Evaluating Trade-Offs in Ecosystem Services for Blue–Green–Grey Infrastructure Planning

Round 1

Reviewer 1 Report

This research monetized the environmental benefits under different blue-green-grey infrastructures from an economic perspective through CBA methods.   It will help enrich the use of the CBA method in urban planning area, and also offer a reference of methodology in planning practice.

The methods were traditional, but it is used to help support new research questions. Thus, it is very needed to clarify your research question and hypothesis in your introduction part. The specific research gap should be highlighted better in the introduction part. More relevant research and their methods should be reviewed.

I think the focus should be like how to figure out the most appropriate planning scenario for infrastructure supply through CBA. Research hypothesis is also required.

I see your location map in supplementary document, why not move it to the main manuscript? It will also helpful to include a map of your site for readers to know more about the infrastructure planning.

Needed more concluding points to show how this research addressed their main questions.

The current manuscript seem not well ready for submission, because there are many citations cannot be located. Many citations in the text are unclear, which show 'reference sourse not found' many times. I think the authors need to check the cross-ref links.Please check them throughly and carefully.

I appreciate your results, some of which are quite interesting. BUT, discussion is insufficient to explain especially the different findings with previous studies.

English  language is OK.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Title

The title is clear and accurately represents the content of the paper. However, it might benefit from a minor adjustment for readability, such as: "Evaluating Trade-offs in Ecosystem Services for Blue-Green-Grey Infrastructure Planning."

Abstract

1.       The abstract seems to be packed with a lot of information, making it a bit overwhelming. Breaking it down into simpler sentences could help.

2.       While the abstract mentions "warm periods," it does not define what constitutes a warm period, leaving room for ambiguity.

3.       The paper seems aimed at academics and practitioners in urban planning, but this isn't explicitly stated. Knowing the intended audience can make the paper's utility clearer.

4.       While terms like NPV, CBA, and blue-green-grey infrastructure might be clear to those in the field, not all readers may be familiar with them. Briefly defining these might make the paper more accessible.

5.       It would be beneficial to include a final statement that captures the broader implications or applications of the research.

Keywords

The keywords are appropriate and cover the major themes of the paper well. However, you might also consider adding "urban planning" or "ecological benefits," given that these are integral aspects of the research.

Introduction

1.       While you have cited a lot of articles, the discussion of these works feels more like a list than a narrative. Consider integrating the literature in a way that tells a coherent story.

2.       Some sentences are quite long and complex. Breaking them down could improve readability.

3.       While you mention that the study will assist "relevant government management and policymakers," it may be useful to expand on this. What other stakeholders might find this research useful?

4.       It might be beneficial to more explicitly state what new contributions your study will make to the existing body of knowledge.

5.       Terms like "urban functional areas" and "ecosystem services" are used but not explicitly defined. Providing short definitions or examples could enhance clarity.

6.       Maintain consistent terminology. For example, if you start by calling them "urban functional areas," stick with that term throughout the paper to avoid confusion.

Material and methods

2.1. Study Area

The mention of "Error! Reference source not found" suggests that there should be tables or figures, but these are not provided. This should be corrected.

2.2. Data Collection

The use of ENVI-met is well explained. However, adding why ENVI-met is an appropriate tool for this research could further strengthen this section.

The scenarios of "adding" and "replacing" are well defined, although more details could clarify the rationale behind choosing these particular scenarios.

2.2.2. Sources of Cost

The use of local construction and maintenance indices adds credibility to the cost calculations.

2.3. Cost-Benefit Analysis (CBA)

The methods chosen for measuring ecological benefits are well outlined. However, it's crucial to justify why you chose the Replacement Cost Method over others.

Some of the terms like Hedonic Price Method, Shadow Price Method, etc., are introduced but not defined. Short explanations would make it easier for the reader to follow.

Remaining section

1. The paper does a good job of setting up the equations and calculations needed to understand the costs and benefits of different types of infrastructure. However, the equations could be better explained to make the paper accessible to a broader audience.
2. The focus on Guangzhou, with its subtropical monsoon climate, is interesting, but it would be helpful to explain why this location was chosen and how these findings might translate to other regions.
3. The paper is quite detailed in how costs and benefits are calculated, which adds to its credibility. But it needs a bit more clarification on why certain variables and equations are chosen over others.
4. While the mathematical equations provide a detailed insight into the calculations, there is little to no textual explanation accompanying them. A layman's explanation could make it easier for readers less familiar with the technical details.
5. All the constants, units, and variables used should be defined and explained clearly. For instance, the electricity charge of 0.086 $/kW·h could be better contextualized.
6. The use of short-term and long-term service life for assessing costs and benefits is good but requires some justification. Why are 25 years and 150 years chosen as short-term and long-term respectively?
7. A 6% discount rate is cited, based on prior research and standards. More explanation should be offered about how this number was arrived at and what the implications are for the overall study.
8. Some sentences are cumbersome and could be rewritten for clarity. For example, the section on the discount rate and net present value could be simplified without sacrificing accuracy.

Results and Discussion

1. There are several instances where you mention "Error! Reference source not found," which suggests issues with the document’s formatting or referencing. This should be corrected before final publication.
2. Citations are abundant, which adds credibility. However, ensure that all the citations are pertinent and contribute to the discussion.
3. While the text suggests that blue infrastructure generally provides the best cooling effects, it's not entirely clear how consistent this is across different kinds of areas (parks, squares, residential districts). More explicit comparative discussion could be useful.
4. The discussion of fitted equations and temperature models is interesting but quite technical. Consider summarizing key insights for a more general audience while retaining the technical details for those interested.
5. Discussion about the practical applications of your results in real-world scenarios would make the paper more appealing to a broader audience.

Conclusion

1.       While you've outlined that different scenarios were more beneficial for different areas, more insight into why this was the case could add depth to your conclusion.

2.       Briefly summarizing the methods employed to monetize environmental benefits can add context.

3.       Good that you've included this, but maybe be more specific. What kind of impact could these shortcomings have on your findings?

4.       Your recommendations are excellent but could be more specific. For example, you could suggest specific types of synergies between blue-green-grey infrastructure worth exploring.

5.       Consider adding a final statement that encapsulates the study's primary findings and implications.

Some sentences are cumbersome and could be rewritten for clarity. 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Dear authors,

The proposal is exciting and promotes the economic advantages of implementing this type of sustainable strategy in urban environments. I recommend to expand the criteria on which they were based to select their variables.

For example:

a) "In this study, two ecological ser,vice benefits of blue-green infrastructure were measured. The air purification benefits are mainly influenced by traffic volumes The seasonal variation in the purification effect was little, while the energy savings depend mainly on air condition usage, i.e., energy consumption for cooling in summer and heating in winter."

According to which authors or regulations in the country of the study site?

b) "In the same way, the highest plant/building height (h) max in the study area is used as the upper limit of the vertical range. We measure the average PM 2.5 concentrations at different height s within the spatial extent" 

Are these PM2.5 concentrations the same at any time of year and time? Why did they only focus on its relationship with the heights of the buildings?

These are just some examples of what could be improved in the Methodology section.

Best regards

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Accept in present form

Accept in present form