Hydraulic Conditions of Incipient Rill by Raindrop-Induced Overland Flow on Steep Slopes of Sandy Soil
Round 1
Reviewer 1 Report
1. What is the Innovativeness in the study?
2. Which model you had study for evaluation?
3. Which control measures you adopted for your study?
4. Limitations in the study?
5. Have you compared your work with other researchers?
6. Any assumptions have you considered in your work ?
7. How the soil classification is decided ?
8. Have you consider any tractive force actions in your work/study?
9. Highlight the governing equations used while performing analysis
Major Revision
Author Response
Thank you for your review and valuable comments.
The manuscript was improved significantly based on your comments.
English language of this manuscript was revised by research expert in the United States.
If this manuscript needs additional revision, please do not hesitate to give comments.
Author Response File: 
Author Response.docx
Reviewer 2 Report
Reviewer: This paper studies the generation and development of rills on steep slopes. A very large number of studies have been conducted on this area, and this paper does not reflect enough of the main innovative points. Moreover, the description of the experimental design, the presentation of the experimental data, and the discussion of the experimental results are not clear. Overall, this manuscript needs major revised and improved.
Abstract:
Page1, line 12: This paper focuses on the development of rills on steep slopes, and the study of loamy soils is not mentioned in the paper.
Introduction:
Page 1, line 35: Please provide specific data on the amount of increase in rill erosion to demonstrate the severity of rill erosion.
Page 2, line 9: What is increasing? Is it the number, length or depth of rills? Please elaborate clearly.
Page 2, line 17: Rill erosion is more sensitive to hydrodynamic characteristics
Rainfall simulation:
Page 3, line 9: Is it scientific to replace the long hillslope of 3.2 m with a 0.8 m length of soil box? Does it articulate well in the experiment and is the 0.8 m length sufficient to reflect the formation and development of the rills?
Page 3, line 10-11: Why set the inflow supply only in the second and third segments?
Page 3, line 12: What is the duration of rainfall?
Page 3, line 11-12: What is the basis for setting the slope and rainfall intensity?
Page 3, line 11-12: What is the rational method?
Page 3, line 15-16: Please describe the dye-tracing method in detail, and add the specific process of measuring runoff velocity.
Page 4, line 25: Please note the consistency of the format.
Page 5, line 3: N/m2
In general, there is a lack of description of replicates and statistical methods used in the study. Whether the experiment has been repeated? The formulas are listed without the corresponding explanations, like the threshold values and meanings of the hydrodynamic parameters. How are some parameters such as runoff coefficient, unit flow rate calculated? Please list the calculation formulas. And there are also some errors in the formulas, please correct them.
Results and discussions
Page 5, line 16: Experimental record data should be provided to illustrate the increasing extent of flow velocity and rill expansion, like depth, length, width of rills.
Page 5, line 27: Runoff coefficient decreased with increase of rainfall intensity and inflow rate is unreasonable.
Page 6, line 1: What is the cause of the least runoff coefficient of the 2.4 m segments?
Page 6, line 9-10: Whether such a comparison is made in the context of the experimental setup and soil conditions. If not, then the comparison results are not meaningful.
Page 6, line 11-12: You did not do a control experiment without raindrop impact, so it is lacking in argument to draw this conclusion.
Page 7, line 5: What does hesitant mean? The Reynolds number is used to determine the flow state of overflow and is used to distinguish between laminar and turbulent flow, which should be analyzed in this study.
Page 9, line 2: No significant difference analysis was performed on the data.
Page 9, line 17: Why the relationship between sediment yield and sheer stress is not represented?
Page 9, line 22: Whether the critical stream power and critical unit stream power estimated 0.15W/m2 and 0.024m/s applies to all slope and rainfall intensity conditions.
Page 10, line 5: Why not use the steady flow velocity for prediction? Or separate the stages before and after the appearance of rills. Will rill erosion be overestimated if maximum velocity of overland is used?
Page 11, line 1-10: In the following comparison, are the rainfall intensity and slope length in the experimental setup of other researchers consistent with those in this study? Both are important factors influencing the formation and development of fine grooves, but they are not mentioned in the Table 3.
In this section, the authors describe some experimental results, but do not provide further analysis of these results, as well as an elaboration of the causes.
Conclusions:
The conclusion section should be more concise and not a repetition of the discussion section, and should present several representative and concluding points.
In addition, all the figures are not clear enough, please reupload.
Author Response
Thank you for your review and valuable comments.
The manuscript was improved significantly based on your comments.
English language of this manuscript was revised by research expert in the United States.
If this manuscript needs additional revision, please do not hesitate to give comments.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
Revision is appropriate
Reviewer 2 Report
all the questions were well revised.
