Upstream River Erosion vis-a-vis Sediments Variability in Hugli Estuary, India: A Geospatial Approach

Round 1

Reviewer 1 Report

In this paper, geospatial techniques are used to study and analyze the Bhagirathi-Hugli River erosion patterns and accretion movements. The changes of the Bhagirathi-Hugli River bank line motion were evaluated by satellite data and remote sensing data processing and analysis methods. According to SSC Estimation, Bank line Detestion and River Bank Erosion-Accretion Assessment, it is believed that the interruption of the river is more likely to be eroded, and the accretion effect of the estuary also leads to the aggravation of the sediment load in the port. Comments on review:

1.     The introduce part first expresses accretion, then expresses erosion, and then studies erosion first, and then studies accretion, trying to keep the logical order consistent

2.     Line 227-254 The format of the table with row count is confusing

3.     Section 2.3 The link between the in-situ data and the content of the study is unclear

4.     Table 5 only expresses the trend of water area changes, and does not express the specific water area for each period. Trends can be clearly expressed by adding specific water areas or using diagrams

5.     Line 566-610 Illustrations need to be added for changes of the river in brief

6.     The study focuses on the impact of erosion on accretion in the upper reaches of the Hugli River, whether the impact of sea level rise on estuaries is concluded？

7.     The number of references is too large, please make them thin.

Author Response

Dear Reviewer,

We would like to convey our sincere thanks for giving us the opportunity to submit a revised draft of our manuscript titled “Upstream river erosion vis-a-vis sediments variability in Hugli estuary, India: a geospatial approach” to the Water. We appreciate the time and effort the reviewers have dedicated to providing valuable feedback on our manuscript. We are grateful to the reviewers for their insightful comments, which significantly improves our paper. We have tried to address all the comments and have been able to incorporate changes to reflect most of the suggestions provided by the reviewer. In response to comments from one of the reviewers, "The authors should have a professional who has remote sensing or photogrammetry background to proofread the manuscript" we added a new co-author.  Therefore, we have decided to add an author: Prof. Tuhin Ghosh, who has strong expertise in applied remote sensing. He has made specific corrections in our study and proofread it. We have highlighted the changes within the manuscript. We are sharing the Revised Version of the Manuscript, highlighted in red for clarity to identify the differences.

Best regards

Michal Habel

 

 

Response to Reviewer 1 Comments

 

Point 1.     The introduce part first expresses accretion, then expresses erosion, and then studies erosion first, and then studies accretion, trying to keep the logical order consistent

Response 1.  The introduction part has been rearranged to keep the logical order consistent.

 

Point 2.     Line 227-254 The format of the table with row count is confusing

Response 2. Table 1 has been reformated.

 

Point 3.     Section 2.3 The link between the in-situ data and the content of the study is unclear

Response 3. The in-situ data is gathered from secondary sources Pitchaikani et al. (2019). https://doi.org/10.1007/s12524-018-0884-x; from those data, an empirical formula for SSC estimation was created, which has been used for the other Landsat images to estimate the SSC for pre- and post-monsoon season. We have emphasized your question more in the manuscript's text -  see chapter 3.3.

 

Point 4.     Table 5 only expresses the trend of water area changes, and does not express the specific water area for each period. Trends can be clearly expressed by adding specific water areas or using diagrams.

Response 4. This section between lines 563-65 has been removed from the main text to eradicate ambiguity from the study. We extended this thread in Appendix A and with figures A1.a and A1.b and the description

 

Point 5.     Line 566-610 Illustrations need to be added for changes of the river in brief

Response 5. This section between lines 566-610 has been removed from the main text to eradicate ambiguity from the study. We extended this thread in Appendix A and with figures A1.a and A1.b and the description

 

Point 6.     The study focuses on the impact of erosion on accretion in the upper reaches of the Hugli River, whether the impact of sea level rise on estuaries is concluded？

Response 6. The study’s main text mentions, ’’Considering the impact of sedimentation and sea level rise on the Hugli estuary, it is reasonable to conclude that the estuary is gradually decaying due to the interplay between sedimentation and sea-level rise.” Hence the main focus of this study is on assessing the impact of upstream erosion and the influx of sediment induce by the same, which leads to intense sedimentation of the Hugli estuary. However, in conclusion, part scenario of sea-level rise has been mentioned because, despite sedimentation, the sea-level rise is also affecting the estuary, due to which certain estuarine islands have submerged (Supribhanga, Lohachara), or in the verge of submergence (Ghoramara). As the main focus is not on sea-level rise, its effect cannot be ignored, which is the reason for mentioning the impact of sea-level rise mainly in the conclusion part. Justification included in the manuscript

 

Point 7.     The number of references is too large, please make them thin.

Response 7. Several references have been removed to make the reference part thin.

 

Reviewer 2 Report

This research evaluated the erosional patterns and sediment load movement caused by natural changes and anthropogenic modifications through a variety of geospatial technologies. Specifically, an object-based image analysis (OBIA) technique namely Support Vector Machine (SVM) was used to create cluster textual indices. Results revealed that substantial erosion occurred in the last three decades with the middle stretch of the studied river. The reviewer believes that the current version of the manuscript is not yet ready for publication; the authors are encouraged to consider the following comments and suggestion and revise the manuscript accordingly.

1. The authors should streamline the Abstract section. The Abstract section should focus on explaining research importance, methodology, and conclusion. Do not include any unnecessary information but the essential information must be provided. In addition, do not use acronyms in the Abstract section.

2. The authors should consider reorganizing the manuscript to include the following sections: Introduction, Background, Methodology, Results and Discussion, and Conclusions. The Introduction section should focus on introducing the research objectives and stating the research questions that need to be answered, while the Background section should focus on reviewing of related literature and presenting the process of finding the research gap. Many key studies have been missing in literature review. One of the studies that used remote sensing technologies is “An Investigation into Remote Sensing Techniques and Field Observations to Model Hydraulic Roughness from Riparian Vegetation”. The authors should read and cite this study.

3. The authors should have a professional who has remote sensing or photogrammetry background to proofread the manuscript. There are many terms are being misused. For example, in the remote sensing field, there are four types of resolution, including spatial, spectral, radiometric, and temporal resolution. The authors should be more specific with what resolution is being referred to in the manuscript.  In addition, spatial resolution and ground sampling distance are not the same thing. The authors should read and cite the research of The Impact of Small Unmanned Airborne Platforms on Passive Optical Remote Sensing: A Conceptual Perspective. In this research, the differences between the two terms are defined.

4. The authors should include a document or appendix to explain their algorithms or equations. Such a document will assist researchers in replicating the proposed method. The authors also need to go through the equations to make sure all elements in the equations are denoted.

5. All figures and tables need to be improved. None of the figures is legible.

Author Response

Dear Reviewer,

We would like to convey our sincere thanks for giving us the opportunity to submit a revised draft of our manuscript titled “Upstream river erosion vis-a-vis sediments variability in Hugli estuary, India: a geospatial approach” to the Water. We appreciate the time and effort the reviewers have dedicated to providing valuable feedback on our manuscript. We are grateful to the reviewers for their insightful comments, which significantly improves our paper. We have tried to address all the comments and have been able to incorporate changes to reflect most of the suggestions provided by the reviewer. In response to Your comments, "The authors should have a professional who has remote sensing or photogrammetry background to proofread the manuscript", we added a new co-author. Therefore, we have decided to add an author: Prof. Tuhin Ghosh, who has strong expertise in applied remote sensing. He has made specific corrections in our study and proofread it. We have highlighted the changes within the manuscript. We are sharing the Revised Version of the Manuscript, highlighted in red for clarity to identify the differences.

Best regards

Michal Habel

 

Response to Your Comments

Point 1.     The authors should streamline the Abstract section. The Abstract section should focus on explaining research importance, methodology, and conclusion. Do not include any unnecessary information but the essential information must be provided. In addition, do not use acronyms in the Abstract section.

Response 1.  The abstract has been rewritten.

 

Point 2.   The authors should consider reorganizing the manuscript to include the following sections: Introduction, Background, Methodology, Results and Discussion, and Conclusions. The Introduction section should focus on introducing the research objectives and stating the research questions that need to be answered, while the Background section should focus on reviewing of related literature and presenting the process of finding the research gap. Many key studies have been missing in literature review. One of the studies that used remote sensing technologies is “An Investigation into Remote Sensing Techniques and Field Observations to Model Hydraulic Roughness from Riparian Vegetation”. The authors should read and cite this study.

Response 2.  The main text has been modified and reorganised into Introduction, Background, Methodology, Results and Discussion, and Conclusions.  The suggestions from the paper have been incorporated into the text.

 

Point 3.   The authors should have a professional who has remote sensing or photogrammetry background to proofread the manuscript. There are many terms are being misused. For example, in the remote sensing field, there are four types of resolution, including spatial, spectral, radiometric, and temporal resolution. The authors should be more specific with what resolution is being referred to in the manuscript.  In addition, spatial resolution and ground sampling distance are not the same thing. The authors should read and cite the research of The Impact of Small Unmanned Airborne Platforms on Passive Optical Remote Sensing: A Conceptual Perspective. In this research, the differences between the two terms are defined.

Response 3.  The terms of Remote Sensing have been changed carefully. Per the suggestion, the manuscript has been improved by one veteran Co-author Prof.Tuhin Ghosh, who has huge experience in the riverine system and geospatial technology. The suggested reference have been incorporated.

 

Point 4.   The authors should include a document or appendix to explain their algorithms or equations. Such a document will assist researchers in replicating the proposed method. The authors also need to go through the equations to make sure all elements in the equations are denoted.

Response 4.  The algorithms and equations have been separately incorporated into Appendix B of the main text with their explanations.

 

Point 5.   All figures and tables need to be improved. None of the figures is legible

Response 5.  All the figures and table figures have been rectified and clarified enough for understanding.

Reviewer 3 Report

 

I revised the original manuscript entitled ‘Upstream river erosion vis-a-vis sediments variability in Hugli estuary, India: a geospatial approach’

In my opinion, the manuscript is potentially interesting, however, some crucial parts of the manuscript should be improved in order to be accepted in this journal.

In particular:

In general, the introduction is too long and includes a geomorphological description of the study area. I want to suggest introducing in this chapter your study area, but moving the details to the study area chapter.

-row 49 delete a space

-row 90, please choose one word.

-row 129, please the comma in right

-Fig 1, is not so clear, please choose other colours to label the elements in the figure. Then specify in a legend the symbols used in the figure.

-row 165 add a space after the dot

-In fig1. Please insert the name of the cities reported in the text

-row 170 you stated ‘The upper section, which runs 96.56 km from Nadia towards Hugli, does  have an unsteady course, and traverses consistently through a vast stretch of land but  progressively alters its path.’ Please highlight the sections on the map and try to be more specific from a geomorphological point of view. Use the right terms.

-row 174 add a space

-Row 180. You stated ‘As mentioned in the last 32 years, Hugli induced land degradation to approximately 245 km2 area along its banks [32], mainly due to an imbalance between the shear stresses put on riverbank materials by the gravitational force on the downslope. This imbalance is caused by the proportion of sand (34.08%), and silt (52.4%) on the left bank, which induces riverbank failures across the year, but most significantly during the flooding season [14].’ Ok, please we need before to understand the local geological and geomorphological conditions? Which is the drainage basin of the river? Which are the fluvial landforms? (Do you have some pictures that can help the readers to understand?). Which are the slope-associated processes with high connectivity (I suppose) that interest the river system? I understand that is a regional study but some focus is necessary! Also showing changes in fluvial landforms with Google Earth.

-Please uniform in the text fig. or figure

-row 471 please delete a point after figure

-Figure 3: you stated, ‘Across the riverbank 1’. Where is riverbank 1?

-Row 573, double 2020

-Please along the manuscript specify how in situ measurements were done and where.

-Row 786, add a space

In general, the study area must be written in a clearer way including geological and geomorphological settings and how processes fluvial and/or slope-based interact with river dynamics.

For all these reasons, I suggest a MINOR revision to this manuscript.

Best regards

 

 

Author Response

Dear Reviewer, 

We add a response to your comments on a pdf file. 

Best regards 

Michał Habel

 

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

The authors have addressed all my comments.