Energy Dissipation on Rough Stepped Spillways

In this research, the effects of rough steps on the performance of stepped spillways in terms of energy dissipation were tested. To this end, two types of roughness including uniform and discrete were applied to the surface of the steps. For uniform roughness, sand with a given grain size and, for discrete roughness, fine blocks with specific dimensions were used. The results demonstrated that in the napped flow regime, roughing the steps increased the performance of stepped spillways regarding energy dissipation about 15-20% as compared with smooth stepped spillways. In terms of energy dissipation, the uniform rough stepped spillways are more efficient than the discrete rough stepped spillways.