Influence of Anthropogenic Load in River Basins on River Water Status: A Case Study in Lithuania

Reviewer’s comment

Our response

Reviewer #1:

1.       

Abstract

 The abstract must be rewritten, and should give a pertinent overview of the work (background and the purpose of the study, briefly description of methods, main findings and conclusions or interpretations).

Corrected in the manuscript.

2.       

Introduction

The background of the Lithuanian river water quality research and the identification of potential water quality threats have been adequately described, but the purpose of the article is not clearly defined.

The aim of the research was written in the manuscript.

3.       

Materials and Methods:

4.       

Water sampling periods are not a part of the description of the study area (lines 115-116). Instead of this, it's better to present a brief description of the studied surface bodies of water (size, geology, etc.), for example in a table.

Corrected in the manuscript.

5.       

Figure 1 is of substandard quality. Everything the reader can see is the road network. The objects of the study are rivers, not roads. Prepare a map of the Lithuanian river network and place your water sampling stations on it.

Corrected in the manuscript.

6.       

The standard LST EN 13342–2002 (line 125) describes method of Kjeldahl nitrogen (TKN) determination, not total nitrogen (TN). TN = Kjeldahl nitrogen + nitrate nitrogen + nitrite nitrogen. TKN measurement results are not discussed in the manuscript. So, why was TKN determinated?

Thank you very much for noticing the inaccuracy. Method changed.

7.       

The standard for the determination of ammonium nitrogen was not given (lines 128-129). The method of citing of the applied standards should be unified.

The standard for the determination of ammonium nitrogen is given in the manuscript. The method of citing the applicable standards has been unified.

8.       

What does the acronym SWF means? (line 190).

SWFs (Dispersion reduction factor) To evaluate the problem of multicollinearity

9.       

Results

This part of the manuscript needs some improvements in the text.  Repetition of the same phrase from page 3 (see lines 115-116 and 195-196).

The duplicate sentence was removed from the lines 195-196 of the text.

10.     

Do not include the graph name in the graph itself (Fig. 2).

Corrected in the manuscript.

11.     

Please, use acronyms TN and TP, not N total or P total in Figs 3-4. Also in the text, for example line 242.

Corrected in the manuscript.

12.     

In Figure 4 loads are given as a percentage, so why is the caption stated that the loads are in metric units (t/year), delete “(t/year)”. What do the numbers next to the names of river basins mean? Whether they are ID numbers of bodies of surface water? This should be explained.

Units were deleted in the manuscript.

Names of rivers and Water body code

13.     

Unclear phrase (line 242). Change "total N (Y)" to "(TN is dependent variable Y)". Check it out also lines 250, 263, 270, 281.

Changes made according to your suggestion.

14.     

Discussion

Baltic See basin, not catchment (line 299).

Changed in the manuscript.

15.     

What does "and more" (line 305) mean?

Explained by expanding the sentence: “…climatic conditions, types of soil and land-use, and human activities.”

16.     

BOD (Biochemical Oxygen Demand) is the amount of oxygen consumed by bacteria (and other microorganisms) needed for decomposition of organic matter in the water under aerobic condition. So, it cannot be leached from the catchment area, as is the case with phosphorus (line 329). BOD loads cannot be carried by water from diffused and point pollution sources (lines 333-335), only waters from this sources have appropriate values of BOD.

Corrected in the manuscript. ‘’BOD load’’ changed to ‘’organic loads’’.

17.     

Conclusions should contain more general observations, patterns, or trends resulting from the work, and not only literal replications of the results.

Corrected in the manuscript.

18.     

Conclusions

Names of the ecological status classes “very good”, “good”, “moderate” and “bad” should be given in quotation marks,  consistently throughout the whole text. There is no “average” ecological status class, but “moderate”.

Corrected in the manuscript.

19.     

In chemical formulas proportionate numbers of the elements included in a compound should be given as subscripts. For instance: NO3-N, not NO3-N (line 53); BOD7, NH4-N, NO3-N, etc., not BOD7, NH4-N, NO3-N (Fig. 2). Please, check the entire manuscript.

Corrected in the manuscript.

20.     

Acronym for Total Nitrogen is TN (not NT, as in lines 248-249, 255, 331), for Total Phosphorus is TP (not PT, as in lines 270, 277, 278, 329).

Corrected in the manus.cript.

21.     

Some of the punctuation errors founded in the text (check entire body text necessarily):

Delete a comma after the full stop mark (line 58).

Put a full stop mark after the word “areas” (line 76).

Reference is a part of the sentence, so delete full stop mark before [51] (line 87). The same remark applies to line 302.

Delete one full stop in the line 322.

Corrected in the manuscript.

Reviewer’s comment

Our response

Reviewer #2:

1.       

In the section Abstract please clarify or rephrase the sentences in the lines 27 to 37 as it is hard

to follow the idea behind these sentences.

Corrected in the manuscript.

2.       

Please rephrase the beginning part of the following sentence The authors of [41] pointed out the

substandard practices of wastewater treatment in developing countries by using Joshua et al. (2017) have pointed out that substandard practices of wastewater treatment are utilized in developing countries.

Corrected in the manuscript.

3.       

Please separate two sentences by using a dot in the lines 76 and 77

Corrected in the manuscript.

4.       

Please provide an explanatory text for BOD7 when this abbreviation is used for the first time in

the manuscript, indicatively in is in the sentence in the line 93

Corrected in the manuscript.

5.       

Please replace the term of biogenic substances with nutrients in the line 97 and elsewhere in the

manuscript as nutrients is more commonly used term in the international audience.

Corrected in the manuscript.

6.       

It is unclear what is meant by the part of sentence in the brackets in the line 102 as the text

presented in the brackets conflicts with the part of sentence in the line 101. Please clarify what is

retained where.

It was misspelled, the text in the brackets was removed.

7.       

Please use the terms diffuse pollution and non-point source pollution consequently throughout the

manuscript. As the meaning for both terms is the same it is suggested to select one term and use it

throughout the manuscript. It is not clear why is some sentences the term of diffuse pollution is used,

while in other sentences non-point source pollution

Corrected in the manuscript.

8.       

Please clary or rephrase the sentence in the lines 113 to 114 as it is unclear how water bodies in

good condition do not comply with the water quality standards. If water bodies comply with the water

quality standards then those water bodies can be described as being in a good condition, if water

bodies does not comply with the water quality standards then those water bodies can be described

as being in moderate, bad or very bad condition.

Corrected in the manuscript.

9.       

Please clarify the sentence in the lines 127 to 130 as it remains unclear which water quality

parameter was analyzed using which method, especially as it concerns ammonium-nitrogen. Also

please check the necessity of all brackets used in this sentence as it some places it seems to be too

many brackets, which makes it confusing to read.

Corrected in th each subsequent indicator is markede manuscript.

10.     

The coefficient bj is not presented in the formula (1) in the line 177, but is mentioned in the

paragraph below the formula. Also the coefficient of xj is not present in the formula (1). Please

clarify what is the meaning of bj and xj.

xj  each subsequent environmental indicator is marked

11.     

It remains unclear why in Figure 2 only 4 water quality classes are mentioned by taking into

consideration that according to the EU Water Framework Directive water quality should be

evaluated and presented in 5 quality classes.

Fo the fifth ecological status class corresponds to 0 rivers studied. There are no fifth-class rivers in this study.

12.     

The Figure 2 is not centered and goes out of the page borders.

Corrected in the manuscript.

13.     

If the results of SWAT model are used in this study please indicate in the manuscript what is

the performance of the model by presenting calibration statistics such as coefficient of determination (R2

) and Nasch–Sutcliff coefficient (N-S) for simulated and measured values in case of discharge and concentrations of substances of interest

Predicted values generally matched well with the observed values during calibration and validation - R²≥ 0.6 and Nash-Suttcliffe Efficiency ≥ 0.5, in most instances.

14.     

Figure 3 and 4 are out of the page borders.

Corrected in the manuscript.

15.     

All tables included in the manuscript are out of the page borders.

…

Reviewer’s comment

Our response

Reviewer #3:

1

Page 4, lines 156-157: "…that one resident generates 25,6 kg of waste according to the BOD7, 4,4 kg of total NT, 156 and 0,9 kg of PT." decimal numbers must be separated by a full stop, not a comma. Please correct.

Corrected in the manuscript.

2

Page 9, line 265: "Table 2. The influence of anthropogenic loads in basins on the total nitrogen concentration in the water." should be Table 3. Please correct.

Corrected in the manuscript.