An Integrated Principal Component and Hierarchical Cluster Analysis Approach for Groundwater Quality Assessment in Jazan, Saudi Arabia

Round 1

Reviewer 1 Report

 

Review report for the manuscript “water-2281729”

I have gone through the manuscript entitled “An integrated principal component and hierarchical cluster analysis approach for groundwater quality assessment in Jazan, Saudi Arabia”. The topic is relevant to the journal aims and scope. However, the manuscript is not well written. Further, the objective and novelty of this work is not clear. In the abstract, the following lines are mentioned. “A total of 180 groundwater samples were collected and tested for important hydro-chemical parameters used to determine its adaptability for irrigation and drinking”. But, there is no information about drinking water quality assessment in the manuscript. Hence, the current format of this manuscript is not suitable for publication. Need Major revision.

Detailed comments

1.     Abstract – Most of the sentence – incomplete. Check the objective. You have mentioned drinking water quality assessment. But, in the result and discussion, nothing. PCA 1-interpretation is wrong. What is the source of chloride and why it is highly loaded. You have mentioned mineral weathering. What is the mineral source for chloride.

2.     Abstract - Gibbs interpretation is wrong. Gibbs plots show only evaporation followed by mineral weathering. Clarify.

3.     Introduction – need major revision. You have discussed only Saudi Arabia and Jizan. Lot of discussion related to Jizan only. It should be moved to the study area.

4.     Objectives are not clear. Revise it.

5.     Earlier studies in Jizan are not mentioned in the introduction.

6.     Examples

Masoud MHZ, Rajmohan N, Basahi JM, Schneider, M, Niazi BAM, Alqarawy A (2022).  Integrated hydrogeochemical groundwater flow path modelling in an arid environment. Water (MDPI) Water, 14(23): 3823

 Masoud MHZ, Rajmohan N, Basahi JM, Niazi BAM (2022). Application of water quality indices and health risk models in the arid coastal aquifer, Southern Saudi Arabia. Environmental Science and Pollution Research, 29(46):70493–70507. 

 Basahi JM, Masoud MHZ, Rajmohan N (2018). Impact of flash flood recharge on groundwater quality and suitability in the Wadi Baysh Basin, Western Saudi Arabia – Integrated approach. Environmental Earth Sciences, 77:395.

 Basahi JM, Masoud MHZ, Rajmohan N (2018). Effect of flash flood on trace metal pollution in the groundwater - Wadi Baysh Basin, Western Saudi Arabia. Journal of African Earth Sciences, 147:338-351.

 

7.     Line 48. 450C???

8.     Methodology – you have mentioned data analysis (161-168) followed by water analysis. Rearrange it,

9.     You have mentioned drinking water quality assessment in abstract. No information here.

10.  Check the lines 175 and 176. Chloride (Cl-) and bicarbonate were investigated using volumetric methods (HCO3- ). Sulfate was determined using colorimetric and turbidimetric methods (SO4 2- ).

11.     IC used for NO3 but not for Cl and SO4, why?

12.   Line 190-191. Wrong statement. “Furthermore, the presence of alkali earth elements (Ca + Mg) in excess of HCO3 - in some groundwater of the study area strongly suggests that they are provided by mechanisms of silicate weathering.”. If the excess Ca and Mg over HCO3 means, it is not due to silicate weathering. It is called Reverse Ion exchange.

13.   What is the anion coming from silicate weathering to balance the Ca and Mg in water? explain. The only anion coming from silicate and carbonate weathering is HCO3. Similar misinterpretation is identified in several publications.

14.   Please refer the following book.

Aquatic Chemistry by Stumm and Margon. https://www.amazon.com/Aquatic-Chemistry-Chemical-Equilibria-Natural/dp/0471511854

 

15.     Please correct the remaining part in results and discussion based on the above information

16.   The following citation may be useful for you.

17.  Rajmohan N, Elango L (2004). Identification and evolution of the hydrogeochemical process in the groundwater environment in a part of Palar and Cheyyar river basins, South India. Environmental Geology, 46(1): 47-61.

 

18.    Figure 2. You have plotted pH also. Remove the unit (mg/l) in y-axis and mention in the title.

19.   Section – 4.2. change the title – Irrigation water quality assessment

20.   Line 199-what is NA? clarify

21.   Rewrite. No excellent classes (<1%). According to Table 3, the observed EC values for groundwater samples from the study area range from good to excellent for irrigation, with 10% being excellent to good, 42.78% being permissible, and 47% being improper for irrigation (Table 3 and 203 Fig. 3a)

22.   Figure 3 – Increase the legends Font size.

23.   Line 235 – chloro-alkaline unbalance in the aquifer???. Rewrite it. Reverse ion exchange.

24.   Line 242 – Rewrite as reverse ion exchange. “indirect base-exchange reaction”

25.   Section -4.3.3. Please remove the NO3 in the anion plot. It will modify the original processes. Cl/HCO3 ratio should be used. Read the original publication Gibbs 1970.

26.  Rewrite the equations. Redraw the Gibbs plots.

27.  Wrong interpretation. Gibbs plots show that evaporation is the predominant processes followed by the rock-water interaction. No rainfall input.

28.   The following statement is wrong. Lines: 274-275. According to the Gibb's diagram, all of the obtained groundwater samples are located in the rock-water interaction, evaporation, and atmospheric precipitation dominance areas.

29.   Line 274-279- rewrite it

30.   Figure 6a and b. wrong interpretation. Figure 6a- Excees Na over HCO3 – is not due to silicate weathering. Earlier I have mentioned. What is the anion coming from silicate weathering to balance the Na ? explain.

31.   Figure 6b. Excess Ca and Mg. you have mentioned carbonate weathering. Please explain the what is anion coming from carbonate weathering to balance the Ca and Mg?.  

32.   Excess Ca and Mg over HCO3 and SO4 is mainly due to reverse ion exchange only.

33.    Line 282-291 – wrong interpretation. Rewrite it.

34.   Table 5. No need. Remove it.

35.   Please check the factor analysis. Factor 2 and 3 are very strange. If the eigenvalue is greater than one, the variables should be loaded with higher values (> 0.5). here, less than 0.5. please check the FA.

36.   Factor 1. Change the interpretation – it is not due to mineral weathering alone. High loading of Cl indicates the role of evaporation. Hence, it indicates multiple processes.

37.   Conclusion – Again wrong interpretation for gibbs plots. “Gibb’s diagram shows that lithology significantly influences how well groundwater is treated overall, where all of the collected groundwater samples fall into the rock–water interaction, evaporation and atmospheric precipitation dominance fields.

38.   Evaporation>>>>rock-water interaction. Rewrite the conclusions

 

Comments for author File: Comments.pdf

Author Response

Response to Reviewer 01

 Comments of the reviewers are in black, answers are in blue. All changes are made in the manuscript using track-changes.

• General comment: Extensive editing of English language and style required

Response: Thank you so much for this comment. The English language and style have been checked and improved throughout the manuscript. See the revised version of the manuscript.

Detailed comments

1. Abstract – Most of the sentence – incomplete. Check the objective. You have mentioned drinking water quality assessment. But, in the result and discussion, nothing. PCA 1-interpretation is wrong. What is the source of chloride and why it is highly loaded? You have mentioned mineral weathering. What is the mineral source for chloride?

Response: Thank you so much for your valuable comments. The abstract has been modified according to your valuable comments. 

2. Abstract - Gibbs interpretation is wrong. Gibbs plots show only evaporation followed by mineral weathering. Clarify.

Response: It has been corrected in the abstract. This sentence has been added to the abstract “The Gibb’s diagram reflects that evaporation, seawater interaction and water-rock interaction are the foremost process impacting groundwater quality besides of other regional environmental variables.”

3. Introduction – need major revision. You have discussed only Saudi Arabia and Jizan. Lot of discussion related to Jizan only. It should be moved to the study area.

Response: Thank you so much for this comment. The introduction section has been revised. Please see the revised version of the manuscript.

4. Objectives are not clear. Revise it.

Response: Thank you so much for this comment. The objectives have been modified in the revised version of the manuscript, as “The objectives of this research are to investigate the hydro-geochemistry of groundwater in Jazan coastal aquifer; identify the main processes influencing ion enrichment of the groundwater, and finally, the suitability of groundwater for irrigation purposes was evaluated. These could be achieved using physicochemical parameters, different water quality indices, multiple graphical approaches (GIS), and multivariate statistical analysis.”

5. Earlier studies in Jizan are not mentioned in the introduction.

Examples

Masoud MHZ, Rajmohan N, Basahi JM, Schneider, M, Niazi BAM, Alqarawy A (2022).  Integrated hydrogeochemical groundwater flow path modelling in an arid environment. Water (MDPI) Water, 14(23): 3823

 Masoud MHZ, Rajmohan N, Basahi JM, Niazi BAM (2022). Application of water quality indices and health risk models in the arid coastal aquifer, Southern Saudi Arabia. Environmental Science and Pollution Research, 29(46):70493–70507. 

 Basahi JM, Masoud MHZ, Rajmohan N (2018). Impact of flash flood recharge on groundwater quality and suitability in the Wadi Baysh Basin, Western Saudi Arabia – Integrated approach. Environmental Earth Sciences, 77:395.

 Basahi JM, Masoud MHZ, Rajmohan N (2018). Effect of flash flood on trace metal pollution in the groundwater - Wadi Baysh Basin, Western Saudi Arabia. Journal of African Earth Sciences, 147:338-351.

 Response: Thank you so much for your suggestions for these important references. Those references have been added and discussed in the introduction section (using track-changes).

6. Line 48. 450C???

Response: It has been corrected (45 ⁰C)

7. Methodology – you have mentioned data analysis (161-168) followed by water analysis. Rearrange it,

Response: Thank you so much for this comment. The methodology section has been modified.

8. You have mentioned drinking water quality assessment in abstract. No information here.

Response: Thank you so much for this comment. The paper focuses on assessment of water quality for irrigation purposes. Therefore, “drinking” has been deleted from the abstract.

9. Check the lines 175 and 176. Chloride (Cl-) and bicarbonate were investigated using volumetric methods (HCO3- ).Sulfate was determined using colorimetric and turbidimetric methods (SO4 2- ).

Response: Thank you so much for this comment. It has been corrected in section (2.1 Sampling and analysis).

 

10. IC used for NO₃ but not for Cl and SO₄, why?

Response: Thank you so much for this valuable comment. As you know, there are many analytical methods can be used for determinations of NO₃, Cl, and SO₄. The Cl and SO₄  can be determined using IC as well, but in our work the Cl was investigated using volumetric methods and SO₄^2- was determined using turbidimetric method.

11. Line 190-191. Wrong statement. “Furthermore, the presence of alkali earth elements (Ca + Mg) in excess of HCO3 - in some groundwater of the study area strongly suggests that they are provided by mechanisms of silicate weathering.” If the excess Ca and Mg over HCO3 means, it is not due to silicate weathering. It is called Reverse Ion exchange.

Response: Thank you so much for your valuable comment. You are right. The statement has been modified in the revised version of the manuscript.

12. What is the anion coming from silicate weathering to balance the Ca and Mg in water? explain. The only anion coming from silicate and carbonate weathering is HCO3. Similar misinterpretation is identified in several publications.

Response: Thank you so much for your valuable comment. HCO₃^- is released from silicate and carbonate weathering to balance the Ca²⁺ + Mg²⁺ in the groundwater.

13. Please refer the following book.

Aquatic Chemistry by Stumm and Margon. https://www.amazon.com/Aquatic-Chemistry-Chemical-Equilibria-Natural/dp/0471511854

Response:  Thank you so much for suggestion this book. In fact, we couldn't find the book on the internet (It is not available as open access to read and cite it). Therefore, we did not include it in the manuscript.

14. Please correct the remaining part in results and discussion based on the above information

Response: Thank you so much for this comment. The results and discussion sections have been corrected according to your suggestions.

15. The following citation may be useful for you.

Rajmohan N, Elango L (2004). Identification and evolution of the hydrogeochemical process in the groundwater environment in a part of Palar and Cheyyar river basins, South India. Environmental Geology, 46(1): 47-61.

 Response: Thank you for this suggestion. This reference has been added in Lines 390-391 and as follows: Where, weathering of silicate minerals regulates the concentration of major ions such as Na+, Ca2+, Mg2+, and K+ in the groundwater (Rajmohan and Elango 2004).

16. Figure 2. You have plotted pH also. Remove the unit (mg/l) in y-axis and mention in the title.

Response: Thank you so much for this comment. Figure 2 has been modified according to your suggestion.

 

17. Section – 4.2. change the title – Irrigation water quality assessment

Response: It has been changed.

18. Line 199-what is NA? clarify

Response:  It is Na %. It has been corrected in the revised version of the manuscript.

19. No excellent classes (<1%). According to Table 3, the observed EC values for groundwater samples from the study area range from good to excellent for irrigation, with 10% being excellent to good, 42.78% being permissible, and 47% being improper for irrigation (Table 3 and 203 Fig. 3a)

Response: Thank you so much for this comment and correction. The statement has been revised.

20. Figure 3 – Increase the legends Font size.

Response: Thank you so much for this valuable suggestion. All of the maps in Fig. 3 have been repotted with the legends' font size increased.

21. Line 235 – chloro-alkaline unbalance in the aquifer???. Rewrite it. Reverse ion exchange.

Response: Thank you so much for this comment. It has been considered in the revised version of the MS.

 

22. Line 242 – Rewrite as reverse ion exchange. “indirect base-exchange reaction”

Response: Thank you so much for this comment. It has been considered in the revised version of the MS.

23. Section -4.3.3. Please remove the NO3 in the anion plot. It will modify the original processes. Cl/HCO3 ratio should be used. Read the original publication Gibbs 1970.

Response: Thank you so much for your valuable comment. Section 4.3.3 and Gibbs plot (Figure 6) have been modified according to your valuable suggestions.

24. Rewrite the equations. Redraw the Gibbs plots.

Response: The Gibbs equations have been modified.

25. Wrong interpretation. Gibbs plots show that evaporation is the predominant processes followed by the rock-water interaction. No rainfall input.

Response: Thank you so much for your valuable comments. The discussion/ interpretation of Gibbs plots have been revised.

26. The following statement is wrong. Lines: 274-275. According to the Gibb's diagram, all of the obtained groundwater samples are located in the rock-water interaction, evaporation, and atmospheric precipitation dominance areas.

Response: It has been corrected.

27. Line 274-279- rewrite it

Response: This part has been revised in the updated version of the manuscript.

28. Figure 6a and b. wrong interpretation. Figure 6a- Excees Na over HCO3 – is not due to silicate weathering. Earlier I have mentioned. What is the anion coming from silicate weathering to balance the Na ? explain.

Response: Thank you so much for your valuable comment. HCO₃^- is released from silicate and carbonate weathering to balance the Ca²⁺ + Mg²⁺ in the groundwater. While, Na⁺ released from silicate weathering and ion exchange processes. This has been considered in the revised version of the manuscript.

29. Figure 6b. Excess Ca and Mg. you have mentioned carbonate weathering. Please explain the what is anion coming from carbonate weathering to balance the Ca and Mg?  

Response: HCO₃^- is released from silicate and carbonate weathering to balance the Ca²⁺ + Mg²⁺ in the groundwater. It has been corrected in the revised version of the manuscript.

30. Excess Ca and Mg over HCO3 and SO4 is mainly due to reverse ion exchange only.

Response: It has been corrected in the revised version of the manuscript

31. Line 282-291 – wrong interpretation. Rewrite it.

Response: It has been revised in the updated version of the manuscript.

32. Table No need. Remove it.

Response: Table 5 has been removed.

35. Please check the factor analysis. Factor 2 and 3 are very strange. If the eigenvalue is greater than one, the variables should be loaded with higher values (> 0.5). here, less than 0.5. please check the FA.

Response: Thank you for this valuable comment. We double-checked the factor analysis results, and they are correct.

36. Factor 1. Change the interpretation – it is not due to mineral weathering alone. High loading of Cl indicates the role of evaporation. Hence, it indicates multiple processes.

 

Response: Thank you for this valuable comment. It has been corrected in Lines 432 – 435 in the revised version of the MS

 

37. Conclusion – Again wrong interpretation for gibbs plots. “Gibb’s diagram shows that lithology significantly influences how well groundwater is treated overall, where all of the collected groundwater samples fall into the rock–water interaction, evaporation and atmospheric precipitation dominance fields.

Response: The conclusion section has been revised and the interpretation for Gibbs plots has been corrected.

38. Evaporation>>>>rock-water interaction. Rewrite the conclusions

Response: Thank you for this valuable suggestion. The conclusions section has been modified.

 

Finally, the authors would like to express their gratitude for all of your insightful comments, which assisted us in improving the manuscript's quality.

Author Response File: Author Response.pdf

Reviewer 2 Report

In my opinion this paper is an interesting study and authors have determined groundwater features and its suitability for irrigation purposes using physicochemical parameters, different water quality indices (WQIs), multiple graphical approaches, GIS, and multivariate statistical analysis, such as cluster analysis (CA), factor analysis (FA), principal components analysis (PCA), discriminant analysis (DA).

Dear authors, thank you for submitting the manuscript to the journal of Water. Its topic is very interesting. However, the current version of the paper suffers from a number of weaknesses related to the empirical strategy used. I have the following comments/questions for the authors:

Abstract

·         Line 22. "drinking". The assessment of groundwater quality for drinking not found in the manuscript. Please delete the word "drinking" form the abstract section.

·         Lines 22 to 25. Please transfer this sentence after the end of the sentence at Line 38.

·         Lines 34 and 35. Please review the charges of cations and anions in all manuscript and use the numbers to express the charges of ions.

·         The abstract could be more specific. I suggest the authors should organize the abstract as well as main text in four sections, namely: scope, objectives, methods, results, conclusions. Also, abstract section should be completed with the results of the study. The abstract section needs a lot of improvement in scientific writing. There are many sentences which are not properly presented.

·         Add important results of the used water quality indices (WQIs) for assessing groundwater quality in the abstract section.

·         The authors ought to re-write the abstract so that it briefly presents the problem at hand, objectives of the study, methods used to achieve the objectives in logical order. Also, abstract section should be completed with the results of the study.

Introduction

·         The introduction of the manuscript was poorly written. Try to highlight the regional or national significance of this study.

·         In introduction chapter please focus on problem generally, on the basis of examples in the whole World, not your study area.

·         Add some facts and figures of groundwater quality around the globe in your introduction.

·         Add some recent article to make your introduction more attractive and strong. I propose to add this survey method in the overview section of the introduction section, based on the latest literature. Please replace old citations (if it is possible) or add citations of newest literature.

https://doi.org/10.3390/w15040694

https://doi.org/10.3390/w12123300

https://doi.org/10.3390/w15010182

https://doi.org/10.3390/w14030483

·         Line 111. Please modify Sodium into sodium and Bicarbonate into bicarbonate.

·         Line 112. Please modify (HCO₃) into (HCO₃^-), also modify Nitrate (NO3), sulfate (SO₄) into nitrate (NO₃-), sulfate (SO₄^2-).

·          Line 116. "WQI". Please do not use abbreviation in the first time.

·         Line 122. Principal component analysis, cluster analysis. Please change it to (PCA), (CA).

·         Line 123. "Water quality index". Please change it to (WQI). Change the word "With" into "with".

·         Line 125. "IWQI". Please do not use abbreviation in the first time. 

Materials and Methods

Study area (Please transfer this section under Materials and Methods section)

·         Describe all the features of the study area in brief including topography, and hydrogeology?

·         Would you please give more information about the coastal groundwater aquifer in Jazan province (e.g., aquifer characteristics, depths to groundwater, groundwater levels, and total depths)?

Sampling and Analysis (Please add this section)

·         Please start this section with lines 169 to 180.

·         Please give detailed information on water samplers (e.g., accuracy, manufacturer).

·         Sampling locations were selected carefully within Jazan province to have a good representation of the spatial variability of quality indicators across-section of water quality monitoring. What criteria where analyzed to select this locations?

·         Please give detailed information about the instruments used for groundwater measurements in field and laboratory analysis (e.g., model, accuracy, and manufacturer).

·         Please provide detailed detection methods and quality control results?

·         Please support your methods by providing appropriate references or give the guidelines used to analyze the water quality parameters.

·         How did you do quality control (QC) and quality assurance (QA) on the obtained data to validate the conclusions?

Sampling and Analysis (Please add this section)

·         Please start this section with lines 161 to 168.

·         Please support your methods by providing appropriate references or give the guidelines used and equations.

Results and Discussion

·         Line 199. Please change "NA" to "Na %".

·         You should think how transformational the research is likely to be should be made so that the outcome of the work will have an impact on the community/society facing given sustainability related challenges?

·         Write the practical applications of your work in a separate section, before the conclusions and provide your good perspectives.

·         What long-term impacts will it have on environmental protection and the wider public or the field following the completion of the research?

Conclusion (Please change "Conclusions" to "Conclusion")

·         Concise the text in conclusion and add future work in order to recommend your work. Shorten the length of each and every paragraph by adding only relevant and major findings in your study.

Please respond to all of those comments in the revised manuscript by pointing out precisely and concisely on which page and in which line you have incorporated your response one by one.

Comments for author File: Comments.pdf

Author Response

Response to Reviewer 02

 Comments of the reviewers are in black, answers are in blue.

All changes are made in the manuscript using track-changes.

Comments and Suggestions for Authors

In my opinion this paper is an interesting study and authors have determined groundwater features and its suitability for irrigation purposes using physicochemical parameters, different water quality indices (WQIs), multiple graphical approaches, GIS, and multivariate statistical analysis, such as cluster analysis (CA), factor analysis (FA), principal components analysis (PCA), discriminant analysis (DA).

Dear authors, thank you for submitting the manuscript to the journal of Water. Its topic is very interesting. However, the current version of the paper suffers from a number of weaknesses related to the empirical strategy used. I have the following comments/questions for the authors:

Response: Thank you so much for reviewing the manuscript. All of the comments received have been addressed in the revised version of the manuscript (MS). All changes are made in the manuscript using track-changes.

• General comment: Moderate English changes required

Response: Thank you so much for this comment. The English language and style have been checked and improved throughout the manuscript. See the revised version of the manuscript.

 

Abstract

• Line 22. "drinking". The assessment of groundwater quality for drinking not found in the manuscript. Please delete the word "drinking" form the abstract section.

Response: Thank you so much for this comment. “drinking” word has been removed from the abstract in the revised version of the MS. See Line 22.

• Lines 22 to 25. Please transfer this sentence after the end of the sentence at Line 38.

Response: Thank you so much for this comment. It has been considered in the revised version of the manuscript. See lines 44-47.

• Lines 34 and 35. Please review the charges of cations and anions in all manuscript and use the numbers to express the charges of ions.

Response: Thank you so much for this comment. It has been revised throughout the manuscript.

• The abstract could be more specific. I suggest the authors should organize the abstract as well as main text in four sections, namely: scope, objectives, methods, results, conclusions. Also, abstract section should be completed with the results of the study. The abstract section needs a lot of improvement in scientific writing. There are many sentences which are not properly presented.

Response: Thank you so much for this valuable comment. The abstract has been modified according to your suggestion. See the updated abstract in the revised version of the manuscript.

• Add important results of the used water quality indices (WQIs) for assessing groundwater quality in the abstract section.

Response: Thank you so much for your valuable comment. Some important results of the used water quality indices for assessing groundwater quality have been added to the revised version of the abstract. See lines 29-34 in the abstract.

• The authors ought to re-write the abstract so that it briefly presents the problem at hand, objectives of the study, methods used to achieve the objectives in logical order. Also, abstract section should be completed with the results of the study.

Response: The abstract has been modified accordingly. See the updated abstract in the revised version of the manuscript.

 

Introduction

• The introduction of the manuscript was poorly written. Try to highlight the regional or national

Response: Thank you for this comment. We have included and highlighted some recent works as the regional or national. See lines 152-171 in the revised version of the manuscript.

 

• In introduction chapter please focus on problem generally, on the basis of examples in the whole World, not your study area.

Response: Thank you so much for this comment. It has been considered and the introduction section has been revised.

 

• Add some facts and figures of groundwater quality around the globe in your introduction.

Response: Thank you so much. The introduction includes for some facts and figures of the study area

• Add some recent article to make your introduction more attractive and strong. I propose to add this survey method in the overview section of the introduction section, based on the latest literature. Please replace old citations (if it is possible) or add citations of newest literature.

https://doi.org/10.3390/w15040694

https://doi.org/10.3390/w12123300

https://doi.org/10.3390/w15010182

https://doi.org/10.3390/w14030483

Response:

Thank you so much for these suggested references. The suggested references have been incorporated into the manuscript. Refer to references 23, 30, 31, and 35 in the references section.

• Line 111. Please modify Sodium into sodium and Bicarbonate into bicarbonate.

Response: Thank you so much for this comment. It has been corrected. See lines 48-49.

• Line 112. Please modify (HCO₃) into (HCO₃^-), also modify Nitrate (NO3), sulfate (SO₄) into nitrate (NO₃-), sulfate (SO₄^2-).

Response: Thank you so much for this comment. It has been modified throughout the manuscript.

• Line 116. "WQI". Please do not use abbreviation in the first time.

Response: It has been considered in the revised version of the manuscript. See line 154.

• Line 122. Principal component analysis, cluster analysis. Please change it to (PCA), (CA).

Response: It has been considered in the revised version of the manuscript. See lines 160-161.

• Line 123. "Water quality index". Please change it to (WQI). Change the word "With" into "with".

Response: It has been considered in the revised version of the manuscript. See line 162.

• Line 125. "IWQI". Please do not use abbreviation in the first time. 

Response: Thank you so much for this comment. It has been modified to be as “Irrigation water quality index (IWQI)”. See line 164.

 

Materials and Methods

Study area (Please transfer this section under Materials and Methods section)

• Describe all the features of the study area in brief including topography, and hydrogeology?

Response: Thank you so much for your suggestions. The study area section has been moved to the Materials and Methods section, and it has been modified to include information about geologically, aquifer properties, and hydrogeology of the study area. See line 219-231.

• Would you please give more information about the coastal groundwater aquifer in Jazan province (e.g., aquifer characteristics, depths to groundwater, groundwater levels, and total depths)?

Response: Thank you for this valuable comment. It has ben considered. See line 219-231 and Line 249.

 

Sampling and Analysis (Please add this section)

• Please start this section with lines 169 to 180.

Response: Thank you so much for this comment. A new section (Sampling and Analysis) has been added according to your suggestion.  See lines 243-267.

• Please give detailed information on water samplers (e.g., accuracy, manufacturer).

Response: It has been added in the revised version of the manuscript. See lines 263-267.

• Sampling locations were selected carefully within Jazan province to have a good representation of the spatial variability of quality indicators across-section of water quality monitoring. What criteria where analyzed to select this locations?

Response: Thank you so much for your valuable comment. These data were collected from existing private and government wells, and groundwater samples were collected from all available access wells. Our goal was to select groundwater samples that could cover the entire study area.

• Please give detailed information about the instruments used for groundwater measurements in field and laboratory analysis (e.g., model, accuracy, and manufacturer).

Response: We used the following in the field measurements, pH values are determined using the digital pH meter (Model Cole Parmer). EC was determined using the EC meter (Model WPA cm 35). But for the laboratory analysis, we sent all the groundwater samples to the lab.  See lines 255-257.

• Please provide detailed detection methods and quality control results?

Response: Thank you for this comment. To assess the variability of groundwater data resulting from samples collection and laboratory analysis, all samples were collected in duplicate and analysed in replicate. The chemical analysis results were checked for reliability against the anion-cation balance, where the assessment of the quality-control data resulted <5% of the error from the different replicates. These statements have been considered in the revised version of the MS in section 2.2 Sampling and analysis. See lines 263-267.

• Please support your methods by providing appropriate references or give the guidelines used to analyze the water quality parameters.

Response: Thank you for your comment. The samples were preserved, collected, and analyzed in accordance with the protocols established by the American Public Health Association APHA. See lines 253

• How did you do quality control (QC) and quality assurance (QA) on the obtained data to validate the conclusions?

Response: Thank you for this comment. To assess the variability of groundwater data resulting from samples collection and laboratory analysis, all samples were collected in duplicate and analysed in replicate. The assessment of the quality-control data resulted <5% of the error from the different replicates. These statements have been considered in the revised version of the MS in section 2.2 Sampling and analysis. See lines 263-267.

Sampling and Analysis (Please add this section)

Please start this section with lines 161 to 168.

Response: It has been added in the revised version of the manuscript. See lines 243-267.

 

Please support your methods by providing appropriate references or give the guidelines used and equations.

Response: Thank you so much for this comment. It has been considered in the revised version of the manuscript.

 

Results and Discussion

• Line 199. Please change "NA" to "Na %".

Response: Thanks a lot. It has been considered and corrected in the revised version of the manuscript. See line 270.

• You should think how transformational the research is likely to be should be made so that the outcome of the work will have an impact on the community/society facing given sustainability related challenges?

Response: Thank you for your valuable comment. It has been considered in the revised version of the manuscript (in conclusion section), as below:

“According to the findings of the study, sustainable groundwater management in Jazan requires a comprehensive approach that combines traditional water management practices with modern technologies and governance. The current study may be useful in assisting planners and decision-makers in safeguarding our limited groundwater resources for future generations.” see lines 510-514.

 

• Write the practical applications of your work in a separate section, before the conclusions and provide your good perspectives.

Response: Thank you for your comment. The study's findings with incorporating different techniques to assess groundwater quality is beneficial in understanding the factors that control groundwater quality and can assist officials in effectively controlling groundwater quality and also enhancing the water resources in the study area. This cannot be in a separate section, but we have added at the end of the abstract (Lines 50-53)

• What long-term impacts will it have on environmental protection and the wider public or the field following the completion of the research?

Response: Thank you for your comment. The main objectives of the current study are to investigate the hydro-geochemistry of groundwater in Jazan coastal aquifer; identify the main processes influencing ion enrichment of the groundwater, and finally, the suitability of groundwater for irrigation purposes was evaluated. These could be achieved using physicochemical parameters, different water quality indices, multiple graphical approaches (GIS), and multivariate statistical analysis.

In the present study, we did not investigate the long-term effects on environmental protection. However, some long-term scenarios, including monitoring and management, can be implemented to reduce or control the deterioration of groundwater quality in the study area, such as establishing a seawater intrusion monitoring well network, injection wells along the coast as a managed aquifer recharge, and water quality monitoring measures. These statements have been mentioned in the conclusion section (Lines 515-519).

 

Conclusion (Please change "Conclusions" to "Conclusion")

Response: Thanks for this comment. It has been corrected in the revised version of the manuscript. See line 485.

• Concise the text in conclusion and add future work in order to recommend your work. Shorten the length of each and every paragraph by adding only relevant and major findings in your study.

Response: Thank you so much for this valuable comment. The conclusion section has been revised including your suggestion as “It can be concluded that long-term scenarios, such as establishing a seawater intrusion monitoring well network, injection wells along the coast as a managed aquifer recharge, and water quality monitoring measures, can be implemented to reduce or control the deterioration of groundwater quality in the study area. The investigation of the aforementioned management scenarios can be considered future work.” See lines 515-519.

 

• Please respond to all of those comments in the revised manuscript by pointing out precisely and concisely on which page and in which line you have incorporated your response one by one.

 Response: Thank you so much for all of your insightful comments, which helped us to improve the manuscript's quality. All comments have been taken into account, and the manuscript has been revised accordingly. All changes are made in the manuscript using track-changes.

 

 

Finally, the authors would like to express their gratitude for all of your insightful comments, which assisted us in improving the manuscript's quality.

 

Author Response File: Author Response.pdf

Reviewer 3 Report

The paper presents a hydrochemical analysis of the territory of Saudi Arabia in the south-eastern province of Jazan. Given the seriousness of the problem of water stress in desert areas, every action aimed at protecting and improving the water supply of the population is important. The paper provides a comprehensive approach to assessing the quality of groundwater resources using indicators known from other publications for an enhanced of the analytical approach of water quality. On their basis, the results of tests of water from wells were discussed. However, the methodology does not specify the depth of the wells sampled (line 169).  When providing the determination methods, the specification of the measuring equipment (producer, model) (line 175) was omitted.

In the Results and Discussion chapter -line 188, the Authors used the vague statement "Because of the dominance of Na⁺ and Cl^-, the trend was typical of a freshwater system." For which region ? An increased content of these ions rather indicates external pressures (sea, anthropogenic).  

In chapter 4.2. the Authors give the values of indicators and their suitability for irrigation, e.g. EC – 47% improper, SAR almost 92% excellent, PS -83% are injurious to unsatisfactory for irrigation uses.  Which of the indicators determines the suitability for irrigation? Is it enough that one does not meet the criterion and the water is not suitable for irrigation?

The maps in Fig. 3 have wrong markings – a and b are missing.

A large range of values of the marked parameters affects the ambiguous results. In my opinion, the PS, PI and Cl-  vs. Na⁺ and TDS correlation suggest the influence of seawater on the hydrochemical conditions of the studied area, especially its south-eastern part - coast. However, what the Authors suggest in chapter 4.3.3.  -line 277 is absolutely right, but is it for the whole studied area? I believe that the studied area is heterogeneous in terms of hydrochemistry and different factors may determine the composition of groundwater depending on the place of intake (south-eastern and western parts of the area).

line 134 : “To establish effective management of Jazan region... This study aims to provide techniques for enhanced groundwater assessment …” The aim of the work was also adopted "to provide techniques for enhanced groundwater assessment..." (line 135). In view of the results obtained, is the water from the studied area suitable for utility purposes? -any suggestions in the conclusions should be included.  

Author Response

Response to Reviewer 03

 Comments of the reviewers are in black, answers are in blue.

All changes are made in the manuscript using track-changes.

Comments and Suggestions for Authors

The paper presents a hydrochemical analysis of the territory of Saudi Arabia in the south-eastern province of Jazan. Given the seriousness of the problem of water stress in desert areas, every action aimed at protecting and improving the water supply of the population is important. The paper provides a comprehensive approach to assessing the quality of groundwater resources using indicators known from other publications for an enhanced of the analytical approach of water quality. On their basis, the results of tests of water from wells were discussed. However, the methodology does not specify the depth of the wells sampled (line 169).  When providing the determination methods, the specification of the measuring equipment (producer, model) (line 175) was omitted.

Response: Thank you so much for your valuable comments. The depths of the wells sampled ranged from 15 to 97 m above sea level. We used the following in the field measurements, pH values are determined using the digital pH meter (Model Cole Parmer). EC was determined using the EC meter (Model WPA cm 35). But for the laboratory analysis, we sent all the groundwater samples to the lab.  This information has been added into the revised version of the manuscript (track-change).

In the Results and Discussion chapter -line 188, the Authors used the vague statement "Because of the dominance of Na⁺ and Cl^-, the trend was typical of a freshwater system." For which region? An increased content of these ions rather indicates external pressures (sea, anthropogenic).  

Response: Thank you so much for this comment. You are right. It has been deleted from the revised version of the manuscript.

 

In chapter 4.2. The Authors give the values of indicators and their suitability for irrigation, e.g. EC – 47% improper, SAR almost 92% excellent, PS -83% are injurious to unsatisfactory for irrigation uses.  Which of the indicators determines the suitability for irrigation? Is it enough that one does not meet the criterion and the water is not suitable for irrigation?

Response: Thank you so much for this comment. It is not necessary for all indicators to provide a high value for agricultural water suitability. It is possible that one does not meet the criterion and the water is unfit for irrigation (as you said). In this case, however, the water can be used for a specific type of plant.

The maps in Fig. 3 have wrong markings – a and b are missing.

Response:  Marking “a” and “b” have been added

A large range of values of the marked parameters affects the ambiguous results. In my opinion, the PS, PI and Cl-  vs. Na⁺ and TDS correlation suggest the influence of seawater on the hydrochemical conditions of the studied area, especially its south-eastern part - coast. However, what the Authors suggest in chapter 4.3.3.  -line 277 is absolutely right, but is it for the whole studied area? I believe that the studied area is heterogeneous in terms of hydrochemistry and different factors may determine the composition of groundwater depending on the place of intake (south-eastern and western parts of the area).

Response: Thank you so much for this valuable comment and suggestion. You are right. Based on the spatial distribution of the water quality indices (Fig.3), The PS, PI, and Cl- vs. Na+ and TDS correlations indicate that seawater has an impact on the hydrochemical conditions of the studied area, particularly its south-eastern coast. This has been mentioned in section 3.2 in the revised version of the manuscript.

line 134 : “To establish effective management of Jazan region... This study aims to provide techniques for enhanced groundwater assessment …” The aim of the work was also adopted "to provide techniques for enhanced groundwater assessment..." (line 135). In view of the results obtained, is the water from the studied area suitable for utility purposes? -any suggestions in the conclusions should be included.  

Response: Thank you so much for this comment. The objectives of the present study have been revised and modified to be as “The objectives of this research are to investigate the hydro-geochemistry of groundwater in Jazan coastal aquifer; identify the main processes influencing ion enrichment of the groundwater, and finally, the suitability of groundwater for irrigation purposes was evaluated. These could be achieved using physicochemical parameters, different water quality indices, multiple graphical approaches (GIS), and multivariate statistical analysis.” All of the above objectives have been achieved, the results obtained have been discussed, and a conclusion and recommendations have been reached. You can see the updated objectivise at the end of the introduction section.

 

Finally, the authors would like to express their gratitude for all of your insightful comments, which assisted us in improving the manuscript's quality.

 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The manuscript quality is improved. I found small correction in figure 6. Remove carbonate weathering in 6a and add silicate weathering/ion exchange reactions. In the figure 6b, remove silicate weathering because the excess Na over bicarbonate may be due to ion exchange or dissolution of NaCl. Correct it. After performing this correction, the manuscript may be accepted for publication. 

Author Response

Response to Reviewer 01

Comments of the reviewers are in black, answers are in blue.

All changes are made in the manuscript using track-changes.

 

Comments and Suggestions for Authors

In my opinion this paper is an interesting study and authors have determined groundwater features and its suitability for irrigation purposes using physicochemical parameters, different water quality indices (WQIs), multiple graphical approaches, GIS, and multivariate statistical analysis, such as cluster analysis (CA), factor analysis (FA), principal components analysis (PCA), discriminant analysis (DA).

Dear authors, thank you for submitting the manuscript to the journal of Water. I have the following comments for the authors:

Response: Thank you so much for all of your insightful comments, which assisted us in improving the manuscript's quality.

 

Introduction

I propose to add this survey method in the overview section of the introduction section, based on the latest literature. Please add citations of newest literature.

https://doi.org/10.3390/w15061216

Response: The suggested reference has been added (see reference no. 34 in the introduction and reference section)

 

References

Line No. 630. Please write this reference in the correct method (Some authors are missing) https://doi.org/10.3390/w15020289

Response: The reference has been corrected (see reference No. 39 in the reference section)

 

Quality of English Language: English language and style are fine/minor spell check required

Response: Thank you so much for this comment. The English language and style have been checked and improved by a native English speaker. See the revised version of the manuscript.

 

Reviewer 2 Report

In my opinion this paper is an interesting study and authors have determined groundwater features and its suitability for irrigation purposes using physicochemical parameters, different water quality indices (WQIs), multiple graphical approaches, GIS, and multivariate statistical analysis, such as cluster analysis (CA), factor analysis (FA), principal components analysis (PCA), discriminant analysis (DA).

Dear authors, thank you for submitting the manuscript to the journal of Water. I have the following comments for the authors:

Introduction

·         I propose to add this survey method in the overview section of the introduction section, based on the latest literature. Please add citations of newest literature.

https://doi.org/10.3390/w15061216

References

·         Line No. 630. Please write this reference in the correct method (Some authors are missing) https://doi.org/10.3390/w15020289

The article is written correctly, includes a discussion of the research findings, and a good review of the literature. The results are presented in a clearly structured manner. The paper has a logical structure and clearly describes the methodology. The manuscript has been significantly improved and can now be accepted after minor revision.

Comments for author File: Comments.pdf

Author Response

Response to Reviewer 02

 Comments of the reviewers are in black, answers are in blue.

All changes are made in the manuscript using track-changes.

 Comments and Suggestions for Authors

The manuscript quality is improved. I found small correction in figure 6. Remove carbonate weathering in 6a and add silicate weathering/ion exchange reactions. In the figure 6b, remove silicate weathering because the excess Na over bicarbonate may be due to ion exchange or dissolution of NaCl. Correct it. After performing this correction, the manuscript may be accepted for publication. 

Response: Thank you so much for all of your insightful comments, which assisted us in improving the manuscript's quality. Figure 6 (a, b) has been modified. See Figure 6 in the revised version of the manuscript.

Quality of English Language: English language and style are fine/minor spell check required

Response: Thank you so much for this comment. The English language and style have been checked and improved by a native English speaker. See the revised version of the manuscript.