Can flume-derived formulations predict the effect of riparian vegetation on flow in rivers?

The effect of riparian vegetation on the flow has been explored by various studies in flume setups with simplified vegetation mimics and idealized flow conditions. Due to lack of similar field studies, it is not clear how transferable the flume findings are to natural rivers, where the morphology and vegetation patterns are more complex. This study presents high-frequency flow velocity measurements across a small sandy lowland river with riparian vegeta-tion, and explores similarities and differences with related flume studies. The measurements in the river revealed well-defined shear layers at the bank vegetation edges accompanied by large-scale turbulent structures, in accordance with flume studies. Semi-empirical equations from the flume literature predicted the flow velocities and shear stresses reasonably well at some parts, but not so well in others, particularly near the vegetation edge, highlighting the modelling chal-lenges in natural river systems.