Prediction of Shallow Failure on a Slope Using Volumetric Water Content Gradient Characteristics

Round 1

Reviewer 1 Report

All comments are listed in the attached file.

Comments for author File: Comments.docx

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

Review of “Prediction of Shallow Failure on a Slope Using Volumetric Water Content Gradient Characteristics”

This paper investigated the capability of using volumetric water content (VWC) gradient to predict shallow failure that occurs on a slope due to rainfall infiltration. Flume tests were conducted to analyze the characteristics of the VWC gradient in the event of failure. The paper is well written, and the topic of the study meets the scope of Applied Sciences. Prior to accept this paper, however, the authors may want to address the following issues.

 

General comments:

1) Though the VWC gradient is an important indicator of shallow failure, other factors, such as soil texture, vegetation type and coverage, topographic features of surface may also affect the occurrence of shallow failure. It will be helpful if these factors are investigated or discussed in the paper.

 

2) It is known that it is unrealistic to install sensors on all hillsides. The readers may wonder if they do not deploy sensors, how they can predict shallow failure. In addition to ground VWC measurements, soil moisture (i.e., the VWC mentioned in the study) can also be obtained from model simulations (e.g., Li et al., 2019, DOI: 10.1002/joc.6549) and satellite retrievals (e.g., Zeng et al., 2015, doi.org/10.1016/j.rse.2015.03.008), and there are already many VWC datasets released to the public. Do the authors think these products are able to play an important role (or have the potential) in shallow failure monitoring?

 

Other specific comments:

1) Introduction: please reduce the number of paragraphs appropriately, and some of them can be merged. Moreover, please briefly introduce the structure of the paper at the end of this part.

 

2) Figure 1: in the figure, it shows y=24.397x, and thus the slope should be 24.397. Why you state VWC gradient=0.24?

 

3) Figure 2: I cannot find the corresponding description of Figure 2 in the content.

 

Figures. 3-7: it is better to enlarge the font in these figures to make them clearer. “Times New Roman” font is recommended (also for other figures), and this suggestion is particular for Figures 4, 5 and 7.

 

4) Caption of Figure 4: where is the description of (e) and (f)?

 

Caption of Figure 6: delete “and”.

 

Caption of Tables 3 and 4: they are too simple, please specify.

 

Table 4: it is better to change “0.2<” to “>0.2”.

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Thank you for applying all my suggestions and answering my questions. I believe the paper is now easier to read and the data is presented in a simple clear way.

The authors’ results may have practical applications – we do have a satellite imaging, which could obtain data on soil water content, however, this kind of experiments show, for example, which soil depths are significant in research of shallow soil failures.  

The article structure is not a usual one (introduction, methods, results, discussion, conclusions). The journal’s Editor should decide if it could be published in this form or the authors should reshape the paper.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

The authors have addressed most of my comments and the paper has been improved. Before the paper being published, the following minor comments should be addressed further.

For my first comment, the authors said “We agree that factors such as soil texture, vegetation type and coverage, and topographic features of surface affect the occurrence of shallow failure. We are trying to identify the influence of these factors through continued research. In this study, however, the influence of these factors was not considered”. It is no problem that the authors did not consider these factors that may influence the occurrence of shallow failure in their study, but it is necessary to add some appropriate discussion regarding this issue in the manuscript.

For my second comment, the authors said “If VWC can be identified using an indirect method even though it cannot be measured at an actual site, we think that it can be used for failure prediction.”. How can you determine VWC using an indirect method? Which method can achieve this purpose? The authors also said “As an example, according to our survey, only the values at a depth of approximately 10 cm are valid when measuring the water content through satellite imaging. We believe that the water content information at this depth is irrelevant to shallow failure prediction.”. It is understandable for the fact that satellite soil moisture product can only represent VWC at topsoil of about 0-5 cm, but model simulations can provide VWC at different depths (e.g., the root zone VWC). Can such data be applied in shallow failure monitoring (perhaps the grid resolution of model-based VWC is a potential problem)?

Author Response

Please see the attachment.

Author Response File: Author Response.docx