Abstract The condition of emergent or submerged vegetation plays a vital role in affecting the flow behaviour in open channels. To understand the flow processes in free surface flows under emergent rigid vegetation condition, an extensive experimental investigation is performed in a laboratory channel with staggered combination of emergent rigid vegetation. Three‐dimensional velocities data are collected by ADV at various section and position of vegetated channel. The three‐dimensional flow properties such as velocity distribution, turbulence intensity, turbulent kinetic energy, Reynolds shear stress in vegetation, and non‐disturbed region are analysed and compared with the longitudinal and transverse length of vegetated zone. In the vegetation region, the longitudinal velocity in free stream region decreases as compared with non‐disturbed region. However, the vertical velocity also decreases in free stream region except at the centre line of channel cross‐section. Variations in velocity in the vegetation section were observed because of the local effect induced by the vegetation stems. Three‐dimensional Reynolds shear stress and turbulent intensity were weaker in magnitude at vegetation region. The presence of vegetation reduces the longitudinal profile of flow velocity, Reynolds shear stress and turbulence intensities, which means that vegetation can be used as an effective tool to reduce the flow resistance. The turbulent kinetic energy, skewness and kurtosis are also evaluated and compared between the vegetated and non‐vegetated zone. The outcomes of the results provide an important view to understand flow behaviour at immediately front and immediately behind of vegetation stem.
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