Dear Dr. Rudell,

After reading the discussion I am pretty sure that I was right in accepting this opinion paper – simply because of the nice debate. I am grateful to both reviewers, because they accessed your manuscript in a very critical and yet very constructive manner. Given the nature of your reply, and your professional attitude, I am optimistic that revised manuscript will at the end of the day become a nice and helpful contribution to HESS.

I guess the key is, as you outlined yourself, to better explain from the beginning that this opinion is not targeted towards the hydrological expert but to scientists and managers from close communities, which use the catchment system as a part but maybe not the essential part of their system (and their science). In this sense I agree that a too much rigorous treatment/definition of scales might be contra-productive. Yet, as HESS is a hydrological journal, I think the revised manuscript needs to provide a balanced compromise here, to please also the hydrologists which read the manuscript. I also very much like that you keep the referencing small, as an opinion paper is not a review. Given the core idea of your paper, which is to stimulate the ’non-hydrologists’ to be more rigorous/thoughtful about their water use estimates, I think the paper needs to refer to a few selected key studies in this area. This is to assure that the interested readers (the non-hydrologists) can move on from your work, maybe to improve their future practice? In this context I think that reviewer 2 made the very valuable point that the case of the US, though the US is large, is maybe not general enough for such an opinion.

Best regards and I wish you success with the revision process,

Erwin Zehe

Dear Dr. Rudell,

I very much apologize for my delayed assessment of the revised version of your work. After reading your article, the assessment of reviewer 3 and reviewer 1, I am convinced that your paper provides a nice and timely reflection on the status quo of collecting water consumption data and the dilemma we face in the respect how helpful those are for managers and policy makers. While I agree with reviewer 1 that this is not too much of a surprise for a well-trained hydrologist, I see that these points might be very informative for the former mentioned groups. And the (sad) fact is that it is those who decide on action (including the implementation of the planetary boundary concept, that has been criticized by reviewer 1 in another opinion published in HESS.)

Though I highly appreciate the detailed critique of reviewer 1, I thus decided to follow the recommendation of reviewer 3 and to accept the work after minor revisions. These should address the points made by reviewer 3 which I regard helpful and valid.

Best regards,

Erwin Zehe

Dear Dr. Ruddel,

I am very pleased with way you addressed the comments of reviewer 3 and I see now reason to further hold the manuscript back from publication.

Best regards,

Erwin Zehe