Recent  

We present a method to extract surface change information from 4D time series of topographic point clouds, recorded with a terrestrial laser scanner. The method uses information on the sensor to spatially and temporally smooth the data, reducing uncertainties. The Kalman filter used for the temporal smoothing also allows to interpolate over data gaps or extrapolate into the future. Clustering areas where change histories are similar allows us to identify processes that may have the same causes.

In our study, we developed, tested and applied a cost-effective Time-Of-flight camera to autonomously monitor the rainfall-driven and animal-driven sediment redistribution in areas affected by burrowing animals with high temporal (four times a day) and spatial (6 mm) resolution. We estimated the sediment redistribution rates on a burrow scale and then upscaled the redistribution rates to the entire hillslopes. Our findings can be implemented into long-term soil erosion models.

Climate change will fundamentally alter glaciated high alpine areas, but how this affects river sediments is still unclear. In this study, we investigated data of the past 15 years and found that areas above 2500 m are crucial for sediment transport in rivers draining three glaciated catchments in the Ötztal, Austria, while summer rainstorms were less influential for sediment dynamics than glaciers. Our findings provide a baseline for studies on future changes of high alpine sediment dynamics.

Vegetation influences how rivers change through time, yet the way in which we analyse vegetation is limited. Current methods collect detailed data at the individual plant level or determine dominant vegetation types across larger areas. Herein, we use UAVs to collect detailed vegetation datasets for a 1 km length of river and link vegetation properties to channel evolution occurring within the study site, providing a new method for investigating the influence of vegetation on river systems.

Two simulations are performed using mono-granular and multi-granular flows with the same average grain size, while all the other conditions were kept the same. The mono-granular flow formed a symmetric-like fan morphology as there was less avulsion during formative processes. The multi-granular flows resulted in bilaterally widened avulsions during the early stages of the inundation, and the runout directions shifted as the topography evolved, and resulted in asymmetric fan morphology.

Abrupt changes in tectonic uplift rates induce sharp changes in river profile, called knickpoints. When river erosion depends non-linearly on slope, we develop an analytic model for knickpoint velocity and find the condition of two knickpoint merging. Then we develop analytic models that represent the two-directional link between tectonic changes and river profile evolution. The derivation provides new understanding on the links between tectonic changes and river profile evolution.

As riverbank collapse and bank-collapsed materials transportation are important contributing factors among river evolution and geomorphic processes, a series of flume experiments were conducted to quantify transformation for cohesive bank-collapsed materials. transportation in terms of energy dissipation. The results made a valuable addition to current state of the art in understanding and characterising sediment transport.

River beds are often composed of different scales of dunes, who’s size and shape is highly variable over time and space. Characterization of these dunes is important in many research studies focused on fluvial processes. A new tool is presented here that aims to identify different scales of dunes from river bed elevation maps. A first step is to separate two scales of bedforms, without smoothing steep slopes of the larger dunes. In a second step, dunes are identified and properties are computed.

This paper presents a novel methodology to identify and quantitatively analyze deposition and erosion patterns in ephemeral ponds or in perennial lakes with strong water level fluctuations. We apply this method to unravel the water and sediment balance of Lac Wégnia, a designated RAMSAR site in Mali. The study can be a showcase for monitoring Sahelian lakes using remote sensing data, as it sheds light on the actual drivers of change in Sahelian lakes.

Using landscape evolution models integrating mantle dynamics, climate, eustatism and surface processes, we break down a previous idea that considers mantle flow as the main driver of the pulse of sedimentation in the Orange Basin, SA, over the last 30 Ma. Instead, climate impact seems to be a predominant mechanism. We also show that sediment flux and landscape evolution in the region is the product of interlinked processes accounting for both lithology variations, mantle dynamics and climate.

A levee-building model is presented to demonstrate the effects of flood conditions on levee slope, linking with river avulsion processes. Input grain size and levee slope are positively correlated with avulsion frequency, but overflow velocity is inversely related to it. High levee slopes develop local avulsions whereas low slopes develop regional avulsions. The link between the levee geometry and avulsion behaviours provides a better assessment of the flood hazards triggered by avulsion.

We present first physics-based general landslide velocity model incorporating internal deformation & external forces. Voellmy & inviscid Burgers’ equation are specifications of the novel advective-dissipative system. Our unified analytical solutions constitute new foundation of landslide velocity, provide practitioners key information in instantly estimating impact forces. Solutions describe breaking wave & folding, revealing landslide dynamics are architectured by advection, reigned by forcing.

Alpine landscapes are transformed by several erosion processes. ¹⁰Be concentrations measured in river sediments at the outlet of a basin represent a powerful tool to quantify how fast the catchment erodes. We measured erosion rates within the Dora Baltea catchments (western Italian Alps). Our results show that erosion is governed by topography, bedrock resistance and glacial imprint: hard lithologies support high reliefs affected by glacial/periglacial processes and recurring rock fall events.

This manuscript 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.

River avulsions (rivers suddenly changing course) redirect water and sediment. These floods can harm people and control how some landscapes evolve. We model how abandoned channels from older avulsions affect where, when, and why future avulsions occur in mountain-front areas. We show that abandoned channels can push and pull avulsions, and the way they heal controls landscapes. Avulsion models should include abandoned channels; we also highlight opportunities for future field workers.

This paper proposes a method to estimate thermal diffusivity and its uncertainty over time, at numerous locations and at an unprecedented vertical spatial resolution from soil temperature time-series. We validate and apply this method to synthetic and field case studies. The improved quantification of soil thermal properties is a cornerstone for advancing the indirect estimation of fraction of soil components needed to predict the subsurface storage and fluxes of water, carbon, and nutrients.

When mountains grow, rocks are brought to the surface of the Earth. Weathering of these rocks changes the concentration of CO₂ in the atmosphere, but the direction of that change may depend on the type of rock. We measured chemistry of stream waters draining three different rock types. We find that for all types, increasing erosion of rocks shifts weathering from reactions that draw down CO₂ to reactions that emit CO₂. The emission may be strongest where rocks from deep in the crust are exposed.

Floodplain formation in estuaries limit the ebb and flood flow, reducing channel migration, and shortening the tidally-influenced reach. Vegetation establishment on bars reduces local flow velocity and concentrates flow into channels, while mud flats fill accommodation space and reduce channel migration. These results are based on experimental estuaries in the Metronome facility supported by numerical flow modelling.

We recorded yearly images of a bar of the Vieux-Habitants river, a river located on Basse-Terre (Guadeloupe). These images, combined with measurements of the river discharge, allow us to monitor the evolution of the population of boulders. We estimate the smallest discharge that can move the boulders, and calculate the effective transport time. We show that likelihood of a given boulder remaining at the same location decreases exponentially, with an effective residence time of 17 hours.

Landscape evolution is highly dependent on climatic parameters and the occurrence of intense precipitation events is considered to be an important driver of river incision. We compare the rate of erosion with the variability of river discharge in a mountainous landscape of SE France where high magnitude floods regularly occurs. Our study highlights the importance of the hypotheses made on the threshold that river discharge need to exceed in order to effectively cut down into the bedrock.

By comparing two models for the transport of sediment, we find that they share a similar steady-state solution that adequately predicts the shape of most depositional systems made of a fan and an alluvial plain. The length of the fan is controlled by the size of the mountain drainage area feeding the sedimentary system and its slope by the incoming sedimentary flux. We show that the models differ by their transient behavior to external forcing and are characterized by different response times.

Arctic rivers erode into permafrost and mobilize organic carbon, which can react to form greenhouse gasses or get re-buried in floodplain deposits. We collected samples on a permafrost floodplain in Alaska to determine if more carbon is eroded or deposited by river meandering. The floodplain contained a mixture of young carbon fixed by the biosphere and old, re-deposited carbon. Thus, sediment storage may allow Arctic river floodplains to retain aged organic carbon even when permafrost thaws.

To study channel network development following continental glaciation, we ran small physical experiments where networks slowly expanded into flat surfaces. By changing substrate and rainfall, we altered flow pathways between the surface and subsurface. Initially, most channels grew by overland flow. As relief increased, erosion through groundwater sapping occurred, especially in runs with high infiltration and low cohesion, highlighting the importance of groundwater in channel network evolution.