Local Factors Controlling Gully Development in a Mediterranean Environment

Round 1

Reviewer 1 Report

I do not think the study is meaningful since only one gully was mornitored for four years. So, the determined local factors controlling gully development is not reliable. As we known, the factors influencing gully erosion is very complicated. Authors stated that the main factors that seem to control the spatial variation of soil erosion are the soil penetration resistance, slope, slope shape, and vegetation cover. This conclusion has been reported by lots of researchers. In a word, I must reject this MS given the little data for analyzing influencing factor of gully erosion.

Author Response

The authors have taken into consideration the reviewer's comments, and the changes in the article (underlined in yellow) seek to meet the suggestions considered.

Reviewer 2 Report

General comments

This paper investigated the field gully (morphology, soil, vegetation) between 2015 and 2019, and quantitatively analyzed controlling factors of change of gully width and depth. Gully erosion is the most aggressive erosion type but understanding of gully erosion mechanism is still lack, which need to start from the perspective of controlling factors. The paper obtained valuable long-term scale filed monitoring data of gully erosion which is needed in gully erosion study, but I cannot find any novel techniques/results/conclusions.

The superiority of field investigation in gully erosion study is that gully development processes is real, which is different to lab experiments based on fill back soil. Therefore, the discussion part should emphasize the different results between field investigation and lab experiments. By the comparison, whether the author found some new conclusions or found that the existing conclusions are unreasonable.

Overall, I suggest a rejection or a major revision.

Detailed Comments

Line 31-34, the example of impact of water erosion need to add reference.

Line 64-66 and 68-69, obtaining of gully morphology was not only used DEM, SFM or Point cloud also could get it.

Line 72-73, the limitations should be more clearly, maybe is accuracy or difficult to deploy.

Line 73-75, the sentence need reference.

Line 128-131, it should be clear which equipment was used to measure the parameter.

Line 146 (i.e. table 1), definition of plan area is needed.

Line 168-170, it is best to show position of the deposition in the figure 2.

Line 176, definition of slope shape is needed.

Line 182, caption of table 2 need to add width variation.

Line 183 (i.e. table 2), “enlargement variation” in Horizontal title revise to “width variation”. The second “width variation” in vertical title should be “depth variation”.

Figures

Figure 3, title of figure 3A and 3B is needed. What meaning of F1, F2 and F3?

Author Response

We deeply appreciate the comments provided and the detailed suggestions to improve the text. We agree with the reviewer and have proceeded accordingly. Please see the attach.  

Author Response File: Author Response.pdf

Reviewer 3 Report

I found the topic of the study very interesting and in line with the scope of the journal. To improve the overall quality of the manuscript, I have some suggestion/comments as below:

The manuscript contains patches of text (lines 19 – 23; 148-153; 162-167; 246-279; 282-287; 292-302) that are almost word-to-word copied from various published documents.

The quality of the figures 1, 2 and 3 may be improved, at least in my pdf they are getting a bit distorted.

Section 2.2 Monitoring morphological changes in the gully and statistical analysis, requires an expert knowledge of the subject. It would be advisable to use a diagram or graph to clarify this.

References: bibliographic citations should be reviewed (format of the year, ...)

English needs to be revised.

Author Response

We deeply appreciate the comments provided and the detailed suggestions to improve the text.

The authors took into consideration the reviewer's comments, in particular an editing of the tables and figures in order to improve readability. A revision of the bibliography was made, and the discussion was improved, aiming at a better interpretation of the results. Finally, a revision of the English was made.

Round 2

Reviewer 1 Report

I am very confused the gully morphological parameters in Table 1 2015? or 2019?

Local factors could be confirm? Just monitoring a gully for 4 years? 38 sampling number for Table 2 and 3? from the only one gully? So, these samples collected from the topsoil? Or long a soil profile? Material and Method NEEDs a major revision and necessary information must be added.

The differences in width, depth, WDR, SS, coverage, slope resistance, etc...in the targeted gully is great? After all, the gully was only 116 m length. So, the spatial heterogeneity of these factors is large? I doubt the credibility of the result mainly due to the limited gully sample number.

Author Response

The authors clearly understand the doubts raised, which we believe will contribute to the improvement of the work.

The morphological parameters in table 2 refer to 2019. It is now noted in the text (see highlighted in the text). The samples taken for analysis of the soil penetration resistance and torsional strength were obtained at several points of gully wall, or at least, in the topsoil, at the midpoint and at the base of the gully wall and averaged. This information is now placed in the methodology.

Although the gully is about 116 metres long and the analysis period relatively short, very significant modifications were detected in the gully channel, particularly in the final section of the channel. The steep slope and the friable characteristics of the substrate through which the gully evolved seem to contribute to this variation. On the other hand, the widening is largely justified by the collapse of material from the gully walls, especially where the soil has less resistance, and where the slope is higher.  On the other hand, forest fires, recurrent over the years, may have increased this process (see highlighted in the text). There are several gullies in the vicinity with similar characteristics and with a very rapid evolution that somehow seems to be justified in part by what the study presented suggests.

Author Response File: Author Response.docx

Reviewer 2 Report

Every comment I made has been corrected and explained by the author. I think the article has met the requirements for publication, and it is recommended to accept it.

Author Response

The authors would like to thank you once again for the comments and suggestions made, which have contributed in a very significant way to the improvement of the article now presented.

Reviewer 3 Report

The revised version is well-written, scientifically conducted and the conclusions were comprehensively supported by the data, therefore, the revised version can be accept in present form.

Author Response

The authors would like to thank you once again for the comments and suggestions made, which have contributed in a very significant way to the improvement of the article now presented.

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.