Coastal EngineeringPub Date : 2025-02-14DOI: 10.1016/j.coastaleng.2025.104727
Thomas J. van Veelen , Heidi Nepf , Suzanne J.M.H. Hulscher , Bas W. Borsje
{"title":"The thresholds of sediment resuspension within emergent vegetation under combined wave-current conditions – A flume experiment","authors":"Thomas J. van Veelen , Heidi Nepf , Suzanne J.M.H. Hulscher , Bas W. Borsje","doi":"10.1016/j.coastaleng.2025.104727","DOIUrl":"10.1016/j.coastaleng.2025.104727","url":null,"abstract":"<div><div>The threshold of resuspension can be described by a critical velocity. Salt marsh vegetation modifies the flow conditions such that the critical velocities for resuspension derived on bare beds no longer apply. Within vegetation canopies, the critical velocity for resuspension was previously shown to decrease under pure current and pure wave conditions. In this study, we experimentally investigated how emergent salt marsh vegetation affects resuspension under combined wave-current flows that are typical for intertidal coastlines. Emergent artificial vegetation canopies inspired by <em>Spartina Anglica</em> and fine noncohesive sediment were placed in a wave-current flume. We set a constant current and incrementally increased the wave height until resuspension was measured. We repeated this procedure with a bare bed, three stem densities, and for a range of wave-current combinations. The critical velocity for resuspension was significantly reduced by vegetation-induced turbulence. Turbulent vortices shed by the stems entrained sediment particles from the bed. The critical velocity for resuspension decreased by 35–64% compared to bare bed conditions, depending on a ratio between the current velocity and wave velocity amplitude. The critical velocity decreased the most under pure current flows and the least under pure wave conditions. Finally, with vegetation present, the stem density did not affect the threshold of resuspension for the range of densities tested here. Our results can be implemented into sediment transport models through an adjusted Shields parameter for vegetated beds, which can be used for the management of salt marshes and the design of interventions for nature-based coastal protection.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"199 ","pages":"Article 104727"},"PeriodicalIF":4.2,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143600690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Coastal EngineeringPub Date : 2025-02-14DOI: 10.1016/j.coastaleng.2025.104718
Shannon Brown, Annika O’Dea, Ian Conery, Katherine Brodie
{"title":"Assessing shorelines extracted from satellite imagery using coincident terrestrial lidar linescans","authors":"Shannon Brown, Annika O’Dea, Ian Conery, Katherine Brodie","doi":"10.1016/j.coastaleng.2025.104718","DOIUrl":"10.1016/j.coastaleng.2025.104718","url":null,"abstract":"<div><div>Numerous algorithms have been developed to facilitate the extraction of shoreline position from satellite imagery, including the CoastSat algorithm. Previous analyses comparing CoastSat satellite-derived shorelines (SDS) to morphological data have highlighted that there are site-specific errors in outputs that are likely related to concurrent wave runup conditions, but the data required to test this relationship are rarely available. Here, we present a novel comparison of lidar-derived runup and beach elevation data to CoastSat satellite-derived waterlines (SDW) extracted using two image sources (Sentinel-2 and PlanetScope) and two threshold algorithms (Otsu and weighted peaks). Results show that while SDW extracted using Otsu thresholds correlated better with lidar-derived waterlines (LDW), SDW extracted using the weighted peaks threshold were consistently positioned in the upper swash and therefore correlated better with a runup bulk statistic. Assigning the best-fit runup bulk statistic as the waterline elevation to weighted peaks SDW resulted in SDS with less scatter than the Otsu SDW due to the more consistent waterline elevation. Horizontal errors for the converted datum-referenced shoreline were lowest when SDW were converted to SDS using best-fit measured runup bulk statistics and a measured slope. However, for weighted peaks SDW from both image sources, assigning the best-fit parameterized runup bulk statistic and an average slope in the SDW to SDS conversion still reduced error by <span><math><mrow><mo>∼</mo><mn>20</mn><mtext>%</mtext></mrow></math></span> to <span><math><mrow><mo>∼</mo><mn>35</mn><mtext>%</mtext></mrow></math></span> when compared to the tidal elevation and average slope. These findings confirm that runup corrections can improve native SDS outputs, although the magnitude of the final shorelines error depended on the specific imagery product, local beach slope, threshold technique, runup parametrization, and chosen reference contour.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"199 ","pages":"Article 104718"},"PeriodicalIF":4.2,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143471625","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":"Minutely monitoring of swash zone processes using a lidar-camera fusion system","authors":"Yoshinao Matsuba , Yoshimitsu Tajima , Takenori Shimozono , Kévin Martins , Masayuki Banno","doi":"10.1016/j.coastaleng.2025.104724","DOIUrl":"10.1016/j.coastaleng.2025.104724","url":null,"abstract":"<div><div>The advancement of effective remote sensing technologies is critical for understanding the dynamics of coastal systems, enabling efficient and sustainable management strategies. Video cameras have been widely used for this purpose, significantly advancing our knowledge of coastal dynamics. However, traditional optical devices cannot directly provide three-dimensional (3D) information, such as beach profiles or runup heights. Recently, lidar scanners have gained attention within the coastal research community for their ability to directly capture high-resolution data on hydro-sediment interactions near shorelines across various scales, providing valuable insights into coastal dynamics. This study presents a fusion system that combines a 3D lidar with a video camera, capable of simultaneously capturing 3D coordinates and surface colors of beaches and nearshore waves. The fusion system was tested at two coastal sites in Japan, demonstrating its high potential for coastal monitoring. At the Hasaki coast, characterized by fine sand, it captured alongshore variations in topographic changes, linked to runup heights and seepage processes over one day. At the Namiita coast, characterized by a mixed sand-gravel beach, the fusion system observed the development of cusp structures over 3 h. The data suggest sand accumulation around gravel and gravel retrieval from the beach surface following an increase in tide level. Although this fusion system was tested at only two coastal sites in Japan, it demonstrates high flexibility and potential for studying swash zone processes across diverse spatiotemporal scales and beaches, including mixed sand-gravel beaches.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"199 ","pages":"Article 104724"},"PeriodicalIF":4.2,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143453922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"HF radar estimation of ocean wave parameters: Second-order Doppler spectrum versus Bragg wave modulation approach","authors":"Verónica Morales-Márquez, Dylan Dumas, Charles-Antoine Guérin","doi":"10.1016/j.coastaleng.2025.104719","DOIUrl":"10.1016/j.coastaleng.2025.104719","url":null,"abstract":"<div><div>We propose an original technique for the HF radar estimation of the main sea state parameters by exploiting the amplitude modulation of the radar signal time series. While the classical method for ocean wave measurement is based on the second-order ocean Doppler spectrum, this alternative approach uses the slow amplitude modulation of the Bragg wave in the radar signal. Using a nearby buoy and the WWIII model as ground truth, we apply this method to an annual set of HF radar data in the vicinity of Toulon (Mediterranean coast of France) and compare it with the classical formulas proposed by Barrick (1977) to derive the main wave parameters from the Doppler spectrum. Although the modulation approach is physically attractive and easier to implement, we find that the Doppler spectrum-based method is far superior at this stage in calculating the significant wave height and the peak wave frequency, even at long range.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"198 ","pages":"Article 104719"},"PeriodicalIF":4.2,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420950","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":"Drivers and predictability of extreme still water level trends and interannual variability along the coast of Australia across different time scales","authors":"Julian O'Grady , Alec Stephenson, Kathleen McInnes","doi":"10.1016/j.coastaleng.2025.104725","DOIUrl":"10.1016/j.coastaleng.2025.104725","url":null,"abstract":"<div><div>Still water levels, representing the height above a datum of a smooth water surface without surface waves, are typically measured by tide gauges in ports. In this study, we present an improved model for predicting non-stationary extreme still water levels (ESWL), which accounts for both deterministic ESWL driver components and a probabilistic component to account for stochastic influence of storm events using 30-year records (1990–2019) from 76 tide gauges around the Australian coast. The deterministic formulation of the model represents the non-stationarity of the trends in the overall ESWL driven by climate change, along with the individual contribution to interannual variability made by astronomical tidal cycles and ENSO variability. The probabilistic formulation of model represents the nature of remaining stochastic storm surge occurrence.</div><div>Our findings discuss significant ESWL trends, with and without background mean sea level rise included. A 4.4-year lunar tidal cycle significantly affects ESWL variability in northern Australia. While La Niña raises ESWLs at most sites, many in southeastern Australia are unaffected.</div><div>We use the model to examine high impact future climate contributions, which project an additional six-mm/year sea level rise and a 16% increase in ENSO by the end of the century. Our results suggest that sea level rise will dominate the other drivers and the projected increase in ENSO variability across Australia.</div><div>This model enables more precise predictions, identifying emerging thresholds for ESWL impacts in the coming decades. Here, improved coastal modelling efforts can inform planning and adaptation measures in response to rising sea levels.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"199 ","pages":"Article 104725"},"PeriodicalIF":4.2,"publicationDate":"2025-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143444323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Coastal EngineeringPub Date : 2025-02-06DOI: 10.1016/j.coastaleng.2025.104723
Ching Theng Liong , Xiaoxiao Yang , Eng Soon Chan , Ying Min Low
{"title":"Mechanics of energy dissipation due to wave plunging","authors":"Ching Theng Liong , Xiaoxiao Yang , Eng Soon Chan , Ying Min Low","doi":"10.1016/j.coastaleng.2025.104723","DOIUrl":"10.1016/j.coastaleng.2025.104723","url":null,"abstract":"<div><div>Marine operations in harsh conditions often involve extreme environments. Despite advancements in numerical schemes, challenges persist in modelling these wave fields. An example is the application of potential flow methodology, which is efficient but limited by its inadequacy in accounting for energy dissipation due to wave breaking. Currently, empirical dissipation models with coefficients calibrated against experimental observations are often used. However, how these coefficients vary across the broad range of wave breaking scenarios, ranging from incipient breaking to extreme wave plunging is not well understood. The purpose of this paper is to account for the variability of these coefficients through a better understanding of the dissipation mechanics. Using a validated two-phase Reynolds-Averaged Navier-Stokes (RANS) model, which reproduces the essential physics of a plunging wave, we not only reinforce existing observations on the total energy lost due to wave breaking but also show that, for a plunging wave, 77% of that energy loss is closely linked to the bifurcation of flow near the wave crest that contributed to wave breaking. Additionally, ∼19% of the energy loss may be attributed to the work done by the wave compressing the entrapped air. Together, the energy associated with both the plunging jet and the air entrapment could account for up to 96% of the total energy loss.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"198 ","pages":"Article 104723"},"PeriodicalIF":4.2,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377180","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}
Coastal EngineeringPub Date : 2025-02-06DOI: 10.1016/j.coastaleng.2025.104701
Menno P. de Ridder , Dennis C.P. van Kester , Patricia Mares-Nasarre , Marcel R.A. van Gent
{"title":"Individual overtopping volumes, water layer thickness and front velocities at rubble mound breakwaters with a smooth crest in shallow water","authors":"Menno P. de Ridder , Dennis C.P. van Kester , Patricia Mares-Nasarre , Marcel R.A. van Gent","doi":"10.1016/j.coastaleng.2025.104701","DOIUrl":"10.1016/j.coastaleng.2025.104701","url":null,"abstract":"<div><div>Individual overtopping events are important variables when designing a coastal structure as they can deviate significantly from the mean overtopping discharge. Thus, in this study, extreme overtopping events at rubble mound structures with a smooth crest in shallow water have been studied. Both the water layer thickness (flow depth), front velocity and individual overtopping volumes are measured in a wave flume for typical coastal structures with a smooth crest in shallow water for a large range of hydraulic conditions and three different foreshore slopes. An analysis of the individual overtopping volumes shows that the largest individual overtopping volumes arise from short waves that travel on the crest of a low-frequency wave in shallow water and short waves that travel on top of the trough in deep water. Due to the temporal water level variation caused by the low-frequency waves in shallow water, there are fewer overtopping events compared to deep water conditions with the same non-dimensional overtopping discharge. However, the individual overtopping volumes of these events are larger. To quantify the extreme overtopping variables, an empirical formulation based on the relative crest height and short-wave steepness is proposed for the non-dimensional 2 % exceedance water layer thickness, front velocity and individual overtopping volume in terms of incident waves with an <span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span> of 0.84, <span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span> of 0.55 and <span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span> of 0.85 respectively. A further small improvement is found when the low-frequency wave height and 2% exceedance wave height are included, but the added value of this expression does not outweigh the additional wave variables needed for the expression. A log-normal distribution with a constant shape and an expression for the scale of the distribution is proposed to describe the distribution of the individual overtopping volumes in shallow water which accurately captures the distribution (<span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span> of 0.90). Compared to most of the current design approach which is based on a cascade of empirical formulations, this is a significant improvement. In addition, the reasonable results for a distribution with a constant shape parameter show that the shape of the distribution does not change significantly for shallow water conditions.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"198 ","pages":"Article 104701"},"PeriodicalIF":4.2,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143388067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Coastal EngineeringPub Date : 2025-02-06DOI: 10.1016/j.coastaleng.2025.104720
Yefeng Cai , Haisheng Zhao , Xin Li , Wei Shi , Qing Xiao
{"title":"Developing an OpenFOAM solver for coupled aero-hydrodynamic analysis of integrated structure with floating offshore wind turbine and aquaculture net cage","authors":"Yefeng Cai , Haisheng Zhao , Xin Li , Wei Shi , Qing Xiao","doi":"10.1016/j.coastaleng.2025.104720","DOIUrl":"10.1016/j.coastaleng.2025.104720","url":null,"abstract":"<div><div>The integrated structure of floating offshore wind turbines (FOWTs) and aquaculture net cages has garnered significant attention in recent years. This study establishes, for the first time, a CFD analysis method for the integrated structure of FOWTs and aquaculture cages, and develops a specialized solver, HybridMarineFoam, for coupled analysis of the integrated structure. The solver currently includes aerodynamic, hydrodynamic, mooring, and aquaculture cage computation modules. The aquaculture cage module is based on the Darcy-Forchheimer model, incorporating the influence of the floating platform's motion into the Darcy-Forchheimer equation and accounting for the hydrodynamic impact of the cage on the floating platform, thus achieving coupled calculations between the fish cage and the floating platform. In this study, the force loading calculation for the moving aquaculture cage and the coupling simulation for the integrated structure have been very well validated. Subsequently, an integrated structure, combining an IEA 15 MW FOWT and an aquaculture cage, was proposed, and the HybridMarineFoam solver was used to analyze its aerodynamic, hydrodynamic, and flow field characteristics under different wind speeds, wave heights and water current speeds. The results reveal that the presence of the cage significantly impacts the system dynamics motion response and flow field characteristics of the floating wind turbine.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"198 ","pages":"Article 104720"},"PeriodicalIF":4.2,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377181","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}
Coastal EngineeringPub Date : 2025-02-05DOI: 10.1016/j.coastaleng.2025.104721
Wonhyun Lee, Alexander Y. Sun, Bridget R. Scanlon
{"title":"Probabilistic storm surge and flood-inundation modeling of the Texas gulf coast using super-fast INundation of CoastS (SFINCS)","authors":"Wonhyun Lee, Alexander Y. Sun, Bridget R. Scanlon","doi":"10.1016/j.coastaleng.2025.104721","DOIUrl":"10.1016/j.coastaleng.2025.104721","url":null,"abstract":"<div><div>Accurately predicting flood extent and depths, encompassing storm surge, pluvial, and fluvial flooding, is important for protecting coastal communities. However, high computational demands associated with detailed probabilistic models highlight the need for simplified models to enable rapid forecasting. In this study we developed an ensemble-based probabilistic forecast framework using a reduced-complexity, hydrodynamic solver – the Super-Fast INundation of CoastS (SFINCS) model. The framework was showcased over Hurricane Ike that significantly impacted the Texas Gulf Coast in 2008. Results demonstrate the capability of the SFINCS model to generate probabilistic predictions (e.g., ≤4 h for a 100-member ensemble on a single multi-core CPU). The model agrees well with observed data from NOAA tidal, USGS stream gage height, and FEMA high water mark stations. Compared to a deterministic approach, the ensemble method reduced errors by an average 16% across all water level and hydrograph stations. Sensitivity analysis indicated consistent patterns of flood inundation across varying ensemble sizes (81, 189, 1,000) and lead times (1–3 days before landfall), with a slight increase in uncertainty for smaller ensembles and longer lead times. In particular, counties adjacent to the Trinity River Basin had ≥80% probability of exceeding the critical 3-m flooding depth during Hurricane Ike. Our study highlights the effectiveness of the SFINCS-based ensemble framework in providing probabilistic flood extent/depth forecasts over long lead times in a timely manner. Thus, the framework constitutes a valuable tool for effective flood preparedness and response planning during flooding events.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"198 ","pages":"Article 104721"},"PeriodicalIF":4.2,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143372740","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}