Interactive comment on “ Storage water value as a signature of the climatological balance between resource and uses ” by B

The paper describes an interesting approach to explore the outputs of reservoir optimisation with dynamic programming to better understand system’s behaviour, time variability and impacts of changes in climatic forcing on the storage water value (SWV). A case-study in France is used in the study. I found the paper interesting and within the scope of HESS. The topic is very broad and I think the authors found a careful way to present the content in a concise way. In general, it is well written although I agree with the previous reviewers that some English language review is necessary. Mainly the lack of punctuation in long sentences makes reading sometimes difficult (eg., page 8995 lines 10-15). A proper use of comma, for instance, would be enough to solve this problem and favour fluid reading.

Additionally, I have the following main issues that I would like to be addressed by the C4641 authors: -I like concise papers but here sometimes I found it too concise! In many parts the reader is sent to a reference without much explanation: for instance, what is actually in these studies mentioned by the authors: page 9003, lines 13-14, Paiva et al., 2010;Page 9003, line 25, Ward et al., 1996;Page 9004, line 21, Hingray et al., 2007;page 9006, lines 2-3, Paiva et al., 2010 again? A sentence or two about what is to be found in the cited reference would be much appreciated.
-Also related to this issue, I agree with reviewer 2 that some terminology needs to be explained. For instance, page 8995 line 4, I do not see clear what "inflows from past hydrological regimes" means. Should not a catchment have only one hydrologic regime (under stationarity at least)? Later on line 7, what is a "rule curve"? -I agree with reviewer 2 that the introduction needs a major revision, together with the conclusions section. I think the introduction is too concise and fails in telling the reader what the major achievements in the field are. More information on the literature is needed in the pa-per: what other recent studies applied deterministic dynamic programming? What studies show operational applications of dynamic programming for reservoir control? What are their main achievements/conclusions? What has been done of innovative in dynamic programming and what are the current challenges in the field (isn't there something more recent than the review of Yakowitz, 1982?) How the study presented in the paper searches to fill the existing gaps and/or answer remaining challenges? This would highlight the contribution of the authors to the topic, which, although the study is an interesting one, is not clear in the paper. In my opinion, the topic of un-certainties (nor pertaining only to future inflows in real time operation of reservoirs, but also to observed flows and expected climate changes), which is very quickly treated in the conclusion, should be presented already in the introduction. This would help in jus-tifying, for instance, the choice of the authors for a determinist dynamic programming, C4642 instead of a stochastic approach.
In the conclusions, I think the authors could discuss more about how their modelling approach could be used in real-time forecasting, mainly considering the use of probabilistic or ensemble-based predictions of future inflows: can it be directly used? How? What adaptations would be needed? Also, page 9013, lines 27-29, for instance, the sentence "The SWV is known to increase in this case when compared to the SWV obtained with perfect foresight, as a result of inflow variability and forecastability." is not clear to me: it is known by whom? What studies/results are you referring to? Also, Page 9014, line 3: when you talk about "changes in the variability of future inflows", I was wondering if these would not already have been captured (under the hypotheses of stationarity) in the control period. What changes otherwise are you talking about? Finally, Page 9014, line 5-7, last sentence: "Analysing these signature changes would probably improve our understanding of modifications of system performance classically reported on the basis of a variety of performance criteria in climate change impact analyses.", what reports are you talking about? What performance measures?
-About the data and the use of a hydrological model: Why do you need a model to apply the dynamic programming and discuss on the variability of SWV as you did in the study? Couldn't you have used the long time series of observations (instead of "control simulations")? Besides, are the observed data stationary? If not, couldn't any changes in observed data be used to test the effects of inflow changes on SWV? Since you used a hydrological model, can you add a sentence or two on the quality of the simulations of the model? How good/bad is the model in reproducing discharges? Also, why did you use meteorological reanalyses (Page 9004, line 13-14) and not observed data for the control period, i.e., why not use the same data used for the calibration of the model?
What is the quality of the reanalyses in this catchment?
-Page 9004 "climate scenarios": when using the scenarios of changes in precipitation and temperature together, did you take into account correlations between the variables?

C4643
Minor points: The last sentence of the abstract seems to be missing something (or "with" is to be replaced by "if"?) Page 8997, lines 10 and 14: is t0 and ti+1 the same thing? Shouldn't it be equal in these lines?