Measuring Annual Sedimentation through High Accuracy UAV-Photogrammetry Data and Comparison with RUSLE and PESERA Erosion Models

Round 1

Reviewer 1 Report

Dear Author(s),

Congrats on a very good paper! Overall, the methodology is very well-described and the paper is very clear and has no minuses. Except for some minor spelling errors. Please, find in the attached .pdf my minor comments on your paper. I think it can be accepted with some Minor Revisions. Also, see my comments.

Kind regards!

Comments for author File: Comments.pdf

Author Response

We thank you for your comments.

Attached you will find the detailed responses to all your fruitful comments and concerns

Author Response File: Author Response.docx

Reviewer 2 Report

Dear Editor and Authors,

I have revised the manuscript remotesensing-2213195-peer-review-v1, entitled: Measuring annual sedimentation through high accuracy UAV-Photogrammetry data and comparison with RUSLE and PESERA erosion models. The topic of the manuscript is certainly suitable for the journal and of potential international interest but the manuscript can not be accepted for publication in its present form and a some revisions are request. The main problem of the paper is that it appears confused and low fluid and in many part the methodology applied should be better described. No interesting details about the data specification and study area that show the uniqueness of the problem statement with the hypothesis and findings no in depth discussion, only presenting the results in general manner and often unclear. Also, the Authors should better highlight the novelty of the applied methodology and their points of force. A lot of data is presented, which is either not clear how was obtained and/or discussed in depth. The discussion failed to present a clear story but rather includes several issues which were discussed in a superficial way.

All my comments and suggestions are listed below.

- Page 2, line 92: This is RS? please clarify

- Page 2, line 96: I suggest to also cite the follow papers:

1) Bazzoffi P. “Measurement of rill erosion through a new UAV–GIS methodology,” Ital. J. Agron. 2015, 10, 1–18. doi 10.4081/ija.2015.708

2) Borrelli L., Conforti M., Mercuri M. LiDAR and UAV System Data to Analyse Recent Morphological Changes of a Small Drainage Basin. Int. J. Geo-Inf. 2019, 8, 536.

- I suggest to add in the 2.1. Study area section, some data related to soil types (E.g. USDA classification), also a brief description of the geomorphological setting of the study area should be added in the text.

- The Authors should better specify as were obtained the soil parameters. For example, How many soil samples was collected

-I suggest to add a figure with a flowchart of the methodology applied. This could help the reader to better understand the several steps of the work.

- My opinion is that the in the results section many part of the text are not results but material and methods, therefore, I suggest to rewrite this section.

-The discussion failed to present a clear story but rather includes several issues which were discussed in a superficial way. Therefore, this aspect should be better focused in the discussion section.

-The authors must emphasize the novelty of the their research and that their work can be successfully used in other regions and settings, because this justify the publication in an international journal.

Author Response

We thank you for your comments.

Attached you will find the detailed responses to all your fruitful comments and concerns.

Author Response File: Author Response.docx

Reviewer 3 Report

This paper attempt to use the new advances in remote sensing and UAV photogrammetry for measuring with high accuracy the annual sediment yield resting on a retention dam in a complex mountainous Mediterranean-type basin. This is very meaningful and useful. This paper has a guiding significance for understanding the occurrence and change of soil erosion and sediment delivery. However, the authors need to do much more to improve the paper and make a good scientific story. Kindly, see below for detailed comments:

 1 In the abstract, the methods of UAV processing for soil erosion in this study should be introduced in detail. The existing problems and future directions need to be described in detail. The most important thing is that the differences between models and why they occur should also be described in detail. Keywords, “drone” is inappropriate, UAV-derived point cloud or point cloud may be appropriate.

2 Introduction, the purpose and significance of effective methods for soil erosion with UAV survey need further description. A large amount of space introduces that the traditional model is not suitable for this paper.

3 Materials and Methods, Study area, the meteorological data should be added, especially rainfall.

4 Line 159, Why the flight monitoring time is inconsistent.

5 Line 272, the C-factor of 223: Olive groves and 243: Land principally occupied by agriculture, with significant areas of natural vegetation probably unscientific. The C-value and P-value cause the inaccuracy of the model, which should be the focus of this paper.

6 2.3. The Pan European Soil Erosion Risk Assessment (PESERA) model. I think most of the contents of 3.1 can be put here or appendix. Because most of the parameter selection is based on research literature. Also, 2.4 in the same way.

7 Check if formula 4 is correct.

8 Results. I think the importance of the results should be placed on UAV photogrammetry and measurement of the actual deposition at the retention dam. Therefore, 3.3 should be put first. More research results rather than research methods need to be added. In particular, the migration direction of sediment and reasons for differences between different years. What is the spatial range of soil erosion observed by UAV in this paper? The PESERA and RUSLE model should be the assessment of soil erosion in the whole basin, so how do you cross-compare? In short, I think there are still many UAV results that need to be added, and the focus should not be on the evaluation of the PESERA and RUSLE models.

9 Figure 1, Longitude and latitude grid should be unified in full text. The UAV flight area should be marked. Figure 2, Why not add a panoramic view of the dam taken by UAV? Figure 3, Why 3a is so blurred? Please add a north arrow. Figure 9, it is unnecessary to add a graph for a single value. Figures 10 and 11, the units of scale bar and legend should be added.

10 Tables 5 and 6, the physical-chemical and textural crusting should be marked in a table row and column.

11 Conclusions, please highlight the significance and guiding role of this study.

12 Carefully check the paper format and upper and lower marks.

Author Response

We thank you for your comments.

Attached you will find the detailed responses to all your fruitful comments and concerns

Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

This paper meets the publishing requirements of Remote Sensing.