Floodplain vegetation has an important influence on the flow and sediment transport and river bend migration, especially when flood overflows the main channel. The influence of dense floodplain vegetation on the height of secondary current cell and the position of the center of the cell was investigated through physical experiments in which the artificial grass was deployed on the floodplain to simulate floodplain vegetation. The experimental results indicated that the floodplain vegetation affected the height of secondary current cell most significantly at cross-over sections. The height of the cell was equal to the bankfull level in the non-vegetated channel, but was equal to the sum of the bankfull level and the canopy height. The floodplain vegetation increased the bankfull level equivalently. In a meandering bend, the influence of vegetation on the height of secondary current cell reduced gradually, and then was negligible at the apex section. Based on experimental observations, a method for predicting the position of secondary current cell was proposed and verified using the data from a different source, indicating that this method was capable of accurately predicting the position. Finally, the relation between the relative intensity of secondary current cell and the ratio of main channel discharge and total discharge was discussed. Regardless of whether vegetation was fixed on the floodplain or not, the maximal discharge ratio occurred at apex section in all scenarios. As the main channel depth increased, the difference between the ratios in non-vegetated channel and vegetated channel was reduced. When the main channel depth was close to or smaller than the sum of canopy height and bankfull level, the characteristics of secondary current cell along a meandering reach in the channel with overbank flows would be similar to those in a channel with inbank flows.
