Contribution by Paola Mazzoglio (PM)

Heidi Kreibich is head of the working group “Flood risk and climate adaptation” at the Section Hydrology, German Research Centre for Geosciences GFZ. Heidi’s research is focused on flood risk assessment and mitigation with a background in Environmental engineering, Hydrology and Geography. Heidi is particularly interested in understanding and modelling flood damage processes and in human-flood interaction. She coordinates the IAHS Panta Rhei Working group “Changes in flood risk”.

PM. Can you tell us a little bit about your background and education? Was becoming a scientist your career plan when you were a student?

I studied environmental engineering at the Technical University of Berlin. Coming from a village in Bavaria, studying in the highly dynamic city of Berlin right after reunification opened up a new world for me. I had a wide range of interests, participated in independent student projects such as self-organised seminars on feminist environmental research and also completed internships in consulting companies, administration and research institutions. Above all, my study project during an Erasmus semester at Lancaster University, UK with Prof. Kevin Jones and my diploma thesis at CSIRO in Melbourne, Australia under the supervision of Dr. Rob Gillett awakened my passion for science and I decided to do a PhD and go into research.

PM. Which major challenge in the natural hazard field are you most interested in tackling?

I work in hydrology on hydrological extremes, mainly floods. The space-time dynamics of floods are determined by complex interactions between physical and human processes. Understanding the human-flood system and identifying and quantifying the influence of key drivers of change on flood risk is challenging (Kreibich et al., 2019). However, this knowledge is essential for the development of sustainable, adaptive flood risk management and climate change adaptation strategies (Kreibich et al., 2014). The challenge of understanding and modelling the dynamics of flood risk should be addressed in interdisciplinary teams of natural scientists, engineers and social scientists. The Panta Rhei initiative of the International Association of Hydrological Sciences has made great progress in interdisciplinary research on water during the last 10 years, but of course much more needs to be done.

PM. Several natural hazards are far from being properly understood, managed and mitigated. Lots of open questions still remain after centuries of research. How do you see the future of the natural hazard field?

The editors of the open access journal NHESS-Natural Hazards and Earth System Sciences, of which I am one, initiated the special issue “Perspectives on challenges and step changes for addressing natural hazards” and two surveys dedicated to this very question. The survey to which 350 natural hazard community members responded revealed that while the most common knowledge gaps are felt to be related to risk drivers, the step changes that the community felt were necessary related more to issues of wider stakeholder engagement, increased risk management and interdisciplinary working (Trogrlić et al., 2022). The survey, which included 122 female and non-binary scientists, found that promoting gender equality in natural hazard research and risk reduction planning has had too little success so far, with non-male scientists still a minority in the field. However, this gender bias needs to be overcome in order to develop a comprehensive overview of vulnerabilities and risks, as well as equitable and sustainable risk reduction strategies (Cigala et al., 2022).

PM. What technological advances do you think will be key for flood risk assessment over the future 10 years?

Risk assessment models that need to take into account a multitude of processes and feedbacks are data and computationally intensive (Vorogushyn et al., 2018). Therefore, I believe that two developments are particularly important for flood risk assessment, namely the use of data science approaches (e.g. the use of non-parametric, non-linear and probabilistic methods, data gap filling, etc.) and the use of improved computing power and speed (e.g. through GPU parallel processing, high-performance computing, etc.).

PM. You recently published in Nature a paper on “the challenge of unprecedented floods and droughts in risk management” that summarizes a huge research effort of the Panta Rhei Working Group (Kreibich et al., 2022). This work has shown that implementing risk management measures on the basis of the worst-case event ever experienced in a specific location is not enough to reduce the impacts of unprecedented future events. In your opinion, how can we take into account future extraordinary events in the design of structural and non-structural interventions?

In order to be better prepared for unprecedented future events, we should be more imaginative, assess worst-case scenarios and additional event impacts, and be critical of our own assumptions and models (Merz et al., 2021). The failure of structural and organisational protective measures should be imagined: What can happen if dikes break or warning chains do not work? It should also be considered where and under which conditions such unfavourable situations can arise that people die. One way to better understand extreme events is to reconstruct historical floods, i.e. events before systematic discharge measurements began. Such reconstructions were also available for the Ahr valley in Germany, which was severely affected by the 2021 flood, but were obviously not sufficiently taken into account in the creation of hazard maps.

PM. In this paper, you considered 45 pairs of events that occurred in the same areas. Among all, two success stories were examined. For these specific cases, even if the second event was more severe than the previous one, the damages were less. You identified an effective governance of risk and emergency management, a high investment in structural and non-structural measures, and improved early warning and real-time control systems as the possible strategies that reduced the impact. Unfortunately, most countries have limited funding to contrast the effects of climate change. If you have to choose only one strategy among these three, which one would you select? Do the event type (flood or drought) and the location influence your answer?

Since the failure of structural measures is very likely during unprecedented events, I consider the implementation of integrated risk management strategies that complement structural measures with non-structural ones to be most important. This strategy takes into account that defence systems can fail and prepares for unexpected crisis situations through spatial planning and private mitigation, e.g. through structural precautionary measures and responses triggered by early warning (Kreibich et al., 2015). Some private precautionary measures are cost-effective in various situations, and we could observe that such measures are very popular in Vietnam, for example (Chinh et al., 2016).

PM. During a disaster, people are used to make decisions that are based on a few simple rules or on previous experiences rather than evaluating the entirety of the information available. In your opinion, how can we educate people to make wise and self-protecting decisions during an emergency?

A prerequisite for wise and effective action before an event is long-term preparedness and reliable early warning with sufficient lead time. An impact-based forecast that predicts not only the amount of precipitation but also inundation areas and damage is particularly useful, especially if it is complemented by helpful advice on what to do (Merz et al., 2020). We were able to show, for example, that early warnings are only effective if people know what to do when they receive the warning. We also showed that preparedness is linked to knowing what to do when people receive a warning. Risk communication, training and (financial) support for private preparedness are thus effective in mitigating flood damage in two ways: via effective precautionary measures and more effective emergency measures (Kreibich et al. 2021, https://doi.org/10.1175/BAMS-D-20-0262.1).

About the author

Paola Mazzoglio is a PhD student at Politecnico di Torino working on geographically based approaches to the statistical analysis of rainfall extremes. She is also a teaching assistant at the same university. Paola is a member of the Blog Committee as part of the Young Hydrologic Society (YHS) board (2022-2023). Correspondence to paola.mazzoglio@polito.it.

References

Chinh, D.T., Bubeck, P., Dung, N.V., Kreibich, H. 2016. The 2011 flood event in the Mekong Delta: preparedness, response, damage and recovery of private households and small businesses. Disasters, 40: 753-778. https://doi.org/10.1111/disa.12171

Cigala, V., Roder, G., Kreibich, H. 2022. Invited perspectives: “Natural hazard management, professional development and gender equity: let’s get down to business”, Natural Hazards and Earth System Science, 22, 85–96. https://doi.org/10.5194/nhess-22-85-2022

Kreibich, H., Blauhut, V., Aerts, J.C.J.H., Bouwer, L.M., Van Lanen, H.A.J., Mejia, A., Mens, M., & Van Loon, A.F. 2019. How to improve attribution of changes in drought and flood impacts. Hydrological Sciences Journal, 64:1, 1-18. https://doi.org/10.1080/02626667.2018.1558367

Kreibich, H., Bubeck, P., Van Vliet, M. et al. 2015. A review of damage-reducing measures to manage fluvial flood risks in a changing climate. Mitigation and Adaptation Strategies for Global Change, 20, 967–989. https://doi.org/10.1007/s11027-014-9629-5

Kreibich, H., Hudson, P., Merz, B. 2021. Knowing what to do substantially improves the effectiveness of flood early warning. Bulletin of the American Meteorological Society, 102, 7, E1450-E1463. https://doi.org/10.1175/BAMS-D-20-0262.1

Kreibich, H., van den Bergh, J., Bouwer, L. et al. 2014. Costing natural hazards. Nature Climate Change, 4, 303–306. https://doi.org/10.1038/nclimate2182

Kreibich, H., Van Loon, A.F., Schröter, K. et al. 2022. The challenge of unprecedented floods and droughts in risk management. Nature 608, 80–86. https://doi.org/10.1038/s41586-022-04917-5

Merz, B., Kreibich, H., Thieken, A., Vorogushyn, S. 2021. Überraschende Hochwasserereignisse: Lehren für Risikoanalysen. – Notfallvorsorge: die Zeitschrift für Bevölkerungsschutz und Katastrophenhilfe, 52, 3, 19-23. https://gfzpublic.gfz-potsdam.de/rest/items/item_5008087_3/component/file_5008505/content

Merz, B., Kuhlicke, C., Kunz, M., Pittore, M., Babeyko, A., Bresch, D.N., Domeisen, D.I.V., Feser, F., Koszalka, I., Kreibich, H. et al. 2020. Impact forecasting to support emergency management of natural hazards. Reviews of Geophysics, 58, e2020RG000704. https://doi.org/10.1029/2020RG000704

Šakić Trogrlić, R., Donovan, A., and Malamud, B.D. 2022. Invited perspectives: Views of 350 natural hazard community members on key challenges in natural hazards research and the Sustainable Development Goals. Natural Hazards and Earth System Science, 22, 2771–2790. https://doi.org/10.5194/nhess-22-2771-2022

Vorogushyn, S., Bates, P.D., de Bruijn, K., Castellarin, A., Kreibich, H. et al. 2018. Evolutionary leap in large-scale flood risk assessment needed. WIREs Water, 5:e1266. https://doi.org/10.1002/wat2.1266