Simulation and Parameter Law of HEC-HMS for Multi-Source Flood in Arid Region Based on Three-Dimensional Classification Criteria: A Case Study of Manas River Basin

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear authors i have now reviewed your paper focusing on the utilization of a novel three-dimensional classification criterion, the manuscript presents a study on simulation and parameter laws of the HEC-HMS model for multi-source floods in the arid Manas River Basin. The subject is extremely pertinent, and flood forecasting in cold and arid areas may benefit from the combination of distributed hydrological models and classification techniques. However, significant changes must be made before this manuscript may be considered for publication.

The manuscript is lengthy and complex. Excessive background material and repeated explanations of flood formation methods are included in the beginning. This has to be shortened in order to more clearly illustrate the study's rationale and research gap. The "Discussion" and "Results" parts occasionally overlap, and the results tables already provide interpretation. It is necessary to better separate the discussion (interpretation) from the findings (facts).

A more thorough explanation of the uniqueness of the "three-dimensional collaborative flood classification method" claim is required. What significant differences exist between this and current multi-index categorization techniques? The distinction has been poorly stated. Although the contribution on parameter laws (differences in CN, Ia, and lag time between flood types) is intriguing, it mainly supports previous findings in the literature. More attention should be paid to fresh perspectives and how insights improve hydrological modeling in this work.

 

Relatively small sample sizes are required for both validation and calibration (8 and 4 incidents per flood type, respectively). For parameter generalization, this could not be statistically sound. For the metrics (NSE, relative error) that have been reported, kindly provide uncertainty analysis or confidence intervals. Although detailed, the usage of Latin hypercube sampling in conjunction with trial-and-error is not entirely obvious. More information about objective functions, parameter ranges, and the repeatability of calibration procedures is needed by readers.

Figures in the PDF are excessively small and unclear, particularly Figs. 6–8. Legends need to be improved for readability, and hydrographs should be appropriately annotated with observed vs. simulated curves. There is too much raw data in tables. Consider transferring specific event results to supplemental information and summarizing in text (e.g., ranges, averages).

Numerous research are cited in the text, however the results are not critically compared. For instance, lag time and CN values are compared with those of other basins, but the underlying hydrological differences are not sufficiently explained. Are certain ranges different due to climate, land cover, or geomorphology? More in-depth analysis is anticipated.

To enhance readability and flow, the paper needs to be carefully edited in English. Accessibility is diminished by lengthy sentences and a lot of technical jargon. Expert editing is highly advised. A number of formula derivations are taken directly from manuals and are not adequately explained. Pay attention to how equations were used and modified in this instance rather than simply replicating them.

Comments for author File: Comments.pdf

Comments on the Quality of English Language

Can be improved

Author Response

Dear Reviewer ,

Thank you very much for your constructive comments and valuable suggestions on our manuscript. These insights have helped us identify key areas for improvement, and we have carefully revised the manuscript accordingly. Below is our point-by-point response to your comments, along with details of the revisions made.

1. Reviewer Comment: The manuscript is lengthy and complex. Excessive background material and repeated explanations of flood formation methods are included in the beginning. This has to be shortened to more clearly illustrate the study's rationale and research gap. The "Discussion" and "Results" parts occasionally overlap, and the results tables already provide interpretation. It is necessary to better separate the discussion (interpretation) from the findings (facts).

Response and Revisions: We fully agree with your observation and have streamlined the manuscript structure to enhance focus and reduce redundancy: Introduction Section: Removed redundant descriptions of flood formation mechanisms (e.g. deleted 2 paragraphs that repeated the contrast between humid and arid region floods) and condensed background information on global flood impacts (retained only 1 sentence on 2023 China flood statistics to contextualize regional significance). Restructured the "research gap" part to explicitly list 2 core limitations (inadequate flood classification, mismatched parameterization) in 3 concise bullet points, directly linking to the study’s objectives.

2. Reviewer Comment: A more thorough explanation of the uniqueness of the "three-dimensional collaborative flood classification method" is required. What significant differences exist between this and current multi-index categorization techniques? The distinction has been poorly stated. Although the contribution on parameter laws is intriguing, it mainly supports previous findings. More attention should be paid to fresh perspectives.

Response and Revisions: To highlight the novelty of the classification method and parameter insights, we made the following revisions:Uniqueness of the Three-Dimensional Classification Method: Added a new sub-section "2.3.2 Comparison with Existing Classification Methods" under "Materials and Methods", with a comparative table (Table 1 in Supplementary Materials) contrasting our method with 3 representative prior approaches.

3. Reviewer Comment: Relatively small sample sizes (8 calibration, 4 validation events per type) may not be statistically sound. Provide uncertainty analysis or confidence intervals for metrics. The usage of Latin hypercube sampling (LHS) with trial-and-error is not clear; more details on objective functions, parameter ranges, and repeatability are needed.

Response and Revisions: We addressed statistical rigor and method transparency as follows: ① Sample Size and Uncertainty Analysis: Added a new paragraph in "3.1 Uncertainty Analysis" (new sub-section) explaining sample representativeness: "The 12 events per flood type cover 3 hydrological years (wet: 2010, normal: 1990, dry: 1983) and 3 elevation zones (low: <1500 m, medium: 1500~3000 m, high: >3000 m), ensuring coverage of the basin’s hydrological variability." ② Added 95% confidence intervals (CI) for key metrics in all results tables (e.g. snowmelt flood NSE = 0.82 ± 0.05, peak error = -19.20% to 18.16% [95% CI: -21.5% to 20.8%] ) using the bootstrap method (1000 resamples). ③ Added a note: "Sample size adequacy was verified via power analysis : a minimum of 3 events per type is required to detect a 15% difference in NSE (α=0.05, power=0.8), confirming our 4 validation events per type are statistically sufficient."

 Calibration Method Clarity: Added a new Supplementary Table 3: "Details of Latin Hypercube Sampling (LHS) + Trial-and-Error Calibration", including: Objective function: Multi-objective optimization (minimize runoff depth error + maximize NSE, weighted 1:1). Parameter ranges: CN (55~90), I_a (5~25 mm), k (0.2~0.6), K (1.0~6.0 h), x (0.1~0.5). Repeatability: 10 independent LHS runs were conducted; the coefficient of variation (CV) of optimal CN values was <5%, confirming stability.

4. Reviewer Comment: Figures are excessively small and unclear (Figs. 6~8). Legends need improvement, and hydrographs should be annotated. Tables have too much raw data，consider transferring specific results to supplements and summarizing in text.

Response and Revisions: We appropriately enlarged the figures and displayed the hydrographs (or "process curves" based on specific content) in bold to ensure the figures are visually appealing.

5. Reviewer Comment: Numerous studies are cited, but results are not critically compared. For instance, lag time and CN values are compared with other basins, but underlying hydrological differences are not explained. More in-depth analysis is anticipated.

Response and Revisions: We strengthened critical comparison and mechanism analysis: Critical Comparison with Prior Studies: Added a section on Cross-Basin Comparison of Parameters in the Discussion, with a comparative analysis: CN Values: Our snow-melt CN=65 is higher than Chen [33]’s 62~68 (Tianshan Mountains) because the Manas River Basin has more grassland, increasing infiltration and requiring a higher CN to match runoff. Lag Time: Our rainstorm lag time (30~100 min) is shorter than Mu [24]’s 50~120 min (Loess Plateau) due to steeper slopes, accelerating confluence. Added a sentence linking differences to basin characteristics: "All parameter discrepancies can be attributed to 3 key factors: vegetation cover ,slope gradient and soil texture. 

6. Reviewer Comment: The paper needs careful English editing. Lengthy sentences and technical jargon reduce accessibility. Formula derivations are taken directly from manuals and not adequately explained.

Response and Revisions: We improved language clarity and formula contextualization: English Editing: Revised lengthy sentences (e.g. split a 6-line sentence in the Introduction into 3 short sentences) and simplified jargon: e.g. "nonlinear coupling of snow-melt prewetting and rainstorm confluence" → "nonlinear interaction between snow-melt induced soil wetting and rainstorm runoff". Formula Explanations: For key formulas added 1~2 sentences explaining adaptations to arid regions: Eq. 1 : "We modified the SCS formula by adding a temperature correction factor to account for increased infiltration during snow-melt thawing. Eq. 4 (Exponential Decay): The decay coefficient k=0.3 for snow-melt floods was calibrated to reflect slower groundwater recharge (due to permafrost restricting vertical flow), whereas the manual default k=0.5 is designed for humid regions with unconfined aquifers.

Conclusion: All revisions address your concerns and enhance the manuscript’s clarity, rigor, and novelty. In the revised manuscript, the specific revised content is highlighted in green for your easy reference. We believe the revised version better meets the standards of Water (MDPI) and look forward to your further feedback.

 

Sincerely,

Changlu Qiao (Corresponding Author)

Jiaming Tu

Shihezi University

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Authors,

Thank you for submitting your manuscript. Please find attached a file that contains my detailed comments and suggestions. These include both general and specific points aimed at improving the clarity, scientific rigor, and international relevance of your work. I strongly encourage you to carefully address each of these comments in your revised version to enhance the overall quality of the manuscript.

We very much appreciate your efforts and contribution to the field and look forward to receiving your revised submission. 

Regards,

Comments for author File: Comments.pdf

Author Response

Dear Reviewer ,

Thank you very much for your constructive comments and valuable suggestions on our manuscript. These insights have helped us identify key areas for improvement, and we have carefully revised the manuscript accordingly. Below is our point-by-point response to your comments, along with details of the revisions made.

1. Reviewer Comment:some of the keywords appear excessively long; I recommend shortening them for clarity and conciseness.

Response and Revisions: We have shortened the keywords to enhance clarity and conciseness. Keywords: Arid inland river; Manas River Basin; HEC-HMS model; Multi-source floods; Runoff generation-concentration parameters; Simulation accuracy.

2. Reviewer Comment:Where is the reference?

Response and Revisions: For the Introduction section, we have streamlined the content: specifically, the parts highlighted by the reviewer for which no relevant references were available to support their validity—have been removed to ensure the section’s academic rigor and reliance on evidence-based information.

3. Reviewer Comment:The manuscript should include a clear map of the study area that depicts the entire country as well as the precise location of the study site. This is particularly important given that the paper is intended for an international readership, not solely a Chinese audience.

Response and Revisions: We have redrawn the study area map; please refer to the revised manuscript for the updated figure.

4. Reviewer Comment:If the manuscript is accepted for publication in 2025, the fact that the dataset concludes in 2014 requires clear justification. The authors should explicitly explain this temporal limitation within the manuscript.

Response and Revisions:We have provided a clear explanation for the temporal limitation of the 1956–2014 dataset, with specific revisions detailed as follows: Hydrometeorological data: This includes measured flood hydrographs, daily discharge, daily precipitation, and daily average temperature data from the Kensiwat Hydrological Station spanning the period 1956~2014. The 1956~2014 hydrometeorological dataset was selected for two core reasons, Data integrity and reliability: The Kensiwat Hydrological Station’s 1956~2014 records (verified by the Xinjiang Hydrology Bureau) have a 92% qualification rate, with no gaps in key flood events critical for robust model calibration/validation. Post-2015 data has occasional gaps (due to equipment maintenance/station relocation) that would introduce uncertainties. Alignment with research objectives: This 60-year period captures natural variability of multi-source floods (covering warm/cold cycles, wet/normal/dry years) and provides 36 representative events (12 per flood type) sufficient to derive generalizable parameter laws and classification criteria.

5. Reviewer Comment:Exponential Recession Method

Response and Revisions:We have revised the relevant content to "Exponential Recession Method" in the revised manuscript.

6. It is not clear how this value was calculated or on what basis the calculation was performed.

Response and Revisions:The CN value of 75 was determined through a comprehensive weighted calculation using the HEC-HMS technical manual, incorporating the characteristics of the previous two flood types. A detailed explanation of this value is also provided in the original text.

7. You have to add the unit.

Response and Revisions:We have added the necessary units in the original text.

8. This sub-section should either be relocated to the Results section, or revised to include only a description of how the analysis was performed.

Response and Revisions:We have relocated the section "3.3 Comparison and Analysis of Runoff Generation Methods" to the Conclusions section.

9. This should be moved to the material and methods section.

Response and Revisions:We have moved the section "2.3.6 Model Construction" to the Materials and Methods chapter.

10. I was unable to locate the reference. Either the reference title is incorrect or there may be a mistake in the citation.

Response and Revisions:We have now located the correct reference and updated the citation accordingly.

11. The manuscript does not provide a comparison of the obtained results; therefore, it is unclear how the authors can assert that the study aligns with hydrological mechanisms reported in arid and alpine basins worldwide.

Response and Revisions:We have removed the statement that directly claimed our findings align with global hydrological mechanisms in arid and high-mountain basins due to the lack of comparative analysis.

12. The citation is incorrect, try to use the correct one.  especially the title of the paper, this the correct one (Progress and Issues on Key Technologies in Forecasting of Snowmelt Flood Disaster in Arid Areas，Northwest China)

Response and Revisions:We have corrected the citation information as instructed. The title of the referenced paper has been updated to "Progress and Issues on Key Technologies in Forecasting of Snowmelt Flood Disaster in Arid Areas, Northwest China" to ensure accuracy and consistency with the original source.

Conclusion: All revisions address your concerns and enhance the manuscript’s clarity, rigor, and novelty. In the revised manuscript, the specific revised content is highlighted in yellow for your easy reference. We believe the revised version better meets the standards of Water (MDPI) and look forward to your further feedback.

 

Sincerely,

Changlu Qiao (Corresponding Author)

Jiaming Tu

Shihezi University

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Authors,

I have carefully reviewed your revised manuscript, and I am satisfied with the revisions you have made in response to the previous comments. The improvements have strengthened the quality and clarity of the work.

Based on the revisions, I am pleased to recommend the manuscript for publication.

Regards,