A comprehensive study of the river plume in a microtidal setting
Agnese Baldoni (a); Eleonora Perugini (b); Pierluigi Penna (c); Luca Parlagreco (d); Maurizio Brocchini (a);
On the basis of observations and modelling of the plume generated by the Misa River (AN, Italy), we performed a
comprehensive study, which integrated different sources of information (field data, numerical simulations, etc.),
of the generation and transport mechanisms of river plumes flowing into microtidal environments. First, we
analysed images simultaneously acquired by both two shore-based stations and satellite to determine plume
fronts and extensions. Then, we correlated such information with the estuarine forcing to recognize the plume
generation and transport mechanisms. Being real-life events influenced by a combination of factors, we run
numerical simulations to separately study each force and its influence on the plume evolution. We also performed
simulations of two real-life cases, to compare the modelled and observed results. We identified the river
discharge and the wind as the main generation and transport mechanisms, respectively. Moreover, waves could
stir, suspend, and drag plume sediments, even if results showed that a river discharge associated with a return
period smaller than 1 year produced a plume denser than 5-year return period waves. The transport mechanisms
were responsible for the alongshore extension of the plume. The tide, even if secondarily, affected the plume
evolution, depending on its phase shift to the river discharge peak. Particle Tracking Velocimetry from videos
acquired by a shore-based station provided the surface velocity field in the final river stretch. This and the
contributions by wind and waves were correlated with the plume extension through a power law.
2022 - Articolo in rivista
Estuarine, coastal and shelf science (Print) 275 (2022). doi:10.1016/j.ecss.2022.107995
Keywords: River plume, Estuary, Microtidal environment, Large-scale PTV, Numerical modelling