We demonstrate that landscapes with more planar initial conditions tend to have lower mean junction angles. Geomorphic processes on alluvial piedmonts result in especially planar initial conditions, consistent with a correlation between junction angles and the presence/absence of Late Cenozoic alluvial deposits and the constraint imposed by the intersection of planar approximations to the topography upslope from tributary junctions. We caution against using junction angles to infer paleoclimate.

Many Earth surface processes are controlled by the spatial pattern of surface water flow. We review commonly used methods for predicting such spatial patterns in digital landform models and document the pros and cons of commonly used methods. We propose a new method that is designed to minimize those limitations and show that it works well in a variety of test cases.

In order to interpret the formation processes of subsurface salt wedges and polygonal patterned grounds from the northern Atacama Desert, we present a multi-methodological approach. Due to the high salt content of the wedges, we suggest that their formation is dominated by subsurface salt dynamics requiring moisture. We assume that the climatic conditions during the wedge growth were slightly wetter than today, offering the potential to use the wedges as palaeoclimate archives.

Channel–hillslope coupling in landscape evolution models can strongly affect channel profiles. When hillslope diffusion is applied everywhere and only topography is tracked, a new scaling predicts how detachment-limited channels steepen with hillslope diffusion. Field data support channel steepening to transport sediment but not as predicted by the scaling, highlighting the need for a critical inspection of channel–hillslope coupling approaches.

Despite the critical role of water in alpine regions, its presence in bedrock is frequently neglected. This research examines the dynamics of water in fractures using 1 decade of measurements from a tunnel 50 m underground. We provide new insights into alpine groundwater dynamics, revealing that up to 800 L d^-1 can flow in one fracture during extreme events. These quantities can saturate the fractures, enhance hydraulic conductivity, and generate pressures that destabilize slopes.