Local Scour around Tandem Double Piers under an Ice Cover
Round 1
Reviewer 1 Report
The article is devoted to scouring around different configurations of double bridge piers, taking into account potential effect of an ice cover. This may rise scientific and practical interest, however the article suffers from the form of presentation. First of all, it reads badly! It is advised to shorten the article, to be more selective and comprehensive in results description. Better indicate and emphasize the relevant study outputs. The paper has now more a “technical” value, i.e. reports in detail on observations in specific testing conditions with an attempt to derive a formula for these.
Therefore a major editorial revision is recommended.
Also important, the relevance of the study is not convincing. The largest scour and the related thread to the bridge pier(s) occurs during high waters, especially during extreme floods. Typically, the run-off in winter conditions forming the an cover is lower. If flow rate during the ice cover is smaller than that during a flood, then the resulting scour depth under ice cower is smaller than that for flooding conditions. Without understanding and evaluating hydrological regimes this approach can have no importance to what is being considered.
No mention about ice jamming on the bridge piers, which may be more important for problem statement.
Specific comments:
Improve legibility of Figure 2.
Figure 2, 4 and 6 – it is not necessary to show the time dependent evolution of the scour parameters. Only the final equilibrium conditions should be provided in a graphical form or a table form along with stream parameters – suggested extension of table 1, which collects all relevant stream and scour parameters.
Fig. 8 partly illegible.
- 214-223 – hardly to follow.
- 318-321 – not clear (vs Fig.9).
There is an imbalance between the figures and text volume.
Conclusions should be conclusions!
Author Response
Dear Reviewer:
Thank you so much for your review and providing us with these insightful comments. We revised our paper by following your comments. We believe the revised paper has been improved a lot.
Please see attached discussion letter.
Sincerely yours,
Jueyi Sui
Author Response File: 
Author Response.pdf
Reviewer 2 Report
This paper studies the local scour around tandem double piers under an ice cover flow condition experimentally. The experiment is reasonably designed, the results are sufficiently explained and discussed, the paper is well organized and written. The reviewer suggests its publication after some minor improvement.
- The experimental setup is not well explained. It is not clear how is the ice cover simulated. Some pictures of the experimental setup or a three-dimensional drawing could be helpful.
- Careful proofreading is suggested. For example in Line 42: Kothyari et al; (1992).
- A dot should be presented after et al.
Comments for author File: Comments.pdf
Author Response
Dear Reviewer:
Thank you so much for your review and providing us with these insightful comments. We revised our paper by following your comments. We believe the revised paper has been improved a lot.
Please see attached discussion letter.
Sincerely yours,
Jueyi Sui
Reviewer 3 Report
The reviewer wants to thank the author for the paper presenting an experimental investigation of the scour caused by two cylindrical structures close to each other in addition to a free water surface covered with a simulated ice layer. S/he has some suggestions and questions:
*1) The citation style is not correct and yes, the reviewer knows that the journal doesn’t require this for the first submission. Anyway, et al. and not et al … the dot is important. Please consider using LaTex.
*2) Line (L) 100: The variables D50, H and L are not introduced. It’s not hard to guess but nevertheless, this is not good practice.
*3) Figure 1 / general set up: Please include a picture of the set-up so that the reader understand it better.
*4) Please describe how and with which accuracy the discharge as well as the water level was measured.
*5) The measurement of the final surface of the sand must be described in more detail. Which instrument/technique was used? Resolution as well as accuracy? Was the flume emptied or could this measurement be done under water?
*6) Table 1: the velocity v was measured or is it just the division of the discharge by the water area? Please clarify this?
*7) Where was the H measured and how (as asked previously)? Please clarify this.
*8) The text after the Table 1 should be placed in the results section and replaced with a detailed description how the final source profile was measured.
*9) Figure 3 and in general: Many figures can be placed side by side to use the full width of the page. Please reduce the empty space around the figures.
*10) Figure 3 and ongoing: please add a specific sketch in which the presented variables are introduced and also provide in the methodology section how each value was computed based on the experimental data.
*11) Figure 5: The reviewer doesn’t understand why the authors not showed the precise values on the y-axis and hence let the reader check.
*12) Figure 10 a) those results are only including the fixed H value? And b) only the constant velocity? Please clarify this and put two figures side by side.
*13) one more question considering the set-up: are the styrofoam panels linked to each other and how are they kept in place? Are they free floating or is the water depth fixed with it? Did the authors also conducted experiments without it to identify the effect for this specific set-up? Sorry, if the reviewer missed this in the paper.
The reviewer thanks the authors for their paper and is looking forward reading it again. Thank you!
Comments for author File: Comments.pdf
Author Response
Dear Reviewer:
Thank you so much for your review and providing us with these insightful comments. We revised our paper by following your comments. We believe the revised paper has been improved a lot.
Please see attached discussion letter.
Sincerely yours,
Jueyi Sui
Round 2
Reviewer 1 Report
The paper has significantly improved. It is still advised to make sure that it is cleared from oversights (like l. 261) and to improve the layout (unnecessary frames) and legibility of figures (e.g. Fig 6).
Conclusions (especially p.1) contain text that could be placed in a section before. Could you please try again to make it more consistent and conclusive rather than descriptive?
Author Response
Dear Reviewer:
Thank you so much for your review and providing us with these insightful comments. We revised our paper by following your comments. We believe the revised paper has been improved a lot. Here are our replies to your comments.
Sincerely yours,
Jueyi Sui
Your comments: The paper has significantly improved. It is still advised to make sure that it is cleared from oversights (like l. 261) and to improve the layout (unnecessary frames) and legibility of figures (e.g. Fig 6).
----Our Discussion: Thank you for your comments! Line 261 has been corrected. We tried our best to improve the legibility of figures in our paper.
Your comments: Conclusions (especially p.1) contain text that could be placed in a section before. Could you please try again to make it more consistent and conclusive rather than descriptive?
-----Our Discussion: Thank you for your comments! This has been revised.
Reviewer 3 Report
The reviewer thanks the authors for their corrections and answers. Some further/new points should be addressed:
*a) A more general comment: The reviewer is still surprised how many laboratories don’t use continuative discharge measurement. There are very simple and cheap solution to measure the water surface continuative. This ensures that especially in the case of such long flumes no additional wave occurs in the flow and the conditions are really steady.
*b) Please improve the quality of the new figure one and clearly mention how many points of the source were measured with this manual device.
*c) The information about the tests without the ice covering is missing. The reviewer asked, if a direct comparison was made to identify the influence of the ice covering.
*d) Figure 2 should include the variables, which are used for the result section and please also include a clear definition on which it was measured.
Thank you very much.
Author Response
Dear Reviewer:
Thank you so much for your review and providing us with these insightful comments. We revised our paper by following your comments. We believe the revised paper has been improved a lot.
Please see attached discussion letter.
Sincerely yours,
Jueyi Sui
Author Response File: 
Author Response.docx
