Rivers with alternating patterns of shallow and deep flows are commonly observed where a river widens and then narrows, respectively. But what if width changes over time? We use a lab experiment to address this question and find it is possible to decrease and then increase river width at a specific location and observe that flows deepen and then shallow consistent with expectations. Our observations can inform river restoration and climate adaptation programs that emphasize river corridors.

We recorded yearly images of a bar of the Vieux-Habitants river, a river located on Basse-Terre (Guadeloupe). These images, combined with measurements of the river discharge, allow us to monitor the evolution of the population of boulders. We estimate the smallest discharge that can move the boulders and calculate the effective transport time. We show that the likelihood of a given boulder remaining at the same location decreases exponentially, with an effective residence time of 17 h.

One of the reasons for lower ground temperatures in coarse, blocky terrain is a low or varying soil moisture content, which most permafrost modelling studies did not take into account. We used the CryoGrid community model to successfully simulate this effect and found markedly lower temperatures in well-drained, blocky deposits compared to other set-ups. The inclusion of this drainage effect is another step towards a better model representation of blocky mountain terrain in permafrost regions.

We measured the surface area of minerals in two 21 m cores from soil to bedrock to test hypotheses on the formation of the surface area of weathered rock. A sharp increase in high-surface-area secondary minerals extended from 3 m to the ground surface. Half the total surface area was from corroded iron minerals, which form in the presence of oxygen, even though corroded iron comprised less than 0.1 % of the rock. Element removal by rock dissolution started at 7 m but did not form new minerals.

Scarpland formation produced low-inclined slopes susceptible to deep-seated landsliding on geological scales. These landslide-affected slopes are often used for forestry activities today, and interaction between geology and vegetation controls shallow landsliding. Our data show that Feuerletten clays control deep-seated landsliding processes that can be reactivated. When trees are sufficiently dense to provide lateral root cohesion, trees can prevent the occurrence of shallow landslides.