Development of streamflow drought severity&ndash;duration&ndash;frequency curves using the threshold level method

Sung, J. H.; Chung, E.-S.

doi:https://doi.org/10.5194/hess-18-3341-2014

Articles | Volume 18, issue 9

https://doi.org/10.5194/hess-18-3341-2014

© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.

https://doi.org/10.5194/hess-18-3341-2014

© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 18, issue 9

Research article

|

03 Sep 2014

Research article |

| 03 Sep 2014

Development of streamflow drought severity–duration–frequency curves using the threshold level method

J. H. Sung and E.-S. Chung

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Final revised paper (published on 03 Sep 2014)
Preprint (discussion started on 03 Dec 2013)

Interactive discussion

Status: closed

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

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RC C6908: 'Review of manuscript titled “Development of streamflow drought severity- and magnitude-duration-frequency curves using the threshold level method” by J. H. Sung, E.-S. Chung, and K. S. Lee', Anonymous Referee #1, 26 Dec 2013
- AC C8001: 'Interactive comment on “Development of Streamflow Drought Severity-Duration-Frequency Curve Using Threshold Level Method”', Eun-Sung Chung, 24 Feb 2014
RC C7379: 'Comment on: Development of streamflow drought severity- and magnitude-duration-frequency curves using the threshold level method', Anonymous Referee #2, 23 Jan 2014
- AC C8016: 'Interactive comment on “Development of Streamflow Drought Severity-Duration-Frequency Curve Using Threshold Level Method”', Eun-Sung Chung, 24 Feb 2014

Peer-review completion

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

ED: Reconsider after major revisions (18 Mar 2014) by Carlo De Michele

Dear Authors

After my personal reading of the manuscript "Development of Streamflow Drought Severity- and Magnitude-Duration-Frequency Curves Using the Threshold Level Method", the reports of the two Reviewers, and your reply to these,

I would like to ask you to take in to account the following suggestions to improve the manuscript.

Major issues:
1) The Authors introduce the concepts of severity-duration-frequency (SDF) curve and magnitude-duration-frequency (MDF) curve.
1.1)However in the Methodology section they did not explain how these curves are calculated, reporting conversely, details well known in literature (like GEV, Gumbel distributions or their L-moments).
1.2) Reading the manuscript, it seems the Authors have calculated empirically SDF and MDF curves. Is it right? This point must be clarified in the text.
1.3) One thing that could improve the manuscript is providing a theoretical law to obtain SDF and MDF curves, like the IDF or DDF curves.

2) Drought is a multivariate event where the variables like severity, duration and intesity of the drought are dependent one from the other. Please clarify this in the introduction, and update the references given with recent works available on this issue.

3) I found several mistakes in the text. Thus I suggest to the Authors to improve the English before resubmitting the revised version of the manuscript.

Minor issues:

1) pag. 14676 line 5 “e.g., a rainfall intensity-duration-frequency curve”. This is not clear. Please clarify otherwise delete it.
2) pag. 14678 line 7 change “variable” in “variables” and “levels” in “level”.
3) pag.14679 lines 11-12, “the ratio ... zc”. The sentence is not clear.
4) pag.14687 lines 11-13, what is SDI? Probably SDF.
5) pag.14697 change “events” with “event”.
6) pag.14696 simplify the figure. Probably you can take out the four boxes (Fixed Q70, ....) from each step because these are repeated identically.
7) pag.14693 Report the units of measure.
8) pag.14701 Report just one legend for the three sub-figures.

Awaiting for the revised manuscript,

kind regards

Carlo De Michele
HESS Editor

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AR by Eun-Sung Chung on behalf of the Authors (27 Apr 2014) Author's response Manuscript

ED: Reconsider after major revisions (04 May 2014) by Carlo De Michele

AR by Eun-Sung Chung on behalf of the Authors (21 May 2014) Author's response Manuscript

ED: Referee Nomination & Report Request started (30 May 2014) by Carlo De Michele

RR by Anonymous Referee #1 (14 Jun 2014)

Suggestions for revision or reasons for rejection

General comments

1. This is a revised version of an article appeared in HESSD; it is acknowledged that the authors have put a considerable effort to respond to reviewers’ comments and revise their manuscript accordingly; yet, a number of corrections are still required, which are listed in the specific comments section below.
2. As for the originality of the paper, in my previous review I was stating: “(1) the severity-duration-frequency (SDF) curve for drought analysis has been proposed by Dalezios et al. (2000); (2) those researchers have used the GEV distribution as the authors of the current paper do; (3) since drought is a slowly developing phenomenon it needs to be analyzed only at coarse time scales (e.g., greater than a month); as a result, daily deficit is of no practical use in drought analysis; (4) a direct consequence of the previous statement is that the use of the proposed MDF curve is not expected to contribute to drought analysis; (5) the approaches used to determine thresholds are known.” The authors responded successfully to all the above. They think that the use of the desired yield threshold is an original element in their work. In my view, this contribution is marginal due to the fact that the use of the desired yield implies some anthropogenic intervention on the natural hydrological system, which, according to Tsakiris et al. (2013), is not related to drought but to another form of water scarcity, namely water shortage; but this leads to invalidating the concept of socioeconomic drought and I will not insist on this. In my view, the main contribution of the paper is the comparative application on the study area of various approaches regarding threshold definition, i.e., its contribution on the knowledge of droughts in the study region through using various threshold methods; of course results on more basins and climatic zones would greatly raise the value of the research presented.
3. Since the Magnitude-Duration-Frequency Curves have been removed from the manuscript, it is suggested to modify the title to read “Development of Streamflow Drought Severity-Duration-Frequency Curves Using the Threshold Level Method”.
4. English has to be further improved.
5. The manuscript still has a number of serious weaknesses which are given in the specific comment section below.
6. In view of the above and the specific comments below, the manuscript cannot be accepted for publication in its present form; after major revision it has the potential to be published as a contribution to knowledge of the hydrology of a specific area with a marginal contribution at the methodological level.

Specific comments

1. L 16: General statements such as “which can significantly affect the streamflow drought severity” should be avoided in the Abstract; if the selected thresholds are effectively tested and found to significantly affect the streamflow drought severity, this should be clearly said.
2. L 16 -17: The phrase “The four threshold levels utilized” presupposes that readers know that the threshold levels are four in number; it is suggested to remove “The” to read “Four threshold levels ...”.
3. L 30: The Abstract is left unfinished; no information on the validation of the proposed approach is provided.
4. L 36 -37: The definition “A drought implies a period of time when the supply of water cannot meet its typical demand” is too narrow and suitable only for the socioeconomic drought; it is suggested to remove it so as to avoid confusion.
5. L 37: The statement “Rainfall deficiencies of sufficient magnitude over prolonged durations” is incomplete when dealing with drought phenomena; the spatial dimension is critical; please consider saying “Rainfall deficiencies of sufficient magnitude over prolonged durations and extended areas”; then a comment will be necessary to justify the fact that the areal dimension is omitted.
6. L 58 -62: The definition of the hydrological drought is copied from the Introduction of the paper by Nalbantis and Tsakiris (2009); this requires putting the text within quotation marks and italicizing it; since the number of such quotations within an article cannot be large, these are used only when necessary; while the authors effectively apply this rule later, in lines 72-73, they avoid doing this here and in other cases.
7. L 62-66: The same holds for this phrase which is taken from Tsakiris et al. (2013); it is assumed that the editor can electronically locate all these cases; then it is up to the authors to choose those quotations that are absolutely necessary; the remaining text from other papers should be removed or condensed and rephrased so as to avoid using quotations.
8. L 83: The term “to the variable method” is meaningless; please consider changing it.
9. L 90: The reader will wonder about the need to plot drought iso-severity curves; a brief comment is necessary or the whole phrase should be removed.
10. L 140: The expression “will be studied in the future” is incomprehensible in this context.
11. L 152: I presume that the authors meant “percentile from the FDC”.
12. L 155-156: A verb is missing in the phrase “Specifically, 70% is the percentage of time that the streamflow Q70 is exceeded”.
13. L 159: I presume that by “where to apply” the authors meant “whether to apply”.
14. L 166-167: The argument “because droughts in the region of interest have never been studied” is unclear in this context; please explain better.
15. L 179: The terms “hydrological and socioeconomic demands” induce confusion and need to be defined or removed.
16. L 197 – 200: Symbols f(.) and F(.) are left undefined.
17. L 213: Modify to read “result from the rainfall frequency analysis”.
18. L 218: The term “return period” is known needs no definition.
19. L 251: Is it forest land already mentioned in line 249? If yes, please make the necessary corrections; otherwise, please explain.
20. L 255: It is suggested to remove qualifiers such as “serious” for droughts to avoid confusion with drought class names.
21. L 291 – 293: In this phrase two sentences begin with “because” which is generally avoided due to the confusion it creates.
22. L 300 – 301: In the phrase “the correlation coefficients were calculated” the correlated variables are not named.
23. L 312: The title fails to be fully informative since the probability distribution function is not linked to any variable.
24. L 321: The statement “distributions that use more than three parameters are required” creates confusion since distributions appearing later include three parameters; please consider amending this.
25. L 324-325: What do the authors mean by “This corresponds to Dalezios et al. (2000) for the PDSI and Yoo et al. (2008) for the SPI.”?
26. L 339: What is the “difference ratio”?
27. L 349-353: This material is unsuitable for a “Results” section and should be found in a “Methodology” section; also, comments on results may be added which are missing now.
28. L 361-385: The whole conclusion section needs to be rewritten; as is, it corresponds to a summary rather than a conclusion section; it is therefore suggested to rename the section into “Summary and conclusions”; in the summary part of the section methodological details should be avoided, which is not the case with the current form of the section; last, the conclusion part needs to be enhanced.

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ED: Reconsider after major revisions (26 Jun 2014) by Carlo De Michele

AR by Eun-Sung Chung on behalf of the Authors (16 Jul 2014) Author's response Manuscript

ED: Publish as is (22 Jul 2014) by Carlo De Michele

AR by Eun-Sung Chung on behalf of the Authors (01 Aug 2014) Manuscript