bluuebunny/crossref_metadata_2025 huggingface dataset:
APPLICABILITY OF D4PDF DATASET TO GLOBAL STOCHASTIC TROPICAL CYCLONE MODEL
Authors: Nakajo Sota , Umeda Jinji , Mori Nobuhito
Published: January 2021

Disaster damage caused by tropical cyclone has grown every year. However, our experience of tropical cyclone is not enough to evaluate very low frequent and catastrophic disaster event. Stochastic tropical cyclone model has been used for assessment of tropical cyclone disaster. Global stochastic model was improved by using a lot of ensemble Global Climate Model simulation data (d4PDF) instead of limited number of observation data. The model bias included d4PDF was corrected by each regional grid by simple statistical method and interpolation. The accuracy of new model was verified at representative regional area in different basins. Generally, the improvement is remarkable where tropical cyclones rarely passed. The variation of joint PDF of tropical cyclone change rate between previous model and present model agree with model improvement. As an example of application, the frequencies of strong tropical cyclone events of two cases were estimated.
EVALUATION OF HYDRAULIC PERFORMANCE OF WAVE DISSIPATING BLOCK USING POROSITY
Authors: Araki Susumu , Watanabe Daiki , Kubota Shin-ichi , Hashida Masaya
Published: January 2021

The reflection and transmission of wave dissipating work mainly depend on the shape and porosity of wave dissipating block. However, the influence of the shape and porosity of wave dissipating block on the reflection and transmission has not been investigated sufficiently. The purpose of this study is to investigate the influence of the porosity of wave dissipating block on the reflection and transmission coefficients through a series of hydraulic experiments where four kinds of wave dissipating blocks were used. Wave dissipating blocks with smaller porosity provided a larger reflection coefficient and a smaller transmission coefficient as a whole. However, a wave dissipating block provided a smaller reflection coefficient and a smaller transmission coefficient in spite of relatively larger porosity. The measured reflection and transmission coefficients were compared with those estimated by existing equations.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/lqyzabMw66U
WAVE OVERTOPPING TESTS TO DETERMINE TROPICAL GRASS SPECIES AND TOPSOILS FOR POLDER DIKES IN A TROPICAL COUNTRY
Authors: Meer Jentsje van der , Steendam Gosse Jan , Mosca Cesare A. , Guzzo Luca Bolatti , Takata Koichi , Cheong Ng Say , Eng Chua Kok , LJ Lionel Ang , Ling Goh Pei , Siang Chua Wee , Seng Chia Way , Karthikeyan M. , SC Francis Yap , Govindasamy Vivek
Published: January 2021

A dike or levee will protect a polder to build in a tropical country against coastal flooding. To ensure that the performance of the dike is in accordance with the safety standard, wave overtopping tests with a wave overtopping simulator have been performed on a mock-up dike. These wave overtopping tests will guide the selection of the grass species and topsoil for the grass cover of the landward side of the dike. The paper describes the design of a new dedicated wave overtopping simulator, the construction of the mock-up dike, the results of the eight tests on the mock-up dike and the critical velocities (strength indicator of the grass cover) established with the cumulative overload method.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/MCuKojNyNyQ
ADAPTATION WORKS TO AVOID THE FLOODING OF PIAZZA SAN MARCO (VENICE): PHYSICAL MODEL TESTS TO EVALUATE OVERTOPPING DISCHARGE
Authors: Martinelli Luca , Favaretto Chiara , Volpato Matteo , Ruol Piero
Published: January 2021

According to the management of the Mo.S.E. system, the water level in the Venetian lagoon is maintained below a certain threshold, that however does not guarantee the complete defense of the main Piazza. Flooding of the Piazza is presently tolerated, although limitedly to a minor extent, and can/will be avoided only thanks to additional adaptation works. One of the possible flooding mechanisms is the wave overtopping, and this note investigates the efficiency, as possible mitigation option, of a small temporary barrier placed along the S. Marco quay.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/wiSF2B81wIM
A CASE STUDY ON HARBOR OSCILLATIONS BY INFRAGRAVITY WAVES
Authors: Kwak Moon Su , Jeong Weon mu , Kobayashi Nobuhisa
Published: January 2021

In this study, the minimization of harbor oscillation using permeable breakwater was applied to the actual harbor and investigated a reduction effect by computer simulation in order to take into account the water quality problems and measures of harbor oscillation by infragravity waves at the same time. The study site is Mukho harbor located at east coast of Korea. The infragravity waves which obtained by analyzing the field data for five years focused on the distribution between wave periods of 40s and 70s and wave heights in less than 0.1m was 94percent of analyzing data. The target wave periods for minimization of harbor oscillation was 68s. The most effective method of minimization of harbor oscillation by infragravity waves was to install a detached permeable breakwater with transmission coefficient of 0.3 on the outside harbor and replace some area of the vertical wall with wave energy dissipating structure to achieve a reflectivity of 0.9 or less in a harbor. The reduction rate of amplitude shown in 27.4percent in this method.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/oDzrehaXlY8
ANALYSIS OF THE PERFORMANCE OF DIFFERENT SEDIMENT TRANSPORT FORMULATIONS IN NON-HYDROSTATIC XBEACH
Authors: Mancini Giulia , Briganti Riccardo , Ruffini Gioele , McCall Robert , Dodd Nicholas , Zhu Fangfang
Published: January 2021

Process-based, wave-resolving models are essential tools to resolve the complex hydro-morphodynamics in the swash zone. The open-source Non-Hydrostatic XBeach model can solve the depth-averaged wave-by-wave flow in the nearshore region up to the shoreline and the intra-wave bed changes during time-varying storms. However, validation and testing of its morphological response are still limited in the context of sandy beaches. This work aims to assess the performance of the wave-resolving sediment dynamics modelling within Non-Hydrostatic XBeach for different sediment transport formulations. The sediment transport modelling approaches considered in this study were tested and compared to laboratory experiments involving wave trains over an intermediate beach. Numerical results show a better performance in the prediction of the intra-swash sediment dynamics when the newly implemented wave resolving transport equation is applied compared to the existing approach within the model.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/2sy-Dr8iJ1M
A PROBABILISTIC APPROACH TO A COASTAL VULNERABILITY INDEX: A TOOL FOR COASTAL MANAGERS
Authors: Canul Roman , Mendoza Edgar , Silva Rodolfo
Published: January 2021

Vulnerability assessment is invaluable information for coastal managers to develop better coastal development plans. Two approaches to do so are presented here: one evaluates vulnerability from a deterministic view applying the analytical hierarchy process (AHP); the second uses a probabilistic approach based on the Latin Hypercube and Monte Carlo modeling, therefore it considers the probability distribution functions of the variables under analysis. The results show that a probabilistic approach is more suitable for the assessment of coastal vulnerability.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/WDbsVMYsnJs
CIRCULAR SHAPED ROUGHNESS ELEMENTS TO MITIGATE OVERTOPPING OF COASTAL REVETMENTS
Authors: Schoemaker Maarten , Mous Bart , Schlutter Flemming , Akkerman Gert Jan
Published: January 2021

This paper presents preliminary design guidelines for wave overtopping when circular-shaped roughness elements (ring-type revetment) are placed on the upper slope of a coastal revetment. Such a type of revetment was designed during the tendering phase of the Afsluitdijk reinforcement in 2017 as an innovative and highly effective way of reducing overtopping rates along coastal revetments. The design combines a relatively smooth lower slope (~1 in 2.5), wide storm berm (~1.5x wave height) and the roughened upper slope (~1 in 3) with a specific pattern of circular elements, resulting in a roughness comparable to that of a double layer rubble mound slope with an impermeable core. To effectively reduce overtopping rates, the circular elements require an average height of ~1/10 of the wave height and diameter of ~1/3 of the wave height, as well as a specific placement pattern (staggered pattern and spacing ~1/10 of the wave height).Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/EYxSI9ymYa4
QUANTIFYING THE INFLUENCE OF TRANSITIONS ON GRASS COVER EROSION BY OVERTOPPING WAVES
Authors: Warmink Jord , Bergeijk Vera van , Frankena Marc , Steeg Paul van , Hulscher Suzanne
Published: January 2021

Transitions in vegetated dike covers, such as geometry changes or roughness differences, are identified as weak spots in dikes for grass cover erosion by wave overtopping. Although several erosion models exist to model grass cover erosion on dikes, it is unclear how the effect of transitions on grass cover erosion must be included in these models. Therefore, we have developed a model approach to analyze the effects of transitions on grass cover erosion using field experimental data and to derive representative influence factors for one transition type. The model approach has been applied to the transition at the landward toe where the slope changes to a horizontal plane. The model approach is general applicable and can be transferred easily to other transitions. The derived factors can be used to improve predictions of dike cover erosion near transitions.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/YVH6PN4-Er0
WIND EFFECTS ON OVERTOPPING DISCHARGE AT COASTAL DEFENCES
Authors: Chowdhury S De , Zhou J. G. , Qian L. , Causon D. , Mingham C. , Pullen T. , Hu K , Russell M , Manson S , Stewart D , Wood M , Winter H , Joly A.
Published: January 2021

Wind effects on wave overtopping over fully impermeable vertical sea defence is studied in a shallow water flume based on a physical model for the Livermeade defence system. The investigation is mainly focused on impulse type wave interaction with the sea defence, when the overshooting jet is high during overtopping. We are able to identify distinct types of overtopping flows where moderate wind speed is not found to be affecting uniformly in all cases. We try to find explanation of this behaviours by studying the standing waves at the defence and complementary CFD simulations.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/byRz_N9zoXk
RECOVERY OF SANDY BEACH AFTER TYPHOON WAVES - CASE STUDY ON CHIGASAKI COAST
Authors: Ishikawa Toshinori , Uda Takaaki , Hosokawa Jun-ichi , San-nami Toshiro
Published: January 2021

Beach topography quickly changes in response to the action of storm waves, resulting in erosion of the foreshore with accretion under a calm wave condition after a storm. These seasonal beach changes may occur on beaches with protective measures or artificial beaches produced by beach nourishment. On these beaches, the shore protection function of a sandy beach is reduced when a trough is formed immediately offshore of the shoreline and the foreshore slope increases, indicating the importance of the study on topographic changes. Moreover, the time required for a beach recovery in response to wave conditions has not been sufficiently studied, along with the 3-D topographic changes associated with beach cycles. In this study, we aim to investigate these issues using the Narrow Multi-Beam survey data, wave data, and seabed materials data, taking the Chigasaki coast as an example. It was found that a seabed shallower than 2 and 3 m depths was eroded by rapid offshore sand transport during a storm event with the deposition of sand in a zone between 3 and 5 m depths, and then the beach recovered within 1-2 years after the storm. It was also confirmed that a bar and trough disappeared in 1-2 months under the conditions of HE = 0.5 m, TE = 8 s, and H/L = 0.005 when the crown depth of the bar was smaller than approximately 2 m. Thus, the topography after the storm waves recovers within several months or 1-2 years depending on wave conditions and the crown depth of the bar.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/W_P_3p_xd8U
EVIDENCE OF RESILIENCE IN REEF ISLANDS IN RESPONSE TO RISING SEA LEVEL ON HUVADHOO ATOLL, MALDIVES
Authors: Liang Christine Yiqing , Kench Paul S. , Ford Murray R. , East Holly K.
Published: January 2021

Reef islands are at the forefront of concern for future accelerating sea-level rise since their low-lying and isolated nature puts them at higher risk of marine inundation compared to continental coastlines. However, the perceived threat of complete submersion as implied by projected future sea-level rise and current island elevations do not consider the morphologically resilient nature of reef island systems. In particular, the role of sediment supply in the resilience of these islands is still relatively poorly studied. This study presents detailed descriptions of the sedimentary characteristics and stratigraphy of two lagoonal platform islands in Huvadhoo Atoll, Maldives, that formed during periods of Holocene sea-level rise. Island subsurface stratigraphy was reconstructed by analysing the skeletal composition and textural properties of 306 sediment samples from 37 cores extracted across the islands. Island sediments were dominated by coral sands with varied proportions of secondary constituents (molluscs, Halimeda, foraminifera, and crustose coralline algae). Downcore variations in composition show that the proportion of coral sands decrease with depth and the proportion of molluscs and Halimeda increase with depth (with the exception of cores that terminated on lagoon infill). The increased proportion of Halimeda and molluscs in these early island deposits may have resulted from the catch-up growth strategy of the reef during the mid-Holocene highstand as both organisms have high turnover rates and directly contribute to sediment production after death. The sedimentological response of increased Halimeda and molluscs highlights the resilient and dynamic nature of reef islands and the ability of reefs to adjust ecologically to changing sea levels.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/gy3zhqocMGw
NUMERICAL SIMULATIONS ON INFLUENCE OF LONG-TERM FLUCTUATION OF MEAN WATER LEVEL ON SAND WAVES IN THE KANMON WATERWAY, JAPAN
Authors: Yamagata Shiro , Orishikise Shouya , Yamashiro Masaru , Nakagawa Yasuyuki , Hashimoto Noriaki , Kukita Hiroki , Igata Hiromasa
Published: January 2021

In this study, the numerical simulation of tidal current and sediment transport in the Kanmon Waterway were performed by using a numerical simulation model FVCOM (Finite Volume Community Ocean Model (Chen et al. 2003)), in order to discuss the influence of the long-term fluctuation of mean water level on the sand waves. The numerical simulation results suggested that the spatial difference of the long-term fluctuation of mean water level in the Kanmon Straits slightly changes the tidal current around Tanoura Area, and consequently affects the development of sand waves.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/kfMfIVGiLKM
TOPOGRAPHIC RESPONSE TO EXTENSION OF AN OBLIQUE TRAINING JETTY AT IMAGIRE-GUCHI TIDAL INLET
Authors: Uda Takaaki , Ohashi Yutaka , San-nami Toshiro , Kainuma Seiji , Ishikawa Toshinori
Published: January 2021

At Imagire-guchi tidal inlet connecting Lake Hamana to the Pacific Ocean, a jetty had been extended by 1973 to stabilize the entrance channel of the inlet. Although 45 years has passed from the completion of the extension of the jetty to 2018, large topographic changes are still occurring offshore of the tidal inlet. One of the authors investigated the topographic changes until 2005, and the beach changes around the inlet were analyzed using the BG model (a model for predicting 3-D beach changes based on Bagnold's concept). In this study, topographic changes were analyzed again using the bathymetric survey data collected by 2017, and the development and deformation of the ebb tidal delta were studied.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/V1o3QXO-q1g
FORMATION OF CUSPATE FORELAND BEHIND AN ISLAND UNDER WAVES INCIDENT FROM TWO OPPOSING DIRECTIONS
Authors: Kobayashi Akio , Uda Takaaki , Yokota Takuya , Noshi Yasuhito , Nishimura Kazuma
Published: January 2021

Long-term shoreline changes of a cuspate foreland behind Okinoshima Island located in Tateyama Bay were investigated, and a beach survey was carried out using an RTK-GPS on May 2, 2018. Then, numerical simulation of the formation and deformation of a cuspate foreland between 1941 and 2012 was carried out using the BG model (a model for predicting 3-D beach changes based on Bagnold's concept). It was found that sand, which was deposited on the shallow sea associated with the increase in ground level during the Kanto Great Earthquake that occurred in 1923, accumulated to form a cuspate foreland.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/4SDfN9xp9hE
A NATURE-BASED SOLUTION FOR SUSTAINABLE PORT DEVELOPMENT IN PORT OF KUALA TANJUNG, INDONESIA
Authors: Taneja Poonam , Hoek Alexander van der , Koningsveld Mark van
Published: January 2021

The Building with Nature (BwN) approach developed by Ecoshape suggests that nature-based solutions can be sustainable and cost-effective alternatives for traditional engineering solutions. Widening the solution space by studying and understanding the physical and ecological system in the early stages of port planning and design is more likely to result in sustainable ports with opportunities for multi-functionality and respect for nature. This paper applies the BwN philosophy to a case study, i.e., the ongoing port development in Kuala Tanjung in Indonesia and examines the technical and financial feasibility of a nature-based concept, i.e., a mangrove breakwater instead of a traditional 'hard' breakwater. Mangroves can realize significant wave attenuation, and at the same time, they are productive eco-systems that can result in long-term benefits through multifunctional land use. A berm built of dredged material with a mild slope which 'grows' naturally by accretion behind permeable dams can create the right conditions for mangrove trees to grow. This mangrove protection can develop into a sustainable barrier which grows with the (relative) sea level rise by trapping sediments. A preliminary design was made on the basis of information available in literature. A rough cost comparison considering only the supply and placing of fill material showed that mangrove breakwater is about 25percent more expensive than a hard breakwater for the case under study. In view of the numerous port projects being planned in Indonesia, the technical and financial feasibility of mangrove breakwaters that can also enhance nature create added value for the surroundings is a promising finding.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/Rr8P8G1GjgM
MODELLING OF WAVE OVERTOPPING FLOW OVER COMPLEX DIKE GEOMETRIES: CASE STUDY OF THE AFSLUITDIJK
Authors: Bergeijk Vera van , Warmink Jord , Hulscher Suzanne
Published: January 2021

Grass cover erosion by overtopping waves is one of the main failure mechanisms of dikes. Transitions in cover type and geometry can increase the hydraulic load and are therefore identified as vulnerable locations for grass cover erosion. Two models are applied to the inner slope of the Afsluitdijk in the Netherlands to show how transitions can be included in overtopping models. Firstly, the analytical grass-erosion model is used to simulate the erosion depth along the profile for a six-hour storm. The model results show that the erosion depth is maximal at the end of the two slopes in the profile. Secondly, the effect of transitions on the hydraulic load is computed with a detailed hydrodynamic model. The model results show that geometric transitions significantly influence the shear stress, the normal stress and the pressure. Four vulnerable locations for grass cover erosion are identified based on the model results that are related to slope changes along the profile. Furthermore, the model results show that the overtopping flow is mainly affected by geometric transitions, while no effect of roughness transitions on the modelled forces was observed.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/t1cPJwf72nE
THE ROLE OF GEOTEXTILE TUBE AS LOW-CRESTED BREAKWATERS IN RESTORING SEVERE BEACH EROSION PROBLEM AT PEBUAHAN BEACH IN BALI ISLAND
Authors: Sulaiman Dede , Hidayat Hendra
Published: January 2021

Pebuahan Beach in Jembrana Regency, Bali has experienced severe beach erosion since the construction of the Nusantara Pengambengan fishing port, 10 km east of Pebuahan. Efforts to countermeasure the coastal problem has been carried out by many local residents, but failed due to strong longshore drift. Through a collaboration between the Research Center for Water Resources, the Bali Penida River Basin, and PT. Geotechnical Systemindo, the implementation of low-crested breakwaters (LCB) or PEGAR, made of Woven Geotextile Tubes was initiated. Four woven geotextile tubes C12.9 m with length varied from 20 m to 25 m were installed to form LCB with the length of 60 m, at distance to the coast of 50 m. The monitoring of shoreline changes was conducted over the 3 months after its installation, which shows the formation of a new shoreline with the amount of deposited sand of 185.8 m3. The breaking wave on LCB crest results in successfully controlling the longshore current, hence the longshore drift settles behind the LCB to form a new coastline. It is expected this field study can be treated as an additional input to improve LCB Guideline and to expand LCB effectiveness scope not only apply to shallow wave conditions and beaches such as on North coast of Java, but also can be applied more universally to a deeper coastal waters with high wave conditions.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/AFzvkvYY2Do
SEDIMENT TRANSPORT FIELD DATA AND NUMERICAL MODELING STUDY TO SUPPORT DREDGE PIT INFILL RATE ESTIMATES
Authors: Bayram Atilla , O'Neil Sean , Zhang Yang
Published: January 2021

Site specific bedload and suspended sediment transport data collected at two test pit locations over a four-day period during April 2015 were analyzed to calibrate a numerical sediment transport model of Cook Inlet, AK. The field data campaign was designed to collect suspended load and bedload field measurements and was carried out in two phases. During Phase 1, both suspended load and bedload measurements were taken at approximately 55 ft water depth. The suspended sediment concentration was observed to be nearly uniform over the water column. Laboratory analysis showed the suspended sediment had an effective grain size of approximately 0.03 mm with 0.005 mm within a 95percent confidence interval. During Phase 2, hydrodynamic, suspended load and bedload measurements were collected over four tidal cycles in the surfzone. A two-dimensional sediment transport model was developed to simulate sediment transport infill rates at the dredged areas of the Project site. The model was calibrated by comparing measured suspended load measurements made at two offshore locations. Calibration results showed that the suspended load transport rate, which is the dominant sediment transport regime in the area, can be predicted accurately at the project site. Based on the calibrated sediment transport model, preliminary annual sediment infill rates were estimated to lie between 1.1 to 1.6 ft/yr at offshore and nearshore locations, respectively, for the presently observed and measured conditions.
HYDRODYNAMIC AND WATER QUALITY MODELLING IN SYDNEY HARBOUR
Authors: Tillman Pei , Dixon Jonathan , Wang Yue-Cong , Griffith Merran
Published: January 2021

The Sydney Harbour waterway modelling suite examines the changes in water quality in the harbour estuary and its tributaries associated with stormwater runoff and wet weather sewage overflows from the upstream catchments, in Sydney Australia. This paper discusses the development and performance of the numerical models. The models have been used to investigate the spatial variability of catchment pollutant loads and the impacts of sewer overflows on the water quality in the Sydney Harbour estuary. The scenario modelling results demonstrate that sewer overflows have a minimal impact on the Sydney Harbour estuary water quality, with stormwater dominating most changes in water quality.
HOMOGENEOUS LOW-CRESTED STRUCTURES FOR BEACH PROTECTION IN CORAL REEF AREAS
Authors: Medina Josep R. , Gomez-Martin M. Esther , Mares-Nasarre Patricia , Escudero Mireille , Oderiz Itxaso , Mendoza Edgar , Silva Rodolfo
Published: January 2021

In many countries, the health of the marine ecosystems and the sun-sand-sea tourism depend on the coral reefs, which have been retreating around the world during the last decades. Homogeneous Low-Crested Structures (HLCS), made of large rocks or pre-cast concrete units, can be placed to mimic the functions of beach protection and eventually serve as a refuge for species. HLCS is a type of multi-purpose green infrastructure which is functionally similar to conventional low-crested structures but have higher porosity and are more easily dismantled for re-use. Contrary to conventional low-crested structures, the functionality of HLCS protecting beaches depends on the selected placement grid; this paper describes physical and numerical placement tests on horizontal bottom used to characterize the layers coefficients of Cubipod HLCS. The Bullet Physic Engine (BPE) numerical model used in the gaming industry, which is based on the rigid body method, is calibrated using the physical placement tests. The layer coefficients of Cubipod HLCS measured in the physical placement tests were similar to those obtained with the BPE numerical model, which could be used to optimize placement grids of HLCS on specific sea bottom conditions. Finally, the influence of the placement grid of Cubipod HLCS on the structure height, crest freeboard and wave transmission is analyzed.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/5bi-jpuJYcQ
A METHOD FOR EVALUATING TSUNAMI LOADING ON SEAWALLS DURING OVERFLOW
Authors: Toriyama Takuya , Ishida Nobuo
Published: January 2021

Seawall constructions are one of the main ways of protecting coasts against tsunamis. The estimation of tsunami loading on a structure is important for evaluating the fragility of seawalls. In this study, hydraulic flume tests were conducted to investigate the characteristics of tsunami loading when tsunamis flow over seawalls. Correlations between the loading on seawalls and the specific energy of the flow are investigated. A method for evaluating the maximum tsunami loading on the seawall is proposed. The approach can evaluate the maximum tsunami loading, even when tsunamis flow over seawalls.
EFFECT OF THE DENSITY OF INUNDATION WATER ON TSUNAMI RUN-UP
Authors: Matsutomi Hideo
Published: January 2021

Aiming for the advancement of historical and/or prospective tsunami scale evaluations, and focusing on the tsunami run-up, series solutions to the tip position a(t), velocity U (=da/dt) and acceleration d2a/dt2 in the tip region of inundation flow (unsteady flow) with sediment over a uniformly sloping bottom under the condition that the friction factor K is not linked to the density of inundation water, and analytical solutions to a(t), U(t), d2a/dt2, the maximum run-up distance a_m and height Rm under the condition that K is linked to density are derived, and effects of density on them and run-up process are theoretically examined. It is indicated that (1) in the run-up analysis (including numerical simulation) of tsunami with sediment under the condition of a constant K, even if a_m and Rm can be predicted accurately, there is a possibility of evaluating the run-up duration time inaccurately and vice versa, and (2) linking K to density is necessary to solve this matter. An expression for the relationship between K and is also presented. Moreover, it is verified that the derived series and analytical solutions are useful to discuss the effects of density on the run-up of tsunami with sediment through a comparison between the experimental and theoretical maximum run-up distances.
MICROPLASTICS TRANSPORT AND MIXING MECHANISMS IN THE NEARSHORE REGION
Authors: Abolfathi Soroush , Cook Sarah , Yeganeh-Bakhtiary Abbas , Borzooei Sina , Pearson Jonathan
Published: January 2021

Microplastics (MP) are emerging pollutants in the marine environment with potential ecotoxicological effects on littoral and coastal ecosystems. A dominate contributing source of microplastic particles is the fragmentation of macroplastics from manufactured goods, alongside laundered synthetic material, abrasion of vehicle tyres and personal care products. The indiscriminate use of plastic and poor management of plastic waste pose serious threat to ecosystem functionality and resilience. Understanding the key underlying transport and mixing mechanisms which influence the behavior of microplastics and their environmental fate are crucial for identify potential microplastic fate-transport pathways from source to sink. This is fundamental for evaluating microplastic interactions and impact on ecosystems. This paper presents laboratory-based tracer measurements for solute and polyethylene (PE) microplastics in the presence of waves. The tests were undertaken in a wave tank equipped with an active absorption paddle-type wave-maker. Fluorescent dye was used to stain the PE particles using a novel staining technique. Rhodamine dye was used as a proxy for the transport of solute pollutants. The temporal and spatial behavior of both microplastics and solute across the nearshore zone was measured using submersible fiber optic fluorometers. Hydrodynamic conditions were designed to create monochromatic waves with a range of wave steepness Sop = 2 - 5 percent. Tracer measurements were conducted at three locations, seaward of the breaker region, breaker region and inner surf zone to provide a comprehensive understanding of mixing across the nearshore. The dispersion coefficients were determined for both solute and PE particles. The results indicate the dominant role of surface and bed generated turbulence in determining mixing and dispersion influenced by wave breaker type and width of the surf zone. The comparison of tracer data suggests that PE particles, with similar density to water, and the solute tracer have a similar transport and mixing behavior under the influence of waves.
STABILITY OF SMALL BARRIER ESTUARIES: FIRST PASS ASSESSMENT USING PUBLIC DATA AND ATTRACTOR MODELLING
Authors: Hinwood Jon , McLean Errol
Published: January 2021

Small barrier estuaries are common in temperate latitudes where catchment runoff is small. The entrance state controls the tidal exchange and hence the salinity regime and flushing. To aid the study and management of these estuaries, predictions of the stability and future evolution of the estuary entrance must be made. This paper demonstrates the application of the attractor method to determine the stability of a wide sample of estuaries on the south-eastern coast of Australia, using only data available in broad-based public data bases. The method uses a simple hydrodynamic-sediment balance model, run for thousands of scenarios and thousands of tide cycles to identify the long-term dynamic equilibria - the attractors. The model predictions are shown to match stability data in the data bases and to provide realistic predictions of the entrance evolution. The results have direct applicability to high-level assessment of coastal assets and to optimal selection of model scenarios for more detailed modelling of any selected estuary.
USE OF REMOTE SENSING TECHNIQUES AND NUMERICAL MODELLING TO PREDICT COASTAL EROSION IN VIETNAM
Authors: Sokolewicz Marius , Bergsma Laura , Schemmekes Loek , Nguyen Hoan , Boersen Stef
Published: January 2021

Accurate prediction of coastal erosion is of importance for the investment planning of measures enhancing resilience to natural hazards. Field data on historical is generally lacking. Recent advances in deriving historical shoreline position from freely available satellite images combined with numerical modelling of shoreline erosion provide a reliable method for prediction of coastal erosion. This paper discusses the available tools and presents their application in a study case in Quang Ngai City, Vietnam.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/oOk9-bmDorA
WAVE LOADS ON A NAVIGATION LOCK SLIDING GATE: NON-LINEAR EFFECTS
Authors: Cavallaro Luca , Iuppa Claudio , Musumeci Rosaria Ester , Scandura Pietro , Foti Enrico
Published: January 2021

The wave loads on a navigation lock gate provided with an opening in the ballast tank are analyzed using a mathematical model based on the linear wave theory and the numerical integration of the Navier-Stokes Equation. The analysis focuses on the evaluation of the non-linear effect influence on the vertical load on the gate. It is shown that the numerical and analytical models agree on the identification of the value of the wave number at which the maximum value of the dimensionless vertical force on the gate is detected. However the analytical model overestimates the peak value of the vertical load with respect to the CFD simulation. To fill this gap, in this paper an easy to use procedure is developed which allows to correct the results of the analytical model.
COASTAL FLOODING RISK ASSESSMENT BY A NEURAL NETWORK APPROACH
Authors: Iuppa Claudio , Cavallaro Luca , Musumeci Rosaria Ester , Foti Enrico
Published: January 2021

An effective system of coastal flooding forecasting in the case of storm is essential to mitigate coastal risks for the population living in low-land coastal zones (less than 10 m above MSL). Nowadays, predictions of coastal flooding are usually carried out by adopting nested numerical models. However, the models adopted to obtain the data in the nearshore area require high computational costs, which are often too demanding and not viable for large scale forecasting. Data-driven models, such as Artificial Neural Networks (ANNs) can help to solve the problem as they can map complex nonlinear relationships between input and output variables once a suitable dataset of process realizations is available. In the present study a forecasting model for coastal flooding based on ANNs, in which the input data are the offshore wave characteristics from large scale model and the output results are the flooded areas, is proposed. These outputs provided a straightforward prediction of the area interested by coastal flooding during storms. Here an application of the model to assess the flooding risk in the village of Granelli, in the Southeast of Sicily (Italy) is presented.
NEURAL NETWORK MODEL FOR IDENTIFYING THE COASTAL SAND AREA USING THE AERIAL PHOTOGRAPHS PICTURED BY UAV
Authors: Sato Daisaku
Published: January 2021

Small island states formed by atolls such as Marshall Islands, Kiribati and Tuvalu require useful and efficiency method of coastal monitoring for coastal management because of lack of human resources and budget. In atoll islands, the identification of shape of sandy beach and temporally accumulation area of sand has high importance in coastal management. In this study, neural network model to classify the aerial photographs pictured by UAV was established for identifying the sand area in the coastal zone of Fongafale island in Funafuti atoll, Tuvalu. Photographs of coastal sediments especially sand, in Fongafale island were collected by digital camera. These photographs were used to make the data set for training and testing of the constructed neural network model. Additionally, aerial photographs pictured by UAV were collected to apply to the constructed neural network model. In this study the convolution neural network was constructed to classify the aerial photographs.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/trHQOmsFpD4
DO WE NEED PRE-STORM SURVEYED BATHYMETRY FOR OPERATIONAL EROSION FORECASTING? EVALUATION OF REPRESENTATIVE AND SYNTHETIC BATHYMETRY ALTERNATIVES
Authors: Matheen Nashwan , Harley Mitchell D. , L.Turner Ian , Simmons Joshua A. , Thran Mandi
Published: January 2021

Immediate pre-storm bathymetry is a key input required for numerical models used in coastal hazard Early Warning Systems. However, the expense and challenging nature of hydrographic surveying means that the availability of high-quality data is extremely rare. This study evaluates the extent to which synthetic and representative bathymetry alternatives can be used to obtain reliable predictions of storm induced sub-aerial erosion using the XBeach coastal erosion numerical model. Multiple storm events at 2 contrasting sites are modelled using 6 bathymetry scenarios including pre-storm surveyed bathymetries, an average bathymetry, and Dean profiles. The output is analysed to evaluate the skill of XBeach erosion predictions as a function of the bathymetry used.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/bE3aXVXxZqQ
CROSS-SHORE SEDIMENT TRANSPORT IN THE SWASH ZONE: LARGE-SCALE LABORATORY EXPERIMENTS
Authors: Antonio Sara Dionisio , Werf Jebbe van der , Vermeulen Bart , Caceres Ivan , Alsina Jose M. , Larner Michael , Puleo Jack , Zanden Joep van der , Hulscher Suzanne
Published: January 2021

The swash zone is a highly dynamic boundary between the beach and the surf zone. Swash processes determine whether sediment is either stored on the upper beach or is transported offshore, and thus strongly affect shoreline evolution. The present research focuses on the hydrodynamics, sand transport processes and net sediment transport in the swash zone through a series of large-scale wave flume experiments. This research aims to improve the understanding of swash zone sand transport processes, in particular the role of cross-shore sand advection and wave-swash interactions, and bring new detailed insights into the relation between intra-swash processes and net sand transport rates.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/tYvJ0pML-kU
THE EFFECT OF BUILDING GEOMETRY ON AEOLIAN DEPOSITION AND EROSION PATTERNS: A FIELD EXPERIMENT
Authors: Poppema Daan , Wijnberg Kathelijne , Mulder Jan , Hulscher Suzanne
Published: January 2021

Buildings at the beach-dune interface, such as restaurants and (holiday) houses, affect wind-driven sand transport in their surroundings. Hereby they shape the development of the beach-dune system. This can have implications for the flood protection offered by dunes. Therefore, this research aims to understand the effect of buildings at the beach-dune interface on beach-dune morphology. In this contribution we present the results of a field experiment which focused on the effect of building size and geometry on the size and location of the deposition patterns directly around buildings.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/hlcMP7Ev1m0
UNDERSTANDING SURF-ZONE HYDRO-MORPHODYNAMIC PROCESSES IN A TYPICAL POCKET BEACH ALONG THE WEST COAST OF INDIA
Authors: Jeyaraj Satheeshkumar , Ramakrishnan Balaji
Published: January 2021

Coastal processes are natural processes that operate along coastal zones, resulting in morphological changes in erosion and deposition. The western coast of India is affected by extreme monsoonal wave activity, which can lead to the loss of beaches and the vulnerability of the dunes. As a result, understanding actual near-shore physics and long-shore sediment transport becomes a prerequisite for the development of an effective coastal zone management strategy. The aim of this study is to quantify and investigate longshore sediment flux as a result of wave action based on sediment trap experiments (Kraus 1987). The Kraus (1987) method, along with wave hydrodynamics and current measurements, is performed using acoustic instruments across the surf zone.
CROSS-SHORE MODEL APPLICATION TO HASAKI BEACH, JAPAN: EVALUATION OF PARAMETER SETTING
Authors: Kato Koshi , Udo Keiko
Published: January 2021

Japan's coasts is being suffered by significant erosion. There is already a high demand to protect coasts from the erosion but climate change threatens further erosion. Udo and Takeda (2017) projected future beach loss in Japan due to sea-level rise using Bruun rule. However, its restrictive assumption that they probably do not exist in nature makes difficult to assess uncertainties of the projection results. In this paper, Cross-shore (CS) model developed by Larson et al. (2016), which is more realistic model considering the cross-shore sediment exchange, is applied to calibrate the parameter settings at Hasaki beach in Japan, and model applicability was evaluated.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/sOFr9Jb5a_s
OBSERVATION AND MODELLING OF SHOREWARD PROPAGATING ACCRETIONARY WAVES (SPAWS) ON MICROTIDAL BEACHES
Authors: Bouvier Clement , Korteling Jelmer , Price Timothy D. , Balouin Yann , Castelle Bruno
Published: January 2021

At straight sandy coasts, wave-induced processes often lead to intriguing alongshore-variable morphology on spatial scales from 10s - 1000s of meters. Observations have shown that the horns of crescentic bars may separate from the bar during storms and subsequently migrate onshore towards the beach during calmer periods as a spatially coherent structure, termed Shoreward Propagating Accretionary Wave, or SPAW. Here, we aim to (1) quantify the morphological evolution of a SPAW and (2) unravel the physical processes underlying its onshore migration and spatial coherence. To do so, we studied onshore migration of a SPAW using a process-based morphodynamic model.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/5P22G_S0FJM
MORPHOLOGICAL EVOLUTION OF A STABILIZED TIDAL INLET AND IMPLICATIONS FOR COASTAL INFRASTRUCTURE VULNERABILITY
Authors: Velasquez-Montoya Liliana , Overton Margery F. , Sciaudone Elizabeth J. , Dunn Michael
Published: January 2021

Evolutionary patterns of a tidal inlet and its adjacent barrier islands are identified via 10 years of remotely sensed data, hydrographic surveys, and a morphological numerical model. A cyclical geometric adjustment of the inlet to dredging of its navigation channel indicates that the system is in stable equilibrium. The inlet has been experiencing a counterclockwise rotation likely caused by the growth of a spit and the presence of a terminal groin that restricts the inlet migration. As this rotation continues, the southernmost flood channel has been encroaching into the downdrift back barrier. Continued erosion along the estuarine shoreline could increase the vulnerability of an existing coastal roadway from the estuarine side.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/DCee7MlQkGI
OVERALL EROSION OF THE YANGTZE RIVER DELTA UNDER HUMAN INTERVENTIONS: SPATIAL PATTERNS AND SEDIMENT BUDGET
Authors: Luan Hualong , Qu Geng , Chai Zhaohui , Yao Shiming
Published: January 2021

River deltas are actively propagating systems as redundant fluvial sediment accumulated hereon after part of the amount being taken away by marine currents. Anthropogenic activities in drainage basins strongly modified such propagation processes by increasing sediment productions over the past millennia and decreasing sediment loads in the past century. The most significant feature is the delta erosion or flooding as a result of sediment trapping in upstream reservoirs in combination with relative sea-level rise. In addition, human interventions within deltaic regions may complicate the morphological patterns with strong spatial variations. Understanding the controlling factors and future trends of delta erosion is of high importance for sustainable development and comprehensive protection of these dense-populated areas.
SIMULATION OF LONG-TERM SHORELINE CHANGE DRIVEN BY LONGSHORE AND CROSS-SHORE SEDIMENT TRANSPORT
Authors: Ding Yan , Kim Sung-Chan , Styles Richard B. , Permenter Rusty L.
Published: January 2021

Driven by wave and current, sediment transport alongshore and cross-shore induces shoreline changes in coasts. Estimated by breaking wave energy flux, longshore sediment transport in littoral zone has been studied for decades. Cross-shore sediment transport can be significant in a gentle-slope beach and a barred coast due to bar migration. Short-term beach profile evolution (typically for a few days or weeks) has been successfully simulated by reconstructing nonlinear wave shape in nearshore zone (e.g. Hsu et al 2006, Fernandez-Mora et al. 2015). However, it is still lack of knowledge on the relationship between cross-shore sediment transport and long-term shoreline evolution. Based on the methodology of beach profile evolution modeling, a semi-empirical closure model is developed for estimating phase-average net cross-shore sediment transport rate induced by waves, currents, and gravity. This model has been implemented into GenCade, the USACE shoreline evolution model.
MORPHOLOGICAL HYSTERESIS OF ARTIFICIAL BEACH UNDER LARGE WAVE CONDITION: AN EXPERIMENTAL INVESTIGATION
Authors: Li Yuan , Zhang Chi
Published: January 2021

Submerged Artificial sandBars (SAB) are usually implemented on the lower shoreface to protect berms or dunes during storm surges. The lee-effect of SAB is due to its ability in triggering large wave breaking, so that sediment concentration in water column and sediment transport capacity will decrease in the covered areas. Previous studies analyzed the lee-effect and topography evolution of SAB, however the morphological coupling of SAB and natural profiles is seldom referred. In this study, the morphological coupling between SAB located on the lower shoreface and the berm in upper beach is investigated in a well-controlled physical experiment.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/KsOK30StZZQ
ALLOWANCE FOR FORMATION OF MEGA SAND WAVES ON THE SEABED IN THE DESIGN OF FAIRWAYS IN ESTUARIES WITH STRONG CURRENTS
Authors: Molen Wim van der , Watson Holly , Taylor David
Published: January 2021

The declared depth in port access channels is often maintained by dredging and monitored by regular bathymetric surveys. However, at remote sites these activities are not cost-effective and the channel depth would need to be defined based on the surveyed depth plus an allowance for sedimentation and variability in bed levels. This allowance can especially be significant in estuaries with strong tidal currents, where mega bedforms, including sand waves, develop on the seabed due to the prevailing strong current flows. The mega sand waves are highly mobile and fluctuate in height as they migrate over the seabed. Mega sand waves and mega ripples with a height up to approx. 3.2 m were observed in multi-beam bathymetric survey undertaken in the offshore entrance to the Geba River estuary in Guinea Bissau. Supramax bulk carriers with a draft of 11-12 m are planned to transit this area on departure from a proposed phosphate export terminal located further upstream in the estuary.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/5Gmy9yQkfno