Influence of Precipitation Conditions and Discharge Rates of River Estuary Barrages on Geomorphological Changes in an Estuarine Area

Round 1

Reviewer 1 Report

This is an interesting paper, quite well designed, showing the influence of precipitation and discharge rate of a river on geomorphological changes (bathymetry and shore line) in estuarine area. However, I think that some aspects need to be emphasized to enhance the value of this work. Therefore, I suggest some changes below:

Introduction. It is worth to emphasize the context and aim of this work, why such deatailed monitoring of topographical changes (bathymetry and shore line) in easturine area is important? I also suggest addign more references directly related to this context and to better emphasize the innovation of your work. The same in the conclusions section.

There is not a specific discussion paragraph, but I think the discussion of your results should be improved also compairing them to other studies in literature conducted in the same area and with the same aim, in order to underline the strength of your work.

Thanks.

Author Response

Comments and Suggestions for Authors

 

This is an interesting paper, quite well designed, showing the influence of precipitation and discharge rate of a river on geomorphological changes (bathymetry and shore line) in estuarine area. However, I think that some aspects need to be emphasized to enhance the value of this work. Therefore, I suggest some changes below:

Introduction. It is worth to emphasize the context and aim of this work, why such deatailed monitoring of topographical changes (bathymetry and shore line) in easturine area is important? I also suggest addign more references directly related to this context and to better emphasize the innovation of your work. The same in the conclusions section.

There is not a specific discussion paragraph, but I think the discussion of your results should be improved also compairing them to other studies in literature conducted in the same area and with the same aim, in order to underline the strength of your work.

Thanks.

 

Reply:

This research area is reclaimed by various human activities, including reclamation, and environmental changes are intensifying. However, the estuary area is an important environmental and ecological area, such as migratory birds and mudflats. And past studies have focused on monitoring changes. In this study, we discussed monitoring changes due to causes.

Therefore, we revised the introduction and conclusion according to the reviewer's suggestion.

Thank you.

Author Response File: Author Response.docx

Reviewer 2 Report

Dear Authors,

Your article is interesting. I found no errors in the text. You've done good research. congratulations. One thing - add sources under the figures. best regards Reviewer

 

 

No comments.

Author Response

Comments and Suggestions for Authors

 

Your article is interesting. I found no errors in the text. You've done good research. congratulations. One thing - add sources under the figures. best regards Reviewer

 

 

Reply:

We added the source of the figure according to the reviewer's suggestion.

Thank you.

 

Author Response File: Author Response.docx

Reviewer 3 Report

The results of the study presented in the manuscript are of both scientific and applied interest. Further development in this area of research and monitoring of erosion and sedimentation processes in the studied water area can contribute to obtaining new interesting findings. I have only a few small recommendations.

1. It is necessary to more clearly state the novelty of your research.

2. What are the limitations of the study? These restrictions should be written in the Discussion section.

3. It is advisable to write about the prospects for your further research in this area.

4. The subfigures of Figure 8 are visually difficult to compare with each other. Please think of a different way to better show the dynamics of change.

5. Legend of Figure 4 is hard to read.

English needs some improvement.

Author Response

Comments and Suggestions for Authors

 

The results of the study presented in the manuscript are of both scientific and applied interest. Further development in this area of research and monitoring of erosion and sedimentation processes in the studied water area can contribute to obtaining new interesting findings. I have only a few small recommendations.

1. It is necessary to more clearly state the novelty of your research.

Reply:

We added the contents according to the reviewer's suggestion.

Thank you.

 

2. What are the limitations of the study? These restrictions should be written in the Discussion section.

Reply:

The limitation of conducting this study is that the area is being reclaimed by various human activities, including reclamation, and environmental changes are intensifying. The estuary area is an important environmental and ecological area, such as migratory birds and mudflats. However, it is a situation that is constantly being destroyed and changed, so the results of the study should be shared and known.

Following the reviewer's suggestion, we added the contents to the introduction and conclusion.

Thank you.

 

3. It is advisable to write about the prospects for your further research in this area.

Reply:

We added the contents according to the reviewer's suggestion.

Thank you.

 

4. The subfigures of Figure 8 are visually difficult to compare with each other. Please think of a different way to better show the dynamics of change.

Reply:

We revised the figure according to the suggestion.

Thank you.

 

5. Legend of Figure 4 is hard to read.

Reply:

We expressed ColorBar in large volume according to the reviewer's suggestion.

Thank you.

 

Author Response File: Author Response.docx

Reviewer 4 Report

The objective of this paper is quite interesting. The authors evaluated changes in shoreline and undersea topography in the Nakdong River estuary using depth and shoreline surveys of the estuary, as well as data on discharge, suspended sediments, and precipitation over basin. They claim that it is not possible to unilateral trend among the variables. The study is interesting and well conducted, but I have comments and recommendations to address to the authors

1)      They considering data from 2018 to 2022 (5 Years period). Needed justification for the following:

Why the authors chosen for this short period evaluation? Any specific reason for choosing this period.

2)      Limitations of study needs to discussed.

3)      In Figure 8. Changes in the shoreline owing to typhoons. This Shoreline changes due to typhoons or high and low tides difference?? What is the significance of these lines? What are the takeaway points from these lines? Needed clear discussion.

4)      Line 238-239 “As shown in Figure 9, in October 2020, it was confirmed that Shoreline 2

was interrupted and a channel was formed. In Title of Figure 9. Shoreline surveying using GPS (Oct. 2018–Oct. 2022). How the authors confirmed that Shoreline 2  from Fig 9??

5)      Line 244-245  “…sediment deposition occurred every year, leading to an increase in the height of the shoreline.” And Line 246-247 “….Shorelines 1 and 2 showed decreasing trends in height…” why this contradictory result?

6)      What are the takeaway points from Figure 10?

7)      Line 292 – 294 “ The results in Figure 5 show a general trend that as the discharge increases, the suspended sediment discharge also increases” Is it from Figure 5? Check this

8)      Many contradictory discussions throughout the paper. Find difficult to readers and needs better clarity on this.

Eg. Line 290-292 “ This result may be considered to be obvious given that increased precipitation leads to increased inflow to the Nakdong River, and the increased  water flow can naturally explain the increase in the sediment discharge.” Contradictory with 299-300  “However, it was found that the suspended sediment discharge did not increase in proportion to the discharge”

 

Author Response

Comments and Suggestions for Authors

 

The objective of this paper is quite interesting. The authors evaluated changes in shoreline and undersea topography in the Nakdong River estuary using depth and shoreline surveys of the estuary, as well as data on discharge, suspended sediments, and precipitation over basin. They claim that it is not possible to unilateral trend among the variables. The study is interesting and well conducted, but I have comments and recommendations to address to the authors

1)      They considering data from 2018 to 2022 (5 Years period). Needed justification for the following:

Why the authors chosen for this short period evaluation? Any specific reason for choosing this period.

Reply:

The reason for analyzing the data over the past five years is to emphasize the change in topography due to the effects of torrential rains and typhoons in 2020. Such content was explained in the manuscript.

Thank you.

 

2)      Limitations of study needs to discussed.

Reply:

The limitation of conducting this study is that the area is being reclaimed by various human activities, including reclamation, and environmental changes are intensifying. The estuary area is an important environmental and ecological area, such as migratory birds and mudflats. However, it is a situation that is constantly being destroyed and changed, so the results of the study should be shared and known. And I explained it in the manuscript.

Thank you.

 

3)      In Figure 8. Changes in the shoreline owing to typhoons. This Shoreline changes due to typhoons or high and low tides difference?? What is the significance of these lines? What are the takeaway points from these lines? Needed clear discussion.

Reply:

It is important that changes in the coastline have also occurred due to typhoons. Because changes occur due to low tide and high tide, the coastline was acquired at low tide and high tide, respectively. In addition, as mentioned in the study, it was confirmed through the coastline survey that the coastline was cut off in the middle due to the typhoon, and it was also confirmed that a new flow of water occurred. Added description to manuscript.

Thank you.

 

4)      Line 238-239 “As shown in Figure 9, in October 2020, it was confirmed that Shoreline 2

was interrupted and a channel was formed. In Title of Figure 9. Shoreline surveying using GPS (Oct. 2018–Oct. 2022). How the authors confirmed that Shoreline 2  from Fig 9??

Reply:

Since 2018, data using GPS has been acquired, and the coastline has been compared using data obtained using GPS, and as a result, the erosion section has been confirmed.

We revised the text according to the reviewer's suggestion.

Thank you.

 

5)      Line 244-245  “…sediment deposition occurred every year, leading to an increase in the height of the shoreline.” And Line 246-247 “….Shorelines 1 and 2 showed decreasing trends in height…” why this contradictory result?

Reply:

In the case of this part, as the discharge volume increases, a lot of sediment is discharged from the land, and the sediment is increased accordingly.

We revised the text according to the reviewer's suggestion.

Thank you.

 

6)      What are the takeaway points from Figure 10?

Reply:

A graph of the height values of the coastline shows the deviation from the low to the high point. This represents the height value by time of data acquisition to determine whether sedimentation or erosion occurred at that time.

We revised the text according to the reviewer's suggestion.

Thank you.

 

7)      Line 292 – 294 “ The results in Figure 5 show a general trend that as the discharge increases, the suspended sediment discharge also increases” Is it from Figure 5? Check this

Reply:

I'm sorry.

This is Figure 11, not Figure 5.

Thank you for your in-depth review.

 

8)      Many contradictory discussions throughout the paper. Find difficult to readers and needs better clarity on this.

Eg. Line 290-292 “ This result may be considered to be obvious given that increased precipitation leads to increased inflow to the Nakdong River, and the increased  water flow can naturally explain the increase in the sediment discharge.” Contradictory with 299-300  “However, it was found that the suspended sediment discharge did not increase in proportion to the discharge”

Reply:

You can definitely think that way.

In general, as the discharge from the estuary increases, the estuary tends to be deposited by the sediments of the incubation base. However, if the discharge from the estuary bank increases rapidly and pushes it into the estuary with strong force, erosion is confirmed in some areas. Therefore, it may seem contradictory enough, but I think it is a special case in the second half of 2020.

Such an explanation was added to the text.

We think readers will be fully understood.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

I appreciated the effort of the authors in addressing my comments. I think that the paper is now clearer and can be published.