Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This manuscript presents an application of the InVEST Annual Water Yield (AWY) model to assess long-term water yield dynamics in the Urucuia River Basin, Brazil, under changing land use and climate conditions. The study is timely and relevant, especially given the mounting pressures on water resources. However, the paper has several structural, methodological, and interpretive issues that must be addressed before it can be considered for publication.

#1 The literature review omits several relevant studies on forest disturbance and hydrological response. The following papers should be considered to strengthen the context and grounding of the study:

Li, Q., Wei, X., Zhang, M., Liu, W., Giles-Hansen, K., & Wang, Y. (2018). The cumulative effects of forest disturbance and climate variability on streamflow components in a large forest-dominated watershed. Journal of Hydrology, 557, 448-459.

Wei, X., & Zhang, M. (2010). Quantifying streamflow change caused by forest disturbance at a large spatial scale: A single watershed study. Water resources research, 46(12).

Aryal, Y., & Zhu, J. (2020). Effect of watershed disturbance on seasonal hydrological drought: An improved double mass curve (IDMC) technique. Journal of Hydrology, 585, 124746.

#2 Abstract: “The model struggled to accurately estimate the basin’s flow, but results showed lower water yield in drier scenarios (higher ET, lower precipitation).”

If the model struggles to simulate observed flow, how can the results under different scenarios be considered reliable? The authors should clarify the basis for confidence in conclusions derived from a poorly performing model.

#3 The AWY model's performance is unsatisfactory (NSE = -0.14), yet the study proceeds with scenario analysis without adequate justification.

#4 The conclusion is weak. The following sentence should be revised: “While the model results offered valuable insights into how water yield may respond to land use changes, its limitations highlight the need for further refinement in the Urucuia River Basin.” Given the limitations, are the general conclusions even valid?

#5 The omission of explicit irrigation abstraction and use undermines the core conclusions about agricultural impacts on streamflow. This is especially problematic given the known expansion of center pivot irrigation in the basin. At a minimum, the authors should quantify potential irrigation water demand and comment on the implications of its exclusion.

#6 The claim that LULC change had minimal impact on water yield is potentially misleading. The limited response may reflect model insensitivity or parameter averaging rather than a true hydrological neutrality of land conversion. The authors must be more cautious in interpreting these results. The scenario combinations are simplistic and arbitrary (e.g., mixing max precipitation with mean ETO and 2020 LULC), and there is no exploration of interactions or uncertainty. The approach lacks rigor and should be either redesigned or acknowledged as heuristic.

 

Author Response

Manuscript Title: Modelling Annual Water Yield (InVEST) for the Urucuia River Basin, Brazil

Point-to-point responses to Referees

Response to Editor and Reviewers

We thank the Editor and Reviewers for their thorough and constructive comments. We carefully considered each point and have revised the manuscript accordingly. Below are our detailed responses.

Reviewer #1

Comment 1:

The literature review omits several relevant studies on forest disturbance and hydrological response.

Response:
We thank the reviewer for this suggestion. We have added the following key references to the introduction to strengthen the context:

• Li et al. (2018), Wei & Zhang (2010), Aryal & Zhu (2020)
  These citations support the link between forest disturbance and hydrological responses in large watersheds.

Further references were added into the Introduction section (highlighted in gray in Sections 2 (Materials and Methods) and 3 (Results and Discussion). All added references are listed and highlighted in gray in the Reference section.

Comment 2:

The model struggled to estimate flow. How can results under different scenarios be considered reliable?

Response:
We revised the abstract, discussion, and conclusion sections to clarify that while model performance was poor in reproducing observed flow (NSE = -0.14), scenario results are interpreted qualitatively. The model’s sensitivity to climate variables supports its use for heuristic and comparative analyses, as discussed in Redhead et al. (2016).

More specifically, we added the following paragraph in the Abstract:

Although the model exhibited low performance in simulating observed streamflow (NSE = -0.14), scenario analyses under reduced precipitation and increased evapotranspiration (ET) revealed consistent water yield responses to climatic variability, supporting the model’s heuristic value for assessing the relative impacts of land use and climate change. The effects of deforestation on estimated water yield were limited, as land use changes resulted in only moderate shifts in basin-wide ET. This was primarily due to the offsetting effects of land conversion: while the replacement of savannas with pasture reduced ET, the expansion of agricultural areas increased it, leading to a net balancing effect.

Comment 3:

The AWY model's performance is unsatisfactory, yet scenario analysis proceeds without justification.

Response:
We now justify this approach explicitly in the abstract, discussion, and conclusion sections. We emphasize the model’s value for relative comparison rather than precise prediction, and we provide supporting citations. Please refer to these sections, particularly the text highlighted in gray.

Comment 4:

The conclusion is weak. Revise the sentence on model limitations and general conclusions.

Response:
We have added a dedicated Conclusion section (Section 4) that summarizes key findings, revisited our research questions, acknowledges limitations, and suggests future refinements.

Comment 5:

The omission of irrigation abstraction undermines the conclusions.

Response:
We agree. Our model did not explicitly account for irrigation abstraction, despite the expansion of center pivot systems in the study basin. Irrigation is indeed a critical factor that should be properly addressed in studies of this region. However, related accurate data is considered sensitive information and is often difficult to access and verify. The omission of this factor likely contributes to the underestimation of streamflow reductions in the observed data. This limitation should be addressed in future refinements of the model.

Comment 6:

The claim that LULC had minimal impact may reflect model insensitivity.

Response:
We revised this interpretation in the Abstract, Discussion, and Conclusion sections to caution readers that the model's parameterization may mask real hydrological effects. We clearly state that results should be considered as heuristic at this stage. Future research, however, should address it.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Please find attached my comments regarding the manuscript.

Comments for author File: Comments.pdf

Author Response

Manuscript Title: Modelling Annual Water Yield (InVEST) for the Urucuia River Basin, Brazil

Point-to-point responses to Referees

31 July 2025

Response to Editor and Reviewers

We thank the Editor and Reviewers for their thorough and constructive comments. We carefully considered each point and have revised the manuscript accordingly. Below are our detailed responses.

Reviewer #2

Comment 1:

Discuss where the model has been applied globally and compare it to other models.

Response:
We added a paragraph in the introduction reviewing global AWY applications (China, Ethiopia, Europe). We explain that AWY is simpler than full-process hydrological models but useful for large-scale land-use assessments.

Comment 2:

Highlight AWY advantages vs. other models.

Response:
Included in the introduction: the AWY model's lower data demand and ease of integration with land use datasets make it appropriate for scenario testing at basin scale.

Comment 3:

Show more detailed outputs of water yield over time.

Response:
We added in results and discussion section and a placeholder for Figure 2, comparing observed and simulated streamflows over time. Water yield estimates and trends are described more thoroughly.

Comment 4:

Lack of detailed comparative analysis between observed and simulated flows.

Response:
We added metrics and narrative analysis of R², PBIAS, and NSE, and provided a comparison figure to show the performance gap explicitly.

Comment 5:

No quantitative sensitivity analysis.

Response:
We added a paragraph summarizing sensitivity analysis results and referenced Redhead et al. (2016) for validation.

Comment 6:

Fix spelling errors (e.g., “precipitao”, “root depht”).

Response:
All identified spelling issues have been corrected. A full language review was also performed.

Comment 7:

Add a conclusion section.

Response:
We have fully revised the Conclusion section, including key results, revisiting research questions, limitations, and research implications.

 

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript proposes the study of the water balance in a river basin using the InVEST AWY, and verifies that the change in land use causes a variation in the evapotranspiometric demand of crops (due to the different Kc). However, there is compensation for the changes in coverage, due to the decrease in ETc for some crops and an increase for others.
In the end, the calibration and validation of the model leaves room for interpretations of unmeasured uses, since the measured flows differ from those estimated to a certain degree.
In this sense, we suggest some checks/corrections throughout the manuscript:
- the authors do not make clear the methodology for filling gaps in the recitation data, requiring better description or review;
- they also do not indicate the MAPBIOMAS collection used for the LULC;
- there was a lack of better clarification of the numerical flow values ​​obtained by the calibration and validation processes in order to demonstrate at what point the model begins to present discrepancies;
- must present the results of the Mann-Kendall Test and the slope obtained;
- must include a CONCLUSIONS item highlighting the responses to the proposed objectives.

Author Response

Manuscript Title: Modelling Annual Water Yield (InVEST) for the Urucuia River Basin, Brazil

Point-to-point responses to Referees

Response to Editor and Reviewers

We thank the Editor and Reviewers for their thorough and constructive comments. We carefully considered each point and have revised the manuscript accordingly. Below are our detailed responses.

Reviewer #3

Comment 1:

Clarify gap-filling for precipitation data.

Response:
We have added a paragraph in Section 2.2 (highlighted in gray) explaining how we have filled the precipitation data gaps.

Comment 2:

Specify the MAPBIOMAS collection used.

Response:
Clarified in the methods: we used MAPBIOMAS Collection 7 (2022).

Comment 3:

Clarify numerical flow calibration/validation results.

Response:
Expanded the results section to show performance metrics and describe the flow simulation’s divergence from observations. We added now a comparison between estimated and observed streamflow data from 1991 to 2020, using a linear regression model in Section 3.1 (Model performance assessment).

Comment 4:

Include Mann-Kendall test results and slope.

Response:
We referenced these results in Sections 2.6 and 3.1 and discuss them briefly in the results. Full output tables/plots can be added as supplementary material if needed.

Comment 5:

Add a conclusion section.

Response:
As above, a dedicated conclusion has now been included. Thank you for this comment.

 

 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors have addressed all my comments. I now recommend it for publication.

Author Response

We really appreciate your help and support throughout this reviewing process. 

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have made significant improvement following previous comments, and i appreciate their efforts. However, i noticed a few minor issues that should be addressed before accepting the manuscript in its current form.

1. In figure 3, please clarify the abbreviations of pp and eto in the caption for better understanding.

2. In figure 4, the label on the y-axis is still in Portuguese, kindly fix it.

I believe addressing those minor issues will enhance the clarity and overall quality of the manuscript.

Author Response

Comments 1: The authors have made significant improvement following previous comments, and i appreciate their efforts. However, i noticed a few minor issues that should be addressed before accepting the manuscript in its current form. I believe addressing those minor issues will enhance the clarity and overall quality of the manuscript.

Response: Thank you so much for all your help and support. We really appreciate your help and support throughout this reviewing process. 

Comments 2:
1. In figure 3, please clarify the abbreviations of pp and eto in the caption for better understanding.

Response: We corrected it accordingly.

Comments 3:
2. In figure 4, the label on the y-axis is still in Portuguese, kindly fix it.

Response: We corrected it accordingly.