General

The paper is well written and is almost ready for publication.

Nevertheless the authors conclude that even this intensive measurement campaign is to short and the resolution is too low to fully understand the complex flow patterns and sediment transport, still the dataset is valuable for publication.

There are a few general remarks I would advise to elaborate or to comment on in more details to improve the manuscripts:

• In the introduction the authors state appropriately that one of the main forcings for the sediment transport at intertidal flats is the (ship induced) wave exposure. Wave exposure was not measured or modelled for the field side. Nevertheless, during the six month measurement campaign a 3 week period of stormy condition occurred. The field side is close to the estuary mouth area and the main shipping lane towards the seaports of the Scheldt Estuary. Therefore, the authors should elaborate a bit more on the expected wave impacts at the field side and their consideration for not measuring, or modelling wave exposure at the field side.
• A very simple sediment transport approximation is used (alpha x u^3). To my opinion, this could be extended to some extra transport formula like Engelund-Hansen or Van Rijn formula which are commonly used in numerical models. Rather than comparing bed load to depth averaged transport in de simplified approach, which is in my opinion incorrect (see comments below), I would advise to compare the different models for total load. Transport calculations are only based on velocity measurements. A sediment concentration measurement (maybe for a short time and limited number of locations) would have be an added value to validate the approach. The authors can comment on that in the conclusions.
• The authors highlight and show the importance of wind on the sediment transport by comparing a period with strong wind conditions to a calm period. However, from the manuscript it is not clear which is the most important driving mechanism: is it the local wind shear stress causing extra wind induced currents in the channel and shallow intertidal area, or is it a more global effect of SW to NW winds and atmospheric pressure fields associated with these that cause extra surge during rough and stormy conditions leading to higher high waters and/or tidal range and thus longer submerging time of the tidal flats? From a modelling perspective, it would be very valuable to go more in depth on this, merely since the authors highlight the sensitivity of 2DH models to external forcings.

Minor remarks on the text:

Line 26: For sediment transport patters not only direction of the tidal flow and wave exposure are important, also strength of the tidal flow, tidal range, grain sizes and sand-silt ratio.

Line 56: For many estuaries 3D models are developed as well. When only investigating currents and sediment transport, computational cost is not that much an issue anymore. Unless for long term morphological simulations. However, often these 3D model tend to perform poorly in very shallow areas like on tidal flats. Another technical issue is wetting and drying which still remains a technical challenge from a numerical point of view.

Line 87: The Western part of the Scheldt Estuary is very dynamic, specially the Schaar van Spijkerplaat. How stable is the channel where the measurement (points 1) took place?

Line 99: How is rapid bed elevation increasing the percentage of silt in the bed?

Line 139: what was the threshold

Line 152: in the equation: ms^-1 is the unit, place between brackets.

Line 167: During the stormy periods, what wave heights are estimated at the measurement site? Was it measured, a wave model could give some insights?

Line 172: Why are the peak ebb and flood currents averaged over the full measurement period? Peak currents can be significantly different between neap and springtide.

Line 183: Ebb currents at 31 and 41 differ indeed from what one would expect like in 11 and 21. Is there an explanation for? The gully looks like a floodgully.

Line 225: Since the transport is only calculated based on the measured currents without taking the concentrations into account, this conclusion is in my opinion presumptuous. Generally the formulation u³ holds only for the total load with u the depth averaged velocity. I don’t think it makes sense to differentiate between total load and bed load.

Line 320-325: Needs some more clarification and motivation on why and how DS2 is compared to the linear regression of DS1. At least for some of the station: make a scatterplot with the linear regression and DS2 peak velocities. From the text it is not clear how the wind is influencing the peak velocities: is it a direct effect of the wind shear stress. Or is it due to the fact that SW tot NW winds cause a higher surge which lead to higher tidal amplitude?

Line 350: see comment before on line 225

Line 354: I don’t follow this reasoning: Why should a 2DH model overestimating the bed load transport when wind and local morphology are with sufficiently care taken into account in the model?  Therefore also the question before: is the wind playing a direct role, or is it the tide affected by the wind at the north sea? This makes a difference in how carefully local windspeed should be incorporated into the 2DH or 3D model.

Line 365: Sediment disposal is well documented for Western Scheldt.

Fig. 1a: please comment on how the arrows are calculated or refer to the source

Fig. 4: suggestion to ad a tidal curve of the waterlevels in the channel as well.

Fig. 7: caption in the figure is hard to read.