Round 1

Reviewer 1 Report

The topic that was taken up by the authors is interesting from a scientific point of view and important from a practical point of view. As was properly stated by the authors accurate measurements of sediment flushing cone geometry are essential for determining sediment removal efficiency in reservoirs. The aim of the paper is clearly justified. A selected photogrammetric method called the structure from motion method was investigated to determine the sediment flushing cone geometry in an experimental study. The main results are presented and main conclusions are pointed. It should be noted general layout of the article is correct. The authors present all necessary information. The review of the current state of knowledge has been carried out carefully. The selected methods of performing experiments have also been properly described. It is especially important that the authors described their strengths and weaknesses in understandably way. It can also be considered that the way the results are presented is correct. The presented conclusions caused from the research carried out and may be potentially useful for readers.

However, there are minor elements that need improvement. For example: the marks  in Figure 4b are illegible and need to be corrected and different accuracy was used to present the results in Table 4. These shortcomings should be corrected. After applying the indicated changes, the article is suitable for publication.

Author Response

RESPONSE TO COMMENTS

PREAMBLE

The authors would like to express their sincere appreciation for the insightful comments and sound review provided by the referees as well as the editorial office. We have thoroughly revised the manuscript and addressed all comments and suggestions as deemed fit. To further our cause, we have provided below point-by-point responses (in blue). We hope that the revised version is now suitable for publication.

I-                REVIEWERS’ COMMENTS

Reviewer #1

General comments:

The topic that was taken up by the authors is interesting from a scientific point of view and important from a practical point of view. As was properly stated by the authors accurate measurements of sediment flushing cone geometry are essential for determining sediment removal efficiency in reservoirs. The aim of the paper is clearly justified. A selected photogrammetric method called the structure from motion method was investigated to determine the sediment flushing cone geometry in an experimental study. The main results are presented and main conclusions are pointed. It should be noted general layout of the article is correct. The authors present all necessary information. The review of the current state of knowledge has been carried out carefully. The selected methods of performing experiments have also been properly described. It is especially important that the authors described their strengths and weaknesses in understandably way. It can also be considered that the way the results are presented is correct. The presented conclusions caused from the research carried out and may be potentially useful for readers.

Response: We sincerely thank the reviewer for careful reading of the manuscript and constructive comments.  

Minor suggestions:

However, there are minor elements that need improvement. For example: the marks in Figure 4b are illegible and need to be corrected and different accuracy was used to present the results in Table 4. These shortcomings should be corrected. After applying the indicated changes, the article is suitable for publication.

Response: As suggested by reviewer, the correction has been made. Figure 4 was improved. Please see, page 8.

Also, Table 4 illustrates the error rate between the output data from AgiSoft Metashape compared with the manually measured data and the coefficient of determination for the prediction equations (R²) for any SFM model. For more clarify, the sentences were added.  Please see, page 14, lines 374-377.

Author Response File: Author Response.docx

Reviewer 2 Report

The focus of the paper is very important and the investigation was conducted with the necessary scientific rigor. The paper is well structured and well organized. The work is based on excellent experimental study further validated by a numerical analysis and modelling scenario. This is very important for a sound and robust concluding results. Control and monitoring of sediment flushing is an evolving field of research and it is subject to debate and what is reported in the literature is large and vast. We recommend the present paper with fewer revision.

1. Novelty and motivation are not well justified in the introduction.
2. Section 2.5.3 should be improved and amended.
3. What is Cube box test?
4. Please improve the quality of Figure 7 and 8.
5. Data used for preparing the scatterplot of Figure 8 should be described
6. Future recommendation in the conclusion.   

Author Response

RESPONSE TO COMMENTS

PREAMBLE

The authors would like to express their sincere appreciation for the insightful comments and sound review provided by the referees as well as the editorial office. We have thoroughly revised the manuscript and addressed all comments and suggestions as deemed fit. To further our cause, we have provided below point-by-point responses (in blue). We hope that the revised version is now suitable for publication.

I-                REVIEWERS’ COMMENTS
 

Reviewer #2

General comments:

The focus of the paper is very important and the investigation was conducted with the necessary scientific rigor. The paper is well structured and well organized. The work is based on excellent experimental study further validated by a numerical analysis and modelling scenario. This is very important for a sound and robust concluding result. Control and monitoring of sediment flushing is an evolving field of research and it is subject to debate and what is reported in the literature is large and vast. We recommend the present paper with fewer revision.

 Response: We sincerely thank the reviewer for careful reading of the manuscript and constructive comments.  

Minor suggestions:

Comment 1: Novelty and motivation are not well justified in the introduction.

Response: As suggested by reviewer, we tried to justified clearly novelty and motivation in the introduction. Please see, page 2, lines 84-87.

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Comment 2: Section 2.5.3 should be improved and amended.

Response: As suggested by reviewer, the correction has been made. Please see, page 6, lines 196-205.

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Comment 3: What is Cube box test?

Response: In the current research, the cube box test was used to test the accuracy of the SFM method and AgiSoft Metashape software. Therefore, a cube box with known dimensions and volume, was located in the reservoir, overlapping to the sediment surface level, similar to a flushed cone. Then, all of SFM process for determining the topography, were done. For more clarify, a sentence was added. Please see, page 7, lines 228-232.

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Comment 4: Please improve the quality of Figure 7 and 8.

Response: As suggested by reviewer, the correction has been made. the quality of Figures 7 and 8 were improved from 600 dpi to 1200 dpi. Please see, pages 11-12.

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Comment 5: Data used for preparing the scatterplot of Figure 8 should be described

Response: As suggested by reviewer, the correction has been made. Please see, pages 12, lines 305-308.

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Comment 6: Future recommendation in the conclusion.

Response: As suggested by reviewer, future recommendation was added to conclusion section. Please see, page 15, lines 399-401.

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Author Response File: Author Response.docx