Influence of Natural Barriers on Small Rivers for Changes in Water Quality Parameters

Round 1

Reviewer 1 Report

General comments

 

In general, the article fits the theme of the special issue "Monitoring of Freshwater Biodiversity and Water Quality". However, in its current form, the work does not answer any questions in a significant way, even though the authors have collected quite extensive and undoubtedly interesting research material.

 

With the method of data analysis used by the authors, it is impossible to determine what factors actually affected the quality of water, i.e. how individual factors: the catchment basin and the beaver barriers on the river influenced it. This, in my opinion, does not allow us to draw appropriate conclusions.

 

The data were used from different rivers in different locations, but the research material is too small to be treated as a meta-analysis, rather there was a blurring of dependencies occurring in the individual studied systems, and this is one of the reasons that prevented obtaining clearer results of the analysis. The studied rivers and research points were poorly described, but they probably constituted such a heterogeneous group that generalization based on them was simply not very successful. Therefore, it would be advisable for the authors to rethink the concept of their research and perhaps apply a more individual approach to the study objects.

 

The paper lacks reference to the basic data on the values of the tested indicators (concentrations and values of additional indicators), without which the presented analyzes remain unclear. The authors present the relationship between the indicators and test sites, while we do not know what the actual quality of the tested waters was (especially since water quality is the topic of this paper). A different interpretation situation occurs when the waters are of good quality and when we are dealing with heavily polluted waters. In this paper we know nothing about it.

 

In my opinion, the paper requires a thorough remodeling of the way the results are presented and interpreted.

 

Comments to chapters

 

Introduction

The first 2 paragraphs are far too general. Discussing the world's water resources and the natural and economic role of water itself, is not the best start to paper on the functioning of small rivers in local conditions. It would be better to focus on the factors determining the water quality of small rivers in the context of the use of catchments and the impact of barriers (natural and artificial) on their functioning.

Page 2, line 4: “1980s” instead of “80s of, the twentieth century”

 

2.1. Study area

It would be advisable to place a map with the location of the research points and their catchment areas, as well as a more accurate description of the studied rivers (the size of the catchment areas, the percentage share of various agricultural lands, average flows, etc.).

Figure 1.

Such arrangement of research points (AB and BB) allows only the assessment of the change that occurs during the flow of water through the beaver dam. However, this is not a complete impact of such structures, because it does not take into account the changes that occur as a result of water retention in the pond above thge dam. For a full assessment, an additional point at each location would be needed, located on the river above the extent of damming (upstream of the reservoir).

If the authors have not conducted such research, it will be impossible to complete it in this paper, however, if the authors plan further research, they should consider extending the research to this element (the river above the reservoir).

 

2.2. Sample collection

t is not known whether 20 research points are for 20 pairs of points (AB+BB) or 10 AB points + 10 BB points. It must be clearly stated how many samples there were in total. This is important for interpreting the results of statistical analyses.

 

3.1. Spatial analysis

Text should be first, then figure and table

Figure 1: The correlation says little about the change in water quality before and after the beaver dam. The high correlation coefficient between sites AB and BB means here that the barrier did not significantly affect the water quality.

 

3.2. Changes in water quality parameters

Table 2: The huge differences in the results between the minimum and maximum results of the IA analysis, while invisible in the average seasonal variation, require a more detailed explanation - what are the reasons for such differences?

The low mean results are probably the result of the overlapping and blurring of the variability of individual research objects (extreme values suggest that these variability were significant), which is averaged in such a presentation of the results. I'm afraid that here is a situation similar to that of the jocular sentence that "Man and his dog have statistically three legs. After all, it is statistically the truth”. It seems that this is a consequence of combining all (different in many respects) objects into one group.

Page 7 (text, 2nd and 3rd paragraph)

The discussion of the results is largely based on speculations regarding relationships (catchment, river, sediments, retention in ponds), which in fact were not presented by the authors for the studied sites. The presented results also do not allow to assess whether the changes occurred along the river route (the impact of the catchment area or within the beaver ponds).

Table 3.

Table 3 shows, that land use had strong statistical dependence on water quality parameters, but

it has not been explained how this influence was shaped and what it consisted of. This requires more accurate analysis.

Author Response

In annex

Author Response File: Author Response.docx

Reviewer 2 Report

Comments to the authors:

The authors studied the impacts of the changes in water quality parameters on the natural barrier (Castor fiber L). Overall, the study is methodological sound, with promising results and discussion. However, prior to further consideration, some comments need to be addressed.

(i) Title is slightly confusing and lengthy. Please rewrite. 

(ii)  Huge modifications are necessary for the introduction section. The research gaps and significance of the study are not shown. Moreover, the authors should provide more precise research objectives in this study. Also, please highlight some incidents of heavy metal pollution that occurred in the region which drove you to perform the study.

(iii) Abstract: Provide a sentence or two to highlight the novelty of the research.

(iv) Discussion is lacking in this study. What is the spatial difference? What about drivers for the seasonal changes? What are the proposed mitigations? What should the government do for proper water quality management? Effects from changing land use or anthropogenic activities? The difference between upstream or downstream is not provided.

(v) Table 1: Why do you consider only r>0.5 and 0.7?

(vi) Convert Table 2 to a box plot will be much clearer for readers.

(vii) How did you consider the land use effects? What are the types of land use considered? Not clear.

(viii).  Some relevant literature is missing in this study.

a.      doi:10.1007/s10661-020-08543-4.

b.      doi: 10.1007/s10661-021-09202-y

(ix).  Conclusion section seems to be a repetition of the results section. Huge modifications are required. Please provide insights into this study and what can be further done in the future.

(x).  Implications for future research may also be included in the conclusion at the end.

Overall, no significant English grammar was detected. 

Author Response

In annex

Author Response File: Author Response.docx

Reviewer 3 Report

1. Abstract is not more informative, Add more findings here

2. Add more recent papers in introduction section, Main objective of the present study is not wider and add more objective to monitor the impact of changes in natural ecosystem 

3.  Add surface water quality index to evaluate the quality of water in the study region 

4. Add more classification methods to assess the quality of water 

5. Use GIS techniques to represent the contaminated zone in the river 

6. Add spatial distribution of each parameter in the study region 

7. Add PCA statistical techniques to understand the relationship among them 

8. Revise conclusion based on the correction carried out in the main text 

 

Check spell and typo error in the text, 

Author Response

in annex

Author Response File: Author Response.docx

Reviewer 4 Report

The manuscript changes in water quality parameters of small rivers in eastern Poland that were assessed for ten barriers. The average annual changes in water quality parameters are characterized by slight changes in concentration from a decrease of 4.6% to an increase of 7.5%. The manuscript is written well and organized. However, the authors needed to improve their manuscript in order to be processed further. Below are some of my comments:

 Title:

·        The authors need to double-check the language of the title.

 Abstract:

·        The authors should define the abbreviations in this section.

·        Also, the authors should provide the reason for performing their study or/and the importance of their study.

·        More numerical results should be presented.

·       Introduction:

·        More literature of reviews should be presented.

·        The authors should discuss clearly the purpose of this study.

·       Materials and methods:

·        The authors should provide a map of the study area showing the studies river and the location of collected data

·        The authors should provide more details on the “Sample collected”

·        The authors should provide more details on “Data analysis”

·        Make a flowchart of how to do your work.

·       Results and Discussions:

The authors should discuss their results. I did not observe any discussion in the previous study.  

 

·       Conclusions: The limitations of the study should be presented in this part. Also, future work should be presented in this part. 

The authors should send their manuscript to a Professional English Editor 

Author Response

In annex

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

General comments

The authors have significantly improved and modified the paper. Changing the assumptions of the work (focusing on two objects) was a good decision in my opinion. In its current form, it is definitely more coherent and clear. A positive change is also more discussion of the results and the addition of additional papers to the References.

However, I still think that the first two paragraphs of the introduction might be appropriate for an introduction to a master's thesis, but for a scientific publication - they are simply too general (especially the first paragraph).

 

Additional remarks:

Page 3, Figure 1:

The numbers visible on the map of Poland are not described: either they should be removed and only green fields should be left (in the legend or title it should be written that these are national parks), otherwise all numbers should be described in the legend or title!

Page 5.

Table 1 and Table 2: The formatting of the tables is severely flawed in the delivered version of the paper.

Page 6.

The title of table 3 is in Polish.

Page 11.

Table 6 is cited earlier than Table 5, so the order should be reversed. In this section on water quality in relation to catchment use and seasons, it is not clear whether this still applies to the same rivers and research points as presented in Materials and methods. This should be explained in the titles of tables 5 and 6, or clearly stated in the text.

Author Response

In annex

Author Response File: Author Response.docx

Reviewer 2 Report

Comments to the authors:

The authors have substantially addressed comments that I raised during the first review. However still there are some more issues to be addressed.

(i) The introduction section has been improved, however still there the research gaps were not identified in this study. Please highlight it in the study.

(ii) Combine Photo 1 and Photo 2 into one photo and rename it as Figure xxx.

(iii) Rename Section 3.2: The naming Impact Factor, is not scientifically sound. Impact Analysis might be better

(iv) For BACI analysis, some relevant references can be included.
a.      doi:10.1007/s10661-020-08543-4.

b.      doi: 10.1007/s10661-021-09202-y

(v) Again, the conclusion section seems to be a repetition of the results section. Huge modifications are required. Please provide insights into this study and what can be further done in the future. Highlight the limitation too.

Moderate English revision is necessary.

 

Author Response

In annex

Author Response File: Author Response.docx

Reviewer 3 Report

Accept

Minor english typo error 

Author Response

The paper was checked by a native speaker.

Reviewer 4 Report

It is good to go

No issue about English language 

Author Response

Praca została sprawdzona przez native speakera.