Predicting Crenulate Bay Profiles from Wave Fronts: Numerical Experiments and Empirical Formulae

Round 1

Reviewer 1 Report

The article deals with an in-depth investigation of the equilibrium profile of the crenulate-shaped bays. Specifically, the Authors propose a new function called ‘wave-front-bay-shape equation’,  aimed at considering wave characteristics in the calculation of the static equilibrium profile.

The empirical formula is firstly derived by means of numerical experiments performed in MIKE21 BW and then validated for a field case study, demonstrating that a relationship between the wave fronts and the equilibrium bay shape can be found.

The paper is well written and well structured. Both the Introduction and the Background sections report the most relevant references useful to understand the phenomenon and the gap the authors want to overcome. The methodology is clearly reported. Results are consistent with the performed analysis.

The paper is suitable for publication with minor revisions, as follows:

• 333-334: please, explain why the influence of wave height has not been considered among the waves' characteristics influencing the bay morphodynamic evolution and why 0.8 m has been used.
• Figure 16: The subfigure (a) is not strictly necessary
• Figure 17 should be more opportunely cited in the text. Fig. 17a is not cited

Author Response

The authors thank the Reviewer for his comment. Here attached our reply

Author Response File: Author Response.docx

Reviewer 2 Report

The paper considers the equilibrium shape of headland bays, taking into account three well known empirical geomorphological models and comparing them with a numerical simulation model based on Boussinesq equations. Besides providing a new and satisfying physical explanation of the otherwise meaningless classical models, the study provides a credible and reasonably simple approach based on a widely available wave model. A practical application is also shown.

There is no doubt in my opinion about the quality of the paper. I suggest however that before it is published, the Authors should carefully re-read the text and rewrite some paragraphs that seem to lack in clarity: in particular, the  geometrical and physical descriptions as well as the definitions  of the crenulate bay problems could be made more consistent and clear.

For instance:

(line 100 and elsewhere)  define “planform” (perhaps “bathymetry”? ), and (line 356) clarify the meaning of “leeward” (I am not sure the usual meaning applies “the direction the wind blows to”)

Lines 135 and 136 are also a bit confused. Are they the definition of the “downcoast point”?

(line 216 and elsewhere) is “embayed beach” another way of calling a “crenulate beach”?

(line 278 to 285) the paragraph is confused.  E.g. “the orthogonal are nearly normal to the straight section “?

(line 371 and elsewhere ) “wave fronts do not suffer diffraction”’ It is not clear to me how the Authors  can tell the difference  between diffraction and refraction in a closed domain  elliptic (at least I seem to understand it is so) model like the one described in paragraph 6. The Authors perhaps call the influence of bathymetry "refraction" and the influence of boundary configuration "diffraction", but it seems farfetched to me. If  it so they should please provide an explanation and /or a reference.

 

There are a few more remarks in the attached pdf file. I propose a minor revision before publication, with no need of a further review.

 

Just one further small consideration: the implicit assumption of the work is that the sediments move along the wave direction; the model however does not take the wave breaking into account , so that this could be explanation for the non-perfect coincidence of the wave fronts with the bathymetry. Am I wrong?

 

Comments for author File: Comments.pdf

Author Response

We thank the Reviewer for the stimulating discussion. Here attached our reply

Author Response File: Author Response.docx