River systems across the global have long been inherently related to human development. Although most civilizations formed and thrived along rivers, they can represent a source of risks during floods, and suffer from anthropogenic pressures and global change.
Sediment transport processes at the scale of grains
- Luca Mao investigates the dynamic of the armor layer and sediment clusters in gravel-bed rivers affected by floods of different magnitude and floods occurring in different sequences. Investigations are carried out in laboratory flumes, although currently efforts focus more on the use of tagged particles in the field.
The role of vegetation and large wood in river processes
The group focuses on identifying and quantifying the role of vegetation and large wood in determining the shape and morphological changes or gravel-bed rivers. Past investigations used flume experiments to observe channel changes caused by vegetation encroaching on sand-bedded rivers, and also focused on quantifying the role of land use change in the delivery of large wood to Andean headwater streams. Current investigations focus on the role of vegetation management (clearcut vs. three hinging vs. no interventions) on roughness in low-gradient rivers.
Human impacts in river systems
The group focuses on assessing the short- and long-term effects of direct and indirect human disturbances on river systems. Dr. Luca Mao focuses especially on the role of dams and hydropower plants operations on sediment transport and channel changes, and on the long-term effects on gravel mining in large gravel-bed rivers in Chile.
Tufa growth and the geometry of tufa barrages in streams
Tufa is the solid precipitation of calcium carbonate in freshwater systems. Under certain physicochemical characteristics of water and local geomorphological setting, tufa can grow a few mm per year, and can create staircase-like sequences of barrages that determine the morphology and ecology of streams. MSc student Antonia Foley monitors the growth of tufa in a stream of Lincolnshire and investigates the geometry of tufa barrages.