bluuebunny/crossref_metadata_2025 huggingface dataset:
MECHANICS OF SHOALING AT THE HOUSTON SHIP CHANNEL’S BAYPORT FLARE
Authors: Kerr Patrick Corbitt , Ritz Michael , Brownell Lori , Dellapenna Tim , Figlus Jens , McAlpin Jennifer , Maglio Coraggio , Garrett Jacob
Published: September 2023

The Houston Ship Channel (HSC) is one of the most vital and busiest deep-draft navigation channels in the United States. In 2019 in partnership with the Port of Houston, the U.S. Army Corps of Engineers Galveston District (SWG) completed a five-year award-winning mega feasibility study for the HSC Engineering Channel Improvement Project (ECIP). As part of the 2019 HSC ECIP Feasibility Report Environmental Impact Statement (FREIS) and, through ongoing and repeated maintenance events, the Bayport Flare (Flare) was noted as an area of concern due to chronic shoaling that disrupts traffic and requires continuous dredging. The Flare is the intersection of the HSC and Bayport Ship Channel (BSC). This study seeks to (1) improve our understanding of the source and mechanisms for generation of shoaling and (2) develop and assess conceptual alternative countermeasures for shoaling mitigation. To assess and isolate the sources and mechanics of shoaling in the Flare, a multiple layer approach was applied, which included both field and numerical investigations. A workshop was held to develop alternative countermeasures based on the understanding of system dynamics. Alternatives will (1) be optimized based on cost-benefit considerations; (2) have no-adverse impact on navigation nor require revision, to the point practicable, of ongoing ship simulation studies; and (3) may be structural, non-structural or OandM based.
OBSERVATIONS FROM A CONTROLLED DUNE EROSION EXPERIMENT UNDER VARIABLE WATER LEVELS, WAVES, AND INTERNAL DUNE MOISTURE CONTENT
Authors: Conti Stefano , Splinter Kristen D , Booth Emily , Djaidiguna Dominique , Turner Ian L
Published: September 2023

Dune erosion due to storms is primarily predicted by the use of empirical relationships, for example, when the duneface slope exceeds a certain threshold sand is eroded (SBeach, XBeach); or as a function of wave impact (Larson et al., 2004). However, geotechnical properties also play a role in dune scarp formation. Dry sand is relatively unstable, but as water is added, the tensile strength increases, enabling a vertical duneface to form and reduce slumping. The strength and stability of the sand matrix increases up to 10-15 percent with increasing water content, and then decreases as the sand matrix becomes saturated and more easily eroded. Hence, it is somewhat surprising that the importance of water infiltration into the dune sand matrix and resulting porewater content have received relatively limited attention within the coastal engineering literature to-date. This paper presents new results from a series of controlled laboratory experiments to observe moisture content and pore pressures within an eroding dune, to better understand the importance of wave run-up infiltration to dune erosion under wave attack.
IMPLICATIONS OF SPATIAL GRAIN SIZE VARIABILITY FOR AEOLIAN TRANSPORT
Authors: Ijzendoorn Christa van , Hallin Caroline , Vries Sierd de
Published: September 2023

Coastal dunes are crucial for coastal protection, habitat development and recreation. In recent years, their strength as a long-term building with nature approach has been explored in engineering projects. To improve implementation strategies, prediction of the development of the dune system is necessary. Aeolian sediment transport models may aid in informed design and decision-making. However, many aspects of aeolian sediment transport models need a thorough understanding to give reliable predictions. This research particularly focuses on grain size and assesses its effects on aeolian sediment transport at varying spatial and temporal scales. The aim is to provide recommendations on the relevance of spatial grain size variations in aeolian sediment transport modelling for coastal maintenance applications. For this purpose, we apply the aeolian sediment transport model AeoLiS, which allows for multi-fraction transport simulations (Hoonhout, 2017).
STRENGTHENING COASTAL DEFENCE WITH ARTIFICIAL DUNES
Authors: Rauwoens Pieter , Strypsteen Glenn , Derijckere Jennifer , Bonte Dries , Provoost Sam , Verwaest Toon , Muylaert Steven , Besien Peter Van
Published: September 2023

The Belgian coast is primarily sandy and is locally subject to erosion (Deronde, 2004). Traditionally, erosion was counteracted using hard engineering structures like groynes, seawalls and sea dikes. Nowadays, the Belgian government uses a different strategy by adopting a more soft and dynamic approach where possible. Many ‘soft’ managing activities at the Belgian coast are carried out in the form of regular and routine sand nourishments to cope for future flooding risks and coastal erosion (Houthuys, 2012). This method gives room to a new approach for coastal management where the natural elements and processes facilitate the development of new engineered dune areas at locations where traditional dike structures currently protect the hinterland. In the context of climate change and strict requirements for water safety, these hard to adapt engineering structures will not resist future flood events and more innovative solutions like dune in front of a dike principles to deal with rising sea level are receiving considerable attention. As a result, concepts are worked out in which traditional sea dikes are reinforced with newly created dune systems, offering a high level of protection of coastal infrastructure and at the same time offering a more natural appearance and higher ecological and socio economical values. In the framework of the SARCC project, one pilot site is realized in Raversijde. Besides the coastal defense function of the artificial dune, a second benefit is achieved: mitigating the nuisance, created by aeolian sand transport and preventing roads and tram tracks at the dike crest to be buried in sand.
SPATIO-TEMPORAL ANALYSIS OF SCOUR AROUND JACKET TYPE OFFSHORE FOUNDATIONS UNDER CLEAR WATER AND LIVE BED CONDITIONS
Authors: Satari Ramish , Welzel Mario , Schendel Alexander , Neuweiler Insa , Schlurmann Torsten
Published: September 2023

As an important contribution to the fulfilment of renewable energy targets, the offshore wind sector in Europe has grown significantly over the past decade (WindEurope 2021). Jacket structures are becoming more widely used as substructures for offshore wind turbines to accommodate the expansion towards greater water depth and to provide a stable basis for megastructures with hub heights greater than 200 m. However, there have been few studies (Chen et al., 2014; Baelus et al., 2018; Welzel et al., 2019; Welzel et al., 2020) that systematically address scour development at jacket structures. In addition, while the local equilibrium scour depth around pile foundations has been studied extensively in the past (e.g. Melville and Coleman, 2000; Sumer and Fredsøe, 2001; Schendel et al., 2020), there have been few studies on the development of spatial scour patterns, particularly around more complex offshore structures such as jackets. In this context, this study aims to improve the understanding of scour development around jacket type offshore wind foundations.
MIXED-SEDIMENT DYNAMICS AT A BACK-BARRIER BEACH NOURISHMENT
Authors: Bosma Jorn , Price Timothy , Ruessink Gerben
Published: September 2023

Sand nourishments are increasingly applied to systems where the morphodynamics are driven by mixed hydrodynamic forcing (i.e., tides and waves) rather than by waves alone. Here, mixed-sand deposits are usually retrofitted to inadequate, hard flood defenses to act as a buffer against erosion and eventually failure of such infrastructure. Introducing different grain sizes into a system leads to more complex, differentiated sediment transport, as coarser fractions are mobilized under different conditions than finer fractions (McCarron et al., 2019). By focusing on a nourishment on the leeward side of a barrier island, we aim to find quantitative answers to the questions where, when and how the mixed-sediment composition changes and how that already is and will be expressed in the morphologic evolution of the area.
NUMERICAL MODELING OF BAR-BUILT ESTUARIES AND IMPLICATIONS FOR THE MANAGEMENT OF INTERMITTENT INLETS
Authors: Velasquez-Montoya Liliana , Orescanin Mara , Williamson Cynthia , Cavins Alexander , Brenan Colin , Nguyen Nicole
Published: September 2023

Bar-built estuaries are common in tropical and temperate regions, accounting for nearly 3 percent of the estuaries throughout the world (McSweeney et al. 2017). Bar-built estuaries tend to have intermittent inlets that can open from the estuary side outward in regions with seasonal changes in river discharge (Kraus et al., 2008; Orescanin and Scooler 2018). It is well known that intermittent inlet dynamics primarily depend on the interplay between wave energy and inlet discharge driven by lagoon water levels (Rich and Keller, 2013). Forcing processes are generally understood, however, less is known about their interaction or thresholds, which is ultimately what drives the closure of intermittent inlets. The aim of this study is to explore numerical modeling techniques and parameters to simulate the hydrodynamics and closure of intermittent inlets in bar-built estuaries. Increasing the understanding of the conditions that lead to closing of intermittent inlets would allow for improved flood, sediment, and water quality management in the communities surrounding bar-built estuaries.
THE CASE OF SEDIMENT OUTFLOW FROM MOUNTAIN TO THE COAST DUE TO SMALL AND MEDIUM-SIZE FLOODS
Authors: Miyata Ryuhei , Akiyama Reiko , Horie Takehito , Noshi Yasuhito , Iguchi Kei
Published: September 2023

Smaller rivers in Japan can be characterized as having short distances from the mountainous areas of the source of sediment production to the estuary and steep slopes. Therefore, sediment produced from the mountains and river channels at the time of flooding immediately contributes significantly to the sediment dynamics at the estuary and coast in a short period of time. On the other hand, there have been few observations or studies that have measured the volume of landslides and riverbed fluctuations in the mountains in the entire basin before and after the occurrence of flooding, and quantitatively linked them to the amount of landslide movement and shoreline changes in the entire basin. This paper discusses the Chitose River basin (basin area A: 30km2, river channel distance L: 0.179km, stream gradient I: 1/14) and the Niizaki River basin (A: 16km2, L: 0.213km, I:1/17), which have an estuary on the Yugawara coast in Kanagawa Prefecture. The effect of sediment production from mountains and riverbeds at the time of flooding on coastal sediment dynamics on July 3rd, 2021.
IMPACT OF LONGSHORE SEDIMENT TRANSPORT ON THE DESIGN AND MAINTENANCE OF LOW-ENERGY, NON-TIDAL SANDY BEACHES
Authors: Ton Anne , Vuik Vincent , Wilmink Rinse , Aarninkhof Stefan
Published: September 2023

When low-energy, non-tidal lake beaches have a flood safety function, such as at the Houtribdijk, the Netherlands, sediment losses can directly affect the functioning of the beach (fig. 1). Detailed understanding of morphodynamic processes is needed to enable reliable predictions of the morphological development and the design of efficient maintenance strategies. Ton et al. (2021) showed that the development of these beaches is driven by both cross-shore and longshore processes. Wave action causes a distinct cross-shore profile shape to develop, with a steep beach face and a gently sloped platform around the depth of closure. However, on top of that, the combined effect of large-scale horizontal flow circulations (caused by gradients in storm surge level across the lake, Ton et al., submitted) and wave-induced sediment stirring was found to be an important driver of sediment losses along the beaches. In this work, we research how longshore transport (LST) can best be determined for low-energy lake beaches and classify and quantify the uncertainties related to this method.
OBSERVATIONS AND MODELING OF EROSION AND RECOVERY OF A COUPLED BEACH-DUNE SYSTEM
Authors: Long Joseph W. , Vincent Matthew B. , Hawkes Andrea D.
Published: September 2023

The geomorphic and ecological vulnerability of barrier islands is influenced by the way they respond to oceanographic and anthropogenic forcing over a broad range of temporal scales. Integrated models capable of simulating these processes are increasingly necessary to understand barrier island trajectories under future conditions and to aid in management decisions by evaluating the impact of potential restoration activities. While there are numerical models capable of simulating some of the dominant barrier processes, the role of beach berm evolution is rarely included despite the important function of berms in sustaining beaches, enabling dune growth via Aeolian transport, and mitigating backshore and dune erosion during storm events. This is primarily due to a lack of available data that resolves details of beach profile evolution at necessary temporal scales (e.g., seasonal, post-storm recovery, etc.) to test and develop models and the inherent difficulty of including these intra-annual processes into decadal scale models of barrier island evolution. Here we describe a unique and growing dataset of environmental forcing and barrier island topographic change. We also use the dataset to develop and test a model for barrier island evolution and quantify the role of storms, moderate wave conditions, and wind-driven transport in dictating coastal change on various timescales.
MIGRATION AND WELDING OF AN ESTUARINE BARRIER-SPIT DRIVEN BY DELTA EVOLUTION AND STORMS
Authors: Kinsela Michael , Owers Chris , Power Hannah , Doyle Tom , Hanslow David
Published: September 2023

As sea levels rise globally in response to anthropogenic climate change, coastal depositional systems that persist in dynamic equilibrium with accommodation space, sediment supply and hydrodynamic processes may begin to respond by redistributing sediment, causing erosion or migration of landforms that may have appeared as stable over previous decades to centuries. In contrast, systems that have adjusted to inherited or changing boundary conditions over historical times offer insights on the modes and timescales of potential future change in remobilised coastal systems. We investigate the coupled evolution of an estuarine sand barrier-spit and tidal delta over the past century, focusing on storm-driven erosion and overwash during recent decades that triggered recurrent barrier migration (rollover), ultimately welding it to the bedrock valley framework. Historical aerial photographs and recent high-resolution satellite and aerial imagery are analysed to map morphological change and calculate decadal trends in shoreline and barrier migration. Ocean wave and water level conditions between image dates capturing notable responses are analysed using wave and tide records from nearby measurement stations.
ADVANCES ON THE USE OF SATELLITE DERIVED PRODUCTS TO DETECT COASTAL CHANGES: DEMONSTRATION CASE ON THE COAST OF SPAIN
Authors: Silva Paula Gomes da , Martinez Jara , Beck Anne-Laure , Taji Amine , Medina Raúl , González Mauricio
Published: September 2023

Regular and efficient monitoring of coastal changes is necessary to inform coastal management decisions. In this regard, recent developments based on Google Earth Engine (Gorelick et al., 2017) enable the automatic detection of coastal changes using satellite data (Turner et al., 2021) However, such tools are usually calibrated with limited information and, consequently, they may lead to significant errors when applied to beaches with different conditions than those considered in the calibration data sets. In this work, we evaluate the capability to monitor changes in coastal morphology at various temporal and spatial scales using satellite-derived data obtained from an automatic processing method that includes site-specific information. These method was developed within the framework of the Coastal Erosion from Space Project (https://coastalerosion.argans.co.uk/) that brought together experts from several countries with different backgrounds, such as Earth Observation, Geology, Engineering and Management, to develop satellite products to monitor coastal change based on end-user requirements.
FACTORS CONTROLLING THE EQUILIBRIUM SEDIMENT COMPOSITION IN SAND-MUD TIDAL BASINS
Authors: Alonso Ana Colina , Maren Bas van , Herman Peter , Wang Zheng-Bing
Published: September 2023

Bed sediments in estuaries and tidal basins often consist of sand and mud, which can be deposited as uniform mixtures or as layers with varying mud content. Segregation between muddy and sandy areas is usually observed over large spatial scales (with sandy outer areas gradually fining in the landward direction), but also over small spatial scales. These small spatial scales are characterized by abrupt transitions of the sediment composition over relatively short distances. Understanding where sand and mud prevails is crucial to understand and predict coastal evolution and biological activity.
SHELL HASH: A NATURE-BASED SOLUTION FOR BEACHFRONT COASTAL RESILIENCE?
Authors: Dally William , Bartlett Brynna , Dean Camden , Scott Zachary
Published: September 2023

Based upon examination of beach profiles measured in June, 2016 (i.e. pre-Hurricane Matthew), November, 2016 (post-Matthew), and in September, 2017 (post Hurricane Irma) it was found that the 6.8 km of natural beaches in the Guana, Tolomato, Matanzas National Estuarine Research Reserve (GTM), extending from State range monuments R-46 to R-67 in St. Johns County, FL, experienced essentially no erosion of the primary dune, whereas dunes and bluffs in the developed beaches further south in St. Johns County were severely eroded and many beachfront homes experienced heavy damage
PROBABILISTIC PREDICTIONS OF EQUILIBRIUM RIPPLE GEOMETRY FOR TIME-DEPENDENT SEAFLOOR MODELING
Authors: Penko Allison M. , Phillip Ryan E.
Published: September 2023

We present a new equilibrium ripple predictor using a machine learning approach that outputs a probability distribution of wave-generated equilibrium wavelengths and statistics including an estimate of ripple height, the most probable ripple wavelength, and sediment and flow parameterizations. The Bayesian Optimal Model System (BOMS) is an ensemble machine learning system that combines two machine learning algorithms and two deterministic empirical ripple predictors with a Bayesian meta-learner to produce probabilistic wave-generated equilibrium ripple wavelength estimates in sandy locations.
DESIGN SCOUR LEVELS FOR DUNE REVETMENTS AND SEAWALLS
Authors: Nielsen Alexander
Published: September 2023

Particularly important for the design of dune revetments and seawalls subjected to breaking waves is the maximum depth of toe scour, the primary cause of failure of many coastal structures (Sutherland et al. 2006). Much of the published research on wave-induced toe scour has been under non-breaking waves with subaqueous seabed levels at the seawall/revetment toe. However, dune revetments and seawalls may become exposed to breaking waves for which this method has been derived. The method proposed herein assumes that the work done to excavate a scour hole is a function of the incident wave energy (Steetzel 1993), which incorporates wave period rather than wave height alone, and a formula for the toe scour level has been developed for a still water level datum at the wave breaking point. The formula has been calibrated with data derived from published laboratory studies covering a large range of scales, with some having been validated with prototype measurements.
SPH AND ANALYTICAL MODELING OF AN URBAN FLOATING STRUCTURE FOR COASTAL EXPANSION
Authors: Wang Shengzhe
Published: September 2023

The development of large-scale floating structures is recognized by the American Society of Civil Engineers as a critical step towards resilient coastal cities for climate change adaptation (ASCE, 2019). Yet, a lack of design guidelines acts to limit their development at the community scale. In response, we demonstrate and validate the applicability of a simplified analytical procedure against numerical solutions to elucidate the dynamics of a freely-floating pontoon-building system. This effectively presents a pathway towards the evaluation of structural requirements for the realization of floating cities as a sustainable alternative to traditional land reclamation.
WAVE INDUCED LOADS ON RECURVES ATOP A SEAWALL ON A SLOPED SEABED
Authors: Stagonas Dimitris , Gerald Muller
Published: September 2023

The current work adds on previous research and presents large scale experimental results of wave induced forces on a recurve atop a seawall at the end of a sloped approaching bed. In addition to the experimental results a theoretical expression for predicting the violent wave induced loads is also reported.
CONFINED-CREST IMPACT: THE INFLUENCE OF THE TOE BERM ON THE IMPULSIVE LOAD CONDITIONS
Authors: Castellino Myrta , Girolamo Paolo De , Monaci Viola , Romano Alessandro , Lara Javier L.
Published: September 2023

Composite vertical breakwaters are coastal structures used to defend port basins from waves in intermediate and deep water conditions. In order to safely use the inner side of harbors, it is important to limit wave overtopping. Parapet walls are used for this purpose. To improve the hydraulic efficiency of the parapet wall with a fixed crown wall height, the wall can be shaped giving rise to a recurved overhand toward the sea. Its function is to deflect back the incident waves. Recently, it has been shown that the interaction between non-breaking waves and recurved parapet can induce impulsive pressures due to the confinement of the incident wave crest deflected seaward by the overhanging structure. The new physical phenomenon has been called “Confined-Crest Impact (C-CI)” as shown by Castellino et al. 2018. This physical phenomenon can induce “unexpected” structural failure (Dermentzoglou et al., 2020). More recently, Castellino et al. (2021) extended the Goda’s formulae, which define the maximum pressures along a vertical breakwater, considering the “C-CI” induced by the presence of a recurved parapet. The conducted studies have concerned a vertical breakwater without any berm at the toe of the caisson. The purpose of this research is to extend this last work to a composite vertical breakwater based on a foundation berm.
EXPERIMENTAL AND NUMERICAL STUDY ON OBLIQUE WAVE-IN-DECK LOADS
Authors: Wang Hongchao , Santo Harrif
Published: September 2023

Most studies on wave-in-deck loads focus on head-on wave impingement whereas wave-in-deck loads due to waves incident from oblique directions are rarely reported. Numerical simulations for oblique wave-in-deck loads were presented in Iwanowski et al. (2002), Brodtkorb (2008) and Chen et al. (2018). However, in these studies, only numerical validations were performed against either two-dimensional experiments or empirical formulations due to a lack of experimental results. In light of this, we present the experimental results for wave impacts on a solid deck model due to a transient focused wave group incident from oblique direction in this study. The oblique experimental data is compared with the head-on counterpart by Santo et al, (2020) to investigate the incident wave angle effect on wave-in-deck loads. Numerical simulations are carried out to reproduce both the head-on and oblique wave-in-deck experiments using a three-dimensional (3D) numerical wave tank (NWT), and flow field information is interrogated to derive physical insights into complex wave-deck interactions. The solid deck model is a representative of a typical 2nd generation North Sea topside structures commonly exposed to severe winter weather. The configuration is also applicable to coastal structures such as bridges, piers, jetties or docks.
NUMERICAL STUDY ON THE INTERACTION BETWEEN PERIODIC WAVES AND A FLEXIBLE WALL
Authors: Hu Zhengyu , Li Yuzhu
Published: September 2023

Coastal structures were usually considered as stiff in the majority of studies related to wave structure interaction I n certain situations, such as impulsive wave loading on flexible breakwaters, ship hulls, tank walls hydroelasticity can be of importance for both wave dynamics and structural responses Akrish et al. (2018) showed that hydroelastic effects can either relax or amplify the hydrodynamic characteristics (i.e., wave run up and force) and structural oscillations in a deformable cantilever wal l interacting with an incident wave group. For flexible coastal defenses, Huang and Li (2022) showed that an elastic horizontal plate breakwater can exhibit a better performance of wave damping than a rigid one. Sree et al. (2021) experimentally investigated a submerged horizontal viscoelastic plate under surface waves. They reported a complete cutoff of the wave energy with the flexible plate. However, the hydroelasticity of a steep fronted structure in nonlinear progressive waves was not yet studied in a de tailed manner , which requires advanced numerical methods for modelling the nonlinear interaction between the fluid and the solid with finite deformations. The present study focus es on the hydroelastic behavior of a flexible vertical wall in nonlinear periodic waves with different wave periods (or frequencies )). The effects of the structural stiffness on the wave evolution and the structural deformation are investigated with a fully coupled wave structure interaction model.
SCOUR PROCESSES AROUND A COLUMN ON A SLOPED BEACH INDUCED BY BROKEN SOLITARY WAVES
Authors: Schendel Alexander , Schimmels Stefan , Welzel Mario , Quéré Philippe April Le , Nistor Ioan , Mohammadian Abdolmajid , Goseberg Nils , Krautwald Clemens , Stolle Jacob
Published: September 2023

Tsunamis continue to pose an existential threat to lives and infrastructure in many coastal areas around the world. Numerous studies have been conducted in recent decades to better understand the hazards and eventually mitigate risks resulting from tsunamis (Nouri et al., 2010; Palermo et al., 2013; Chock et al., 2013; Goseberg et al., 2013; Nistor et al., 2017; Stolle et al., 2018). One of these hazards is the emergence of deep scour holes around critical infrastructure and other buildings deemed community-essential, which affects their structural integrity and stability, rendering them unusable. Despite its importance, scour is still given limited and simplified consideration in foundation design guidelines related to tsunami hazards (ASCE-7 Chapter 6). This novel experimental study aims to improve the understanding of the time-variant scour process induced by single and consecutive broken solitary waves at large scale.
ON THE BEHAVIOR OF A TETHERED CYLINDER ARRAY UNDER IRREGULAR WAVES
Authors: Lorenzo Matteo , Pezzutto Paolo , Lillo Filippo De , Ruol Piero , Bosia Federico , Onorato Miguel
Published: September 2023

An interesting option for coastal wave attenuation can be provided by tethered floating breakwaters (see e.g. Agerton, 1976 and Seymour, 1979). This type of structure can be designed to be effective, while determining a very small impact on the environment (Dai, 2018). In principle, a regular lattice of reversed pendula (i.e. the breakwater) can be seen as an approximation to a mechanical metamaterial with interesting properties related to its periodic structure. The tethered floating breakwater we are studying has been designed as a finite lattice of submerged inverse pendula. The objective is to determine the efficiency of a regular two-dimensional lattice of spherical pendula. To isolate the one-dimensional behavior, a single array of reversed cylindrical pendula anchored to the bottom and excited by long crested waves has been tested.
CAN LIVING SEAWALLS BE DESIGNED TO IMPROVE BIOSECURITY?
Authors: Dafforn Katherine , Vozzo Maria , Fuchert Tegan , Mayer-Pinto Mariana , Bishop Melanie
Published: September 2023

Artificial structures such as seawalls, typically support less biodiversity than the natural habitats they replace and can harbour invasive species. Marine life that can survive on these structures are responding to several design factors including the material used in construction and availability of micro/macro habitats as well as local environmental conditions such as light and wave energy. Our understanding of how these factors might influence the types of marine life found on artificial structures is increasingly being used to restore native biodiversity by creating “living seawalls” in a practice commonly referred to as “ecological engineering” (Chapman and Underwood 2011, Dafforn et al. 2015). Given that more structures will be built to protect our coastal assets from climate change, there is an urgent need to scale up eco-engineering efforts.
EXTREME WAVES IN SHALLOW WATER AND DREDGED CHANNELS FOR DIRECTIONAL SEAS
Authors: Taylor David , Garber Sean , Collins Scott , Baker Scott , Cornett Andrew
Published: September 2023

Extreme wave conditions at coastal structures located offshore of natural coastlines and the zone of wave breaking are influenced by the deepwater wave conditions, the coastal bathymetry between deepwater and the structure, and the ongoing growth, generation and decay of waves across the coastal shelf. At locations where the coastal shelf is relatively flat, the gradually reducing water depths can limit the significant and maximum wave heights and crest elevations that may be encountered. If a coastal structure is located in deeper water than the bathymetry of approaching waves, for example port or navigation structures located in dredged channels or basins, coastal engineers need to consider wave conditions in the shallower approach waters and the transformation and propagation of waves across the dredged area. The directional characteristics of wave spectra in this situation can have a significant impact on extreme wave conditions that occur within the dredged basin. This paper presents insights into extreme wave conditions for gently sloping natural seabed profiles and also within a dredged basin, for directional seas which occur within the direct path of severe storms; for example, tropical cyclones.
EXPERIMENTAL WAKE DYNAMICS OF PILES WITH ARTIFICIAL BIOFOULING IN WAVES
Authors: Krautwald Clemens , Schweiger Constantin , Schürenkamp David , Goseberg Nils
Published: September 2023

Offshore structures become colonized by marine orga-nisms after a short period of time, whose common benthic communities depend among others on geographic location, water depth, water temperature, food supply, salinity and oxygen content of the water (Kröncke and Bergfeld, 2003; Shi et al., 2012). While biofouling can be categorized in biological terms as bivalves, kelp, algae, barnacles, tubeworms and other species (van der Stap et al., 2016; Wilhelmsson and Malm, 2008), engineers mostly distinguish between hard and soft marine growth based on the strength of their outer shell alone (Shi et al., 2012; Skaugset and Baarholm, 2008). Due to an increasing demand for sustainable energy, the offshore renewables industry experiences significant growth. However, many uncertainties persist in the consideration of biofouling, specifically when calculating loads accor-ding to the Morison concept, the influence of marine fouling on fatigue reassessment, on the flow velocities around cylinders and the vortex formation under waves. For the first time, the flow around cylinders with different artificial marine biofouling was recorded and analyzed in an extensive experimental study using a comprehensive 4D particle tracking velocimetry (PTV) system.
WAVE OVERTOPPING OVER A DIKE FOR VARIABLE WATER LEVEL
Authors: Streicher Maximilian , Pepi Yuri , Ricci Chiara , Franco Leopoldo , Bellotti Giorgio , Hughes Steven , Troch Peter
Published: September 2023

The still water level (SWL) during a storm is always dynamic (storm surge). The variability of the water level can be schematized as a time-varying hydrograph of a certain duration. The average wave overtopping discharge q is a function of the ratio between the freeboard Rc (the structure crest elevation above SWL) and the significant wave height Hm0. Since the variation during a storm of the SWL changes the freeboard Rc, the wave overtopping discharge is variable. Typically, in the laboratory the wave overtopping on coastal defense structures is investigated for a constant water level (CWL) and a pre‐determined structural exposure time frame. This exposure time frame is often representative for the storm surge peak or for a statistically representative number of individual waves (e.g. 1000 waves), not considering any variable water level (VWL). For the case of wave overtopping in VWL conditions, no validated prediction formulae exist (Kerpen et al. 2020) and the prediction is rather based on safe assumptions and engineering judgement. This research investigated the influence of a VWL on the prediction of the average wave overtopping discharge q.
APPLICATION OF SMOOTHED PARTICLE HYDRODYNAMICS ON A LOW LEVEL QUAY DECK
Authors: Alboom Wim Van , Altomare Corrado , Willems Marc , Vansompel Barbara , Devos Kristof , Lorente David Martinez , Verachtert Ramses
Published: September 2023

Rising sea water level projections challenge the existing levels within ports. Although air gaps have been a traditional means to avoid a fight with the force of the sea, such principle cannot be implemented easily in existing ports, or even for new projects, since these projects require interfacing with their surroundings. More and more, the interaction between the sea (and in particular extreme wave climates) and existing low quay deck levels for open types of quay walls has to be estimated. Apart from relying on physical model testing, the numerical world comes to our rescue. Significant advances have been made over the past decennium with the practical commercial implementation of smoothed particle hydrodynamics for practical engineering problems. This article describes a practical example of such an assessment for a particular project in the port of Ostend, Belgium.
IMPLICATIONS OF SECOND-ORDER WAVE GENERATION FOR USE IN WAVESTRUCUTRE RESPONSE EXPERIMENTS
Authors: Mortime William , Raby Alison , Antonini Alessandro , Greaves Deborah , Bremer Ton van den
Published: September 2023

Coastal communities and critical coastal assets are therefore increasingly reliant on engineered protection from wave-induced flooding. Dynamic wave force and wave run-up are among key design parameters of such protection. Present understanding of coastal wave-structure interactions and responses was gained through large databases of experimental data as well as numerical, and field measurements. It is well known that experimental data of wave-structure interaction are contaminated by second-order error waves at sub- and super-harmonic frequencies when first-order wave generation is used. The error waves arise from disparity between linear wave-maker signals and non-linear boundary conditions at the wave generator. Herein, we conduct a novel investigation by experiment of the implications of second-order wave generation for dynamic wave force and run-up on a vertical wall, in shallower depths than previously published (kd = 0.6 - 1.1). The implications of error waves on coastal responses is quantified through comparison of first-order generated (FOG) and secondorder generated (SOG) wave group experiments.
ANALYSIS ON FAILURE CAUSES OF DOCK DUE TO ABNORMAL WIND WAVES
Authors: Shim Kyu-Tae , Kim Kyu-Han , Shin Bum-Shick , Kim Hyun-Dong
Published: September 2023

In a coastal area where the water depth changes rapidly, waves developed in the offshore propagate to the coast, with a massive energy without any dissipation. Particular attention should be paid to the occurrence of damage in an island, where the land is open towards the ocean, in the event of abnormal wind wave, and design of structures in such region requires thorough examination. The southern and northern coasts of Hongdo Island located in the western coast of South Korea face the ocean side, and are directly affected when a typhoon or a high wave occurs. Therefore, structural damage due to wave generation frequently occurred in the coasts, and repair and reinforcement work were carried out several times.
OVERVIEW OF THE COASTAL TEXAS MEGA PROJECT
Authors: Das Himangshu S. , Burks-Copes Kelly , Thomas Robert C. , Maglio Coraggio , Williams Tony , Kerr Patrick C. , Sunstrum Nicole
Published: September 2023

The Texas Gulf coast is a complex system with numerous narrow inlets and broad back bays with intricate river and bayou networks. Due to its complex settings, the Texas coast is susceptible to extreme compound flooding due to fluvial, pluvial, and surge during hurricanes and tropical storms. Five of the top six largest tropical cyclone rainfall totals in the continental U.S. have occurred in Texas (USACE 2021a). The Texas coast is also one of the United States most dynamic regions in terms of population and economic growth. According to the Bureau of Economic Geology, twenty five percent of the population and thirty three percent of the economic resources of Texas are located along the 360 mile long coast. The objective of the Coastal Texas Study was to improve our capabilities to prepare for, resist, recover and adapt to extreme events. A “Multiple Lines of Defense” strategy was used in the Coastal Texas study to design cost-effective, environmentally friendly solutions that will reduce risks of storms impacting the coastal communities and restore important wildlife habitat at the same time.
COMPARISON OF NUMERICAL AND EMPIRICAL ESTIMATES OF WAVE CONDITIONS IN THE LEE OF A DETACHED BREAKWATER
Authors: Churchill Jim , Taylor David , Garber Sean
Published: September 2023

This paper presents a comparison of numerical and empirical methods routinely applied by practitioners to examine wave penetration in the lee of a breakwater, using a case study of a breakwater which is planned for Entrance Point, Broome in the northwest of Australia. Wave conditions representative of ambient and extreme conditions were determined from measured data captured directly offshore of the site, and an extreme cyclone metocean study (Baird, 2020). For ambient and extreme tropical cyclone conditions, waves are typically short crested at a peak period of between 4 seconds to 8 seconds. To examine the effectiveness of the offshore breakwater, empirical methods (Goda, 2000), a phase-averaged model (SWAN) and two phase-resolving model systems– the 2D Boussinesq wave model (MIKE21BW) and 3D non-hydrostatic model (MIKE3-Wave FM) - were applied.
DETACHED BREAKWATERS PROTECT LARGE MARINE INFRASTRUCTURE FROM SEVERE STORMS
Authors: Wehlitz Carl , Mabille Eugene
Published: September 2023

The port of Richards Bay in south Africa is constantly being subjected to extreme storm events where recorded wave heights exceed 5 m. Over the last decade, these storms have caused significant damage to the port’s breakwater structures, especially to the main southern breakwater. The frequency and intensity of large storms are increasing, and therefore much needed repairs to the aging infrastructure are becoming more frequent. As part of a campaign to enhance the structural integrity of the breakwaters at Richards Bay, the CSIR was contracted to undertake a 3D physical model study, which was completed in 2019. Subsequent to the 2019 study, the CSIR initiated a study to investigate alternative solutions that could potentially be implemented to safeguard marine infrastructure similar to the main breakwater at Richards Bay. This study focused on a submerged detached breakwater constructed in front of the existing main breakwater to shelter it from extreme storm events.
INVESTIGATING THE APPLICABILITY OF BOULDER/SAND SEDIMENT TRANSPORT MODELS FOR PORT RISK ASSESSMENT
Authors: Watanabe Masashi , Chua Constance Ting , Switzer Adam D.
Published: September 2023

Tsunami-induced damage to urban infrastructure is poorly constrained globally since tsunami are infrequent events and therefore, there are limited damage observations. Tsunami-borne debris can contribute significantly to structural damage. This issue is particularly prevalent in port areas, where containers, mobile equipment, and concrete objects can impact on structures. The modeling of boulder and sand sediment transport by tsunami could be used to model the transport of a variety of urban structures. In this study, we introduce various sand and sediment transport models and examine their accuracies. We conclude by proposing a model that is valid for the modelling of urban structures. Some of the findings in this work have already been reported in Watanabe et al. (2021; 2022) and readers are encouraged to refer to these publications.
FAILURE OF SEAWALLS DUE TO TSUNAMI-INDUCED SCOUR
Authors: Jayaratne Ravindra , Balasubramaniam Nilakshan , Kim Taeksang , Bricker Jeremy
Published: September 2023

The Indian Ocean tsunami in 2004 and the Tohoku tsunami in 2011 have shown that tsunami-induced scour is one of the primary reasons for the failure of coastal defence structures (Bricker et al., 2012; Jayaratne et al., 2016). In a coastal structure, scour can occur when the plunging jet impacts the landward toe of the structure, resulting in digging a hole around the foundation which eventually may destabilize the structure. This can be exacerbated by rapid drawdown induced liquefaction during the receding wave, and can lead to the failure of the structure. Therefore, accurate prediction of local and plunging scour is very vital in order to ensure the safety of the coastal structures under such conditions. Data we have at present are based on final or equilibrium scour depths, not the maximum scour depths. Survey teams measure scour profile once the extreme event is over. However, the trough or scour hole made can be partly filled by sediment transport from upstream (in the live bed case) or from sediment suspended within the scour hole that settles after the flow slows down. Thus, the scour depth survey teams measure are less than the actual maximum depths. Therefore, a novel experimental and numerical study is proposed to tackle this problem with the funding of the Royal Society, UK.
EFFECT OF TANDEM BREAKWATER ON PRESSURE REDUCTION ON VERTICAL SEAWALL
Authors: Nimma Rambabu , K Srineash V
Published: September 2023

There is an urgent need to develop methodologies to upgrade and retrofit existing coastal structures to retain their functionality in the scenario of changing climate. It is noticed that higher wave loads cause structural damage and increase wave overtopping rates, resulting in coastal flooding and inundation. Hard structures like seawalls can be reinforced by constructing a submerged breakwater in tandem with the seawall to adapt to the increased wave action due to climate change. Wave height attenuation, overtopping volume, and wave pressure or forces on structures are the important design parameters to be considered for the design of upgradation methods for coastal structures to withstand future climatic events. There are few works available in the literature focused on this direction. In the present study, we focus on pressure reduction on seawall due to the presence of a submerged breakwater in tandem with the seawall. Numerical simulations were carried out using a CFD-based numerical tool REEF3D to understand the effect of a submerged breakwater on wave pressure reduction on the seawall. The work also includes a validation study where the numerical results based on the present work are compared with the experimental studies from the literature.
LARGE EDDY SIMULATIONS OF BREAKING WAVE IMPACT ON A VERTICAL WALL ATTACHED WITH PARAPET
Authors: Ravindar Rajendran , Christou Aristos , Sriram Venkatachalam , Stoesser Thorsten
Published: September 2023

Wave return seawalls are structures designed to protect the leeward side from overtopping due to the action of waves. The numerical modelling of breaking waves on fully reflective structures like wave return seawalls are challenging due to the complex fluid dynamics involved, air-water mixture's interaction due to air entrapment and air entrainment and the dominant change in the ambient pressure as an effect of the hydrodynamic flow, which leads to compression and expansion of the air pocket. In this study, the vertical wall with parapet is considered since existing vertical walls are convenient to be retrofitted with such attachments to increase their efficiency in overtopping reduction. Very few numerical studies exist of violent breaking wave impacts on a vertical wall with parapets or curved structures, to the authors' knowledge. In addition, no direct numerical study discusses breaking wave impact on such structures and validated with experimental data.
PHYSICAL EXPERIMENTS ON OVERHANGING PARAPETS UNDER NON-BREAKING WAVE CONDITIONS
Authors: Antonini Alessandro , Dermentzoglou Dimitrios , Almeida Ermano de , Hofland Bas , Celli Daniele , Pasquali Davide , Risio Marcello di , Castellino Myrta , Paolo de Girolamo
Published: September 2023

The use of sea-wall and storm-wall structures within valuable landscape or urban areas often imposes rather restrictive limits in terms of structures height. A viable solution to address the safety against overtopping and the architectonical requirements is the use of recurved parapets. However, this type of structure is exposed to large impulsive loads that have been recently described and named as confined-crest impact, (C-CI), (Castellino et al., 2018) and caused several failures such as those in Strand (South Africa), Pico Island (Portugal) and Civitavecchia (Italy), (Castellino et al., 2021; Dermentzoglou et al., 2020; Martinelli et al., 2018). Accordingly, tools to properly design these curvilinear structures and to carry out comparative assessments between the induced advantage in terms of overtopping and increased structural complexity due to its shape and the C-CI are required. This work aims to identify practical design tools and provide benchmark data for the validation of the CFD model presented in the abstract n. 1643: “Castellino et al., Numerical experiments on overhanging parapets under non-breaking wave conditions”. A series of non-breaking regular and irregular waves experiments have been performed at the TU Delft Hydraulic Engineering Laboratory to investigate the contrasting behaviour of the overtopping phenomena and the exerted impulsive wave load on recurved parapets.
NUMERICAL EXPERIMENTS ON OVERHANGING PARAPETS UNDER NON-BREAKING WAVE CONDITIONS
Authors: Castellino Myrta , Antonini Alessandro , Celli Daniele , Dermentzoglou Dimitrios , Pasquali Davide , Risio Marcello Di , Girolamo Paolo De
Published: September 2023

Sea-wall and storm-wall structures aim to protect coastal areas and harbours from wave attacks. They are often located in the neighbours of city centres, that in turn impose rather severe visual limits affecting the maximum height of the structure. To combine the architectonical visual restrictions and the overtopping safety limits, imposed by different national standards, alternative solutions such as recurved parapet are often applied. Even for non-breaking wave conditions, these structures are subjected to large impulsive pressure that has been recently described and named as Confined-Crest impact, (C-CI, Castellino et al., 2018). The C-CI has been the cause of recent failures such as in the Civitavecchia harbour (Italy, Castellino et al., 2021 and Dermentzoglou et al., 2020). Accordingly, this phenomenon raised the attention of researchers and professionals who require an additional tool to design these curvilinear structures by considering the overtopping reduction performance, the structure complexity and the C-CI.