Coastal Engineering最新文献

{"title":"Wave runup extraction on dissipative beaches: New video-based methods","authors":"Meye J. van der Grinten , Jakob C. Christiaanse , Ad J.H.M. Reniers , Falco Taal , Jens Figlus , José A.A. Antolínez","doi":"10.1016/j.coastaleng.2025.104757","DOIUrl":"10.1016/j.coastaleng.2025.104757","url":null,"abstract":"<div><div>Wave runup observations are important for coastal management providing data to validate predictive models of inundation frequencies and erosion rates, which are vital for assessing the vulnerability of coastal ecosystems and infrastructure. Automated algorithms to extract the instantaneous water line from video imagery struggle under dissipative conditions, where the presence of a seepage face and the lack of contrast between the sand and the swash impede proper extraction, requiring time-intensive data quality control or manual digitization. This study introduces two novel methods, based on color contrast (CC) and machine learning (ML). The CC method combines texture roughness — local entropy — with saturation. Images are first binarized using entropy values and then refined through noise reduction by binarization of the saturation channel. The ML method uses a convolutional neural network (CNN) informed by five channels: the grayscale intensity and its time gradient, the saturation channel, and the entropy and its time gradient. Both methods were validated against nine manually labeled, 80 min video time series. The CC method demonstrated strong agreement with manually digitized water lines (RMSE = 0.12 m, <span><math><mrow><mi>r</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>94</mn></mrow></math></span> for the vertical runup time series; RMSE = 0.08 m, <span><math><mrow><mi>r</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>97</mn></mrow></math></span> for the 2% runup exceedance (<span><math><msub><mrow><mi>R</mi></mrow><mrow><mn>2</mn><mtext>%</mtext></mrow></msub></math></span>); and RMSE = 3.88 s, <span><math><mrow><mi>r</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>70</mn></mrow></math></span> for the mean period (<span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>m</mi><mo>−</mo><mn>1</mn><mo>,</mo><mn>0</mn></mrow></msub></math></span>)). The ML model compared well with the manually labeled time series (RMSE = 0.10 m, <span><math><mrow><mi>r</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>96</mn></mrow></math></span> for the vertical runup time series; RMSE = 0.09 m, <span><math><mrow><mi>r</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>97</mn></mrow></math></span> for <span><math><msub><mrow><mi>R</mi></mrow><mrow><mn>2</mn><mtext>%</mtext></mrow></msub></math></span>; and RMSE = 3.51 s, <span><math><mrow><mi>r</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>79</mn></mrow></math></span> for <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>m</mi><mo>−</mo><mn>1</mn><mo>,</mo><mn>0</mn></mrow></msub></math></span>). Furthermore, the computed <span><math><msub><mrow><mi>R</mi></mrow><mrow><mn>2</mn><mtext>%</mtext></mrow></msub></math></span> values of both methods show a good agreement with the formula proposed by Stockdon et al. (2006) for extremely dissipative conditions, with RMSE-values lower than 0.13 m and correlations exceeding 0.70 for manual, CC, and ML estimates. While the CC method is deemed applicable for wave-by-wave analysis under similar dissipative conditions with ","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"200 ","pages":"Article 104757"},"PeriodicalIF":4.2,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143898454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Laboratory measurements of bed shear stress under spilling and plunging regular waves","authors":"Francis C.K. Ting,&nbsp;Miaad Mojadam,&nbsp;Linet C. Paul","doi":"10.1016/j.coastaleng.2025.104769","DOIUrl":"10.1016/j.coastaleng.2025.104769","url":null,"abstract":"<div><div>The bed shear stress induced by breaking-wave-generated vortices on a plane slope was investigated for spilling and plunging regular waves. Three-component, three-dimensional (3C3D) velocity measurements were conducted from the free surface to the bottom in the inner surf zone using a Volumetric Three-Component Velocimetry (V3V) system. The 3C3D measurements were supplemented by high resolution two-dimensional (2D) velocity measurements inside the bottom boundary layer obtained using a Particle Image Velocimetry (PIV) system. The bed shear stress was determined from the measured velocities in the viscous sublayer using the velocity gradient method. The measured data were used to study the evolution of the large eddies and the characteristics of their induced bed shear stresses. The results showed that, in both spilling and plunging waves, the basic three-dimensional (3D) structure of the large eddies was a coherent vortex loop consisting of two counter-rotating vortices with strong downward momentum. Breaking wave vortices impinged on the bottom under the wave crest in plunging waves and induced large bed shear stress fluctuations when the wave-induced (mean) flow was shoreward, while they reached the bottom later in spilling waves and mainly affected the negative bed shear stresses after flow reversal. When the boundary layer was not disturbed by breaking wave turbulence, the near-bed velocity profile was similar to that observed in non-breaking waves in the laminar/transitional turbulent flow regime. The viscous sublayer and most of the buffer layer were developed by the time of the wave crest and wave trough phases, but a logarithmic region did not always exist. It was found that the instantaneous velocities did not generally conform to a law-of-the-wall profile during vortex impingement and the Spalding wall function underpredicted the bed shear stress in some cases but overpredicted in others. It was also found that the fluid shear stress measured at only a small distance above the bed grossly overestimated the instantaneous bed shear stress, and that a good correlation between the two parameters was observed only when sweep type events occurred in the bed region.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"200 ","pages":"Article 104769"},"PeriodicalIF":4.2,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143931484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Laboratory experiment on the impact of wind on water turbulence in shallow areas","authors":"Peng Yao ,&nbsp;Jinshan Pu ,&nbsp;Yongping Chen ,&nbsp;Min Su ,&nbsp;Marcel J.F. Stive ,&nbsp;Zhengbing Wang","doi":"10.1016/j.coastaleng.2025.104765","DOIUrl":"10.1016/j.coastaleng.2025.104765","url":null,"abstract":"<div><div>A series of laboratory experiments focused on the wind impact on the vertical turbulence structure in shallow water has been carried out. The turbulence characteristics in the mid-lower water column under relatively strong wave conditions are investigated. For different experimental conditions (i.e., waves only, wind only, combinations of wind and waves) in a wind-wave flume, the effects of wind and waves were investigated in detail by decomposing the total energy into different terms (i.e., wind-driven currents, wind waves, wind-induced turbulence). The results show that shallow water waves play a major role in transferring energy by non-zero wave-induced Reynolds stress (<span><math><mrow><mover><mrow><mover><mi>u</mi><mo>˜</mo></mover><mover><mi>w</mi><mo>˜</mo></mover></mrow><mo>‾</mo></mover></mrow></math></span>), turbulent diffusion (<span><math><mrow><mover><mrow><msup><mi>u</mi><mo>′</mo></msup><msup><mi>w</mi><mo>′</mo></msup></mrow><mo>‾</mo></mover></mrow></math></span>). The superimposed wind can further modify the energy transference due to its impact on wave asymmetry and skewness as well as through homogenizing the time-average velocity profiles. Subsequently, the impact of wind on turbulence structure was explored in detail. The most important finding is that the wind can directly influence water turbulent diffusion (<span><math><mrow><mover><mrow><msup><mi>u</mi><mo>′</mo></msup><msup><mi>w</mi><mo>′</mo></msup></mrow><mo>‾</mo></mover></mrow></math></span>) along with wave-induced turbulence. The vertical turbulence intensity (σ_w) is more sensitive to wind than the horizontal turbulence intensity (σ_u). Furthermore, the major way that wind affects water turbulence is by introducing nonlinear wind and wave interactions, which exhibit a maximum effect (∼60 % compared to the respective effect of wind and wave) at the edge of the bottom boundary layer. This study demonstrates that the wind can transfer momentum downward to mid-lower water columns even under strong waves in shallow waters, which differs from that in deep water systems.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"200 ","pages":"Article 104765"},"PeriodicalIF":4.2,"publicationDate":"2025-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143906379","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Equilibrium shoreline change model with non-stationary free parameters at Hasaki Beach, Japan","authors":"Xinyu Chen ,&nbsp;Masayuki Banno ,&nbsp;Nobuhito Mori","doi":"10.1016/j.coastaleng.2025.104761","DOIUrl":"10.1016/j.coastaleng.2025.104761","url":null,"abstract":"<div><div>The ability to accurately predict shoreline response to changing wave conditions is crucial for coastal management, with equilibrium-based shoreline models demonstrating success in forecasting shoreline evolution across various temporal scales. However, the conventional use of time-invariant parameters in these models may limit their capability to capture the full range of beach responses, particularly during extreme events. This study investigates the non-stationary characteristics of free parameters in the equilibrium shoreline model <em>ShoreFor</em> and evaluates alternative wave-forcing variants to enhance model performance. Using a unique, high-frequency dataset of shoreline positions collected at daily to weekly intervals with low measurement uncertainty from 1991 to 2015 at Hasaki Beach, Japan, we implement both stationary and non-stationary parameter approaches. We develop a novel segmentation method where the 20-year calibration period (1991-2010) is divided into monthly segments to capture wave seasonal patterns, with model performance evaluated over a 10-year interval within calibration and a 5-year validation period. Comparative analysis of three wave-forcing variants—significant wave height (<span><math><msub><mrow><mi>H</mi></mrow><mrow><mi>s</mi></mrow></msub></math></span>), dimensionless settling velocity (<span><math><mi>Ω</mi></math></span>), and wave energy (<span><math><mi>P</mi></math></span>)—reveals that <span><math><msub><mrow><mi>H</mi></mrow><mrow><mi>s</mi></mrow></msub></math></span> provides more stable and superior performance at Hasaki Beach compared to the alternatives. Analysis of segment-derived relationships shows highly variable accretion efficiency coefficients (<span><math><msup><mrow><mi>C</mi></mrow><mrow><mi>a</mi></mrow></msup></math></span>) with a weak positive correlation between significant wave height and accretion efficiency, potentially indicating more efficient shoreline restoration during higher wave periods. Notably, these segment-derived parameter relationships maintain their validity when applied to longer continuous simulations, despite being calibrated within discrete temporal windows. The non-stationary model with <span><math><msub><mrow><mi>H</mi></mrow><mrow><mi>s</mi></mrow></msub></math></span> as forcing variant substantially improves model performance during calibration, increasing the correlation coefficient from 0.36 to 0.61, and better captures extreme erosion and accretion events throughout both calibration and validation periods. These findings demonstrate the importance of incorporating time-varying parameters in equilibrium-based models and guide the selection of appropriate wave-forcing variants for improving future shoreline change predictions under changing wave climate.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"200 ","pages":"Article 104761"},"PeriodicalIF":4.2,"publicationDate":"2025-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143890981","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Solitary wave evolution over a 3D submarine topography","authors":"Haocheng Lu,&nbsp;Qian Wang,&nbsp;Changze Zhao,&nbsp;Hua Liu","doi":"10.1016/j.coastaleng.2025.104758","DOIUrl":"10.1016/j.coastaleng.2025.104758","url":null,"abstract":"<div><div>This study provides a comprehensive examination of solitary wave propagation and breaking over a three-dimensional (3D) topography, both experimentally and numerically. The 3D topography, inspired by the Whalin (1971) experiment, is characterized by a sloped circle array with a 0.656 scale ratio. Using wave gauges, Acoustic Doppler Velocimeters (ADV), and imaging equipment, wave elevations, water particle velocities, and wave breaking images were captured, respectively. Numerical simulations utilized the multiphase VOF-based solver <span>interFoam</span> with a realizable <span><math><mi>k</mi></math></span>–<span><math><mi>ɛ</mi></math></span> closure model, enhanced by a customized adaptive refinement strategy. Water particle velocities revealed insights into wave evolution, with experimental findings largely congruent with numerical predictions. Wave breaking dynamics were further explored by comparing experimentally observed and simulated whitecap regions. Energy budget analysis confirmed wave breaking as the dominant mechanism of energy dissipation, with bottom friction playing a minor role. In summary, this research offers a holistic understanding of solitary wave behavior over a 3D topography, bridging experimental observations with numerical simulations.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"200 ","pages":"Article 104758"},"PeriodicalIF":4.2,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143882868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing the role of a probabilistic model for guiding storm surge barrier maintenance","authors":"Sunke Trace-Kleeberg ,&nbsp;Krijn Saman ,&nbsp;Robert Vos ,&nbsp;Elja Huibregtse ,&nbsp;Ivan D. Haigh ,&nbsp;Marc Walraven ,&nbsp;Annette Zijderveld ,&nbsp;Susan Gourvenec","doi":"10.1016/j.coastaleng.2025.104766","DOIUrl":"10.1016/j.coastaleng.2025.104766","url":null,"abstract":"<div><div>Storm surge barriers provide flood protection to many major coastal cities in estuaries around the world. Maintenance of these assets is critical to ensure they remain reliable and continue to comply with national legal protection standards. There are often critical thresholds of environmental conditions, beyond which maintenance work is unsafe to be carried out. However, as storm surge barriers age and with climate change effects such as sea-level rise and possible changes in storminess, periods when environmental conditions exceed set thresholds will occur more frequently, so carrying out the required work in available maintenance windows will become increasingly challenging. Probabilistic models enable the use of ensemble forecasts of upcoming water levels to determine the likelihood of conditions exceeding the threshold and so can inform on decision making regarding maintenance. This paper evaluates a probabilistic model currently in operational use by Rijkswaterstaat, the Dutch Ministry of Infrastructure and Water Management, to guide maintenance decisions at the Maeslant barrier in the Netherlands. Sixteen years of historic highwater level forecasts from a combination of European Centre for Medium-Range Weather Forecasts and Dutch Continental Shelf Model v5 are used with observations from the Hoek van Holland tide gauge to evaluate and sensitivity test the probabilistic model. Binary classification is used to assess the performance of the probabilistic model. Findings show that the model is conservative with 33.1 % of outcomes resulting in a False Alarm. Changing the baseline parameters of critical probability and water level threshold impacts the balance between False Alarm and Miss outcomes. Increasing the critical probability reduces the number of False Alarms but increases the Miss situations, emphasising the trade-off between acceptable risk and time available to carry out maintenance work. This study highlights the delicate balance between model parameter selection and the associated risk with respect to the maintenance of storm surge barriers.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"200 ","pages":"Article 104766"},"PeriodicalIF":4.2,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143924579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A neural network-based surrogate model for efficient probabilistic tsunami inundation assessment","authors":"Yo Fukutani,&nbsp;Makoto Motoki","doi":"10.1016/j.coastaleng.2025.104767","DOIUrl":"10.1016/j.coastaleng.2025.104767","url":null,"abstract":"<div><div>Probabilistic assessment and uncertainty evaluation of the inundation depth and distribution of tsunamis are critical for developing effective tsunami disaster preparedness and mitigation efforts. However, existing approaches based on nonlinear long wave theory, which is commonly used to analyze tsunami propagation and inundation in shallow waters, are computationally expensive, thereby limiting their practical application to probabilistic assessment, which requires numerous simulations. In this study, we propose an innovative method to reduce the analytical burden of probabilistic tsunami inundation assessment by building a surrogate model using deep neural networks (DNNs). Different inputs are tested, including the slip distribution of an earthquake fault, the initial water level distribution, and the water level distribution over time using linear long wave theory. The results show the possibility of predicting the tsunami inundation depths and inundation distributions with some accuracy directly from the slip distributions of earthquake faults rather than from information on initial water levels and subsequent tsunami water levels. These results indicate that, as long as the information on the slip distribution of a fault is available, the tsunami inundation depth and distribution can be instantly predicted using a surrogate model that has appropriately been trained on the outcomes of physical model simulations. This finding may constitute a breakthrough prediction method. If the probabilistic evaluation of the inundation depth and distribution or the evaluation of uncertainty can be easily performed, then local tsunami risk assessment and various disaster countermeasures based on such an assessment can be promoted.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"200 ","pages":"Article 104767"},"PeriodicalIF":4.2,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143890980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modelling the responses of the salt marsh and its adjacent tidal mudflat to the tidal dyke and different supplied sediments in Laizhou Bay, China","authors":"Cheng Chen ,&nbsp;Yuhong Liu ,&nbsp;Yipeng Yao ,&nbsp;Xue Wang ,&nbsp;Jiayuan Liu","doi":"10.1016/j.coastaleng.2025.104760","DOIUrl":"10.1016/j.coastaleng.2025.104760","url":null,"abstract":"<div><div>Intertidal salt marsh degradation due to natural and anthropogenic pressures poses a significant threat to coastal ecosystems. This degradation largely depends on the expansion of salt marsh, and our current understanding and ability to predict how salt marshes respond to varying sediment supplies, especially in relation to tidal dykes, are still limited. This study developed a model by coupling tide movement, plant growth, and sedimentation to simulate the expansion processes of the <em>Suaeda salsa</em> salt marsh and its adjacent tidal mudflat, while also predicting potential future expansion trends. The results revealed that net sediment height was negative in the tidal mudflat but positive in the salt marsh. When suspended matter concentration in tidewater ranged from 10 to 25 g m⁻³, tide mudflat areas would increase and reach a stable maximum, while salt marsh areas would continuously decline. Higher sediment supplies delayed maximum mudflat expansion, suggesting that enhancing sediment availability could mitigate salt marsh loss. However, even with increased sediment, rising sea levels and sediment undersupply over extended periods (decades to centuries) may still result in salt marsh drowning, disappearance, and transformation into tidal mudflats. Our findings highlighted that (i) Pioneer plant survival is crucial for determining salt marsh migration inland or seaward; (ii) Tidal dykes stabilize mudflat areas at the expense of salt marsh loss; (iii) Removing dykes or enhancing sediment supply could help conserve and restore intertidal salt marshes. These insights offer valuable strategies for coastal ecosystem management.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"200 ","pages":"Article 104760"},"PeriodicalIF":4.2,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143879014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental investigation on scour characteristics and predictive model of monopile foundations under breaking waves","authors":"Gang Tao ,&nbsp;Xizeng Zhao ,&nbsp;Yadong Hou ,&nbsp;Zhaoyuan Huang ,&nbsp;Siwen Zhang ,&nbsp;Jintao Lu","doi":"10.1016/j.coastaleng.2025.104764","DOIUrl":"10.1016/j.coastaleng.2025.104764","url":null,"abstract":"<div><div>Breaking waves in nearshore regions induce intense sediment transport, leading to significant scour around offshore wind turbine monopile foundations constructed in shallow water areas, thereby threatening structure stability. Due to the complex flow behavior and soil response involved in monopile scour under breaking waves, the scour characteristics and predictive models have not been adequately investigated. This study systematically analyzes the effects of breaking wave parameters, monopile location, and water depth on scour depth and morphology through wave flume experiments. A three-dimensional laser scanning technique was employed to show the evolution of seabed topography. The results indicate that breaking waves cause extensive seabed morphodynamic changes characterized by forming a bar-trough system, which superimpose onto the local scour process around the monopile. Additionally, the pile location parameter <em>α</em>, defined as the ratio of the distance between the monopile and the breaking point to the wavelength, significantly influences the primary scour mechanism, determining the scour depth and morphology. Specifically, when <em>α</em> ranges from 0.35 to 0.55, the monopile is situated in the region of fully developed turbulence, and the maximum scour depth found was approximately 0.5<em>D</em>. As the breaker type transitions from collapsing to plunging, it can prompt the formation of the bar-trough system. Conversely, increasing water depth generates a water cushion effect, suppressing the formation of the bar-trough system and reducing the monopile scour depth. Finally, an empirical formula of monopile scour depth based on <em>KC</em> number, modified Ursell parameter, and monopile location parameter is proposed, which can effectively predict the scour depth in breaking waves.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"200 ","pages":"Article 104764"},"PeriodicalIF":4.2,"publicationDate":"2025-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143851382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Wave-induced hydrodynamics of biogenic structures in the central Wadden Sea: Implications of the transformation from mussel beds to oyster reefs for wave attenuation","authors":"Jan Hitzegrad ,&nbsp;Lisa Rentsch ,&nbsp;Tom K. Hoffmann ,&nbsp;Maike Paul ,&nbsp;Christian Windt ,&nbsp;Torsten Schlurmann ,&nbsp;Nils Goseberg","doi":"10.1016/j.coastaleng.2025.104763","DOIUrl":"10.1016/j.coastaleng.2025.104763","url":null,"abstract":"<div><div>The transformation of the predominant biogenic structures in the Wadden Sea, from blue mussel (<em>Mytilus edulis</em>) beds to Pacific oyster (<em>Magallana gigas</em>) reefs, has increased their topographical roughness, impacting the wave-biogenic structure interactions. Despite the general knowledge of increased wave attenuation due to the ecological transformation, a detailed quantification of wave energy dissipation induced by both biogenic structures and a comprehensive understanding of the governing processes remain lacking. This study systematically investigates frictional wave energy dissipation of both biogenic structures by subjecting generic surrogate models to regular, non-breaking waves in reduced-scale wave flume experiments. The results reveal pronounced wave height reductions for both structures, with <em>oyster</em> reefs exhibiting approximately twice the frictional wave energy dissipation (wave friction factor <em>f</em>_{<em>w,OR</em>} <em>=</em> 0.44 ± 0.30) of <em>mussel</em> beds (<em>f</em>_{<em>w,MB</em>} = 0.21 ± 0.18). Comparing near-bed velocities with topographical roughness parameters identified mussel agglomerations governing the frictional wave energy dissipation in mussel beds and oyster shells in oyster reefs. In <em>mussel</em> beds, form drag dominates frictional resistance under moderate hydrodynamic conditions, whereas flow separation at high intensities substantially lowers the wave energy dissipation. Conversely, <em>oyster reefs maintain wave energy dissipation across a broader hydrodynamic range due to the sharp-edged, rigid shells</em>. The enhanced wave attenuation by <em>oyster</em> reefs and their expected long-term persistence in the Wadden Sea presents an opportunity to complement existing gray coastal protection infrastructure as a nature-based solution. The parameterization of frictional wave energy dissipation presented here enables more accurate hydro-morphodynamic modeling of large-scale sediment dynamics in such soft-bottom environments.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"200 ","pages":"Article 104763"},"PeriodicalIF":4.2,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143906377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}