Discharge and force distribution in a sinuous channel with vegetated floodplains during overbank flow

ABSTRACT

Overbank flow in a sinuous channel with roughened floodplains has been investigated, focusing on the effect of floodplain vegetation on overall flow resistance. The physical model of the Besòs River has allowed analysing the effect of flexible roughness elements which simulate the natural vegetation of rivers. The experimental measurements of horizontal velocities have been used to obtain zonal discharges and forces along a meander wavelength. The results illustrate that although mass transfer is the most important source of energy losses, in rivers with strongly vegetated floodplains the flow resistance increases considerably due to the strong apparent shear forces acting between the main channel and floodplains.

Keywords:

• Apparent shear stress
• mass exchange
• momentum transfer
• overbank flow
• sinuous river
• vegetated floodplains