Evolution of the Groundwater Flow System since the Last Glacial Maximum in the Aksu River Basin (Northwest China)

Round 1

Reviewer 1 Report

here are five technical comments for minor revisions:

In the introduction part, it will be helpful to refer to more chemistry related materials for this paper, the article blow is suggested to be consulted as a starting point. Status and outlook of oil field chemistry-assisted analysis during the energy transition period. Energy Fuels 2022.

Methodological Clarification:

Comment: On Page 3, the paper mentions the use of various parameters from borehole KT11, including palaeopollen composition, MS, Rb/Sr, and TOC, to reconstruct the sedimentary environments and palaeoclimate. It would be beneficial to provide a more detailed explanation or reference on how these parameters were measured and interpreted.

Suggestion: "Consider elaborating on the methodologies used for obtaining and interpreting the palaeopollen composition, MS, Rb/Sr, and TOC from borehole KT11. This will provide clarity to readers unfamiliar with these techniques."

Clarification on Geological Timeframes:

Comment: On Page 2, the manuscript discusses various geological periods, such as the Last Glacial Maximum and the Pleistocene. For clarity, it might be helpful to provide specific timeframes or dates for these periods.

Suggestion: "Incorporate a table or a brief section that provides specific timeframes or dates for the geological periods mentioned, aiding in the reader's understanding."

Discussion on Groundwater Flow Systems (GFSs):

Comment: The abstract and Page 2 delve into the evolution of Groundwater Flow Systems (GFSs). While the current description is comprehensive, a visual representation or a schematic diagram illustrating the evolution might enhance comprehension.

Suggestion: "Consider adding a schematic diagram or flowchart illustrating the evolution of GFSs in the Aksu River Basin. This will provide a visual aid to readers and complement the textual description."

Clarification on Regional Differences:

Comment: On Page 3, the paper highlights some unsolved problems regarding groundwater studies in the Aksu River Basin compared to other regions. It would be beneficial to provide a comparative table or figure highlighting the key differences and similarities between the regions.

Suggestion: "Incorporate a table or figure that contrasts the key findings and methodologies used in groundwater studies in the Aksu River Basin with those in other regions. This will emphasize the unique challenges and insights gained from the current study."

Enhanced Discussion on Implications:

Comment: The manuscript provides a thorough investigation of the groundwater circulation and its controlling mechanism in the Aksu River Basin. However, the broader implications of these findings, especially in the context of climate change and human activities, could be further emphasized.

Suggestion: "Expand the discussion section to delve deeper into the broader implications of the study's findings. Highlight how the insights gained can inform water resource management, policy-making, and future research in the context of changing climatic conditions and increasing human activities."

English fine

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

The manuscript by Hu Su, Yinger Deng, Weihua Nai, Rui Zhang, Jihan Huang, Pengjie Li, Hongkun Yang, Lin Chen and Ning Wang, entitled “Evolution of the groundwater flow system since the Last Glacial Maximum in the Aksu River Basin (Northwest China)” analyses in detail the hydrogeological conditions, geophysical inversions, particle size characteristics, and logged stratigraphy and chronology of the Aksu River Basin at the northwest margin of the Tarim Basin and combines them with the upstream glacial sedimentary sequences, pedestal terrace features, and other parameters.

First of all, I would like to stress out the overall importance of this study. One of the most pressing problems of the 21st century is providing the population and various sectors of industry and agriculture with high-quality water, and the efficient use of water resources. Yes, people have been working with water for a long time; there is not a single industry, not a single enterprise that is not touched by water. It seemed that we knew everything about water, but the more we study it, the more we discover anomalous, interesting facts that are waiting to be explained.

Since water is a strategic product, it is associated with fundamental scientific problems that need to be solved in the very near future. It is possible that the principle of actualism, which is so widespread in geology, will help solve some problems. Its meaning lies in the fact that the processes, phenomena, forces, laws and factors that we can observe or restore today also acted in the past.

That is why the authors of the manuscript presented a reconstruction of sediments in the Aksu river basin, carried out on the basis of a detailed analysis of multidisciplinary geological data.

The results of the present study showed that in the Aksu river basin there is a complex relationship between the glacial-sedimentary sequence of the Tomura Peak region, climatic evolution, neotectonic movements and sedimentary facies of the foothill basin.

The authors of the manuscript examined in detail the climatic evolution of the Aksu Tarim river basins; it has been established that the climate is currently drying out in the study area. Natural and anthropogenic influences on the groundwater system over the past 2000 years have led to the formation of an active localized GFS.

The research carried out made it possible to obtain new knowledge about the groundwater system of the study area, revealed patterns in the evolution of the Aksu and Tarim river basins, and also better understood the mechanisms of formation of the GFS for the above-mentioned territory.

Noteworthy is the very detailed, simply exhaustive list of references used.

I believe this manuscript deserves to be published in Water after addressing my minor comments.

Minor comments:

Page 5, Line 1: Typos – “2.2Hydrogeological. conditions”

Figure 2, 3, 5, 9 – please enlarge, lettering is too hard to read.

Table 1 – very hard to understand, too much line breaks almost in every cell.

Author Response

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Reviewer 3 Report

- The title of Figure 1 is not clearly understandable, likely due to the excessive use of dashes without spaces in between and parentheses. Furthermore, it is unclear what 'Monsoon-Asia Region' corresponds to and what the orange arrow labeled as 'westerlies' represents in the image. In the description of Figure 2, it should be noted that the mentioned cross-sections are depicted in Figure 1.

- It is not clear from Figure 3 and 5-7 where the groundwater was located.

- In Figure 4, it would be more appropriate to use a different color scale so that, for example, the dark blue color does not correspond to values of 1400, then 850, and then 400. It is also necessary to include the unit for thickness.

- Figure 9e is missing, and Figure 9c is included twice.

-The Methods are concisely described, whereas the Results are extensively elaborated.

-The Conclusion in its length could be more concise and shorter. If I understand correctly, in summary, this paper examines the evolution of the groundwater flow system (GFS) in the Aksu River Basin, located on the northwestern edge of the Tarim Basin, from the Last Glacial Maximum to the present. It reveals that the interplay of tectonic uplift and climate variation has significantly influenced the dynamics of groundwater flow in the region. The evolutionary trajectory of the GFS is categorized into three distinct stages: an era of intense downscaling, followed by a phase of gradual downscaling, and finally a relatively stable period. These transitional phases were intricately linked to shifts in local climate patterns, tectonic activities, and changes in water levels of the Aksu River. This study not only advances our understanding of the evolution of the GFS in this geographic area, but also elucidates its complex connections with climate fluctuations and geological dynamics.

-In conclusion, the term "GFS" could be used more concisely.

Author Response

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Author Response File: Author Response.docx