Investigating Groundwater–Surface Water Interactions and Transformations in a Typical Dry–Hot Valley Through Environmental Isotopes Analysis

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The study dealt with the use of water isotopic composition to differentiate the origins of surface water, groundwater and the sources of atmospheric moisture causing precipitation over the Yuanmou dry-hot valley in southwest China. The approach of the study is well known and widely applicable worldwide. The results obtained are rich and the interpretations are acceptable. English is good. So I suggest that the paper can be published. However the ms needs minor revisions as follows.

• The legend in Fig.1a and b is too small, it is difficult to read!
• The values of isotopic composition in water presented in Fig. 1c would be better to show the delta-18O instead of delta deuterium, because the precision of d18O is 10 times higher than that of d2H.
• Line 146: It is probably the precision (repeatability) but not accuracy.
• Please indicate your QC programme to ensure your accuracy in the determination of d2H and d18O in water samples collected!
• In your ms you didn’t show a statistical program applied for data processing. I would advise you to apply Student’s t-test to justify whether there are significant or not significant differences between values of d2H and d18O in water samples collected from different seasons.
• Please check grammar for line 484.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Greetings. The paper entitled “Investigating Groundwater-Surface Water Interactions and Transformations in a Typical Dry-Hot Valley Through Environmental Isotopes Analysis” deals with isotope analysis for analyzing the interactions between surface water and groundwater in a Chinese valley. The study is well suited and the English language is ok. I am not an expert on isotopes, so my comments pertain to the hydrogeological perspective. It would be important to highlight the pre-analysis and post-analysis (thus, in the discussion) role of the information about the relationship between surface water and groundwater from a spatial viewpoint, as suggested below.

• Do you have at your availability a (representative) hydrogeological section to understand the characterization of the aquifer in the vertical direction?
• Is there available a piezometric map for the area to appraise major groundwater patterns? (see Fetter, 2001). If yes, you can use it to retrieve mean groundwater flow directions: please add arrows to highlight flow directions. If not, you can connect points to qualitatively see where the is groundwater going, and put arrows as well to identify major flow patterns.
• Then, please compare the surface stream network to the groundwater one (Schiavo, 2025). Are there any similarities? Can you incorporate eventual similarities within the discussion, comparing this point with the results stemming from the isotope analysis?
• Are the pathways of the Jinsha River followed by groundwater? Can you comment the information given by the samples along the streamwise coordinate? If this matches the groundwater one, can you incorporate this point in the discussion?

Suggested references:

Fetter, C. W. (2001). Applied Hydrogeology. Pearson New International Edition, 4^th Edition.  

Schiavo, M. (2025). Quantile-Based Approach for Improving the Identification of Preferential Groundwater Networks. Water, 3374103.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf