Elham Vahidi - University of Tehran, Karaj, Iran
Mohammad Hossein Omid - Professor, Department of Irrigation & Reclamation Engineering, University of Tehran, Karaj, Iran.

Vegetation is an important factor in river geomorphology due to its effects on bed and bank erosion and sediment transportation. In this study 38 series of steady, gradually varied flow experiments were performed in a rectangular rigid boundary flume. Two types of flow, i.e. with and without sediment were used to investigate the impact of un-submerged rigid vegetation-like elements on the flow conditions. The results show that the presence of un-submerged rigid vegetation increases the resistance to flow and the total shear stress. Also the results prove that the measured bed-load transport data are very close to the results obtained from the Ashida & Michiue’s bed-load transport equation

Vegetation, Drag force, Shear stress, Bed-load transport