Abstract: This article focuses on flood discharge and energy dissipation problems in a hydropower station ? the spillway is designed with a great range of capacity but its axis is nearly normal to the direction of river mainstream. For this spillway, we have developed a new swallow-tailed array flip bucket and examined its hydraulics and scour power using laboratory tests on a 1:60 scale model and comparing it with a continuous flip bucket and a swallow-tailed flip bucket. The experiment showed that the new flip bucket split the jet nappe into a multi-strand flow, making the water jet sufficiently stretched in a limited space. The multi-strand nappe was aerated obviously and falling down on the scour pool surface over an area larger than that of the other two flip buckets. The scope and intensity of the fluctuations caused by nappe plunging into the scour pool was decreased significantly so that its power of scour on the riverbed and river banks were much lowered. Thus, the swallow-tailed array flip bucket is an effective device of energy dissipation and erosion control for spillways with a large crossing angle to the river mainstream.