Luminescence dating methods are widely used to date coastal sediments, while luminescence tracing methods are a novel application to reconstruct coastal sediment pathways. Both methods rely on subaqueous resetting (bleaching) of luminescence signals by light. Differences in bleaching between grains and/or luminescence signals encode information on the light exposure history of individual grains and therefore yield information on past sediment transport. Here we assess the potential of multi-signal single-grain feldspar luminescence to inform about sediment pathways at Ameland tidal inlet in the Dutch Wadden Sea. We also tested whether nourished and native sands can be distinguished based on their luminescence signals.Single-grain infrared stimulated luminescence (IRSL50) and post-IR IRSL (pIRIR) were measured from samples collected from modern sea-floor deposits across the inlet. Equivalent dose (D_e) distributions were assessed using the Central Age Model (CAM), and bootstrapped versions of the Minimum Age Model (bMAM) and Maximum Age Model (bMAX) were applied to the IRSL50 D_e distributions. Spatial trends in CAM and bMAX-De reveal highest inherited doses at the tip of Ameland in the Borndiep channel, decreasing along transport pathways around the ebb-tidal delta. These patterns indicate erosion of Pleistocene sediments in the Borndiep channel and progressive bleaching of luminescence signals upon transport. Low D_e values in shallow areas reflect repeated reworking of Holocene sands within the active layer. Nourished and native sediments show indistinguishable luminescence characteristics for our dataset due to their shared Holocene origin.

Two field measurement campaigns were carried out in the Dutch Wadden Sea in winter 2023–24 and in early spring 2025. The campaigns were designed to understand and quantify sediment transport and exchange between morphological units at two spatial scales: on larger scale between two adjacent tidal basins and on smaller scale between individual channels and shoals. These observations support ongoing research to better understand sediment dynamics in the Wadden Sea, and thereby to improve sediment management strategies essential for maintaining coastal functions in the Dutch coastal system over short (days–months) to long (decades) timescales.

The resulting dataset contains point measurements at five locations in the first campaign and eight locations in the second campaign, including (1) near-bed flow velocities and velocity profiles, (2) wave characteristics, (3) suspended sediment concentrations and transport rates, and (4) local bed level dynamics, as well as data on the sediment composition of (intertidal) seabed samples. Measurements were collected simultaneously for a period of six to eight weeks in both campaigns, although some instruments collected data for only four weeks in the Winter 2023–24 campaign.

This article documents the field observations and data processing, and highlights potential applications. This dataset may contribute to a better understanding of sediment dynamics in the Dutch Wadden Sea, but also advance our understanding of channel-shoal sediment exchange mechanisms in general. It provides the field data for investigating fundamental processes controlling sediment dynamics in tidal systems, such as tide- and wind-driven flows and transport, shallow water wave dynamics, wave and current-induced resuspension, and sediment bed stability.

The data are publicly available in three versions (raw, filtered and tailored datasets) at 4TU Centre for Research Data at https://doi.org/10.4121/bbb85feb-15f9-476f-9598-b6509392117d (van Weerdenburg et al., 2026).

Employing Lagrangian particle tracking models for the study of coastal sediment transport dynamics is highly beneficial as they record the complete history of sediment transport pathways. Correctly simulating bed-particle interactions and its stochastic nature in Lagrangian models is essential to accurately estimate the direction and timescale of sediment transport. In this study we compare and assess the performance of two stochastic approaches for simulating particle erosion and deposition in Lagrangian sediment tracking models: 1) formulations proposed by Soulsby et al. (2011) that calculate probability of particles erosion and deposition from empirically-derived parameters and 2) newly-developed formulations that calculate probability of particles erosion and deposition from physical parameters. The two approaches are evaluated in the Lagrangian sediment tracking model SedTRAILS using a simulation of the dispersal of a pilot ebb-tidal delta nourishment in Ameland Inlet (Wadden Sea, Netherlands) as a case study. Our results show that the new physics-based approach represents the diffusive behavior of the nourished sediment better than the empirical approach. However, the new approach could not be fully validated yet, and the implementation of a slope term for bedload transport in the SedTRAILS transport formulations is necessary to further evaluate the new physics-based approach.

Coastal sediment budgets are a foundational source of information for coastal management decision-making. To quantify these budgets, coastal systems are often divided into “cells” based on jurisdictional boundaries or topography. However, such divisions do not account for the pathways that water and sediment particles actually take. In this study we quantify cell boundaries that emerge from numerical simulations of sand and water pathways in a barrier island-lagoon system in the Netherlands (the Western Wadden Sea). By quantifying Lagrangian particle pathways as a network, we can derive internally well-connected but externally disconnected modules. Here we show that large (O(10 km)) coherent modules develop from flow patterns at tidal timescales (12.5 h), and are persistent through varying tide and weather conditions. Conversely, modules derived from 100 µm sand pathways are less coherent and highly spatially fragmented. The difference in patterns likely relates to the longer timescales associated with sediment transport. These emergent patterns could be used to better inform coastal and estuarine management by providing physics-based sediment cell boundaries.

The Norwegian Trench (NT) is the main pathway for North Sea water into the Atlantic Ocean and for Atlantic Water (AW) into the North Sea. The processes that determine the cross-shelf exchange through the NT are key to understanding the variability of the salt budgets in the North Sea. Here, high-resolution numerical simulations from Copernicus Marine Services (CMEMS) for two recent years (2022, 2023) reveal new sources of variability of the flows in the NT. We find that wind regulates the flows in the NT, particularly in enabling the outflow of the fresh-water river plume, the Norwegian Coastal Current (NCC), in the Skagerrak during easterly wind conditions. Strong NCC outflows are associated with transport in a northward direction into the Atlantic Ocean. Furthermore, intensified eddy activity at the surface is found during strong NCC flows, causing high velocity surface currents sometimes exceeding magnitudes of 1 m/s. AW inflows partly compensate the northward outflows, keeping the net transport of 2–3 Sv constant over both years. However, the magnitudes of the AW inflows are small compared to the NCC. AW inflows that are comparable to the NCC outflows only occur during northerly winds in winter. We show that the variability of surface flows in the NT is wind induced, but that the effects of the canyon-like shape of the NT and seasonality of winds and river discharges introduce more variable deep flows than previously considered.

The seabed rarely consists solely of bare sand: often other materials, such as shells are present. They can influence sand transport by armoring the bed and modifying its roughness. Biogenic shells come in different shapes and sizes, depending on the mollusc species that produce them. To understand how changes in bivalve species composition affect sediment transport, we need a mechanistic understanding of how shell content and shell shape influence the near-bed flow and sand transport. We performed experiments in a racetrack flume, testing the effect of elongated (Ensis leei) versus rounded (Spisula subtruncata) shells on unidirectional current-driven sand transport. For both types of shells, a higher depth-averaged flow velocity was needed for initiation of motion and a decrease in bedload transport of sand was found. At a shell content of 20%, the threshold of motion of sand increased up to 75%, and bedload transport was reduced by up to 50%. These effects are explained by a balance between roughness-induced turbulence and bed armoring. Compared to a bare bed, shells decreased bed roughness by reducing ripple formation; rounded shells lowered roughness more than elongated shells, which formed roughness elements themselves, but also covered a larger fraction of the bed. However, there was no clear difference between round versus elongated shells on the overall sand transport; only shell content was key for the overall effect. Our results imply that sediment transport is likely overpredicted when a high number of shells is present in the seabed.

Decomposing turbulence from waves remains challenging due to frequency overlap and wave-turbulence interactions. Existing decomposition methods, e.g., moving average, energy spectrum analysis, and synchrosqueezed wavelet transform (SWT), produce inconsistent turbulence estimates. Here, we introduce a rotating-coordinate-based method (RoCoM), founded on two assumptions: (1) the energy spectrum in the cross-wave direction remains unaffected by wave orbital velocities, and (2) wave-wise and vertical turbulence spectra are linearly proportional to the cross-wave spectrum, with proportional constants derived from frequencies higher than the wave-dominated frequency range. Both assumptions were validated with observational data collected from the Changjiang Estuary. Comparative analyses using both in-situ observations and controlled laboratory experiments show RoCoM avoids the energy trough problem inherent in the moving average and SWT methods, yielding the most accurate power spectra and turbulent kinetic energy (TKE) estimates. In-situ data reveal that the relative errors of RoCoM are approximately 16 % for total TKE and about 6 % for TKE within the wave-dominated frequency range. Laboratory experiments further confirm its superior accuracy, demonstrating relative errors of approximately 14 % for total TKE and about 7 % for wave-band TKE. RoCoM holds significant implications for marine material transport and coastal energy development by providing robust and precise turbulence and wave energy estimates. Nonetheless, its application is currently best suited for scenarios with predominant wave propagation from a single direction, while SWT remains advantageous in environments characterized by broader directional wave spreading.

Channel deepening and narrowing are common anthropogenic modifications in estuaries, but their combined effects on estuarine circulation, stratification, and sediment transport remain insufficiently understood. This study investigates these combined impacts in the North Passage of the Changjiang Estuary, where large-scale deepening and narrowing have significantly altered hydrodynamic and sediment processes. Our analysis demonstrates that channel deepening intensifies estuarine circulation by strengthening the landward near-bed flow, thereby enhancing sediment import. Contrary to initial expectations that narrowing would promote sediment flushing, our results indicate that narrowing increases stratification, steepens along-estuary salinity gradients, and suppresses vertical mixing. Intensified stratification further reinforces estuarine circulation, promoting sediment trapping at the saltwater intrusion limit. Additionally, enhanced tidal pumping driven by increased velocity and suspended sediment concentration gradients extends the estuarine turbidity maximum both upstream and downstream, a process often overlooked in engineered estuaries. These findings challenge conventional assumptions regarding the sedimentary impacts of narrowing, emphasizing instead its critical role in amplifying estuarine circulation and sediment trapping. Our results provide new insights into sediment dynamics in river-dominated estuaries, with significant implications for estuarine management, dredging operations, water quality control, and long-term morphological stability.

The survival of salt marshes, especially facing future sea-level rise, requires sediment supply. Sediment can be supplied to salt marshes via two routes: through marsh creeks and over marsh edges. However, the conditions of tides and waves that facilitate sediment import through these two routes remain unclear. To understand when and how sediment is imported into salt marshes, 2-month measurements were conducted to monitor tides, waves, and suspended sediment concentration (SSC) in Paulina Saltmarsh, a meso-macrotidal system. The results show that the marsh creek tends to import sediment during neap tides with waves. A tidal cycle with a small tidal range result in weaker flow in the marsh creek during ebb tides, reducing the export of sediment. Waves enhance sediment supply to the marsh creek by eroding mudflats. However, strong waves can directly resuspend sediment in marsh creeks during spring tides when the water level is above the marsh canopy, enhancing sediment export through creeks. Net sediment import over marsh edges requires the opposite tidal and wave conditions: spring tides with weak waves. Spring tides provide stronger hydrodynamics, facilitating sediment import over the marsh edge. Increased SSC during the ebb phase can occur with strong waves over the marsh edge, resulting in net sediment export. Therefore, the net import or export of sediment, through the creek and over the marsh edge, depends on the combination of tidal and wave conditions. These conditions can vary between estuaries and even individual marshes. Understanding these conditions is crucial for better management of salt marshes.

Optical turbidity and acoustic sensors have been widely used in laboratory experiments and field studies to investigate suspended particulate matter concentration over the last four decades. Both methods face a serious challenge as laboratory and in-situ calibrations are usually required. Furthermore, in coastal and estuarine environments, the coexistence of mud and sand often results in multimodal particle size distributions, amplifying erroneous measurements. This paper proposes a new approach of combining a pair of optical turbidity-acoustic sensors to estimate the total concentration and sediment composition of a mud/sand mixture in an efficient way without an extensive calibration. More specifically, we first carried out a set of 54 bimodal size regime experiments to derive empirical functions of optical-acoustic signals, concentrations, and mud/sand fractions. The functionalities of these relationships were then tested and validated using more complex multimodal size regime experiments over 30 optical-acoustic pairs of 5 wavelengths (420, 532, 620, 700, 852 nm) and six frequencies (0.5, 1, 2, 4, 6, 8 MHz). In the range of our data, without prior knowledge of particle size distribution, combinations between optical wavelengths 620–700 nm and acoustic frequencies 4–6 MHz predict mud/sand fraction and total concentration with the variation <10% for the former and <15% for the later. The results also suggest that acoustic-acoustic signals could be combined to produce meaningful information regarding concentration and mud/sand fraction, while no useful knowledge could be extracted from a combination of optical-optical pairs. This approach therefore enables the robust estimation of suspended sediment concentration and composition, which is particularly practical in cases where calibration data is insufficient.

Creeks are essential for salt marshes by conveying water and sediment through this geomorphic system. In this paper, we investigate the mechanisms that determine the residual sediment flux using measurements conducted in tidal creeks in salt marshes of the Yangtze Estuary. A main creek and a secondary creek were studied to explore whether the mechanisms determining residual sediment fluxes through the main creek differ from those in the secondary creek. Measurements in creeks were carried out over 5 years, spanning different months. Sediment import was found during most tides, both in the main creek and the secondary creek, implying that creeks in Chongming generally function as a conveyor belt of sediment into the marsh. However, sediment export can occur during certain overbank tides. When comparing the role of creeks in drainage and sediment delivery, the main creek functions more in delivering sediment while the secondary creek primarily serves as a drainage conduit. To better understand the mechanisms behind sediment fluxes, the residual sediment flux was compared with the residual discharge and the sediment differential (differences in sediment concentration between flood and ebb). Overbank tides generally lead to a net outward discharge as more water from saltmarshes can be concentrated into the marsh creek during ebb tides. This net outward discharge tends to export more sediment during ebb tides. However, due to the sediment abundance during the flood phase in the turbid environment, sediment import can be expected even with the residual export of water. Export of sediment was only found for the few tides with a net outward discharge and a small positive sediment concentration differential. Large negative sediment differentials (larger averaged suspended sediment concentration during ebb tides) have not been observed because the sediment supply during ebb is limited. This paper unravels how the sediment differential and residual discharge contribute to the residual sediment flux, providing a better understanding of sediment dynamics in marsh creek systems.

The adaptive capacity of ecosystems, or their ability to function despite altered environmental conditions, is crucial for resilience to climate change. However, the role of landscape complexity or species traits on adaptive capacity remains unclear. Here, we combine field experiments and morphodynamic modelling to investigate how ecosystem complexity shapes the adaptive capacity of intertidal salt marshes. We focus on the importance of tidal channel network complexity for sediment accumulation, allowing vertical accretion to keep pace with sea-level rise. The model showed that landscape-scale ecosystem complexity, more than species traits, explained higher sediment accumulation rates, despite complexity arising from these traits. Landscape complexity, reflected in creek network morphology, also improved resilience to rising water levels. Comparing model outcomes with real-world tidal networks confirmed that flow concentration, sediment transport and deposition increase with drainage complexity. These findings emphasize that natural pattern development and persistence are crucial to preserve resilience to climate change.

Storm surge barriers and closure dams influence estuarine morphology. Minimizing consequential ecological impacts requires a thorough understanding of the morphological adaptation mechanisms and associated time scales. Both are unraveled using three decades of morphological measurements on the adaptation of the Eastern Scheldt estuary (The Netherlands) to a storm surge barrier and closure dams. Both the storm surge barrier (through a decrease in cross-sectional area) and closure dams (inducing a reduction in surface area of the estuary) contributed to a reduction in tidal prism. As a smaller tidal prism implies a smaller equilibrium volume of the channels, the channels demand sediment to adjust. Consequently, by providing sediment to the channels, the intertidal flats erode. Erosion rates decreased while the sediment demand of the channels attenuated. This attenuation in sediment demand resulted mainly from tidal prism gains, caused by intertidal flat erosion and sea level rise. Erosion rates of the intertidal flats decreased further while they flattened to adapt to the reduced tidal velocities. Furthermore, storms caused erosion events, after which the long-term adaptation pace of intertidal flats suddenly reduced. Despite decreasing erosion, sea level rise enhances the drowning of intertidal flats in sediment-scarce estuarine systems, thereby pressuring these estuarine ecosystems and raising the need for mitigation measures.

For the management of estuaries and the preservation of tidal flats it is crucial to understand the tidal flat shape and development. Previous work focused predominantly on the quasi-equilibrium shape of tidal flats along open coasts with a dominant cross-shore flow and wave exposure. This paper evaluates the shape of fringing tidal flats in engineered estuaries, where longshore velocities generally dominate. Using a long-term (20 years) topographic data set of an anthropogenically modified estuary in the Netherlands (the Western Scheldt estuary), we relate key profile shape parameters and changes over time to natural and anthropogenic processes. In an engineered estuary, the tidal flat shape depends on the estuary geometry, hydrodynamic forcings and human interventions. In contrast to open coast tidal flats, the presence of the channel and dominant longshore flow determines the available cross-shore length (accommodation space) of the tidal flat and the shape of the tidal flat. This accommodation space defines the maximum tidal flat height and opportunity for marsh development. We propose the use of the Index of Development, indicating to what extend tidal flats have space to develop. This index is not only influenced by longshore and cross-shore flow, but also (or even more) by hydraulic structures, dike realignments and channel migration. Especially the latter two strongly influence the accommodation space and thereby the maximum tidal flat height and the opportunity for marsh development. For large stretches of the Western Scheldt, the accommodation space is too small, and the majority of the tidal flats do not vertically extent to mean high water. The success of tidal flat and marsh restoration projects depends on the accommodation space.

Marsh creeks are perceived as important conduits for transporting water and sediment between mudflats and marshes. In order to advance the understanding of the transport mechanisms in creeks, the source and ultimate sink of sediment which moves between mudflats and marshes through creek channels need further investigation. Therefore, two field campaigns were conducted in two intertidal systems with varying sediment availability. The water depth, flow velocity, suspended sediment concentration, and bed level change were measured simultaneously in a marsh creek and on the adjacent mudflat in Chongming Island (China) and in Paulina Saltmarsh (the Netherlands). Paulina Saltmarsh is much smaller, more frequently flooded, and has lower sediment concentration than Chongming. These contrasting conditions allow for a comparison of transport mechanisms and functioning of the creek. Both systems first show that the high suspended sediment concentration (SSC) measured in marsh creeks is mainly the consequence of sediment advection rather than local erosion. In addition, erosion in marsh creeks is usually limited during ebb tides, reducing the export of sediment through these creeks. However, differences have been observed between two systems. The measured SSC was highly asymmetric between flood and ebb tides in Chongming. Large peaks in SSC during the flood period can be observed for most tidal cycles. The marsh creeks in Chongming therefore function as conduits for sediment import. Additionally, there are distinct overbank and underbank tides in Chongming. Sediment was trapped and retained in creeks during underbank tides, which can then be eroded and transported to the marsh during subsequent overbank tides. We also observed that mudflats in Chongming quickly recovered after erosion. These mechanisms have not been observed in Paulina Saltmarsh, where net sediment export via the marsh creek was observed due to a lack of abundant sediment in suspension during flood tides. Furthermore, the remaining bed surface of mudflats after an erosion event was stronger than before, limiting further erosion in Paulina Saltmarsh. These findings from the two systems indicate that the role of creeks in sediment import/export depends on the availability of sediment from mudflats, shedding light on nourishment strategies for salt marshes.

Intertidal ecosystems are threatened by sea level rise and anthropogenic pressures. Understanding the processes controlling the morphodynamic developments of tidal flats is crucial for sustainable management of these systems. Analysis of three extensive fieldwork campaigns carried out on two adjacent mudflats fringing the Dutch Western Wadden Sea (from 2016 to 2018) provides important new insights into the conditions controlling a permanent increase of tidal flat elevation (‘accretion’), in which the wind and consolidation processes play a pivotal role. Sediment temporarily settles (‘deposition’) on the flats during a period of high suspended sediment availability and water level setup (often following a storm). A tidal flat accretes when a new layer of sediment over-consolidates: a state in which the bed strength is much larger than it would attain during inundated conditions, due to high stresses experienced during prolonged drying. This happens when a phase of sediment deposition is followed by a sufficiently long period with a low ambient water table (phreatic level) and aerial exposure. The chronological order of sediment deposition and over-consolidation provides a window of opportunity for tidal flat accretion. Such a window of opportunity depends on the hydrodynamic forcing (tides, waves, wind), on the consolidation state of the bed, and on sediment availability. Wind plays a crucial role in creating the conditions for tidal flat accretion because the wind direction influences the duration of a low water table and aerial exposure and therefore (over-)consolidation rates, which we refer to as the ‘winds of opportunity’. An abundance of sediment may even limit tidal flat accretion, because large deposition rates substantially increase consolidation timescales.

Rising coastal flood risk and recent disasters are driving interest in the construction of gated storm surge barriers worldwide, with current studies recommending barriers for at least 11 estuaries in the United States alone. Surge barriers partially block estuary-ocean exchange with infrastructure across an estuary or its inlet and include gated areas that are closed only during flood events. They can alter the stratification and salt intrusion, change sedimentary systems, and curtail animal migration and ecosystem connectivity, with impacts growing larger with increasing gate closures. Existing barriers are being used with increasing frequency due to sea level rise. New barrier proposals typically come with maximum closure frequency recommendations, yet the future adherence to them is uncertain. Given that the broader environmental effects and coupled-human dynamics of surge barriers are not well-understood, we present an interdisciplinary research agenda for this increasingly prevalent modification to our coastal zone.

Ebb tidal deltas (ETDs) are highly dynamic features of sandy coastal systems, and coastal management concerns (e.g., nourishment and navigation) present a pressing need to better describe and quantify their evolution. Here we propose two techniques for leveraging the availability of high-resolution bathymetric surveys to generate new insights into the dynamics and preservation potential of ebb-tidal deltas. The first technique is conformal mapping to polar coordinates, using Ameland ebb-tidal delta in the Netherlands as a case study. Since the delta tends to evolve in a clockwise direction around the inlet, this approach provides an improved quantification and visualization of the morphodynamic behaviour as a timestack. We clearly illustrate the sediment bypassing process and repeated rotational migration of channels and shoals across the inlet from updrift to downdrift coasts. Secondly, we generate a decadal scale (1975–2021) stratigraphic model from the differences between successive bathymetries. This stratigraphy showcases the delta's depositional behaviour through space and time, and provides a modern analogue for prehistoric ebb-tidal deltas. During the surveyed period, inlet fills form the largest and most stable deposits, while the downdrift swash platform is the most stable structure over longer periods. Together, these approaches provide new perspectives on ebb-tidal delta dynamics and preservation potential which are readily applicable to other sites with detailed bathymetric data. These findings are valuable at annual to decadal timescales for coastal management (e.g., for planning sand nourishments) and also at much longer timescales for interpreting stratigraphy in ancient rock records.

Coastal mangroves, thriving at the interface between land and sea, provide robust flood risk reduction. Projected increases in the frequency and magnitude of climate impact drivers such as sea level rise and wind and wave climatology reinforce the need to optimize the design and functionality of coastal protection works to increase resilience. Doing so effectively requires a sound understanding of the local coastal system. However, data availability particularly at muddy coasts remains a pronounced problem. As such, this paper captures a unique dataset for the Guyana coastline and focuses on relations between vegetation (mangrove) density, wave attenuation rates and sediment characteristics. These processes were studied along a cross-shore transect with mangroves fringing the coastline of Guyana. The data are publicly available at the 4TU Centre for Research Data (4TU.ResearchData) via https://doi.org/10.4121/c.5715269 (Best et al., 2022) where the collection Advancing Resilience Measures for Vegetated Coastline (ARM4VEG), Guyana, comprises of six key datasets.

Suspended sediment concentrations typically exceeded 1 g L−1 with a maximum of 60 g L−1, implying that we measured merely fluid-mud conditions across a 1 m depth. Time series of wind waves and fluid-mud density variations, recorded simultaneously with tide elevation and suspended sediment data, indicate that wave–fluid-mud interactions in the nearshore may be largely responsible for the accumulation of fine, muddy sediment along the coast. Sediment properties reveal a consolidated underlying bed layer. Vegetation coverage densities in the Avicennia-dominated forest were determined across the vertical with maximum values over the first 20 cm from the bed due to the roots and pneumatophores.

Generalized total wave attenuation rates in the forest and along the mudflat were between 0.002–0.0032 m−1 and 0.0003–0.0004 m−1 respectively. Both the mangroves and the mudflats have a high wave-damping capacity. The wave attenuation in the mangroves is presumably dominated by energy losses due to vegetation drag, since wave attenuation due to bottom friction and viscous dissipation on the bare mudflats is significantly lower than wave dissipation inside the mangrove vegetation. Data collected corroborate the coastal defence function of mangroves by quantifying their contribution to wave attenuation and sediment trapping. The explicit linking of these properties to vegetation structure facilitates modelling studies investigating the mechanisms determining the coastal defence capacities of mangroves.

The amount of suspended fines in the southern North Sea strongly depends on their exchange with the sandy seabed. This exchange is governed by resuspension of fines during storms, followed by burial in the week thereafter. Despite its importance for fine sediment dynamics, the burial of fines into a sandy seabed is currently not well understood. This paper presents a mechanistic conceptual model, explaining how the interaction of migrating small ripples and larger megaripples can bury fine sediment in a sandy seabed shortly after storms. The burial process consists of four phases forming a dynamic cycle. A storm stirs up the bed, remobilising fines, while forming megaripples. After the storm, fines can settle again depositing atop the sandy seabed. Interaction between bedforms of different scales is then crucial to bury fines 1–2 dm within the seabed. Megaripples formed during storms gradually adjust to calmer conditions in the waning of storms. During this adjustment period, fines are buried by current-induced ripples in the troughs of the former megaripples. Field measurements collected in 2017 corroborate this conceptual model, showing fines in distinct patches, both horizontally and vertically. Furthermore, fines are found up to 10–15 cm in the seabed shortly after storms. The data further reveal how fine sediment occurrences on and within the seabed vary strongly over multiple length scales. They both vary on the mega-scale (kilometres) and on the micro-scale (metres-centimetres). As the micro-scale is multiple orders of magnitude smaller than the scale on which hydro-morphological models operate, parameterisations are required to aggregate the effect of burial in numerical models.