Round 1

Reviewer 1 Report

The manuscript presents a rather simple zero-order quick assessment model for flood damage at the example of an flood event in Italy.

Overall, the effort to obtain rough estimates of the damage based on the affected area is commendable of of practical importance. Yet, the approach is rather exploratory and simple in terms of methodology, and I am under the impression that this manuscript does have more the format of a technical comment than a research article. I would like to also point out that the Guides for authors clearly state that "Authors should not unnecessarily divide their work into several related manuscripts, although short Communications of preliminary, but significant, results will be considered. "

My main suggestion for improvement concerns the claim by the authors that the model does work well. In my point of view, this is demonstrated only to some extent. A more rigorous validation in terms of model performance estimation by means of applying proper resampling and reporting the results in a more detailed way would be really beneficial here.

Additional comments are as follows:

• The introduction is rather short. Again, this is ok for a short communication, but I think there would be need to provide a better context in a research article. For instance, there are models for data-scarce regions (e.g. https://doi.org/10.1016/j.ijdrr.2021.102148;  https://doi.org/10.1111/jfr3.12736).
• Line 161: "Also, municipalities with a few claims (1-2 units)
  have been excluded as they are not significant for the model calibration." Suggest to avoid the term "significant" here, as this has a specific meaning in a statistical context.
• Line 199ff: This section should be streamlined to provide more concise information. Partially, this reads less like a methods section rather than a discussion of CEMS benefits and drawbacks. The section from line 189 onwards is about the establishment of the flooded area (S_0), but I think the authors kind of wander off from the main topic here too far, until the main point is reiterated down in line 242. I suggest to focus more concisely on the derivation of S_0 here.
• Around line 250: The assumption, that only the ground floor is affected is a strong one, but adequately stated as such.
• Figure 6: the points are difficult to distinguish. Maybe use some transparency in the fill and solid point outlines? (c.f. Figure 8, which is better to read).
• Results - model validation (around line 265): I would strongly welcome a more detailed model validation procedure and presentation of model validation results. For instance, cross-validation or some other resampling procedure would be beneficial, along with model performance metrics and e.g. a predicted versus observed plot.
• Figure  7: I find plots with secondary y-axis to be difficult, at least if no easy functional relationships exist between the two axis. The horizontal lines correspond to the primary y-axis, the percentages of the cumulative frequency are basically just floating around somehow.
• There seems to be a severe bias towards underestimation of damage. Is there an explanation for this clear bias?
• I suggest to use consistent color palettes throughout the manuscript.
• When looking at figure 8, I am not sure is the suggested quasi-linear relationship on the log-log plane holds. There seems to be a convex relationship here. Especially points a the lower tails (low estimated damage, low flooded surface) seem to deviate here.
• Figure 10: The red dot for "levee failure" is difficult to spot, as the buildings are also red.
• Figure 11: "observed values" doesn't really make sense if both x-axis and y-axis are labelled  as "estimated"?

Author Response

The authors want to thank the reviewer for the time and attention dedicated to the work. It emerged helpful insights and stimulating suggestions that certainly will enrich the contents of the article. In the attached file, we will present our comments on what the reviewer reported. Changes in the text of the paper have been implemented accordingly and highlighted in yellow.

Author Response File: Author Response.pdf

Reviewer 2 Report

Reviewer

 

Water

 

Manuscript Number: ID 1508910

 

Title: Improvements and operational application of a zero-order quick assessment model for flood damage: a case study in Italy

 

 

As requested, I have reviewed the above-titled paper for potential publication in the Water- MDPI Journal. I divided my comments in the sections presented as follows.

 

 

Contribution

This paper proposes the analysis of assessment of flood damage to residential buildings for the Po-Venetian plain area (Northern Italy). A case study related to a flood event that took place in December, 2020 (4-8 December) was examined (Emilia-Romagna region was used for validation). A previous and similar study has been conducted for South Italy.  

 

A quite simple zero-order regression model for estimating the total damage (D) (dependent variable) based on the residential flooded area footprint (F) (independent variable). The evaluation of the performance is based on a log-log graphical adjustment for a power-law relationship. When results are compared between the previous study (South Italy) and the present study (Northern Italy), the exponent (m) is the same for both cases, while changes are identified in the coefficient of intercept (s).  Some explanation is provided by the authors for such difference in terms of the type of occupation and type of construction.

 

The authors also refer to the use of remotely sensed data, however that information is not effectively used or if used not clearly shown. The authors refer to database collected by the National Fire Corps by using low-altitude all-weather helicopter GPS surveys

 

In addition, calibration e validation procedures for two sets of municipalities have been conducted across Italy, as better shown in the previous published paper. Some information (Mfs, Ar and Fa)  for such modeling approach has been raised by means of data from censored areas (dataset from 2011) monitored across Italy.

 

Moreover, the authors indicate that the proposed model is not to compete with more complex or sophisticated models, however the authors do not provide a broad overview with respect to the different alternatives and degree of success and in-depth discussion about  limitations.

 

The reason-why adopted by the authors is based on the fact that the proposed model is a simple and operational alternative to estimate damage and costs associated for a flooded area. How to approach such challenge and to quantify losses and damages is the key issue treated by the authors in this manuscript.

 

The authors claimed in the previous published paper to be an original contribution. Such original contribution is not that clear in the present proposed manuscript 

 

There are several points to be discussed and to be adequately understood with respect to the proposed zero-order order quick assessment model for flood damage not necessarily properly accounted for or explained  thoroughly  neither in the previous published paper (South Italy) nor for the present proposed manuscript (Northern Italy).

 

In general, the text is fairly presented in order that the reader can follow the main idea of the manuscript with some figures and tables. However the text requires to be fully revised and better organized with ideas and concepts clearly exposed, jointly with a broad and updated literature review. Assumptions should be clearly presented along the manuscript. Figures and Tables need to be fully revised. Methodological approaches are neither fully nor adequately reported. There are several gaps along the text. Supplementary Figures are important to understand the work flow adopted along the manuscript and corresponding assumptions and results. Some further comments are going to be raised in the next section with respect to the points raised

 

Therefore, the more specific comments and questions regarding the manuscript paper are going to be presented jointly with the evaluation of the contribution of the manuscript in the next section. They are provided below with more details with respect to the methodological approach. I think it would be interesting to have some feedback from the authors and also to have fully revised version of the text in order to better refer to the points I will raise in the next paragraphs. That might also lead to explore or reflect about different scenarios still not well and thoroughly explored by the authors in the proposed manuscript but that deserves attention.

Please, see further comments in the attached file. 

Comments for author File: Comments.pdf

Author Response

The authors want to thank the reviewer for the time and attention dedicated to the work. It emerged helpful insights and stimulating suggestions that certainly will enrich the contents of the article. In the attached file, we will present our comments on what the reviewer reported. Changes in the text of the paper have been implemented accordingly and highlighted in yellow.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

I would like to thank the authors for considering the comments of both reviewers, and providing adequate amendments and responses.

Some of the points raised in the initial review still hold:

• This manuscript reads more like a technical comment than a research article, as it is really application-oriented and the scientific novelty is rather low.
• I still think that cross-validation or some other resampling procedure would be beneficial to obtain a more robust evaluation of the model, but a simple train-test split is probably fine as well.
• I also think that a more consistent design of figures would be nice (e.g. consistent use of colors, consistent design of legends, consistent font types and font sizes).

However, I feel that all of these are basically editorial choices. I therefore conclude that the manuscript can be published in its current form, subject to some minor typos and a last spell check (e.g. "Here, present the use of ..." in line 12, "Ha instead of HA in line 381, etc.)

Author Response

The authors would like to thank for your revision. A double check for typos has been done and changes are marked up using the “Track Changes”.

Kind regards.

Reviewer 2 Report

Reviewer

 

Water

 

Manuscript Number: ID 1508910-V2

 

Title: Improvements and operational application of a zero-order quick assessment model for flood damage: a case study in Italy

 

 

As requested, I have reviewed the revised version of the above-titled paper for potential publication in the Water- MDPI Journal. I divided my comments in the sections presented as follows.

 

 

Contribution

This paper proposes the analysis of assessment of flood damage to residential buildings for the Po-Venetian plain area (Northern Italy). A case study related to a flood event that took place in December, 2020 (4-8 December) was examined (Emilia-Romagna region was used for validation). A previous and similar study has been conducted for South Italy.  

 

A quite simple zero-order regression model for estimating the total damage (D) (dependent variable) based on the residential flooded area footprint (F) (independent variable). The evaluation of the performance is based on a log-log graphical adjustment for a power-law relationship. When results are compared between the previous study (South Italy) and the present study (Northern Italy), the exponent (m) is the same for both cases, while changes are identified in the coefficient of intercept (s).  Some explanation is provided by the authors for such difference in terms of the type of occupation and type of construction.

 

In addition, calibration e validation procedures for two sets of municipalities have been conducted across Italy, as better shown in the previous published paper. Some information (Mfs, Ar and Fa)  for such modeling approach has been raised by means of data from censored areas monitored across Italy.

 

Moreover, the authors indicate that the proposed model is not to compete with more complex or sophisticated models. In this new version of the manuscript, the authors added some more comments with respect to the limitations and assumptions adopted in the modeling approach.

 

The reason-why adopted by the authors is based on the fact that the proposed model is a simple and operational alternative to estimate damage and costs associated for a flooded area. How to approach such challenge and to quantify losses and damages is the key issue treated by the authors in this manuscript.

 

The authors claimed in the previous published paper the modeling approach to be an original contribution. The original contribution in this new manuscript is more related to the case study adopted, which is different from the one presented in the previous paper, focusing in a different part of Italy. Somehow, both case studies (previous paper – South Italy and this one – Northern Italy) are complementary. The same proposed zero-order order quick assessment model is used for flood damage assessment.

 

In general, the text is fairly presented in order that the reader can follow the main idea of the manuscript with some figures and tables. There are a couple of points in the new version that should be revised by the authors. Further comments are going to be raised in the next section.

 

I found the manuscript has an interesting goal to be pursued and presents the conditions to be published in the Water  MDPI Journal.

Please, see further comments in the attached file. 

Comments for author File: Comments.pdf

Author Response

The authors would like to thank for your useful comments and revision. We have worked on the text according to all of your suggestions. Changes have been marked up using the “Track Changes” function. 

Kind regards.