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Modeling of wave attenuation by vegetation with XBeach

Van Rooijen, A.A. (author), Van Thiel de Vries, J.S.M. (author), McCall, R.T. (author), Van Dongeren, A.R. (author), Roelvink, J.A. (author), Reniers, A.J.H.M. (author)

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 was extended with formulations found in...

conference paper 2015

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Tilt current meter array: Field validation

Radermacher, M. (author), Thackeray, Z.H. (author), De Schipper, M.A. (author), Gordon, L. (author), Chrystal, C. (author), Leuci, R. (author), Reniers, A.J.H.M. (author)

Measurements of nearshore currents can be performed using a range of existing measurement techniques. Although every technique has its specific benefits, capturing strong spatial gradients in a flow field with sufficiently high spatial resolution often proves to be difficult due to high costs or practical difficulties associated with these...

conference paper 2015

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Field Observations of Surf Zone-Inner Shelf Exchange on a Rip-Channeled Beach

Brown, J.A. (author), MacMahan, J.H. (author), Reniers, A.J.H.M. (author), Thornton, E.B. (author)

Cross-shore exchange between the surf zone and the inner shelf is investigated using Lagrangian and Eulerian field measurements of rip current flows on a rip-channeled beach in Sand City, California. Surface drifters released on the inner shelf during weak wind conditions moved seaward due to rip current pulses and then returned shoreward in an...

journal article 2015

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Transport of larvae and detritus across the surf zone of a steep reflective pocket beach

Shanks, A.L. (author), MacMahan, J. (author), Morgan, S.G. (author), Reniers, A.J.H.M. (author), Jarvis, M. (author), Brown, J. (author), Fujimura, A. (author), Griesemer, C. (author)

Larvae of many intertidal species develop offshore and must cross the surf zone to complete their onshore migration to adult habitats. Depending on hydrodynamics, the surf zone may limit this migration, especially on reflective rocky shores. As a logistically tractable analog of a rocky shore environment, we carried out a comprehensive...

journal article 2015

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Field observations of tidal flow separation at a mega-scale beach nourishment

Radermacher, M. (author), Zeelenberg, W. (author), De Schipper, M. (author), Reniers, A. (author)

Large beach nourishments are often considered an efficient way to deal with coastal zone management issues, notably coastal erosion. Such large nourishments can act as a geometric perturbation, which might cause the tidal current to detach from the coastline. The Sand Motor is a mega-scale beach nourishment in the Netherlands. Field observations...

conference paper 2015

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Surfzone monitoring using rotary wing unmanned aerial vehicles

Brouwer, R.L. (author), De Schipper, M.A. (author), Rynne, P.F. (author), Graham, F.J. (author), Reniers, A.J.H.M. (author), Macmahan, J.H. (author)

This study investigates the potential of rotary wing unmanned aerial vehicles (UAVs) to monitor the surfzone. This paper shows that these UAVs are extremely flexible surveying platforms that can gather nearcontinuous moderate spatial resolution and high temporal resolution imagery from a fixed position high above a study site. The rotary wing...

journal article 2015

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Scaling laws for the upper ocean temperature dissipation rate

Bogucki, D.J. (author), Huguenard, K. (author), Haus, B.K. (author), Özgökmen, T.M. (author), Reniers, A.J.H.M. (author), Laxague, N.J.M. (author)

Our understanding of temperature dissipation rate ? within the upper ocean boundary layer, which is critical for climate forecasts, is very limited. Near-surface turbulence also affects dispersion of contaminants and biogeochemical tracers. Using high-resolution optical turbulence measurements, scaling laws for ? are investigated under forcing...

journal article 2015

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The spatial-temporal variability of air-sea momentum fluxes observed at a tidal inlet

Ortiz-Suslow, D.G. (author), Haus, B.K. (author), Williams, N.J. (author), Laxague, N.J.M. (author), Reniers, A.J.H.M. (author), Graber, H.C. (author)

Coastal waters are an aerodynamically unique environment that has been little explored from an air-sea interaction point of view. Consequently, most studies must assume that open ocean-derived parameterizations of the air-sea momentum flux are representative of the nearshore wind forcing. Observations made at the New River Inlet in North...

journal article 2015

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Scale-selective Validation of Morphodynamic Models

Bosboom, J. (author), Reniers, A.J.H.M. (author)

Although it is generally acknowledged that the practical predictability at smaller scales may be limited, output of high-resolution morphodynamic area models is mostly presented at the resolution of the computational grid. The so- presented fields typically are realistic looking, but not necessarily of similar quality at all spatial scales....

conference paper 2014

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Displacement-based error metrics for morphodynamic models

Bosboom, J. (author), Reniers, A.J.H.M. (author)

The accuracy of morphological predictions is generally measured by an overall point-wise metric, such as the mean-squared difference between pairs of predicted and observed bed levels. Unfortunately, point-wise accuracy metrics tend to favour featureless predictions over predictions whose features are (slightly) misplaced. From the perspective...

journal article 2014

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Alongshore topographic variability at a nourished beach

De Schipper, M.A. (author), De Vries, S. (author), Ranasinghe, R.W.M.R.J.B. (author), Reniers, A. (author), Stive, M.J.F. (author)

The present paper examines the generation and inter-annual evolution of alongshore variability in topography measured after the implementation of a sand nourishment. The magnitude of the topographic variability is quantified using 3.5 years of monthly survey data. The emergence and temporal change in alongshore morphological variability is...

conference paper 2013

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Displacement based error metric for morphodynamic models (abstract)

Bosboom, J. (author), Reniers, A.J.H.M. (author)

The quality of a morphological prediction is often expressed by an overall grid-point based skill score based on the Mean Squared Error (MSE) between the predicted and observed bed levels (Sutherland et al., 2004). Although the MSE is a good measure of the overall error between model and observations, it tends to penalize rather than reward the...

conference paper 2013

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Observations and modeling of steep-beach grain-size variability

Reniers, A.J.H.M. (author), Gallagher, E.L. (author), MacMahan, J.H. (author), Brown, J.A. (author), Van Rooijen, A.A. (author), Van Thiel de Vries, J.S.M. (author), Van Prooijen, B.C. (author)

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...

journal article 2013

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Morphological developments after a beach and shoreface nourishment at Vlugtenburg beach

De Schipper, M.A. (author), De Vries, S. (author), Ranasinghe, R.W.M.R.J.B. (author), Reniers, A.J.H.M. (author), Stive, M.J.F. (author)

Typically a beach is out of equilibrium after a nourishment is installed. To observe how a nourished beach behaves on the timescale of storms a monitoring campaign was set up at Vlugtenburg beach after a nourishment in the spring of 2009. Here we show a sediment budget analysis of the first 2.5 years for a coastal domain spanning 1750 m...

conference paper 2012

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Modeling Swash zone sediment transport at Truc Vert beach

Van Rooijen, A. (author), Reniers, A. (author), Van Thiel de Vries, J.S.M. (author), Blenkinsopp, C. (author), McCall, R. (author)

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...

conference paper 2012

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Vortical VLF motions under shore-normal incident waves

De Schipper, M.A. (author), Reniers, A. (author), MacMahan, J. (author), Ranasinghe, R.W.M.R.J.B. (author)

Field observations and numerical model simulations are examined to investigate the magnitude of vortical very low frequency (VLF) velocity fluctuations (i.e. large scale surfzone eddies) under different offshore wave forcing. Observations of vortical VLF motions under shore -normal wave incidence at Duck, NC, USA are re-analyzed and compared...

conference paper 2012

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Vortex tubes in the wave bottom boundary layer

Henriquez, M. (author), Reniers, A.J.H.M. (author), Ruessink, B.G. (author), Stive, M.J.F. (author)

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...

conference paper 2012

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The ECORS-Truc Vert’08 nearshore field experiment: Presentation of a three-dimensional morphologic system in a macro-tidal environment during consecutive extreme storm conditions

Senechal, N. (author), Abadie, S. (author), Gallagher, E. (author), MacMahan, J. (author), Masselink, G. (author), Michallet, H. (author), Reniers, A. (author), Ruessink, G. (author), Russell, P. (author), Sous, D. (author)

A large multi-institutional nearshore field experiment was conducted at Truc Vert, on the Atlantic coast of France in early 2008. Truc Vert’08 was designed to measure beach change on a long, sandy stretch of coast without engineering works with emphasis on large winter waves (offshore significant wave height up to 8 m), a three-dimensional...

journal article 2011

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The effect of the longshore dimension on dune erosion

Van Thiel de Vries, J.S.M. (author), Van Dongeren, A.R. (author), McCall, R. (author), Reniers, A. (author)

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...

conference paper 2011

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On the initiation of nearshore morphological rhythmicity

De Schipper, M.A. (author), Ranasinghe, R.W.M.R.J.B. (author), Reniers, A.J.H.M. (author), Stive, M.J.F. (author)

Nearshore rhythmicity is often initiated in the period just after a storm where the subtidal bar is turned alongshore uniform. The initiation time as well as the length scales of the created rhythmicity varies from one storm period to another. Here we show that the post-storm wave conditions are related to the initiation of the morphological...

conference paper 2010