Fluvial levees in compound channels: a review on formation processes and the impact of bedforms and vegetation

Abstract

AbstractNatural levees are wedge-shaped morphological features developing along the boundaries of mass flows. When they form in fluvial landscapes, they can have multiple implications for river management of trained inland rivers. This paper summarizes the present knowledge in regard to the formation and evolution of so-called fluvial levees of trained inland river sections and provides novel hypotheses in regard to the significance of bedforms and vegetation strips along the floodplain on levee formation, evolution, and characteristics. The hypotheses that (i) bedforms contribute to levee formation by altering the interface hydraulics between the main channel and the floodplain and enhancing entrainment of sediment into suspension and (ii) vegetation stripes along the floodplain additionally affect the interface hydraulics resulting in a changed levee geometry are supported by combining existing knowledge on bedform dynamics and flow-vegetation-sediment interaction with results reported in recent flume studies.