Overflow-Induced Breaching in Heterogeneous Coarse-Grained Embankment Dams and Levees—A State of the Art Review

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This review article synthesizes recent experimental research on the breaching of noncohesive embankment dams and levees caused by overflow, with a specific focus on coarse-grained soil materials. The paper is well organized and of good significance. The paper can be accepted after a minor revision. The comments are listed as follows:

1. The content of the paper is rich. It is recommended that the author add some sub-headings and summaries to help readers better understand the paper.
2. A section should be added to discuss the future research directions.
3. The conclusions should be more summarized and straight forward.

Author Response

Comments 1: The content of the paper is rich. It is recommended that the author add some sub-headings and summaries to help readers better understand the paper.

Response 1: We appreciate the reviewer’s suggestion. In response, we have revised the manuscript to include sub-sections within each main section to enhance readability. Additionally, we have added summary sub-sections at the end of Sections 4 through 7 to help readers better understand the key findings.

Comments 2: A section should be added to discuss the future research directions.

Response 2: Thank you for your suggestion. We have revised and expanded the final section titled "Conclusions and Research Gaps" to better highlight future research directions. We hope this addresses your comment.

Comments 3: The conclusions should be more summarized and straight forward.

Response 3: Thank you for your suggestion. We acknowledge the importance of concise conclusions. However, due to the extensive range of studies reviewed and the complexity involved in integrating their findings, we believe the current level of detail is necessary to accurately reflect the key insights.

Reviewer 2 Report

Comments and Suggestions for Authors

The review is comprehensive and well-organized, and it presents valuable insights. To further improve the flow, adding brief summaries or subheadings to help guide readers through the more complex sections is suggested.  
The experimental and numerical analyses are clearly explained and detailed. Including additional information on specific methodologies—such as scaling criteria and instrumentation accuracy—could also be helpful for enhancing transparency and enabling others to reproduce the work more easily.  
The paper brings attention to conflicting findings regarding soil erodibility (e.g., coarser vs. finer materials). A more in-depth discussion of these differences, perhaps with a suggested framework for understanding them, could add even greater value to the review.  
The conclusions are strong and well-supported. Adding a brief section that connects the findings more directly to real-world dam safety applications—such as model selection or monitoring strategies—could make the review even more practical and useful for engineering professionals.

Author Response

Comments 1: To further improve the flow, adding brief summaries or subheadings to help guide readers through the more complex sections is suggested.  

Response 1: We appreciate the reviewer’s suggestion. In response, we have revised the manuscript to include sub-sections within each main section to enhance readability. Additionally, we have added summary sub-sections at the end of Sections 4 through 7 to help readers better understand the key findings.

Comments 2: Including additional information on specific methodologies—such as scaling criteria and instrumentation accuracy—could also be helpful for enhancing transparency and enabling others to reproduce the work more easily. 

Response 2: Thank you for your valuable suggestion. We fully agree on the importance of including detailed methodological information to enhance transparency and reproducibility. However, we have tried to strike a balance, as other reviewers noted the article’s length as a limitation. Given that the manuscript has already expanded due to the inclusion of summary sub-sections, adding further methodological details to the main text would be very difficult. However, we would like to emphasize that during the review of each article, we were very conscious of extracting and presenting all available and most relevant information regarding methodologies. Additionally, we remain open to including supplementary material if the journal allows it and you think it is necessary.

Comments 3: The paper brings attention to conflicting findings regarding soil erodibility (e.g., coarser vs. finer materials). A more in-depth discussion of these differences, perhaps with a suggested framework for understanding them, could add even greater value to the review.  

Response 3:  Thank you for your thoughtful comment. We agree that conflicting findings on soil erodibility are a key issue. In the original manuscript, we attempted to discuss possible reasons behind these discrepancies. In the revised version, we have added additional text to further clarify and help discern the contradictions across different studies. Please refer to lines 512–525, where this discussion has been expanded.

Comments 4:  Adding a brief section that connects the findings more directly to real-world dam safety applications—such as model selection or monitoring strategies—could make the review even more practical and useful for engineering professionals.

Response 4: Please refer to the new text at the end of the conclusions, which expands the discussion on how the identified research gaps may link with practical engineering applications.

Reviewer 3 Report

Comments and Suggestions for Authors

The proposed review article presents a relevant contribution to the field of hydraulic and geotechnical engineering, by focusing on the analysis of the failure processes of dams and dikes built with heterogeneous non-cohesive soils. The topic is of great practical importance, considering the history of dam collapses with severe socioeconomic and environmental consequences. The text demonstrates clarity in contextualizing the existing gap in the scientific literature, as there is a relative scarcity of physical models and robust understandings for heterogeneous and well-graded soils. The review of 160 references indicates a considerable effort in bibliographic compilation and analysis, which suggests a good basis and a representative overview of the state of the art.

Suggestions for improvements so that the work has greater scientific impact:

- It would be interesting to include a summary table or chart comparing the different experimental approaches reviewed.

- Discuss possible paths for the development of predictive physical models aimed at heterogeneous soils, based on the identified gaps.

- Consider in the introduction an important work on the collapse of a dam in Brazil (one of the biggest disasters in the world in this sense). (see https://doi.org/10.1007/s12665-024-11428-1).

Author Response

Comment 1: It would be interesting to include a summary table or chart comparing the different experimental approaches reviewed.

Response 1: Thank you for your valuable suggestion. We fully agree on the importance of including a chart comparing the different experimental approaches. However, we have tried to strike a balance, as other reviewers noted the article’s length as a limitation. Given that the manuscript has already expanded due to the inclusion of summary sub-sections, adding an additional chart to the main text would be very difficult. However, we remain open to including supplementary material if the journal allows it and you think it is necessary.

Comments 2: Discuss possible paths for the development of predictive physical models aimed at heterogeneous soils, based on the identified gaps.

Response 2: Please refer to the new text at the end of the conclusions, which expands the discussion on how the identified research gaps may link with practical engineering applications.

Comments 3: Consider in the introduction an important work on the collapse of a dam in Brazil (one of the biggest disasters in the world in this sense). (see https://doi.org/10.1007/s12665-024-11428-1).

Response 3: Please refer to lines 41-43.

Reviewer 4 Report

Comments and Suggestions for Authors

Abstract

You could remove "To complete this document, one hundred and sixty references have been reviewed.", since this is not a relevant or quantifiable piece of information. Is this a lot, enough, too much?

line 40: correct: "September 11^th"

As a general conclusion about this paper is that it is too extensive. It should be more synthetically presented the literature review, without too many in depth explanations and charts and then a discussion about the findings. 

Author Response

Comments 1: You could remove "To complete this document, one hundred and sixty references have been reviewed.", since this is not a relevant or quantifiable piece of information. Is this a lot, enough, too much?

Response 1: Thank you for your suggestion. Indeed, it is ambiguous. Please refer to the new version of the abstract where this setence was removed from.

Comments 2: line 40: correct: "September 11^th"

Response 2: Corrected in the new version of the manuscript. Please refer to lines 40-41.

Comments 3: As a general conclusion about this paper is that it is too extensive. It should be more synthetically presented the literature review, without too many in depth explanations and charts and then a discussion about the findings.

Response 3: We appreciate your suggestion. However, we have aimed to strike a balance, as other reviewers requested more detailed analysis. To help address your concern, we have included summary sub-sections at the end of Sections 4 through 7 to synthesize the key findings. We hope this structure facilitates a clearer understanding while maintaining the depth required by the subject matter.

 

Reviewer 5 Report

Comments and Suggestions for Authors

This is a review article.
It synthesizes recent experimental research on the breaching of non-cohesive embankment dams and levees caused by overflow. The aim of the paper is to gather and analyze the most relevant and recent experimental research on embankment breaching, with a particular focus on coarse-grained soil materials. 
The paper sums up the main breach models and analyses the effect of compaction, hydraulics and geometry.
Finally it draws conclusions by summing up the main factors affecting soil erodibility.
The paper also identifies the main research gaps.

The paper is relevant for the field and is presented in a well-structured manner.
In my opinion the gap in knowledge identified should be better discussed.
Lines 114 -124: different type

Author Response

Comments 1: In my opinion the gap in knowledge identified should be better discussed.

Response 1: Please refer to the new text at the end of the conclusions section, which expands the discussion on how the identified research gaps may link with practical engineering applications.

Comments 2: Lines 114 -124: different type

Response 2: Corrected in the new version of the manuscript, that you very much.