Abstract: Based on the model of Linxi River diversion project, the authors investigated the effect of layout and energy dissipation mode at the outlet of diversion tunnel on the scour, flow velocity, flow pattern and wave surge in the downstream. We designed different layouts and dissipation modes in the tests. Test results showed that adding guidewall on the side of diversion tunnel outlet could effectively prevent the oppress of main stream on the flow at outlet, and prevent the flow from concentration, which is conducive to flow diffusion. Adding baffle pier at the outlet of diversion tunnel could diffuse the flow in lateral, longitudinal, and vertical directions, thereby reducing the backwater height and the erosion and flow velocity in the downstream.

Key words: flow diversion for construction, baffle pier,  side guide wall, erosion in the downstream, velocity along the banks