Investigating Groundwater Condition and Seawater Intrusion Status in Coastal Aquifer Systems of Eastern India
Round 1
Reviewer 1 Report
I think this kind of investigation on groundwater conditions in an area, collection and analysis of the data relevant to the groundwater system, is important as a basis for future research and appropriate management of the precious coastal water resources, as the authors state.
Although Introduction part is well written, there seem to be two major and many minor defects in the manuscript and revisions or modifications are recommended, as follows.
1. Descriptions of the materials and methods (3.) are insufficient, especially of the materials (3.1). This makes difficulties in understanding details of the procedures used in this study, and in evaluating the significance of the results. It is essential to describe which time interval the collected and analyzed time series data have. Specifically, the collected rainfall, groundwater-level, and groundwater-quality data are which of annual, monthly, daily, or hourly sampled data? It also needs to describe in 3.2 which span of the time series data were subjected to each of the statistical tests at one time. Without this information, the readers will not be able to understand the significance of the results. This only is the critical defect of this manuscript, I think, but it will relate to revision of the overall manuscript.
2. Descriptions of the results in 4.3 and 4.4 are lengthy. Especially for 4.4, the results are presented only in the text. Because of this and the illegibility of Figure 1 as mentioned later, the readers will not be able to follow the description in 4.4. The descriptions in L283-289 and L309-317 in 4.3 may be written in a table, if to specify all the ranges of GWL is essential. It is recommended that the results described in 4.4 be presented in time series graphs (like in Figures 2 and 3), distribution maps, and/or table(s).
Because of the above two major defects, I could not fully inspect and evaluate the manuscript. The following minor comments may be meaningless if the authors revise the manuscript corresponding to the above two comments and then polish the manuscript. I do not require one-to-one response to the minor comments below.
3. L112-113: Please check the signs for degree, minute, and second. The used degree sign is unfamiliar to me. Minute should be represented by prime symbol, and second should be by double prime symbol, I think.
4. Figure 1: Almost all the texts in the figure are unreadable and the boundaries of the colored regions are blurred. Please increase the resolution and/or retype the texts and trace the boundaries with line drawings.
5. L117: Please use superscript "2" in "km2."
6. L126: What is the antecedent of the relative pronoun "which"? If the antecedent is "The study area", it may be better to write "... age, and is overlain by ..." If the antecedent is "unconsolidated alluvial sediments", "which is overlain ..." should be replaced with "which are overlain ...".
7. L153: It is better to use the authentic minus sign to represent minus in "n-2," not using hyphen-minus.
8. Eq (2): "j" in the subscript of the first summation may be "i". Please check the entire equation.
9. Eq (4) and L170: Please do not use the same character "m" for representing a different variable than in Eq (1). Please replace "m" in Eq (1) or Eq (4) with another character.
10. L170: Please explain what are "tied groups" a little more.
11. L182-184: To understand the way described here to interpret the result of the innovative trend test, specifically, to interpret that plotted points above and below the 1:1 line indicate increasing and decreasing trend, respectively, it may be necessary to explain which of the values of the two sub-series are plotted on which of the horizontal and vertical axis.
12. L186: The formula to calculate the slope value "s" should be given near here. Explanation in L194-195 (Equation (8)) is better to be moved to nearby the current L186.
13. L193(Eq (7)): Please explain σ, y1, y2, and the overlines on y in the right-hand side.
14. L205-206: Please make it clear who estimates the utilizable recharge. The authors estimate it in this study or some governmental organizations do it? If the latter is the fact, this description may not be necessary here.
15. L216-217: I could not understand this one sentence. Please explain "suitable classes."
16. L219: "Discussions" in plural form is usually not used.
17. L223-226 and L229-230: I could not see from Tables 1 and 2 the described consequences of the trend analysis, because the three tests sometimes appear to have given different results. It should be necessary to explain in 3.2 how the authors finally judged the presence or absence of a trend when the three tests yielded different results.
18. L264-265/L268-269: Either of the two sentences seems not necessary.
19. L272: Is the average of the groundwater elevations over observation points or over time? If it is an average over observation points, one average value is calculated from what range of the observation points? In any case, it is necessary to also describe one average value is calculated from time series data of which sampling interval within what range of the observation duration? This is related to my first comment.
20. L272: Abbreviation "GWE" is not necessary, because it is not used elsewhere in this manuscript.
21. L283-289 and L309-316: It is better to replace the lengthy descriptions here with lists in a table or tables.
22. L292-295: The description here appears dogmatic, because premise or logic of the described interpretation on the cause of the GWL decline by the authors is not explained in detail. If the authors cannot add such detailed explanation, it is better to start the sentence in L292-293 with something like "This should be because ... ". It is better to also replace "... resulted in the decline ..." in L295 with something like "... certainly led to the decline ...".
23. Figures 2 and 3: It is ambiguous which year each of the bar charts of the annual rainfall is for.
24. L439: The used data appears to be of years 2011, 2012, 2013, and 2014 according to the description here. However, in L135-136, the collected groundwater-quality data appears to be of 2005 to 2012. Data of 2013 and 2014 were collected from where?
25. L437-440: It is recommended to show the spatial distributions of the groundwater qualities in distribution maps.
26. L445: It is better to explain who defined the permissible limits. The authors defined the limits or some governmental organizations did? If the limits are based on some authorized criteria, please cite it.
27. L455-458 and L460-462: The descriptions here appear dogmatic. If evidence or other previous studies that proved or at least suggested the intrusion of saline water into the rivers, it should be presented or cited.
28. L463: I could not distinguish which part of the description in the preceding part of the text is "discussion." If the authors improve the explanation of the reason why the authors could deduce the currently written cause of the saline water intrusion, with addition of the basis (evidences or citations), this may be resolved.
29. L475-481: This part may not be necessary in Conclusion and it may be better to incorporate into Introduction chapter, of course with shrinkage of the description if the incorporation makes redundancy.
30. L489-500: This part appears redundant. Please summarize the description, or it may not be necessary in Conclusion chapter, because almost the same description is given in the previous chapter.
31. L500-501: Please explain in a little more detail how this study can be useful for other coastal regions of India and of the world. The results of this study can, or the methods of this study can? In addition, this study can be useful for what activity the readers may do (e.g., management of the groundwater resources, etc.)?
Author Response
Please refer to the attached file. Thank you!
Author Response File: 
Author Response.doc
Reviewer 2 Report
My comments and suggestions are in the document attached
Comments for author File: 
Comments.pdf
Author Response
Please refer to the attached file. Thank you!
Author Response File: Author Response.doc
Reviewer 3 Report
This study investigated the spatio-temporal characteristics and change in trend of groundwater levels in a leaky confined and a confined aquifer system before and after monsoon. The paper is generally well written and structured, but there is a lack of quantitative description in the abstract and in the introduction (e.g., lines 78-88). Only results and interpretations were presented in section 4 (Results and discussions), but NO discussion was found, please add some in-depth discussions and citations as well.
Author Response
Please refer to the attached file. Thank you!
Author Response File: Author Response.doc
Reviewer 4 Report
The introduction is quite well done, but it introduces a number of topics that are not covered in the article, e.g. numerical modelling, geochemical and isotopic analysis.
chapter 2 is very minimal and should be heavily revised and integrated. Figure 1 is illegible.
Materials and methods are sufficiently explained.
The analysis of the trends is interesting, but very superficial. Only the trends of the piezometric levels are verified, but they are not contextualized in the area under study, other possible variables in play are not statistically analysed, e.g. precipitations, withdrawel. The geological and dynamic issue of the processes of the aquifer system is completely missing. Figures 2 and 3 are illegible.
Chapter 4.4 is completely on trust, nothing is presented in detail.
The conclusions reported are not at all supported by the type of analysis done.
I believe that the article is not sufficient for a scientific publication, the approach is interesting, but must be contextualised and integrated into a broader context.
Author Response
Please refer to the attached file. Thank you!
Author Response File: Author Response.doc
Reviewer 5 Report
Halder et al. performed an spatio-temporal analyses of pre-monsoon and post-monsoon groundwater levels of two aquifer systems, evaluating the status of seawater intrusion in the aquifers using available groundwater-quality data.
The title is relevant and the abstract is concise and written in a clear manner.
The introduction is properly cited and explains the importance of the work and key points.
The Overview of Study Area could use a more clearer image, and description.
Line 135-137 should be further detailed.
The equations used although in a simplistic manner seem concise and relevant
The results and discussions chapter should be re-written in a more easy to comprehend manner, avoid over-complication and keep things simple.
Overall a well done work, the style in which some chapters have been written should be simplified. I propose a minor revision
Author Response
Please refer to the attached file. Thank you!
Author Response File: Author Response.doc
Round 2
Reviewer 4 Report
The statistical treatment part is well done and well explained, but by itself it is not sufficient for a study on water sustainability and management in a coastal environment. The map part continues to be very superficial.
I still think that the article does not have the research quality for a publication in Water. The authors in my opinion should aim for a lesser-rated journal.
