Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript presents a detailed study of applying combined ML and DL methods for streamflow reconstruction in the Sava River Basin. The integration of scPDSI proxies and bias correction techniques (post-processing) provides a robust framework for addressing data limitations and enhancing predictive accuracy. Given the increasing challenges of water resource management under changing climatic conditions, the findings are timely and relevant. However, there are areas where clarity, depth, and rigor can be improved to strengthen the overall impact of the study. I recommend this for minor revision. Please find my comments below;

1. The introduction provides a solid foundation and is well-written. However, a clearer overview of how the proposed approach uniquely addresses these gaps (in bullet form) would enhance the main findings.

2. I liked how the authors briefly discussed the algorithms used without providing unnecessary details of each algorithm. 

3. The selection of scPDSI grid points within a 450 km radius could be further justified by elaborating on the spatial correlation analysis or domain knowledge that informed this choice.

4. The post-prediction bias correction using the RQUANT method is a novel addition but lacks a detailed explanation of its implementation. Including a mathematical formulation or flowchart would provide clarity.

5. The comparative analysis of ML and DL models highlights the superior performance of the 6-layer DL model. A discussion on why this architecture outperforms simpler models would add value to the interpretation.

6. The discussion on paleo-drought intervals is really interesting but could be enhanced by connecting these findings to regional water management strategies or historical climate impacts.

7. The limitations section is underdeveloped. For example, the potential biases introduced by using scPDSI as a proxy or the limitations of training data size deserve more attention.

Other Comments:

Citations are missing, and some text is overlapping. I faced some difficulty in following the paper smoothly.

Page 4, Line 152: Clarify what "climatic variability" specifically refers to in the context of streamflow dynamics.

Page 5, Line 163: "dot kernel" in SVM should be replaced with "linear kernel" for precision.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The aim of the paper was to reconstruct historical river discharges and determine the hydrological dynamics and variability of climate with the use of the tree-ring based paleo data and selected statistical tools. The Sava River basin in South-Eastern Europe was taken as a case study. The research was carried out based on the daily discharges recorded in the multi-annual period 1926-2022. In my opinion, the study is valuable as it sheds a new light on the historical streamflow with a focus on low-water periods in relation to climate variability conditions. The findings of this study may be useful for example in prediction of river low flows under the conditions of contemporary climate change. I recommend publishing it in the journal. However, I would suggest some improvements prior to the final acceptance of the manuscript for publication. My detailed comments are as follows:

1. The citations of papers are unreadable because they are replaced by the characters "?" throughout the manuscript. Please correct. Moreover, please add numbering to papers listed in references.

2. P. 4, l. 127-130: “The hydrological systems in the Sava basin exhibit varied characteristics, shifting from alpine nival-pluvial systems upstream to Peripannonian and Pannonian pluvial-nival systems downstream. These changes reflect the complex interplay of climatic, topographic, and hydrological factors influencing the Sava River and its tributaries.” Please extend this by adding more details on the seasonal variability of runoff of the Sava River and the occurrence of low flows in the analyzed gauge Sremska Mitrovica.

3. P. 4, l. 141-142: “The daily discharges were aggregated to monthly, and the April-May-June-July-August-September (AMJJAS) season was selected.” Please justify the selection of the April-May–June–July–August-September stream flow season for your analyses.

4. In hydrology and water management there are different criteria of distinguishing the threshold value of low flows. What was the criterion for distinguishing the low-flow periods in the multi-annual period 2000-2022? Please specify.

5. The manuscript requires some editorial and linguistic improvements.

Generally, it is recommended to accept the paper for publication after major revisions, made in accordance with the aforementioned comments.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Comments are included in the attached file

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

In my opinion, the Authors have made satisfactory corrections to the manuscript, in accordance with the reviewer's suggestions. The Authors' responses to the reviewer's comments are also satisfactory. It is therefore recommended that the manuscript be accepted for publication in its present form.

Author Response

Comments 1:

In my opinion, the Authors have made satisfactory corrections to the manuscript, in accordance with the reviewer's suggestions. The Authors' responses to the reviewer's comments are also satisfactory. It is therefore recommended that the manuscript be accepted for publication in its present form.

Response 1:

We sincerely appreciate your positive feedback and your recommendation for acceptance. We are grateful for your time and effort in reviewing our manuscript and for your thoughtful evaluation.

Reviewer 3 Report

Comments and Suggestions for Authors

Once the problems with references ere fixed , the paper can be apprised. It is a fine piece of work that deserves to be published in the Water journal. Congratulations to the authors.

Only a minor comment. The river is mentioned as Sav or Sava. I think this must be unified.

 

 

Author Response

Comments 1:

Once the problems with references ere fixed , the paper can be apprised. It is a fine piece of work that deserves to be published in the Water journal. Congratulations to the authors.

Response 1:

Thank you for your positive assessment of our work and for recognizing its contribution. We appreciate your time and effort in reviewing our manuscript.

Comments 2:

Only a minor comment. The river is mentioned as Sav or Sava. I think this must be unified.

Response 2:

Thank you for pointing out the inconsistency in the naming of the river. We have carefully reviewed the manuscript and ensured that "Sava" is used consistently throughout.