TY - JOUR A1 - Surminski, Swenja A1 - Thieken, Annegret T1 - Promoting flood risk reduction BT - the role of insurance in Germany and England JF - Earth's Future N2 - Improving society's ability to prepare for, respond to and recover from flooding requires integrated, anticipatory flood risk management (FRM). However, most countries still focus their efforts on responding to flooding events if and when they occur rather than addressing their current and future vulnerability to flooding. Flood insurance is one mechanism that could promote a more ex ante approach to risk by supporting risk reduction activities. This paper uses an adapted version of Easton's System Theory to investigate the role of insurance for FRM in Germany and England. We introduce an anticipatory FRM framework, which allows flood insurance to be considered as part of a broader policy field. We analyze if and how flood insurance can catalyze a change toward a more anticipatory approach to FRM. In particular we consider insurance's role in influencing five key components of anticipatory FRM: risk knowledge, prevention through better planning, property‐level protection measures, structural protection and preparedness (for response). We find that in both countries FRM is still a reactive, event‐driven process, while anticipatory FRM remains underdeveloped. Collaboration between insurers and FRM decision‐makers has already been successful, for example in improving risk knowledge and awareness, while in other areas insurance acts as a disincentive for more risk reduction action. In both countries there is evidence that insurance can play a significant role in encouraging anticipatory FRM, but this remains underutilized. Effective collaboration between insurers and government should not be seen as a cost, but as an investment to secure future insurability through flood resilience. KW - flooding KW - insurance KW - governance KW - risk reduction Y1 - 2017 U6 - https://doi.org/10.1002/2017EF000587 SN - 2328-4277 VL - 5 SP - 979 EP - 1001 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Vogel, Kristin A1 - Ozturk, Ugur A1 - Riemer, Adrian A1 - Laudan, Jonas A1 - Sieg, Tobias A1 - Wendi, Dadiyorto A1 - Agarwal, Ankit A1 - Roezer, Viktor A1 - Korup, Oliver A1 - Thieken, Annegret T1 - Die Sturzflut von Braunsbach am 29. Mai 2016 – Entstehung, Ablauf und Schäden eines „Jahrhundertereignisses“ T1 - The Braunsbach Flashflood of Mai 29th, 2016-Origin, Pathways and Impacts of an Extreme Hydro-Meteorological Event BT - Teil 2: Geomorphologische Prozesse und Schadensanalyse BT - Part 2: Geomorphological Processes and Damage Analysis JF - Hydrologie und Wasserbewirtschaftung N2 - Am Abend des 29. Mai 2016 wurde der Ort Braunsbach im Landkreis Schwäbisch-Hall (Baden-Württemberg) von einer Sturzflut getroffen, bei der mehrere Häuser stark beschädigt oder zerstört wurden. Die Sturzflut war eine der Unwetterfolgen, die im Frühsommer 2016 vom Tiefdruckgebiet Elvira ausgelöst wurden. Der vorliegende Bericht ist der zweite Teil einer Doppelveröffentlichung, welche die Ergebnisse zur Untersuchung des Sturzflutereignisses im Rahmen des DFG-Graduiertenkollegs “Naturgefahren und Risiken in einer sich verändernden Welt” (NatRiskChange, GRK 2043/1) der Universität Potsdam präsentiert. Während Teil 1 die meteorologischen und hydrologischen Ereignisse analysiert, fokussiert Teil 2 auf die geomorphologischen Prozesse und die verursachten Gebäudeschäden. Dazu wurden Ursprung und Ausmaß des während des Sturzflutereignisses mobilisierten und in den Ort getragenen Materials untersucht. Des Weiteren wurden zu 96 betroffenen Gebäuden Daten zum Schadensgrad sowie Prozess- und Gebäudecharakteristika aufgenommen und ausgewertet. Die Untersuchungen zeigen, dass bei der Betrachtung von Hochwassergefährdung die Berücksichtigung von Sturzfluten und ihrer speziellen Charakteristika, wie hoher Feststofftransport und sprunghaftes Verhalten insbesondere in bebautem Gelände, wesentlich ist, um effektive Schutzmaßnahmen ergreifen zu können. N2 - A severe flash flood event hit the town of Braunsbach (Baden-Wurttemberg, Germany) on the evening of May 29, 2016, heavily damaging and destroying several dozens of buildings. It was only one of several disastrous events in Central Europe caused by the low-pressure system "Elvira". The DFG Graduate School "Natural hazards and risks in a changing world" (NatRiskChange, GRK 2043/1) at the University of Potsdam investigated the Braunsbach flash flood as a recent showcase for catastrophic events triggered by severe weather. This contribution is part two of a back-to-back publication on the results of this storm event. While part 1 analyses the meteorological and hydrological situation, part 2 concentrates on the geomorphological aspects and damage to buildings. The study outlines the origin and amount of material that was mobilized and transported into the town by the flood, and analyses damage data collected for 96 affected buildings, describing the degree of impact, underlying processes, and building characteristics. Due to the potentially high sediment load of flash floods and their non-steady and non-uniform flow especially in built-up areas, the damaging processes differ from those of clear water floods. The results underline the need to consider flash floods and their specific behaviour in flood hazard assessments. KW - flash flood KW - flood risk KW - damaging processes KW - debris flow KW - erosion KW - landslides KW - Braunsbach KW - Sturzflut KW - Hochwassergefährdung KW - Schadensprozesse KW - Erosion KW - Hangrutschungen Y1 - 2017 U6 - https://doi.org/10.5675/HyWa_2017,3_2 SN - 1439-1783 VL - 61 IS - 3 SP - 163 EP - 175 PB - Bundesanst. für Gewässerkunde CY - Koblenz ER - TY - JOUR A1 - Koc, Gamze A1 - Thieken, Annegret T1 - The relevance of flood hazards and impacts in Turkey BT - what can be learned from different disaster loss databases? JF - Natural hazards : journal of the International Society for the Prevention and Mitigation of Natural Hazards N2 - Turkey has been severely affected by many natural hazards, in particular earthquakes and floods. Especially over the last two decades, these natural hazards have caused enormous human and economic damage. Although there is a large body of literature on earthquake hazards and risks in Turkey, comparatively little is known about flood hazards and risks. Therefore, this study aims to investigate the severity of flooding in comparison with other natural hazards in Turkey and to analyse the flood patterns by providing an overview of the temporal and spatial distribution of flood losses. These will act as a metric for the societal and economic impacts of flood hazards in Turkey. For this purpose, Turkey Disaster Database (TABB) was used for the years 1960-2014. As input for more detailed event analyses, the most severe flood events in Turkey for the same time interval will also be retrieved. Sufficiency of the TABB database to achieve the main aim of the study in terms of data quality and accuracy was also discussed. The TABB database was analysed and reviewed through comparison, mainly with the Emergency Events Database (EM-DAT), the Global Active Archive of Large Flood Events-Dartmouth Flood Observatory database, news archives and the scientific literature, with a focus on listing the most severe flood event. The comparative review of these data sources reveals big mismatches in the flood data, i.e. the reported number of events, number of affected people and economic loss all differ dramatically. Owing to the fact that the TABB is the only disaster loss database for Turkey, it is important to explore the reasons for the mismatches between TABB and the other sources with regard to aspects of accuracy and data quality. Therefore, biases and fallacies in the TABB loss data are also discussed. The comparative TABB database analyses show that large mismatches between global and national databases can occur. Current global and national databases for monitoring losses from national hazards suffer from a number of limitations, which in turn could lead to misinterpretations of the loss data. Since loss data collection is gaining more and more attention, e.g. in the Sendai Framework for Disaster Risk Reduction 2015-2030, this study offers a framework for developing guidelines for the Turkey Disaster Database (TABB), implications on how to standardize national loss databases and implement across the other hazard events in Turkey. KW - Historic natural hazards KW - Floods KW - Disaster loss databases KW - Flood impacts KW - Turkey Y1 - 2017 U6 - https://doi.org/10.1007/s11069-017-3134-6 SN - 0921-030X SN - 1573-0840 VL - 91 IS - 1 SP - 375 EP - 408 PB - Springer CY - New York ER - TY - JOUR A1 - Thieken, Annegret T1 - Contributions of flood insurance toeEnhance resilience-findings from Germany BT - Findings from Germany JF - Urban Disaster Resilience and Security N2 - In 2002, a severe flood caused financial losses of EUR 11.6 billion in Germany and triggered many changes in flood risk management. This chapter focuses on flood insurance, which is a voluntary supplementary insurance in Germany: it is explored how flood insurance has contributed to enhance resilience of flood-prone residents. The analyses are based on empirical data collected by post-event surveys in the federal states of Saxony and Bavaria and refer to the three pillars upon which the concept of flood resilience usually builds in the natural hazards context: recovery, adaptive capacity and resistance. Overall, the penetration of flood insurance has increased since 2002 and there is strong empirical evidence that losses of insured residents are more often and better compensated than those of uninsured despite the provision of governmental financial disaster assistance after big floods. This facilitation of recovery is, however, not the only contribution to flood resilience. Insured residents tend to invest more in further flood mitigation measures at their properties than uninsured. Obviously, flood insurance is embedded in a complex safety strategy of property owners that needs more investigation in order to be addressed more effectively in risk communication and integrated risk management strategies. KW - Flood losses KW - Recovery KW - Climate change adaptation Saxony KW - Bavaria Y1 - 2017 SN - 978-3-319-68606-6 SN - 978-3-319-68605-9 U6 - https://doi.org/10.1007/978-3-319-68606-6_9 SN - 2365-757X SP - 129 EP - 144 PB - Springer CY - Cham ER - TY - GEN A1 - Rözer, Viktor A1 - Müller, Meike A1 - Bubeck, Philip A1 - Kienzler, Sarah A1 - Thieken, Annegret A1 - Pech, Ina A1 - Schröter, Kai A1 - Buchholz, Oliver A1 - Kreibich, Heidi T1 - Coping with pluvial floods by private households N2 - Pluvial floods have caused severe damage to urban areas in recent years. With a projected increase in extreme precipitation as well as an ongoing urbanization, pluvial flood damage is expected to increase in the future. Therefore, further insights, especially on the adverse consequences of pluvial floods and their mitigation, are needed. To gain more knowledge, empirical damage data from three different pluvial flood events in Germany were collected through computer-aided telephone interviews. Pluvial flood awareness as well as flood experience were found to be low before the respective flood events. The level of private precaution increased considerably after all events, but is mainly focused on measures that are easy to implement. Lower inundation depths, smaller potential losses as compared with fluvial floods, as well as the fact that pluvial flooding may occur everywhere, are expected to cause a shift in damage mitigation from precaution to emergency response. However, an effective implementation of emergency measures was constrained by a low dissemination of early warnings in the study areas. Further improvements of early warning systems including dissemination as well as a rise in pluvial flood preparedness are important to reduce future pluvial flood damage. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 355 KW - pluvial floods KW - surface water flooding KW - emergency response KW - early warning KW - preparedness KW - damage KW - mitigation Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-400465 ER - TY - GEN A1 - Kellermann, Patric A1 - Bubeck, Philip A1 - Kundela, Günther A1 - Dosio, Alessandro A1 - Thieken, Annegret T1 - Frequency analysis of critical meteorological conditions in a changing climate BT - assessing future implications for railway transportation in Austria N2 - Meteorological extreme events have great potential for damaging railway infrastructure and posing risks to the safety of train passengers. In the future, climate change will presumably have serious implications on meteorological hazards in the Alpine region. Hence, attaining insights on future frequencies of meteorological extremes with relevance for the railway operation in Austria is required in the context of a comprehensive and sustainable natural hazard management plan of the railway operator. In this study, possible impacts of climate change on the frequencies of so-called critical meteorological conditions (CMCs) between the periods 1961-1990 and 2011-2040 are analyzed. Thresholds for such CMCs have been defined by the railway operator and used in its weather monitoring and early warning system. First, the seasonal climate change signals for air temperature and precipitation in Austria are described on the basis of an ensemble of high-resolution Regional Climate Model (RCM) simulations for Europe. Subsequently, the RCM-ensemble was used to investigate changes in the frequency of CMCs. Finally, the sensitivity of results is analyzed with varying threshold values for the CMCs. Results give robust indications for an all-season air temperature rise, but show no clear tendency in average precipitation. The frequency analyses reveal an increase in intense rainfall events and heat waves, whereas heavy snowfall and cold days are likely to decrease. Furthermore, results indicate that frequencies of CMCs are rather sensitive to changes of thresholds. It thus emphasizes the importance to carefully define, validate, andif neededto adapt the thresholds that are used in the weather monitoring and warning system of the railway operator. For this, continuous and standardized documentation of damaging events and near-misses is a pre-requisite. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 358 KW - climate change KW - critical meteorological condition KW - frequency analysis KW - natural hazard management KW - railway transportation Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-400505 ER - TY - CHAP A1 - López-Tarazón, José Andrés A1 - Bronstert, Axel A1 - Thieken, Annegret A1 - Petrow, Theresia ED - López-Tarazón, José Andrés ED - Bronstert, Axel ED - Thieken, Annegret ED - Petrow, Theresia T1 - International symposium on the effects of global change on floods, fluvial geomorphology and related hazards in mountainous rivers T2 - Book of Abstracts N2 - Both Alpine and Mediterranean areas are considered sensitive to so-called global change, considered as the combination of climate and land use changes. All panels on climate evolution predict future scenarios of increasing frequency and magnitude of floods which are likely to lead to huge geomorphic adjustments of river channels so major metamorphosis of fluvial systems is expected as a result of global change. Such pressures are likely to give rise to major ecological and economic changes and challenges that governments need to address as a matter of priority. Changes in river flow regimes associated with global change are therefore ushering in a new era, where there is a critical need to evaluate hydro-geomorphological hazards from headwaters to lowland areas (flooding can be not just a problem related to being under the water). A key question is how our understanding of these hazards associated with global change can be improved; improvement has to come from integrated research which includes the climatological and physical conditions that could influence the hydrology and sediment generation and hence the conveyance of water and sediments (including the river’s capacity, i.e. amount of sediment, and competence, i.e. channel deformation) and the vulnerabilities and economic repercussions of changing hydrological hazards (including the evaluation of the hydro-geomorphological risks too). Within this framework, the purpose of this international symposium is to bring together researchers from several disciplines as hydrology, fluvial geomorphology, hydraulic engineering, environmental science, geography, economy (and any other related discipline) to discuss the effects of global change over the river system in relation with floods. The symposium is organized by means of invited talks given by prominent experts, oral lectures, poster sessions and discussion sessions for each individual topic; it will try to improve our understanding of how rivers are likely to evolve as a result of global change and hence address the associated hazards of that fluvial environmental change concerning flooding. Four main topics are going to be addressed: - Modelling global change (i.e. climate and land-use) at relevant spatial (regional, local) and temporal (from the long-term to the single-event) scales. - Measuring and modelling river floods from the hydrological, sediment transport (both suspended and bedload) and channel morphology points of view at different spatial (from the catchment to the reach) and temporal (from the long-term to the single-event) scales. - Evaluation and assessment of current and future river flooding hazards and risks in a global change perspective. - Catchment management to face river floods in a changing world. We are very pleased to welcome you to Potsdam. We hope you will enjoy your participation at the International Symposium on the Effects of Global Change on Floods, Fluvial Geomorphology and Related Hazards in Mountainous Rivers and have an exciting and profitable experience. Finally, we would like to thank all speakers, participants, supporters, and sponsors for their contributions that for sure will make of this event a very remarkable and fruitful meeting. We acknowledge the valuable support of the European Commission (Marie Curie Intra-European Fellowship, Project ‘‘Floodhazards’’, PIEF-GA-2013-622468, Seventh EU Framework Programme) and the Deutschen Forschungsgemeinschaft (Research Training Group “Natural Hazards and Risks in a Changing World” (NatRiskChange; GRK 2043/1) as the symposium would not have been possible without their help. Without your cooperation, this symposium would not be either possible or successful. KW - natural hazards KW - mountainous rivers KW - floods KW - global change KW - geomorphology Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-396922 ER - TY - JOUR A1 - Kreibich, Heidi A1 - Di Baldassarre, Giuliano A1 - Vorogushyn, Sergiy A1 - Aerts, Jeroen C. J. H. A1 - Apel, Heiko A1 - Aronica, Giuseppe T. A1 - Arnbjerg-Nielsen, Karsten A1 - Bouwer, Laurens M. A1 - Bubeck, Philip A1 - Caloiero, Tommaso A1 - Chinh, Do T. A1 - Cortes, Maria A1 - Gain, Animesh K. A1 - Giampa, Vincenzo A1 - Kuhlicke, Christian A1 - Kundzewicz, Zbigniew W. A1 - Llasat, Maria Carmen A1 - Mard, Johanna A1 - Matczak, Piotr A1 - Mazzoleni, Maurizio A1 - Molinari, Daniela A1 - Dung, Nguyen V. A1 - Petrucci, Olga A1 - Schröter, Kai A1 - Slager, Kymo A1 - Thieken, Annegret A1 - Ward, Philip J. A1 - Merz, Bruno T1 - Adaptation to flood risk BT - Results of international paired flood event studies JF - Earth's Future N2 - As flood impacts are increasing in large parts of the world, understanding the primary drivers of changes in risk is essential for effective adaptation. To gain more knowledge on the basis of empirical case studies, we analyze eight paired floods, that is, consecutive flood events that occurred in the same region, with the second flood causing significantly lower damage. These success stories of risk reduction were selected across different socioeconomic and hydro-climatic contexts. The potential of societies to adapt is uncovered by describing triggered societal changes, as well as formal measures and spontaneous processes that reduced flood risk. This novel approach has the potential to build the basis for an international data collection and analysis effort to better understand and attribute changes in risk due to hydrological extremes in the framework of the IAHSs Panta Rhei initiative. Across all case studies, we find that lower damage caused by the second event was mainly due to significant reductions in vulnerability, for example, via raised risk awareness, preparedness, and improvements of organizational emergency management. Thus, vulnerability reduction plays an essential role for successful adaptation. Our work shows that there is a high potential to adapt, but there remains the challenge to stimulate measures that reduce vulnerability and risk in periods in which extreme events do not occur. KW - flooding KW - vulnerability KW - global environmental change KW - adaptation Y1 - 2017 U6 - https://doi.org/10.1002/2017EF000606 SN - 2328-4277 VL - 5 SP - 953 EP - 965 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Vogel, Kristin A1 - Weise, Laura A1 - Schröter, Kai A1 - Thieken, Annegret T1 - Identifying Driving Factors in Flood-Damaging Processes Using Graphical Models JF - Water resources research N2 - Flood damage estimation is a core task in flood risk assessments and requires reliable flood loss models. Identifying the driving factors of flood loss at residential buildings and gaining insight into their relations is important to improve our understanding of flood damage processes. For that purpose, we learn probabilistic graphical models, which capture and illustrate (in-)dependencies between the considered variables. The models are learned based on postevent surveys with flood-affected residents after six flood events, which occurred in Germany between 2002 and 2013. Besides the sustained building damage, the survey data contain information about flooding parameters, early warning and emergency measures, property-level mitigation measures and preparedness, socioeconomic characteristics of the household, and building characteristics. The analysis considers the entire data set with a total of 4,468 cases as well as subsets of the data set partitioned into single flood events and flood types: river floods, levee breaches, surface water flooding, and groundwater floods, to reveal differences in the damaging processes. The learned networks suggest that the flood loss ratio of residential buildings is directly influenced by hydrological and hydraulic aspects as well as by building characteristics and property-level mitigation measures. The study demonstrates also that for different flood events and process types the building damage is influenced by varying factors. This suggests that flood damage models need to be capable of reproducing these differences for spatial and temporal model transfers. KW - flood loss KW - Bayesian Network KW - Markov Blanket KW - vulnerability KW - Germany Y1 - 2018 U6 - https://doi.org/10.1029/2018WR022858 SN - 0043-1397 SN - 1944-7973 VL - 54 IS - 11 SP - 8864 EP - 8889 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Bubeck, Philip A1 - Botzen, W. J. Wouter A1 - Laudan, Jonas A1 - Aerts, Jeroen C. J. H. A1 - Thieken, Annegret T1 - Insights into flood-coping appraisals of protection motivation theory BT - Empirical evidence from Germany and France JF - Risk analysis N2 - Protection motivation theory (PMT) has become a popular theory to explain the risk-reducing behavior of residents against natural hazards. PMT captures the two main cognitive processes that individuals undergo when faced with a threat, namely, threat appraisal and coping appraisal. The latter describes the evaluation of possible response measures that may reduce or avert the perceived threat. Although the coping appraisal component of PMT was found to be a better predictor of protective intentions and behavior, little is known about the factors that influence individuals’ coping appraisals of natural hazards. More insight into flood-coping appraisals of PMT, therefore, are needed to better understand the decision-making process of individuals and to develop effective risk communication strategies. This study presents the results of two surveys among more than 1,600 flood-prone households in Germany and France. Five hypotheses were tested using multivariate statistics regarding factors related to flood-coping appraisals, which were derived from the PMT framework, related literature, and the literature on social vulnerability. We found that socioeconomic characteristics alone are not sufficient to explain flood-coping appraisals. Particularly, observational learning from the social environment, such as friends and neighbors, is positively related to flood-coping appraisals. This suggests that social norms and networks play an important role in flood-preparedness decisions. Providing risk and coping information can also have a positive effect. Given the strong positive influence of the social environment on flood-coping appraisals, future research should investigate how risk communication can be enhanced by making use of the observed social norms and network effects. KW - Coping appraisal KW - floods KW - protection motivation theory (PMT) KW - risk communication KW - social vulnerability Y1 - 2018 U6 - https://doi.org/10.1111/risa.12938 SN - 0272-4332 SN - 1539-6924 VL - 38 IS - 6 SP - 1239 EP - 1257 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Natho, Stephanie A1 - Thieken, Annegret T1 - Implementation and adaptation of a macro-scale method to assess and monitor direct economic losses caused by natural hazards JF - International Journal of Disaster Risk Reduction N2 - As one of the 195 member countries of the United Nations, Germany signed the Sendai Framework for Disaster Risk Reduction 2015-2030 (SFDRR). Among other targets, the SFDRR aims at reducing direct economic losses caused by natural hazards by 2030. The United Nations Office for Disaster Risk Reduction (UNISDR) has hence proposed a methodology for estimating direct economic losses per event and country, based on experiences from developing countries. Since its usability in industrialized countries is unknown, this study presents the first implementation and validation of this approach in Germany. The methodology was tested for the three costliest natural hazard types in Germany, i.e. floods, wind and hail storms, considering 12 case studies between 1984 and 2016. Although the event-specific input data requirements are restricted to the number of damaged or destroyed units per sector, incomplete event documentations did not allow a full validation of all sectors necessary to describe the total direct economic loss. New modules (cars, forestry, paved roads, housing contents and overall costs of urban infrastructure) were developed to better adapt this methodology to German conditions. Whereas the original UNISDR methodology both over-and underestimates the losses of the tested events by a wide margin, the adapted methodology is able to calculate losses accounting well for all event types except for flash floods. Hence, this approach serves as a good starting point for macro-scale loss estimations. By implementing this approach into damage and event documentation and reporting standards, a consistent monitoring of the SFDRR could be achieved. KW - Germany KW - Direct economic loss KW - Natural hazards KW - Flood KW - Storm KW - Hail KW - Loss modelling Y1 - 2018 U6 - https://doi.org/10.1016/j.ijdrr.2018.03.008 SN - 2212-4209 VL - 28 SP - 191 EP - 205 PB - Elsevier CY - Amsterdam ER - TY - RPRT A1 - Thieken, Annegret A1 - Dierck, Julia A1 - Dunst, Lea A1 - Göpfert, Christian A1 - Heidenreich, Anna A1 - Hetz, Karen A1 - Kern, Julia A1 - Kern, Kristine A1 - Lipp, Torsten A1 - Lippert, Cordine A1 - Meves, Monika A1 - Niederhafner, Stefan A1 - Otto, Antje A1 - Rohrbacher, Christian A1 - Schmidt, Katja A1 - Strate, Leander A1 - Stumpp, Inga A1 - Walz, Ariane T1 - Urbane Resilienz gegenüber extremen Wetterereignissen – Typologien und Transfer von Anpassungsstrategien in kleinen Großstädten und Mittelstädten (ExTrass) BT - Verbundvorhaben „Zukunftsstadt“ (Definitionsprojekt) N2 - Weltweit verursachen Städte etwa 70 % der Treibhausgasemissionen und sind daher wichtige Akteure im Klimaschutz bzw. eine wichtige Zielgruppe von Klimapolitiken. Gleichzeitig sind Städte besonders stark von möglichen Auswirkungen des Klimawandels betroffen: Insbesondere extreme Wetterereignisse wie Hitzewellen oder Starkregenereignisse mit Überflutungen verursachen in Städten hohe Sachschäden und wirken sich negativ auf die Gesundheit der städtischen Bevölkerung aus. Daher verfolgt das Projekt ExTrass das Ziel, die städtische Resilienz gegenüber extremen Wetterereignissen in enger Zusammenarbeit mit Stadtverwaltungen, Strukturen des Bevölkerungsschutzes und der Zivilgesellschaft zu stärken. Im Fokus stehen dabei (kreisfreie) Groß- und Mittelstädte mit 50.000 bis 500.000 Einwohnern, insbesondere die Fallstudienstädte Potsdam, Remscheid und Würzburg. Der vorliegende Bericht beinhaltet die Ergebnisse der 14-monatigen Definitionsphase von ExTrass, in der vor allem die Abstimmung eines Arbeitsprogramms im Mittelpunkt stand, das in einem nachfolgenden dreijährigen Forschungsprojekt (F+E-Phase) gemeinsam von Wissenschaft und Praxispartnern umgesetzt werden soll. Begleitend wurde eine Bestandsaufnahme von Klimaanpassungs- und Klimaschutzstrategien/-plänen in 99 deutschen Groß- und Mittelstädten vorgenommen. Zudem wurden für Potsdam und Würzburg Pfadanalysen für die Klimapolitik durchgeführt. Darin wird insbesondere die Bedeutung von Schlüsselakteuren deutlich. Weiterhin wurden im Rahmen von Stakeholder-Workshops Anpassungsherausforderungen und aktuelle Handlungsbedarfe in den Fallstudienstädten identifiziert und Lösungsansätze erarbeitet, die in der F+E-Phase entwickelt und getestet werden sollen. Neben Maßnahmen auf gesamtstädtischer Ebene und auf Stadtteilebene wurden Maßnahmen angestrebt, die die Risikowahrnehmung, Vorsorge und Selbsthilfefähigkeit von Unternehmen und Bevölkerung stärken können. Daher wurde der Stand der Risikokommunikation in Deutschland für das Projekt aufgearbeitet und eine erste Evaluation von Risikokommunikationswerkzeugen durchgeführt. Der Bericht endet mit einer Kurzfassung des Arbeitsprogramms 2018-2021. N2 - Cities are responsible for around 70 % of the global greenhouse gas emissions and are hence important for climate mitigation; consequently they are a crucial target group of climate policies. At the same time, cities are also severely affected by potential impacts of climate change: extreme weather events such as heat waves or heavy precipitation (pluvial floods) cause high economic losses in urban areas and have adverse effects on the health of the urban population. Therefore, the project ExTrass is aimed at measurably enhancing cities’ resilience against extreme weather events jointly with representatives of urban administrations, disaster assistance and civil society. The project focusses on small metropolises and medium-sized cities with 50,000 to 500,000 inhabitants, in particular on the case study cities of Potsdam, Remscheid and Würzburg. The report summarizes the results of a 14-month definition phase whose main purpose was to define the research program of the successive 3-year-R+D-project, to be implemented jointly by researchers and practitioners. In addition, an inventory of climate change adaptation and climate mitigation strategies and plans of 99 German metropolises and medium-sized cities was created. Moreover, an in-depth analysis of the pathways of climate policies in the cities of Potsdam and Würzburg was conducted, which particularly revealed the relevance of key personalities. Furthermore, current challenges in climate adaptation and needs for action were identified during stakeholder workshops in the case study cities. In addition, possible solutions were discussed which will be implemented and tested during the R+D-project. Besides measures on the city level and on the level of urban districts, options that improve risk awareness, preparedness and coping capacities of enterprises and residents are strived for. Thus the state-of-the-art of risk communication in Germany was reviewed for the project and a first evaluation of a serious game was performed. The report ends with a brief outline of the work program 2018-2021. KW - Klimaanpassung KW - Klimaschutz KW - Pfadanalysen KW - Stadtentwicklung KW - Hitze KW - Starkregen KW - Risikokommunikation KW - Potsdam KW - Würzburg KW - Deutschland KW - Climate Adaptation KW - Climate Mitigation KW - analysis of pathways KW - urban development KW - heat KW - pluvial flooding KW - risk communication KW - city of Potsdam KW - city of Wuerzburg KW - Germany Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-416067 ER - TY - JOUR A1 - Riese, Miriam A1 - Thieken, Annegret A1 - Müggenburg, Eva A1 - Bubeck, Philip T1 - Synergies and barriers of the possible integration of heavy rainfall for the implementation of the European Floods Directive JF - Hydrologie und Wasserbewirtschaftung N2 - The heavy rainfall events in recent years have caused great damage, which has increased the public awareness of the topic of heavy rainfall. For this reason, this article discusses how a systematic integration of heavy rainfall within the framework of the European Floods Directive would be possible and reasonable. For this purpose, a matrix covering possible synergies and barriers was created for all steps of the directive, which were then examined in 15 semi-structured interviews with representatives from specialized administration, the private sector and academia. Although there are some synergies, the additional effort required, especially regarding the identification of the risk areas and the higher level of detail required for risk modeling, would be so high that the European Floods Directive cannot be deemed to be an appropriate framework for heavy rainfall risk management. Nevertheless, there is a need for action, e.g. in the field of self-protection, improved risk communication to the population, combined with increased public and interagency cooperation. T2 - Synergien und Hemmnisse einer möglichen Integration von Starkregen in die Bearbeitung der europäischen Hochwasserrisikomanagementrichtlinie KW - Flood KW - heavy rainfall KW - EU Floods Directive KW - Federal Water Act KW - Hochwasser KW - Starkregen KW - Hochwasserrisikomanagementrichtlinie KW - Wasserhaushaltsgesetz Y1 - 2019 U6 - https://doi.org/10.5675/HyWa_2019.4_1 SN - 1439-1783 VL - 63 IS - 4 SP - 193 EP - 202 PB - Bundesanst. für Gewässerkunde CY - Koblenz ER - TY - JOUR A1 - Samprogna Mohor, Guilherme A1 - Hudson, Paul A1 - Thieken, Annegret T1 - A comparison of factors driving flood losses in households affected by different flood types JF - Water resources research N2 - Flood loss data collection and modeling are not standardized, and previous work has indicated that losses from different flood types (e.g., riverine and groundwater) may follow different driving forces. However, different flood types may occur within a single flood event, which is known as a compound flood event. Therefore, we aimed to identify statistical similarities between loss-driving factors across flood types and test whether the corresponding losses should be modeled separately. In this study, we used empirical data from 4,418 respondents from four survey campaigns studying households in Germany that experienced flooding. These surveys sought to investigate several features of the impact process (hazard, socioeconomic, preparedness, and building characteristics, as well as flood type). While the level of most of these features differed across flood type subsamples (e.g., degree of preparedness), they did so in a nonregular pattern. A variable selection process indicates that besides hazard and building characteristics, information on property-level preparedness was also selected as a relevant predictor of the loss ratio. These variables represent information, which is rarely adopted in loss modeling. Models shall be refined with further data collection and other statistical methods. To save costs, data collection efforts should be steered toward the most relevant predictors to enhance data availability and increase the statistical power of results. Understanding that losses from different flood types are driven by different factors is a crucial step toward targeted data collection and model development and will finally clarify conditions that allow us to transfer loss models in space and time.
Key Points
Survey data of flood-affected households show different concurrent flood types, undermining the use of a single-flood-type loss model Thirteen variables addressing flood hazard, the building, and property level preparedness are significant predictors of the building loss ratio Flood type-specific models show varying significance across the predictor variables, indicating a hindrance to model transferability KW - Loss modeling KW - Riverine floods KW - Surface floods KW - Groundwater KW - Levee KW - breaches KW - Compound flood event Y1 - 2020 U6 - https://doi.org/10.1029/2019WR025943 SN - 0043-1397 SN - 1944-7973 VL - 56 IS - 4 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Samprogna Mohor, Guilherme A1 - Thieken, Annegret A1 - Korup, Oliver T1 - Residential flood loss estimated from Bayesian multilevel models JF - Natural Hazards and Earth System Sciences N2 - Models for the predictions of monetary losses from floods mainly blend data deemed to represent a single flood type and region. Moreover, these approaches largely ignore indicators of preparedness and how predictors may vary between regions and events, challenging the transferability of flood loss models. We use a flood loss database of 1812 German flood-affected households to explore how Bayesian multilevel models can estimate normalised flood damage stratified by event, region, or flood process type. Multilevel models acknowledge natural groups in the data and allow each group to learn from others. We obtain posterior estimates that differ between flood types, with credibly varying influences of water depth, contamination, duration, implementation of property-level precautionary measures, insurance, and previous flood experience; these influences overlap across most events or regions, however. We infer that the underlying damaging processes of distinct flood types deserve further attention. Each reported flood loss and affected region involved mixed flood types, likely explaining the uncertainty in the coefficients. Our results emphasise the need to consider flood types as an important step towards applying flood loss models elsewhere. We argue that failing to do so may unduly generalise the model and systematically bias loss estimations from empirical data. KW - damage KW - insurance KW - Germany KW - transferability KW - preparedness KW - recovery Y1 - 2020 U6 - https://doi.org/10.5194/nhess-21-1599-2021 SN - 2195-9269 VL - 21 SP - 1599 EP - 1614 PB - European Geophysical Society CY - Katlenburg-Lindau ER - TY - GEN A1 - Samprogna Mohor, Guilherme A1 - Thieken, Annegret A1 - Korup, Oliver T1 - Residential flood loss estimated from Bayesian multilevel models T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Models for the predictions of monetary losses from floods mainly blend data deemed to represent a single flood type and region. Moreover, these approaches largely ignore indicators of preparedness and how predictors may vary between regions and events, challenging the transferability of flood loss models. We use a flood loss database of 1812 German flood-affected households to explore how Bayesian multilevel models can estimate normalised flood damage stratified by event, region, or flood process type. Multilevel models acknowledge natural groups in the data and allow each group to learn from others. We obtain posterior estimates that differ between flood types, with credibly varying influences of water depth, contamination, duration, implementation of property-level precautionary measures, insurance, and previous flood experience; these influences overlap across most events or regions, however. We infer that the underlying damaging processes of distinct flood types deserve further attention. Each reported flood loss and affected region involved mixed flood types, likely explaining the uncertainty in the coefficients. Our results emphasise the need to consider flood types as an important step towards applying flood loss models elsewhere. We argue that failing to do so may unduly generalise the model and systematically bias loss estimations from empirical data. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1148 KW - damage KW - insurance KW - Germany KW - transferability KW - preparedness KW - recovery Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-517743 SN - 1866-8372 SP - 1599 EP - 1614 ER - TY - JOUR A1 - Wutzler, Bianca A1 - Hudson, Paul A1 - Thieken, Annegret T1 - Adaptation strategies of flood-damaged businesses in Germany JF - Frontiers in water N2 - Flood risk management in Germany follows an integrative approach in which both private households and businesses can make an important contribution to reducing flood damage by implementing property-level adaptation measures. While the flood adaptation behavior of private households has already been widely researched, comparatively less attention has been paid to the adaptation strategies of businesses. However, their ability to cope with flood risk plays an important role in the social and economic development of a flood-prone region. Therefore, using quantitative survey data, this study aims to identify different strategies and adaptation drivers of 557 businesses damaged by a riverine flood in 2013 and 104 businesses damaged by pluvial or flash floods between 2014 and 2017. Our results indicate that a low perceived self-efficacy may be an important factor that can reduce the motivation of businesses to adapt to flood risk. Furthermore, property-owners tended to act more proactively than tenants. In addition, high experience with previous flood events and low perceived response costs could strengthen proactive adaptation behavior. These findings should be considered in business-tailored risk communication. KW - risk management KW - climate change adaptation KW - floods KW - disaster risk KW - reduction KW - Germany KW - precaution KW - emergency management Y1 - 2022 U6 - https://doi.org/10.3389/frwa.2022.932061 SN - 2624-9375 VL - 4 PB - Frontiers Media CY - Lausanne ER - TY - JOUR A1 - Vorogushyn, Sergiy A1 - Apel, Heiko A1 - Kemter, Matthias A1 - Thieken, Annegret T1 - Analyse der Hochwassergefährdung im Ahrtal unter Berücksichtigung historischer Hochwasser T1 - Analysis of flood hazard in the Ahr Valley considering historical floods JF - Hydrologie und Wasserbewirtschaftung N2 - The flood disaster in July 2021 in western Germany calls for a critical discussion on flood hazard assessment, revision of flood hazard maps and communication of extreme flood scenarios. In the presented work, extreme value analysis was carried out for annual maximum peak flow series at the Altenahr gauge on the river Ahr. We compared flood statistics with and without considering historical flood events. An estimate for the return period of the recent flood based on the Generalized Extreme Value (GEV) distribution considering historical floods ranges between about 2600 and above 58700 years (90% confidence interval) with a median of approximately 8600 years, whereas an estimate based on the 74-year long systematically recorded flow series would theoretically exceed 100 million years. Consideration of historical floods dramatically changes the flood quantiles that are used for the generation of official flood hazard maps. The fitting of the GEV to the time series with historical floods reveals, however, that the model potentially inadequately reflects the flood population. In this case, we might face a mixed sample, in which extreme floods result from very different processes compared to smaller floods. Hence, the probabilities of extreme floods could be much larger than those resulting from a single GEV model. The application of a process-based mixed flood distribution should be explored in future work.
The comparison of the official HQextrem flood maps for the AhrValley with the inundation areas from July 2021 shows a striking discrepancy in the affected areas and calls for revision of design values used to define extreme flood scenarios. The hydrodynamic simulations of a 1000-year return period flood considering historical events and of the 1804 flood scenario compare much better to the flooded areas from July 2021, though both scenarios still underestimated the flood extent.
Particular effects such as clogging of bridges and geomorphological changes of the river channel led to considerably larger flooded areas in July 2021 compared to the simulation results. Based on this analysis, we call for a consistent definition of HQextrem for flood hazard mapping in Germany, and suggest using high flood quantiles in the range of a 1,000-year flood. Flood maps should additionally include model-based reconstructions of the largest, reliably documented historical floods and/or synthetic worst-case scenarios. This would be an important step towards protecting potentially affected population and disaster management from surprises due to very rare and extreme flood events in future. N2 - Die Hochwasserkatastrophe im Juli 2021 in Westdeutschland erfordert eine kritische Diskussion über die Abschätzung der Hochwassergefährdung, Aktualisierung von Hochwassergefahrenkarten und Kommunikation von extremen Hochwasserszenarien. In der vorliegenden Arbeit wurde die Extremwertstatistik für die jährlichen maximalen Spitzenabflüsse am Pegel Altenahr im Ahrtal mit und ohne Berücksichtigung historischer Hochwasser berechnet und verglichen. Die Schätzung der Wiederkehrperiode für das aktuelle Hochwasser mittels Generalisierter Extremwertverteilung (GEV) unter Berücksichtigung historischer Hochwasser schwankt zwischen etwa 2.600 und über 58.700 Jahren (90%-Konfidenzintervall) mit einem Median bei etwa 8.600 Jahren, wogegen die Schätzung, die nur auf der systematisch gemessenen Abflusszeitreihe von 74 Jahren basiert, theoretisch eine Wiederkehrperiode von über 100 Millionen Jahren ergeben würde. Die Berücksichtigung der historischen Hochwasser führt zu einer dramatischen Änderung der Hochwasserquan- tile, die für eine Gefahrenkartierung zugrunde gelegt werden. Die Anpassung der GEV an die Zeitreihe mit historischen Hochwassern zeigt dennoch, dass das GEV-Modell möglicherweise die Grundgesamtheit der Hochwasser im Ahrtal nicht adäquat abbilden kann. Es könnte sich im vorliegenden Fall um eine gemischte Stichprobe handeln, in der die extremen Hochwasser im Vergleich zu kleineren Ereignissen durch besondere Prozesse hervorgerufen werden. Somit könnten die Wahrscheinlichkeiten von extremen Hochwassern deutlich größer sein, als aus dem GEV-Modell hervorgeht. Hier sollte in Zukunft die Anwendung einer prozessbasierten Mischverteilung untersucht werden. Der Vergleich von amtlichen Gefahrenkarten zu Extremhochwassern (HQextrem) im Ahrtal mit den Überflutungsflächen vom Juli 2021 zeigt eine deutliche Diskrepanz in den betroffenen Gebieten und die Notwendigkeit, die Grundlagen zur Erstellung der Extremszenarien zu überdenken. Die hydrodynamisch-numerischen Simulationen von 1.000-jährlichen Hochwassern (HQ1000) unter Berücksichtigung historischer Ereignisse und des größten historischen Hochwassers 1804 können die Gefährdung des Juli-Hochwassers 2021 deutlich besser widerspiegeln, wenngleich auch diese beiden Szenarien die Überflutungsflächen unterschätzen. Besondere Effekte wie die Verklausung von Brücken und die geomorphologischen Änderungen im Flussschlauch führten zu noch größeren Überflutungs- flächen im Juli 2021, als die Simulationsergebnisse zeigten. Basierend auf dieser Analyse wird eine einheitliche Festlegung von HQextrem bei Hochwassergefahrenkartierungen in Deutschland vorgeschlagen, die sich an höheren Hochwasserquantilen im Bereich von HQ1000 orientiert. Zusätzlich sollen simulationsbasierte Rekonstruktionen von den größten verlässlich dokumentierten historischen Hochwassern und/oder synthetische Worst-Case-Szenarien in den Hochwassergefahrenkarten gesondert dargestellt werden. Damit wird ein wichtiger Beitrag geleistet, um die potenziell betroffene Bevölkerung und das Katastrophenmanagement vor Überraschungen durch sehr seltene und extreme Hochwasser in Zukunft besser zu schützen. KW - Extreme value statistics KW - historical floods KW - flood hazard mapping; KW - inundation simulation KW - Ahr River KW - Extremwertstatistik KW - historische Hochwasser KW - Gefahrenkarten KW - Überflutungssimulation KW - Ahr Y1 - 2022 U6 - https://doi.org/10.5675/HyWa_2022.5_2 SN - 1439-1783 VL - 66 IS - 5 SP - 244 EP - 254 PB - Bundesanst. für Gewässerkunde CY - Koblenz ER -