Sustainable Groundwater Potential Zoning with Integrating GIS, Remote Sensing, and AHP Model: A Case from North-Central Bangladesh

Round 1

Reviewer 1 Report

Review of Manuscript: sustainability-1649902 titled as “Sustainable Groundwater Potential Zoning with Coupling GIS, Remote Sensing and AHP Model: A Case from Northeast Bangladesh”.

This manuscript reports the zonation of groundwater potentials in the greater Mymensingh District using the GIS, RS and AHP techniques. The topic is of interest for the readership of Sustainability Journal as the outcomes of the study would enrich the groundwater (availability, drivers of change and management options) related scientific literature and provide insights for the researchers and policy makers. However, several points should be clarified and improved before it can be considered for publication. I listed them below in order of appearance in the manuscript also by specifying their relevance.     

Minor 1: The introduction section misses the logical flow and connectivity of sentences. Several sentences repeat the information. Moreover, a robust justification of this study is missing. An improvement of the introduction section citing state of the art methods of groundwater potential zoning is suggested.

Minor 2: P: 4, L: 7-8 “All images were downloaded at level-1 geotiff format” ----Does the author developed LULC map based on level-1 data? Calculations or estimations derived from level-1 data has several accuracy issues. The author needs to add more explanation on the LULC classification. Which classification method was adopted? What were the classification accuracies?

Minor 3: There is a clear mismatch in the result section. The result section includes lot of information better suited with the methodology section. The author should find a better way to explain the rating assignment procedures in the methodology section. Besides, the result section should present the corresponding results only.  

Minor 4: The results are not supported by existing literature. The discussion section requires more discussion referring existing literature.  

Minor 5: The validation section is poorly explained. Why only 8 wells were selected? It would be clearer, had the author calculate the prediction efficiencies. Can the author present a simple correlation between the well yields and potentials zones (the outcome of this study) corresponding rating (i.e. very low = 1 to very high = 5)?

   Specific comments

1. The title reports the northeast Bangladesh. However, the manuscript reports Mymensingh District in some instances and north central in other places. Consistency is suggested to guide the readers.
2. P: 2, L: 6-7 citation required to support the argument.
3. P: 2, L: 8-15 this section has sudden intrusion of issues and thus misses logical flow and sequence. A revision of these sentences is suggested.
4. P: 2, L: 12-15 literature cited [7] here describes the conditions of Dhaka. The argument made here seems to be irrelevant. This section actually justifies the necessity of the present study. Therefore, a revision is suggested.
5. P: 2, L: 16-19 citation required to support the argument.
6. The manuscript reports both km² (P2) and hectors (P3) units. Consistencies are suggested.
7. P: 3, L: 22-24 citation required to support the argument.
8. Text face and size in Figure 1 (and also for all other figures) are not the same with those of body text. Legend keys are also not representative. The map hardly distinguishes between the “district boundary” and “Mymensingh”. Also true for the “Waterbodies” and “inland waterbodies”. A reproduction of the base map is suggested.
9. P: 4, L: 2-3 what is the temporal resolution of rainfall? Rainfall or precipitation? Need to be consistent throughout the manuscript.
10. P: 4, L: 4-5 suggests that lineament density was estimated from the Landsat 8 imageries. Can the author extend this section explaining the methods of lineament density estimation from the optical sensor derived imageries? Also, date of Landsat image needs to be mentioned appropriately.
11. P: 4, L: 7 does the author intends to report a “30 x 30 m spatial resolution”? Need to be updated.
12. P: 4, L: 13-16 “Various analyses and interpretations” -----what are those analyses and interpretations? Can the author specify?
13. P: 4, L: 18 “properly registered” does the author meant an image co-registration? Had the author actually downloaded images of different times and co-registered, need to be clarified. Reading other sections of the manuscript implies that, the author might have “geo-referenced” the data layers.
14. P: 4, L: 19-22 these are simply repeats. A deletion is suggested
15. Section 2.2 and section 2.3 has repeated information. Its better to present the data and sources in a tabular form in section 2.2.
16. P: 5, L: 5 “30*30pixel resolution” ---------does the author means here a 30 x 30 m spatial resolution? make consistent in reporting.
17. P: 5, L: 7 “recognized as significant”---------what was the basis for deciding the significance?
18. P: 5, L: 16-17 “If you're interested in how the weights of different thematic layers or their individual classes are computed, you may use Saaty's consistency ratio (CR)”--Meaning is not clear. Need further clarification.
19. P: 11, Table 2: Assignment of relative weight to each thematic layers are not very clear from the manuscript. Need more background information so that the readers could follow.

Author Response

Response to Reviewer 1 Comments

Minor Comments:

Point 1: The introduction section misses the logical flow and connectivity of sentences. Several sentences repeat the information. Moreover, a robust justification of this study is missing. An improvement of the introduction section citing state of the art methods of groundwater potential zoning is suggested.

Response 1: The introductory section has now been updated by deleting redundant material, providing rationale, and utilizing relevant sources. A thorough discussion of groundwater in international, national, and regional contexts, as well as the importance of long-term resource management was done. Specific methodological descriptions of groundwater potential zoaning were also provided.

Point 2: P: 4, L: 7-8 “All images were downloaded at level-1 geotiff format” ----Does the author developed LULC map based on level-1 data? Calculations or estimations derived from level-1 data has several accuracy issues. The author needs to add more explanation on the LULC classification. Which classification method was adopted? What were the classification accuracies?

Response 2:

The map of land use and land cover was created using landsat-8 images acquired from the USGS earth resource observation system data center (https://earthexplorer.usgs.gov). We generated a land use land cover map using supervised classification based on band combinations. To assure accuracy, we employed real-time comparison with Google Earth images at all stages of LULC map development.

Point 3: There is a clear mismatch in the result section. The result section includes lot of information better suited with the methodology section. The author should find a better way to explain the rating assignment procedures in the methodology section. Besides, the result section should present the corresponding results only.  

Response 3: Both the methodology and the results section have been revised. We relocated the AHP processes from the results section to the methodology section. We have revised the methodology section to provide detailed approaches for rating assignment.

Point 4: The results are not supported by existing literature. The discussion section requires more discussion referring existing literature.  

Response 4: We have revised all of the uncertainties in the result section. The discussion section has also been updated providing particular explanations of the findings.

Point 5: The validation section is poorly explained. Why only 8 wells were selected? It would be clearer, had the author calculate the prediction efficiencies. Can the author present a simple correlation between the well yields and potentials zones (the outcome of this study) corresponding rating (i.e. very low = 1 to very high = 5)?

 Response 5: The validation section has been rewritten. We also used pearson correlation and regression analysis to improve model validation explanations.

Specific comments

Point 1: The title reports the northeast Bangladesh. However, the manuscript reports Mymensingh District in some instances and north central in other places. Consistency is suggested to guide the readers.

Response 01: We have correceted it.

Point 02: P: 2, L: 6-7 citation required to support the argument.

Response 02: we have includes citations.

Point 03: P: 2, L: 8-15 this section has sudden intrusion of issues and thus misses logical flow and sequence. A revision of these sentences is suggested.

Response 03: This section has been rewritten and updated.

Point 04: P: 2, L: 12-15 literature cited [7] here describes the conditions of Dhaka. The argument made here seems to be irrelevant. This section actually justifies the necessity of the present study. Therefore, a revision is suggested.

Response 04: we have corrected it.

Point 05: P: 2, L: 16-19 citation required to support the argument.

Response 05: We have added adequate citation.

Point 06: The manuscript reports both km² (P2) and hectors (P3) units. Consistencies are suggested.

Response 06: All of the hector values have been converted to km².

Point 07: P: 3, L: 22-24 citation required to support the argument.

Response 07: Appropriate citations have been incorporated.

Point 08: Text face and size in Figure 1 (and also for all other figures) are not the same with those of body text. Legend keys are also not representative. The map hardly distinguishes between the “district boundary” and “Mymensingh”. Also true for the “Waterbodies” and “inland waterbodies”. A reproduction of the base map is suggested.

Response 08: As per your recommendation, we've improved the base map.

Point 09: P: 4, L: 2-3 what is the temporal resolution of rainfall? Rainfall or precipitation? Need to be consistent throughout the manuscript.

Response 09: The rainfall map has now been updated. Throughout the manuscript, we've changed "precipitation" to "rainfall."

Point 10: P: 4, L: 4-5 suggests that lineament density was estimated from the Landsat 8 imageries. Can the author extend this section explaining the methods of lineament density estimation from the optical sensor derived imageries? Also, date of Landsat image needs to be mentioned appropriately.

Response 10: We have included a detailed approach for developing lineament density maps. We also provided a table listing the different types of data, data sources, and output layers.

Point 10: P: 4, L: 7 does the author intends to report a “30 x 30 m spatial resolution”? Need to be updated.

Response 10: we have corrected it.

Point 11: P: 4, L: 13-16 “Various analyses and interpretations” -----what are those analyses and interpretations? Can the author specify?

Response 11: All of the analyses and interpretations have been specified as digitization, conversion, interpolation, classification, reclassification, enhancement, filtering, and other GIS processing.

Point 12: P: 4, L: 18 “properly registered” does the author meant an image co-registration? Had the author actually downloaded images of different times and co-registered, need to be clarified. Reading other sections of the manuscript implies that, the author might have “geo-referenced” the data layers.

Response 12: The data layers was 'geo-referenced.' We've corrected it now.

Point 13: P: 4, L: 19-22 these are simply repeats. A deletion is suggested.

Response 13: We've made the required changes based on your suggestions.

Point 14: Section 2.2 and section 2.3 has repeated information. Its better to present the data and sources in a tabular form in section 2.2.

Response 14: we have corrected it. This section includes a data table that lists the various types of data, data sources, and output layers.

Point 15: P: 5, L: 5 “30*30pixel resolution” ---------does the author means here a 30 x 30 m spatial resolution? make consistent in reporting.

Response 15: We have corrected it.

Point 16: P: 5, L: 7 “recognized as significant”---------what was the basis for deciding the significance?

Response 16: There was a grammatical error in the sentence. We have corrected it in revised manuscript.

Point 17: P: 5, L: 16-17 “If you're interested in how the weights of different thematic layers or their individual classes are computed, you may use Saaty's consistency ratio (CR)”--Meaning is not clear. Need further clarification.

Response 17: There was a grammatical error in the sentence. We have now updated it through giving the complete methodology.

Point 18: P: 11, Table 2: Assignment of relative weight to each thematic layers are not very clear from the manuscript. Need more background information so that the readers could follow.

Response 18: Thank you for your suggestion. We have now added the information in this section

Author Response File: Author Response.docx

Reviewer 2 Report

The paper presents an elementary GIS application that addresses groundwater resource identification and management issues in Bangladesh. the paper is poorly referenced and has minimal originality and scientific merit.  With better English grammar it might serve as a project report but  it is hard to imagine this being of much interest to an international scientific community.  Certain aspects of the paper such as the selection of weights - where there is scope for some original thought - was performed in a very arbitrary fashion with no cited reference to prior studies which might have led to a discussion of various weighting techniques. Figures are good - however they do little beyond identifying the various attributes that are combined to create the groundwater resource potential.  It isn't clear how this paper could be salvaged to meet the scientific requirements of the journal.

Comments for author File: Comments.pdf

Author Response

Response to Reviewer 2 Comments

General Comments:

Point 01: The paper presents an elementary GIS application that addresses groundwater resource identification and management issues in Bangladesh. the paper is poorly referenced and has minimal originality and scientific merit. With better English grammar it might serve as a project report but it is hard to imagine this being of much interest to an international scientific community. Certain aspects of the paper such as the selection of weights - where there is scope for some original thought - was performed in a very arbitrary fashion with no cited reference to prior studies which might have led to a discussion of various weighting techniques. Figures are good - however they do little beyond identifying the various attributes that are combined to create the groundwater resource potential. It isn't clear how this paper could be salvaged to meet the scientific requirements of the journal.

Response 01:

Dear Reviewer,

Thank you for taking the time to make such a thoughtful suggestion. Based on your comments, we've updated the entire manuscript with proper literature  reviews. We made some changes during the review process to ensure that the findings were presented clearly. The third section of the introduction includes a full overview of various approaches used in this study and why the AHP method was utilized in this research. In addition, we proofread the document, focusing on grammatical and English language errors. The discussion section has been meticulously updated with the most recent findings and a detailed discussion. This time, we hope you will find this paper fascinating.

Author Response File: Author Response.pdf

Reviewer 3 Report

General Comments:

The research article is designed to study the “Sustainable Groundwater Potential Zoning with Coupling GIS, Remote Sensing and AHP Model: A Case from Northeast Bangladesh”. This study analyzed hydrologic and geographic attributes of the study area Mymensingh district and identified eight major factors influencing groundwater recharge potential, viz. geomorphology, land use/land cover, drainage density, lineament density, soil type, slope, elevation, and annual rainfall.

The article has some Grammar and English language mistakes therefore, I would recommend proofreading the article from an English native speaker.

My serious concern is about the discussion section of the article, which needs improvements and more discussion with the latest literature.

The discrepancies of the article are mentioned below to improve its quality.

Revisions:

The authors must write the problem statement of this particular study and also explain the objective of the article in the abstract.

The final map showed that 11.51% (504.09 km2), 22.74% (995.58 km2), 33.5% (1466.46 km2), 26.88% (1176.84 km2), and 5.37% (235.17 km2) of the study area are for very high, high, moderate, low, and very low groundwater potential zones, respectively. The author must give some suitable zone names to each value for more clear understating .i.e., zone-1 is very high and zone-5 is very low groundwater potential zones. Also mentioned those zones throughout the manuscript.

Also, add the “well yield” word in keywords.

Introduction section, 2^nd paragraph. You have mentioned that,
The groundwater level was found to be depleted over the past decades in this district [8]. Kindly mention the duration i.e., 2000-2020 and mention the water depletion depth 60-80 feet, etc. according to your study area data.

Add more literature review data related to the use of advanced technologies, such as remote sensing and geographic information systems (GIS), for groundwater management to support your study.

The Analytical Hierarchy Process (AHP) method has been adopted in many studies due to its superiority compared to other methods [21]. Kindly mention the good results (3-4) of the other study results to support the validity of this AHP method.

Clearly mention the objective and novelty statement of the study in the last paragraph of the introduction section.

Material and Methods

You have mentioned that “as shown in Figure 2.1.”. Kindly correct the figure number.

2.1. Description of the Study Area, in which you must mention the information of the number of households in the study area, number of water pumps, number of tube wells, and water are their discharge rate per annum according to the daily consumption of the study area population. Therefore, also mention the increase of the tube wells in recent time and how many wells get dry due to lowering of the groundwater table.

2.2. Description of Data, in which you have collected the data from different websites (BWDB, FAO and SGB and Earth Data Site of NASA) than you should mention the links of the sites therefore other could get easily access to those data site.

You have mentioned that, “30*30m spatial resolution”. Kindly use the correct mathematical signs.

You have mention that, “The importance of each criteria was graded on a scale of 1 to 9”. Add the information for scaling each parameter into the table with their value and references for clear understanding.

2.4. Validation of Results. How many total wells are present in the study area and why you have selected on nine for validation? How you have selected those nine wells? Are they well representation of your study area data? Here you can select the well from your each of the study zone as I have suggested you to divide your study area in zones for easy understanding of the readers.

Represent the figure-2 in a more beautiful way and you can add colors in that figure.

3.1.1. Lineament Density, you have mentioned about the rating 4 and 5 and then results but here you have to mention only the results and data about the values and rating should be moved to the methodology section. Also do the same for your next headings in the results section where you have mentioned rating for each heading. Or you can mention each rating in a separate table for easy understanding.

Divide the figure-3 into two figures and discuss them accordingly in the article.

In table-6, you can also mention zone-1 to zone-5 and use that annotation in your whole manuscript.

In figure-5, you should use more data for the validation of groundwater potential zone using borehole yield data. The only 9 values are very limited data for validation. If there are more than 1000 water pumps and more than 500 tube wells than how those nine values are good representation of the study area. The total number of water pumps and tube well information is missing in your article.

The serious concern is about the discussion section of the article which needs a more detailed discussion of the article with the latest citations.

The conclusion of the article also needs revisions and mentioned your study area highlighted results in it.

Author Response

Response to Reviewer 3 Comments

General Comments:

Point 01: The research article is designed to study the “Sustainable Groundwater Potential Zoning with Coupling GIS, Remote Sensing and AHP Model: A Case from Northeast Bangladesh”. This study analyzed hydrologic and geographic attributes of the study area Mymensingh district and identified eight major factors influencing groundwater recharge potential, viz. geomorphology, land use/land cover, drainage density, lineament density, soil type, slope, elevation, and annual rainfall.

The article has some Grammar and English language mistakes therefore, I would recommend proofreading the article from an English native speaker.

My serious concern is about the discussion section of the article, which needs improvements and more discussion with the latest literature.

The discrepancies of the article are mentioned below to improve its quality.

Response 01:

Dear Reviewer,

Thank you for taking the time to make such a thoughtful suggestion. Based on your comments, we've updated the entire manuscript. We made some changes during the review process to ensure that the findings were presented clearly. In addition, we proofread the document, focusing on grammatical and English language errors. The discussion section has been meticulously updated with the most recent findings and a detailed discussion.

 Revisions:

Point 01: The authors must write the problem statement of this particular study and also explain the objective of the article in the abstract.

Response 01: In the abstract section, we have included a problem statement for this study with specific objectives.

Point 02: The final map showed that 11.51% (504.09 km2), 22.74% (995.58 km2), 33.5% (1466.46 km2), 26.88% (1176.84 km2), and 5.37% (235.17 km2) of the study area are for very high, high, moderate, low, and very low groundwater potential zones, respectively. The author must give some suitable zone names to each value for more clear understating .i.e., zone-1 is very high and zone-5 is very low groundwater potential zones. Also mentioned those zones throughout the manuscript.

Also, add the “well yield” word in keywords.

Response 02: As per your suggestion, we have designated very high, high, moderate, low, and very low groundwater potential zones as zone-01 to zone-05. We've also included the keyword "well yield."

Point 03: Introduction section, 2^nd paragraph. You have mentioned that, The groundwater level was found to be depleted over the past decades in this district [8]. Kindly mention the duration i.e., 2000-2020 and mention the water depletion depth 60-80 feet, etc. according to your study area data.

Response 03: We have now added the information with proper citation in this section.

Point 04: Add more literature review data related to the use of advanced technologies, such as remote sensing and geographic information systems (GIS), for groundwater management to support your study.

Response 04: We have included a description of various advanced technologies for groundwater management in the third paragraph of the introduction, along with specific literature reviews.

Point 05: The Analytical Hierarchy Process (AHP) method has been adopted in many studies due to its superiority compared to other methods [21]. Kindly mention the good results (3-4) of the other study results to support the validity of this AHP method.

Response 05: We've included adequate literature reviews on AHP analysis.

Point 06: Clearly mention the objective and novelty statement of the study in the last paragraph of the introduction section.

Response 06: Specific objectives and justification of the study is included in the last paragraph of the introduction section.

Material and Methods

Point 07: You have mentioned that “as shown in Figure 2.1.”. Kindly correct the figure number.

Response 07: we have corrected it.

Point 08: 2.1. Description of the Study Area, in which you must mention the information of the number of households in the study area, number of water pumps, number of tube wells, and water are their discharge rate per annum according to the daily consumption of the study area population. Therefore, also mention the increase of the tube wells in recent time and how many wells get dry due to lowering of the groundwater table.

Response 08: We've included a few points based on your suggestions. Due to a lack of reliable data sources, some information was left out.

Point 09: 2.2. Description of Data, in which you have collected the data from different websites (BWDB, FAO and SGB and Earth Data Site of NASA) than you should mention the links of the sites therefore other could get easily access to those data site.

Response 09: In this section, we've included a table that lists the various types of data, data sources, and output layers.

Point 10: You have mentioned that, “30*30m spatial resolution”. Kindly use the correct mathematical signs.

Response 10: Thank you for your suggestion. We have now corrected it.

Point 11: You have mention that, “The importance of each criteria was graded on a scale of 1 to 9”. Add the information for scaling each parameter into the table with their value and references for clear understanding.

Response 11: For a better understanding, we've added detailed procedures of Saaty's AHP methodology.

Point 12: 2.4. Validation of Results. How many total wells are present in the study area and why you have selected on nine for validation? How you have selected those nine wells? Are they well representation of your study area data? Here you can select the well from your each of the study zone as I have suggested you to divide your study area in zones for easy understanding of the readers.

Represent the figure-2 in a more beautiful way and you can add colors in that figure.

Response 12: We used well yield data from the Bangladesh Water Development Board's (BWDB) eight sampling stations, which is a reliable source. "Nine wells" was a typo, which has been corrected. As per your suggestion, we've updated Figure 02 as well.

Point 13: 3.1.1. Lineament Density, you have mentioned about the rating 4 and 5 and then results but here you have to mention only the results and data about the values and rating should be moved to the methodology section. Also do the same for your next headings in the results section where you have mentioned rating for each heading. Or you can mention each rating in a separate table for easy understanding.

Response 13: In the methodology section, Table 6 shows the detailed ratings and weights assigned for each parameters. Following your recommendation, we've moved some data from the results section to the methodology section.

Point 14: Divide the figure-3 into two figures and discuss them accordingly in the article.

Response 14: This figure has been removed from the revised version, and regression and Pearson correlations analysis have been added to validate the model.

Point 15: In table-6, you can also mention zone-1 to zone-5 and use that annotation in your whole manuscript.

Response 15: We have assigned very high, high, moderate, low, and very low groundwater potential zones as zone-01 to zone-05, based on your suggestion.

Point 16: In figure-5, you should use more data for the validation of groundwater potential zone using borehole yield data. The only 9 values are very limited data for validation. If there are more than 1000 water pumps and more than 500 tube wells than how those nine values are good representation of the study area. The total number of water pumps and tube well information is missing in your article.

Response 16: There were only eight monitoring wells of Bangladesh Water Development Board in the study area. This issue has been included as a limitation of this research in the discussion section.

Point 17: The serious concern is about the discussion section of the article which needs a more detailed discussion of the article with the latest citations.

Response 17: The discussion section has been updated by adding all of the findings, recommendations, and connections to recent study.

Point 18: The conclusion of the article also needs revisions and mentioned your study area highlighted results in it.

Response 18: Thank you for your suggestions. We have revised all of the uncertainties in the result section.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The revised manuscript shows substantial improvements as compared that of earlier version. Majority of the comments are well addressed. However, three important issues have not been addressed properly. I am recalling those once again:

1. (earlier Minor 2): P: 4, L: 7-8 “All images were downloaded at level-1 geotiff format” ----Does the author developed LULC map based on level-1 data? Calculations or estimations derived from level-1 data has several accuracy issues. The author needs to add more explanation on the LULC classification. Which classification method was adopted? What were the classification accuracies?

2. (earlier Minor 4): The methodology as well as the results sections are not appropriately supported by existing literature. The authors have introduced weights and ratings for GWSPs (i.e. Table 6), that ultimately dictates the outcome of the research. What was the basis of assigning these weights and ratings? 

On the other hand, the newer version of the manuscript effectively has single literature supporting the results (P16: "Similar findings are found in the Teesta River basin, Bangladesh [77]"). The addition of this sentence (in the present form) adds little or no scientific resonance. Therefore, an improvement is suggested.

3. (earlier Minor 5): The validation part still remains the weakest section of the manuscript. The authors have added correlation results. However, the variables considered for the correlation assessment are still ambiguous. Correlation analysis were performed between groundwater potential zone values and real-time well yield data.  What are "groundwater potential zone values"?

Validation of predicted outcomes against only 8 observed well data is simply inadequate. Moreover, observed well data itself  might incorporate uncertainties (as it is was extrapolated from the measured data). 

Authors are suggested to provide proper validation results to convince the readers to trust the predicted GWPZs.  

Author Response

Please see the attachment

Author Response File: Author Response.docx

Reviewer 2 Report

The authors of the manuscript have done good work in addressing grammatical and content weaknesses.  The topic and the analysis are not particularly novel and I still question its contribution to the field.  

Author Response

Please see the attachment

Author Response File: Author Response.docx

Reviewer 3 Report

Accepted in current form.

Author Response

Please see the attachment

Author Response File: Author Response.docx