Dear authors,

your manuscript has received three reviews. All of the reviewers, especially reviewer #1, appreciate the effort to combine hydrogeological field work with a modelling study. The manuscript is overall well organized and the figures are clear. Two of the reviewers also raised concerns with the manuscript, specifically regarding the presentation of the model setup for the specific site, choice of model parameters, mesh, location of observation points, representation and discussion of the results. Additionally, reviewer #3 points out that field work and modelling are rather decoupled.

I agree with the reviewers regarding the merit of the study, as well as the potential improvements with regard to representation of the field case in the model, and regarding the model analysis.

You have already submitted detailed replies in your final author comments, making constructive propositions to improve the model and manuscript. They address many of the main concerns of the reviewers, and can be implemented as proposed. In keeping with reviewer #3, I strongly encourage you, in addition, to strengthen further the connection between the field and modelling study and bringing out the novelty of the study.

Please submit the new version of the manuscript with changes highlighted and make sure you responded to all comments by the reviewers. I will send out the new version for another round of reviews.

I thank both the reviewers and the authors for the constructive comments and interactive discussion - I am looking forward to the new version of this manuscript.
Anke Hildebrandt

Dear authors,

Thank you for your revised manuscript which has now been re-considered by two of the previous reviewers. Both reviewers find that the revision is an improvement. Both reviewers find however that the current version of the manuscript still has substantial caveats, which were already commented on in the first round and not addressed appropriately in this revision. In fact, the submitted revision is comparatively minor, given the strong critique of the reviewers on the previous version.

Although both reviewers recommend publication, I find that the current version of the manuscript is too technical and does not meet the standards of a scientific publication (see non-public comments for more detail). In the current form, the manuscript reads like a technical report. This has not changed during the revision, and I am left to believe the technical character of the manuscript is intentional. With HESS being a scientific outlet, the manuscript is in the current form not ready for publication in HESS.

In see two ways forward:
(a) Substantial revision of the manuscript, taking into account all comments of the reviewers (both revisions), strongly connecting the field and modelling study, adjusting the argumentation to acknowledge the substantial environmental heterogeneity and how it affects the conclusions.
(b) Not publishing in HESS and submitting the manuscript to a different, more technical outlet.

In case you decide for option (a) I have added below more explanation in the non-public comments for the author. Please resubmit the manuscript with changes highlighted (since you seem to be working in Word, please use the “Review” tools or “Merge documents” options there, otherwise highlight all changes in-line in only one single resubmitted manuscript). Please also add a letter listing and commenting on the amendments. The new version would have to be a major revision of the manuscript and will form the basis for the final decision.

In case you decide for option (b) you may contact Copernicus or myself for learning your options.

Please allow me to reiterate that I find this a valuable contribution, which would benefit from the revision mentioned in option (a).
Best regards,
Anke Hildebrandt

Dear authors,

Thank you for your revised manuscript. The new version has addressed most of the major reviewers and editors comments. I think it is almost ready for publication, given some small adjustments (see below this email).

I am looking forward to the final version of your manuscript.
Best regards,
Anke Hildebrandt


Specific comments on the manuscript:

In the abstract: Please state explicitly that the numerical experiment considers homogenous soil conditions. Also, please state more explicitly, what is meant with “largest perturbations”, e.g. the enhanced potential for surface runoff.

Fig 1c: The color shading of the upstream area of the drain is confusing. Please correct.

Lines 122-129: This is a good and important part, but currently difficult to read. Could you please rephrase.

Line 348-359: This paragraph is a discussion on the assumptions made in the model. Please elaborate how the homogenous case consists a “worst case scenario”. Also, please phrase your modelling results in a way to make it obvious that they are true for the modelled homogenous case, and phrase the conclusion at the end of the paragraph less generally.

Lines 384-385: Same as above.

Dear authors, thank you for the revisions, which have improved the manuscript such that is now ready for publication. Best regards, Anke Hildebrandt