Erosive and Hydrodynamic Processes Analysis Downstream of Low-head Rock Made Control Structures.

Stream restoration structures analysis and design are some of the most important topics for hydraulic engineers. In the last decades, a particular attention has been reserved to low-environment impact structures, which have the peculiarity to conjugate hydraulic functioning and environmental care. Their advantage is to harmonize and minimize the impact on natural contests and, at the same time, they offer flexible solutions which can be easily modified and adapted to various scenarios. In particular, these structure typologies are widely used for river restoration both to control sediment transport and to dissipate flow energy, in order to reduce erosive processes. The present paper aims to analyze different low-head rock made control structures in terms of scour hole morphology characteristics for different hydraulic conditions and geometric configurations. Namely, the performance comparison in terms of scour hole depths and hydrodynamic behavior is conducted in the presence of four different rock made structures: rock grade control structures, stepped gabion weirs, block ramps, and cross-vane weirs. The analysis involves a detailed comparison of energy dissipation process and scour hole characteristics, highlighting similitudes and differences in the respective ranges of application.