Mixing processes in vegetated rivers: experimental investigation in a laboratory flume

The presence of vegetation in rivers exerts an important ecological function and is very important to maintain suitable habitat. Especially in recent years, some researchers (among others Perrucca et al., 2007) have focused their attention on the role of vegetation in channel’s morphodynamics. Alteration of hydrological conditions in fluvial systems inevitably leads to changes in river morphology, riparian or riverbed vegetation and ecosystems. Riparian vegetation distribution could also change in time and in space depending on the combination of factors affecting the settling and growth of vegetated elements. In the present paper attention is focused on the turbulent and mixing processes in presence of flexible submerged vegetation. In particular, the process of transport and dispersion of tracers is investigated. The analysis is performed with the aid of detailed experimental data collected in a laboratory channel for different vegetation patches on the bed and for different growth stages of the vegetated elements.