A vertical sorting model for rivers with non-uniform sediment and dunes

Vertical sorting fluxes and the resulting organisation of grain size fractions over bed elevations, i.e. the vertical sorting profile, influence bedform dimensions and the bed surface composition. As a result, they will affect the bed roughness, the rate and composition of the sediment transport, the large-scale river morphology, and water levels during floods. An important problemof presentmorphologicalmodel systems for rivers with non-uniform sediment is their neglect of vertical sorting fluxes other than through net aggradation or degradation. The objective of the present study is to develop a method in order to better account for vertical sorting processes in the river bed