Assessment of Water Quality in Lake Qaroun Using Ground-Based Remote Sensing Data and Artificial Neural Networks

Round 1

Reviewer 1 Report

General comments:

In my opinion this paper is an interesting study and authors have presented new indices to analyze water quality in lakes. Because water environment protection are one of the most important problems due to climate changes it is necessary to find new methods and techniques to monitor water quality changes. The paper is generally well written and structured. My main concern regarding to the methodology is lack of information about applied interpolation method including selection training and testing points. In my opinion important weakness of this study is lack of discussion which is necessary when new indices or methods are presented (advantages and limitations on the background of other methods). All shortcomings were presented below.

Specific comments:

• Line 13. [email protected] (M.I.) – I don’t see this author in the authors list. Please delete e-mail from line 13 or add author to author list. Additionally, I don’t see his initials in the author contributions (lines 595 – 599).
• Abstract is too long. Lines 29-34 are not necessary, it’s good sentence to introduction or discussion chapter, not for abstract. Please add main aim of the study.
• Introduction is well written and has enough literature. Main concern are novelty of cited papers, some of them are from 1997 – 2012. Please replace (if it is possible) or add citations of newest literature (from 2020-2021).
• Lines 75-185 should be moved into study site and description. In introduction chapter please focus on problem generally, on the basis of examples in the whole World, not your study area.
• Line 191. Figure 1. Please move legend and scale below, into white background. In currect version it is illegible, for example 6 from scale bar and sign of water samples could be wrong interpretate as a water sample no. 6.
• Line 198. Please add information about accuracy and possible measurement error of MAGELLAN GPS 315.
• Line 204. Please add information about accuracy and possible measurement error of YSI Professional Plus.
• Line 207. Please add information about accuracy and possible measurement error of HI 81226.
• Line 199. Authors wrote “Sampling locations were selected carefully within the Qaroun Lake to have a good representation of the spatial variability of quality indicators across the entire lake”. What criterias where analyzed to select this locations (for example bathymethry plan of the lake)?
• Line 219. Why authors selected IDW method? I agree that it is one of the most applicable interpolation methods but in some cases, different methods are better, for example Kriging. Did authors checked different methods to select the most applicable of them? How many sample stations were used as training stations and how many as testing? Which method was selected to select testing stations? Please add this information.
• Line 255. Please move equation to the centre and add sentence “where: RSI – ratio spectral index, R1 - covering central wavelengths … add proper value, R2 - covering central wavelengths … add proper value”.
• Line 260. The same comment as above.
• Line 288. Please move equation to the centre.
• Line 294. Please move equation to the centre.
• Line 301. Please move equation to the centre.
• Line 314. Please move equation to the centre.
• Line 316. Please move equation to the centre.
• Line 541. It is not a table. Please change it as a figure and move it and description to methodology chapter. Remember to change numbers of other figures and tables, also in text. Rest of the results are generally well described and figures/tables are good presented.
• Discussion – I know that it is not necessary chapter but in case of this work it should be added. Authors tested new spectral indices and used ANNs models. Please add information about advantages and limitation of these spectral indices and applied models on the background of other studies. Additionally, authors used Ground Based Remote Sensing Data, please try to discuss about advantages and limitation of this data comparing to different remote sensing sources (UAVs, satellites).
• Line 597. supervision, A.B.G. – I don’t see this author in the author list, maybe it should be A.M.G.?

Author Response

Reviewer 1

General comments:

In my opinion this paper is an interesting study and authors have presented new indices to analyze water quality in lakes. Because water environment protections are one of the most important problems due to climate changes it is necessary to find new methods and techniques to monitor water quality changes. The paper is generally well written and structured. My main concern regarding to the methodology is lack of information about applied interpolation method including selection training and testing points. In my opinion important weakness of this study is lack of discussion which is necessary when new indices or methods are presented (advantages and limitations on the background of other methods). All shortcomings were presented below.

We greatly appreciate your critical observations as well as your constructive and helpful comments. We hope that we could address your questions/comments by the explanations and revisions made in the manuscript. We believe that the manuscript is substantially improved after making the suggested revisions.

Specific comments:

• Line 13. [email protected] (M.I.) – I don’t see this author in the authors list. Please delete e-mail from line 13 or add author to author list. Additionally, I don’t see his initials in the author contributions (lines 595 – 599).

Response: We greatly appreciate your critical observations. This e-mail was deleted from the manuscript.

 Abstract is too long. Lines 29-34 are not necessary, it’s good sentence to introduction or discussion chapter, not for abstract. Please add main aim of the study.

Response: Many thanks for this comment. This sentence was deleted from the abstract section. The introduction section has sentence revealed the same meaning of the deleted sentence. The main objective of the study was already presented in the abstract section from lines 39to 43.

• Introduction is well written and has enough literature. Main concern are novelty of cited papers, some of them are from 1997 – 2012. Please replace (if it is possible) or add citations of newest literature (from 2020-2021).

Response: Many thanks for your constructive comments. The recent and new citations were added in the introduction section.

• Lines 75-85 should be moved into study site and description. In introduction chapter please focus on problem generally, on the basis of examples in the whole World, not your study area.

Response: Many thanks for this comment. The sentence from lines 75 to 85 in the introduction section were moved into study site and description as you suggested (Lines 2231to 229).

• Line 191. Figure 1. Please move legend and scale below, into white background. In correct version it is illegible, for example 6 from scale bar and sign of water samples could be wrong interpretate as a water sample no. 6.

Response: We greatly appreciate your critical observations. Figure 1 was modified as you suggested.

• Line 198. Please add information about accuracy and possible measurement error of MAGELLAN GPS 315.

Response: Many thanks for this comment. The information about accuracy and measuring error was added under sampling and analyses section.

• Line 204. Please add information about accuracy and possible measurement error of YSI Professional Plus.

Response: Many thanks for this comment. The information about accuracy and measuring error was added under sampling and analyses section.

• Line 207. Please add information about accuracy and possible measurement error of HI 81226.

Response: Many thanks for this comment. The information about accuracy and measuring error was added under sampling and analyses section.

• Line 199. Authors wrote “Sampling locations were selected carefully within the Qaroun Lake to have a good representation of the spatial variability of quality indicators across the entire lake”. What criterias where analyzed to select this locations (for example bathymetry plan of the lake)?

Response: Many thanks for this comment. Accuracy of identifying locations was maintained by repeatedly determining the location of fixed points according to the sources of pollution (Line 246 to 248).

• Line 219. Why authors selected IDW method? I agree that it is one of the most applicable interpolation methods but in some cases, different methods are better, for example Kriging. Did authors checked different methods to select the most applicable of them? How many sample stations were used as training stations and how many as testing? Which method was selected to select testing stations? Please add this information.

Response: Many thanks for this comment. One of the efficient methods to specify the most suitable interpolation method for the studied parameters is the calculation of the root mean square error (RMSE) by doing an aggregate error analysis on the interpolation following across validation routine. It can be done by removing one data point at a time and estimates its value using the interpolation method and all other data points. This way generates a residual error at each data point location (residual error = measured data value at the point - estimated value). This technique was applied on all the samples .The RMSE is calculated from the collection of residual errors. RMSE of IDW and kriging interpolation were compared and it was found that the IDW interpolation method has a lower RMSE so it was used for generating the spatial maps distribution of the water quality indicators. The explanation was added under section (2.3. Spatial Distributions of Water Quality).

• Line 255. Please move equation to the centre and add sentence “where: RSI – ratio spectral index, R1 - covering central wavelengths … add proper value, R2 - covering central wavelengths … add proper value”.

Response: Thanks for your valuable suggestions. We have modified the equation to the center and added more detailed information about the equation in the lines

• Line 260. The same comment as above.
• Line 288. Please move equation to the centre.
• Line 294. Please move equation to the centre.
• Line 301. Please move equation to the centre.
• Line 314. Please move equation to the centre.
• Line 316. Please move equation to the centre.

Response: Thanks for your accurate observations. We have moved the equation to the center.

• Line 541. It is not a table. Please change it as a figure and move it and description to methodology chapter. Remember to change numbers of other figures and tables, also in text. Rest of the results is generally well described and figures/tables are good presented.

Response: We greatly appreciate your critical observations. Table 7 was changed to Figure 6 and all modified numbers were done. 

• Discussion – I know that it is not necessary chapter but in case of this work it should be added. Authors tested new spectral indices and used ANNs models. Please add information about advantages and limitation of these spectral indices and applied models on the background of other studies. Additionally, authors used Ground Based Remote Sensing Data, please try to discuss about advantages and limitation of this data comparing to different remote sensing sources (UAVs, satellites).

Response: Thanks for your valuable suggestions. We added new section before the conclusion section under this title (Advantages and limitations of our research and expected future work)                                                                                                                    

• Line 597. Supervision, A.B.G. – I don’t see this author in the author list, may be it should be A.M.G.?

Response: We greatly appreciate your critical observations. Supervision, A.B.G. was modified to A.M.G.

Author Response File: Author Response.docx

Reviewer 2 Report

The manuscript “water-1435618” deals with the assessment of WQI using multiple approaches including ground sampling, satellite data analysis and ANNs model. It is an comprehensive investigation conducted by wide range of researchers from multiple institutes, however, in doing so, the overall length of current manuscript is much more than it should be. For instance, there is a dire need to briefly explain each section in order to shorten its length. Otherwise, gathering of so many components along with more details might loose attention of wide range of researchers and readers. In addition, such write up style may create confusion among readers in terms of pointing out the main objectives of current study. Else, the following points must be addressed for improving the quality, readability and significance of current study. These includes:

• The sentence formation and English writing style required serious attention and needs extensive checking from MDPI service or any other appropriate English checking institute.
• The abbreviations are widely used in main text and throughout manuscript. Please make separate section of abbreviation and write all terms.
• The abstract itself is too confusing and requires to be improved in scientific means. Further, the length of abstract must not exceed 300 words at most, otherwise the purpose of abstract fails.
• Add some facts and figures of surface water quality around the globe in your introduction.
• Reduce length of introduction.
• Line 171! Is it WOI or WQI. Make correction.
• The key words should be mentioned whenever first time using any abbreviation,
• Improve your location site/ map for better reading and understanding it. (Mark points and site names).
• Did you perform sampling on source points from eastern and southern drains mentioned? Justify it.
• Why did you take only mentioned physicochemical parameters?? Justify it.
• Line 244! What is SRI?
• You used ANN model, do share its results table and respective algorithm for better understanding in supplementary information. How you compared different parameters in it? Provide details.
• Table 2, Line 333! Units are mentioned at the end. It is always preferred to write unit in main table right after each term. Similar for Table 3 as well.
• Table 3, Line no 352! Table is confusing in a way that researchers used small alphabets a, b, c, d , f, g? What do they mean by it? It’s hard to understand such table.
• In results, compare your answers with surface water quality standards by WHO.
• Line 407! you can use different colors to explain spatial distribution of years 2018 and 2019.
• Reduce the text in heading mention in line no 458 i.e “Performance of Different SRIs to assess Water Quality Indices”
• 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.
• You can also make Water Quality index of overall study area by considering all parameters.
• Explain in detail Table 5, Line 456.

Your submitted manuscript must address all these questions in order to enhance its quality and suitability for acceptance in “Water”.

Author Response

Reviewer 2

The manuscript “water-1435618” deals with the assessment of WQI using multiple approaches including ground sampling, satellite data analysis and ANNs model. It is a comprehensive investigation conducted by wide range of researchers from multiple institutes, however, in doing so, the overall length of current manuscript is much more than it should be. For instance, there is a dire need to briefly explain each section in order to shorten its length. Otherwise, gathering of so many components along with more details might lose attention of wide range of researchers and readers. In addition, such write up style may create confusion among readers in terms of pointing out the main objectives of current study. Else, the following points must be addressed for improving the quality, readability and significance of current study. These include:

We greatly appreciate your critical observations as well as your constructive and helpful comments. We hope that we could address your questions/comments by the explanations and revisions made in the manuscript. We believe that the manuscript is substantially improved after making the suggested revisions.

• The sentence formation and English writing style required serious attention and needs extensive checking from MDPI service or any other appropriate English checking institute.

Response: Many thanks for this comment. English writing was improved as you suggested.

• The abbreviations are widely used in main text and throughout manuscript. Please make separate section of abbreviation and write all terms.

Response: Many thanks for this comment. Abbreviations in the manuscript were added in a separated section as you suggested before the introduction section.

 The abstract itself is too confusing and requires to be improved in scientific means. Further, the length of abstract must not exceed 300 words at most, otherwise the purpose of abstract fails.

Response: Many thanks for this comment. Abstract section was improved and reduced as possible as you suggested.

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

Response: Many thanks for this comment. Already, some facts of surface water quality were presented in the introduction section (Lines 72 to 78).

 

• Reduce length of introduction.

Response: Many thanks for this comment. The length of introduction was reduced as you suggested by deleted unnecessary sentences.

• Line 171! Is it WOI or WQI? Make correction.

We are greatly appreciate your critical observations. WQI is correct.  

The key words should be mentioned whenever first time using any abbreviation.

Response: Many thanks for this comment. The key words were mentioned in the first time using abbreviation in all manuscript as you suggested.

• Improve your location site/ map for better reading and understanding it. (Mark points and site names).

Response: We greatly appreciate your critical observations. The location map was modified for better reading and understanding as you suggested.

• Did you perform sampling on source points from eastern and southern drains mentioned? Justify it.
• Response: Many thanks for this comment. The samples of the pollution source points from the eastern and southern drains were collected, analyzed, so that we mentioned it in the Study Site and Description under materials and methods section.
• Why did you take only mentioned physicochemical parameters?? Justify it.

Response: Many thanks for this comment. The mentioned physicochemical parameters including TN, NH₄⁺, PO₄^3-, and COD provides a valuable framework for defining particular environmental problems, and sharing knowledge on water quality utilization for aquatic life according to CCME 2007, in addition these parameters are correlated with spectral indices of remote sensing data.

 Line 244! What is SRI?

Response: Thank you for your careful examination. We added the explanation of SRI in line 170 .                           

• You used ANN model, do share its results table and respective algorithm for better understanding in supplementary information. How you compared different parameters in it? Provide details.

Response: Many thanks for this comment. The provide details about compared different parameters was written under section (2.6.1. Back-Propagation Neural Network) from line 383 to 390.

 

Table 2, Line 333! Units are mentioned at the end. It is always preferred to write unit in main table right after each term. Similar for Table 3 as well.

Response: Many thanks for this comment. The units of the parameters were added in the main tables 2 and 3 as you suggested. 

• Table 3, Line no 352! Table is confusing in a way that researchers used small alphabets a, b, c, d, f, g? What do they mean by it? It’s hard to understand such table.

Response: Many thanks for this comment. The explanation of the letters mean was added under the table 3.

• In results, compare your answers with surface water quality standards by WHO.

Response: Many thanks for this comment. The surface water quality in the study area was assessed for aquatic utilization according to CCME (Canadian Council of Ministers of the Environment), since the World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO constitution states its main objective as "the attainment by all peoples of the highest possible level of health".

• Line 407! you can use different colors to explain spatial distribution of years 2018 and 2019.

Response: Many thanks for this comment. The spatial distribution maps of years 2018 and 2019 were modified using different colors as you suggested.

• Reduce the text in heading mention in line no 458 i.e “Performance of Different SRIs to assess Water Quality Indices”

Response: Many thanks for this comment. It was done.

• 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: Many thanks for this comment. The conclusion was shorted and the future work was written under new section (4. Advantages and limitations of our research and expected future work).                           

* You can also make Water Quality index of overall study area by considering all parameters.

Response: Many thanks for this comment. We will consider your suggestion in our future work to link between WQI, pollution indices with spectral indices and ANN.

• Explain in detail Table 5, Line 456.

Response: Many thanks for this comment. We explained the title of Table 5 in details.

Your submitted manuscript must address all these questions in order to enhance its quality and suitability for acceptance in “Water”.

We are greatly appreciate your critical observations as well as your constructive and helpful comments.

 

Author Response File: Author Response.docx

Reviewer 3 Report

Dear Authors

I went through your manuscript and found it can be interesting for readers. However, i have some major comments/suggestions that can increase the scientific merit of the manuscript and its readability. Please see my comments as follows:

 

General Comment

What do you mean by WQI? Did you use a WQI model? Or, you used this term for individual water quality parameters? If so, it is not correct to call water quality parameters as WQI. Please change WQI to “water quality parameter” or simply “water quality constituents”. “Water quality indices” is a term usually to refer to WQI models in the water quality community. Please differentiate between “water quality indicator” and “water quality index”.

I think you mean orthophosphate (PO43-). PO42- is not a relevant water quality parameter. If so, please revise it across the manuscript.

 

ABSTRACT

L36: Please see my general comment.

What do you mean by WQI? Did you use a WQI model?

 

INTRODUCTION

L94-96: Please see my general comment.

L99: Please see my general comment.

L118-121: Please support with proper references. For your claim about the “statistical modeling to save money and time while increasing accuracy”, I suggest you to cite “Development and application of reduced-order neural network model based on proper orthogonal decomposition for BOD5 monitoring: Active and online prediction”.

A successful application of remote sensing technology to monitor water quality in the largest lake in the world, i.e., the Caspian Sea, is “Caspian Sea is eutrophying: the alarming message of satellite data”. I suggest the authors to address such successful applications in Introduction.

L160-161: Your study focus is on water quality. Please just give evidence of successful application of ANN in the field of water quality community (not water resources and hydrological time series) (e.g., A comprehensive uncertainty analysis of model-estimated longitudinal and lateral dispersion coefficients in open channels).

 

STUDY SITE AND DESCRIPTION

Would you please give more information about the lake (e.g., max depth, average precipitation and evaporation, the prevalent climate, mixing regime, warm monomictic or polymictic)?

L189-190: Please revise this statement (use better word instead of “evaporates”).

 

SAMPLING AND ANALYSES

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

Did you acidify your samples? Or you simply analyzed the samples within 48 hours? Please describe.

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

 

SPATIAL DISTRIBUTIONS OF WATER QUALITY INDICATORS

Why did you use IDW? Why not kriging? Please justify.

 

SPECTRAL REFLECTANCE MEASUREMENTS

I couldn’t find any references to support this section.

 

SELECTION OF PUBLISHED, NEWLY TWO AND THREE BAND SPECTRAL REFLECTANCE INDICES

I couldn’t find any references to support this section.

 

BACK-PROPAGATION NEURAL NETWORK (BPNN)

L271-284: These section is text book materials. Please shorten.

Please give more information with justification on the ANN used (e.g., number of neurons, activation functions, learning methods, training function). Please use this paper for further clarification and citation: “A framework development for predicting the longitudinal dispersion coefficient in natural streams using an artificial neural network”.

 

MODEL EVALUATION

Good.

 

DATA ANALYSIS

Good.

 

WATER QUALITY INDICES

Please give the units for water quality parameters in Table 2.

Please compared water quality levels in the lake with these two papers: “Hyper-Nutrient Enrichment Status in the Sabalan Lake, Iran” and “Complex dynamics of water quality mixing in a warm mono-mictic reservoir”.

Please use high resolution figures instead of Figures 2 and 3.

Table 3: What is your reference for classification of water quality parameters?

 

PERFORMANCE OF DIFFERENT SRIS TO ASESS WATER QUALITY INDICES

Did you check the significant level and multicolinearity in linear regression model used?

 

CONCLUSIONS

Please add limitations and future outlook for further investigation.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Author Response

Reviewer 3

I went through your manuscript and found it can be interesting for readers. However, i have some major comments/suggestions that can increase the scientific merit of the manuscript and its readability. Please see my comments as follows:

We greatly appreciate your critical observations as well as your constructive and helpful comments. We hope that we could address your questions/comments by the explanations and revisions made in the manuscript. We believe that the manuscript is substantially improved after making the suggested revisions.

 General Comment

What do you mean by WQI? Did you use a WQI model? Or, you used this term for individual water quality parameters? If so, it is not correct to call water quality parameters as WQI. Please change WQI to “water quality parameter” or simply “water quality constituents”. “Water quality indices” is a term usually to refer to WQI models in the water quality community. Please differentiate between “water quality indicator” and “water quality index”.

I think you mean orthophosphate (PO43-). PO42- is not a relevant water quality parameter. If so, please revise it across the manuscript.

Response: We greatly appreciate your critical observations as well as your constructive and helpful comments. The term of WQIs was changed to water quality parameters (WQPs) and also, the PO₄^2- was replaced by PO₄^3- in all manuscript as you suggested.

ABSTRACT

L36: Please see my general comment.

Response: We greatly appreciate your critical observations as well as your constructive comments. The term of WQIs was changed from water quality indices to water quality parameters (WQPs) and also, the PO₄^2- was replaced to PO₄^3- in all manuscript as you suggested.

What do you mean by WQI? Did you use a WQI model?

 Response: Many thanks for this comment. Water quality indices (WQIs) were replaced by water quality parameters (WQPs) in all manuscript.

INTRODUCTION

L94-96: Please see my general comment.

Response: We greatly appreciate your critical observations as well as your constructive comments. The term of WQIs were changed to WQPs as you suggested in all manuscript.

L99: Please see my general comment.

Response: We greatly appreciate your critical observations as well as your constructive comments. The PO₄^2- was replaced to PO₄^3- as you suggested in all manuscript.

L118-121: Please support with proper references. For your claim about the “statistical modeling to save money and time while increasing accuracy”, I suggest you to cite “Development and application of reduced-order neural network model based on proper orthogonal decomposition for BOD5 monitoring: Active and online prediction”.

 Response: Many thanks for this comment. Your suggested reference was added.

A successful application of remote sensing technology to monitor water quality in the largest lake in the world, i.e., the Caspian Sea, is “Caspian Sea is eutrophying: the alarming message of satellite data”. I suggest the authors to address such successful applications in Introduction.

 Response: Many thanks for this comment. Your suggested reference was added.

L160-161: Your study focus is on water quality. Please just give evidence of successful application of ANN in the field of water quality community (not water resources and hydrological time series) (e.g., A comprehensive uncertainty analysis of model-estimated longitudinal and lateral dispersion coefficients in open channels).

 Response: Many thanks for this comment. We have added two references to our manuscript since your suggest reference is related only to SVMR.

 STUDY SITE AND DESCRIPTION

Would you please give more information about the lake (e.g., max depth, average precipitation and evaporation, the prevalent climate, mixing regime, warm monomictic or polymictic)?

Response: Many thanks for this comment. More information about the Lake (e.g., max depth, average precipitation and evaporation, the prevalent climate, mixing regime, warm monomictic or polymictic) was added as you suggested (Lines 217 to 221).

 

L189-190: Please revise this statement (use better word instead of “evaporates”).

 Response: Many thanks for this comment. The word “evaporates” was changed to be “instead of” as you suggested (Line 236).

SAMPLING AND ANALYSES

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

Response: Many thanks for this comment. Detailed information about accuracy and manufacturer of the measuring and analyses instruments were added. The collected samples were taken manually from the surface water of the Lake without using sampler’s instrument (Lines 243 to 256).

Did you acidify your samples? Or you simply analyzed the samples within 48 hours? Please describe.

Response: We greatly appreciate your comment and critical observations. Sixteen water samples were collected in polyethylene bottles, labeled, kept in ice box, transferred to laboratory and analyzed within 48 hour (Lines 245 to 247).

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

Response: Many thanks for this comment. The methods used to analyze the water quality parameters were supported by reference.

 SPATIAL DISTRIBUTIONS OF WATER QUALITY INDICATORS

Why did you use IDW? Why not kriging? Please justify.

 Response: RMSE of IDW and kriging interpolation were compared and it was found that the IDW interpolation method has a lower RMSE so it was used for generating the spatial maps distribution of the water quality indicators.  More details about IWD selection was added under section 2.3. Spatial Distributions of Water Quality from line 281 to 288.

SPECTRAL REFLECTANCE MEASUREMENTS

I couldn’t find any references to support this section.

 Response: Many thanks for this comment. The references were added.

SELECTION OF PUBLISHED, NEWLY TWO AND THREE BAND SPECTRAL REFLECTANCE INDICES

I couldn’t find any references to support this section.

 Response: Many thanks for this comment. The reference was added.

 

BACK-PROPAGATION NEURAL NETWORK (BPNN)

 

L271-284: This section is text book materials. Please shorten.

Please give more information with justification on the ANN used (e.g., number of neurons, activation functions, learning methods, training function). Please use this paper for further clarification and citation: “A framework development for predicting the longitudinal dispersion coefficient in natural streams using an artificial neural network”.

 Response: Many thanks for this comment.  This section was shorten and the provide details (e.g., number of neurons, activation functions, learning methods, training function) was written under section (2.6.1. Back-Propagation Neural Network) from line 349 to 354 and the reference was added.

MODEL EVALUATION

Good.

 Many thanks for you.

DATA ANALYSIS

Good.

  Many thanks for you.

WATER QUALITY INDICES

Please give the units for water quality parameters in Table 2.

Response: Many thanks for this comment. The measuring units of water quality parameters were added in the table 2.

Please compare water quality levels in the lake with these two papers: “Hyper-Nutrient Enrichment Status in the Sabalan Lake, Iran” and “Complex dynamics of water quality mixing in a warm mono-mictic reservoir”.

Response: Many thanks for this comment. The comparison between the water quality levels in the Qaroun Lake and Sabalan Lake was made as you suggested (Lines 496to 502).

Please use high resolution figures instead of Figures 2 and 3.

Response: Many thanks for this comment. The high resolution of Figures 2 and 3 were added.

Table 3: What is your reference for classification of water quality parameters?

Response: Many thanks for this comment. Water quality parameters for aquatic utilization were classified according to CCME 2007 (Canadian Council of Ministers of the Environment) [56].

 PERFORMANCE OF DIFFERENT SRIS TO ASESS WATER QUALITY INDICES

Did you check the significant level and multicolinearity in linear regression model used?

Response: Many thanks for this comment. The significant level of linear regression model was added in the table 6.

CONCLUSIONS

Please add limitations and future outlook for further investigation.

Response: Thanks for your valuable suggestions. We added new section before the conclusion section under this title (Advantages and limitations of our research and expected future work).          

 

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The manuscript has been improved following the recommendations of the Reviewer; most of my concerns have been addressed and justified.

I believe that manuscript in present form can be accepted to publish in Water Journal.

Author Response

Reviewer 1

The manuscript has been improved following the recommendations of the Reviewer; most of my concerns have been addressed and justified.

I believe that manuscript in present form can be accepted to publish in Water Journal.

We greatly appreciate your critical observations as well as your constructive and helpful comments.

Author Response File: Author Response.docx

Reviewer 2 Report

This is my second review report for manuscript ““water-1435618”. The authors have somewhat put in their efforts in addressing my previous comments. However, some points are still not properly addressed by the researchers. Besides a major query regarding plagiarism has been identified in current study, which has greatly reduce the significance and novelty of current study. Along with my some unaddressed comments, my additional comments include following:

• The introduction section is too long. It was suggested to make it concise as much as possible. Rather than addressing this comment, authors further enhance the length of introduction by adding so many unnecessary information. It must be made better.
• The authors claim that English and technical writing has been improved, however from manuscript it seems that they haven’t gone through English checking by some professional English checking institute. Since there are still many sentences in the manuscript which are confusing and not written properly. I would recommend authors to address this issue.
• The Abbreviations section should be at the end of manuscript after Conflicts of Interest section. In addition, it should be presented in table form and include all key abbreviations and key words used in the manuscript. The authors must look into it as well.
• The abstract section needs a lot of improvement in scientific writing. There are many sentences which are not properly presented.
• The authors claimed that they address my comment “Add some facts and figures of surface water quality around the globe in your introduction.” In line 72 to 78. However, I didn’t find any details on facts and figures in these lines of the manuscript.
• The researchers didn’t appropriately indicate regarding changes done in manuscript. For example, I asked “Improve your location site/ map for better reading and understanding it. (Mark points and site names).” They just mentioned “We greatly appreciate your critical observations. The location map was modified for better reading and understanding as you suggested.” However, the researchers didn’t indicate page no, line no which makes reviewer very hard to follow the changes incorporated in the manuscript.
• The explanation of comment “You used ANN model, do share its results table and respective algorithm for better understanding in supplementary information. How you compared different parameters in it? Provide details.” is not satisfactory. The researchers are providing generic details regarding ANN model. It was recommended to add details in supplementary. Normally Visual Studio and R program is used for development of ANN model. Therefore, it was suggested to add the table as well as algorithm code in supplementary file to allow other researchers to reproduce your results and to ensure that ANN model has been properly applied to your data set.
• The researchers didn’t satisfactorily address this comment as well “In results, compare your answers with surface water quality standards by WHO.”

In addition, a lot of plagiarism has been identified in current manuscript. The researchers have copied 8% of the content from research article “Using Optimized Two and Three-Band Spectral Indices and Multivariate Models to Assess Some Water Quality Indicators of Qaroun Lake in Egypt” which is again alarming and overall, 23% plagiarism has been identified in the revised manuscript. Moreover, it has been identified that similar work with same experimental design has been already done by same researchers published on 18^th September 2021 in MDPI journal “Sustainability”. Therefore, I don’t think that this study is any more suitable and novel for publishing in MDPI journal “Water”.

Author Response

Reviewer 2

 

Comments and Suggestions for Authors

This is my second review report for manuscript ““water-1435618”. The authors have somewhat put in their efforts in addressing my previous comments. However, some points are still not properly addressed by the researchers. Besides a major query regarding plagiarism has been identified in current study, which has greatly reduced the significance and novelty of current study.

We greatly appreciate your critical observations as well as your constructive and helpful comments. We hope that we could address your questions/comments by the explanations and revisions made in the manuscript. We believe that the manuscript is substantially improved after making the suggested revisions.

Along with my some unaddressed comments, my additional comments include following:

• The introduction section is too long. It was suggested to make it concise as much as possible. Rather than addressing this comment, authors further enhance the length of introduction by adding, so many unnecessary information. It must be made better.

Response: Many thanks for this comment. The introduction section was reduced by deleting unnecessary information.

• The authors claim that English and technical writing has been improved, however from manuscript it seems that they haven’t gone through English checking by some professional English checking institute. Since there are still many sentences in the manuscript which are confusing and not written properly. I would recommend authors to address this issue.

Response: Many thanks for this comment. English writing was improved across the manuscript as you suggested. As well as, it is possible to send it to the language office in MDPI, if it is necessary after this modification.

 

• The Abbreviations section should be at the end of manuscript after Conflicts of Interest section. In addition, it should be presented in table form and include all key abbreviations and key words used in the manuscript. The authors must look into it as well.

Response: Many thanks for this comment. The abbreviation section was presented in table and moved it to the end of the manuscript after Conflicts of Interest section as you suggested.

• The abstract section needs a lot of improvement in scientific writing. There are many sentences which are not properly presented.

Response: Many thanks for this comment. The abstract section was improved in scientific writing as you suggested.

• The authors claimed that they address my comment “Add some facts and figures of surface water quality around the globe in your introduction.” In line 72 to 78. However, I didn’t find any details on facts and figures in these lines of the manuscript.

Response: Many thanks for this comment. Some facts of surface water quality were presented in the introduction section (Lines 88 to 94).

• The researchers didn’t appropriately indicate regarding changes done in manuscript. For example, I asked “Improve your location site/ map for better reading and understanding it. (Mark points and site names).” They just mentioned “We greatly appreciate your critical observations. The location map was modified for better reading and understanding as you suggested.” However, the researchers didn’t indicate page no, line no which makes reviewer very hard to follow the changes incorporated in the manuscript.

Response: Many thanks for this comment. The map was improved in Page 6 at line 219.  We modified site number to S1 to S16 on the Map. Also we wrote about the water status in different sites under section 3.1. water quality parameters.

 

The explanation of comment “You used ANN model, do share its results table and respective algorithm for better understanding in supplementary information. How you compared different parameters in it? Provide details.” is not satisfactory. The researchers are providing generic details regarding ANN model. It was recommended to add details in supplementary. Normally Visual Studio and R program is used for development of ANN model. Therefore, it was suggested to add the table as well as algorithm code in supplementary file to allow other researchers to reproduce your results and to ensure that ANN model has been properly applied to your data set.

 

Response: Many thanks for this comment. Python code to train the ANN model and select the best parameters was added in supplementary file.

• The researchers didn’t satisfactorily address this comment as well “In results, compare your answers with surface water quality standards by WHO.”

Response: Many thanks for this comment. In the results, the surface water quality was compared with WHO standards as you suggested  in Table 4 (Page 15 and line 228 to line 229).

In addition, a lot of plagiarism has been identified in current manuscript. The researchers have copied 8% of the content from research article “Using Optimized Two and Three-Band Spectral Indices and Multivariate Models to Assess Some Water Quality Indicators of Qaroun Lake in Egypt” which is again alarming and overall, 23% plagiarism has been identified in the revised manuscript. Moreover, it has been identified that similar work with same experimental design has been already done by same researchers published on 18^th September 2021 in MDPI journal “Sustainability”. Therefore, I don’t think that this study is any more suitable and novel for publishing in MDPI journal “Water”.

Response: Many thanks for this comment. The plagiarism of the first version of the manuscript was reduced to this version of the manuscript. Also, about the copied 8% of the content from research article “Using Optimized Two and Three-Band Spectral Indices and Multivariate Models to Assess Some Water Quality Indicators of Qaroun Lake in Egypt” is reduced. Therefore, there is no conflict between this manuscript and the published paper.  In this manuscript we focus with different four parameters such as total nitrogen (TN), ammonium (NH4+), orthophosphate (PO4^3-) and chemical oxygen demand (COD) to link them with different published and newly spectral indices. Also regarding the similarity of our current paper with the previously published one, here we integrated 3-D indices and artificial neural network for the detection of water quality parameters as a new method. The results showed that our research hypothesis that the ANN can be a robust tool in assessing WQPs has been proven as an effective technique. To the best of our knowledge, this protocol has given little attention and therefore for our future work we will use it for monitoring and assessing pollution indices. As well as our future work to evaluate these methods under different water quality conditions.

Author Response File: Author Response.docx

Reviewer 3 Report

I thank the authors for making a re-revision of their manuscript. While I see a significant improvement in the revised version, I'm still have some minor suggestions that can improve the readability of the manuscript for readers.

Please remove “parameters” form the title.

Tables 2 and 3: Please add the years to the table’s title.

Level of significance should be “p-value”. Please revise across the manuscript.

PO43- is “orthophosphate”. Please revise across the manuscript.

L829: Please remove “a” from “2021a”.

L829: Please remove “b” from “2021b”.

 

 

Author Response

Reviewer 3

 

I thank the authors for making a re-revision of their manuscript. While I see a significant improvement in the revised version, I'm still have some minor suggestions that can improve the readability of the manuscript for readers.

We greatly appreciate your critical observations as well as your constructive and helpful comments. We hope that we could address your questions/comments by the explanations and revisions made in the manuscript. We believe that the manuscript is substantially improved after making the suggested revisions.

Please remove “parameters” form the title.

Response: Many thanks for this comment. Parameters word was removed from the title as you suggested.

Tables 2 and 3: Please add the years to the table’s title.

Response: Many thanks for this comment. The years were added in Tables 1 and 2 as you suggested.

Level of significance should be “p-value”. Please revise across the manuscript.

Response: We greatly appreciate your critical observations. The value was changed to p-value in Tables 2 and 3 as you suggested.

PO43- is “orthophosphate”. Please revise across the manuscript.

Response: Many thanks for this comment. Phosphate (PO₄^3-) was changed to orthophosphate across the manuscript as you suggested.

L829: Please remove “a” from “2021a”.

Response: Many thanks for this comment. Reference 2021a was changed to 2021 by remove "a" as you suggested.

L829: Please remove “b” from “2021b”.

Response: Many thanks for this comment. Reference 2021b was changed to 2021 by remove "b" as you suggested.

 

Author Response File: Author Response.docx

Round 3

Reviewer 2 Report

The manuscript has been significantly improved and can now be accepted in current form.