Publications associées à Parameterization of the logarithmic layer of double-averaged streamwise velocity profiles in gravel-bed river flows

Stochastic Simulations and Machine Learning Modeling to Predict Bedload Transport and Bed Topography

In computational hydraulics models, predicting bed topography and bedload transport with sufficient accuracy remains a significant challenge. An accurate assessment of a river's sediment transport rate necessitates a prior understanding of its bed topograp ...

EPFL2024

Morphological processes and potential for lacustrine delta restoration

Giovanni De Cesare, Stéphanie Joëlle André, Alexandre Philippe Louis Antoine Fourrier

Most lacustrine deltas are nowadays highly anthropized systems. River training works during past centuries considered rivers mainly as vectors of water and sediments from a point source to a sink. However, numerous problems have been identified by resident ...

2024

Laterally unconfined neutral or negative buoyancy inflow into a quiescent ambient over sloping bottom

Haoran Shi

This work studies the nearshore hydrodynamics of a shallow turbulent flow entering a laterally unconfined quiescent ambient with a sloping bottom boundary. Examples of such flow are neutrally buoyant ebb tidal jets and hyperpycnal river plumes entering ope ...

EPFL2023

Hydromorphological assessment of sediment augmentation measures in gravel-bed rivers

Christian Mörtl

In the riverine environment, the riverscape, sediment and flow regime are essential drivers for natural habitat dynamics. Today, most water courses in Europe are regulated, and their natural dynamics are impaired. Flood releases coupled with the artificial ...

EPFL2023

Reduction of riverbed clogging related to sediment flushing

Giovanni De Cesare, Romain Maxime Dubuis

The ecological effects of dams on sediment and river flow have been subject to an increasing attention, leading to the implementation of mitigation measures such as environmental flow release and sediment replenishment. However, fine sediment dynamics have ...

CRC Press/Balkema2023

GALET: A deep learning image segmentation model for drone-based grain size analysis of gravel bars

Giovanni De Cesare, Christian Mörtl

In this study, we present the deep learning image segmentation model for drone-based grain size analysis of gravel bars called GALET. The objectives are to quantify the performance of the code and to test its applicability in river research and management. ...

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

Estimating Mean Bedload Transport Rates and Their Uncertainty

Christophe Ancey, Ivan Pascal

Measuring bedload transport rates usually involves measuring the flux of sediment or collecting sediment during a certain interval of time Δt. Because bedload transport rates exhibit significant non‐Gaussian fluctuations, their time‐averaged rates depend a ...

2020

Modeling turbulent stream flows over rough permeable beds

Christophe Ancey, Gauthier Paul Daniel Marie Rousseau, Ivan Pascal

In steep streams, turbulent flows run over coarse sediments that are similar in size to flow depth. Under these conditions, a significant part of the flow may seep through the permeable bed. Based on experimental data, this paper presents a model able to r ...

CRC Press2020

Continuously-fed density currents over impermeable and porous substrates

Sara Venuleo

Gravity currents are buoyancy-driven flows having a significant impact on the environment and human life. They can be observed in a vast range of natural and anthropogenic scenarios, such as seawater and freshwater, the atmosphere, or industrial processes. ...

EPFL2020

Testing diﬀerent (e)DNA metabarcoding approaches to assess aquatic oligochaete diversity and the biological quality of sediments

Régis Lionel Vivien

Aquatic oligochaetes are important bioindicators of sediment quality in watercourses and lakes, but their morphological identiﬁcation to the species level is challenging and sometimes impossible. The use of DNA barcoding and metabarcoding could greatly fac ...

2019

Application of an Ensemble Kalman filter to a semi-distributed hydrological flood forecasting system in alpine catchments

Giovanni De Cesare, Javier García Hernández, Alain Tommy Foehn, Anne Schwob

One of the key success factor for hydrological forecasts is the establishment of initial conditions that represent well the conditions of the simulated basin at the beginning of the forecast. Real-time Data Assimilation (DA) has been shown to allow improvi ...

2019

Bar dynamics and sediment transport pulses in gravel-bed channels

Christophe Ancey, Blaise Etienne Marceau Dhont

Mountain rivers exhibit sediment transport rate fluctuations that often cover more than two orders of magnitude. Bedform migration is often cited as the key process that causes giant fluctuations in the sediment transport rate. To quantify the effect of be ...

EDP Sciences2018

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

Sediment Pulses in a Gravel-Bed Flume with Alternate Bars

Blaise Etienne Marceau Dhont

The proper understanding of gravel-bed river dynamics is a crucial issue for the effective protection against related natural hazards, design of hydraulic structures, and preservation of their high ecological value in mountain regions. However, despite mor ...

EPFL2017

Hydrodynamics of mountain-river confluences and its relationship to sediment transport

Mário Jorge Rodrigues Pereira Da Franca, Sebastián Guillén Ludeña

Mountain confluences are characterized by narrow and steep tributaries that provide important sediment load to the confluence, whereas themain channel supplies the dominant flow discharge. This results in a marked bed discordance between the tributary and ...

American Geophysical Union2017

Entrainment,motion, and deposition of coarse particles transported by water over a sloping mobile bed

Christophe Ancey, Joris Heyman

In gravel bed rivers, bed load transport exhibits considerable variability in time and space. Recently, stochastic bed load transport theories have been developed to address the mechanisms and effects of bed load transport fluctuations. Stochastic models i ...

Wiley-Blackwell2016

Wall-Roughness Effects on Flow and Scouring in Curved Channels with Gravel Beds

Anton Schleiss, Mário Jorge Rodrigues Pereira Da Franca

Due to a complex three-dimensional flow pattern, the outer banks of river bends are predisposed to erosion. When endangering civil structures, preventing measures to mitigate this erosion are thus required. Vertical ribs at protection walls for scour reduc ...

Asce-Amer Soc Civil Engineers2016

Particle diffusion in non-equilibrium bedload transport simulations

Christophe Ancey

This paper examines the importance of particle diffusion relative to advection in bed load transport. Particle diffusion is not included in existing approaches to bedload transport. Based on recent advances in the probabilistic theory of sediment transport ...

Elsevier Science Inc2016

Velocity profiles of turbidity currents flowing over a flat bed

Giovanni De Cesare, Anton Schleiss, Sabine Chamoun

Turbidity currents are the main source of suspended sediment transport in reservoirs and thus one of the main causes of sedimentation. One of the techniques used to avoid reservoir sedimentation is through venting of turbidity currents. In the framework of ...

2016