Geomorphic (dis)connectivity in a middle-mountain context: Human interventions in the landscape modify catchment-scale sediment cascades

The nature of geomorphic connectivity in headwater mountainous catchments influences the delivery of sediment to the downstream channel network. A reduced sediment supply from mountainous regions results in channel instability and loss of physical habitats. The aim of this study is to show how the small, mid-mountainous Cerna Opava catchment in the Czech Republic is organised in terms of sediment sources, sinks and (dis)connectivity of sediment transport. A field-based approach combining GIS analysis and geomorphological mapping was adopted to unravel the nature of present-day sediment delivery to the channel network. When the lithology and land use of an area are relatively uniform, the sediment delivery to the channel network varies spatially, according to slope-channel connectivity and the distribution of in-channel sources (cut banks and incising reaches). Despite sediment supply being limited by forested slopes and a number of natural and anthropogenic in-channel barriers, stream channels display no signs of "hungry water" conditions.