Restoring Historical Watercourses to Cities: The Cases of Poznań, Milan, and Beijing

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

In the introduction the authors could add a sentence after line 36 that talks about how hard restoration projects can be and what choices they might have to make. This would list the problems with the environment and management. The introduction could also use a clearer explanation of the research hypothesis or the specific questions that the research will answer.

The methods section is clear and explains weel the multi-criteria decision analysis applied for this study. The process is explained in detail, but it's not clear why some criteria were chosen or how important they should be in the analysis. Also, the methods rely heavily on spatial and planning documents, but not much is said about how the data could be wrong or how old maps aren't very helpful. Line 167 only briefly talks about this. After line 170, the authors should say more about how these problems affect the accuracy of their results.

It's good that the study looks at three cities, but it's not clear why Poznań, Milan, and Beijing were chosen. The writers should explain why they chose these cities and how they are similar to or different from other cities. This should happen after line 42 in the introduction or at the start of the methods section.

Results
The results (lines 228–380) are shown in detailed tables and maps that make it easy to see the numbers that show how likely restoration is to happen. Sometimes, though, the presentation doesn't do a good job of explaining things. The results for Milan (lines 275–280) show that full restoration is very unlikely, but the authors don't explain what this means very well. The authors should give more information about why these differences exist and what other cities can learn from them.

The results section (lines 281–380) has a lot of helpful design examples, but they sometimes sound more like project descriptions than scientific analysis. The authors need to do a better job of explaining how these examples fit into the bigger research questions and the GIS-MCDA results.

Discussion: the authors should talk about how case studies can be biased, how criteria weighting can be subjective, and how their results might not be true in other situations. Put this after line 387.
There are also social and technical problems that come up during BGI transitions, but it would be better if these were more directly related to the GIS-MCDA analysis results. It would be best if the authors explain how their results support current theories or practices in urban water management after line 395.

Author Response

Comments 1: In the introduction the authors could add a sentence after line 36 that talks about how hard restoration projects can be and what choices they might have to make. This would list the problems with the environment and management. The introduction could also use a clearer explanation of the research hypothesis or the specific questions that the research will answer.

Response 1: Thank you for pointing this out. We agree with the comment. We have added a few sentences (page 1, Section 1, lines 37-41) about the possibilities and difficulties of introducing restoration projects. As for the second reviewer comment, the research hypothesis has been formulated as one main research question accompanied by two auxiliary questions (page 2, Section 1, lines 59-69).

Comments 2: The methods section is clear and explains well the multi-criteria decision analysis applied for this study. The process is explained in detail, but it's not clear why some criteria were chosen or how important they should be in the analysis. Also, the methods rely heavily on spatial and planning documents, but not much is said about how the data could be wrong or how old maps aren't very helpful. Line 167 only briefly talks about this. After line 170, the authors should say more about how these problems affect the accuracy of their results.

Response 2: Thank you for your comment with which we agree. To explain more clearly the choice of the criteria, we have added a brief description for each criterion (page 6, Section 2.2, lines 237-253). Regarding the issue of accuracy of data, especially that concerning old maps, we have enhanced the explanation of the methods used to solve the problem including georeferencing, as well as the impact on the results (page 5, Section 2.2, lines 218-229). In our opinion, as confirmed during our research, the inaccuracy of data taken from old maps affects the data collection process rather than the results (page 5, section 2.2, lines 229-232).

Comments 3: It's good that the study looks at three cities, but it's not clear why Poznań, Milan, and Beijing were chosen. The writers should explain why they chose these cities and how they are similar to or different from other cities. This should happen after line 42 in the introduction or at the start of the methods section.

Response 3: Thank you for your comment. We selected these cities as the subject of the study due to the diversity of their conditions, as well as data availability. In order to present them more clearly, an introductory paragraph has been added to the section outlining the research materials (page 4, Section 2.1, lines 169-175). After the data collection stage, Beijing was excluded from the scope of analysis due to the limited availability of relevant and comparable spatial data (page 4, Section 2.1, lines 175-177).

Comments 4: The results (lines 228–380) are shown in detailed tables and maps that make it easy to see the numbers that show how likely restoration is to happen. Sometimes, though, the presentation doesn't do a good job of explaining things. The results for Milan (lines 275–280) show that full restoration is very unlikely, but the authors don't explain what this means very well. The authors should give more information about why these differences exist and what other cities can learn from them.
Response 4: We agree with this comment. The description of the results for Milan has been enhanced (pages 10-11, Section 3.1.2, lines 353-369).

Comments 5: The results section (lines 281–380) has a lot of helpful design examples, but they sometimes sound more like project descriptions than scientific analysis. The authors need to do a better job of explaining how these examples fit into the bigger research questions and the GIS-MCDA results.

Response 5: Thank you for the comment. We have added an introductory statement linking the GIS-MCDA results with the presented examples (page 11, Section 3.2., lines 373-375) as well as the classification of each case (page 11, Section 3.2.1., lines 400-402; page 12, Section 3.2.2., lines 416-419).

Comments 6: Discussion: the authors should talk about how case studies can be biased, how criteria weighting can be subjective, and how their results might not be true in other situations. Put this after line 387.
There are also social and technical problems that come up during BGI transitions, but it would be better if these were more directly related to the GIS-MCDA analysis results. It would be best if the authors explain how their results support current theories or practices in urban water management after line 395.

Response 6: Thank you for pointing this out. We agree that it is necessary to add a statement about this issue. We have added a paragraph referring to this, highlighting the limitations resulting from location-specific conditions (pages 14-15, Section 4., lines 487-496). As far as linking technical problems during BGI transitions with GIS-MCDA methods, we described it in the newly added paragraphs (page 15, Section 4., lines 504-513).

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

1.The current research objectives are stated rather broadly . It is suggested to strengthen the formulation of specific research questions or hypotheses, such as: "This study aims to answer what types of historical waterways can be restored under what urban structural conditions?"

2.A brief overview of existing research on urban water body restoration or the application of blue-green infrastructure (BGI) can be added to avoid a "jumping in" approach to the new research.

3. 3. The scoring criteria and source of data for 'site evaluation constraints' are lacking explanation (for example, how the score is derived from '0' to '1' in Table 1?).
4. Have the spatial errors caused by deviations in historical maps been considered? Is there any uncertainty sensitivity analysis? If not, it can be explained in the discussion how it affects the results.

5.The Beijing section resembles a "supplementary statement" more, not integrated into the GIS-MCDA analysis system. It is recommended to clarify its different research methods or strengthen its "comparative significance".

6.The article images are not uniform in size. It is recommended to modify the image sizes to make them more visually appealing.

7.Some section titles are not numbered or do not comply with MDPI standards (for example, continuing to use '3.2.1' after '3.2.1').

Author Response

Comments 1: The current research objectives are stated rather broadly . It is suggested to strengthen the formulation of specific research questions or hypotheses, such as: "This study aims to answer what types of historical waterways can be restored under what urban structural conditions?"

Response 1: Thank you for pointing this out. We agree with the comment. The research hypothesis has been formulated as one main research question accompanied by two auxiliary questions (page 2, Section 1, lines 59-69).

Comments 2: A brief overview of existing research on urban water body restoration or the application of blue-green infrastructure (BGI) can be added to avoid a "jumping in" approach to the new research.

Response 2: Thank you for this comment. We agree that this overview of existing research was missing. We have added a separate chapter 1.1. State of the art to fill in this gap (pages 2-3, Section 1.1, lines 75-106)

Comments 3: The scoring criteria and source of data for 'site evaluation constraints' are lacking explanation (for example, how the score is derived from '0' to '1' in Table 1?).

Response 3: Agree. We have added a sentence of explanation (page 7, Section 2.2, lines 297-299)

Comments 4: Have the spatial errors caused by deviations in historical maps been considered? Is there any uncertainty sensitivity analysis? If not, it can be explained in the discussion how it affects the results.

Response 4: Thank you for pointing this out. Regarding the issue of accuracy of data, especially that concerning spatial deviations in historical maps, we have enhanced the explanation of the methods used to solve the problem including georeferencing, as well as the impact on the results (page 5, Section 2.2, lines 218-229). In our opinion, as confirmed during our research, the inaccuracy of data taken from old maps affects the data collection process rather than the results (page 5, section 2.2, lines 229-232). We also referred to this issue in the discussion (page 15, section 4., lines 514-517).

Comments 5: The Beijing section resembles a "supplementary statement" more, not integrated into the GIS-MCDA analysis system. It is recommended to clarify its different research methods or strengthen its "comparative significance".

Response 5: Thank you for the comment. It was not clearly explained indeed. After the data collection stage, we have decided to exclude the case of Beijing from the scope of GIS analysis due to the limited availability of relevant and comparable spatial data, leaving the example of Beijing as a reference. We have added a statement about it (page 4, Section 2.1, lines 175-177).

Comments 6: The article images are not uniform in size. It is recommended to modify the image sizes to make them more visually appealing.

Response 6: Thank you for the comment. We believe this referred mainly to figures 2, 3 and 4 (formerly numbered as 5, 6 and 7), which was not equal size despite presenting similar spatial data. We corrected their sizes and scale, as well as the map legend in order to make them uniform.

Comments 7: Some section titles are not numbered or do not comply with MDPI standards (for example, continuing to use '3.2.1' after '3.2.1').

Response 7: Thank you for pointing this out. We revised and corrected the numeration of chapters.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Thank you for addressing the comments in the review of the paper.