Dear authors,
thank you for considering the referee's suggestions for clarification and correction. Your manuscript has been substantially improved. Attached you will find the pdf of your revised manuscript with a few annotations re- typos and some points that need further clarification.
Moreover, I have one specific remark relative to section 2.4. (and that also impacts the discussion/conclusion of your manuscript). There seems to be a confusion around assumptions and hypotheses. Section 2.4. is supposed to formulate the working hypotheses that will be followed by a test set-up, implementation of the experiment and further evaluation of results (with acceptance/rejection of the hypotheses). When stated, the hypotheses should also be followed by what results/observations are expected re- acceptance/rejection of the hypotheses.
As it reads now, section 2.4. provides assumptions, rather than hypotheses. You may reconsider this part and adapt accordingly for further clarification, also in the discussion/conclusion section.
After these minor changes, your manuscript will be ready for final processing with a view to publication in HESS.
Best regards,
Laurent Pfister

Dear authors,
following up on the revised version of your manuscript, I am pleased to accept your contribution for final processing and publication in HESS. Prior to that, I would invite you to correct for a very minor change/correction that should be implemented in the following section:
Page 12, line 35 - suggested text:

The dictionaries Δ for both impact models 35 use an impact velocity Uimp = 1 ms-1, the material is granite and a GSD is simulated according to Recking’s procedure (Recking, 2013), where D84 = 2.D50. When comparing the shapes of both simulated PSDs, shown in Fig. 10a., their respective frequency peaks fpeak are nearly identical. Likewise, the slopes of the spectra are found to be quite similar.

In the current version this paragraph remains difficult to read - there also seems to be a comma that should be replaced by a full stop.

Many thanks in advance for considering the changes proposed above for your final manuscript.

Best regards,

Laurent Pfister