The Bagnold Medal Lectures from the medallists from 2020 and 2021 will be presented in this flagship GM session. The session will be introduced by the GM President, Daniel R. Parsons and citations given for each of the Medallists.

Landscapes, and how they change over time, provide the foundations of life and affect the ecosystems and human activities that can exist on Earth. Yet, there appears to be no single axis of causality between landscape and Earth surface processes, but rather, each entity can exert a simultaneous influence on the other over a wide range of temporal and spatial scales. We are just starting to realise and explore the modes, trajectories and effects of these coupled systems, and to trace and infer the often non-linear feedback mechanisms.
Geomorphology inevitably stands in the center of an emerging science devoted to the Earth's surface, where strong couplings link human dynamics, biology, biochemistry, geochemistry, geology, hydrology, geomorphology, soil science, and atmospheric dynamics, including past and ongoing climate changes.
Motivated by the importance of understanding Earth surface interactions, couplings and feedbacks on a rapidly changing globe, this session will bring together a series of invited speakers to provide insights and perspectives on this hot topic from across the field of geomorphology.

Biogeomorphology addresses the two-way interaction between biotic and abiotic elements that shape landscapes at various spatio-temporal scales. Yet, developing theory, methods and quantifying processes at the abiotic/biotic interface remains challenging due to the interdisciplinarity of biogeomorphology, integrating concepts from ecology, evolutionary biology, engineering, geomorphology, geology and Quaternary science. On the other side, there is an urgent need to understand the interactions among abiotic and biotic processes in natural and managed systems to adapt to for instance climate change.
Consequently, a wide range of interdisciplinary projects in fields related to biogeomorphology have emerged. Such projects have included field, computational, and laboratory studies across a wide range of scales to understand the effects of underlying physical and ecological processes on biogeomorphic interactions.
This session focuses on the lessons learned from such approaches: advantages, limitations, best practices, and the future of the discipline of biogeomorphology. Research topics include, but are not limited to: 1) Biogeomorphic processes, rates and feedbacks, 2) Organism-Habitat interaction, 3) Biota as ecosystem engineers, 4) Effects of biogeomorphic interactions on nutrient and pollutant transport, 5) Biogeomorphology for the development of nature-based-solutions.

Almost 30 years of developing the concept of geodiversity in geosciences provides a robust foundation for moving to the issue of synthesizing the existing knowledge and methods of assessing geodiversity and to disseminate the achievements of this concept.
1. The spatial and temporal scales. On what cartographic scale should the source materials be useful for determining the degree of geodiversity? Can geodiversity be considered on a local, regional, national, continental and global scale? Having in place geodiversity (stationary, at a given time of observation/assessment) and dynamic geodiversity at your disposal - how deep, how far can you reach the past and the future in geodiversity assessments of any area? Can geodiversity be determined in a palaeogeographic/geological context? How can you use geodiversity to describe geosites, geoparks, landscapes, and other forms of geoconservation? How to translate geodiversity values into geoheritage measures?
2. The lack of a standard for geodiversity assessment. Is the quality or quantity (number) of assessed geodiversity features important? How to transform qualitative assessments into quantitative assessments, so that you can easily compare different areas in terms of their substantive value, not to mention independence from the spatial and temporal scale? These issues are related to the problem of uncertainty in geodiversity assessments. This problem affects applied geodiversity studies as well, limiting further qualitative/qualitative assessment of abiotic ecosystem services. So what should be the standards of this geodiversity assessment to minimize errors in assessments?
3. If we find a consensus in establishing a standard for geodiversity assessment, how to apply the developed standard at geoconservation and geoheritage? How to consider such a standard universally acceptable? What forms of activity should best promote the idea of geodiversity? How to implement geodiversity assessments by professionals for different forms of geoconservation and geoheritage? Which ecosystem services should be taken into account in determining the importance of geodiversity for human life? How to make the society aware of the importance of geodiversity in their everyday life? How to extend the geodiversity values to preserve the state of the environment for future generations? How to link the idea of geodiversity with 17 UN SDG? Finally, how should geodiversity values be compared with biodiversity values?

Geomorphic processes (e.g fluvial, erosion, slope, aeolian, glacial) shape landscape and affect sediment fluxes in a variety of environments across different spatial and temporal scales. Quantifying processes requires understanding both the effect of landscape components (natural and anthropic) and dynamics responsible for sediment/soil mobilization, storage and delivery (sources-pathways-sinks).
We welcome contributions using traditional methods and/or innovative techniques (e.g. field-based measurements, compositional analysis, GIS-based morphometry, remote sensing, sediment tracing or fingerprinting, cosmogenic and fallout radionuclides, statistical tools, modelling approaches…) for quantifying morphodynamic and sedimentary processes.
The session seeks contributions from any discipline investigating:
(i) topographic, lithologic, climatic and tectonic controls on sediment production and transport from source to sink;
(ii) connectivity and links among geomorphic components;
(iii) quantification of erosion/sedimentation/weathering rates and their variability in space and time;
(iv) environmental signal propagation in Sediment Routing Systems;
(v) redistribution processes through soil, sediment tracing and particle trajectory;
(vi) autogenic processes regulating sediment transport, temporary storage, and deposition;
(vii) interplay between geo-environmental and anthropic processes in geomorphic and sedimentary dynamics;
(viii) compositional analysis of the erosional products;
(ix) forward modelling of sedimentary and geomorphic response to climate change.
Multi- and inter-disciplinary studies are particularly encouraged. We hope to use the session to discuss different perspectives in the viewpoint of an integrated framework, filling the gaps among disciplines.

Two significant flow hazard cascades have been captured with unprecedented detail, with events in Elliot Creek and Bute Inlet (Canada) and the Chamoli and Uttarakhand (India) both occurring with the past few months. These events both have a suite of background observations and baseline datasets on which to contextually place and explore these flows end events in a depth and breadth of detail that is unprecedented, potentially unlocking new understanding of hazard cascades from source to sink.
We welcome contributions that (i) investigate the processes of production, mobilisation, transport, and deposition of sediment in these two events, (ii) explore the feedbacks between erosion and deposition of the flows through these systems, (iii) consider how these flows shape new understanding of hazards cascades through the source to sink linkages. We invite papers that are observational, analytical or modelling based in their approach, across a variety of temporal and spatial scales. We particularly welcome new and innovative methodologies that show potential to unlock new understanding.

Age models are applied in paleoclimatological, paleogeographic and geomorphologic studies to understand the timing of climatic and environmental change. Multiple independent geochronological dating methods are available to generate robust age models. For example, different kinds of radio isotopic dating, magneto-, bio-, cyclostratigraphy and sedimentological relationships along stratigraphic successions or in different landscape contexts. The integration of these different kinds of geochronological information often poses challenges.
Age-depth or chronological landscape models are the ultimate result of the integration of different geochronological techniques and range from linear interpolation to more complex Bayesian techniques. Invited speakers, Sebastian Breitenbach from CL division and Rachel Smedley from the GM division, will share their experience in several modelling concepts and their application in a range of Quaternary paleoenvironmental and geomorphologic records. The Short Course will provide an overview of age models and the problems one encounters in climate science and geomorphology. Case studies and practical examples are given to present solutions for these challenges. It will prepare the participants from CL, GM and other divisions for independent application of suitable age-depth models to their climate or geomorphologic data. For registration please send a request via this email address (ecs-cl@egu.eu) prior to 15th April.

Water is our planet’s most vital resource, and the primary agent in some of the biggest hazards facing society and nature. The twin pressures of population growth and a rapidly changing global climate act as multipliers of water’s value and of water-related hazards.

River streamflow is one of the most crucial hydrological variables for ecology, for people and industry, for flood risk management and for understanding long term changes to the hydrological regime. However, despite significant efforts, long-term, spatially dense monitoring networks remain scarce, and even the best monitoring networks can fail to perform when faced with extreme conditions, and lack the precision and spatial coverage to fully represent crucial aspects of the hydrological cycle.

Happily, a number of new technologies and techniques are emerging which show great potential to meet these challenges. In this context, this session focuses on:
1) Innovative methodologies for measuring/modelling/estimating river stream flows;
2) Real-time acquisition of hydrological variables;
3) Remote sensing for hydrological & morphological monitoring;
4) Measuring extreme conditions associated with a changing climate;
5) Measurement of sudden-onset extreme flows associated with catastrophic events;
6) Strategies to quantify and describe hydro-morphological evolution of rivers;
7) New methods to cope with data-scarce environments;
8) Inter-comparison of innovative & classical models and approaches;
9) Evolution and refinement of existing methods;
10) Guidelines and standards for hydro-morphological streamflow monitoring;
11) Quantification of uncertainties;
12) Development of expert networks to advance methods.

Contributions are welcome with an emphasis on innovation, efficiency, operator safety, and meeting the growing challenges associated with the changing climate, and with natural and anthropogenically driven disasters such as dam failures and flash floods.

Additionally, presentations will be welcomed which explore options for greater collaboration in advancing riverflow methods and which link innovative research to operational monitoring.

This session is sponsored by the COST Action CA16219, Harmonisation of UAS techniques for agricultural and natural ecosystems monitoring (HARMONIOUS).

Sedimentary processes in aquatic environments, including entrainment, transport and deposition of sediment by hydrodynamic mechanisms, are key features for various research disciplines, e.g. geomorphology and paleoclimatology or hydraulics and river engineering. An accurate evaluation of entrainment, transport and deposition rates, conditioning river channel morphology and bed composition, is fundamental for an adequate development of conceptual sediment budget models and for the calibration and validation of numerical tools.
The main goal of this session is to bring together the community of scientists, scholars and engineers, investigating, teaching and applying novel measurement techniques and monitoring concepts, which are crucial to determine sedimentary and hydro-morphological processes in rivers, lakes and reservoirs, estuaries as well as in coastal and maritime environments. Within the focus of this session are the evaluation and quantification of bed load and suspended load, flocculation, settling, and re-suspension of such processes relevant to morphological channel changes as bed form development, horizontal channel migration, bed armouring and colmation.
Contributions are welcome with a particular focus on single and combined measurement techniques, on post-processing methods as well as on innovative and advanced monitoring concepts for field applications. Furthermore, we welcome contributions containing recent results in a temporal and spatial scale on sediment budgets as well as on sedimentary and morphodynamics processes in open water environments.
Contributions may refer, but are not restricted, to:
- measurements of suspended sediment transport in open water environments, e.g. with optical, acoustical, traditional sampling methods or others;
- measurements of bed load transport, e.g. with bed load samplers, sediment traps, tracers or acoustic and optical methods;
- determination of sediment characteristics, e.g. with mechanical bed material samplers or freeze core technique;
- measurements of critical bed shear stress of cohesive sediments, e.g. with benthic flumes or miscellaneous devices;
- monitoring of morphological changes like lake and reservoir sedimentation, bank erosion or bed armouring, meandering migration, river bends evolution;
- measuring networks / multiple point datasets;
- monitoring concepts including case studies;
- in-situ as well as laboratory calibration of measurement data;

Smart monitoring and observation systems for hazards, including satellites, seismometers, global networks, uncrewed vehicles (e.g., UAV), and other linked devices, have become increasingly abundant. With these data, we observe our Earth’s restless nature and work towards improving our understanding of hazard processes such as landslides, debris flows, earthquakes, floods, storms, volcanic eruptions, and tsunamis. The large amount of data we have now accumulated with diverse measurements presents an opportunity for earth scientists to employ statistically driven approaches that speed up data processing, improve model forecasts, and give insights into the underlying physical processes. Such big-data approaches are supported by the wider scientific, computational, and statistical research communities who are constantly developing data science and machine learning techniques and software. Hence, data science and machine learning methods are rapidly impacting the fields of geohazards. In this session, we will see research into hazards spanning a broad range of time and spatial scales.

Geomorphometry and geomorphological mapping are important tools used for understanding landscape processes and dynamics on Earth and other planetary bodies. The recent rapid advances in technology and data collection methods has made available vast quantities of geospatial data for such morphometric analysis and mapping, with the geospatial data offering unprecedented spatio-temporal range, density, and resolution, but it also created new challenges in terms of data processing and analysis.

This inter-disciplinary session on geomorphometry and landform mapping aims to bridge the gap between process-focused research fields and the technical domain where geospatial products and analytical methods are developed. The increasing availability of a wide range of geospatial datasets requires the continued development of new tools and analytical approaches as well as landform/landscape classifications. However, a potential lack of communication across disciplines results in efforts to be mainly focused on problems within individual fields. We aim to foster collaboration and the sharing of ideas across subject-boundaries, between technique developers and users, enabling us as a community to fully exploit the wealth of geospatial data that is now available.

We welcome perspectives on geomorphometry and landform mapping from ANY discipline (e.g. geomorphology, planetary science, natural hazard assessment, computer science, remote sensing). This session aims to showcase both technical and applied studies, and we welcome contributions that present (a) new techniques for collecting or deriving geospatial data products, (b) novel tools for analysing geospatial data and extracting innovative geomorphometric variables, (c) mapping and/or morphometric analysis of specific landforms as well as whole landscapes, and (d) mapping and/or morphometric analysis of newly available geospatial datasets. Contributions that demonstrate multi-method or inter-disciplinary approaches are particularly encouraged. We also actively encourage contributors to present tools/methods that are “in development”.

Seismic techniques are becoming widely used to detect and quantitatively characterise a wide variety of natural processes occurring at the Earth’s surface. These processes include mass movements such as landslides, rock falls, debris flows and lahars; glacial phenomena such as icequakes, glacier calving/serac falls, glacier melt and supra- to sub-glacial hydrology; snow avalanches; water storage and water dynamics phenomena such as water table changes, river flow turbulence and fluvial sediment transport. Where other methods often provide limited spatial and temporal coverage, seismic observations allow recovering sequences of events with high temporal resolution and over large areas. These observational capabilities allow establishing connections with meteorological drivers, and give unprecedented insights on the underlying physics of the various Earth’s surface processes as well as on their interactions (chains of events). These capabilities are also of first interest for real time hazards monitoring and early warning purposes. In particular, seismic monitoring techniques can provide relevant information on the dynamics of flows and unstable slopes, and thus allow for the identification of precursory patterns of hazardous events and timely warning.

This session aims at bringing together scientists who use seismic methods to study Earth surface dynamics. We invite contributions from the field of geomorphology, cryospheric sciences, seismology, natural hazards, volcanology, soil system sciences and hydrology. Theoretical, field based and experimental approaches are highly welcome.

Solicited presenter: Kate Allstadt - USGS Geologic Hazards Science Center, Golden, CO, USA

Numerical frameworks are essential for understanding and interpreting landscape evolution. Over recent decades, geochronological techniques such as luminescence dating, cosmogenic nuclides and thermochronology have improved in accuracy, precision and temporal range. Developments in geochronological methods, data treatment and landscape evolution models have provided new insights into the timing, duration and intensity of landscape evolution processes. This combination of temporal constraints and numerical models has enormous potential to improve our understanding of landscape evolution. The session aims to bring together new research in using geochronology and data science to investigate Quaternary landscape change.

This session includes studies of erosional rates and processes, sediment provenance, burial and transport times, bedrock exposure or cooling histories, landscape dynamics, and the examination of potential biases and discordances in geochronological data and model-data comparisons. We welcome contributions that apply novel geochronological techniques, combine different geochronological techniques, combine numerical age constraints with landscape evolution models to determine rates and timing of landscape change as well as stochastic events, or that highlight the latest developments and open questions in the application of geochronometers to landscape evolution problems.

A key goal within geomorphic research is understanding the processes linking topographic form, erosion rates, sediment production, transport and deposition, and external forcings such as tectonics, biotic or climatic. Numerical modelling, by allowing the creation of controlled analogues of natural systems, provides exciting opportunities to explore landscape evolution and generate testable predictions.

In this session, we invite contributions that use numerical modelling to investigate landscape evolution in a broad sense, and over a range of spatial and temporal scales. We welcome studies using models to constrain one or more of: erosion rates and processes, sediment production, transport and deposition, and biotic, climatic or tectonic forcings. We also particularly wish to highlight studies that combine numerical modelling with direct Earth surface process monitoring techniques, such as topographic, field, stratigraphic, geophysical or geochronological data. Contributions using numerical models to unravel the interaction between deep processes, such as mantle dynamics, or biotic processes with topographic patterns are further encouraged. There is no geographical restriction: studies may be focused on mountain environments or sedimentary basins, or they may establish links between the two.

Recent advances in image collection, e.g. using uncrewed aerial vehicles (UAVs), and topographic measurements, e.g. using terrestrial or airborne LiDAR, are providing an unprecedented insight into landscape and process characterization in geosciences. In parallel, historical data including terrestrial, aerial, and satellite photos as well as historical digital elevation models (DEMs), can extend high-resolution time series and offer exciting potential to distinguish anthropogenic from natural causes of environmental change and to reconstruct the long-term evolution of the surface from local to landscape scale.

For both historic and contemporary scenarios, the rise of techniques with ‘structure from motion’ (SfM) processing has democratized data access and offers a new measurement paradigm to geoscientists. Photogrammetric and remote sensing data are now available on spatial scales from millimetres to kilometres and over durations of single events to lasting time series (e.g. from sub-second to decadal-duration time-lapse), allowing the evaluation of event magnitude and frequency interrelationships.

The session welcomes contributions from a broad range of geoscience disciplines such as geomorphology, cryosphere, volcanology, hydrology, bio-geosciences, and geology, addressing methodological and applied studies. Our goal is to create a diversified and interdisciplinary session to explore the potential, limitations, and challenges of topographic datasets for the reconstruction and interpretation of past and present 2D and 3D changes in different environments and processes. We further encourage contributions describing workflows that optimize data acquisition and processing to guarantee acceptable accuracies and to automate data application (e.g. geomorphic feature detection and tracking), and field-based experimental studies using novel multi-instrument and multi-scale methodologies. This session invites contributions on the state of the art and the latest developments in i) modern photogrammetric and topographic measurements, ii) remote sensing techniques as well as applications, iii) modelling technologies, and iv) data processing tools, for instance, using machine learning approaches.

The introduction of terrestrial cosmogenic nuclides as a geochronology technique provided an important quantitative tool that spurred large developments in geomorphology and it continues to be an essential tool in this field. Cosmogenic nuclides are produced primarily in the top two meters of Earth’s surface, meaning they can be used to provide important information on the exposure ages of features at the surface, like river terraces, fault scarps or glacial moraines, burial ages of deep deposits, as well as quantitative information on the rates of surface processes, like erosion or weathering. Continued technique development and creative applications both continue to expand the ways we can use cosmogenic nuclides.

This session explores both technique developments and novel applications of cosmogenic nuclides, inviting projects at any stage from early development to well-established methods applied to novel situations. We invite any type of cosmogenic nuclide technique developments, including new measurement methods, laboratory techniques, modelling, or theoretical advancements. All cosmogenic nuclide applications in any field are welcome, but we especially encourage contributions using multiple nuclides, combinations with other geochronology techniques, and other creative applications.

The Quaternary Period (last 2.6 million years) is characterized by frequent and abrupt climate swings that were accompanied by rapid environmental change. Studying these changes requires accurate and precise dating methods that can be effectively applied to environmental archives. A range of different methods or a combination of various dating techniques can be used, depending on the archive, time range, and research question. Varve counting and dendrochronology allow for the construction of high-resolution chronologies, whereas radiometric methods (radiocarbon, cosmogenic in-situ, U-Th) and luminescence dating provide independent anchors for chronologies that span over longer timescales. We particularly welcome contributions that aim to (1) reduce, quantify and express dating uncertainties in any dating method, including high-resolution radiocarbon approaches; (2) use established geochronological methods to answer new questions; (3) use new methods to address longstanding issues, or; (4) combine different chronometric techniques for improved results, including the analysis of chronological datasets with novel methods, e.g. Bayesian age-depth modeling. Applications may aim to understand long-term landscape evolution, quantify rates of geomorphological processes, or provide chronologies for records of climate change.

Debris flows are among the most dangerous natural hazards that threaten people and infrastructures in both mountainous and volcanic areas. The study of the initiation and dynamics of debris flows, along with the characterization of the associated erosion/deposition processes, is of paramount importance for hazard assessment, land-use planning and design of mitigation measures, including early warning systems. In addition, the impacts of climate change on debris-flow activity must be considered and carefully analysed, as the number of mountain areas prone to these events may increase in future.
A growing number of scientists with diverse backgrounds are studying debris flows and lahars. The difficulties in measuring parameters related to their initiation and propagation have progressively prompted research into a wide variety of laboratory experiments and monitoring studies. However, there is a need of improving the quality of instrumental observations that would provide knowledge for more accurate hazards maps and modeling. Nowadays, the combination of distributed sensor networks and remote sensing techniques represents a unique opportunity to gather direct observations of debris flows to better constrain their physical properties.
Scientists working in the field of debris flows are invited to present their recent advancements. In addition, contributions from practitioners and decision makers are also welcome. Topics of the session include: field studies and documentation, mechanics of debris-flow initiation and propagation, laboratory experiments, modeling, monitoring, impacts of climate change on debris-flow activity, hazard and risk assessment and mapping, early warning, and alarm systems.

Rockfalls, rockslides and rock avalanches are among the primary hazards in steep terrain. To better understand the processes driving rock slope degradation, mechanisms contributing to the triggering, transport, and deposition of resulting rock slope instabilities, and mitigation measures for associated hazards, we must develop insight into both the physics of intact and rock mass failure and the dynamics of transport processes.

This session aims to bring together state-of-the-art methods for predicting, assessing, quantifying, and protecting against rock slope hazards. We seek innovative contributions from investigators dealing with all stages of rock slope hazards, from weathering and/or damage accumulation, through detachment, transport and deposition, and finally to the development of protection and mitigation measures. In particular, we seek studies presenting new theoretical, numerical or probabilistic modelling approaches, novel data sets derived from laboratory, in situ, or remote sensing applications, and state-of-the-art approaches to social, structural, or natural protection measures.

The global increase in damaging landslide events is raising the attention of governments, practitioners and scientists to develop functional, reliable and (when possible) low cost monitoring strategies. Several case studies have demonstrated how a well-planned monitoring system of landslides is of fundamental importance for long and short-term risk reduction.
Today, the temporal evolution of a landslide is addressed in several ways, encompassing classical and more complex in situ measurements or remotely sensed data acquired from satellite and aerial platforms. All these techniques are adopted for the same final scope: measure landslide motion over time, trying to forecast its future evolution or at least to reconstruct its recent past. Real time, near-real time and deferred time strategies can be profitably used for landslide monitoring, depending on the type of phenomenon, the selected monitoring tool, and the acceptable level of risk.
The session follows the general objectives of the International Consortium on Landslides, namely: (i) promote landslide research for the benefit of society, (ii) integrate geosciences and technology within the cultural and social contexts to evaluate landslide risk, and (iii) combine and coordinate international expertise.
Considering these key conceptual drivers, we aim to present successful monitoring experiences worldwide based on both in situ and/or remotely sensed data. The integration and synergic use of different techniques is welcome, as well as newly developed tools or data analysis approaches (focusing on big data management). We expect case studies in which multi-temporal and multi-platform monitoring data are exploited for risk management and Civil Protection aims with positive effects in social and economic terms.

This session covers both new scientific approaches and state-of-the-art techniques for investigating landslides, including Earth Observation (EO), Geophysical Surveying (GS) and close-range Remote Sensing techniques (RS).

A series of remarkable technological progresses are driven new scientific opportunities to better understand landslide dynamics worldwide, including integrated information about rheological properties, water content, rate of deformation and time-varying changes of these parameters through seasonal changes and/or progressive slope damage.

This session welcomes innovative contributions and lessons learned from significant case studies and/or original methods aiming to increase our capability to detect, model and predict landslide processes at different scales, from site specific to regional studies, and over multiple dimensions (e.g. 2D, 3D and 4D).

A special emphasis is expected not only on the particularities of data collection from different platforms (e.g. satellite, aerial, UAV, Ground Based...) and locations (e.g. surface- and borehole-based geophysics) but also on new solutions for digesting and interpreting datasets of high spatiotemporal resolution, landslide characterization, monitoring, modelling, as well as their integration on real-time EWS, rapid mapping and other prevention and protection initiatives. Examples of previous submissions include using one or more of the following techniques: optical and radar sensors, new satellite constellations (including the emergence of the Sentinel-1A and 1B), Remotely Piloted Aircraft Systems (RPAS) / Unpiloted Aerial Vehicles (UAVs) / drones, high spatial resolution airborne LiDAR missions, terrestrial LIDAR, Structure-from-Motion (SfM) photogrammetry, time-lapse cameras, multi-temporal DInSAR, GPS surveying, Seismic Reflection, Surface Waves Analysis, Geophysical Tomography (seismic and electrical), Seismic Ambient Vibrations, Acoustic Emissions, Electro-Magnetic surveys, low-cost sensors, commercial use of small satellites, Multi-Spectral images, etc. Other pioneering applications using big data treatment techniques, data-driven approaches and/or open code initiatives for investigating mass movements using the above-described techniques will also be very welcomed.

GUEST SPEAKER (to be confirmed). Previous guest speakers include prof. J. Chambers (British Geological Survey - UK) and prof. D. Jongmans (Isterre, Université Grenoble Alpes - France).

Large rock slope instabilities have been recognised under very different geological and environmental conditions, lithological and geological domains, and on other planets. Slow to extremely fast moving, complex mass movements have been recognized, sometimes described as interrelated or as evolution stages of a same phenomenon. Many types of slope instabilities can be grouped within this broad class, presenting different types of hazard and risk. This phenomena, triggered by earthquakes, rainfall, snowmelt or deglaciation can originate relevant cascade events (e.g. tsunamis, landslide dams and overtopping, flooding).
Major aspects of these instabilities are still debated:
- distribution both on Earth and other planets;
- triggering and controlling factors and events;
- dating of initial movements and reactivation episodes;
- style and state of past and present activity;
- passive and/or active control of structural features;
- possible displacement evolution and modelling;
- hazard assessment inclusive of cascade events;
- influence of anthropogenic factors and effects on structures;
- role on the erosional and sediment yield regime;
- technologies for monitoring and warning systems, and the interpretation of monitoring data.
Study of these instabilities is interdisciplinar and multidisciplinar. Site investigation, geophysical survey and dating techniques can support geometrical and geomechanical characterization, recognition of activity episodes, monitoring data interpretation for warning thresholds. Different hydrologic boundary conditions and hydrochemistry are involved, both at failure and during reactivations. Modelling is a key element for understanding and evaluating instability and failure (initiation, propagation), triggering (rainfall, seismicity, volcanic eruption, deglaciation), collapse, and secondary failures as well as the effect on the local and regional geomorphological evolution (e.g. sediment yield). Cascade-like events are definitively a possible result and advanced modeling techniques are requested for studying these phenomena and for reliable and robust hazard zonation. Size and evolution of large instabilities require major efforts when assessing the potential impacts on structures and infrastructures, and human activities enforcing a deep understanding and modeling. On the other hand, instabilities on other planets can support indirect environmental and geomechanical characterization.

Many natural hazards can interact with each other and lead to or exacerbate the effects of additional catastrophic events, such as landslides following earthquakes, floods following snow-avalanches or landslides and floods induced simultaneously by heavy rainfall. According to the 2019 IPCC special report, the frequency and magnitude of mountain hazards, i.e. snow avalanches, floods due to glacier lake outburst (GLOF), flash-floods, rockfalls and landslides, are projected to increase in a scale never seen, potentially impacting new locations and/or occurring in different seasons than previously. In combination with growth in the population and economy, this changing landscape of mountain hazards will dramatically increase the risk to local populations, leading to growing economic damages in mountainous regions. Prediction of the areas threatened by such processes are a key part of hazard assessment in mountainous regions. Whatever the material transported (debris, snow, etc.), the mass wasting process involves determining the initiation mechanisms, initial volume, physical transport, and probable entrainment processes and as well as deposition mechanisms. Because of the number of scientific disciplines needed to solve it, there is a substantial benefit from inter- and transdisciplinary research. This session aims to serve as a forum, allowing discussion and debate on the future development of the field. In particular, we encourage presentations ranging from innovative monitoring and documentation methods related to hazard processes in mountain settings to studies focusing on an improved mechanical understanding of the physical processes involved, including modelling, laboratory research, and theoretical studies.

Many regions worldwide are coping with the climatic global change, which is modifying the water cycle and is increasing the occurrence of extreme hydro-meteorological events. Floods and landslides across a territory could increase significantly respect to actual and past scenarios, causing a modification of the susceptibility of a region and of the frequency of natural hazards.
The use of techniques able to monitor and to improve the prediction of these phenomena at different scales and in scarcely instrumented regions is fundamental. Soil moisture and rainfall estimates measured through remote sensing techniques can furnish reliable and widespread data at different scales. For satellite rainfall measures, state-of-the-art products cover time series of tens of years (e.g., TRMM Multisatellite Precipitation Analysis, Global Precipitation Measurement, EUMETSAT). Regarding soil moisture, different products can bring reliable measurements from a local/landscape to continental scales (e.g., SMMR, AMSR2, SMOS, SMAP, Metop/ASCAT, Sentinel). Innovative products, as soil moisture derived rainfall, allow to retrieve rainfall from different satellite soil moisture products or integrating field measurements of precipitation. Thanks to the improvement of the spatial and temporal resolutions of all of these products, they could become a fundamental tool also for early warning system strategies.
This session aims to collect and present researches concerning the most recent progress on the use of soil moisture and rainfall data from remote sensing for the monitoring and the prediction of landslides and floods. Those phenomena can cause hazards and risks towards population and anthropic elements. We encourage presentations related to:
• inter-comparison and inter-validation between land surface models, remote sensing approaches and in-situ validation networks;
• evaluation and trend analysis of soil moisture or rainfall satellite time series for monitoring landslides or floods and for identifying their possible triggering conditions;
• implementation of satellite measures of rainfall and soil moisture in physically-based or data-driven methods for the prediction of landslides and floods;
• use of remote sensing products of soil moisture and rainfall in early warning system tools;
• use of remote sensing products for investigating the effects of climatic global changes on the susceptibility and hazards towards landslides and floods.

Soil is the largest carbon (C) reservoir in terrestrial ecosystems with twice the amount of atmospheric C and three times the amount in terrestrial vegetation. Carbon related ecosystem services include retention of water and nutrients, promoting soil fertility and productivity and soil resistance to erosion. In addition, changes in the soil C can have strong implications for greenhouse gas emissions from soil with implications in environmental health.

Drivers controlling C pools and its dynamics are multiple (e.g. land use/vegetation cover, climate, texture and bedrock, topography, soil microbial community, soil erosion rates, soil and other environment management practices, etc. ) and some of them are mutually interacting. Also, rate of net soil C loss can be high in some environments due to both climatic constrains or management. Thus, investigation of C dynamics should be addressed with regards to the climate change and climatic extreme events to provide a better understanding of carbon stabilization processes and thus support decision making in soil management and climate adaptation strategies.

The present session highlights the importance of soil C changes, and the interaction among the mechanisms affecting C concentration and stocks in soil. Discussion about the proxies to measure and model C stocks, with special emphasis to cropping systems and natural/semi-natural areas, is encouraged. These proxies should be approached at varying the availability of soil and environment information, including, e.g., soil texture, rainfall, temperature, bulk density, land use and land management, or proximal and remote sensing properties. Studies presented in this session can aim to a wealth of aims, including soil fertility, provision of ecosystem services, and their changes, and the implication for economy, policy, and decision making.

Types of contribution appreciated include, but are not limited to, definitive and intermediate results; project outcomes; proposal of methods or sampling and modelling strategies, and the assessment of their effectiveness; projection of previous results at the light of climate change and climatic extremes; literature surveys, reviews, and meta-analysis. These works will be evaluated at the light of the organisation of a special issue in an impacted journal

Well-designed experiments, measurement and modelling approaches are crucial methodologies in Soil Science, Geomorphology and Hydrology.

Depending on the specific research topic, a great variety of tempo-spatial scales is addressed. From raindrop impact and dust emission on field scale to the shaping of landscapes.

This virtual PICO-Session presents experiments, measurements and modelling approaches in the laboratory and the field investigating processes and quantities of soil detachment by wind, splash erosion and subsurface particle transport highlighting the role of vegetation, land use and harmonisation of experiments.

Dissolution, precipitation and chemical reactions between infiltrating fluid and rock matrix alter the composition and structure of the rock, either creating or destroying flow paths. Strong, nonlinear couplings between the chemical reactions at mineral surfaces and fluid motion in the pores often leads to the formation of intricate patterns: networks of caves and sinkholes in karst area, wormholes induced by the acidization of petroleum wells, porous channels created during the ascent of magma through peridotite rocks. Dissolution and precipitation processes are also relevant in many industrial applications: dissolution of carbonate rocks by CO2-saturated water can reduce the efficiency of CO2 sequestration, mineral scaling reduces the effectiveness of heat extraction from thermal reservoirs, acid rain degrades carbonate-stone monuments and building materials.

With the advent of modern experimental techniques, these processes can now be studied at the microscale, with a direct visualization of the evolving pore geometry. On the other hand, the increase of computational power and algorithmic improvements now make it possible to simulate laboratory-scale flows while still resolving the flow and transport processes at the pore-scale.

We invite contributions that seek a deeper understanding of reactive flow processes through interdisciplinary work combining experiments or field observations with theoretical or computational modeling. We seek submissions covering a wide range of spatial and temporal scales: from table-top experiments and pore-scale numerical models to the hydrological and geomorphological modelling at the field scale. We also invite contributions from related fields, including the processes involving coupling of the flow with phase transitions (evaporation, sublimation, melting and solidification).

The transfer of sediments and associated contaminants play an important role in catchment ecosystems as they directly influence water quality, habitat conditions and biogeochemical cycles. Contaminants may include heavy metals, pesticides, nutrients, radionuclides, and various organic, as well as organometallic compounds. The environmental risk posed by sediment-bound contaminants is largely determined by the sources and rate at which sediments are delivered to surface water bodies, the residence time in catchments, lakes and river systems as well as biogeochemical transformation processes. However, the dynamics of sediment and contaminant redistribution is highly variable in space and time due to the complex non-linear processes involved. This session thus focuses on sources, transport pathways, storage and re-mobilization, and travel times of sediments and contaminants across temporal and spatial scales as well as their impact on catchment and freshwater ecosystems.

This session particularly addresses the following issues:
- Delivery rates of sediments and contaminants from various sources (i.e. agriculture, urban areas, mining, industry or natural areas);
- Transport, retention and remobilization of sediments and contaminants in catchments and river reaches;
- Modelling of sediment and contaminant transport on various temporal and spatial scales;
- Biogeochemical controls on contaminant transport and transformation;
- Studies on sedimentary processes and morphodynamics, particularly sediment budgets;
- Linkages between catchment systems and lakes, including reservoirs;
- Analysis of sediment archives to appraise landscape scale variations in sediment and contaminant yield over medium to long time-scales;
- Impacts of sediments and contaminants on floodplain, riparian, hyporheic and other in-stream ecosystems;
- Response of sediment and contaminant dynamics in catchments, lakes and rivers to changing boundary conditions and human actions.

Water and sediments interact at different spatial and temporal scales in freshwaters promoting the development of highly dynamic systems. Erosion, transport and sedimentation are vital processes that shape river morphology. These dynamic processes, in turn, are essential to provide a mosaic of diverse habitat patches for aquatic species and to freshwater ecosystems functioning.
Anthropogenic activities such as flow regulations or dams lead to fragmentation and ecosystem degradation, interfering with natural hydro-morphodynamics and affecting aquatic ecology. In Europe, large efforts are set to restore disturbed river sections to meet the goals of a good ecological status, set by the Water Framework Directive. Experience to date indicates that integrating both physical and ecological processes in river restoration efforts is critical to freshwater ecosystems conservation. In this context, the interdisciplinary field of Ecohydraulics represents the link between abiotic components (e.g. hydrology, hydraulics, geomorphology) and riverine biota (e.g. vegetation, fish, macroinvertebrates). Advances in this field of research are therefore paramount to make future management decisions in freshwater systems.
This session aims at integrating the core research disciplines forming Ecohydraulics, from hydrology, hydraulics, fluvial geomorphology, and biology, but also social aspects to ensure a holistic assessment of rivers, lakes and reservoirs, and to enable the implementation of sustainable restoration measures.
We welcome both fundamental and applied research, presenting approaches at different spatio-temporal scales. They may include holistic tools and methods to improve the assessment, prediction and management of restoration and mitigation measures in aquatic systems, with a focus on the hydrological, fluvial geomorphological, and biological interactions.
Contributions may refer, but are not restricted, to:
- sediment transport, fluvial dynamics and sediment budgets in rivers
- risk analysis and mitigation in fluvial systems
- reservoir sedimentation: processes and management
- large wood and microplastic in aquatic systems
- nature-compatible river engineering and river development
- nature based solutions
- revitalization of river systems (from successful studies to failures in restoration)
- tools and methods (concepts, measurements, monitoring, modelling) to understand the interactions between fluvial processes and their biological responses

Complex hydro-morphological processes, such as sediment erosion, transport, deposition or fan development, affect open water environments, including rivers, estuaries as well as lakes and reservoirs. Consequently, many research tasks as well as practical applications rely on the correct prediction of these processes. During the last decades, numerical models have become a powerful tool in the research fields of hydraulic engineering and geosciences to simulate these hydro-morphological processes. With improved algorithms as well as an ever growing computational power, it became feasible to simulate the interaction of water, sediments and air with high resolution in space and time. In addition, with an increasing quantity and quality of validation data from laboratory experiments and field studies, numerical models are continuously enhanced so that many good examples of sediment transport modelling offer new insights in multiphase processes, e.g. dune development, river bed armoring or density driven transport. Hence, new generations of numerical modelling techniques open up the possibility to explore numerous outstanding research questions related to hydro-morphologic processes.
The main goal of this session is to bring together scientists and engineers, who develop, improve, and apply numerical models of multiphase flows for sediment transport in open water environments. We invite contributions that deal with numerical modelling from small-scale, such as bed structure development, to large-scale interactions, such as long-term development of hydro-morphological processes in rivers, lakes, reservoirs and estuaries.
Contributions may refer, but are not restricted, to:
• Entrainment processes of sediments (from cohesive sediments to armoured river beds)
• Bed load and suspended sediment transport processes (including flocculation processes)
• Simulation of sediment management including planning, operation and maintenance of hydro power plants
• Design and evaluation of restoration measures to revitalize rivers
• Navigation issues, such as sediment replenishment, dredging and erosion induced by ship generated waves
• Flood related issues of long term effects of morphological bed changes on flood security
• Eco-hydraulics such as flow – sediment – vegetation interaction
• Density driven transport

The production, transport, and deposition of sediment govern the fluxes and distribution of solid mass on the surface of the Earth. The frequency, magnitude, and physical and chemical properties of these fluxes are initially controlled by external forcing (climate and tectonics) before being modulated by the complex interplay of surface processes. Understanding the interplay of these processes and how they are affected by external forcing is vital to understanding how sediment fluxes have changed through time.
A growing body of studies continues to develop a process-based understanding of the coupling between climate, tectonics, and the production and transport of solids across catchments. Important insights into sediment recycling and residence time have been provided by recent advances in geochemical and geophysical techniques, highlighting the dynamic nature of sediment transport. However, many challenges remain including; (1) fully quantifying the temporal- and spatial scales of sediment transport, (2) assessing the importance of large and infrequent events in controlling erosion and sediment transport and, (3) bridging the gap between short- and long-term or small- and large-scale records of sediment production and fluxes.
In this session we welcome field-based, experimental, and modelling studies, that (1) constrain mechanisms, rates, and scales of erosion, transport, and deposition processes, (2) analyse the influence of internal and external forcing on these processes, (3) investigate the propagation of geochemical or physical signals across the earth surface (such as changes in sedimentary fluxes, grain size distributions, cosmogenic nuclide concentrations).
Contributions across all temporal and spatial scales are welcome.

Invited presentation : Sebastien Carretier - Delayed sedimentary grains

Soil erosion is a major global soil degradation threat to land, freshwater and oceans. Scientific understanding of all erosional physical processes controlling soil detachment, transportation, and deposition is vital when developing methods and conservation alternatives to minimize the impacts associated with soil degradation.

This session will discuss the State-of-the-Art of the latest soil erosion measurements, monitoring and modelling techniques in agriculture, forest and rangelands. Our main objective is to scientifically discuss soil erosion but also to explore/present solutions that may help farmers and policy makers; supporting the ongoing activities aiming at achieving the SDG Target 15.3 land degradation neutral world by 2030 and the upcoming UN Decade on Ecosystem Restoration (2021-2030). This session will also discuss recent studies supporting improved understanding of gully and rill erosional physical processes, their impact locally, their off-site effects on sedimentation, and subsequent development of mitigation strategies.

Landslides are ubiquitous geomorphological phenomena with potentially catastrophic consequences. In several countries, landslide mortality can be higher than that of any other natural hazard. Predicting landslides is a difficult task that is of both scientific interest and societal relevance that may help save lives and protect individual properties and collective resources. The session focuses on innovative methods and techniques to predict landslide occurrence, including the location, time, size, destructiveness of individual and multiple slope failures. All landslide types are considered, from fast rockfalls to rapid debris flows, from slow slides to very rapid rock avalanches. All geographical scales are considered, from the local to the global scale. Of interest are contributions investigating theoretical aspects of natural hazard prediction, with emphasis on landslide forecasting, including conceptual, mathematical, physical, statistical, numerical and computational problems, and applied contributions demonstrating, with examples, the possibility or the lack of a possibility to predict individual or multiple landslides, or specific landslide characteristics. Of particular interest are contributions aimed at: the evaluation of the quality of landslide forecasts; the comparison of the performance of different forecasting models; the use of landslide forecasts in operational systems; and investigations of the potential for the exploitation of new or emerging technologies e.g., monitoring, computational, Earth observation technologies, in order to improve our ability to predict landslides. We anticipate that the most relevant contributions will be collected in the special issue of an international journal.