Bedrock channels are the conveyor belts of mountain regions, evacuating sediment produced by erosion. Bedrock channel morphology and dynamics affect sediment transport rates and local erosion and set the base level for hillslope response. Here, using mechanistic considerations of the processes of fluvial erosion and transport, and considerations of the mass balance of sediment and bedrock, I discuss the principles governing steady-state channel morphology and the dynamic paths to achieve it.

Standing on a riverbank, it is usually obvious which direction the river flows. However, when observing a river from space, we cannot see the flowing water and must use other clues to determine flow directions. For complicated river channel networks like those of deltas and braided rivers, determining the flow direction of each channel within the network is not trivial. We present and demonstrate a method to automatically determine flow directions for each link in aerially viewed river channels.

Using experiments, we found that the form and behaviour of a river depends on its ability to move the larger of its constituents. The manner in which all particles move depends upon the rate and calibre of the supplied material, as well as the rate of supplied water. This goes against the prevailing theory of a single important and representative grain size under depositing conditions, and these results may alter how we interpret river deposits to explain their formation.

The evolution of the drainage system in the Eastern Alps is inherently linked to different tectonic stages. This leads to a situation in which major orogen-parallel alpine rivers, such as the Salzach and the Enns, are characterized by elongated east–west-oriented catchments. We investigate the stability of present-day drainage divides and the stability of reconstructed paleo-drainage systems. Our results indicate a progressive stability of the network towards the present-day situation.

Scaling relationships mathematically describe how two geometric traits of a geomorphic feature change relative to each other in a systematic way (how length changes with area in drainage basins and sedimentary deposits, for example). Here we demonstrate the emergence of scaling relationships in coastal overwash morphology. These findings may help to predict overwash deposition and offer insight into how spatial patterns in overwash morphology may self-organise.

Extreme rainfall is expected to intensify with increasing temperatures, which will likely affect rainfall spatial structure. The spatial variability of rainfall can affect streamflow and sediment transport volumes and peaks. The sensitivity of the hydro-morphological response to changes in the structure of heavy rainfall was investigated. It was found that the morphological components are more sensitive to changes in rainfall spatial structure in comparison to the hydrological components.

We studied coastal sea floor terraces in parts of the Baltic Sea using various types of sonar data, sediment cores, and video. Terraces (~1 m high, > 100 m long) are widespread in depths < 15 m and are formed in glacial clay. Our study supports an origin from groundwater flow through silty layers, undermining overlying layers when discharged at the sea floor. Submarine groundwater discharge like this may be a significant source of freshwater to the Baltic Sea that needs to be studied further.

This work is the first assessment of the suitability of the in situ ¹⁰Be method to determine denudation rates from fine (50–100 μm) detrital quartz at the watershed scale. This method is used worldwide to determine denudation rates from sandy sediments (250 μm^-1 mm). We show that in the Var catchment fine-grained sediments (50–100 μm) are suited to the ¹⁰Be method, which is vital for future applications of ¹⁰Be in sedimentary archives such as offshore sediments.

The topographic steady-state assumption is often used in geomorphology. However, recent studies suggest that a drainage network is more mobile than previously thought. Using landscape evolution models, we show that those migrations have a significant impact on basin-wide denudation rates even if an overall topographic steady state is achieved at large scale. Our approach provides new tools to derive minimal uncertainties in basin-scale denudation rates due to this topographic disequilibrium.