I reviewed the manuscript by Sivelle et al. In this manuscript, the authors present the improvement of a karst modelling platform and show an application on two case studies in France. While this work could have potential for advancing karst modelling knowledge, I found that as is, the manuscript suffers from flaws that limit the understanding and the appropriation by readers.

Namely, I would like to mention:

• The manuscript structure
• The choice of the HESS journal and of submitting this manuscript in the Research article category
• The lack of comparison between the model structure and results, and a previous version, to show the “Improvement of the KarstMod modeling platform for a better assessment of karst groundwater resources », as we could expect from the manuscript title.

Altogether, this makes me think that there is a need for making choices, possibly conjointly with the journal editor:

• Should this manuscript remain a Research article in HESS? In that case, we need clear research questions, a thorough comparison of the “new” model against the “old” one.
• Should this manuscript be limit to a modeling platform presentation? In that case, the article could be submitted to GMD instead, and some of the platform features be further presented.

I cannot make that choice for the authors and I will not recommend any of these two choices, as I think that the authors (providing some further work) can reach both objectives.

I attach to this general review an annotated pdf version of the manuscript with “on-the-fly” comments. This pdf contains both general comments, whose main points I summarised here, but also some more specific questions or suggestions.