Dear authors,

I thank you for the reply to the reviewers and encourage you to submit a revised version of your manuscript. I think special attention should be paid to issues pointed out by the reviewers such as:
- a better clarification of the differences between the skill of System 3 and System 4: could you provide some evaluation carried out (by yourselves or others) on the main differences between these two systems? Could you also provide a comment on how this could (or could not) affect your evaluations? I think it is not enough to say that System 4 was not available in the beginning of the project to justify its use.
- the clarifications on terminology (as extensively pointed out by referee #2)
- review the use of so many tables (use supplementary material if possible)
- consider taking into account other scores such as the CRPSS as proposed by referee #3. This could improve your conclusions. If not, please justify it.

Thank you very much again, and I am looking forward to receiving your revised version.

Best regards,
Maria-Helena Ramos.

Dear authors,

I would like to thank you for addressing the reviewers’ remarks and providing the revised version of your manuscript.

I think you have successfully addressed the main remarks and suggestions made by the three reviewers and have improved your manuscript. I consider that there is no need for further review by the referees and the paper is suitable to be published in HESS. However, I have a few very minor remaining issues that I would like to be clarified before finalizing the manuscript for publication. They are listed below:

- Page 3, line 3: please, consider indicating if the past study referenced here concerns the same “20 large rivers of the world” considered in the paper (as requested by Reviewer #2)

- In the Introduction, I just saw the lines introduced on Page 3, lines 33-35, to clarify the choice of the 20 river basins of the study (as requested by Reviewers #1 and #2). However, it seems that the request of Reviewer #3 on “a better support of literature in the Introduction” is not addressed, although the authors said in their “reply to reviewers” that they would “include these [references mentioned by the reviewer] with other references in [their] introduction”. Could you please clarify why this was not done or introduce the appropriate references in the Introduction?

- Page 8, line 26: please mention explicitly that the tables are provided as supplement material.

- Sections 3 and 4: some parts in the discussion of the results (Section 4) could rather be presented in Section 3 (presentation of the results) as they are not including discussions. In this sense, I missed a discussion about the meteorological forcing uncertainty versus total uncertainty, which was presented in the comments by reviewers (notably Reviewer #2). Could you please justify why this issue is finally not treated in the paper?

These few remarks above do not compromise the value of the paper, but I would like to hear from the authors about them.

Best regards,
Maria-Helena Ramos.

I thank the authors for the final reply and revised version. I consider the authors addressed well the comments provided by the reviewers and my final comments as Editor. Therefore, I recommend this paper for publication in HESS.