Recent  

Erosion is a threat for soils with rainfall as the driving force. The annual rainfall erosivity factor quantifies rainfall impact by analysing high-resolution rainfall time series (~ 5 min). Due to a lack of measuring stations, alternatives for its estimation are analysed in this study. The best results are obtained for regionalisation of the erosivity factor itself. However, the identified minimum of 60-year time series length suggests using rainfall generators as in this study as well.

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 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.

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.

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.

To assess the effects of differences in grain-size distribution within debris flows on the morphology of debris-flow fans, fan morphologies were modeled experimentally. Even if debris flows exhibited similar flow properties, their runout distance differed in response to differences in their grain-size distribution. Differences in runout distance were responsible for variations in the direction of the descending flow that resulted in different debris-flow fan morphology.

We mapped and dated 187 earthflows to determine controls on earthflow formation and resulting topographic changes in the Teanaway basin, central Washington State, USA. Using a new relative dating technique and absolute dating, we find that 25 % of earthflows were active in the last ~500 years. Earthflows are lithologically controlled, actively narrow valleys, and increase sediment loads.

A levee-building model is presented to investigate the effects of flood on levee slope and river behaviors. Coarser grains that cause steep levee slopes lead to frequent switchings of river paths, but higher overflow velocity has an opposite effect. High levee slopes lead to more reoccupations of abandoned old river paths than low levee slopes when rivers switch their locations. The study helps us to assess flood hazards with river-path switching.

Himalayan rivers are full of giant boulders that rarely move except during glacial lake outburst floods (GLOFs), which therefore must be important drivers of erosion in the Himalayas. GLOFs are rare, so little is known about their long-term erosional impact. We found that rivers in Nepal have channel geometry that, compared with markers of upstream glaciation, confirm GLOFs as a major control on erosion. This previously unrecognized control should be accounted for in landscape evolution studies.

Climate change is rapidly altering high-alpine landscapes. The formation of new lakes in areas becoming ice free due to glacier retreat is one of the many consequences of this process. Here, we provide an estimate for the number, size, time of emergence, and sediment infill of future glacier lakes that will emerge in the Swiss Alps. We estimate that up to ~ 680 potential lakes could form over the course of the 21st century, with the potential to hold a total water volume of up to ~ 1.16 km³.

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 the fraction of soil components needed to predict subsurface storage and fluxes of water, carbon, and nutrients.

Many studies on modeling landform evolution have focused on mountain ranges, while large parts of Earth's surface are quite flat and alluvial plains have been preferred locations for human settlements. Conducting large-scale simulations of fluvial erosion and sediment transport, this study reveals that rivers in a tectonically inactive foreland are much more dynamic than rivers in a mountain range; the local redistribution of deposits in the foreland is the main driver of the dynamics.

Climate change fundamentally alters glaciated high-alpine areas, but it is unclear how this affects riverine sediment transport. As a first step, we aimed to identify the most important processes and source areas in three nested catchments in the Ötztal, Austria, in the past 15 years. We found that areas above 2500 m were crucial and that summer rainstorms were less influential than glacier melt. These findings provide a baseline for studies on future changes in high-alpine sediment dynamics.

During the late Pleistocene, the incision of the Trinity River valley left behind terraces. Elevation data and measurements of abandoned channels preserved on terraces are used to evaluate how terraces formed. We find a transition in the style of terraces with age from those associated with external environmental forcings to those produced by internal river migration changes. This result shows the importance of several indicators (i.e., channel bends, elevations) in determining terrace form.

Rock glaciers are some of the most frequently occurring landforms containing ice in mountain environments. Here, we use field observations, analysis of aerial and satellite images, and dating methods to investigate the activity of the rock glacier of the Vallon de la Route in the French Alps. Our results suggest that the rock glacier is characterized by two major episodes of activity and that the rock glacier system promotes the maintenance of mountain erosion.

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 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.

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.

There is an increasing demand for tidal-marsh restoration around the world. We have developed a new modeling approach to reduce the uncertainty associated with this development. Its application to a real tidal-marsh restoration project in northwestern Europe illustrates how the rate of landscape development can be steered by restoration design, with important consequences for restored tidal-marsh resilience to increasing sea level rise and decreasing sediment supply.

Erosion modulates Earth's carbon cycle by exposing a variety of lithologies to chemical weathering. We measured water chemistry in streams on the eastern Tibetan Plateau that drain either metasedimentary or granitoid rocks. With increasing erosion, weathering shifts from being a CO₂ sink to being a CO₂ source for both lithologies. However, metasedimentary rocks typically weather 2–10 times faster than granitoids, with implications for the role of lithology in modulating the carbon cycle.

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. The Mont Blanc massif has the highest erosion and therefore dominates the sediment flux of the Dora Baltea river.

Our work is focused on describing how and why the terrace levels of central Amazonia were formed during the last 100 000 years. We propose to address this question through a landscape evolution numerical model. Our results show that terrace levels at lower elevation were established in response to dry–wet climate changes and the older terrace levels at higher elevations most likely formed in response to a previously higher elevation of the regional base level.

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 occur. Our study highlights the importance of the hypotheses made regarding the threshold that river discharge needs to exceed in order to effectively cut down into the bedrock.

River valleys are important components of mountain systems: they are the most fertile part of landscapes and store sediment which is transported from mountains to surrounding basins. Our knowledge of the location and shape of valleys is hindered by our ability to measure them over large areas. We present a new method for measuring the width of mountain valleys continuously along river channels from digital topography and show that our method can be used to test common models of river widening.