Water Quality in a Small Lowland River in Different Land Use

Round 1

Reviewer 1 Report (Previous Reviewer 2)

The authors have significantly improved their paper compared to the previous version. They answered all my questions and in this form the paper can be accepted for publication.

Author Response

In attached file.

Author Response File: Author Response.docx

Reviewer 2 Report (New Reviewer)

„Water quality in a small low-land river in different land use”

 

The article presented for review addresses the extremely important problem of pollution of small rivers, which can be a source of significant loads of, among others, nutrients for larger watercourses.

The authors conducted a detailed study at nine sampling stations in 2017-2019 on the variability of selected physico-chemical parameters to assess the water quality of this watercourse.

 

Specific comments:

Line 17 - here it would be appropriate to state the length of the river rather than the catchment.

Lines 105-109 - here it should be clearly stated that this was the purpose of the study.

Lines 174-175 - in what specific months were the water samples taken? Were they the same months in each year of the study?

Lines 234-236 - the purpose of the study is usually stated at the end of the Introduction section.

Lines 239-243 - this section is not about statistical analysis so should not be in this subsection

Line 238 - Table 2 should not be cited here. The results presented in this table should be described in the Results chapter and interpreted in the Discussion chapter. This was lacking in this work.

Table 2 - no explanation of the abbreviations given in the table (e.g. SS, MS...).

Table 3- are these mean values for a given year? If so this should be stated in the table caption.

Results - no description of seasonal variations (within one year) of individual parameters and by year. Only changes according to catchment use are described. What is important is of course the land use, but also the data on the variability of the studied parameters in individual seasons and in successive years of the study.

Just as Table 5 shows the variability for different land uses of the catchment, it would be helpful to show the variability for individual years and seasons (seasons).

Meteorological data for individual years should also be provided - especially precipitation amounts and information on how water levels changed at individual study sites during the study.

Lines 271-275 - this section of the text should be moved to the Discussion chapter

Lines 279-283 - as above

Lines 291-294 - as above

 

Table 4 - are these mean values for the whole year?

 

Tables 3-5 - it would be useful to clarify what is meant by "homogeneous groups resulting from the statistical analysis of the results"

Lines 372-391 - this section of the text should be included in the Introduction chapter

 

Lines 414-418 - how does this section relate to the Raszynka River study?

Lines 465-470 - how does this relate to the Raszynka River study?

The Discussion chapter needs to be corrected. There is too much literature data in it, which in many cases is not relevant to the Raszynka River study. Furthermore, there is too little interpretation of the research results obtained and comparison with others. The reasons for changes in the water quality of this small watercourse should be explained here, and not just literature data that do not add anything new.

Conclusions - should also be corrected.

Lines 504-505 - not confirmed in study results

Line 507 - there is no data on dissolved oxygen content in the study results.

Conclusions are too general and do not refer to the results obtained, but rather to data well known from the literature.

Author Response

In attached file.

Author Response File: Author Response.docx

Reviewer 3 Report (New Reviewer)

With sufficient test and analysis of the water samples in the Raszynka River based on selected chemical parameters, This article describes water quality in the Raszynka River in dependence on different land use, the discussion about how land use impact the form of specific water quality is inspirational.I suggest it can be accepted after minor revision. The specific comments are as follows:

1.     the purpose of this paper should be clarified. Compared to the description in the abstract, I feel that this paper answered more than weather the small rivers can be a source of pollution for large rivers. The main content of this paper is about how land use influence the pollution in the small river, it’s more like “why small rivers can be the potential source of pollution”.

2.     The presentation of first two figures can be improved. If figure 1 can show the scale of the catchment and the land use in it, it will be more visual for the reader to understand the analysis in the discussion part. Moreover, I suggest the extent of Raszynka River should be added into figure 2 to help the reader to understand the relationship between the sampling site and the river.

3.     The documents I received were filled with corrections. I’m not sure about the reason, but I believe the authors and editors will solve this issue properly.

Comments for author File: Comments.docx

Author Response

In attached file.

Author Response File: Author Response.docx

Reviewer 4 Report (New Reviewer)

Line 96-97 – Please rephrase „Typically, the way they used catchment area has a negative impact on the water quality indicators [25-28]”. It is not understood the meaning of the content.

Line 170 -Figure 3 does not exist in the paper. Please correct this situation.

Line 271-275 – According to Figure 2 and Table 1, in the middle course of the river, there are urbanized areas. So, I don`t understand 2 things: one it is referring to the fish pond's location and the second refers to `Water from the ponds infiltrates directly to the river, evidently contributing to an increase in the concentration of NH4+`. Was it made of some analysis of some water samples from the fish ponds? Where are the results that show the fish ponds are `guilty` of the contribution of the ammonium ions concentration??

Line 281-282 – There is no specification of the location of the Commune Wastewater Treatment Plant. Is it nearing the P4, P5 or P6 location, in the middle of the river, or is it in another location?

Line 282-283 – What does it mean `NO3- concentration was at an approximate level `? Please be clearer on this.

 Line 289 – I believe the reference to Table 1 is wrong. Please correct this.

 Line 284-294 - It is not clear to me that the concentration of NO3 is higher because of the position of the Commune Wastewater Treatment Plant (near the middle of the river probably) and not because of the agricultural land use. Also, it is not clear to me if the concentration of the total phosphorus is higher because of the fact that the sample points are nearer the agricultural land or not. Please be clearer on this aspect.

 Line 302 – Please correct the word `quaity`.

 Line 301-302 – Except for the NO3 and Cl concentrations, there are no specified values regarding the acceptable values in Poland for none of the quality indicators presented in the paper. So, it is very hard for the readers to know if a value of a quality indicator is a `good` or a `bad` value.

 Line 335-337 – What does it means `at an approximate level`? What is the CMA for Poland legislation point of view?

 

Line 343-350 – The are no correlation between the values presented in the Table 4. Something is wrong. Why at the highest value of EC are small value of chloride and small alkalinity? For example, look at the P1 vs P4 in 2017.

 Line 425-427 – It is not clear to me where in the paper where demonstrated the `Just like in our research studies have shown that in the small rivers contains high concentrations of nitrates and phosphates which led to the quick growth as well as death of plants and algae `

 Line 462-463 –Reference 71 is not for sustaining the affirmation made on these lines. Please put the correct reference instead.

 Line 506-508 – Please indicate where are the result that was obtained for dissolved oxygen for the Raszynka River in order to sustain the affirmation that was made in the paper.

Comments for author File: Comments.pdf

Author Response

In attached file.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report (New Reviewer)

Accept in present form

Reviewer 4 Report (New Reviewer)

All the suggested correction was made.
Good luck.

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

Commentary on the manuscript

1.     Brief summary of the manuscript

The article under review analyzes the water quality in the small river Rashinka on the basis of physical and chemical parameters depending on different land uses.

The introduction highlights the problem of water quality in small lowland rivers, their impact on the state of the entire river system of Poland, as well as all lakes and reservoirs through which these rivers flow. The main sources of pollution of small rivers are given. The purpose of the study is formulated.

In the Material and Methods section, the authors present the hydrological characteristics of the river under study, the climatic features of the region, and the characteristics of the catchment area. A sampling map is provided showing sampling points. The periodicity of sampling, methods for determining the main parameters, methods of mathematical data processing are given.

The authors used Ammonium (NH4+), Nitrates (NO3-), Total Phosphorus (RP), Chlorides (Cl-), Chemical oxygen demand (COD), pH, total alkalinity, electrical conductivity (EC) as the main parameters.

In the Results section, changes in the determined physicochemical parameters of the river by years and by sampling points are given, compared with the standards in force in Poland, the water quality is assessed for each parameter, an explanation is given for the excess of certain parameter values, the relationship between river water quality and land use on adjacent territory.

The Discussion section discusses the problem of pollution of small rivers associated with natural and anthropogenic factors, the reasons for the high content of certain physico-chemical parameters in rivers.

The main conclusion of the article: The structure of land use affects the quality of water in the Rashinka River. The agricultural use of the watershed and the presence of urbanized areas contribute to an increase in the pollution of the Rashinka River with biogenic substances (total phosphorus, NO3- and NH4+), deteriorating its quality and contributing to eutrophication.

2.     Strengths of the manuscript

The authors analyzed 4 versions of the indices, taking into account a different set of indicators, and proposed the most rigorous, from their point of view, option for calculating the water pollution index.

The results and discussion presented in the article fully reflect the goals and objectives.

The article is written in good scientific language, clearly structured, readable and understandable to a wide scientific audience.

The graphs and figures presented in the article are made visually, the designations in them correspond to the presented legend.

All these aspects are the strength of the manuscript.

3.     Request for authors.

In the "Introduction" after the formulated goal, it is not necessary to give the timing of the work and the analyzed parameters. All this is given in the "Materials and Methods" section.

In the «Results» section, the authors compare the results obtained with the “norms in force in Poland”, it is necessary to indicate the link where these norms are indicated. This information should be given in the «Material and Methods» section.

Comments for author File: Comments.pdf

Reviewer 2 Report

Title: Water Quality Parameters in a small low-land river in different land use

 

Authors: Beata Rutkowska, Wieslaw Szulc, Wiktor Wyżyński, Katarzyna Gościnna, Stanislav Torma, Jozef Vilček

 

The aim of the paper is to assess the water quality of the Raszynka River based on several chemical parameters and physicochemical indicators. In their work, the authors used simple statistical analyses and comparisons of measured data with surface water quality standards in Poland. The purpose of the work was to prove the hypothesis that, in case of pollution from different sources of pollution, small rivers, tributaries of large rivers, can significantly pollute large rivers.

The subject of research is interesting, but the paper has major flaws that need to be fixed before possible publication in the journal Hydrology. The paper is not ready for publication.

First, the work does not represent a significant and original scientific contribution, and the goal of the work is too ambitious in relation to the data used in the work. The authors focused on only a few chemical parameters and pollution indicators and did not consider other pollutants that can potentially occur because of registered activities in the Raszynka river basin. Here, above all, I am referring to the influence of agriculture and urbanization, which the authors emphasize have the greatest influence on water quality. In addition, the authors did not address the possible influence of groundwater on the river's water quality, nor did they show that groundwater does not have a significant influence on the formation of the chemical composition of water in the river. In the paper, the authors list various pollutants, but do not describe their characteristics in detail, as well as possible cause-and-effect relationships between the place of origin of the pollution and its appearance in the river. Although in the discussion chapter the authors refer to various literature, based on which they theoretically consider the possible impacts of various sources of pollution, they focused too little on their own data and what they show.

The methodology applied in the work is very simplified and insufficient for distinguishing individual impacts of pollution on river water quality. The statistical analysis, analysis of variance, which is applied in the text, is very poorly explained, the results of the analysis are not interpreted at all, and it is not clear how the results of this analysis contribute to the interpretation of the results presented in the paper.

Below are the specific comments:

1. I suggest removing the word "Parameters" from the title of the article.

2. Line 18: add chemical parameters in the first sentence

3. Line 26: I suggest changing the word elements with substances

4. Line 31-32: an incomprehensible sentence that should be written better.

5. First sentence in introduction: the authors claim that the water quality in small rivers should have a significant impact on the entire river system in Poland, but they do not provide any evidence for this, nor do they refer to previous, published results.

6. Line 38: which research? please explain

7. Line 47, line 94: missing literature references that should be referred to.

8. Lines 98-101: in relation to the previous sentence from the text, these sentences are completely unclear. It is not clear to which agricultural catchment the remark in the text refers.

9. Figure 1: the north mark on the maps and the graphic scale are missing, the location of the river on the map of Poland is barely noticeable, and the more detailed picture with the position of the river on a larger scale is of very poor quality and resolution.

10. Lines 110-113: the description of locations and sampling sites is not satisfactory and should be better described. It is necessary to provide a detailed description of each of the 9 sampling locations: where the sampling takes place, at what depth, a brief description of the location itself and what it represents, that is, based on which criteria it was chosen as a sampling location.

11. Table 2: the meanings of the names of the columns in the table are unclear. The meaning of individual statistical parameters was not explained. Neither the method of variance analysis nor why it was applied in the text is explained. Finally, table 2 should not be in the chapter methods, but in the chapter results. In the chapter methods, the description of statistical indicators and what they represent in the context of specific research should be written.

12. Why are the norms or quality standards against which the results of chemical indicators are compared not described in the chapter on methods?

13. Table 3: the meaning of homogeneous groups, which are listed in the table, is unclear. They should be better described in the methodological part.

14. Line 169: please explain a cause-and-effect relationship between the nitrate values ​​in the river and the local WWTP. It's just a guess, with no evidence presented.

15. Line 188: I ask that the authors better explain the possible influence of vegetation at a specific location on COD.

16. Line 200: I ask the authors to better explain the pollution with corridas: what are the pollutions, why does the accumulation of chloride occur in certain sections of the river?

17.Line 207: the authors did not provide sufficient evidence for this claim. It is possible that underground water has some influence on the water quality of the river, in certain river sections.

18. The entire discussion chapter is too general. The authors do not connect the results of their research with the published results of similar locations in the world. They did not refer to the results of the statistical analyses from Table 2 at all.

19. The conclusion is too short. It should be written in a better and more specific way.