Fusion of Remote Sensing Data Using GIS-Based AHP-Weighted Overlay Techniques for Groundwater Sustainability in Arid Regions

Round 1

Reviewer 1 Report

=> The manuscript deals with the modeling water resources using integrated remote-sensing and GIS techniques. The paper is very well structured. The introduction is informative, providing an overview od the scientific problem addressed and info from other relevant researches. The methodology is sound and presents satisfactory results thus, leading to sound interpretation. I think overall the paper is not bad.

=> The objectives of the study should be defines in the introduction and there are collocated under the description of the remote-sensing and GIS techniques .

=> This study has a potential to cited by other studies but there is a need more comments about the discussion for each 11 predictatve GIS map description (lithology, radar intensity, lineaments, altitude, slope, depressions, surface curvature, topographic wetness factor (TWI), Runoff using physical characteristics of catchments, rainfall).

=> The paper title may be of too wide content - Modeling water resources using integrated remote-sensing and GIS techniques for arid regions sustainability. That is, narrow down title and method are proper

=> It would be better, the discussion in each separate investigatiions.

=> The reviewer thinks that the contribution of this work is marginal, thus it should be reconsider for publication after major revision.

=> An extensive study is presented in all different investigated study fields.

=> The main concern of the reviewer is the novelty and the contribution of this research. How this research provides an added scientific value in the field and what is the main contribution?

Author Response

Reviewer 1

=> The manuscript deals with the modeling water resources using integrated remote-sensing and GIS techniques. The paper is very well structured. The introduction is informative, providing an overview of the scientific problem addressed and info from other relevant researches. The methodology is sound and presents satisfactory results thus, leading to sound interpretation. I think overall the paper is not bad.

Response: Thank you for your positive comments that allowed us to greatly improve the quality of the manuscript. We agree for all your comments and we thank you very much for your kind efforts and detailed review.

=> The objectives of the study should be defines in the introduction and there are collocated under the description of the remote-sensing and GIS techniques.

Response: Thank you for pointing this out. The objectives are modified as your suggestion.

=> This study has a potential to cited by other studies but there is a need more comments about the discussion for each 11 predictive GIS map description (lithology, radar intensity, lineaments, altitude, slope, depressions, surface curvature, topographic wetness factor (TWI), Runoff using physical characteristics of catchments, rainfall).

Response: Thank you for pointing this out. The 11 factors are discussed in section 6 “Discussion”. 

=> The paper title may be of too wide content - Modeling water resources using integrated remote-sensing and GIS techniques for arid regions sustainability. That is, narrow down title and methods are proper

Response: Thank you for pointing this out. We agreed for your suggestion. The following title is suggested “Fusion of remote-sensing data using GIS-based AHP-weighted overlay techniques for groundwater sustainability in arid regions”

=> It would be better, the discussion in each separate investigations.

=> The reviewer thinks that the contribution of this work is marginal, thus it should be reconsider for publication after major revision.

Response: Thank you for your comment. The manuscript largely improved based on the editors/reviewers suggestions. 

=> An extensive study is presented in all different investigated study fields.

Response: Thank you for your comment. The manuscript benefited from your comments . 

=> The main concern of the reviewer is the novelty and the contribution of this research. How this research provides an added scientific value in the field and what is the main contribution?

Response: Thank you for your comment. The contribution of the manuscript is added to the end of the introduction section. 

Reviewer 2 Report

The paper is interesting. The results are clearly described. 

There are also a few minor comments:
1.    The introduction requires a better presentation of the novelty of this research, as well as consideration of the structure of the manuscript by sections.
2.    Formulas in lines 196, 197, 200, 212 poorly formatted.
3.    The title of Subsection 4.3 should begin with a capital letter.
4.    There are many citations from one of the coauthors (Farouk El-Baz).
5.    Data from 2014 are used for verification. Is there data that is more recent?

Author Response

Reviewer 2

The paper is interesting. The results are clearly described.

Response 1: Thank you for your comments that allowed us to greatly improve the quality of the manuscript. We agree for all your comments and we thank you very much for your kind efforts and detailed review.

There are also a few minor comments:

1.    The introduction requires a better presentation of the novelty of this research, as well as consideration of the structure of the manuscript by sections.

Response: Thank you for pointing this out. The introduction section is updated as your suggestions.

2. 
      Formulas in lines 196, 197, 200, 212 poorly formatted.

Response: Thank you for pointing this out. The equations are formulated as suggested.

3.    The title of Subsection 4.3 should begin with a capital letter.

Response: Thank you for pointing this out. The subsection is revised as suggested.

4.    There are many citations from one of the coauthors (Farouk El-Baz).

Response: Thank you for pointing this out. The cited papers of Farouk El-Baz are related to the studied topic, and we deleted three references as suggested.

5.    Data from 2014 are used for verification. Is there data that is more recent?

Response: Thank you for your comment. The utilized Landsat-OLI data that was acquired on March 15, 2014 is immediately after storm and flood event on March 8-9, 2014. This is to verify the location of water accumulation.

Reviewer 3 Report

The topic of the study entitled “Modeling water resources using integrated remote-sensing and GIS techniques for arid regions sustainability” is an interesting one for readers and contributes to the development of knowledge in the field. It is a well-structured work. However, from my point of view it is necessary that the manuscript to be revision before publishing.

Below are my recommendations!

Reading the title, I expect in the manuscript that all existing water resources have been modeled based on remote sensing and GIS techniques. Instead, this study sought to identify potential groundwater resources based on Digital Elevation Model (DEM) products, ALOS radar imagery, and TRMM precipitation, and Landsat 8 imagery was used for validation. Please consider replacing the terms water resources with "groundwater prospective zones" and removing or replacing the term remote sensing. From my point of view, the DEM even if it is based on remote sensing data, this is a finished product, at the last level of processing and I have not seen it included in remote sensing data so far. It's just a personal opinion.

L136-141: Are “SRTMDEM data”, “SRTM data” and “SRTM DEM data” the same product? Please be consistent in terminology.

L144: Were other morphometric parameters calculated than those mentioned above? Please mention them!

L148: Please specify the “parameters” referred to in this sentence.

L153-155: Please add a paragraph describing the methods by which the geology and vegetation of the study area were identified based on Landsat 8 images. Please also specify what the terms "geological and vegetated" refer to. Do they represent rock types and vegetation types? Has a classification been made to identify them? Please detail!

L156-157: Are “elevation parameters” the parameters mentioned in lines 142-144 or are they different?

Is "drainage networks" the same product as "stream-networks" mentioned above? Please be consistent in terminology or describe it if it is a different product!

"Infiltration" how was this product obtained? Please detail!

Does the term "relief" refer to landforms?

L163-166: Please specify the date of the image, the processing level and for what purpose this image was used.

L173: What are the hydrologic data used? I have not seen it described before!

I recommend inserting a table in which all the data used in the modeling are summarized.

L208-209: “the groundwater potential zone map” or “groundwater prospective zones map”?

L238: It would be useful to add a column with the units of measurement of the parameters presented in Table 3.

L250: What does "viz." mean? What is the unit of measurement for this product? Are the values measured in dB? I would suggest you also consider to use a soil moisture product! From my point of view, it would be much more relevant than radar intensity.

L287: Does the term "Altitude" represent "Topography" in Table 3? Please be consistent in terminology!

L308: “ranges from 0 to 57.35”, what is the unit of measurement used for the slope? Degree or percent?

L323: Please specify the name of the tool in the spatial analysis package of Arc Map with which you obtained the "Depressions" product.

L324: Please explain how the “depressions” product obtained from SRTMDEM was validated using DEM and ALOS / PALSAR data! To validate a product, it is not recommended to use the same data.

L324-326: Please specify the unit of measurement!

L456-459: Please reformulate! I only counted 10 inputs; runoff is missing. I suggest that these inputs be grouped into the 4 categories listed above.

L488-526: Please consider breaking the paragraph into several smaller paragraphs. It is difficult to follow in its current form.

L491: Please check, Fig.13?

L536: Please check, Fig.13 a?

Author Response

Reviewer 3

The topic of the study entitled “Modeling water resources using integrated remote-sensing and GIS techniques for arid regions sustainability” is an interesting one for readers and contributes to the development of knowledge in the field. It is a well-structured work. However, from my point of view it is necessary that the manuscript to be revision before publishing.

Response 1: Thank you for your comments that allowed us to greatly improve the quality of the manuscript. We agree for all your comments and we thank you very much for your kind efforts and detailed review.

Below are my recommendations!

 Reading the title, I expect in the manuscript that all existing water resources have been modeled based on remote sensing and GIS techniques. Instead, this study sought to identify potential groundwater resources based on Digital Elevation Model (DEM) products, ALOS radar imagery, and TRMM precipitation, and Landsat 8 imagery was used for validation. Please consider replacing the terms water resources with "groundwater prospective zones" and removing or replacing the term remote sensing. From my point of view, the DEM even if it is based on remote sensing data, this is a finished product, at the last level of processing and I have not seen it included in remote sensing data so far. It's just a personal opinion.

Response: Thank you for your positive comments that allowed us to greatly improve the quality of the manuscript. Your opinion is right, but we tried to minimize the title. The SRTM DEM, ALOS/PALSAR, TRMM, and Landsat 8, all are remote-sensing data. Although, the groundwater prospective zones is appropriate, but we recommend give abroad attractive title to readers with the same meaning but in different words. Thus, we recommend the following title if you do not mind “Fusion of remote-sensing data using GIS-based AHP-weighted overlay techniques for groundwater sustainability in arid regions”

L136-141: Are “SRTMDEM data”, “SRTM data” and “SRTM DEM data” the same product? Please be consistent in terminology.

Response: Thank you for pointing this out. The “SRTM DEM data” are unified as suggested.

L144: Were other morphometric parameters calculated than those mentioned above? Please mention them!

Response: Thank you for your comment. The morphometric parameters are listed in lines 157 – 161.

L148: Please specify the “parameters” referred to in this sentence.

Response: Thank you for pointing this out. The “parameters” are specified as suggested. 

L153-155: Please add a paragraph describing the methods by which the geology and vegetation of the study area were identified based on Landsat 8 images. Please also specify what the terms "geological and vegetated" refer to. Do they represent rock types and vegetation types? Has a classification been made to identify them? Please detail!

Response: Thank you for pointing this out. The vegetation index derived from Landsat-8 is added in lines 169 – 174 to display vegetated areas and evidence of surface water. The geologic rock units are derived from Conoco geological map.   

L156-157: Are “elevation parameters” the parameters mentioned in lines 142-144 or are they different?

Response: Thank you for pointing this out. The “elevation parameters” are specified in lines 176 -177.

Is "drainage networks" the same product as "stream-networks" mentioned above? Please be consistent in terminology or describe it if it is a different product!

Response: Thank you for pointing this out. The "drainage networks" are unified as suggested.

"Infiltration" how was this product obtained? Please detail!

Response: Thank you for your comment. The “Infiltration" is estimated in section 4.10 after converting the morphometric parameters into runoff which then reversed into infiltration. To reduce confusion, we deleted the “Infiltration” and add “morphometric” in line 178.

Does the term "relief" refer to landforms?

Response: Thank you for your comment. The "relief" is deleted as we used altitudes, slope, curvatures and depressions instead.  

L163-166: Please specify the date of the image, the processing level and for what purpose this image was used.

Response: Thank you for pointing this out. A subset of ALOS/PALSAR-2 mosaic that published by Jaxa in 2017 with 25 m resolution is used to distinguish the fine-grained deposits (fluvial deposits) due to specular reflection from the rough surface (bed rocks).

L173: What are the hydrologic data used? I have not seen it described before!

Response: Thank you for pointing this out. The hydrologic data is updated (e.g., drainage density and TWI).

I recommend inserting a table in which all the data used in the modeling are summarized.

Response: Thank you for pointing this out. We tried to minimize the numbers of tables by adding two tables in supplementary data (Appendices).

L208-209: “the groundwater potential zone map” or “groundwater prospective zones map”?

Response: Thank you for pointing this out. We unified it to “groundwater prospective zones map” (GWPZs)?

L238: It would be useful to add a column with the units of measurement of the parameters presented in Table 3.

Response: Thank you for pointing this out. Measurements of some parameters are listed in front of the parameters.

L250: What does "viz." mean? What is the unit of measurement for this product? Are the values measured in dB? I would suggest you also consider using a soil moisture product! From my point of view, it would be much more relevant than radar intensity.

Response: Thank you for pointing this out. Your opinion is very good and I will use it on the ongoing research works. I utilized the radar backscatter here to distinguish the variability in soil and bedrock textures which also is significant in runoff and infiltration capacity.

- The “viz.” is used in written English to introduce a list of specific items or examples

- The backscatter values represented in Digital Numbers to stretch the data to get better visual intrpretation. The DN values can be converted to gamma naught values in decibel unit (dB) using the following equation:  γ₀ = 10 log₁₀ (DN²) - 83.0 dB, and no need to do it.

L287: Does the term "Altitude" represent "Topography" in Table 3? Please be consistent in terminology!

Response: Thank you for pointing this out. The “Altitude” is a kind of “topographic parameters” e.g., altitude, slope, curvature, and depressions. Therefore, we modified it to “altitude”.

L308: “ranges from 0 to 57.35”, what is the unit of measurement used for the slope? Degree or percent?

Response: Thank you for your comment. The slope here is represented in degrees.

L323: Please specify the name of the tool in the spatial analysis package of Arc Map with which you obtained the "Depressions" product.

Response: Thank you for your comment. The topographic depression is estimated by subtracting the initial DEM from the filled-DEM (Fill tool of Hydrology in Spatial Analyst tools).

L324: Please explain how the “depressions” product obtained from SRTMDEM was validated using DEM and ALOS / PALSAR data! To validate a product, it is not recommended to use the same data.

Response: Thank you for your comment. The extracted “depressions” obtained from the fill-differences of SRTM DEM was validated using ALOS / PALSAR, NDVI and Landsat-OLI 7, 5, and 3 in RGB (Fig. 12). The data DEM is displayed in figure (7c, e) to displays the elevation profiles e.g., X - Y and C – D that visualized the elevation contrasts.

L324-326: Please specify the unit of measurement!

Response: Thank you for your comment. The unit is specified as suggested.

L456-459: Please reformulate! I only counted 10 inputs; runoff is missing. I suggest that these inputs be grouped into the 4 categories listed above.

Response: Thank you for your comment. We updated the inputs into 11 by adding the missing “runoff” layer that derived from “morphometric parameters”. We categorized the final map into 5 categories to give high accuracy for each class.    

L488-526: Please consider breaking the paragraph into several smaller paragraphs. It is difficult to follow in its current form.

Response: Thank you for your comment. The paragraph is divided into many small paragraphs.

L491: Please check, Fig.13?

Response: Thank you for your comment. Thank you for your comment. It modified to Fig. 12.

L536: Please check, Fig.13 a?

Response: Thank you for your comment. Thank you for your comment. It modified to Fig. 12a.

Round 2

Reviewer 1 Report

Now, it seems much improved and I agree to accept the manuscript.

Author Response

Reviewer 1

Response: Thank you for your positive comments that allowed us to greatly improve the quality of the manuscript. We agree for all your comments and we thank you very much for your kind efforts and detailed review.

Reviewer 3

Comments and Suggestions for Authors

I thank the authors for their efforts to respond to all my comments in the cover letter, but there are still minor revisions that need to be made for a good understanding of the study by the readers. Please read my comments carefully and make changes to the text!

Response: We thank you for your positive comments that allowed us to greatly improve the quality of the manuscript. We agree for all your comments and we thank you very much for your kind efforts and detailed review.

Comment: "If the morphological parameters are listed between lines 157-161, please rephrase the sentence for proper meaning. Please move "and morphometric parameters" before the referenced parameters"!

Response: Thank you for your comment. The morphometric parameters now are listed in lines 158 – 161 and marked in blue color.

Comment: Lines 162-164 were completed with the phrase: “The latter parameters such as bifurcation ratio, elongation ratio, form factor, circularity ratio, drainage texture, stream Frequency, drainage density, length of overland flow, infiltration number, basin relief, relief ratio , and ruggedness (Appendices 1, 2)…”. Therefore, it is understood that the“ morphometric parameters” referred to above are the parameters listed in lines 162-164. Please check!

Response: Thank you for your comment. The morphometric parameters in the submitted R2 are listed in lines 158 – 161: "…….parameters such as bifurcation ratio, elongation ratio, form factor, circularity ratio, drainage texture, stream Frequency, drainage density, length of overland flow, infiltration number, basin relief, relief ratio, and ruggedness (Appendices 1, 2) are calculated using mathematical formula as depicted in the literature of Abdelkareem [15]".

Comment: L178: Please, instead of white / dark tone, mention the NDVI value ranges between which the vegetation and water are found in the study area!

Response: Thank you for pointing this out. We updated the manuscript with these sentences:  "The high values close to +1 (white tone) of NDVI refer to vegetated areas but low values close to -1 (dark tone) indicate probable water signatures. In the present study, NDVI values of the wet areas that display evidence of water signatures range from - 0.015 to 0.07, and the vegetated areas range from 0.11 to 0.55". 

L362: "ranges from 0 to 57.35" please add the unit of measurement!

Response: Thank you for pointing this out. The phrase modified to "…ranges from 0 to 57.35 degree…"

Reviewer 3 Report

I thank the authors for their efforts to respond to all my comments in the cover letter, but there are still minor revision that need to be made for a good understanding of the study by the readers. Please read my comments carefully and make changes to the text!

If the morphological parameters are listed between lines 157-161, please rephrase the sentence for proper meaning. Please move "and morphometric parameters" before the referenced parameters!

Lines 162-164 were completed with the phrase: “The latter parameters such as bifurcation ratio, elongation ratio, form factor, circularity ratio, drainage texture, stream Frequency, drainage density, length of overland flow, infiltration number, basin relief, relief ratio , and ruggedness (Appendices 1, 2)…”. Therefore, it is understood that the“ morphometric parameters” referred to above are the parameters listed in lines 162-164. Please check!

L178: Please, instead of white / dark tone, mention the NDVI value ranges between which the vegetation and water are found in the study area!

L362: "ranges from 0 to 57.35" please add the unit of measurement!

All the best!

Author Response

Reviewer 3

Comments and Suggestions for Authors

I thank the authors for their efforts to respond to all my comments in the cover letter, but there are still minor revisions that need to be made for a good understanding of the study by the readers. Please read my comments carefully and make changes to the text!

Response: We thank you for your positive comments that allowed us to greatly improve the quality of the manuscript. We agree for all your comments and we thank you very much for your kind efforts and detailed review.

Comment: "If the morphological parameters are listed between lines 157-161, please rephrase the sentence for proper meaning. Please move "and morphometric parameters" before the referenced parameters"!

Response: Thank you for your comment. The morphometric parameters now are listed in lines 158 – 161 and marked in blue color.

Comment: Lines 162-164 were completed with the phrase: “The latter parameters such as bifurcation ratio, elongation ratio, form factor, circularity ratio, drainage texture, stream Frequency, drainage density, length of overland flow, infiltration number, basin relief, relief ratio , and ruggedness (Appendices 1, 2)…”. Therefore, it is understood that the“ morphometric parameters” referred to above are the parameters listed in lines 162-164. Please check!

Response: Thank you for your comment. The morphometric parameters in the submitted R2 are listed in lines 158 – 161: "…….parameters such as bifurcation ratio, elongation ratio, form factor, circularity ratio, drainage texture, stream Frequency, drainage density, length of overland flow, infiltration number, basin relief, relief ratio, and ruggedness (Appendices 1, 2) are calculated using mathematical formula as depicted in the literature of Abdelkareem [15]".

Comment: L178: Please, instead of white / dark tone, mention the NDVI value ranges between which the vegetation and water are found in the study area!

Response: Thank you for pointing this out. We updated the manuscript with these sentences:  "The high values close to +1 (white tone) of NDVI refer to vegetated areas but low values close to -1 (dark tone) indicate probable water signatures. In the present study, NDVI values of the wet areas that display evidence of water signatures range from - 0.015 to 0.07, and the vegetated areas range from 0.11 to 0.55". 

L362: "ranges from 0 to 57.35" please add the unit of measurement!

Response: Thank you for pointing this out. The phrase modified to "…ranges from 0 to 57.35 degree…"