Assessment of Net Erosion and Suspended Sediments Yield within River Basins of the Agricultural Belt of Russia

Round 1

Reviewer 1 Report

General comment

This review is on the article “Assessment of net erosion and suspended sediments yield within river basins of the agricultural belt of Russia”

In general, I found the article is an informative, and timely requirement, but it needs to be improved in many aspects.  Therefore, I proposed the paper should be considered for publication after major revision.

I would propose a major revision and will explain this in more detail by going through the article chapter by chapter:

Abstract

Abstract need to be improved as it does not indicate the research problem correctly. I find some mismatching in the structure of the abstract.

Line 31 to 33 says, “It is possible to conclude that the proposed method of SEA/Balance can be successfully applied to river basins of the agricultural zone of the East Russian Plain and whole European part of Russia”, there is no such a conclusion in the conclusion section of the paper. I feel there is not enough evidence in the study to make such a conclusion.   

Introduction

The introduction is well written, but still, I feel that the authors unnecessary pay more attention to writing much more information on sediment characteristics (Line 92 to 131), if it can be summarized into one or two paragraphs, the introduction can be further improved. 

Lines 38-46 important references are missing

Material and Methods

Study area

This section is a bit confusing for me as includes the selection criteria of the study area. I feel this is a part of your methodology, so I believe that by including this part into the methodology the study area can be improved. Also, provide a piece of valuable information about the study area.

If the table 1 and 2 are taken from the other sources, you can provide the source and keep them in the study area. However, if you generated them through the study please include them in your results section.

Methodology

It needs the dramatically improve the methodology section. It is mixed with methodology and data section as well. Therefore, my recommendation is to rearrange the methodology section into bellow three sections,

·         Study Area

·         Data

·         Methodology

Also, please remove the unnecessary explanation provided in the current methodology section to improve the readability of the paper.

Results and discussion

Although this section is well written, this section should be separated according to the MDPI paper structure,

·         Results

·         Discussion

Conclusion

Conclusion is OK

Author Response

Thank you very much for the review of our article and the generally positive attitude towards it. In the course of its correction, we tried to take into account most of your comments. Our detailed answers are given below. (highlighted in italics ).

Abstract

Abstract need to be improved as it does not indicate the research problem correctly. I find some mismatching in the structure of the abstract.

Line 31 to 33 says, “It is possible to conclude that the proposed method of SEA/Balance can be successfully applied to river basins of the agricultural zone of the East Russian Plain and whole European part of Russia”, there is no such a conclusion in the conclusion section of the paper. I feel there is not enough evidence in the study to make such a conclusion.

Thank you for your comment. Agree with remark. Since the studied river basins are located within the East Russian Plain, we cannot state that the results obtained can be valid for the entire European part of Russia. This changes have been made to the "Abstract" section (line 32).

Introduction

The introduction is well written, but still, I feel that the authors unnecessary pay more attention to writing much more information on sediment characteristics (Line 92 to 131), if it can be summarized into one or two paragraphs, the introduction can be further improved. 

Lines 38-46 important references are missing

Thank you for your comment. Added references(lines 41, 43) in the first two paragraphs and shortened the description of the coefficients that evaluate sediment connectivity(lines 91-113).

Material and Methods

Study area

This section is a bit confusing for me as includes the selection criteria of the study area. I feel this is a part of your methodology, so I believe that by including this part into the methodology the study area can be improved. Also, provide a piece of valuable information about the study area.

If the table 1 and 2 are taken from the other sources, you can provide the source and keep them in the study area. However, if you generated them through the study please include them in your results section.

Agree with comment. Criteria for selection of test river basins should be located in the methodology section(lines299-314).

Tables 1 and 2 were created by us in the course of this study to characterize the study area either on the basis of freely distributed data or on the basis of data obtained by us earlier, therefore we would like to leave these tables in this section since they provide a detailed natural and anthropogenic characterization of the study area.

Methodology

It needs the dramatically improve the methodology section. It is mixed with methodology and data section as well. Therefore, my recommendation is to rearrange the methodology section into bellow three sections,

• Study Area
• Data
• Methodology

Also, please remove the unnecessary explanation provided in the current methodology section to improve the readability of the paper.

Agree with the comments. Restructured the section in accordance with the comments. Swapped the "Data" and "Methodology" sections. We tried to shorten some explanations in the methodology section. For example, the paragraph explaining the SDR values after Table 6 has been removed.

Results and discussion

Although this section is well written, this section should be separated according to the MDPI paper structure,

• Results
• Discussion

Thank you for your comment. We agree with the reviewer that the “Results and Discussion” section should be divided into two sections “Results”, “Discussion”.

Conclusion is OK

Reviewer 2 Report

The authors compared two models, namely the WATER/SEDEM and the SEA/Balance model to assess the net erosion and suspended sediment yield within river basins. The research topic fits well with the scope of the journal. My main comments are as follows

1. It is recommended to include the detailed information of data sources, such as DEM, land use map etc. In addition, it would be helpful to include the data resolution and time of acquisition, especially for the land use/land cover types.

2. The two models results are quite different for several river basins, for instance, the Atkarka river basin. It would be helpful to try to explain the model discrepancy, i.e., what is the main cause of the difference.

3. Was there land use/cover change for the river basins? Is it considered in the model?

4. The units in equations and some definitions are not very clear. For instance LS2D is commonly defined as slope length and steepness.

5. There are typos spreading in the manuscript. The authors are recommended to conduct a thorough proofread. For instance, the use of semicolon in the manuscript is not accurate in most of the place.

Author Response

Thank you very much for the review of our article and the generally positive attitude towards it. In the course of its correction, we tried to take into account most of your comments. Our detailed answers are given below. (highlighted in italics and blue).

1. It is recommended to include the detailed information of data sources, such as DEM, land use map etc. In addition, it would be helpful to include the data resolution and time of acquisition, especially for the land use/land cover types.

The global publicly available SRTM SIR-C elevation model with 1 angular second resolution of, which is close to 25x25 meters cell size grid of the study area, was used to create elevation models for the test river basins.

Remote sensing data from Landsat 5 was used to create land use maps. Landsat 5 and Landsat 8 data were used to determine land use dynamics in the Sterlya river basin. The resolution of the original Landsat data was added to the article(1 angular sec).

This information about all sources of spatial information, their resolution, dates of receipt and processing is given in more detail in section 2.2.

2. The two models results are quite different for several river basins, for instance, the Atkarka river basin. It would be helpful to try to explain the model discrepancy, i.e., what is the main cause of the difference.

Yes, we agree that for some river basins there are large differences in the amount of suspended sediment yield obtained by different models. At the same time, it does not seem to us that large differences in deviations are obtained for the Atkarka test basin(SEA/Balance methodology -70%, WATEM/SEDEM -51%), there are river basins with large differences in biases, for example (Nurminka, Sterlya, Birla) Table7.

In our opinion differences can be explained by the fact that the Watem/Sedem model was not calibrated for the natural conditions of the study region due to a lack of initial data. Therefore, when using it, positive biases were obtained for some test river basins (Nurminka, Sterlya, Birla), while negative biases were obtained for the same river basins when using the SEA/Balance model, witch more corectness.These explanations are included in the article (lines 518-523)

3. Was there land use/cover change for the river basins? Is it considered in the model?

Since we only had relatively modern data on sediment yield for one station, on the Sterlya River, the analysis of the impact of land use dynamics on sediment yield was performed only within one test basin.

4. The units in equations and some definitions are not very clear. For instance LS2D is commonly defined as slope length and steepness.

Thank you for your comment. We have redefined LS2D in accordance with your recommendations(lines324-325). Units of measurement are given in accordance with the previously published WATEM/SEDEM methodology. (Van Rompaey, A.J.J.; Verstraeten, G.; Van Oost, K.; Govers, G.; Poesen, J. Modelling Mean Annual Sediment Yield Using a Distributed Approach. Earth Surf. Process. Landforms 2001, 26, 1221–1236, doi:10.1002/esp.275.)

5. There are typos spreading in the manuscript. The authors are recommended to conduct a thorough proofread. For instance, the use of semicolon in the manuscript is not accurate in most of the place.

Thank you for your comment. We tried to make an additional improvement of the English language in the article.

Round 2

Reviewer 1 Report

It can be recommended to publish the paper in its current form.