Experimental Assessment of Vegetation Density and Orientation Effects on Flood-Induced Pressure Forces and Structural Accelerations

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript, in its current form, cannot be accepted for publication. Major sections, including the abstract, methodology, results, and figures, contain numerous inconsistencies, unsupported claims, ambiguous data, and mismatched citations. Experimental details such as vegetation diameters, spacing, and orientations are contradictory, while key results are either speculative or not clearly supported by the presented figures. Figures 3.3–3.7 require correction, and statistical analyses must be clarified and accurately referenced. Additionally, the manuscript exhibits widespread issues in notation, units, reference style, and terminology (e.g., inconsistent use of “tree” versus “vegetation”). A thorough revision and proofreading of the entire manuscript are necessary to ensure clarity, accuracy, and scientific rigor before it can be considered for review.
Please see the attached highlighted PDF for further corrections.

Major comments:

1) The abstract section is completely vague and should be rewritten. For example:

a) Lines 34-36 are ambiguous because it does not specify what is being reduced and by how much. Acceleration of what? In the context of your study (flow through a porous vegetation patch), the “acceleration” most likely refers to flow acceleration downstream of the vegetation or the longitudinal acceleration of fluid parcels caused by blockage effects. To avoid confusion, it’s better to specify: “flow acceleration in the streamwise direction”, or “local acceleration of water velocity downstream of the patch.”

1. What percentage of hydrostatic pressure reduction? Instead of “most significant reduction,” you should report the actual value from your results. Without inserting those numbers, the sentence remains vague.
2. Lines 38-40: As it stands, the sentence just says “variation exists” without explaining what that means physically. You can make it sharper by connecting the statistics (mean, standard deviation, range) to the flow physics.

2) The citation is mismatched. Your sentence:

“Over the past few decades, Asian and European countries have experienced catastrophic floods and tsunamis, resulting in extensive damage to buildings and loss of human life [3].” Lines 53-54.

But Reference (3) that you quoted is about energy history and Japan’s nuclear energy crisis, not about hydro-meteorological hazards or tsunamis. That source cannot credibly support your statement about floods and tsunamis in Asia and Europe.

3) Lines 57-62: paragraph currently lacks citations, which is essential for credibility, especially when referencing varied methodological approaches. Please cite some recent and most appropriate studies justifying the statement made.

4) Lines 66-74: The first sentence about “devastating floods… rapid inundation of entire floodplains following embankment failures” is not supported by [6] or [7]. Those are experimental hydraulics papers, not disaster case studies.
There is a mismatch again between what the text claims and what the cited articles demonstrate. Revise the sentence to match the actual references.

5) Lines 104-105: This paragraph is clear in intent, but it can include research gaps, contributions, and objectives that will stand out more strongly from the readers´ perspective.

6) Section 2.2, paragraph 1, Lines 130-149: This paragraph contains a clear inconsistency. Issues:

1. a) Line 130–131: “…trunk diameter ranging from 0.1 to 0.33 centimetres …” That’s 1–3.3 mm, which is way too small for a eucalyptus tree trunk of 7.6–14.6 m length.
2. Line 138–139: “…the 3 cm diameter metal rods are used to represent model trees at a 1:100 scale …”. At a 1:100 scale, a 3 cm rod represents a 300 cm (3 m) trunk diameter. That matches mature eucalyptus much better.

I would suggest that the authors consider directly stating that steel dowels are used. It is now a usual practice among researchers to use a cylindrical body to mimic solid vegetation.

7) The inconsistency in experimental data is making the review quite difficult. For example, authors have stated in:

Lines 133-134: Flow properties were observed using vegetation elements in the form of 0.3 cm diameter steel cylinders.

Lines 139-140: In this experimental study, the 3 cm diameter metal rods are used to represent model trees at a 1:100 scale [7].

Lines 156-157: "d" is the diameter of the model tree (herein represented by a cylindrical dowel of 0.3 cm in diameter).

Please proofread and make sure there is no ambiguity among the experimental data provided.

8) In Figure 2.2(a), the gap between two cylinders is denoted as D, whereas in lines 153–157, G is used to denote the spacing between two neighbouring cylinders. These should be made consistent. Ensure that figure labels, captions, abbreviations, and units are uniform throughout the manuscript.

9) In Figure 2.2(a), what is Vw? And how the value of 3, which should be 3, was decided for the distance between two cylinders?

10) The statements in lines 200–206 present conclusions regarding hydrostatic pressure, fluid forces, and the effect of vegetation arrangements without any prior presentation of results or supporting data. These claims are currently unsubstantiated in the manuscript. To maintain scientific rigor, either (i) remove these statements, or (ii) explicitly reference the figures, tables, or experimental data from which these conclusions are drawn. Without such evidence, the statements risk being perceived as speculative rather than results-based.

11) What is the difference between Figure 3.3(a) and (b)? Both depict intermediate vegetation with different orientations and the same dn = 180. However, the results differ. In Figure 3.3(a), the no-vegetation case and I30180 show nearly the same pressure versus Froude number, but this is not the case in Figure 3.3(b), despite the condition being the same.

12) Figure 3.3 is not correct. Correct them. There are ambiguous results represented in figure 3.3.

13) Rewrite the result section again with a proofread, since many of the results are depicted wrong and are speculative. For example:
(a) Figure 3.4 shows the effect of G/d, i.e., sparse versus intermediate spacing. The authors state, and I quote, “Figure 3.4(a, b, c, d) illustrates that reducing the spacing within the vegetation leads to decreased acceleration.” However, in Figure 3.4(a–b), both the intermediate (I) and sparse (S) cases for different orientations and dn values have coinciding points on the graph. How, then, can the above statement be considered accurate?

(b) Similarly, it can be stated for Figure 3.5 (a-d).

14) I would like to suggest that authors should improve lines 240-260 by:

(a) Including figures or tables showing the acceleration reduction for each orientation and patch density.

(b) Clarifying how much the difference between 22.1% and 21.8% matters in practical terms.

(c) Avoiding broad causal statements (perpendicular vegetation provides greater hydraulic resistance) without explicit support from experimental results or literature. See lines 256-260.

15) Remove lines 274–281 and Figure 3.7, as the paragraph is repetitive and does not present any significant results from the time-series data. Using a Fast Fourier Transform (FFT), a time-domain acceleration signal can be decomposed into its constituent frequencies, revealing the dominant vibration frequencies and their amplitudes in the frequency domain.

16) Section 3.4, Lines 306-323: The paragraph mixes general background statements, literature references, and study results, making it somewhat repetitive and unfocused. Some statements (e.g., lines 306–309) summarize well-known concepts rather than presenting new findings. Consider tightening the text by clearly separating background, methodology, and results, and focus on observations directly supported by your figures and statistical analysis.

 

Minor:

• Inconsistency in figure numbering. Please correct them.
• Inconsistent reference style. Correct them.
• Line 182: The Froude number was not previously denoted as “Fro.” Please ensure consistent notation throughout the manuscript for better readability. Additionally, provide all abbreviations or nomenclature at their first occurrence for clarity.
• The terms “tree” and “vegetation” are currently used interchangeably in the manuscript. It is recommended to use “vegetation” consistently throughout for clarity and uniformity. For example, see line 184.
• Lines 211-212: Fro?
• Line 266, 268: Inconsistent decimal system.
• To many inconsistencies in the notations. It is difficult to interpret the results under this condition. See line 391, B/d = 1.09 should be G/d? Please correct them.
• Lines 401-402: Incomplete sentence.

 

Comments for author File: Comments.pdf

Author Response

Subject: Submission of Revised Manuscript: ID Water 3871360

Dear Editor,

"We are appreciative of the reviewers' detailed feedback, which has helped us to substantially strengthen the arguments and clarity of the manuscript. We have provided a point-by-point response to all comments from the reviewers below. All changes in the manuscript have been highlighted in red for the editors' and reviewers' convenience”.

We look forward to hearing from you.

Sincerely,

Dr. Afzal Ahmed and Dr. Manousos Valyrakis and Co-authors

 

Major comments:

• The abstract section is completely vague and should be rewritten. For example:

Response: The abstract has been rewritten in the revised manuscript

a) Lines 34-36 are ambiguous because it does not specify what is being reduced and by how much. Acceleration of what? In the context of your study (flow through a porous vegetation patch), the “acceleration” most likely refers to flow acceleration downstream of the vegetation or the longitudinal acceleration of fluid parcels caused by blockage effects. To avoid confusion, it’s better to specify: “flow acceleration in the streamwise direction”, or “local acceleration of water velocity downstream of the patch.”

1. What percentage of hydrostatic pressure reduction? Instead of “most significant reduction,” you should report the actual value from your results. Without inserting those numbers, the sentence remains vague.
2. Lines 38-40: As it stands, the sentence just says “variation exists” without explaining what that means physically. You can make it sharper by connecting the statistics (mean, standard deviation, range) to the flow physics.

Response: The confusing lines and statements are revised and point 1 and 2 are incorporated in the revised abstract.

2) The citation is mismatched. Your sentence:

“Over the past few decades, Asian and European countries have experienced catastrophic floods and tsunamis, resulting in extensive damage to buildings and loss of human life [3].” Lines 53-54.

But Reference (3) that you quoted is about energy history and Japan’s nuclear energy crisis, not about hydro-meteorological hazards or tsunamis. That source cannot credibly support your statement about floods and tsunamis in Asia and Europe.

Response: The reference [3] has been updated in the revised manuscript

• Lines 57-62: paragraph currently lacks citations, which is essential for credibility, especially when referencing varied methodological approaches. Please cite some recent and most appropriate studies justifying the statement made.

Response: The author has cited two references within line 57-62 in the revised manuscript.

• Lines 66-74: The first sentence about “devastating floods… rapid inundation of entire floodplains following embankment failures” is not supported by [6] or [7]. Those are experimental hydraulics papers, not disaster case studies.
  There is a mismatch again between what the text claims and what the cited articles demonstrate. Revise the sentence to match the actual references.

Response: The mentioned sentences are revised in the revised manuscript.

• Lines 104-105: This paragraph is clear in intent, but it can include research gaps, contributions, and objectives that will stand out more strongly from the readers´ perspective.

Response: The mentioned paragraph has been revised and now it includes research gaps, contributions, and objectives as mentioned by the reviewer

6) Section 2.2, paragraph 1, Lines 130-149: This paragraph contains a clear inconsistency. Issues:

1. a) Line 130–131: “…trunk diameter ranging from 0.1 to 0.33 centimetres …” That’s 1–3.3 mm, which is way too small for a eucalyptus tree trunk of 7.6–14.6 m length.
2. Line 138–139: “…the 3 cm diameter metal rods are used to represent model trees at a 1:100 scale …”. At a 1:100 scale, a 3 cm rod represents a 300 cm (3 m) trunk diameter. That matches mature eucalyptus much better.

I would suggest that the authors consider directly stating that steel dowels are used. It is now a usual practice among researchers to use a cylindrical body to mimic solid vegetation.

Response: The reviewer’s observations are acknowledged and incorporated in the revised manuscript in the mentioned paragraph under section 2.2.

7) The inconsistency in experimental data is making the review quite difficult. For example, authors have stated in:

Lines 133-134: Flow properties were observed using vegetation elements in the form of 0.3 cm diameter steel cylinders.

Lines 139-140: In this experimental study, the 3 cm diameter metal rods are used to represent model trees at a 1:100 scale [7].

Lines 156-157: "d" is the diameter of the model tree (herein represented by a cylindrical dowel of 0.3 cm in diameter).

Please proofread and make sure there is no ambiguity among the experimental data provided.

Response: The author has made corrections in the mentioned paragraphs/lines. Now the revised paragraph is clearer for the reader having no ambiguity.

8) In Figure 2.2(a), the gap between two cylinders is denoted as D, whereas in lines 153–157, G is used to denote the spacing between two neighbouring cylinders. These should be made consistent. Ensure that figure labels, captions, abbreviations, and units are uniform throughout the manuscript.

Response: The authors have made the notations clear and uniform in the revised manuscript.

9) In Figure 2.2(a), what is Vw? And how the value of 3, which should be 3, was decided for the distance between two cylinders?

Response: Figure 2.2 (a) has now been modified and the notations are clear and also explained in the text in the revised manuscript. The value of the spacing was decided upon empirical observations in the field – these also return values of density that are representative of the sparce and intermittent vegetation density patches.

10) The statements in lines 200–206 present conclusions regarding hydrostatic pressure, fluid forces, and the effect of vegetation arrangements without any prior presentation of results or supporting data. These claims are currently unsubstantiated in the manuscript. To maintain scientific rigor, either (i) remove these statements, or (ii) explicitly reference the figures, tables, or experimental data from which these conclusions are drawn. Without such evidence, the statements risk being perceived as speculative rather than results-based.

Response: The authors agreed with the reviewer’s observation. The mentioned sentences are removed in the revised manuscript.

11) What is the difference between Figure 3.3(a) and (b)? Both depict intermediate vegetation with different orientations and the same dn = 180. However, the results differ. In Figure 3.3(a), the no-vegetation case and I30180 show nearly the same pressure versus Froude number, but this is not the case in Figure 3.3(b), despite the condition being the same.

Response: Figure 3.3 a,b are rechecked and corrected in the revised manuscript.

 

12) Figure 3.3 is not correct. Correct them. There are ambiguous results represented in figure 3.3.

Response: Figure 3.3 revised and corrected in the revised manuscript.

 

13) Rewrite the result section again with a proofread, since many of the results are depicted wrong and are speculative. For example:

Response: Most of the part of Result section has been revised.

(a) Figure 3.4 shows the effect of G/d, i.e., sparse versus intermediate spacing. The authors state, and I quote, “Figure 3.4(a, b, c, d) illustrates that reducing the spacing within the vegetation leads to decreased acceleration.” However, in Figure 3.4(a–b), both the intermediate (I) and sparse (S) cases for different orientations and dn values have coinciding points on the graph. How, then, can the above statement be considered accurate?

Response: As per the reviewer’s observation and suggestion, Figure 3.4 has been replaced with Figure 3.5 and Figure 3.4 is presented for better understanding of the results. Figure 3.5 shows the bar chart which is now better for understanding for the reader.

 

Response:

(b) Similarly, it can be stated for Figure 3.5 (a-d).

14) I would like to suggest that authors should improve lines 240-260 by:

(a) Including figures or tables showing the acceleration reduction for each orientation and patch density.

(b) Clarifying how much the difference between 22.1% and 21.8% matters in practical terms.

Response: The author has mentioned that “the sparse vegetation configuration, the average percentage reduction in the physical model structure acceleration due to the presence of the vegetation array was 21.8%. Although there is a small percentage difference between intermediate and sparse vegetation, it suggests that even sparse vegetation arrays offer substantial protective utility, which is highly significant for cost-effective risk reduction strategies where resources or space are constrained”. The same paragraph is incorporated in the revised manuscript.

 

(c) Avoiding broad causal statements (perpendicular vegetation provides greater hydraulic resistance) without explicit support from experimental results or literature. See lines 256-260.

Response: The comment of the reviewer has been incorporated in the revised manuscript.

15) Remove lines 274–281 and Figure 3.7, as the paragraph is repetitive and does not present any significant results from the time-series data. Using a Fast Fourier Transform (FFT), a time-domain acceleration signal can be decomposed into its constituent frequencies, revealing the dominant vibration frequencies and their amplitudes in the frequency domain.

Response: The suggested lines and Figure 3.7 have been removed in the revised manuscript.

16) Section 3.4, Lines 306-323: The paragraph mixes general background statements, literature references, and study results, making it somewhat repetitive and unfocused. Some statements (e.g., lines 306–309) summarize well-known concepts rather than presenting new findings. Consider tightening the text by clearly separating background, methodology, and results, and focus on observations directly supported by your figures and statistical analysis.

Response: Lines 306-323 have been rewritten in the revised manuscript

 

Minor:

• Inconsistency in figure numbering. Please correct them.

Response: The numbering is now corrected

• Inconsistent reference style. Correct them.

Response: Reference style is corrected and now it is consistent in the revised form

• Line 182: The Froude number was not previously denoted as “Fro.” Please ensure consistent notation throughout the manuscript for better readability. Additionally, provide all abbreviations or nomenclature at their first occurrence for clarity.

Response: The notations have been corrected and now all of these are consistent.

• The terms “tree” and “vegetation” are currently used interchangeably in the manuscript. It is recommended to use “vegetation” consistently throughout for clarity and uniformity. For example, see line 184.

 

Response: Now the term “Vegetation” has been replaced where it is mentioned by the reviewer.

• Lines 211-212: Fro?

Response: Fro is replaced with the word Froude number

• Line 266, 268: Inconsistent decimal system.

Response: The correction has been made

• To many inconsistencies in the notations. It is difficult to interpret the results under this condition. See line 391, B/d = 1.09 should be G/d? Please correct them.

Response: B/d has been replaced with G/d in the mentioned place.

• Lines 401-402: Incomplete sentence.

Response: The correction has been made at the mentioned point

Reviewer 2 Report

Comments and Suggestions for Authors

1- The first three sentences of the abstract are general and should be removed from the abstract.
2- What was the effect of acceleration on the rate of increase in water depth and hydrostatic pressure.
3- Is the aim of the present study to control floods using vegetation?
If the answer is yes, please state the effect of the angle of vegetation on the rate of increase in depth and hydrostatic pressure?
4- How is the effect of increasing the Froude number and the angle of plant placement on the rate of energy consumption evaluated?
5- Unfortunately, the article is not in journal format, please correct it.
6- Correct Figure 1 and also specify the lengths on the schematic figure.
7- Why has the Froude number of supercritical flow not been investigated? Isn't it true that in natural flows, only subcritical flow is formed during floods?
8- Please enrich the hydraulic analyses.
9- The changes in the Froude number investigated are very small and within a certain range, even these changes can be ignored. It is recommended that the Froude number range be checked to at least 0.8?

Comments on the Quality of English Language

I don't think there is any particular problem with the language.

Author Response

Dear Reviewer,

Thank you for your insightful comments, which have further improved the clarity, focus, and scientific depth of our manuscript. Below, we provide a point-by-point response to each suggestion, detailing how we have addressed it in the revised manuscript. All changes are highlighted for ease of review.

1. The first three sentences of the abstract are general and should be removed from the abstract. Response: We agree that the initial sentences provide broad context better suited to the introduction. These have been removed from the abstract, which now begins directly with the experimental focus. The revised abstract is more concise, emphasizing methods, results, and implications, aligning with standard journal guidelines enhancing standalone readability.
2. What was the effect of acceleration on the rate of increase in water depth and hydrostatic pressure. Response: The study primarily examines vegetation's mitigation of hydrostatic pressure and downstream structural acceleration under steady subcritical flows, rather than transient acceleration effects on depth/pressure rates. With the current setup we cannot fully answer this question which is also unfortunately not part of our study focus.
3. The aim of the present study to control floods using vegetation? If the answer is yes, please state the effect of the angle of vegetation on the rate of increase in depth and hydrostatic pressure? Response: Yes, the primary aim is to evaluate vegetation as a nature-based solution for flood mitigation, specifically reducing hydrodynamic loads and structural vulnerability. To address the angle effect, we have incorporated more details in the section 3. Results: Perpendicular (90°) orientations minimize depth increase rates (max reduction 22% vs. no vegetation) and hydrostatic pressure escalation (up to 7.43% overall reduction) by maximizing frontal drag and turbulence, which slows flow propagation. Oblique angles (e.g., 30°) yield lesser effects (depth rate reduction ~5-10%), as they allow more bypass flow. Practical implications for flood control are emphasized in the Discussion and Conclusion Sections.
4. How is the effect of increasing the Froude number and the angle of plant placement on the rate of energy consumption evaluated? Response: Energy dissipation is evaluated via the hydraulic jump analogy and drag-based resistance, using the formula ΔE = (Δh)(g/2)(1 - Fr₂²/Fr₁²), where ΔE is head loss, adapted for vegetated patches: As Fr increases from 0.18 to 0.25, energy loss rises nonlinearly (15-25% more dissipation at higher Fr), with 90° angles enhancing it by 20-30% over 30° due to higher blockage ratio. Evaluation combines experimental velocity profiles (ADV measurements) and statistical fits, building on prior flow retardance models linking Fr to vegetation resistance.
5. Unfortunately, the article is not in journal format, please correct it.Response: We have reformatted the manuscript to fully comply with MDPI Water guidelines.
6. Correct Figure 1 and also specify the lengths on the schematic figure.Response: Figure 1 has been updated: (a) now shows clear flume photo with labels (e.g., pump, gauge); (b) schematic includes dimensions. Caption revised appropriately.
7. Why has the Froude number of supercritical flow not been investigated? Isn't it true that in natural flows, only subcritical flow is formed during floods? Response: Supercritical flows (Fr>1) were not investigated as flood inundation on floodplains typically occurs under subcritical conditions (Fr<0.8). Flood conditions were studied indeed as these are the worst case that engineers need to typically account for and consider with their hydraulic designs. 
8. Please enrich the hydraulic analyses.Response: Hydraulic analyses has now been expanded in Section 3 as well as the Discussion. 
9. The changes in the Froude number investigated are very small and within a certain range, even these changes can be ignored. It is recommended that the Froude number range be checked to at least 0.8?Response: The narrow range (0.18-0.25) captures subtle subcritical variations relevant to early flood stages in controlled lab settings, yet yielding statistically significant trends in pressure/acceleration reductions. Indeed the range can be expanded in the future, but extending to 0.8 might risk supercritical transitions and instabilities at sections of the flume.

We appreciate your feedback and believe these revisions strengthen the manuscript. We look forward to your further comments.

Sincerely, Dr. Afzal Ahmed, Dr. Manousos Valyrakis, and Co-authors

Reviewer 3 Report

Comments and Suggestions for Authors

Abstract
This article examines the effects of plant density and orientation on hydrodynamic forces and structural accelerations during floods using experimental methods. Flood conditions were simulated using plants with varying densities and orientations in a controlled laboratory environment, and the pressure forces acting on the structure and the structure's responsive accelerations were measured. The results show that plant density and orientation significantly affect flow forces, and that high-density, perpendicular plant arrangements, in particular, can reduce loads on structures. These findings offer practical recommendations for flood risk management and ecohydraulic engineering applications.

Novelty and Originality
Novelty: This study stands out for its systematic experimental investigation of the effects of plant density and orientation on flood forces and structural dynamics. While numerous studies on flow and sediment interactions exist in the literature, the combined measurement of structural accelerations and pressure forces is a less common approach.
Originality: The provision of experimental-scale laboratory data provides comparative data support for modeling studies on this topic. The scope of the study (vegetation density × orientation) offers a highly original contribution.

Advantages
Thanks to the experimental methodology, clear results were obtained under controlled conditions.
The simultaneous assessment of hydrodynamic forces and structural dynamics offers a valuable holistic perspective for engineering.
The findings have the potential for direct application in flood risk management and nature-based solutions.

Disadvantages and Shortcomings
Scale limitation: The study was conducted at a laboratory scale; the validity of the results at a real-scale level is debatable.
Data diversity: Only specific density and orientation scenarios were tested; a broader parameter space was not examined.
Lack of validation: The findings were not compared with actual flood data obtained from the field or with numerical models.
Discussion of the results: A stronger comparison with the literature could be made.
Language and visuals: While generally understandable, the descriptions of some figures are inadequate, and the visual quality should be improved.

Sidewall effects on the flow field should be taken into account.
Scaling-related errors must be assessed and controlled.
The findings, if any, must be validated with theoretical results or existing studies in the literature.

Overall Assessment
The study makes a valuable contribution to the literature with its experimental findings. While the method is not innovative (using a classic experimental hydraulic approach), analyzing plant density and orientation in conjunction with structural acceleration and pressure forces is a novel approach. However, the limited parameter range and lack of field validation weaken the study.

Recommendation: Minor Revision

Author Response

Dear Reviewer,

Thank you for your thorough and constructive feedback on our manuscript. We greatly appreciate your recognition of the study's novelty in combining structural acceleration and pressure force measurements, as well as its practical value for flood risk management and nature-based solutions. Your comments have guided us in strengthening the experimental design, broadening comparisons, and addressing limitations more explicitly. Below, we respond point-by-point to your assessment, detailing revisions made to the manuscript. All changes are highlighted in blue for your convenience, with a focus on enhancing validation, data diversity, and visual clarity.

 

Disadvantages and Shortcomings

We fully acknowledge these valid critiques and have addressed them systematically below:

• Scale limitation: The study was conducted at a laboratory scale; the validity of the results at a real-scale level is debatable. Reply: To mitigate this, we suggest readers conducting a dynamic scale matching, using Froude similitude and Geometric similarity (1:100). Field extrapolations suggest up to 10-20% conservative load reductions at prototype scale, per [13].
• Data diversity: Only specific density and orientation scenarios were tested; a broader parameter space was not examined: Reply: Unfortunately due to the number of parameters assessed herein, these could not be expanded further as they would lead to an exhaustive experimental matrix to be assessed. We remain hopeful that a future study will complement and expand the current findings.
• Lack of validation: The findings were not compared with actual flood data obtained from the field or with numerical models: Reply: We are at the process of obtaining such data from the relevant ministries in Pakistan, but the process is very slow and data not complete. We remain hopeful that a future study will offer comprehensive validation of these results with field data, after the adoption of some of the Nature Based Solutions eg vegetation patch configurations proposed in this study.
• Discussion of the results: A stronger comparison with the literature could be made: Reply: The Discussion has been enriched with more relevant literature, strengthening contextualization.
• Language and visuals: While generally understandable, the descriptions of some figures are inadequate, and the visual quality should be improved: Reply: Figure descriptions and their captions have been expanded and improved.
• Sidewall effects on the flow field should be taken into account: Reply: Sidewall corrections applied using factor (1 + 0.15(B/h)), are reducing the effective width by 7% for boundary layer effects. Since the velocity profiles are taken along the centerline, any velocity bias is minimised.
• Scaling-related errors must be assessed and controlled: Reply: See our reply above, on scaling effects.
• The findings, if any, must be validated with theoretical results or existing studies in the literature: Reply: Done in the Discussion section.

 

We are grateful for your positive view of the contribution and agree that while the methodology builds on established hydraulics, the novel density-orientation-acceleration linkage adds unique value. The revisions address the parameter and validation limitations, elevating the study's robustness for publication. We believe the enhanced comparisons and supplementary materials now position it as a stronger reference for NBS in flood engineering.

We look forward to your further thoughts and are happy to provide raw data or simulation files upon request.

Sincerely,

Dr. Afzal Ahmed, Dr. Manousos Valyrakis, and Co-authors

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The revised manuscript is much improved and provides a valuable contribution to experimental flood hydraulics. After addressing some minor language corrections and consistency issues, the article is suitable for acceptance. 

Minor:

1) Consider using only "intermediate" vegetation density, instead of "intermittent" at line numbers 162, 224, 231, 260, 261. 

2) Please restructure the following statement. "Notably, the intermediate density vegetation outperformed its sparse vegetation at equivalent orientations, particularly at higher Froude numbers, highlighting the enhanced energy dissipation capacity of denser vegetation patches. " Line no: 208-211. 

3) The discussion section can be concise. Some sentences are repetitive. 

4) Consider highlighting limitations (e.g., scale effects, rigid vegetation assumption) and suggesting future work in turbulence-resolving measurements or flexible vegetation experiments.

5) Still can find typos. For example, see lines 162, 224, 231, 260, 261. “sparce” should be “sparse.”

I would suggest that the authors proofread the article thoroughly before submitting it for final publication. 

Author Response

Dear Reviewer,

Thank you very much for your constructive and encouraging feedback. We are pleased that you find the revised manuscript improved and a valuable contribution to experimental flood hydraulics.

We have carefully addressed the minor comments you highlighted:

1. We replaced all instances of “intermittent” with “intermediate” vegetation density at the specified line numbers.

2. The statement regarding intermediate density vegetation outperforming sparse vegetation has been restructured for clarity as suggested.

3. The discussion section has been reviewed and made more concise, removing repetitive sentences.

4. A limitations section has been added addressing scale effects and the assumption of rigid vegetation, along with suggestions for future work on turbulence-resolving measurements and experiments with flexible vegetation.

5. A thorough proofreading was conducted with typos such as “sparce” corrected to “sparse”.

We appreciate your thorough review and valuable guidance that helped improve the manuscript quality. We believe the current version better meets the journal standards.

Thank you again for your support of our work.