Dear Authors,

The paper proposes a new routing scheme based on the classical WFIUH approach. The topic has been appreciated by the two referees, and by Dr Martinez who give an additional valuable review. However, the main issues raised by both referees and Dr Martinez is that the authors should make a further effort to highlight the originality of the work and clarify the methods used and the applications, in order to increase the impact of their study. I think all reviewers made valuable suggestions in this regard:
i) Extend the literature review, and discuss the originality and the novelty of the approach in comparison to existing methods.
ii) Compare the conceptual representation of the model and the physical processes, especially the effect of grid size when moving from 20 m to few km. What does mean “perfect scaling”?
iii) Explain how the model runs at the hillslope level before downstream aggregation. If needed, please add additional figures in order to show processes and pathflows.
iv) Analyse the spatial distribution of rainfall and justify the methods used for the spatial interpolation.
v) Results are only shown on two flood events on only one basin. How these results can be useful for applications on other basins and/or other events? What are the limitations of the method developed function of the basin characteristics (DEM, soil, landuse), the importance of the main hydrological processes, the input data, the spatial distribution of rainfall, the model parameters, etc. Additional applications in various hydro-climatic conditions will help the analysis.

In general this paper offers an interesting contribution for streamflow routing in large-scale hydrological. The paper will be reconsidered after major revision. The authors must give a clear and convincing response to each of the points raised by both reviewers and by Dr Martinez. Please highlight clearly what you changed in the revised manuscript, so the reviewers are able to assess your changes.

Kind regards,

Roger Moussa

Dear Dr. Piccolroaz:

The manuscript has been strongly improved. I am pleased to accept " HYPERstream: A multi-scale framework for streamflow routing in large-scale hydrological models" for publication in Hydrology and Earth System Sciences.

I thank you for submitting your best work to Hydrology and Earth System Sciences.

Sincerely,

Roger Moussa