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Peer-Review Record

Impact of EU Environmental Policy Implementation on the Quality and Status of Greek Rivers

Water 2021, 13(13), 1858;
Reviewer 1: Anonymous
Reviewer 2: Anonymous
Water 2021, 13(13), 1858;
Received: 27 May 2021 / Revised: 24 June 2021 / Accepted: 30 June 2021 / Published: 3 July 2021

Round 1

Reviewer 1 Report

The authors


Important points:

  • The Methods need a major overhaul. Many aspects are not sufficiently explained or mentioned at all. In some cases, it is really unclear what the authors conducted. From the methods section, it is also unclear to me which statistical tests and programs were used for this work. Also, how many measurements were analyzed per year and locale? How are multiple measurements treated? Were they averaged, etc?
  • The Discussion is interesting and provides good background about the factors that may have affected primarily the ecological status estimates. However, while these paragraphs are informative, in many cases there is no direct relation to the results at all. There are numerous paragraphs where not a single result is referenced to which the discussion applies. The author must further link their results to the provided discussion, at least giving a few examples to which the current discussion applies.
  • Technicalities: There are many instances where the common formalities of scientific writing aren’t followed, such as the proper introduction of abbreviations, proper cross-referencing in tables, etc. Many I have pointed out in the comments below and I strongly encourage the authors to critically check their manuscript regarding such issues.



L11:  “chemical-physicochemical”  is it intended not to call it phyisco-chemical parameters?

L20: I think it should read mechanistically, also it is unclear to me what mechnaistc means in that context. Please clarify the sentence



L78: I don’t think a Wikipedia reference to the meaning of “bureaucracy” is required.

L77 – 81: These are rather drastic assessments that require a reference.

L90: … were considered

L:96 “chemical-physicochemical” is mentioned again, which I think is  uncommon choice of words. Physicochemical is common lingus in my opinion.

L97: Provide some examples of “biological quality elements” for reader.

L100: It is totally unclear what metric or analyses have been conducted with the macroinvertebrate data. Diversity, abundances indexes, species richness?

L100: database (please correct in the whole MS, e.g. see L 103 again)

L108f: In those cases where additional data from third party providers was used, it would be important to note, if they originate form the same 18 smapling locations or are at least close to them.

L114: Please provide a reference to that method.

L116: I was unable to find the abbreviation “TP” explained prior to this line. If you

are referring to total phosphorous, please introduce this abbreviation. The same applies to all other abbreviations, even if they may be considered common.



L121-144: This is not a presentation of results but rather introductory descriptions or in some cases discussions. This section should be included in the introduction or be removed from the results section.

L150: Figure Provides a very good overview of the study area, something that was missing from the Methods section. Consider moving it there.

L153: Table 1 is unfortunately merely discussed at that point. In case that Figure 1 is moved to the methods section, then Table 1, giving a methodological overview of the waterbody characteristics, should be moved there as well.

L162: There is no explanation given wat H, G, M , P, B means. Please provide the full name. Also, I would encourage to never use any 3D display of data that can be displayed 2D. It is neither area-true nor degree-true.

L169: It is still unclear at that point of the manuscript how the ecological quality is categorized. At minimum, provide a reference that details the process. I would however recommend to describe it briefly in the methods as this is the most integral analytical part of the whole paper.

L 174: The abbreviation of “ecological status” is not introduced in the table heading. Please revisit all abbreviations in the manuscript and check if they have been properly introduced.

L 180f: The table header is very confusing: First there is a line break between B and Q for instance, which makes it seem as if they are different entities. Also, abbreviations such as BQ should not contain a space. The same applies to ES, which throughout the MS is used without a space. Also, please add references to the table header if further information is provided in the table footer, e.g. superscript letters.

L193ff: It is customary and uniform to only write p<0.001 for all instances where it is < 0.001.

L200: Where those interpolations used for both time-series? Could you provide a regression estimate without using the interpolation as well, to provide further context on its influence on the overall model-fit?

L204: The quality classification scheme is finally mentioned. Please provide it in the methods and at the first mention in the MS as well.

L265f: The subordinate clause may be missing a verb. Please consider revising.

L243ff: Figure 2 is missing proper paneling and the panel C notation is converted to a copyright sign. Please revise for the final submission

L283: “massive” may be considered colloquial

L297: Please add proper notations in the Figure legend for phosphorous.



309: If an abbreviation is introduced – in this case ES – then please use it throughout the text.

L.301ff: Please add the timeframe that the basin plans refer to, e.g. 2nd RBMP (2012-2015). Because it is confusing if in the first paragraph, the ES is shown to be high in Greece, whereas in the 2nd paragraph it is noted that 15 out of 18 rivers have below good ES.

324ff: The examples given where the Nitrate Directive has been applied, do they also coincide with nitrate-load reductions?

338: “started to rapidly increase”

348: “receiving surface waters”?

350: a challenge lies in sth.

350: An abbreviation follows in parentheses after the fully written wording. Also, will this abbreviation find another use in the MS? If not, there is no need for another abbreviation in this abbreviation-overloaded MS.


L 364 – 368: This sentence has grammatical errors and is hard to understand. Please revise. Also, previous paragraphs were discussing the impact of WWTP implementation, then the impact of polluting industries is elaborated and now the paragraph revisits the topic of WWTPs. I would consider reordering the Discussion here.

368f: Were there other instances were such drastic changes in their locale makes the interpretation of the ES and physico-chemical data unreliable?

384: Why should action be taken primarily in Bulgaria and Turkey? Are the main point sources expected there? If so, please name them and provide a reference.

L.383 – 394: the section requires references

401: Why is the situation alarming? Because of the ES estimate, if so, please name it and/or reference the Table.

448f.: If these personal judgments regarding the “suitability” of participating institutions is to remain in the MS, then reasons need to be given, otherwise such personal statements without proper referencing or discussion have not place in the MS.

457: PoM has already been introduced and used throughout the MS.

458: Why is “Community” capitalized and the following nouns are not? Is this correct?

470: “alone” = only

478ff.: I think Chapter 4.2.2 is well-written and informative.

564: Can the authors give an example why they think this? I think it is an important statement, because chemical pollution is one key-driver of ecosystem impairment.

566ff.: The conclusion is well-structured and concise

Author Response

Thank you for your constuctive comments. Our replies are attached

Author Response File: Author Response.docx

Reviewer 2 Report

Skoulikidis and co-authors present the chemical-physico quality trends of eighteen characteristic Greek rivers and the recent evolution of their ecological status with the aim of assessing the implementation of WFD related environmental policies in Greece. The outcomes are interesting and can contribute to advancing our knowledge in preventing and counteracting water quality degradation in areas suffering from multiple anthropogenic pressures. The manuscript is well structured and the methods are soundly presented. However, my main criticism concerns the following points:

- as it stands, the paper reads like a regional technical report dealing with the achievement of the WFD goals in surface waters, especially in the paragraph describing the Results. The paper includes too many figures and tables. I suggest reorganizing the data presentation, maintain in the main text only the main outcomes and move to Supplementary Material the other material. Consider also to combine some figures together in multi-panels figures. I think there needs to be a partial rewrite (and partially shorten) of the discussion to convert the manuscript into a more interesting scientific paper.

- the authors should relate the river quality trends to the temporal changes of anthropogenic pressures in the basins (e,g. the quantification of N and P loads from diffuse and point sources).

- a deeper and speculative interpretation of the presented data is needed, in a way to better evaluate their spendibility for practical application in management programmes of agricultural watersheds.

Specific comments.

Line 17: Not clear what you mean with "riparian countries". Maybe "adjacent countries"?

Line 52: How did you chose the representative rivers investigated in the present study?

Line 73: Is livestock a relevant pressure in Greece? And I think also tourism may affect water quality.

Line 78: Please remove the hypertextual link.

Line 119: Please describe how you obtained the equation relating TP and PO34-.

Line 147: Please consider moving Fig. 1to the Material and Methods section (paragraph 2.1 Study Area).

Table 1: Add the source of land use data.

Author Response

Thank you for your review. You may find attached our replies.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The authors took time and effort to address all my comments in a thorough manner, thus I feel confident that the submission is now ready for publication

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