Dear Dr. Kumar,

Thank you for your interesting manuscript. Your paper has been carefully read by three referees. All of them find your paper well suited for HESS bus suggest a number of corrections/modifications which need to be carefully considered before publication.

The authors are therefore invited to prepare a author's response which includes a revised version of the manuscript indicating all changes. The revised version shall address all points raised by the referees.

On concern of the second referee (that was not fully addressed in the responses so far) was why to use an empirical approach to calculate the SPI, when a well-established and widely accepted methodology (based on fitting a theoretical distribution function) exists. Although I think this point is only of subordinate relevance for the scope of your study, I share the concern of the referee. Proposing a new approach without carefully evaluating its merits and possible pitfalls relative to a standard method would be dangerous, but I understand that this is likely not the scope of your paper. Authors should therefore clarify in the MS that the approach will likely not have the full skill of the standard method, but is deemed suitable to get a sufficient approximation on a regional scale.

I also share the view of this referee that the role of evaporation is so obvious that one would tend to use the SPEI rather than SPI for assessing hydrological impacts. I acknowledge that the scope of the paper is on a different index, but at least a rough indication should be given (either from additional analyses, or from literature) how far using an index which integrates evaporation loss would make atmospheric drought indices a suitable indicator for groundwater drought.

I would also add one comment, that the methodology of assessing the agreement between meteorological and hydrological drought indices is not completely new. It was recently used in a similar context, for assessing the link of SPI and other atmospheric indices to detect low flow events. Because of this similarity a citation to that study would be appropriate: Haslinger, K., Koffler, D., Schöner, W. and Laaha, G.: Exploring the link between meteorological drought and streamflow: Effects of climate-catchment interaction, Water Resour. Res., 50(3), 2468–2487, doi:10.1002/2013WR015051, 2014.

I am looking forward to receiving your revised manuscript.
Kind regards,
Gregor Laaha

Dear Dr. Kumar,

I am pleased to inform you that your manuscript
"Multiscale evaluation of the standardized precipitation index as a groundwater drought indicator"
has now been accepted for publication.

We appreciate the efforts you made in responding the reviewer comments and revising the MS. I trust that the resulting paper can be a significant contribution to a timely and relevant research field of hydrology and earth system sciences, and HYPER-Droughts in particular.

Best wishes,
Gregor Laaha