Recent insights into inter-annual sandbar dynamics

Based on model hindcasts of the bar cycle at two locations along the Dutch coast, the dominant processes and mechanisms that govern the bar amplitude growth and decay during net inter-annual offshore migration, the occurrence of bar switches and the inter-site differences in the bar cycle return period (Tr) are identified. Bar growth and decay...

Infragravity waves and bore merging

The phenomenon of bore merging is investigated using two high-resolution laboratory experiments including bichromatic and irregular wave conditions. The locations at which waves start merging are identified and the hydrodynamic conditions in the vicinity of the merging points are examined. Bore merging takes place in the inner surf zone for all...

Dune growth due to aeolian sediment transport and the role of the beach and intertidal zone

The development of dunes is characterized by the alternating effects of erosion during storm events and growth during milder conditions. The quantification of dune growth due to aeolian processes has received some attention but uncertainty remains on where the dune sand, which accommodates growing dunes, originates from in the coastal profile....

Morphological Development of a Mega-Nourishment: First Observations at the Sand Engine

Large (mega-scale) nourishments have been proposed as a promising alternative for traditional beach and shoreface nourishments, especially for locations with large structural erosion and sufficient sediment to dredge. This paper examines the initial bathymetric evolution of the Sand Engine, a mega-nourishment of 17 million m3 protruding almost 1...

Input reduction for long-term morphodynamic simulations

Input reduction is imperative to long-term (> years) morphodynamic simulations to avoid excessive computation times. Here, we discuss the input-reduction framework for wave-dominated coastal settings introduced by Walstra et al. (2013). The framework comprised 4 steps, viz. (1) the selection of the duration of the original (full) time series of...

Modelling aeolian sediment accumulations on a beach

This paper aims to conceptually simulate observed spatial and temporal variability in aeolian sediment transport rates, erosion and deposition on a beach. Traditional strategies of modeling aeolian sediment transport rates do not account for supply limitations that are common on natural beaches. A recently developed 1D linear advection model is...

Individual wave height distributions in the coastal zone: Measurements and simulations and the effect of directional spreading

Characteristics of the individual wave height distribution in shallow water have been investigated using measured wave data and results of numerical simulations using the non-hydrostatic SWASH model. It is shown that the SWASH model is capable of reproducing the temporal and spatial variation of surface elevation in a wave flume and the...

Vortex tubes in the wave bottom boundary layer

The cause of sediment suspension events during flow reversal under waves in the nearshore is not well understood. Vortex tubes and horizontal pressure gradients have been suggested to be the cause of the suspension events. A medium sized wave flume experiment has been conducted to give insight in the hydrodynamics of the wave bottom boundary...

Wave boundary layer hydrodynamics during onshore bar migration

To study onshore bar migration and the accompanying intra-wave sediment transport a wave flume experiment was conducted. The wave flume had a rigid bottom with a single bar profile. The focus of the experiment was to measure the hydrodynamics in the wave bottom boundary layer. The results show that the skewness of bottom stress is not only...

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...