Thank you for your thorough responses to the reviewers' comments. Because these proposed revisions are fairly substantial, and because I would like you to consider a few additional points, I am recommending that the manuscript be reconsidered after these revisions. I do not, however, anticipate sending the manuscript back out to reviewers. I ask that you revise the paper in accordance with the reviewers' and my comments.

Despite your response to Reviewer 1, I still agree with them that the methodology in your paper is not particularly new. Importantly, I do not believe the main contribution of the paper should be methodology. Instead, I think the main contribution can be (1) insights gained regarding climate change impacts in an arid region such as your study area and (2) insights gained regarding advantages of using a process-based groundwater model in this type of study, as compared to some of the other, less processed-based models or methods that have been used. I suggest you revise the paper in accordance with this alternative view of the contribution of your work.

Below are some additional comments with respect to your responses to the reviewers:

Reviewer 1:
1. In your response to item 3, at the bottom of the 3rd paragraph you state: “In contrast, it can be concluded that this is an inappropriate approach for assessing GW resources impacted by climate change in arid environments.” You need to state why this is so.
2. In your response to item 4, you could point out that while it would be advantageous to use additional GCMs, you are focusing on system response, hence the key contribution of the paper can still stand if using only one GCM.
3. Uncertainty analysis under item 5: Recommend you rewrite your uncertainty discussion to include discussion of how uncertainty in the GCM and in your hydrologic models could affect the observed system response.
4. Under item 10 you mention that full details of the GW model have been published elsewhere, but please make sure you state this clearly in the manuscript. Furthermore, you still need to include at least a short paragraph indicating how representative of the hydrogeologic system the model is, and how you know this. In other words, you need to say something about how good you think the model is and what general calibration results you achieved to demonstrate this.
5. Also under item 10, the entire Qbox section needs citations.
6. Under item 11 the authors proposed insertion still misses the point. “Wetter” does not necessarily mean more floods. Suggest inserting “possibly” before “resulting.”
7. Reviewer comment 11800, 2-5: Authors change is not responsive to reviewer’s comment.
8. Throughout: “couple modeling” is incorrect usage and should be replaced with “coupled modeling”.
9. The revised figure 1 has text in the inset window that is too small to be legible.
10. Response to reviewer comment 11817, 19-20: Authors revised text is still too strong, especially given the uncertainties, including those stemming from not using more than one GCM.

Reviewer 2:
1. Reviewer suggests changing the title, which I agree with because I think the main contribution is not the modeling method, but rather, insights on the system response derived from a process-based gw model. In response to this reviewers suggestion, the authors assert it is better to not change the title because the paper is already published in HESSD. This is not an appropriate reason for not changing the title.

Thank you for using the reviewers' comments to make your manuscript stronger. There are still some issues with your uncertainty section that I have addressed via some edits and comments marked electronically on the Pdf that I am attaching. Please keep in mind that the purpose of your uncertainty discussion should be not to evaluate uncertainty, but rather to comment on the possible consequences of uncertainty in the climate predictions on your results, and in turn, on your conclusions. It is OK for this discussion to be mostly qualitative and speculative. Please revise this section and submit the next version. Thank you!

Thank you for continuing to improve your manuscript. I am approving it for publication. There are a number of additional improvements that can still occur through editing of the English, but the HESS editorial staff will handle that in the next stage.

Best Wishes,
Graham Fogg