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Concept

Méandre

Publications associées (24)

Morphometry of Tidal Meander Cutoffs Indicates Similarity to Fluvial Morphodynamics

Andrea Rinaldo, Peng Gao

Sinuous channels wandering through coastal wetlands have been thought to lack lateral-migration features like meander cutoffs and oxbows, spurring the broad interpretation that tidal and fluvial meanders differ morphodynamically. Motivated by recent work s ...

Amer Geophysical Union2024

Insights Into the Dynamics of Vegetated Alternate Bars by Means of Flume Experiments

Giulio Calvani

Alternate bars are bedforms recognizable in straight or weakly curved channels as a result of riverbed instability. The length and height of alternate bars scale with the river width and the water depth, respectively. During low water stages, alternate bar ...

American Geophysical Union2023

Clogging of riverbed substrates by fine sediment

Romain Maxime Dubuis

Riverbeds represent the habitat of numerous aquatic species. Exchanges between the groundwater, the hyporheic zone and the surface flow are also essential for river ecosystems. Fine sediment transported by rivers deposits inside or on top of the bed and mo ...

EPFL2023

Influence of channel geomorphic units on bedload transport and river morphology during low‐magnitude bed‐forming floods coupled with sediment augmentation

Giovanni De Cesare, Severin Stähly, Christian Mörtl, Robin Schroff

In this study, we map different types of channel geomorphic units in a sediment-starved, residual-flow reach before and after an artificial flood. Bedload particles of a previous sediment augmentation measure are tracked with passive integrated transponder ...

2023

Inception of Regular Valley Spacing in Fluvial Landscapes: A Linear Stability Analysis

Sara Bonetti

Incipient valley formation in mountainous landscapes is often associated with their presence at a regular spacing under diverse hydroclimatic forcings. Here we provide a formal linear stability theory for a landscape evolution model (LEM) representing the ...

2022

p Spatio-temporal deposition profile of an experimentally produced turbidity current with a continuous suspension supply

Giovanni De Cesare

A turbidity current is a turbulent, particle-laden gravity current that is driven by density differences resulting from the presence of suspended sediment particles. The current travels downslope, bearing a large amount of sediment over a great distance, a ...

2022

Effect of blocked driftwood on the hydraulic performance of a gated standard weir

Giovanni De Cesare, Michael Pfister

Driftwood belongs to riverine ecosystems and is stored and transported in every natural stream. Hydraulic structures built in streams typically alter the flow characteristics and might consequently get in conflict with driftwood. The latter can get trapped ...

International Association for Hydro-Environment Engineering and Research (IAHR)2022

Experimental Study on Bedload Transport and Bedforms: Behaviour and Interplay in Steep Turbulent Streams

Ivan Pascal

In mountain regions, steep streams play an important role in water and sediment connectivity. In these highly dynamic systems, water flow features, sediment fluxes and stream morphologies are tightly interlinked over a broad range of temporal and spatial s ...

EPFL2022

Microbial Ecology of Methanotrophy in Streams Along a Gradient of CH4 Availability

Tom Ian Battin, Hannes Markus Peter, Paraskevi Pramateftaki, Alexandre Bagnoud

Despite the recognition of streams and rivers as sources of methane (CH4) to the atmosphere, the role of CH4 oxidation (MOX) in these ecosystems remains poorly understood to date. Here, we measured the kinetics of MOX in stream sediments of 14 sites to res ...

Frontiers Media SA2020

Ecosystem engineers: Biofilms and the ontogeny of glacier floodplain ecosystems

Tom Ian Battin, Jade Brandani

The term “ecosystem engineering” emerged in the 1990s and is commonly used to refer to the activities of larger organisms like beavers and trees in rivers and streams. The focus on larger organisms may be motivated by their more visible effects on the envi ...

2019

Hydraulic-morphological habitat assessment in rivers considering residual flow, sediment replenishment and artificial flood events

Severin Stähly

Dams store water and trap sediment in their reservoirs. Downstream river segments, hence, are affected by a limited sediment dynamics. This becomes obvious by river bed incision, limited geomorphological variability and depletion of hydraulic habitats for ...

EPFL2019

Image processing and laser measurements for determination of the erosion and deposition of fine sediments by a gravity current

Anton Schleiss, Mário Jorge Rodrigues Pereira Da Franca, Carmelo Juez Jiménez, Jessica Zordan

This paper reports a high-resolution, non-intrusive, low-cost technique to measure volumes of erosion and deposition of fine sediments. The combination of two techniques, photography and laser scanning, gives the advantage of simultaneous quantitative esti ...

IOP Publishing2018

Geomorphic work by gravity currents with varying initial conditions

Jessica Zordan

Gravity currents are density-driven flows that are able to transport high amounts of sediment and are responsible of great geomorphic changes. Moreover they can have severe repercussions on the environment since they are conveyors of substances, e.g. pollu ...

EPFL2018

Morphological resilience to flow fluctuations of fine sediment deposits in bank lateral cavities

Anton Schleiss, Mário Jorge Rodrigues Pereira Da Franca, Carmelo Juez Jiménez

Lateral cavities are built in the banks of rivers for several purposes: to create harbors, to capture sed- iment, to keep a central navigable channel (i.e., Casiers de Girardon in the Rhone river) or to promote the formation of aquatic habitats if a limite ...

2018

Size Ratio of Fluvial Grains’ Intermediate Axes Assessed by Image Processing and Square-Hole Sieving

Severin Stähly

The comparability of grain sizes emerging from different methods are discussed, including image-based grain-size analysis. Waterworked gravel-bed surfaces from laboratory and field experiments are analyzed in detail. Grain sizes estimated using freely avai ...

American Society of Civil Engineers2017

Time-based failure analysis of compressed riverbank riprap

Anton Schleiss, Charles Pfister, Mário Jorge Rodrigues Pereira Da Franca, Mona Jafarnejad Chaghooshi

Methods to design riprap-lined channels usually refer to dumped material. Large blocks placed individually by machinery are used when more stability is required. They offer additional resistance against flow erosion since space between blocks is minimized ...

Taylor & Francis Ltd2017

The dam-break problem for eroding viscoplastic fluids

Christophe Ancey, Belinda Margaret Bates

Natural gravity-driven flows can increase in volume by eroding the bed on which they descend. This process is called basal entrainment and is thought to play a key role in the bulk dynamics of geophysical flows. Although its study is difficult using field ...

Elsevier2017

Gravel bars are sites of increased CO2 outgassing in stream corridors

Tom Ian Battin

Streams are significant sources of CO2 to the atmosphere. Estimates of CO2 evasion fluxes (fCO2) from streams typically relate to the free flowing water but exclude geomorphological structures within the stream corridor. We found that gravel bars (GBs) are ...

Nature Research2017

INFLUENCE OF THE INITIAL VOLUME OF LOCK EXCHANGE GRAVITY CURRENTS ON THE SEDIMENT ENTRAINMENT CAPACITY

Jessica Zordan

In the lock-exchange technique used to produce gravity currents, two fluids of different densities are initially at rest in a tank and separated by a vertical barrier, the lock gate. When this gate is suddenly removed, the two fluids come into contact and, ...

2017

Modeling Flow Pattern and Evolution of Meandering Channels with a Nonlinear Model

Koen Blanckaert

Meander dynamics has been the focus of river engineering for decades; however, it remains a challenge for researchers to precisely replicate natural evolution processes of meandering channels with numerical models due to the high nonlinearity of the govern ...

Mdpi Ag2016