At this stage of the review process, authors are only asked to answer to the reviewer comments and no revised manuscript is required yet. Therefore, my summary and decision is made solely on looking at the files containing the authors’ response.

Two referees thoroughly evaluated the manuscript, and the authors answered in detail to the comments. The main points were:

1) more information about the methods is required
2) more information about the study site is required (lakes, hydrogeology)
3) improve data interpretation of 14C
4) consider conditions of evaporation during infiltration (experiment vs. recharge areas)

In addition, I want to emphasize that the authors still need to put the results into a broader context. My initial request before accepting the manuscript for HESSD was followed in the introduction. However, in the discussion and in the summary/conclusion results should also be put into a broader context too (e.g.: What has been found about water sources in other, similar desert regions? What can others learn that e.g. want to identify water sources in deserts at the other side of the world?).

These main and all other comments require some substantial rewriting of the manuscript according to the given answers. I ask the authors to carefully go through the text and -if not done yet- address my additional comment (broader context). A revised version of the manuscript can be uploaded and, I am happy to then reconsider the manuscript for publication after these major revisions were done.

The two initial reviewers were happy with the answers to their comments and the changes of the authors to the manuscript. Therefore, I accept the manuscript for publication.