Headwater catchments, comprising hillslopes, valley heads, and colluvial valleys, are critical sources of water, sediments, and nutrients for downstream river networks. As mass movements dominate these landscapes, topographic relief has long been recognized as a primary factor controlling geomorphic processes and the spatial arrangement of geomorphic units in headwater catchments. However, how the transition from hillslope- to channel-dominated processes varies with relief remains debated. Pa...
