Organisms evolve in ever-changing environments under complex process interactions. We applied a new software modelling tool to assess how changes in river course impact the evolution of riverine species. Models illustrate the climatically and tectonically forced landscape changes that can drive riverine biodiversity, especially where topographic relief is low. This research demonstrates that river course changes can contribute to the high riverine biodiversity found in real-world lowland basins.

During the last ice age, sea level was lower, and the North Sea was land. The margin of a large ice sheet was at Dogger Bank in the North Sea. This ice sheet formed large rivers. After the ice sheet retreated down from the high point of Dogger Bank, the rivers had no water supply and dried out. Increased precipitation during the 15 000 years of land exposure at Dogger Bank formed a new drainage network. This study shows how glaciation and climate changes can control how drainage networks evolve.

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.

Many contemporary models of large-scale fluvial erosion focus on the detachment-limited regime where all material entrained by the river is immediately excavated. This limitation facilitates the comparison with real river profiles and strongly reduces the numerical complexity. Here a simple formulation for the opposite case, transport-limited erosion, and a new numerical scheme that achieves almost the same numerical efficiency as detachment-limited models are presented.

Part of the inaccuracies when estimating bed load transport in gravel-bed rivers is because we are not considering the wide distributions of shear stress in these systems. We modified a subsurface-based bed load transport equation to include these distributions. By doing so, our approach accurately predicts bed load transport rates when the pavement layer is still present, while the original one predicts zero transport. For high flows, our method had similar performance to the original equation.

We propose a machine learning approach for the classification and analysis of large delta systems. The approach uses remotely sensed data, channel network extraction, and the analysis of 10 metrics to identify clusters of islands with similar characteristics. The 12 clusters are grouped in six main classes related to morphological processes acting on the system. The approach allows us to identify spatial patterns in large river deltas to inform modeling and the collection of field observations.

Alternate bars are large sediment deposits that tend to naturally form in rivers when the channel width is sufficiently large. Our laboratory experiments on a scaled model reveal that equilibrium properties of self-formed alternate bars highly depend on the water discharge with respect to the relevant theoretical thresholds. This work provides fundamental information for predicting the response of rivers to natural or human alterations of the flow regime.

Large boulders found in two Himalayan valleys show signs of long fluvial transport (>10 km). Paleo-discharges required to mobilize these boulders exceed typical monsoon discharges. Exposure dating shows that a cluster of these boulders was emplaced ca. 5 kyr ago. This period is coeval with a weakening of the Indian monsoon and glacier retreat in the area. We, therefore, suggest that glacier lake outburst floods are likely mechanisms that can explain these exceptional transport processes.

Climate warming is causing significant ice surface lowering even in the uppermost parts of alpine glaciers. Using terrestrial lidar, we quantify rockfall in freshly exposed cirque walls. During 6-year monitoring (2011–2017), an extensive dataset was established and over 600 rockfall events identified. Drastically increased rockfall activity following ice retreat can clearly be observed as 60 % of the rockfall volume detached from less than 10 m above the glacier surface.

Rockfall size and frequency in two deglaciating cirques in the Central Alps, Austria, is analysed based on 6-year rockwall monitoring with terrestrial lidar (2011–2017). The erosion rates derived from this dataset are very high due to a frequent occurrence of large rockfalls in freshly deglaciated areas. The results obtained are important for rockfall hazard assessments, as, in rockwalls affected by glacier retreat, historical rockfall patterns are not good predictors of future events.

We calculated the probability of sediment transport in coarse-grained mountainous streams in the Alps and the Andes where data on water discharge is available. We find a positive correlation between the predicted probability of sediment transport and the grain size sorting of the bed material. We suggest that besides sediment discharge, the bedload sorting exerts a significant influence on the mobility of sediment and thus on the stability of gravel bars in mountainous streams.

This study provides an extensive review of field- and laboratory-scale studies and mathematical models used for predicting the sediment processes in bedrock river channels. We tested the model capabilities by reproducing and comparing the results with laboratory-scale experiments. This study provides an insight into the strengths and shortcomings of various available models.

Our new Holocene sea level curve is not only different to previously published data but also different to global glacio-isostatic adjustment (GIA) models. We see that as soon as ice melting has ceased, local processes control shoreline migration and coast evolution. This indicates that more emphasis should be placed on regional coast and sea-level change modelling under a global future of rising sea level as local government needs more specific and effective advice to deal with coastal flooding.

We study the dynamics of suspended matter and associated nutrients in large rivers in Germany. The relationship between suspended sediment concentration and discharge is diagnostic of the processes and sources of suspended matter. We show that suspended matter originates from organic growth within the river at low flow and from soil erosion at high flow. In a warmer climate with increased frequency of droughts, low flow states are likely to be more prolonged, affecting the behavior of rivers.