Study on the Suitable Ecological Groundwater Depth and the Suitable Well–Canal Combined Irrigation Ratio in the Weigan River Irrigation District

Round 1

Reviewer 1 Report

Very well organized article. GREAT JOB!

Author Response

Thank you for your review and constructive comments. Please refer to the WORD document for detailed feedback.

Author Response File: Author Response.docx

Reviewer 2 Report

Dear Authors,

Title: Study on the Suitable Ecological Groundwater Depth and the Suitable Well–Canal Combined Irrigation Ratio in the Weigan River Irrigation District.

 Summary:

This research aims to analyze the response relationship between vegetation dynamics and groundwater depth based on the NDVI index, and determine the groundwater depth that is conducive to maintaining the ecological stability of the study area (Weigan River irrigation district) using the MODFLOW model. 

This paper covers an important subject and provides comprehensive results and discussion in terms of vegetation dynamics and groundwater depth. I believe it should be accepted with minor revisions at this time. Several minor points should be modified to become much better with a higher impact. I list out some main points below and then the comments for the lines.

General comments:

1-     Introduction: It gives a clear and specific background of the subject and literature. No need for any modification.

2-     Methods: The methodology used in this paper is clear. I just recommend explaining more about the double-ring experiments in the field. Also, determining the permeability coefficient and the zoning procedure must be discussed more. For example, what are the main criteria for dividing the area into 7 zones?

Minor comments:

Line 90: "among which the SAVI index is more suitable for characterizing vegetation cover and subsurface changes at small scales." The SAVI index can be used for small and large scales. Kindly modify it or prove it.

Line 136 + 137:" The average annual rainfall in the irrigation area is about 51.5 mm." That means that the climate is dry and precipitation is scarce. I recommend adding the reference.

Line 156: "(https://www.gscloud.cn/search)" The accessed date must be added.

Line 157: "lowest elevation of 804 m in the study area." This value must be the same as in Figure 1. Modify this to 901 m, or modify the lowest value in Figure 1.

Line 162 + 163: "atmospheric and radiometric corrections." Which types of corrections did you carry out? These corrections are vital, and you must explain more about these corrections.

Line 172: "through double-ring experiments in the field." Did you add the results of these experiments in the manuscript or in the supplementary material?

Line 200: "The data show that the groundwater depth significantly increased in 2012". As I understood, the data availability and this are the main reasons for selecting 2012 as the starting year. Subsequently, I recommend adding a figure describing groundwater depth within the last 20 or 25 years.

Line 208: "a square grid dissection of 500 m×500 m". Why did you use this resolution? You can use a grid with more resolution. Explain that in the manuscript.

Line 209: "which was vertically divided into one". Explain why.

Figure 2: add the year to the caption. Also, Figure 2 must be mentioned in the previous paragraph with its purpose.

Line 215: "(2) Boundary Demarcation". This paragraph is very important in this type of research. I recommend adding a detailed figure for the boundary conditions.

Line 232 – 238: Could you please provide me with the results of the field double-loop experiment

 in the study area?

Figure 3: Why did you divide the study area into 7 areas? What are the differences in the K coefficient within the same area? Add a new table showing each zone's range in K values.

Line 312 + 313: “The average depth of groundwater in the upstream area is greater than that in the middle and downstream areas.”. I recommend adding the average value for upstream, middle, and downstream areas.

Line 390: “What is 5.67926 million mu”. What is the “mu”?

Table 3: I recommend adding a line between the scenarios to make it easier to read.

Sincerely,

Minor editing of English language required

Author Response

Thank you for your review and constructive comments. Please refer to the WORD document for detailed feedback.

Author Response File: Author Response.docx

Reviewer 3 Report

The study is interesting, and the results are valuable. Some comments / revisions can improve the paper.

-        More quantitative results must be included in the abstract.

 - I think it is better to compare your results with similar studies.

-        The interaction between surface and groundwater can be presented with more details. The following examples are useful.

“Modeling irrigation behavior in groundwater systems”

“Impacts of agricultural irrigation on groundwater salinity”

-        Please present more details about the hydraulic parameters of study area. The following examples can be useful for guide.

“The exponential decline in saturated hydraulic conductivity with depth: a novel method for exploring its effect on water flow paths and transit time distribution”

“Depth‐dependent hydraulic conductivity distribution patterns of a streambed”

-        There is no representative picture from the study area.

-        There is limited description about boundary condition. It can be very important in your analysis reliability. Please present more details. The pattern in following examples can give you more guide.

“Simulation of groundwater level in a coastal aquifer”

“Impact of Boundary Conditions Dynamics on Groundwater Budget in the Campania Region (Italy)”

-        Please prepare the research flowchart.

-        Are there similar studies in your study area?

-        It is better to investigate the nonstationary behavior in variables according to their data. Or, consider the previous related studies in your case. The following example(s) can be useful.

“Estimation of non-stationary behavior in annual and seasonal surface freshwater volume discharged into the Gorgan Bay, Iran”

“Identifying non-stationary groundwater level responses to North Atlantic ocean-atmosphere teleconnection patterns using wavelet coherence”

Author Response

Thank you for your review and constructive comments. Please refer to the WORD document for detailed feedback.

Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

It is OK