Modeling Multi-Fraction Coastal Aeolian Sediment Transport With Horizontal and Vertical Grain-Size Variability

Grain size affects the rates of aeolian sediment transport on beaches. Sediment in coastal environments typically consists of multiple grain-size fractions and exhibits spatiotemporal variations. Still, conceptual and numerical aeolian transport models are simplified and often only include a single fraction that is constant over the model...

Depth-Resolved Modelling of Intra-Swash Morphodynamics Induced by Solitary Waves

We present a fully coupled 2DV morphodynamic model, implemented in OpenFOAM^® that is capable of simulating swash-zone morphodynamics of sandy beaches. The hydrodynamics are described by the Reynolds-averaged Navier–Stokes (RANS) equations with a (Formula presented.) turbulence model and the Volume of Fluid (VoF) approach for...

Novel sediment sampling method provides new insights into vertical grain size variability due to marine and aeolian beach processes

In sandy beach systems, the aeolian sediment transport can be governed by the vertical structure of the sediment layers at the bed surface. Here, data collected with a newly developed sand scraper is presented to determine high-resolution vertical grain size variability and how it is affected by marine and aeolian processes. Sediment samples...

Chenier Formation Through Wave Winnowing and Tides

Cheniers are ridges consisting of coarse-grained sediments, resting on top of the fine sediment that forms the otherwise muddy coast. In this paper, we use Delft3D to explore how cheniers are formed through wave winnowing. We identify three phases of chenier development: (a) a winnowing phase, during which mud is washed out of the seabed...

Modelling cross‐shore shoreline change on multiple timescales and their interactions

In this paper, a new approach to model wave‐driven, cross‐shore shoreline change incorporating multiple timescales is introduced. As a base, we use the equilibrium shoreline prediction model ShoreFor that accounts for a single timescale only. High‐resolution shoreline data collected at three distinctly different study sites is used to train...

Observations of cross-shore chenier dynamics in Demak, Indonesia

Cheniers are important for stabilising mud-dominated coastlines. A chenier is a body of wave-reworked, coarse-grained sediment consisting of sand and shells overlying a muddy substrate. In this paper we present and analyse a week of field observations of the dynamics of a single chenier along the coast of Demak, Indonesia. Despite relatively...

Cross-shore intertidal bar behavior along the dutch coast: Laser measurements and conceptual model

Intertidal bars are naturally occurring morphological features along the waterline of sandy beaches. Present quantitative knowledge on intertidal bar behavior is limited, due to the scarcity of data resources and the limitations of traditional survey techniques. To investigate and quantify the cross-shore morphologic behavior of intertidal...

The impact of wind on flow and sediment transport over intertidal flats

Sediment transport over intertidal flats is driven by a combination of waves, tides, and wind-driven flow. In this study we aimed at identifying and quantifying the interactions between these processes. A five week long dataset consisting of flow velocities, waves, water depths, suspended sediment concentrations, and bed level changes was...

Wave Generation of Gravity-Driven Sediment Flows on a Predominantly Sandy Seabed

Wave-supported gravity flows (WSGFs) generate rates of sediment flux far exceeding other cross-shelf transport processes, contributing disproportionately to shelf morphology and net cross-shelf fluxes of sediment in many regions worldwide. However, the conditions deemed necessary for the formation of WSGF limit them to a narrow set of shelf...

A conceptual model for spatial Grain size variability on the surface of and within beaches

Grain size on the surface of natural beaches has been observed to vary spatially and temporally with morphology and wave energy. The stratigraphy of the beach at Duck, North Carolina, USA was examined using 36 vibracores (~1-1.5 m long) collected along a cross-shore beach profile. Cores show that beach sediments are finer (~0.3 mm) and more...

Modeling Swash zone sediment transport at Truc Vert beach

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...

The effect of the longshore dimension on dune erosion

The effect of the longshore dimension on dune erosion is examined numerically with a 2DH process based model XBeach. Exploratory simulations are presented to examine longshore effects due to directionally spread waves, longshore variation in topography and longshore variation in bathymetry. The simulations reveal that alongshore sediment...

On the scaling of sediment transport in the nearshore

Scale relations are necessary to choose proper sediment for physical models. The use of lightweight artificial sediment makes it possible to preserve the Reynolds number, Shields number and relative settling velocity altogether. There is also the possibility to preserve the Shields number in combination with the Dean number which would be more...

Yearly-averaged sand transport at the -20 and -8 NAP depth contours of the Jarkus profiles 14, 40, 76 and 103