Living Shoreline: Preliminary Observations on Nature-Based Solution for Toe-Line Protection of Estuarine Embankments and Mangrove Regeneration

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The peer-reviewed manuscript «Living Shores: Preliminary observations on a natural solution to protect the toe line of estuarine embankments and mangrove regeneration» by P. Chatterjee et al., presents the results of an experiment to protect the toe line of estuarine embankments from frequent slope failures using silt fences.

This study is of considerable scientific and practical interest, both for the region where the research was carried out (Sundarbans Biosphere Reserve) and for regions with similar ecological problems. The manuscript will be of interest to both specialist and general readers. The manuscript is in line with the theme of Sustainability.

The manuscript is written in excellent scientific language, all parts of the manuscript are structured, well coordinated and form a coherent, understandable and scientifically interesting work. The authors have done an impressive job, both practically and analytically. The conclusions are fully supported by the research results. The manuscript has a sufficient number of relevant references and good illustrative material. As a minor comment, I would like to recommend the improvement (resolution/font size) of Figure 3.

In my opinion, the manuscript can be published in its present form.

Author Response

Comment 1: I would like to recommend the improvement (resolution/font size) of Figure 3

Response 1: We agree. Figure 3 has been modified

Reviewer 2 Report

Comments and Suggestions for Authors

This study presents a timely and innovative investigation into the application of nature-based solutions (NbS) for coastal protection in the vulnerable Sundarbans region. The use of terracotta silt traps as a "Living Shoreline" strategy demonstrates both ecological and socio-economic relevance, particularly in addressing the dual challenges of embankment erosion and mangrove degradation. The manuscript is well-structured, and the methodology is clearly described. However, several areas require clarification and expansion to strengthen the scientific rigor and broader applicability of the findings.

1. The observation period (16 months) is insufficient to conclusively validate the long-term efficacy of the intervention, especially given the dynamic hydro-sedimentary processes in estuarine environments. The authors should explicitly acknowledge this limitation and propose a roadmap for extended monitoring, particularly to assess resilience against cyclones and multi-year tidal variability.
2. While the dominance of sand/clay in different estuarine zones is noted, the manuscript lacks a mechanistic explanation for these patterns. For instance, how do tidal energy, river discharge, and trap design interact to influence sediment retention? Incorporating hydrodynamic modeling or comparative sediment flux data could enhance interpretability.
3. The reported mangrove regeneration is promising but needs deeper ecological context. For example:

What is the survival rate of saplings beyond the study period?

How do the regenerated mangroves compare to natural stands in terms of biodiversity and ecosystem services (e.g., carbon sequestration)?

Including quantitative metrics (e.g., stem density, biomass) would strengthen the ecological narrative.

Author Response

Comment 1: The observation period (16 months) is insufficient to conclusively validate the long-term efficacy of the intervention, especially given the dynamic hydro-sedimentary processes in estuarine environments.

Response 1: The limitation is already stated in line 349-351

Comment 2: The authors should explicitly acknowledge this limitation and propose a roadmap for extended monitoring, particularly to assess resilience against cyclones and multi-year tidal variability.

Response 2: We agree. Modifications added in Line 351-353

Comment 3: While the dominance of sand/clay in different estuarine zones is noted, the manuscript lacks a mechanistic explanation for these patterns.

Response 3: We agree. Modifications are added in Line 239-244

Comment 4: How do tidal energy, river discharge, and trap design interact to influence sediment retention? Incorporating hydrodynamic modeling or comparative sediment flux data could enhance interpretability.

Response 4: This is beyond the ambit of current study. 

Comment 5: The reported mangrove regeneration is promising but needs deeper ecological context. For example: What is the survival rate of saplings beyond the study period?

Response 5: We agree. Modifications added in Line 253-261

Comment 6: How do the regenerated mangroves compare to natural stands?

Response 6: We agree. Modifications are added in Line no 154-155

Comment 7: In terms of biodiversity and ecosystem services (e.g., carbon sequestration)? Including quantitative metrics (e.g., stem density, biomass) would strengthen the ecological narrative.

Response 7: Comparing ecosystem services with natural stands is premature and outside the scope of this study.

Reviewer 3 Report

Comments and Suggestions for Authors

This thesis investigates the use of natural eco-coastal methods to promote mangrove restoration and protect estuarine embankments by constructing silt traps through terra cotta rings. The study area was the Sundarbans Biosphere Reserve in India and the experiment lasted for 16 months. The paper's research is relevant and proposes a low-cost ecological restoration strategy, especially in the context of climate change and sea level rise. However, there is still room for improvement in terms of language expression, method description, data analysis, and academic standardization, as suggested below.

1. There are some problems with the language, as some of the sentences are long and redundant, which affects readability.
2. The description of the method of sediment data collection is rather brief. It is recommended that details be provided on how sediment height is measured? Are scales or laser scans used?
3. Data visualization is not clear enough. Recommendation: Use line graphs to show recovery trends for different species.
4. The explanation for oyster attachment is inadequate: is it due to slowing of the water flow? Is it due to the chemical composition of the clay ring that favors oyster attachment?
5. Unharmonized formatting of some references.
6. It is recommended that future studies be added to discuss the need for long-term monitoring and the potential impact of clay rings.
7. These articles may be helpful in improving the quality of the manuscript, please check them out:

https://doi.org/10.1680/jgein.24.00143

https://doi.org/10.1016/j.conbuildmat.2023.134465

Author Response

Comment 1: There are some problems with the language, as some of the sentences are long and redundant, which affects readability.

Response 1: Text has been revised

Comment 2: The description of the method of sediment data collection is rather brief. It is recommended that details be provided on how sediment height is measured? Are scales or laser scans used?

Response 2: Modification in Line 141-143

Comment 3: Data visualization is not clear enough. Recommendation: Use line graphs to show recovery trends for different species.

Response 3: Not relevant

Comment 4: The explanation for oyster attachment is inadequate: is it due to slowing of the water flow? Is it due to the chemical composition of the clay ring that favors oyster attachment?

Response 4: Modification in Line 267-272

Comment 5: Unharmonized formatting of some references.

Response 5: Addressed

Comment 6: It is recommended that future studies be added to discuss the need for long-term monitoring and the potential impact of clay rings.

Response 6: Our study has limited objective and we are committed to monitor only these two objectives in future. Refer line 94-95

Comment 7: These articles may be helpful in improving the quality of the manuscript, please check them out:

https://doi.org/10.1680/jgein.24.00143

https://doi.org/10.1016/j.conbuildmat.2023.134465

Response 7: Noted

Reviewer 4 Report

Comments and Suggestions for Authors

See attached file.

This study focuses on Nature-based solution for toe-line protection of estuarine embankments and mangrove regeneration. The authors discuss the e results of an experiment in toe-line protection of estuarine embankments from frequent slope failure using silt traps. They tested the feasibility of terracotta rings to trap silt and promote natural mangrove regeneration in barren patches in front of embankments around human settlements in the Indian Sundarbans region, designated as Sundarban Biosphere Reserve. This work is worth publishing after modified. My comments are as follows:

1. Why is this study novel? Please point out that this study is not a case study in introduction.
2. Please add a literature review about toe-line protection.
3. Section of Intervention Design. Is there a comparative experiment?
4. Section of Monitoring of sediment depostion. Add more sediment information in the silt traps. Is it same as the sediment properties at the testing point?
5. Section of Net sediment accumulation over 12 months. How did these results come about? The average value?
6. Line 192-193. How do you determine the sediment composition?
7. Conclusions. Rewrite this part. Please highlight your main found and couclusions.
8. References. Formatting standards.

Comments for author File: Comments.pdf

Comments on the Quality of English Language

Good.

Author Response

Comment 1: Why is this study novel? Please point out that this study is not a case study in introduction.

Response 1: This is the first study which has adopted nature inspired solutions and implemented the same in the highly dynamic Sundarbans mangrove ecosystem influenced by freshwater, tidal inundations and erosion. The silt trap approach is cheap, cost-effective and sustainable strategy for toe-line embankment protection in Sundarbans and wider coastal oceans across South Asia.

Comment 2: Please add a literature review about toe-line protection.

Response 2: Added as citation number 42 and 43

Comment 3: Section of Intervention Design. Is there a comparative experiment?

Response 3: Yes. These have been referred to in Line 85-87

Comment 4: Section of Monitoring of sediment deposition. Add more sediment information in the silt traps. Is it same as the sediment properties at the testing point?

Response 4: Seasonal monitoring of sediment granulometry was undertaken near the site and away from the site. The granulometric patterns were consistent as observed in the silt trap. See Line 150-152 and 198-199

Comment 5: Section of Net sediment accumulation over 12 months. How did these results come about? The average value?

Response 5: See Line 145-148

Comment 6: How do you determine the sediment composition?

Response 6: Granulometric analysis following Chauhan et al ,2014. Line no -148-149

Comment 7: Conclusions. Rewrite this part. Please highlight your main found and conclusions.

Response 7: As advised, the section has been rewritten

Comment 8: References. Formatting standards.

Response 8: Addressed

Reviewer 5 Report

Comments and Suggestions for Authors

All in the MS

Comments for author File: Comments.pdf

Author Response

Comment 1: must add in the Abstract: Nature-based solution...

Response 1: We agree. Added

Comment 2: Ethis aspects: Add

Response 2: No ethical issues. Humans and animals not involved. All requisite permissions from state agencies were sought and granted

Comment 3: add information specific to Table, location, periods? (Table 2)

Response 3: Added

Comment 4: +/- standard deviation

Response 4: Added

Comment 5: Why lines connected between evaluation points? (Figure 3)

Response 5: We agree. Figure 3 changed

Comment 6: add more information locations, periods evaluated, etc.? (Figure 3)

Response 6: Required information is in the legend of Figure 3

Comment 7: add more information (Figure 4)

Response 7: Nothing to add

Comment 8: add more information (Figure 5)

Response 8: Nothing to add

Author Response File: Author Response.docx