H01 Panta Rhei Synthesis: Change in Hydrology and Society

Convener(s): Heidi Kreibich (Panta Rhei, Germany)

Co-Convener(s): Fuqiang Tian (Panta Rhei, China) Giuliano Di Baldassarre (Panta Rhei, Sweden) Hilary McMillan (Panta Rhei, USA) Alberto Montanari (Panta Rhei, Italy)


The IAHS decade “Panta Rhei - Everything Flows” (2013-2023) was dedicated to increasing our knowledge of the interplay between hydrology and society. Research was focused on processes and drivers of change in the water cycle with a strong consideration of the interactions and feedbacks with changing human systems. The general objective was to improve our descriptions and predictions of water resources dynamics to support sustainable development under global change conditions. At the end of this Panta Rhei decade, it is time to synthesize the achievements and reflect together about the remaining challenges. 

This symposium welcomes contributions about the following topics:

  • New data or data acquisition approaches to describe the interplay between hydrology and society
  • Assessment of interactions and feedbacks between communities and local water resources
  • Evaluations of water management interventions and disaster risk reduction actions, including unintended consequences or undesired effects at local, region, and global scales
  • Analysis of human influence on and/or adaptation to hydrological extremes
  • Integrated models or sociohydrological analyses of fully coupled human-water systems
  • Local, regional and global modeling of hydrologic and socio-economic change
  • Case studies from Panta Rhei working groups, IAHS Commissions and beyond

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H02 Detecting the Impacts of Water Management on the Spatial and Temporal Pattern of Natural Water Resources Via Observations, Models and Remote Sensing

Convener(s): Suxia Liu (ICWRS, China)

Co-Convener(s): Yonca Cavus (ICSW, Turkey) María J. Polo (ICRS, Spain) Felipe de Barros (ICWQ, Brazil) Moctar Dembélé (ICSW, Burkina Faso)

Human activities are more and more severely changing the spatial and temporal pattern of natural water resources via many management actions such as long-distance water transfer, dams, irrigation, water and soil conservation, among others. Quantifying these impacts is very important for decision makers to plan the future management of water resources in a sustainable way and to reduce harmful impacts of such management activities for existing water resources systems. Challenges are posed due to a lack of data for the quantification and insufficient models to forecast such impacts. Specific monitoring strategies are required to set up adequate models. Remote sensing as part of earth observations (EO) provides useful tools for the estimation of human-induced changes in water supply and demand. This symposium will focus on monitoring systems and water balance models suitable to develop recommendations for water management planning and operations to mitigate harmful impacts of water resources systems, particularly models that integrate across multiple disciplines (e.g. hydrology, social science, economics and ecology). Special emphasis is given to multi-mission satellite earth observation products in their combination with ground-based monitoring of water resources at a regional scale.

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H03 Floods: Processes, Forecasts, Probabilities, Impact Assessments and Management

Convener(s): Svenja Fischer (ICSH, Germany)

Co-Convener(s): Andreas Schumann (ICWRS, Germany) Günter Blöschl (IAGS PP, Austria) Elena Volpi (ICSH, Italy) Christopher J. White (ICCLAS, UK)


One main aspect of the direct socio-economic relevance of hydrology consists in its ability to predict or to forecast extreme flood events. Prediction refers to the assessment of the probability of a value related to the flood (e.g., the maximum peak discharge during one event) to be exceeded, without specifying the time of occurrence. Forecast refers to a statement of the future development of a variable related to the flood with a specification of the time of occurrence. With regard to their impacts, floods play a very important role for the society in general and human beings living in flood prone areas in particular. Because of missing information and a short memory of harmful events in the past, the public awareness of floods is often low and flood prevention and protection are insufficient in many parts of the world. Existing tools and methods for flood prediction and forecast may be outdated, as new problems have to be considered, e.g., by increases of:

  • uncertainties, caused by climate change and human impacts,
  • changing flood regimes, caused by climate variabilities,
  • relevance of interlinks between atmosphere and river basins in the formation of extreme floods,
  • risks, resulting by the concentration of people and values in river valleys,
  • demand for more reliable and more complex hydrological data for flood design,
  • complexity of flood protection at the river basin scale, where one human intervention may affect the impacts of existing or planned measures in not foreseeable ways and so on.

This session welcomes contributions to various aspects of floods, including but not exclusively processes of flood generation, the assessments of flood probabilities, regionalisation issues, flood forecasting and the need for impact forecasts and other economic aspects of risk management. We encourage submissions that link to the Unsolved Problems in Hydrology (UPH) initiative.

Solicited speakers: Salvatore Grimaldi (University of Tuscia, Italy), Bruno Merz (GFZ Helmholtz Centre Potsdam, Germany)

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H04 Diminishing Lakes and Wetlands: Causes Behind the Process and Actions for Recovery

Convener(s): David Hannah (ICSW, UK)

Co-Convener(s): Gil Mahe (ICSW, France) Yonca Cavus (ICSW, Turkey) Hafzullah Aksoy (ICSW, Turkey) Rahim Barzegar (ICGW, Canada)

Lakes and wetlands, all surface waterscapes in general, are under stress of imbalanced water input and output of their systems. A surplus increases the water level while a deficit will decrease it. Anthropogenic interruption such as the excess water used mainly from the groundwater for irrigation has the greatest negative effect on the surface water courses. Also, water encroachment accelerates the lakes and wetlands to diminish. Of course, the effect of climate change is not negligible either. In this symposium, the issue can be discussed to understand the process itself together with the causes of the lake water level drop and possible actions to take against it. The topic has a very broad range of activities which will allow many disciplines to come together.

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H05 Climate Change and The Water Quality

Convener(s): Elango Lakshmanan (ICWQ, India) Chen Xiaohong (ICWQ, China)

Co-Convener(s): Alena Bartosova (ICWQ, Sweden) Stefan Krause (ICWQ, UK) Hong-yi Li (ICWQ, USA) Bertil Nlend (ICWQ, Cameroon)

The degradation of water quality in recent times is a great threat to the ecosystem. Climate change among the other impacts is also affecting the water quality. Adverse impacts of climate change on water quality are of emerging interest and importance. On the other hand, the assessment of water quality also helps to understand the role of weathering in a river basin on climate change and the carbon cycle. The carbon dynamics of catchments and river basins play a vital role in the process of climate change. The movement of water controls the carbon cycle, and its role is not well understood unlike the role of oceans and land. The role of rivers is significant in the tropical regions of the world. The CO2 outgassing from surface waters to the atmosphere and its temporal and spatial variation is controlling climate change. This session will deal with these aspects with the current studies on the water quality, surface water-groundwater interaction, carbon cycle, riverine flux, organic/inorganic carbon, models etc in the context of climate change.

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H06 The Future of Water Resources Management

Convener(s): Gökçen Uysal (ICWRS, Turkey)

Co-Convener(s): Barry Croke (ICWRS, Australia) Slobodan P. Simonovic (N/A, Canada) Jean-Marie Kileshye Onema (ICWRS, Zimbabwe) Chris Leong (ICWRS, Fiji),Moctar Dembélé (ICSW, Burkina Faso)

Nowadays, society needs more comprehensive and adaptive solutions that can help to meet the global challenges posed by the increasing complexity of water resource systems and increasing uncertainties for a secure, sustainable and more fair water future. These challenges are mainly grouped as: population growth; climatic change; land use change; population distribution and migrations; and interactions between people and the environment. At this point, the “systems approach” provides the most appropriate methodology for current and future challenges in water resources management. This symposium focuses on evaluating the lessons learned from the past cases as well as the future perspective of water resources management which is apprised under better adaptation to challenges, linking past and future with concrete ideas and action plans and providing a future outlook with some possible solutions. The symposium also aims to present multi-disciplinary approaches to tackle these challenges from various fields associated with the future of water resources. Especially contributions are invited with topics related to the “Unsolved Problems in Hydrology” Initiative. Particular questions of interest are here UPH 22: “What are the synergies and tradeoffs between societal goals related to water management (e.g. water-environment-energy-food-health)?” and UPH 23: “What is the role of water in migration, urbanisation and the dynamics of human civilisations, and what are the implications for contemporary water management?”

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H07 Stable Isotopes of Water in the Hydrological Cycle

Convener(s): Przemysław Wachniew (ICT, Poland)

Co-Convener(s): Christine Stumpp (ICT, Germany) Zhonghe Pang (ICT, China) Ravindra Dwidedi (ICT, India) Søren Jessen (Denmark)

Stable isotopic composition of water (d2H, d18O, d17O) is a powerful but underused tool for tracing water partitioning and fluxes across a wide range of environmental scales: from single organisms to ecosystems, from hillslopes to river catchments, from soil profiles to the critical zone, from aquifer to basin scales, from regional to global atmospheric circulation patterns. Stable isotope technique uses spatial and temporal patterns of isotopic signatures of water for a comprehensive understanding of the cycling of matter through the hydrosphere. As such, this inherently interdisciplinary tracer approach is applicable to all compartments of the hydrological cycle. At the same time, proliferation of novel laser spectrometry technique makes determination of the stable isotope compositions more accessible to wide circles of water researchers and practitioners.

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H08 A Familiar Paradigm – Climate Change and the Soil-Sediment Continuum - Resilience, Thresholds, and Adjustments

Convener(s): Adrian Collins (ICCE, UK) Allen Gellis (ICCE, USA)

Co-Convener(s): Paolo Porto (ICCE, Italy) Sergey Chalov (ICCE, Russia) Anatoly Tsyplenkov (ICCE, Russia) Yuri Jacques da Silva (ICCE, Brazil)

Soil is a non-renewable resource and its protection against water erosion is necessary for a sustainable future. Soil particles are mobilised by a range of on-site processes that include soil erosion or river bank erosion and are ultimately delivered to, and through, river systems, via a number of landscape compartments such as hillslopes, river floodplains and estuaries, before entering the ocean. The mobilisation, transfer and storage of sediment within the landscape gives rise to many environmental problems, both on-site and off-site, and their management and control are increasingly seen as an important component of catchment and environmental management. Recent decades have seen important changes in erosion rates and sediment delivery responses to intensification of land use and land use practices. These changes are also driven by climate change via the occurrence of weather extremes that manifest much elevated erosion rates. As a result, significant changes in the spatial incidence of soil erosion and sediment mobilisation and transfer within river catchments have occurred and such responses are projected to continue under both near- and far-future climates. The sustainability of soil resources, river water quality and the hydro-ecological functioning of river catchments is therefore under threat. Contributions investigating the soil-sediment continuum in the context of weather extremes and climate change, including through the consideration of early warning signals, tipping points, resistance or resilience are warmly welcomed.

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H09 Analysis and Prediction of Hydrological Induced Disasters in High Mountain Environment

Convener(s): Ankit Agarwal (India)

Co-Convener(s): Axel Bronstert (Germany) Wolfgang Schwanghart (Germany) Walter Immerzeel (Netherlands) Manoj K. Jain (India)

Hydrological induced extremes such as droughts, floods and heavy-rain-triggered mass movements account for 45% of the fatalities and 74% of the economic losses caused by natural hazards. Mountainous areas owing to unique hydro-climatological, geological and topographical conditions, and partly seismic activity are particularly susceptible to hydrological induces disasters. Furthermore, climate change is affecting hydrological processes particularly in high mountain regions. Rising temperatures and changes in weather patterns likely elevate risks from hydrological hazards such as frequent or intensified periods of water scarcity and heat waves, riverine and flash floods and associated mass movements, or the occurrence of glacial lake outburst floods. Often these hydrological extremes transform into cascading hazards where an initial event causes a downstream chain reaction. Such extreme events induced hazards interfere with increasing population pressure and expansion of settlements along rivers and new infrastructure developments such as roads and hydropower projects. The complexity of hydrological hazards and their underlying processes in mountainous landscape demand scientific efforts and approaches from multiple disciplines. The proposed session aims to compile recent research that analyses and predicts hydrological induced hazards and risks in the high mountainous region. We encourage research submissions from hydrological, hydrodynamic and hydro-sedimentological analysis and modelling, trends and patterns of extremes, analyzing past, present and future hazards and risks through innovative data-analysis, remote sensing, and risk assessment approaches. With the proposed session, we further target to elucidate options for improved risk management and mitigation in the future.

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H10 Transdisciplinary Citizen-Centred Participatory WEFE Nexus Approaches to Achieve Water, Food, Energy and Environment Security

Convener(s): Fernando Nardi (CandHy, Italy)

Co-Convener(s): Maria Cristina Rulli (Italy) Davide Danilo Chiarelli (Italy) Mohammad Merheb (Lebanon)

Society is tackling unprecedented challenges to face increasing urban and industrial pressures and changing population dynamics while meeting the need of achieving water, food, energy and environmental (WEFE) security and protection. Fair and sustainable allocation of natural resources requires multiple economic and social sectors and interest to co-understand and co-identify optimal shared solutions. The wide heterogeneity of policy makers, practitioners, academic disciplines and users involved in the resource use and supply chains and the variety of spatial and temporal scales to be considered when co-demonstrating and projecting actions and scenarios at short, mid and long terms characterize a complex multi-actor multi-sector framework. Transdisciplinarity is, thus, required considering the importance of supporting geo-earth and hydro-meteo-climate sciences with socio-cultural and behavioral dynamics that govern human-environment interactions. These challenges are particularly important today while top-down green, energy and digital transition are moving fast and may risk not to fund suitable and favorable ground at regional and local scales. In recent times, WEFE Nexus modelling approaches based on consolidated bio-physical quantitative models have demonstrated to provide accurate understanding and simulations of complex ecosystem-human-resource interactions from global to local scales, and from long to short time. Those models have also clearly highlighted the pivotal role of the “human variable”. Nonetheless, WEFE Nexus transdisciplinary methods are lacking behind. Social sciences have analogously progressed in recent years in providing qualitative and quantitative methods and strategies, supporting a knowledge, behavioral and action base, to understand and project societal feedbacks to policy actions in relation to climate and environmental protection actions. This session invites contributions from diverse earth, water and environmental scientists with specific focus on collecting outcomes from research and project works including transdisciplinary participatory approaches and collaboration with social scientists and humanities.

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H11 Stochastic Hydrology With Contributions on Methodologies and Applications, for Modeling, Forecasting, Change Assessment, and Uncertainty Quantification

Convener(s): Ashish Sharma (ICHS, Australia)

Co-Convener(s): Elena Volpi (ICSH, Italy) Simon Papalexiou (Canada) Antonio Zarlenga (ICGW, Italy) Alberto Viglione (ICWRS, Italy)

Stochastic hydrology offers efficient tools for characterizing processes in hydroclimatic systems, e.g., for hydrologic design, hydroclimatic systems modeling and forecasting, and water resources management. Theory and application of stochastic processes enables a faithful and consistent representation of natural processes that in many cases outperforms outcomes of physically based models. Stochastic modelling offers the means to mimic the variability of processes in space and time, and to characterize the inherent uncertainty in probabilistic terms. For example, this allows to simulate synthetic space-time fields reproducing the characteristics of the process – the main statistical properties across multiple spatial and temporal scales – for assessing the hydrological impact in a complex and changing environment. This session call for papers developing and discussing stochastics tools to systematically deal with uncertainty, constant or sudden change, and space-time variability, for characterization or simulation (including disaggregation) purposes of hydroclimatic variables such as precipitation, temperature, streamflow, or soil properties. Contributions are invited, for instance, on the improvement of stochastic modeling in hydrology, innovative techniques for identifying model structure, calibrating parameters, assessing uncertainties also based on a Bayesian approach, etc. (see also the unsolved problems 1-4 and 5-8 identified by Blöschl et al., 2019, which are related to time-variability and change and space-variability and scaling, respectively).

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H12 Extremes in Hydroclimatic Systems

Convener(s): Krzysztof Kochanek (ICSH, Poland)

Co-Convener(s): Ilaria Prosdocimi (ICSH, Italy) Salvatore Grimaldi (IAHS VP, Italy) Marco Marani (Italy)

The occurrence of extreme hydroclimatic events has a tremendous impact on society and environment. Hence, there is an urgency in extreme events understanding and modeling, since those events are not fully captured by space and time variability (see also the unsolved problems 9-11 identified by Blöschl et al., 2019). More specifically, it is of fundamental importance to understand which mechanisms rule the occurrence of extreme events, how they emerge from the parent processes and how their occurrence changes in time or space due to external, environmental factors. This session calls for contribution on advances in statistical theory and applications dealing with extremes in hydroclimatic systems, including multivariate statistical tools, Bayesian techniques, global data and their analysis, etc.

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H13 Vegetation and Hydrology Interactions: A Remote Sensing Perspective

Convener(s): María J. Polo (ICRS, Spain)

Co-Convener(s): Gilles Boulet (ICRS, France) Christopher Hopkinson (ICRS, Canada) Amir Aghakouchak (ICRS, USA) Yangbo Chen (ICRS, China)

The dynamic role of vegetation in the water cycle adds complexity for modelling hydrological processes in a warmer and prone-to-extreme climate. Not only direct interactions due to water absorption from roots and transpiration to the atmosphere, but also indirect impacts of changes in the vegetation cover, like post-fire conditions or modified surface roughness after severe drought periods, can exert a significant control on water and energy fluxes, and eventually become drivers of tipping points on the local and global scales. Remote sensing has already achieved relevant progress in observing vegetation conditions and their changes that help to understand and model such interactions. This symposium focuses on the remote sensing capabilities for the dynamic modelling of these two-way water-vegetation feedbacks and aims to bring discussion on RS-supported observation/simulation of critical conditions and both seasonal and long-term processes, and their relationship. As examples, the interactions of vegetation dynamics with snow accumulation/ablation, infiltration/runoff partition and the critical zone, flood extents and recovery potential, evapotranspiration and water-stress controls, groundwater depletion and recharge, among others. Works are welcome to highlight man-induced and/or global warming critical changes, combination of different remote sensing sources, generation of long term time series of vegetation-water processes descriptors/models parameters, combined data assimilation for dynamic modelling of such feedbacks, or early detection of potential tipping points in the water balance and their impacts on different time/spatial scales.

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H14 Improving Understanding of Hydrological Processes Through Water Quality

Convener(s): Alena Bartosova (ICWQ, Sweden)

Co-Convener(s): Stefan Krause (ICWQ, UK) David Hannah (ICSW, UK) Felipe de Barros (ICWQ, Brazil) Roseanna M. Neupauer (ICGW, USA)

Hydrological processes have been studied with various methods, such as direct and indirect measurements, physical modeling, or computer modeling. Knowledge and understanding of hydrological processes can be strengthened by knowledge and understanding of physical and biogeochemical properties of water moving along the individual pathways. Many computational models are now able to simulate various processes such as infiltration, evapotranspiration, soil moisture, groundwater movement, surface runoff, and movement through various soil layers or drainage. This complexity is not yet met by observed data used in the model validation and evaluation, aside from rising use of Earth Observations (EO) data. Data on various constituents carried by water as it moves through different pathways in the hydrosphere have an untapped potential to differentiate the individual pathways, as the constituents may undergo different processes in different environments or media. Water biogeochemistry signatures can reveal patterns about (reactive) flow paths, mixing of sources and residence times as well as define distribution of flows affected by water transfers or divisions. We invite contributions from all aspects of hydrology that investigate synergies between water quality and water quantity, particularly those focusing on understanding of various hydrological processes and pathways. Special emphasis is given to modeling studies and reducing the model equifinality with water quality data.

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H15 The History of Hydrology

Convener(s): Keith Beven (UK)

Co-Convener(s): E. Mario Mendiondo (Brazil) Okke Batelaan (Australia)

In the Centenary year of IAHS in 2022 a new international initiative on the History of Hydrology was started. Through the enthusiasm of some individuals, there have been past efforts to record some of the history of the science and its institutions but these have been somewhat fragmented and often limited in scope. A proposal for a formal IASH Working Group is currently being considered but more than 20 hydrologists from 16 different countries have expressed interest in being actively involved in such a group. This symposium would be aimed at encouraging contributions from countries that are not currently well represented in reviews of the history; encouraging the recording of the contributions of more female hydrologists; and encouraging more recording of the histories of important experimental catchments and hydrological models.

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