In this Letter, a kinetic energy sandpile model, taking into account of grain inertia and the moving directions of the toppling grain, is developed and used to study the behaviour of sandpiles. In our model, the inertial effects are based on the toppling kinetic energy. The phenomenon of sandpile formation by revolving rivers is reproduced with the model, revolving velocity ω∼t^{−2/3} and ∼h^{−3/2}, where t is the simulation time and h is the height of the sandpile.