Dear authors

you received high quality and detailed reviews to which you also provided detailed answers. Thanks to the referees and you for this discussion phase. To me the most important is the better highlight the added value of this work and embed it in the vast amount of literature on Lake Urmia. Also some more details on the model and model performance is required.
The paper needs to go in full review after resubmission.

I look forward receiving the revised version in due time
Kind regards
Thom

Dear authors

thanks for your patience as it has taken too long. Apologies for that.
You received two new reviews, one minor revisions but with some critical points and one rejected (with extensive review). Both reviewers agree the manuscript is really too long, the groundwater aspect of Lake Urmia (lake-groundwater relationship) should be discussed much more in depth and the model set-up, assumptions and uncertainty need more attention. This could mean the manuscripts will be even longer. See some suggestions to shorten it below.
A formal uncertainty analysis is not required for me (as requested by reviewer 2), but some more quantification and discussion as requested by the second reviewer needs to be included.
Having gone through the paper I do want to stress I think editorial or only textual changes are not sufficient, I recommend to have a fresh look at the current manuscript and bring in some more focus (choice of results to present and discussion and decide which less important results should be presented in supplement only).

The revised version will go in review once more before final decision of possible publication is made. Please provide in-depth response to the reviews and submit also a track changes version of the resubmitted manuscript.

I look forward receiving the revised version of you rmanuscript
Kind regards
Thom

Here I humbly make a few suggestions for the authors to consider. Could you reduce the introduction, and see whether the method section really needs all info? I could imagine that the well-known Watergap model(s) could be summarized in terms of Urmia application only (more, extensive info in supplement). For me, the main aspect (novelty) of your article seems using the comparison of calibrating using RS without and with ground information, so keep that in main text but bring all short references to your input data to the supplement as well.
The results section is very long whereas the discussion is shorter. Typically, one would like to see the reverse. In stead of giving all correction parameters and time-series, you could try to highlight 1-2 results (and present rest in supplement). Furthermore, quite some paragraphs in the results section have discussions. Please re-evaluate whether these parts could not be combined in the discussion.

Note, section 3 consists only of 1 subsection (3.1).

Dear authors

our apologies for the long duration of the review process. One referee needed some more time.
Both referees agree the paper is improved a lot and methods - concepts are well explained. However, both referees are also critical on the interpretation of your own results and especially on the discussions currently in literature on the Urmia lake drying causes. I do agree with the referees that interpretations and discussion should be extensive and complete and take into account various views.
Please respond in detail to the referees' reports and submit a revised version of the paper including a track changes version. I will review the paper and your responses before considering publication.

I look forward receiving your revised version of the paper
Kind regards
Thom Bogaard

Dear authors

thanks for the detailed responses to the referee reports and the revisions in your article. I think this paper is an important and well documented contribution to the scientific discussion on the Lake Urmia drying. Reading the discussions I guess it will also not be the last contribution.
I thank the authors for their patience in this longer-than-normal discussion in HESS and I look forward to continued scientific research unraveling the Lake Urmia hydrology building on this important contribution.

Thanks for having chosen HESS as the journal to publish and discuss openly your research and success with your future research.

Thom Bogaard