Innovations in Best Practices: Approaches to Managing Urban Areas and Reducing Flood Risk in Reggio Calabria (Italy)

Round 1

Reviewer 1 Report

In this paper the authors show the results of the application of Storm Water Management Model (SWMM, provided from EPA) and MODCEL: An Integrated Cell Model For River Basin Simulation applied to urban area.
The authors perform information processing in Google Earth environment in order to obtain input information for the models considered.
Finally they report the results of flood reduction in absolute value (so I believe).
However, I believe the article lacks elements that can distinguish it as a research article, I think, rather, it may be a technical report of a comparative application of ready-made and unmodified softwares.
In fact, the authors have not developed any part of the models used and nor do they try to add new elements to improve the results, in fact they limit themselves to comparing some technologies already known.

Author Response

We have to disagree with Reviewer #1, when he/she says that the manuscript seems “technical report of a comparative application of ready-made and unmodified softwares”. At the same time, we also have to apologize, because probably, as proposed by the Reviewer, “the research design, questions, hypotheses and methods” must be improved.

We would like to clarify our intention in this answer and, as a consequence, we are also changing the way our objectives were stated in the manuscript.

We would like to stress that we are not comparing two different models. The general set up of our work starts with the recognition that several cities have incomplete topographical and/or hydrological data for calibrating urban flood models and this is a critical situation, since densely occupied territories, like the ones represented by cities, are difficult to interpret and demand integrated actions to reduce flood risks using limited available spaces.

In order to change the initial perception generated by our text, we changed the abstract, revised the introduction as a whole, and explicitly rephrased the objectives. This part of the new text is reproduced below:

“This paper intends to offer a framework to address urban flooding in a densely occupied urban watershed, where structural and non-structural measures are combined in a set of best practices to mitigate flood risks, including the remaining residual risks. An essential part of this framework relies on mathematical modeling, since cities represent complex environments that are difficult to interpret without modeling tools and usually demand integrated actions in space and time in order to address and reduce flood risks.

However, the general setup of the framework proposed here starts with the recognition that several cities have incomplete topographical and/or hydrological data for modeling urban flooding. This is a critical situation, since the lack of a proper data set for calibration purposes can provide little confidence in the results. It makes it difficult to be sure about design choices aimed to optimize urban flood solutions. Furthermore, these choices may imply costly adaptation measures in a context limited by the urbanization itself. The higher the uncertainty, the worse the decision process and the possible consequences.

In this context, we propose the combination of two models of different conceptions, in a redundant procedure, to build an envelope of results, creating a space of confidence. Then we explore LID measures within the limits imposed by urbanization and, lastly, we introduce a warning system strategy to reduce risks and improve resilience of a system that becomes safer to fail.

The methodological proposal will be built using an exploratory case study in Reggio Calabria, in southern Italy, and supported by mathematical modeling tools.

It is important to highlight that the watershed used in the case study is prone to flash floods due to morphological and climatic features and there are no measured data to precisely characterize flooding. The only available information refers to the identification of critical flooding points, with approximate flood depths and flooding extensions.

In this way, flood modeling will be performed by Storm Water Management Model (SWMM) and Urban Flow-Cell Model (MODCEL), aiming to produce more consistent results (although limited information for model calibration), by joining the capability to map system failures of SWMM and the surface flow representation, and its interaction with urban features of MODCEL. After validating the two models against each other, a systemic diagnosis will be produced, and flood risk control alternatives will be drawn using the models to offer a range of probable results for the proposed actions.

LID controls are taken as the basis for supporting the structural measures, seeking to increase the watershed naturalness (as much as possible, considering the dense urban occupation) and acting both at the urban area level and at the watershed scale. Non-structural measures will complement the structural ones and refer to flood mapping and the development of early warning systems, mainly focusing on the reorganization of city mobility and the definition of safe areas. Complementary non-structural actions help cities to coexist with floods in a more resilient way.”

Reviewer 2 Report

Barbaro et al. present a interesting paper about better practices to manage urban areas in order to reduce flood risk at southern Italy. There are some specific points to be solved:

1. I recommend a little change in the title: Innovations in best practices to manage urban areas and to reduce flood risk in Reggio Calabria (Italy)

 

2. The paper needs to follow a common structure: Introduction, Study Area, Methods, Results, Discussion, and Conclusions. With these clear changes, it will be more concise and direct.

 

3. Decimals must be with a point not comma. Please change along the manuscript and figures.

 

4. The Results and Discussion section is disproportionate compared with the Introduction and Methods sections. Please try to balance and bring some results mentioned in the Methodology section.

 

5. Please separate Results and Discussion, and really discuss your results with similar works from Italy, Europe and worldwide using similar methods.

 

6. Clarify the citations mentioned in the attached PDF.

 

7. Please clarify how you decide the Manning values, I gave you some citations to be added in this point.

 

8. I recommend an English native speaker review. This will improve your paper.

 

9. Detailed corrections in the attached PDF.

Author Response

We would like to thank Reviewer #2 for his/her contributions. Here are the answers point by point.

1) Reply: We would like to inform that we followed his suggestions and changed the title to “Innovations in best practices: approaches to managing urban areas and reducing flood risk in Reggio Calabria (Italy)”, also in accordance with the revision of the native English speaker.

2) Reply: We also changed the paper structure to: Introduction, Case Study, Materials and Methods, Results, Discussion and Conclusion. In this way the text is easier to follow and understand. The results that were initially presented in the Methodology section were re-organised in the Results section. All the discussion developed were placed in a new section called Discussion. In this way the analysis of the results could be done in a clearer and deeper way.

3) Reply: We inform that all the decimals are now with point not comma.

4) Reply: The Results and Discussion section has been separated into two parts and the sections have been balanced.

5) Reply: The Results and Discussions section has been separated into two parts and, at the beginning of the Discussion section, a detailed literature review of the main couplings between SWMM and other software and models has been added. Furthermore, we also clearly included the range of results obtained with the combined use of SWMM and MODCEL.

6) Reply: The literature review was revised and almost all the Reviewer’s suggestions were included. Some other additional references were also considered and included.

7) Reply: The methodology followed to assign the Manning coefficients to the various elements present in the study area is explained in paragraphs 4.1 and 4.2, in accordance with the indications present in the cited scientific literature.

8) Reply: The paper was sent to a native English speaker.

9) Reply: The detailed corrections indicated in the attached pdf have been made.

Reviewer 3 Report

The paper is very well written, easy to follow and understand clearly. The topic of your publication is very important for today's and future generations due to the sea level rises. More data could be gathered for following publications.

Author Response

We would like to thank Reviewer #3 for his/her comments. Considering that Reviewer #3 indicated that “the arguments and discussion of findings can be improved”, we revised the introduction, restated the objectives and reorganized the structure of the manuscript, individualising the Discussion section.

Round 2

Reviewer 1 Report

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Author Response

Dear Reviewer, many thanks for your comments which were very helpful to improve the manuscript.

Reviewer 2 Report

Thank you for the corrections that improved your paper.

Author Response

Dear Reviewer, many thanks for your comments which were very helpful to improve the manuscript.