the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 18 Sep 2024
Assessing Flood Risk: Identifying Indicators and Indices for Period-Specific Flood Measures
Abstract. Flood risk assessment is pivotal for comprehending and mitigating flood impacts. Although various indicators and indices are employed for flood risk assessment, the precise selection criteria for these indicators, particularly, concerning their roles and applicability during flood periods, remain unclear. This paper seeks to address this gap by identifying indicators and indices crucial for determining appropriate measures tailored to different flood periods. We conducted a systematic literature review, focusing on articles utilizing the Analytic Hierarchy Process (AHP) methodology to evaluate indicators across diverse risk factors, including sensitivity. By analysing these studies, we identified the most frequently used indicators for each index and risk factor. The intricate interplay among indicators and risk factors necessitated a clear conceptual framework. Our findings offer recommendations for selecting risk indicators and indices aligned with specific actions and measures corresponding to distinct flood periods. By bridging this gap in understanding, our research contributes to enhancing flood risk assessment methodologies and informing effective mitigation strategies.
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RC1: 'Comment on egusphere-2024-2534', Anonymous Referee #1, 27 Sep 2024
I have now read the manuscript titled:” Assessing flood risk: identifying indicators and indices for period-specific flood measures”. In my opinion, the article has many significant drawbacks that undermine its clarity and overall quality.
General comments:
- The aim is not clear
- There are many inconsistencies in the presentation of the method and results
- Significant references are missing
- Critical view is missing from discussion and conclusions
Specific comments:
Title: The title does not represent the content. This is a “Review of indicators and indices for flood risk assessment”.
Abstract: The problem with review papers is that they have to be very well-focused (clearly delimited) and to have a specific purpose. Neither of the two is clear in the manuscript in my opinion. In the abstract, the gap that the authors are “bridging” (line 14) is not clear neither are the findings.
Introduction: This is a very good place to make some things clear. What do you mean with floods? Is this only river flood or also flash flood (or dynamic flooding) or even coastal flood? What do you mean by “flood periods”? This becomes clear in page 19 (too late).
Introduction: what do you mean by “alternative approaches” in line 32? What are their advantages and disadvantages? You can get some ideas/refer to this publication:
Papathoma-Köhle, M.: Vulnerability curves vs. vulnerability indicators: application of an indicator-based methodology for debris-flow hazards, Nat. Hazards Earth Syst. Sci., 16, 1771–1790, https://doi.org/10.5194/nhess-16-1771-2016, 2016
Introduction: (lines 38-40). Is this your own definition? These criteria (measurable, observable etc.) can be found in the book of Birkman Measuring Vulnerability to natural hazards. In my opinion, a quality check of your indicators through this criteria would be beneficial for the paper (see previous publication of Papathoma-Köhle). What is also missing is the definition of (vulnerability) indicators from Birkman. The reference is here:
Birkmann, J.: Indicators and criteria for measuring vulnerability: Theoretical bases and requirements. In J. Birkmann (Ed.),Measuring Vulnerability to Natural Hazards: Towards disaster resilient societies (S. 55-77). UNU Press, 2006.
Moreover, valuable information on indicators can be found here:
OECD. Handbook on Constructing Composite Indicators: Methodology and User Guide. (OECD Publications, Paris, 2008).
Introduction: you refer to the ambiguity among risk factors (line 95) that you do not really discuss in the manuscript. You should definitely refer to this paper-they do exactly that:
https://link.springer.com/article/10.1007/s11069-024-06643-9
Introduction: you focus on AHP. Why? What about other methods? What is better in AHP? Maybe saying “participatory methods” in general would be better. A reference about AHP should be added for the readers that do not know what it is.
Material and method: you explain in the conclusions why you limit the review to these years (2017 to 2022). The reason you give is limited resources which is not good enough to explain this limitation. What about recent papers (2023?). What has this with resources to do?
Material and methods: the title of 2.2 is wordy and not to the point.
Material and methods: (line 129) “an assessment was conducted”, which assessment? How? Which method did you use? Not clear.
Results: (line 140) you already wrote a lot about definitions in the introduction. Maybe you should move some text here and use the introduction to set the scene.
Results: Definitions from the UNDRR (2017) are totally missing! Here is the reference:
https://www.undrr.org/drr-glossary/terminology
Results: there is no critical view of the definitions. E.g. definitions of risk Ologunorisa and Maskrey-why are they different? Are they?
Results: vulnerability (lines 167-169): “damage curves for physical assets and indices for human well-being”. I do not agree. There are plenty of studies using indices for physical assets e.g.
Papathoma-Köhle, M., Schlögl, M. & Fuchs, S. Vulnerability indicators for natural hazards: an innovative selection and weighting approach. Sci Rep 9, 15026 (2019). https://doi.org/10.1038/s41598-019-50257-2
Results: Vulnerability: a discussion on the different vulnerability dimensions is needed here.
Results: Susceptibility/sensitivity. According to line 123 there are three factors of risk (vulnerability exposure and hazard) and vulnerability incorporates susceptibility/sensitivity and adaptive capacity. If this is part of vulnerability why is it in a separate subchapter, and where is adaptive capacity.
Table 1. the table would be better with a column providing the reference of each paper and a column showing the aim of each paper. The first column is not clear (what is this about?-I think it is about the aim of the study but it is not clear). An interesting piece of information would be to indicate whether the study is quantitative or qualitative and what is the risk metric.
3.3 Indices and indicators: what are the differences? The authors have to explain (we get an explanation in the figure caption-Fig 1). Yet, although according to the figure caption the indices are left, in the text they are called indicators (lines 229-230).
Figure 1: on the right side we can see the risk factors. However, the risk factors according to line 23 are 3 (hazard, vulnerability, exposure). Now they are five. Susceptibility is supposed to be part of the vulnerability (lines28). What about the “flood potential”? What is the difference to hazard? Where is the definition of flood potential in the “definition analysis” part?
Figure 1: Are these indices from specific publications or have you developed them yourselves? It is not clear.
Table 3. Is imperviousness an indicator? Is it measurable and observable? (see comment about quality criteria above). I think impreviousness is actually the result of a number of indicators (e.g. building material, building height, position of openings etc.).
Table 8. What is direct and inverse proportion? I do not agree that population density has a neutral effect during the response phase (by the way, I think that “phase” is a better word than period). Evacuation possibilities and methods are related to the population density. I also do not agree that the number of households is neutral in the pre-flood phase. It is very relevant for the total authorities and how they are going to prepare.
Table 9 and table 10: why the socio-economic index has now less indicators than before?
Table 9 is for the hazard, table 10 is for the exposure. What about vulnerability?
Discussion: parts of the discussion talk about the methodology. New information is coming in but there is no critical view of the findings which is what the discussion would be about. Also, limitations could be discussed here and not in the conclusions.
Discussion: according to the abstract, there should be some recommendations at the end, but there are not.
Conclusions: “the paper seeks to understand the ambiguity among risk factors”. I do not think that it does that. There is not enough discussion on this matter.
Conclusions (lines 461-462): “it was necessary to build a clear concept”-it is also not clear what is this concluding clear concept that has been developed. Lines 466-467: “the exhaustive definitional review”-it is not exhaustive since the terminology of the UNDRR is missing. Lines 474-476: “By focusing on…nature of flood risk”. This is not something new. There are plenty of studies focusing separately on hazard, vulnerability and (less) exposure. Finally, the last paragraph is about participatory methods and stakeholders, a topic that it is not adequately approached in the manuscript.
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RC2: 'Comment on egusphere-2024-2534', Anonymous Referee #2, 24 Nov 2024
Review Report:
MS No.: egusphere-2024-2534
MS type: Review article
Title - Assessing Flood Risk: Identifying Indicators and Indices for Period-Specific Flood Measures
This paper advances flood risk assessment by identifying critical indicators and indices for developing period-specific flood measures. Through a systematic literature review, the authors analyze studies that utilize the Analytic Hierarchy Process (AHP) methodology to evaluate risk indicators across factors such as hazard, vulnerability, and exposure. The study effectively classifies these indicators and their roles during pre-flood, during-flood, and post-flood periods, addressing gaps in understanding the dynamic roles of indicators in flood risk assessment methodologies. The alignment of indicators with specific flood periods provides valuable insights into assessing flood risk. However, several areas require attention to improve the quality of the manuscript.
Major Comments:
- The authors acknowledge the use of AI tools, such as ChatGPT, for language and grammar refinement. While the AI tool has enhanced the manuscript's vocabulary, the scientific flow and intended meaning are unclear in certain parts of the introduction. Improving the phrasing in the introduction would help clarify the study's objectives and strengthen the overall narrative.
- The formula for risk is repeated multiple times in the introduction, leading to redundancy. Consolidating the discussion of risk formulations into one cohesive paragraph and placing it in Section 3.1.1, where the authors conduct a definitional analysis of each risk factor, would streamline the narrative and improve clarity.
- While the paper emphasizes the benefits of AHP, it overlooks its limitations, such as subjectivity in weighting indicators and scalability challenges. Including a brief critique of AHP and suggesting ways to address these limitations, as identified during the literature review, would provide a more balanced perspective for readers.
- The rationale for selecting the time period from 2017 to 2022 is not adequately addressed. Limiting the study to this period excludes the conceptual evolution of risk, hazard, vulnerability, and exposure definitions provided by IPCC. Since the paper also highlights contextual differences in the definitions of flood factors, a synthesis of definitions from IPCC AR5 and AR6 would help present a unified and comprehensive perspective.
- While the authors mention exclusions during the review process, the rationale for excluding topics such as community perceptions and groundwater is unclear. Providing a brief explanation of why these topics were deemed irrelevant to the study would be helpful. For instance, explain how these topics differ from the selected indicators or indices in your framework.
- The methodology for categorizing indicators into different flood periods requires a more systematic explanation. For example, how were “positive” and “negative” effects determined? Providing quantitative or qualitative evidence to support such classifications would strengthen the methodology.
- Indicators such as slope and elevation are presented under multiple risk factors (e.g., hazard and vulnerability), leading to ambiguity. Clearly defining the criteria for assigning indicators to specific categories is crucial. For instance, clarify how slope impacts runoff as a hydrological factor while also influencing topographical vulnerability.
- Section 3.4 lacks a detailed explanation of how the indicators listed in Table 8 were categorized into different flood periods. Elaborating on the methodology for this categorization would enhance the paper’s credibility.
- The classification of geology and geomorphology as “during-flood” indicators appears counterintuitive, as they also play a role in pre-flood planning. Justifying this categorization based on the authors’ methodology or reconsidering their classification as pre-flood indicators would add clarity and consistency.
- While the study identifies primary indicators for each component, it does not elaborate on their practical implications for policymakers. Adding a subsection or paragraph to the discussion that details how these indicators can guide resource allocation, infrastructure development, or community-level interventions during each flood period would significantly enhance the manuscript’s relevance and impact.
- The statement in Line 471 about future research directions is generic and could be made more specific. Suggestions such as using AI/ML techniques for indicator prioritization, conducting regional comparisons of indicators, or integrating remote sensing and big data analytics for improved risk assessment would provide actionable and valuable insights for future work.
Minor comments and suggestions have been provided in the annotated manuscript attached.
The manuscript explores a critical area of flood risk assessment and has significant potential to contribute to the field. Addressing the comments above will improve its clarity, depth, and utility, ensuring greater impact for researchers and policymakers. Enhancing the methodology, justifying key decisions, and adding actionable insights for future research will elevate the manuscript’s overall quality.
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