The authors have made a significant effort to address the reviewers comments, but some questions still important questions remain. Both reviewers have offered rebuttals to the authors' comments, and while these came in a little too late to be included in the open discussion, they are included below.

I would encourage the authors to address these comments fully in a revised manuscript, as the AE will scrutinize them to determine the paper's suitability. However, a concerted effort to address all of the reviewers' comments in a substantive manner will likely lead to s successful conclusion to this review process .

Reviewer #1 Rebuttal:

I thank the authors for a thoughtful revision of this manuscript, which adequately addresses the majority of my initial concerns. In this additional comment, I offer a few additional reactions to the paper as it currently stands.
1. Reviewer 2 raises an important point about the need to correctly account for the marginal value of water in agriculture, and I am not sure I follow the approach taken by the authors to specify this. It appears that they have based this value on a multiplicative function of yield and water content, but this would seem to me to still be an average value (not a marginal one), since what would be needed is the contribution of an additional unit of water to an additional unit of yield, to isolate the correct parameter.
2. Though it is true that the treaty constraints do limit irrigation expansion (as shown in the new “NA” scenarios of Figure 1), my interpretation of the results differs somewhat from that of the authors (or at least their statements of it are somewhat confusing and contradictory). Specifically, they say that “the value of hydropower and/or hydrological or treaty constraints limit the attractiveness of an irrigation driven pathway in this scenario.” In fact, I don’t think it has anything to do with the value of hydropower, i.e., there is very little real tradeoff between hydropower production and agriculture. This can be seen by the results across high and low value hydropower scenario. The reason for this is fairly simple, regardless of irrigation withdrawals, there is sufficient flow continuing to Egypt such that power production at Merowe (the main dam affected negatively by more water use in irrigation in Sudan) is not affected in a major way, until irrigation expansion beyond the treaty constraints is allowed.
3. While I appreciate the change in title and agree that it better reflects the nature of the paper, some qualitative discussion of the dynamics of other rivers (White Nile and Atbara), and how they could enrich or alter the Blue Nile optimization performed here, is warranted.
4. In response to my comment about effects of increased withdrawals on Egypt and basin benefits, the authors state that: “Past studies (Whittington and Blackmore) have shown that decreases in inflows to Aswan Dam would lower water levelsin the dam and decrease the total amount of water lost to evaporation, thus increasing basin-wide benefits.” My recollection of Whittington & Blackmore is that they said reduced evaporation at Aswan would increase the amount of water that can be used by Nile riparians, but it does not follow that this would increase basin- wide benefits, which depends on the distribution of the changes and whether they occur in high or low-value sectors.
5. It would be more straightforward to report the sensitivity of front-loading demands to discounting by showing what the annual withdrawals are over time in the scenarios used to test for this. Showing the benefits each year is unnecessarily opaque.

Reviewer #2's rebuttal involves two specific requests:

(1) That the authors clearly indicate that 14.5 bcm is an ASSUMPTION they make because they do not include the irrigation schemes in the other river basins in Sudan, and

(2) It would be nice if they mention the alternatives to their deterministic model. For example, could the hydro-eco model be implemented in an on-line mode (receding horizon) with updated flow forecasts? Would properly capture the uncertainty without major changes to the code

Thank you to the authors for making some a concerted effort to revise the manuscript. This paper is clearly much improved with respect to the way that the Nile system itself is represented, or at least the larger assumptions are more clearly stated. When publishing similar work in the future, I think that the authors would be well advised to invest more time up front in better understanding the management side of the system, and then framing the questions and analysis to be undertaken (it almost seems like things were done in the opposite order here). This approach is likely to yield a more straightforward review process and a more robust manuscript.