On the basis of the comments provided by the two reviewers involved and the authors' replies to these, I do think that the manuscript does not poses as a significant breakthrough. However, it shows some merits, as outlined by the reviewers. As such, I am willing to concede the authors a very last opportunity to clarify the uniqueness and strength of their contribution through the implementation of a set of major revisions, along the lines suggested by the reviewers. I must be clear that it is not my intention to discount any of the critical comments raised during the review process and that, in case the authors decide to submit a revised manuscript, the latter will undergo an additional thorough review process. Acceptance of the manuscript will then be strongly conditional to the resulting quality of the revised work.

The manuscript is a revised version of a previously reviewed work. It was intended as a Technical Note. The previous assessment resulted in a set of major revisions to be implemented. I was very clear on the outcome and these were supposed to be chiefly associated with the observation that the manuscript did not provide a significant breakthrough to be considered for publication in HESS. While I actually like the manuscript, I can see the point of the most critical reviewer who provided his/her services during the previous round of reviews. In response to these points, the authors did not change too much the essence of the work and limited their revisions to adding a few details of the mathematical developments (these were also in part requested by Reviewer No. 1). This leads me to the current round of reviews, where the most critical Reviewer was asked to provide his/her view on the revision. Unfortunately, the Reviewer feels like the authors did not address adequately the important issues he/she raised. I studied the manuscript and, to be fair and without entering into an unfruitful discussion, while I do think that the advancement with respect to the current state-of-the-art is not markedly high (I also note that this work is part of a sustained series of works associated with analytical solutions performed by some of the co-authors and I would not like this to become a continuous source of submissions associated with analytical solutions), I can see the merits of the work. As such, I do think it can fit the purpose of a Technical Note and it is with this spirit that I can recommend publication so that a discussion can be made in the open.