Scour control and surface sediment distribution downstream of block ramps

Block ramps or rock chutes are structures characterized by large bed slopes. They are increasingly used as river bed stabilization measures because of their particular capacity to sustain the river morphology and biological continuity. The scour process downstream of block ramps is an important research topic in engineering practice that must be controlled to ensure their structural stability. The purpose of this study is to analyze the scour downstream of a block ramp, in presence of a rock sill located in the stilling basin. The effect of sills is analyzed for non-uniform bed material. A dimensional analysis resulted in physically based dimensionless groups controlling the profile of the scour hole. The sediment distribution of the non-uniform bed mixtures at the scour equilibrium configuration is studied. The surface sediment redistribution is investigated for different scour typologies and the effect of protection work is also analyzed.