Correlation Analysis Between Groundwater Decline Trend and Human-Induced Factors in Bashang Region

Round 1

Reviewer 1 Report

Dear Authors, 

in my opinion the work is ready for pubblication.

Kind regards

Author Response

Dear professor，

Thank you for your approval of my paper. At same time, I also revised the paper.  If your have any opinion of my paper, please contact me any time.

Thanks again.

Yours sincerely

Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript "Groundwater change and cause analysis in Bashang Region" describes the use of multi-source data to calculate and assess the impact of anthropic factors on vegetation and groundwater. The manuscript is scientifically sound and valid, and the research community will definitely  benefit from its results. The figures are of excellent quality, and improve the manuscript quality. Therefore, the maniuscript can be accepted for publication in Water after some minor improvements (mainly formal) based on the reviewer's comments will be implemented.

1) Please pay more attention to the references when using the form "Author et al. " in the text: the citation should be after "et al.". E.g., L87: "Tapley et al. [28] and Chen et al [29]...."

2) L90: Please define the acronym NCP and use it later in the text.

3) What does BS stands for? Please define the acronym

4) L228-229: A reference should be used after "groundwater level handbook released by... (CIGEM)"

5) L277: There are a couple of typos: Q2ndQ2nd; Q3rdQ3rd

6): Please be consistent with the use of bold and italic in the figures: x-axis is in bold in Fig. 3b

Author Response

Point 1: Please pay more attention to the references when using the form "Author et al. " in the text: the citation should be after "et al.". E.g., L87: "Tapley et al. [28] and Chen et al [29]...."

Response 1:  I revised the reference form in the paper.

Point 2: Please define the acronym NCP and use it later in the text. 

Response 2: NCP means North China Plain. I revised the reference form in the paper.

Point 3: What does BS stands for? Please define the acronym. 

Response 3: BS stands for Bashang. I revised the reference form in the paper.

Point 4: L228-229: A reference should be used after "groundwater level handbook released by... (CIGEM)"

Response 4: I inserted a reference to the groundwater yearbook. 

Point 5:  There are a couple of typos: Q2ndQ2nd; Q3rdQ3rd

Response 5: I deleted duplicate characters. 

Point 6: Please be consistent with the use of bold and italic in the figures: x-axis is in bold in Fig. 3b

Response 6: I redrawed Fig. 3b.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This is a very interesting manuscript that uses satellite data to assess changes in groundwater and its causes; the contribution of a RUE model in order to identify human-induced factors in groundwater changes is plausible. I think that the manuscript has the potential to be published in Water after major revisions.

Were there any hydrogeological considerations to define the study area? It is necessary to define the hydrogeological limits in order to reach a better understanding of the groundwater mechanisms and therefore evaluate the different factors that produce the decline in groundwater levels. A hydrogeological conceptual model is needed.

From my point of view, the procedure to estimate the causes of groundwater decline is well explained, however, if “changes” are going to be evaluated, the quality of groundwater (not only storage) should be included; otherwise it must be stated in the title of the paper.

I think that pumping rate is an additional variable that can help to distinguish between human and natural influence on groundwater, therefore I suggest incorporating it in the analysis.

In Figure 8, the GWSA for regions A and B look the same. Why RUE seasonal increases more for Q3rd of Region C if a similar decline of GWSA occurs at the other two regions?

Some comments and suggestions are included in the attached pdf file.

Comments for author File: Comments.pdf

Author Response

Point 1: Were there any hydrogeological considerations to define the study area? It is necessary to define the hydrogeological limits in order to reach a better understanding of the groundwater mechanisms and therefore evaluate the different factors that produce the decline in groundwater levels. A hydrogeological conceptual model is needed.

Response 1: I inserted a description of hydrogeological conditions in the description section of the study area (L109-L112).

Point 2: From my point of view, the procedure to estimate the causes of groundwater decline is well explained, however, if “changes” are going to be evaluated, the quality of groundwater (not only storage) should be included; otherwise it must be stated in the title of the paper.

Response 2: Thank you for your valuable comments. This paper mainly analyzes the groundwater change trend in Bashang area. Referring to your suggestion, I changed the title to Groundwater change trend and cause analysis in Bashang Region. 

Point 3: I think that pumping rate is an additional variable that can help to distinguish between human and natural influence on groundwater, therefore I suggest incorporating it in the analysis.

Response 3: In the discussion section (4.1) of the paper, the increase and decrease in Table 1 were modified to recharge and discharge. The discharge can be regarded as the influence of human factors on groundwater. Referring to the method in the doi: 10.1111/j.1745-6584.2009.00628.x, recharge-discharge is used to indicate the change of groundwater within one year.

Point 4: In Figure 8, the GWSA for regions A and B look the same. Why RUE seasonal increases more for Q3rd of Region C if a similar decline of GWSA occurs at the other two regions?

Response 4: Region A and Region B are spatially adjacent, and the spatial extent of Region B is small, while the spatial resolution of GRACE data is low. Region B is not suitable to analyze the GWSA variation trend separately. The GWSA of Region A and Region B are the result of their spatial extent combination. Since the planting structure of the Region C is mainly crops, the irrigation demand is greater than the Region A (grasses) and the Region B (forests). Therefore, the RUE has a seasonal increase in the Q3rd of the Region C.

The rest of revision details are included in the attached word file.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

The authors have implemented all the necessary modifications to improve the manuscript's quality, following the reviewer's comments. Therefore, the manuscript is now suitable for publication in Water in the present form.

Author Response

Thanks for your suggestion.

Kind regards

Reviewer 3 Report

Point 1: Were there any hydrogeological considerations to define the study area? It is necessary to define the hydrogeological limits in order to reach a better understanding of the groundwater mechanisms and therefore evaluate the different factors that produce the decline in groundwater levels. A hydrogeological conceptual model is needed.

Response 1: I inserted a description of hydrogeological conditions in the description section of the study area (L109-L112).

REVIEWER: I think that a more complete development of the conceptual model is need. A cross section figure to represent it will be very illustrative.

Point 2: From my point of view, the procedure to estimate the causes of groundwater decline is well explained, however, if “changes” are going to be evaluated, the quality of groundwater (not only storage) should be included; otherwise it must be stated in the title of the paper.

Response 2: Thank you for your valuable comments. This paper mainly analyzes the groundwater change trend in Bashang area. Referring to your suggestion, I changed the title to Groundwater change trend and cause analysis in Bashang Region. 

REVIEWER: My suggestion for the title is ” Groundwater level trend and cause analysis in Bashang Region”.

Point 3: I think that pumping rate is an additional variable that can help to distinguish between human and natural influence on groundwater, therefore I suggest incorporating it in the analysis.

Response 3: In the discussion section (4.1) of the paper, the increase and decrease in Table 1 were modified to recharge and discharge. The discharge can be regarded as the influence of human factors on groundwater. Referring to the method in the doi: 10.1111/j.1745-6584.2009.00628.x, recharge-discharge is used to indicate the change of groundwater within one year.

REVIEWER: Even though the Table 1 was improved, natural and artificial discharge will be useful to evaluate the human impact.

Point 4: In Figure 8, the GWSA for regions A and B look the same. Why RUE seasonal increases more for Q3rd of Region C if a similar decline of GWSA occurs at the other two regions?

Response 4: Region A and Region B are spatially adjacent, and the spatial extent of Region B is small, while the spatial resolution of GRACE data is low. Region B is not suitable to analyze the GWSA variation trend separately. The GWSA of Region A and Region B are the result of their spatial extent combination. Since the planting structure of the Region C is mainly crops, the irrigation demand is greater than the Region A (grasses) and the Region B (forests). Therefore, the RUE has a seasonal increase in the Q3rd of the Region C.

REVIEWER: It is therefore necessary to explain in more detail why a similar groundwater level decline occurs although a different extraction is carried out.

The rest of revision details are included in the attached word file.

Author Response

Thank you for your suggestions again. These suggestions are very helpful for the improvement of the paper.

1.Due to the difficulty in obtaining some hydro-geological data in the study area, we were unable to map the cross section figure of the study area. However, based on existing research, we have added a description of the hydro-geological conditions in the study area.

2.Considering your suggestions for points 1 and 2, we believe that there are still some factors not considered in this paper, and the title of the paper should be more specific. Finally, we revised the subject to Correlation analysis between groundwater decline trend and human-induced factors in Bashang Region. Why do we use the “decline trend” instead of the “level trend”? The in-situ measurement data was used to validate groundwater changes predicted by GRACE and GLDAS. This paper mainly focuses on the groundwater trend estimated by GRACE combined with GLDAS.

3. In the current data set, artificial and natural discharge cannot be directly obtained. We hope to reflect the relationship between artificial discharge and groundwater decline by using indirect human-induced factor evaluation index.

4. We added a description of point 4 in this paper.

Author Response File: Author Response.pdf