Effect of Land Use on Stream Water Quality and Biological Conditions in Multi-Scale Watersheds
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsDear Authors,
your manuscript deals with an interesting subject, and you analyzed extensive set of data. There is, however, the need to clarify some part, and to rewrite some paragraphs. Specific comments are below:
Lines 38-42: This sentence should be rewritten to indicate that there are more sources of pollution in urban areas, not only driven by changes in hydrology.
Lines 56-57: This part „in the Willamette Valley Ecoregion of South Brazilian grasslands, Oregon, USA“ is mixing study areas. I suggest to write „across South Brazilian grasslands and in the Willamette Valley Ecoregion in Oregon, USA“
Line 77: As you write about models, the sentence should start with „They“, instead of „It“, and change the sentence accordingly.
Lines 88-90: The sentence “Similarly,…” can be deleted, as it repeats already stated advantages of RF models.
Lines 119-121: rewrite this part, as three sentences in a row begin with “The Han River”.
Line 130: There should be”cover” instead of “use”
Lines 133-136: Why did you write that the large-scale watershed has the smallest unit. 3rd and 4th order streams are bigger compared to 1st and 2nd order streams. Please, correct this.
Line 145: Write “autumn” instead of “fall”
Figure 1. I think you should use plural i.e. “watersheds” Also, it is not clear did you show watersheds or study areas. Why are there no monitoring points on b) part of the figure?
Lines 160-169: This paragraph is redundant and can be deleted, except the last sentence, that can be added to previous paragraph. Also, write the source of data. Did you perform the measurements or did you use some official data?
Line 182: “included” instead of “include”
Lines 199-201: The sentence: “The correlation coefficient ranged from -1 to +1 and from 0 to +1, 0 indicating that there was no statistical association between the variables.” makes no sense.
Tables 2 and 3: Add “in the Han River basin” at the end of the title. TN should have two decimal places, not three. Write “N” or “n” under both tables.
Line 261: Add Table 3 at the beginning of the sentence.
Combine subchapters 3.1. and 3.2. into one subchapter, so write immediately if some parameters are ”statistically significant” lower or higher in small or large watersheds. Also, there is no need to repeat results shown in the tables. Please, explain grade system used in your country. What does ”normal” means? How many grades are there?
Lines 278-281: These sentences can be deleted, as they are unnecessary.
There are two Tables 3! Also, change the title of Table 4. What does the 3rd column stands for?
Line 288: Delete “Through Pearson correlation,”
Line 290: I don’t think all correlations were “found to be significant”. Did you check p-values? For instance, - 0.03 is probably not significant. You have to check this, and I suggest to show only statistically significant correlations (or show those in bold).
Line 296: Change “land uses” to “land uses/covers”.
Subsection 3.4. There isno need to reoeat all valuesfrom the Table 5, so rewrite this paragraph.
Lines 325-326: Does it means “change the probability of predicting water quality” or that there are different threshold ratios depending on the scale?
Line 334: it should be “Figures 7-8 visualize” not “Figure 7-8 visualizes”
Line 365: Add “for different watershed scales” at the end of the sentence.
Lines 366-369: You have to indicate which concentrations. Also, clarify this sentences, for instance it is not clear what does the “rate” means. I think you mean the share of land use, but it should be clarified. Later in the discussion, you use “ratio”, however, I think you should use “share” throughout the text.
Line 386: I think it should be “at” not “by”.
Lines 397-399: This sentence can be transferred somewhere before in the discussion”. Also, in this paragraph there should be some discussion why is this deterioration in biological status modelled on lower share of agricultural lands. Is more fertiliser used in the studied basins, can it depends on soil type etc?
Line 399: There should be reference(s) after “Previous studies”
Line- 400-402: Please be careful when writing that “intensive agriculture is better”. Rewrite this to explain more precisely what you mean.
Line 425: “reducing water quality” sound the opposite of what is aimed with increasing the share of forest.
Lines 460-462: The first line of the Conclusions should be deleted, as you did not study “actual stream restoration and watershed management”.
Be more clear in the conclusions, and clearly state the importance of forest areas.
Comments on the Quality of English Language
The English language requires only minor editing. However, please, use the same terms in the whole manuscript.
Author Response
We appreciate your thoughtful comments and valuable feedback on our manuscript. Based on your suggestions, we have made significant revisions to the manuscript. The revised manuscript communicates the key contributions and findings of our study.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsDear Authors,
I often review various articles, but never before have I had no comments on the reviewed text.
Congratulations on a well-written text on a very interesting topic.
Best regards
Your reviewer
Author Response
We sincerely appreciate your positive feedback. Your support encourages us to strive for even better work in the future. We genuinely appreciate your time in reviewing our work.
Reviewer 3 Report
Comments and Suggestions for AuthorsReview on Manuscript Number: water-2718023-peer-review-v1
Title: Effect of Land Use on Stream Water Quality and Biological Conditions in Multi-scale Watersheds
1. Summary
The manuscript provided a case study about the identification of the effects of land use on stream water quality and the health of aquatic organisms in the Han River Basin (South Korea). The study examined these effects on multiple spatial catchment scales and by comparison and examination of thresholds of land use according to watershed scales. Random forest models were developed to evaluate the relationships between major types of land use, water quality, and biological indicators.
The predicted application: “The results of this study can reduce uncertainty and provide insights for effective decision-making in developing contaminated watershed management strategies and restoration plans. Therefore, different spatial scales should be considered when developing effective watershed management strategies to sustain stream ecosystems. This is expected to help establish the criteria for estimating land-use rates to meet the health goals of stream ecosystems in watershed management.”
2. Overall opinion and comments
The subject addressed in the manuscript is interesting. Understanding and assessing the relationship between watershed land use and stream conditions is of vital importance for the planning and management of catchments. Although the study’s findings are regional, they could contribute to the international scientific literature for integrated water resources management. So, the manuscript meets the publishing objectives of the journal.
The manuscript is generally well structured and organised. But, in my opinion, the manuscript needs improvement before publication, and I have a few comments which may help to improve it.
The introduction gives an adequate background of the research. However, this study's novelty compared with previous studies needs to be highlighted, as the application of Random Forest models is not new. I recommend a revision of the last paragraph, where this aspect is mentioned but in combination with the objectives of the study, as well as the link/improvement in relation to previous studies.
Line 40 – BOD is a parameter, not a chemical or nutrient
Sentences that are not clear:
Line 47-48: “…and reduce nutrient runoff from the watershed to alleviate erosion and eutrophication [11,12].”
Line 53-55: “Riparian or local scales close to streams can better predict the impact on water quality and aquatic organisms than catchment scales [17].”
Line 93-95: “For examples, in the southeastern Queensland watershed, Australia, significant changes in fish community composition and species richness were observed at urban rates of 10.9% and 17.5%, respectively [28].”
The methodology is well described, appropriate attribution to the R Studio was provided.
Line 127-129: “Overall, the Han River basin has a lot of precipitation in the highlands (over 1,000 m above sea level)in the east and relatively little precipitation in the lowlands in the west [32], with an average annual precipitation of 1208.3 mm” – needs to be rephrased (“has a lot of precipitation”?)
Line 160 – “biological indicators such as TDI, BMI, and FAI were used”… replace “such as”
Line 185 - 2.3. Statistics Analysis – Statistical analysis?
Line199 – “Pearson correlation analysis” Are the parameters normally distributed?
Results
Line 264-267: “The average land use in urban areas was only 7.7% and 10.4% in large and small watersheds, respectively. The average land use in agricultural areas and forests was 17% and 69.3% in large watersheds and 28.5% and 54.3% in small watersheds, respectively.” - needs to be rephrased (“average land use in urban areas… in agricultural areas and forests…”)
In my opinion, it would be interesting to complement figures 5-6 and 7-8 with tables summarising the information retained from the graphs.
Discussion
Line 462 – “…and obtaining knowledge about threshold values.” The sentence needs to be revised
Conclusions could be more objective, mentioning major findings, and highlighting the potential application in practice.
Comments on the Quality of English LanguageThe manuscript needs to be revised to clarify parts of the text (mainly sentences) before publication.
Author Response
We appreciate your thoughtful comments and valuable feedback on our manuscript. Based on your suggestions, we have made significant revisions to the manuscript. The revised version now more effectively communicates the key contributions and findings of our study.
Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
Comments and Suggestions for AuthorsReview on Manuscript Number: water-2718023-peer-review-v2
Comments on the Revised manuscript
During the reviewing process, the authors made appropriate modifications, according to the reviewers' suggestions, and the quality of the manuscript was improved.
However, before publication, the text steel needs editing to correct typos, some sentences’ structure, and verbal forms. I advise professional editing help.
Minor comments:
Line 57 – what is the meaning of “local scales” in the sentence?
Line 109 – “ALE” first time mentioned in the manuscript (after the abstract) has to be written in full
Line 160 - “In this study, the biological indicators of TDI, BMI, and FAI were used."
Line 184 - 2.3. Statistics Analysis – Statistical analysis?
Line 200-201 “The parameters used in this study were normally distributed, but only the with the exception of urban proportion showed”
Comments on the Quality of English LanguageBefore publication, the text steel needs editing to correct typos, some sentences’ structure, and verbal forms. I advise professional editing help.
Author Response
Thank you for your comment.
Author Response File: Author Response.pdf
