Measuring and assessing bedload data is crucial for successful and efficient river management. Hence, understanding bedload transport and its characteristics provides insights into river morphology dynamics and aids in evaluating the impacts on boat navigation, hydropower production, ecological systems and aquatic habitat.
Acoustic Doppler Current Profilers (ADCPs) have been widely utilized for measuring bedload characteristics, with reported correlations between apparent bedload velocity, backscatter strength, and physically measured samples. To estimate bedload transport rates, three primary approaches are employed: (i) the kinematic model, which utilizes semi-empirical equations; (ii) multi-regression calibration tailored to different grain sizes; and (iii) machine learning techniques that utilize multiple features derived from ADCP outputs.
Among these, the kinematic model is the most commonly used and exists in two variations: one utilizing virtual particle velocity and the other relying on volume mass conservation. Although ADCP-estimated bedload transport rates are widely used, they are often accompanied by substantial uncertainty and error. Furthermore, the potential errors introduced by physical sampling methods and their impact on comparisons with ADCP-derived estimates have received little attention.
This study addresses these gaps by examining errors associated with both ADCP-based approaches and physical sampling techniques used to estimate bedload transport rates. It further evaluates how these errors interact under varying sediment transport conditions, offering insights into the reliability and limitations of ADCP measurements in comparison to traditional sampling methods.
The initial results indicate that the primary sources of error in the kinematic model stem from secondary parameters that are empirically derived, such as bedload concentration and active layer thickness. Furthermore, weak transport conditions are significantly overestimated by ADCP measurements, highlighting the limitations of the method under conditions of low-intensity and highly non-homogeneous transport.
Furthermore, a kinematic approach, which relies on the average virtual velocity of a monogranular loose bed, also raises questions regarding its reliability considering the ACDCP measuring capabilities, particularly when direct comparisons are made with physical samples. Additionally, errors associated with physical bedload sampling (e.g., bedload rate underestimation due to trap misalignment to sediment flux) are considered.
This study critically examines these methodological issues, with specific attention to the discrepancies that arise when comparing ADCP-based to traditional measurement techniques eventually providing a comprehensive evaluation of the uncertainties inherent in both.
How to cite: Conevski, S., Guerrero, M., Winterscheid, A., Tabesh, M., and Ruther, N.: Uncertainty discussions about the bedload transport rate estimation using ADCP data and comparison with the physical samples, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18313, https://doi.org/10.5194/egusphere-egu25-18313, 2025.
Submerged vanes are small, angled in-stream structures designed to redirect sediment by generating secondary flow circulations. In this study, we experimentally investigated the performance of an array of porous vanes in a laboratory flume, focusing on the lateral displacement of sediment induced by the vanes. Porous plates were chosen to minimize local scour and anchoring requirements while effectively redirecting flow, bedforms, and sediment laterally. The experiments were conducted in a 75 m long, 2.75 m wide open channel at the Saint Anthony Falls Laboratory, University of Minnesota. High-resolution 3D bed elevation data were continuously captured using a state-of-the-art submerged laser scanner. First, bedload transport rates in the streamwise direction were calculated based on bedform geometry and migration velocity, which were extracted from bathymetric data using a custom tracking method. These rates were then spatially distributed over the monitored area using a novel Eulerian-averaged grid-mapping approach to compute the two-dimensional, time-averaged bedload transport rates. This allowed us to propose a new methodology to estimate the lateral bedload transport using control volume theory and applying mass conservation. This quantitative assessment demonstrates that the vane array effectively controls lateral sediment transport distribution, suggesting that porous vanes could serve as a viable alternative for sediment management and river training. Furthermore, the proposed methodology for quantifying lateral sediment transport, combined with bedform tracking, could be broadly applied to other river engineering and geomorphological studies focused on sediment transport monitoring, thereby hopefully appealing to a broader research community.
How to cite: Musa, M., Guala, M., Lee, J., and Tseng, C.-Y.: Quantifying Lateral Bedload Transport Induced by Porous Vanes Using Submerged High-resolution Laser Scan, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7324, https://doi.org/10.5194/egusphere-egu25-7324, 2025.
The left-bank tributaries of the Aude River in the Minervois region exhibited a naturally braidding channel pattern during the Little Ice Age. However, beginning in the 17th century, they underwent significant modifications, including channelization, the construction of weirs, and straightening, which led to a simplification of channel morphology and a decline in the ecological quality of aquatic environments. The November 1999 flood event, alongside the implementation of European and national policies such as the Water Framework Directive (WFD) and the Law on Water and Aquatic Environments (LEMA), prompted public stakeholders to rapidly reassess river management strategies. This reconsideration spurred several initiatives aimed at decompartmentalizing rivers, gradually enabling the natural functioning of active zones, marked by fluvial metamorphosis, along with the reappearance of braiding and sinuosity.
This work investigates the adjustment trajectories of newly formed active channels and examines the influence of torrential dynamics within the watersheds on erosion, sediment transport, the regeneration of fluvial forms, and the formation of new habitats. The methodology combines various spatial (local vs. global) and temporal (ordinary hydrological events vs. floods events) scales, while also considering the ongoing impacts of climate change.
The primary objective of this research is to identify sediment sources within the studied watersheds to counteract channel incision. Two key hypotheses underpin this work: (i) the locally available sediment volume can mitigate incision, and (ii) the most suitable sediments for replenishment already exist within the watershed.
Since 2012, the deployment of pebbles equipped with RFID sensors, combined with LiDAR surveys, has facilitated the assessment of sediment dynamics and the effectiveness of restoration zones. The results indicate that these restoration zones are crucial for diminishing the energy of morphogenic floods and for sediment storage. However, during periods of ordinary hydrology, widespread channel incision remains a predominant issue.
In addressing this sediment deficit, the study explored various potential sediment sources, focusing on the volumes available in the former agricultural terraces of the Montagne Noire, alluvial deposits, and fossilized active channels. While alluvial deposits are readily mobilized, they do not suffice to compensate for the transported volumes. Agricultural terraces, although rich in sediment, present challenges related to vegetation cover. In contrast, former active channels offer significant potential, provided that measures are implemented to ensure their mobility.
This study underscores the vital role of ordinary floods in maintaining hydro-sedimentary balance and demonstrates that morphological restoration accelerates the return of braided channels. It also highlights the necessity of integrating systemic approaches at the watershed scale with targeted interventions to achieve sustainable outcomes.
Future research will examine the influence of riparian vegetation and the effects of widening active zones and reducing channel slopes on sediment trapping and deposition. These analyses will also incorporate climate projections and the anticipated occurrence of morphogenic floods, which are critical for the long-term success of restoration strategies.
How to cite: Brun, M., Arnaud-Fassetta, G., Corenblit, D., and Melun, G.: River restoration in the left-bank tributaries of the Aude River (southern France): Identifying sources of remobilizable alluvium for sustainable recharge of sediment-deficient river channels, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8640, https://doi.org/10.5194/egusphere-egu25-8640, 2025.
Metrics on hydromorphology are essential for evaluating river conditions under the Water Framework Directive (WFD) and provide a valuable tool for informing effective river restoration. Application of these tools, however, should include consideration of the sensitivity of the constituent indicators and as important step in assessing data quality and model robustness.
In this study systematic sensitivity analysis, using a machine learning-based framework, was performed on the new Morphological Quality Index (MQI) tool for Ireland (MQI v.2.0), obtained from the Irish Environmental Protection Agency (EPA). Analyses was conducted on a dataset from the River Suir catchment, which represents the full range of river types and pressures on hydromorphology in Ireland.
A Random Forest model was developed to model MQI using 16,838 combinations of the 14 key indicators. The model demonstrated exceptional predictive accuracy (R² > 0.98), highlighting the intricate relationships among indicators. Sensitivity was thereafter assessed by introducing adaptive noise (0.01σ to 3.5σ) to individual indicators, quantifying their influence on MQI predictions.
The results identified A13 (Historic Modifications), F3 (River-Corridor Connectivity), and A8 (Artificial River Course Changes) as the most sensitive indicators, demonstrating significant impacts on model performance metrics such as R² and RMSE. Riparian vegetation metrics, including F12 and F13, also emerged as sensitive indicators. The analysis revealed that the MQI tool is highly susceptible and sensitive to changes in these key indicators, suggesting that improving the quality of these indicators might enhance the overall reliability of MQI assessments. These insights into the relative importance of individual indicators in shaping hydromorphological assessments and potential implications for catchment management and restoration initiatives are discussed.
Keywords:
Hydromorphology, Morphological Quality Index (MQI), Indicators, Sensitivity Analysis, Random Forest
How to cite: Sajadi, P., Turner, J. N., O'Sullivan, J. J., Kelly-Quinn, M., Quintero, J., O’Hare, M., Casserly, C. M., Handibode, S., and Roche, W. K.: Data-Driven Sensitivity Analysis of River Hydromorphology Indicators Using Machine Learning, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19315, https://doi.org/10.5194/egusphere-egu25-19315, 2025.
Mapping river systems and their dynamics can enhance our understanding of the underlying geomorphic processes and their natural and anthropogenic drivers. Analyzing river morphological evolution, in particular, provides insights into historical, contemporary, and potential future river changes. This information can support river managers in identifying and prioritizing effective strategies for flood and geomorphic hazard management as well as for restoration programs. In Italy, the IRIDE project, funded by the Italian PNRR (Piano Nazionale Ripresa e Resilienza – “National Recovery and Resilience Plan”) and developed through a collaboration between the European Space Agency and the Presidency of the Council of Ministers of the Italian Republic, leverages available satellite constellations to establish an automated river monitoring system at national scale. This monitoring framework was designed using the Copernicus Sentinel-2 images (10 m resolution, 5 days revisit time) for medium-large rivers and will be further implemented with the upcoming IRIDE constellation (8 m resolution in multi-spectral bands + 3 m in panchromatic band, daily rivisit time). This contribution outlines the workflow developed in collaboration with the industry, showcasing key results that have supported various geomorphic analyses. The workflow involves: (1) generating a sequential structure of Disaggregated Geographic Objects (DGOs) to discretize rivers from upstream to downstream into ordered 500-meter-long units; (2) automating the generation of annual Active Channel (AC) masks—encompassing river water and sediment bars—using a global Convolutional Neural Network algorithm [1]; (3) performing monthly classifications of water, sediment, and vegetation within the annual AC mask via a data-driven algorithm tailored to the Italian territory; (4) analyzing the aggregated monthly classifications within the S2 archive (2017-2024) to develop indexes of geomorphic activities. The first results in the Po River network demonstrate that this monitoring system successufully capture planform mobility hotspots as well as episodic and progressive geomorphic change in each River reach. This systematic, nationally harmonized river observatory is unique and represents a pivotal step in using current satellite assets for wide-scale geomorphic analyses to support river management.
[1] Carbonneau, Patrice E., and Simone Bizzi. "Global mapping of river sediment bars." Earth Surface Processes and Landforms 49.1 (2024) - https://doi.org/10.1002/esp.5739 (2024)
How to cite: Bozzolan, E., Bizzi, S., Carbonneau, P., Surian, N., Brenna, A., Cecchetto, M., Teffetani, E., Vanzani, F., Matteligh, E., Doolaeghe, D., and Capito, L.: Implementing a national-scale River Monitoring with Sentinel 2 images , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17095, https://doi.org/10.5194/egusphere-egu25-17095, 2025.
Historical river management practices commonly involved river reach straightening (Wolf et al., 2021) where the planform variations of river location over some length were removed and replaced by a relatively straight downstream trend. Notably, river reach straightening generally also included a simplification of downstream river width variation such that re- constructed reaches were designed to convey specific flood magnitudes. Many decades later river management practices have changed to include river restoration and related efforts aimed at reviving river dynamics, associated functions and more recently resiliency in the face of climate change. Here, we offer a relatively straightforward approach in an attempt to meet these goals in some measure by reincorporating downstream river width variations into reaches that have been historically straightened.
There is growing recognition that downstream river width variations at the local scale of order the channel width are a basic attribute of rivers (e.g. Richards, 1976; DeAlmeida et al., 2012), and therefore likely correlate with a more dynamic riverscape characerized, for example, by spatial differences of the local flow velocity and depth. Ecological theory suggests that a more dynamic riverscape with environmental gradients can promote biological recovery (Wohl et al., 2015), thus providing a link between potential recovery and resilience, and the reincorporation of downstream width variations along straightened river reaches. We use scaling theory (Chartrand et al., 2018) and an analytical model (Lei et al., 2024) to develop an open-source basic design workflow which produces example river reach geometries with downstream width variations which are evaluated using an open-source morphodynamic model. The design workflow can be incorporated into broader approaches and procedures used to develop testable restoration design alternatives, and, importantly, the proposed workflow can also help the restoration community work towards an improved conceptualization of river restoration (Wohl et al., 2015) for circumstances where river-adjacent land is not available and restoration options are constrained.
References
1. Wolf, S. et al., Environ Sci Eur 33, 15 (2021), https://doi.org/10.1186/s12302-021-00460-8.
2. Richards, K. S., Geological Society of America Bulletin, 87, 883–883, 1976.
3. de Almeida, G. A. M. et al., Geophysical Research Letters, 39, L06407–L06407, https://doi.org/10.1029/2012GL051059, 2012.
4. Wohl, E.et al., Water Resources Research, 51, 5974–5997, https://doi.org/10.1002/2014WR016874, 2015.
5. Chartrand, S. M. et al., Journal of Geophysical Research: Earth Surface, 123, 2735–2766, https://doi.org/10.1029/2017JF004533, 2018.
6. Lei, Y. et al., Journal of Geophysical Research: Earth Surface, 129, e2024JF007641, https://doi.org/10.1029/2024JF007641, 2024.
How to cite: Chartrand, S.: Putting local wiggles back into rivers: a design workflow to reincorporate river width variations into historically straightened reaches, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20637, https://doi.org/10.5194/egusphere-egu25-20637, 2025.
Reservoir sedimentation poses significant challenges for water storage, including drinking water supply, irrigation, recreations, flood control, and other uses. However, accurate quantification of present and future reservoir sedimentation remains a considerable challenge. One of the main obstacles is the lack of repeated reservoir capacity surveys that cover the same spatial domains and employ consistent pre- and post-processing methods. Additionally, incorporating intricate nonlinear morphodynamics into sedimentation quantification is nontrivial. In this study, we analyze repeated bathymetric survey data from 62 reservoirs in Texas (USA) that utilize consistent processing methods, provided by Texas Water Development Board (TWDB). We also investigate spatio-temporal changes in remotely sensed suspended sediment concentration data (1984-2018), which allow to quantify temporal changes in incoming sediment flux to reservoirs and trap efficiency. Assuming a linear sedimentation rate, our results indicate that the capacity of the studied reservoirs in Texas is projected to decrease by 16% in 2100, relative to their maximum in 1994, when the most recent dam construction was completed. Furthermore, we observe an increase in suspended sediment concentration in East Texas, while other regions show a decrease in general. These spatial patterns correspond to observed changes in land cover, land usage, and streamflow. Our findings suggest that reservoirs in East Texas experience more rapid sedimentation due to increased sediment flux. We demonstrate the importance of accounting for such nonlinear sedimentation dynamics to improve long-term projections of reservoir sedimentation. These insights are essential for sustainable surface water management in the future.
How to cite: Lee, J., Chu, A., Hansen, C., Singh, D., Zhu, J., Musa, M., and Bhanja, S.: Decreasing water storage capacity in Texas due to reservoir sedimentation, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4773, https://doi.org/10.5194/egusphere-egu25-4773, 2025.
Dramatic environmental changes have altered the connectivity pattern of aquatic ecosystems and thus fish spawning habitats. Although connectivity processes in local riverine habitats are crucial for fish reproduction, existing connectivity simulation approaches do not allow for quantitatively describing the fine-scale connectivity structure driven by hydrogeomorphic variables. Here we proposed the fine-scale connectivity theory (FSCT) that tackled the challenge of nonlinearity issue in modeling asymmetric connectivity in water environments, aiming to clarify the mechanism of fine-scale functional connectivity structure on fish natural reproduction. The FSCT was applied to the spawning ground of the Chinese sturgeon, a critically endangered migratory fish of utmost concern in the Yangtze River, China. Results demonstrated that our method outperformed present connectivity models with an accuracy improvement of 25.1%. This study revealed a high correlation between the connectivity of spawning habitats and spawning capacity of the Chinese sturgeon, with a value of 0.947. Our findings revealed a significant decline in habitat connectivity within the Chinese sturgeon spawning ground, which was associated with the shift from an aggregated to a decentralized connectivity structure. This study can facilitate theoretical and technical support for habitat restoration and conservation efforts of endangered fish populations in dammed rivers.
How to cite: deng, Q., zhang, X., and fan, Z.: The fine-scale functional connectivity process in rivers influences the fish natural reproduction, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5315, https://doi.org/10.5194/egusphere-egu25-5315, 2025.
Deep scour holes in rivers, resulting from local flow variability, can pose a serious threat to nearby infrastructure, like pipelines, bridge pillars and the stability of embankments. Previous studies have revealed that in rivers with a stratified river bed, scour holes even evolve without the presence of an obstruction. Peak discharges and corresponding high flow velocities can break the hardly erodible top layer, exposing the underlying easy erodible bed materials to the flow. For instance, during the 2021 summer flood in the Maas River, the Netherlands, 15 scour holes, with a depth varying between 3 and 15 meters were formed within days. One of these scour holes threatened a ferry landing. Another scour hole uncovered a pipeline.
This research investigates the behaviour of scour holes to make well-considered choices to fill deep holes after their formation or to remain them open. We analysed the behaviour of eight different scour holes in the Rhine-Meuse Estuary and the River Waal over the period 2018-2024 using multibeam bed level measurements. We expressed the behaviour of a scour hole in terms of variations in area, volume and depth and tried to relate this to discharge variations. We can classify this behaviour into two categories: stable and dynamic. Stable scour holes, often located in sand bodies from former channel belts, show neglectable variations in area, volume, and depth within the monitored period. In contrast, dynamic scour holes respond to discharge fluctuations, expanding during peak flows and contracting during low discharges. On the long-term, over a period of more than five years, the dynamic scour holes shows a continuous growth or decrease in scour hole characteristics. This group of scour holes deforms and migrates which, at some point in time, may make them a threat to nearby infrastructure.
Our findings highlight the importance of understanding scour hole dynamics for effective river management, emphasizing that not all scour holes are in a stable state after their formation. While some recently formed scour holes pose immediately a threat to infrastructure, others may become a threat after repeated peak discharges that lead to significant growth in their dimensions.
How to cite: Oldenhof, M., Warmink, J., and Hulscher, S.: The Behaviour of Deep Scour Holes in Rivers: Stable States or Dynamic Fluctuations?, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8781, https://doi.org/10.5194/egusphere-egu25-8781, 2025.
Today, mining products are crucial to the development of various sectors of the economy. Although mining companies are trying to reduce their impact on the planet by aiming for green mining, huge waste rock deposits are placed around mining areas without specific guidelines to allow for ecological recovery. Waste rock deposits are usually formed to optimize the storage volume per area, with a stable terrace shape, according to the closure plan. Although this form is stable in the short term, the structures tend to erode through the development of gullies, driven by fluvial erosion, producing onsite (loss of vegetation and topsoil) and offsite (river pollution) effects. In order to reduce these impacts and leave a more sustainable landscape, geomorphic restoration of waste rock deposits have been undertaken at several sites, mainly in semi-arid environments where fluvial processes driven by rainfall events dominate. Here we present preliminary results of the first monitoring and comparison between geomorphic restoration waste rock deposit, with two main objectives: 1) compare the erosive response of the geomorphic and conventional site and 2) compare the advantages and disadvantages of the different surveying methods in a mining context.
The Svappavaara mining site is managed by LKAB and is located in northern Sweden. A 4-hectare geomorphic restoration started in 2022 and was completed in July 2023 after the addition of topsoil (till). The conventional terraced waste rock deposit was started in 2023 and completed in summer 2024. Surveys to assess geomorphic changes at both sites were carried out using photogrammetry with a DJI P1 camera, DJI L1 LiDAR camera and ground control points (GPS and total station). Comparable surveys within the geomorphic site were assessed in October 2023, June 2024 and October 2024 and will continue until spring 2026. Image errors that were obtained from 10 GCP ranged between 1.8 and 3 cm on the vertical axis. We use Geomorphic Change Detection software to compare the different digital elevation models generated by the surveys to determine erosion and deposition. As a control, a pond was constructed immediately downstream of the monitoring station to trap sediment and calculate the total export from each site.
Preliminary results from the surveys suggest initially high erosion rates at the geomorphic site with a declining trend. Erosion rates at the conventional site remain at an initially moderate level without a decreasing trend. Erosion at the geomorphic site followed expected patterns in channels and some rills on hillslopes. However, erosion at the conventional site exhibited the start of gully formation. We show how varying patterns of snowmelt and rainfall impact erosion patterns.
Errors in the vertical axis were 2.1 to 1.8 cm with GPS and total station, while RTK and no GCP accounted for a 3 cm error. LiDAR with RTK had an error of 5 cm. These results have implications for understanding the stabilization of new landforms and drainage systems after disturbance, and will provide important baseline data for mining companies planning to use geomorphic design rather than conventional waste dumps.
How to cite: Carrillo, R., Zapico, I., and Polvi, L.: Comparing ‘geomorphic design’ and conventional waste rock deposits at a mining site in northern Sweden., EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13775, https://doi.org/10.5194/egusphere-egu25-13775, 2025.
Posters on site: Wed, 30 Apr, 14:00–15:45 | Hall X3
Waterways can become underutilized transport potential because of riverbed degradation and reduction of low flows driven by the climate change. Long-term changes of river’s morphology are driven by sediment supply that is intensified during flood events and influenced by the flow dynamics and associated sediment transport. Morphodynamic changes directly impact riverine ecosystems, infrastructure, and flood risk management, and extended periods of low flows can pose critical obstacle for navigation, present considerable pressure on navigation management and reduce the transport efficiency. This study presents morphodynamic assessment of the Sava river’s section in Croatia identified as critical from the navigational perspective. Flow regime of the critical river reach is analysed using 1D HEC-RAS model. The aim of the paper is to evaluate the current condition of the river waterway, determine critical zones that can impede the navigation and define relevant parameters for long-term monitoring with purpose of fairway management. The 1D model is calibrated using the water levels and flow rates from the gauging stations and validated against the field ADCP data. Results show the satisfactory efficiency of the 1D model for interpretation of riverbed degradation and aggradation, while keeping the banks stabilized to reflect the constructed river training structures, mostly revetments, on both banks. The apparent one dimensionality of the flow enforced by the river training structures enable reliable use of the sediment transport equations over the period of few years, but the model is highly sensitive to the selection of the sediment transport equation.
How to cite: Gilja, G., Raštegorac, A., and Harasti, A.: Morphodynamic assessment of the Sava River’s critical navigational section, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1343, https://doi.org/10.5194/egusphere-egu25-1343, 2025.
This study aims to investigate the spatiotemporal variation of hydrodynamic forces around a sphere rigidly fixed to the bottom of a sloshing tank using numerical modeling and physical experiments. Firstly, an experimental study was carried out to generate reliable data for calibrating the numerical model, using a water tank with uniaxial freedom of movement constructed on a monorail operated by a computer-controlled step motor. During the experiments, the tank's movements were recorded using an accelerometer and ultrasonic sensors with a sampling frequency of 200 Hz. The water surface levels during sloshing were recorded with a video camera. The accelerometer and ultrasonic sensor data were used to impose the motion of the sloshing tank into a Reynolds-Averaged Navier-Stokes (RANS)-based numerical model. The video recordings, which comprised temporal fluctuations of the water surface, were used to calibrate the physcial model. Once the first numerical model was calibrated based on water surface level records using image processing methods, the second numerical model was constructed to accommodate a rigid spherical body with a 17 mm diameter connected to the bottom of the sloshing tank. The initial and boundary conditions used in the second numerical model were identical to those used in the physical model to measure the spatiotemporal fluctuations of the surrounding spherical body's kinematic and dynamic variables, respectively. The results demonstrated that sloshing motion substantially influences the boundary layer separation process around the sphere. It was also seen that the stage of the sloshing motion significantly impacts the temporal lag between the variables pressure, velocity and water surface level.
How to cite: Valyrakis, M., Aksel, M., and Yagci, O.: Hydrodynamic forcing on a sphere at the bottom of a sloshing tank: experiments and modeling, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19858, https://doi.org/10.5194/egusphere-egu25-19858, 2025.
Local scour next to hydraulic structures is a common occurrence resulting from the interaction of the local flow field with the erodible riverbed. Scour depth estimation is the basis for the hydraulic design of bridges, water intakes, flow diversion and similar structures as well as their scour countermeasures. The focus of this study is the experimental investigation of the variation of the flow field over the scour hole formed next to the bridge pier protected with riprap sloping structure. Clear water scour experiments were conducted in the hydraulic flume for as single flow rate close to the incipient motion condition. The experiment was run for 20 hours, with bathymetry and flow data measurement 2h, 6h, 10h, and 20h from the start of the experiment. During the experiment, the development of the scour hole has initiated deposition of the eroded material, evolving into bedforms over the downstream bed. The flow data was measured using the ADVP in the near-bed region on 15 points, arranged into the rectangular 5x3 grid, covering the entire scour hole and part of the surrounding riverbed. The measured data was analyzed through flow velocity, Reynolds shear stress, and turbulent kinetic energy pattern for different elevations over the riverbed. The results show that exists a relationship between the scour hole development and the Reynolds shear stress pattern, indicating the direction in which the eroded material is being transported from the scour hole.
Acknowledgements: This work has been funded in part by the Croatian Science Foundation under the project R3PEAT (UIP-2019-04-4046).
How to cite: Harasti, A., Gilja, G., Vuco, J., Boban, J., and Valyrakis, M.: Variation of the flow field over the scour hole, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1346, https://doi.org/10.5194/egusphere-egu25-1346, 2025.
Vessel movement at river confluences can erode bottom and bank sediments. While vessel-generated flows are known to resuspend significant amounts of sediment, limited data exist on the timing and mechanisms of this process. Suspended sediment concentration (SSC) responds to vessel-induced flow changes with a measurable phase lag and amplitude attenuation. This study quantitatively describes these phenomena using laboratory results from a 90° river confluence model, incorporating high-resolution SSC and three-dimensional velocity measurements. The results show that SSC consistently lags behind vessel-generated flows, with the lag increasing with height above the bed. Near-bed SSC typically equilibrates within one to two wave periods, whereas lag times near the water surface are longer due to persistent turbulence injection from vessel-induced underflow. A strong correlation (R² ~ 80%) was observed between SSC and turbulent kinetic energy (TKE), highlighting that SSC increases with rising TKE. The magnitude of sediment resuspension also depends on sediment availability, particularly at sediment bar formations. Sediment transport was predominantly directed toward the bankside, with occasional weak transport toward the channel center, influenced by wave groups and low-frequency drawdown timing. A wave-averaged suspended-load model was used to quantify the SSC lag relative to vessel-generated flows. Incorporating a decay rate of 0.06 s⁻¹ for antecedent waves significantly improved suspended-load predictions downstream of the confluence. Applying this decay rate across five additional sections reduced mean absolute error by 1.5 to 2 times compared to the unmodified model. The entrainment constant in the model varied slightly with water depth.
How to cite: Malasani, G. C., Chandra, V., and Kantharaj, M.: Navigation-Induced Suspended Resuspension at a River Confluence: Phase Lag and Amplitude Attenuation, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20511, https://doi.org/10.5194/egusphere-egu25-20511, 2025.
Globally, river ecosystems face severe declines, with freshwater vertebrate populations decreasing by 83% and many species now endangered. Only 14% of rivers in the UK are in good ecological condition, highlighting the urgency for restoration. Large wood (LW) has emerged as a key component in river restoration projects, enhancing geomorphic diversity, habitat heterogeneity, and biodiversity. Historically removed as "debris", its reintroduction is now essential for restoring natural river processes and creating diverse habitats for aquatic life. Despite the broad use of LW in river restoration, little is known about its effectiveness and suitability for different contexts. Therefore, this comprehensive review has been conducted to identify current knowledge gaps, examining the reliance expert judgment commonly used in restoration practice.
The review highlighted that most studies are concentrated in the US, the UK, and Australia. Temporal trend demonstrates a noticeable increase in studies starting around 2014. The types of LW structures employed in real-world river restoration project were also analysed. Surprisingly, more than 40% of the reviewed papers did not specify the exact configurations of the studied LW structures, referring only to "large wood" in general terms. When reported, the most frequently studied LW structures were LW jams, followed by single logs. However, a significant gap in the literature is the lack of detailed descriptions regarding the specific configurations of LW structures and how this affects restoration efforts. Field monitoring is also a widely used method, however, only two studies included long-term monitoring (10 to 20 years). The number of studies utilising numerical modelling is notably low, and the absence of artificial intelligence (AI) methodologies is also apparent. Also, this review revealed that the existing literature has a clear focus on lowland, low-energy river systems. Many of these rivers were classified within 2nd to 4th orders, indicating smaller to medium-sized tributaries.
The quantitative analysis of LW interventions highlights their diverse impacts. For example, LW dams, deflectors, and V-shaped structures can lead to a marked increase in pools, with coverage rising from 11% to 27% immediately after restoration, unlike single LW elements, which reported no statistically significant changes. Other effects are also evident: hydraulic retention time increased by up to 67.8%, whereas flow and morphological diversity increased by several orders of magnitude than pre-restoration conditions. These changes also saw a 35% rise in macroinvertebrate diversity and a tenfold increase in fish abundance, showcasing cascading ecological benefits. These findings underscore the multifaceted benefits of LW structures, particularly in promoting channel recovery, enhancing hydraulic and habitat diversity, and supporting habitat restoration over the long term.
How to cite: Nassaji Matin, G., Panici, D., Bennett, G., and Brazier, R.: Comprehensive Review of Large Wood in River Restoration Benefits, Risks and Future Directions, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2793, https://doi.org/10.5194/egusphere-egu25-2793, 2025.
Rivers play a crucial role in shaping landscapes through erosion, sediment transport and deposition. These processes, influenced by topography, geology, meteorology and land use, drive biological and chemical interactions with varying dynamics along the river course. Headwater streams, characterized by steep slopes and extreme weather conditions, are prone to erosion, making them significant sources of water and sediment that influence downstream geomorphology. Investigating historical and current changes in headwaters provides a detailed understanding of sedimentary dynamics and their relationship to physical characteristics and hydro-climatic regimes.
The study integrates historical and contemporary data analysis, focusing on four main objectives: (i) Historical and current hydrology tracking using official databases and field surveys; (ii) Conducting 3D analysis of historical geomorphic evolution through photogrammetric (Structure from Motion, SfM) reconstruction; (iii) Characterizing current morphodynamics using SfM techniques and unmanned aerial vehicles (UAV) for high-resolution seasonal monitoring; and (iv) Performing sedimentary and morphological analysis through traditional sediment characterization techniques. The studied headwater reaches are located in the Upper Aragón headwater, located in the Central Spanish Pyrenees.
By integrating multidisciplinary approaches, this study offers a comprehensive and precise framework to analyze sedimentary dynamics and fluvial morphodynamics. The innovative, rapid data collection procedure provides seasonal information, advancing our understating of river ecosystem evolution.
Preliminary results from historical reconstruction indicate a stabilization of streamflow over the past century, potentially driven by widespread forestation and land abandonment. These phenomena reduce erosion and sedimentary incomes, reducing morphologic diversity. Additionally, the observations in current morphodynamics confirms the methodology’s success in terms of precision, accuracy and speed, delivering high-quality data while reducing survey effort.
Acknowledgments: This work is funded by the European Research Council (ERC) by Starting Grant program from Horizon Europe 2021 under REA grant agreement number 101039181 – SED@HEAD. Authors also thanks Ebro River Basin authority for the provided data.
How to cite: Martín-Rodríguez, F. J., Llena, M., and Juez, C.: Morphodynamic analysis of diverse headwater reaches using remote sensing and historical reconstruction., EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8029, https://doi.org/10.5194/egusphere-egu25-8029, 2025.
Flow and sediment regimes are key to aquatic and floodplain habitats. Natural hydro-morphological processes are essential in creating such habitats and sustaining their ecological functions. River morphological changes are known to influence aquatic species by affecting availability and accessibility of habitats, energy expenditure, and behaviour. Climate change and human activities, for example damming and channelization, have altered these regimes, intensifying flooding and droughts and causing sediment starvation issues in these river systems. Sediment starvation has led to river narrowing and disconnection from floodplains, reducing habitat heterogeneity and consequently causing a loss of freshwater biodiversity. River restorations such as river widenings have recently been proposed to favour morphological processes and restore physical heterogeneity.
The morphological trajectories of river widenings depend on the level of sediment supply. Although some evidence supports the role of sediment supply in the evolution of widening morphologies, the linkage to fish habitat remains poorly understood. Therefore, we explored the following research questions: (i) What trade-offs exist among sediment supply, flow discharge, and habitat availability in river widenings? (ii) What morphological processes are associated with habitat dynamics, and how do these processes vary under different sediment supply levels? (iii) How can flood events alter these relationships?
Starting from experimental widening morphologies formed under various sediment supply levels and hydraulic conditions, we delineated the habitat availability of brown trout (Salmo trutta) under multiple discharge conditions using 2D hydrodynamic models and habitat suitability curves. We analyzed the habitat change and stability spatially between the evolution phases of the widening morphologies and investigated closely the underlying morphodynamic processes driving these habitat dynamics.
Our results reveal that widening morphologies formed with near-natural sediment supply showed a significant increase in habitat availability at all discharge conditions—especially drought and flood discharges—compared to the initial channelized state. Notably, the flood event further enhanced habitat availability at low flow conditions in these scenarios. Conversely, widening morphologies with reduced sediment supply did not show an improvement in habitat quantity during the widening formation phase or after a flood event. Furthermore, sediment supply levels clearly influenced the morphological processes responsible for habitat loss, gain, and persistence. This study advances our understanding of riverscapes by disentangling the role of sediment supply and flood events on fish habitat dynamics. Ultimately, these insights can guide us toward more effective restoration practices that promote resilient river ecosystems.
How to cite: Awadallah, M. O. M., Caponi, F., Vetsch, D. F., Boes, R. M., and Vanzo, D.: The role of sediment supply on fish habitat dynamics in river widenings, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8420, https://doi.org/10.5194/egusphere-egu25-8420, 2025.
Rivers and their floodplains in drylands provide critical ecosystem services, support biodiversity, and serve as hotspots for biomass production. Riverscapes are characterized by biogeomorphic succession trajectories, which depend on periodic flood disturbances. Studying undisturbed free-flowing rivers, which are increasingly rare and globally threatened, enhances our understanding of natural river behavior and can inform restoration and management of regulated systems. Key threats affecting an increasing number of rivers worldwide are the fragmentation of longitudinal connectivity due to dams, reduced lateral connectivity from flood protection measures such as dykes and the withdrawal of water for irrigation. This raises the question how rivers and their floodplains naturally maintain resilience over time and space and how they might respond to anthropogenic modifications as well as climate-induced changes in hydrologic connectivity and water availability.
Our research assesses the role of hydrologic connectivity in distinct phases of the fluvial biogeomorphic succession concept, which describes the interrelationship between hydrogeomorphic and vegetation dynamics and how they change over time. Interpreting the different biogeomorphic succession stages through the lens of ecosystem resilience is a promising approach towards quantifying resilience. To address the lack of long-term, large-scale monitoring, we utilized satellite time series analysis complemented by field data. We conducted remote sensing analysis at the river corridor scale, integrating digital geomorphometry and Sentinel-2 imagery for detailed habitat type mapping. Landsat time series analysis, using the LandTrendr segmentation algorithm, provided insights into the spatio-temporal dynamics of vegetation as well as hydromorphology and thus the functional channel-floodplain connectivity. Field data collected from 44 floodplain forest plots along the Naryn River in Kyrgyzstan across topographic gradients complemented the remote sensing-derived findings with detailed ecological information and provided insights into the vertical dimension of hydrologic connectivity.
The results show a significant influence of the lateral and vertical distance on the vegetation development over time and space as well as the species composition and density. These findings underscore the importance of lateral and vertical hydrological connectivity for semi-arid floodplain ecosystem succession. Interpreting these findings using the ecological resilience framework, we applied the ball-and-cup model across spatial and temporal scales, from individual river elements to entire river corridors. Notably, the biogeomorphic stage emerged as a critical switching point in the succession trajectory. These findings emphasize the importance of maintaining small units and the vertical connectivity for reach scale resilience and therefore have implications for the design of moving targets for the process-based conservation and restoration of rivers.
How to cite: Lauermann, M., Heckmann, T., Eichel, J., Poeppl, R., Egger, G., and Betz, F.: Assessing the importance of channel-floodplain connectivity for the resilience of floodplain ecosystem trajectories, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12339, https://doi.org/10.5194/egusphere-egu25-12339, 2025.
Large wood (LW) plays a fundamental role in maintaining the health and functionality of river ecosystems. LW influences hydrodynamics by altering flow patterns, contributes to sediment transport processes by trapping and redistributing sediment, and shapes diverse river channel forms. Moreover, LW enhances habitat complexity and diversity, sustaining biodiversity. Understanding and accurately quantifying LW storage is vital for a range of river management activities, including designing effective habitat restoration projects and implementing flood mitigation strategies. However, traditional field surveys and manual analysis of aerial imagery are labour-intensive, time-consuming, and limited in spatial and temporal scope. Advancing tools and techniques for LW quantification is therefore critical to enabling more efficient and widespread integration of wood into river restoration efforts.
This study introduces a fully automated method integrating high-resolution drone imagery and advanced machine learning algorithms to detect and quantify instream LW. Leveraging convolutional neural networks (CNNs), we trained a YOLOv10 model for wood detection and a YOLOv8 model for wood segmentation using datasets from eight rivers in the Swiss Alps and Argentinean Andes. An independent dataset from the Avançon de Nant River in Switzerland was used for method validation, ensuring the robustness and generalizability of the approach.
Our detection model achieved a 90\% accuracy in wood volume estimation and identified 97\% of wood pieces in the largest size bracket at a 0.3 confidence threshold, demonstrating high detection reliability. The segmentation model reached a mean Average Precision (mAP) of 70\%, effectively distinguishing wood pixels from background pixels despite slight underestimations in wood diameters for short and wide pieces. By automating both detection and volume estimation, our method addresses the limitations of traditional field-based approaches and significantly reduces human effort and potential for error.
The approach effectively detected wood across different environmental conditions, although challenges such as differentiating wood from similar-coloured substrates and accounting for partially submerged pieces remain. Expanding the training dataset to include more diverse environmental scenarios could enhance model accuracy and reliability.
This scalable and efficient method has substantial implications for monitoring river wood dynamics over large spatial and temporal scales. It provides a powerful and easy tool for scientists, conservationists, and river managers to understand wood storage better, improve habitat restoration efforts, and implement more informed flood risk management practices. Integrating UAV technology and machine learning significantly advances fluvial geomorphology studies, enabling consistent data collection in complex natural environments and informing sustainable management strategies.
How to cite: Aarnink, J., Consoli, G., Finch, B., O'Callaghan, M., Pascal, I., Wiesmann, S., and Ruiz-Villanueva, V.: Automatic Quantification of Instream Large Wood Storage Combining Machine Learning and High-Resolution Aerial Imagery, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10295, https://doi.org/10.5194/egusphere-egu25-10295, 2025.
How to analyse fluvial systems with successive interruption elements? The sediment transport dynamics of bedload in non-perennial fluvial systems influenced by various anthropogenic structures have significant potential to experience diverse interferences. Based on this premise, the present study utilises the concept of landscape connectivity, focusing on its structural aspect, to analyse the physical coupling of landscape sections, which becomes more evident in semi-arid fluvial systems with episodic behaviour.This view looks at places that help a lot with a certain outlet using the idea of Effective Catchment Area. This way helps to know watershed behavior by looking at flow events in the channel and the keeping or stopping capacity of the basins. The area chosen for this study is the Riacho Grande watershed, which comes from the lower Piancó River. The basin has water crossings, big dams, and simple dams put here and there throughout its size. The methods used are desk activities using remote sensing tools to find and sort the kinds of human-made structures, then field activities that helped check and grasp the impacts of each type of structure. The findings indicate the extent to which many dams, constructed haphazardly and without any government or water management supervision, extend from the headwater regions to areas near where the main channel of the Piancó River confluences with it. Because these structures interrupt flow, each segment downstream can momentarily function as a fresh source of sediment. In this regard, it raises considerations for long-term effects over decades and how the fluvial system will compensate in terms of either new sediment source areas or reduced capacity to transport sediment due to the constraint on its primary vector for transport (water).
How to cite: Castelo Branco, A. and Souza, J.: Restriction of Effective Catchment Area by Anthropogenic Elements in a Small Semi-Arid Basin: Preliminary Approaches., EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14748, https://doi.org/10.5194/egusphere-egu25-14748, 2025.
Modern floodplain ecosystems, despite being valuable resources, are increasingly threatened by urban and infrastructural development, particularly in their riparian areas. Therefore, monitoring floodplain ecosystems and processes is crucial for their protection and sustainable development. This study uses a topographic and geomorphic approach to carry out floodplain zonation along a 22 km urban stretch of the Narmada River in Central India. This reach is located about 20 km downstream of the Bergi dam- a large major anthropogenic intervention on the Narmada River. The Narmada River valley in the study reach is partly confined, and is marked by a litho-geomorphic complex region that includes ravine topography and dynamic fluvial systems. The river flows through a transition zone, the channel changes from a fractured bedrock riverbed (FBR) to a mixed or sediment-covered bedrock riverbed (SBR). We use satellite images (1965-2024; e.g., Corona, Landsat, ASTER, Sentinel, Planetscope), drone images, high resolution topographic data, field measurements for flood zonation. We employed a drone to capture inaccessible parts of the channel and floodplain, and Differential GPS (DGPS) for topographic measurements of the channel, banks, and floodplain. Acoustic Doppler Current Profilers (ADCP) was used to measure the bathymetry and flow velocity of the river. Anecdotal information about the past flood and associated inundation in the Narmada River was collected from the local population. The stretch experienced the largest flood event in the year 1991 as all spillway gates were opened to enable downstream movement of floodwater. Based on the geomorphic and topographic analysis, we demarcate and validate flood zones (No Go Zone, Regulatory Zone, Warning Zone). These zones exhibit a good match with flood extent attained historically by Narmada River. However, minor mismatches are noted, in places. We observed, through mapping and surveys, that the anthropogenic modifications have altered the geometry, slopes, sediment supply, riverbank heights, riparian vegetation, floodplain land use, bank stability, and natural flow patterns. Ex post facto analysis highlights those alterations due to the construction of the Bergi dam, rapid urbanization, infrastructure developments, and activities like agriculture, riverbed mining, and quarrying leading to anthropogenic pressure on the Narmada riverscape. These activities cause several disturbances in the channel and floodplain domains, for example, the agriculture activities disrupt the banks and gullies due to removal of riparian vegetation- a key factor for bank stability. We propose strategies for restoring natural flood pulses, stabilizing riverbanks, and improving flood risk management through measures that protect the riparian vegetation, bank gullies; as well as the implementation of an effective flood zonation policy. This study emphasizes the importance of geomorphic and topographic mapping and analysis for adapting effective restoration strategies in river management in order to manage and counteract anthropogenic pressures in the context of a part of the Narmada River in central India.
Keywords: Floodplain zonation, Geomorphic analysis, Anthropogenic interventions, Urban reach, Narmada River
How to cite: Kumar, V., Gaurav, K., and Tandon, S. K.: A geomorphic approach for floodplain zonation in an anthropogenically impacted reach of the Narmada River, Central India, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12020, https://doi.org/10.5194/egusphere-egu25-12020, 2025.
DANSER aims at addressing the urgent need for sustainable sediment management solutions at the river basin scale, focusing on the Danube River-Black Sea system. Foci are demonstration of multidisciplinary innovative and holistic solutions and developing deeper insights into the sediment status and cause-effect relationships (e.g. via spatiotemporal mapping of natural and anthropogenic fluvial processes, sediment transport modelling, sediment dating, 3D historical reconstruction, river processes forecast simulations, sediment budget analysis, connectivity modelling and interventions, stakeholder-engaged sediment parametric evaluation and co-management, interlinkages with biodiversity (patterns), water quality and climate change effects. This EU-funded (HORIZON-MISS-Danube & Black Sea Lighthouse) project seeks to restore sediment balance, improve sediment flow and quality together with EU- and other international stakeholders (existing bodies, digital platforms, events and know-how).
In an ample coverage throughout 3 DEMO (incl. 13 pilot) sites, 7 sibling locations, and 6 associated regions (AR), the DANSER approach will develop, validate, and promote key active and passive measures to mitigate human interference in the sediment flow, related biodiversity and ecological aspects and possibly recover the sediment balance and quality in critical stretches of the basin. In this poster presentation, we aim to provide an overview of the strategies and actions that are foreseen for the Upper Danube region, specifically in DEMO area 1 located in Lower Austria.
This research acknowledges support from the EU Projects HEU DANSER (grant agreement No 101157942), H2020 MERLIN (grant agreement No 101036337), HEU Danube4all (grant agreement No 101093985) i-CONN’ H 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement number 859937. Furthermore, the Austrian Federal Ministry for Digital and Economic Affairs and the Christian Doppler Research Association supported the work via the Christian Doppler Laboratory for Meta Ecosystem Dynamics in Riverine Landscapes (CD Laboratory MERI).
How to cite: Pöppl, R., Wagreich, M., Hein, T., Lang, A., Hohensinner, S., Hatzenbühler, D., Kowal, J., Recinos, S., Schwarz, U., Sandberger, J., Schneeweihs, S., and Klasz, G.: DANube SEdiment Restoration (DANSER): Towards deployment and upscaling of sustainable sediment management across the Danube River basin (The Upper Danube case), EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17336, https://doi.org/10.5194/egusphere-egu25-17336, 2025.
River woodlands can play a critical role in supporting healthy and biodiverse riverscapes, providing essential ecosystem services such as flood mitigation, drought resilience, carbon storage, and biodiversity. In Scotland, 50% of national riparian length is designated as degraded, which underscores the urgency of restoring and conserving river woodlands. These ecosystems are pivotal in addressing the twin crises of biodiversity loss and climate change while supporting local resilience and livelihoods. However, the creation and conservation of such healthy and resilient river systems through enhanced riparian and floodplain management with woodlands in Scotland is held back by lack of evidence and complex trade-offs of benefits for multiple stakeholders.
This project aimed to address these challenges by working with diverse stakeholders—including restoration practitioners, businesses, policymakers, and researchers—across Scotland to (1) identify evidence gaps across key benefit areas including flood and drought mitigation, addressing water and air pollution, carbon storage, biodiversity, food and biomass production and utilisation, and health, wellbeing, heritage and community involvement (2) appraise scientific evidence and stakeholder perceptions for these key benefit areas and (3) and uncover evidence needs and other barriers to river woodland restoration practice.
Through a literature review and engagement with 115 stakeholders via surveys, workshops, interviews, and focus groups, we identified key gaps in knowledge, barriers and opportunities for progress. Our findings highlighted a need to:
- Integrate the quantification of the diverse benefits of river woodlands to optimise restoration designs and avoid unintended consequences.
- Have robust spatial baseline data on water quality and biodiversity for planning, while long-term pre- and post- intervention monitoring is critical for evaluating restoration outcomes.
- Acknowledge the role of place and scale (both in space and time), and thereby transferability of benefits, especially as data gaps persist for large-scale effects like downstream flood mitigation.
- Address challenges posed by grazing pressures, fragmented policy frameworks, limited financial incentives, and integration with agricultural systems that hinder large-scale implementation.
- Improve governmental targets for river woodland coverage and cross-sector collaboration to advance multifunctional river woodland landscapes.
- Build on the new stakeholder network created for improved alignment and efficient communication between stakeholder needs and research focus.
This project brought together a comprehensive understanding of diverse stakeholders' perceptions and priorities regarding river woodland restoration. It has provided a step-change towards the realisation of river woodland restoration by developing a new research agenda and setting out recommended pathways to address these and other barriers. Key pathways identified include developing integrated monitoring strategies, leveraging citizen science, and fostering engagement and communication to align efforts across sectors. Our multi-disciplinary approach provides a successful method that could be applied to support various other environmental restoration efforts that deliver long-term ecosystem, social and economic benefits.
How to cite: Rostan, J., Geris, J., Adams, K., Cooksley, S., Marshall, K., Wartmann, F., Waylen, K., and Wilkinson, M.: Aligning research status with stakeholder challenges and evidence needs for supporting river woodland restoration , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19594, https://doi.org/10.5194/egusphere-egu25-19594, 2025.
We experimentally investigated the effect of particle shape on saltation over a smooth bed. The particle shapes considered included spheres, ellipsoids, ellipsoidal cylinders, and prisms, all having the same weight and nominal diameter. The Corey’s shape factor, varied from 0.2 (deformed prism) to 1 (sphere). We studied its effects on several Lagrangian indicators. The probability distribution function (pdf) of the streamwise velocity u transitions from Gaussian-like (SF=1) to gamma-like as the shape factor decreases. Specifically, the mean and variance of u increase and decrease, respectively, with increasing shape factor. The pdf of the transversal velocity v remains Gaussian-like, with zero mean, and its variance shows a negative correlation with the shape factor. The autocorrelation function of u is independent of the shape factor, with an average integral time scale of 0.5 s. In contrast, the autocorrelation function of v depends on the shape factor. We also computed the streamwise and transversal mean square displacements. In the streamwise direction, the behaviour is consistently super-diffusive, with an exponent of 0.83 for t<1 s and 0.63 for larger times. In the transversal direction, diffusion is normal for t>1 s. At small time scales, the diffusion regime is normal for low shape factors and super-diffusive for high shape factors.
How to cite: Rebai, D.: Particle motion over a smooth bed: effect of shape, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-21936, https://doi.org/10.5194/egusphere-egu25-21936, 2025.
Posters virtual: Wed, 30 Apr, 14:00–15:45 | vPoster spot 2
EGU25-2380 | ECS | Posters virtual | VPS26
Siphon-Enhanced Micro-Hydroelectric System: Harnessing Elevated Flow Rates for Improved Power GenerationWed, 30 Apr, 14:00–15:45 (CEST) | vP2.12
How to cite: Gkogkis, K. and Valyrakis, M.: Siphon-Enhanced Micro-Hydroelectric System: Harnessing Elevated Flow Rates for Improved Power Generation, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2380, https://doi.org/10.5194/egusphere-egu25-2380, 2025.
EGU25-2558 | ECS | Posters virtual | VPS26
Harnessing Aerial Imaging Techniques to Monitor the Transport of Floating Macro-Plastics in Fluvial SystemsWed, 30 Apr, 14:00–15:45 (CEST) | vP2.13
This research explores the transport dynamics of floating macro-plastics in riverine environments using drones for monitoring. Controlled flume experiments were conducted to evaluate the roles of vegetation density and release position on the movement and retention of plastic debris. Aerial imagery (captured by a DJI Mini 3 drone) was analyzed to determine transport patterns, revealing that plastics released in central flow zones moved faster with lower retention, while those near densely vegetated riparian areas experienced slower transport and higher trapping rates.
The findings demonstrate drones’ effectiveness in monitoring plastic pollution, providing a practical alternative to traditional methods in areas difficult to access. These insights emphasize the critical role of riparian vegetation in influencing plastic movement and retention, offering opportunities to design interventions that target pollution hotspots [1,2]. The study highlights the promise of drone-based approaches in advancing our understanding of plastic transport processes and informs strategies to mitigate the environmental impacts of plastic waste. Future research could enhance these findings by integrating drone data with other monitoring systems and refining analytical techniques for natural environments.
References
[1] van Emmerik T, Roebroek CTJ, de Wit W, Krooshof E, van Zoelen C, Fujita Y, Bruinsma J, Treilles R, Kieu-Le TC, Elshafie A, Christensen ND, Biermann L, Hees J, Meijer LJJ (2023) Seasonal dynamics of riverine macroplastic pollution, Nature Water, 1, 51-58
[2] Valyrakis M, Gilja G, Liu D, Latessa G (2024) Transport of Floating Plastics through the Fluvial Vector: The Impact of Riparian Zones, Water, 16, 1098
How to cite: Kaloudis, G. and Valyrakis, M.: Harnessing Aerial Imaging Techniques to Monitor the Transport of Floating Macro-Plastics in Fluvial Systems, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2558, https://doi.org/10.5194/egusphere-egu25-2558, 2025.
EGU25-16062 | Posters virtual | VPS26
Leveraging Digital-Physical Integration for Enhanced Infrastructure ManagementWed, 30 Apr, 14:00–15:45 (CEST) | vP2.14
The built environment (BE) across various sectors faces significant challenges due to increasing deterioration, ageing infrastructure, extreme climatic conditions, rising urban populations, and limited financial resources [1]. Digital transformation offers the potential to revolutionize current practices for managing and sharing key information, improving decision-making processes and enabling more efficient and sustainable BE in the long term. However, despite recent advancements in technology, critical infrastructure systems within the BE continue to rely on traditional management approaches in terms of technology, organizational structure, and institutional frameworks. Consequently, they fail to fully leverage emerging technologies that could enable advanced resource and risk management through real-time data integration and enahnced analytical methods.
Adopting technologies associated with Infrastructure 4.0 (CI4.0) [2] can accelerate the digitalization of BE, with a particular focus on infrastructure systems. This study highlights the foundational elements of a next-generation BE designed to foster an interconnected and collaborative ecosystem focused on cities, infrastructure, and societies. Several case studies are explored, including large residential developments, transportation networks, and buildings, demonstrating the transformative potential of digitalization in delivering real-time information to stakeholders, thereby enhancing decision-making processes.
These efforts rely on the acquisition of real-time data from the environment to predict both current and future conditions of the BE. For instance, advanced microcontrollers are utilized to monitor the declining performance of ageing infrastructure over waterways and to measure flood levels in real-time. Datasets are processed on high-performance cloud-based systems, utilizing deep learning algorithms to forecast infrastructure conditions and climatic risks. In emergency scenarios, such as river overflows, flash floods, or infrastructure failures, the system generates timely alerts. Moreover, predictive models provide early warnings about infrastructure deterioration, enabling critical stakeholders to respond proactively and adapt societal operations accordingly.
References
[1] Michalis, P., Vintzileou, E. (2022). The Growing Infrastructure Crisis: The Challenge of Scour Risk Assessment and the Development of a New Sensing System. Infrastructures, 7(5), 68. https://doi.org/10.3390/infrastructures7050068
[2] Xu, Y., AlObaidi, K., Michalis, P. and Valyrakis, M. (2020). Monitoring the potential for bridge protections destabilization, using instrumented particles. Proceedings of the International Conference on Fluvial Hydraulics River Flow, Delft, The Netherlands, 7–10 July 2020; pp. 1-8. eBook ISBN 9781003110958.
How to cite: Michalis, P., Konstantinidis, F., Katika, T., Michalis, A., and Valyrakis, M.: Leveraging Digital-Physical Integration for Enhanced Infrastructure Management, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16062, https://doi.org/10.5194/egusphere-egu25-16062, 2025.
