Climate or land cover variations: what is driving observed changes in river peak flows? A data-based attribution study

De Niel, Jan; Willems, Patrick

doi:https://doi.org/10.5194/hess-23-871-2019

Articles | Volume 23, issue 2

https://doi.org/10.5194/hess-23-871-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/hess-23-871-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 23, issue 2

Research article

|

14 Feb 2019

Research article |

| 14 Feb 2019

Climate or land cover variations: what is driving observed changes in river peak flows? A data-based attribution study

Jan De Niel and Patrick Willems

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Final revised paper (published on 14 Feb 2019)
Supplement to the final revised paper
Preprint (discussion started on 17 Jul 2018)

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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RC1: 'Review on "Climate or land cover variations: what is driving observed changes in river peak flows? A data-based attribution study"', Anonymous Referee #1, 02 Aug 2018
- AC1: 'Reply on RC1', Jan De Niel, 10 Aug 2018
RC2: 'Review comment', Anonymous Referee #2, 03 Aug 2018
- AC2: 'Reply on RC2', Jan De Niel, 10 Aug 2018
RC3: 'Comments on Climate or land cover variations: what is driving observed changes in river peak flows? A data-based attribution study', Anonymous Referee #3, 11 Oct 2018
- AC3: 'Reply on RC3', Jan De Niel, 12 Oct 2018

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

ED: Reconsider after major revisions (further review by editor and referees) (17 Oct 2018) by Nadav Peleg

AR by Jan De Niel on behalf of the Authors (18 Oct 2018) Author's response Manuscript

ED: Referee Nomination & Report Request started (19 Oct 2018) by Nadav Peleg

RR by Anonymous Referee #1 (16 Nov 2018)

Suggestions for revision or reasons for rejection

I have read the manuscript entitled "Climate or land cover variations: what is driving observed changes in river peak flows? A data-based attribution study" for the second time. I still think the topic of the manuscript is suitable for the journal, and o great interest. The authors tried to address most of the comments of this reviewer (however, some comments were not considered or worked enough), nevertheless, in my opinion the text should be edited by a native English Editor for improving readability an understandability, before being published, as sometimes is difficult to follow the text.
Addittionally I still have some concern on the text that I list below:
1. Introduction
- I still think there are a lot of references in the introduction and little content on them. The authors say they prefer to leave it as is, however, for me it does not make sense to refer to many other paper and not mention some ideas or conclusions of those researchers (paragraphs 3 and 4 of the introduction). In fact, the authors do comment on other authors findings on the next paragraph (number 5). In my opinion, this should be revised before publication.
- P2 L10-13: Do the references follow any order?
- P1 L8: the objectives should go at the end of the introduction section, so that they can be deleted from this paragraph.
- P2 L14: “do not aim to attribute the changes to the specific type of changes that occur”. Please clarify this sentence.
- P2 L15: “mainly because of the heterogeneity of hydrological responses. What do you refer to?” examples?
2. Study area and data
- P2 L37-38. “The Southern part with silty soils has low hills op to 150 mTAW. The maximum height is 288 mTAW in the South East.” If hills are up to 150 m how can maximum height be 288 m?, please clarify this sentence .Change op by up .I do not think it is necessary to repeat all the time TAW, it makes reading more difficult.
- P3 L3-8. In this text the authors give general average data for the study area. However, they give specific data of ETR for years 1980 and 2010, a general average data, would be more appropriate to be compared with the rest of data given here.
-P3 L9: “Twinty” should be twenty.
3. Methods
- About table 1 and periods used to estimate peak-flow anomalies. How can influence the use of different periods in the estimation of those anomalies?. Shouldn’t the same period for all catchments be used? Natural climate variability can be high from one year to other and it can strongly influence hydrological response. The authors should address this question and justify the use of different periods.
- Figure 4 was added in order to better explain methodology. However, some more explanation on the figure is needed in the footnote in order to understand it. What are figures a) b) c)….? This could be a general comment for figures and tables, as their foots are sometimes scarce on content and hardly explain what the figure or table means.
- On a previous comment: “In section 3.3. The consideration of characteristics other than climate and land use in the analysis is interesting; however, the authors should justify the inclusion of catchment characteristics on the analysis and the selection of the included characteristics. Why those and not others? The general description of the area may help on this, if the selected characteristics are the ones that show higher variability in the area...” The authors response is: “Soil texture taken into account as there are significant gradients in Flanders and thus differences amongst the various catchments: e.g. L01_491 has mainly a loamic soil texture, whereas L07_286 is mainly siltic, etc. Slopes should definitely be taken into account, as this has a known/obvious impact on rainfall runoff. Similar for the river density (ratio of river length over catchment area). Catchment area is often linked to peak flow sensitivity, and thus was initially taken into account for this study. However, later in the study, this variable is discarded, based on statistical considerations. See also the start of the discussion (P6L21). Note that these characteristics also come back in the concepts of the hydrological model WetSpa when assigning runoff coefficients.” I agree with the answer, however, I don’t see any of it in the new text of the manuscript.
P5 L3: “However, we assume the area of Flanders to be homogeneous with respect to the considered climate data” What do you mean? only one climatic series is considered for the whole area? Or, are you referring to weather types? Please clarify in the text, How can this affect results? I mean, considering it as homogenous?
P6 L34-37: “Further, for the Zuunbeek catchment at SintPieters-Leeuw, increased peak flow anomalies are observed as from the middle of the period. This is due to the extreme flood season in the winter of 2001-2002 where 7 events were observed with peak discharges exceeding 6 m3/s, corresponding to empirical return periods larger than 1 year, based on data between 1978 and 2016. We will add the above paragraph in the Results section of the revised manuscript.” This makes me think about two previous questions. Is the period important?, can, in this case, different periods be used for anomaly estimation? Can the climate really be considered homogeneous in the study area?
P7 L2: please include “river” before “density”.
P7 L3-11. The authors mention here the use of Wetspa model. However, nothing about it was mentioned before in the methodology section. Further, this reviewer does not understand very well the inclusion of that model. It seems the authors try to justify or explain the results obtained in their research with the results of a model that they do not explain how has been calibrated and applied in the study area. The model was applied by the authors in the study area? In any case, is it really necessary to include this information in the paper? If so, the authors should explain a bit more on its application and justify the need of it. In addition, the manuscript already has lots of figures to add new ones. This part of the section is confusing for this reviewer. “Using runoff coefficient as a proxy for peak flow anomalies”, the authors should include some reference for this.
Section 4.2, effect of single drivers.
Firstly slope and texture are mentioned. However, there I no discussion on them. The authors only try to justify their findings on the use of the Wetspa model.
Second, the climate system. Little is also said about this. The existence of a negative correlation between some weather types, could be related with the fact that, when one increases the other inevitably decreases? I might be wrong, however, this paragraph on climate system does not give many information and results confusing.
Finally, when considering land use, the authors only consider urbanization. If this is their main goal in the paper, it should be clear from the title and the introduction.

4.3 Interaction effects. This reviewer really appreciates the effort made including this new sub-section.
In figure 12 c) only one slope rage is considered, so it is difficult making the same comparison as in the other figures.
Here, I have the same questions on Wetspa model that I had in section 4.2.

Others:
P2 L26 and P3 L21. As suggested by one of the other reviewers before, brackets should be deleted and the authors should decide if they want to maintain or delete the words “relatively” and “main”.
P3 L21-24: As suggested for the introduction section by one of the other reviewers before, “Sect.” should be replaced by section. Please revise all the text in this sense.
There is no need for writing “+” signal before increasing percentages, specially, when it is clearly said in the text that the trends are increasing. So please delete those signals all over the text and abstract: For example. P1 L22: “precipitation might increase with +50 % in winter…” should be “precipitation might increase a 50 % in winter”. Please check also for English correctness.

13 figures can be too many for a manuscript. The authors should try to summarize the information or select the really important ones and publish the rest as supplementary material.

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RR by Anonymous Referee #2 (21 Nov 2018)

ED: Reconsider after major revisions (further review by editor and referees) (28 Nov 2018) by Nadav Peleg

Dear Jan De Niel and Patrick Willems,

Thank you for revising the manuscript and responding to the referees’ reports. Although I find this version of the paper much improved in comparison to the initial submission, I believe the manuscript can, and need to, be improved before I can consider it for publication. Please note that most of my comments below and the comments from the two referees mainly refer to the presentation quality.

- Text editing are needed. There are typos and grammatical errors that should be corrected (some mentioned by the reviewers).
- Introduction section. I agree with the comments made by Reviewer #1 - instead of giving a long list of references please elaborate and explicitly refer to the contribution of the papers mention to this study. In general, the introduction section needs to explain more in depth the climate and land cover drivers.
- There is a disproportion between the length of the text (8 pages) and the number of figures (13) and tables (3). I think 4-6 figures and 1-2 tables should be sufficient to present your study properly. Please consider merging some of the figures (for example, 12 and 13) and presenting some as Supplementary Information (e.g. figure 3 and table 1).
- Figure 4. Please added in the figure caption text to explain subplots (a) to (e).
- Please consider having separate sections to present the results and for the discussion.
- Catchments. Sometimes you are using numbers and sometimes names when referring to the catchments. Please be consist. In addition, I suggest simplifying the labels of the catchments, e.g. use simple IDs from 1 to 29.

I invite you to upload a revised manuscript, incorporating the proposed changes and additions, and making any other modifications where you see fit (‘major revision’). The revised manuscript will be sent for the referees for a third round of revision.

I look forward to receiving the revised manuscript.

Sincerely,
Nadav Peleg

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AR by Jan De Niel on behalf of the Authors (06 Jan 2019) Author's response Manuscript

ED: Publish subject to minor revisions (further review by editor) (11 Jan 2019) by Nadav Peleg

AR by Jan De Niel on behalf of the Authors (16 Jan 2019)

ED: Publish as is (02 Feb 2019) by Nadav Peleg

AR by Jan De Niel on behalf of the Authors (04 Feb 2019) Manuscript