Evolution of the Relationship between Runoff and Sediment Transport during Flood Event in the Chabagou Watershed of the Loess Plateau
Round 1
Reviewer 1 Report (Previous Reviewer 2)
The manuscript was resubmitted, therefore I expected higher effort of the authors to increase its quality. However, the main mistakes remained. I don’t feel qualified to judge about the English language; nevertheless, the scientific terminology is not correct. Before the publishing of article, it is necessary to consider:
Abstract
· What does P mean?
Introduction
· Why do you use ’7.26’ to mention the main flood and describe it with different values as is in the material and methods? Just mention the highest flood was on 26 July 2017.
· Why do you mention years 2017 and 2006 there without any connection between?
Material and methods
· The reference for the Figure 1 is missing in the text.
· Figure 1: what is CP?
· Uniform the format of units in the whole manuscript (mixed m3.s-1 and m3/s)
· Replace ‘accorded’ by ‘recorded’.
· There are 2 different set of data sources compared - how can you compare 20 and 18 years and 79 and 22 floods? At least, the range of years should be the same.
· NDVI data do not cover the whole PD-I period.
· ‘Runoff amount’ is not correct expression.
· The related units write into brackets or separate by comma at the end of definition. There is no need to mention that the units are…
Results
· Line 157: “In PD-II, the greatest value of SY was 101.23×104 t, with a change rate of -60.1%.” What do you compare?
· Why do you always mention two periods in the sentences (e.g., lines 168-169: “…the frequency of flood event 168 in two periods was…”) if you compare only 2 periods? In such a case should be used “both” instead of “two”.
· Table 2: Add the number of floods in each period. The disproportion is given by the high difference in the analysed periods. How can you compare 7 floods with 1?
· Uniform the abbreviation for flood “7.26” in the whole manuscript. Later it is mentioned like NO. 100.
· Line 224: “As data display…” Which data?
Discussion
· Line 247: “In PD-II, their correlation coefficients were, respectively.” It doesn’t have a sense.
· How the SDM was determined?
· Line 298: What does mean “vegetation construction”?
· Lines 311-312: “Figure 7 also demonstrates the function of check dam.“ How does it demonstrate the function of dams? There are only their positions.
· I don’t see any reason to use NDVI for the analysis. Standard land cover/land use analysis is enough in case it is properly done.
· Figure 9: legend is missing.
· Lines 370-372 only doubt data from table 4 without analysis. Delete it and leave rest of the paragraph with data analysis.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report (Previous Reviewer 3)
Research on flood event is one of the most important parts to study runoff and sediment transport. The paper represents a generally runoff and sediment change study of typical watershed in the Loess Plateau, and proposes the important and interesting influence factors. What’s more, by comparing flood events, the change characteristics of runoff and sediment transport can be seen more clearly. However, there are some detailed comments that the author should attention.
The using of words and grammar, for example,
line 50 “He determined that the flood event in 2013 had a changing pattern of slow rise and slow fall, …” the word “determined”.
line 79 “the watershed is in a symmetrical shape”
line 82 “The climate in the watershed is dry continental with minimal rain”. The word “minimal” is appropriate or not.
line 108 “The time series of GIMMS NDVI data set belongs from 1981 to 2015, and the spatial resolution is 8 km.” The method of application of the word “belong”.
The full text should use the same format, line 98 “m3/s and kg/m3”, which is different from other formats.
Please check the full text and correct them.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report (Previous Reviewer 2)
I appreciate a work done by authors. However, I am confused due to the inappropriate presentation of results. Authors themselves point up presentation of incomplete data sources. In such case, the results should not be presented in the current form. The manuscript could be published only by the deep analyse of flood events without mentioning the effects of NDVI.
Author Response
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Author Response File: Author Response.pdf
Round 3
Reviewer 1 Report (Previous Reviewer 2)
Currently presented results are adequate, even some other analysis could be done. However, I recommend to accept the manuscript.
This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.
Round 1
Reviewer 1 Report
1. In the abstract, result 1 "compared with PD-I, PD-II has a significant increase in RA and a 48.91% decrease in SY", which contradicts the statement of result 2 "RA and SY have a linear relationship". Result 3 "P's contribution to flood events RA and SY was greater than other relevant indicators in both periods", indicating that PD-II vegetation restoration measures are inferior to P, which is contradictory to result 5.
2. It can be seen from Table 2 that P and RI in the two periods are negatively correlated, but the relationship between RI and SY is more consistent; USLE mainly uses rainfall energy instead of rainfall as a parameter; however, this study adopts P as the main discussion, which violates the academic consensus of RI-based.
3. In Figure 2, SY changes with PF at four classifications, sample size in PD-II is obviously insufficient in the category of high peak flow (>100 cms).
4. Figure 3. The relationship between RA and SY in two periods, the data with PD-II RA greater than 200 has only two points, and the correlation obtained by an extreme value (>800) is not representative.
5. The interpretation rates of the fitting curves of the relationship between PF and SC in Figure 4 are only 35% and 45%, respectively; in particular, the persuasiveness of PD-II is not enough.
6. The construction of dams is a method of river management, mainly to prevent near-bank collapse, and vegetation restoration is mainly to protect slopes and prevent surface soil loss. The location and function of soil and water conservation configuration of the two are different, so they should not be used as the main treatment to compare and analyze the sediment yield.
7. Nature is a black box and multivariate analysis should be used. Figure 5 uses simple correlation analysis to discuss the influence of precipitation-related indicators on hydrological factors, which cannot solve the problem.
8. "This section is not mandatory but can be added to the manuscript if the discussion is unusually long or complex." should be deleted in the conclusion.
Author Response
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Author Response File: 
Author Response.docx
Reviewer 2 Report
A manuscript deal with highly important problem within the world. A presented topic of runoff, sediment transport and flood events are interesting for hydrologist, hydraulics, water and landscape mangers. Therefore, the manuscript has a high potential to be interesting for readers of Sustainability. However, it has several weaknesses in the current for. Following points should be consider before the publication:
· English language editing - several sentences are hard to read and should be reviewed. It also includes review of structure, e.g., line 151 or lines 362-363
· What does “7.26” means? It is nowhere explained.
· It is not common to start subsection by equation - line 123
· There is no information if the check dams were or are going to be clean after the filling up. It is important to know for the future prediction and conservation of the area. Also, it would be nice to have better comparison between the storage capacity of the check dams and sediment yield in the area. It is written only in general, and readers have to find the effect of check dams in area by themselves.
Author Response
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Reviewer 3 Report
The paper represents a generally runoff and sediment change study of typical watershed in the Loess Plateau, and proposes the important and interesting influence factors, such as erosion dynamics. However, some important issues must be clarified before publication. And detailed comments are listed as followed.
1. The title in Line 152 misspelled.
2. In Table 1 (line 168), the number of digits for runoff amount and sediment yield are reserved to two decimal places, but only one digit is reserved in some places in the text, such as line 187 to line 193, please refer to the similar questions in the full text.
3. Please check again, when the abbreviation appears for the first time, whether there is a full name corresponding to the abbreviation.
4. The color of the legend in Figure 7 is not very distinguishable. It is recommended to use different colors.
5. What is the relationship between Line 362 and 363 and articles？
6. What do the two colors in Figure 5 mean, and what are the significance levels?
7. The description of the study area should be strengthened to clarify the country and region.
8. The conclusion is not general enough; it is recommended to show only the main conclusions.
Author Response
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Reviewer 4 Report
A strange mannerism was presented in the article. A lot of articles by Chinese authors were cited (which is not surprising considering the area of research), but a lot of basic papers by American and European authors were definitely omitted (except for a few). It seems that the authors do not appreciate the scientific output of non-Chinese authors. As a result, the authors of the article use simple rectilinear (sometimes power) relationships, whereas water runoff and sediment yield are of a much more complex hydraulic and hydrodynamic nature. The calculated equations and the observed regularities do not add anything new to our current knowledge of the sediment transport during floods. A very serious shortcoming at the outset is the lack of information about the input data. There is no information whether the precipitation data, rate of sediment transport etc. refer to seconds, minutes, days or perhaps weekly intervals. Therefore, it is difficult to assess the value of the obtained results. The information on the Yellow River Basin Hydrological Yearbook adds nothing to the understanding of the input data. Probably the observational series are valuable, but no new elements were extracted from these data to enrich our current knowledge. The quoted equations according to the Chinese authors are not applicable to Euro-American studies. Hence, it is difficult to compare the obtained results with the results presented so far in the world literature. The non-coordination of fluvial transport observation periods (1970-1990 and 2006-2018) with satellite data (NDVI, 1981-2015 and 2000-2020) is also a disadvantageous application of these comparisons.
Author Response
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Round 2
Reviewer 1 Report
Extreme rainfall is the focus of this study. In order to verify the representativeness of extreme rainfall, the authors removed the extreme value and re-fitted the equation, which was not convincing enough for academic research data processing.
Author Response
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Reviewer 4 Report
The authors acknowledged me about their shortcomings, but they did not adjust any of the comments, they did not include anything. They made numerous corrections to their calculations that were due to their own errors or that were pointed out by other reviewers. I get the impression that the authors are relatively young researchers, since they are unable to use the suggestions given to them to improve the article. And as they themselves wrote "they will use them in the next article". However, I do not think that this will happen because in two previous articles (https://doi.org/10.1038/s41598-021-95111-6 and https://doi.org/10.1002/hyp.14486) they have the same and similar shortcomings. Therefore I still think that the article should be rejected,
Author Response
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Round 3
Reviewer 4 Report
