Assessing the Impact of Climate Change on Groundwater Quality of the Shallow Coastal Aquifer of Eastern Dahomey Basin, Southwestern Nigeria
Round 1
Reviewer 1 Report
The manuscript proposes a comprehensive investigation of the impact of seasonal flooding due to extreme precipitation on the groundwater quality of a shallow coastal aquifer in Nigeria. The manuscript, in my view, is a well-written article identifying a significant gap linking climate change and groundwater quality. The selected title is representative. The abstract is very lengthy; as such, I suggest that the author reduces this section to keep only the most essential elements. The literature review offers a useful overview of current research. Given the complexity involved in the method, the author has produced positive outcomes. The current level of the manuscript is appropriate in my readership; hence, I recommend that it be accepted for publication.
Author Response
Thank you for reviewing this manuscript and providing us with useful insight that will enhance the quality of the paper. We appreciate all your comments and feel by addressing them, the paper has significantly been improved based on the comments, and we are extremely grateful.
These comments have been copied and pasted into this document in black, and the author's response to these comments is presented in red text.
Point 1: The manuscript proposes a comprehensive investigation of the impact of seasonal flooding due to extreme precipitation on the groundwater quality of a shallow coastal aquifer in Nigeria. The manuscript, in my view, is a well-written article identifying a significant gap linking climate change and groundwater quality. The selected title is representative. The abstract is very lengthy; as such, I suggest that the author reduces this section to keep only the most essential elements. The literature review offers a useful overview of current research. Given the complexity involved in the method, the author has produced positive outcomes. The current level of the manuscript is appropriate in my readership; hence, I recommend that it be accepted for publication.
Suggestion: The abstract is very lengthy; as such, I suggest that the author reduces this section to keep only the most essential elements.
Response: The abstract has been rewritten based on your recommendation.
Reviewer 2 Report
The weak points of this work are:
1) the lack of a clear definition of the methodology
2) better organisation of the article
3) English need for significant improvement
4) the novelty is not clearly stated.
I would advice to the authors to describe more appropriately the methods of field and laboratory analysis.
Please make a single paragraph for measurements. Please describe the method for sampling and analysis on basis of official standard methods where possible. Please delete futile information as "tubes lablelled nA and nB" these are not important for the replication of methodology.
Data evaluation and statistical analysis. I would advise the authors to describe more fully the work of data evaluation and analysis. Multiple Linear regression model was used for data evaluation so Please add more information about the used methodology in this paragraph.
Please include paragraphs 2.0 and sub-paragraphs in material and methods.
Please pay attention to the citations in the text that need to be standardised.
Line 299. Please correct "PH". Please read the manuscript and correct other mistakes.
Please organize result and discusssion about sulfate, nitrate, iron and manganese in one paragraph.
Paragraph 4.2 seems to be a premise of paragraph 4.3. I would advise the authors to delete the paragraph and try to harmonise its content in the text.
Paragraph 4.5. Please organize better Table 4.
Author Response
Response to Reviewers Comments 2
Overview Remarks:
Thank you for your time in reviewing this manuscript and providing us with useful insight that will enhance the quality of the paper. We appreciate all your comments and feel by addressing them, the paper has significantly been improved based on the comments, and we are extremely grateful.
The Reviewer's comments have been copied and pasted into this document in black, and the author's response to these comments has added in red.
Point 1: Lack of a clear definition of the methodology.
Response: The methodology in this study was well spelled out under heading 3.0 and the following subheadings;
3.1 Field Physicochemical measurement (Line 188)
3.2 Laboratory analysis (Line 202)
3.3 Data evaluation and statistical analysis (Line 208)
All these were backed with references from previous studies which were carried out in line with standard practice.
Point 2: Better organisation of the article.
Response: We have tried different arrangements for the organisation of this article and found out the current state as the possible best to ensure flow and connectivity.
Point 3: English need for significant improvement
Response: In acknowledgment of your comment on some grammatical errors in this manuscript, it had been well proofread by the English language professional after receiving your comment.
Point 4: The novelty is not clearly stated
Response: The novelty of the is paper is clearly stated in the introduction Using redox-sensitive ions and metals to investigate the impact of flood driven by extreme precipitation resulting from climate change on groundwater quality of shallow coastal aquifer of Eastern Dahomey Basin. This is stated in the manuscript between line109 and 119.
“The objectives were to investigate the impacts of climate change through flooding on groundwater quality of the shallow coastal groundwater of the Eastern Dahomey basin, using seasonal redox biogeochemical process of some selected redox-sensitive ions such as Fe, Mn, NO3, SO4. Understanding the possible impacts of this seasonal flooding on the groundwater quality of the freshwater aquifer is critical to the management of this essential resource”.
Finally, all other comments have been duly implemented as seen in the revised manuscript. I sincerely appreciate your contribution. I am sure it has gone a long way in improving the quality of this paper.
Round 2
Reviewer 2 Report
Line 15. Please correct "SO4 and NO3" as SO4 and NO3
Line 23-24. IDEM
Line 25. IDEM
Line 90. Please write the full name of the term "EDB".
Line 171. Please add the model of instrument used.
Line 133-134. Please correct this sentence. In table 1, authors did not describe stratigraphic description.
Author Response
Authors’ Response to the revised version 2
I sincerely appreciate all the comments of the reviewer. Their comments have greatly improved the quality of this manuscript. Below are the suggestions and their confirmation of implementation.
Comment 1
Line 15. Please correct "SO4 and NO3" as SO4 and NO3
Response 1
These have been corrected on line 15 and other parts of the manuscript where observed.
Comment 2
Line 23-24. IDEM
Response 2
You are right that lines 23, 24 to 25 meant the same thing. Both statistical and graphical method combined and presented to validate the interpretation of the data visually. There is probably disconnection between them as observed which we have addressed in the same line.
Comment 3
Line 25. IDEM
Response 3
Answered in response two (2) above
Comment 4
Line 90. Please write the full name of the term "EDB".
Response 4
Line 90 is the same as line 112 because of the deleted space of the previous abstract still within the text. EDB means “Eastern Dahomey Basin” which has been included in the text in line 112.
Comment 5
Line 171. Please add the model of the instrument used.
Response 5
The model of the instrument “MODEL 99720” has been included in new line 193.
Comment 6
Line 133-134. Please correct this sentence. In table 1, the authors did not describe the stratigraphic description.
Response 6
This correction has been implemented in the new line 155.
I thank the reviewer once again for the suggestions. I hope the above responses are satisfactory.
Author Response File: 
Author Response.docx
