To protect hydropower intakes a three dimensional hydrodynamic CFD model can be used to simulate the streamlines, sediment transport and local scour accurately upstream of a bottom outlet or sediment flushing tunnel. This paper focuses on the simulation of flow and sediment transport patterns upstream of a dam bottom outlet. This paper first describes the development of a coupled fully three-dimensional (3D) numerical model for the prediction of the local pressured sediment flushing scour upstream of the bottom outlet for non-cohesive sediments. The presented numerical model solves the Reynolds averaged Navier-Stokes equations in conjunction with the k − ε turbulent model which include both sediment transport and hydrodynamic parameters. The proposed coupled fully 3D numerical model is later validated against experimental tests using non-cohesive sediments. Results from these simulations are in good agreement with the measurements in terms of the geometric features of the scour hole as well as the velocity field upstream of the bottom outlet.