This study presents a new reduced-complexity model with few parameters linked to basic physical processes, which aims to reproduce the transport of sediment as bed load and the formation and stability of channel morphology in steep mountain streams. The model is able to simulate the formation and stability of steps, bed structures commonly encountered in steep channels, by assuming that their formation is due to intense sediment transport during high flows causing jamming of particles.

We mapped and analysed nearly 2000 large valleys that were formed by meltwater flowing under a former ice sheet. Our results demonstrate that valleys tend to cluster together in distinctive networks. The valleys themselves are typically < 20 km long, and 0.5–3 km wide, and their morphology is strongly influenced by local bed conditions (e.g. topography) and hydrology. We suggest valleys formed gradually, with secondary contributions from flood drainage of water stored on top of or under the ice.

We assess particle transport and storage patterns through channel confluences in mountainous headwater streams. Using passive sediment tracers, we note the location of efficient transport corridors in confluences and compare dispersion against a non-confluence control reach. We suggest that certain confluence types may represent locations of enhanced sediment transport in river networks and encourage further investigation.

This paper generalises the physical dependence of the relationship between contributing area, local slope, and the surface soil grading first described by Cohen et al. (2009, 2010) using a soil evolution model called SSSPAM. We show the influence of weathering on the equilibrium soil profile and its spatial distribution. We conclude that the soil grading relationship is robust and will occur for most equilibrium soils. This spatial organisation is also true below the surface.

High-resolution topographic data are becoming more prevalent, yet many areas of geomorphic interest do not have such data available. We produce topographic data at a range of resolutions to explore the influence of decreasing resolution of data on geomorphic analysis. We test the accuracy of the calculation of curvature, a hillslope sediment transport coefficient, and the identification of channel networks, providing guidelines for future use of these methods on low-resolution topographic data.

Cosmogenic nuclide concentrations are widely used to calculate catchment-averaged denudation rates. Despite their widespread use, there is currently no open source method for calculating such rates, and the methods used to calculate catchment-averaged denudation rates vary widely between studies. Here we present an automated, open-source method for calculating basin averaged denudation rates, which may be used as a stand-alone calculator or as a front end to popular online calculators.

Rivers export the products of continental weathering to the oceans. It is important to accurately constrain these fluxes to better understand global biogeochemical cycles. The riverine export of major cation species in particular contributes to regulate the long-term carbon cycle. In this work we quantify some additional fluxes to the ocean that may occur when solid sediments react with seawater in estuaries. These fluxes have been only poorly constrained so far.

Accurately predicting gravel transport rates in mountain rivers is difficult because of feedbacks with channel morphology. River bed surfaces evolve during floods, influencing transport rates. I propose that the threshold of gravel motion is a state variable for channel reach evolution. I develop a new model to predict how transport thresholds evolve as a function of transport rate, and then use laboratory flume experiments to calibrate and validate the model.

We appraise the success of a novel mitigation approach and subsequent adaptive management, designed to reduce the transfer of fine sediment in a small upland catchment in the UK. Analysis of the river response demonstrates that the fluvial sediment system has become more restrictive with reduced fine sediment transfer. The study demonstrates that channel reconfiguration can be effective in mitigating fine sediment flux in upland streams but the full value of this may take many years to achieve.

The interdisciplinarity of geomorphometry is its greatest strength and one of its major challenges. This special issue showcases exciting developments that are the building blocks for the next step-change in the field. In reading and compiling the contributions we hope that the scientific community will be inspired to seek out collaborations and share ideas across subject-boundaries, between technique-developers and users, enabling us as a community to gather knowledge from our digital landscape

Rapid dissolution of bedrock and regolith mobilised by landslides can be an important control on rates of overall chemical weathering in mountain ranges. In this study we analysed a number of landslides and rivers in Taiwan to better understand why this occurs. We find that sulfuric acid resulting from rapid oxidation of highly reactive sulfides in landslide deposits drives the intense weathering and can set catchment-scale solute budgets. This could be a CO₂ source in fast-eroding mountains.

The main objective of this research is to analyze rock avalanche dynamics by means of a detailed structural analysis of the deposits coming from data of 3-D measurements. The studied deposits are of different magnitude: (1) decimeter level scale laboratory experiments and (2) well-studied rock avalanches. Filtering techniques were developed and applied to a 3-D dataset in order to detect fault structures present in the deposits and to propose kinematic mechanisms for the propagation.

Landscape evolution models are driven by climate or precipitation data. We show that higher-resolution data lead to greater basin sediment yields (> 100 % increase) despite minimal changes in hydrological outputs. Spatially, simulations over 1000 years show finer-resolution data lead to a systematic bias of more erosion in headwater streams with more deposition in valley floors. This could have important implications for the long-term predictions of past and present landscape evolution models.