|The authors made some efforts to improve their manuscript, but also only partly responded or even ignored some of my previous comments. I will therefore reformulate the problems that would need to be addressed before the paper can be definitely accepted:|
-The representation of short waves in the model is still not clearly explained in section 2.1. According to the elements provided by the authors, it seems that the only effects that is represented is the enhanced bed shear stress due to orbital wave motions. If this is the case, this should be clearly stated around L.21-28. Then, does Tau_cw of eq. (5) stands for “currents & waves”? How is it computed? Does it apply to the circulation model and the sediment transport model or only the second one?
-Tidal boundary conditions. Unlike along the coastlines of the Netherlands, most coastal zones around the world are exposed to tides propagating mainly shore-normal. Why applying an alongshore phase lag to M2 and not a cross-shore one? Why not prescribing tides along the Western boundary?
-The section 4.3 of the discussion totally misses the effects of short waves. As explained in my previous review, an oceanic basin large-enough to have meso-tidal ranges has usually substantial short waves as well. As explained in nowadays numerous published studies (e.g. Bertin et al., 2009; Nahon et al., 2012; Wargula et al., 2014; etc…), short waves drive a range of processes that promote flood-dominance and tend to counteract the ebb dominance that estuaries and inlets develop due to tidal asymmetry. In the absence of short waves, this is not surprising that the authors model predicts continuous enlargement of the estuary mouth, at least without mud. Although the studies listed above rather concern tidal inlets and small estuaries, the processes explained are generic and apply to large estuaries and therefore should be included in the discussion.
Other along the text minor comments
-P5, L5: why “Dyfi, i.e. Dovey”? Then estuary should start with a capital letter.
-P5, L6: “…boundary conditions to address the main question:…”
-P6, L11: “caused mainly”
-P7, L31: erosion rather than degradation?
-P8, L4-8: -P8, L4-15: according to my understanding of Delft3D, bed level changes originate from the horizontal divergence of bedload transport as computed through the Exner equation and erosion/deposition computed as the bottom boundary condition in the suspension transport model. Does the morfac apply to both? Please clarify.
-P8, L26: “differ by two orders…”
-P10, L16-17: if waves impact the bed shear stress in the circulation model, then the current velocities will be impacted and sand fluxes computed by the EH formula as well. Please better state that the EH formula does not represent sediment stirring by short waves.
-P11, L5-6: as already commented in my previous review, why not using a parallel version of Delft3D, parallel computing is nowadays totally democratized.
-P15, L4: you may think that I’m playing with words but, if the elevation and the velocity signals are out of phase by pi/2, this is well a phase lag. I keep thinking that you mean that this phase lag is constant along the estuary.
-P15, L27: coma after notably as elsewhere in the manuscript starts by an adverb.
-P16, caption figure 4: how do you compute the tidal discharge, you remove the freshwater discharged prescribed at the river boundary?
-P20, L3: “irrelevant” is too strong, I would suggest “of limited impact”.
-P24, L26: I would rather say “the effects of short waves on the hydro-sedimentary dynamics of the estuary is limited to the stirring of sediments”.
-P25, L10: coma after “with this in mind”.
Bertin X., Fortunato, A.B. and Oliveira A., 2009. A modeling-based analysis of processes driving wave-dominated inlets. Continental Shelf Research 29, 819-834.
Nahon, A., Bertin, X., Fortunato, A.B. and Oliveira, A., 2012. Process-based 2DH morphodynamic modeling of tidal inlets: a comparison with empirical classifications and theories. Marine Geology 291–294, 1-11.
-Wargula, A., Raubenheimer, B., Elgar, S., 2014. Wave-driven along-channel subtidal flows in a well-mixed ocean inlet. Journal of Geophysical Research: Oceans, 119 (5), pp. 2987-3001.