Large-Eddy Simulation (LES) technique has been applied to calculate the three-dimensional turbulent unsteady flow in the real intake channel of a small-scale hydroelectric power station. The method computes the motion of the free surface with a modified HSMAC method. The turbulence is modeled with a modified Smagorinsky sub-grid scale model with near-wall damping. With the total number of grid points of about one million, the complex and unsteady flow with localized vorticity can be reproduced reasonably well for the basic configuration as well as the case with a vortex-suppressing device. By using a similar grid that marginally resolves the near-wall flow, it may be used for predicting similar intake flows. The turbulence model, however needs an improvement to better representhe flow impinging on the end wall.