Effect of Variations in Water Level and Wave Steepness on the Robustness of Wave Overtopping Estimation
Round 1
Reviewer 1 Report
The paper touches an interesting topic such as the effect of mean water level and wave steepness variations on wave overtopping. However, in its present form it does not convey clearly the conclusions derived from the experimental modelling. Moreover, there is a need to analyze more in depth the physics behind the obtained results so that these results can be more directly extrapolated to other cases or situations. For this I would recommend Major Revision, considering in more depth the following points:
The possibility of characterizing the effect of waves not only in term of steepness but also in terms of non-linearity. Relating the structural exposure time frame (line 40) to the storm duration. Analyzing how the maximum wave height and surge peak water level are related for other storms (lines 70 to 72). Checking and analyzing in more depth the effect of dynamic absorption and in particular its efficiency on the obtained experimental results (from line 100 onwards). Discussing the three scenarios (figure 2) to consider dynamical changes for still water level. Intuitively I would expect that the integral of the area below that curve in figure 2 would control to an important point the obtained results. In other words, incorporate still water level and its duration together in the analysis. Consider the possibility of introducing other periods rather than Tm-1,0 (lines 145 and onwards) for the analysis (for instance T 1/3 or similar). If the length of the subsection time-series is kept constant (lines 185 and follows) the number of waves, depending on the period, will vary. Discuss also the implications of the alternative hypothesis. The obtained conclusions are not directly applicable as the authors point out (line 313 and following) for shallow water environments, and yet this is the case where many breakwaters may have to be analyzed. Discuss the implications and how to generalize the approach. When discussing the effect of increasing wave steepness (line 334 and following) no mention is made of the point of wave breaking. In other words, discuss the effect of breaking location with respect to the position of the breakwater toe and/or crest. When discussing the effect of increased reflection (line 380 and following) for more gentle steepnesses, quantify the reflection coefficient to prove the point. Regarding the discussion and conclusion section, I would recommend splitting it in two a) Discussion and b) Conclusions. Many of the paragraphs in this section now refer to future work and they would fit in better within a discussion section. More specifically within this section the effect of mean sea level and wave steepness, including the number of waves acting on a break water section and how they could affect stability and produce some deformation of the section. This would in turn affect overtopping. This is an important point and the paper would benefit from including some remarks on it and whether or not it was observed in the experiments. When mentioning the effect of increasing sea level with increases in periods and amplitudes (lines 423 and following) the authors point out the reduced influence of depth limitation. Here some more quantitative statements, directly derived from numerical simulations would benefit the analysis. Finally, when discussing that the present findings are physically plausible (lines 436 and following) some more discussion about the scaling and how that can distort the obtained results, particularly for wave overtopping with a significant content of water bubbles should be included.Author Response
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Reviewer 2 Report
The subject is worth of research and it is of straightforward application in Marine Engineering. The work is worth of publication in the Journal. This reviewer knows by far all the work and effort involved in an experimental research. However, in opinion of this reviewer some important issues should be fixed before the publication goes into its final stage.
The manuscript requires an extensive editing regarding long sentences and general structure. While this is not the objective of the review process, it makes difficult to get deep inside the real contents and ideas of the paper. Please use short sentences throughout the document, so enhancing a dynamic reading pace. There remain warnings in the bulk document regarding missing references "Fehler! Verweisquelle konnte nicht gefunden xxx werden". Please check. The Introduction section should be reconsidered. While in provides few references to the State of the Art by other authors (in fact that should not be essentially a problem), its contents unfold in the way of a theoretical background or formulation of the problem, rather than an introduction itself. Please reconsider the structure of the Introduction in a way that it could help the reader to learn about what has been already studied, what are the potential gaps in the previous researches and what the authors are coming up with in this paper. Avoid including formulae, rationales, discussion on results and so on in an Introduction section. The Intro should set the scenario for the research: what has been done, what is the present status, what are the limitations, what is the innovation, what is the objective. In the previos sense, and due to both the structure of the Introduction and of the general writing pace, it might result a bit hard to find a clear definition of the objectives of the work. This reviewer encourages the authors de include an "objective" paragraph at the end of the Introduction section (along with the reconsideration following the previous point). In that sense, the first paragraph in the Results and Discussion section provides with some sort of "objectives definition" that, in fact, should have been stated early in the document. For similar reasons, the Results and Discussion section should be reconsidered and focused exclusively on what it should be: a discussion on the highlights of the results and their importance. One final question. Leaving aside this reviewer is not questioning the contents of the research and all the involved work, what is the real innovation in the paper and how the results might affect the design of maritime structures?Author Response
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Reviewer 3 Report
The paper discusses on the effect of variations in water level and wave steepness on wave overtopping ratio at coastal dikes. In the classical experiments, the water level and wave steepness are constant during the test duration. However the water level becomes variable and wave steepness changeable during one storm. Such a variation should be included in the model experiments. The paper gives a proper experimental flow to a such demands and representative results. The publication of this manuscript as a journal paper is quite useful to engineers and researchers concerning about wave overtopping in coasts.
The following minor revision is preferable;
Time series in Fig.4 are coming from the observation data? If so, please indicate the corresponding storm name. In Fig.5. c), the spectrum has some peaks with similar heights in long period wave region. Why is the tendency in the figure different from the other cases? As a conclusion, EurOtop is available in the variable water level cases? The EurOtop is applicable in the cases with different wave steepness?Author Response
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Round 2
Reviewer 2 Report
The Authors have addresses all the suggestions of this reviewer. The paper has been definitely improved. However, the structure of the first part of the paper should be reconsidered in order to make it suitable for publication:
What it is called now Theoretical Background is still inside the Introduction section and contains, at least during its first three paragraphs, a real State fo the Art of the problem under study rather than a theoretical background itself. The formulation in it (i. e. expression (1)) should be placed, again, outside an introduction as a general rule. Please differentiate what is State of the Art and alike content (that should go to the Introduction) from what is the real Theoretical Background, say, all the theory supporting the experimental study and/or discussion and/or conclusions. And if it is not exactly a full theoretical background but a set of previous experiences instead, simply call it Background. But in any case, do not mix it with the Introduction. Avoid subsections inside the Introduction, or at least include only as a subsection inside the Introduction section the Objectives of the paper. Following the previous comments, the Objective now is stated around line 41, but, as a consequence of the above, it remains somewhat hidden and disconnected from a solid State of the Art that, in turn, should have been placed before. The following statement (starting at line 155) should be clearly explained by the Authors, even considering to include a brief annex of wave flume calibration and characteristics (otherwise any reader might question the results): A special set of hydraulic model tests is designed and conducted in a mid-sized laboratory facility. The facility has state-of-the-art wave generation and absorption qualities in order to refer to the initial question whether dynamically altered water level changes and a varying wave steepness are robustly represented in existing design formulae originating from static configurations in experimental facilities (sic).
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Round 3
Reviewer 2 Report
Accept in present form
