Temporal and spatial interactions between river bed roughness, geometry, bedload transport and flow hydraulics in mountain streams

Abstract

The study explores the influence of bedload transport and flow hydraulics on the spatial and temporal dynamics of bed roughness and geometry in mountain streams. In order to investigate these complex interrelationships, each topic is treated separately. A new relative roughness coefficient, K3, is applied in the spatial and temporal roughness analyses. Detailed analyses of the highly variable natural fluid and sedimentary interactions are performed in the three mountain streams instead of using an estimated mean shear stress value to predict and describe river bed dynamics. Finally, the spatial and temporal interrelationships between roughness, geometry, flow dynamics and bedload transport are summarised in the new F.A.S.T. (Fluid And Sediment Transfer) model.