Arnold van Rooijen

University of Western Australia | UWA · Oceans Graduate School

The physical roughness (canopies) formed by organisms within aquatic ecosystems (e.g., seagrass, kelp, mangroves, etc.) modifies the local wave-driven hydrodynamics within coastal and estuarine regions. In wave-dominated environments, an understanding of the mean wave-driven flows generated within and above canopies is important, as it governs mate...

Nature-based methods use the creation or restoration of coastal habitats for hazard risk reduction. This can be done through restoring the habitat alone (“soft” approach), or in combination with hard structures that support habitat establishment (“hybrid” approaches). The need to develop, test and apply more sustainable techniques to mitigate the i...

Coastal canopies formed by aquatic vegetation can significantly modify nearshore wave processes, which has motivated numerous laboratory and field studies investigating how wave attenuation occurs for a wide range of canopies as a function of wave conditions and canopy properties. To predict wave dissipation by canopies, numerous formulations have...

Prior to construction, coastal structures are often tested in wave flumes and basins using physical models to assess performance and stability. To ensure that such testing provides a reasonable representation of design conditions, it is crucial to generate realistic wave conditions that occur in the field. Wavemaker capabilities such as second-orde...

Saltmarshes are increasingly recognised an important asset in coastal management as they dissipate wave energy and thus reduce the potential for coastal flooding. The frontal surface area (FSA) and the drag coefficient (Cd) are parameters commonly used in wave attenuation models to express the resistance of vegetation structure to incident waves. T...

Currents can affect the evolution of waves in nearshore regions through altering their wavenumber and amplitude. Including the effect of ambient currents (e.g., tidal and wind-driven) on waves in phase-resolving wave models is not straightforward as it requires appropriate boundary conditions in combination with a large domain size and long simulat...

Mangrove vegetation constitutes a natural coastal defence against waves and erosion. Despite their protective role, mangrove ecosystems have experienced continuous degradation over the last decades due to human causes. At retreating mangrove coastlines, bamboo structures are built to create new habitat for mangrove colonization. Existing structures...

Uma das consequências da elevação do nível do mar é predispor a população e o ecossistema à inundação costeira. A vulnerabilidade pode causar distintos impactos dependendo da cota do terreno e da extensão da área ocupada. Imbé e Tramandaí localizados no litoral norte do RS são dois municípios que apresentam cotas baixas e áreas densamente ocupadas....

Large parts of the Australian coastline are surrounded by nearshore aquatic vegetation, such as kelp or seagrass. Although it is widely accepted that vegetation plays an important role in dissipating wave energy and reducing current magnitudes, there is a limited understanding on how this affects coastal morphology. Consequently, most coastal model...

A laboratory experiment was conducted to investigate how a bimodal spectrum of high-frequency (sea-swell) and low-frequency (infragravity and seiching) waves affect the shape of a shoreline profile adjacent to a reef. The experiments were conducted in a 55 m wave flume, using a 1:15 scale fringing reef model that had a 1:5 forereef slope, a 14 m lo...

Canopies formed by aquatic vegetation, such as seagrass meadows and mangroves, introduce substantial spatial heterogeneity in nearshore hydrodynamic processes, which is traditionally neglected or highly simplified in coastal scale applications. With the increasing global focus on nature-based coastal protection, there is a need to increase our in-d...

Mine pit lakes are a common feature of open cut mine closures that extend below the local groundwater levels. Due to the relatively steep lake bottom profiles compared to natural lakes, shoreline stability remains a significant limitation for the long-term sustainability of many pit lakes, potentially impacting upon highwall geotechnical stability,...

Many shorelines around the world are fronted by canopies formed by aquatic vegetation (e.g. seagrass, kelp or mangroves). To date, much progress has been made in understanding how waves propagating towards the coast are affected by these canopies, with a particular focus on wave attenuation (e.g. Dalrymple et al., 1984). As a result, many numerical...

Canopies formed by aquatic vegetation, such as mangroves, seagrass, and kelp, play a crucial role in altering the local hydrodynamics in rivers, estuaries, and coastal regions, and thereby influence a range of morphodynamic and biophysical processes. Prediction of the influence of canopies on these hydrodynamic processes requires a fundamental unde...

This chapter discusses the modeling of morphodynamical storm impacts on coasts. It gives an overview of classes of models, the physical processes that each class resolves, and the model class applicability on the different coastal environments such as sandy, gravel and coral/rock coasts, as well as coasts with hard structures and vegetation. With r...

Coastal canopies formed by aquatic vegetation (e.g. seagrass, mangroves) or corals can be found along many coastlines worldwide and often have a significant effect on the local wave dynamics. Over the past several decades, many studies have greatly increased our understanding on the physical interaction between coastal canopies and waves in the coa...

Implementation of aquatic vegetation effects into XBeach, application to sea-swell waves, infragravity waves and wave setup.

Natural coastal dune systems provide protection against flooding from the ocean for many coastal communities around the world. An in-depth knowledge of their erosion mechanisms under oceanic stress can help to identify potential weak spots along the coastline and eventually prevent damage to the hinterland. The objective of this study was to assess...

Very-low frequency (VLF, 0.001-0.005 Hz) waves are important drivers of flooding of low-lying coral reef-islands. In particular, VLF wave resonance is known to drive large wave runup and subsequent overwash. Using a five-month dataset of water levels and waves collected along a cross-reef transect on Roi-Namur Island in the Republic of the Marshall...

Aquatic vegetation in the coastal zone attenuates wave energy and reduces the risk of coastal hazards, e.g. flooding. Besides the attenuation of sea-swell waves, vegetation may also affect infragravity-band (IG) waves and wave setup. To date, knowledge on the effect of vegetation on IG waves and wave setup is lacking, while they are potentially imp...

Abstract : Dune breaching can play a significant role in flooding events, as illustrated for instance by the Xynthia event which hit the French Atlantic coast in February 2010. The presentation will focus on the breaches which occurred on the dune of Les Boucholeurs site (South of La Rochelle, France) during Xynthia. To investigate the morphologica...

This work presents an analysis of hydrodynamics and morphological evolution during one year at Poetto Beach (South Sardinia, Gulf of Cagliari - Italy). The results, in the form of a numerical model, Delft3D, were validated using data obtained from a very reproducible low-cost video monitoring system. Subsequently, the model was used to study local...

This work presents an analysis of the hydrodynamics and morphological evolution during one year on Poetto beach (South Sardinia, Gulf of Cagliari - Italy). The results of two numerical models, Delft3D and XBeach, were validated using data obtained from coastal video monitoring. Subsequently, the models were used to study the local hydrodynamics (De...

The tidal flats in the Eastern Scheldt tidal basin (The Netherlands) are eroding as a result of the construction of the storm surge barrier. These intertidal areas are important foraging grounds for birds and therefore it is important to mitigate the negative effects of erosion. As a pilot, a small part (20 ha) of the Galgeplaat tidal flat in the m...

A numerical model, XBeach, calibrated and validated on field data collected at Roi-Namur Island on Kwajalein Atoll in the Republic of Marshall Islands, was used to examine the effects of different coral reef characteristics on potential coastal hazards caused by wave-driven flooding and how these effects may be altered by projected climate change....

In this paper, the morphological development of different nourishment designs is investigated by means of physical experiments and numerical modeling. In particular, experiments and model runs have been carried out for one design of beach nourishment and two different designs of shoreface nourishments, including different wave conditions. Models an...

Over the past decades the effect of vegetation (e.g. kelp, mangroves, sea grass) on nearshore coastal processes has received more and more attention. In recent years several numerical wave models have been extended to include this effect. In the current study, the numerical storm impact model XBeach is extended with formulations for damping of shor...

Recent research on the Scheldt estuary mainly focused on the Western Scheldt. There is now a renewed interest in the mouth of the estuary as the Flemish government explores the feasibility of large-scale morphological interventions in that area. This paper describes the ongoing development of a process-based numerical model (Delft3D) of the Scheldt...

XBeach is an open-source numerical model which originally was developed to simulate hydrodynamic and morphodynamic processes and impacts on sandy coasts with a domain size of kilometers and on the time scale of storms. Since then, the model has been applied to other types of coasts and purposes. This reference guide provides an overview of the mode...

For additional information, contact: Pacific Coastal and Marine Science Center U.S. Geological Survey Pacific Science Center 400 Natural Bridges Drive Santa Cruz, CA 95060 http://walrus.wr.usgs.gov/ Abstract This study provides viable estimates of historical storm-induced water levels in the coastal communities of Gambell and Savoonga situated on...

Op de eilanden Rottumerplaat, Rottumeroog en Zuiderduin wordt geen actief kustbeheer gevoerd en mag de natuur haar gang gaan. In deze quick-scan zijn de veranderingen van deze Waddeneilanden ten oosten van Schiermonnikoog in kaart gebracht, met name voor de periode 1989-2014.

De Slufter op Texel heeft een hoge landschappelijk en natuurlijke waarde. Hoewel de Slufter relatief oud is, en meer dan een eeuw bestaat, is het een dynamisch gebied dat constant verandert. Voor kustveiligheidsredenen wordt regelmatig ingegrepen in de natuurlijke dynamiek door middel van het verleggen van de Sluftermonding. Momenteel wordt overwog...

Novel observations of surface grain-size distributions are used in combination with intra-wave modeling to examine the processes responsible for the sorting of sediment grains on a relatively steep beach (slope = 1:7.5). The field observations of the mean grain size collected with a digital camera system at consecutive low and high tides for a 2 we...

A one-dimensional hydrostatic version of the XBeach model (Roelvink et al., 2009) is applied to hindcast swash morphodynamics measured during an accretive, and an erosive tide at Le Truc Vert beach (France) in early spring 2008 (Masselink et. al, 2009; Blenkinsopp et al., 2011). Swash hydrodynamics are solved by applying the nonlinear shallow water...

The swash zone is the part of the beach that reaches from the limit of wave run-up until the limit of wave run-down. It is recognized as being a dynamic area of the nearshore region, characterized by strong and unsteady flows, high turbulence levels, large sediment transport rates and morphological changes on a small timescale. Due to the complexit...