Articles | Volume 8, issue 4
https://doi.org/10.5194/esurf-8-855-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/esurf-8-855-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
21 Oct 2020
Research article |
| 21 Oct 2020
| 21 Oct 2020
Experimental study of sediment supply control on step formation, evolution, and stability
Department of Geography, The University of British Columbia, 1984 West Mall, Vancouver, BC, V6T1Z2, Canada
Marwan A. Hassan
Department of Geography, The University of British Columbia, 1984 West Mall, Vancouver, BC, V6T1Z2, Canada
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Matteo Saletti, Peter Molnar, Marwan A. Hassan, and Paolo Burlando
Earth Surf. Dynam., 4, 549–566, https://doi.org/10.5194/esurf-4-549-2016, https://doi.org/10.5194/esurf-4-549-2016, 2016
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This study presents a new reduced-complexity model with few parameters linked to basic physical processes, which aims to reproduce the transport of sediment as bed load and the formation and stability of channel morphology in steep mountain streams. The model is able to simulate the formation and stability of steps, bed structures commonly encountered in steep channels, by assuming that their formation is due to intense sediment transport during high flows causing jamming of particles.
Shawn M. Chartrand, A. Mark Jellinek, Marwan A. Hassan, and Carles Ferrer-Boix
Earth Surf. Dynam., 11, 1–20, https://doi.org/10.5194/esurf-11-1-2023, https://doi.org/10.5194/esurf-11-1-2023, 2023
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Rivers with alternating patterns of shallow and deep flows are commonly observed where a river widens and then narrows, respectively. But what if width changes over time? We use a lab experiment to address this question and find it is possible to decrease and then increase river width at a specific location and observe that flows deepen and then shallow consistent with expectations. Our observations can inform river restoration and climate adaptation programs that emphasize river corridors.
Chendi Zhang, Yuncheng Xu, Marwan A. Hassan, Mengzhen Xu, and Pukang He
Earth Surf. Dynam., 10, 1253–1272, https://doi.org/10.5194/esurf-10-1253-2022, https://doi.org/10.5194/esurf-10-1253-2022, 2022
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Step-pool morphology is common in mountain streams. The geomorphic processes of step-pool features closely interact with hydraulic properties, which have limited access due to measurement difficulties. We established a combined approach using both physical experiments and numerical simulations to acquire detailed three-dimensional hydraulics for step-pool morphology, which improves the understanding of the links between hydraulics and morphology for a step-pool feature.
J. Kevin Pierce, Marwan A. Hassan, and Rui M. L. Ferreira
Earth Surf. Dynam., 10, 817–832, https://doi.org/10.5194/esurf-10-817-2022, https://doi.org/10.5194/esurf-10-817-2022, 2022
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We describe the flow of sediment in river channels by replacing the complicated details of the turbulent water with probability arguments. Our major conclusions are that (1) sediment transport can be phrased in terms of the movements of individual sediment grains, (2) transport rates in river channels are inherently uncertain, and (3) sediment transport in rivers is directly analogous to a number of phenomena which we understand relatively well, such as molecules moving in air.
Xingyu Chen, Marwan A. Hassan, and Xudong Fu
Earth Surf. Dynam., 10, 349–366, https://doi.org/10.5194/esurf-10-349-2022, https://doi.org/10.5194/esurf-10-349-2022, 2022
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We compiled a large image dataset containing more than 125 000 sediments and developed a model (GrainID) based on convolutional neural networks to measure individual grain size from images. The model was calibrated on flume and natural stream images covering a wide range of fluvial environments. The model showed high performance compared with other methods. Our model showed great potential for grain size measurements from a small patch of sediment in a flume to a watershed-scale drone survey.
Chenge An, Marwan A. Hassan, Carles Ferrer-Boix, and Xudong Fu
Earth Surf. Dynam., 9, 333–350, https://doi.org/10.5194/esurf-9-333-2021, https://doi.org/10.5194/esurf-9-333-2021, 2021
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Mountain rivers are characterized by fluctuations of water flow, including both flood and inter-flood low flow. Recently, increasing attention has been paid to how inter-flood low flow affects the sediment transport in subsequent floods. Here we present a series of flume experiments. Results show that the existence of inter-flood low flow can reduce the sediment transport at the beginning of the subsequent flood. However, such an effect is gradually erased with the increase of flow intensity.
Carina Helm, Marwan A. Hassan, and David Reid
Earth Surf. Dynam., 8, 913–929, https://doi.org/10.5194/esurf-8-913-2020, https://doi.org/10.5194/esurf-8-913-2020, 2020
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Forested, gravel-bed streams possess complex channel morphologies which are difficult to objectively characterize. This paper describes a novel technique using a remotely piloted aircraft (RPA) to characterize these systems below the forest canopy. The results demonstrate the accuracy and coverage of RPAs for objectively characterizing and classifying these systems relative to more traditional, time-consuming techniques that are generally used in these environments.
Tobias Müller and Marwan A. Hassan
Earth Surf. Dynam., 6, 1041–1057, https://doi.org/10.5194/esurf-6-1041-2018, https://doi.org/10.5194/esurf-6-1041-2018, 2018
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We used a numerical model to study how mountain streams adjust to series of sediment input events, e.g., landslides. We recreated flume experiments with similar scope and then expanded their parameter space, allowing us to find conditions under which the stream becomes overloaded with sediment. This occurs when the stream cannot evacuate a sediment input in the time between pulses. Our results can help to better understand the long-term adjustment of mountain streams to episodic sediment supply.
Matteo Saletti, Peter Molnar, Marwan A. Hassan, and Paolo Burlando
Earth Surf. Dynam., 4, 549–566, https://doi.org/10.5194/esurf-4-549-2016, https://doi.org/10.5194/esurf-4-549-2016, 2016
Short summary
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This study presents a new reduced-complexity model with few parameters linked to basic physical processes, which aims to reproduce the transport of sediment as bed load and the formation and stability of channel morphology in steep mountain streams. The model is able to simulate the formation and stability of steps, bed structures commonly encountered in steep channels, by assuming that their formation is due to intense sediment transport during high flows causing jamming of particles.
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Earth Surf. Dynam., 12, 11–34, https://doi.org/10.5194/esurf-12-11-2024, https://doi.org/10.5194/esurf-12-11-2024, 2024
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Byungho Kang, Rusty A. Feagin, Thomas Huff, and Orencio Durán Vinent
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Coastal flooding can cause significant damage to coastal ecosystems, infrastructure, and communities and is expected to increase in frequency with the acceleration of sea level rise. In order to respond to it, it is crucial to measure and model their frequency and intensity. Here, we show deep-learning techniques can be successfully used to automatically detect flooding events from complex coastal imagery, opening the way to real-time monitoring and data acquisition for model development.
Judith Y. Zomer, Bart Vermeulen, and Antonius J. F. Hoitink
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Matthew C. Morriss, Benjamin Lehmann, Benjamin Campforts, George Brencher, Brianna Rick, Leif S. Anderson, Alexander L. Handwerger, Irina Overeem, and Jeffrey Moore
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Christopher Tomsett and Julian Leyland
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Rabab Yassine, Ludovic Cassan, Hélène Roux, Olivier Frysou, and François Pérès
Earth Surf. Dynam., 11, 1199–1221, https://doi.org/10.5194/esurf-11-1199-2023, https://doi.org/10.5194/esurf-11-1199-2023, 2023
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Daisuke Harada and Shinji Egashira
Earth Surf. Dynam., 11, 1183–1197, https://doi.org/10.5194/esurf-11-1183-2023, https://doi.org/10.5194/esurf-11-1183-2023, 2023
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Hemanti Sharma and Todd A. Ehlers
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Eduardo Gomez-de la Peña, Giovanni Coco, Colin Whittaker, and Jennifer Montaño
Earth Surf. Dynam., 11, 1145–1160, https://doi.org/10.5194/esurf-11-1145-2023, https://doi.org/10.5194/esurf-11-1145-2023, 2023
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Christoph Rettinger, Mina Tabesh, Ulrich Rüde, Stefan Vollmer, and Roy M. Frings
Earth Surf. Dynam., 11, 1097–1115, https://doi.org/10.5194/esurf-11-1097-2023, https://doi.org/10.5194/esurf-11-1097-2023, 2023
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Packing models promise efficient and accurate porosity predictions of fluvial sediment deposits. In this study, three packing models were reviewed, calibrated, and validated. Only two of the models were able to handle the continuous and large grain size distributions typically encountered in rivers. We showed that an extension by a cohesion model is necessary and developed guidelines for successful predictions in different rivers.
Alexander A. Ermilov, Gergely Benkő, and Sándor Baranya
Earth Surf. Dynam., 11, 1061–1095, https://doi.org/10.5194/esurf-11-1061-2023, https://doi.org/10.5194/esurf-11-1061-2023, 2023
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A novel, artificial-intelligence-based riverbed sediment analysis methodology is introduced that uses underwater images to identify the characteristic sediment classes. The main novelties of the procedure are as follows: underwater images are used, the method enables continuous mapping of the riverbed along the measurement vessel’s route contrary to conventional techniques, the method is cost-efficient, and the method works without scaling.
Kelly M. Sanks, John B. Shaw, Samuel M. Zapp, José Silvestre, Ripul Dutt, and Kyle M. Straub
Earth Surf. Dynam., 11, 1035–1060, https://doi.org/10.5194/esurf-11-1035-2023, https://doi.org/10.5194/esurf-11-1035-2023, 2023
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River deltas encompass many depositional environments (like channels and wetlands) that interact to produce coastal environments that change through time. The processes leading to sedimentation in wetlands are often neglected from physical delta models. We show that wetland sedimentation constrains flow to the channels, changes sedimentation rates, and produces channels more akin to field-scale deltas. These results have implications for the management of these vulnerable coastal landscapes.
Katharina Wetterauer and Dirk Scherler
Earth Surf. Dynam., 11, 1013–1033, https://doi.org/10.5194/esurf-11-1013-2023, https://doi.org/10.5194/esurf-11-1013-2023, 2023
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In glacial landscapes, debris supply rates vary spatially and temporally. Rockwall erosion rates derived from cosmogenic 10Be concentrations in medial moraine debris at five Swiss glaciers around Pigne d'Arolla indicate an increase in erosion from the end of the Little Ice Age towards deglaciation but temporally more stable rates over the last ∼100 years. Rockwall erosion rates are higher where rockwalls are steep and north-facing, suggesting a potential slope and temperature control.
Sam Anderson, Nicole Gasparini, and Joel Johnson
Earth Surf. Dynam., 11, 995–1011, https://doi.org/10.5194/esurf-11-995-2023, https://doi.org/10.5194/esurf-11-995-2023, 2023
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We measured rock strength and amount of fracturing in the two different rock types, sandstones and carbonates, in Last Chance Canyon, New Mexico, USA. Where there is more carbonate bedrock, hills and channels steepen in Last Chance Canyon. This is because the carbonate-type bedrock tends to be more thickly bedded, is less fractured, and is stronger. The carbonate bedrock produces larger boulders than the sandstone bedrock, which can protect the more fractured sandstone bedrock from erosion.
Jens M. Turowski, Gunnar Pruß, Anne Voigtländer, Andreas Ludwig, Angela Landgraf, Florian Kober, and Audrey Bonnelye
Earth Surf. Dynam., 11, 979–994, https://doi.org/10.5194/esurf-11-979-2023, https://doi.org/10.5194/esurf-11-979-2023, 2023
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Rivers can cut into rocks, and their strength modulates the river's erosion rates. Yet, which properties of the rock control its response to erosive action is poorly understood. Here, we describe parallel experiments to measure rock erosion rates under fluvial impact erosion and the rock's geotechnical properties such as fracture strength, elasticity, and density. Erosion rates vary over a factor of a million between different rock types. We use the data to improve current theory.
Koji Ohata, Hajime Naruse, and Norihiro Izumi
Earth Surf. Dynam., 11, 961–977, https://doi.org/10.5194/esurf-11-961-2023, https://doi.org/10.5194/esurf-11-961-2023, 2023
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We investigated the influence of sediment transport modes on the formation of bedforms using theoretical analysis. The results of the theoretical analysis were verified with published data of plane beds obtained by fieldwork and laboratory experiments. We found that suspended sand particles can promote the formation of plane beds on a fine-grained bed, which suggests that the presence of suspended particles suppresses the development of dunes under submarine sediment-laden gravity currents.
Matan Ben-Asher, Florence Magnin, Sebastian Westermann, Josué Bock, Emmanuel Malet, Johan Berthet, Ludovic Ravanel, and Philip Deline
Earth Surf. Dynam., 11, 899–915, https://doi.org/10.5194/esurf-11-899-2023, https://doi.org/10.5194/esurf-11-899-2023, 2023
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Quantitative knowledge of water availability on high mountain rock slopes is very limited. We use a numerical model and field measurements to estimate the water balance at a steep rock wall site. We show that snowmelt is the main source of water at elevations >3600 m and that snowpack hydrology and sublimation are key factors. The new information presented here can be used to improve the understanding of thermal, hydrogeological, and mechanical processes on steep mountain rock slopes.
Jessica Droujko, Srividya Hariharan Sudha, Gabriel Singer, and Peter Molnar
Earth Surf. Dynam., 11, 881–897, https://doi.org/10.5194/esurf-11-881-2023, https://doi.org/10.5194/esurf-11-881-2023, 2023
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We combined data from satellite images with data measured from a kayak in order to understand the propagation of fine sediment in the Vjosa River. We were able to find some storm-activated and some permanent sources of sediment. We also estimated how much fine sediment is carried into the Adriatic Sea by the Vjosa River: approximately 2.5 Mt per year, which matches previous findings. With our work, we hope to show the potential of open-access satellite images.
Kate C. P. Leary, Leah Tevis, and Mark Schmeeckle
Earth Surf. Dynam., 11, 835–847, https://doi.org/10.5194/esurf-11-835-2023, https://doi.org/10.5194/esurf-11-835-2023, 2023
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Despite the importance of bedforms (e.g., ripples, dunes) to sediment transport, the details of sediment transport on a sub-bedform scale are poorly understood. This paper investigates sediment transport in the downstream and cross-stream directions over bedforms with straight crests. We find that the patterns of bedload transport are highly variable on the sub-bedform scale, which is important for our understanding of the evolution of bedforms with complex crest geometries.
Gabriele Barile, Marco Redolfi, and Marco Tubino
EGUsphere, https://doi.org/10.5194/egusphere-2023-1551, https://doi.org/10.5194/egusphere-2023-1551, 2023
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River bifurcations often show the closure of one branch (avulsion), whose causes are still poorly understood. Our model shows that when one branch stops transporting sediments, the other considerably erodes and captures much more flow, resulting in a self-sustaining process. This phenomenon intensifies when increasing the length of the branches, eventually leading to branch closure. This work may help to understand when avulsions occur, and thus to design sustainable river restoration projects.
Xuxu Wu, Jonathan Malarkey, Roberto Fernández, Jaco Baas, Ellen Pollard, and Daniel Parsons
EGUsphere, https://doi.org/10.5194/egusphere-2023-1375, https://doi.org/10.5194/egusphere-2023-1375, 2023
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The seabed can change its shape from flat to undulating, known as ripples; the change rate depends on whether the bed is composed of sticky mud. This study, based on experiments, shows a strong reduction in ripple size when the initial mud content over 10.6 %. This could help geologists better interpret the ancient sea conditions. We present a new model to predict ripple size by considering sticky mud. It should help engineers to describe the behavior of the seabed when sticky mud is present.
Paul A. Carling, John D. Jansen, Teng Su, Jane Lund Andersen, and Mads Faurschou Knudsen
Earth Surf. Dynam., 11, 817–833, https://doi.org/10.5194/esurf-11-817-2023, https://doi.org/10.5194/esurf-11-817-2023, 2023
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Many steep glaciated rock walls collapsed when the Ice Age ended. How ice supports a steep rock wall until the ice decays is poorly understood. A collapsed rock wall was surveyed in the field and numerically modelled. Cosmogenic exposure dates show it collapsed and became ice-free ca. 18 ka ago. The model showed that the rock wall failed very slowly because ice was buttressing the slope. Dating other collapsed rock walls can improve understanding of how and when the last Ice Age ended.
Paul A. Jarvis, Clement Narteau, Olivier Rozier, and Nathalie M. Vriend
Earth Surf. Dynam., 11, 803–815, https://doi.org/10.5194/esurf-11-803-2023, https://doi.org/10.5194/esurf-11-803-2023, 2023
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Sand dune migration velocity is inversely proportional to dune size. Consequently, smaller, faster dunes can collide with larger, slower downstream dunes. Such collisions can result in either coalescence or ejection, whereby the dunes exchange mass but remain separate. Our numerical simulations show that the outcome depends probabilistically on the dune size ratio, which we describe through an empirical function. Our numerical predictions compare favourably against experimental observations.
Paul Carling
EGUsphere, https://doi.org/10.5194/egusphere-2023-1621, https://doi.org/10.5194/egusphere-2023-1621, 2023
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Edge rounding in Shap granite glacial erratics is an irregular function of distance from the source outcrop in northern England, UK. Block shape is conservative, evolving according to block fracture mechanics ─ stochastic and silver ratio models ─ towards either of two attractor states. Progressive reduction in size occurs to blocks transported at the sole of the ice mass where the blocks are subject to the compressive and tensile forces of the ice acting against a bedrock or till surface.
Adrian Ringenbach, Peter Bebi, Perry Bartelt, Andreas Rigling, Marc Christen, Yves Bühler, Andreas Stoffel, and Andrin Caviezel
Earth Surf. Dynam., 11, 779–801, https://doi.org/10.5194/esurf-11-779-2023, https://doi.org/10.5194/esurf-11-779-2023, 2023
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Swiss researchers carried out repeated rockfall experiments with rocks up to human sizes in a steep mountain forest. This study focuses mainly on the effects of the rock shape and lying deadwood. In forested areas, cubic-shaped rocks showed a longer mean runout distance than platy-shaped rocks. Deadwood especially reduced the runouts of these cubic rocks. The findings enrich standard practices in modern rockfall hazard zoning assessments and strongly urge the incorporation of rock shape effects.
Colin K. Bloom, Corinne Singeisen, Timothy Stahl, Andrew Howell, and Chris Massey
Earth Surf. Dynam., 11, 757–778, https://doi.org/10.5194/esurf-11-757-2023, https://doi.org/10.5194/esurf-11-757-2023, 2023
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Earthquakes can cause damaging coastal cliff retreat, but we have a limited understanding of how these infrequent events influence multidecadal retreat. This makes hazard planning a challenge. In this study, we use historic aerial images to measure coastal cliff-top retreat at a site in New Zealand. We find that earthquakes account for close to half of multidecadal retreat at this site, and our results have helped us to develop tools for estimating the influence of earthquakes at other sites.
Rishitosh K. Sinha, Dwijesh Ray, Tjalling De Haas, Susan J. Conway, and Axel Noblet
Earth Surf. Dynam., 11, 713–730, https://doi.org/10.5194/esurf-11-713-2023, https://doi.org/10.5194/esurf-11-713-2023, 2023
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Our detailed investigation of Martian gullies formed in different substrates in 29 craters distributed between 30°–75° S latitude suggests that they can be differentiated from one another in terms of (1) morphology and length of alcoves and (2) mean gradient of the gully fans. The comparison between the Melton ratio, alcove length, and fan gradient of Martian and terrestrial gullies suggests that Martian gullies were likely formed by terrestrial debris-flow-like processes in the past.
Gary Parker, Chenge An, Michael P. Lamb, Marcelo H. Garcia, Elizabeth H. Dingle, and Jeremy G. Venditti
EGUsphere, https://doi.org/10.5194/egusphere-2023-1705, https://doi.org/10.5194/egusphere-2023-1705, 2023
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River morphology has traditionally been divided by the size 2 mm. We use dimensionless arguments to show that particles in the 1 – 5 mm range a) are the finest range not easily suspended by alluvial flood flows, b) are transported preferentially over coarser gravel, and c) within limits, are also transported preferentially over sand. We show how fluid viscosity mediates the special status of sediment in this range.
Christopher J. Skinner and Thomas J. Coulthard
Earth Surf. Dynam., 11, 695–711, https://doi.org/10.5194/esurf-11-695-2023, https://doi.org/10.5194/esurf-11-695-2023, 2023
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Landscape evolution models allow us to simulate the way the Earth's surface is shaped and help us to understand relevant processes, in turn helping us to manage landscapes better. The models typically represent the land surface using a grid of square cells of equal size, averaging heights in those squares. This study shows that the size chosen by the modeller for these grid cells is important, with larger sizes making sediment output events larger but less frequent.
Hossein Hosseiny, Claire C. Masteller, Jedidiah E. Dale, and Colin B. Phillips
Earth Surf. Dynam., 11, 681–693, https://doi.org/10.5194/esurf-11-681-2023, https://doi.org/10.5194/esurf-11-681-2023, 2023
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It is of great importance to engineers and geomorphologists to predict the rate of bed load in rivers. In this contribution, we used a large dataset of measured data and developed an artificial neural network (ANN), a machine learning algorithm, for bed load prediction. The ANN model predicted the bed load flux close to measured values and better than the ones obtained from four standard bed load models with varying degrees of complexity.
Ian Delaney, Leif Anderson, and Frédéric Herman
Earth Surf. Dynam., 11, 663–680, https://doi.org/10.5194/esurf-11-663-2023, https://doi.org/10.5194/esurf-11-663-2023, 2023
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This paper presents a two-dimensional subglacial sediment transport model that evolves a sediment layer in response to subglacial sediment transport conditions. The model captures sediment transport in supply- and transport-limited regimes across a glacier's bed and considers both the creation and transport of sediment. Model outputs show how the spatial distribution of sediment and water below a glacier can impact the glacier's discharge of sediment and erosion of bedrock.
Sam Y. J. Huang, Steven Y. J. Lai, Ajay B. Limaye, Brady Z. Foreman, and Chris Paola
Earth Surf. Dynam., 11, 615–632, https://doi.org/10.5194/esurf-11-615-2023, https://doi.org/10.5194/esurf-11-615-2023, 2023
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We use experiments and a model to study the effects of confinement width and the inflow-to-sediment discharge ratio on the evolution of submarine braided channels. We find that confinement width controls most of the morphological changes. These trends are consistent for submarine braided channels both with and without confinement width effects and similar to fluvial braided rivers. Furthermore, we built a model that can simulate the flow bifurcation and confluence of submarine braided channels.
Alice Lefebvre and Julia Cisneros
Earth Surf. Dynam., 11, 575–591, https://doi.org/10.5194/esurf-11-575-2023, https://doi.org/10.5194/esurf-11-575-2023, 2023
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Underwater dunes are found in various environments with strong hydrodynamics and sandy sediment. Using a numerical model, we investigated how the dune shape influences flow velocity and turbulence. We propose a classification with three types of dunes, depending on their mean lee side angles (low-angle dunes, intermediate-angle dunes and high-angle dunes). We discuss the implications of this classification on the interaction between dune morphology, flow and sediment transport.
Daniel Ciarletta, Jennifer Miselis, Julie Bernier, and Arnell Forde
EGUsphere, https://doi.org/10.5194/egusphere-2023-1307, https://doi.org/10.5194/egusphere-2023-1307, 2023
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We reconstructed the evolution of Fire Island, a barrier island in New York, USA, to identify drivers of landscape change. Results reveal Fire Island was once divided into multiple inlet-separated islands with distinct features. Later, inlets closed, and Fire Island’s landscape became more uniform as human activities intensified. The island is now less mobile and less likely to resist and recover from storm impacts and sea-level rise. This vulnerability may exist for other stabilized barriers.
Haggai Eyal, Moshe Armon, Yehouda Enzel, and Nadav G. Lensky
Earth Surf. Dynam., 11, 547–574, https://doi.org/10.5194/esurf-11-547-2023, https://doi.org/10.5194/esurf-11-547-2023, 2023
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Extracting paleoenvironmets from sedimentologic and geomorphic records is a main goal in Earth sciences. We study a chain of processes connecting causative Mediterranean cyclones, coeval floods, storm waves generated by mesoscale funneled wind, and coastal gravel transport. This causes northward dispersion of gravel along the modern Dead Sea coast, which has also persisted since the late Pleistocene, resulting in beach berms and fan deltas always being deposited north of channel mouths.
Rémi Bossis, Vincent Regard, and Sébastien Carretier
Earth Surf. Dynam., 11, 529–545, https://doi.org/10.5194/esurf-11-529-2023, https://doi.org/10.5194/esurf-11-529-2023, 2023
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This study presents a method to calculate the volume of rock eroded by the sea on volcanic islands, by reconstructing their pre-erosion shape and size. The method has been applied on Corvo Island (Azores). We show that before the island was eroded, it was roughly 8 km wide and 1 km high. The island has lost more than 6 km3 of rock and 80 % of its surface. We also show that the erosion of sea cliffs is mainly due to the moderate and most frequent waves.
Nicolas Steeb, Virginia Ruiz-Villanueva, Alexandre Badoux, Christian Rickli, Andrea Mini, Markus Stoffel, and Dieter Rickenmann
Earth Surf. Dynam., 11, 487–509, https://doi.org/10.5194/esurf-11-487-2023, https://doi.org/10.5194/esurf-11-487-2023, 2023
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Various models have been used in science and practice to estimate how much large wood (LW) can be supplied to rivers. This contribution reviews the existing models proposed in the last 35 years and compares two of the most recent spatially explicit models by applying them to 40 catchments in Switzerland. Differences in modelling results are discussed, and results are compared to available observations coming from a unique database.
Lindsay Marie Capito, Enrico Pandrin, Walter Bertoldi, Nicola Surian, and Simone Bizzi
EGUsphere, https://doi.org/10.5194/egusphere-2023-1186, https://doi.org/10.5194/egusphere-2023-1186, 2023
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We proposed that the pattern of erosion and deposition from repeat topographic surveys can be a proxy for path length in gravel-bed rivers. With laboratory and field data, we applied tools from signal processing to quantify this periodicity and used these path length estimates to calculate sediment transport using the morphological method. Our results highlight the potential to expand the use of the morphological method using only remotely sensed data as well as its limitations.
Shunsuke Oya, Fumitoshi Imaizumi, and Shoki Takayama
EGUsphere, https://doi.org/10.5194/egusphere-2023-1032, https://doi.org/10.5194/egusphere-2023-1032, 2023
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The monitoring of pore-water pressure in fully and partly debris flows was performed in Ohya landslide scar, central Japan. The pore-water pressure in some partly saturated flows highly exceeded the hydrostatic pressure. The depth gradient of the pore-water pressure in the lower part of the flow was generally higher than the upper part of the flow. We conclude that the flow type (fully or partly saturated flows) should be considered to estimate the pore-water pressure in debris flows.
Ci-Jian Yang, Pei-Hao Chen, Erica D. Erlanger, Jens M. Turowski, Sen Xu, Tse-Yang Teng, Jiun-Chuan Lin, and Jr-Chuang Huang
Earth Surf. Dynam., 11, 475–486, https://doi.org/10.5194/esurf-11-475-2023, https://doi.org/10.5194/esurf-11-475-2023, 2023
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Observations of the interaction between extreme physical erosion and chemical weathering dynamics are limited. We presented major elements of stream water in the badland catchment at 3 h intervals during a 3 d typhoon. The excess sodium in the evaporite deposits causes material dispersion through deflocculation, which enhances the suspended sediment flux. Moreover, we observed a shift from predominantly evaporite weathering at peak precipitation to silicate weathering at peak discharge.
Slim Mtibaa and Haruka Tsunetaka
Earth Surf. Dynam., 11, 461–474, https://doi.org/10.5194/esurf-11-461-2023, https://doi.org/10.5194/esurf-11-461-2023, 2023
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We explore the relation between the spatial patterns of rainfall return levels for various timespans (1–72 h) and landslide density during a rainfall event that triggered widespread landslides. We found that landslide density increases with increased rainfall return levels for the various examined timespans. Accordingly, we conclude that whether rainfall intensities reached exceptional return levels for a wide time range is a key determinant of the spatial distribution of landslides.
Jennifer R. Shadrick, Dylan H. Rood, Martin D. Hurst, Matthew D. Piggott, Klaus M. Wilcken, and Alexander J. Seal
Earth Surf. Dynam., 11, 429–450, https://doi.org/10.5194/esurf-11-429-2023, https://doi.org/10.5194/esurf-11-429-2023, 2023
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This study uses a coastal evolution model to interpret cosmogenic beryllium-10 concentrations and topographic data and, in turn, quantify long-term cliff retreat rates for four chalk sites on the south coast of England. By using a process-based model, clear distinctions between intertidal weathering rates have been recognised between chalk and sandstone rock coast sites, advocating the use of process-based models to interpret the long-term behaviour of rock coasts.
Jayaram Hariharan, Kyle Wright, Andrew Moodie, Nelson Tull, and Paola Passalacqua
Earth Surf. Dynam., 11, 405–427, https://doi.org/10.5194/esurf-11-405-2023, https://doi.org/10.5194/esurf-11-405-2023, 2023
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We simulate the transport of material through numerically simulated river deltas under natural and human-modified (embankment construction and channel dredging) scenarios to understand their impacts on material transport. Human modifications reduce the total area visited by passive particles and alter the amount of time spent within the delta relative to natural conditions. This work can help us understand how future construction may impact land building or ecosystem restoration projects.
Livia Piermattei, Tobias Heckmann, Sarah Betz-Nutz, Moritz Altmann, Jakob Rom, Fabian Fleischer, Manuel Stark, Florian Haas, Camillo Ressl, Michael H. Wimmer, Norbert Pfeifer, and Michael Becht
Earth Surf. Dynam., 11, 383–403, https://doi.org/10.5194/esurf-11-383-2023, https://doi.org/10.5194/esurf-11-383-2023, 2023
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Alpine rivers have experienced strong changes over the last century. In the present study, we explore the potential of historical multi-temporal elevation models, combined with recent topographic data, to quantify 66 years (from 1953 to 2019) of river changes in the glacier forefield of an Alpine catchment. Thereby, we quantify the changes in the river form as well as the related sediment erosion and deposition.
Amande Roque-Bernard, Antoine Lucas, Eric Gayer, Pascal Allemand, Céline Dessert, and Eric Lajeunesse
Earth Surf. Dynam., 11, 363–381, https://doi.org/10.5194/esurf-11-363-2023, https://doi.org/10.5194/esurf-11-363-2023, 2023
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Sediment transport in rivers is an important matter in Earth surface dynamics. We offer a new framework of understanding of the suspended sediment transport through observatory chronicles and a simple model that is able to catch the behavior during a flood event as well as time series in a steep river catchment. We validate our approach in both tropical and alpine environments, which also offers additional estimates of the size of the suspended sediment.
Andrea Gasparotto, Stephen E. Darby, Julian Leyland, and Paul A. Carling
Earth Surf. Dynam., 11, 343–361, https://doi.org/10.5194/esurf-11-343-2023, https://doi.org/10.5194/esurf-11-343-2023, 2023
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In this study the processes leading to bank failures in the hypertidal Severn Estuary are studied employing numerical models and field observations. Results highlight that the periodic fluctuations in water levels drive an imbalance in the resisting (hydrostatic pressure) versus driving (pore water pressure) forces causing a frequent oscillation of bank stability between stable (at high tide) and unstable states (at low tide) both on semidiurnal bases and in the spring–neap transition.
Emma Lodes, Dirk Scherler, Renee van Dongen, and Hella Wittmann
Earth Surf. Dynam., 11, 305–324, https://doi.org/10.5194/esurf-11-305-2023, https://doi.org/10.5194/esurf-11-305-2023, 2023
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We explored the ways that boulders and bedrock affect the shapes of hills and valleys by testing how quickly they erode compared to soil. We found that bedrock and boulders mostly erode more slowly than soil and predict that fracture patterns affect where they exist. We also found that streams generally follow fault orientations. Together, our data imply that fractures influence landscapes by weakening bedrock, causing it to erode faster and to eventually form a valley where a stream may flow.
Thomas O. Hoffmann, Yannik Baulig, Stefan Vollmer, Jan H. Blöthe, Karl Auerswald, and Peter Fiener
Earth Surf. Dynam., 11, 287–303, https://doi.org/10.5194/esurf-11-287-2023, https://doi.org/10.5194/esurf-11-287-2023, 2023
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We analyzed more than 440 000 measurements from suspended sediment monitoring to show that suspended sediment concentration (SSC) in large rivers in Germany strongly declined by 50 % between 1990 and 2010. We argue that SSC is approaching the natural base level that was reached during the mid-Holocene. There is no simple explanation for this decline, but increased sediment retention in upstream headwaters is presumably the major reason for declining SSC in the large river channels studied.
Ngai-Ham Chan, Moritz Langer, Bennet Juhls, Tabea Rettelbach, Paul Overduin, Kimberly Huppert, and Jean Braun
Earth Surf. Dynam., 11, 259–285, https://doi.org/10.5194/esurf-11-259-2023, https://doi.org/10.5194/esurf-11-259-2023, 2023
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Arctic river deltas influence how nutrients and soil organic carbon, carried by sediments from the Arctic landscape, are retained or released into the Arctic Ocean. Under climate change, the deltas themselves and their ecosystems are becoming more vulnerable. We build upon previous models to reproduce for the first time an important feature ubiquitous to Arctic deltas and simulate its future under climate warming. This can impact the future of Arctic deltas and the carbon release they moderate.
Byungho Kang, Rusty A. Feagin, Thomas Huff, and Orencio Durán Vinent
EGUsphere, https://doi.org/10.5194/egusphere-2023-238, https://doi.org/10.5194/egusphere-2023-238, 2023
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We provide a detailed characterization of the frequency, intensity and duration of flooding events at a site along the Texas coast that demonstrates the suitability of relatively simple wave run-up models to estimate the frequency and intensity of coastal flooding. Our results validate and expands the first probabilistic model of coastal flooding driven by wave run-up, which can then be used in coastal risk management and coastal response to sea level rise.
Cited articles
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Chartrand, S. M., Jellinek, M., Whiting, P. J., and Stamm, J.: Geometric scaling of step-pools in mountain streams: Observations and implications, Geomorphology, 129, 141–151, https://doi.org/10.1016/j.geomorph.2011.01.020, 2011. a, b
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Hassan, M. A., Saletti, M., Zhang, C., Ferrer-Boix, C., Johnson, J. P. L., Mueller, T., and von Flotow, C.: Co-evolution of coarse grain structuring and bed roughness in response to episodic sediment supply in an experimental aggrading channel, Earth Surf. Proc. Land., 45, 948–961, https://doi.org/10.1002/esp.4788, 2020. a, b
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Zimmermann, A. E., Church, M., and Hassan, M. A.: Video-based gravel transport measurements with a flume mounted light table, Earth Surf. Proc. Land., 33, 2285–2296, https://doi.org/10.1002/esp.1675, 2008a. a
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Short summary
Mountain streams often display a stepped morphology but the conditions under which these steps form, remain stable, and eventually collapse are still not entirely clear. We run flume experiments to study how (a) the amount of sediment input and (b) channel width variations affect step dynamics in steep channels. Steps form preferentially in areas of flow convergence (channel narrowing) and their frequency is higher when sediment supply is larger than zero but smaller than the transport capacity.
Mountain streams often display a stepped morphology but the conditions under which these steps...
