Investigating Basin-Scale Water Dynamics During a Flood in the Upper Tenryu River Basin
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe authors of the manuscript entitled Investigating the Basin–Scale Water Dynamics during a Flood with respect to Rainfall–Runoff and Flood Propagation in the Upper Tenryu River Basin attempt to apply a series of classical methods to identify water dynamics at the level of a hydrographic basin in the Central and Southern Japan Alps. The study is quite well structured but important changes are necessary before it can be accepted.
First of all, a restructuring of the title is necessary, which in this form is much too long. A suggestion that could be taken into account would be: Investigating the Basin–Scale Water Dynamics during a Flood in the Upper Tenryu River Basin. Then the authors should also intervene in the abstract part where the first sentence is also much too long, and in its current form the abstract does not contain the results obtained part.
The introductory part should also be expanded by including many more bibliographical references related to the analyzed topic. At the same time, the authors should clearly specify the scientific object pursued and the elements of novelty brought by the research carried out.
Figures 1, 2, 3 include the specification Out of the target basin in this study at the top. Why did the authors consider it necessary to write it like this and did not leave the background of the numerical model used? The authors also suggest a general map showing the geographical position of the studied area at the level of Japan.
The methodology part needs a flow chart to better understand the steps used. Also, the text from row 228 to row 243 can be transposed into a methodological scheme with the related text.
At the current stage, the results and discussions part only presents the results obtained by applying the chosen methodology. The discussion part is completely missing and should be developed in a separate chapter where the authors should also mention the limitations imposed by the database and the methodology used.
Figure 25 must be replaced with one original figure made by the auhtors not captured from goole.
Also, the comparative analysis of the results obtained with similar results by using the same methodology in other areas was missing.
The authors will also have to mention the results validation system.
The paper needs important modification of the language before be accepted for publication. The authors use sentences that are far too long
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsHello,
The authors used rain radar data, a hydrological model (RRI), and two-dimensional unsteady flow simulations to analyze water storage in the basin and flood wave behavior.
The following comments should be considered through a MAJOR revision.
- The manuscript Numerical results should be presented in the abstract.
- Although radar data have been compared with ground data, systematic error correction has not been performed. Provide additional explanations in this regard.
- The effect of precipitation data error on model results has not been quantitatively investigated.
- Model parameters have been adjusted based on geological classification, but the use of advanced calibration methods (e.g., multi-objective optimization algorithms) could be among the research suggestions.
- Considering uniform distribution of inflow of sub-branches/reaches may not reflect local flow dynamics at junctions well, discuss this further.
- Separation of temporary storage (in the channel) and long-term storage (groundwater) has not been done clearly, which requires additional explanations.
- The effect of initial soil moisture on water storage has not been investigated, provide justification in this regard.
- The kinematic wave equation has been used, which may not be accurate in steep and complex areas, point out these limitations.
- The distinction between "basin storage" and "river storage" should be interpreted in the context.
- No analysis of modeling uncertainty (e.g., in hydrological parameters or data accuracy) is provided in the paper.
- The role of dams in controlling or regulating flow is considered merely as an input to the model, but a more detailed analysis of how dams affect flood dynamics (e.g., peak delay or discharge reduction) is not performed.
- Although the spatial distribution of precipitation and geological characteristics are mentioned, a quantitative analysis of the relationship between geological type and runoff response time or discharge intensity is not performed.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsI am happy to review the manuscript entitled "Investigating the Basin–Scale Water Dynamics during a Flood with respect to Rainfall–Runoff and Flood Propagation in the Upper Tenryu River Basin." This research addresses a highly relevant and important topic in the field of integrated hydrological and hydraulic modeling at the basin scale. The manuscript provides valuable insights, particularly regarding the influence of tributaries on flood wave propagation and the quantitative dynamics of river channel storage under flood conditions.
However, there are several issues that require significant revision before the manuscript can be considered for publication. My comments are detailed below, organized by thematic areas for clarity:
Major Comments
- Insufficient Detail on Methodology Validation
The manuscript lacks a thorough validation of the models used. The authors do not present sufficient statistical measures (e.g., RMSE, NSE, R²) to assess the agreement between observed and simulated data. Additionally, uncertainty analysis is missing, particularly regarding the rainfall data input and model parameters. Without this, it is difficult to assess the reliability of the model outcomes. A discussion on the model limitations, especially considering the complex river morphology, should also be added in the discussion section. - Limited Spatial and Temporal Data
While the study utilizes a rich dataset, the spatial and temporal resolution of radar rainfall and ground observations are not clearly stated. A table summarizing the resolution and coverage of these datasets would significantly enhance clarity to better evaluate the accuracy and limitations of the simulation. - Overestimation of Tributary Inflows (KP170–KP190)
There is a noticeable overestimation of simulated water levels compared to observed values in the KP170–KP190 segment (Figures 17–18). The authors are encouraged to reassess tributary inflow estimations and consider potential sources of error such as rainfall intensity estimation, infiltration, or lateral inflow assumptions. - Evapotranspiration (ET) Assumption
The model applies a fixed ET rate of 4 mm/day throughout the flood event. This simplification is not justified with observational data or literature references. Given that ET dynamics can vary significantly during flood events, the authors should either validate this assumption or adopt a more realistic time-variable approach. - Results and Discussion Must Be Separated
The manuscript currently combines the results and discussion sections, which dilutes the analytical depth. These should be separated to clearly distinguish between the presentation of results and their interpretation. The discussion should explore the implications of findings, contrast them with existing literature, and address the uncertainties, assumptions, and broader relevance of the outcomes.
Figures
- Excessive Number of Figures
The manuscript currently includes 26 figures, many of which could be consolidated. Consider using multi-panel figures (e.g., Figures 5a, 5b, and 5c) or converting some figures to tables or summary charts where appropriate. This will reduce redundancy and improve the readability of the paper. - Map Figures: Incomplete Components and Inconsistencies
All map-based figures must include standard cartographic elements: legend, north arrow, scale bar, title, and coordinate grid. Furthermore, ensure uniformity in font size, typeface, and style across all figures for a consistent and professional appearance. - Figures Difficult to Interpret
Figures 3, 14, and 25 are overly cluttered and lack clear legends, making them hard to interpret. Please revise these for better clarity and visual accessibility.
Technical and Stylistic Issues
- Geological and Hydrological Variability
The manuscript mentions geological variability as influencing runoff behavior, but the discussion remains superficial. A more detailed explanation is needed to show how geological heterogeneity affects storage and runoff processes, especially during extreme rainfall events. - Language and Grammar (Pages 25–26)
There are a few unclear phrasings:
- “Visualized and quantitatively assessed” Consider rephrasing as “The relationship between accumulated net precipitation and basin storage was visualized and quantitatively analyzed.”
- “which incorporated all tributary inflows estimated using the RRI model, successfully reproduced this peak timing inversion” → This can be clarified as: “The two-dimensional flow model, incorporating all tributary inflows estimated via the RRI model, successfully reproduced the inversion in peak timing.”
- Sentence Structure
Several sentences are overly long and complex, hampering readability. For example, the sentence beginning with “A two-dimensional unsteady flow simulation...” should be split or restructured for clarity. - Typographical and Formatting Issues
There is inconsistent hyphenation, e.g., “runoff–discharge” vs. “runoff-discharge.” Consistency should be maintained throughout. Additionally, abbreviations like “RRI model” should be clearly defined at their first occurrence. - Subsection Titles Are Repetitive
Subsections such as 4.1 and 4.2 have similar or repetitive titles, which can be confusing. More descriptive and specific headings would help guide the reader more effectively through the content.
Comments on the Quality of English Language
The English could be improved to more clearly express the research.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThe authors has made some modification related to the manuscript but in the figures they didn't extract the teh area with out the the target study area. Why?
Author Response
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Author Response File: Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsHello,
The revisions have been made to the text, and the article is now acceptable for publication. I look forward to seeing it published!
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for Authorsi am happy with the current changes. The authors have revised the mnuscript significantly.
Author Response
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Author Response File: Author Response.pdf
