A Preliminary Study of Field Scour Morphology Downstream of Block Ramps Located at River Bends

Block ramps are usually located in natural rivers. In particular, the location of the structure in river bends contributes to deeply modifying both the upstream inflow conditions and the downstream erosive process. The scour mechanism is affected by the kinematic field asymmetry, resulting in a significant three-dimensionality of the scour features. Therefore, it appears fundamental to deepen the erosive process occurring in correspondence with such structures in order to provide insights on the physics of the phenomenon and improve existing design criteria. Based on both field measurements conducted in the Porębianka River and laboratory model results, this manuscript presents a preliminary analysis of the resulting equilibrium morphologies downstream of block ramps located in river bends by highlighting the effect of the main hydraulic and geometric parameters on the scour lengths as well as on sediment bar formation.