Dear Authors,
I do thank you for the detailed authors ‘ replies, where you address the constructive comments made by the Referees.

I believe that, even if the proposed approach for studying flow duration curves, based on the empirical exploration of the distribution of daily data, is certainly not new (as the Authors themselves acknowledge), the application to such a large data base (conterminous United States) is of sure interest for a very large audience of researchers and operational hydrologists.
In particular, I was wondering if you may consider submit it to HESS as one of the new types of manuscript proposed by the Editorial Board, i.e. (see http://www.hydrology-and-earth-system-sciences.net/about/manuscript_types.html)
“Cutting-edge case studies report on case studies that require (a) broadening the knowledge base in hydrology as well as (b) sharing the underlying data and models. These case studies should be cutting edge with respect to the quality and diversity of data provided, the soundness of the models employed, and the importance of the study objective. Peer reviews of a manuscript of this type will additionally evaluate whether this case study points out challenges for hydrological science and/or accurate/appropriate/innovative design and execution of challenging experiments. The data and models used for the article have to be made publicly available through an open data repository or as a supplement.”
I confess that I do not know exactly how the distinction in the manuscript type is managed, but I refer you to the Editorial Office for instructions.
And I would warmly suggest also making the data base publicly available, if possible, because it would definitely be a distinct point of strength for the paper if such a database was available for the readers.

In your replies, you already identify a number of points that you intend to modify in the work in order to address some important criticisms raised by the referees and I therefore invite you to modify the paper according to their suggestions and following the lines you highlight in the replies.

In particular, I do agree with your decision to remove the analysis on the “Regional case studies” (section 4), that was indeed not clear, and also to remove the direct comparison between the MA-FDC’s and the POR-FDC approaches, given their important differences.

I also fully support the Referees’ suggestions on the need to deepen the presented analysis, and in particular i) adding a discussion of the seasonal variations and ii) adding considerations on the link between climate/catchment characteristics and the fit of the distributions.

I look forward to reading the revised version.

Elena Toth
HESS Editor

Dear Authors,
I do thank you for having deeply re-structured the paper and changing the type of manuscript to “Cutting-edge case studies” according to our suggestions, since, as I have already written, the application to such a large data base (conterminous United States) is of sure interest for a very large audience of researchers and operational hydrologists even if the applied methodology is certainly not novel.
I have asked to only one of the expert Referees of the discussion phase to upload her/his comments on the revised manuscript.
You have addressed the majority of the comments raised by both me and the three referees, as already indicated in your replies, i.e. removing the ungauged basin application and also the direct comparison between the MA-FDC’s and the POR-FDC approaches.
I do regret that you have, instead, decided not to add (as you intended to do, according to your replies in the discussion phase) the analysis on the seasonal influence. And I also believe that you might have gone in more depth into the considerations on the link between climate/catchment characteristics and the fit of the distributions in different US regions that you have added in Section 4.3.
On the other hand, we understand that such analyses, in order to be carried out thoroughly, so to be able to provide additional useful insights on such an important issue as the variability in space and time, would require a substantial amount of work and will probably also ask for a more comprehensive theoretical framework, thus going perhaps beyond the current scope of this ‘cutting-edge case study’ paper.
Once you will have made the minor corrections asked for by Referee #3, the manuscript should therefore be ready for publication.
I do thank you for having submitted your interesting work to HESS.
Best regards,
Elena Toth
HESS Topical Editor