Morphodynamic differences induced by different confluence angles in widen confluences
River widening is commonly used as a solution for the rehabilitation of rivers with the main purposes of allowing the river to adjust to its natural dynamics and to improve riparian and instream habitat for flora and fauna, by increasing the heterogeneity in substrate, flow and morphology. Local widening may also be used for confluences rehabilitation as, for many of them, the heterogeneity and fragmentation of the river system were severely affected by previous human interventions. Local tributary widening amplifies the morphodynamic processes, enhancing the diversity in sediment substrate, flow velocities and flow depths. In addition, widening should neither affect aspects such as water level in the tributary nor in the main channel, which is an important consideration for flood safety. The aim of this paper is to analyze the differences in terms of bed morphology and flow dynamics induced by different confluence angles in widen channel confluences.