Increased Riparian Vegetation Density and Its Effect on Flow Conditions
Round 1
Reviewer 1 Report
The problem of water resources is extremely relevant in the modern world. In many regions, it is water resources that limit economic development. In addition, the favorability of the human habitat is also directly dependent on water resources. The physical and biological structure of riparian vegetation fundamentally influences the floodplain roughness, thus the flood velocity and flood levels of a river. From this point of view, this paper is relevant because it draws attention to an important issue. The theme of the paper corresponds to the theme of Sustainability.
Scientific novelty
The scientific novelty lies in provide detailed spatial data on vegetation density of a floodplain, and to model the effect of the actual vegetation and various scenarios on flow conditions.
Scientific and practical significance.
The results obtained are of great importance. Applying the LiDAR based 2D flow modelling makes it possible to plan sustainable riparian vegetation maintenance (e.g. forestry, invasive species clearance) from both the ecology and flood control perspective.
Title
The title corresponds to the content. However, it is desirable to use a shorter and more capacious title.
Abstract
The abstract is acceptable.
Introduction
In the introduction, the relevance of the study is well substantiated and the state of the problem is described. The aim is formulated clearly.
Methodology approaches
The methodology approaches are described in detail. The authors used methods adequate to the tasks set. Adequately selected methods allow us to consider the conclusions justified. LiDAR data were applied to evaluate the density and roughness of the submerged understory vegetation over the densely vegetated floodplain of Lower Tisza, Hungary. Then HEC-RAS 2D modelling was applied to analyse the effect of the actual vegetation on flow conditions.
Research results
The research results are illustrated with figures and tables that are informative and do not duplicate each other. The paper contains 3 informative tables and 7 visual figures. I have no comments on the quality and informative value of the figures. The results are presented clearly.
Conclusion
The conclusions drawn from the results are reasonable. The paper will be of interest to a wide range of readers whose scientific interests are related to water resources. Although English is not my first language, I read the paper with interest and had no difficulty understanding it. The paper is fully appropriate to the topic and level of Sustainability. It is also possible to discuss limitations in the areas of application of the conclusions and priority areas for further research. This improves the understanding of the research results. It would be interesting to assess the impact of different riparian vegetation options on biodiversity. I can assume that the more variants of riparian vegetation, the greater the biodiversity. Therefore, it is important to find the optimal balance in terms of reducing the risk of floods, favorable human habitat and biodiversity conservation.
Author Response
Dear Reviewer,
Thank you for reviewing our manuscript, and for the very good opinion on our work!
We have considered your suggestions and corrected the text accordingly. We hope these changes meet with your approval.
In the enclosed file you can find our responses.
Thank you very much!
Tímea Kiss
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The authors evaluate the impacts of floodplain vegetation density on flow scenarios. The paper is well written and conceived and is meaningful application of the technology. Overall, I congratulate the authors on effectively communicating this work.
The studied river has very low gradient, how applicable are these results to other rivers with steeper gradients?
The introduction or study area section would benefit from a description of the economic impacts of these flood events.
Comments:
Line 48: True, but the riparian vegetation can also increase bank stability. This entire section seems to imply that excessive riparian vegetation is a bad thing, which isn’t necessarily true.
Line 100: I think the authors mean “dynamics” not “dynamism”
Line 110: “were skipped” is a bit odd. Suggest replacing with were “abandoned” or “replaced”.
Line 111: “Gave up their lands”, suggest “ended cultivation”
Line 133: This flood in 2006 is brought up as if it has already been discussed at this point, when it has not. I assume this is referring to the early 21st century flood mentioned in line 113. If so, replace “early 21st century” with “2006” to make this linkage clear.
Line 136: I assume this Szeged station is downstream of the study area? Please make this clear.
Line 152: Do you have a citation for HEC-RAS 2D?
Line 197: Please provide a bit of background information for this model.
Line 275: What is KÖTIVIZIG? This needs to be described, it is never mentioned again.
Line 318: “poplar plantations are, but” suggest replacing with “poplar plantations occur, and….”
Line 327 (Figure 4): What are the narrow strips of black on the west bank of the channel? Are these unclassified areas? If so, this needs to be described in the figure caption.
Line 371 (Figure 5): Would be helpful to briefly describe each scenario in the caption.
Lines 503-504: “The primary function of the low-gradient, lowland rivers is to support the propaga-503 tion of flood waves”. Really? What about the ecological value of the river? I think this statement needs qualification, the primary “hydrological function”…
Line 505: As far as a can see, no hypothesis statement has been made. There is none in the objectives section. Please add this hypothesis statement at the end of the introduction.
Line 535: replace “are” with “occur”
Line 540: What do you mean by “which were localised by our study”? That they occurred only in localized areas?
Line 552: Why is “historical changes…” bolded?
Line 559: Relace “In the 19th century…” with “In the scenario reflecting 19th century conditions (S_meadow….” This avoids confusion.
Line 567: “will invade”, are we positive this will occur? I’d suggest taming that down to “are likely to invade”
Line 572: Be clear and replace “these” with specifics. Increased vegetation density and spread of invasives...
Line 585: Not sure what is meant by “cleared” vegetation? Has there been some removal of vegetation prior to the 2006 model run?
Line 597: As in line 567, the authors speak (and in the future, it will further increase to) as if increases in invasives are inevitable. As we don’t know the future for a fact, these statements need to be qualified, with possible increases, or similar language.
Line 605: Could the possible channel incision not reduce the overbank flow?
Line 611: “All”? what about the possible increase in channel incision?
Line 637: “and it causes serious allergy” feels unnecessary.
Line 641: By “create low-density plots” you mean “reduce vegetation density”?
Line 650: Has the vegetation situation changed since 2006, the time of the model runs? If so, how? This would be relevant information to add to this section.
English is excellent overall, a few cases of odd phrasings used which I have highlighted in my comments.
Author Response
Dear Reviewer,
Thank you for reviewing our manuscript, and for the very good opinion on our work! You helped a lot to improve the quality of the paper, and we appreciate that!
We have considered all your suggestions and corrected the text accordingly. We hope these changes meet with your approval.
In the enclosed file you can find our responses.
Thank you very much!
Tímea Kiss
Author Response File: Author Response.pdf
Reviewer 3 Report
In this manuscript (sustainability-2549706) entitled Increased riparian vegetation density and its effect on flow conditions: a case study on a floodplain highly invaded by invasive plants’ submitted to Sustainability, Tímea Kiss and colleagues have employed LiDAR data to evaluate the density and roughness of the submerged understory vegetation over the densely vegetated floodplain of Lower Tisza, Hungary, and provided detailed spatial data on vegetation density of a floodplain, and modeled the effect of the actual vegetation and various scenarios on flow conditions. According to the results, since the 19th century, the increased vegetation density is responsible for a 17 cm flood level increase, and if the vegetation grows even denser, a further 7 cm could be expected. As the vegetation density increases, the overbank flow velocity decreases, and the crevasses and flood conveyance zones gradually lose their function. Authors concluded that applying the LiDAR based 2D flow modelling makes it possible to plan sustainable riparian vegetation maintenance (e.g. forestry, invasive species clearance) from both the ecology and flood control perspective. This research is interesting and complete, and suitable for publication on sustainability. Here, I listed some minor concerned to be addressed to improve the quality of this manuscript.
1. In the revision, the invasive plants species analyzed in this study should be described.
2. In this manuscript, authors analyzed the data collected in 2006, what is the situation for recent years?
3. For the Figure2, 3 and 7, significance in difference should be analyzed and labeled.
4. Full names for abbreviations LiDAR and HEC-RAS 2D should be spelt out at first place for appearance in the revised manuscript.
Author Response
Dear Reviewer,
Thank you for reviewing our manuscript, and for the very good opinion on our work!
We have considered your suggestions and corrected the text accordingly. We hope these changes meet with your approval.
In the enclosed file you can find our responses.
Thank you very much!
Tímea Kiss
Author Response File: Author Response.pdf
