Stepped spillways for embankment dams. Review, progress and development in overflow hydraulics

In recent years a number of embankmentswere designed with concrete overtopping protection shaped in a stepped fashion. During large overflows on stepped chutes, there is no skin friction between mainstream and steps, and flow resistance is basically form drag. Alterations of flow recirculation and of fluid exchanges between free-stream and cavity flow are discussed in this study.A comprehensive series of air-water flow measurements on embankment dam stepped chute are presented. The introduction of vanes demonstrates turbulence manipulation and form drag modification that could lead to more efficient designs.