Dear Dr. Gnecco:

Thank you for submitting "A dimensionless approach for the runoff peak assessment: effects of the rainfall event structure" to HESS. Based on the 2 reviews of your manuscript and my own assessment, I find that your manuscript needs substantial revisions before it can be considered for publications.

I think the 2 reviewers have served you well, with many constructive comments.

As already highlighted by both reviewers, a strong limitation of this paper is that it is unclear which aspects of current research it is trying to advance. I understand that the work is about predicting the impact of the rainfall event structure on the peak flow rate. However, it is unclear what has been done before on this subject, and what are the limitations of previous studies which this particular work is attempting to address.

Reviewer 2 notes that the paper sounds uninteresting, which in my opinion is due to the fact that it lacks the structure that can make a research work interesting. It is not sufficient to present a methodology and apply it. One needs to motivate it, and to show that it works better than other state of the art approaches. Otherwise, why should one use it?

There is considerable work to be done in the introduction, to describe more specifically state of the art approaches, their limitations, and identify the paper objectives. If I read that the first objective of the paper is “to define a structure relationship of the rainfall event in terms of a simple power function” I wonder why this is interesting, if this has already been done, what are the challenges associated with this objective. If you can’t defend why pursuing this objective is interesting, then you should look for other objectives.

The real data case study is very limited. I expected that a paper that explores “peak flow rate values, which are subject to a very broad range of climatic, physical, geomorphic and anthropogenic factors” tests the proposed methodology on a broad range of climatic, physical, geomorphic and anthropogenic factors. Instead, the method is applied to one catchment, and I did not find a clear comparison between predictions and observations of peak flow rate values. I would expect a case study that compares predictions and observations of peak flow rate values in catchment with contrasting responses, to show that the method is able to capture the differences in catchment behaviour.

When reading the methodology I found it difficult to understand where it is going to lead. I recommend to state first why you do something, and then how you do it. This could contribute to clarify the linkage between the given sequence of steps.

As a last minor comment, I found the wording “rainfall event structure” poorly defined. I was surprised that after speaking of rainfall event structure, a constant hyetograph was used.