Relevant topics include but are not limited to:
• Observations of human impacts on, and responses to, hydrological change
• Interactions of communities with local water resources
• Hydrological models that include anthropogenic effects
• Interdisciplinary qualitive and quantitative methods
• Theoretical models to isolate, conceptualize and/or simulate feedbacks in human-water systems
• Critical reflections on inter- and transdisciplinary projects (problem framings, roles, methods, exclusions, suggested interventions)
• Creation of databases describing the hydrology of human-impacted systems
• Data analyses and comparisons of human-water systems around the globe and especially in the global south
• Human interactions with hydrological extremes, i.e. floods, droughts and water scarcity
• The role of gender, age, and cultural background in the impacts of hydrological extremes, risk and risk perception, and during/after crises and emergencies
PICO: Fri, 8 May, 10:45–18:00 | PICO spot 4
China faces chronic water scarcity and strong spatial-temporal mismatches between water availability and demand, with particularly severe stress in North and Northwest China. Rapid urbanisation, industrial restructuring, and expanding irrigated agriculture have intensified competition among domestic, irrigation, manufacturing, and thermal-cooling water uses. These dynamics reflect coupled human-water feedbacks: socio-economic development reshapes withdrawals, while evolving water constraints and hydroclimatic extremes influence exposure, management responses, and future demand trajectories. A key gap is to causally attribute multi-sector water-use changes to socio-economic and hydroclimatic drivers and to anticipate how their co-evolution may reshape water-use hotspots.
We analyse a new 0.1° gridded dataset of monthly sectoral water withdrawals for China (1965-2022), focusing on emerging domestic-use hotspots and their interaction with other sectors as a first step towards diagnosing cross-sector trade-offs and human-water feedback pathways. National annual domestic withdrawals increased from 1.9×1010 to 9.3×1010 m3 (1965-2022). A piecewise linear fit indicates three growth phases and a recent slowdown: moderate growth before 1975, faster growth during 1976-1992, rapid acceleration in 1993-2010 (slope = 2.3×109 m3yr-1), and a weaker, statistically noisy trend in 2011-2022. Despite the volume increase, domestic seasonality remains stable (amplitude ratio = 0.19; JJA share = 27%).
At the grid-cell level, we compute (i) the long-term trend in annual domestic withdrawals (1965-2022), (ii) relative seasonal amplitude, and (iii) mean annual domestic use in 2000-2022. Hotspots are cells exceeding the 75th percentile in all three metrics. They occupy 17.5% of valid land cells yet account for 24.3% of recent domestic withdrawals and 10.9% of the national domestic-use increase over 2000-2022. The correlation between local trends and recent mean use is extremely high (r = 0.99), indicating growth is concentrated where domestic withdrawals are already substantial, typically along rapidly urbanising corridors.
A complementary multi-sector analysis shows total withdrawals rise from 3.7×1011 to 5.4×1011 m3yr-1 across 1965-1989, 1990-2009, and 2010-2022. Irrigation remains dominant (80%, 68%, 64% of mean withdrawals), but its contribution to growth turns negative in 1990-2009, when domestic and thermal-cooling withdrawals explain 85% and 68% of the net increase. Together, these patterns indicate a transition from an irrigation-dominated regime to a more complex urban- and energy-driven water-use system, with domestic hotspots emerging as critical pressure points for water security.
Ongoing work links these patterns with socio-economic indicators and hydroclimatic variables using Neural Granger Causal and PCMCI+ frameworks, and couples them with deep learning prediction under plausible population, urbanisation, and climate trajectories to assess future hotspot shifts and inform adaptive, resilient water management.
How to cite: Hao, W., Yan, D., Cominola, A., and Castelletti, A.: High-resolution Reconstruction and Causal Framing of Multi-sector Water Withdrawals in China: Emerging Domestic Hotspots and Shifts in Coupled Human-water Regimes, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6924, https://doi.org/10.5194/egusphere-egu26-6924, 2026.
Extreme hydrological events, particularly dam-breach flooding, pose a growing challenge to risk governance worldwide. These events are characterized by short warning times, rapid flood-wave propagation, and potentially catastrophic downstream impacts. Their likelihood is rising due to interacting drivers, such as intensifying rainfall under climate change and altered runoff from land-use transitions. Especially in the Global South, these pressures converge with increased social vulnerability, making the human dimension an essential component of risk assessment. This study leverages valuable data from Brazil (2024-2025), where evacuation drills are mandated by national legislation. These exercises constitute one of the few systematic, large-scale efforts to observe human behavior during simulated dam-failure scenarios. As such, they provide rare empirical insights into how different groups interpret warnings, mobilize, and evacuate under realistic training conditions. We analyze behavioral responses from drill participants settled in the Self-Rescue Area (SRA) downstream of the Ibirité water reservoir (MG-Brazil), focusing on their mobilization performance after receiving an alert. Using ordinal logistic regression, we examine how alert responsiveness is influenced by demographic factors (e.g., gender and age), socio-cognitive variables (e.g., risk perception, emergency preparation), and experiential background (e.g., prior exposure to flood events). This approach allowed the identification of those characteristics that most strongly predict rapid or delayed evacuation initialization. The evacuation drills are characterized by low participation rates (2.4 ± 0.3%), which is a typical pattern in the Brazilian context. In consequence, statistical tests were realized using single year data from 2024 (n = 80) and 2025 (n = 65), and a combined dataset for 2024-2025 (n = 145). Demographic factors had no significant influence on mobilization. In contrast, socio-cognitive variables and experimental background shaped significantly protective actions: persons with prior drill experience took consistently longer to begin evacuating (2024: OR = 3.18 (p = 0.062) / 2025: OR = 3.01 (p = 0.057) / 2024-2025: OR = 2.61 (p = 0.015)); participation at drill-preparatory seminars were associated with shorter mobilization times (2025: OR = 0.27 (p = 0.032) / 2024-2025: OR = 0.35 (p = 0.015)); and experiential background influenced evacuation initiation positively (2025: OR = 4.11 (p = 0.039)). These outcomes suggest that evacuation drills alone may lead to a false sense of security and slower alarm responses. Educational measures and experience with real risk cues, on the other hand, can reduce reaction time during warnings. Interpreted through a human-water feedback framework, the results illustrate how behavioral responses can alter the effective consequences of extreme hydrological events. Rapid mobilization reduces the number of flood-harmed individuals, while delayed responses can exacerbate vulnerability even when warning systems operate as designed. This study demonstrates the critical value of evacuation drills as an important empirical resource for understanding human behavior during extreme hydrological events. The Brazilian context offers an important contribution from the Global South, where empirical data on human–flood interactions remain underrepresented in hydrological risk research. It is recommended to continue data collection and combine datasets of different local evacuation drills to improve the model’s performance and stability over time.
How to cite: Krause Camilo, B., Felipe Rocha Silva, A., Cardoso Eleutério, J., G. Gabrich Fonseca, M. T., and Ferreira Rodrigues, A.: Quantifying behavioral responses to dam-breach flooding evacuation drills as a function of demographic factors, socio-cognitive variables, and experiential background., EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-883, https://doi.org/10.5194/egusphere-egu26-883, 2026.
As the largest freshwater lake in China, Poyang Lake (PYL) has undergone significant hydrological alterations in recent decades, particularly a continuous decline in autumn water levels, yet the relative contributions of different drivers remain controversial. This study integrates similarity analysis with a Dragonfly Algorithm (DA) optimized Gated Recurrent Unit (GRU) model, forming a control variable framework that explicitly separates timing and magnitude effects of different drivers, enabling quantitative attribution of the effects of the Three Gorges Reservoir (TGR) regulation and channel morphological changes on PYL water level decline.The similarity analysis indicates a structural shift in the hydrological linkage between the Yangtze River and PYL after 2003, marked by a decoupling of mainstream discharge and lake water levels. Scenario simulations indicate that TGR regulation primarily alters the seasonal discharge regime, advancing post-flood water level recession by weakening the backwater effect. In contrast, channel morphological changes, including riverbed incision and cross-sectional enlargement, emerge as the dominant and more persistent control on water level decline. Quantitative attribution shows that about 77% of PYL’s water level decline since 2003 is attributed to channel morphological changes, while about 23% is associated with TGR regulation. Overall, among two primary driving factors, TGR regulation mainly governs the timing of water level decline, while channel morphological changes control its magnitude.
How to cite: Wang, X.: Quantitative attribution of the drivers of Poyang Lake water level changes based on similarity analysis and the DA–GRU model, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2047, https://doi.org/10.5194/egusphere-egu26-2047, 2026.
Small reservoirs are a rapidly expanding form of water infrastructure across sub-Saharan Africa, supporting irrigation, livestock watering, fishing, aquaculture, and domestic water supply. These systems are locally governed and highly multifunctional. However, they are rarely subject to regular hydrological or water quality monitoring due to their small size and large numbers. Earth observation (EO) provides a unique opportunity to complement ground data for systematic reservoir assessment across space and time. A previous EO-based study using a Sentinel-2 time series (2018–2024) identified 3,079 small reservoirs in northern Ghana with widespread vulnerability to seasonal drying1. Understanding when and why reservoirs become functionally constrained requires an integrated perspective with information on water availability, but also on water quality and patterns of use, which motivates this research.
In a first step, measurements of turbidity, reflecting light availability as a relevant indicator of water quality, were collected across 103 small reservoirs in northern Ghana in December 2025. These data were analyzed together with information from a detailed reservoir user survey conducted by the International Water Management Institute (IWMI), and vulnerability to drying1. Hierarchical cluster analysis showed three distinct types: 1. Small, moderate vulnerability to drying, high turbidity, mixed irrigation; 2. Large, low vulnerability to drying, low turbidity, fully irrigated; 3. Medium, low vulnerability to drying, moderate turbidity, non-irrigated. Across all reservoirs, turbidity was negatively correlated with reservoir size and positively associated with vulnerability to drying.
In a second step, Sentinel-2-derived turbidity estimates using the C2RCC processor2 were validated using satellite-in-situ match-ups within a ±5-day window. The analysis focused on the dry season to capture early dry-season sediment accumulation following rainfall and late dry-season conditions shaped by aeolian inputs, while minimizing cloud contamination. The resulting turbidity time series (2017–2025) enabled scaling the analysis across space and time, supporting regional comparisons of quantity-quality-use interactions.
This study demonstrates how integrating in-situ observations and EO-derived indicators can support the understanding of functional water constraints in small reservoirs. By jointly considering feedbacks between water quantity, quality, and use, the approach reveals patterns that are not visible from single-variable assessments. While limitations remain, particularly regarding attribution of observed values to specific drivers or management decisions, the framework provides a scalable basis for interpreting vulnerability and emerging risk in small, human-managed water systems. It thus contributes to improved monitoring strategies for data-scarce environments and offers a foundation for informed, locally relevant water management under climatic and socio-economic pressures.
1Siabi, Ebenezer K.; Akpoti, Komlavi; Zwart, Sander J. 2023. Small reservoirs in the northern regions of Ghana and their vulnerability to drying. Colombo, Sri Lanka: International Water Management Institute (IWMI). CGIAR Initiative on Aquatic Foods. 37p.
2Brockman, C., Doerffer, R., Peters, M., Stelzer, K., Embacher, S., & Ruescas, A. (2016). Evolution of the C2RCC Neural Network For Sentinel 2 and 3 for the Retrieval of Ocean Colour Products in Normal and Extreme Optically Complex Waters. Living Planet Symposium, Prague, Czech Republic.
How to cite: Steinbach, S., Abdulai, R., Abdulai, M. T., Akpoti, K., Graw, V., and Zwart, S.: Integrating In-Situ and Earth Observation Data to Support Understanding of Functional Water Constraints in Small Reservoirs in Ghana, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20557, https://doi.org/10.5194/egusphere-egu26-20557, 2026.
Joint operation of reservoirs can effectively reduce flood loss. However, the traditional reservoir operation model considers downstream flood peak rather than flooding loss, due to the heavy computational burden of hydrodynamic simulation. To addressed this issue, the machine learning-based surrogate model, which can accelerate the hydrodynamic simulation, is used to reduce flooding loss by coupling with the reservoir operation model. The machine learning surrogate model can quickly simulate flooding loss, but leads to the reservoir operation model no longer meeting the Markov property. As a result, dynamic programming (DP) and its improved algorithms are unable to deal with this optimization problem. Thus, DP only generates an initial solution, which can be further refined by the pattern search algorithm to minimize flooding loss. The Centianhe and Shuangpai Reservoirs on Xiaoshui River Basin, Hunan Province, China were selected as the study area. Results showed that: (1) the surrogate model can shorten the flooding loss calculation time from the minute level of the hydrodynamic model to the millisecond level, while ensuring accuracy of average RMSE 0.629 m and the R2 0.83, and (2) the proposed reservoir operation model significantly reduces flooding loss. Compared with traditional models, the proposed model reduces flooding loss by 16.28 % and 13.74 % under the design floods of 3-year and 5-year return period, respectively. Even the proposed method can be improved in terms of model generalizability and accuracy, it provides a valuable model for high flood risk basins by shifting the reservoir operation objective from flood peak shaving to flooding loss reduction.
How to cite: Bao, Y. and Liu, P.: Surrogate model of flooding loss to alleviate computational burden in reservoirs operation, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10664, https://doi.org/10.5194/egusphere-egu26-10664, 2026.
Flood regulation measures (primarily through dams), combined with a range of non-regulative measures, sit at the heart of modern flood management aiming to mitigate flood impacts. However, the undertaken flood protection measure for a particular region is often selected based on how flood risk evolves under historical and future climate scenarios, whereas relatively less attention has been paid to assess the effectiveness and burden of different measures in face of varying flood magnitudes (constrained by hydroclimatic conditions) and protection targets (constrained by human settlements in floodplains). As a result, it remains unclear whether existing dams can realistically meet evolving protection demands, or whether they are already operating under disproportionately increasing pressure.
To address this, we introduce a quantitative framework (FRAMES, Zheng & Lin, 2025) to evaluate the applicability and adaptivity of regulative measures. We focus on how systems bear the Operational Load (OL)—defined as the storage demand placed on infrastructure across varying flood magnitudes (Return Periods) and protection targets (Exposure Levels). By analyzing 4,732 global settlements paired with 5,963 dams, we quantify the response patterns of OL across diverse geographic and developmental settings globally. These settlements are further categorized into distinct archetypes based on the marginal effectiveness of their regulative systems. Preliminary findings indicate that 57.5% of global settlement show diminishing returns of applying dams for flood protection. Such results indicate in these regions, management should prioritize land-use controls, zoning, and local resilience measures to alleviate disproportionate infrastructure pressure. Conversely, in regions where regulative potential remains high, emphasis should be placed on maintaining system redundancy and avoiding infrastructure lock-in. This study provides the first global quantitative baseline of flood protection potentials and adaptivity, offering a new foundation for evidence-based decision-making in flood management.
How to cite: Zheng, K., Lin, P., and Yamazaki, D.: Identifying Global Flood Protection Potential and Archetypes of Dam Regulation by Quantitative Modeling, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18018, https://doi.org/10.5194/egusphere-egu26-18018, 2026.
Hydropower supports India’s renewable energy transition by enhancing grid stability amid growing solar and wind penetration. In the Indian Himalayas, hydropower development and operation occur within ecologically sensitive and geographically complex river systems shaped by political, social, and cultural constraints that influence water management and access to hydrological observations, which often rely on manual or low-frequency gauging. Many river basins are transboundary, and hydrological data sharing is constrained by neighboring riparian states as well as broader geopolitical and security considerations, with high-resolution datasets frequently treated as sensitive. These limitations are further compounded by rivers functioning as socially and spiritually significant landscapes. Within this setting, hydropeaking, characterized by rapid sub-daily adjustments of river discharge to meet electricity generation needs, introduces pronounced flow variations in already stressed river systems. Despite its potential consequences and impacts, empirical evidence on hydropeaking impacts in India remains limited and under-represented. This study presents new field-based evidence from a real-time in-situ monitoring station deployed downstream of a hydropower project in the upper Yamuna basin. The observations reveal highly regular sub-daily water-level fluctuations dominated by rapid up- and down-ramping associated with peaking operations, indicating strong operational control over downstream flow regimes. Sub-daily variations in river water temperature are also observed, pointing to additional complexity in regulated river responses and impacts on the riverine ecosystem. Given the cultural and religious use of rivers such as the Yamuna, these hydrological alterations may further influence human–river interactions. Overall, we highlight the need for fine-scale eco-hydrological monitoring and governance approaches that account for political constraints and socially embedded river use when assessing hydropeaking in Himalayan river systems.
How to cite: Kukreja, A., Chiogna, G., Agarwal, A., and Basilio Hazas, M.: Hydropeaking in the Indian Himalayas: Interactions between Hydropower Operations, River Dynamics, and Societal Governance, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18207, https://doi.org/10.5194/egusphere-egu26-18207, 2026.
The Indo-Gangetic Basin (IGB) is currently a global hotspot for groundwater overexploitation. Over the past two centuries, groundwater levels initially rose due to increased recharge from irrigation canals but later declined as extractions for agricultural, municipal, and industrial use intensified. However, the relative impacts of recharge and abstraction sources, such as precipitation, canal leakage, irrigation return flow, and municipal and industrial use, remain unclear, as do the effects on groundwater-surface water interactions and environmental flows. This study quantifies spatio-temporal changes in groundwater recharge and abstraction over the past two centuries and simulates with a groundwater model the effects on groundwater levels and groundwater-surface water interactions in the Upper Ganga-Yamuna interfluve in Northern India. The findings align with previous studies: canal water infiltration after canal construction (>1830) boosted recharge, but increased abstractions have lowered groundwater levels and reduced river discharge since the 1970s. Today, irrigation accounts for the majority of abstractions, with municipal and industrial uses far smaller. From around 2000, abstraction decreased groundwater levels to such extent that local rivers likely shifted from discharging to infiltrating. Groundwater-surface water interactions have weakened, particularly reducing discharge to local rivers. While the Yamuna and Ganges show reduced groundwater exfiltration, they are not (yet) losing. This shift threatens environmental river flows, degrades surface water quality by limiting wastewater dilution, and harms groundwater quality as polluted river water infiltrates, posing risks to both ecosystems and human health.
How to cite: van Broekhoven, F., Dekker, S., Griffioen, J., Bhagwat, A., and Schot, P.: Groundwater-Surface Water Interaction in the Upper Ganga-Yamuna Interfluve in Northern India: Impact of Two Centuries of Irrigation and Groundwater Use, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4016, https://doi.org/10.5194/egusphere-egu26-4016, 2026.
Effective water governance is critical for steering water scarcity hotspots toward sustainable water use, yet a systematic meta-analysis of water policy effectiveness across such regions is lacking. Here, we assess the effectiveness of water management policies in six major water scarcity hotspots: California, Central Chile, the Ganges–Brahmaputra Basin, the Murray–Darling Basin, Spain, and the U.S. High Plains.
We combine qualitative and quantitative evidence to evaluate policy effectiveness on groundwater levels. First, we reviewed 102 peer-reviewed case studies to compile a database of implemented water management policies and their reported effectiveness. Second, we analysed long-term groundwater level observations using ARX modelling (autoregressive models with exogenous inputs) to remove climate variability. We then applied multiple breakpoint detection methods on the ARX model residuals to identify systematic changes potentially associated with policy interventions.
Across hotspots, the qualitative literature is generally more critical of policy effectiveness than suggested by observed groundwater responses. According to the literature, regulations on groundwater abstraction and the expansion of unconventional water resources are policy categories that are most frequently associated with positive outcomes, while integrated water management approaches are reported as least effective. Consistently, our quantitative analysis most strongly associates groundwater regulation, unconventional water resources, and measures to improve water use efficiency with groundwater stabilization or recovery. The effectiveness of policy categories, however, varies considerably across regions, emphasizing the need for localized and context-specific solutions.
How to cite: Leijnse, M., Bierkens, M., and Wanders, N.: Evaluating the Impact of Water Policies on Groundwater Resources in Major Water Scarcity Hotspots, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5354, https://doi.org/10.5194/egusphere-egu26-5354, 2026.
Flood resilience reflects the capacity to anticipate, withstand, and recover from flood impacts through a combination of available resources and adaptive responses. Despite its prominence in flood risk research, flood resilience is rarely measured empirically in urban environments, where exposure and vulnerabilities evolve dynamically over time. This study examines changes in household-level flood resilience in Ho Chi Minh City (HCMC) between 2020 and 2023 using two longitudinal survey waves (1,000 and 750 households, respectively, including a panel of 560 households that participated in both surveys). Our goal is to identify trends and dynamics of different resilience dimensions over time, along with the drivers of persistent vulnerability. We develop a multi-stage data-driven approach that combines indicator screening, dimension construction, and statistical modelling. A comprehensive set of survey-based indicators capturing flood characteristics, socioeconomic conditions, behavioural responses, and flood damage are first formulated to represent human, social, physical, financial, and natural capitals (5C). Tree-based models are then applied to identify the feature importance associated to the factors most strongly related with changes in flood outcomes. Based on this screening, selected indicators are then aggregated into latent resilience dimensions corresponding to the 5R framework (robustness, redundancy, resourcefulness, rapidity, and recovery). These are combined, producing individual 5R scores and an overall resilience score. The longitudinal design enables comparison of resilience profiles over time and supports the analysis of variation in resilience within Ho Chi Minh. By linking observed household-level capacities to resilience processes, this study supports the empirical measurement of systemic resilience and provides actionable insights for flood risk reduction and adaptation planning in rapidly urbanising flood-prone contexts.
How to cite: Villafani, Y., Hyun, J. H., Cominola, A., and Sairam, N.: Longitudinal assessment of changes in household flood resilience in Ho Chi Minh City, Vietnam, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7523, https://doi.org/10.5194/egusphere-egu26-7523, 2026.
Water availability is fundamentally important to human well-being, economic vitality, and ecosystem health. The United States Geological Survey (USGS) recently completed a comprehensive assessment of water availability in the United States which included water supply, human water consumption, water quality, and ecological flows. The assessment relied upon national-scale models of natural and human processes including hydrologic conditions and human water consumption. Surface water total nitrogen and phosphorus concentrations were assessed along with groundwater nitrate and arsenic concentrations and ecologically relevant streamflow alteration. From 2010–2020, around 27 million people lived in areas where water consumption was > 80 % of water supply and therefore likely to experience regular water limitations. Water limitation was most severe in areas with high withdrawals for crop irrigation. The areal extent of potential water limitation was greatest in 2012–2013 during an unusually hot and dry period and coincided with elevated withdrawals for crop irrigation. Total nitrogen and phosphorus concentrations were elevated in surface water in many parts of the conterminous U.S. (CONUS), particularly agricultural areas. Regional comparisons showed that areas with the most severe water use imbalances also tended to have the highest concentrations of nutrients in surface waters and groundwater contaminants. The analysis highlights the multifaceted ways that excessive human water consumption can create water availability limitations.
How to cite: Stets, E. (., Archer, A., Cashman, M., Martinez, A., Miller, O., and Powlen, K.: Spatial and temporal patterns in water limitations caused by human water use in the conterminous U.S., EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7663, https://doi.org/10.5194/egusphere-egu26-7663, 2026.
Improving drought early warning requires indicators that capture not only precipitation deficits but also how quickly hydrological systems respond and when societal consequences emerge. Here, we assess whether drought propagation pathways and antecedent groundwater conditions in near-natural hydrological systems can serve as early-warning signals for the timing and emergence of drought impacts. We analyze drought propagation in 132 near-natural catchments (areas < 500 km², with no noticeable direct human influence from reservoir storage or abstractions) located within 72 administrative regions in Germany. Using daily precipitation, streamflow, and biweekly groundwater observations spanning almost 70 years, we identify droughts in each hydrological compartment using the variable threshold level method. This allows the reconstruction of event-specific propagation sequences and lag times, which are then linked to Drought Impact Statements (DIS) extracted from news media between 2000 and 2024, documenting the timing and type of reported socio-economic drought impacts. Our results show that drought propagation varies in space and time, with catchments exhibiting different propagation pathways (defined by the order and timing with which drought conditions propagate from precipitation to streamflow and groundwater) and with pathways changing across events. Fully propagated droughts (reaching both streamflow and groundwater) are preceded by prolonged periods of below-average groundwater levels, indicating strong hydrological preconditioning. Linking propagation pathways to reported impacts shows that the timing and composition of socio-economic drought impacts differ across pathways, suggesting that drought propagation through hydrological compartments influence the timing of impact emergence and the sectors affected. Overall, our results highlight how monitoring groundwater levels as indicators of system preconditioning, together with propagation dynamics characterized by short propagation lags, provides impact-relevant information for drought early warning, helping to anticipate impacts.
How to cite: Peña-Guerrero, M. D., Wang, Z., Ebeling, P., Siebert, C., Sodoge, J., de Brito, M. M., Stahl, K., and Tarasova, L.: Fast-responding near-natural hydrological systems as early markers of socio-economic drought impacts, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15942, https://doi.org/10.5194/egusphere-egu26-15942, 2026.
There is mounting evidence of a net transfer of water from land to the sea, causing unprecedented continental drying, now estimated to contribute to global sea level rise besides glacier and ice cap melting. The depletion of aquifers due to overabstraction is a key driver of this trend. Halting continental water depletion and enhancing the recharge of continental storage is imperative and urgent. Reducing water demand through efficiency is key but not enough: we must revert the transfer of water from land to sea. A way to pump back water from sea to land is desalination. Can we regard it as a strategic priority? If so, under which conditions may it be regarded as sustainable from an environmental as well as an economic point of view?
This presentation examines the potential and challenges of seawater desalination as a systemic solution to continental drying. It discusses how desalination and water reuse may support the restoration of the water cycle, enhanced carbon storage in soils and vegetation, and mitigate the impacts of climate change. At the same time it highlights the energy and brine disposal challenges, and the socioeconomic implications standing on the way for desalination to be a full-scale sustainable adaptation and mitigation option.
How to cite: Pistocchi, A.: Can we harness seawater desalination to revert continental drying? , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17791, https://doi.org/10.5194/egusphere-egu26-17791, 2026.
Climate change is increasing the frequency and intensity of hydrological extremes, amplifying both flooding and drought risks. The vulnerability of landscapes to these hydrological disturbances depends on the climate robustness of these systems, which is defined by their resilience, resistance, and recovery potential to disturbances. Climate robustness is driven not only by climate forcing alone, but also through the interactions between hydrological regimes, landscape characteristics, and demographic pressures expressed through land and water use.
In the Netherlands, landscapes are highly engineered, with water levels, land use, and soil conditions controlled to support agriculture and human water consumption. Under current climatic changes, these landscapes are becoming increasingly strained, particularly in sandy areas in the south of the country where population pressures, warming, and drought frequency are intensifying. While national climate and demography scenarios for the future exist, the projected impacts and changes are challenging to translate at local and regional scales that are often more relevant for management.
Here, we present a catchment-scale, indicator-based approach to diagnose climate robustness of the study catchment under current conditions, and explore how directional changes in hydrological drivers and demographic changes may amplify or reduce landscape robustness in the future. We first combined ground water, soil, and land-use spatial indicators in a multi-criteria decision (MCDA) mapping analysis, which identified potentially vulnerable and climate-robust regions within the catchment. Preliminary results show that areas classified as vulnerable are predominantly associated with sandy soils, and agricultural and forested land. These areas also tend to be in close proximity to urban areas, highlighting a potential overlap between hydrologically sensitive landscapes and areas subject to more intensive land use.
In a next phase, we will use a gradient-based modelling approach to stress-test the indicators under plausible directional changes, based on key climatic and demographic pressures projected for the future. Overall, this approach identifies where human–water feedbacks are concentrated spatially, identifies dominant drivers for climate vulnerability, and highlights areas where targeted interventions may be most effective at catchment scales relevant for land and water management.
How to cite: Marcotte, A. L., Weerman, E., van Wijk, D., Teurlincx, S., and Van de Waal, D. B.: Catchment-scale patterns of climate vulnerability in human-impacted landscapes, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17835, https://doi.org/10.5194/egusphere-egu26-17835, 2026.
Water scarcity is a growing concern in many regions worldwide, as demand for clean water increases and supply becomes increasingly uncertain under climate change. Developing socio-economic conditions and growing population increase water demands, while climate change leads to changes in freshwater availability. Water scarcity assessments typically rely on static biophysical measures within discrete time windows, using fixed population and climate change projections, while overlooking demographic dynamics, lifetime evolution, and cumulative deficits across generations.
Here, we calculate monthly water deficits based on sectoral, population-driven demand and water availability worldwide by combining demographic data with an ensemble of global climate and hydrological models from the InterSectoral Impact Model Intercomparison Project (ISIMIP2b). By linking these deficits with gridded population projections and life expectancy, we estimate the proportion of lifetime water demand that remains unmet per individual. Thereby we capture how shifting hydro-climatic and demographic conditions shape water scarcity across generations.
Our analysis shows that younger generations will bear a significantly greater share of lifetime water scarcity. Across all regions, younger generations will face higher lifetime water deficits compared to older generations. Without adaptation, a child born in 2020 is projected to experience 45% of their lifetime water demand unmet. Approximately 706 million children are expected to encounter deficits exceeding half of their lifetime needs—1.5 times more than individuals aged 50–59. This intergenerational disparity is primarily driven by population growth and rising life expectancy in areas with limited adaptive capacity. These findings underscore the urgent need for accelerated adaptation strategies to safeguard water security for future generations.
How to cite: Vanderkelen, I., Davin, É. L., Keune, J., Miralles, D. G., Wada, Y., Müller Schmied, H., Gosling, S., Pokhrel, Y., Satoh, Y., Hanasaki, N., Burek, P., Ostberg, S., Grant, L., Taranu, S., Mengel, M., Volkholz, J., Schleussner, C.-F., and Thiery, W.: Escalating lifetime water deficit for younger generations, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9111, https://doi.org/10.5194/egusphere-egu26-9111, 2026.
Baseflow plays a crucial role in sustaining river aquatic ecosystems, reduced drought impacts necessitating the need to understand how human activities might influence it. Here, we implement a comparative socio-hydrology based approach to identify dominant controls on baseflow reductions across three regions in India irrigated by large reservoirs. We evaluate the effect of conjunctive use of surface water and groundwater on downstream baseflow in areas irrigated by the Nagarjuna Sagar (NSR) in Krishna basin, Hirakud (HRD) in Mahanadi basin and Indira Sagar (ISR) in Narmada basin, three large reservoirs in India. We apply a socio-hydrologic model to simulate surface water and groundwater withdrawals as a function of reservoir inflows, reservoir characteristics, water demands, and aquifer characteristics of the regions. The model constitutes a reservoir module that simulates water releases from the reservoir, a water use module that simulates how farmers use surface water and groundwater to meet irrigation demands, and a conceptual groundwater module to simulate groundwater levels. Farmers extract groundwater when water supplied from reservoirs does not meet irrigation demands. A classification and regression tree (CART) based algorithm was used to quantify the relative influence of different socio-hydrological factors on baseflow reductions due to upstream irrigation. We found an average annual reduction of 323 MCM (1968-2022), 24 MCM (1958-2021) and 13.72 MCM (2005-2022) in baseflow due to the groundwater pumping for NSR, HRD, and ISR, respectively. These translate to 11 %, 5%, and 3% reduction in baseflow compared to a baseline no pumping scenario. Though the relative reduction in baseflow was primarily governed by the volume of groundwater pumped in all cases, accurate characterization of the reduction required information on climate and reservoir characteristics at annual time scales.
How to cite: Jaiswal, V., Singh, R., and Sunkara, S. V.: Comparative socio-hydrology to identify dominant controls on baseflow reductions from human irrigation demands, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17994, https://doi.org/10.5194/egusphere-egu26-17994, 2026.
Human alteration of the nitrogen cycle, through the use of fertilizers and fossil fuels, has intensified the flows of reactive nitrogen to the hydrosphere and degraded the quality of water resources. Imbalanced levels of nitrogen in surface water impact both ecological and human wellbeing, promoting the eutrophication of rivers and lakes and subsequently contributing to losses of wildlife, contaminated drinking water sources, increased health risks and water treatment costs, as well as decreased recreational activities and tourism revenue for local economies.
In order to protect water resources and the communities that rely upon them, approaches capable of understanding the complex interactions between humans and water are needed. System dynamics (SD) is a modelling method that maps, quantifies, and simulates the feedbacks that exist between the causes and consequences of an issue, such as surface water pollution. By capturing the long-term behaviour of non-linear systems and identifying potential leverage points, SD provides a holistic perspective that traditional modelling approaches frequently lack.
In this research, SD is employed to study Missisquoi Bay, a culturally significant waterbody located on the border of Québec, Canada and Vermont, USA, that is experiencing counterintuitive nitrogen trends. Over the last 30 years, levels of nitrogen in Missisquoi Bay have remained stable while loads from the Bay’s tributaries, namely the agriculturally intensive Pike River watershed, have increased, highlighting an existing knowledge gap in the region. Understanding and preventing nitrogen pollution is critical as nitrogen can exacerbate the toxicity of harmful algae blooms, which are already a consistent issue in Missisquoi Bay. Nitrogen loadings are also anticipated to increase in the area with future changes to land use and climate.
A quantitative SD model is being developed for the Pike River-Missisquoi Bay system at a monthly timestep to capture the seasonal variabilities of nitrogen dynamics. The resultant model will be used to evaluate: 1) What biogeochemical or socioeconomic processes are the most influential in governing the levels of nitrogen in the Pike River and Missisquoi Bay; 2) How will these processes change over the period of 2025 – 2050 given different climate, land use, and management scenarios; and 3) What pollution prevention strategies would be most effective in protecting the Bay and its surrounding communities?
Stakeholders and decision makers in the region will be able to use the final SD simulation model as a reliable decision support tool to examine the long-term outcomes of their proposed solutions, select strategies capable of reducing stresses on water quality, and answer “what-if” questions. By disseminating this model, other watersheds in Canada seeking to better understand their nitrogen dynamics will be able to use a consistent framework to improve their policy development and management strategies.
How to cite: Van Heyst, S., Adamowski, J., and Nicolaidis Lindqvist, A.: Understanding Human-Water-Nitrogen Relationships: Using System Dynamics to Study Missisquoi Bay, Québec, Canada, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-768, https://doi.org/10.5194/egusphere-egu26-768, 2026.
Coevolution of coupled human-water systems (CHWS) is critical for long-term sustainable water management, linking to Panta Rhei. However, study of CHWS suffers from complexity brought by diverse natural and social science disciplines. In this study, we investigated the general landscape of the theoretical frameworks, methods and data in CHWS case studies. Our meta-analysis, encompassing 205 cases, draws on eight proposed theoretical frameworks in four typologies, quantifying the prevalence and geographical distribution of methods and data. Results demonstrated the analytical strength of sociohydrology for CHWS, underscoring the need to integrate multidisciplinary theoretical frameworks. Combination of qualitative and quantitative methods and data would help overcoming the limitations of each method when used in isolation, broadening the research scope of disciplines. This requires sociohydrology to enhance its ability of integrating diverse research approaches. The uneven global distribution of CHWS research teams calls for the necessity of increasing collaboration and resource sharing across borders.
How to cite: Lyu, H., Tian, F., Liu, L., Mijic, A., and Wei, J.: Meta-analysis on theoretical framework, method and data for coupled human-water systems: decadal progress and future directions, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8507, https://doi.org/10.5194/egusphere-egu26-8507, 2026.
Mosquito-borne disease Infections are becoming increasingly hazardous in fragile ecological areas. Such areas are characterized by inextricably linked hydrological fluctuations and human activities. Understanding how these processes interact is crucial to understanding the geographical and temporal persistence of arboviral disease risk. We develop a conceptual framework for arboviral transmission within an integrated human-water-environment system, with mosquito ecology acting as the primary biological mediator. The framework is designed based on extensive field visits in Kenya's Rift Valley underpinned by a literature review. Prosopis juliflora is given special attention, as this invasive alien woody plant has significantly altered riparian and floodplain ecosystems in the valley. The framework demonstrates how changes in terrestrial ecosystems and water regimes influence mosquito habitats, vector survival and host interaction, and, ultimately, human health. Prosopis-dominated landscapes could facilitate adult mosquito survival and persistence as well as arboviral transmission under flood and drought conditions. These processes are attributed to enhanced vegetation density, shade, and microclimatic humidity surrounding water bodies. Arboviral transmission persists in landscapes that are rapidly changing due to climate extremes, land degradation, and the spread of invasive alien plant species. The concept also emphasizes bidirectional feedback. It demonstrates how disease burden can exacerbate socioeconomic vulnerability, resource dependency, and ill-oriented practices that promote the spread of invasive species. This framework underscores the importance of an integrated approach for tackling mosquito-borne disease threats in climate-sensitive landscapes that are undergoing fast ecological change.
How to cite: Osman, T., Fevre, E., Junglen, S., and Borgemeister, C.: Human-water-environment feedbacks: A framework for mosquito-borne arboviral diseases in Prosopis juliflora landscapes of Kenya’s Rift Valley, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5905, https://doi.org/10.5194/egusphere-egu26-5905, 2026.
How to cite: Wang, X. and Chen, X.: From Climate-Constrained to Regulation-Dominated: A Shift in Arid Oasis Ecosystem Dynamical State, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12674, https://doi.org/10.5194/egusphere-egu26-12674, 2026.
The paired events dataset that was published by Kreibich et al. (2023), provides a unique dataset on drought and flood risk adaptation between two extreme events across a variety of case studies. This study identifies changes in impacts and attributes them to changes in the different components of risk. It concludes that it remains a challenge to manage unprecedented events (Kreibich et al. 2022). This study and dataset have provided valuable insights in the change in impacts and risk, however, from the dataset it is unclear which underlying socio-hydrological dynamics have led to the variety of changes in risk and impacts across case studies. In this study, we develop a generic model to investigate the socio-hydrological feedbacks between hazard, management, vulnerability and exposure leading to the observed changes in impacts.
We use the model to compare the socio-hydrological processes across the different drought and flood case studies to identify differences in management and adaptation strategies. We show that a generic model, such as the model presented here, in combination with a consistent dataset, such as the paired events dataset, can be useful in comparing socio-hydrological processes across case studies. It can help explore the possibility space in an informed manner, though the identification of current pathways and, following from those current pathways, the identification of suitable adaptation strategies that have been successful in other cases.
How to cite: Barendrecht, M. H., Mazzoleni, M., Van Loon, A. F., and Kreibich, H.: Investigating Socio-Hydrological Feedbacks in Drought and Flood Risk Adaptation: A Comparative Analysis Using the Paired Events Dataset, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10483, https://doi.org/10.5194/egusphere-egu26-10483, 2026.
While amazonian riverine communities have long adapted to seasonally fluctuating water levels, the increasing frequency and severity of the recent hydrological extremes threaten their fragile livelihoods and disrupts the ecosystems on which they depend.
In this study, we investigate socio-hydrological dynamics in the Peruvian Amazonian riverine community of Tamshiyacu by examining how interactions between hydrological extremes, community livelihoods, and public policies shape vulnerability and exposure to drought-flood cycles. Using a system dynamics model, we simulate shifts in livelihoods under varying drought-flood scenarios. Results show that seasonal hydrological anomalies can have both positive and negative effects on this Amazonian riverine community, depending on livelihood type, proximity to major rivers, and local topography. In particular, adaptation strategies that diversify livelihoods strengthen community resilience to hydrological shocks.
These insights underscore the importance of multi-sectoral analyses to better understand how different livelihoods are affected by hydrological anomalies. The results also highlight the need for public policies that promote economic diversification and sustainable resource management to enhance community resilience in the face of increasing climate extremes.
How to cite: Matano, A., Mazzoleni, M., Barendrecht, M. H., Mendoza, H. D., van Loon, A., Valenzuela, J., and Rau, P.: Socio-hydrological dynamics under drought-flood extremes in a Peruvian Amazonian community, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13906, https://doi.org/10.5194/egusphere-egu26-13906, 2026.
Flooding is one of the costliest natural hazards globally and is expected to increase in severity because of climate change and socio-economic developments. Therefore, it is important to implement adaptation measures that limit flood risk. Adaptation measures can be implemented by governments, but also households can flood-proof houses. This is viewed as a promising adaptation strategy, but it is unclear yet how many households will adopt these measures in response to government policies. Therefore, this study aims to understand to what extent various government policies, such as subsidies and information campaigns, can lead to increased implementation of household-level adaptation to reduce risk, such as wet-proofing or dry-proofing. To do so, we further develop a coupled hydrological, hydrodynamic, and agent-based model (GEB). We demonstrate this model for the Geul river in The Netherlands, where a severe flood event took place in July 2021.
The GEB model simulates river discharge over the last 30 years, including the July 2021 flood. When discharge exceeds bankfull conditions, we automatically simulate the flood using the hydrodynamic model SFINCS. Households in flood-prone areas make adaptation decisions on an annual basis, and additionally reconsider their choices following a flood event. This decision-making process is based on the Subjective Expected Utility Theory. Following this theory, flooding elevates the flood risk perception of households and this increased perception triggers adaptation decisions.
Our socio-hydrological simulations show that household adaptation is an effective way to reduce flood damages. Results can be used by policymakers to understand how much flood risk reduction can be achieved through household adaptation and to design strategies to increase adaptation uptake.
How to cite: Bril, V., de Bruijn, J., Busker, T., Botzen, W., Aerts, J., and de Moel, H.: Long-term household flood adaptation under government policies: a coupled hydrological, hydrodynamic, and agent-based model, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12778, https://doi.org/10.5194/egusphere-egu26-12778, 2026.
The Alps play a vital role in regulating water supply for densely populated and agriculturally intensive downstream regions. Yet climate change is raising concerns over the development of water scarcity in mountain areas historically perceived as water abundant. Addressing these challenges requires understanding interdependencies across water uses, i.e., the Water–Energy–Food–Ecosystems (WEFE) Nexus, and untangling the coupled social and hydrological processes that contribute to creating water scarcity. We present a novel methodological framework that integrates Causal Loop Diagrams and the Network of Action Situations to jointly map socio-hydrological dynamics and the multi-level decision-making processes through which rules, institutions and practices influence water use, allocation and management. We apply this framework to the Orco catchment (Northern Italy), which has experienced recurrent summer droughts and water scarcity over the past two decades. Results show that trade-offs across the Nexus arise not only from hydroclimatic variability, but also from socio-economic factors creating levers and barriers to change, and an underlying condition of overallocation of water resources. At the same time, evidence of cross-sectoral synergies is found in both formal instruments (e.g., hydropower concessions and sectoral policies) and through informal, drought-triggered coordination among water users. Two venues of decision-making are central to addressing water scarcity: (i) the governance of hydropower reservoir, which is shifting towards a multipurpose use, and (ii) the implementation of environmental flow requirements, where weak knowledge links between socio-hydrological processes and decision-making create divergences among local actors but also opportunities for collaboration across sectors. By integrating CLD and NAS, our approach maps the cause–effect chains that generate trade-offs among sectoral goals, deepening the understanding of the root causes of water scarcity and providing a basis for more coordinated and resilient governance of water resources in mountain regions.
How to cite: Lucca, E., Sušnik, J., Castelli, G., Piemontese, L., Masia, S., Fantini, E., and Bresci, E.: Socio-hydrology and water-energy-food-ecosystems (WEFE) Nexus approaches to explore water scarcity in an alpine catchment in Northern Italy, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13672, https://doi.org/10.5194/egusphere-egu26-13672, 2026.
Small islands are particularly sensitive to climate change due to limited storage capacity, strong dependence on external energy supplies, and close coupling between human activities and environmental processes. On tourism-dependent islands, fluctuations in population, climate variability, and infrastructure constraints can generate complex feedbacks between human water use, hydrological processes, and ecosystem stress. Green Island, a volcanic island off the southeastern coast of Taiwan, provides a representative case where water-related challenges arise not from a lack of total precipitation, but from the highly episodic nature of rainfall associated with typhoons, during which large volumes of rainwater are rapidly lost through runoff and coastal discharge. This research investigates human–water feedbacks on Green Island by integrating analyses of water balance, energy balance, and climate change impacts within a system-oriented framework, with particular attention to how tourism-driven water and energy demand interacts with hydrological processes under changing climatic conditions and how these interactions may reinforce system vulnerability over time. The water system is conceptualized as a coupled human–natural system, incorporating precipitation inputs, surface and groundwater storage, water treatment and distribution, sectoral water use, and environmental losses such as evapotranspiration and rapid runoff, while human responses to hydrological variability—including infrastructure design and water management practices that limit rainwater retention and reuse—are treated as key drivers shaping feedback dynamics. In parallel, the energy system assessment examines baseline residential demand, seasonal tourism-related electricity use, reliance on diesel-based power generation, and the potential integration of renewable energy sources. Climate change is treated as a cross-cutting driver influencing both hydrological processes and human behavior, as projected increases in rainfall intensity, extreme events, heatwaves, and typhoons are expected to further amplify mismatches between water availability and effective water use. Methodologically, the study integrates hydrological data, energy statistics, climate information, and ecological observations within a conceptual system framework, and employs system dynamics modeling using Vensim at a supporting level to structure causal relationships and explore feedback mechanisms rather than to produce deterministic predictions. By reframing water sustainability as a challenge of retention, reuse, and adaptive management rather than absolute scarcity, this research aims to support more resilient and resource-efficient water governance pathways for small island systems under climate change.
How to cite: Hu, Y.-J. and Tung, C.-P.: Human–Water Feedbacks under Climate Change on a Tourism-Dependent Island: An Integrated Assessment of Water and Energy Balances on Green Island, Taiwan, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12444, https://doi.org/10.5194/egusphere-egu26-12444, 2026.
Climate change is increasingly driving severe and prolonged hydrological droughts—even in humid regions—causing many rivers to shift from perennial to intermittent flow regimes. This trend is especially critical for agricultural watersheds like the Bécancour River basin (Québec, Canada), where expanding cranberry production intensifies water demand during vulnerable low-flow conditions. Addressing these coupled pressures requires capturing the feedback between streamflow and agricultural withdrawals, particularly given the complex reservoir management inherent to cranberry farming. This study presents an integrated socio-hydrological modelling framework to assess the co-evolution of cranberry farm expansion, water availability, and social constraints in the Bécancour River basin. We translate socio-economic survey data from cranberry producers into a System Dynamics (SD) model, capturing key feedback mechanisms related to economic pressure, social license to operate, conflict perception, and future expansion decisions. The SD model is loosely coupled with the distributed hydrological model HYDROTEL through a Python-based wrapper, allowing dynamic exchange between hydrological stress signals and socio-economic decision variables. The coupled framework is applied to explore scenarios, including climate stress, regulatory tightening, conservation-oriented policies, and technological adoption for water-use efficiency. Results highlight how social constraints and adaptive behaviors can significantly modulate hydrological impacts, emphasizing the importance of integrating human decision-making into watershed-scale water management models.
How to cite: Khoramshokooh, N., Rousseau, A. N., and Alizadeh, M. R.: Socio-Hydrological Governance for Watershed-Scale Water Management Accounting for Various Agricultural, Municipal and Industrial Water Uses, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15152, https://doi.org/10.5194/egusphere-egu26-15152, 2026.
Local development in reservoir catchments is often sensitive and contested, as drinking-water protection frequently imposes strict constraints on land use and local livelihoods. This study examines the tea industry in Pinglin, a rural area in northern Taiwan located within the Feitsui Reservoir catchment, to analyze how local economic development has interacted with environmental policy—particularly water resource conservation—and how these interactions have shaped tea landscapes over time. Using a socio-ecological systems (SES) framework, the study employs qualitative methods including literature review, participant observation, in-depth interviews, and public participation geographic information systems (PPGIS). These approaches document landscape and industry change and frame the tea industry as an outcome of interactions between land governance and water governance.
Tea cultivation in Pinglin was introduced during the Qing dynasty, consolidated under Japanese colonial rule, and expanded after World War II, eventually becoming one of Taiwan’s best-known tea-producing regions. Transportation infrastructure emerged as a key driver of this process. Successive mobility corridors—from the Danlan Ancient Trail, to the Beiyi Road, and later an extensive network of industrial roads built between the 1970s and 2000s—connected producers to markets, supported settlement formation, and aligned Pinglin’s tea economy with Taiwan’s broader economic growth. During the 1980s and 1990s, these dynamics transformed a diverse agricultural mosaic of rice paddies, orchards, and tea gardens into landscapes dominated by tea plantations.
This development trajectory shifted with the completion of the Feitsui Reservoir in the 1980s, which supplies drinking water to the Greater Taipei metropolitan area. The designation of a water source protection zone introduced increasingly strict land-use regulation, constraining the expansion and transformation of tea production and raising concerns related to residential land rights and housing justice. A second turning point followed the opening of National Freeway No. 5 in 2000, which reduced Pinglin’s role as a transportation node. Declining visitor numbers, population out-migration, and long-standing demographic aging combined to intensify economic challenges and weaken the social foundations of the tea industry.
Local actors responded through multiple adaptation strategies, including mechanization, organic farming, cooperative production arrangements, and tourism-oriented initiatives. However, many of these efforts were limited by stringent land-use controls that restricted diversification and spatial reconfiguration. At the governance level, limited channels for local political participation further constrained adaptive capacity. Following administrative restructuring in 2010, local representation in this small-population area remained weak, contributing to a governance configuration increasingly oriented toward external and centralized water-resource priorities, with bottleneck effects on local development.
Overall, the Pinglin tea industry emerges not simply as an outcome of environmental conditions, but as a dynamic product of transportation infrastructure, central policy intervention, land-use regulation, and local power relations—most critically, strict land-use control under reservoir water governance. Future work should both examine land-use–water quality relationships and explore environmentally friendly practices and locally applicable water-governance approaches. Strengthening meaningful local participation, through participatory platforms and more representative governance arrangements, may help advance reservoir catchment management that better balances conservation goals with equity and local development needs.
How to cite: Lu, D.-J. and Chen, J.-J.: Water Governance, Land-Use Control, and Local Development in a Reservoir Catchment: The Pinglin Tea Industry, Taiwan, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8015, https://doi.org/10.5194/egusphere-egu26-8015, 2026.
One quarter of the world population lacks safe drinking water. As existing water service providers struggle to make sufficient progress towards the water SDG by 2030, decentralised rural service providers are emerging as possible solutions with pluralist governance arrangements addressing varying water scarcity and quality risks under increasing hydroclimatic extremes, but also financial, operational and social risks. Pooling risks through pluralist arrangements between public, private and community actors with diverse, sometimes competing logics represents both a dilemma and an opportunity for institutional innovation. How pluralist institutions pool risks across different configurations of public, private and community management remains a knowledge gap – theoretically as the relationship between risk and institutional innovation is not fully understood and empirically as the outcomes of such innovations have not been examined systematically. I advance institutional theory of risk, drawing on Douglas’ cultural theory of risk and Ostrom’s approach to institutional diversity. Bridging these theoretical perspectives leads to better understanding how risk-pooling impacts the sustainability of water services, especially under drought conditions. I critically review literature on risk governance in pluralist arrangements and present results from case study research with service providers in Africa, Asia and Europe to identify key institutional design principles of pluralist arrangements. Workshops with service providers and regulators afford insight into the challenges of creating an enabling environment for pluralist organisations and developing comparable standards for monitoring and benchmarking to improve governance. Assessing differences and similarities in risk-pooling strategies and their effect on institutional design thus contributes to informing policy and practice towards safe water for all.
How to cite: Koehler, J.: Risk-pooling and institutional innovation in water service transitions, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21493, https://doi.org/10.5194/egusphere-egu26-21493, 2026.
Hydrological hazards cause significant impacts worldwide. Yet, risk reduction measures (e.g., levees, insurance, and other structural and non-structural interventions) can unintentionally exacerbate the impacts they aim to mitigate. Indeed, when such interventions disregard the complexities of human–water interactions, they can produce adverse outcomes, including the safe development paradox (SDP) and the levee effect (LE), wherein risk-reduction measures paradoxically increase risk by fostering a false safety feeling. Despite growing attention to these socio-hydrological phenomena, empirical evidence remains fragmented.
To consolidate existing knowledge, we reviewed 56 studies published between 2001 and November 2025 that investigated the SDP and LE in specific case studies. Specifically, we analyzed the methodological approaches used, the variables considered, and the extent to which they provided evidence for or against the occurrence of SDP and LE.
Most studies (69.6%) presented conclusive evidence of the SDP or LE through three primary mechanisms: (a) intensified development in protected areas; (b) reduced preparedness and a false safety feeling; and (c) increased damage resulting from rare and extreme events. Only 5.4% of studies reported mitigation or absence of the SDP or LE, highlighting the role of individual preparedness, existing policy frameworks, and risk awareness as potential mitigating factors. Surprisingly, 42.9% of studies focused exclusively on exposure, ignoring vulnerability or behavioral dimensions associated with false safety feeling. This tendency was especially pronounced in the 2024–2025 papers, 68.8% of which considered exposure alone. However, we argue that exposure alone is insufficient to confirm or refute the SDP or LE as it neglects coping capacity, risk perception, and individual adaptation. Consequently, increases in urbanization or population within protected areas cannot, by themselves, confirm the SDP or the LE.
Most studies (44.6%) examined only the effects of structural measures, disregarding the influence of non-structural measures and individual adaptation. Moreover, flood studies dominated, with few articles addressing landslides, mass movement, and other sediment-related hazards.
Therefore, advancing the understanding of these socio-hydrological dynamics requires integrating preparedness, vulnerability, and risk perception into multi-hazard assessments. Furthermore, the role of non-structural measures in generating unintended consequences should be further studies. This comprehensive approach would enable a better understanding of the diversity of scenarios where the SDP and LE can manifest.
How to cite: Fusinato, E., Kobiyama, M., and de Brito, M. M.: When risk reduction backfires: a systematic review of the safe development paradox, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-509, https://doi.org/10.5194/egusphere-egu26-509, 2026.
This presentation will introduce the Climate Collaboratorium, a transdisciplinary and participatory research project uniting groundwater science, social research, and local stakeholders in the Sorbian community of Rietschen, Germany. We will present the project’s innovative framework, focusing on the co-development of a conceptual site model through stakeholder workshops involving representatives from fisheries, mining, public authorities (engaged in groundwater management), and civil society. Drawing on regional climate projections, multiple groundwater recharge estimation methods, and locally developed socio-economic scenarios, we integrate hydrogeological and social-ecological data into a dynamic numerical platform to simulate future groundwater responses under diverse adaptation pathways. Preliminary results highlight the identification of key vulnerabilities, potential synergies, and trade-offs between ecological and social dimensions. Our approach further incorporates creative, participatory scenario processes to support local engagement, broaden understanding of groundwater processes, and support sustainable water governance. Comparable studies are conducted in Canada, the UK, and the USA, allowing for a broader perspective to identify common challenges and unique solutions for better climate adaption. This presentation will detail the collaborative modelling approach, early project insights, and implications for sustainable, community-based groundwater management under climate change.
How to cite: Hartmann, A., Agudelo Mendieta, T. S., Chen, Z., Chun, K. P., Ayeh, D., and Leipold, S.: The Climate Collaboratorium: A Transdisciplinary Approach to Groundwater Modelling for Climate Adaptation in the Sorbian Community of Rietschen (Görlitz District, Germany), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18036, https://doi.org/10.5194/egusphere-egu26-18036, 2026.
Flood risk is shaped by societal processes, such as “levee effect” and “adaptation effect”. Even though such feedbacks can now be captured by quantitative socio-hydrological models, they have been limited to small case studies due to lack of data. The aim of the European Socio-Hydrological Model (EuroSoHo) is to quantify past and future flood risk dynamics across the continent considering the spatially and temporarily varying human-water feedbacks.
This contribution presents the conceptual framework, outlines methodologies underlying the model, indicates how the necessary data will be obtained and what challenges will need to be addressed in further research. EuroSoHo will be a probabilistic, system dynamics model calibrated using a vast array of historical data covering years 1950-2025. Information from the HANZE (Historical Analysis of Natural HaZards in Europe) database will provide dates, locations and impacts (fatalities, population affected, economic loss) of floods, as well as their hydrological intensity in more than 1400 regions in 42 countries. Dedicated data collection of floodplain exposure changes and flood protection levels will further support establishing values of socio-hydrological parameters (e.g. preparedness, awareness, reactiveness or risk aversion) individually for each region within a uniform framework.
Based on the historical developments of human-water feedbacks, EuroSoHo will be applied to projections of future climate and socioeconomic pathways to estimate the actual changes in future flood risk until 2100. Further, EuroSoHo will quantify the costs and benefits of improving dikes, extending individual preparedness, restrictions on exposure growth, and relocation considering their system-wide positive and negative effects. The results will indicate which combination of adaptation strategies would be most effective under the uncertainty of future climate and socioeconomic developments as well as the unknowable timing of hydrological extremes.
How to cite: Paprotny, D.: The European Socio-Hydrological Model: concept, methods and challenges, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3319, https://doi.org/10.5194/egusphere-egu26-3319, 2026.
The Panta Rhei Scientific Decade (2013–2022) has generated major advances in understanding how hydrological processes and human systems coevolve. This contribution presents the key results synthesized in the book Coevolution and Prediction of Coupled Human–Water Systems, which consolidates insights from over 160 authors and global case studies spanning floods, droughts, agriculture, and transboundary rivers.
The synthesis identifies recurring coevolutionary patterns across diverse contexts, showing how human interventions—such as flood protection, irrigation expansion, and institutional reforms—reshape hydrological dynamics and, through feedbacks in behavior, governance, and economics, produce unintended consequences over time. A central result is the development of a six-component anatomy of coupled human–water systems, integrating hydrology, infrastructure, institutions, society, the economy, and the environment into a unified analytical framework. The book further introduces the concept of critical pathways to identify dominant sequences of interactions that drive risk amplification, maladaptation, or resilience.
Together, these results advance sociohydrology from isolated case studies toward a generalizable science of human–water coevolution, offering practical insights for anticipating long-term system trajectories and informing adaptive water management.
How to cite: Tian, F. and Kreibich, H.: Key Results from the Panta Rhei Synthesis: Coevolution and Prediction of Coupled Human–Water Systems, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4716, https://doi.org/10.5194/egusphere-egu26-4716, 2026.
