Coastal Engineering最新文献

{"title":"Variation in flow characteristics of overtopping waves on dike crests","authors":"Niels van der Vegt ,&nbsp;Jord J. Warmink ,&nbsp;Bas Hofland ,&nbsp;Vera M. van Bergeijk ,&nbsp;Suzanne J.M.H. Hulscher","doi":"10.1016/j.coastaleng.2025.104772","DOIUrl":"10.1016/j.coastaleng.2025.104772","url":null,"abstract":"<div><div>During severe storms, waves can overtop dikes, leading to erosion of the crest and landward slope, which may ultimately result in breaching. To accurately model this erosion, the overtopping flow needs to be described in a time-dependent manner for each individual wave overtopping event. The peak flow velocity (<span><math><msub><mrow><mi>u</mi></mrow><mrow><mi>p</mi><mi>e</mi><mi>a</mi><mi>k</mi></mrow></msub></math></span>) and peak flow thickness (<span><math><msub><mrow><mi>h</mi></mrow><mrow><mi>p</mi><mi>e</mi><mi>a</mi><mi>k</mi></mrow></msub></math></span>) are critical boundary conditions in this context. Previous studies have shown that these flow characteristics are related to the overtopping volume, yet often propose deterministic models that overlook the variability and interdependency between these characteristics.</div><div>The goal of this study is to address these gaps by explicitly quantifying the variation and interdependence of <span><math><msub><mrow><mi>u</mi></mrow><mrow><mi>p</mi><mi>e</mi><mi>a</mi><mi>k</mi></mrow></msub></math></span> and <span><math><msub><mrow><mi>h</mi></mrow><mrow><mi>p</mi><mi>e</mi><mi>a</mi><mi>k</mi></mrow></msub></math></span>, using data from small-scale FlowDike experiments. We propose generalized distributions to describe the variation in these flow characteristics, with <span><math><msub><mrow><mi>u</mi></mrow><mrow><mi>p</mi><mi>e</mi><mi>a</mi><mi>k</mi></mrow></msub></math></span> varying by 13% to 23%, depending on the waterside slope angle, and <span><math><msub><mrow><mi>h</mi></mrow><mrow><mi>p</mi><mi>e</mi><mi>a</mi><mi>k</mi></mrow></msub></math></span> varying by approximately 20%. Furthermore, the interdependency between <span><math><msub><mrow><mi>u</mi></mrow><mrow><mi>p</mi><mi>e</mi><mi>a</mi><mi>k</mi></mrow></msub></math></span> and <span><math><msub><mrow><mi>h</mi></mrow><mrow><mi>p</mi><mi>e</mi><mi>a</mi><mi>k</mi></mrow></msub></math></span> is modeled using a Student-t copula (<span><math><mrow><mi>ν</mi><mo>=</mo><mn>9</mn><mo>.</mo><mn>361</mn></mrow></math></span>, <span><math><mrow><mi>ρ</mi><mo>=</mo><mo>−</mo><mn>0</mn><mo>.</mo><mn>497</mn></mrow></math></span>), revealing a moderate negative correlation. This suggests that overtopping events with a high <span><math><msub><mrow><mi>u</mi></mrow><mrow><mi>p</mi><mi>e</mi><mi>a</mi><mi>k</mi></mrow></msub></math></span> are less likely to have a large <span><math><msub><mrow><mi>h</mi></mrow><mrow><mi>p</mi><mi>e</mi><mi>a</mi><mi>k</mi></mrow></msub></math></span>, and vice versa.</div><div>The findings of this study can be directly applied to improve models that describe the loading caused by overtopping waves and the resulting erosion. By incorporating the variation and interdependence of <span><math><msub><mrow><mi>u</mi></mrow><mrow><mi>p</mi><mi>e</mi><mi>a</mi><mi>k</mi></mrow></msub></math></span> and <span><math><msub><mrow><mi>h</mi></mrow><mrow><mi>p</mi><mi>e</mi><mi>a</mi><mi>k</mi></mrow>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"201 ","pages":"Article 104772"},"PeriodicalIF":4.2,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144154827","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":"Boussinesq modeling of typhoon-induced infragravity oscillations in Hualien Harbor, eastern Taiwan: Influence of the adjacent coast","authors":"Shih-Feng Su ,&nbsp;Gangfeng Ma","doi":"10.1016/j.coastaleng.2025.104789","DOIUrl":"10.1016/j.coastaleng.2025.104789","url":null,"abstract":"<div><div>Large infragravity-wave oscillations inside harbors are generally induced by typhoon-generated swell waves. The interaction between infragravity waves and harbor geometry can significantly amplify wave oscillations when the specific frequencies match the natural resonance frequencies of the harbor. Additionally, the neighboring coastal morphology can enhance the influx of infragravity energy. In this study, we investigated infragravity oscillations in Hualien Harbor, eastern Taiwan, during the passage of a strong typhoon. The harbor geometry comprises outer and inner basins aimed at providing a well-sheltered area. However, the extreme infragravity wave height of 2.0 m was observed at the innermost basin. A wave-resolving Boussinesq model was applied to reproduce harbor oscillations and was validated against the measured data within the port. The accuracy of the simulated significant wave heights was sensitive to the direction of the incident wave, but not that of the simulated infragravity waves. Furthermore, lower and higher resonance frequencies prevail in the inner and outer basins, respectively. The simulated spatial distributions of wave heights in the resonance periods demonstrated that these waves were present both within the harbor and along the adjacent coast. Additionally, the refraction effects of the adjacent coast were investigated through numerical simulations. Our experiments revealed that the infragravity energy generated on the adjacent coast contributed to an increase in infragravity wave heights inside the harbor up to 47 %. Moreover, we found that reducing the long-period infragravity waves significantly altered the distribution of short-period swell waves in the outer harbor basin.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"201 ","pages":"Article 104789"},"PeriodicalIF":4.2,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144105100","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":"Drag coefficient prediction model for simulating breaking waves propagating on partly submerged vegetated sloping beaches using a RANS model","authors":"Yanxu Wang ,&nbsp;Quanlin Qiu ,&nbsp;Zegao Yin ,&nbsp;Xiutao Jiang ,&nbsp;Xuan Zhang","doi":"10.1016/j.coastaleng.2025.104788","DOIUrl":"10.1016/j.coastaleng.2025.104788","url":null,"abstract":"<div><div>Accurate prediction of vegetation drag coefficients (<em>C</em>_D) is crucial for simulating breaking wave propagation on partly submerged vegetated sloping beaches. This study conducted a comprehensive investigation involving physical experiments and numerical modeling to address the limitations of existing empirical formulas for <em>C</em>_D. The experiments varied incident wave heights (<em>H</em>_i = 0.02–0.10 m), wave periods (<em>T</em> = 1.0–1.8 s), vegetation densities (<em>N</em>_v = 41–590 units/m²), vegetation zone lengths (<em>L</em>_v = 0.8–1.6 m), and beach slope gradients (<em>m</em> = 1/10–1/30), generating a database of 750 calibrated <em>C</em>_D values. Numerical simulations using a Reynolds-Averaged Navier-Stokes (RANS) model coupled with the stabilized <em>k−ω</em> SST turbulence model and the volume-of-fluid (VOF) method revealed that <em>C</em>_D correlates strongly with the Iribarren number (<em>ξ</em>₀), while being highly sensitive to vegetation density and zone length. Two prediction models were developed: a multivariate nonlinear regression (MNLR) model and an M5P-tree machine learning model. Both models utilized <em>ξ</em>₀, vegetation volume fraction (<em>φ</em>), and relative vegetation zone length (<em>λ</em>_<em>L</em>) as input parameters. The MNLR model provided a compact formula with moderate accuracy (<em>R</em> = 0.87, <em>RMSE</em> = 0.77), while the M5P-tree model partitioned the parameter space using <em>φ</em> and <em>ξ</em>₀, generating three tailored sub-models with superior performance (<em>R</em> = 0.91, <em>RMSE</em> = 0.64). Further validation with independent datasets confirmed that the M5P-tree model outperformed the MNLR model in simulating wave height evolution over vegetated sloping beaches. These findings demonstrate the potential of the M5P-tree model as a robust tool for enhancing simulations of breaking wave propagation on vegetated sloping beaches and optimizing vegetated coastal defenses.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"201 ","pages":"Article 104788"},"PeriodicalIF":4.2,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144105099","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 framework to mitigate aeolian erosion on nourished beaches","authors":"Yanyu He ,&nbsp;Feng Cai ,&nbsp;Jianhui Liu ,&nbsp;Hongshuai Qi ,&nbsp;Bailiang Li ,&nbsp;Chao Cao ,&nbsp;Shaohua Zhao ,&nbsp;Gen Liu ,&nbsp;Xu Chen ,&nbsp;Jiaqi Huang","doi":"10.1016/j.coastaleng.2025.104771","DOIUrl":"10.1016/j.coastaleng.2025.104771","url":null,"abstract":"<div><div>Beach nourishment has become a widely adopted nature-based strategy for coastal protection worldwide. However, in regions prone to strong winds, the topographic changes induced by beach nourishment—particularly elevated nourished berms—can significantly alter near-surface wind fields and aeolian sand transport processes. This study integrates field observations with numerical modeling to examine how topographic modifications induced by beach nourishment can influence the coastal aeolian sand transport mechanisms. The key findings are as follows: (1) The elevated beach berms lead to a localized increase in wind speed and a segmented fetch system, with the latter plays a dominant role in limiting the development and transport of aeolian sand streamers; (2) By incorporating the interactions between the transport-stimulated effect of wind intensification and the transport-limited effect of fetch segmentation induced by nourished berm, a “piecewise” model framework was proposed for the aeolian sand transport of nourished beaches, which significantly improving the accuracy of numerical modeling; (3) Based on the improved sand transport model, an optimal beach nourishment design for windy coasts was discussed, and a multi-tiered, mechanically graded berm nourishment approach was recommended to minimize the aeolian sand transport across beach surface.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"201 ","pages":"Article 104771"},"PeriodicalIF":4.2,"publicationDate":"2025-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144068357","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":"Influence of bed ripples on scour-induced span elongation of pipelines/cables","authors":"Bingchang Zhang ,&nbsp;Scott Draper ,&nbsp;Hongwei An ,&nbsp;Hongyi Jiang ,&nbsp;Liang Cheng","doi":"10.1016/j.coastaleng.2025.104777","DOIUrl":"10.1016/j.coastaleng.2025.104777","url":null,"abstract":"<div><div>This study presents results from laboratory experiments designed to investigate the scour propagation along a pipeline/cable under steady current. Most previous research on this topic has shown that the scour propagation has a primary and secondary stage, with the transition to the secondary stage believed to occur when the scour hole reaches some critical length. However, results from the present study show that in small-scale model testing, bed ripples have a direct influence on scour rate, causing a transition from a primary to secondary stage as they develop. This is demonstrated by comparing scour propagation rates before and after ripples develop upstream of the pipeline/cable, and after ripples are removed by flattening the upstream bed. It is found that bed ripples appear to have both an indirect and direct influence on scour propagation. Indirectly, ripples reduce near-bed velocity by altering the boundary layer, while directly they deflect flow upwards, sheltering the pipeline/cable and reducing flow into the scour front. Additionally, the sediment flux entering the scour front may be altered by the proximity of upstream ripples, potentially leading to temporary cessation of scour propagation. The findings from this work have implications both for interpreting scour results in earlier research and for designing future experimental models.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"201 ","pages":"Article 104777"},"PeriodicalIF":4.2,"publicationDate":"2025-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144070123","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 and numerical investigation of the dynamic response of coastal box-girder superstructures considering rotational effects under extreme wave loading","authors":"Bo Huang ,&nbsp;Minglin Chen ,&nbsp;Zhiying Yang ,&nbsp;Jianting Zhou ,&nbsp;Dan Zhong ,&nbsp;Jiawei Zhou","doi":"10.1016/j.coastaleng.2025.104774","DOIUrl":"10.1016/j.coastaleng.2025.104774","url":null,"abstract":"<div><div>Due to the rising frequency of extreme marine disasters, research on the interaction between coastal bridges and waves has gained significant attention in recent years. Bridge superstructures are typically subjected to rotation or even overturning failure under extreme wave conditions. However, existing experimental studies have scarcely accounted for these effects under extreme wave conditions. Thus, a steel rotating shaft system was employed in this study to implement the rotational effects of the superstructure. Subsequently, the influence of bridge piers and adjacent structures was considered, followed by a series of fluid-structure interaction experiments and numerical simulations to more accurately investigate the wave forces and dynamic response of the rotatable box-girder superstructure (BGSS) under extreme wave conditions. Moreover, a comparison of existing wave force calculation formulas was conducted, and an empirical formula for predicting the wave forces on the BGSS, incorporating the rotational effects under extreme wave loadings, was proposed. The results demonstrate that accounting for the rotational effects of the BGSS enables a more realistic and accurate representation of the dynamic response of the superstructure under practical conditions. Furthermore, a reduction in the wave period or the submersion coefficient of the superstructure leads to an increase in the inclination and wave forces acting on the BGSS. The empirical formula proposed in this study is capable of accurately predicting the wave forces acting on the BGSS, considering rotational effects, when subjected to extreme waves.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"200 ","pages":"Article 104774"},"PeriodicalIF":4.2,"publicationDate":"2025-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143936515","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 shoreline orientation variation across diverse coastal environments","authors":"Mayowa Basit Abdulsalam ,&nbsp;Camilo Jaramillo ,&nbsp;Lucas de Freitas ,&nbsp;Mauricio González ,&nbsp;José A.Á. Antolínez","doi":"10.1016/j.coastaleng.2025.104770","DOIUrl":"10.1016/j.coastaleng.2025.104770","url":null,"abstract":"<div><div>Understanding and predicting shoreline variability at various temporal and spatial scales is vital for effective, data-driven coastal management. Shoreline position, a reliable indicator of beach morphological changes, has been assessed using complex numerical models. Recently, equilibrium-based shoreline evolution models (EBSEMs) have gained traction for their efficiency in simulating shoreline orientation, including cross-shore and rotational (longshore) changes. However, existing EBSEMs for shoreline rotation have been applied predominantly to microtidal beaches, with limited validation across diverse coastal environments.</div><div>This study evaluates the performance and scalability of the EBSEM proposed by Jaramillo et al. (2021) in modelling shoreline rotational variability at seven embayed beaches: Narrabeen Beach (Australia), Tairua Beach (New Zealand), Blackpool Beach (United Kingdom), Poniente Beach, Llevant Beach, Cala Millor Beach, and Moncofa Beach (Spain). These sites represent diverse environmental conditions in terms of sediment size, tidal regimes, monitoring frequency, and data types. The model was tested across full monitoring periods, elevation contours, and temporal resolutions.</div><div>Results show that EBSEM performs well across contrasting beach types, effectively capturing short-term and seasonal shoreline rotation patterns. However, reduced accuracy was observed in environments with high-energy events or human interventions, such as Poniente, Llevant, and Cala Millor beaches. Sensitivity analyses highlight the importance of temporal resolution and intertidal elevation in model performance.</div><div>While the EBSEM shows significant potential for broader application, further refinement is needed to better capture storm-driven and anthropogenic variability. These improvements would enhance its utility for coastal adaptation planning, hazard mitigation, and long-term shoreline management in the face of climate change.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"200 ","pages":"Article 104770"},"PeriodicalIF":4.2,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143899684","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 fully spectral framework for nonlinear water waves propagating over topography","authors":"Maciej Paprota","doi":"10.1016/j.coastaleng.2025.104759","DOIUrl":"10.1016/j.coastaleng.2025.104759","url":null,"abstract":"<div><div>A problem of nonlinear water waves propagating over uneven bottom is considered. The proposed solution is based on a fully spectral Fourier-Galerkin method. Hence, higher-order terms appearing in free-surface and bottom boundary conditions are calculated entirely in a wave number space as convolution sums. In this way, the nonlinear terms may be efficiently determined using either a direct convolution method for smaller kernels or an FFT-based procedure for larger spectral domains. An implementation-ready form of a linear system of equations that bonds velocity potential coefficients at the surface and at the bottom is reported. In static topography conditions, the fast solution of the system is achieved due to precomputed factorization. The numerical model is applied to waves propagating over a bottom of various geometries, including abrupt topographies with upright slopes approximating transformation of waves over a shelf due to a considerable decrease in water depth. The accuracy of the solution is confirmed for a propagation of linear and nonlinear waves of permanent form including solitons, linear and nonlinear shoaling, reflection and transmission of linear waves at an underwater step, and landslide generated linear waves. An application of the method to a tsunami wave undergoing transformation over an abrupt bottom junction is presented along with the discussion on nonlinear wave processes strongly affecting the resulting transmitted tsunami profile.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"200 ","pages":"Article 104759"},"PeriodicalIF":4.2,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143891096","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":"Adaptive covariance tapering for large datasets and application to spatial interpolation of storm surge","authors":"Christopher Irwin ,&nbsp;Alexandros A. Taflanidis ,&nbsp;Norberto C. Nadal-Caraballo ,&nbsp;Luke A. Aucoin ,&nbsp;Madison C. Yawn","doi":"10.1016/j.coastaleng.2025.104768","DOIUrl":"10.1016/j.coastaleng.2025.104768","url":null,"abstract":"<div><div>Covariance tapering is a popular approach for accommodating computational efficiency for the application of Gaussian process (GP) -based spatial interpolation for large datasets. This is accomplished by introducing sparsity in the <span>GP</span> covariance matrix, through the introduction of a compactly supported taper function. The support of the taper function around each spatial node is defined through the taper range variable. The latter is selected to achieve the desired degree of global sparsity in the covariance matrix, and defines the number of connected neighbors (i.e., local sparsity) around each node. For problems with irregular nodal density, adaptive covariance tapering can be used to improve accuracy for the taper implementation. In this case, the taper ranges of the taper function have spatial variability, allowing uniform local sparsity to be achieved despite the data irregularities. The optimization of the taper ranges to accomplish this objective has a computational burden that is dependent on the size of the database, prohibiting its application to very large datasets. This paper formally considers the adoption of adaptive covariance tapers for such datasets. Though algorithmic developments are general, the problem is discussed for a specific application, the spatial interpolation of storm surge. For establishing computational efficiency in the optimization of the taper ranges we propose to utilize only a small subset of nodes, termed inducing points. An adaptive, iterative formulation is further developed to support the selection of the inducing points, shown to be critical for achieving the desired local sparsity for the remaining points. At each iteration, the taper range selection is performed using the current subset of inducing points, the achieved sparsity across all nodes is estimated, and then new inducing points are added within the sub-regions for which the discrepancy from the target local sparsity is the largest. The latter points are considered to have the highest expected utility as inducing points. Adding inducing points in close proximity is avoided through the inclusion of a clustering step. The implementation is demonstrated for interpolation of peak storm surge along the New Jersey coast, using two different domains, one with 64,379 nodes and one with 271,669 nodes.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"201 ","pages":"Article 104768"},"PeriodicalIF":4.2,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144312895","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 runup extraction on dissipative beaches: New video-based methods","authors":"Meye J. van der Grinten ,&nbsp;Jakob C. Christiaanse ,&nbsp;Ad J.H.M. Reniers ,&nbsp;Falco Taal ,&nbsp;Jens Figlus ,&nbsp;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}