Hillslope-channel coupling and geomorphic processes in a sub-humid badlands landscape: Evidence from 10 years of high-spatial resolution topography and hydrologic record

Badlands landscapes are usually subjected to high erosion rates and soil degradation, representing the main source of fine sediments in some catchments, especially in Mediterranean regions. High erosion rates imply high sediment transfer downstream, with associated environmental and management implications. Coupling between hillslope and channel processes has been proved as a critical factor in the evolution of badlands landscapes. This work examines the hillslope-channel coupling and geomorphic processes in a sub-humid badlands landscape using a 10-year dataset of high-resolution topography in relation with hydro-meteorological drivers. Study catchment (0.45 km2) is located in the Central Southern Pyrenees. Topographic datasets were obtained through multi-temporal surveys (i.e., seasonally and annually) carried out by means of Terrestrial Laser Scanner (TLS) and Structure from Motion (SfM) photogrammetry. Hydrologic records were obtained from a gauging station located at the catchment outlet while rainfall was recorded in three tipping-bucket distributed along the study area. The study analyses the relationships between the hillslope erosion and the main-channel incision processes, and how they interact to shape the badlands landscape over time in relation with the hydro-meteorological registers. The study also highlights the importance of high-resolution topography in understanding erosion and the complex interactions between hillslope and channel processes, and the need for continued monitoring to better understand the long-term geomorphic and hydrological processes in these areas.

This work is supported by the MOUNTWATER (TED2021-131982B-I00) research project funded by the MICINN-Plan de Recuperación, Transformación y Resiliencia and the EU-NextGenerationEU.