Measurements of Hydrodynamics, Sediment, Morphology and
Benthos on Ameland Ebb-Tidal Delta and Lower Shoreface

Prooijen, Bram C. van; Tissier, Marion; Wit, Floris de; Pearson, Stuart; Brakenhoff, Laura; Maarseveen, Marcel C. G. van; Vegt, M. van der; Mol, J.M.C.; Kok, Frank G.; Holzhauer, Harriette; Werf, Jebbe J. van der; Vermaas, Tommer; Gawehn, Matthijs; Grasmeijer, B.T.; Elias, Edwin; Tonnon, Pieter Koen; Reniers, Ad; Wang, Zheng Bing; Heijer, Kees den; Gelder-Maas, Carola van; Wilmink, Rinse; Schipper, C.A.; Looff, Harry de

doi:10.5194/essd-2020-13

Cited by 6 publications

(9 citation statements)

References 16 publications

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“…The 6-week CoastalGenesis2/SEAWAD field campaign was conducted in September and October 2017 by a consortium of universities and research institutes in order to improve the understanding of physical processes at the Ameland inlet [63,64]. The Ameland Inlet is a tidal inlet between the barrier islands Terschelling and Ameland at the north of the Netherlands.…”

Section: Coastalgenesis2/seawad Field Campaignmentioning

confidence: 99%

The Relationship between Sea-Swell Bound Wave Height and Wave Shape

Wit

Tissier

Reniers

2020

JMSE

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The nonlinear wave shape, expressed by skewness and asymmetry, can be calculated from surface elevation or pressure time series using bispectral analysis. Here, it is shown that the same analysis technique can be used to calculate the bound superharmonic wave height. Using measured near-bed pressures from three different field experiments, it is demonstrated that there is a clear relationship between this bound wave height and the nonlinear wave shape, independent of the measurement time and location. This implies that knowledge on the spatially varying bound wave height can be used to improve wave shape-induced sediment transport predictions. Given the frequency-directional sea-swell wave spectrum, the bound wave height can be predicted using second order wave theory. This paper shows that in relatively deep water, where conditions are not too nonlinear, this theory can accurately predict the bispectrally estimated bound superharmonic wave height. However, in relatively shallow water, the mismatch between observed and predicted bound wave height increases significantly due to wave breaking, strong currents, and increased wave nonlinearity. These processes are often included in phase-averaged wind-wave models that predict the evolution of the frequency-directional spectrum over variable bathymetry through source terms in a wave action balance, including the transfer of energy to bound super harmonics. The possibility to calculate and compare with the observed bound super harmonic wave height opens the door to improved model predictions of the bound wave height, nonlinear wave shape and associated sediment transport in large-scale morphodynamic models at low additional computational cost.

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Section: Coastalgenesis2/seawad Field Campaignmentioning

confidence: 99%

The Relationship between Sea-Swell Bound Wave Height and Wave Shape

Wit

Tissier

Reniers

2020

JMSE

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“…In this sediment-rich system, the inlets all comprise relatively large ebb-tidal delta shoals and narrow and deep inlet channels that are connected to extensive systems of branching channels, tidal flats and salt marshes in the back-barrier basins. Tidal divides (indicated by dotted lines) are formed where the tidal waves travelling through two adjacent inlets meet ( Figure 2) and are often considered to form the morphological boundaries of the tidal basins, although model studies (e.g., [1]) and field measurements [2,3] illustrate that net flow is present between the individual basins and may be larger than commonly assumed. The tidal divides are located somewhat eastward of the center of the barrier islands due to the eastward increase of tidal amplitude [4] and the prevailing westerly wind [5].…”

Section: Study Areamentioning

confidence: 99%

Future Response of the Wadden Sea Tidal Basins to Relative Sea-Level rise—An Aggregated Modelling Approach

Lodder

Wang

Elias

et al. 2019

Water

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Climate change, and especially the associated acceleration of sea-level rise, forms a serious threat to the Wadden Sea. The Wadden Sea contains the world’s largest coherent intertidal flat area and it is known that these flats can drown when the rate of sea-level rise exceeds a critical limit. As a result, the intertidal flats would then be permanently inundated, seriously affecting the ecological functioning of the system. The determination of this critical limit and the modelling of the transient process of how a tidal basin responds to accelerated sea-level rise is of critical importance. In this contribution we revisit the modelling of the response of the Wadden Sea tidal basins to sea-level rise using a basin scale morphological model (aggregated scale morphological interaction between tidal basin and adjacent coast, ASMITA). Analysis using this aggregated scale model shows that the critical rate of sea-level rise is not merely influenced by the morphological equilibrium and the morphological time scale, but also depends on the grain size distribution of sediment in the tidal inlet system. As sea-level rises, there is a lag in the morphological response, which means that the basin will be deeper than the systems morphological equilibrium. However, so long as the rate of sea-level rise is constant and below a critical limit, this offset becomes constant and a dynamic equilibrium is established. This equilibrium deviation as well as the time needed to achieve the dynamic equilibrium increase non-linearly with increasing rates of sea-level rise. As a result, the response of a tidal basin to relatively fast sea-level rise is similar, no matter if the sea-level rise rate is just below, equal or above the critical limit. A tidal basin will experience a long process of ‘drowning’ when sea-level rise rate exceeds about 80% of the critical limit. The insights from the present study can be used to improve morphodynamic modelling of tidal basin response to accelerating sea-level rise and are useful for sustainable management of tidal inlet systems.

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“…To obtain the system knowledge necessary to plan future sand nourishments in ebb-tidal deltas, a large field campaign was conducted in September 2017 at the Ameland Inlet, the CoastalGenesis2/SEAWAD field campaign [27]. The Ameland Inlet is located in the north of The Netherlands, between barrier Islands Ameland and Terschelling.…”

Section: Field Campaignmentioning

confidence: 99%

“…Furthermore, grab samples, box cores, and water samples were obtained to characterize the sediment composition in the bed and water column. For a detailed description of the field campaign, see van Prooijen et al [27].…”

Section: Field Campaignmentioning

confidence: 99%

“…In this paper, we compare near-bed velocity skewness and asymmetry from a new dataset of measurements at an ebb-tidal delta to existing parameterizations. Data were obtained during the CoastalGenesis2/SEAWAD field campaign in September 2017 at the Ameland Inlet, The Netherlands [27]. In Section 2, the field campaign and data-processing techniques are discussed.…”

Section: Introductionmentioning

confidence: 99%

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Characterizing Wave Shape Evolution on an Ebb-Tidal Shoal

Wit

Tissier

Reniers

2019

JMSE

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Field measurements of waves and currents were obtained at ten locations on an ebb-tidal shoal seaward of Ameland Inlet for a six-week period. These measurements were used to investigate the evolution of the near-bed velocity skewness and asymmetry, as these are important drivers for wave-induced sediment tranport. Wave shape parameters were compared to traditionally used parameterizations to quantify their performance in a dynamic area with waves and tidal currents coming in from different directions over a highly variable bathymetry. Spatially and temporally averaged, these parameterizations compared very well to observed wave shape. However, significant scatter was observed. The largest deviations from the parameterization were observed at the shallowest locations, where the contribution of wave-induced sediment transport was expected to be the largest. This paper shows that this scatter was caused by differences in wave-breaking, nonlinear energy transfer rate, and spatial gradients in tidal currents. Therefore, it is proposed to include the prior evolution of the wave before reaching a location in future parameterizations in numerical modeling instead of only using local parameters to predict wave shape.

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Measurements of Hydrodynamics, Sediment, Morphology and Benthos on Ameland Ebb-Tidal Delta and Lower Shoreface

Cited by 6 publications

References 16 publications

The Relationship between Sea-Swell Bound Wave Height and Wave Shape

The Relationship between Sea-Swell Bound Wave Height and Wave Shape

Future Response of the Wadden Sea Tidal Basins to Relative Sea-Level rise—An Aggregated Modelling Approach

Characterizing Wave Shape Evolution on an Ebb-Tidal Shoal

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