Dear authors,

thank you very much for your detailed replies to the reviewer comments. As you have seen, the reviewers highlighted two major points that need to be addressed in detail before your manuscript can be considered for publication.

The first point concerns the estimation of MTTs in our analysis. It is critically asked, if your methods and the resulting interpretation of the results are actually suited to the questions you intend to explore given the data you have available. Although MTT estimates based on lumped, time-invariant convolution integral approaches were in the past frequently used, there was quite some development in the field over the past years. In the light of this progress, I would encourage the authors to at least evaluate their MTT results against the somewhat more robust estimates such as young water fraction as proposed by Kirchner (2016).

The second major point highlighted is that the manuscript itself would considerably benefit from some re-structuring, more specificity and clarifications to provide the reader a better sense of what you are doing, why and what your findings are. Please also make sure that the results are interpreted much more in the context of what was found previously by other authors.

I am looking forward to receiving a revised version of your manuscript addressing all reviewer comments, which will then be sent out for a second round of reviews.

Best regards, Markus Hrachowitz

Dear authors,

the three reviewers generally appreciate your efforts in addressing their previous comments. They think that the manuscript benefited substantially from that. I broadly agree with their evaluation.
However, they also highlight several points that need some further attention. This involves, in particular, the comment of reviewer #1 on the validity of the estimated MTTs and YWFs. I therefore strongly encourage you to invest a little more effort to adequately address these points. I would be glad to see a more robust estimation of YWF based on Kirchner's (2016) method, as suggested by the reviewer.
In addition, please also address in detail the remaining other points raised by the reviewers. It seems that you addressed in the new text the previously suggestions made, but barely in the tables (e.g. showing a table with confidence bounds while stating in the text that these bounds are just a guess is not an acceptable revision).

I am looking forward to receiving a revised version of your manuscript!
Best regards,
Markus Hrachowitz

Dear authors,
thank you very much for addressing the remaining reviewer comments. I think you have done this in a meaningful way that helps the reader to better understand the limitations of the presented analysis.

Before I can accept your manuscript for publication, I would like to ask you to do a few small technical edits:

(1) please rearrange table 5 (and 6) in a way that avoids giving the same information twice (e.g. catchment areas,...) and to add the estimates of young water fraction for each catchment

(2) in figure 3, please make sure to use consistent units: precipitation is flux in the system and needs to be expressed as a rate (volume/time, i.e. in your case as mm/week). Please also discharge to mm/d.

(2) in figure 5 it is difficult to distinguish the endmember contributions as some colors are too similar. please find a clearer color coding. also, i cannot see the blue end member (shallow well (WE.a) )

(3) please make it clearer in the methods section that the EMMA is based on Principal Component analysis

Best regards,
Markus Hrachowitz