Document Type : Case Report

Authors

1 Master Alumni, Department of Water and Environment, Faculty of Civil Engineering, Iran University of Science and Technology, Tehran, Iran

2 Professor, Department of Water and Environment, Faculty of Civil Engineering, Iran University of Science and Technology, Tehran, Iran

3 M.Sc. Student, Department of Water and Hydraulic Structures, Faculty of Civil Engineering, University of Tehran, Tehran, Iran

Abstract

Flow resistance in rivers with vegetation patches is one of the challenging parameters in river engineering. This study aimed to investigate the effect of vegetation patches on flow resistance in Shapur, Fahlian, and Dalaki rivers. The data measured in this study include velocity measurement, surveying, and bed sampling. In this study, considering the simplifying assumptions, the equation for the flow resistance due to vegetation patches was derivated. Accordingly, the flow resistance due to vegetation patches was obtained by the difference in the flow resistance due to bed from the value of the total flow resistance for each section. The results show that the average percentage of vegetation patches’ contribution from the total flow resistance is 44%, which shows the significant effect of vegetation patches on flow resistance. In addition, an investigation of 71 measured velocity profiles showed the phenomenon of Dip in the velocity profiles near the vegetation patches, and by moving away from the vegetation patches, the effect of this phenomenon is reduced and the profiles become S-shaped.

Keywords

Main Subjects

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