• Energy Research

La gestion des risques a réduit la vulnérabilité aux inondations et aux sécheresses dans le monde1,2, mais leurs impacts continuent d'augmenter3. Une meilleure compréhension des causes de l'évolution des impacts est donc nécessaire, mais a été entravée par un manque de données empiriques4,5. Sur la base d'un ensemble de données mondiales de 45 paires d'événements qui se sont produits dans la même zone, nous montrons que la gestion des risques réduit généralement les impacts des inondations et des sécheresses, mais fait face à des difficultés pour réduire les impacts d'événements sans précédent d'une ampleur jamais connue auparavant. Si le deuxième événement était beaucoup plus dangereux que le premier, son impact était presque toujours plus élevé. En effet, la gestion n'a pas été conçue pour faire face à de tels événements extrêmes : par exemple, ils ont dépassé les niveaux de conception des digues et des réservoirs. Dans deux cas de réussite, l'impact du deuxième événement, plus dangereux, a été plus faible, en raison de l'amélioration de la gouvernance de la gestion des risques et des investissements élevés dans la gestion intégrée. La difficulté observée à gérer des événements sans précédent est alarmante, étant donné que des événements hydrologiques plus extrêmes sont projetés en raison du changement climatique3. La gestión de riesgos ha reducido la vulnerabilidad a las inundaciones y sequías a nivel mundial1,2, pero sus impactos siguen aumentando3. Por lo tanto, se necesita una mejor comprensión de las causas de los impactos cambiantes, pero se ha visto obstaculizada por la falta de datos empíricos4,5. Sobre la base de un conjunto de datos global de 45 pares de eventos que ocurrieron dentro de la misma área, mostramos que la gestión de riesgos generalmente reduce los impactos de inundaciones y sequías, pero enfrenta dificultades para reducir los impactos de eventos sin precedentes de una magnitud no experimentada anteriormente. Si el segundo evento era mucho más peligroso que el primero, su impacto era casi siempre mayor. Esto se debe a que la gestión no fue diseñada para hacer frente a tales eventos extremos: por ejemplo, superaron los niveles de diseño de diques y embalses. En dos casos de éxito, el impacto del segundo evento, más peligroso, fue menor, como resultado de una mejor gobernanza de la gestión de riesgos y una alta inversión en la gestión integrada. La dificultad observada para gestionar eventos sin precedentes es alarmante, dado que se proyectan eventos hidrológicos más extremos debido al cambio climático3. Risk management has reduced vulnerability to floods and droughts globally1,2, yet their impacts are still increasing3. An improved understanding of the causes of changing impacts is therefore needed, but has been hampered by a lack of empirical data4,5. On the basis of a global dataset of 45 pairs of events that occurred within the same area, we show that risk management generally reduces the impacts of floods and droughts but faces difficulties in reducing the impacts of unprecedented events of a magnitude not previously experienced. If the second event was much more hazardous than the first, its impact was almost always higher. This is because management was not designed to deal with such extreme events: for example, they exceeded the design levels of levees and reservoirs. In two success stories, the impact of the second, more hazardous, event was lower, as a result of improved risk management governance and high investment in integrated management. The observed difficulty of managing unprecedented events is alarming, given that more extreme hydrological events are projected owing to climate change3. أدت إدارة المخاطر إلى تقليل التعرض للفيضانات والجفاف على مستوى العالم1,2، ومع ذلك لا تزال آثارها تتزايد3. لذلك هناك حاجة إلى فهم أفضل لأسباب تغير التأثيرات، ولكن أعيق ذلك بسبب نقص البيانات التجريبية4، 5. على أساس مجموعة بيانات عالمية مكونة من 45 زوجًا من الأحداث التي وقعت داخل نفس المنطقة، نظهر أن إدارة المخاطر تقلل عمومًا من آثار الفيضانات والجفاف ولكنها تواجه صعوبات في الحد من آثار الأحداث غير المسبوقة ذات الحجم الذي لم تشهده من قبل. إذا كان الحدث الثاني أكثر خطورة من الأول، فإن تأثيره كان دائمًا أعلى. وذلك لأن الإدارة لم تكن مصممة للتعامل مع مثل هذه الأحداث المتطرفة: على سبيل المثال، تجاوزت مستويات تصميم السدود والخزانات. في قصتي نجاح، كان تأثير الحدث الثاني، الأكثر خطورة، أقل، نتيجة لتحسين حوكمة إدارة المخاطر والاستثمار العالي في الإدارة المتكاملة. إن الصعوبة الملحوظة في إدارة الأحداث غير المسبوقة تنذر بالخطر، بالنظر إلى أنه من المتوقع حدوث المزيد من الأحداث الهيدرولوجية المتطرفة بسبب تغير المناخ3.

Changes in land use and climate have a large influence on groundwater recharge and levels. In The Netherlands, precipitation shifts from summer to winter are expected, combined with an increase in summer temperature leading to higher evaporation. These changes in climate could threaten the fresh water supply and increase the importance of large groundwater reservoirs. Sustainable management of these groundwater reservoirs, therefore, is crucial. Changes in land use could help mitigate the effects of climate change by decreasing the evaporation. In this study, we investigate the effect of changes in climate and land use on a large groundwater reservoir in The Netherlands, the Veluwe, for a historical period (1850–2016) and in the future (2036–2065). During the historical period, evaporation increased due to conversions from heather and drift sand to pine forest across the Veluwe. This change in land use had a larger effect on the groundwater recharge than change in climate over the historical period. In the future, an increase in winter precipitation will lead to higher groundwater levels in the elevated parts of the region. Surrounding areas are more vulnerable to an increase in dry periods in the summer. Groundwater reservoirs provide an opportunity to store water during wetter periods, which could alleviate drought impacts in surrounding regions during dry periods. Land use change, such as conversion from pine forest to other land use types, is a possible measure to increase water availability.

Abstract. As the adverse impacts of hydrological extremes increase in many regions of the world, a better understanding of the drivers of changes in risk and impacts is essential for effective flood and drought risk management and climate adaptation. However, there is currently a lack of comprehensive, empirical data about the processes, interactions and feedbacks in complex human-water systems leading to flood and drought impacts. Here we present a benchmark dataset containing socio-hydrological data of paired events, i.e., two floods or two droughts that occurred in the same area. The 45 coupled events occurred in 42 different study areas and cover a wide range of socio-economic and hydro-climatic conditions. The dataset is unique in covering both floods and droughts, in the number of cases assessed, and in the quantity of socio-hydrological data. The benchmark dataset inclues: 1) detailed review style reports about the events and key processes between the two events of a pair; 2) the key data table containing variables that assess the indicators which characterise management shortcomings, hazard, exposure, vulnerability and impacts of all events; 3) a table of the indicators-of-change that indicate the differences between the first and second event of a pair. The advantages of the dataset are that it enables comparative analyses across all the coupled events based on the indicators-of-change and allows for detailed context- and location-specific assessments based on the extensive data and reports of the individual study areas. The dataset can be used by the scientific community for exploratory data analytics e.g. focused on causal links between risk management, changes in hazard, exposure and vulnerability and flood or drought impacts. The data can also be used for the development, calibration and validation of socio-hydrological models. The dataset is available to the public through the GFZ Data Services (Kreibich et al. 2023, link for review: https://dataservices.gfz-potsdam.de/panmetaworks/review/923c14519deb04f83815ce108b48dd2581d57b90ce069bec9c948361028b8c85/). Abstract. As the adverse impacts of hydrological extremes increase in many regions of the world, a better understanding of the drivers of changes in risk and impacts is essential for effective flood and drought risk management and climate adaptation. However, there is currently a lack of comprehensive, empirical data about the processes, interactions and feedbacks in complex human-water systems leading to flood and drought impacts. Here we present a benchmark dataset containing socio-hydrological data of paired events, i.e., two floods or two droughts that occurred in the same area. The 45 paired events occurred in 42 different study areas and cover a wide range of socio-economic and hydro-climatic conditions. The dataset is unique in covering both floods and droughts, in the number of cases assessed, and in the quantity of socio-hydrological data. The benchmark dataset comprises: 1) detailed review style reports about the events and key processes between the two events of a pair; 2) the key data table containing variables that assess the indicators which characterise management shortcomings, hazard, exposure, vulnerability and impacts of all events; 3) a table of the indicators-of-change that indicate the differences between the first and second event of a pair. The advantages of the dataset are that it enables comparative analyses across all the paired events based on the indicators-of-change and allows for detailed context- and location-specific assessments based on the extensive data and reports of the individual study areas. The dataset can be used by the scientific community for exploratory data analyses e.g. focused on causal links between risk management, changes in hazard, exposure and vulnerability and flood or drought impacts. The data can also be used for the development, calibration and validation of socio-hydrological models. The dataset is available to the public through the GFZ Data Services (Kreibich et al. 2023, link for review: https://dataservices.gfz-potsdam.de/panmetaworks/review/923c14519deb04f83815ce108b48dd2581d57b90ce069bec9c948361028b8c85/). Abstract. As the adverse impacts of hydrological extremes increase in many regions of the world, a better understanding of the drivers of changes in risk and impacts is essential for effective flood and drought risk management and climate adaptation. However, there is currently a lack of comprehensive, empirical data about the processes, interactions and feedbacks in complex human-water systems leading to flood and drought impacts. Here we present a benchmark dataset containing socio-hydrological data of paired events, i.e., two floods or two droughts that occurred in the same area. The 45 paired events occurred in 42 different study areas and cover a wide range of socio-economic and hydro-climatic conditions. The dataset is unique in covering both floods and droughts, in the number of cases assessed, and in the quantity of socio-hydrological data. The benchmark dataset includes: 1) detailed review style reports about the events and key processes between the two events of a pair; 2) the key data table containing variables that assess the indicators which characterise management shortcomings, hazard, exposure, vulnerability and impacts of all events; 3) a table of the indicators-of-change that indicates the differences between the first and second events of a pair. The advantages of the dataset are that it enables comparative analyses across all the paird events based on the indicators-of-change and allows for detailed context- and location-specific assessments based on the extensive data and reports of the individual study areas. The dataset can be used by the scientific community for exploratory data analyses e.g. focused on causal links between risk management, changes in hazard, exposure and vulnerability and flood or drought impacts. The data can also be used for the development, calibration and validation of socio-hydrological models. The dataset is available to the public through the GFZ Data Services (Kreibich et al. 2023, link for review: https://dataservices.gfz-potsdam.de/panmetaworks/review/923c14519deb04f83815ce108b48dd2581d57b90ce069bec9c948361028b8c85/). الخلاصة: مع زيادة الآثار السلبية للظواهر الهيدرولوجية المتطرفة في العديد من مناطق العالم، يعد الفهم الأفضل لدوافع التغيرات في المخاطر والآثار أمرًا ضروريًا للإدارة الفعالة لمخاطر الفيضانات والجفاف والتكيف مع المناخ. ومع ذلك، هناك حاليًا نقص في البيانات التجريبية الشاملة حول العمليات والتفاعلات والتغذية المرتدة في أنظمة المياه البشرية المعقدة التي تؤدي إلى آثار الفيضانات والجفاف. نقدم هنا مجموعة بيانات مرجعية تحتوي على بيانات اجتماعية هيدرولوجية للأحداث المزدوجة، أي فيضانان أو موجتي جفاف وقعتا في نفس المنطقة. وقعت الأحداث الـ 45 المزدوجة في 42 منطقة دراسة مختلفة وتغطي مجموعة واسعة من الظروف الاجتماعية والاقتصادية والمائية المناخية. مجموعة البيانات فريدة من نوعها في تغطية كل من الفيضانات والجفاف، وفي عدد الحالات التي تم تقييمها، وفي كمية البيانات الاجتماعية الهيدرولوجية. تتضمن مجموعة البيانات المعيارية ما يلي: 1) تقارير أسلوب المراجعة التفصيلية حول الأحداث والعمليات الرئيسية بين حدثين للزوج؛ 2) جدول البيانات الرئيسية الذي يحتوي على متغيرات تقيم المؤشرات التي تميز أوجه القصور في الإدارة والمخاطر والتعرض والضعف وتأثيرات جميع الأحداث؛ 3) جدول مؤشرات التغيير الذي يشير إلى الاختلافات بين الحدثين الأول والثاني للزوج. تتمثل مزايا مجموعة البيانات في أنها تمكن التحليلات المقارنة عبر جميع الأحداث الثنائية بناءً على مؤشرات التغيير وتسمح بإجراء تقييمات مفصلة للسياق والموقع بناءً على البيانات والتقارير الشاملة لمناطق الدراسة الفردية. يمكن للمجتمع العلمي استخدام مجموعة البيانات لتحليل البيانات الاستكشافية، على سبيل المثال التركيز على الروابط السببية بين إدارة المخاطر والتغيرات في المخاطر والتعرض والضعف وآثار الفيضانات أو الجفاف. يمكن أيضًا استخدام البيانات لتطوير النماذج الاجتماعية الهيدرولوجية ومعايرتها والتحقق من صحتها. مجموعة البيانات متاحة للجمهور من خلال خدمات بيانات GFZ (Kreibich et al. 2023، رابط للمراجعة: https://dataservices.gfz-potsdam.de/panmetaworks/review/923c14519deb04f83815ce108b48dd2581d57b90ce069bec9c948361028b8c85/).

As the negative impacts of hydrological extremes increase in large parts of the world, a better understanding of the drivers of change in risk and impacts is essential for effective flood and drought risk management and climate adaptation. However, there is a lack of comprehensive, empirical data about the processes, interactions and feedbacks in complex human-water systems leading to flood and drought impacts. To fill this gap, we present an IAHS Panta Rhei benchmark dataset containing socio-hydrological data of paired events, i.e. two floods or two droughts that occurred in the same area (Kreibich et al. 2017, 2019). The contained 45 paired events occurred in 42 different study areas (in three study areas we have data on two paired events), which cover different socioeconomic and hydroclimatic contexts across all continents. The dataset is unique in covering floods and droughts, in the number of cases assessed and in the amount of qualitative and quantitative socio-hydrological data contained. References to the data sources are provided in 2023-001_Kreibich-et-al_Key_data_table.xlsx where possible. Based on templates, we collected detailed, review-style reports describing the event characteristics and processes in the case study areas, as well as various semi-quantitative data, categorised into management, hazard, exposure, vulnerability and impacts. Sources of the data were classified as follows: scientific study (peer-reviewed paper and PhD thesis), report (by governments, administrations, NGOs, research organisations, projects), own analysis by authors, based on a database (e.g. official statistics, monitoring data such as weather, discharge data, etc.), newspaper article, and expert judgement. The campaign to collect the information and data on paired events started at the EGU General Assembly in April 2019 in Vienna and was continued with talks promoting the paired event data collection at various conferences. Communication with the Panta Rhei community and other flood and drought experts identified through snowballing techniques was important. Thus, data on paired events were provided by professionals with excellent local knowledge of the events and risk management practices.

AbstractRisk management has reduced vulnerability to floods and droughts globally1,2, yet their impacts are still increasing3. An improved understanding of the causes of changing impacts is therefore needed, but has been hampered by a lack of empirical data4,5. On the basis of a global dataset of 45 pairs of events that occurred within the same area, we show that risk management generally reduces the impacts of floods and droughts but faces difficulties in reducing the impacts of unprecedented events of a magnitude not previously experienced. If the second event was much more hazardous than the first, its impact was almost always higher. This is because management was not designed to deal with such extreme events: for example, they exceeded the design levels of levees and reservoirs. In two success stories, the impact of the second, more hazardous, event was lower, as a result of improved risk management governance and high investment in integrated management. The observed difficulty of managing unprecedented events is alarming, given that more extreme hydrological events are projected owing to climate change3.