NH1.5 | Managing flood and drought risks across borders
Wed, 08:30
EDI PICO
Managing flood and drought risks across borders
Co-organized by HS13
Convener: Tim BuskerECSECS | Co-conveners: Sergiy Vorogushyn, Davide Zoccatelli, Daniela Rodriguez CastroECSECS, Thijs EndendijkECSECS
PICO
| Wed, 30 Apr, 08:30–10:15 (CEST)
 
PICO spot 3
Wed, 08:30

PICO: Wed, 30 Apr | PICO spot 3

PICO presentations are given in a hybrid format supported by a Zoom meeting featuring on-site and virtual presentations. The button to access the Zoom meeting appears just before the time block starts.
Chairpersons: Tim Busker, Daniela Rodriguez Castro, Thijs Endendijk
08:30–08:35
Droughts
08:35–08:37
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PICO3.1
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EGU25-20048
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On-site presentation
Pedram Rowhani, Chloe Hopling, Ahmed Mohamoud, Dominic Kathiya, Gift Mashango, and Maurine Ambani

Using transdisciplinary approaches, PASSAGE brings together a diverse team with the aim of addressing several gaps by co-developing with pastoral communities, local government, and the civil society, inclusive and cross-scale risk narratives and anticipatory action (AA) plans based on predictive multi-hazard impact-based forecasts to effectively build the resilience of pastoral communities. PASSAGE particularly focuses on the transboundary regions within the region as these host the most vulnerable pastoral communities with acute malnutrition levels. 

The current food insecurity over the Greater Horn of Africa region is deeply alarming, with millions among the pastoral communities particularly affected. Whilst this evolving food security crisis has been well monitored and forecasted, the extent of early actions has been demonstrably insufficient to save lives and livelihoods. The goal of PASSAGE, a CLARE-funded project, is to co-produce knowledge for action with all sections of pastoral societies. The project is driven by research questions and activities, which include identifying indicators and triggers that best capture the impacts of drought and extreme temperature on diverse socio-ecological landscapes; estimating the cascading impacts of these hazards on pastoral livelihoods; evaluating the most effective AA to build the resilience of pastoral communities at phased lead times; and defining mechanisms for coordinated transboundary AA plans. The project is at its midway point and we will be sharing some exciting results. 

How to cite: Rowhani, P., Hopling, C., Mohamoud, A., Kathiya, D., Mashango, G., and Ambani, M.: PASSAGE: strengthening PAStoral livelihoodS in the African Greater horn through Effective anticipatory action, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20048, https://doi.org/10.5194/egusphere-egu25-20048, 2025.

08:37–08:39
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PICO3.2
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EGU25-12019
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On-site presentation
Teun Schrieks, Rhoda Odongo, Ileen Streefkerk, Hans de Moel, Tim Busker, Toon Haer, David MacLeod, Katerina Michaelides, Michael Singer, Mohammed Assen, Anne van Loon, and George Otieno

The Horn of Africa drylands (HAD) encompassing Kenya, Somalia, and Ethiopia recently endured an unprecedented multi-year drought from 2020 to 2023, causing devastating impacts. This study investigates these impacts and the dynamics of human adaptation in response to the drought, comparing it to earlier drought events (i.e., 2016-2018) to identify key lessons. First, drought impact data—covering milk production, trekking distances to water sources, and internally displaced persons (IDPs)—are analyzed over time to provide a detailed overview of drought dynamics. Second, household survey data (n=752) are used to examine community perceptions of the drought period and their adaptation strategies. Finally, agent-based modelling (ABM) simulations explore the interactions between mitigation, adaptation decisions, and drought impacts. The results reveal that, on average, the 2020-2023 drought had more severe impacts than the 2016-2018 drought, although the latter exhibited greater variability in impacts. Communities have adopted various adaptation measures to cope with drought effects; however, limited knowledge and financial resources remain significant barriers to scaling these efforts. ABM simulations indicate that enhancing extension services can boost the adoption of adaptation strategies, leading to increased crop and milk production. Additionally, the simulations suggest that water harvesting can mitigate drought impacts upstream, though it may reduce water availability downstream. These findings highlight the critical need for sustained investments in adaptation measures, timely and well-informed decision-making, and region-specific interventions while carefully considering the trade-offs associated with these strategies. 

How to cite: Schrieks, T., Odongo, R., Streefkerk, I., de Moel, H., Busker, T., Haer, T., MacLeod, D., Michaelides, K., Singer, M., Assen, M., van Loon, A., and Otieno, G.: Drought impacts and community adaptation: perspectives on the 2020-2023 drought in East Africa , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12019, https://doi.org/10.5194/egusphere-egu25-12019, 2025.

08:39–08:41
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PICO3.3
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EGU25-18504
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ECS
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On-site presentation
Deborah Dotta Correa, Micha Werner, and Norbert Cremers

More frequent and more severe low flow events under a changing climate pose significant challenges to water management and impact various sectors such as agriculture, water supply, navigation, energy and recreation. Low flow events naturally occur as a result of periods of drought. While the generation and propagation of low flows will depend on basin characteristics, these are also influenced by human actions, which can aggravate or attenuate their intensity and duration. Here, we focus on understanding of the genesis and propagation of low flows in the Meuse Basin, a transboundary basin shared by France, Belgium, Luxembourg, Germany, and the Netherlands. Characteristics of the different sub-basins of the Meuse were analysed using an extensive 40-year observed streamflow dataset collated from multiple providers across the basin (e.g., Rijkswaterstaat, SPW, EauFrance, ELWAS-WEB, Vlaanderen Waterinfo, Waterschap Limburg). The collated dataset is used to identify low flow periods by comparing daily streamflow to a 20% non-exceedance seasonally adjusted threshold. The degree of human influence is then determined by contrasting indices such as low flow duration and deficit volume between a benchmark naturalised time series and the human-influenced time series. The storage capacity of sub-basins is analysed through annual and seasonal baseflow volumes as well as sub-basin recession constants. The study revealed that sub-basins like the Rur, Amblève and Chiers are high baseflow contributors, though significant human influences are found. This contrasts with the Upper Meuse, which has a lower human influence, albeit with a limited baseflow contribution. Aggravation of low flows due to human influences can be linked to agricultural land use and water abstractions in the basin as well as reservoirs though these can either aggravate or attenuate low flows, depending on how these are operated. These findings provide important insights into the genesis of low flows and water storage in the Meuse. This understanding lays the foundation for proposing tailored adaptation measures at the sub-basin level depending on its characteristics that have the potential to increase the overall basin storage potential and optimise water management; including through Nature-Based Solutions, improved reservoir operations and other infrastructural interventions.

How to cite: Dotta Correa, D., Werner, M., and Cremers, N.: Understanding low flow genesis in the International Meuse Basin, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18504, https://doi.org/10.5194/egusphere-egu25-18504, 2025.

08:41–08:43
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PICO3.4
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EGU25-10500
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On-site presentation
Maarten van der Ploeg and Tami de Lange

Title: Masters of the Meuse: Navigating water scarcity in a shared river basin

Overview
Water management in transboundary river basins is one of the most pressing challenges in the face of climate change and competing sectoral demands. Masters of the Meuse is a serious game designed to simulate the complexities of water allocation and governance in the international Meuse River basin, shared by France, Flanders, Wallonia, the Netherlands, and Germany. By assuming the roles of national water managers, players experience firsthand the intricacies of balancing diverse priorities while preventing regional conflicts caused by water scarcity.

Why Participate?
The Meuse River supports nature, agriculture, industry, drinking water, energy production, recreation and cargo shipping. Over 7 million people in the Netherlands and Flanders rely on the Meuse for drinking water, highlighting the river's critical importance. Competing demands, compounded by climate change, increasingly strain the availability and quality of water resources, making effective and transboundary management more urgent. The game provides an interactive platform to explore the complexities of balancing regional priorities, ensuring sustainable water use, and promoting stability. It is especially valuable for policymakers, researchers, and stakeholders in water management.

Objectives
The game aims to:

  • Develop a deeper understanding of transboundary water governance.
  • Provide an immersive experience in managing water scarcity in the context of climate change and to Illustrate the importance of balancing economic, ecological, and societal priorities.
  • Stimulate the international dialogue on how to manage water resources equitably and sustainably and foster collaboration and negotiation skills for conflict prevention.

Gameplay and Insights
Participants represent countries in the Meuse River Basin, each with distinct water needs. The game unfolds over five rounds, each presenting key decisions:

  • Water allocation: Distribute limited resources across sectors and river systems.
  • Negotiation: Collaborate with neighbouring countries to address cross-border challenges and prevent conflict.
  • Event and climate impacts: Respond to disruptions like extreme weather or droughts.
  • Conflict management: A shared Conflict Tracker monitors tensions. If one country’s demand exceeds supply, the entire region faces a collective loss.

 

 

Success in the game hinges on finding innovative and collaborative solutions that balance national interests with the shared goal of regional stability. This experience simulates the real-world challenges of managing shared water resources in an unpredictable climate.

Relevance to EGU 2025
Masters of the Meuse offers a unique opportunity for researchers, policymakers, and educators to explore the intersection of science, policy, and society. It highlights how hydroclimatic factors, governance frameworks, and negotiation dynamics interact in shared water systems.

Impact
The Meuse River represents the broader challenge of managing shared natural resources globally. By engaging with these issues, participants gain valuable insights into collaborative decision-making and sustainable water use practices.

Join Us
Discover how Masters of the Meuse translates scientific challenges into actionable insights and equips participants with the tools to address the complexities of transboundary water governance. Join us on-site at EGU 2025 in Vienna to experience the game and participate in discussions on its potential applications for research, education, and policymaking.

Together, let’s master the challenges of the Meuse and beyond!

How to cite: van der Ploeg, M. and de Lange, T.: Masters of the Meuse: Navigating water scarcity in a shared river basin , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10500, https://doi.org/10.5194/egusphere-egu25-10500, 2025.

08:43–08:45
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PICO3.5
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EGU25-6162
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On-site presentation
Ting Yu Lin, Ming Hsu Li, and Chuan Bin Jian

    The Taoyuan Tableland has faced a significant shortage of water resources due to booming socio-economic development in the past decades. The Shihmen Reservoir built in 1964 has been gradually unable to support the Taoyuan Tableland's agricultural and public water demands. By analyzing 1995-2014 rainfall data with the 3-month Standardized Precipitation Index (SPI-III), seven extreme meteorology drought events with the SPI-III less than -2 were found. Using the 0.05° statistically downscaled daily rainfall data provided by the Taiwan Climate Change Projection and Information Platform Project (TCCIP), it is expected to have 40 extreme meteorology drought events in 2041-2060. More drought events in the changing climate will further worsen the water shortage. It is urgent to develop adaptation measures for water resources management to enhance the climatic resilience of the Taoyuan Tableland. Agricultural ponds have been used for temporary water storage to support irrigation for more than 70 years, even earlier than the construction of the Shihmen Reservoir. Deepening agricultural ponds to provide distributed water storage capacity over the tableland is considered one of the effective adaptation measures to reduce the impacts of drought. This study focuses on how to systematically integrate and enhance the capacities of agricultural ponds to achieve a better climate-resilient Taoyuan Tableland.

    Components of the Taoyuan Tableland’s water supply-demand system, including the Shihmen reservoir, agricultural ponds, agricultural districts, and water treatment plants, were integrated to build a water-resource system-dynamic model (WRSDM). Baseline (1995-2014) and SSP5-8.5 projections of 2041-2060 were obtained from the TCCIP. The Taiwan Water Resources Assessment Program to Climate Change (TaiWAP) was used to simulate flow discharges for running the WRSDM. The Deficit Percent Day (DPD) index and the Total Agricultural Deficit (TDAg) index are used to evaluate public and agricultural water shortages, respectively. The availability indicator calculated as the ratio of the average time without water shortage to the summation of average time without water shortage and average time of water shortage is used to represent the mean duration of no water shortage in the water resources system. Compared to the baseline (1995-2014), the average TDAg will increase by 10.25% and the availability indicator of public water will decrease by 21.51% due to more drought events in the mid-future (2041-2060). By deepening agricultural ponds by 2 meters, the availability indicator of public water will increase by 0.42% in the mid-future which is better than the case without applying any adaptation measure and indicates water shortage impacts to the domestic and industry sectors can be reduced. In addition to deepening agricultural ponds, different adaptation measures (e.g., rotated irrigation schedules, dry farming, reclaimed water, etc.) will be assessed to provide an optimized combination for adaptation policy recommendations in our future studies.

How to cite: Lin, T. Y., Li, M. H., and Jian, C. B.: Assessing Climate Change Impact and Water Resources Adaptation Measures of the Taoyuan Tableland in Taiwan, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6162, https://doi.org/10.5194/egusphere-egu25-6162, 2025.

08:45–08:47
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PICO3.6
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EGU25-3949
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ECS
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On-site presentation
Ashesh Rudra Paul and Rajib Maity

Northeast India (NEI) plays a key role in national development and environmental security due to its ecological diversity, socioeconomic significance, and strategic importance. In addition to being highly susceptible to climatic extremes, it's crucial for the region to build resilience against such challenges. The NEI, a region traditionally known for its heavy rainfall during the monsoon months (June–September), has witnessed a significant shift in its climatic patterns. The monsoon season, once characterized by consistent rainfall, has now transformed into a flood-drought cycle occurring within the same year. Intense bursts of rainfall lead to widespread flooding, followed by prolonged dry spells that verge on drought conditions. While NEI's vulnerability to flooding has been extensively studied, its susceptibility to drought remains underexplored, despite its growing relevance in the region. Therefore, this study presents a spatial drought vulnerability mapping framework designed to enhance this resilience in NEI, including Bangladesh (NEIB)—a geographically and climatologically intertwined region encompassing diverse landscapes from mountains to coastal plains. The study assesses drought vulnerability for the historical period (1981–2014) and projects future vulnerability (2015–2100) under four Shared Socio-Economic Pathways (SSPs), considering different climatic and socio-economic factors. A total of 16 factors like precipitation, temperature, drainage density, land-cover, surface soil-moisture, population density, etc. are used in this integrated framework. These factors fall under four main categories – hydrology, meteorology, socioeconomics, and agriculture, which employ two Multi-Criteria Decision-Making methods: an Analytical Hierarchy Process and a Weighted Aggregate Sum Product Assessment. Out of all the factors, precipitation emerged as the most influential one, followed by potential evapotranspiration and temperature. The spatial drought vulnerability mapping categorizes the NEIB region into five levels of vulnerability: very low, low, moderate, high, and very high. Interestingly, none of the regions in the NEIB fall into the very low or very high vulnerability categories. Regions such as Tripura, Mizoram, West Bengal, and Bangladesh are categorized as highly vulnerable, while Sikkim, Arunachal Pradesh, and Meghalaya demonstrate greater resilience. Future projections indicate a significant shift in vulnerability patterns. Towards the end of the century (2071–2100), under the SSP585 scenario, the area classified as having moderate vulnerability is expected to decrease from ~85% in the historical period (1981–2014) to approximately ~70%, while the proportion of the region categorized as highly vulnerable is anticipated to rise from ~9% to ~25%. Both the methods demonstrated high accuracy and reliability, achieving Area Under the Curve values above 80% based on Receiver Operating Characteristic curves. A sensitivity analysis via the Stillwell Ranking Method indicated comparable performances by criteria suggesting the robustness of the framework that can be applied to other parts of the world. The findings from such a framework will be helpful to promote the need for actions to mitigate future increases in drought severity in susceptible areas, while the resilience of less-impacted regions might be utilized to derive adaptive measures. As challenges from climate continue to evolve, this study provides valuable information for policymakers and stakeholders seeking to increase regional resilience and achieve sustainable development.

How to cite: Rudra Paul, A. and Maity, R.: Spatial Drought Vulnerability Mapping for Regional Climate Resilience: A study over India’s Northeast including Bangladesh, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3949, https://doi.org/10.5194/egusphere-egu25-3949, 2025.

08:47–08:49
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PICO3.7
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EGU25-17200
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ECS
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On-site presentation
Edward Sparkes, Davide Cotti, Ananya Ramesh, Saskia Werners, and Michael Hagenlocher

To tackle systemic drought risks, both short-term and long-term decision making that anticipates climate change and balances the varying needs and availability of water across different sectors is required. Adaptation pathways are a promising approach which can enable this, by indicating how to implement adaptation options progressively depending on how drought risks emerge under different hydrological and societal conditions. However, for adaptation pathways to be effective for managing systemic drought risks, they need to take into consideration cross-sectoral and cross-border effects, and therefore be informed by risk assessments that identify vulnerabilities and underlying risk drivers across multiple sectors. In this presentation we showcase research from the recently published World Drought Atlas, demonstrating how conceptual models of drought risks can integrate with a pathways approach to manage shared impacts and drivers of drought risks across different sectors.

Individual Drought Impact Chains derived from literature were developed for five impacted systems at the global level (water supply, agriculture, hydropower, inland navigation and ecosystems). These were brought together to create a systemic conceptual model that identified cross-sectoral and cross-border impacts and shared underlying drivers and root causes of drought risks across systems. We then showed how different risk management and adaptation measures, which are often designed for a single system, can have positive effects across different, interconnected systems by tackling these shared risk drivers and root causes. The chosen measures covered diverse sectoral needs, focusing on water resource management, land-use management and governance aspects, and included grey infrastructure, early warning systems, Nature-based Solutions and community-based approaches. Finally, the measures were brought together in a pathways approach, demonstrating how different clusters of measures, when implemented progressively and in consideration of one another, can strengthen co-benefits and create synergies across systems. The pathways show how combing measures can be more effective against increasing levels of risk, and also when measures cease to be effective and a shift to a new pathway is needed. The pathways framework additionally supports the timing of when measures should be considered for implementation, avoiding less desirable adaptation decisions until absolutely necessary.

While this methodology was developed in the context of managing systemic and cross-border drought risks, the measures and pathways also have high relevance for flood management. This signals that such an approach cold equally be developed for systemic flood risks, or for managing hydrological extremes from both floods and droughts. By integrating adaptation pathways with a cross-sectoral conceptual model of risks, dynamic adaptation planning is supported that connects the vulnerabilities of multiple systems with prospective, forward looking risk management. This helps to reduce uncertainty and manage trade-offs in decision making. Such an approach shows the benefits of taking a systemic lens towards the management of drought risks.

How to cite: Sparkes, E., Cotti, D., Ramesh, A., Werners, S., and Hagenlocher, M.: Integrating conceptual risk models with an adaptation pathways approach to assess and manage systemic drought risks across sectors and boarders, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17200, https://doi.org/10.5194/egusphere-egu25-17200, 2025.

Floods
08:49–08:51
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PICO3.8
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EGU25-15747
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ECS
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On-site presentation
Heather J. Murdock, Daniela Rodriguez Castro, Benjamin Dewals, Anna Heidenreich, and Annegret H. Thieken

In July 2021 an intense and rapid onset rainfall event resulted in severe flooding in Belgium as well as neighbouring countries of Germany, the Netherlands, and Luxembourg. The region of Wallonia in Belgium was severely affected with the Vesdre River valley in the province of Liège being particularly hard-hit, with 39 reported fatalities there. The warning system was significantly criticised in the aftermath of the event. Hence, this work addresses the flood forecasting warning and response system (FFWRS) performance in Belgium for the July 2021 flood with a focus on Wallonia. The analysis is based on an online survey (n=550) and addresses the reception of official warnings, interpretation and trust in the warnings, and response behaviour. We investigate which variables may influence behaviour and situational factors which leads to people receiving an official warning in time before the flood including flood severity experienced and risk perception. We find that among the respondents in Wallonia 33% reported that they had not been warned and while 28% were warned through official channels, many did not know how to respond. From a similar survey conducted in Germany we see comparable results, suggesting that there were similar cross border challenges. A first regression analysis of the Belgian data suggests that respondents whose household was highly affected were less likely to receive an official warning in time which is consistent with testimonies reporting that inhabitants in severely affected areas were particularly surprised by the flood. We also investigate the role of risk perception and flood warning. This points to some of the challenges with effectively early warning for flash floods. Our analysis highlights the need to improve Belgium's flood warning system by ensuring timely issuance of warnings and enhanced public understanding. In addition, with a comparison of results to the Germany data we discuss common challenges but also important differences.

How to cite: Murdock, H. J., Rodriguez Castro, D., Dewals, B., Heidenreich, A., and Thieken, A. H.: Learning from the past to inform flood risk management: Analysis of public survey data in Belgium on flood early warning and response during the July 2021 flood, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15747, https://doi.org/10.5194/egusphere-egu25-15747, 2025.

08:51–08:53
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PICO3.9
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EGU25-8837
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On-site presentation
Sergiy Vorogushyn, Elena Macdonald, Bruno Merz, Jeroen Aerts, Benjamin Dewals, Jaap Kwadijk, Kymo Slager, Patrick Willems, and Davide Zoccatelli

Ongoing climate change, resulting in heavier rainfall and potentially higher flood peaks, can challenge flood risk management in many European regions. In particular, flood design values and flood hazard and risk maps can be challenged by future climate conditions. The devastating July 2021 floods in western Europe highlighted the need for transboundary cooperation in adapting flood risk management to climate change. In the JCAR-ATRACE Initiative (Joint Cooperation programme on Applied scientific Research – Accelerate Transboundary Regional Adaptation to Climate Extremes), we review and synthesize how climate change information is integrated into flood risk management in regions of Germany, the Netherlands, Belgium, and Luxembourg. We assess whether regions have published flood policy papers, developed future climate and flood scenarios, and translated these scenarios to flood hazard and risk maps and/or flood design values. Our findings reveal that while all 17 sub-national regions have adaptation plans addressing climate change, only 6 regions have developed future flood projections, with even fewer (3) incorporating climate-adjusted design values and only one providing flood hazard and risk maps under future climate scenarios. Practices vary widely: for example, Flanders in Belgium uses a full range of emission scenarios (CMIP5 RCP2.6 to RCP8.5), while Baden-Württemberg and Bavaria in Germany rely on the high-end scenario (CMIP5 RCP8.5) only. The Netherlands adopts a robust approach using 33 CMIP6 global climate models and a dynamic adaptation pathway framework to address uncertainties. Some regions like Saxony in Germany argue that the spread of projections is too large to derive design values and emphasize the need for standardized scenarios and methods. In summary, our synthesis highlights substantial gaps in incorporating climate change projections into flood risk management and significant regional variation in approaches. The synthesis will hopefully contribute to cross-border learning and foster uptake of climate change adaptation in flood risk management in Europe.

How to cite: Vorogushyn, S., Macdonald, E., Merz, B., Aerts, J., Dewals, B., Kwadijk, J., Slager, K., Willems, P., and Zoccatelli, D.: Practices to include assessments of future climate change in flood risk management in Germany and the Benelux countries , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8837, https://doi.org/10.5194/egusphere-egu25-8837, 2025.

08:53–08:55
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PICO3.10
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EGU25-11137
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ECS
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Highlight
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On-site presentation
Veerle Bril, Jens de Bruijn, Hans de Moel, Tarun Sadana, Tim Busker, Wouter Botzen, and Jeroen Aerts

In July 2021 large flooding took place in North-Western Europe. The Geul river, which is shared between the Netherlands, Belgium and Germany, was one of the flooded catchments, with total damages estimated to be €250 million. Since then, there has been a call for additional flood risk reduction measures in the area, including transboundary nature-based solutions in upstream parts of Belgium and local scale flood-proofing of buildings in The Netherlands.

The main novelty of our study is to make an economic trade-off between upstream nature-based solutions (NBS) and downstream building-level measures. For this, we further develop GEB, a coupled agent-based hydrological model and integrate the hydrodynamic model SFINCS into GEB. Furthermore, to calculate high-resolution risk estimates for buildings, we use object-based exposure data from OpenStreetMap and empirically derived vulnerability curves using survey data at the building level. The model allows us to 1) understand current flood risk in the Geul catchment at the object-level and 2) evaluate the effect of several flood risk reduction measures. The model validation shows good performance against observations of flood extent (CSI=0.66), flood depth, and damage of the July 2021 flood.

We then quantify the risk reduction of several nature-based solutions (wetland restoration, reforestation, retention ponds and the conversion of agricultural land to natural grassland) and building-level adaptation measures (wet-proofing and dry-proofing). Moreover, we examine the effect of upstream nature-based solutions on downstream communities. Finally, we perform a cost-benefit analysis (CBA) to gain insight into which combinations of measures are most desirable. Our results show that NBS are especially effective for less extreme floods with high return periods (<1/25). For extreme floods (>1/25), benefit-cost ratios (BCR) may drop to 0.25 or lower. However, these numbers do not account for co-benefits (e.g. tourism). The results can be used by policymakers to design effective flood risk management strategies.

How to cite: Bril, V., de Bruijn, J., de Moel, H., Sadana, T., Busker, T., Botzen, W., and Aerts, J.: Comparing the effectiveness of upstream nature-based solutions with building-level adaptation measures: a case study for the Geul river, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11137, https://doi.org/10.5194/egusphere-egu25-11137, 2025.

08:55–08:57
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PICO3.11
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EGU25-10808
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On-site presentation
Daniele Ganora, Muhammad Abraiz, Elena Belcore, Giorgio Cannella, Mohamed Housseini Ibrahim, Marco Piras, Francesco Saretto, Maurizio Tiepolo, and Riccardo Vesipa

Much of the food supplied to the city of Niamey (1.5 million inhabitants), the capital of Niger, comes from 150 large commercial horticultural sites and 10 vast irrigated perimeters distributed along the Niger River upstream of the city. These areas are threatened by floods, such as the one that devastated paddy fields and horticultural areas in August 2024. To address this problem, a detailed assessment of the river flood risk, expressed in monetary terms, is urgently needed to complement the early flood warning system.

This activity is part of the SLAPIS Sahel project, which aims to develop a more general framework for flood risk management applied to the transboundary Sirba river basin and the nearby Niger river, with the active participation of the water authorities of Burkina Faso and Niger. In this context, this work focuses on the flood risk analysis of the Niger River upstream of the city of Niamey in a multidisciplinary way. To this aim, a hydrological study of the basin was carried out, taking into account the two types of floods that affect the area: floods due to the local rainy season, and dry season events caused by floods upstream in the Guinea-Conakry basin. A hydraulic model was then used to map the extent of flooding, allowing to study the impact and expected damage to the target areas. Daily satellite imagery was used to assess the extent of recent floods and the characteristics of the exposed areas. All these activities were repeated for both the wet and dry seasons, as agricultural production changes and the impacts are different.

This analysis supports the cost-benefit assessment of possible defense structures.

How to cite: Ganora, D., Abraiz, M., Belcore, E., Cannella, G., Housseini Ibrahim, M., Piras, M., Saretto, F., Tiepolo, M., and Vesipa, R.: Flood risk assessment of agricultural areas along the Niger river upstream Niamey, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10808, https://doi.org/10.5194/egusphere-egu25-10808, 2025.

08:57–08:59
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PICO3.12
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EGU25-15373
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On-site presentation
Mihai Niculita, Tatiana Bunduc, Iurii Bejan, Ioana Chiriac, Elena-Oana Chelariu, Aliona Botnari, Andreea Fedor, and Mihai Ciprian Margarint

In hazard-to-risk assessment, often given the same natural hazard situations, risk is generalized in terms of scenarios and vulnerability. In reality, even in the same natural hazard situations, vulnerability can be different, considering different natural, social, political and economic aspects. This is also the case of the Prut floodplain, which has long been a hard political border and where two different socio-economic regimes have shaped human-environment interactions over the last 55-75 years. Despite the joint construction of the Stânca-Costești reservoir, predominantly downstream the Romanian side built dikes, after the Second World War, resulting in a lower theoretical vulnerability. On the Moldovan side, the dyke network is not very extensive and especially in the floods after 2000, the vulnerability and risks were greater. We mapped the dike network on both banks of the Prut River on LiDAR data and synthesized the post-2000 flood impact to establish a vulnerability estimation framework.

How to cite: Niculita, M., Bunduc, T., Bejan, I., Chiriac, I., Chelariu, E.-O., Botnari, A., Fedor, A., and Margarint, M. C.: Cross-border hydrological hazard and risk differences in the case of the Prut River for Romania and the Republic of Moldova, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15373, https://doi.org/10.5194/egusphere-egu25-15373, 2025.

Multiple hazards
08:59–09:01
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EGU25-14407
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Virtual presentation
Aline Telle and Christian Bréthaut

The Meuse River Basin, like many transboundary river systems, faces a growing number of challenges, exacerbated by climate change, rapid urbanization and population growth. These pressures not only strain water resources, but also increase the frequency and intensity of hydroclimatic extremes such as floods and droughts. In July 2021, floods in Belgium, Luxembourg, the Netherlands, and Germany caused more than 220 deaths and more than 46 billion euros in economic losses. Post-flood assessment reports revealed significant gaps in communication and coordination, especially across borders. The Meuse River Basin is also increasingly affected by droughts, with river discharges below 20 m3/s recorded at Eijsden (Netherlands) in 2018 and 2022. Amid these challenges, there is a heightened focus on alternative solutions to manage these risks, such as detention basins, floodplain restoration, and nature-based approaches, which could significantly affect land use and resource management. The integration of such local measures presents a valuable opportunity, but also demands careful consideration of how different countries within the basin approach land and water governance.

A major barrier to more effective flood and drought management lies in the fragmented nature of data integration and modeling infrastructure. Evaluation reports have pointed to significant communication and coordination gaps, particularly across borders. They found that disparate data sources are often not sufficiently coordinated or shared across the regions that make up the basin, making it difficult to design and implement unified policies. This lack of integration complicates decision-making, creates gaps that hinder the development of cohesive strategies that are essential for managing the basin’s shared resources, increases the likelihood that conflicting measures will be taken in different jurisdictions, undermining the overall resilience of the basin. Although the International Meuse Commission (IMC) acts as platform for exchange and coordination of river basin water management strategies and guarantor of compliance with EU directives like the Water Framework Directive, it lacks the authority and capacity to ensure efficient information exchange among riparian regions. At present, regions and countries turn to bi- or multilateral agreements and projects independently of the IMC. The Netherlands for instance deploys great diplomatic efforts Belgium in an attempt to improve information sharing with Belgium.

This paper examines the relevance and effectiveness of a river basin organization in a basin where regions tend to prefer bilateral agreements and action guided by local implementation visions. It compares the advantages and disadvantages of a governance structure based primarily on bilateral relations with the river basin approach. It reflects on the IMC framework ostensibly regulated by the Water Framework Directive and its failure to add value to effective transboundary river basin cooperation.

Key Words:

Climate change adaptation, international basin cooperation, knowledge co-production, policy integration, transboundary water governance

How to cite: Telle, A. and Bréthaut, C.: Assessing Fragmented Governance and Data Integration Challenges in the Meuse River Basin: A Review of Transboundary Cooperation Effectiveness, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14407, https://doi.org/10.5194/egusphere-egu25-14407, 2025.

09:01–09:03
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PICO3.13
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EGU25-17389
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On-site presentation
Laddaporn Ruangpan, Angela Klein, Christian Albert, Alejandro Dussaillant, Kymo Slager, and Ellis Penning

With global climate change, it is not only getting warmer but precipitation patterns are also shifting. This leads to more intense or prolonged precipitation as well as periods with reduced or no precipitation. Stress testing, a technique originally from engineering, assesses the stability of an object under adverse conditions and has been widely used in the financial sector to evaluate the impact of interacting drivers of change and to plan actions to minimize risks in a standardized and transparent manner.  In the water sector, stress testing has also recently been employed in the Netherlands to map out the vulnerabilities of landscapes and the assets in it to weather extremes. This research aims to advance this stress testing methodology to aid dialogues on improving climate resilience of landscapes. The developed framework serves as a systematic evaluation process designed to assess a system’s behaviour under progressively increasing stress levels linked to a wider variety of hydro-meteorological events. It lists key stressors driving the system and proposes indicators to evaluate performance under stress, including system responses expressed as extend of floods and droughts, shifts in water quality and biodiversity values, and socioeconomic impact. In this research, the methodology is applied by conducting hydrological model experiments to simulate flood and drought scenarios in transboundary catchments. Using a range of stress tests, we explore landscapes’ sensitivity to variations in precipitation patterns and initial conditions. Additionally, the study evaluates potential sponge measures designed to mitigate system stress and enhance its resilience before critical failures occur. By testing these measures, the study assesses their capacity to reduce system pressure, improve adaptability, and enhance resilience to extreme events to limit critical failure or significant operational disruptions.

How to cite: Ruangpan, L., Klein, A., Albert, C., Dussaillant, A., Slager, K., and Penning, E.: Stress testing landscapes’ response to climatic extremes with and without sponge measures, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17389, https://doi.org/10.5194/egusphere-egu25-17389, 2025.

09:03–10:15