT FROM AUTHOR]

The present work investigates the water wave interaction with bottom-standing thick porous trapezoidal-shaped structures and shore-side vertical rigid wall in the presence of uniform ocean currents. This study has been done to understand the impact of different physical parameters like friction, porosity, and ocean currents along with different structural parameters (width and height) on different phenomena like wave energy reflection, wave forces, wave energy dissipation, etc. The quadratic boundary element method-based numerical technique has been used to solve the boundary value problem. The structural porosity is modeled using Sollitt and Cross's model of water wave interaction with thick porous structures. Several results associated with the wave energy reflection and energy dissipation have been analyzed. Also, the wave force exerted by the incoming waves has been investigated to check the stability and sustainability of the right vertical rigid wall and porous structure. The Doppler-shift effect is observed in wave transformation characteristics due to the presence of ocean currents. The impact of following and opposing ocean currents can be seen in the graph of wave energy reflection, dissipation, and wave forces. The periodic patterns can be observed clearly in wave characteristics like wave energy reflection, dissipation, and wave forces when plotted against the non-dimensional separation gap between the porous breakwater and shore-side rigid seawall. [ABSTRACT FROM AUTHOR]

Breakwaters play an important role in in mitigating wave-induced damage to marine structures. However, conventional submerged breakwaters often exhibit limited wave dissipation capabilities, while floating breakwaters may lack adequate safety performance. Therefore, this study introduces a novel combined breakwater design aimed at addressing the shortcomings of both traditional types. The proposed breakwater integrates a floating structure with a trapezoidal submerged breakwater via an anchor chain connection. To evaluate its efficacy, numerical simulations of wave interactions with structures were conducted using the OpenFOAM computational fluid dynamics (CFD) software in a two-dimensional (2D) numerical flume. Dynamic mesh technology was employed to simulate the motion of the floating body, and the resulting wave loads on a box girder bridge deck positioned behind the breakwater were analyzed to assess the combined breakwater's protective capabilities and influencing factors. Analysis of wave heights and loads on the bridge deck revealed that the combined breakwater outperformed traditional submerged breakwaters in terms of wave dissipation. Furthermore, it was observed that the protective efficacy of the combined breakwater was more sensitive to variations in the size of the floating body compared to the submerged structure, and more responsive to changes in wave period than wave height. Leveraging the ability of the floating body to attenuate waves near the surface and the enhanced impact resistance provided by the combined floating and submerged structures, the proposed breakwater offers a promising approach to improving wave attenuation performance and enhancing safety for coastal infrastructure. [ABSTRACT FROM AUTHOR]

Introduction: The study focuses on evaluating the reliability of prefabricated perimeter walls in substations during flood events. It employs a sophisticated numerical model based on actual engineering data to assess their load-bearing capabilities. The research investigates the impact of crucial flood parameters on the structural behavior of these walls, examines the force transmission mechanisms, and suggests "W-shaped" reinforcement techniques to mitigate stress-related issues. Methods: To meet our research goals, we developed an extensive numerical model for prefabricated perimeter walls, incorporating real-world engineering data. This model enabled us to analyze critical flood parameters, such as flood depth, flow velocity, and flood erosion. Furthermore, we investigated the force transmission mechanisms within the walls and introduced "W-shaped" reinforcement strategies to improve their load-bearing capacity. Results: Our results indicate that flood depth and flow velocity have a substantial impact on the performance of prefabricated perimeter walls, while flood erosion has a minor effect. Safety concerns become prominent when flood depth exceeds 1.0 m or flow velocity surpasses 3 m per second. Analysis of force transmission mechanisms reveals greater displacements at higher water levels. Critical areas, including wall panel-column and wall panel-foundation connections, experience heightened stress levels. Discussion: Our study highlights the significant role of flood depth and flow velocity in evaluating the load-bearing capacity of prefabricated perimeter walls in substation environments. To address potential structural weaknesses, we recommend implementing "W-shaped" wall reinforcement methods, which efficiently decrease both displacement and stress. These findings carry implications for substation design and flood resilience, underscoring the importance of comprehensive flood risk management strategies to protect internal facilities during floods. [ABSTRACT FROM AUTHOR]

Floods can cause masonry buildings to become immersed for a long period of time, which causes the building materials to deteriorate and thus affects the safety performance of the structure. In this study, a long-term-immersed masonry wall was considered as the research object and a cohesive element containing damage evolution was used to simulate the mortar layer, establish a finite-element model of the separated masonry wall and perform numerical loading experiments. Data on crack width variation in the masonry wall was extracted using Python. The effect of a long-termwater-immersion environment on the shear performance of masonry walls was analyzed considering material deterioration. The results show that long-term flooded masonry walls are characterized by low shear capacity and low stiffness and safety reserves cannot be guaranteed. A partially immersed masonry wall is prone to damage from the weak parts and has a high risk coefficient. The macro-damage degree of a masonry wall immersed by a flood is not as serious as that of the original wall in the early stage, but it suddenly increases in the collapse stage and the warning effect of cracks is reduced, which requires special attention in safety assessments. [ABSTRACT FROM AUTHOR]

Settlement prediction based on monitoring data holds significant importance for engineering maintenance of seawalls. In practical engineering, the volume of the collected monitoring data is often limited due to the restrictions of devices and engineering budgets. Previous studies have applied the fractional-order grey model to time series prediction under the situation of limited data volume. However, the performance of the fractional-order grey model is easily affected by the inappropriate settings of fractional order. Also, the model cannot make dynamic predictions due to the characteristic of fixed step size. To solve the above problems, in this paper, the genetic algorithm with enhanced search capabilities was employed to solve the premature convergence problem. Additionally, to solve the problem of the fractional-order grey model associated with fixed step size, the real-time tracing algorithm was introduced to conduct equal-dimensionally recursive calculation. The proposed model was validated using monitoring data of four monitoring points at Haiyan seawall in Zhejiang province, China. The prediction performance of the proposed model was then compared with those of the fractional-order GM(1,1), integer-order GM(1,1), and fractal theory model. Results indicate that the proposed model significantly improves the prediction performance compared to other models. [ABSTRACT FROM AUTHOR]

A 70-day feeding experiment was performed to investigate the effects of dietary vitamin E at different addition levels (0, 100, 200, and 400 mg/kg) on the growth, collagen content, antioxidant capacity, and expressions of genes related to the transforming growth factor beta (TGF-β)/Sma- and Mad-related protein (SMAD) signaling pathway in sea cucumbers (Apostichopus japonicus). The results showed that the A. japonicus in the group with 200 mg/kg vitamin E exhibited significantly higher growth rates, hydroxyproline (Hyp) and type III collagen contents, and superoxide dismutase (SOD) activity, as well as the upregulation of genes related to Tenascin, SMAD1, and TGF-β. Additionally, the A. japonicus in the group with 100 mg/kg vitamin E exhibited significantly higher body-wall indexes, denser collagen arrangements, improved texture quality, higher activities of glutathione peroxidase (GSH-Px) and peroxidase (POD), as well as the upregulation of genes related to collagen type I alpha 2 chain (COL1A2), collagen type III alpha 1 chain (COL3A1), and Sp-Smad2/3 (SMAD2/3). In contrast, the A. japonicus in the group with 400 mg/kg vitamin E showed a decrease in the growth rates, reduced Hyp contents, increased type I collagen contents, collagen fiber aggregation and a harder texture, along with the downregulation of genes related to the TGF-β/SMAD signaling pathway. Furthermore, the A. japonicus in the group with 400 mg/kg exhibited oxidative stress, reflected by the lower activities of SOD, GSH-Px, and POD. These results indicated that A. japonicus fed diets with the addition of 100–200 mg/kg vitamin E had improved collagen retention and texture quality by increasing the activities of antioxidant enzymes and the expressions of genes in the TGF-β/SMAD signaling pathway. However, the excessive addition of vitamin E (400 mg/kg) induced oxidative stress, which could increase the collagen degradation and fibrosis and pose a threat to the growth and texture quality of A. japonicus. [ABSTRACT FROM AUTHOR]

The object of research is permeable vertical walls (breakwaters) with different degrees of permeability. This paper reports the results of experimental research into the interaction of gravity waves with models of permeable vertical walls (breakwaters), which were formed from cylindrical piles of circular cross-section. With the help of visual and instrumental studies, the features of interaction of surface gravity waves with permeable vertical walls of different permeability have been identified. The degree of wave transformation by these walls was also determined in the form of reflection, transmission, and dissipation coefficients of wave energy. It was established that with a decrease in the permeability of the vertical wall and an increase in the steepness of the initial wave and a decrease in its period, the height of the reflected wave increased. The pattern of the transmitted wave height had the opposite trend. It was determined that the wave reflection coefficient increased with a decrease in the permeability of the vertical wall and the steepness of the initial wave. The wave transmission coefficient had the opposite trend, namely, it increased with increasing wall permeability and with decreasing steepness of the initial wave. The gravity wave energy dissipation coefficient decreased with increasing vertical wall permeability, but for waves with a significant steepness hi/λ>0.038, a decrease in the wave energy dissipation coefficient was observed for walls with low permeability and the appearance of extreme values of this coefficient. Thus, features in the interaction of surface gravity waves with permeable vertical walls (breakwaters) of different permeability have been researched and the degree of wave transformation by these walls has been determined, which could make it possible to effectively design and operate permeable vertical walls as coastal protection structures. [ABSTRACT FROM AUTHOR]

Increasing coastal development and global warming have resulted in large-scale habitat changes, with artificial coastal structures replacing extensive tracts of natural shores. In Singapore, for example, more than 63% of the natural coastline has been replaced by seawalls. Multiple studies from both temperate and tropical regions have compared species diversity supported by these artificial structures with natural rocky shores. Few, however, have estimated and compared the population size and movement of common intertidal species between these two habitat types. Using mark–recapture techniques, this study investigated: (1) the population size of three common gastropod genera (Nerita spp. Trochus spp. and Turbo spp.) and (2) differences in displacement of Nerita spp. and Trochus spp. two common species found on natural rocky shores and seawalls in Singapore. The results of our mark–recapture surveys indicated that seawalls supported large densities of Nerita spp.—more than 50 times greater than that on adjacent rocky shores. The mark–recapture data also revealed that movement of the gastropod species differed between the two habitats, with individuals on seawalls generally travelling longer distances. [ABSTRACT FROM AUTHOR]

Hydraulic experiments using a wave flume with a wind tunnel at a scale of 1/40 were carried out to investigate the effect of wind on wave overtopping of a vertical seawall. To ascertain the possible effects of wave breaking, incident waves with various wave steepness (0.0102 to 0.0371) and three kinds of wind forcing (0 m/s, 6.84 m/s, 10.04 m/s) were used. The authors found that winds significantly increased the overtopping rate in general, and that there is a clear relationship between the overtopping rate and the wave steepness. Velocity fields obtained from PIV analysis revealed that the onshore winds directly enhanced the transport of overtopping water mass. The influence of the wind on the wave hydrodynamic processes that indirectly have an effect on the overtopping rate (such as the formation of a partially standing wave, breaker location, and breaker type) is also discussed. The perspective of treating wave overtopping as a transport of water mass could provide a novel understanding of complex fluid behavior, which would help to formulate countermeasures against future disasters influenced by intensive wind forcing. [ABSTRACT FROM AUTHOR]

"Deep Blue" is a drama film that explores the dangers of land development on a small island surrounded by dying coral reefs. The film follows the story of a star-crossed love affair between an architect overseeing the development of a luxury hotel and a marine biologist who supports local environmentalists. The film highlights the negative impacts of deforestation, the construction of a golf course, and the vulnerability of the island to environmental disasters. It also emphasizes the importance of preserving the environment and the resistance against the hotel development led by the Rastafarian community. The film's low budget production showcases the challenges faced by filmmakers in disadvantaged societies. Overall, "Deep Blue" serves as a valuable contribution to the environmentalists' cause and raises awareness about similar issues faced by island nations. [Extracted from the article]

The reflection of surface gravity waves by a vertical wall breakwater connected with a thick surface porous layer is analysed under the framework of potential flow theory. The thick surface porous layer is placed within the confined space available between the vertical permeable wall and the impermeable seawall. The analytical investigation is progressed by creating the hidden water chamber beneath the surface porous layer. The Matched Eigenfunction Expansion Method (MEEM) is used based on the continuity of velocity and pressure along with orthogonal mode-coupling relation. The hidden water chamber will be helpful to enhance the trapping of incident wave energy and also to reduce the quantity of construction material. The present study results are well agreed with the results available in the literature when a hidden water chamber is absent. The effect of permeable wall porosity, thick surface layer porosity, angle of wave contact, depth of the surface porous layer, thickness of the permeable wall, and hidden chamber spacing on wave reflection against incident wave properties and breakwater physical properties are studied. A comparative study is performed between three different types of porous breakwaters to investigate the integrity of the proposed breakwater. The minor value of wave reflection and gradual reduction of fluid force experienced by the rigid wall is achieved due to the presence of a surface layer, which maximises the incident wave damping, as most of the wave energy propagates near the free surface. [ABSTRACT FROM AUTHOR]

To analyze the impacts of groins, sandbars, and channels on the three-dimensional features of rip currents, we conducted experimental investigations on the vertical distribution of rip currents under intersecting waves along barred beaches with channels. This study employed ADV flow velocity measurements at two distinct locations: within channel and on a sandbar. The results indicate that in nodal sections within channel and on a sandbar, the rip head region manifests surface flow characteristics, characterized by high velocities near water surface. In a rip neck location, the vertical distribution of rip currents on a sandbar exhibits greater variability, whereas within channel, the distribution is more homogeneous. The vertical distribution of rip currents in nodal sections within channel aligns with the logarithmic distribution law. The vertical distributions of the alongshore velocity of rip currents display a consistent pattern of higher at the top and lower at the bottom. However, this pattern varies slightly depending on the wave period. The presence of groins influences the fluctuation characteristics of the alongshore velocity of rip currents by regulating the nearshore circulation system. This results in the alongshore velocity of rip currents in channel pointing towards the groin. In contrast, the alongshore velocity of rip currents on sandbar, situated farther away from groin, exerts a weaker effect on the alongshore velocity of a rip current. [ABSTRACT FROM AUTHOR]

Despite seawalls becoming ubiquitous coastal features, and having some physical similarities to natural rocky shores, it remains unclear how these urban habitats influence predator–prey interactions. Predators can affect intertidal mobile prey densities through two pathways: (1) successful predation directly influences prey mortality rates, and (2) direct and indirect effects of predation can scare and induce motile prey to seek safer areas. In this study, we investigated whether intertidal predators affect the density of the marine gastropod, Nerita undata, at four seawall sites in Singapore. Using a tethering method that we developed, we monitored the mortality and other evidence of predation (shell state) of tethered N. undata. Field experiments revealed high (22.5%–82.5%) predation potential of N. undata across the four sites, with significantly higher predation risk at lower shore heights and for snails with mixed shell coloration. Observations and analysis of the shell state after 3 days showed that predation on seawalls was primarily by crushing predators such as fish. Other predators of N. undata include predatory snails, with various feeding methods that left behind different predator signatures. Our results add substantially to the limited knowledge on predator–prey interactions on seawalls, particularly for Nerita undata, and suggest that seawall systems are more dynamic than previously thought. This further highlights the role of these artificial structures as important habitats and feeding grounds in urban coastal ecosystems. [ABSTRACT FROM AUTHOR]

The development of floating photovoltaic systems (FPV) for coastal and offshore locations requires a solid understanding of a design's hydrodynamic performance through reliable methods. This study aims to extend insights into the hydrodynamic behavior of a superficial multi-body FPV system in mild and harsh wave conditions through basin tests at scale 1:10, with specific interest in the performance of hinges that interconnect the PV panels. Particular effort is put into correctly scaling the elasticity of the flexible hinges that interconnect the PV modules. Tests of a 5 × 3 FPV matrix are performed, with and without shelter, by external floating breakwater (FBW). The results show that the PV modules move horizontally in the same phase when the wave length exceeds the length of the FPV system, but shorter waves result in relative motions between modules and, for harsh seas, in hinge buckling. Relative motions suggest that axial loads are highest for the hinges that connect the center modules in the system and for normal wave incidence, while shear loads are highest on the outward hinges and for oblique incidence. The FBW reduces hinge loads as it attenuates the high-frequency wave energy that largely drives relative motions between PV modules. [ABSTRACT FROM AUTHOR]

Climate change creates a difficult choice for property owners and governmental officials alike: Should they invest in costly climate adaptation measures or retreat from climate-exposed areas? Either decision is fraught with legal uncertainty, running headfirst into antiquated legal doctrines designed for a more stable world. Climate impacts to the coastline are forcing policymakers to consider four adaptation tools: (1) resisting climate impacts by building sea walls and armoring the shoreline; (2) accommodating those impacts by elevating existing structures; (3) managed retreat such as systematically and preemptively moving people out of harm's way; and (4) reactively moving people to new locations following natural disasters. This final tool of unmanaged retreat has emerged as the default "strategy." However, longstanding property and tort law doctrines--developed when there was a more stable physical environment--are poised to thwart these tools. In this Article, I argue that just as climate change destabilizes the physical environment, legal doctrine is also ripe for destabilization. Using coastal zone adaptation challenges as a touchpoint, I show how legal doctrines designed for a more stable physical environment constrain climate adaptation efforts. For example, if governments invest in armoring measures, they will confront physical takings jurisprudence that mandates just compensation. The duty to repair and maintain--a mixed question of property and tort law--complicates disinvestment by states and localities from coastal roads and their retreat from coastal areas. Legal doctrine needs to adapt to meet the climate moment. Absent a doctrinal change, climate adaptation will default to unmanaged retreat--an ad hoc, reactive, and disjointed "strategy" that exacerbates existing inequalities. [ABSTRACT FROM AUTHOR]

Over the centuries, the depths of the most severe storm surges that have flooded Venice have been measured using different reference frames, i.e., related to the algae belt (CM), mean sea level (MSL), local land (ZMPS), large-scale leveling (IGM), and satellite altimetry (SA). Some reference frames, i.e., IGM and SA, are absolute, while the others are relative and represent two different physical points of view, i.e., CM and MSL refer to the sea that is rising and ZMPS refers to the land that is subsiding. The perceptions derived from the different systems are contradictory. This paper discusses and compares surges from 1821 to 2021 measured with these frames, also including the commemorative plaques that report the flood depths on walls in Venice. The paper explains the consequences of a change in frame and zero reference, and it transforms the flooding depths from the original systems to make them homogeneous. The severity of flooding changes in terms of rating with the choice of frame. In the 19th century, five storm surges exceeded the famous level of 1966 and, if they were to recur today or in the future, the sea level rise and the local land subsidence that have occurred in the meantime would greatly exacerbate the situation. [ABSTRACT FROM AUTHOR]

In this study, a modified weakly compressible smoothed particle hydrodynamics (WCSPH) mixture model was developed to more accurately simulate the interaction between waves and porous structures. In this model, we enhanced the governing equations of the traditional WCSPH mixture model by introducing Darcy velocity, apparent density, and an adjustable smoothing length. This refinement ensures that the modified model effectively maintains the conservation of fluid volume in seepage simulations. Additionally, this paper proposes a permeable interface treatment technique that replaces traditional smoothed particle hydrodynamics interpolation with finite element shape function interpolation, significantly enhancing computational efficiency. At the same time, we also introduced and revised a particle shifting technique, which further increases the computational precision of the model. The modified WCSPH mixture model was then applied to simulate several physical experiments, including the dam-break wave propagation in a permeable dam, the attenuation of solitary waves on a permeable riverbed, the propagation of the solitary wave on a submerged porous structure, and the breaking process of waves passing through permeable breakwaters. Through comparison with the experimental data and other numerical results, the current model was comprehensively verified from various aspects, such as fluid volume conservation, wave evolution in and around the porous structure, and pressure distribution characteristics. The results confirm the excellent performance of the current model in simulating the interaction between waves and porous structures. [ABSTRACT FROM AUTHOR]

With rising sea level and climate change, coastal protection against natural hazards such as typhoons and storm surges becomes increasingly important in densely populated areas. Yet, how to integrate necessary engineering structures for coastal protection with development of a healthy socio-ecological system represents a realistic question challenging both the science community and practitioners. This study is motivated to examine the role and influence of diverse dimensions in the construction of seawalls for coastal protection and sustainability. Focusing on a case along the Qiantang River in China, we structured an indicator framework based on technical standards and literature for guiding the design and construction of ecological seawalls. We explored and illustrated the application of a multi-criteria decision making (MCDM) method to analyze proposed indicators as design factors and their influence in practice as reflected by expert evaluation. Our empirical analysis revealed a heterogeneous role and influence of different indicators and their asymmetric interaction in seawall construction aimed to deliver structural safety, ecological functions and social development. This study provides important insights into the design and management of seawalls as an integrated, nature-based solution for coastal protection and sustainability, informing practice improvement and contributing to the literature. [ABSTRACT FROM AUTHOR]

Natural shorelines provide ecosystem services that are integral to maintaining healthy and resilient coastal ecosystems and communities. However, anthropogenic and environmental stressors are reducing the extent of natural shorelines, and thus, their capacity to provide critical ecosystem services. Unfortunately, the most common shoreline management strategies involve hardened structures (e.g., bulkheads and seawalls) that are known to impair coastal ecosystems. Living shorelines offer a more environmentally friendly alternative to this shoreline hardening. To increase the adoption of living shorelines, the Mississippi-Alabama Sea Grant Consortium and Florida Sea Grant have produced guidance documents, offered technical assistance, constructed demonstration sites, and hosted trainings for property owners, contractors, and other practitioners. This article summarizes those efforts, details the results that have been achieved, and outlines existing barriers to further living shoreline implementation in the region. [ABSTRACT FROM AUTHOR]

Coastal fishing communities depend on marine resources for their protein and livelihood needs, making them vulnerable to natural hazards. We assessed the exposure and adaptive capacity of six fishing villages located in three municipalities (Cortes, Lianga, Lanuza) in Surigao del Sur, Philippines by determining their resilience to various climatic hazards. We held six focus groups with 10–15 participants from each fishing community (N = 80 participants). We also conducted stakeholder meetings (N = 100 participants) to validate our findings. We used 12 indicators, divided into three components of resilience scored using a Likert scale: preparedness, coping, and adaptive capacity. We identified the important roles of good communication between community and municipality leaders, seminars and training on natural hazard awareness, livelihood alternatives, the presence of marine protected areas, and infrastructure to mitigate the impact of natural hazards (e.g., regular typhoons) such as sea walls. [ABSTRACT FROM AUTHOR]

California and most other coastlines around the world are being impacted by both long-term sea-level rise and short-term extreme events. Due to California's long and intensively developed coastline, it is an important area for evaluating responses to these challenges. The predominant historic approach to coastal erosion in California and globally has been the construction of hard coastal armoring such as seawalls and rock revetments. The concept of living shorelines—defined as using natural elements like plants, sand, or rocks to stabilize the coastline—has been widely proposed as a soft or green response to coastal erosion and flooding. However, these approaches have very limited application in high-energy environments such as California's 1100-mile-long outer coast and are not realistic solutions for protection from wave attack at high tides or long-term sea-level rise. Each of the state's coastal communities need to identify their most vulnerable areas, develop adaptation plans, and plan eventual relocation strategies in response to an accelerating sea-level rise. [ABSTRACT FROM AUTHOR]

The present paper focuses on investigating the cost-effective configuration of an array of wave energy converters (WECs) composed of vertical cylinders situated in front of a vertical seawall in irregular waves. First, the hydrodynamic calculations are performed using a WAMIT commercial code based on linear potential theory, where the influence of the vertical wall is incorporated using the method of image. The viscous damping experienced by the oscillating cylinder is considered through CFD simulations of a free decay test. A variety of parameters, including WEC diameter, number of WECs, and the spacing between them, are considered to determine an economically efficient WEC configuration. The design of the WEC configuration is aided by a cost indicator, defined as the ratio of the total submerged volume of the WEC to overall power capture. The cost-effective configuration of WECs is achieved when WECs are positioned in front of a vertical wall and the distance between them is kept short. It can be explained that the trapped waves formed between adjacent WECs as well as the standing waves in front of a seawall significantly intensify wave fields around WECs and consequently amplify the heave motion of each WEC. A cost-effective design strategy of WEC deployment enhances the wave energy greatly and, consequently, contributes to constructing the wave energy farm. [ABSTRACT FROM AUTHOR]

The main objective of this work was to characterize the acid‐soluble collagen (ASC) and pepsin‐soluble collagen (PSC) from the body wall of the sea cucumber scientifically called, Stichopus hermanni. For the extraction of ASC and PSC, the pre‐treated sea cucumber body walls were subjected to 0.5 M acetic acid and 5 g L−1 pepsin, respectively. The yield of ASC (7.30% ± 0.30%) was found to be lower than the PSC (23.66% ± 0.15%), despite both ASC and PSC having similar chemical compositions except for the quantity of protein. The collagens produced from ASC and PSC show maximum peaks on ultraviolet–visible spectroscopic profiles at wavelengths of 230 and 235 nm, respectively, with no significant difference in the maximum temperature (Tmax) of the extracted ASC and PSC. The ASC's coloration was whiter than that of the PSC. As a result, the collagen obtained from the body wall of the sea cucumber showed promise for usage as a substitute for collagen derived from marine sources. Practical Application: The two most popular methods of collagen extraction were acid hydrolysis and enzymatic hydrolysis. To determine whether the extracted collagen is a suitable substitute for animal collagen in different industries, it is required to characterize its physicochemical qualities. This study discovered a new application for marine collagen in the food industry: The sea cucumber has collagen with a greater yield in pepsin extraction with good physicochemical qualities. [ABSTRACT FROM AUTHOR]

Coastal erosion has increasingly become a problem in recent years due to rising sea levels caused by global warming. To prevent further coastal erosion and damage, control structures like seawalls and breakwaters have been installed along vulnerable coastlines. However, it is crucial that these structures are regularly and thoroughly inspected for any abnormalities or deformations. At present, inspections are done manually by visual surveys which are time-consuming and inefficient. There is great potential to optimize this process using drone technology equipped with 3D laser scanners. In this study, we utilized a drone with a green laser scanner to inspect and diagnose control structures along the coast. We conducted surveys to determine the basic performance of this approach and used ICP algorithms to extract any deformations in vanishing wave blocks over two time periods. Our results showed high variability in basic performance due to the influence of waves during the surveys. However, we were still able to detect strain of around 50 cm in a submerged breakwater located 3 meters below the water's surface. Furthermore, an overall settlement of approximately 34 cm was observed in the vanishing wave blocks along with some localized movements. This demonstrates that drones can be successfully implemented for efficient inspection, diagnosis and detection of abnormalities and deformations in coastal structures that are extremely difficult to identify through visual surveys alone. The use of this advanced technology will allow for quicker identification of at-risk structures, enabling timely maintenance and prevention of further coastal erosion. [ABSTRACT FROM AUTHOR]

Floating breakwaters have been widely developed and researched to reduce wave energy experimentally and in numerical models. One aspect that is quite important in designing a floating breakwater is its layout because it will determine the transmission and the reflection of waves so that it can optimally protect the area behind it. In this research, the effect of wave transmission and reflection is studied numerically with Flow-3D on layout-I, layout-V, and layoutU of floating breakwater models. This series of models is connected with connectors so that the modules are not rigid and can move horizontally and vertically. The model simulation results show that layout-I has good wave reduction capabilities if the incident wave angle is perpendicular to the structure. However, if the wave's angle of incidence is slanted, the ability to reduce the wave is reduced. When viewed from all angles of the incident wave, the U-layout can reduce waves effectively and efficiently. During high tide conditions, the floating breakwater will work optimally in reducing wave energy and reflecting waves. However, the structure's ability to reduce and reflect waves will decrease when seawater recedes. The mooring lines become loose at low tide, so the structure quickly changes position. The impact is that the floating breakwater structure is prone to moving quickly, so incoming waves will receive additional wave propagation energy due to the movement of the structure. [ABSTRACT FROM AUTHOR]

The safety of pedestrians on a breakwater structure or seawall is significantly influenced by two essential factors: the wave overtopping flow velocity (OFV) and the overtopping layer thickness (OLT). The main issue, however, is that most studies have predominantly focused on impermeable structures rather than composite breakwaters. This study conducted 55 physical experiments to investigate the OFV and OLT on a composite breakwater. The non-intrusive bubble image velocimetry (BIV) technique was employed to measure the OFV and OLT, as well as the plunging distance on the rear side of the structure. Empirical equations with two sets of dimensionless variables, the wave steepness and relative crest freeboard, were proposed as predictors. The results show that these two dimensionless variables perform well for both OFV and OLT estimation. The comparison between the proposed empirical equation and the available empirical equation in the literature is also presented. Finally, the proposed empirical equations were used to estimate the maximum instantaneous wave overtopping discharge and plunging distance. The findings of this research offer insights into the physical mechanisms of wave overtopping, providing an initial exploration into the design of composite breakwaters. [ABSTRACT FROM AUTHOR]

The long-term deformation characteristics and damage degree of soft marine-deposited clay must be evaluated to safely design seawalls. According to abundant field evidence, soft marine-deposited clay tends to experience coupled dynamic loading and seepage loading. Determining the critical load and damage index for these complex loading conditions is imperative. With Tianjin marine-deposited clay as an example, we employed an improved cyclic triaxial instrument to analyse the cumulative plastic strain, water discharge and stress–strain relationship of the clay to understand its long-term deformation development. Based on shakedown theory, the critical cyclic stress ratio (CSR) was determined. A multi-factor damage variable method was proposed to evaluate the damage degree. Its comparison with a traditional mono-factor damage variable method illustrated that this method is effective for damage analyses of marine clay around seawalls under coupled dynamic-seepage loading. [ABSTRACT FROM AUTHOR]

Wave propagation, a phenomenon involving the transfer of energy over time, is a significant area of study, particularly with respect to sea waves. Due to their unique geometrical properties and inhomogeneous minimum amplitude, sea waves pose distinct challenges for numerical solutions. This research focuses on the analysis of wave stability against various water velocities and breakwater distances from the coastline. The study employs a hybrid approach, utilizing the Finite Element Method (FEM) to determine the movement of fluid elements through a porous, submerged breakwater. The concept of permeability in breakwaters is integral to this analysis. Permeable breakwaters permit a certain proportion of seawater or wave water to pass through, while absorbing or reflecting the remaining component of the waves. Understanding the permeability of breakwaters can enhance the design effectiveness and efficiency, whilst providing insight into potential impacts on coastal ecosystems. The results of the study demonstrate that the distance of the breakwater from the incoming wave influences both the amplitude and speed of the wave. Specifically, a greater distance between the wave and the breakwater results in a decrease in wave height, thereby increasing the stability of the simulation. For example, the directional and speed components of the movement at [x, y, t] for the first amplitude [20, 2, 15] was found to be 0.12515m, the second amplitude [15, 2, 15] 0.13161m, and the third amplitude [10, 2, 15] 0.13097m. This demonstrates that the breakwater's distance significantly influences wave stability, an important factor to consider in future breakwater design and implementation. [ABSTRACT FROM AUTHOR]

The hydrodynamic characteristics of fixed floating structure (FFSs) of various configurations, such as rectangular fixed floating structures and trapezoidal fixed floating structures coupled with submerged breakwaters of two different shapes, namely, rectangular breakwater and trapezoidal breakwater, are investigated using the multidomain boundary element method under the framework of small-amplitude wave theory. The hydrodynamic analysis of the FFS with and without the presence of submerged breakwater is performed for the variation in physical parameters such as a change in structural parameters of the submerged breakwater (shape, relative submergence depth, relative crest width, and structural porosity), structural parameters of FFS (shape and structural width), wave parameter (angle of incidence), and relative spacing between the FFS and submerged breakwater. The study demonstrates, for a given range of incident wave angles, periodic values of the distance between the submerged breakwater and the FFS and optimal shape combinations for which the coupled structures act effectively in attenuating wave force acting on the FFS and optimizing wave transformations. In addition, to enhance the hydrodynamic performance, the presence of reef structures in front of the FFS is associated, which results in Bragg's resonance with a phase shift in peaks of wave reflection and transmission coefficient caused by changing the structural porosity of the submerged breakwater, indicating that the proposed models are more flexible, allowing demand-based control over shore dynamics and coastal management. The study will be useful for coastal management and safeguarding floating structures by selecting various forms and combinations of coupled FFSs with submerged porous breakwaters. [ABSTRACT FROM AUTHOR]

Floating breakwaters have recently been generating increasing interest as a vital means to provide shelter and protect the ever-increasing number of structures deployed at sea. Notwithstanding the novel ideas being put forward, to date, floating breakwater deployment has been limited to inshore and shallow water areas. The scale of such structures has been restricted to the smaller spectrum. Furthermore, whilst some concepts to integrate floating breakwaters with other offshore systems have been proposed to benefit from cost-sharing strategies, studies related to floating breakwaters integrating energy storage are lacking in the open literature. The present research investigates the wave attenuating and dynamic performance of a large-scale floating breakwater in deep seas with a hydro-pneumatic energy storage system also integrated within the structure. This article highlights the arising need for floating breakwaters and sheds light on the present-day technological status of floating wave breakers. It then lays the ground for the proposed, novel floating breakwater concept that aims to address the current knowledge gaps in this field of study. The simulation results generated from numerical modelling via the potential flow solver ANSYS® AQWA™ have been promising, connoting that the addition of hydro-pneumatic energy storage to a floating breakwater will not lead to a degradation in the dynamic performance or wave breaking efficiency of the floating structure. [ABSTRACT FROM AUTHOR]

The vulnerability to coastal disasters resulting from storm surges and wave overtopping (WOT) during typhoon intrusions is significantly escalating due to rising sea levels. In particular, coastal seawalls constructed along the coast through engineered assessments are experiencing an increase in the frequency of WOT and associated flooding in proportion to the reduction in freeboard due to rising sea levels. This study employed a unified modeling system that combines an empirical formula for estimating WOT volumes with a numerical model simulating tides, waves, and storm surges. The analysis was conducted across the Northwest Pacific (NWP) Ocean, encompassing coastal seawalls and terrestrial regions, using an integrated seamless grid system, which utilized ADCIRC + SWAN + EurOtop, for the present day, 2050, 2070, and 2100 to investigate how vulnerability to WOT changes with sea level rise. The maximum envelope of WOT inundation results for three historical and two 100-year return period synthetic typhoons confirms that vulnerability to WOT intensifies with rising sea levels. The single-process integrated model applied in this study can serve not only for long-term coastal seawall protection design but also for the short-term early warning system for storm surges and WOT, contributing to immediate preparedness efforts. [ABSTRACT FROM AUTHOR]

The purpose of the present study is to reduce the high wave load on a sea wall by utilizing an elastic plate (EP) kept at fixed distance from a porous structure (PS). Thin plate theory is used to model the flow past EP, while Sollit and Cross theory is used to model the flow past PS. A linear potential theory-based analytical solution to the current problem is developed using the eigenfunction expansion technique. To understand the effect of PS and EP in creating tranquility zone and minimum wave loads on the rigid wall, horizontal wave force on the wall, reflection coefficient, dissipation coefficient, and free surface elevation are computed and analyzed for different values of width and friction factor of PS, flexural rigidity and length of EP, angle of incidence, and distance between PS and EP, and the distance between EP and rigid wall. The study demonstrates that both structures considerably reduce the stress on the rigid wall and the wave reflection. It is found that the force on the wall shifted to the left as the width and frictional factor of PS increased. Furthermore, it is observed that PS effectively minimizes the free surface elevation in the region between EP and the wall. It is also found that an effective tranquility zone may be produced, which will put less wave force on the rigid wall, with sufficient spacing between PS and EP, and EP and the wall. The given model is expected to assist in preserving various coastal assets significantly. [ABSTRACT FROM AUTHOR]