Incipient motion of sediment in the presence of emergent rigid vegetation

This paper investigates the incipient motion of sediment in open channels covered with emergent rigid vegetation, which is represented by arrays of circular cylinders arranged in a regular pattern. The criterion for incipient motion is continuous sediment yield from the vegetation zone. The experiments conducted showed that with emergent vegetation, motion of local sediment was initiated before the incipient condition. The data obtained were used to derive an equation for the incipient motion velocity with vegetation coverage, which was observed to be smaller than that without vegetation. The experimental results indicated that the vegetated density had the most significant influence of the factors considered on the incipient motion velocity. The ratio of the velocity with formation of an uneven bed to the velocity for incipient sediment transport was found to have a constant value of 0.76.

► The criterion for the incipient motion with vegetation is different.
► An equation of incipient motion velocity with the vegetation coverage was derived.
► It indicated the effect of vegetation on the incipient motion.
► The effect of vegetation on the soil erosion.