Computational results are presented for uniform approach flow past emergency gate model, placed in a 2–D channel with free water surface, for two cases: (1) fixed gate and (2) gate moving perpendicular to the water flow. The calculations were made in the dimensionless system, for the assumed Reynolds number Re = 106. The velocity field and vorticity field were determined by vortex method. On this basis the pressure distribution profile and hydrodynamic force were determined by means of boundary elements method. The vortex structures and the evolution of vortex shedding are illustrated by velocity field of vortex blobs for both cases – fixed and movable gate. We also presented the distribution of the pressure coefficient alongside the gate edge as well as the derivative lift and drag coefficients. The average force coefficients agree very well with the experimental values. The movement of downward of the gate substantially increases the calculated value of the lift coefficient.