Dear Hannes,

Apologies for taking some time to complete the review of your paper. Both reviewers supported publication of the paper subject to minor revisions and I am also of the opinion that a description of WaterGAP is a substantial contribution to the community.

A significant difference of opinion exists regarding the inclusion of section 7. I agree with Dr Coxon that that paper could stand on the model description plus the evaluation presented in section 6 and that this would provide a shorter and more focused paper. That said, the section does provide new and relevant information that pertains to the purpose of undertaking the modelling, and I'm convinced by the argument that this information would often be of interest to the reader. Therefore I am happy to accept it be included. Furthermore, the paper is long, but will always be long due to the number of model components.

Thank you for providing an update on the code availability in the response to reviewers. If the situation has improved since the revision please edit the code availability section. Please also not the GMD encourages updates to model description and I hope that code version archives can be included with any such publications.

Best wishes,
Jeff